A Ti/Pt/Co Multilayer Stack for Transfer Function Based Magnetic Force Microscopy Calibrations
Baha Sakar, Sibylle Sievers, Alexander Fernández Scarioni, Felipe Garcia-Sanchez, İlker Öztoprak, Hans Werner Schumacher, Osman Öztürk
Subject: Physical Sciences, Acoustics Keywords: magnetic force microscopy; calibration; reference samples; micromagnetism; metrology for magnetism; magnetic Multilayers
Magnetic force microscopy (MFM) is a widespread technique for imaging magnetic structures with a resolution of some 10 nanometers. MFM can be calibrated to obtain quantitative (qMFM) spatially resolved magnetization data in units of A/m by determining the calibrated point spread function of the instrument, its instrument calibration function (ICF), from a measurement of a well-known reference sample. Beyond quantifying the MFM data, a deconvolution of the MFM image data with the ICF also corrects the smearing caused by the finite width of the MFM tip stray field distribution. However, the quality of the calibration depends critically on the calculability of the magnetization distribution of the reference sample. Here, we discuss a Ti/Pt/Co multilayer stack which shows a stripe domain pattern as a suitable reference material. A precise control of the fabrication process combined with a characterization of the sample micromagnetic parameters allows to reliably calculate the sample's magnetic stray field, proven by a very good agreement between micromagnetic simulations and qMFM measurements. A calibrated qMFM measurement using the Ti/Pt/Co stack as a reference sample is shown and validated and the application area for quantitative MFM measurements calibrated with the Ti/Pt/Co stack is discussed.
Vector Potential, Magnetic Field, Mutual Inductance, Magnetic Force, Torque and Stiffness Calculation between Current-Carrying Arc Segments with Inclined Axes in Air
Slobodan Babic
Subject: Physical Sciences, Applied Physics Keywords: Magnetic vector potential; magnetic field; mutual inductance; magnetic force; torque; stiffness
In this paper we give the improved and new analytical and semi-analytical expression for calcu-lating the magnetic vector potential, magnetic field, magnetic force, mutual inductance, torque, and stiffness between two inclined current-carrying arc segments in air. The expressions are ob-tained either in the analytical form over the incomplete elliptic integrals of the first and the sec-ond time or by the single numerical integration of some elliptical integrals of the first and the second kind. The validity of the presented formulas is proved from the special cases when the inclined circular loops are treated. We mention that all formulas are obtain by the integral ap-proach except the stiffness which is found by the derivative of the magnetic force.
Cognate DNA Recognition by Engrailed Homeodomain Involves a Conformational Change Controlled via an Electrostatic-Spring-Loaded Latch
Nicola D'Amelio, Benjamin Tanielian, Mourad Sadqi, Pilar Lopez-Navajas, Victor Victor Muñoz
Subject: Chemistry, Analytical Chemistry Keywords: protein-DNA interactions; DNA recognition; transcription factors; DNA binding domains; con-formational change; nuclear magnetic resonance; circular dichroism; control of gene expression; homeodomains.
Transcription factors must scan genomic DNA, recognize the cognate sequence of their control element(s), and bind tightly to them. The DNA recognition process is primarily carried out by their DNA binding domains (DBD), which interact with the cognate site with high affinity and more weakly with any other DNA sequence. DBDs are generally thought to bind to their cognate DNA without changing conformation (lock-and-key). Here we used nuclear magnetic resonance and circular dichroism to investigate the interplay between DNA recognition and DBD conformation in the Engrailed homeodomain (EnHD), as model case for the homeodomain family of eukaryotic DBDs. We found that the conformational ensemble of EnHD is rather flexible and becomes more structured as ionic strength increases following a Debye-Hückel's dependence. Our analysis indicates that EnHD's response to ionic strength is mediated by a built-in electrostatic spring-loaded latch that operates as conformational transducer. We also found that, at moderate ionic strengths, EnHD changes conformation upon binding to cognate DNA. This change is of larger amplitude and somewhat orthogonal to the response to ionic strength. As a consequence, very high ionic strengths (e.g. 700 mM) block the electrostatic-spring-loaded latch and binding to cognate DNA becomes lock-and-key. However, the interplay between EnHD conformation and cognate DNA binding is robust across a range of ionic strengths (i.e. 45 to 300 mM) that covers the most physiologically-relevant conditions. Therefore, our results demonstrate the presence of a mechanism for the conformational control of cognate DNA recognition on a eukaryotic DBD. This mechanism can function as a signal transducer that immediately locks the DBD in place upon encountering the cognate site during active DNA scanning. The electrostatic-spring-loaded latch of EnHD can also enable the fine control of DNA recognition in response to local/temporal changes in ionic strength induced by variate physiological processes.
Unified Theory of Gravity, Electromagnetic Force, Strong and Weak Forces and Their Applications
Sheng Qin
Subject: Physical Sciences, General & Theoretical Physics Keywords: unified theory of force; Gravitation; Electromagnetic force; Weak force; Strong force; Inverse square law; Galaxy rotation curve; The origin of magnetic field; Charged particle radiation; Maxwell displacement current; Black hole structure; Radiation effect of moving magnet
This paper first explains the theory of the origin of force from a new perspective, explaining that the origin of all forces is caused by the "missing of energy in the time dimension" (non-conservation in a certain period of time), and constructs a unified theory of force on this basis. Then, through the unified theory of force, the following phenomena are reinterpreted: (1) The common origin of the inverse square law of gravitation and electromagnetic force; (2) The origin of the repulsive force of electrons and protons at small distances; (3) The mystery of the rotation curve of galaxies and the new explanation of "dark matter"; (4) explain the origin of the magnetic field; (5) Predict that moving magnets have the same radiation effect as charged particles (electron magnetic moments also have radiation effects); (6) Reinterpret Maxwell's displacement current; (7) Reinterpret synchrotron radiation and bremsstrahlung; (8) Explain that the strong and weak forces are short-range forces; (9) Predict the true structure of black holes and the origin of gravitational waves;(10) Possible explanation for the origin of the speed of light.
Optimization Methodology of the Magnetic Navigation System with Gradient and Uniform Saddle Coils
Sungjun Kim, Mingyu Cho, Seyeong Im, Joongho Yun, Jaekwang Nam
Subject: Engineering, Electrical & Electronic Engineering Keywords: magnetic navigation system; saddle coil; optimization; magnetic robot; magnetic field
The magnetic navigation system (MNS) with gradient and uniform saddle coils is one of the effective systems to manipulate various medical magnetic robot due to its compact structure and uniformity of the magnetic field and field gradient. However, it has limited operating time and large inductance effect due to the high current density and numerous turns of coils, respectively. In this paper, we propose an optimization methodology of the MNS considering the current density and inductance of the coils. We introduce objective functions, constraints, and design variables of the MNS. Then, the MNS was designed by an optimization algorithm. The constructed MNS was compared with the conventional MNS, and it could generate 22 % stronger magnetic field or field gradient while the maximum three-dimensional rotating magnetic field was improved by 42 %. We also demonstrated an unclogging performance of a helical robot was improved by 54 % with the constructed MNS.
Polarity Free Magnetic Repulsion and Magnetic Bound State
Hamdi Ucar
Subject: Physical Sciences, General & Theoretical Physics Keywords: magnetic bound state; magnetic levitation; polarity free repulsion; magnetic trapping
This is a report on a dynamic autonomous magnetic interaction which does not depend on polarities resulting in short ranged repulsion involving one or more inertial bodies and a new class of bound state based on this interaction. Both effects are new to the literature, found so far. Experimental results are generalized and reported qualitatively. Working principles of these effects are provided within classical mechanics and found consistent with observations and simulations. The effects are based on the interaction of a rigid and finite inertial body (an object having mass and moment of inertia) endowed with a magnetic moment with a cyclic inhomogeneous magnetic field which does not require to have a local minimum. Such a body having some DoF involved in driven harmonic motion by this interaction can experience a net force in the direction of the weak field regardless of its position and orientation or can find stable equilibrium with the field itself autonomously. The former is called polarity free magnetic repulsion and the latter magnetic bound state. Experiments show that a bound state can be obtained between two free bodies having magnetic dipole moment. Various schemes of trapping bodies having magnetic moments by rotating fields are realized as well as rotating bodies trapped by a static dipole field in presence of gravity. Also, a special case of bound state called bipolar bound state between free dipole bodies is investigated.
Electronic Surveillance and Security Applications of Magnetic Microwires
Valentina Zhukova, Paula Corte-Leon, Juan Maria Blanco, Mihail Ipatov, Julian Gonzalez, Arcady Zhukov
Subject: Physical Sciences, Acoustics Keywords: magnetic microwires; magnetic bistability; magnetic tag; electronic surveillance; domain wall propagation; post-processing; magnetic anisotropy; magnetostatic interaction.
Applications in security and electronic surveillance require combination of excellent magnetic softness with good mechanical and anti-corrosive properties and low dimensionality. We overviewed the properties of soft magnetic glass-coated microwires and different post-processing making them quite attractive for electronic article surveillance and security applications. We studied the magnetostatic interaction between the microwires and routes to tune the non-linear hysteresis loops by using the arrays of different types of amorphous microwires. The presence of neighbouring microwire (either Fe or Co-based) significantly affects the hysteresis loop of the whole microwires array. In a microwires array containing magnetically bistable microwires we observed splitting of the initially rectangular hysteresis loop with a number of Barkhausen jumps correlated with the number of magnetically bistable microwires. Essentially, non-linear and irregular hysteresis loops have been observed in mixed arrays containing Fe and Co-rich microwires. The observed non-linearity in hysteresis loops allowed to increase the harmonics and tune their magnetic field dependencies. Non-linear hysteresis loops have been also observed upon devitrification of amorphous microwires. On the other hand, several routes allowing to tune the switching field by either post-processing or modifying the magnetoelastic anisotropy have been reviewed. Observed unique combination of magnetic properties together with thin dimensions and excellent mechanical and anti-corrosive properties provide excellent perspectives for the use of glass-coated microwires for security and electronic surveillance applications.
Optimization of Magnetic Properties of Magnetic Microwires by Post-Processing
Valentina Zhukova, Paula Corte-León, Lorena Gonzalez-Legarreta, Ahmed Talaat, Juan Maria Blanco, Mihail Ipatov, Jesus Olivera, Arcady Zhukov
Subject: Materials Science, General Materials Science Keywords: Magnetic microwires; post-processing; hysteresis loops; magnetic anisotropy
The influence of post-processing conditions on the magnetic properties of amorphous and nanocrystalline microwires have been thoroughly analyzed, paying attention on the influence of magnetoelastic, induced and magnetocrystalline anisotropies on the hysteresis loops of Fe-, Ni- and Co-rich microwires. We showed that magnetic properties of glass-coated microwires can be tuned by the selection of appropriate chemical composition and geometry in as-prepared state or further considerably modified by appropriate post-processing, which consists of either annealing or glass-coated removal. Furthermore, stress-annealing or Joule heating can further effectively modify the magnetic properties of amorphous magnetic microwires owing to induced magnetic anisotropy. Devitrification of microwires can be useful for either magnetic softening or magnetic hardening of the microwires. Depending on the chemical composition of the metallic nucleus and on structural features (grain size, precipitating phases) nanocrystalline microwires can exhibit either soft magnetic properties or semi-hard magnetic properties. We demonstrated that the microwires with coercivities from 1 A/m to 40 kA/m can be prepared.
Modeling Hysteresis Loops of Self-Developed Soft Magnetic Composite Cores Using the Jiles-Atherton-Sablik Theory
Adam Jakubas, Krzysztof Chwastek
Subject: Engineering, Electrical & Electronic Engineering Keywords: soft magnetic composites; magnetic properties; Jiles-Atherton model
Magnetic properties of soft magnetic composites are highly sensitive to the processing conditions. In this paper we focus on the possibility to model this effect using the Jiles-Atherton-Sablik theory. It is assumed that the effect of varying compaction pressure may be described by direct introduction of stress-dependent term in the model equations. The values of model parameters are kept constant. Verification of the proposed approach is carried out using measurement data from self-developed iron-based composite cores.
Continuous High-Flow System to Trap and Separate Magnetic Particles from Liquid Mixtures
Georgios Banis, Maria Elisavet Kouli, Evangelos Hristoforou, Angelo Ferraro
Subject: Engineering, Other Keywords: Bio-separation, magnetic separation, magnetic particles, continuous-flow
Bio-separation of natural molecules as well as clinical compounds has been constantly developed in last decades. Several techniques are available but the majority of them presents drawbacks such us impossibility to be applied for industrial purposes. The main limitations for the scaling up are high costs and the fact that the devices work with microfluid dynamics. Nevertheless, magnetic bio-separation is considered the most prone to be used for large scale applications. Herein, we propose a simple magnetic separation method that is not based on microfluid dynamics, can work in a continuous- and high-flow rate and can be easily automated in order to be used for standard separation purposes. It is based on the use of an anisotropic flexible ferric magnetic strip, Teflon hoses and a pumping device. We show the modelling of the separation process along with an experimental test on iron oxide magnetic particles. The results showed that it is possible to remove, and separately collect, more than 92% of magnetic particles from a liquid solution of 100 ml in roughly 15 minutes.
Magnetic Field of a Linear Quadrupole Using the Magnetic Sensors Inside the Smartphones
Isabel Escobar, Raquel Ramirez-Vazquez, Jesus Gonzalez-Rubio, Augusto Belendez, Enrique Arribas
Subject: Physical Sciences, General & Theoretical Physics Keywords: smartphone; magnetic sensor, magnetic field; lab physics; quadrupole
We believe that a natural focus of the Physics Education Research community is on understanding and improving student learning in our physics courses. For this purpose, we are introducing smartphones in the physics laboratory. Current smartphones measure each component of the magnetic field, bearing in mind that any current perpendicular to a magnetic field produces a small potential difference, transversal to the said current, being this voltage easily measurable by Hall sensors. In this work, we have considered the magnetic field created by a linear quadrupole and we have studied its dependence on distance. Using an experimental procedure that is simple we have measured the magnetic field using the Hall sensor that most smartphones have, together with the corresponding app. The purpose of this work is to show that the laboratory is a powerful tool that increases significant learning under three conditions: 1) the practice must not be too sophisticated; 2) students must handle objects in the lab; and 3) the practice must be scientifically accurate, including the adjustments by minimum squares, and the following and necessary error calculation.
Scanning Magnetic Microscope Using A Hall-Effect Sensor for Images of Remanent Magnetization Fields
Jefferson F. D. F. Araujo, Angela A. P. Correa, Elder Yokoyama, Andre L. A. dos Reis, Vanderlei C. Oliveira Jr., Leonardo A. F. Mendoza, Marcos A. C. Pacheco, Cleanio Luz-Lima, Amanda F. Santos, Fredy G. Osorio G., Giancarlo E. Brito, Wagner W. R. Araujo, Tahir Tahir, Antonio C. Bruno, Tommaso Del Rosso
Subject: Physical Sciences, Applied Physics Keywords: scanning magnetic microscopy; Hall sensor; magnetic measurements; geological sample
Scanning magnetic microscopy is a new tool that has recently been used to map magnetic fields with good spatial resolution and field sensitivity. This technology has great advantages over other instruments; for example, its operation does not require cryogenic technology, which reduces its operational cost and complexity. Here, we describe the construction of a customizing scanning magnetic microscope based on commercial Hall-effect sensors at room temperature that achieves a spatial resolution of 200 µm. Two scanning stages on the x- and y-axes of precision, consisting of two coupled actuators, control the position of the sample, and this microscope can operate inside or outside a magnetic shield. We obtained magnetic field sensitivities better than 521 nTrms/√Hz between 1 and 10 Hz, which correspond to a magnetic momentum sensitivity of 9.20 × 10–10 Am2. In order to demonstrate the capability of the microscopy, polished thin sections of geological samples, samples containing microparticles and magnetic nanoparticles were measured. For the geological samples, a theoretical model was adapted from the magnetic maps obtained by the equipment. Vector field maps are valuable tools for the magnetic interpretation of samples with a high spatial variability of magnetization. These maps can provide comprehensive information regarding the spatial distribution of magnetic carriers. In addition, this model may be useful for characterizing isolated areas over samples or investigating the spatial magnetization distribution of bulk samples at the micro and millimeter scales. As an auxiliary technique, a magnetic sweep map was created using Raman spectroscopy; this map allowed the verification of different minerals in the samples. This equipment can be useful for many applications that require samples that need to be mapped without a magnetic field at room temperature, including rock magnetism, the nondestructive testing of steel materials and the testing of biological samples. The equipment can not only be used in cutting-edge research but also serve as a teaching tool to introduce undergraduate, master's and Ph.D. students to the measurement methods and processing techniques used in scanning magnetic microscopy.
Characterizing Complex Mineral Structures in Thin Section of Geological Sample with a Scanning Hall Effect Microscope
Jefferson F. D. F. Araujo, Andre L. A. dos Reis, Vanderlei C. Oliveia, Amanda F. Santos, Cleanio Luz-Lima, Elder Yokoyama, Leonardo A. F. Mendozaand, Joao M. Perreira, Antonio C. Bruno
Subject: Physical Sciences, Applied Physics Keywords: magnetic scanning microscope; hall sensor; magnetic materials; geological sample
We improved a magnetic scanning microscope for measuring the magnetic properties of minerals in thin sections of geological samples at submillimeter scales. The microscope is comprised of a 200 µm diameter Hall sensor that is 142 µm from the sample; an electromagnet capable of applying to the sample up to 500 mT dc magnetic fields over a 40 mm diameter region; a second Hall sensor arranged in a gradiometric configuration to cancel the background signal applied by the electromagnet and reduce overall noise in the system; a custom-designed electronics to bias the sensors and provide adjustment for background signal cancelation; and a scanning XY stage with micrometer resolution. Our system achieves a spatial resolution of 220 µm with noise at 6.0 Hz of »300 nTrms/(Hz)1/2 in an unshielded environment. The magnetic moment sensitivity is 1.3 × 10−11 Am2.1/2 We successfully measured the representative magnetization of a geological sample using an alternative model that takes into account the sample geometry and identified different micrometric characteristics in the sample slice.
Smartphones Magnetic Sensors within Physics Lab
Subject: Physical Sciences, Applied Physics Keywords: smartphone; magnetic hall sensor, magnetic field; lab physics; quadrupole
Current smartphones incorporate different types of sensors that allow us to know our spatial position, they give us information about pressure, speed, acceleration, time, acoustic level, and other different physical magnitudes. These smartphones measure each component of the magnetic field, bearing in mind that any current perpendicular to a magnetic field produces a small potential difference, transversal to the said current, being this voltage easily measurable by Hall sensors. With the implementation of three Hall sensors, and an appropriate app, we can measure the three components of the magnetic field vector, and with this we can obtain information and deduce properties of the physical systems considered. In this paper we are exploring the use of smartphones in a physics laboratory for freshman students. To do this, we have measured, using Hall sensors, the magnetic field created by a linear quadrature, and we have obtained, first of all, its dependence on the distance between the quadrupole and the magnetic sensor. The second purpose of this work is to show that the laboratory is a powerful tool that increases the significant learning of freshman students through advanced technological tools.
Magnetoliposomes Containing Multicore Nanoparticles and a New Thienopyridine Antitumor Compound for Chemo/Thermotherapy
Fábio A. C. Lopes, André V. F. Fernandes, Juliana M. Rodrigues, Maria-João R. P. Queiroz, Bernardo G. Almeida, Ana Pires, André M. Pereira, João P. Araújo, Ana Rita O. Rodrigues, Elisabete M. S. Castanheira, Paulo J. G. Coutinho
Subject: Materials Science, Biomaterials Keywords: multicore magnetic nanoparticles; magnetoliposomes; magnetic hyperthermia; antitumor thienopyridine derivative; chemotherapy
Multicore magnetic nanoparticles of manganese ferrite were prepared using carboxymethyl-dextran and melamine as agglutinating agents. The nanoparticles prepared using melamine exhibit a flower-shape structure, a saturation magnetization of 6.16 emu/g and good capabilities for magnetic hyperthermia. Magnetoliposome-like structures containing the multicore nanoparticles exhibit sizes in the range 250 – 400 nm. A new antitumor thienopyridine derivative was loaded in these nanocarriers with a high encapsulation efficiency of 98% ± 2.6%. Release profiles in absence and presence of an AMF indicate a transport by diffusion, with a maximum compound release of 31% under the AMF. A sustained and controlled drug release in anticipated from the results, pointing to suitable characteristics of the magnetoliposomes for dual cancer therapy (combined magnetic hyperthermia and chemotherapy).
Probing Nuclear Dipole Moments and Magnetic Shielding Constants Through 3-Helium NMR Spectroscopy
Włodzimierz Makulski
Subject: Chemistry, Physical Chemistry Keywords: nuclear magnetic dipole moment; nuclear magnetic shielding; gas-phase NMR
Multinuclear NMR studies of the gaseous mixtures that involve volatile compounds and 3He atoms are featured in this review. Precise analyses of the 3He and other nuclei resonance frequencies show linear dependences on the gas density. Extrapolation of the gas phase results to the zero-pressure limit gives ν0(3He) and ν0(nX) resonance frequencies of nuclei in a single 3-helium atom and nuclei in molecules at a given temperature. The NMR frequency comparison method provides an approach for determining different nuclear magnetic moments. Application of quantum chemical shielding calculations which include a more complete and careful theoretical treatment allows the shielding of isolated molecules to be achieved with great accuracy and precision. They are used for evaluation of nuclear moments without shielding impact on bare nuclei: 10/11B, 13C, 14N, 17O, 19F, 21Ne, 29Si, 31P, 33S, 35/37Cl, 33S , 83Kr, 129/131Xe, and 183W. On the other hand, new results of nuclear moments were used for reevaluation of absolute nuclear magnetic shielding in molecules under study. Additionally, 3He gas in water solutions of lithium and sodium salts was used for measurements of 6/7Li and 23Na magnetic moments and reevaluation of shielding parameters of Li+ and Na+ water solvated cations. In this paper, guest 3He atoms that play a role in probing the electron density in many host macromolecules are presented as well.
Boundary-Element Analysis of Magnetic Polarization Tensor for Metallic Cylinder
Zhongwei Jin, ganghua qin, haidong fan, ruochen huang, ziqi chen, qian zhao, mingyang lu, zhijie zhang, anthony peyton, wuliang yin
Subject: Keywords: Boundary element method (BEM); magnetic polarization tensor; magnetic induction; dipole approximation
The magnetic polarization tensor has a promising capability of determining the geometry and material properties of metallic samples. In this paper, a novel computation method is proposed to estimate the magnetic polarization tensors for the metallic samples using the boundary element method. In this method, the metallic sample is placed in a uniformly distributed magnetic field. Based on assumptions that the excitation frequency and/or the conductivity of the sample is very high, the metallic sample is regarded as a perfect electrical conductor (PEC). Therefore, the scattered field at a certain distance can be simulated. By utilising the boundary element method, the magnetic polarization tensor can be derived from the simulated scattered field. The theoretical calculation is presented and simulations and experiments have been carried out to validate the proposed method. The results from the simulation are matched with the analytical solution for the case of sphere samples. Moreover, there is a good agreement between the simulation results and the experimental results for the copper cylindrical samples.
Fast, Cheap, and Scalable Magnetic Tracker with an Array of Magnetoresistors
Valerio Biancalana, Roberto Cecchi, Piero Chessa, Giuseppe Bevilacqua, Yordanka Dancheva, Antonio Vigilante
Subject: Physical Sciences, Applied Physics Keywords: Tracking; Magnetic tracker; Magnetoresistor; Magnetic Sensor; Sensor Array; Microcontroller; Eye Motion
We present the hardware of a cheap multi-sensor magnetometric setup, where a relatively large set of magnetic field components is measured in several positions by calibrated magnetoresistive detectors. The setup is developed to map the (inhomogeneous) field generated by a known magnetic source, which is measured and then discerned from the background (homogeneous) geomagnetic field. The data output from this hardware can be successfully and reliably used to retrieve the position and orientation of the magnetic source with respect to the sensor frame, together with the orientation of the frame with respect to the environmental field. Possible applications of the setup are briefly discussed, and a synthetic description of the methods of data elaboration and analysis is provided.
The Correlation between Rotational Gravity and Magnetic Field of Celestial Body
Ying-Qiu Gu
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: Earth magnetic field; celestial magnetic field; magnetic dipole; Clifford algebra; Dirac equation; spin-gravity coupling potential; curved space-time
The magnetic field of the earth plays an important role in the ecosystem, and the magnetic field of celestial bodies is also important in the formation of cosmic large-scale structures, but the origin and evolution of the celestial magnetic field is still an unresolved mystery. Many hypotheses to explain the origin have been proposed, but there are some insurmountable difficulties for each one. At present, the theory widely accepted in scientific society is the dynamo model, it says that, the movement of magnetofluid inside celestial bodies, which can overcome the Ohmic dissipative effect and generate persistent weak electric current and macroscopic magnetic field. However, this model needs an initial seed magnetic field, and the true values of many physical parameters inside the celestial body are difficult to obtain, and there is no stable solution to the large range of fluid motion. These are all difficulties for the dynamo model. Furthermore, it is difficult for the dynamo to explain the correlation between the dipole magnetic field and angular momentum of a celestial body. In this paper, by calculating the interaction between spin of particles and gravity of celestial body according to Clifford algebra, we find that a rotational celestial body provides a field $\Omega^\alpha$ for spins, which is similar to the magnetic field of a dipole, and the spins of charged particles within the celestial body are arranged along the flux line of $\Omega^\alpha$, then a macroscopic magnetic field is induced. The calculation shows that the strength of $\Omega^\alpha$ is proportional to the angular momentum of the celestial body, which explains the correlation between the magnetic intensity and angular momentum. The results of this paper suggest that further study of the effects of internal variables such as density, velocity, pressure and temperature of a celestial body on $\Omega^\alpha$ may provide some new insights into the origin and evolution of celestial magnetic field.
Faraday's Law and Magnetic Induction: Cause and Effect
Paul Kinsler
Subject: Physical Sciences, General & Theoretical Physics Keywords: magnetic induction, Faraday, causality
Faraday's Law of induction is often stated as "a change in magnetic flux causes an EMF"; or, more cautiously, "a change in magnetic flux is associated with an EMF"; It is as well that the more cautious form exists, because the first "causes" form can be shown to be incompatible with the usual expression for EMF. This is not, however, to deny the causality as reasonably inferred from experimental observation ­ it is the equation for Faraday's Law of induction which does not represent the claimed cause-and-effect relationship. Here we investigate a selection of different approaches, trying to see how an explicitly causal mathematical equation, which attempts to encapsulate the "a change in magnetic flux causes ..." idea, might arise.
Optimized Power Pads for Charging ElectricVehicles Based on a New Rectangular Spiral Shape Design
Benalia Nadir, Kouider Laroussi, Benlaloui Idriss, Abdellah Kouzou, Abed-Djebar Bensalah, Ralph Kennel, Mohamed Abdelrahem
Subject: Engineering, Electrical & Electronic Engineering Keywords: Wireless Power Transmission (WPT); Rectangular Spiral; Magnetic Analysis; ANSYS Maxwel; Magnetic Shielding
Optimizing the magnetic coupling of two coils of a dynamic wireless charging power supply for electric vehicles (EVs) is a challenging and crucial task. This article examines three situations of the magnetic coupling between two identical rectangular spiral coils with the same number of turns as a function of both the horizontal (X axis) and vertical (Z axis) alignment. In the first one, the analysis of the magnetic coupling between two copper air coils is presented. However, the obtained coupling coefficient was very low with a high leakage flux which affected the performance of the charging system. In the second case, a straightforward shielding method that involves inserting a magnetic material of the ferrite type is proposed to circumvent the aforementioned problems. Unfortunately, the obtained results show that simple shielding is still only a partial and insufficient solution. In the third situation, an aluminum sheet was consequently placed on the top of the ferrite to provide an adequate shielding structure. Additionally, a 3D analysis of the proper and mutual induction parameters separating the two coils as well as a magnetic field or induction distribution is also performed using the ANSYS Maxwell software. The results highlight the significance of the enhanced structure.
Magnetic Transport in Spin Antiferromagnets for Spintronics Applications
Mohamed Azzouz
Subject: Physical Sciences, Condensed Matter Physics Keywords: duality symmetry; magnetic conductivity; magnetic thermal conductivity; spintronics; spin liquids; quantum antiferromagnets
Had magnetic monopoles been ubiquitous as electrons do, we would have probably had a different form of matter, and power plants based on currents of these magnetic charges would have been a familiar scene of modern technology. Magnetic dipoles do exist however, and in principle one could wonder if we can use them to generate magnetic currents. In the present work, we discuss the issue of generating magnetic currents and magnetic thermal currents in electrically-insulating low-dimensional Heisenberg antiferromagnets by invoking the (broken) electricity-magnetism duality symmetry. The ground state of these materials is a spin-liquid state that can be described well via the Jordan-Wigner fermions, which permit an easy definition of the magnetic particle and thermal currents. The spin-liquid states in these antiferromagnets are either gapless or gapped liquids of spinless fermions whose flow defines a current just as the one defined for electrons in a Fermi liquid. The driving force for the magnetic current is a magnetic field with a gradient along the magnetic conductor. The present work is about claiming that what the experiments in spintronics attempt to do is trying to treat the magnetic degrees of freedoms on the same footing as the electronic ones.
Preprint CASE REPORT | doi:10.20944/preprints201608.0094.v1
Brain Biomarkers of Long-term Outcome of Neonatal Onset Urea Cycle Disorder
Maha Mourad, Johannes Häberle, Matthew Whitehead, Tamar Stricker, Andrea L. Gropman
Subject: Medicine & Pharmacology, Pediatrics Keywords: urea cycle disorder; ornithine transcarbamylase deficiency; magnetic resonance imaging; magnetic resonance spectroscopy
Urea cycle disorders (UCDs) are common inborn errors of metabolism, with an incidence of one in 30,000 births. They are caused by deficiencies in any of six enzymes and two carrier proteins, the most common being Ornithine Transcarbamylase Deficiency (OTCD). OTCD results in impairment to excrete nitrogen, causing toxic buildup of ammonia with resultant encephalopathy. Hyperammonemia (HA) induces the conversion of glutamate to glutamine in the brain. Excess glutamine in the brain causes osmotic changes cerebral edema, changes in astrocyte morphology, and cell death. Acute symptoms of HA include vomiting, hyperventilation, seizures, and irritability. Long-term neurological changes include deficits in working memory and executive function. To date, there are no predictors of prognosis of infants with neonatal onset OTCD outside of plasma ammonia level at presentation and duration of hyperammonemic coma. We provide a comprehensive analysis of a 16-year-old male with neonatal onset of OTCD as an example of how brain biomarkers may be useful to monitor disease course and outcome. This male presented at 8 days post natal with plasma ammonia and glutamine of 677 and 4024 micromol/L and had a missense mutation in Exon 4 (p.R129H). Treatment included protein restriction, sodium benzoate, and citrulline, arginine, and iron. He suffered recurrent acute hyperammonemic episodes despite compliance, triggered by infections or catabolic stressors. We discuss the long-term effects of the hyperammonemic episodes by following MRI based disease biomarkers.
Tuning of Magnetoimpedance Effect and Magnetic Properties of Fe-rich Glass-coated Microwires by Joule Heating.
Alvaro Gonzalez, Valentina Zhukova, Paula Corte-Leon, Alexandr Chizhik, Mihail Ipatov, Juan Maria Blanco, Arcady Zhukov
Subject: Materials Science, General Materials Science Keywords: Magnetic microwires; Magnetic anisotropy; Joule heating, Giant magnetoimpedance, Domain wall propagation, Hysteresis loop.
Influence of Joule heating on magnetic properties, giant magnetoimpedance (GMI) effect and domain wall (DW) dynamics of Fe75B9Si12C4 glass-coated microwires was studied. A remarkable increase in GMI ratio is observed in Joule heated samples. The hysteresis loops of Joule heated samples maintain a rectangular shape, while a slight decrease in coercivity after Joule heating is observed. On the other hand, a modification of MOKE hysteresis loops is observed upon Joule heating. Additionally, DW dynamics improvement after Joule heating is observed. The observed GMI ratio improvement along with the change in MOKE loops and DW dynamics improvement has been discussed considering magnetic anisotropy induced by Oersted magnetic field in the surface layer during Joule heating and the internal stress relaxation. A remarkable GMI ratio im-provement observed in Fe-rich Joule-heated microwires with a rectangular hysteresis loop and fast DW propagation, together with the fact that Fe is a more common and less expensive metal than Co, makes them suitable for use in magnetic sensors.
Theoretical Derivation of Critical Current Density and Critical Magnetic Field Considering Many-Body Interactions of Magnetic Flux Quanta
Shinichi Ishiguri
Subject: Physical Sciences, Condensed Matter Physics Keywords: vortices; vortex physics; critical temperature; magnetic flux quantum; critical current density; critical magnetic field; many-body interaction
To clarify the relationships among critical temperature, critical magnetic field, and critical current density, this paper describes many-body interactions of quantum magnetic fluxes (i.e., vortices) and calculates pinning-related critical current density. All calculations are analytically derived, without numerical or fitting methods. Afteralculating a magnetic flux quantum mass, we theoretically obtain the critical temperature in a many-body interaction scenario (which can be handled by our established method). We also derive the critical magnetic field and inherent critical current density at each critical temperature. Finally, we determine the pinning-related critical current density with self-fields. The relationships between the critical magnetic field and critical temperature, inherent critical current density and critical temperature, and pinning critical current density and temperature were consistent with experimental observations. From the critical current density and critical magnetic field, we clarified the magnetic field transition. It appears that a magnetic flux quantum collapses when the lattice of magnetic flux quanta melts. Our results, combined with our previously published papers, provide a comprehensive understanding of the transition points in high-Tc cuprates.
Chemotherapeutic Drug Functionalized Nanoparticles are Beneficial When Treating Breast Cancer Via Magnetic Hyperthermia
Susann Piehler, Heidi Dähring, Julia Grandke, Julia Göring, Pierre Couleaud, Antonio Aires, Aitziber L. Cortajarena, José Courty, Alfonso Latorre, Álvaro Somoza, Rodolfo Miranda, Ingrid Hilger
Subject: Life Sciences, Biophysics Keywords: magnetic hyperthermia, magnetic nanoparticles (MNP), doxorubicin (DOX), NucAnt (N6L), breast cancer, mouse model
Doxorubicin (DOX) is a frequently used chemotherapeutic drug for breast cancer, but its site specificity and local internalization into tumor cells is rather low. In this paper we conjugated magnetic nanoparticles (MNPs) with DOX and/or a pseudopeptide NucAnt (N6L) as modality to enhance DOX-induced antitumor effects in breast cancer cells (BT474). In this context, we determined cellular uptake of MNP formulations, analyzed cell viability and expression of apoptotic and cell cycle proteins after magnetic hyperthermia (43°C, 1 h) in vivo and in vitro. We have shown that i) the presence of N6L on the surface of DOX-functionalized MNPs increases their internalization into a target cells and potentiates the cytotoxic potential of the anticancer drug, ii) in combination with hyperthermia, DOX functionalized MNPs influence the expression of apoptotic and cell cycle proteins, and also favors tumor regression in vivo. Our data show that intratumoral application of DOX coupled MNPs is able to overcome biological barriers to chemotherapeutic drugs, enabling them to penetrate into the target cells. Combined with hyperthermia these MNPs can be an effective method in enhancing the localised delivery and penetration of DOX into breast cancer cells.
Preliminary Analysis of a Nano Relativistic Motor
Asher Yahalom
Subject: Physical Sciences, General & Theoretical Physics Keywords: Relativity; Nano Technology; Magnetic materials
In a recent paper discussing Newton's third law in the framework of special relativity for charged bodies, it was suggested that one can construct a practical relativistic motor provided high enough charge and current densities are available. As on the macroscopic scale charge density is limited by the phenomena of dielectric breakdown, it was suggested to take advantage of the high charge densities which are available on the microscopic scale. A preliminary analysis of this option denoted "nano relativistic scale" is studied in the current paper.
Nanometers-Thick Ferromagnetic Surface Produced by Laser Cutting of Diamond
Annette Setzer, Pablo D. Esquinazi, Sergei Buga, Milena Georgieva, Tilo Reinert, Tom Venus, Irina Estrela-Lopis, Andrei Ivashenko, Maria Bondarenko, Winfried Böhlmann, Jan Meijer
Subject: Materials Science, Surfaces, Coatings & Films Keywords: Diamond; Magnetic order; Laser treatment
In this work, we demonstrate that cutting diamond crystals with a laser (532 nm wavelength, 0.5 mJ energy, 200 ns pulse duration at 15 kHz) produces a ≲20nm thick surface layer with magnetic order at room temperature. We have measured the magnetic moment with a SQUID magnetometer of six natural and six CVD diamond crystals of different size, nitrogen content and surface orientations. A robust ferromagnetic response at 300 K is observed only for crystals that were cut with the laser along the (100) surface orientation. The magnetic signals are much weaker for the (110) and negligible for the (111) orientations. We attribute the magnetic order to the disordered graphite layer produced by the laser at the diamond surface. The ferromagnetic signal vanished after chemical etching or after moderate temperature annealing. The obtained results indicate that laser treatment of diamond may pave the way to create ferromagnetic spots at its surface.
Baryogenesis in the Desert between Electroweak and Grand Unification Scale
Biping Gong
Subject: Physical Sciences, General & Theoretical Physics Keywords: cosmology; inflation; baryogenesis; magnetic monopole
As the Universe is dominated by of baryons, there must have been a process in early Universe creating such a asymmetry via baryon number violation. However, until recently all the confirmed experimental data indicate that lepton and baryon number are conserved in agreement with Standard Model of quarks and leptons. This paper proposes an alternative path of baryogenesis. Once the over abundant magnetic monopoles predicted by grand unification emerged at universe temperature of $10^{16}$ GeV, then their annihilation should first give rise to photons driving the expansion of the early universe. As the universe temperature dropped to the desert scale of around 10 EeV, departure from thermal equilibrium occurred. Thus the annihilation produced photons give rise to electron-positron pairs, which collide with remnant magnetic monopoles and antimonopoles. The resultant unstable intermediate X and antiX particle become asymmetric, and thereby leading to baryon asymmetry. The excess of antimonopoles corresponding to ten times of mass comparing with that of baryons provides a natural candidate for dark matter. The physics of such a desert regime baryogenesis can be simply characterized by three parameters. The collision predicts a ratio of particle and anti-particle equivalent to that of ultra-high-energy neutrino to their anti-particle, which can be tested by future observations, e.g., the constructing IceCube-Gen2.
A Perspective on Cell Tracking with Magnetic Particle Imaging
Olivia C. Sehl, Julia J. Gevaert, Kierstin P. Melo, Natasha N. Knier, Paula J. Foster
Subject: Keywords: magnetic particle imaging, cell tracking
Magnetic Particle Imaging (MPI) is a new imaging modality that sensitively and specifically detects superparamagnetic iron oxide nanoparticles (SPIONs). Many labs have been developing cellular magnetic resonance imaging (MRI) tools using both SPIONs and fluorine-19 (19F)-based contrast agents for numerous important applications, including tracking of immune and stem cells used for cellular therapies. SPION-based MRI cell tracking has very high sensitivity, but low specificity. SPIONs produce negative contrast in MRI, or signal voids. SPIO is not directly detected by MRI, but indirectly through its relaxation effects on protons, therefore, it is not possible to reliably quantify the local tissue concentration of SPION particles and cell number cannot be determined. 19F based cell tracking uses perfluorocarbons (PFC) to label cells. The number of 19F atoms can be directly measured from 19F MR images and related to cell number. 19F MRI has high specificity, but low sensitivity. MPI cell tracking displays great potential for overcoming the challenges of MRI-based cell tracking allowing for both high cellular sensitivity and high specificity and quantification of SPIO labeled cell number. In this paper we describe nanoparticle and MPI system factors that influence MPI sensitivity and resolution, quantification methods and give our perspective on testing and applying MPI for cell tracking.
Magnetocaloric Effect in Non-Interactive Electrons Systems: ``The Landau Problem'' and Its Extension to Quantum Dot
Oscar A. Negrete, Francisco J. Peña, Juan M. Florez, Patricio Vargas
Subject: Physical Sciences, Condensed Matter Physics Keywords: magnetocaloric effect; magnetic cycle; thermodynamics
In this work, we report the magnetocaloric effect (MCE) in two systems of non-interactive particles, the first corresponds to the Landau problem case and the second, the case of an electron in a quantum dot subjected to a parabolic confinement potential. In the first scenario, we realize that the effect is totally different from what happens when the degeneration of a single electron confined in a magnetic field is not taken into account. In particular, when the degeneracy of the system is negligible, the magnetocaloric effect cools the system, while in the other case, when the degeneracy is strong, the system heats up. For the second case, we study the competition between the characteristic frequency of the potential trap and the cyclotron frequency to find the optimal region that maximizes the ΔT of the magnetocaloric effect, and due to the strong degeneration of this problem, the results are in coherence with those obtained for the Landau problem. Finally, we consider the case of a transition from a normal MCE to an inverse one and back to normal as a function of temperature. This is due to the competition between the diamagnetic and paramagnetic response when the electron spin in the formulation is included.
A Rapid Magnetofluidic Micromixer Using Diluted Ferrofluid
Majid Hejazian, Nam-Trung Nguyen
Subject: Engineering, Mechanical Engineering Keywords: magnetic; microfluidics; mixing; magnetoconvection; ferrofluid
Effective and rapid mixing is essential for various chemical and biological assays. The present work reports a simple and low-cost micromixer based on magnetofluidic actuation. The device takes advantage of magnetoconvective secondary flow, a bulk flow induced by an external magnetic field, for mixing. A paramagnetic stream of diluted ferrofluid and a non-magnetic stream are introduced to a straight microchannel. A permanent magnet placed next to the microchannel induced a non-uniform magnetic field. The magnetic field gradient and the mismatch in magnetic susceptibility between the two streams create a body force, which leads to rapid and efficient mixing. The micromixer reported here could achieve a high throughput and a high mixing efficiency of 90 % in a relatively short microchannel.
A Non-inductive Magnetic Eye-Tracker: From Dipole Tracking to Gaze Retrieval
Valerio Biancalana, Piero Chessa
Subject: Physical Sciences, Applied Physics Keywords: Eye Tracking; Magnetic tracker; Magnetic Sensor; Sensor Array; eye motion; Donders' Law; Listing's law
We analyze the information that can be retrieved from the tracking parameters produced by an innovative wearable eye tracker. The latter is based on a permanent-magnet marked corneal lens and by an array of magnetoresistive detectors that measure the magnetostatic field in several positions in the eye proximity. We demonstrate that, despite missing information due to the axial symmetry of the measured field, physiological constraints or measurement conditions make possible to infer complete eye-pose data. Angular precision and accuracy achieved with the current prototypical device are also assessed and briefly discussed. The results show that the instrumentation considered is suitable as a new, moderately invasive medical diagnostics for the characterization of ocular movements and associated disorders.
Evaluation of Magnetic Parameters and Kinetics of the Magnetic Nanoparticles in High Magnetic Fields
Mark Christopher Arokiaraj, Aleksandr Liubimtcev
Subject: Keywords: Magnetic nanoparticles, High magnetic fields, Electromagnetic finite element analysis, Angiogenesis, Tissue engineering, Halbach array
Background: Multifunctional nanoparticles are known for their wide range of biomedical applications. Controlling the magnetic properties of these nanoparticles is imperative for various applications, including therapeutic angiogenesis. The study was performed to evaluate the magnetic properties and their control mechanisms by the external magnetic field. Methods: A 100nm magnetic nanoparticle was placed in the magnetic field, and parametrically the magnet field strength and distance was evaluated. Various models of magnetic strength and disposition were evaluated. Magnetic flux density, force/weight, and magnetic gradient strength were the parameters evaluated in electromagnetic computational software. Results: The seven-coil method with three centrally placed coils as Halbach array, and each coil with a flux density of 7 Tesla, and with a coil dimension of 20cmx20cm (square model) of each coil showed a good magnetic strength and force/weight parameters in a distance of 15cm from the centrally placed coil. The particles were then evaluated for their motion characteristics in saline. It showed good displacement and acceleration properties. After that, the particles were theoretically assessed in a similar mathematical model after parametrically correcting the drag force. After application of high drag forces, the particles showed adequate motion characteristics. When the particle size was reduced further, the motion characteristics were preserved even with high drag forces. Conclusion: There is potential for a novel method of controlling multifunctional magnetic nanoparticles using high magnetic fields. Further studies are required to evaluate the motion characteristics of these particles in-vivo and invitro.
The Radiofrequency NMR Spectra of Lithium Salts in Water; Reevaluation of Nuclear Magnetic Moments for 6Li and 7Li Nuclei
Subject: Chemistry, Physical Chemistry Keywords: 6Li and 7Li nuclear magnetic moments; NMR liquid-phase studies; nuclear magnetic shielding constants
The LiCl and LiNO3 water solutions in the presence of small amounts of 3-helium have been investigated by means of multinuclear resonance spectroscopy. The resulting concentration dependences of the 3He, 6,7Li+, 14NO3¯ and 35Cl¯ resonance radiofrequencies are reported in the infinite limit. This data along with new theoretical corrections of shielding lithium ions was analyzed by a known NMR relationship method. Consequently, the nuclear magnetic moments of 6Li and 7Li were established against that of the helium-3 dipole moment: μ(6Li)=+0.822046(5)μN and μ(7Li)=+3.256418(20)μN. The new results were shown to be very close to the previously obtained values of the (ABMR) atomic beam magnetic resonance method. This experiment proves that our helium method is well suited for establishing dipole moments from NMR measurements performed in water solutions. This technique is especially valuable when gaseous substances of the needed element are not available. All shielding constants of species present in water solutions are consistent with new nuclear magnetic moments and these taken as a reference. Both techniques – NMR and ABMR – give practically the same results providing that all shielding corrections are properly made.
Using MRI in Emergency Departments; Expensive Choice, But Sometimes the Optimal Means of Evaluation!
Betül Tiryaki Baştuğ
Subject: Medicine & Pharmacology, General Medical Research Keywords: magnetic resonance imaging; emergency departments; utility
Most pathologies in emergency departments(EDs) can be detected with using non-invasive, extremely safe magnetic resonance imaging (MRI). MRI is highly sensitive to abnormality, so when compared to Computed Tomography(CT), a negative MRI far exceeds the value of a negative CT. This was a retrospective cohort study comparing resource utilization between September 2016 and September 2017 in a university hospital ED. Descriptive statistics are presented with frequency, percentage, mean, standard deviation, minimum and maximum values. A chi-square analysis was conducted to examine the relationships. Analyses were conducted using the SPSS 22.0 package program. In the ED, MRI is available 24/7. MRI was performed on 954 (479 female, 475 male) patients. A total of 212 cranial, 604 diffusion, 57 lumbar, 40 cervical, 38 dorsal, two abdominal, and one orbital MRIs were performed. In most groups, the average age was over 40, and the age distribution was similar (p = 0.12). There was no significant sex difference except for lumbar MRI. Lumbar MRI and diffusion MRI groups were admitted to the hospital mostly in the day hours (p = 0.03); in other groups, night and day admissions were almost the same. Neuroimaging takes the majority part of MRI examinations in our ED.
Retro-Fitting Earth-Field Compensation Coils to the Vertical Cryostat GERSEMI in FREIA
Volker Ziemann, Rolf Wedberg, Tord Peterson, Anders Wiren
Subject: Physical Sciences, Applied Physics Keywords: magnetic field compensation; vertical cryostat; FREIA
We describe the design and construction of coils to compensate the earth's magnetic field in the vertical cryostat GERSEMI in the FREIA laboratory at Uppsala University.
External Field-Controlled Ablation: Magnetic Fields
Jovan Maksimovic, Soon Hock Ng, Tomas Katkus, Bruce C. C. Cowie, Saulius Juodkazis
Subject: Physical Sciences, Optics Keywords: ablation; magnetic field; femtosecond laser fabrication
Laser ablation of silicon under an external applied magnetic field with different orientations was investigated in respect to the scanning direction and polarisation of the laser beam, by observation of the ablation patterns and debris deposition. Ultra-short ∼230 fs laser pulses of 1030 nm wavelengths were used in the single and multi-pulse irradiation modes. Ablation with an externally applied magnetic B-field (B ≈ 0.1 T) is shown to strongly affect debris formation. The mechanism of surface plasmon polariton (SPP) wave can explain the ablated periodic patterns observed with alignment along the magnetic field lines.
Liquid Metal Flow under Traveling Magnetic Field: Solidification Simulation and Pulsating Flow Analysis
Evgeniy Shvydkiy, Egbert Baake, Diana Köppen
Subject: Materials Science, Metallurgy Keywords: electromagnetic stirring; forced convection; traveling magnetic field; liquid metal; solidification; numerical analysis; pulsed magnetic field; gallium
Non steady applied magnetic field impact on a liquid metals has good prospects for industry. For a better understanding of heat and mass transfer processes under these circumstances, numerical simulations are needed. A combination of finite elements and volumes methods was used to calculate the flow and solidification of liquid metal under electromagnetic influence. Validation of numerical results was carried out by means of measuring with ultrasound Doppler velocimetry technique, as well as with neutron radiography snapshots of the position and shape of the solid/liquid interface. As a result of the first part of the work, a numerical model of electromagnetic stirring and solidification was developed and validated. This model could be an effective tool for analyzing the electromagnetic stirring during the solidification process. In the second part, the dependences of the velocity pulsation amplitude and the melt velocity maximum value on the magnetic field pulsation frequency are obtained. It was found numerically the ability of the pulsating force action to develop higher values of the liquid metal velocity at a frequency close to the MHD resonance. Obtained characteristics give a more detailed description of the electrically conductive liquid behaviour under action of pulsating traveling magnetic field.
In Vivo Imaging of Local Gene Expression Induced by Magnetic Hyperthermia
Olivier Sandre, Coralie Genevois, Eneko Garaio, Laurent Adumeau, Stéphane Mornet, Franck Couillaud
Subject: Life Sciences, Biotechnology Keywords: magnetic hyperthermia; gene therapies; heat shock protein promoter; in vivo optical imaging; magnetic polymer-coated nanoparticles
The present work aims to demonstrate that colloidal dispersions of magnetic iron oxide nanoparticles stabilized with dextran macromolecules placed in an alternating magnetic field can not only produce heat, but also that these particles could be used in vivo for local and non-invasive deposition of a thermal dose sufficient to trigger thermo-induced gene expression. Iron oxide nanoparticles were first characterized in vitro on a bio-inspired setup, and then they were assayed in vivo using a transgenic mouse strain expressing the luciferase reporter gene under transcriptional control of a thermosensitive promoter. Iron oxide nanoparticles dispersions were applied topically on the mouse skin or injected sub-cutaneously with Matrigel™ to generate so called pseudo tumors. Temperature was monitored continuously with a feedback loop to control the power of the magnetic field generator and to avoid overheating. Thermo-induced luciferase expression was followed by bioluminescence imaging 6 hours after heating. We showed that dextran-coated magnetic iron oxide nanoparticles dispersions were able to induce in vivo mild hyperthermia compatible with thermo-induced gene expression in surrounding tissues and without impairing cell viability. These data open new therapeutic perspectives for using mild magnetic hyperthermia as non-invasive modulation of tumor microenvironment by local thermo-induced gene expression or drug release.
Quantitative MR Markers in Non-Myelopathic Spinal Cord Compression: A Narrative Review
Jan Valošek, Petr Bednařík, Miloš Keřkovský, Petr Hluštík, Josef Bednařík, Alena Svátková
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: non-myelopathic cervical spinal cord compression; degenerative cervical myelopathy; diffusion magnetic resonance imaging; quantitative magnetic resonance imaging
Degenerative spinal cord (SC) compression is a frequent pathological condition with increasing prevalence throughout aging. Initial non-myelopathic cervical SC compression (NMDC) might progress over time into potentially irreversible degenerative cervical myelopathy (DCM). While quantitative MRI (qMRI) techniques demonstrated the ability to depict intrinsic tissue properties, longitudinal in-vivo biomarkers to identify NMDC patients who will eventually develop DCM are still missing. Thus, we aim to review the ability of qMRI techniques (such as diffusion MRI, diffusion tensor imaging (DTI), magnetization transfer (MT) imaging, magnetic resonance spec-troscopy (1H-MRS)) to serve as prognostic markers in NMDC. While DTI in NMDC patients con-sistently detected lower fractional anisotropy and higher mean diffusivity at compressed levels caused by demyelination and axonal injury, MT and 1H-MRS along with advanced and tract-specific diffusion MRI recently revealed microstructural alterations also rostrally pointing to Wallerian degeneration. Recent studies also disclosed significant relationship between micro-structural damage and functional deficits, assessed by qMRI and electrophysiology, respectively. Thus, tract-specific qMRI in combination with electrophysiology critically extend our under-standing of the underlying pathophysiology of degenerative SC compression and may provide predictive markers of DCM development for accurate patient management. However, the prog-nostic value must be validated in longitudinal studies.
Measuring the Magnetic Flux Density with Flux Loops and Hall Probes in the CMS Magnet Flux Return Yoke
Benoit Curé, Vyacheslav Klyukhin, Nicola Amapane, Austin Ball, Andrea Gaddi, Hubert Gerwig, Alain Hervé, Richard Loveless, Martijn Mulders
Subject: Physical Sciences, Nuclear & High Energy Physics Keywords: electromagnetic modeling; flux loops; Hall effect devices; magnetic field measurement; magnetic flux density; measurement techniques; superconducting magnets
The direct measurements of the magnetic flux density in steel blocks within Compact Muon Solenoid (CMS) magnet yoke are performed with 22 flux loops installed in selected regions of the yoke. The 10,000-ton CMS magnet flux return yoke encloses a 4 T superconducting solenoid with a 6-m-diameter by 12.5-m-length free bore and consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end. The yoke steel blocks, mostly up to 620 mm thick, serve as the absorber plates of the muon detection system. A TOSCA 3-D model of the CMS magnet has been developed to describe the magnetic field everywhere outside of the tracking volume which was measured with a field-mapping machine. In the present study, for the first time, the reliable reconstruction of the magnetic flux density in the steel blocks of the yoke is performed using the CMS magnet standard discharges from the operational magnet current of 18.164 kA. To provide this reconstruction, the voltages induced in the flux loops (with amplitudes of 20–250 mV) have been measured with six 16-bit DAQ modules and integrated offline over time. The results of the flux loop measurements during three magnet ramp downs are presented and discussed.
Carbon Dots/Iron Oxide Nanoparticles With Tuneable Composition and Properties
Joanna D Stachowska, Monika B Gamża, Claire Mellor, Ella N Gibbons, Marta J Krysmann, Antonios Kelarakis, Elżbieta Gumieniczek-Chłopek, Tomasz Strączek, Czesław Kapusta, Anna Szwajca
Subject: Materials Science, Nanotechnology Keywords: magnetization; photoluminescence; carbon dots; magnetic nanoparticles; antimicrobial
We present a simple strategy to generate a family of carbon dot/iron oxide nanoparticles (C/Fe-NPs) that relies on the thermal decomposition of iron (III) acetylacetonate in the presence of a highly fluorescent carbon-rich precursor, while polyethylene glycol serves as the passivation agent. By varying the molar ratio of the reactants, a series of C/Fe-NPs have been synthesized with tuneable elemental composition in terms of C, H, O, N, Fe. The quantum yield is enhanced from 6% to 9% as the carbon content increases from 27% to 36%, while the room temperature saturation magnetization is improved from 4.1 emu/g to 17.7 emu/g as the iron content is enriched from 17 to 31%. In addition, the C/Fe-NPs show excellent antimicrobial properties, minimal cytotoxicity and demonstrate promising bioimaging capabilities, thus showing great potential for the development of advanced diagnostic tools.
Magnetic Resonance for Differential Diagnosis of Left Ventricular Hypertrophy: Diagnostic and Prognostic Implications
Giovanni Donato Aquaro, Elisabetta Corsi, Giancarlo Todiere, Chrysanthos Grigoratos, Andrea Barison, Valerio Barra, Gianluca di Bella, Michele Emdin, Fabrizio Ricci, Alessandro Pingitore
Subject: Medicine & Pharmacology, Cardiology Keywords: Left ventricular hypertrophy; Echocardiography; Magnetic Resonance; Prognosis
Background: Left ventricular hypertrophy (LVH) may be due to different causes, ranging from benign secondary forms to severe cardiomyopathies. Transthoracic Echocardiography (TTE) and ECG are the first level examination for LVH diagnosis. Cardiac magnetic resonance (CMR) defines accurately LVH type, extent and severity. Objectives: to evaluate the diagnostic and prognostic role of CMR in patients with TTE and/or ECG evidence of LVH. Methods: We performed CMR in 300 consecutive patients with echocardiographic and/or ECG signs of LVH. Results: Overall, 275 patients had TTE evidence of LVH with initial suspicion of hypertrophic cardiomyopathy (HCM) in 132 (44%), cardiac amyloidosis in 41 (14%), hypertensive LVH in 48 (16%), aortic stenosis in 4 (1%), undetermined LVH in 50(16%). The initial echocardiographic diagnostic suspicion of LVH was confirmed in 172 patients (57.3%) and changed in 128 patients (42.7%, p<0.0001): the diagnosis of HCM increased from 44% to 71% of patients; hypertensive and undetermined LVH decreased significantly (respectively to 4% and 5%). CMR allowed a diagnosis in 41 out of 50 (82%) with undetermined LVH at TTE. CMR also identified HCM in 17 out of 25 patients with apparently normal echo but with ECG criteria for LVH. Finally, the reclassification of the diagnosis by CMR was associated with a change of survival risk of patients: after CMR reclassification no events occurred in patients with undetermined or hypertensive LVH. Conclusions: CMR changed echocardiographic suspicion in almost half of patients with LVH. In the subgroup of patient with abnormal ECG, CMR identified LVH (particularly HCM) in 80% of patients. This study highlights the indication of CMR to better characterize the type, extent and severity of LVH detected at echocardiography and suspected with ECG.
Magnetic Field Alignment, a Perspective in the Engineering of Collagen-Silica Composite Biomaterials
Nicolas Debons, Kenta Matsumoto, Noriyuki Hirota, Thibaud Coradin, Toshiyuki Ikoma, Carole Aimé
Subject: Materials Science, Biomaterials Keywords: bionanocomposites; collagen; high magnetic field; silica particles
Major progress in the field of regenerative medicine are expected from the design of artificial scaffolds that mimic both the structural and functional properties of the ECM. The bionanocomposites approach is particularly well fitted to meet this challenge as it can combine ECM-based matrices and colloidal carriers of biological cues that regulate cell behavior. Here we have prepared bionanocomposites under high magnetic field from Tilapia fish scale collagen and multifunctional silica nanoparticles (SiNPs). We show that scaffolding cues (collagen), multiple display of signaling peptides (SiNPs) and control over the global structuration (magnetic field) can be combined into a unique bionanocomposite for the engineering of biomaterials with improved cell performances.
Electronic, Magnetic and Optical Properties of XScO3 (X=Mo, W) Perovskites
Amall Ramanathan, Jamil Khalifeh
Subject: Keywords: DFT-mBJ; magnetic moments; optical conductivity; perovskites
Density Functional Theory (DFT) full potential linearized augmented plane wave (FP-LAPW) method with the Modified Becke-Johnson (mBJ) approximation is used to perform spin polarised calculations of the transition metal perovskites MoScO3 and WScO3. Both depict half metallic behaviour with semiconducting and metallic in the minority and majority spins respectively. MoScO3 and WScO3 have indirect R− Γ band gaps in the minority spin channels of 3.61 and 3.82eV respectively. Moreover, they both show substantial magnetic moments of 2.99μB. In addition, we calculate the dielectric function, optical conductivity and the optical constants, namely, the refractive index, the reflectivity, the extinction and absorption coefficients.
Measurements of Thickness for Metallic Plates with Co-Axial Holes Using a Novel Analytical Method with the Modified Integration Range
Wuliang Yin, Ruochen Huang, Mingyang Lu, Zhijie Zhang, Anthony Peyton
Subject: Engineering, Automotive Engineering Keywords: Magnetic induction; eddy current testing; thickness measurement.
The existence of the hole on a plate affects the calculation of eddy current problems. Consequently, the accuracy for the prediction of the material properties decreases if the effect of the hole is not taken into account. In this paper, a novel analytical method based on the modified integration range is proposed which can address the presence of the hole. Due to the presence of the hole, the conventional Dodd-Deeds analytical solution cannot be used to calculate the inductance change. Therefore, a revised upper integration limit is introduced to replace the original limit -- ∞ when using the co-axially air-core electromagnetic sensor. With the presence of the hole, the magnitude of the received signal reduces, and the peak frequency feature changes. The analytical method is validated by measured and numerical simulation results. It is found that the upper limit is related to the radius of the open hole. With the new technique, the thickness of sample plates with holes can be estimated based on the peak frequency feature.
Design and Construction of Magnetic Coils for Quantum Magnetism Experiments
Graciana Puentes
Subject: Physical Sciences, Atomic & Molecular Physics Keywords: Cold atoms, Zeeman slower, quadrupole magnetic trap
We report on the design and construction of a spin-flip Zeeman slower, quadrupole magnetic trap, and Feshbach fields for a new machine for ultra-cold Li-7. The small mass of the Li-7 atom, and the tight lattice spacing, will enable us to achieve a 100-fold increase in tuneling rates over comparable Rb-87 optical lattice emulator experiments. These improvements should enable to access new regimes in quantum magnetic phase transitions and spin dynamics.
Magnetic Otto Engine for an Electron in a Quantum Dot: Classical and Quantum Approach
Francisco J. Peña, Oscar Negrete, Gabriel Alvarado Barrios, David Zambrano, Alejandro González, Alvaro S. Nuñez, Pedro A. Orellana, Patricio Vargas
Subject: Physical Sciences, Condensed Matter Physics Keywords: magnetic cycle; quantum otto cycle; quantum thermodynamics
We study the performance of a classical and quantum magnetic Otto cycle with a quantum dot as a working substance using the Fock-Darwin model with the inclusion of the Zeeman interaction. Modulating an external/perpendicular magnetic field, we found in the classical approach an oscillating behavior in the total work that is not perceptible under the quantum formulation. Also, we compare the work and efficiency of this system for different regions of the Entropy, $S(T,B)$, diagram where we found that the quantum version of this engine always shows a reduced performance in comparison to his classical counterpart.
Nano-Magnetic Fe3O4/TiO2 Composite : An Efficient Photocatalyst for 2,4 -Dichlorophenol Degradation Under Visible Light
Mona Mehdipoor, Gh. Khayati, A. Ebrahimian Pirbazari
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Nano-Magnetic; TiO2; Fe3O4; Degradation; 2,4-Dicholorophenol
In this work, pure TiO2 and nano-magnetic of Fe3O4/TiO2 were synthesized for degradation of 2,4-dichlorophenol (2, 4-DCP) as an organic pollutant. A range of analytical techniques including XRD, DRS, FESEM, and VSM were employed to reveal the crystal structure, morphology and property of the nanocomposite. The XRD results showed the prepared samples including 100% anatase phase. We obtained the band gap energy 2.9 and 2.8 eV for pure TiO2 and Fe3O4/TiO2 respectively. VSM results demonstrate that easy, fast separation and redispersion of Fe3O4/TiO2 sample can be realized. We obtained 62% and 31% degradation of 2,4-DCP in the presence of Fe3O4/TiO2 and pure TiO2 under visible light respectively.
Properties of Ferrite Garnet (Bi, Lu, Y)3(Fe, Ga)5O12 Thin Film Materials Prepared by RF Magnetron Sputtering
Mohammad Nur E Alam, Mikhail Vasiliev, Vladimir Belotelov, Kamal Alameh
Subject: Physical Sciences, Other Keywords: magneto-optics; magnetic thin films; optical constants
This work is devoted to physical vapor deposition synthesis, and characterisation of bismuth and lutetium-substituted ferrite-garnet thin-film materials for magneto-optic (MO) applications. The properties of garnet thin films sputtered using a target of nominal composition type Bi0.9Lu1.85Y0.25Fe4.0Ga1O12 are studied. By measuring the optical transmission spectra at room temperature, the optical constants and the accurate film thicknesses can be evaluated using Swanepoel's envelope method. The refractive index data are found to be matching very closely to these derived from Cauchy's dispersion formula for the entire spectral range between 300-2500 nm. The optical absorption coefficient and the extinction coefficient data are studied for both the as-deposited and annealed garnet thin-film samples. A new approach is applied for accurately deriving the optical constants data simultaneously with the physical layer thickness, using a combination approach employing custom-built spectrum-fitting software in conjunction with Swanepoel's envelope method. MO properties, such as specific Faraday rotation, MO figure of merit and MO swing factor are also investigated for several annealed garnet-phase films.
Magnetic Engine for the Single-Particle Landau Problem
Francisco J. Peña, Alejandro González, A.S. Nunez, Pedro A. Orellana, René G. Rojas, P. Vargas
Subject: Physical Sciences, Condensed Matter Physics Keywords: quantum thermodynamics; degeneracy effects; magnetic quantum engine
We study the effect of the degeneracy factor in the energy levels of the well-known Landau problem for a magnetic engine. The scheme of the cycle is composed of two adiabatic processes and two isomagnetic processes driven by a quasi-static modulation of external magnetic field intensity. We derive the analytical expression of the relation between the magnetic field and temperature along the adiabatic process and, in particular, reproduce the expression for the efficiency as a function of the compression ratio.
Data Driven Analytical Modeling of Power Transformers
Jyrki Penttonen, Matti Lehtonen
Subject: Engineering, Electrical & Electronic Engineering Keywords: power transformer; coupled inductor; electro-magnetic modeling
In power systems there are complex transformer structures, whose accurate analysis is not possible using the techniques available today. This paper presents a systematic data driven analysis method for coupled inductors of arbitrary complexity. The method first establishes a winding matrix N mapping the windings to the limbs of the transformer. A permeance matrix P is created from the reluctance network of the magnetic core. A generalized inductance matrix L mapping currents in the transformer windings to the induced voltages is generated based on the winding (N) and permeance (P) matrices. The inductance matrix representation of a coupled inductor is then transformed to an admittance matrix, which can be integrated to the nodal analysis of the electrical circuit surrounding the coupled inductor. The method presented is validated by simulations with real transformer structures using electromagnetic transient program (EMTP/ATP).
On the Non-Thermal Energy Content of Cosmic Structures
Franco Vazza, Denis Wittor, Marcus Brueggen, Claudio Gheller
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: Galaxy clusters; cosmic rays; magnetic fields; turbulence
1) Background: the budget of non-thermal energy in galaxy clusters is not well constrained, owing to the observational and theoretical difficulties in studying these diluted plasmas on large scales. 2) Method: we use recent cosmological simulations with complex physics in order to connect the emergence of non-thermal energy to the underlying evolution of gas and dark matter. 3) Results: the impact of non-thermal energy (e.g. cosmic rays, magnetic fields and turbulent motions) is found to increase in the outer region of galaxy clusters. Within numerical and theoretical uncertainties, turbulent motions dominate the budget of non-thermal energy in most of the cosmic volume. 4) Conclusion: assessing the distribution non-thermal energy in galaxy clusters is crucial to perform high-precision cosmology in the future. Constraining the level of non-thermal energy in cluster outskirts will improve our understanding of the acceleration of relativistic particles by cosmic shocks and of the origin of extragalactic magnetic fields.
Peculiar Magnetic Features and Superconductivity in Sulfur Doped Amorphous Carbon
Israel Felner
Subject: Chemistry, Other Keywords: amorphous carbon; sulfur; superconductivity; peculiar magnetic behavior
We report on magnetic studies of inhomogeneous commercial and synthesized amorphous carbon (a-C) and a-C doped with sulfur (a-CS) powders which exhibit (i) peculiar magnetic behavior and (ii) traces of two superconducting (SC) phase ~ Tc=33 and at 65 K. (i) The temperature dependence of zero-field-cooled (ZFC) curves measured up to room temperature show a well distinguish elusive peaks around 50-80 K, their origin is not yet known. These peaks are totally washed-out in the second ZFC sweeps and in the FC branches as well. As a result, in the vicinity of the peaks, the FC curves lie below the ZFC peaks (FC<ZFC), a phenomenon which is rarely observed. These magnetic anomalies are intrinsic properties of a-C and a-CS materials (ii) SC was observed in three different a-C sources: (a) The commercial a-C powder contains 0.21% of sulfur and it is suggested that two different a-CS phases (at 33 and 65 K) are the origin of the two SC states observed. The compositions of these two phases are not yet unknown. The small SC volume fractions of the 33 K phase can be enhanced by a solid reaction with additional sulfur at 250 ºC. (b) The synthesized a-C powder (obtained from decomposition of sucrose) is not SC. However, when mixed with sulfur and heated at 400 ºC under a protective atmosphere, the a-CS powder obtained also show traces of a SC phase at TC= 42 K. (c)The same occurs in a-C thin films. The as-grown films are not SC but a SC phase at Tc = 34 K emerges after the films were reacted with sulfur at elevated temperatures. It is concluded therefore, that all SC phases observed are due to different unknown a-CS phases. Since the a-C and a-CS powders possess SC and magnetic states, we believe that these powders resemble the high TC curates and Fe-As based systems in which the SC and the magnetic states are closed related to each other.
A Miniature Permanent Magnet Assembly with Localized and Uniform Field with an Application to Optical Pumping of Helium
Garnet Cameron, Jonathan Cuevas, Jeffrey Pound Jr., David Shiner
Subject: Physical Sciences, Atomic & Molecular Physics Keywords: optical pumping; annular permanent magnet; miniature magnet; laser orbital angular mo-mentum; collimated magnetic field; fringe magnetic field
Atomic state preparation can benefit from a compact and uniform magnetic field source. Simulations and experimental measurements have been used to design, build, and test such a source as shown by optical pumping of atomic Helium. This source is a 9.5 mm (3/8") OD x 6.7 mm (1/4") ID x 9.5 mm (3/8") long, NdFeB-N42 assembly of 1.6 mm (1/16") thick customized annular magnets. It has octopole decay with a residual dipole far field from imperfect dipole cancelations. It has greater than 50% clear aperture with uniform and collimated magnetic field consistent with the prediction of several models. Octopole roll-off localizes the field minimizing the need for shielding in applications. The device is applied to a high precision 3,4He laser spectroscopy experiment using σ+ or σ- optical pumping currently resulting in a measured 99.3% preparation efficiency and in accordance with a rate-equation model.
The Influence of Selected Soil Parameters Modified With Sewage Sludge and Fly Ash Fertilization on the Total Number of Bacteria (TNB) and Bradyrhizobium Species at Soybean Agroecosystem
Izabella Pisarek, Katarzyna Grata
Subject: Biology, Agricultural Sciences & Agronomy Keywords: soybean agroecosystem; Bradyrhizobium species; magnetic susceptibility; humic substances.
In this study, the influence of the environment on soil conditions, e.g. heavy metals and soil magnetic susceptibility, on the total number of bacteria and the species of Bradyrhizobium in the field cultivation of the soybean variety Lissabon, the seeds of which had been inoculated with HiStick®Soy, were evaluated. Field experiments were carried out with the random plot method on the Cambisol with a texture of silt loam. The experiment consisted of 24 objects in six combinations and four replications using sewage sludge and fly ash. In the soil samples, the total number of bacteria and the number of the species of Bradyrhizobium were determined using the culture-plate method. The total content of heavy metals (Cu, Zn, Cd, Ni, Pb, Cr, Hg, Fe) in the analyzed objects, compared to the limit values, allowed them to be classified as uncontaminated soils despite the application of sewage sludge and fly ash according to the experimental scheme, showed a significant difference between them. The study of the magnetic parameter χ indicated a significant differentiation between objects from 34.0 to 65.8 × 10-8m3kg-1. High correlation coefficients between χ and Fe (r = 0.789), Zn (r = 0.653), Cr (r = 0.617) and TOC (r = 0.949) indicated that the source of these elements was external organic matter. Biological tests (total content of bacteria and species of Bradyrhizobium) in different experimental variants indicated significant relationships between them and showed the resistance of the microbial community in the field cultivation of Lissabon soybean to heavy metal contamination from sewage sludge and fly ash.
Photocatalytically Active Supramolecular Organic-inorganic Magnetic Composites as Efficient Route to Remove β-lactam Antibiotics from Water
Sabina Gabriela Ion, Octavian D. Pavel, Nicolae Guzo, Madalina Tudorache, Simona M. Coman, Vasile I. Parvulescu, Bogdan Cojocaru, Elisabeth E. Jacobsen
Subject: Chemistry, Applied Chemistry Keywords: layered double hydroxides; magnetic nanoparticles; phthalocyanines; antibiotics removal
Considerable efforts have been made in recent years to identify an optimal treatment method for the removal of antibiotics from wastewaters. A series of supramolecular organic-inorganic magnetic composites containing Zn-modified MgAl LDHs and Cu-phthalocyanine as photosensitizer have been prepared with the scope to β-lactam antibiotics removal from aqueous solutions. The characterization of these materials confirmed the anchorage of Cu-phthalocyanine onto the edges of the LDH lamellae, with a negligible part inserted in the interlayer space. The removal of β-lactam antibiotics occurred via a concerted adsorption and photocatalytic degradation. The efficiency of the composites was depending on i) the LDH: magnetic nanoparticle (MP) ratio, that is strongly correlated to the textural properties of the catalysts, and ii) the phthalocyanine loading in the final composite. A maximum of the efficiency was achieved with a removal of ~93% of antibiotics after 2h of reaction.
Was Cosmic Inflation Driven by Quantum Field or Its Product ?
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: magnetic monopole; inflation, scalar field; Grand Unification theories
Inflationary model provides a conceptual explanation of the horizon problem, the flatness problem and may also suppress the over abundant magnetic monopoles predicted by Grand Unified Theories. Although various inflationary models have been proposed since 1981, difficulties like fine tuning is not only unsolved but also becomes severer in confrontation with data of Planck Satellite. This paper proposes an alternative model of inflation: the spontaneous symmetry breaking phase transition at early universe is only responsible for the production of magnetic monopoles expected by Grand Unified Theories; it is the subsequent energy release of monopole annihilation that drives the inflation. As a result, the early universe underwent a free expansion with a heat source originating in the annihilation, which expects a smooth, plateau-like potential consistent with the observational data. Beside interpreting a number of long standing inflationary problems, the new scenario predicts a significant increase of entropy during the inflation, and tends to produce large scale structures exceed scale of 300 million light-years correlated with a CMB smoothen and flatten by a simple dynamical mechanism.
Design of a 9.4 T Superconducting Magnet for 400 MHz Nuclear Magnetic Resonance
Yong Ren, Da Li, Yuquan Chen
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Magnetic field homogeneity; NMR coil; Superconducting magnet; Stress
A 9.4 T/400 MHz superconducting magnet with a warm bore of 60 mm is being designed. The 400 MHz NMR magnet is composed of 9 coaxial coils to generate a central field of 9.4 T. The magnetic field homogeneity is better than 4 ppm for 50 mm diameter spherical volume (DSV) and better than 1 ppb for 5 mm DSV. Three types of NbTi strands were used to reduce the cost of the superconducting materials. A preload with 80 MPa was exerted on the superconducting coils and over-banding with stainless steel was adopted to release the stress from the electromagnetic forces. The magnet will be operated in persistent mode with superconducting joints to reduce the field decay. The pulse tube cryocooler with a cooling capacity of 1 W at 4.2 K can be used to reduce the liquid helium evaporation and vibration during operation. The magnet will be equipped with Bi2223/AgAu HTS current leads to reduce the heat losses. In this paper, the design of the 9.4 T NMR superconducting coils, electromagnetic field calculations, and stress analysis of the superconducting coils were presented.
The Impact of the Quark's Monopole Properties on the Unification of the Fundamental Physical Forces
Engel Roza
Subject: Physical Sciences, Particle & Field Physics Keywords: Grand Unification; Magnetic Monopole; Pseudo-tachyon; Higgs Field
It is shown that the four fundamental physical forces, i.e. weak interaction, strong interaction, electromagnetism and gravity, all have their origin in the quark as the single true elementary particle.This requires conceiving the quark as a Dirac particle in a pseudo-tachyon mode, which possesses two real dipole moments: the common one associated with its angular momentum and a second one that is polarisable in a scalar field. This Dirac particle carries a regular charge magnetic monopole without Dirac's string, theorized by Comay. The boson carrier of its field of energy is the gluon showing an exponential decay of its spatial range because of the influence of an omni-present energetic background field, known as the Higgs field, in this article interpreted as the Lambda in Einstein's Field Equation.
Disconnect between Published AC Magnetic Susceptibility of a Room Temperature Superconductor and Measured Raw Data
Jorge E Hirsch
Subject: Physical Sciences, Condensed Matter Physics Keywords: room temperature superconductivity; magnetic susceptibility; diamagnetism; raw data
In ref. [1], we pointed out that certain anomalies observed in the published data for ac magnetic susceptibility of a room temperature superconductor reported in Nature 586, 373 (2020) [2] would be cleared up once the measured raw data were made available. Part of the measured raw data were recently posted in arXiv:2111.15017 [3]. Here we report the results of our analysis of these raw data and our conclusion that they are incompatible with the published data. Implications of these results to the claim that the material is a room temperature superconductor are discussed.
Incompatibility of Published ac Magnetic Susceptibility of a Room Temperature Superconductor with Measured Raw Data
J. E. Hirsch
Subject: Physical Sciences, Condensed Matter Physics Keywords: hydride superconductor; room temperature superconductor; pressure; diamond anvil cell; ac magnetic susceptibility; raw data; background signal; random noise
Room temperature superconductivity has recently been reported for a carbonaceous sulfur hydride (CSH) under high pressure by Snider et al [1]. The paper reports sharp drops in magnetic susceptibility as a function of temperature for five different pressures, that are interpreted as signaling a superconducting transition. Here I question the validity and faithfulness of the magnetic susceptibility data presented in the paper by comparison with the measured raw data reported by two of the authors of ref. [2]. This invalidates the assertion of the paper [1] that the susceptibility measurements support the case for superconductivity in this compound.
How Prenatal Exposures Shape the Infant Brain: Insights from Infant Neuroimaging Studies
Alexander Dufford, Marisa Spann, Dustin Scheinost
Subject: Behavioral Sciences, Applied Psychology Keywords: perinatal; maternal; brain development; neurodevelopment; magnetic resonance imaging
Brain development during the prenatal period is rapid and unparalleled by any other time during development. Biological systems undergoing rapid development are at higher risk for disorganizing influences. Therefore, certain prenatal exposures impact brain development, increasing risk for negative neurodevelopmental outcome. While prenatal exposures have been associated with cognitive and behavioral outcomes later in life, the underlying macroscopic brain pathways remain unclear. Here, we review studies investigating the association between prenatal exposures and infant brain development focusing on prenatal exposures via maternal physical health factors, maternal mental health factors, and maternal drug and medication use. Further, we discuss the need for studies to consider multiple prenatal exposures in parallel and suggest future directions for this body of research.
An Uniform Model for Dark Matter and Dark Energy
George N. Izmaïlov
Subject: Physical Sciences, Acoustics Keywords: Dark Matter; Dark Energy; magnetic moment; SQUID; magnetostrictor
In this paper, after reviewing some of the most important concepts about Dark Matter and methods of its registration, in particular by using SQUIDs, a toy uniform model for Dark Matter and Dark Energy is proposed. In the frame of the model Dark Matter particles is interpreted as an excitation of Dark Energy field. The devices based on SQUID, in particular the SQUID-paramagnetic absorber and the SQUID-magnetostrictor systems, both suitable for investigations of above problems, are considered. Estimates, is carried out within this model, indicate the possibility of experimental detection of the "ether wind" pressure, created by the non-corpuscular incoming flow, corresponding to the galactic orbital motion of the Earth.
The Advancement in Magnetic Nanoparticles for the Diagnosis of Lung Cancer and Its Monitoring
Ayushi Rastogi, Fanindra Pandey, Pankaj Kumar Tripathi, Rajiv Manohar, Shri Singh
Subject: Physical Sciences, Acoustics Keywords: Lung Cancer; Magnetic nanoparticles; Detection and monitoring; Theranostics
There are numerous challenges involved in the diagnosis and treatment of lung cancer. Globally, majority of people suffers from cancerous disease involving throat cancer, lung cancer, stomach cancer, cancerous brain tumor. Among these the most common ones is the lung cancer or lung carcinoma. The leading cause of the lung cancer is the smoking. Around 80% to 90% of deaths are caused due to Non-small cell lung cancer (NSCLC). The inadequate diagnostic techniques and low chances for the survival of lung cancer patients results from the lack of an early prognosis and incompetency in traditional therapies. However, such challenges involved in the prognosis and treatment of lung cancer are on decline with the progression in magnetic nanoparticle (MNP) technology. Many break-through discoveries and inventions have been made in the field of cancer therapy by using magnetic nanoparticles. The implication of nanotechnology has led to the recent advancement in nanomedicine field. This has encouraged the improvement in different therapeutic and diagnosis strategies employing nanotechnology. The generation of immense technological benefits for nanoparticles systems has been accredited to its remarkable nanoscale physico-chemical properties. This in turns provides the early detection of lung cancer and active drugs delivery for an improved theranostics strategy. The present review provides a general idea of the current progression in the therapeutic and prognosis purpose of magnetic nanoparticles. Further, we disclose the development in the lung cancer theranostics by functionalization of magnetic nanoparticles. The established importance of magnetic nanoparticles in the theranostics centers for lung cancer has been revealed in this paper. The challenges existing in the theranostics of lung cancer are addressed through the functioning of magnetic nanoparticles in the process.
Magnetic/Polyetherimide-Acrylonitrile Composite Nanofibers for Nickel Ions Removal from Aqueous Solution
Muhammaed O Aijaz, Mohammed R Karim, Hamad F. Alharbi, Nabeel H. Alharthi, Fahad Al-Mubaddel
Subject: Materials Science, Biomaterials Keywords: Polyetherimide; polyacrylonitrile; nanofiber membranes; magnetic nanoparticles; nickel ions
Within the study, magnetic/polyetherimide-acrylonitrile composite nanofibers membrane with effective adsorption of nickel ions in aqueous solution were established, through a simple electrospinning method. Iron oxide nanoparticles were stirred and ultrasonically dispersed into polyetherimide-acrylonitrile solution for homogenous suspension. Afterwards, the polyetherimide-acrylonitrile solution with uniform suspension of iron nanoparticles was used in electrospinning machine to produce uniform and smooth nanofibers composite membrane. The confirmation of nanoparticles incorporation into polymeric membrane were characterized by SEM, EDX, FTIR, XRD and nanoparticles aqueous stability through leach out test. The high adsorption capability of the composite membranes on nickel ions was mainly attributed to the combination of magnetic nanoparticles, polyetherimide-acrylonitrile matrix and nano-sized structure of membrane. Membrane containing magnetic nanoparticles demonstrate the maximum adsorption capabilities (102 mg/g) for nickel ions from aqueous solution. Different kinetics and isotherm models were applied to understand the adsorption behavior during adsorption process, amongst them pseudo second order kinetic and Langmuir isotherm model were well fitted. Additionally, EDX, FTIR and XRD results confirmed the presence of nickel ions onto membrane after adsorption process. Polyetherimide-acrylonitrile composite nanofibers membranes containing magnetic nanoparticles may use as an environmentally-friendly and non-toxic adsorbent for the removal of nickel ions in aqueous medium due to its ease of preparation, easy to use and stability in aqueous medium by retaining the nanoparticles inside the nanofibers membranes.
Endometriosis and the Urinary Tract: from Diagnosis to Surgical Treatment
Mathew Leonardi, Mercedes Espada, Rosanne Kho, Javier Magrina, Anne-Elodie Millischer, Luca Savelli, George Condous
Subject: Medicine & Pharmacology, Obstetrics & Gynaecology Keywords: Endometriosis; ureter; bladder; ultrasound; magnetic resonance imaging; hydroureter.
Abstract We aim to describe the diagnosis and surgical management of urinary tract endometriosis (UTE). We detail current diagnostic tools including advanced transvaginal ultrasound, magnetic resonance imaging, and surgical diagnostic tools such as cystourethroscopy. While discussing surgical treatment options, we emphasize the importance of an interdisciplinary team, for complex cases that involve the urinary tract. While bladder DE is more straightforward in its surgical treatment, ureteral DE requires a high level of surgical skill. Specialists should be aware of the important entity of UTE due to the serious health implications for women. When UTE exists, it is important to work within a interdisciplinary radiological and surgical team.
Realization of Maxwell's Hypothesis An Experiment of Heat-Electric Conversion in Contradiction to the Kelvin Statement
Xinyong Fu, Zitao Fu
Subject: Physical Sciences, General & Theoretical Physics Keywords: Maxwell's demon; magnetic demon; entropy decrease; entropy elimination
In a vacuum tube two identical and parallel Ag-O-Cs emitters A and B (work function 0.8eV) ceaselessly emit thermal electrons at room temperature. The thermal electrons are controlled by a static uniform magnetic field so that the number of electrons migrate from A to B exceeds the one from B to A (or vice versa). The net migration of thermal electrons from A to B quickly results in a charge distribution of A charged positively and B negatively, and a potential difference between A and B emerges, enabling a continuous output current and a stable power to an external load (e.g., a resistor). Thus, the tube cools down (slightly). The (slightly) cooled tube extracts heat from ambient air, and all the heat is converted into electric energy without other effect. We believe the experiment is in contradiction to the Kelvin statement of the second law.
Inflation of Universe by Nonlinear Electrodynamics
Sergey Kruglov
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: Nonlinear electrodynamics; inflation; causality; unitarity; stochastic magnetic fields
Nonlinear electrodynamics with two dimensional parameters is studied. The range of electromagnetic fields when principles of causality, unitarity and the classical stability hold are obtained. A singularity of the electric field at the center of charges is absent within our model and there are corrections to the Coulomb law as $r\rightarrow\infty$. The universe inflation takes place in the background of stochastic magnetic fields. The second stage of the universe evolution is the radiation era so that the graceful exit exists. We estimated the spectral index, the tensor-to-scalar ratio, and the running of the spectral index that are in an approximate agreement with the PLANK and WMAP data.
The First Application of 1H NMR Spectroscopy for the Assessment of the Authenticity of Perfumes
Grzegorz Ciepielowski, Barbara Pacholczyk-Sienicka, Łukasz Albrecht
Subject: Chemistry, Analytical Chemistry Keywords: authentication of perfume, flavours, nuclear magnetic resonance, PCA
The industry of the counterfeit goods is one of the largest underground business in the world and it is rapidly growing. Counterfeits can lead not only to loss of profit for honest producers but also have a negative impact on consumers who receive poor quality goods at an excessive price and may be exposed to health damages and safety issues. Perfume industry is constantly exposed to the problem of counterfeits with the fast developing parallel market of inspired perfumes being an important issue. It prompts for the identification of methods that classify the quality of this type of products. In this paper the application of proton nuclear magnetic resonance spectroscopy is employed for the authentication of perfumery products for the first time. Molecular composition of several types of authentic brand fragrances for women were compared with their cheaper inspired equivalents and fake products. Our approach offers the prospect of a fast and simple method for discrimination and counterfeit detection of perfumes using 1H NMR spectroscopy.
Effects of Magnetic Fields on the Properties of Water Treatedt by Reversed Osmosis
Mahdi O. Karkush, Mahmoud D. Ahmed, Salim M. Al-Ani
Subject: Engineering, Civil Engineering Keywords: magnetic field; intensity; chemical; electrical properties; osmosis water
The current study focused on reviewing the rapid growing of using magnetic water in different fields of science and measure the influence of several intensities of magnetization on the chemical and electrical properties of tap water treated by reverse osmosis. The work includes circulation of water for 24 h. in magnetic fields of intensity 500, 1000, 1500, and 2000 G. The magnetization of water causes increasing some positive and negative ions in water such as (Mg, K, Na, Cl¯, Alkaline and SiO2) and decreasing some positive and negative ions (Ca and SO3). In the near future, the application of concepts of sustainability development in civil engineering have the to produce structures in harmony with these concepts through using of high-performance materials with less impacts on the environmental and have low cost. The main application of using magnetic water is improvement the geotechnical properties of soil through precipitation of calcite which increases the bond between soil particles and then strength of soil.
Control Domain Wall Motion by Different Depth Trenches in Submicron Permalloy Wires
Cheng-Yi Wu, Shiow-Kang Yen
Subject: Materials Science, Nanotechnology Keywords: domain walls, magnetic force microscope; magnetoresistance; permalloy wire.
Domain walls were studied for permalloy wires with different depth trenches (500 nm wide, 30 nm thick, 7.5 µm long, the depth of the trench was 0, 4, 5, 8, 10, 12 and 15nm). Permalloy (Ni80Fe20) wires were fabricated by electron beam lithography and Ar ion milling. When the depth of trench is smaller than 12 nm, the switching field (Hs) is increasing with the deeper trench. However, the depth of trench is bigger than half depth of thickness, the Hs is decreasing with the deeper trench. We believed that Hs increased as the trench depth increased was because the magnetic diploes force increased between the magnetic poles on two sides of the trench. The domains of the wires were divided by the trenches and the domain walls were pinned on the trenches these were confirmed by magnetic force microscopy images.
First-Principles Prediction of Skyrmionic Phase Behavior in GdFe$_2$ Films Capped by 4$D$ and 5$D$ Transition Metals
Soyoung Jekal, Andreas Danilo, Dao Phoung, Xiao Zheng
Subject: Materials Science, General Materials Science Keywords: skyrmion; Dzyaloshinskii–Moriya interaction; exchange energy; magnetic anisotropy
In atomic GdFe$_2$ films capped by 4$d$ and 5$d$ transition metals, we show that skyrmions with diameters smaller than 12 nm can emerge. The Dzyaloshinskii--Moriya interaction (DMI), exchange energy, and the magnetocrystalline anisotropy (MCA) energy were investigated based on density functional theory. Since DMI and MCA are caused by spin--orbit coupling (SOC), they are increased with 5$d$ capping layers which exhibit strong SOC strength. We discover a skyrmion phase by using atomistic spin dynamic simulations at small magnetic fields of $\sim$1 T. In addition, a ground state that a spin spiral phase is remained even at zero magnetic field for both films with 4$d$ and 5$d$ capping layers.
Is there a Depolarization Horizon?
A. S. Hill
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: Techniques: radio polarization; ISM: turbulence; ISM: magnetic fields
Modern radio spectrometers make measurement of polarized intensity as a function of Faraday depth possible. I investigate the effect of depolarization along a model line of sight. I model sightlines with two components informed by observations: a diffuse interstellar medium with a lognormal electron density distribution and a narrow, denser component simulating a spiral arm or H~{\sc ii} region, all with synchrotron-emitting gas mixed in. I then calculate the polarized intensity from 300-1800 MHz and calculate the resulting Faraday depth spectrum. The idealized synthetic observations show far more Faraday complexity than is observed in Global Magneto-Ionic Medium Survey observations. In a model with a very nearby H~{\sc ii} region observed at low frequencies, most of the effects of a ``depolarization wall'' are evident: the H~{\sc ii} region depolarizes background emission and less (but not zero) information from beyond the H~{\sc ii} region reaches the observer. In other cases, the effects are not so clear, as significant amounts of information reach the observer even through significant depolarization, and it is not clear that low-frequency observations sample largely different volumes of the interstellar medium than high-frequency observations. The observed Faraday depth can be randomized such that it does not always have any correlation with the true Faraday depth.
Application of New Sodium Vinyl Sulfonate-co-2-Acrylamido-2-methylpropane Sulfonic Acid Sodium Salt—Magnetite Cryogel Nanocomposites for Fast Methylene Blue Removal from Industrial Waste Water
Ayman M. Atta, Sami A. Al-Hussain, Hamad A. Al-Lohedan, Abdelrahman O. Ezzat, Ahmed M. Tawfeek
Subject: Chemistry, Applied Chemistry Keywords: methylene blue; water treatment; magnetic nanomaterials; cryogel; nanocomposites
Inorganic nanoparticles based on magnetite improve the mechanical, thermal, and magnetic properties of microporous cryogel polymer composites. Here we report the synthesis of microporous cryogel based on the crosslinked sodium vinyl sulfonate (Na-VS) and 2-acrylamido-2-methylpropane sulfonic acid sodium salt (Na-AMPS). The magnetite nanoparticles were inserted into Na-VS/Na-AMPS cryogel either during its crosslinking polymerization or by in-situ technique after its crosslinking. The morphology, particle sizes, thermal stability and magnetite contents of Na-VS/Na-AMPS cryogel and its magnetite composites were investigated. The prepared Na-VS/Na-AMPS cryogel and its magnetite composites were used as adsorbents for methylene blue (MB) cationic dye using optimum conditions. The magnetite Na-VS/Na-AMPS cryogel composite prepared by in-situ technique achieved the best adsorption MB removal capacity for 7 cycles among the other adsorbents via chemical adsorption mechanism at room temperature.
1H NMR Based Serum Metabolic Profiling Reveals Differentiating Biomarkers in Patients with Diabetes and Diabetes Comorbidity
Atul Rawat, Gunjan Misra, Madhukar Saxena, Sukanya Tripathi, Durgesh Dubey, Sulekha Saxena, Avinash Aggarwal, Varsha Gupta, M Y Khan, Anand Prakash
Subject: Life Sciences, Biochemistry Keywords: Nuclear Magnetic Resonance Spectroscopy, Metabolomics, Biomarker, Random Forest.
Background: Diabetes is among the most prevalent diseases worldwide, of all the affected individuals a significant proportion of the population remains undiagnosed because of a lack of specific symptoms early in this disorder and inadequate diagnostics. Diabetes and its associated sequela, i.e., comorbidity are associated with microvascular and macrovascular complications. As diabetes is characterized by an altered metabolism of key metabolites and regulatory pathways. Metabolic phenotyping can provide us with a better understanding of the unique set of regulatory perturbations that predispose to diabetes and its associated comorbidities. Methodology: The present study utilizes the analytical platform NMR spectroscopy coupled with Random Forest statistical analysis to identify the discriminatory metabolites of diabetes (DB) and diabetes-related comorbidity (DC) along with the healthy control (HC) subjects. A combined and pairwise analysis was performed, between the serum samples of HC (n=50), and DB (n=38), and DC (n=35) individuals to identify the discriminatory metabolites responsible for class separation. The perturbed metabolites were further rigorously validated using t-test, AUROC analysis to examine the statistical significance of the identified metabolites. Results: The DB and DC patients were well discriminated from HC. However, 15 metabolites were found to be significantly perturbed in DC patients compared to DB, the identified panel of metabolites are TCA cycle (succinate, citrate), methylamine metabolism (trimethylamine, methylamine, betaine), -intermediates; energy metabolites (glucose, lactate, pyruvate); and amino acids (valine, arginine, glutamate, methionine, proline and threonine). The metabolites were further used to identify the perturbed metabolic pathway and correlation of metabolites in DC patients. Conclusion: The 1H NMR metabolomics may prove a promising technique to differentiate and predict diabetes and its comorbidities on their onset or progression by determining the altered levels of the metabolites in serum.
Bimetallic Nanoparticles: Enhanced Magnetic and Optical Properties for Emerging Biological Applications
Pannaree Srinoi, Yi-Ting Chen, Varadee Vittur, Maria D. Marquez, T. Randall Lee
Subject: Materials Science, Nanotechnology Keywords: bimetallic nanoparticles; optical properties; magnetic properties; biological applications
Metal nanoparticles are extensively studied due to their unique chemical and physical properties, which differ from the properties of their respective bulk materials. Likewise, the properties of heterogeneous bimetallic structures are far more attractive than those of single-component nanoparticles. The incorporation of a second metal into the nanoparticle structure alters the surface plasmon resonance and magnetic properties of the bimetallic composite. This review focuses on the enhanced optical and magnetic properties offered by bimetallic nanoparticles and their corresponding impact on biological applications. We summarize the predominant structures of bimetallic nanoparticles, outline their synthesis methods, and highlight their use in biological applications, both diagnostic and therapeutic, which are dictated by their various optical and magnetic properties.
Rhodamine Derivative Functionalized Magnetic Nano-Platform for Cu2+ Sensing and Removal
Jiaxin Wang, Shuhan Wang, Wanqing Tian, Dong Yao, Lining Sun, Liyi Shi, Jinliang Liu
Subject: Chemistry, Analytical Chemistry Keywords: copper detection; magnetic nanoparticle; rhodamine B derivative; removal
Pollution caused by copper is one of the key factors of environment contamination. As one of heavy metals, copper is hard to decompose in nature, the biological enrichment of which may lead to severe damage to health. Cu2+ detection, thus, possesses a bright application prospect both in environment protection and in human health. In this paper, a dual-functional fluorescence-magnetic composite nano-platform has been designed to sensitively detect, meanwhile capture and remove Cu2+ in the solution of water and ethanol (1:1, v/v). The core-shell structure nanoparticle synthesized by using Fe3O4 as core and SiO2 as shell, is covalently bonded with rhodamine derivatives on the silica layer to construct the nano-platform. The emission is increased upon the addition of Cu2+, showing fluorescence turn on effect for the detection, and the limit of detection which was as low as 1.68 nM. Meanwhile, Cu2+ ions are captured by the coordination with rhodamine derivatives, and can be removable with the help of magnetic field.
Chitosan-Collagen Coated Magnetic Nanoparticles for Lipase Immobilization – New Type of "Enzyme Friendly" Polymer Shell Crosslinking with Squaric Acid
Marta Ziegler-Borowska, Dorota Chelminiak-Dudkiewicz, Tomasz Siódmiak, Adam Sikora, Katarzyna Wegrzynowska-Drzymalska, Joanna Skopinska-Wisniewska, Halina Kaczmarek, Michał P. Marszałł
Subject: Materials Science, Nanotechnology Keywords: immobilization, lipase, magnetic nanoparticles, chitosan, collagen, squaric acic
The synthesis of new collagen, chitosan and chitosan-collagen coated magnetic nanoparticles have been done. Two types of cross-linkers for polymer shell stabilization were used: glutaraldehyde (Gla) as a standard cross-linker and new one – squaric acid (SqA). Structure and morphology of prepared nanoparticles were characterized by ATR-FT IR, XRD and TEM analysis. The immobilization of lipase from Candida rugosa was performed on the nanoparticles surface. The amount of immobilized enzyme was quantified by the Bradford method. All of lipase-biopolymers coated nanoparticles were characterized with good activity recovery. A little hyperactivation of lipase immobilized on nanoparticles with SqA was observed. All of prepared lipase-immobilized nanoparticles were characterized with very good reusability.
Sensing Magnetic Fields With Magnetosensitive Ion Channels
Igor Goychuk
Subject: Physical Sciences, Other Keywords: magnetic nanoparticles; ion channels; viscoelastic effects and anomalous diffusion; non-exponential statistics; influence of weak magnetic fields on living systems
Magnetic nanoparticles are met across many biological species ranging from magnetosensitive bacteria, fishes, bees, bats, rats, birds, to humans. They can be both of biogenetic origin and due to environmental contamination, being either in paramagnetic or ferromagnetic state. The energy of such naturally occurring single-domain magnetic nanoparticles can reach up to 10-20 room kBT in the magnetic field of the Earth, which naturally led to supposition that they can serve as sensory elements in various animals. This work explores within a stochastic modeling framework a fascinating hypothesis of magnetosensitive ion channels with magnetic nanoparticles serving as sensory elements, especially, how realistic it is given a highly dissipative viscoelastic interior of living cells and typical sizes of nanoparticles possibly involved.
Allocation of Potential Emergency Sections on Pipelines
Emiliia Iakovleva, Margarita Belova, Amilcar Soares
Subject: Earth Sciences, Geophysics Keywords: Earth's natural pulse electromagnetic field; stress-strain state of rock mass; magnetic field strength; magnetic induction; pipeline; measurement; accident; civil communication
The paper presents an analysis of the method of recording the magnetic component of the Earth's natural pulse electromagnetic field in an urban environment. This method of recording has already proved itself to be a method that allocates the stressed sections of rock mass at mining and, therefore, authors suppose its effectiveness for allocating active tectonic disturbances and forecasting accidents at underground utilities, what will help reduce the potential environmental hazard of these objects.
QED and Higgs-like Domain wall in Einstein-Cartan gravity
Luiz Andrade
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: preheating; torsion; Einstein-Cartan; magnetic helicity; Proca Cartan ED
Spacetime torsion is known to be highly suppressed at the end of inflation, called preheating. Of course this fact does not avoid that metric could affect the cosmic dynamos at preheating phase as was showed by Bassett et al, in the general relativity (GR) case. In this paper, is to show that a torsionful magnetogenesis in QED effective lagrangean, drives either a torsion damping or an amplification mechanism or dynamo effect, depending upon torsion chirality. The present extension of Basset et al theory yields a new magnetic field expression $B\sim{a^{(1\pm{\beta})}}$, obtained from dynamo equation in QED. Here a cosmic factor ${\beta}=g_{T}{\eta}k$ is present. In a second example we find Higgs inlationary fields in Einstein-Cartan gravity thick domain walls (DWs). Recently a moodified Einstein-Cartan gravity was given by M Shaposhnikov et al [PRL (2020)] to obtain higgs like inflatons as a portal to dark energy.
Using the Vertical Distribution of Magnetic Susceptibility in the Assessment of Soil Condition in the Krakow Area, Southern Poland
Anna Wojas
Subject: Earth Sciences, Geophysics Keywords: magnetic susceptibility; soil magnetometry; vertical profiles; soil contamination; Krakow
The paper concerns the distribution of apparent magnetic susceptibility in soil profiles located in the areas of topsoil magnetic susceptibility anomalies in Krakow. The type of land use, possible sources of magnetic carriers, and the type of soil were taken into account. Additionally, at each soil profile, a comparison between soil magnetic susceptibility and the results of geochemical analyzes of soil samples was made. The study shows very characteristic changes in magnetic susceptibility with depth, reflecting the interdependencies between natural and anthropogenic factors. A visible magnetic susceptibility maximum at the depth of 10-30 cm is observed at each soil profile. The maximum is associated mainly with the deposition of atmospheric dust and its vertical range depends on the level of anthropopression and natural conditions of soils. At the depth above 40 cm in the eastern part of Krakow, a correlation between the magnetic susceptibility and the soil type (chernozems de-veloped on loess) was found. All indicates that the thicknesses of contaminated upper horizons are not accidental and they depend on human interactions with the environment and the type of soil. An attempt at template establishment with the sources of magnetic particle carriers for different places in the city was made. As the result, in high urbanized sites, the extreme values of magnet-ic susceptibility rapidly change in short vertical distances can identify the richness of anthropo-genic layers with various types of anthropogenic ferrous material and/or additionally Fe-carrying objects buried in soils. In industrialized sites, anthropogenic input plays the most important role in the creation of soil magnetic characteristics. What is more, industrial pollution hides the natural magnetic properties of chernozems. In opposite, the studies at the sites under low anthropopression (mainly located in forests) allow for better insight into magnetic proper-ties arising during pedogenic processes, indirectly giving information about soil conditions. In the forest areas, the lowest values of soil magnetic susceptibility were measured. Additionally, the influence of pedogenic and lithogenic factors on forest soils is manifested in the results. Among the sites concerned, particular attention should be paid to the vicinity of the steel plant because of the agricultural land in the surroundings.
Synthesis, Characterization of Magnetic Composites and Testing of Their Activity in Liquid-phase Oxidation of Phenol with Oxygen
Binara T. Dossumova, Tatyana V. Shakiyeva, Dinara Muktaly, Larissa R. Sassykova, Bedelzhan B. Baizhomartov, Sendilvelan Subramanian
Subject: Chemistry, Chemical Engineering Keywords: catalysts; iron oxides; cobalt; oxygen; oxidation; phenol; magnetic composites
The development and improvement of methods for the synthesis of environmentally friendly catalysts based on base metals is currently an urgent and promising task of modern catalysis. Catalysts based on nanoscale magnetite and maghemite have fast adsorption-desorption kinetics and high chemical activity. The purpose of this work was to obtain magnetic composites, determine their physicochemical characteristics and verify their activity in the process of liquid-phase oxidation of phenol with oxygen. Magnetic nanocomposites were obtained by chemical co-deposition of salts of ferrous and trivalent iron. The synthesized magnetic composites were studied by X-ray diffractometry, energy dispersive X-ray fluorescence and Mössbauer spectroscopy, IR-Fourier spectroscopy, elemental analysis. To increase the catalytic activity in oxidative processes, the magnetite surfaces were modified using cobalt nitrate salt. Further, CoFe2O4 was stabilized by adding polyethylenimine (PEI) as a surfactant. Preliminary studies of the oxidation of phenol with oxygen, as the most typical environmental pollutant were carried out on the obtained Fe3O4, CuFe2O4, CoFe2O4/PEI catalysts. The spectrum of the reaction product shows the presence of CH in the aromatic ring and double C=C bonds, stretching vibrations of the C=O groups of carbonyl compounds; the band at 3059 cm–1 corresponds to the presence of double C=C bonds, the band at 3424 cm–1 hydroquinone compounds. The band at 1678 cm–1 and the intense band at 1646 cm–1 refer to vibrations of the С=О bonds of the carbonyl group of benzoquinone. Peaks at 1366 cm–1 and 1310 cm–1 can be related to the vibrations of C–H and C–C bonds of the quinone ring. Thus it was demonstrated that produced magnetic composites based on iron oxide are quite effective in the oxidation of phenol with oxygen.
A Fuzzy Consensus Clustering Algorithm for MRI Brain Tissue Segmentation
Aruna Kumar S. V., Ehsan Yaghoubi, Hugo Proença
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: Brain Tissue Segmentation; Consensus Clustering; Segmentation; Magnetic Resonance Image
Brain tissue segmentation is an important component of clinical diagnosis of brain diseases by means of multi-modal magnetic resonance imaging (MR). Brain tissue segmentation is developed by many unsupervised methods in literature. The most commonly used unsupervised methods are: K-Means, Expectation Maximization and Fuzzy Clustering. Fuzzy clustering methods offer considerable benefits compared with the aforementioned methods as they are capable of handling brain images which are complex, largely uncertain and imprecise in nature. However, this approach suffers from the intrinsic noise and intensity inhomogeneity (IIH) in the data resulted from the acquisition process. To resolve these issues, we propose a fuzzy consensus clustering algorithm that defines a membership function resulted from a voting schema to cluster the pixels. In particular, we first pre-process the MRI data and employ several segmentation techniques based on traditional fuzzy sets and intuitionistic sets. Then, we adopted a voting schema to fuse the results of the applied clustering methods. Finally, to evaluate the proposed method, we used the well-known performance measures (boundary measure, overlap measure and volume measure) on two publicly available datasets (OASIS and IBSR18). The experimental results show the superior performance of the proposed method in comparison with the recent state of the arts.
On the Localization of Persistent Currents due to Trapped Magnetic Flux at the Stacking Faults of Graphite at Room Temperature
Regina Ariskina, Markus Stiller, Christian Precker, Winfried Böhlmann, Pablo D. Esquinazi
Subject: Physical Sciences, Condensed Matter Physics Keywords: defect-induced superconductivity; graphite; stacking faults; magnetic force microscopy
Granular superconductivity at high temperatures in graphite can emerge at certain two-dimensional (2D) stacking faults (SFs) between regions with twisted (around the c-axis) or untwisted crystalline regions with Bernal (ABA...) and/or rhombohedral (ABCABCA...) stacking order. One way to observe experimentally such 2D superconductivity is to measure the frozen magnetic flux produced by a permanent current loop that remains after removing an external magnetic field applied normal to the SFs. Magnetic force microscopy was used to localize and characterize such a permanent current path found in one natural graphite sample out of ∼50 measured graphite samples of different origins. The position of the current path drifts with time and roughly follows a logarithmic time dependence similar to the one for flux creep in type II superconductors. We demonstrate that a ≃10nm deep scratch on the sample surface at the position of the current path causes a change in its location. A further scratch was enough to irreversibly destroy the remanent state of the sample at room temperature. Our studies clarify some of the reasons for the difficulties of finding a trapped flux in remanent state at room temperature in graphite samples with SFs.
Equivalent Electronic Circuit of a System of Oscillators Connected With Periodically Variable Stiffness
Soumyajit Seth, Grzegorz Kudra, Krzysztof Witkowski, Jan Awrejcewicz
Subject: Physical Sciences, Applied Physics Keywords: Parametric excitation; Dry-Friction; Magnetic Spring Force; Electronic circuit
In this paper, we have shown the electronic circuit equivalence of a mechanical system consists of two oscillators coupled with each other. The mechanical design has the effects of the magnetic, resistance forces and the spring constant of the system is periodically varying. We have shown that the system's state variables, such as the displacements and the velocities, under the effects of different forces, lead to some nonlinear behaviors, like a transition from the fixed point attractor to the chaotic attractor through the periodic and quasi-periodic attractors. We have constructed the equivalent electronic circuit of this mechanical system and have verified the numerically obtained behaviors using the electronic circuit.
Nanotechnology as a Versatile Tool for 19F-MRI Agent's Formulation: A Glimpse into the Use of Perfluorinated and Fluorinated Compounds in Nanoparticles
Joice Maria Joseph, Maria Rosa Gigliobianco, Bita Mahdavi Firouzabadi, Roberta Censi, Piera Di Martino
Subject: Chemistry, Physical Chemistry Keywords: Magnetic resonance imaging; perfluorocarbons; imaging agent; nanosystems; nanoparticles; fluorine
Simultaneously being a non-radiative and non-invasive technique makes magnetic resonance imaging (MRI) one of the highly sought imaging techniques for the early diagnosis and treatment of diseases. Despite more than four decades of research on finding a suitable imaging agent from fluorine for clinical applications, it still lingers as a challenge to get the regulatory approval compared to its hydrogen counterpart. The pertinent hurdle is the simultaneous intrinsic hydrophobicity and lipophobicity of fluorine and its derivatives that make them insoluble in any liquids, strongly limiting their application in areas such as targeted delivery. A blossoming technique to circumvent the unfavorable physicochemical characteristics of perfluorocarbon compounds (PFCs) and guarantee a high local concentration of fluorine in the desired body part is to encapsulate them in nanosystems. In this review, we will be emphasizing different types of nanocarrier systems studied to encapsulate various PFCs and fluorinated compounds, headway to be applied as a contrast agent (CA) in fluorine-19 MRI (19F MRI). We would also scrutinize the different types of PFCs and their specific applications and limitations concerning the nanoparticle (NP) system used to encapsulate them studied over the last decade. A critical evaluation for future opportunities would be speculated.
Magnetic Resonance Imaging in Animal Models of Alzheimer's Disease Amyloidosis
Ruiqing Ni
Subject: Life Sciences, Other Keywords: Alzheimer's disease; magnetic resonance imaging; animal model; amyloid-beta
Amyloid-beta plays an important role in the pathogenesis of Alzheimer's disease. Aberrant amyloid-beta and tau accumulation induce neuroinflammation, cerebrovascular alterations, synaptic deficits, functional deficits, and neurodegeneration, leading to cognitive impairment. Animal models recapitulating the amyloid-beta pathology such as transgenic, knock-in mouse and rat models have facilitated the understanding of disease mechanisms and development of therapeutics targeting at amyloid-beta. There is a rapid advance in high-field MR in small animals. Versatile high-field magnetic resonance imaging (MRI) sequences such as diffusion tensor imaging, arterial spin labelling, resting-state functional MRI, anatomical MRI, MR spectroscopy as well as contrast agents have been developed for the applications in animal models. These tools have enabled high-resolution in vivo structural, functional, and molecular readouts with a whole brain field-of-view. MRI have been utilized to visualize non-invasively the amyloid-beta deposits, synaptic deficits, regional brain atrophy, impairment in white matter integrity, functional connectivity, cerebrovascular and glymphatic system in animal models of amyloidosis. Many of the readouts are translational in clinical MRI in the brain of patients with Alzheimer's disease. In this review, we summarize the recent advance of using MRI for visualizing the pathophysiology in amyloidosis animal model. We discuss the outstanding challenges in brain imaging using MRI in small animal and propose future outlook in visualizing amyloid-beta-related alterations in brain of animal models.
Gravitational-Magnetic-Electric Interaction in Controlling Relative Permittivity and Permeability
Subject: Physical Sciences, General & Theoretical Physics Keywords: Gravitational-electric-magnetic interaction; Controlling permittivity and permeability; Superconductivity
Appling the controlling relative permittivity and permeability in the equations for the gravitational-magnetic-electric field interaction, a very large variation of the gravitational acceleration of the Earth by electric/magnetic field could be arrived at. This conclusion may be supported by some of the experiments for the gravitational effect of superconductivity.
Non-invasive Analysis of Human Liver Metabolism by Magnetic Resonance Spectroscopy
John G. Jones
Subject: Medicine & Pharmacology, General Medical Research Keywords: in vivo magnetic resonance; liver metabolism; hyperpolarization; stable isotopes
The liver is a key node of whole-body nutrient and fuel metabolism and is also the principal site for detoxification of xenobiotic compounds. As such, hepatic metabolite concentrations and/or turnover rates inform the status of both hepatic and systemic metabolic diseases as well as the disposition of medications. As a tool to better understand liver metabolism in these settings, in vivo magnetic resonance spectroscopy (MRS) offers a non-invasive means of monitoring hepatic metabolic activity in real time both by direct observation of concentrations and dynamics of specific metabolites as well as by observation of their enrichment by stable isotope tracers. This review summarizes the applications and advances in human liver metabolic studies by in vivo MRS over the past 35 years and discusses future directions and opportunities that will be opened by the development of ultra-high field MR systems and by hyperpolarized stable isotope tracers.
GMDH Neural Networks - Based Modeling of Variable Power Inductor
Peyman Koohi, Parham Mohammadi, Rahim Samanbakhah, Federico M.Ibanez
Subject: Engineering, Automotive Engineering Keywords: Variable inductor, GMDH – Neural Networks, inductance, magnetic component calculation
In this paper, the Group Method of Data Handling (GMDH) type of neural networks is used for the inductance calculation of variable inductors. The relation between the inductance of the inductor in the linear and nonlinear regions is investigated, and parameters such as the voltage across the inductor, bias current, and ac current are taken into account. The experimental setup is used for generating the data needed for training the neural network. Over 800 experiments were conducted and were used for training and validation of the neural network results. The results are compared with the reluctance equivalent circuit method, and they show a much better accuracy. The proposed method can be used for the calculation of various magnetic components, and it is not limited to variable inductors.
Consistency of Pituitary Adenoma: Prediction by Pharmacokinetic Dynamic Contrast-enhanced MRI and Comparison with Histologic Collagen Content
Kiyohisa Kamimura, Masanori Nakajo, Manisha Bohara, Daigo Nagano, Yoshihiko Fukukura, Shingo Fujio, Tomoko Takajo, Kazuhiro Tabata, Takashi Iwanaga, Hiroshi Imai, Marcel Dominik Nickel, Takashi Yoshiura
Subject: Life Sciences, Biochemistry Keywords: pituitary adenoma; consistency; magnetic resonance imaging; pharmacokinetic analysis; collagen.
Prediction of tumor consistency is valuable for planning transsphenoidal surgery for pituitary adenoma. A prospective study was conducted involving 49 participants with pituitary adenoma to determine whether quantitative pharmacokinetic analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is useful for predicting consistency of adenoma. Pharmacokinetic parameters in the adenomas including volume of extravascular extracellular space (EES) per unit volume of tissue (ve), blood plasma volume per unit volume of tissue (vp), volume transfer constant between blood plasma and EES (Ktrans), and rate constant between EES and blood plasma (kep) were obtained. The pharmacokinetic parameters and the histologic percentage of collagen content (PCC) were compared between soft and hard adenomas using Mann–Whitney U test. Pearson's correla-tion coefficient was used to correlate pharmacokinetic parameters with PCC. Hard adenomas showed significantly higher PCC (44.08 ± 15.14% vs. 6.62 ± 3.47%, p < 0.01), ve (0.332 ± 0.124% vs. 0.221 ± 0.104%, p = 0.02), and Ktrans (0.775 ± 0.401/min vs. 0.601 ± 0.612/min, p = 0.02) than soft adenomas. Moreover, a significant positive correlation was found between ve and PCC (r = 0.601, p < 0.01). The ve derived using DCE-MRI may have predictive value for consistency of pituitary adenoma.
Validation of a Fast and Accurate Magnetic Tracker Operating in the Environmental Field
Valerio Biancalana, Roberto Cecchi, Piero Chessa, Marco Mandalà, Giuseppe Bevilacqua, Yordanka Dancheva, Antonio Vigilante
Subject: Physical Sciences, Applied Physics Keywords: Tracking; Magnetic tracking; Eye tracking; Sensor Array; Eye Motion
We characterize the performance of a system based on a magnetoresistor array. This instrument is developed to map the magnetic field, and to track a dipolar magnetic source in the presence of a static homogeneous field. The position and orientation of the magnetic source with respect to the sensor frame is retrieved together with the orientation of the frame with respect to the environmental field. A nonlinear best-fit procedure is used, and its precision, time performance, and reliability are analyzed. This analysis is performed in view of the practical application for which the system is designed that is an eye-tracking diagnostics and rehabilitative tool for medical purposes, which require high speed ($\ge 100$~Sa/s) and sub-millimetric spatial resolution. A throughout investigation on the results makes it possible to list several observations, suggestions, and hints, which will be useful in the design of similar setups.
Study on Process Derivation and Characteristic Analysis for BLDC Design using Dual Rotor Method with High Torque Density
Byeong-chul Lee, Cheon-ho Song, Do-hyun Kim, Ki-chan Kim
Subject: Engineering, Automotive Engineering Keywords: BLDC; Dual Rotor; Magnetic Equivalent circuit; Operation mode; TRV
In this paper, the design process of BLDC adopting the dual rotor method that can reduce the overall size of the motor while generating the same torque as the conventional Permanent Magnet BLDC is analyzed. A simple size is selected by obtaining the torque per rotor volume (TRV), and a method of matching the counter electromotive force by selecting the pole arc of the magnet through a magnetic equivalent circuit is analyzed. Since the efficiency is low because the 120-degree commutation method is selected, the middle stator is optimized through detailed design through the experimental design method. Afterwards, it has the advantage of being able to shift without stopping due to the characteristic of a dual rotor. For this, an analysis of the driving characteristics for each mode is performed.
Post-Mortem Cardiac Magnetic Resonance for the Diagnosis of Hypertrophic Cardiomyopathy
Giovanni Donato Aquaro, benedetta guidi, federico biondi, enrica chiti, alessandro santurro, matteo scopetti, Emanuela Turillazzi, marco di paolo
Subject: Medicine & Pharmacology, Allergology Keywords: Post-mortem Cardiac magnetic resonance; hypertrophic cardiomyopathy; sudden death
Post-mortem cardiac magnetic resonance (PMCMR) is an emerging tool supporting forensic medicine for the identification of the causes of cardiac death, as hypertrophic cardiomyopathy (HCM). We proposed a new method of PMCMR to diagnose HCM despite myocardial rigor mortis. Methods: we performed CMR in 49 HCM patients, 30 non-HCM hypertrophy and 32 healthy controls. In cine images, rigor mortis was simulated by the analysis of the cardiac phase corresponding to the 25% of diastole. Left ventricular mass, mean and standard deviation (SD) of WT, maximal WT, minimal WT and their difference, were compared for the identification of HCM. These parameters were validated at PMCMR, evaluating 8 hearts with HCM, 10 with coronary artery disease and 10 with non-cardiac death. Results: The SD of WT with a cut-off of > 2.4 had the highest accuracy to identify HCM (AUC 0.95, 95%CI 0.89-0.98). This was particularly evident in female population of HCM (AUC=0.998), with 100% specificity (95%CI 85-100%) and 96% sensitivity (95%CI 79-99%). Using this parameter, at PMCMR all the 8 patients with HCM were correctly identified with no false positive. Conclusions: PMCMR allows to identify HCM as cause of sudden death using the SD of WT >2.4 as diagnostic parameter.
Investigation of the Maturity Changes of Cherry Tomato Using Magnetic Resonance Imaging
Seunghoon Baek, Jongguk Lim, Jun Gu Lee, Michael J. McCarthy, Seong Min Kim
Subject: Physical Sciences, Applied Physics Keywords: magnetic resonance imaging; cherry tomato; maturity change; internal structure
The maturity of tomato fruit is normally characterized by external color and it is often difficult to know when fruit have achieved commercial maturity or become over-mature. The internal structure of tomato fruit change during development and this study investigates the utility of nondestructive measurement of tomato fruit structure as a function of maturity using magnetic resonance imaging (MRI). The objective of this work is to use analysis of internal tomato fruit structural measurements to characterize maturity. Intact cherry tomato fruit were harvested at six different maturity stages. At each stage of maturity, the internal structure of the fruit was measured using a series of 2D magnetic resonance (MR) images. Qualitative and quantitative image analyses were performed to correlate internal fruit structure with maturity. Internal structural changes observed in the pericarp region of the tomato fruit are highly correlated with fruit maturity. MR image information combined with classical analysis techniques provides a more complete understanding of structure and physicochemical changes in tomato fruit during maturation. This study demonstrates that MRI is a useful analytical tool to characterize internal changes in agricultural produce as the produce matures. This technique can be applied to almost any agricultural produce to monitor internal physical changes due to external impact, maturity stage, variation in climate, storage time and condition or other factor impacting quality.
Multiresponsive Hybrid Microparticles for Stimuli-Responsive Delivery of Bioactive Compounds
Sergei Vlasov, Pavel Postnikov, Mikhail Belousov, Sergei Krivoshchekov, Mekhman Yusubov, Artem Guryev, Antonio Di Martino
Subject: Materials Science, Nanotechnology Keywords: Core-shell microparticles; ultrasound; amphiphilic polymer; magnetic microparticles; doxorubicin
Hybrid microparticles based on an iron core and amphiphilic shell have been prepared to respond simultaneously to external (magnetic and ultrasounds field) and internal (pH) stimuli for delivery of the anticancer drug doxorubicin. The microparticles have been prepared in three main steps; including surface modification of the iron core followed by conjugation with the amphiphilic chitosan and drug loading. The particles demonstrate spherical shape and dimension in the range 1-3 m with tunable surface charge by changing the pH of surrounding environment. The microparticles demonstrate good stability in simulated physiological solutions and able to allocate up to 400 g of drug per mg of bare carrier. The response to ultrasound and the changes in the shell structure when exposed to different pH allows to control the doxorubicin release. In vitro cytotoxicity tests performed on fibloblast NIH/3T3 demonstrate a reduction in the cell viability when doxorubicin was administrated by microparticles compared to the free formulation; in particular when ultrasound were applied. The bare microparticles demonstrate cytocompatibility and hemocompatibility up to 50g/mL and 60 g/mL, respectively.