Zinc reserves, on the other hand, are geologically identified ore bodies whose suitability for recovery is economically based (location, grade, quality, and quantity) at the time of determination. Since exploration and mine development is an ongoing process, the amount of zinc reserves is not a fixed number and sustainability of zinc ore supplies cannot be judged by simply extrapolating the combined mine life of todays zinc mines. This concept is well supported by data from the United States Geological Survey (USGS), which illustrates that although refined zinc production increased 80% between 1990 and 2010, the reserve lifetime for zinc has remained unchanged. About 346 million tonnes have been extracted throughout history to 2002, and scholars have estimated that about 109–305 million tonnes are in use. Isotopes
Five stable isotopes of zinc occur in nature, with 64Zn being the most abundant isotope (49.17% natural abundance). The other isotopes found in nature are 66Zn (27.73%), 67Zn (4.04%), 68Zn (18.45%), and 70Zn (0.61%).Several dozen radioisotopes have been characterized. 65Zn, which has a half-life of 243.66 days, is the least active radioisotope, followed by 72Zn with a half-life of 46.5 hours. Zinc has 10 nuclear isomers, of which 69mZn has the longest half-life, 13.76 h. The superscript m indicates a metastable isotope. The nucleus of a metastable isotope is in an excited state and will return to the ground state by emitting a photon in the form of a gamma ray. 61Zn has three excited metastable states and 73Zn has two.
Triheptanoin, sold under the brand name Dojolvi, is a medication for the treatment of children and adults with molecularly confirmed long-chain fatty acid oxidation disorders (LC-FAOD).The most common adverse reactions include abdominal pain, diarrhea, vomiting, and nausea.Triheptanoin was approved for medical use in the United States in June 2020.Triheptanoin is a triglyceride that is composed of three seven-carbon (C7:0) fatty acids. These odd-carbon fatty acids are able to provide anaplerotic substrates for the TCA cycle. Triheptanoin is used clinically in humans to treat inherited metabolic diseases, such as pyruvate carboxylase deficiency and carnitine palmitoyltransferase II deficiency. It also appears to increase the efficacy of the ketogenic diet as a treatment for epilepsy. Since triheptanoin is composed of odd-carbon fatty acids, it can produce ketone bodies with five carbon atoms, as opposed to even-carbon fatty acids which are metabolized to ketone bodies with four carbon atoms. The five-carbon ketones produced from triheptanoin are beta-ketopentanoate and beta-hydroxypentanoate. Each of these ketone bodies easily crosses the blood–brain barrier and enters the brain. Medical uses
Dojolvi is indicated as a source of calories and fatty acids for the treatment of children and adults with molecularly confirmed long-chain fatty acid oxidation disorders (LC-FAOD). History
Triheptanoin was designated an orphan drug by the U.S. Food and Drug Administration (FDA) in 2006, 2008, 2014, and 2015.