KI is also used as a fluorescence quenching agent in biomedical research, an application that takes advantage of collisional quenching of fluorescent substances by the iodide ion. However, for several fluorophores addition of KI in μM-mM concentrations results in increase of fluorescence intensity, and iodide acts as fluorescence enhancer.Potassium iodide is a component in the electrolyte of dye sensitised solar cells (DSSC) along with iodine. Potassium iodide finds its most important applications in organic synthesis mainly in the preparation of aryl iodides in the Sandmeyer reaction, starting from aryl amines. Aryl iodides are in turn used to attach aryl groups to other organics by nucleophilic substitution, with iodide ion as the leaving group. Chemistry
Potassium iodide is an ionic compound which is made of the following ions: K+I−. It crystallises in the sodium chloride structure. It is produced industrially by treating KOH with iodine.It is a white salt, which is the most commercially significant iodide compound, with approximately 37,000 tons produced in 1985. It absorbs water less readily than sodium iodide, making it easier to work with. Aged and impure samples are yellow because of the slow oxidation of the salt to potassium carbonate and elemental iodine.
Psychasthenia was a psychological disorder characterized by phobias, obsessions, compulsions, or excessive anxiety. The term is no longer in psychiatric diagnostic use, although it still forms one of the ten clinical subscales of the popular self-report personality inventories MMPI and MMPI-2. Signs and symptoms
The MMPI subscale 7 describes psychasthenia as akin to obsessive-compulsive disorder, and as characterised by excessive doubts, compulsions, obsessions, and unreasonable fears. The psychasthenic has an inability to resist specific actions or thoughts, regardless of their maladaptive nature. In addition to obsessive-compulsive features, the scale taps abnormal fears, self-criticism, difficulties in concentration, and guilt feelings. The scale assesses long-term (trait) anxiety, although it is somewhat responsive to situational stress as well. The psychasthenic has insufficient control over their conscious thinking and memory, sometimes wandering aimlessly and/or forgetting what they were doing. Thoughts can be scattered and take significant effort to organize, often resulting in sentences that do not come out as intended, therefore making little sense to others. The constant mental effort and characteristic insomnia induces fatigue, which worsens the condition. Symptoms can possibly be greatly reduced with concentration exercises and therapy, depending on whether the condition is psychological or biological. History
The term "psychasthenia" is historically associated primarily with the work of Pierre Janet, who divided the neuroses into the psychasthenias and the hysterias, discarding the term "neurasthenia" since it implied a neurological theory where none existed.