Cesium

"Caesium or cesium is a chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C (82 °F), which makes it one of only five elemental metals that are liquid at (or near) room temperature.^{[note 2]} Caesium is an alkali metal and has physical and chemical properties similar to those of rubidium and potassium. The metal is extremely reactive and pyrophoric, reacting with water even at −116 °C (−177 °F). It is the least electronegative element having a stable isotope, caesium-133. Caesium is mined mostly from pollucite, while the radioisotopes, especially caesium-137, a fission product, are extracted from waste produced by nuclear reactors."

"Two German chemists, Robert Bunsen and Gustav Kirchhoff, discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium were as a "getter" in vacuum tubes and in photoelectric cells. In 1967, a specific frequency from the emission spectrum of caesium-133 was chosen to be used in the definition of the second by the International System of Units. Since then, caesium has been widely used in atomic clocks."

"Since the 1990s, the largest application of the element has been as caesium formate for drilling fluids. It has a range of applications in the production of electricity, in electronics, and in chemistry. The radioactive isotope caesium-137 has a half-life of about 30 years and is used in medical applications, industrial gauges, and hydrology. Although the element is only mildly toxic, it is a hazardous material as a metal and its radioisotopes present a high health risk if released into the environment."

Phosphine oxide

"Phosphine oxides are phosphorus compounds with the formula OPX₃. When X = alkyl or aryl, these are organophosphine oxides. Triphenylphosphine oxide is an example. An inorganic phosphine oxide is phosphoryl trichloride (Cl₃PO). Such compounds are thermally stable, decomposing only above 450 °C.^[1] Phosphoryl refers to a functional group drawn with a phosphorus-oxygen double bond."

"According to Molecular Orbital Theory, the short P-O bond is attributed to the donation of the lone pair electrons from oxygen p-orbitals to the antibonding phosphorus-carbon bonds; In Valence Bond terms this means having a P=O double bond and a delocalized four-center six-electron P-Cl system occupying two orbitals. This proposal, which is supported by ab initio calculations, has gained consensus in the chemistry community."

"The nature of the phosphorus to oxygen bonding was once hotly debated, as the involvement of a phosphorus d-orbitals in bonding is not supported by computational analyses. In terms of simple Lewis structure, the bond is more accurately represented as a dative bond, as is currently used to depict an amine oxide."

o-Phenylenediamine

"o-Phenylenediamine is a organic compound with the formula C₆H₄(NH₂)₂. This aromatic diamine is an important precursor to many heterocyclic compounds. It is isomeric with m-phenylenediamine and p-phenylenediamine, and is commonly referred to as OPD."

"o-Phenylenediamine condenses with ketones and aldehydes to give rise to a variety of useful products. Reactions with carboxylic acids and their derivatives afford benzimidazoles. The herbicide benomyl is prepared in this manner. Also, quinoxalinedione may be prepared by condensation of o-phenylenediamine with dimethyl oxalate. Condensation with xanthate esters affords mercaptoimidazoles, which are used as antioxidants in rubber products. Treatment with nitrous acid give benzotriazole, a corrosion inhibitor. Condensation of substituted o-phenylenediamine with various diketones is used in the preparation of a variety of pharmaceuticals."

Vanadium

Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The element is found only in chemically combined form in nature, but once isolated artificially, the formation of an oxide layer stabilizes the free metal somewhat against further oxidation. Andrés Manuel del Río discovered compounds of vanadium in 1801 by analyzing a new lead-bearing mineral he called "brown lead," and presumed its qualities were due to the presence of a new element, which he namederythronium (Greek for "red") since, upon heating, most of its salts turned from their initial color to red. Four years later, however, he was convinced by other scientists that erythronium was identical to chromium. Chlorides of vanadium were generated in 1830 by Nils Gabriel Sefström who thereby proved that a new element was involved, which he named "vanadium" after the Germanic goddess of beauty and fertility, Vanadís (Freyja). Both names were attributed to the wide range of colors found in vanadium compounds. Del Rio's lead mineral was later renamed vanadinite for its vanadium content. Although Berzelius claimed to have first isolated vanadium in the 1830s, in 1867 Henry Enfield Roscoe showed that he had only obtained the oxide, and finally in 1869 Roscoe demonstrated a method to obtain the pure element.

Large amounts of vanadium ions are found in a few organisms, possibly as a toxin. The oxide and some other salts of vanadium have moderate toxicity. Particularly in the ocean, vanadium is used by some life forms as an active center of enzymes, such as the vanadium bromoperoxidase of some ocean algae. Vanadium is probably a micronutrient in mammals, including humans, but its precise role in this regard is unknown.

Phytosterol

"Phytosterols, which encompass plant sterols and stanols, are steroid compounds similar to cholesterol which occur in plants and vary only in carbon side chains and/or presence or absence of a double bond. Stanols are saturated sterols, having no double bonds in the sterol ring structure. More than 200 sterols and related compounds have been identified.^[1] Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols."

"Phytosterol-enriched foods and dietary supplements have been marketed for decades. Despite well documented cholesterol-lowering effect, no evidence of any beneficial effect on cardiovascular disease (CVD) or overall mortality exists."

"The richest naturally occurring sources of phytosterols are vegetable oils and products made from them. Nuts, which are rich in phytosterols, are often eaten in smaller amounts, but can still significantly contribute to total phytosterol intake. Cereal products, vegetables, fruit and berries, which are not as rich in phytosterols, may also be significant sources of phytosterols due to their higher intakes.^[3] The intake of naturally occurring phytosterols ranges between ~150–450 mg/day^[4] depending on eating habits."

Disulfide Bond

"In chemistry, a disulfide bond (Br.E. disulphide bond) is a covalent bond, usually derived by the coupling of two thiol groups. The linkage is also called an SS-bond or disulfide bridge. The overall connectivity is therefore R-S-S-R. The terminology is widely used in biochemistry. In formal terms, the connection is a persulfide, in analogy to its congener, peroxide (R-O-O-R), but this terminology is obscure and is no longer used (except in reference to R-S-S-H or H-S-S-H compounds)."

"The disulfide bond is strong, with a typical bond dissociation energy of 60 kcal/mole (251 kJ mol^-1). However, being about 40% weaker than C-C and C-H bonds, the disulfide bond is often the "weak link" in many molecules. Furthermore, reflecting the polarizability of divalent sulfur, the S-S bond is susceptible to scission by polar reagents, both electrophiles and especially nucleophiles:"

RS-SR + Nu^- → RS-Nu + RS^-

"The disulfide bond is about 2.05 Å in length, about 0.5 Å longer than a C-C bond. Rotation about the S-S axis is subject to a low barrier. Disulfides show a distinct preference for dihedral angles approaching 90°. When the angle approaches 0° or 180°, then the disulfide is a significantly better oxidant."

Ferroelectric Polymers

"Ferroelectric Polymers ^[1] [2] are a group of crystalline polar polymers that are also ferroelectric, meaning that they maintain a permanent electric polarization that can be reversed, or switched, in an external electric field."

"Ferroelectric polymers, such as polyvinylidene fluoride (PVDF), are used in acoustic transducers and electromechanical actuators because of their inherent piezoelectric response, and as heat sensors because of their inherent pyroelectric response."

"A ferroelectric polymer must contain permanent electrical polarization that can be reversed repeatedly, by an opposing electric field.^[4] In the polymer, dipoles can be randomly oriented, but application of an electric field will align the dipoles, leading to ferroelectric behavior. In order for this effect to happen, the material must be below its Curie Temperature.^[5] Above the Curie Temperature, the polymer exhibits paraelectric behavior, which does not allow for ferroelectric behavior because the electric fields do not align."

Chlorodifluoromethane

"Chlorodifluoromethane or difluoromonochloromethane is a hydrochlorofluorocarbon (HCFC). This colorless gas is better known as HCFC-22, or R-22. It is commonly used as a propellant and refrigerant. These applications are being phased out in developed countries due to the compound's ozone depletion potential (ODP) and high global warming potential(GWP), although global use of R-22 continues to increase because of high demand in developing countries.^[1] R-22 is a versatile intermediate in industrial organofluorine chemistry, e.g. as a precursor to tetrafluoroethylene."

"Worldwide production of R-22 in 2008 was about 800 Gg per year, up from about 450 Gg per year in 1998, with most production in developing countries.^[1] R-22 use is increasing in developing countries, largely for air conditioning applications. Air conditioning sales are growing 20% annually in India and China."

R-22 is prepared from chloroform:

Cholecystokinin

Cholecystokinin (CCK or CCK-PZ; from Greek chole, "bile"; cysto, "sac"; kinin, "move"; hence, move the bile-sac (gallbladder)) is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein. Cholecystokinin, previously called pancreozymin, is synthesized by I-cells in the mucosal epithelium of the small intestine and secreted in the duodenum, the first segment of the small intestine, and causes the release of digestive enzymes and bile from the pancreas andgallbladder, respectively. It also acts as a hunger suppressant. Recent evidence has suggested that it also plays a major role in inducing drug tolerance to opioids likemorphine and heroin, and is partly implicated in experiences of pain hypersensitivity during opioid withdrawal.

CCK is composed of varying numbers of amino acids depending on post-translational modification of the CCK gene product, preprocholecystokinin. Thus CCK is actually a family of hormones identified by number of amino acids, e.g., CCK58, CCK33, and CCK8. CCK58 assumes a helix-turn-helix configuration.^[3] Its existence was first suggested in 1905 by the British physiologist Joy Simcha Cohen. CCK is very similar in structure to gastrin, another of the gastrointestinal hormones. CCK and gastrin share the same five amino acids at their C-termini.

Norepinephrine

"Norepinephrine (INN) (abbreviated norepi or NE), or noradrenaline (BAN) (abbreviated NA, NAd, or norad), is a catecholamine with multiple roles including as a hormone and a neurotransmitter.^[3] Areas of the body that produce or are affected by norepinephrine are described as noradrenergic."

"The terms noradrenaline (from the Latin) and norepinephrine (derived from Greek) are interchangeable, with noradrenaline being the common name in most parts of the world. However, to avoid confusion and achieve consistency, medical authorities have promoted norepinephrine as the favoured nomenclature, and this is the term used throughout this article."

"One of the most important functions of norepinephrine is its role as the neurotransmitter released from the sympathetic neurons affecting the heart. An increase in norepinephrine from the sympathetic nervous system increases the rate of contractions."