High Quality Content by WIKIPEDIA articles! Piperine is the alkaloid responsible for the pungency of black pepper and long pepper, along with chavicine (an isomer of piperine). It has also been used in some forms of traditional medicine and as an insecticide. Piperine forms monoclinic needles, is slightly soluble in water and more so in alcohol, ether or chloroform: the solution in alcohol has a pepper-like taste. It yields salts only with strong acids. The platinichloride B4•H2PtCl6 forms orange-red needles. ("B" denotes one mole of the alkaloid base in this and the following formulae.) Iodine in potassium iodide added to an alcoholic solution of the base in presence of a little hydrochloric acid gives a characteristic periodide,...
High Quality Content by WIKIPEDIA articles! The pit is the core of an implosion weapon – the fissile material and any neutron reflector or tamper bonded to it. Some weapons tested during the 1950s used pits made with U-235 alone, or in composite with plutonium, but all-plutonium pits are the smallest in diameter and have been the standard since the early 1960s.
High Quality Content by WIKIPEDIA articles! Pitmilly is the site of a former estate located five miles south-east of St Andrews, Scotland. Its historical significance is threefold. It has been inhabited from ancient times; artifacts continue to be recovered from the Neolithic, Bronze and Iron Ages and a well-known barrow (burial mound) Tumulus from the Bronze Age still exists there. It is connected to Clan Hay in that Eva of Pitmilly, the Celtic heiress to these lands, married William II de Haya, a Norman, in the 12th century C.E., with the couple becoming the progenitors of that Scottish clan. Finally, for over seven centuries, it was owned by the important Moneypenny family.
High Quality Content by WIKIPEDIA articles! Peptide signaling plays a significant role in various aspects of plant growth and development and specific receptors for various peptides have been identified as being membrane-localized receptor kinases, the largest family of receptor-like molecules in plants. Signaling peptides include members of the following protein families.
High Quality Content by WIKIPEDIA articles! Plaster is a building material used for coating walls and ceilings. Plaster starts as a dry powder similar to mortar or cement and like those materials it is mixed with water to form a paste which liberates heat and then hardens. Unlike mortar and cement, plaster remains quite soft after setting, and can be easily manipulated with metal tools or even sandpaper. These characteristics make plaster suitable for a finishing, rather than a load-bearing material.
High Quality Content by WIKIPEDIA articles! Platinum coins are a form of currency. Platinum has an international currency symbol under ISO 4217 of XPT. The issues of legitimate platinum coins were initiated by Spain in Spanish-colonized America in the 18th century and continued by the Russian Empire in the 19th century. As a form of currency, these coins proved to be impractical: platinum resembles many less expensive metals, and, unlike the more malleable and ductile silver and gold, it is very difficult to work. Several commemorative coin sets have been issued starting from 1978 and became popular among coin collectors. The major platinum bullion coins include the American Platinum Eagle, the Canadian Platinum Maple Leaf, the...
High Quality Content by WIKIPEDIA articles! In chemistry, a plumbate is a salt having one of the several lead-containing oxoanions. Although the term plumbate can refer either to plumbate(II) or plumbate(IV), it traditionally refers specifically to plumbate(IV), whereas plumbate(II) is referred to as plumbite.
High Quality Content by WIKIPEDIA articles! Since the mid-20th century, plutonium in the environment has primarily been produced by human activity. The majority of plutonium isotopes are short-lived on a geological timescale, though it has been argued that some natural plutonium, like the long-lived 244Pu isotope, can be found in nature. This isotope has been found in lunar soil,meteorites, and in the Oklo natural reactor. However, one paper on marine sediments for plutonium in marine sediments, atomic bomb fallout is responsible for 66% of the 239Pu and 59% 240Pu found in the English Channel, while nuclear reprocessing is responsible for the majority of the 238Pu and 241Pu present in the Earth`s oceans (nuclear weapons testing is only...
High Quality Content by WIKIPEDIA articles! Pobedit (победит) is a sintered carbide alloy of about 90 % tungsten carbide as a hard phase, and about 10 % cobalt (Co) as a binder phase, with a small amount of additional carbon. Invented in the Soviet Union in 1929, it is described as a material from which cutting tools are made. Later a number of similar alloys based on tungsten and cobalt were developed.
High Quality Content by WIKIPEDIA articles! Podgorica Aluminium Plant (Montenegrin: Kombinat Aluminijuma Podgorica - KAP) (MNSE: KAPG) is an aluminium processing plant, located on the southern outskirts of Podgorica, Montenegro.
High Quality Content by WIKIPEDIA articles! Podophyllotoxin (abbreviated as PPT), otherwise known as podofilox, is a non-alkaloid toxin lignan extracted from the roots and rhizomes of Podophyllum species. Under the trade name Condylox, a topical gel, it is used on the skin to treat external genital warts, caused by some types of the human papillomavirus (HPV). PPT and its derivatives display a wide selection in medical applications such as purgative, vesicant, antirheumatic, antiviral, and antitumor agents. These derivatives include etoposide, teniposide, and etopophos. Their anticancer activity has been heavily under study and used in various chemotherapies, including lung cancer, lymphomas, and genital tumors.
High Quality Content by WIKIPEDIA articles! A polaron is a quasiparticle composed of a charge and its accompanying polarization field. A slow moving electron in a dielectric crystal, interacting with lattice ions through long-range forces will permanently be surrounded by a region of lattice polarization and deformation caused by the moving electron. Moving through the crystal, the electron carries the lattice distortion with it, thus one speaks of a cloud of phonons accompanying the electron.
High Quality Content by WIKIPEDIA articles! Polyhalogen ions are a group of polyatomic cations and anions containing halogens only. The ions can be classified into two classes, isopolyhalogen ions which contain one type of halogen only, and heteropolyhalogen ions with more than one type of halogen.
High Quality Content by WIKIPEDIA articles! Polyprenols are natural long-chain isoprenoid alcohols of the general formula H-(C5H8)n-OH where n is the number of isoprene units. Any prenol with more than 4 isoprene units is a polyprenol. Polyprenols play an important function acting as natural bioregulators and are found in small quantities in various plant tissues. Dolichols, which are found in all living creatures, including man, are their 2,3-dihydro derivatives.
High Quality Content by WIKIPEDIA articles! Polysilazanes are polymers in which silicon and nitrogen atoms alternate to form the basic backbone. Since each silicon atom is bound to two separate nitrogen atoms and each nitrogen atom to two silicon atoms, both chains and rings of the formula n occur. R1-R3 can be hydrogen atoms or organic substituents. If all substituents R are H atoms, the polymer is designated as Perhydropolysilazane, Polyperhydridosilazane or Inorganic Polysilazane (n). If hydrocarbon substituents are bound to the silicon atoms, the polymers are designated as Organopolysilazanes. Molecularly, polysilazanes n are isoelectronic with and close relatives to Polysiloxanes n (silicones).
High Quality Content by WIKIPEDIA articles! Ponceau 4R (also known as C.I. 16255 , Cochineal Red A, C.I. Acid Red 18, Brilliant Scarlet 3R, Brilliant Scarlet 4R, New Coccine) , SX purple) is a synthetic colourant that may be used as a food colouring. It is denoted by E Number E124. Its chemical name is 1-(4-sulpho-1-napthylazo)- 2-napthol- 6,8-disulphonic acid, trisodium salt.
High Quality Content by WIKIPEDIA articles! Positronium (Ps) is a system consisting of an electron and its anti-particle, a positron, bound together into an "exotic atom". Being unstable, the two particles annihilate each other to produce two gamma ray photons after an average lifetime of 125 ps or three gamma ray photons after 142 ns in vacuum, depending on the relative spin states of the positron and electron. The orbit of the two particles and the set of energy levels is similar to that of the hydrogen atom (electron and proton). However, because of the reduced mass, the frequencies associated with the spectral lines are less than half of those of the corresponding hydrogen lines.
High Quality Content by WIKIPEDIA articles! Potassium sorbate is the potassium salt of sorbic acid, chemical formula C6H7KO2. Its primary use is as a food preservative (E number 202). Potassium sorbate is effective in a variety of applications including food, wine, and personal care products.