High Quality Content by WIKIPEDIA articles! Peramivir is an experimental antiviral drug developed by BioCryst Pharmaceuticals for the treatment of influenza. It has been authorized for the emergency use of treatment of certain hospitalized patients with known or suspected 2009 H1N1 influenza.
High Quality Content by WIKIPEDIA articles! Perchlorates are the salts derived from perchloric acid (HClO4). They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders. They are used extensively within the pyrotechnics industry, and ammonium perchlorate is also a component of solid rocket fuel. Lithium perchlorate, which decomposes exothermically to give oxygen, is used in oxygen "candles" on spacecraft, submarines and in other esoteric situations where a reliable backup or supplementary oxygen supply is needed. Most perchlorate salts are soluble in water.
High Quality Content by WIKIPEDIA articles! Perchloromethyl mercaptan,CCl3S, is mainly used as an intermediate for the synthesis of dyes and fungicides (captan, folpet). It is an oily, pale yellow liquid, which is insoluble in water, with a foul-smelling, unbearable, acrid odor. When it is heated or in a fire, it will emit toxic and corrosive gases. It is also very toxic by inhalation or skin absorption.
High Quality Content by WIKIPEDIA articles! Perfluorooctanesulfonamide (PFOSA) is a synthetic organofluorine compound. It is a fluorocarbon derivative, or perfluorinated compound, with eight carbons and a terminal sulfonamide functional group. PFOSA was an ingredient in 3M`s former Scotchgard formulation and the compound was used to repel grease and water in food packaging along with other consumer applications. It breaks down to form perfluorooctane sulfonate (PFOS). The perfluorooctanesulfonyl fluoride-based chemistry that was used to make sulfonamides like PFOSA was phased out by 3M in the United States (US) during 2000–2002 but it has grown in China by other producers.
High Quality Content by WIKIPEDIA articles! A period 4 element is one of the chemical elements in the fourth row (or period) of the periodic table of the elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fourth period contains 18 elements, beginning with potassium and ending with krypton. As a rule, period 4 elements fill their 4s shells first, then their 3d and 4p shells, in that order, however there are exceptions, such as chromium.
High Quality Content by WIKIPEDIA articles! A period 8 element is any one of 46 hypothetical chemical elements (ununennium through unhexquadium) belonging to an eighth period of the periodic table of the elements. Sometimes, elements 169 to 172 are also considered to be in period 8 as their outermost electrons fill the 8p3/2 subshells, despite behaving chemically more like the period 9 elements. They may be referred to using IUPAC systematic element names. None of these elements have been synthesized, and it is possible that none have isotopes with stable enough nuclei to receive significant attention in the near future. It is also probable that, due to drip instabilities, only the lower period 8 elements are physically possible and the...
High Quality Content by WIKIPEDIA articles! A period 2 element is one of the chemical elements in the second row (or period) of the periodic table. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases; a new row is started when chemical behavior begins to repeat, creating columns of elements with similar properties.
High Quality Content by WIKIPEDIA articles! Periodic systems of molecules are charts of molecules similar to the periodic table of the elements. Construction of such charts was initiated in the early 20th century and is still ongoing.
High Quality Content by WIKIPEDIA articles! A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fifth period contains 18 elements, beginning with rubidium and ending with xenon. As a rule, period 5 elements fill their 5s shells first, then their 4d, and 5p shells, in that order, however there are exceptions, such as rhodium.
High Quality Content by WIKIPEDIA articles! The alternative periodic table is a standard periodic table rotated counter-clockwise and then mirrored across the vertical axis, so that the lower groups are to the left and the number increases to the right. Due to the rotation and the incorporation of the lanthanides and actinides into the main table, the Alternative Table is significantly longer vertically than the Standard Table. Its restricted width allows it to be read on-line without needing to scroll horizontally. It also allows more information in each cell such as the full name of an element.
High Quality Content by WIKIPEDIA articles! In the periodic table of the elements, elements are arranged in a series of rows (or periods) so that those with similar properties appear in a column. Elements of the same period have the same number of electron shells; with each group across a period, the elements have one more proton and electron and become less metallic. This arrangement reflects the periodic recurrence of similar properties as the atomic number increases. For example, the alkaline metals lie in one group (group 1) and share similar properties, such as high reactivity and the tendency to lose one electron to arrive at a noble-gas electronic configuration. The periodic table of elements has a total of 118 elements.
High Quality Content by WIKIPEDIA articles! The Permafrost Carbon Cycle is a sub-cycle of the larger global carbon cycle. Permafrost is defined as subsurface material that remains below 0o C (32o F) for at least two consecutive years. Because permafrost soils remain frozen for long periods of time, they store large amounts of carbon and other nutrients within their frozen framework during that time. Permafrost represents a large carbon reservoir that is seldom considered when determining global terrestrial carbon reservoirs. Recent and ongoing scientific research however, is changing this view.
High Quality Content by WIKIPEDIA articles! Permalloy is a nickel-iron magnetic alloy, with about 20% iron and 80% nickel content. It is notable for its very high magnetic permeability, which makes it useful as a magnetic core material in electrical and electronic equipment, and also in magnetic shielding to block magnetic fields. Commercial permalloy alloys typically have relative permeability of around 100,000, compared to several thousand for ordinary steel.
High Quality Content by WIKIPEDIA articles! Permethrin is a common synthetic chemical, widely used as an insecticide, acaricide, and insect repellent. It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to rapidly harm most mammals or birds, but is dangerously toxic to cats and fish. In general, it has a low mammalian toxicity and is poorly absorbed by skin.
High Quality Content by WIKIPEDIA articles! Peroxidases (EC number 1.11.1.x) are a large family of enzymes that typically catalyze a reaction of the form:
High Quality Content by WIKIPEDIA articles! Perphenazine is a typical antipsychotic drug. Chemically, it is classified as a piperazinyl phenothiazine. It has been in clinical use for decades.
High Quality Content by WIKIPEDIA articles! Pewter is a malleable metal alloy, traditionally 85–99% tin, with the remainder consisting of copper, antimony, bismuth and lead. Copper and antimony act as hardeners while lead is common in the lower grades of pewter, which have a bluish tint. It has a low melting point, around 170–230 °C (338–446°F), depending on the exact mixture of metals. The word pewter is probably a variation of the word spelter, a colloquial name for zinc.