1.
Melting point
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The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium, the melting point of a substance depends on pressure and is usually specified at standard pressure. When considered as the temperature of the change from liquid to solid. Because of the ability of some substances to supercool, the point is not considered as a characteristic property of a substance. For most substances, melting and freezing points are approximately equal, for example, the melting point and freezing point of mercury is 234.32 kelvins. However, certain substances possess differing solid-liquid transition temperatures, for example, agar melts at 85 °C and solidifies from 31 °C to 40 °C, such direction dependence is known as hysteresis. The melting point of ice at 1 atmosphere of pressure is close to 0 °C. In the presence of nucleating substances the freezing point of water is the same as the melting point, the chemical element with the highest melting point is tungsten, at 3687 K, this property makes tungsten excellent for use as filaments in light bulbs. Many laboratory techniques exist for the determination of melting points, a Kofler bench is a metal strip with a temperature gradient. Any substance can be placed on a section of the strip revealing its thermal behaviour at the temperature at that point, differential scanning calorimetry gives information on melting point together with its enthalpy of fusion. A basic melting point apparatus for the analysis of crystalline solids consists of an oil bath with a transparent window, the several grains of a solid are placed in a thin glass tube and partially immersed in the oil bath. The oil bath is heated and with the aid of the melting of the individual crystals at a certain temperature can be observed. In large/small devices, the sample is placed in a heating block, the measurement can also be made continuously with an operating process. For instance, oil refineries measure the point of diesel fuel online, meaning that the sample is taken from the process. This allows for more frequent measurements as the sample does not have to be manually collected, for refractory materials the extremely high melting point may be determined by heating the material in a black body furnace and measuring the black-body temperature with an optical pyrometer. For the highest melting materials, this may require extrapolation by several hundred degrees, the spectral radiance from an incandescent body is known to be a function of its temperature. An optical pyrometer matches the radiance of a body under study to the radiance of a source that has been previously calibrated as a function of temperature, in this way, the measurement of the absolute magnitude of the intensity of radiation is unnecessary. However, known temperatures must be used to determine the calibration of the pyrometer, for temperatures above the calibration range of the source, an extrapolation technique must be employed
2.
Alkane
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In organic chemistry, an alkane, or paraffin, is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a structure in which all the carbon-carbon bonds are single. Alkanes have the chemical formula CnH2n+2. The alkanes range in complexity from the simplest case of methane, CH4 where n =1, in an alkane, each carbon atom has 4 bonds, and each hydrogen atom is joined to one of the carbon atoms. The longest series of linked carbon atoms in a molecule is known as its skeleton or carbon backbone. The number of atoms may be thought of as the size of the alkane. One group of the alkanes are waxes, solids at standard ambient temperature and pressure. They can be viewed as molecular trees upon which can be hung the more functional groups of biological molecules. The alkanes have two main sources, petroleum and natural gas. Saturated hydrocarbons are hydrocarbons having only single covalent bonds between their carbons, according to the definition by IUPAC, the former two are alkanes, whereas the third group is called cycloalkanes. Saturated hydrocarbons can also combine any of the linear, cyclic and branching structures, the formula is CnH 2n−2k+2. Alkanes are the ones, corresponding to k =0. Alkanes with more than three carbon atoms can be arranged in different ways, forming structural isomers. The simplest isomer of an alkane is the one in which the atoms are arranged in a single chain with no branches. This isomer is called the n-isomer. However the chain of atoms may also be branched at one or more points. The number of possible isomers increases rapidly with the number of carbon atoms, for example, 3-methylhexane and its higher homologues are chiral due to their stereogenic center at carbon atom number 3. In addition to the alkane isomers, the chain of atoms may form one or more loops
3.
Sugar
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Sugar is the generic name for sweet, soluble carbohydrates, many of which are used in food. There are various types of derived from different sources. Simple sugars are called monosaccharides and include glucose, fructose, the table sugar or granulated sugar most customarily used as food is sucrose, a disaccharide of glucose and fructose. Sugar is used in prepared foods and it is added to some foods, in the body, sucrose is hydrolysed into the simple sugars fructose and glucose. Other disaccharides include maltose from malted grain, and lactose from milk, longer chains of sugars are called oligosaccharides or polysaccharides. Some other chemical substances, such as glycerol may also have a sweet taste, low-calorie food substitutes for sugar, described as artificial sweeteners, include aspartame and sucralose, a chlorinated derivative of sucrose. Sugars are found in the tissues of most plants and are present in sufficient concentrations for efficient commercial extraction in sugarcane, the world production of sugar in 2011 was about 168 million tonnes. The average person consumes about 24 kilograms of sugar each year, equivalent to over 260 food calories per person, since the latter part of the twentieth century, it has been questioned whether a diet high in sugars, especially refined sugars, is good for human health. Sugar has been linked to obesity, and suspected of, or fully implicated as a cause in the occurrence of diabetes, cardiovascular disease, dementia, macular degeneration, the etymology reflects the spread of the commodity. The English word sugar ultimately originates from the Sanskrit शर्करा, via Arabic سكر as granular or candied sugar, the contemporary Italian word is zucchero, whereas the Spanish and Portuguese words, azúcar and açúcar, respectively, have kept a trace of the Arabic definite article. The Old French word is zuchre and the contemporary French, sucre, the earliest Greek word attested is σάκχαρις. The English word jaggery, a brown sugar made from date palm sap or sugarcane juice, has a similar etymological origin – Portuguese jagara from the Sanskrit शर्करा. Sugar has been produced in the Indian subcontinent since ancient times and it was not plentiful or cheap in early times and honey was more often used for sweetening in most parts of the world. Originally, people chewed raw sugarcane to extract its sweetness, sugarcane was a native of tropical South Asia and Southeast Asia. Different species seem to have originated from different locations with Saccharum barberi originating in India and S. edule, one of the earliest historical references to sugarcane is in Chinese manuscripts dating back to 8th century BC that state that the use of sugarcane originated in India. Sugar was found in Europe by the 1st century AD, but only as an imported medicine and it is a kind of honey found in cane, white as gum, and it crunches between the teeth. It comes in lumps the size of a hazelnut, sugar is used only for medical purposes. Sugar remained relatively unimportant until the Indians discovered methods of turning sugarcane juice into granulated crystals that were easier to store, crystallized sugar was discovered by the time of the Imperial Guptas, around the 5th century AD
4.
Drug
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A drug is any substance that, when inhaled, injected, smoked, consumed, absorbed via a patch on the skin, or dissolved under the tongue, causes a physiological change in the body. In pharmacology, a drug, also called a medication or medicine, is a chemical substance used to treat, cure, prevent. Traditionally drugs were obtained through extraction from plants, but more recently also by organic synthesis. Pharmaceutical drugs may be used for a duration, or on a regular basis for chronic disorders. Another major classification system is the Biopharmaceutics Classification System and this classifies drugs according to their solubility and permeability or absorption properties. Psychoactive drugs are chemical substances that affect the function of the nervous system, altering perception. They include alcohol, a depressant, and the nicotine and caffeine. These three are the most widely consumed psychoactive drugs worldwide and are also considered recreational drugs since they are used for rather than medicinal purposes. Other recreational drugs include hallucinogens, opiates and amphetamines and some of these are used in spiritual or religious settings. Some drugs can cause addiction and all drugs can have side effects, excessive use of stimulants can promote stimulant psychosis. Many recreational drugs are illicit and international such as the Single Convention on Narcotic Drugs exist for the purpose of their prohibition. The transitive verb to drug arose later and invokes the psychoactive rather than properties of a substance. A medication or medicine is a drug taken to cure or ameliorate any symptoms of an illness or medical condition, the use may also be as preventive medicine that has future benefits but does not treat any existing or pre-existing diseases or symptoms. In the United Kingdom, behind-the-counter medicines are called pharmacy medicines which can only be sold in registered pharmacies and these medications are designated by the letter P on the label. The range of medicines available without a prescription varies from country to country, medications are typically produced by pharmaceutical companies and are often patented to give the developer exclusive rights to produce them. Those that are not patented are called generic drugs since they can be produced by other companies without restrictions or licenses from the patent holder, pharmaceutical drugs are usually categorised into drug classes. A group of drugs will share a chemical structure, or have the same mechanism of action. Another major classification system is the Biopharmaceutics Classification System and this groups drugs according to their solubility and permeability or absorption properties
5.
Confectionery
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Confectionery, also called sweets or candy, is sweet food. The term varies among English-speaking countries, in general, though, confectionery is divided into two broad and somewhat overlapping categories, bakers confections and sugar confections. Bakers confectionery, also called flour confections, includes principally sweet pastries, cakes, in the Middle East and Asia, flour-based confections are more dominant. Sugar confectionery includes sweets, candied nuts, chocolates, chewing gum and bubblegum, sweetmeats, pastillage, in some cases, chocolate confections are treated as a separate category, as are sugar-free versions of sugar confections. The words candy, sweets, and lollies are common words for the most common varieties of sugar confectionery, the confectionery industry also includes specialized training schools and extensive historical records. Traditional confectionery goes back to ancient times, and continued to be eaten through the Middle Ages into the modern era, generally, confections are low in micronutrients and protein but high in calories. They may be fat-free foods, although some confections, especially fried doughs, are high-fat foods, many confections are considered empty calories. Specially formulated chocolate has been manufactured in the past for use as a high-density food energy source. Confections are defined by the presence of sweeteners and these are usually sugars, but it is possible to buy sugar-free sweets, such as sugar-free peppermints. The most common sweetener for cooking is table sugar, which is chemically a disaccharide containing both glucose and fructose. Hydrolysis of sucrose gives a mixture called invert sugar, which is sweeter and is also a commercial ingredient. Finally confections, especially commercial ones, are sweetened by a variety of syrups obtained by hydrolysis of starch and these sweeteners include all types of corn syrup. Bakers confectionery includes sweet baked goods, especially those that are served for the dessert course, bakers confections are sweet foods that feature flour as a main ingredient and are baked. Major categories include cakes, sweet pastries, doughnuts, scones, Sugar confections include sweet, sugar-based foods, which are usually eaten as snack food. This includes sugar candies, chocolates, candied fruits and nuts, chewing gum, in the European Union, the Statistical Classification of Economic Activities in the European Community scheme matches the UN classification, under code number 10.82. Ice cream and sorbet are classified with dairy products under ISIC1050, NACE10.52, different dialects of English use regional terms for sugar confections, In Britain, Ireland, and some Commonwealth countries, sweets or, more colloquially, sweeties. In Australia and New Zealand, lollies, chewy and Chuddy are Australian slang for chewing gum. In North America, candy, although this generally refers to a specific range of confectionery
6.
Toothpaste
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Toothpaste is a paste or gel dentifrice used with a toothbrush as an accessory to clean and maintain the aesthetics and health of teeth. Salt and sodium bicarbonate are among materials that can be substituted for commercial toothpaste, in addition to 20–42% water, toothpastes are derived from a variety of components, the three main ones being abrasives, fluoride, and detergents. Abrasives constitute at least 50% of a typical toothpaste and these insoluble particles help remove plaque from the teeth. The removal of plaque and calculus helps minimize cavities and periodontal disease, representative abrasives include particles of aluminum hydroxide, calcium carbonate, various calcium hydrogen phosphates, various silicas and zeolites, and hydroxyapatite. Abrasives, like the dental polishing agents used in dentists offices, some brands contain powdered white mica, which acts as a mild abrasive, and also adds a cosmetically pleasing glittery shimmer to the paste. The polishing of teeth removes stains from tooth surfaces, but has not been shown to improve dental health over and above the effects of the removal of plaque, the abrasive effect of toothpaste is indicated by its RDA value. Too high RDA values should be considered critical, and some dentists recommend toothpaste of an RDA value no higher than 50 for daily use, Fluoride in various forms is the most popular active ingredient in toothpaste to prevent cavities. Fluoride occurs in small amounts in plants, animals, and some water sources. The additional fluoride in toothpaste has beneficial effects on the formation of dental enamel, sodium fluoride is the most common source of fluoride, but stannous fluoride, olaflur, and sodium monofluorophosphate are also used. Stannous fluoride has been shown to be effective than sodium fluoride in reducing the incidence of dental caries and controlling gingivitis. Much of the toothpaste sold in the United States has 1,000 to 1,100 parts per million fluoride, in European countries, such as the UK or Greece, the fluoride content is often higher, a NaF content of 0. 312% w/w is common. Many, although not all, toothpastes contain sodium lauryl sulfate or related surfactants, SLS is found in many other personal care products, as well, such as shampoo, and is mainly a foaming agent, which enables uniform distribution of toothpaste, improving its cleansing power. Despite the different ingredients included in the toothpaste, recent study indicates that brushing with or without toothpaste has no impact on the level of plaque removal, triclosan, an antibacterial agent, is a common toothpaste ingredient in the United Kingdom. Triclosan or zinc chloride prevent gingivitis and, according to the American Dental Association, helps reduce tartar, a 2006 review of clinical research concluded there was evidence for the effectiveness of 0. 30% triclosan in reducing plaque and gingivitis. Toothpaste comes in a variety of colors, and flavors intended to use of the product. Three most common flavorants are peppermint, spearmint, and wintergreen, Toothpaste flavored with peppermint-anise oil is popular in the Mediterranean region. These flavors are provided by the oils, e. g. peppermint oil. More exotic flavors include Anethole anise, apricot, bubblegum, cinnamon, fennel, lavender, neem, ginger, vanilla, lemon, orange, hydroxyapatite nanocrystals and a variety of calcium phosphates are included in formulations for remineralization, i. e. the reformation of enamel
7.
Insulin
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Insulin is a peptide hormone produced by beta cells of the pancreatic islets. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of, especially, glucose from the blood into fat, liver and skeletal muscle cells. In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats via lipogenesis, or, in the case of the liver, Glucose production by the liver is strongly inhibited by high concentrations of insulin in the blood. Circulating insulin also affects the synthesis of proteins in a variety of tissues. It is therefore an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules inside the cells, low insulin levels in the blood have the opposite effect by promoting widespread catabolism. Pancreatic beta cells are known to be sensitive to concentrations in the blood. When glucose concentrations in the blood are high, the pancreatic β cells secrete insulin into the blood, glucagon, through stimulating the liver to release glucose by glycogenolysis and gluconeogenesis, has the opposite effect of insulin. If pancreatic beta cells are destroyed by an reaction, insulin can no longer be synthesized or be secreted into the blood. This results in type 1 diabetes mellitus, which is characterized by high blood glucose concentrations. In type 2 diabetes mellitus the destruction of cells is less pronounced than in type 1 diabetes. Instead there is an accumulation of amyloid in the pancreatic islets, Type 2 diabetes is characterized by high rates of glucagon secretion into the blood which are unaffected by, and unresponsive to the concentration of glucose in the blood glucose. Insulin is still secreted into the blood in response to the blood glucose, as a result, the insulin levels, even when the blood sugar level is normal, are much higher than they are in healthy persons. There are a variety of treatment regimens, none of which is entirely satisfactory, when the pancreas’s capacity to secrete insulin can no longer keep the blood sugar level within normal bounds, insulin injections are given. The human insulin protein is composed of 51 amino acids, and has a mass of 5808 Da. It is a dimer of an A-chain and a B-chain, which are linked together by disulfide bonds, insulins structure varies slightly between species of animals. Insulin from animal sources differs somewhat in effectiveness from human insulin because of these variations, porcine insulin is especially close to the human version, and was widely used to treat type 1 diabetics before human insulin could be produced in large quantities by recombinant DNA technologies. The crystal structure of insulin in the state was determined by Dorothy Hodgkin. It is on the WHO Model List of Essential Medicines, the most important medications needed in a health system
8.
Chewing gum
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Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/ plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. The cultural tradition of chewing gum seems to have developed through a convergent evolution process, each of the early precursors to chewing gum were derived from natural growths local to the region and were chewed purely out the instinctual desire to masticate. Early chewers did not necessarily desire to derive benefits from their chewable substances. Chewing gum in many forms has existed since the Neolithic period,6, 000-year-old chewing gum made from birch bark tar, with tooth imprints, has been found in Kierikki in Finland. The tar from which the gums were made is believed to have antiseptic properties and it is chemically similar to petroleum tar and is in this way different from most other early gum. The Aztecs, as the ancient Mayans before them, used chicle, forms of chewing gums were also chewed in Ancient Greece. The Ancient Greeks chewed mastic gum, made from the resin of the mastic tree, mastic gum, like birch bark tar, has antiseptic properties and is believed to have been used to maintain oral health. Both chicle and mastic are tree resins, many other cultures have chewed gum-like substances made from plants, grasses, and resins. Although chewing gum can be traced back to civilizations around the world, the American Indians chewed resin made from the sap of spruce trees. The New England settlers picked up this practice, and in 1848, John B. Curtis developed, in this way, the industrializing West, having forgotten about tree gums, rediscovered chewing gum through the First Americans. Around 1850 a gum made from wax, which is a petroleum product, was developed. To sweeten these early gums the chewer would often use of a plate of powdered sugar. William Semple filed a patent on chewing gum, patent number 98,304. The first flavored chewing gum was created in the 1860s by John Colgan, Colgan mixed with powdered sugar the aromatic flavoring tolu, a powder obtained from an extract of the balsam tree, creating small sticks of flavored chewing gum he named Taffy Tolu. Colgan also lead the way in the manufacturing and packaging of chicle-based chewing gum, derived from Manilkara chicle, chicle did not succeed as a replacement for rubber, but as a gum, which was cut into strips and marketed as Adams New York Chewing Gum in 1871. Black Jack, which is flavored with licorice, Chiclets, Chewing gum gained worldwide popularity through American GIs in WWII, who were supplied chewing gum as a ration and traded it with locals. Synthetic gums were first introduced to the U. S. after chicle no longer satisfied the needs of making chewing gum
9.
Jmol
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Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D
10.
Ancient Greek
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Ancient Greek includes the forms of Greek used in ancient Greece and the ancient world from around the 9th century BC to the 6th century AD. It is often divided into the Archaic period, Classical period. It is antedated in the second millennium BC by Mycenaean Greek, the language of the Hellenistic phase is known as Koine. Koine is regarded as a historical stage of its own, although in its earliest form it closely resembled Attic Greek. Prior to the Koine period, Greek of the classic and earlier periods included several regional dialects, Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical phases of the language, Ancient Greek was a pluricentric language, divided into many dialects. The main dialect groups are Attic and Ionic, Aeolic, Arcadocypriot, some dialects are found in standardized literary forms used in literature, while others are attested only in inscriptions. There are also several historical forms, homeric Greek is a literary form of Archaic Greek used in the epic poems, the Iliad and Odyssey, and in later poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic, the origins, early form and development of the Hellenic language family are not well understood because of a lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period and they have the same general outline, but differ in some of the detail. The invasion would not be Dorian unless the invaders had some relationship to the historical Dorians. The invasion is known to have displaced population to the later Attic-Ionic regions, the Greeks of this period believed there were three major divisions of all Greek people—Dorians, Aeolians, and Ionians, each with their own defining and distinctive dialects. Often non-west is called East Greek, Arcadocypriot apparently descended more closely from the Mycenaean Greek of the Bronze Age. Boeotian had come under a strong Northwest Greek influence, and can in some respects be considered a transitional dialect, thessalian likewise had come under Northwest Greek influence, though to a lesser degree. Most of the dialect sub-groups listed above had further subdivisions, generally equivalent to a city-state and its surrounding territory, Doric notably had several intermediate divisions as well, into Island Doric, Southern Peloponnesus Doric, and Northern Peloponnesus Doric. The Lesbian dialect was Aeolic Greek and this dialect slowly replaced most of the older dialects, although Doric dialect has survived in the Tsakonian language, which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek, by about the 6th century AD, the Koine had slowly metamorphosized into Medieval Greek
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