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Adolph Strecker
Adolph Strecker (October 21, 1822 – November 7, 1871) was a German chemist who is remembered primarily for his work with amino acids. Life and work Strecker was born in Darmstadt, the son of Friedrich Ludwig Strecker, an archivist working for the hessian Grand Duke, and Henriette Amalie Johannette Koch. Adolph Strecker attended school in Darmstadt until 1838 when he changed to the higher Gewerbeschule. After receiving his abitur in 1840, Strecker began studying science at the University of Giessen, where Justus Liebig was a professor. In August 1842, Strecker received his PhD and began teaching at a realschule in Darmstadt. He refused one offer to work for Liebig, but in 1846 he accepted another and became Liebig's private assistant at the University of Giessen. Strecker finished his habilitation in 1848 and became a lecturer at the university. Strecker investigated a wide variety of problems in both organic and inorganic chemistry during his time at Giessen. Examples include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darmstadt
Darmstadt () is a city in the state of Hesse in Germany, located in the southern part of the Rhine-Main-Area (Frankfurt Metropolitan Region). Darmstadt has around 160,000 inhabitants, making it the fourth largest city in the state of Hesse after Frankfurt am Main, Wiesbaden, and Kassel. Darmstadt holds the official title "City of Science" (german: link=no, Wissenschaftsstadt) as it is a major centre of scientific institutions, universities, and high-technology companies. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the European Space Operations Centre (ESOC) are located in Darmstadt, as well as GSI Centre for Heavy Ion Research, where several chemical elements such as bohrium (1981), meitnerium (1982), hassium (1984), darmstadtium (1994), roentgenium (1994), and copernicium (1996) were discovered. The existence of the following elements were also confirmed at GSI Centre for Heavy Ion Research: nihonium (2012), flerovium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippuric Acid
Hippuric acid ( Gr. ''hippos'', horse, ''ouron'', urine) is a carboxylic acid and organic compound. It is found in urine and is formed from the combination of benzoic acid and glycine. Levels of hippuric acid rise with the consumption of phenolic compounds (such as fruit juice, tea and wine). The phenols are first converted to benzoic acid, and then to hippuric acid and excreted in urine. Hippuric acid crystallizes in rhombic prisms which are readily soluble in hot water, melt at 187 °C, and decompose at about 240 °C. High concentrations of hippuric acid may also indicate a toluene intoxication; however, scientists have called this correlation into question because there are other variables that affect levels of hippuric acid. When many aromatic compounds such as benzoic acid and toluene are taken internally, they are converted to hippuric acid by reaction with the amino acid, glycine. Synthesis A modern synthesis of hippuric acid involves the acylation of glyci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bavaria
Bavaria ( ; ), officially the Free State of Bavaria (german: Freistaat Bayern, link=no ), is a state in the south-east of Germany. With an area of , Bavaria is the largest German state by land area, comprising roughly a fifth of the total land area of Germany. With over 13 million inhabitants, it is second in population only to North Rhine-Westphalia, but due to its large size its population density is below the German average. Bavaria's main cities are Munich (its capital and largest city and also the third largest city in Germany), Nuremberg, and Augsburg. The history of Bavaria includes its earliest settlement by Iron Age Celtic tribes, followed by the conquests of the Roman Empire in the 1st century BC, when the territory was incorporated into the provinces of Raetia and Noricum. It became the Duchy of Bavaria (a stem duchy) in the 6th century AD following the collapse of the Western Roman Empire. It was later incorporated into the Holy Roman Empire, bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berchtesgaden
Berchtesgaden () is a municipality in the district Berchtesgadener Land, Bavaria, in southeastern Germany, near the border with Austria, south of Salzburg and southeast of Munich. It lies in the Berchtesgaden Alps, south of Berchtesgaden; the Berchtesgaden National Park stretches along three parallel valleys. The Kehlstein mountain (), with its '' Kehlsteinhaus'' (Eagle's Nest) is located in the area. Etymology ''Berchtesgaden'', Upper Bavaria (Achental), earlier ''Perchterscadmen'', ''Perhtersgadem'', ''Berchirchsgadem'', ''Berchtoldesgadem''; the word underwent a Latin distortion of Old High German ''parach'', Romance ''bareca'' 'hay shed'. After the basic meaning was forgotten, a variant word of Old High German ''gadem'' 'room, one-room hut' was added, implying the same meaning: 'hay shed'. Cf. Old High German ''muosgadem'' 'spice room'. There was a folk etymology that supported a derivation based on the legendary figure of ''Frau'' Perchta (Berchta), a woman (''Holle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thallium
Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861, in residues of sulfuric acid production. Both used the newly developed method of flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, from Greek , , meaning "green shoot" or "twig", was named by Crookes. It was isolated by both Lamy and Crookes in 1862; Lamy by electrolysis, and Crookes by precipitation and melting of the resultant powder. Crookes exhibited it as a powder precipitated by zinc at the international exhibition, which opened on 1 May that year. Thallium tends to form the +3 and +1 oxidation states. The +3 state resembles that of the other elements in group 13 ( boron, aluminium, gallium, indium). However, the +1 state, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theobromine
Theobromine, also known as xantheose, is the principal alkaloid of '' Theobroma cacao'' (cacao plant). Theobromine is slightly water- soluble (330 mg/L) with a bitter taste. In industry, theobromine is used as an additive and precursor to some cosmetics. It is found in chocolate, as well as in a number of other foods, including the leaves of the tea plant, and the kola nut. It is a white or colourless solid, but commercial samples can appear yellowish. Structure Theobromine is a flat molecule, a derivative of purine. It is also classified as a dimethyl xanthine. Related compounds include theophylline, caffeine, paraxanthine, and 7-methylxanthine, each of which differ in the number or placement of the methyl groups. History Theobromine was first discovered in 1841 in cacao beans by Russian chemist Aleksandr Voskresensky. Synthesis of theobromine from xanthine was first reported in 1882 by Hermann Emil Fischer. Etymology ''Theobromine'' is derived from '' Theobroma' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caffeine
Caffeine is a central nervous system (CNS) stimulant of the methylxanthine chemical classification, class. It is mainly recreational drug use, used recreationally as a Nootropic, cognitive enhancer, increasing alertness and attentional performance. Caffeine acts by blocking binding of adenosine to the adenosine A1 receptor, which enhances release of the neurotransmitter acetylcholine. Caffeine has a three-dimensional structure similar to that of adenosine, which allows it to bind and block its receptors. Caffeine also increases Cyclic adenosine monophosphate, cyclic AMP levels through nonselective inhibition of phosphodiesterase. Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is chemically related to the adenine and guanine nucleobase, bases of DNA, deoxyribonucleic acid (DNA) and RNA, ribonucleic acid (RNA). It is found in the seeds, fruits, nuts, or leaves of a number of plants native to Africa, East Asia and South America, and helps to prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xanthine
Xanthine ( or ; archaically xanthic acid; systematic name 3,7-dihydropurine-2,6-dione) is a purine base found in most human body tissues and fluids, as well as in other organisms. Several stimulants are derived from xanthine, including caffeine, theophylline, and theobromine. Xanthine is a product on the pathway of purine degradation. * It is created from guanine by guanine deaminase. * It is created from hypoxanthine by xanthine oxidoreductase. * It is also created from xanthosine by purine nucleoside phosphorylase. Xanthine is subsequently converted to uric acid by the action of the xanthine oxidase enzyme. Use and manufacturing Xanthine is used as a drug precursor for human and animal medications, and is manufactured as a pesticide ingredient. Clinical significance Derivatives of xanthine (known collectively as xanthines) are a group of alkaloids commonly used for their effects as mild stimulants and as bronchodilators, notably in the treatment of asthma or influ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guanine
Guanine () ( symbol G or Gua) is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine ( uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside is called guanosine. With the formula C5H5N5O, guanine is a derivative of purine, consisting of a fused pyrimidine- imidazole ring system with conjugated double bonds. This unsaturated arrangement means the bicyclic molecule is planar. Properties Guanine, along with adenine and cytosine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA, and uracil only in RNA. Guanine has two tautomeric forms, the major keto form (see figures) and rare enol form. It binds to cytosine through three hydrogen bonds. In cytosine, the amino group acts as the hydrogen bond donor and the C-2 carbonyl and the N-3 amine as the hydrogen-bond acceptors. Guanine has the C-6 carbonyl group that acts as the hydrogen bond acceptor, while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christian Gottlob Gmelin
Christian Gottlob Gmelin (12 October 1792 – 13 May 1860) was a German chemist. He was born in Tübingen, Germany, and was a grandson of Johann Konrad Gmelin and a great-grandson of Johann Georg Gmelin. Scientific career In 1818, Gmelin was one of the first to observe that lithium salts give a bright red color in a flame. In 1826, Jean-Baptiste Guimet was credited with having devised a process for the artificial manufacture of ultramarine. Two years later, in 1828, Gmelin published his own process for the artificial manufacture of ultramarine. Since Gmelin was the first to publish this process, he received the recognition for this discovery. In his publication, Gmelin stated that silica, alumina, and soda are the main constituents of ultramarine and the rich color comes from sulfur. Death Gmelin died in Tübingen, Germany, where he spent his entire life, on May 13, 1860. Works * ''Einleitung in die Chemie'' . Vol.1&2 . Laupp, Thüringen 1835-183Digital editionby the Universit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Berlin
Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative of Wilhelm von Humboldt, Johann Gottlieb Fichte and Friedrich Ernst Daniel Schleiermacher as the University of Berlin () in 1809, and opened in 1810, making it the oldest of Berlin's four universities. From 1828 until its closure in 1945, it was named Friedrich Wilhelm University (german: Friedrich-Wilhelms-Universität). During the Cold War, the university found itself in East Berlin and was ''de facto'' split in two when the Free University of Berlin opened in West Berlin. The university received its current name in honour of Alexander and Wilhelm von Humboldt in 1949. The university is divided into nine faculties including its medical school shared with the Freie Universität Berlin. The university has a student enrollment of aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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