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Oenology – study of all aspects of wine and winemaking.
Oenology (enology in American English; pronounced/iːˈnɒlədʒi/ee-nol-o-jee) is the science and study of all aspects of wine and winemaking except vine-growing andgrape-harvesting, which form a subfield called viticulture. "Viticulture and oenology" is a common designation for training programmes and research centres that include both the "outdoors" and "indoors" aspects of wine production. An expert in the field of oenology is known as an oenologist. The word oenology is derived from the Ancient Greek wordοἶνος (oinos, "wine") and the suffix -λογία (-logia, "study of").
The database, originally known as StARlite, was developed by a biotechnology company called Inpharmatica Ltd. later acquired by Galapagos NV. The data was acquired for EMBL in 2008 with an award from TheWellcome Trust, resulting in the creation of the ChEMBL chemogenomics group at EMBL-EBI, led by John Overington.
myChEMBL, the ChEMBL virtual machine, was released in October 2013 to allow users to access a complete and free, easy-to-install cheminformatics infrastructure.
In December 2013, the operations of the SureChem patent informatics database were transferred to EMBL-EBI. In a portmanteau, SureChem was renamed SureChEMBL.
2014 saw the introduction of the new resource ADME SARfari - a tool for predicting and comparing cross-species ADME targets.
Caffeine is a central nervous system (CNS) stimulant of the methylxanthineclass. It is the world's most widely consumed psychoactive drug, but — unlike many other psychoactive substances — it is legal and unregulated in nearly all parts of the world. There are several known mechanisms of action to explain the effects of caffeine. The most prominent is that it reversibly blocks the action of adenosine on its receptor and consequently prevents the onset of drowsiness induced by adenosine. Caffeine also stimulates certain portions of the autonomic nervous system.
Caffeine
Chemical identification, isolation, and synthesis
Pierre Joseph Pelletier
In 1819, the German chemist Friedlieb Ferdinand Rungeisolated relatively pure caffeine for the first time; he called it "Kaffebase" (i.e. a base that exists in coffee).According to Runge, he did this at the behest of Johann Wolfgang von Goethe. In 1821, caffeine was isolated both by the French chemist Pierre Jean Robiquet and by another pair of French chemists, Pierre-Joseph Pelletierand Joseph Bienaimé Caventou, according to Swedish chemist Jöns Jacob Berzelius in his yearly journal. Furthermore, Berzelius stated that the French chemists had made their discoveries independently of any knowledge of Runge's or each other's work. However, Berzelius later acknowledged Runge's priority in the extraction of caffeine, stating: "However, at this point, it should not remain unmentioned that Runge (in his Phytochemical Discoveries, 1820, pages 146–147) specified the same method and described caffeine under the name Caffeebase a year earlier than Robiquet, to whom the discovery of this substance is usually attributed, having made the first oral announcement about it at a meeting of the Pharmacy Society in Paris."
Pelletier's article on caffeine was the first to use the term in print (in the French form Caféine from the French word for coffee: café). It corroborates Berzelius's account:
Caffeine, noun (feminine). Crystallizable substance discovered in coffee in 1821 by Mr. Robiquet. During the same period – while they were searching for quinine in coffee because coffee is considered by several doctors to be a medicine that reduces fevers and because coffee belongs to the same family as the cinchona [quinine] tree – on their part, Messrs. Pelletier and Caventou obtained caffeine; but because their research had a different goal and because their research had not been finished, they left priority on this subject to Mr. Robiquet. We do not know why Mr. Robiquet has not published the analysis of coffee which he read to the Pharmacy Society. Its publication would have allowed us to make caffeine better known and give us accurate ideas of coffee's composition ...
Robiquet was one of the first to isolate and describe the properties of pure caffeine,whereas Pelletier was the first to perform an elemental analysis.
In 1827, M. Oudry isolated "théine" from tea, but it was later proved by Mulder and by Carl Jobst that theine was actually caffeine.
In 1895, German chemist Hermann Emil Fischer (1852–1919) first synthesized caffeine from its chemical components (i.e. a "total synthesis"), and two years later, he also derived the structural formula of the compound. This was part of the work for which Fischer was awarded the Nobel Prize in 1902.
Chemical properties
Thexanthinecore of caffeine contains two fused rings, apyrimidinedioneandimidazole. The pyrimidinedione in turn contains twoamidefunctional groups that exist predominately in azwitterionicresonancethe location from which the nitrogen atoms are double bonded to their adjacent amide carbons atoms. Hence all six of the atoms within the pyrimidinedione ring system are sp2hybridizedand planar. Therefore, the fused 5,6 ring core of caffeine contains a total of tenpi electronsand hence according toHückel's ruleisaromatic.
Biosynthesis
Caffeine may be synthesized from dimethylurea and malonic acid, but is rarely obtained from synthesis since it is readily available as a byproduct of decaffeination.
Extraction of caffeine from coffee, to produce caffeine and decaffeinated coffee, can be performed using a number of solvents.Benzene, chloroform, trichloroethylene, anddichloromethane have all been used over the years but for reasons of safety, environmental impact, cost, and flavor, they have been superseded by the following main methods:
Water extraction: Coffee beans are soaked in water. The water, which contains many other compounds in addition to caffeine and contributes to the flavor of coffee, is then passed through activated charcoal, which removes the caffeine. The water can then be put back with the beans and evaporated dry, leaving decaffeinated coffee with its original flavor. Coffee manufacturers recover the caffeine and resell it for use in soft drinks and over-the-counter caffeine tablets.
Supercritical carbon dioxide extraction:Supercritical carbon dioxide is an excellent nonpolar solvent for caffeine, and is safer than the organic solvents that are otherwise used. The extraction process is simple: CO2 is forced through the green coffee beans at temperatures above 31.1 °C and pressures above 73 atm. Under these conditions, CO2 is in a "supercritical" state: It has gaslike properties that allow it to penetrate deep into the beans but also liquid-like properties that dissolve 97–99% of the caffeine. The caffeine-laden CO2 is then sprayed with high pressure water to remove the caffeine. The caffeine can then be isolated bycharcoaladsorption (as above) or by distillation, recrystallization, or reverse osmosis.
Extraction by organic solvents: Certain organic solvents such as ethyl acetatepresent much less health and environmental hazard than chlorinated and aromatic organic solvents used formerly. Another method is to use triglyceride oils obtained from spent coffee grounds.
"Decaffeinated" coffees do in fact contain caffeine in many cases — some commercially available decaffeinated coffee products contain considerable levels. One study found that decaffeinated coffee contained 10 mg of caffeine per cup, compared to approximately 85 mg of caffeine per cup for regular coffee.
Analogs
Some analog substances have been created which mimic caffeine's properties with either function or structure or both. Of the latter group are the xanthinesDMPX and 8-chlorotheophylline, which is an ingredient in dramamine. Members of a class of nitrogen substituted xanthines are often proposed as potential alternatives to caffeine. Many other xanthine analogues constituting the adenosine receptor antagonist class have also been elucidated.
Xanthine (/ˈzænθiːn/ or /ˈzænθaɪn/; archaically xanthic acid) (3,7-dihydro-purine-2,6-dione), is a purinebasefound in most human body tissues and fluids and in other organisms. A number of stimulants are derived from xanthine, including caffeine and theobromine.
DMPX (3,7-Dimethyl-1-propargylxanthine) is a caffeineanalog which displays affinity to A2-adenosine receptors, in contrast to the A1 subtype receptors. DMPX had 28× & 15× higher potency than caffeine in blocking peripheral and central NECA-responses. The locomotor stimulation caused by DMPX (ED50 10 μmol/kg) was similarly higher than caffeine.
8-Chlorotheophylline, also known as1,3-dimethyl-8-chloroxanthine, is astimulantdrug of the xanthine chemical class, with physiological effects similar to caffeine. It is combined with pharmaceutical drugs to form stable salts, such as theantiemeticdimenhydrinate, which is broken down intodiphenhydramine, the active antiemetic, and 8-Chlorotheophylline, to ward off drowsiness.
Dimenhydrinate (marketed as Dramamine, Gravol and many other brand names) is an over-the-counterantiemetic used for the treatment of the symptoms of motion sickness. It is most commonly prepared as tablets, although it is also available in liquid form and insuppositories. Dimenhydrinate is a combination of two drugs:diphenhydramine and 8-chlorotheophylline.
In mathematics and computer science, graph theory is the study of graphs, which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of vertices, nodes, or points which are connected by edges, arcs, or lines. A graph may be undirected, meaning that there is no distinction between the two vertices associated with each edge, or its edges may be directed from one vertex to another; see Graph (discrete mathematics)for more detailed definitions and for other variations in the types of graph that are commonly considered. Graphs are one of the prime objects of study in discrete mathematics.
Graph theory is also used to study molecules in chemistry and physics. In condensed matter physics, the three-dimensional structure of complicated simulated atomic structures can be studied quantitatively by gathering statistics on graph-theoretic properties related to the topology of the atoms. In chemistry a graph makes a natural model for a molecule, where vertices represent atoms and edges bonds. This approach is especially used in computer processing of molecular structures, ranging from chemical editors to database searching. In statistical physics, graphs can represent local connections between interacting parts of a system, as well as the dynamics of a physical process on such systems. Similarly, in computational neuroscience graphs can be used to represent functional connections between brain areas that interact to give rise to various cognitive processes, where the vertices represent different areas of the brain and the edges represent the connections between those areas. Graphs are also used to represent the micro-scale channels of porous media, in which the vertices represent the pores and the edges represent the smaller channels connecting the pores.
The Königsberg Bridge problem
The paper written by Leonhard Euler on the Seven Bridges of Königsberg and published in 1736 is regarded as the first paper in the history of graph theory. This paper, as well as the one written byVandermonde on the knight problem, carried on with the analysis situs initiated by Leibniz. Euler's formula relating the number of edges, vertices, and faces of a convex polyhedron was studied and generalized by Cauchy and L'Huillier, and represents the beginning of the branch of mathematics known as topology.
The Seven Bridges of Königsberg is a historically notable problem in mathematics. Its negative resolution by Leonhard Euler in 1736 laid the foundations of graph theory and prefigured the idea of topology.
A knight's tour is a sequence of moves of a knight on a chessboardsuch that the knight visits every square only once. If the knight ends on a square that is one knight's move from the beginning square (so that it could tour the board again immediately, following the same path), the tour is closed, otherwise it is open.
In mathematics, topology (from theGreek τόπος, place, and λόγος, study) is concerned with the properties of space that are preserved undercontinuous deformations, such as stretching and bending, but not tearing or gluing. This can be studied by considering a collection of subsets, called open sets, that satisfy certain properties, turning the given set into what is known as a topological space. Important topological properties include connectedness and compactness.
More than one century after Euler's paper on the bridges of Königsberg and while Listing was introducing the concept of topology, Cayley was led by an interest in particular analytical forms arising from differential calculus to study a particular class of graphs, the trees. This study had many implications for theoretical chemistry. The techniques he used mainly concern the enumeration of graphs with particular properties. Enumerative graph theory then arose from the results of Cayley and the fundamental results published by Pólya between 1935 and 1937. These were generalized by De Bruijn in 1959. Cayley linked his results on trees with contemporary studies of chemical composition. The fusion of ideas from mathematics with those from chemistry began what has become part of the standard terminology of graph theory.
In particular, the term "graph" was introduced by Sylvester in a paper published in 1878 in Nature, where he draws an analogy between "quantic invariants" and "co-variants" of algebra and molecular diagrams:
"[…] Every invariant and co-variant thus becomes expressible by a graphprecisely identical with a Kekuléan diagram or chemicograph. […] I give a rule for the geometrical multiplication of graphs, i.e. for constructing a graph to the product of in- or co-variants whose separate graphs are given. […]" (italics as in the original).
The first textbook on graph theory was written by Dénes Kőnig, and published in 1936. Another book by Frank Harary, published in 1969, was "considered the world over to be the definitive textbook on the subject", and enabled mathematicians, chemists, electrical engineers and social scientists to talk to each other. Harary donated all of the royalties to fund the Pólya Prize.
Johann Benedict Listing (25 July 1808 – 24 December 1882) was a German mathematician.
In mathematics, differential calculus is a subfield of calculus concerned with the study of the rates at which quantities change. It is one of the two traditional divisions of calculus, the other being integral calculus.
