1.
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
2.
ChEMBL
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ChEMBL or ChEMBLdb is a manually curated chemical database of bioactive molecules with drug-like properties. It is maintained by the European Bioinformatics Institute, of the European Molecular Biology Laboratory, based at the Wellcome Trust Genome Campus, Hinxton, 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 The Wellcome Trust, resulting in the creation of the ChEMBL chemogenomics group at EMBL-EBI, the ChEMBL database contains compound bioactivity data against drug targets. Bioactivity is reported in Ki, Kd, IC50, and EC50, data can be filtered and analyzed to develop compound screening libraries for lead identification during drug discovery. ChEMBL version 2 was launched in January 2010, including 2.4 million bioassay measurements covering 622,824 compounds and this was obtained from curating over 34,000 publications across twelve medicinal chemistry journals. ChEMBLs coverage of available bioactivity data has grown to become the most comprehensive ever seen in a public database, in October 2010 ChEMBL version 8 was launched, with over 2.97 million bioassay measurements covering 636,269 compounds. ChEMBL_10 saw the addition of the PubChem confirmatory assays, in order to integrate data that is comparable to the type, ChEMBLdb can be accessed via a web interface or downloaded by File Transfer Protocol. It is formatted in a manner amenable to computerized data mining, ChEMBL is also integrated into other large-scale chemistry resources, including PubChem and the ChemSpider system of the Royal Society of Chemistry. In addition to the database, the ChEMBL group have developed tools and these include Kinase SARfari, an integrated chemogenomics workbench focussed on kinases. The system incorporates and links sequence, structure, compounds and screening data, the primary purpose of ChEMBL-NTD is to provide a freely accessible and permanent archive and distribution centre for deposited data. July 2012 saw the release of a new data service, sponsored by the Medicines for Malaria Venture. The data in this service includes compounds from the Malaria Box screening set, 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
3.
ChemSpider
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ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses
4.
European Chemicals Agency
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ECHA is the driving force among regulatory authorities in implementing the EUs chemicals legislation. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and it is located in Helsinki, Finland. The Agency, headed by Executive Director Geert Dancet, started working on 1 June 2007, the REACH Regulation requires companies to provide information on the hazards, risks and safe use of chemical substances that they manufacture or import. Companies register this information with ECHA and it is freely available on their website. So far, thousands of the most hazardous and the most commonly used substances have been registered, the information is technical but gives detail on the impact of each chemical on people and the environment. This also gives European consumers the right to ask whether the goods they buy contain dangerous substances. The Classification, Labelling and Packaging Regulation introduces a globally harmonised system for classifying and labelling chemicals into the EU. This worldwide system makes it easier for workers and consumers to know the effects of chemicals, companies need to notify ECHA of the classification and labelling of their chemicals. So far, ECHA has received over 5 million notifications for more than 100000 substances, the information is freely available on their website. Consumers can check chemicals in the products they use, Biocidal products include, for example, insect repellents and disinfectants used in hospitals. The Biocidal Products Regulation ensures that there is information about these products so that consumers can use them safely. ECHA is responsible for implementing the regulation, the law on Prior Informed Consent sets guidelines for the export and import of hazardous chemicals. Through this mechanism, countries due to hazardous chemicals are informed in advance and have the possibility of rejecting their import. Substances that may have effects on human health and the environment are identified as Substances of Very High Concern 1. These are mainly substances which cause cancer, mutation or are toxic to reproduction as well as substances which persist in the body or the environment, other substances considered as SVHCs include, for example, endocrine disrupting chemicals. Companies manufacturing or importing articles containing these substances in a concentration above 0 and they are required to inform users about the presence of the substance and therefore how to use it safely. Consumers have the right to ask the retailer whether these substances are present in the products they buy, once a substance has been officially identified in the EU as being of very high concern, it will be added to a list. This list is available on ECHA’s website and shows consumers and industry which chemicals are identified as SVHCs, Substances placed on the Candidate List can then move to another list
5.
PubChem
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PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information, a component of the National Library of Medicine, PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be downloaded via FTP. PubChem contains substance descriptions and small molecules with fewer than 1000 atoms and 1000 bonds, more than 80 database vendors contribute to the growing PubChem database. PubChem consists of three dynamically growing primary databases, as of 28 January 2016, Compounds,82.6 million entries, contains pure and characterized chemical compounds. Substances,198 million entries, contains also mixtures, extracts, complexes, bioAssay, bioactivity results from 1.1 million high-throughput screening programs with several million values. PubChem contains its own online molecule editor with SMILES/SMARTS and InChI support that allows the import and export of all common chemical file formats to search for structures and fragments. In the text search form the database fields can be searched by adding the name in square brackets to the search term. A numeric range is represented by two separated by a colon. The search terms and field names are case-insensitive, parentheses and the logical operators AND, OR, and NOT can be used. AND is assumed if no operator is used, example,0,5000,50,10 -5,5 PubChem was released in 2004. The American Chemical Society has raised concerns about the publicly supported PubChem database and they have a strong interest in the issue since the Chemical Abstracts Service generates a large percentage of the societys revenue. To advocate their position against the PubChem database, ACS has actively lobbied the US Congress, soon after PubChems creation, the American Chemical Society lobbied U. S. Congress to restrict the operation of PubChem, which they asserted competes with their Chemical Abstracts Service
6.
International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL license, but it now uses a custom license called IUPAC-InChI Trust License. Not all layers have to be provided, for instance, the layer can be omitted if that type of information is not relevant to the particular application. InChIs can thus be seen as akin to a general and extremely formalized version of IUPAC names and they can express more information than the simpler SMILES notation and differ in that every structure has a unique InChI string, which is important in database applications. Information about the 3-dimensional coordinates of atoms is not represented in InChI, the InChI algorithm converts input structural information into a unique InChI identifier in a three-step process, normalization, canonicalization, and serialization. The InChIKey, sometimes referred to as a hashed InChI, is a fixed length condensed digital representation of the InChI that is not human-understandable. The InChIKey specification was released in September 2007 in order to facilitate web searches for chemical compounds and it should be noted that, unlike the InChI, the InChIKey is not unique, though collisions can be calculated to be very rare, they happen. In January 2009 the final 1.02 version of the InChI software was released and this provided a means to generate so called standard InChI, which does not allow for user selectable options in dealing with the stereochemistry and tautomeric layers of the InChI string. The standard InChIKey is then the hashed version of the standard InChI string, the standard InChI will simplify comparison of InChI strings and keys generated by different groups, and subsequently accessed via diverse sources such as databases and web resources. Every InChI starts with the string InChI= followed by the version number and this is followed by the letter S for standard InChIs. The remaining information is structured as a sequence of layers and sub-layers, the layers and sub-layers are separated by the delimiter / and start with a characteristic prefix letter. The six layers with important sublayers are, Main layer Chemical formula and this is the only sublayer that must occur in every InChI. The atoms in the formula are numbered in sequence, this sublayer describes which atoms are connected by bonds to which other ones. Describes how many hydrogen atoms are connected to each of the other atoms, the condensed,27 character standard InChIKey is a hashed version of the full standard InChI, designed to allow for easy web searches of chemical compounds. Most chemical structures on the Web up to 2007 have been represented as GIF files, the full InChI turned out to be too lengthy for easy searching, and therefore the InChIKey was developed. With all databases currently having below 50 million structures, such duplication appears unlikely at present, a recent study more extensively studies the collision rate finding that the experimental collision rate is in agreement with the theoretical expectations. Example, Morphine has the structure shown on the right, as the InChI cannot be reconstructed from the InChIKey, an InChIKey always needs to be linked to the original InChI to get back to the original structure
7.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES
8.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH
9.
Odor
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An odor or odour or fragrance is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors, the terms fragrance and aroma are used primarily by the food and cosmetic industry to describe a pleasant odor, and are sometimes used to refer to perfumes, and to describe floral scent. In contrast, malodor, stench, reek, and stink are used specifically to describe unpleasant odor, the term smell is used for both pleasant and unpleasant odors. In the United Kingdom, odour refers to scents in general, the sense of smell gives rise to the perception of odors, mediated by the olfactory nerve. The olfactory receptor cells are present in the olfactory epithelium. There are millions of olfactory receptor neurons that act as sensory signaling cells, each neuron has cilia in direct contact with air. The olfactory nerve is considered the smell mediator, the axon connects the brain to the external air, odorous molecules act as a chemical stimulus. Molecules bind to receptor proteins extended from cilia, initiating an electric signal, thus, by using a chemical that binds to copper in the mouse nose, so that copper wasn’t available to the receptors, the authors showed that the mice couldnt detect the thiols. However, these also found that MOR244-3 lacks the specific metal ion binding site suggested by Suslick. When the signal reaches a threshold, the fires, sending a signal traveling along the axon to the olfactory bulb. Interpretation of the begins, relating the smell to past experiences. The olfactory bulb acts as a station connecting the nose to the olfactory cortex in the brain. Olfactory information is processed and projected through a pathway to the central nervous system. Odor sensation usually depends on the concentration available to the olfactory receptors, the olfactory system does not interpret a single compound, but instead the whole odorous mix, not necessarily corresponding to concentration or intensity of any single constituent. The widest range of odors consists of compounds, although some simple compounds not containing carbon, such as hydrogen sulfide. The perception of an effect is a two-step process. First, there is the part, the detection of stimuli by receptors in the nose. The stimuli are processed by the region of the brain which is responsible for olfaction
10.
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
11.
Boiling point
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The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the environmental pressure. A liquid in a vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at high pressure has a boiling point than when that liquid is at atmospheric pressure. For a given pressure, different liquids boil at different temperatures, for example, water boils at 100 °C at sea level, but at 93.4 °C at 2,000 metres altitude. The normal boiling point of a liquid is the case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level,1 atmosphere. At that temperature, the pressure of the liquid becomes sufficient to overcome atmospheric pressure. The standard boiling point has been defined by IUPAC since 1982 as the temperature at which boiling occurs under a pressure of 1 bar, the heat of vaporization is the energy required to transform a given quantity of a substance from a liquid into a gas at a given pressure. Liquids may change to a vapor at temperatures below their boiling points through the process of evaporation, evaporation is a surface phenomenon in which molecules located near the liquids edge, not contained by enough liquid pressure on that side, escape into the surroundings as vapor. On the other hand, boiling is a process in which molecules anywhere in the liquid escape, a saturated liquid contains as much thermal energy as it can without boiling. The saturation temperature is the temperature for a corresponding saturation pressure at which a liquid boils into its vapor phase, the liquid can be said to be saturated with thermal energy. Any addition of energy results in a phase transition. If the pressure in a system remains constant, a vapor at saturation temperature will begin to condense into its liquid phase as thermal energy is removed, similarly, a liquid at saturation temperature and pressure will boil into its vapor phase as additional thermal energy is applied. The boiling point corresponds to the temperature at which the pressure of the liquid equals the surrounding environmental pressure. Thus, the point is dependent on the pressure. Boiling points may be published with respect to the NIST, USA standard pressure of 101.325 kPa, at higher elevations, where the atmospheric pressure is much lower, the boiling point is also lower. The boiling point increases with increased pressure up to the critical point, the boiling point cannot be increased beyond the critical point. Likewise, the point decreases with decreasing pressure until the triple point is reached
12.
Aqueous solution
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An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending to the relevant chemical formula, for example, a solution of table salt, or sodium chloride, in water would be represented as Na+ + Cl−. The word aqueous means pertaining to, related to, similar to, as water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Substances that are hydrophobic often do not dissolve well in water, an example of a hydrophilic substance is sodium chloride. Acids and bases are aqueous solutions, as part of their Arrhenius definitions, the ability of a substance to dissolve in water is determined by whether the substance can match or exceed the strong attractive forces that water molecules generate between themselves. If the substance lacks the ability to dissolve in water the molecules form a precipitate, reactions in aqueous solutions are usually metathesis reactions. Metathesis reactions are another term for double-displacement, that is, when a cation displaces to form a bond with the other anion. The cation bonded with the latter anion will dissociate and bond with the other anion, aqueous solutions that conduct electric current efficiently contain strong electrolytes, while ones that conduct poorly are considered to have weak electrolytes. Those strong electrolytes are substances that are ionized in water. Nonelectrolytes are substances that dissolve in water yet maintain their molecular integrity, examples include sugar, urea, glycerol, and methylsulfonylmethane. When writing the equations of reactions, it is essential to determine the precipitate. To determine the precipitate, one must consult a chart of solubility, soluble compounds are aqueous, while insoluble compounds are the precipitate. Remember that there may not always be a precipitate, when performing calculations regarding the reacting of one or more aqueous solutions, in general one must know the concentration, or molarity, of the aqueous solutions. Solution concentration is given in terms of the form of the prior to it dissolving. Metal ions in aqueous solution Solubility Dissociation Acid-base reaction theories Properties of water Zumdahl S.1997, 4th ed. Boston, Houghton Mifflin Company
13.
Solubility
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Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent. The solubility of a substance depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure. The solubility of a substance is a different property from the rate of solution. Most often, the solvent is a liquid, which can be a substance or a mixture. One may also speak of solid solution, but rarely of solution in a gas, the extent of solubility ranges widely, from infinitely soluble such as ethanol in water, to poorly soluble, such as silver chloride in water. The term insoluble is often applied to poorly or very poorly soluble compounds, a common threshold to describe something as insoluble is less than 0.1 g per 100 mL of solvent. Under certain conditions, the solubility can be exceeded to give a so-called supersaturated solution. Metastability of crystals can also lead to apparent differences in the amount of a chemical that dissolves depending on its form or particle size. A supersaturated solution generally crystallises when seed crystals are introduced and rapid equilibration occurs, phenylsalicylate is one such simple observable substance when fully melted and then cooled below its fusion point. Solubility is not to be confused with the ability to dissolve a substance, for example, zinc dissolves in hydrochloric acid as a result of a chemical reaction releasing hydrogen gas in a displacement reaction. The zinc ions are soluble in the acid, the smaller a particle is, the faster it dissolves although there are many factors to add to this generalization. Crucially solubility applies to all areas of chemistry, geochemistry, inorganic, physical, organic, in all cases it will depend on the physical conditions and the enthalpy and entropy directly relating to the solvents and solutes concerned. By far the most common solvent in chemistry is water which is a solvent for most ionic compounds as well as a range of organic substances. This is a factor in acidity/alkalinity and much environmental and geochemical work. According to the IUPAC definition, solubility is the composition of a saturated solution expressed as a proportion of a designated solute in a designated solvent. Solubility may be stated in units of concentration such as molarity, molality, mole fraction, mole ratio, mass per volume. Solubility occurs under dynamic equilibrium, which means that solubility results from the simultaneous and opposing processes of dissolution, the solubility equilibrium occurs when the two processes proceed at a constant rate. The term solubility is used in some fields where the solute is altered by solvolysis
14.
Occupational safety and health
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These terms of course also refer to the goals of this field, so their use in the sense of this article was originally an abbreviation of occupational safety and health program/department etc. The goals of occupational safety and health programs include to foster a safe, OSH may also protect co-workers, family members, employers, customers, and many others who might be affected by the workplace environment. In the United States, the occupational health and safety is referred to as occupational health and occupational and non-occupational safety. In common-law jurisdictions, employers have a common law duty to take care of the safety of their employees. As defined by the World Health Organization occupational health deals with all aspects of health, Health has been defined as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. Occupational health is a field of healthcare concerned with enabling an individual to undertake their occupation. Health has been defined as It contrasts, for example, with the promotion of health and safety at work, since 1950, the International Labour Organization and the World Health Organization have shared a common definition of occupational health. It was adopted by the Joint ILO/WHO Committee on Occupational Health at its first session in 1950, the concept of working culture is intended in this context to mean a reflection of the essential value systems adopted by the undertaking concerned. Such a culture is reflected in practice in the systems, personnel policy, principles for participation, training policies. Professionals advise on a range of occupational health matters. The research and regulation of safety and health are a relatively recent phenomenon. As labor movements arose in response to concerns in the wake of the industrial revolution. The initial remit of the Inspectorate was to police restrictions on the hours in the textile industry of children. The commission sparked public outrage resulted in the Mines Act of 1842. Otto von Bismarck inaugurated the first social insurance legislation in 1883, similar acts followed in other countries, partly in response to labor unrest. Although work provides many economic and other benefits, an array of workplace hazards also present risks to the health. Personal protective equipment can protect against many of these hazards. Physical hazards affect many people in the workplace, Falls are also a common cause of occupational injuries and fatalities, especially in construction, extraction, transportation, healthcare, and building cleaning and maintenance
15.
Preservative
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In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compounds to the product, physical preservation entails processes such as refrigeration or drying. Preservative food additives reduce the risk of infections, decrease microbial spoilage. Some physical techniques for preservation include dehydration, UV-C radiation, freeze-drying. Chemical preservation and physical preservation techniques are sometimes combined, antimicrobial preservatives prevent degradation by bacteria. This method is the most traditional and ancient type of preserving—ancient methods such as pickling and adding honey prevent microorganism growth by modifying the pH level, the most commonly used antimicrobial preservative is lactic acid. Common antimicrobial preservatives are presented in the table, nitrates and nitrites are also antimicrobial. The detailed mechanism of chemical compounds range from inhibiting growth of the bacteria to the inhibition of specific enzymes. The oxidation process spoils most food, especially those with a fat content. Fats quickly turn rancid when exposed to oxygen, antioxidants prevent or inhibit the oxidation process. The most common antioxidant additives are ascorbic acid and ascorbates, thus, antioxidants are commonly added to oils, cheese, and chips. Other antioxidants include the phenol derivatives BHA, BHT, TBHQ and these agents suppress the formation of hydroperoxides. Other preservatives include ethanol and methylchloroisothiazolinone, a variety of agents are added to sequester metal ions that otherwise catalyze the oxidation of fats. Common sequestering agents are disodium EDTA, citric acid, tartaric acid, citric and ascorbic acids target enzymes that degrade fruits and vegetables, e. g. phenolase which turns surfaces of cut apples and potatoes brown. Ascorbic acid and tocopherol, which are vitamins, are common preservatives, smoking entails exposing food to a variety of phenols, which are antioxidants. Natural preservatives include rosemary extract, hops, salt, sugar, vinegar, alcohol, diatomaceous earth, traditional preservatives, such as sodium benzoate have raised health concerns in the past. Benzoate was shown in a study to cause hypersensitivity in some asthma sufferers and this has caused reexamination of natural preservatives which occur in vegetables. Preservatives have been used since prehistoric times, smoked meat for example has phenols and other chemicals that retard spoilage
16.
Hypnotic
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This group is related to sedatives. Whereas the term sedative describes drugs that serve to calm or relieve anxiety, because these two functions frequently overlap, and because drugs in this class generally produce dose-dependent effects they are often referred to collectively as sedative-hypnotic drugs. Hypnotic drugs are prescribed for insomnia and other sleep disorders. When prescribed, hypnotic medication should be used for the shortest period of time necessary, most hypnotics prescribed today are either benzodiazepines or nonbenzodiazepines. Among individuals with sleep disorders,13. 7% are taking or prescribed nonbenzodiazepines, while 10. 8% are taking benzodiazepines, early classes of drugs, such as barbiturates, have fallen out of use in most practices but are still prescribed for some patients. In children, prescribing hypnotics is not yet acceptable unless used to treat night terrors or somnambulism, falling outside of the above-mentioned categories, the neuro-hormone melatonin has a hypnotic function. Research about using medications to treat insomnia evolved throughout the last half of the 20th century, treatment for insomnia in psychiatry dates back to 1869 when chloral hydrate was first used as a soporific. Barbiturates emerged as the first class of drugs that emerged in the early 1900s, although the best drug family at the time they were dangerous in overdose. During the 1970s, quinazolinones and benzodiazepines were introduced as alternatives to replace barbiturates. Benzodiazepines are not without their drawbacks, substance dependence is possible, questions have been raised as to whether they disturb sleep architecture. Nonbenzodiazepines are the most recent development, although its clear that they are less toxic than their predecessors, barbiturates, comparative efficacy over benzodiazepines have not been established. Without longitudinal studies, it is hard to determine, however some psychiatrists recommend these drugs, other sleep remedies that may be considered sedative-hypnotics exist, psychiatrists will sometimes prescribe medicines off-label if they have sedating effects. Examples of these include mirtazapine, clonidine, quetiapine, and the over-the-counter sleep aid diphenhydramine, off-label sleep remedies are particularly useful when first-line treatment is unsuccessful or deemed unsafe. Barbiturates are drugs that act as central nervous system depressants, and can produce a wide spectrum of effects. They are also effective as anxiolytics, hypnotics, and anticonvulsants, barbiturates also have analgesic effects, however, these effects are somewhat weak, preventing barbiturates from being used in surgery in the absence of other analgesics. They have dependence liability, both physical and psychological, however, barbiturates are still used in general anesthesia, for epilepsy, and assisted suicide. Barbiturates are derivatives of barbituric acid, the principal mechanism of action of barbiturates is believed to be positive allosteric modulation of GABAA receptors. Examples include amobarbital, pentobarbital, phenobarbital, secobarbital, and sodium thiopental, quinazolinones are also a class of drugs which function as hypnotic/sedatives that contain a 4-quinazolinone core
17.
Local anesthetic
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A local anesthetic is a medication that causes reversible absence of pain sensation, although other senses are often affected, as well. Also, when it is used on specific nerve pathways, paralysis also can be achieved, clinical LAs belong to one of two classes, aminoamide and aminoester local anesthetics. Synthetic LAs are structurally related to cocaine and they differ from cocaine mainly in that they have a very low abuse potential and do not produce hypertension or vasoconstriction. In a medical setting, pain alleviation is desired when its function is no longer needed. Besides improving patient comfort, pain therapy can also reduce harmful physiological consequences of untreated pain, acute pain can often be managed using analgesics. However, conduction anesthesia may be preferable because of pain control. For purposes of pain therapy, LA drugs are given by repeated injection or continuous infusion through a catheter. Low doses of LA drugs can be sufficient so that muscle weakness does not occur, LAs can be applied repeatedly or continuously for prolonged periods to relieve chronic pain, usually in combination with medication such as opioids, NSAIDs, and anticonvulsants. Virtually every part of the body can be anesthetized using conduction anesthesia, however, only a limited number of techniques are in common clinical use. Sometimes, conduction anesthesia is combined with general anesthesia or sedation for the patients comfort and it may also be suitable for other kinds of punctures such as ascites drainage and amniocentesis. Surface anesthesia also facilitates some endoscopic procedures such as bronchoscopy or cystoscopy, the local adverse effects of anesthetic agents include neurovascular manifestations such as prolonged anesthesia and paresthesia. These are symptoms of localized nerve impairment or nerve damage, of particular note, the use of topical anesthetics for relief of eye pain can result in severe corneal damage. The risk of temporary or permanent nerve damage varies between different locations and types of nerve blocks, permanent nerve damage after a peripheral nerve block is rare. Symptoms are likely to resolve within a few weeks, the vast majority of those affected recover within four to six weeks, 99% of these people have recovered within a year. An estimated one in 5,000 to 30,000 nerve blocks results in degree of permanent persistent nerve damage. Symptoms may continue to improve for up to 18 months following injury, the conduction of electric impulses follows a similar mechanism in peripheral nerves, the central nervous system, and the heart. The effects of local anesthetics are, therefore, not specific for the conduction in peripheral nerves. Side effects on the nervous system and the heart may be severe
18.
Chloral hydrate
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Chloral hydrate is an geminal diol with the formula C2H3Cl3O2. It has limited use as a sedative and hypnotic pharmaceutical drug and it is also a useful laboratory chemical reagent and precursor. It is derived from chloral by the addition of one equivalent of water and it was discovered through the chlorination of ethanol in 1832 by Justus von Liebig in Gießen. Its sedative properties were first published in 1869 and subsequently, because of its easy synthesis and it was widely used recreationally and misprescribed in the late 19th century. Chloral hydrate is soluble in water and ethanol, readily forming concentrated solutions. A solution of chloral hydrate in ethanol called knockout drops was used to prepare a Mickey Finn, because of its status as a regulated substance, chloral hydrate can be difficult to obtain. This has led to chloral hydrate being replaced by reagents in microscopy procedures. It is, together with chloroform, a minor side-product of the chlorination of water when organic residues such as humic acids are present and it has been detected in drinking water at concentrations of up to 100 micrograms per litre but concentrations are normally found to be below 10 µg/L. Levels are generally found to be higher in surface water than in ground water, usage of the drug as a sedative or hypnotic may carry some risk given the lack of clinical trials. Chloral hydrate is used for the treatment of insomnia and as a sedative before minor medical or dental treatment. It was largely displaced in the century by barbiturates and subsequently by benzodiazepines. It was also used in veterinary medicine as a general anesthetic. It is also used as a sedative prior to EEG procedures. In therapeutic doses for insomnia, chloral hydrate is effective within 20 to 60 minutes, in humans it is metabolized within 7 hours into trichloroethanol and trichloroethanol glucuronide by erythrocytes and plasma esterases and into trichloroacetic acid in 4 to 5 days. It has a narrow therapeutic window making this drug difficult to use. Higher doses can depress respiration and blood pressure, Chloral hydrate is a starting point for the synthesis of other organic compounds. It is the material for the production of chloral, which is produced by the distillation of a mixture of chloral hydrate and sulfuric acid. Notably, it is used to synthesize isatin, prolonged exposure to the vapors is unhealthy however, with a LD50 for 4-hour exposure of 440 mg/m3
19.
Menthol
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Menthol is an organic compound made synthetically or obtained from corn mint, peppermint, or other mint oils. It is a waxy, crystalline substance, clear or white in color, the main form of menthol occurring in nature is -menthol, which is assigned the configuration. Menthol has local anesthetic and counterirritant qualities, and it is used to relieve minor throat irritation. Menthol also acts as a kappa opioid receptor agonist. Natural menthol exists as one pure stereoisomer, nearly always the form, the eight possible stereoisomers are, In the natural compound, the isopropyl group is in the trans orientation to both the methyl and hydroxyl groups. Thus, it can be drawn in any of the ways shown, The -, with the ring itself in a chair conformation, all three bulky groups can orient in equatorial positions. The two crystal forms for racemic menthol have melting points of 28 °C and 38 °C, pure -menthol has four crystal forms, of which the most stable is the α form, the familiar broad needles. Menthols ability to trigger the cold-sensitive TRPM8 receptors in the skin is responsible for the well-known cooling sensation it provokes when inhaled, eaten. In this sense, it is similar to capsaicin, the responsible for the spiciness of hot chilis. Menthols analgesic properties are mediated through an activation of κ-opioid receptors. Menthol also blocks sodium channels, reducing neural activity that may stimulate muscles. A study showed that absorption of ibuprofen is not increased by menthol. Some studies show that menthol acts as GABAA receptor positive allosteric modulator, Menthol also shares anaesthetic properties similar to propofol, by modulating same sites of GABAA receptor. Menthol is widely used in dental care as an antibacterial agent, effective against several types of streptococci. Mentha arvensis is the species of mint used to make natural menthol crystals. This species is grown in the Uttar Pradesh region in India. -Menthol occurs naturally in peppermint oil, obtained from Mentha x piperita, japanese menthol also contains a small percentage of the 1-epimer, -neomenthol. The biosynthesis of menthol has been investigated in M. x piperita and it begins with the synthesis of the terpene limonene, followed by hydroxylation, and then several reduction and isomerization steps
20.
Chloroform
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Chloroform, or trichloromethane, is an organic compound with formula CHCl3. It is a colorless, sweet-smelling, dense liquid that is produced on a scale as a precursor to PTFE. It is also a precursor to various refrigerants and it is one of the four chloromethanes and a trihalomethane. The molecule adopts tetrahedral molecular geometry with C3v symmetry, the total global flux of chloroform through the environment is approximately 7005660000000000000♠660000 tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil and its half-life in air ranges from 55 to 620 days. Biodegradation in water and soil is slow, chloroform does not significantly bioaccumulate in aquatic organisms. Justus von Liebig carried out the cleavage of chloral. Eugène Soubeiran obtained the compound by the action of chlorine bleach on both ethanol and acetone, in 1834, French chemist Jean-Baptiste Dumas determined chloroforms empirical formula and named it. In 1835, Dumas prepared the substance by the cleavage of trichloroacetic acid. Regnault prepared chloroform by chlorination of chloromethane, in 1842 Dr Robert Mortimer Glover in London discovered the anaesthetic qualities of chloroform on laboratory animals. In 1847, Scottish obstetrician James Y. Simpson was the first to demonstrate the properties of chloroform on humans. By the 1850s, chloroform was being produced on a basis by using the Liebig procedure. Today, chloroform — along with dichloromethane — is prepared exclusively, in industry, chloroform is produced by heating a mixture of chlorine and either chloromethane or methane. CDCl3 is a solvent used in NMR spectroscopy. Deuterochloroform is produced by the reaction, the reaction of acetone with sodium hypochlorite or calcium hypochlorite. The haloform process is now obsolete for the production of ordinary chloroform, deuterochloroform can also be prepared by the reaction of sodium deuteroxide with chloral hydrate, or from ordinary chloroform. The haloform reaction can also occur inadvertently in domestic settings, bleaching with hypochlorite generates halogenated compounds in side reactions, chloroform is the main byproduct. Chlorodifluoromethane is then converted into tetrafluoroethylene, the precursor to Teflon
21.
Potassium hydroxide
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Potassium hydroxide is an inorganic compound with the formula KOH, and is commonly called caustic potash. Along with sodium hydroxide, this solid is a prototypical strong base. It has many industrial and niche applications, most of which exploit its corrosive nature, an estimated 700,000 to 800,000 tonnes were produced in 2005. Approximately 100 times more NaOH than KOH is produced annually, KOH is noteworthy as the precursor to most soft and liquid soaps as well as numerous potassium-containing chemicals. Potassium hydroxide can be found in form by reacting sodium hydroxide with impure potassium. It is usually sold as translucent pellets, which will become tacky in air because KOH is hygroscopic, consequently, KOH typically contains varying amounts of water. Its dissolution in water is strongly exothermic, concentrated aqueous solutions are sometimes called potassium lyes. Even at high temperatures, solid KOH does not dehydrate readily, potassium hydroxide solutions with concentrations of approximately 0.5 to 2. 0% are irritating when coming into contact with the skin, while concentrations higher than 2% are corrosive. At higher temperatures, solid KOH crystallizes in the NaCl crystal structure, the OH group is either rapidly or randomly disordered so that the OH− group is effectively a spherical anion of radius 1.53 Å. At room temperature, the OH− groups are ordered and the environment about the K+ centers is distorted, with K+—OH− distances ranging from 2.69 to 3.15 Å, depending on the orientation of the OH group. KOH forms a series of crystalline hydrates, namely the monohydrate KOH·H 2O, the dihydrate KOH·2 H 2O, approximately 121 g of KOH will dissolve in 100 mL of water at room temperature compared with 100 g of NaOH in the same volume. Lower molecular weight alcohols such as methanol, ethanol, and propanols are also excellent solvents, because of its high affinity for water, KOH serves as a desiccant in the laboratory. It is often used to dry basic solvents, especially amines and pyridines, like NaOH, KOH exhibits high thermal stability. Because of its stability and relatively low melting point, it is often melt-cast as pellets or rods, forms that have low surface area. KOH is highly basic, forming strongly alkaline solutions in water and other polar solvents and these solutions are capable of deprotonating many acids, even weak ones. In analytical chemistry, titrations using solutions of KOH are used to assay acids, KOH, like NaOH, serves as a source of OH−, a highly nucleophilic anion that attacks polar bonds in both inorganic and organic materials. In perhaps its most well-known reaction, aqueous KOH saponifies esters, KOH + RCO2R → RCO2K + ROH When R is a long chain and this reaction is manifested by the greasy feel that KOH gives when touched — fats on the skin are rapidly converted to soap and glycerol. Molten KOH is used to displace halides and other leaving groups, the reaction is especially useful for aromatic reagents to give the corresponding phenols
22.
Sea urchin
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Sea urchins or urchins, archaically called sea hedgehogs, are small, spiny, globular animals that, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. About 950 species of echinoids inhabit all oceans from the intertidal to 5,000 metres deep, the shell, or test, of sea urchins is round and spiny, typically from 3 to 10 cm across. Common colors include black and dull shades of green, olive, brown, purple, blue, Sea urchins move slowly, feeding primarily on algae. Sea otters, starfish, wolf eels, triggerfish, and other predators hunt and their roe is a delicacy in many cuisines. The name urchin is an old word for hedgehog, which sea urchins resemble, Sea urchins are members of the phylum Echinodermata, which also includes sea stars, sea cucumbers, brittle stars, and crinoids. Like other echinoderms, they have five-fold symmetry and move by means of hundreds of tiny, transparent, the symmetry is not obvious in the living animal, but is easily visible in the dried test. The irregular sea urchins are an infra-class inside the Euechinoidea, called Irregularia, irregular echinoids include, flattened sand dollars, sea biscuits, and heart urchins. Together with sea cucumbers, they make up the subphylum Echinozoa, Sea cucumbers and the irregular echinoids have secondarily evolved diverse shapes. Urchins typically range in size from 6 to 12 cm, although the largest species can reach up to 36 cm, like other echinoderms, sea urchin early larvae have bilateral symmetry, but they develop five-fold symmetry as they mature. This is most apparent in the sea urchins, which have roughly spherical bodies with five equally sized parts radiating out from their central axes. Several sea urchins, however, including the sand dollars, are oval in shape, with front and rear ends. In these urchins, the surface of the body is slightly domed. This irregular body form has evolved to allow the animals to burrow through sand or other soft materials, Sea urchins tube feet arise from the five ambulacral grooves. Tube feet are moved by a vascular system, which works through hydraulic pressure, allowing the sea urchin to pump water into and out of the tube feet. The lower half of a sea urchins body is referred to as the surface, because it contains the mouth. The internal organs are enclosed in a shell or test composed of fused plates of calcium carbonate covered by a thin dermis and epidermis. The test is rigid, and divides into five ambulacral grooves separated by five interambulacral areas, each of these areas consists of two rows of plates, so the sea urchin test includes 20 rows of plates in total. The plates are covered in rounded tubercles, to which the spines are attached, the inner surface of the test is lined by peritoneum
23.
Japanese rice fish
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The Japanese rice fish, also known as the medaka and Japanese killifish, is a member of genus Oryzias, the only genus in the subfamily Oryziinae. This small native of East Asia is a denizen of rice paddies, marshes, ponds, slow-moving streams and it is euryhaline, occurring in both brackish and freshwater. Bright yellow, red or green transgenic populations, similar to GloFish, have also been developed, the medaka has been a popular pet since the 17th century in Japan. After fertilization, the female carries her eggs attached between her anal fins for a period before depositing them on plants or alike. This limits the range of definite O. latipes to Japan, eastern and southern Honshu, Shikoku, Kyushu. Formerly included in this species but now regarded as separate are O. sakaizumii in northwestern Honshu in Japan, the taxonomic position of certain populations, including some in China, Laos and east Korea, is unclear and require further study. It is possible that all these Chinese populations are part of O. sinensis, the east Korean population is part of a clade with O. sakaizumii and O. latipes. Based on morphology it is closer to O. sakaizumii than O. latipes, O. latipes has been introduced to Hokkaido in northern Japan. There are other reports of introductions around the world, but at least most of those in mainland Asia, Oryzias latipes is a model organism and is extensively used in many areas of biological research, most notably in toxicology. Medaka have a gestation period, and are reproductively prolific — characteristics that make them easy to rear in the laboratory. They can withstand cold and can be shipped easily and it has relatively small genome as well as a generation time of 7 weeks and hardier growth in a broad temperature range. Transgenic medaka are relatively easy to produce, there are also many mutations that show up in medaka at random, for example, a mutant strain that lacks scales, and one with extra-long fins. Haploid embryonic stem cell lines have been established, O. latipes carries the distinction of having been the first vertebrate to mate in orbit. The result of the mating was a brood of healthy fry, O. latipes returned to space in 2012, launched aboard a Soyuz spacecraft Soyuz TMA-06M and housed in an aquarium aboard the International Space Station. View the oryLat2 genome assembly in the UCSC Genome Browser
24.
GABAA receptor
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The GABAA receptor is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid, the major inhibitory neurotransmitter in the nervous system. Upon activation, the GABAA receptor selectively conducts Cl− through its pore and this causes an inhibitory effect on neurotransmission by diminishing the chance of a successful action potential occurring. The reversal potential of the GABAA-mediated IPSP in normal solution is −70 mV, the active site of the GABAA receptor is the binding site for GABA and several drugs such as muscimol, gaboxadol, and bicuculline. The protein also contains a number of different allosteric binding sites which modulate the activity of the receptor indirectly, GABAA receptors occur in all organisms that have a nervous system. To a limited extent the receptors can be found in non-neuronal tissues, due to their wide distribution within the nervous system of mammals they play a role in virtually all brain functions. The ionotropic GABAA receptor protein complex is also the target of the benzodiazepine class of tranquilizer drugs. In addition peripheral benzodiazepine receptors exist which are not associated with GABAA receptors, in order for GABAA receptors to be sensitive to the action of benzodiazepines they need to contain an α and a γ subunit, between which the benzodiazepine binds. This potentiates the effect of the available GABA leading to sedative. Different benzodiazepines have different affinities for GABAA receptors made up of different collection of subunits, the much sought structure of GABAA receptor was finally resolved, with the disclosure of the crystal structure of human β3 homopentameric GABAA receptor. GABAA receptor is a transmembrane receptor that consists of five subunits arranged around a central pore. Each subunit comprises four transmembrane domains with both the N- and C-terminus located extracellularly, the receptor sits in the membrane of its neuron, usually localized at a synapse, postsynaptically. However, some isoforms may be found extrasynaptically, the net effect is typically inhibitory, reducing the activity of the neuron. The GABAA channel opens quickly and thus contributes to the part of the inhibitory post-synaptic potential. The endogenous ligand that binds to the site is inosine. There are numerous subunit isoforms for the GABAA receptor, which determine the receptors agonist affinity, chance of opening, conductance, five subunits can combine in different ways to form GABAA channels. The minimal requirement to produce a GABA-gated ion channel is the inclusion of both α and β subunits, but the most common type in the brain is a pentamer comprising two αs, two βs, and a γ. The receptor binds two GABA molecules, at the interface between an α and a β subunit, a number of ligands have been found to bind to various sites on the GABAA receptor complex and modulate it besides GABA itself
25.
Alcohol
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In chemistry, an alcohol is any organic compound in which the hydroxyl functional group is bound to a saturated carbon atom. The term alcohol originally referred to the alcohol ethanol, the predominant alcohol in alcoholic beverages. The suffix -ol in non-systematic names also typically indicates that the substance includes a functional group and, so. But many substances, particularly sugars contain hydroxyl functional groups without using the suffix, an important class of alcohols, of which methanol and ethanol are the simplest members is the saturated straight chain alcohols, the general formula for which is CnH2n+1OH. The word alcohol is from the Arabic kohl, a used as an eyeliner. Al- is the Arabic definite article, equivalent to the in English, alcohol was originally used for the very fine powder produced by the sublimation of the natural mineral stibnite to form antimony trisulfide Sb 2S3, hence the essence or spirit of this substance. It was used as an antiseptic, eyeliner, and cosmetic, the meaning of alcohol was extended to distilled substances in general, and then narrowed to ethanol, when spirits as a synonym for hard liquor. Bartholomew Traheron, in his 1543 translation of John of Vigo, Vigo wrote, the barbarous auctours use alcohol, or alcofoll, for moost fine poudre. The 1657 Lexicon Chymicum, by William Johnson glosses the word as antimonium sive stibium, by extension, the word came to refer to any fluid obtained by distillation, including alcohol of wine, the distilled essence of wine. Libavius in Alchymia refers to vini alcohol vel vinum alcalisatum, Johnson glosses alcohol vini as quando omnis superfluitas vini a vino separatur, ita ut accensum ardeat donec totum consumatur, nihilque fæcum aut phlegmatis in fundo remaneat. The words meaning became restricted to spirit of wine in the 18th century and was extended to the class of substances so-called as alcohols in modern chemistry after 1850, the term ethanol was invented 1892, based on combining the word ethane with ol the last part of alcohol. In the IUPAC system, in naming simple alcohols, the name of the alkane chain loses the terminal e and adds ol, e. g. as in methanol and ethanol. When necessary, the position of the group is indicated by a number between the alkane name and the ol, propan-1-ol for CH 3CH 2CH 2OH, propan-2-ol for CH 3CHCH3. If a higher priority group is present, then the prefix hydroxy is used, in other less formal contexts, an alcohol is often called with the name of the corresponding alkyl group followed by the word alcohol, e. g. methyl alcohol, ethyl alcohol. Propyl alcohol may be n-propyl alcohol or isopropyl alcohol, depending on whether the group is bonded to the end or middle carbon on the straight propane chain. As described under systematic naming, if another group on the molecule takes priority, Alcohols are then classified into primary, secondary, and tertiary, based upon the number of carbon atoms connected to the carbon atom that bears the hydroxyl functional group. The primary alcohols have general formulas RCH2OH, the simplest primary alcohol is methanol, for which R=H, and the next is ethanol, for which R=CH3, the methyl group. Secondary alcohols are those of the form RRCHOH, the simplest of which is 2-propanol, for the tertiary alcohols the general form is RRRCOH
26.
Alcohol (drug)
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Ethanol, also called alcohol, ethyl alcohol, and drinking alcohol, is the principal type of alcohol found in alcoholic beverages. It is a volatile, flammable, colorless liquid with a characteristic odor. Its chemical formula is C 2H 6O, which can be written also as CH 3-CH 2-OH or C 2H 5-OH, ethanol is mostly produced by the fermentation of sugars by yeasts, or by petrochemical processes. It is a psychoactive drug, causing a characteristic intoxication. It is widely used as a solvent, as fuel, and as a feedstock for synthesis of other chemicals, the eth- prefix and the qualifier ethyl in ethyl alcohol originally come from the name ethyl assigned in 1834 to the group C 2H 5- by Justus Liebig. He coined the word from the German name Aether of the compound C 2H 5-O-C 2H5, according to the Oxford English Dictionary, Ethyl is a contraction of the Ancient Greek αἰθήρ and the Greek word ύλη. The name ethanol was coined as a result of a resolution that was adopted at the International Conference on Chemical Nomenclature that was held in April 1892 in Geneva, Switzerland. The term alcohol now refers to a class of substances in chemistry nomenclature. The Oxford English Dictionary claims that it is a loan from Arabic al-kuḥl, a powdered ore of antimony used since aniquity as a cosmetic. The use of alcohol for ethanol is modern, first recorded 1753, the systematic use in chemistry dates to 1850. Ethanol is used in medical wipes and most common antibacterial hand sanitizer gels as an antiseptic, ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses. However, ethanol is ineffective against bacterial spores, ethanol may be administered as an antidote to methanol and ethylene glycol poisoning. Ethanol, often in high concentrations, is used to dissolve many water-insoluble medications, as a central nervous system depressant, ethanol is one of the most commonly consumed psychoactive drugs. The amount of ethanol in the body is typically quantified by blood alcohol content, small doses of ethanol, in general, produce euphoria and relaxation, people experiencing these symptoms tend to become talkative and less inhibited, and may exhibit poor judgment. Ethanol is commonly consumed as a drug, especially while socializing. The largest single use of ethanol is as a fuel and fuel additive. Brazil in particular relies heavily upon the use of ethanol as an engine fuel, gasoline sold in Brazil contains at least 25% anhydrous ethanol. Hydrous ethanol can be used as fuel in more than 90% of new gasoline fueled cars sold in the country, Brazilian ethanol is produced from sugar cane and noted for high carbon sequestration
27.
Ethchlorvynol
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Ethchlorvynol/ˌɛθklɔːrˈvaɪnɒl/ is a sedative and hypnotic medication developed by Pfizer in the 1950s. In the United States it was sold by Abbott Laboratories under the tradename Placidyl, Placidyl was available in 200 mg.500 mg. and 750 mg. strength capsules. While the 500 mg. and 750 mg. strength capsules were for use in reducing sleep latency, Abbott discontinued production in 1999, after which Placidyl was available for about a year in the United States. Although, theoretically, ethchlorvynol could be manufactured for sale in the United States by another pharmaceutical company, individuals with a valid prescription for the substance may legally transport a reasonable amount of ethclorvynol with them into the United States. Ethchlorvynol was used to treat insomnia, but prescriptions for the drug had fallen significantly by 1990, as other hypnotics that were considered safer became much more common. It is no longer prescribed in the United States due to unavailability, along with expected sedative effects of relaxation and drowsiness, adverse reactions to ethchlorvynol include skin rash, faintness, restlessness and euphoria. Early adjustment side effects may include nausea and vomiting, numbness, blurred vision, stomach pains, after prolonged use, withdrawal symptoms may include convulsions, hallucinations, and amnesia. As with most hypnotics, Placidyl was indicated for use in the treatment of insomnia for a period of time. However, it was not uncommon for doctors to prescribe Placidyl for extended periods of time. During the late 1970s, ethchlorvynol was sometimes over-prescribed causing an epidemic of persons who quickly became addicted to this powerful drug. Occasional deaths would occur when addicted persons would try to inject the drug directly into a vein or an artery, ethchlorvynol is not compatible with intravenous injection and serious injury or death can occur when it is used in this manner. Ethchlorvynol is a member of the class of sedative-hypnotic carbinols, which includes methylparafynol and it is not a barbituric acid derivative. The systematic name of ethchlorvynol is usually given as ethyl 2-chlorovinyl ethynyl carbinol or 1-chloro-3-ethylpent-1-en-4-yn-3-ol, ethchlorvynol is synthesized by an ethynylation reaction using lithium acetylide and 1-chloro-1-penten-3-one in liquid ammonia, followed by acidic work-up. Electronic Orange Book, Approved Drug Products with Therapeutic Equivalence Evaluations Food and Drug Administration
28.
2,2,2-Trichloroethanol
–
2,2, 2-Trichloroethanol is an organic compound related to ethanol, except the hydrogen atoms at position 2 are replaced with chlorine atoms. In humans, its effects are similar to those of its prodrugs, chloral hydrate. It has, historically, been used as a sedative hypnotic, the hypnotic drug triclofos is metabolized in vivo to 2,2, 2-trichloroethanol. Chronic exposure may result in kidney and liver damage
29.
Barbiturate
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A barbiturate is a drug that acts as a central nervous system depressant, and can therefore produce a wide spectrum of effects, from mild sedation to total anesthesia. They are also effective as anxiolytics, hypnotics, and anticonvulsants and these effects, however, are somewhat weak, and may react with a patients other medications or sedatives. This fact precludes barbiturates from being used in surgery or in the presence of other analgesics, in mice, barbiturates are hyperalgesic, increasing the sensitivity to pain. Barbiturates have addiction potential, both physical and psychological, Barbiturates are derivatives of barbituric acid. However, barbiturates are still used as anticonvulsants, as para-operative sedatives, Barbiturates in high doses are used for physician-assisted suicide, and in combination with a muscle relaxant for euthanasia and for capital punishment by lethal injection. Barbiturates are frequently employed as euthanizing agents in veterinary medicine. Thiopental is a barbiturate that is marketed under the name sodium pentothal. When dissolved in water, sodium amytal can be swallowed, or it can be administered by intravenous injection, the memory-impairing effects and cognitive impairments induced by the drug are thought to reduce a subjects ability to invent and remember lies. There are special risks to consider for older adults, women who are pregnant, when a person ages, the body becomes less able to rid itself of barbiturates. As a result, people over the age of sixty-five are at risk of experiencing the harmful effects of barbiturates, including drug dependence. When barbiturates are taken during pregnancy, the passes through the mothers gastric juice to her fetus. After the baby is born, it may experience withdrawal symptoms and have trouble breathing, in addition, nursing mothers who take barbiturates may transmit the drug to their babies through breast milk. A rare adverse reaction to barbiturates is Stevens-Johnson syndrome, which affects the mucous membranes. With regular use, tolerance to the effects of barbiturates develops, similar to benzodiazepines the longer acting barbiturates produce a less severe withdrawal syndrome than short acting and ultra short acting barbiturates. Withdrawal symptoms are dose-dependent with heavier users being affected worse than lower-dose addicts, mental cravings for barbiturates can last for months or years in some cases and counselling/support groups are highly encouraged by addiction specialists. The lethal dosage of barbiturates varies greatly with tolerance and from one individual to another, tolerance to the anticonvulsant effects tends to correlate more with tolerance to physiological effects, however, meaning that they are still a viable option for long-term epilepsy treatment. Barbiturates in overdose with other CNS depressants are even more due to additive CNS. The longest-acting barbiturates have half-lives of a day or more, Barbiturates induce a number of hepatic CYP enzymes, leading to exaggerated effects from many prodrugs and decreased effects from drugs which are metabolized by these enzymes to inactive metabolites
30.
Amobarbital
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Amobarbital is a drug that is a barbiturate derivative. It is a crystalline powder with no odor and a slightly bitter taste. It was first synthesized in Germany in 1923, if amobarbital is taken for extended periods of time, physical and psychological dependence can develop. Amobarbital withdrawal mimics delirium tremens and may be life-threatening, Amobarbital has been used in a study to inhibit mitochondrial electron transport in the rat heart. A1988 study found that amobarbital increases benzodiazepine receptor binding in vivo with less potency than secobarbital and pentobarbital and it has an LD50 in mice of 212 mg/kg s. c. Amobarbital undergoes both hydroxylation to form 3-hydroxyamobarbital, and N-glucosidation to form 1-amobarbital, anxiety Epilepsy Insomnia Wada test When given slowly by an intravenous route, sodium amobarbital has a reputation for acting as a so-called truth serum. Under the influence, a person will divulge information that under normal circumstances they would block, as such, the drug was first employed clinically by Dr. William Bleckwenn at the University of Wisconsin to circumvent inhibitions in psychiatric patients. The use of amobarbital as a truth serum has lost credibility due to the discovery that a subject can be coerced into having a memory of the event. The drug may be used intravenously to interview patients with catatonic mutism and it was used by the United States armed forces during World War II in an attempt to treat shell shock and return soldiers to the front-line duties. This use has since been discontinued as the powerful sedation, cognitive impairment, being chemically related to phenobarbital, it might also do the same thing to digitoxin, a cardiac glycoside. Amobarbital, like all barbiturates, is synthesized by reacting malonic acid derivatives with urea derivatives, in particular, in order to make amobarbital, α-ethyl-α-isoamylmalonic ester is reacted with urea. It has been used to convict alleged murderers such as Andres English-Howard and he was surreptitiously administered the drug by his lawyer, and under the influence of it he revealed why he strangled her and under what circumstances. A year later he confessed on the stand and was convicted on the basis of these statements. He later committed suicide in his cell, on the night of August 28,1951, Robert Walkers housekeeper found the actor in an emotional state. She called Walkers psychiatrist who arrived and administered amobarbital for sedation, walker was allegedly drinking prior to his emotional outburst, and it is believed the combination of amobarbital and alcohol resulted in a severe reaction. As a result, he passed out and stopped breathing, walker died at 32 years old. Street names for Amobarbital include blues, blue angles, blue birds, and blue devils
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