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.
Density
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The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume, ρ = m V, where ρ is the density, m is the mass, and V is the volume. In some cases, density is defined as its weight per unit volume. For a pure substance the density has the numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity, osmium and iridium are the densest known elements at standard conditions for temperature and pressure but certain chemical compounds may be denser. Thus a relative density less than one means that the floats in water. The density of a material varies with temperature and pressure and this variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object, increasing the temperature of a substance decreases its density by increasing its volume. In most materials, heating the bottom of a results in convection of the heat from the bottom to the top. This causes it to rise relative to more dense unheated material, the reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is a property in that increasing the amount of a substance does not increase its density. Archimedes knew that the irregularly shaped wreath could be crushed into a cube whose volume could be calculated easily and compared with the mass, upon this discovery, he leapt from his bath and ran naked through the streets shouting, Eureka. As a result, the term eureka entered common parlance and is used today to indicate a moment of enlightenment, the story first appeared in written form in Vitruvius books of architecture, two centuries after it supposedly took place. Some scholars have doubted the accuracy of this tale, saying among other things that the method would have required precise measurements that would have been difficult to make at the time, from the equation for density, mass density has units of mass divided by volume. As there are units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per metre and the cgs unit of gram per cubic centimetre are probably the most commonly used units for density.1,000 kg/m3 equals 1 g/cm3. In industry, other larger or smaller units of mass and or volume are often more practical, see below for a list of some of the most common units of density
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.
Acid dissociation constant
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An acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the constant for a chemical reaction known as dissociation in the context of acid–base reactions. In the example shown in the figure, HA represents acetic acid, and A− represents the acetate ion, the chemical species HA, A− and H3O+ are said to be in equilibrium when their concentrations do not change with the passing of time. The definition can then be more simply H A ⇌ A − + H +, K a = This is the definition in common usage. A weak acid has a pKa value in the approximate range −2 to 12 in water, pKa values for strong acids can, however, be estimated by theoretical means. The definition can be extended to non-aqueous solvents, such as acetonitrile and dimethylsulfoxide. Denoting a solvent molecule by S H A + S ⇌ A − + S H +, K a = When the concentration of solvent molecules can be taken to be constant, K a =, as before. The value of pKa also depends on structure of the acid in many ways. For example, Pauling proposed two rules, one for successive pKa of polyprotic acids, and one to estimate the pKa of oxyacids based on the number of =O and −OH groups. Other structural factors that influence the magnitude of the dissociation constant include inductive effects, mesomeric effects. Hammett type equations have frequently applied to the estimation of pKa. The quantitative behaviour of acids and bases in solution can be only if their pKa values are known. These calculations find application in different areas of chemistry, biology, medicine. Acid dissociation constants are essential in aquatic chemistry and chemical oceanography. In living organisms, acid–base homeostasis and enzyme kinetics are dependent on the pKa values of the acids and bases present in the cell. According to Arrheniuss original definition, an acid is a substance that dissociates in solution, releasing the hydrogen ion H+. The equilibrium constant for this reaction is known as a dissociation constant. Brønsted and Lowry generalised this further to an exchange reaction
14.
Safety data sheet
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A safety data sheet, material safety data sheet, or product safety data sheet is an important component of product stewardship, occupational safety and health, and spill-handling procedures. SDS formats can vary from source to source within a country depending on national requirements, SDSs are a widely used system for cataloging information on chemicals, chemical compounds, and chemical mixtures. SDS information may include instructions for the use and potential hazards associated with a particular material or product. The SDS should be available for reference in the area where the chemicals are being stored or in use, there is also a duty to properly label substances on the basis of physico-chemical, health and/or environmental risk. Labels can include hazard symbols such as the European Union standard symbols, a SDS for a substance is not primarily intended for use by the general consumer, focusing instead on the hazards of working with the material in an occupational setting. It is important to use an SDS specific to country and supplier, as the same product can have different formulations in different countries. The formulation and hazard of a product using a name may vary between manufacturers in the same country. Safety data sheets have made an integral part of the system of Regulation No 1907/2006. The SDS must be supplied in a language of the Member State where the substance or mixture is placed on the market. The 16 sections are, SECTION1, Identification of the substance/mixture, relevant identified uses of the substance or mixture and uses advised against 1.3. Details of the supplier of the safety data sheet 1.4, Emergency telephone number SECTION2, Hazards identification 2.1. Classification of the substance or mixture 2.2, Other hazards SECTION3, Composition/information on ingredients 3.1. Mixtures SECTION4, First aid measures 4.1, Description of first aid measures 4.2. Most important symptoms and effects, both acute and delayed 4.3, indication of any immediate medical attention and special treatment needed SECTION5, Firefighting measures 5.1. Special hazards arising from the substance or mixture 5.3, advice for firefighters SECTION6, Accidental release measure 6.1. Personal precautions, protective equipment and emergency procedures 6.2, methods and material for containment and cleaning up 6.4. Reference to other sections SECTION7, Handling and storage 7.1, conditions for safe storage, including any incompatibilities 7.3. Specific end use SECTION8, Exposure controls/personal protection 8.1, Exposure controls SECTION9, Physical and chemical properties 9.1
15.
Anthraquinone
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Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula C 14H 8O2. Several isomers are possible, each of which can be viewed as a quinone derivative, the term anthraquinone, however, almost invariably refers to one specific isomer,9, 10-anthraquinone wherein the keto groups are located on the central ring. It is a block of many dyes and is used in bleaching pulp for papermaking. It is a highly crystalline solid, poorly soluble in water. For instance, it is almost completely insoluble in ethanol near room temperature but 2.25 g will dissolve in 100 g of boiling ethanol,9, 10-Anthraquinone is obtained industrially by the oxidation of anthracene, a reaction that is localized at the central ring. It is also prepared by the Friedel-Crafts reaction of benzene and phthalic anhydride in presence of AlCl3, the resulting o-benzoylbenzoic acid then undergoes cyclization, forming anthraquinone. This reaction is useful for producing substituted anthraquinones, the Diels-Alder reaction of naphthoquinone and butadiene followed by oxidative dehydrogenation will also produce 9, 10-anthraquinone. Lastly, BASF has developed a process proceeds via the acid-catalyzed dimerization of styrene to give a 1, 3-diphenylbutene. It also arises via the Rickert-Alder reaction, a retro-Diels-Alder reaction, in a classic organic reaction called the Bally–Scholl synthesis, named after Oscar Bally and Roland Scholl, anthraquinone condenses with glycerol forming benzanthrone. In this reaction, the quinone is first reduced with copper metal in sulfuric acid after which the glycerol is added, synthetic dyes are often derived from 9, 10-anthraquinone, such as alizarin. Important derivatives are 1-nitroanthraquinone, anthraquinone-1-sulfonic acid, and the dinitroanthraquinone, natural pigments that are derivatives of anthraquinone are found, inter alia, in aloe latex, senna, rhubarb, and cascara buckthorn, fungi, lichens, and some insects. 9, 10-Anthraquinone is used as an additive in production of paper pulp by alkaline processes, like the Kraft. The anthraquinone is a redox catalyst, the reaction mechanism may involve single electron transfer. The anthraquinone is oxidizing the reducing end of polysaccharides in the pulp, i. e. cellulose and hemicellulose, the anthraquinone is reduced to 9, 10-dihydroxyanthracene which then can react with lignin. The lignin is degraded and becomes more water-soluble and thereby more easy to wash away from the pulp and this process gives an increase in yield of pulp, typically 1-3% and a reduction in kappa number. Sodium 2-anthraquinonesulfonate is an anthraquinone derivative that was the first anthraquinone derivative discovered to have a catalytic effect in the alkaline pulping processes. A large industrial application of anthraquinones is for the production of hydrogen peroxide, 2-Ethyl-9, 10-anthraquinone or a related alkyl derivatives is used, rather than anthraquinone itself. 9, 10-Anthraquinone is used as a bird repellant on seeds and it has also been mixed with lanolin and used as a wool spray to protect sheep flocks against kea attacks in New Zealand
16.
Anthracene
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Anthracene is a solid polycyclic aromatic hydrocarbon of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar, Anthracene is used in the production of the red dye alizarin and other dyes. Anthracene is colorless but exhibits a blue fluorescence under ultraviolet radiation, coal tar, which contains around 1. 5% anthracene, remains a major source of this material. Common impurities are phenanthrene and carbazole, a classic laboratory method for the preparation of anthracene is by cyclodehydration of o-methyl- or o-methylene-substituted diarylketones in the so-called Elbs reaction. It may also occur in the interstellar medium, more than 20% of the carbon in the universe may be associated with PAHs, including anthracene. Anthracene photodimerizes by the action of UV light, The dimer, called dianthracene, is connected by a pair of new carbon-carbon bonds and it reverts to anthracene thermally or with UV irradiation below 300 nm. The reaction is affected by the presence of oxygen, reduction of anthracene with alkali metals yields the deeply colored radical anion salts M+−. Hydrogenation gives 9, 10-dihydroanthracene, preserving the aromaticity of the two flanking rings. Chemical oxidation occurs readily, giving anthraquinone, C14H8O2, for example using hydrogen peroxide, Anthracene also reacts with dienophile singlet oxygen in a -cycloaddition, Anthracene is converted mainly to anthraquinone, a precursor to dyes. Anthracene, a wide band-gap organic semiconductor is used as a scintillator for detectors of high energy photons, electrons, plastics, such as polyvinyltoluene, can be doped with anthracene to produce a plastic scintillator that is approximately water-equivalent for use in radiation therapy dosimetry. Anthracenes emission spectrum peaks at between 400 nm and 440 nm and it is also used in wood preservatives, insecticides, and coating materials. Anthracene is one of the three components which are used to produce the smoke released during a Papal Conclave. A variety of anthracene derivatives find specialized uses, derivatives having a hydroxyl group are 1-hydroxyanthracene and 2-hydroxyanthracene, homologous to phenol and naphthols, and hydroxyanthracene are pharmacologically active. Anthracene may also be found with multiple groups, as in 9. Many investigations indicate that anthracene is noncarcinogenic, consistently negative findings in numerous in vitro, early experiments suggested otherwise because crude samples were contaminated with other polycyclic aromatic compounds. Furthermore, it is readily biodegraded in soil and it is especially susceptible to degradation in the presence of light. 9, 10-Dithioanthracene, walks in a straight line
17.
Organic compound
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An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
18.
Dye
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A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber. Both dyes and pigments are colored because they absorb some wavelengths of light more than others, in contrast to dyes, pigments are insoluble and have no affinity for the substrate. Some dyes can be precipitated with a salt to produce a lake pigment. The majority of natural dyes are from plant sources, roots, berries, bark, leaves, and wood, fungi, textile dyeing dates back to the Neolithic period. Throughout history, people have dyed their textiles using common, locally available materials, scarce dyestuffs that produced brilliant and permanent colors such as the natural invertebrate dyes Tyrian purple and crimson kermes were highly prized luxury items in the ancient and medieval world. Plant-based dyes such as woad, indigo, saffron, and madder were raised commercially and were important trade goods in the economies of Asia, across Asia and Africa, patterned fabrics were produced using resist dyeing techniques to control the absorption of color in piece-dyed cloth. Dyes from the New World such as cochineal and logwood were brought to Europe by the Spanish treasure fleets, dyed flax fibers have been found in the Republic of Georgia in a prehistoric cave dated to 36,000 BP. Archaeological evidence shows that, particularly in India and Phoenicia, dyeing has been carried out for over 5,000 years. The dyes were obtained from animal, vegetable or mineral origin, by far the greatest source of dyes has been from the plant kingdom, notably roots, berries, bark, leaves and wood, but only a few have ever been used on a commercial scale. The discovery of synthetic dyes late in the 19th century ended the large-scale market for natural dyes. These dyes are made from synthetic resources such as petroleum by-products, the first human-made organic aniline dye, mauveine, was discovered serendipitously by William Henry Perkin in 1856, the result of a failed attempt at the total synthesis of quinine. Other aniline dyes followed, such as fuchsine, safranine, many thousands of synthetic dyes have since been prepared. These may be natural or synthetic, other than pigmentation, they have a range of applications including organic dye lasers, optical media and camera sensors. This is the basic classification Dyes are classified according to their solubility, acid dyes are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dye baths. Attachment to the fiber is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fiber, acid dyes are not substantive to cellulosic fibers. Most synthetic food colors fall in this category, basic dyes are water-soluble cationic dyes that are mainly applied to acrylic fibers, but find some use for wool and silk. Usually acetic acid is added to the dye bath to help the uptake of the dye onto the fiber, basic dyes are also used in the coloration of paper
19.
Rubia
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Rubia is a genus of flowering plants in the Rubiaceae family. It contains around 80 species of perennial scrambling or climbing herbs and subshrubs native to the Old World, the genus and its best-known species are commonly known as madder, e. g. Rubia tinctorum, Rubia peregrina, and Rubia cordifolia. Rubia was an important source of a red pigment in many regions of Asia, Europe. The genus name Rubia derives from the Latin ruber meaning red, the plants roots contain an anthracene compound called alizarin that gives its red colour to a textile dye known as Rose madder. It was also used as a colourant, especially for paint, the synthesis of alizarin greatly reduced demand for the natural compound. Cloth dyed with it has found on Egyptian mummies. It was the used for dyeing the cloaks of the Libyan women in the days of Herodotus. It is the erythrodanon of Pedanius Dioscorides, who wrote of its cultivation in Caria, and of Hippocrates, and the Rubia of Pliny. R. tinctorum was extensively cultivated in south Europe, France, where it is called garance, and the Netherlands, large quantities were imported into England from Smyrna, Trieste, Livorno, etc. The cultivation, however, decreased after alizarin was made artificially, Madder was employed medicinally in ancient civilizations and in the middle ages. Its most remarkable physiological effect was found to be that of colouring red the bones of animals fed upon it, as also the claws and this appears to be due to the chemical affinity of calcium phosphate for the colouring matter. This property was used to enable physiologists to ascertain the manner in which bones develop, Rubia in the World Checklist of Rubiaceae
20.
Rose madder
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Rose madder is the commercial name sometimes used to designate a paint made from the pigment madder lake, a traditional lake pigment extracted from the common madder plant Rubia tinctorum. Madder lake contains two red dyes, alizarin and purpurin. Madder has been cultivated as a dyestuff since antiquity in Central Asia, South Asia, and Egypt, where it was grown as early as 1500 BC. Cloth dyed with madder root dye was found in the tomb of the Pharaoh Tutankhamun and on an Egyptian tomb painting from the Graeco-Roman period and it was also found in ancient Greece, and in Italy in the Baths of Titus and the ruins of Pompeii. In Spain, madder was introduced and then cultivated by the Moors, the production of a lake pigment from madder seems to have been first invented by the ancient Egyptians. Ideal color was said to come from plants 18 to 28 months old that had grown in calcareous soil. The resulting madder lake had a less fugitive color and could be used more efficaciously, for example by blending it into a paint. Over the following years, other salts, including those containing chromium, iron. In 1827, the French chemists Pierre-Jean Robiquet and Colin began producing garancine and they then found that madder lake contained two colorants, the red alizarin and the more rapidly fading purpurin. Purpurin is only present in the form of madder and gives a distinctive orange/red generally warmer tone that pure synthetic alizarin does not. Purpurin fluoresces yellow to red under ultraviolet light, while synthetic alizarin slightly shows violet, alizarin was discovered before purpurin, by heating the ground madder with acid and potash. A yellow vapor crystallized into bright red needles, alizarin and this alizarin concentrate comprises only 1% of the madder root. Natural rose madder supplied half the world with red, until 1868, however, their recipe was not feasible for large-scale production, it required expensive and volatile substances, specifically bromine. William Perkin, the inventor of mauve, filed a patent in June 1869 for a new way to produce alizarin without bromine. Gräbe, Liebermann, and Heinrich Caro filed a patent for a similar process just one day before Perkin did - yet both patents were granted, as Perkins had been sealed first. They divided the market in half, Perkin sold to the English market, because this synthetic alizarin dye could be produced for a fraction of the cost of the natural madder dye, it quickly replaced all madder-based colorants then in use. In turn, alizarin itself has now largely replaced by the more light-resistant quinacridone pigments originally developed at DuPont in 1958. It is still manufactured in traditional ways to meet the demands of the art market
21.
Staining
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Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. Stains and dyes are used in biology and medicine to highlight structures in biological tissues for viewing. Stains may be used to define and examine bulk tissues, cell populations, in biochemistry it involves adding a class-specific dye to a substrate to qualify or quantify the presence of a specific compound. Staining and fluorescent tagging can serve similar purposes, biological staining is also used to mark cells in flow cytometry, and to flag proteins or nucleic acids in gel electrophoresis. Simple staining is staining with only one stain/dye, there are various kinds of multiple staining, many of which are examples of counterstaining, differential staining, or both, including double staining and triple staining. In vivo staining is the process of dyeing living tissues—in vivo means in life, by causing certain cells or structures to take on contrasting colour, their form or position within a cell or tissue can be readily seen and studied. In vitro staining involves colouring cells or structures that have removed from their biological context. Certain stains are often combined to reveal more details and features than a single stain alone, combined with specific protocols for fixation and sample preparation, scientists and physicians can use these standard techniques as consistent, repeatable diagnostic tools. A counterstain is stain that makes cells or structures more visible, for example, crystal violet stains only Gram-positive bacteria in Gram staining. A safranin counterstain is applied that stains all cells, allowing identification of Gram-negative bacteria, while ex vivo, many cells continue to live and metabolize until they are fixed. Some staining methods are based on this property and those stains excluded by the living cells but taken up by the already dead cells are called vital stains. Those that enter and stain living cells are called supravital stains, however, these stains are eventually toxic to the organism, some more so than others. To achieve desired effects, the stains are used in very dilute solutions ranging from 1,5000 to 1,500000, note that many stains may be used in both living and fixed cells. The preparatory steps involved depend on the type of analysis planned, fixation–which may itself consist of several steps–aims to preserve the shape of the cells or tissue involved as much as possible. Sometimes heat fixation is used to kill, adhere, and alter the specimen so it accepts stains, most chemical fixatives generate chemical bonds between proteins and other substances within the sample, increasing their rigidity. Common fixatives include formaldehyde, ethanol, methanol, and/or picric acid, pieces of tissue may be embedded in paraffin wax to increase their mechanical strength and stability and to make them easier to cut into thin slices. Permeabilization involves treatment of cells with a mild surfactant and this treatment dissolves cell membranes, and allows larger dye molecules into the cells interior. Mounting usually involves attaching the samples to a microscope slide for observation
22.
Calcium
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Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft grayish-yellow alkaline earth metal, fifth-most-abundant element by mass in the Earths crust, the ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate. Free calcium metal is too reactive to occur in nature, Calcium is produced in supernova nucleosynthesis. Calcium is a trace element in living organisms. It is the most abundant metal by mass in animals, and it is an important constituent of bone, teeth. In cell biology, the movement of the calcium ion into, Calcium carbonate and calcium citrate are often taken as dietary supplements. Calcium is on the World Health Organizations List of Essential Medicines, Calcium has a wide variety of applications, almost all of which are associated with calcium compounds and salts. Calcium metal is used as a deoxidizer, desulfurizer, and decarbonizer for production of ferrous and nonferrous alloys. In steelmaking and production of iron, Ca reacts with oxygen, Calcium carbonate is used in manufacturing cement and mortar, lime, limestone and aids in production in the glass industry. It also has chemical and optical uses as mineral specimens in toothpastes, Calcium hydroxide solution is used to detect the presence of carbon dioxide in a gas sample bubbled through a solution. The solution turns cloudy where CO2 is present, Calcium arsenate is used in insecticides. Calcium carbide is used to make acetylene gas and various plastics, Calcium chloride is used in ice removal and dust control on dirt roads, as a conditioner for concrete, as an additive in canned tomatoes, and to provide body for automobile tires. Calcium citrate is used as a food preservative, Calcium cyclamate is used as a sweetening agent in several countries. In the United States, it has been outlawed as a suspected carcinogen, Calcium gluconate is used as a food additive and in vitamin pills. Calcium hypochlorite is used as a swimming pool disinfectant, as an agent, as an ingredient in deodorant. Calcium permanganate is used in rocket propellant, textile production, as a water sterilizing agent. Calcium phosphate is used as a supplement for animal feed, fertilizer, in production for dough and yeast products, in the manufacture of glass. Calcium phosphide is used in fireworks, rodenticide, torpedoes, Calcium sulfate is used as common blackboard chalk, as well as, in its hemihydrate form, Plaster of Paris
23.
Natural dye
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Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals. The majority of natural dyes are vegetable dyes from plant sources—roots, berries, bark, leaves, archaeologists have found evidence of textile dyeing dating back to the Neolithic period. In China, dyeing with plants, barks and insects has been traced more than 5,000 years. The essential process of dyeing changed little over time, typically, the dye material is put in a pot of water and then the textiles to be dyed are added to the pot, which is heated and stirred until the color is transferred. Textile fibre may be dyed before spinning, but most textiles are yarn-dyed or piece-dyed after weaving, many mordants, and some dyes themselves, produce strong odors, and large-scale dyeworks were often isolated in their own districts. Plant-based dyes such as woad, indigo, saffron, and madder were raised commercially and were important trade goods in the economies of Asia, across Asia and Africa, patterned fabrics were produced using resist dyeing techniques to control the absorption of color in piece-dyed cloth. Dyes such as cochineal and logwood were brought to Europe by the Spanish treasure fleets, the discovery of man-made synthetic dyes in the mid-19th century triggered a long decline in the large-scale market for natural dyes. Natural dyeing techniques are preserved by artisans in traditional cultures around the world. In the early 21st century, the market for natural dyes in the industry is experiencing a resurgence. Western consumers have become concerned about the health and environmental impact of synthetic dyes in manufacturing. The European Union, for example, has encouraged Indonesian batik cloth producers to switch to natural dyes to improve their market in Europe. Protein fibres require vat, acid, or indirect/mordant dyes, that require a bonding agent, each synthetic fibre requires its own dyeing method, for example, nylon requires acid, disperse and pigment dyes, rayon acetate requires disperse dyes, and so on. The earliest surviving evidence of textile dyeing was found at the large Neolithic settlement at Çatalhöyük in southern Anatolia, polychrome or multicolored fabrics seem to have been developed in the 3rd or 2nd millennium BCE. Textiles with a warp and an ochre-yellow weft were discovered in Egyptian pyramids of the Sixth Dynasty. His contributions to refining the process and his theories on colour brought much praise by the well known poet. Some dyestuffs, such as indigo and lichens, will give good color when used alone, the majority of plant dyes, however, also require the use of a mordant, a chemical used to fix the color in the textile fibres. These dyes are called adjective dyes, by using different mordants, dyers can often obtain a variety of colors and shades from the same dye. Fibres or cloth may be pretreated with mordants, or the mordant may be incorporated in the dyebath, salt helps to fix or increase fastness of colors, vinegar improves reds and purples, and the ammonia in stale urine assists in the fermentation of indigo dyes
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Asia
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Asia covers an area of 44,579,000 square kilometres, about 30% of Earths total land area and 8. 7% of the Earths total surface area. The continent, which has long been home to the majority of the population, was the site of many of the first civilizations. Asia is notable for not only its large size and population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, the western boundary with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. The most commonly accepted boundaries place Asia to the east of the Suez Canal, the Ural River, and the Ural Mountains, and south of the Caucasus Mountains, China and India alternated in being the largest economies in the world from 1 to 1800 A. D. The accidental discovery of America by Columbus in search for India demonstrates this deep fascination, the Silk Road became the main East-West trading route in the Asian hitherland while the Straits of Malacca stood as a major sea route. Asia has exhibited economic dynamism as well as robust population growth during the 20th century, given its size and diversity, the concept of Asia—a name dating back to classical antiquity—may actually have more to do with human geography than physical geography. Asia varies greatly across and within its regions with regard to ethnic groups, cultures, environments, economics, historical ties, the boundary between Asia and Africa is the Red Sea, the Gulf of Suez, and the Suez Canal. This makes Egypt a transcontinental country, with the Sinai peninsula in Asia, the border between Asia and Europe was historically defined by European academics. In Sweden, five years after Peters death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Urals as the border of Asia, the Russians were enthusiastic about the concept, which allowed them to keep their European identity in geography. Tatishchev announced that he had proposed the idea to von Strahlenberg, the latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th century, the border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is usually placed along the crest of the Caucasus Mountains, the border between Asia and the loosely defined region of Oceania is usually placed somewhere in the Malay Archipelago. The terms Southeast Asia and Oceania, devised in the 19th century, have had several different geographic meanings since their inception. The chief factor in determining which islands of the Malay Archipelago are Asian has been the location of the possessions of the various empires there. Lewis and Wigen assert, The narrowing of Southeast Asia to its present boundaries was thus a gradual process, Asia is larger and more culturally diverse than Europe. It does not exactly correspond to the borders of its various types of constituents. From the time of Herodotus a minority of geographers have rejected the three-continent system on the grounds there is no or is no substantial physical separation between them
25.
Egypt
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Egypt, officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba to the east, the Red Sea to the east and south, Sudan to the south, and Libya to the west. Across the Gulf of Aqaba lies Jordan, and across from the Sinai Peninsula lies Saudi Arabia, although Jordan and it is the worlds only contiguous Afrasian nation. Egypt has among the longest histories of any country, emerging as one of the worlds first nation states in the tenth millennium BC. Considered a cradle of civilisation, Ancient Egypt experienced some of the earliest developments of writing, agriculture, urbanisation, organised religion and central government. One of the earliest centres of Christianity, Egypt was Islamised in the century and remains a predominantly Muslim country. With over 92 million inhabitants, Egypt is the most populous country in North Africa and the Arab world, the third-most populous in Africa, and the fifteenth-most populous in the world. The great majority of its people live near the banks of the Nile River, an area of about 40,000 square kilometres, the large regions of the Sahara desert, which constitute most of Egypts territory, are sparsely inhabited. About half of Egypts residents live in areas, with most spread across the densely populated centres of greater Cairo, Alexandria. Modern Egypt is considered to be a regional and middle power, with significant cultural, political, and military influence in North Africa, the Middle East and the Muslim world. Egypts economy is one of the largest and most diversified in the Middle East, Egypt is a member of the United Nations, Non-Aligned Movement, Arab League, African Union, and Organisation of Islamic Cooperation. Miṣr is the Classical Quranic Arabic and modern name of Egypt. The name is of Semitic origin, directly cognate with other Semitic words for Egypt such as the Hebrew מִצְרַיִם, the oldest attestation of this name for Egypt is the Akkadian
26.
Pharaoh
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The word pharaoh ultimately derive from the Egyptian compound pr-ˤ3 great house, written with the two biliteral hieroglyphs pr house and ˤ3 column, here meaning great or high. It was used only in larger phrases such as smr pr-ˤ3 Courtier of the High House, with specific reference to the buildings of the court or palace. From the twelfth dynasty onward, the word appears in a wish formula Great House, may it live, prosper, and be in health, but again only with reference to the royal palace and not the person. During the reign of Thutmose III in the New Kingdom, after the rule of the Hyksos during the Second Intermediate Period. During the eighteenth dynasty the title pharaoh was employed as a designation of the ruler. From the nineteenth dynasty onward pr-ˤ3 on its own was used as regularly as hm. f, the term, therefore, evolved from a word specifically referring to a building to a respectful designation for the ruler, particularly by the twenty-second dynasty and twenty-third dynasty. For instance, the first dated appearance of the pharaoh being attached to a rulers name occurs in Year 17 of Siamun on a fragment from the Karnak Priestly Annals. Here, an induction of an individual to the Amun priesthood is dated specifically to the reign of Pharaoh Siamun and this new practice was continued under his successor Psusennes II and the twenty-second dynasty kings. Shoshenq I was the successor of Siamun. Meanwhile, the old custom of referring to the sovereign simply as pr-ˤ3 continued in traditional Egyptian narratives, by this time, the Late Egyptian word is reconstructed to have been pronounced *par-ʕoʔ whence Herodotus derived the name of one of the Egyptian kings, Φερων. In the Bible, the title also occurs as פרעה, from that, Septuagint φαραώ pharaō and then Late Latin pharaō, both -n stem nouns. The Quran likewise spells it فرعون firawn with n, interestingly, the Arabic combines the original pharyngeal ayin sound from Egyptian, along with the -n ending from Greek. English at first spelt it Pharao, but the King James Bible revived Pharaoh with h from the Hebrew, meanwhile in Egypt itself, *par-ʕoʔ evolved into Sahidic Coptic ⲡⲣ̅ⲣⲟ prro and then rro. Scepters and staves were a sign of authority in ancient Egypt. One of the earliest royal scepters was discovered in the tomb of Khasekhemwy in Abydos, kings were also known to carry a staff, and Pharaoh Anedjib is shown on stone vessels carrying a so-called mks-staff. The scepter with the longest history seems to be the heqa-scepter, the earliest examples of this piece of regalia dates to pre-dynastic times. A scepter was found in a tomb at Abydos that dates to the late Naqada period, another scepter associated with the king is the was-scepter. This is a long staff mounted with an animal head, the earliest known depictions of the was-scepter date to the first dynasty
27.
Tutankhamun
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Tutankhamun was an Egyptian pharaoh of the 18th dynasty, during the period of Egyptian history known as the New Kingdom or sometimes the New Empire Period. He has, since his discovery, been referred to as King Tut. His original name, Tutankhaten, means Living Image of Aten, in hieroglyphs, the name Tutankhamun was typically written Amen-tut-ankh, because of a scribal custom that placed a divine name at the beginning of a phrase to show appropriate reverence. The 1922 discovery by Howard Carter and Lord Carnarvon of Tutankhamuns nearly intact tomb received worldwide press coverage and it sparked a renewed public interest in ancient Egypt, for which Tutankhamuns mask, now in the Egyptian Museum, remains the popular symbol. Exhibits of artifacts from his tomb have toured the world, in February 2010, the results of DNA tests confirmed that he was the son of Akhenaten. His mother was Akhenatens sister and wife, whose name is unknown, the mysterious deaths of a few of those who excavated Tutankhamuns tomb has been popularly attributed to the curse of the pharaohs. Tutankhamun was the son of Akhenaten and one of Akhenatens sisters, as a prince, he was known as Tutankhaten. He ascended to the throne in 1333 BC, at the age of nine or ten and his wet nurse was a woman called Maia, known from her tomb at Saqqara. His teacher was most likely Sennedjem, when he became king, he married his half-sister, Ankhesenpaaten, who later changed her name to Ankhesenamun. They had two daughters, both stillborn, computed tomography studies released in 2011 revealed that one daughter died at 5–6 months of pregnancy and the other at 9 months of pregnancy. No evidence was found in either mummy of congenital anomalies or an apparent cause of death, given his age, the king probably had very powerful advisers, presumably including General Horemheb and Grand Vizier Ay. Horemheb records that the king appointed him lord of the land as hereditary prince to maintain law and he also noted his ability to calm the young king when his temper flared. In his third year, under the influence of his advisors. He ended the worship of the god Aten and restored the god Amun to supremacy, the ban on the cult of Amun was lifted and traditional privileges were restored to its priesthood. The capital was moved back to Thebes and the city of Akhetaten abandoned and this is when he changed his name to Tutankhamun, Living image of Amun, reinforcing the restoration of Amun. As part of his restoration, the king initiated building projects, in particular at Karnak in Thebes, many monuments were erected, and an inscription on his tomb door declares the king had spent his life in fashioning the images of the gods. The traditional festivals were now celebrated again, including those related to the Apis Bull, Horemakhet and his restoration stela says, The temples of the gods and goddesses. Their shrines were deserted and overgrown and their sanctuaries were as non-existent and their courts were used as roads
28.
Pompeii
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Pompeii was an ancient Roman town-city near modern Naples, in the Campania region of Italy, in the territory of the comune of Pompei. Pompeii, along with Herculaneum and many villas in the area, was mostly destroyed and buried under 4 to 6 m of volcanic ash. Researchers believe that the town was founded in the seventh or sixth century BC by the Osci or Oscans. It came under the domination of Rome in the 4th century BC, by the time of its destruction,160 years later, its population was estimated at 11,000 people, and the city had a complex water system, an amphitheatre, gymnasium, and a port. The eruption destroyed the city, killing its inhabitants and burying it under tons of ash, the site was lost for about 1,500 years until its initial rediscovery in 1599 and broader rediscovery almost 150 years later by Spanish engineer Rocque Joaquin de Alcubierre in 1748. The objects that lay beneath the city have been preserved for centuries because of the lack of air and these artefacts provide an extraordinarily detailed insight into the life of a city during the Pax Romana. During the excavation, plaster was used to fill in the voids in the ash layers that once held human bodies and this allowed archaeologists to see the exact position the person was in when he or she died. Pompeii has been a tourist destination for over 250 years, today it has UNESCO World Heritage Site status and is one of the most popular tourist attractions in Italy, with approximately 2.5 million visitors every year. Pompeii in Latin is a second declension plural, the ruins of Pompeii are located near the modern suburban town of Pompei. It stands on a formed by a lava flow to the north of the mouth of the Sarno River. Today it is some distance inland, but in ancient times was nearer to the coast, Pompeii is about 8 km away from Mount Vesuvius. It covered a total of 64 to 67 hectares and was home to approximately 11,000 to 11,500 people on the basis of household counts and it was a major city in the region of Campania. Three sheets of sediment have been found on top of the lava that lies below the city and, mixed in with the sediment, archaeologists have found bits of bone, pottery shards. Carbon dating has placed the oldest of these layers from the 8th–6th centuries BC, the other two strata are separated either by well-developed soil layers or Roman pavement, and were laid in the 4th century BC and 2nd century BC. It is theorized that the layers of the sediment were created by large landslides. The town was founded around the 7th-6th century BC by the Osci or Oscans and it had already been used as a safe port by Greek and Phoenician sailors. According to Strabo, Pompeii was also captured by the Etruscans, and in recent excavations have shown the presence of Etruscan inscriptions. Pompeii was captured for the first time by the Greek colony of Cumae, allied with Syracuse, in the 5th century BC, the Samnites conquered it, the new rulers imposed their architecture and enlarged the town
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Corinth
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Corinth is a city and former municipality in Corinthia, Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality of Corinth, of which it is the seat and it is the capital of Corinthia. It was founded as Nea Korinthos or New Corinth in 1858 after an earthquake destroyed the settlement of Corinth. Corinth derives its name from Ancient Corinth, a city-state of antiquity, in 1858, the old city, now known as Archaia Korinthos, located 3 kilometres SW of the modern city, was totally destroyed by a magnitude 6.5 earthquake. Nea Korinthos or New Corinth was then built a few kilometers away on the coast of the Gulf of Corinth, a magnitude 6.3 earthquake in 1928 devastated the new city, which was then rebuilt on the same site. It was rebuilt again after a fire in 1933. The Municipality of Corinth had a population of 58,192 according to the 2011 census, the second most populous municipality in the Peloponnese Region after Kalamata. The municipal unit of Corinth had 38,132 inhabitants, of which Corinth itself had 30,176 inhabitants, placing it in place behind Kalamata. The municipal unit of Corinth includes apart from Corinth proper the town of Archaia Korinthos, the town of Examilia, the municipal unit has an area of 102.187 km2. Corinth is an industrial hub at a national level. Corinth Refineries are one of the largest oil refining Industrial complex in Europe, copper cables, petroleum products, leather, medical equipment, marble, gypsum, ceramic tiles, salt, mineral water and beverages, meat products, and gums are produced nearby. As of 2005, a period of deindustrialization has commenced as a large complex, a textile factory. Corinth is a road hub. The A7 toll motorway for Tripoli and Kalamata, branches off the A8/European route E94 toll motorway from Athens at Corinth, Corinth is the main entry point to the Peloponnesian peninsula, the southernmost area of continental Greece. KTEL Korinthias provides intercity bus service in the peninsula and to Athens via the Isthmos station southeast of the city center, local bus service is also available. The city has connected to the Proastiakos, the Athens suburban rail network, since 2005. The port of Corinth, located north of the city centre and close to the northwest entrance of the Corinth Canal, at 3756. 0’ N /2256. 0’ E, serves the needs of industry. It is mainly a cargo exporting facility and it is an artificial harbour (depth approximately 9 metres, protected by a concrete mole
30.
Charlemagne
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Charlemagne or Charles the Great, numbered Charles I, was the King of the Franks from 768, King of the Lombards from 774 and Emperor of the Romans from 800. He united much of Europe during the early Middle Ages and he was the first recognised emperor in western Europe since the fall of the Western Roman Empire three centuries earlier. The expanded Frankish state which Charlemagne founded was called the Carolingian Empire, Charlemagne was the oldest son of Pepin the Short and Bertrada of Laon. He became king in 768 following his fathers death, initially as co-ruler with his brother Carloman I, carlomans sudden death in 771 in unexplained circumstances left Charlemagne as the undisputed ruler of the Frankish Kingdom. He continued his fathers policy towards the papacy and became its protector, removing the Lombards from power in northern Italy and he campaigned against the Saxons to his east, Christianising them upon penalty of death and leading to events such as the Massacre of Verden. Charlemagne reached the height of his power in 800 when he was crowned Emperor of the Romans by Pope Leo III on Christmas Day at Old St. Peters Basilica. Charlemagne has been called the Father of Europe, as he united most of Western Europe for the first time since the Roman Empire and his rule spurred the Carolingian Renaissance, a period of energetic cultural and intellectual activity within the Western Church. All Holy Roman Emperors considered their kingdoms to be descendants of Charlemagnes empire, up to the last Emperor Francis II and these and other machinations led to the eventual split of Rome and Constantinople in the Great Schism of 1054. Charlemagne died in 814, having ruled as emperor for thirteen years and he was laid to rest in his imperial capital of Aachen in what is today Germany. He married at least four times and had three sons, but only his son Louis the Pious survived to succeed him. By the 6th century, the western Germanic Franks had been Christianised, Francia, ruled by the Merovingians, was the most powerful of the kingdoms that succeeded the Western Roman Empire. Following the Battle of Tertry the Merovingians declined into powerlessness, for which they have dubbed the rois fainéants. Almost all government powers were exercised by their chief officer, the mayor of the palace, in 687, Pepin of Herstal, mayor of the palace of Austrasia, ended the strife between various kings and their mayors with his victory at Tertry. He became the governor of the entire Frankish kingdom. Pepin was the grandson of two important figures of the Austrasian Kingdom, Saint Arnulf of Metz and Pepin of Landen, Pepin of Herstal was eventually succeeded by his illegitimate son Charles, later known as Charles Martel. After 737, Charles governed the Franks in lieu of a king, Charles was succeeded in 741 by his sons Carloman and Pepin the Short, the father of Charlemagne. In 743, the brothers placed Childeric III on the throne to curb separatism in the periphery and he was the last Merovingian king. Carloman resigned office in 746, preferring to enter the church as a monk, Pepin brought the question of the kingship before Pope Zachary, asking whether it was logical for a king to have no royal power
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New Model Army
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The New Model Army of England was formed in 1645 by the Parliamentarians in the English Civil War, and was disbanded in 1660 after the Restoration. Its soldiers became full-time professionals, rather than part-time militia, to establish a professional officer corps, the armys leaders were prohibited from having seats in either the House of Lords or House of Commons. This was to encourage their separation from the political or religious factions among the Parliamentarians, many of its common soldiers therefore held Dissenting or radical views unique among English armies. Ultimately, the Armys Generals could rely both on the Armys internal discipline and its religious zeal and innate support for the Good Old Cause to maintain an essentially dictatorial rule. The New Model Army was formed as a result of dissatisfaction among Parliamentarians with the conduct of the Civil War in 1644, there was also increasing dissension among Parliaments generals in the field. Parliament suspected that many of its officers, who were mainly Presbyterians, were inclined to favour peace with King Charles. The Earl of Manchester was one of the prominent members favouring peace, Manchester and Cromwell clashed publicly over this issue several times. Parliaments senior commander, the Earl of Essex, was suspected of lack of determination and was on poor terms with his subordinates. The tensions among the Parliamentarian generals became a public argument after the Second Battle of Newbury. Some of them believed that King Charless army had escaped encirclement after the battle through inaction on the part of some commanders. In response, Parliament directed the Committee of Both Kingdoms, the body that oversaw the conduct of the War. On 19 December, the House of Commons passed the Self-denying Ordinance, originally a separate matter from the establishment of the New Model Army, it soon became intimately linked with it. Once the Self-denying Ordinance became Law, the Earls of Manchester and Essex, on 6 January 1645, the Committee of Both Kingdoms established the New Model Army, appointing Sir Thomas Fairfax as its Captain-General and Sir Philip Skippon as Sergeant-Major General of the Foot. The Self-denying Ordinance took time to pass the House of Lords, although Oliver Cromwell handed over his command of the Armys cavalry when the Ordinance was enacted, Fairfax requested his services when another officer wished to emigrate. Cromwell was commissioned Colonel of Vermuydens former regiment of horse, and was appointed Lieutenant General of the Horse in June, Cromwell and his son-in-law Henry Ireton were two of the only four exceptions to the Self-denying Ordinance, the other two being local commanders in Cheshire and North Wales. They were allowed to serve under a series of temporary commissions that were continually extended. They were intended to reduce the remaining Royalist garrisons in their areas, some of their regiments were reorganised and incorporated into the New Model Army during and after the Second English Civil War. Although the cavalry regiments were well up to strength and there was no shortage of volunteers
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Cochineal
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The cochineal is a scale insect in the suborder Sternorrhyncha, from which the natural dye carmine is derived. A primarily sessile parasite native to tropical and subtropical South America as well as Mexico and Arizona and these insects are found on the pads of prickly pear cacti, then are brushed off and dried. The insect produces carminic acid that deters predation by other insects, carminic acid, typically 17-24% of dried insects weight, can be extracted from the body and eggs, then mixed with aluminium or calcium salts to make carmine dye, also known as cochineal. Today, carmine is primarily used as a colorant in food, the carmine dye was used in Central America in the 15th century for coloring fabrics and became an important export good during the colonial period. After synthetic pigments and dyes such as alizarin were invented in the late 19th century, some towns in the Mexican state of Oaxaca are still working in handmade textiles using this cochineal. The primary biological distinctions between species are minor differences in host plant preferences, in addition to different geographic distributions. Cochineal is probably from French cochenille, Spanish cochinilla, Latin coccinus, meaning scarlet-colored, and Latin coccum, meaning berry yielding scarlet dye. See also the word kermes which is the source of a similar but weaker Mediterranean dye also called crimson. Some sources identify the Spanish source word for cochineal as cochinilla wood louse, Cochineal dye was used by the Aztec and Maya peoples of Central and North America. Eleven cities conquered by Montezuma in the 15th century paid a tribute of 2000 decorated cotton blankets and 40 bags of cochineal dye each. Production of cochineal is depicted in Codex Osuna, during the colonial period, the production of cochineal grew rapidly. Produced almost exclusively in Oaxaca by indigenous producers, cochineal became Mexicos second-most valued export after silver, soon after the Spanish conquest of the Aztec Empire, it began to be exported to Spain, and by the 17th century was a commodity traded as far away as India. The dyestuff was consumed throughout Europe and was so prized, its price was regularly quoted on the London. In 1777, French botanist Nicolas-Joseph Thiéry de Menonville, presenting himself as a physician, smuggled the insects. This particular collection failed to thrive and ultimately died out, leaving the Mexican monopoly intact, after the Mexican War of Independence in 1810–1821, the Mexican monopoly on cochineal came to an end. Large-scale production of cochineal emerged, especially in Guatemala and the Canary Islands, it was cultivated in Spain. The delicate manual labour required for the breeding of the insect could not compete with the methods of the new industry. The tuna blood dye stopped being used and trade in cochineal almost totally disappeared in the course of the 20th century, the breeding of the cochineal insect has been done mainly for the purposes of maintaining the tradition rather than to satisfy any sort of demand
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Red coat (military uniform)
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Red coat or Redcoat is a historical item of military clothing used widely, though not exclusively worn, by most regiments of the British Army from the 17th to the 20th centuries. From the mid-17th century to the 19th century, the uniform of most British soldiers included a red coat or coatee. From 1873 onwards, the more vivid shade of scarlet was adopted for all ranks, having previously been worn only by officers, sergeants, the Red Coat has evolved from being the British infantrymans ordinary uniform to a garment retained only for ceremonial purposes. Its official adoption dates from February 1645, when the Parliament of England passed the New Model Army ordinance. The new English Army was formed of 22,000 men, divided into 12 foot regiments of 600 men each, one regiment of 1000 men. The infantry regiments wore coats of Venetian red with white facings, a contemporary comment on the New Model Army dated 7 May 1645 stated the men are Redcoats all, the whole army only are distinguished by the several facings of their coats. There had been many isolated instances of red military clothing pre-dating its general adoption by the New Model Army, the uniforms of the Yeoman of the Guard and the Yeomen Warders have traditionally been in Tudor red and gold. The Gentlemen Pensioners of James I had worn red with yellow feathers, at Edgehill, the first battle of the Civil War, the Kings people had worn red coats, as had at least two Parliamentary regiments. None of these constituted the national uniform that the red coat was later to become. However, in Ireland during the reign of Elizabeth, the soldiers of the queens Lord Lieutenant of Ireland were referred to as red coats by the native Irish from the colour of their uniforms and this is clear from both Irish and English primary sources. Note the Irish word is casóg but the word may be translated as coat, cloak, or even uniform and this is not an isolated reference. OSullivan alludes to two other encounters in which the Irish won the day against English red coats, the other relates to a rout by William Burke, Lord of Bealatury in 1599 of English recruits clad in red coats. English sources confirm that Crown troops in Ireland wore red coats/cloaks/uniforms/clothing, outside of Ireland, the English Red Coat made its first appearance on a European continental battlefield at the Battle of the Dunes in 1658. A Protectorate army had landed at Calais the previous year and every man had a new red coat. The English name from the battle comes from the major engagement carried out by the red-coats, to the surprise of continental observers they stormed sand-dunes 150 feet high fighting experienced Spanish soldiers from their summits with musket fire and push of pike. The adoption and continuing use of red by most British/English soldiers after the Restoration was the result of rather than policy. Red was by no means universal at first, with grey, There is no known basis for the myth that red coats were favoured because they did not show blood stains. Blood does in fact show on red clothing as a black stain, prior to 1707 colonels of regiments made their own arrangements for the manufacture of uniforms under their command
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Mordant
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A mordant or dye fixative is a substance used to set dyes on fabrics or tissue sections by forming a coordination complex with the dye which then attaches to the fabric or tissue. It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations, the term mordant comes from the present participle of French mordre, to bite. In the past, it was thought that a mordant helped the dye bite onto the fiber so that it would hold fast during washing, a mordant is often a polyvalent metal ion. The resulting coordination complex of dye and ion is colloidal and can be acidic or alkaline. Mordants include tannic acid, alum, urine, chrome alum, sodium chloride, iodine is often referred to as a mordant in Gram stains, but is in fact a trapping agent. The three methods used for mordanting are, Pre-mordanting, The substrate is treated with the mordant, meta-mordanting, The mordant is added in the dye bath itself. Post-mordanting, The dyed material is treated with a mordant, the type of mordant used changes the shade obtained after dyeing and also affects the fastness property of the dye. The stability of the mordant or dye lake or both, the formation of a stable dye lake means that the mordant can be added in the dye without risk of losing the dye properties. Dye results can also rely on the mordant chosen as the introduction of the mordant into the dye will have an effect on the final color. Each dye can have different reactions to each mordant, for example, cochineal scarlet, or Dutch scarlet as it came to be known, used cochineal along with a tin mordant to create a brilliant orange-hued red. Residual iron mordant can damage or fade fabric, producing dye rot, the dye lake is an insoluble molecule formed when the complex of dye and mordant are combined, which then attaches to the substrate. Mordants increase the fastness of the dye since the molecule is now bonded to the fibre. The term lake is derived from the term lac, the secretions of the Indian wood insect Laccifer lacca and this is the same insect from which shellac is obtained. The type of mordant used can change the colour of both the dye-plus-mordant solution and influence the shade of the final product, unlike cotton, wool is highly receptive toward mordants. Due to its amphoteric nature wool can absorb acids and bases with equal efficiency, when wool is treated with a metallic salt it hydrolyses the salt into an acidic and basic component. The basic component is absorbed at –COOH group and the component is removed during washing. Wool also has a tendency to absorb fine precipitates from solutions, like wool, silk is also amphoteric and can absorb both acids as well as bases. However, wool has thio groups from the amino acid
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Lake pigment
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A lake pigment is a pigment manufactured by precipitating a dye with an inert binder, or mordant, usually a metallic salt. Unlike vermilion, ultramarine, and other pigments made from ground minerals, manufacturers and suppliers to artists and industry frequently omit the lake designation in the name. Many lake pigments are fugitive because the involved are not lightfast. Red lakes were important in Renaissance and Baroque paintings, they were often used as translucent glazes to portray the colors of rich fabrics. This sense of lake is unconnected with lake meaning body of water and it has the same root as the word lacquer, and comes originally from the Hindi word lakh, through the Arabic word lakk and the Persian word lak. Many lake pigments are azo dyes and they characteristically have sulfonate and sometimes carboxylate substituents, which confer negative charge to the chromophore. The metallic salt or binder used must be inert and insoluble in the vehicle, the organic component of the dye determines which wavelengths are absorbed and reflected by the resulting precipitate. In ancient times chalk, white clay, and crushed bones were used as sources of the calcium salts. The salts that are used today include barium sulfate, calcium sulfate, aluminium hydroxide. Lake pigments have a history in decoration and the arts. Some have been produced for thousands of years and traded over long distances. The red lakes were important in the history of art, because they were translucent, they were often used in layers of glazes over a more opaque red to create a deep. They were very often used by Titian and other Venetian artists of the 16th century to depict fine draperies, indigo lake was originally produced from the leaves of woad, and was known in ancient Egypt. In the late Middle Ages, a fashion for woad as a textile dye led to overplanting, after trade routes opened to the east, indigo was imported from India as a substitute for woad, and the cultivation of woad became uneconomical in Europe. Today, the blue dye known as indigo once produced from woad. The dye and pigment are both fugitive, rose madder lake, originally from the root of the madder plant, is also known as alizarin crimson in its synthetic form. Since rose madder is fugitive when exposed to light, its use has largely superseded, even in synthetic form. Carmine lake was produced from the cochineal insect, native to Central
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