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.
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
6.
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
7.
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
8.
Odor
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An odor or odour or fragrance is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors, the terms fragrance and aroma are used primarily by the food and cosmetic industry to describe a pleasant odor, and are sometimes used to refer to perfumes, and to describe floral scent. In contrast, malodor, stench, reek, and stink are used specifically to describe unpleasant odor, the term smell is used for both pleasant and unpleasant odors. In the United Kingdom, odour refers to scents in general, the sense of smell gives rise to the perception of odors, mediated by the olfactory nerve. The olfactory receptor cells are present in the olfactory epithelium. There are millions of olfactory receptor neurons that act as sensory signaling cells, each neuron has cilia in direct contact with air. The olfactory nerve is considered the smell mediator, the axon connects the brain to the external air, odorous molecules act as a chemical stimulus. Molecules bind to receptor proteins extended from cilia, initiating an electric signal, thus, by using a chemical that binds to copper in the mouse nose, so that copper wasn’t available to the receptors, the authors showed that the mice couldnt detect the thiols. However, these also found that MOR244-3 lacks the specific metal ion binding site suggested by Suslick. When the signal reaches a threshold, the fires, sending a signal traveling along the axon to the olfactory bulb. Interpretation of the begins, relating the smell to past experiences. The olfactory bulb acts as a station connecting the nose to the olfactory cortex in the brain. Olfactory information is processed and projected through a pathway to the central nervous system. Odor sensation usually depends on the concentration available to the olfactory receptors, the olfactory system does not interpret a single compound, but instead the whole odorous mix, not necessarily corresponding to concentration or intensity of any single constituent. The widest range of odors consists of compounds, although some simple compounds not containing carbon, such as hydrogen sulfide. The perception of an effect is a two-step process. First, there is the part, the detection of stimuli by receptors in the nose. The stimuli are processed by the region of the brain which is responsible for olfaction
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.
Vapor pressure
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Vapor pressure or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquids evaporation rate and it relates to the tendency of particles to escape from the liquid. A substance with a vapor pressure at normal temperatures is often referred to as volatile. The pressure exhibited by vapor present above a surface is known as vapor pressure. As the temperature of a liquid increases, the energy of its molecules also increases. As the kinetic energy of the molecules increases, the number of molecules transitioning into a vapor also increases, the vapor pressure of any substance increases non-linearly with temperature according to the Clausius–Clapeyron relation. The atmospheric pressure boiling point of a liquid is the temperature at which the pressure equals the ambient atmospheric pressure. With any incremental increase in temperature, the vapor pressure becomes sufficient to overcome atmospheric pressure. Bubble formation deeper in the liquid requires a pressure, and therefore higher temperature. More important at shallow depths, is the temperature required to start bubble formation. The surface tension of the wall lead to an overpressure in the very small initial bubbles. Thus, thermometer calibration should not rely on the temperature in boiling water, the vapor pressure that a single component in a mixture contributes to the total pressure in the system is called partial pressure. Vapor pressure is measured in the units of pressure. The International System of Units recognizes pressure as a unit with the dimension of force per area. One pascal is one newton per square meter, experimental measurement of vapor pressure is a simple procedure for common pressures between 1 and 200 kPa. Most accurate results are obtained near the point of substances. Better accuracy is achieved when care is taken to ensure that the entire substance and this is often done, as with the use of an isoteniscope, by submerging the containment area in a liquid bath. Very low vapor pressures of solids can be measured using the Knudsen effusion cell method, the Antoine equation is a mathematical expression of the relation between the vapor pressure and the temperature of pure liquid or solid substances
14.
Immediately dangerous to life or health
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Examples include smoke or other poisonous gases at sufficiently high concentrations. It is calculated using the LD50 or LC50, IDLH values are often used to guide the selection of breathing apparatus that are made available to workers or firefighters in specific situations. The NIOSH definition does not include oxygen deficiency although atmosphere-supplying breathing apparatus is also required, examples include high altitudes and unventilated, confined spaces. It also uses the broader term impair, rather than prevent, for example, blinding but non-toxic smoke could be considered IDLH under the OSHA definition if it would impair the ability to escape a dangerous but not life-threatening atmosphere. The OSHA definition is part of a standard, which is the minimum legal requirement. If the concentration of substances is IDLH, the worker must use the most reliable respirators. Such respirators should not use cartridges or canister with the sorbent, in addition, the respirator must maintain positive pressure under the mask during inspiration, as this will prevent the leakage of unfiltered air through the gaps. The following examples are listed in reference to IDLH values, NIOSH IDLH site 1910.134 Respiratory protection definitions
15.
2,4-Dichlorophenoxyacetic acid
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2, 4-Dichlorophenoxyacetic acid is an organic compound with the chemical formula C8H6Cl2O3. It can be found in commercial lawn herbicide mixtures, and is widely used as a weedkiller on cereal crops, pastures. Over 1,500 herbicide products contain 2, 4-D as an active ingredient,2, 4-D is a possible carcinogen per WHO. Some ester forms are highly toxic to fish and other aquatic life,2, 4-D was one of the ingredients in Agent Orange, a herbicide widely used during the Vietnam War. However, another ingredient in Agent Orange,2,4, 5-T,2, 4-D is primarily used as a selective herbicide which kills many terrestrial and aquatic broadleaf weeds, but not grasses. It acts by mimicking the action of the plant growth hormone auxin, because it was discovered in the 1940s, there is no longer a patent governing the manufacture and sale of 2, 4-D, and any company is free to produce it. Thus, it is sold in formulations under a wide variety of brand names. 2, 4-D can be found in commercial lawn herbicide mixtures, over 1,500 herbicide products contain 2, 4-D as an active ingredient. A wide variety of different sectors use products containing 2, 4-D to kill weeds, in agriculture, it was the first herbicide found to be capable of selectively killing weeds but not crops. It has been used since 1945 to control broad-leafed weeds in pastures, orchards, cereals, in particular, have excellent tolerance to 2, 4-D when it is applied before planting. 2, 4-D is the cheapest way for farmers to control winter annual weeds by spraying in the fall and this is particularly effective before planting beans, peas, lentils and chickpeas. In domestic lawn and garden maintenance,2, 4-D is commonly used for weed control in lawns and it is used to kill unwanted weeds such as dandelions, plantain, clover and chickweed. In forestry, it is used for treatment, trunk injection. Along roadways, railways, and power lines it is used to control weeds and brush which might interfere with safe operation, along waterways it is used to control aquatic weeds that might interfere with boating, fishing and swimming or clog irrigation and hydroelectric equipment. A2010 monitoring study conducted in the US and Canada found that current exposures to 2,2,4 D has been used in laboratories for plant research as a supplement in plant cell culture media such as MS medium since at least 1962. 2, 4-D is used in plant cell cultures as a dedifferentiation hormone and it is classified as an auxin plant hormone derivative. Some scientists are experimenting with soaking tomatoes in 2, 4-D as a way of slowing their ripening after they are harvested. Men who work with 2, 4-D are at risk for abnormally shaped sperm and thus fertility problems, according to the U. S. Environmental Protection Agency, The toxicity of 2, 4-D depends on its chemical forms, including salts, esters, and an acid form
16.
Auxin
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Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins have a role in coordination of many growth and behavioral processes in the plants life cycle and are essential for plant body development. Auxins and their role in plant growth were first described by the Dutch scientist Frits Warmolt Went, Kenneth V. Thimann was the first to isolate one of these phytohormones and determine its chemical structure as indole-3-acetic acid. Went and Thimann co-authored a book on plant hormones, Phytohormones, Auxins were the first of the major plant hormones to be discovered. They derive their name from the Greek word αυξειν, auxin is present in all parts of a plant, although in very different concentrations. The concentration in each position is crucial information, so it is subject to tight regulation through both metabolism and transport. The pattern of auxin distribution within the plant is a key factor for plant growth, its reaction to its environment and it is achieved through very complex and well coordinated active transport of auxin molecules from cell to cell throughout the plant body — by the so-called polar auxin transport. Thus, a plant can react to external conditions and adjust to them, Auxins typically act in concert with, or in opposition to, other plant hormones. For example, the ratio of auxin to cytokinin in certain plant tissues determines initiation of root versus shoot buds, on the molecular level, all auxins are compounds with an aromatic ring and a carboxylic acid group. The most important member of the family is indole-3-acetic acid, which generates the majority of auxin effects in intact plants. However, molecules of IAA are chemically labile in aqueous solution, five naturally occurring auxins in plants include indole-3-acetic acid, 4-chloroindole-3-acetic acid, phenylacetic acid, indole-3-butyric acid, and indole-3-propionic acid. Alongside endogenous auxins, scientists and manufacturers have developed many synthetic compounds with auxinic activity, synthetic auxin analogs include 1-naphthaleneacetic acid,2, 4-dichlorophenoxyacetic acid, and many others. Some synthetic auxins, such as 2, 4-D and 2,4, broad-leaf plants, such as dandelions, are much more susceptible to auxins than narrow-leaf plants such as grasses and cereal crops, so these synthetic auxins are valuable as synthetic herbicides. In 1881, Charles Darwin and his son Francis performed experiments on coleoptiles, the experiment exposed the coleoptile to light from a unidirectional source, and observed that they bend towards the light. By covering various parts of the coleoptiles with an opaque cap, the Darwins discovered that light is detected by the coleoptile tip. However the seedlings showed no signs of development towards light if the tip was covered with an opaque cap, in 1913, Danish scientist Peter Boysen-Jensen demonstrated that the signal was not transfixed but mobile. He separated the tip from the remainder of the coleoptile by a cube of gelatine which prevented cellular contact, the seedlings responded normally bending towards the light. However, when the tip was separated by an impermeable substance, in 1928, the Dutch botanist Frits Warmolt Went showed that a chemical messenger diffuses from coleoptile tips
17.
Herbicide
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Herbicide, also commonly known as weedkillers, are chemical substances used to control unwanted plants. Apart from selective/non-selective, other important distinctions include persistence, means of uptake, Herbicides have also been used in warfare and conflict. Modern herbicides are often mimics of natural plant hormones which interfere with growth of the target plants. The term organic herbicide has come to mean herbicides intended for organic farming, due to herbicide resistance - a major concern in agriculture - a number of products also combine herbicides with different means of action. In the US in 2007, about 83% of all herbicide usage, in 2007, world pesticide expenditures totaled about $39.4 billion, herbicides were about 40% of those sales and constituted the biggest portion, followed by insecticides, fungicides, and other types. Smaller quantities are used in forestry, pasture systems, and management of areas set aside as wildlife habitat, prior to the widespread use of chemical herbicides, cultural controls, such as altering soil pH, salinity, or fertility levels, were used to control weeds. Mechanical control was used to control weeds. The first modern herbicide,2, 4-D, was first discovered and synthesized by W. G. Templeman at Imperial Chemical Industries, in 1940, he showed that Growth substances applied appropriately would kill certain broad-leaved weeds in cereals without harming the crops. By 1941, his team succeeded in synthesizing the chemical, in the same year, Pokorny in the US achieved this as well. Independently, a team under Juda Hirsch Quastel, working at the Rothamsted Experimental Station made the same discovery, Quastel was tasked by the Agricultural Research Council to discover methods for improving crop yield. By analyzing soil as a system, rather than an inert substance. Quastel was able to quantify the influence of plant hormones, inhibitors and other chemicals on the activity of microorganisms in the soil. While the full work of the unit remained secret, certain discoveries were developed for use after the war, including the 2. When it was released in 1946, it triggered a worldwide revolution in agricultural output. It allowed for greatly enhanced weed control in wheat, maize, rice, and similar cereal crops, because it kills dicots. The low cost of 2, 4-D has led to continued usage today, like other acid herbicides, current formulations use either an amine salt or one of many esters of the parent compound. These are easier to handle than the acid, atrazine does not break down readily after being applied to soils of above neutral pH. Under alkaline soil conditions, atrazine may be carried into the profile as far as the water table by soil water following rainfall causing the aforementioned contamination
18.
Agent Orange
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Agent Orange is a herbicide and defoliant chemical. It is widely known for its use by the U. S. military as part of its herbicidal warfare program, Operation Ranch Hand and it was a mixture of equal parts of two herbicides,2,4, 5-T and 2, 4-D. The chemical damaged the health of people who came into contact with it as well as extensively contaminated the environment, the defoliant caused grievous health consequences for those who came in contact. Up to 4 million people in Vietnam were affected and 1 million people have illnesses, the chemical has damaged the genes, giving descendants with deformities. The US government has documented cases of leukemia, Hodgkins lymphoma as well as various kinds of cancer in veterans. Agent Orange caused enormous damage in Vietnam. Over 3,100,000 hectares of forest were defoliated, defoliants eroded tree cover and seedling forest stock, making reforestation difficult in numerous areas. Animal species diversity sharply reduced in contrast with unsprayed areas, the aftermath of the use of Agent Orange in Vietnam resulted in massive legal consequences. The United Nations ratified Resolution 31/72 and the Environmental Modification Convention, lawsuits filed on behalf of veterans as well as Vietnamese veterans sought compensation for damages. Agent Orange was to a lesser extent used outside Vietnam, some countries saw testing, while other countries such as Canada and Brazil used the herbicide to clear out sections of land for agriculture. Land in Laos and Cambodia was sprayed with Agent Orange because forests on the border with Vietnam were used by the Vietcong, the dioxin TCDD is significant contaminant of Agent Orange. TCDD is the most toxic of the dioxins, and is classified as a carcinogen by the US Environmental Protection Agency. Agent Orange dries quickly after spraying and breaks down within hours to days when exposed to sunlight and is no longer harmful, due to its fat-soluble nature, dioxin enters through physical contact or ingestion. Dioxin easily accumulates in the food chain, Dioxin enters the body by attaching to a protein called the aryl hydrocarbon receptor, a transcription factor. When dioxin binds to AhR, the moves to the nucleus. Several herbicides were discovered as part of efforts by the USA and these included 2, 4-D,2,4, 5-T, MCPA, and isopropyl phenylcarbamate. He discovered both that 2,3, 5-triiodobenzoic acid would speed up the flowering of soybeans and that in higher concentrations it would defoliate the soybeans, from these studies arose the concept of using aerial applications of herbicides to destroy enemy crops to disrupt their food supply. In early 1945, the U. S. Army ran tests of various 2, 4-D and 2,4, 5-T mixtures at the Bushnell Army Airfield in Florida
19.
Malayan Emergency
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Malayan Emergency was the colonial governments term for the conflict. The MNLA termed it the Anti-British National Liberation War, the rubber plantations and tin-mining industries had pushed for the use of the term emergency since their losses would not have been covered by Lloyds insurers if it had been termed a war. Despite the communists defeat in 1960, communist leader Chin Peng renewed the insurgency against the Malaysian government in 1967 and he fled to exile in Thailand, where he lived until his death on 16 September 2013. The Malayan economy relied on the export of tin and rubber, when the British took control of the Malayan economy, they imposed taxes on some Malayan goods, affecting their traditional industries. This led to an increase in poverty for the Malayan people, many Chinese people found employment in tin mines or fields responsible for the trade of materials. This heightened inter-ethnic tensions as the Malay people found that ethnic Chinese had replaced them in certain jobs and this forced many Malays into the rubber industry, which in turn was heavily dependent upon volatile world prices. Economic tension intensified during the Second World War. The Japanese occupation of Malaya began in 1941 and from that point onwards the “export of primary products was limited to the small amounts required for the Japanese economy. ”This led to large areas of rubber plantations being abandoned. The latter was progressively affected by a shortage of parts for machines. Rice imports, which made up a portion of the Malayan diet, fell rapidly due to limited trade. Many people believed that the British would soon return and ‘save’ them so they did not attempt to learn the skills that would be essential for survival. This then led to famine in Malaya from 1942. The withdrawal of Japan at the end of World War II left the British Malayan economy disrupted, problems included unemployment, low wages, and high levels of food inflation, well above the healthy rate of 2–3%. The Malayan Communist Party began to use the failing economy as a tool of propaganda against the British, the British had not addressed the underlying economic problems that were now worse within Malaya than they had ever been. There was considerable labour unrest and a number of strikes occurred between 1946 and 1948. One example of this was a 24-hour general strike organised by the MCP on 29 January 1946, during this time, the British administration was attempting to organise Malayas economy, as revenue from Malayas tin and rubber industries was important to Britains own post-war recovery. Protesters were dealt with harshly, by measures including arrests and deportations, in turn, protesters became increasingly militant. In 1947, alone, the communists in Malaya organised a further 300 strikes, on 16 June 1948, the first overt act of the war took place when three European plantation managers were killed at Sungai Siput, Perak
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Vietnam War
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It was the second of the Indochina Wars and was officially fought between North Vietnam and the government of South Vietnam. The war is considered a Cold War-era proxy war. As the war continued, the actions of the Viet Cong decreased as the role. U. S. and South Vietnamese forces relied on air superiority and overwhelming firepower to conduct search and destroy operations, involving ground forces, artillery, in the course of the war, the U. S. conducted a large-scale strategic bombing campaign against North Vietnam. The North Vietnamese government and the Viet Cong were fighting to reunify Vietnam and they viewed the conflict as a colonial war and a continuation of the First Indochina War against forces from France and later on the United States. The U. S. government viewed its involvement in the war as a way to prevent a communist takeover of South Vietnam and this was part the domino theory of a wider containment policy, with the stated aim of stopping the spread of communism. Beginning in 1950, American military advisors arrived in what was then French Indochina, U. S. involvement escalated in the early 1960s, with troop levels tripling in 1961 and again in 1962. Regular U. S. combat units were deployed beginning in 1965, despite the Paris Peace Accord, which was signed by all parties in January 1973, the fighting continued. In the U. S. and the Western world, a large anti-Vietnam War movement developed as part of a larger counterculture, the war changed the dynamics between the Eastern and Western Blocs, and altered North–South relations. Direct U. S. military involvement ended on 15 August 1973, the capture of Saigon by the North Vietnamese Army in April 1975 marked the end of the war, and North and South Vietnam were reunified the following year. The war exacted a huge human cost in terms of fatalities, estimates of the number of Vietnamese soldiers and civilians killed vary from 966,000 to 3.8 million. Some 240, 000–300,000 Cambodians,20, 000–62,000 Laotians, and 58,220 U. S. service members died in the conflict. Various names have applied to the conflict. Vietnam War is the most commonly used name in English and it has also been called the Second Indochina War and the Vietnam Conflict. As there have been several conflicts in Indochina, this conflict is known by the names of its primary protagonists to distinguish it from others. In Vietnamese, the war is known as Kháng chiến chống Mỹ. It is also called Chiến tranh Việt Nam, France began its conquest of Indochina in the late 1850s, and completed pacification by 1893. The 1884 Treaty of Huế formed the basis for French colonial rule in Vietnam for the seven decades
21.
2,3,7,8-Tetrachlorodibenzodioxin
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2,3,7, 8-Tetrachlorodibenzo-p-dioxin is a polychlorinated dibenzo-p-dioxin with the chemical formula C 12H 4Cl 4O2. TCDD is a solid with no distinguishable odor at room temperature. It is usually formed as a product in organic synthesis. TCDD is the most potent compound of its series and became known as a contaminant in Agent Orange, TCDD was released into the environment in the Seveso disaster. It is a persistent environmental contaminant usually present in a mixture of dioxin-like compounds. The Expert Group of the World Health Organization considered developmental toxicity as the most pertinent risk of dioxins to human beings, because people are usually exposed simultaneously to a number of dioxin-like chemicals, a more detailed account is given at dioxins and dioxin-like compounds. TCDD was classified in 1997 by the International Agency for Research on Cancer as a carcinogen for humans, in the occupational cohort studies available for the classification, the risk, even at very high exposures, was weak and borderline detectable. Therefore, human data were not deemed sufficient, and the classification was, in essence, based on animal experiments and this has been criticized as a deviation from IARC classification rules. It is much debated whether TCDD is carcinogenic only at doses which also cause toxic damage of tissues. Moreover, a recent review concludes that, after 1997, further studies do not support an association between TCDD exposure and cancer risk. New studies include the update of Vietnam veteran studies from Ranch Hand operation, there is also direct epidemiological evidence that TCDD is not carcinogenic at low doses, and in some studies cancer risk has even decreased. This is called a J-shape dose-response, low doses decrease the risk, TCDD and dioxin-like compounds act via a specific receptor present in all cells, the aryl hydrocarbon receptor. Genes of enzymes activating the breakdown of foreign and often toxic compounds are examples of such genes. TCDD increases the breaking down, e. g. carcinogenic polycyclic hydrocarbons such as benzopyrene. These polycyclic hydrocarbons also activate the AH receptor, but less than TCDD, even many natural compounds present in vegetables cause some activation of the AH receptor. This phenomenon can be viewed as adaptive and beneficial, because it protects the organism from toxic and carcinogenic substances, excessive and persistent stimulation of AH receptor, however, leads to a multitude of adverse effects. The physiological function of the AH receptor has been the subject of continuous research, one obvious function is to increase the activity of enzymes breaking down foreign chemicals or normal chemicals of the body as needed. There may be functions, however, related to growth of various organs or other regulatory functions
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Carcinogen
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A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes, several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise in both natural and synthetic substances. Carcinogens are not necessarily immediately toxic, thus their effect can be insidious, Cancer is any disease in which normal cells are damaged and do not undergo programmed cell death as fast as they divide via mitosis. Usually, severe DNA damage leads to apoptosis, but if the cell death pathway is damaged. Aflatoxin B1, which is produced by the fungus Aspergillus flavus growing on stored grains, nuts and peanut butter, is an example of a potent, certain viruses such as hepatitis B and human papilloma virus have been found to cause cancer in humans. The first one shown to cause cancer in animals is Rous sarcoma virus, other infectious organisms which cause cancer in humans include some bacteria and helminths. Dioxins and dioxin-like compounds, benzene, kepone, EDB, vinyl chloride, from which PVC is manufactured, is a carcinogen and thus a hazard in PVC production. Co-carcinogens are chemicals that do not necessarily cause cancer on their own, after the carcinogen enters the body, the body makes an attempt to eliminate it through a process called biotransformation. The purpose of these reactions is to make the carcinogen more water-soluble so that it can be removed from the body, however, in some cases, these reactions can also convert a less toxic carcinogen into a more toxic carcinogen. DNA is nucleophilic, therefore soluble carbon electrophiles are carcinogenic, because DNA attacks them, for example, some alkenes are toxicated by human enzymes to produce an electrophilic epoxide. DNA attacks the epoxide, and is bound permanently to it and this is the mechanism behind the carcinogenicity of benzopyrene in tobacco smoke, other aromatics, aflatoxin and mustard gas. Carcinogenicity of radiation depends on the type of radiation, type of exposure, for example, alpha radiation has low penetration and is not a hazard outside the body, but emitters are carcinogenic when inhaled or ingested. Low-level ionizing radiation may induce irreparable DNA damage leading to pre-mature aging, not all types of electromagnetic radiation are carcinogenic. Higher-energy radiation, including radiation, x-rays, and gamma radiation, generally is carcinogenic. For most people, ultraviolet radiations from sunlight is the most common cause of skin cancer, in Australia, where people with pale skin are often exposed to strong sunlight, melanoma is the most common cancer diagnosed in people aged 15–44 years. Substances or foods irradiated with electrons or electromagnetic radiation are not carcinogenic, in contrast, non-electromagnetic neutron radiation produced inside nuclear reactors can produce secondary radiation through nuclear transmutation. Chemicals used in processed and cured such as some brands of bacon, sausages
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Persistent organic pollutant
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Persistent organic pollutants are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of their persistence, POPs bioaccumulate with potential significant impacts on human health, many POPs are currently or were in the past used as pesticides, solvents, pharmaceuticals, and industrial chemicals. Although some POPs arise naturally, for example volcanoes and various biosynthetic pathways, POPs typically are halogenated organic compounds and as such exhibit high lipid solubility. For this reason, they bioaccumulate in fatty tissues, halogenated compounds also exhibit great stability reflecting the nonreactivity of C-Cl bonds toward hydrolysis and photolytic degradation. The stability and lipophilicity of organic compounds often correlates with their halogen content, compounds that make up POPs are also classed as PBTs or TOMPs. This results in accumulation of POPs in areas far from where they were used or emitted, specifically environments where POPs have never been introduced such as Antarctica, POPs can be present as vapors in the atmosphere or bound to the surface of solid particles. POPs have low solubility in water but are captured by solid particles. POPs are not easily degraded in the environment due to their stability, bioaccumulation of POPs is typically associated with the compounds high lipid solubility and ability to accumulate in the fatty tissues of living organisms for long periods of time. Persistent chemicals tend to have higher concentrations and are eliminated more slowly, thus POPs not only persist in the environment, but also as they are taken in by animals they bioaccumulate, increasing their concentration and toxicity in the environment. The Stockholm Convention was adopted and put into practice by the United Nations Environment Programme on May 22,2001, the UNEP decided that POP regulation needed to be addressed globally for the future. The purpose statement of the agreement is to human health. As of 2014, there are 179 countries in compliance with the Stockholm convention, the convention and its participants have recognized the potential human and environmental toxicity of POPs. They recognize that POPs have the potential for long range transport, the convention seeks to study and then judge whether or not a number of chemicals that have been developed with advances in technology and science can be categorized as POPs or not. The initial meeting in 2001 made a preliminary list, termed the “dirty dozen, as of 2014, the United States of America has signed the Stockholm Convention but has not ratified it. There are a handful of countries that have not ratified the convention. In May 1995, the United Nations Environment Programme Governing Council investigated POPs, aldrin, an insecticide used in soils to kill termites, grasshoppers, Western corn rootworm, and others, is also known to kill birds, fish, and humans. Humans are primarily exposed to aldrin through dairy products and animal meats, chlordane has been postulated to affect the human immune system and is classified as a possible human carcinogen. Chlordane air pollution is believed the route of humane exposure
24.
United States Department of Agriculture
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Approximately 80% of USDAs $140 billion budget goes to the Food and Nutrition Service program. The largest component of the FNS budget is the Supplemental Nutrition Assistance Program, after the resignation of Thomas Vilsack on January 13,2017 and the departure of President Barack Obama from office on January 20,2017, the acting Secretary of Agriculture is Michael Young. Activities in this include the Supplemental Nutrition Assistance Program, which provides healthy food to over 40 million low-income. The USDA also is concerned with assisting farmers and food producers with the sale of crops and it plays a role in overseas aid programs by providing surplus foods to developing countries. This aid can go through USAID, foreign governments, international bodies such as World Food Program, the Agricultural Act of 1949, section 416 and Agricultural Trade Development and Assistance Act of 1954, also known as Food for Peace, provides the legal basis of such actions. The USDA is a partner of the World Cocoa Foundation, early in its history, the economy of the United States was largely agrarian. Officials in the government had long sought new and improved varieties of seeds, plants. In 1837 Henry Leavitt Ellsworth, a Yale-educated attorney interested in improving agriculture, became Commissioner of Patents and he began collecting and distributing new varieties of seeds and plants through members of the Congress and agricultural societies. In 1839, Congress established the Agricultural Division within the Patent Office and allotted $1,000 for the collection of agricultural statistics, Ellsworth was called the Father of the Department of Agriculture. In 1849, the Patent Office was transferred to the newly created Department of the Interior, in the ensuing years, agitation for a separate bureau of agriculture within the department or a separate department devoted to agriculture kept recurring. Lincoln called it the peoples department, in the 1880s, varied advocacy groups were lobbying for Cabinet representation. Business interests sought a Department of Commerce and Industry, and farmers tried to raise the Department of Agriculture to Cabinet rank, finally, on February 9,1889, President Grover Cleveland signed a bill into law elevating the Department of Agriculture to Cabinet level. In 1887, the Hatch Act provided for the funding of agricultural experiment stations in each state. The Smith-Lever Act of 1914 then funded cooperative extension services in each state to teach agriculture, home economics, with these and similar provisions, the USDA reached out to every county of every state. During the Great Depression, farming remained a way of life for millions of Americans. The Department of Agricultures Bureau of Home Economics, established in 1923, published shopping advice and recipes to stretch family budgets and make food go farther. USDA helped ensure that continued to be produced and distributed to those who needed it, assisted with loans for small landowners. The Department of Agriculture was authorized a budget for Fiscal Year 2015 of $139.7 billion, the Washington Post reports that he said There are days when I have literally nothing to do, he recalled thinking as he weighed his decision to quit
25.
United States Environmental Protection Agency
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The EPA was proposed by President Richard Nixon and began operation on December 2,1970, after Nixon signed an executive order. The order establishing the EPA was ratified by committee hearings in the House, the agency is led by its Administrator, who is appointed by the president and approved by Congress. The current administrator is Scott Pruitt, the EPA is not a Cabinet department, but the administrator is normally given cabinet rank. The EPA has its headquarters in Washington, D. C. regional offices for each of the ten regions. The agency conducts environmental assessment, research, and education and it has the responsibility of maintaining and enforcing national standards under a variety of environmental laws, in consultation with state, tribal, and local governments. It delegates some permitting, monitoring, and enforcement responsibility to U. S. states, EPA enforcement powers include fines, sanctions, and other measures. The agency also works with industries and all levels of government in a variety of voluntary pollution prevention programs. In 2016, the agency had 15,376 full-time employees, more than half of EPAs employees are engineers, scientists, and environmental protection specialists, other employees include legal, public affairs, financial, and information technologists. Beginning in the late 1950s and through the 1960s, Congress reacted to increasing concern about the impact that human activity could have on the environment. Senator James E. Murray introduced a bill, the Resources and Conservation Act of 1959, the 1962 publication of Silent Spring by Rachel Carson alerted the public about the detrimental effects on the environment of the indiscriminate use of pesticides. In the years following, similar bills were introduced and hearings were held to discuss the state of the environment, in the colloquium, some members of Congress expressed a continuing concern over federal agency actions affecting the environment. The National Environmental Policy Act of 1969 was modeled on RCA, President Nixon signed NEPA into law on January 1,1970. The law created the Council on Environmental Quality in the Executive Office of the President, NEPA required that a detailed statement of environmental impacts be prepared for all major federal actions significantly affecting the environment. The detailed statement would ultimately be referred to as an impact statement. On July 9,1970, Nixon proposed a reorganization that consolidated many environmental responsibilities of the federal government under one agency. After conducting hearings during that summer, the House and Senate approved the proposal, the agency’s first administrator, William Ruckelshaus, took the oath of office on December 4,1970. In May 2013, Congress renamed the EPA headquarters as the William Jefferson Clinton Federal Building, the EPA is led by an Administrator of the Environmental Protection Agency. As of 2017 Scott Pruitt is the 14th administrator, each EPA regional office is responsible within its states for implementing the Agencys programs, except those programs that have been specifically delegated to states
26.
Dicamba
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Brand names for formulations of this herbicide include Banvel, Diablo, Oracle and Vanquish. This chemical compound is an organochloride and a derivative of benzoic acid, dicamba controls annual and perennial rose weeds in grain crops and highlands, and it is used to control brush and bracken in pastures, as well as legumes and cacti. It kills broadleaf weeds before and after they sprout, in combination with a phenoxy herbicide or with other herbicides, dicamba is used in pastures, range land, and noncrop areas to control weeds. Dicamba is toxic to conifer species but is in less toxic to grasses. Dicamba functions by increasing plant growth rate, at sufficient concentrations, the plant outgrows its nutrient supplies and dies. The growth regulating properties of dicamba were first discovered by Zimmerman, soon after Jealotts Hill Experimental Station in England was evaluating dicamba in the field. Dicamba has since used for household and commercial weed control. Increasing use of dicamba has been reported with the release of dicamba resistant genetically modified plants by Monsanto, in October 2016, the EPA launched a criminal investigation into the illegal application of older, drift prone formulations of dicamba onto these new plants. Older formulations have been reported to drift after application and affect other crops not meant to be treated, new formulations of dicamba designed to be less airborne and inhibit unintended drift between fields are currently under review for EPA approval in the United States. Some weed species have developed resistance to dicamba, dicamba resistance in Bassia scoparia was discovered in 1994 and has not been explained by common modes of resistance such as absorption, translocation, or metabolism. The soil bacterium Pseudomonas maltophilia converts dicamba to 3, 6-dichlorosalicylic acid, which is adsorbed to soil much more strongly than is dicamba, little information is available on the toxicity of this breakdown intermediate. The enzymes responsible for this first breakdown step is a three-component system called dicamba O-demethylase, Monsanto recently incorporated one component of the three enzymes into the genome of soybean, cotton, and other broadleaf crop plants, making them resistant to dicamba. Monsanto has marketed their dicamba resistant crops under the brand name Xtend, dicamba came under some scrutiny due to its tendency to vaporize from treated fields and spread to neighboring crops. Incidents in which dicamba affected neighboring fields led to complaints from farmers, dicamba does not present unusual handling hazards. It is moderately toxic by ingestion and slightly toxic by inhalation or dermal exposure, in a three-generation study, dicamba did not affect the reproductive capacity of rats. When rabbits were given doses of 0,0, U. S. Environmental Protection Agency has set the NOAEL for this study at 3 /day. In dog tests, some enlargement of liver cells has occurred, dicamba is released directly to the environment by its application as an herbicide for the control of annual broadleaf weeds. It may cause damage to plants as a result of its absorption from the soil by plant roots, dicamba is mobile in most soils and significant leaching is possible
27.
Triclopyr
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Triclopyr is an organic compound in the pyridine group that is used as a systemic, foliar herbicide and fungicide. Triclopyr is used to control broadleaf weeds while leaving grasses and conifers unaffected or to control rust diseases on crops, triclopyr is effective on woody plants and is used for brush control in rights of way and defoliation of wooded areas. In the USA it is sold under the trade names Garlon and Release and it is also used for broadleaf weeds, particularly Creeping Charlie. It is sold under the trade names Turflon, Weed-B-Gon, and it is a major ingredient in Confront, which was withdrawn from most uses due to concerns about compost contamination from the other major ingredient, clopyralid. Triclopyr is formulated both as an ester and as an amine salt, the usual tradeoffs regarding effectiveness, drift, and toxicity to humans apply to these two formulations. It is chemically similar to the herbicide which it generally replaces,2,4, 5-T. Triclopyr breaks down in soil with a half-life of between 30 and 90 days, one of the byproducts of breakdown, trichloropyridinol, remains in the soil for up to a year. It remains active in decaying vegetation for about 3 months, the compound is slightly toxic to ducks and quail. It has been found non-toxic to bees and very toxic to fish
28.
Pest control
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Pest control refers to the regulation or management of a species defined as a pest, and can be perceived to be detrimental to a persons health, the ecology or the economy. A practitioner of pest control is called an exterminator, Pest control is at least as old as agriculture, as there has always been a need to keep crops free from pests. In order to maximize production, it is advantageous to protect crops from competing species of plants. Techniques such as rotation, companion planting, and the selective breeding of pest-resistant cultivars have a long history. In the UK, following concern about animal welfare, humane pest control, for instance, with the urban red fox which territorial behaviour is used against the animal, usually in conjunction with non-injurious chemical repellents. In rural areas of Britain, the use of firearms for pest control is quite common, chemical pesticides date back 4,500 years, when the Sumerians used sulfur compounds as insecticides. The Rig Veda, which is about 4,000 years old, in the 20th century, the discovery of several synthetic insecticides, such as DDT, and herbicides boosted this development. Many pests have only become a problem as a result of the actions by humans. Modifying these actions can often reduce the pest problem. In the United States, raccoons caused a nuisance by tearing open refuse sacks, many householders introduced bins with locking lids, which deterred the raccoons from visiting. House flies tend to accumulate wherever there is activity and live in close association with people all over the world especially where food or food waste is exposed. Similarly, seagulls have become pests at many seaside resorts, tourists would often feed the birds with scraps of fish and chips, and before long, the birds would rely on this food source and act aggressively towards humans. Living organisms evolve and increase their resistance to biological, chemical, physical or any form of control. Perhaps as far ago as 3000BC in Egypt, cats were being used to control pests of grain such as rodents. In 1939/40 a survey discovered that cats could keep a population of rats down to a low level. However, if the rats were cleared by trapping or poisoning, ferrets were domesticated at least by 500 AD in Europe, being used as mousers. Mongooses have been introduced into homes to control rodents and snakes, biological pest control is the control of one through the control and management of natural predators and parasites. For example, mosquitoes are often controlled by putting Bt Bacillus thuringiensis ssp. israelensis, the treatment has no known negative consequences on the remaining ecology and is safe for humans to drink
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Aniline
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Aniline is an organic compound with the formula C6H5NH2. Consisting of a group attached to an amino group, aniline is the prototypical aromatic amine. Its main use is in the manufacture of precursors to polyurethane, like most volatile amines, it possesses the odour of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds, the amine is nearly planar owing to conjugation of the lone pair with the aryl substituent. The C-N distance is correspondingly shorter, in aniline, the C-N and C-C distances are close to 1.39 Å, indicating the π-bonding between N and C. Industrial aniline production involves two steps, first, benzene is nitrated with a concentrated mixture of nitric acid and sulfuric acid at 50 to 60 °C to yield nitrobenzene. The nitrobenzene is then hydrogenated in the presence of metal catalysts, the reduction of nitrobenzene to aniline was first performed by Nikolay Zinin in 1842 using inorganic sulfide as a reductant. Aniline can alternatively be prepared from ammonia and phenol derived from the cumene process, many analogues of aniline are known where the phenyl group is further substituted. These include toluidines, xylidines, chloroanilines, aminobenzoic acids, nitroanilines and they often are prepared by nitration of the substituted aromatic compounds followed by reduction. For example, this approach is used to convert toluene into toluidines, the chemistry of aniline is rich because the compound has been cheaply available for many years. Below are some classes of its reactions, the oxidation of aniline has been heavily investigated, and can result in reactions localized at nitrogen or more commonly results in the formation of new C-N bonds. In alkaline solution, azobenzene results, whereas arsenic acid produces the violet-coloring matter violaniline, chromic acid converts it into quinone, whereas chlorates, in the presence of certain metallic salts, give aniline black. Hydrochloric acid and potassium chlorate give chloranil, potassium permanganate in neutral solution oxidizes it to nitrobenzene, in alkaline solution to azobenzene, ammonia and oxalic acid, in acid solution to aniline black. Hypochlorous acid gives 4-aminophenol and para-amino diphenylamine, oxidation with persulfate affords a variety of polyanilines compounds. These polymers exhibit rich redox and acid-base properties, like phenols, aniline derivatives are highly susceptible to electrophilic substitution reactions. Its high reactivity reflects that it is an enamine, which enhances the ability of the ring. For example, reaction of aniline with sulfuric acid at 180 °C produces sulfanilic acid, if bromine water is added to aniline, the bromine water is decolourised and a white precipitate of 2,4, 6-tribromophenylamine is formed. The largest scale industrial reaction of aniline involves its alkylation with formaldehyde, an idealized equation is shown,2 C6H5NH2 + CH2O → CH22 + H2O The resulting diamine is the precursor to 4, 4-MDI and related diisocyanates
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Acetochlor
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Acetochlor is an herbicide developed by Monsanto Company and Zeneca. It is a member of the class of known as chloroacetanilides. Its mode of action is elongase inhibition, and inhibition of geranylgeranyl pyrophosphate cyclization enzymes and it carries high risks of environmental contamination. In the United States, acetochlor was registered by the EPA as a substitute for many herbicides of known concern. The EPA imposed several restrictions and conditions on the use of acetochlor and it is approved for pre-emergence application or for pre-planting application with soil incorporation, in corn. At 5 litres / hectare It is the active ingredient in Acenit, Keystone, Guardian, Harness, Relay, Sacemid, Surpass, Top-Hand, Trophy. It is used to control weeds in corn, and is useful as a replacement for atrazine in the case of some important weeds. Acetochlor has been classified as a human carcinogen. Acetochlor, as alachlor, can cause nasal turbinate tumors via the generation of a common tissue reactive metabolite that leads to cytotoxicity, human health effects from acetochlor at low environmental doses or at biomonitored levels from low environmental exposures are unknown. In the United States, acetochlor is the third most frequently detected herbicide in natural waters, Acetochlor can accelerate metamorphosis in amphibians. It can also affect the development of fish, metolachlor U. S. Environmental Protection Agency article on Acetochlor
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