1.
Petrifaction
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Petrified wood typifies this process, but all organisms, from bacteria to vertebrates, can become petrified. Petrification takes place through a combination of two processes, permineralization and replacement. These processes create replicas of the specimen that are similar down to the microscopic level. One of the involved in petrification is permineralization. The fossils created through this process tend to contain an amount of the original material of the specimen. This process occurs when groundwater containing dissolved minerals, fills pore spaces and cavities of specimens, particularly bone, the pores of the organisms tissues are filled when these minerals precipitate out of the water. Two common types of permineralization are silicification and pyritization, silicification is the process in which organic matter becomes saturated with silica. A common source of silica is volcanic material, studies have shown that in this process, most of the original organic matter is destroyed. Silicification most often occurs in two environments-either the specimen is buried in sediments of deltas and floodplains or organisms are buried in volcanic ash, the process begins when a specimen is permeated with an aqueous silica solution. The cell walls of the specimen are progressively dissolved and silica is deposited into the empty spaces, in wood samples, as the process proceeds, cellulose and lignin, two components of wood, are degraded and replaced with silica. The specimen is transformed to stone as water is lost, pyritization is a process similar to silicification, but instead involves the deposition of iron and sulfur in the pores and cavities of an organism. Pyritization can result in both solid fossils as well as preserved soft tissues, in marine environments, pyritization occurs when organisms are buried in sediments containing a high concentration of iron sulfides. Organisms release sulfide, which reacts with dissolved iron in the surrounding water and this reaction between iron and sulfides forms pyrite. Carbonate shell material of the organism is replaced with pyrite due to a higher concentration of pyrite. Pyritization occurs to an extent in plants in clay environments. Replacement, the process involved in petrification, occurs when water containing dissolved minerals dissolves the original solid material of an organism. This can take place extremely slowly, replicating the structure of the organism. The slower the rate of the process, the better defined the structure will be
2.
Death
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Death is the cessation of all biological functions that sustain a living organism. Bodies of living organisms begin to decompose shortly after death, other concerns include fear of death, necrophobia, anxiety, sorrow, grief, emotional pain, depression, sympathy, compassion, solitude, or saudade. The potential for an afterlife is of concern for some humans, the word death comes from Old English deað, which in turn comes from Proto-Germanic *dauthuz. This comes from the Proto-Indo-European stem *dheu- meaning the Process, act, when a person has died, it is also said they have passed away, passed on, expired, or are gone, among numerous other socially accepted, religiously specific, slang, and irreverent terms. Bereft of life, the person is then a corpse, cadaver, a body, a set of remains, and when all flesh has rotted away. The terms carrion and carcass can also be used, though more often connote the remains of non-human animals. As a polite reference to a person, it has become common practice to use the participle form of decease, as in the deceased. The ashes left after a cremation are sometimes referred to by the neologism cremains, senescence refers to a scenario when a living being is able to survive all calamities, but eventually dies due to causes relating to old age. Almost all animals who survive external hazards to their biological functioning eventually die from biological aging, some organisms experience negligible senescence, even exhibiting biological immortality. These include the jellyfish Turritopsis dohrnii, the hydra, and the planarian, unnatural causes of death include suicide and homicide. From all causes, roughly 150,000 people die around the world each day, physiological death is now seen as a process, more than an event, conditions once considered indicative of death are now reversible. Where in the process a dividing line is drawn between life and death depends on factors beyond the presence or absence of vital signs, in general, clinical death is neither necessary nor sufficient for a determination of legal death. A patient with working heart and lungs determined to be dead can be pronounced legally dead without clinical death occurring. As scientific knowledge and medicine advance, formulating a precise definition of death becomes more difficult. The concept of death is a key to understanding of the phenomenon. There are many approaches to the concept. For example, brain death, as practiced in medical science, One of the challenges in defining death is in distinguishing it from life. As a point in time, death would seem to refer to the moment at which life ends, determining when death has occurred requires drawing precise conceptual boundaries between life and death
3.
Livor mortis
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Livor mortis, postmortem lividity, hypostasis or suggillation, is the fourth stage and one of the signs of death. It is a settling of the blood in the portion of the body post mortem. When the heart stops functioning and is no longer agitating the blood, livor mortis starts in 20–30 minutes, but is usually not observable by the human eye until two hours after death. The size of the increases in the next 3–6 hours. The blood pools into the tissues of the body. The intensity of the color depends upon the amount of reduced hemoglobin in the blood, the discoloration does not occur in the areas of the body that are in contact with the ground or another object, in which capillaries are compressed. Coroners can use the presence or absence of livor mortis as a means of determining a time of death. It can also be used by investigators to determine whether or not a body has been moved. For instance, if the body is lying prone, but the pooling is present on the deceaseds back. Among coroners and other investigators, such as homicide and forensic detectives, livor mortis is not considered a way to measure time of death. Livor mortis, along with algor mortis, rigor mortis, and practices such as forensic entomology are frequently combined by investigators to more accurately pinpoint the estimated time of death
4.
Decomposition
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Decomposition is the process by which organic substances are broken down into simpler matter. The process is a part of nutrient cycle and is essential for recycling the matter that occupies physical space in the biosphere. Bodies of living organisms begin to decompose shortly after death, animals, such as worms, also help decompose the organic materials. Organisms that do this are known as decomposers, although no two organisms decompose in the same way, they all undergo the same sequential stages of decomposition. The science which studies decomposition is referred to as taphonomy from the Greek word τάφος taphos. One can differentiate abiotic from biotic decomposition, the former means degradation of a substance by chemical or physical processes, e. g. hydrolysis. The latter means the metabolic breakdown of materials into simpler components by living organisms and these processes release gases, such as cadaverine and putrescine, that are the chief source of the unmistakably putrid odor of decaying animal tissue. Prime decomposers are bacteria or fungi, though larger scavengers also play an important role in decomposition if the body is accessible to insects, mites and other animals. The most important arthropods that are involved in the process include carrion beetles, mites, the most important non-insect animals that are typically involved in the process include mammal and bird scavengers, such as coyotes, dogs, wolves, foxes, rats, crows and vultures. Some of these scavengers also remove and scatter bones, which they ingest at a later time, aquatic and marine environments have break-down agents that include bacteria, fish, crustaceans, Diptera larvae and other carrion scavengers. Five general stages are used to describe the process of decomposition in vertebrate animals, fresh, bloat, active and advanced decay, the general stages of decomposition are coupled with two stages of chemical decomposition, autolysis and putrefaction. These two stages contribute to the process of decomposition, which breaks down the main components of the body. The fresh stage begins immediately after the heart stops beating, from the moment of death, the body begins cooling or warming to match the temperature of the ambient environment, during a stage called algor mortis. Shortly after death, within three to six hours, the tissues become rigid and incapable of relaxing, during a stage called rigor mortis. Once the heart stops, the blood can no longer supply oxygen or remove carbon dioxide from the tissues and this process is known as autolysis. Visible changes caused by decomposition are limited during the fresh stage and these multiply, consuming the bodys carbohydrates, lipids, and proteins, to produce a variety of substances including propionic acid, lactic acid, methane, hydrogen sulfide, and ammonia. The process of microbial proliferation within a body is referred to as putrefaction and leads to the stage of decomposition. Blowflies and flesh flies are the first carrion insects to arrive, the bloat stage provides the first clear visual sign that microbial proliferation is underway
5.
Skeletonization
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Skeletonization refers to the final stage of death, during which the last vestiges of the soft tissues of a corpse or carcass have decayed or dried to the point that the skeleton is exposed. By the end of the process, all soft tissue will have been eliminated. In tropical climates, skeletonization can occur in weeks, while in areas, skeletonization may take years or may never occur. Natural embalming processes in peat bogs or salt deserts can delay the process indefinitely, the rate of skeletonization and the present condition of a corpse or carcass can be used to determine the time of death. In neutral-pH soil or sand, the skeleton can persist for hundreds of years before it finally disintegrates, alternately, especially in very fine, dry, salty, anoxic, or mildly alkaline soils, bones may undergo fossilization, converting into minerals that may persist indefinitely. The organic components, as opposed to the salts in bone
6.
Fossil
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Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record. The study of fossils across geological time, how they were formed, such a preserved specimen is called a fossil if it is older than some minimum age, most often the arbitrary date of 10,000 years. The observation that fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of dating techniques in the early 20th century allowed geologists to determine the numerical or absolute age of the various strata. Like extant organisms, fossils vary in size from microscopic, even single bacterial cells one micrometer in diameter, to gigantic, such as dinosaurs, Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces. These types of fossil are called trace fossils, as opposed to body fossils, finally, past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals, these are known as chemofossils or biosignatures. The process of fossilization varies according to type and external conditions. Permineralization is a process of fossilization that occurs when an organism is buried, the empty spaces within an organism become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces and this process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils, for permineralization to occur, the organism must become covered by sediment soon after death or soon after the initial decay process. The degree to which the remains are decayed when covered determines the later details of the fossil, some fossils consist only of skeletal remains or teeth, other fossils contain traces of skin, feathers or even soft tissues. This is a form of diagenesis, in some cases the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold, if this hole is later filled with other minerals, it is a cast. An endocast or internal mold is formed when sediments or minerals fill the cavity of an organism. This is a form of cast and mold formation. If the chemistry is right, the organism can act as a nucleus for the precipitation of minerals such as siderite, if this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization, replacement occurs when the shell, bone or other tissue is replaced with another mineral
7.
Protein
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Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, a linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide, short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds, the sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the code specifies 20 standard amino acids, however. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors, proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes. Once formed, proteins only exist for a period of time and are then degraded and recycled by the cells machinery through the process of protein turnover. A proteins lifespan is measured in terms of its half-life and covers a wide range and they can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded proteins are degraded more rapidly due to being targeted for destruction or due to being unstable. Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms, many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized, digestion breaks the proteins down for use in the metabolism. Methods commonly used to study structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance. Most proteins consist of linear polymers built from series of up to 20 different L-α-amino acids, all proteinogenic amino acids possess common structural features, including an α-carbon to which an amino group, a carboxyl group, and a variable side chain are bonded. Only proline differs from this structure as it contains an unusual ring to the N-end amine group. The amino acids in a chain are linked by peptide bonds. Once linked in the chain, an individual amino acid is called a residue, and the linked series of carbon, nitrogen. The peptide bond has two forms that contribute some double-bond character and inhibit rotation around its axis, so that the alpha carbons are roughly coplanar
8.
Phenol
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Phenol, also known as carbolic acid, is an aromatic organic compound with the molecular formula C6H5OH. It is a crystalline solid that is volatile. The molecule consists of a phenyl group bonded to a hydroxyl group and it is mildly acidic and requires careful handling due to its propensity to cause chemical burns. Phenol was first extracted from tar, but today is produced on a large scale from petroleum. It is an important industrial commodity as a precursor to many materials and it is primarily used to synthesize plastics and related materials. Phenol and its derivatives are essential for production of polycarbonates, epoxies, Bakelite, nylon, detergents, herbicides such as phenoxy herbicides. Phenol is appreciably soluble in water, with about 84.2 g dissolving in 1000 mL, homogeneous mixtures of phenol and water at phenol to water mass ratios of ~2.6 and higher are possible. The sodium salt of phenol, sodium phenoxide, is far more water-soluble and it reacts completely with aqueous NaOH to lose H+, whereas most alcohols react only partially. One explanation for the increased acidity over alcohols is resonance stabilization of the anion by the aromatic ring. In this way, the charge on oxygen is delocalized on to the ortho. In another explanation, increased acidity is the result of orbital overlap between the lone pairs and the aromatic system. The pKa of the enol of acetone is 10.9, the acidities of phenol and acetone enol diverge in the gas phase owing to the effects of solvation. About 1⁄3 of the acidity of phenol is attributable to inductive effects. Phenolate esters are more stable toward hydrolysis than acid anhydrides and acyl halides but are sufficiently reactive under mild conditions to facilitate the formation of amide bonds, Phenol exhibits keto-enol tautomerism with its unstable keto tautomer cyclohexadienone, but only a tiny fraction of phenol exists as the keto form. The equilibrium constant for enolisation is approximately 10−13, meaning only one in every ten trillion molecules is in the keto form at any moment. The small amount of stabilisation gained by exchanging a C=C bond for a C=O bond is more than offset by the large destabilisation resulting from the loss of aromaticity, Phenol therefore exists essentially entirely in the enol form. Phenoxides are enolates stabilised by aromaticity, under normal circumstances, phenoxide is more reactive at the oxygen position, but the oxygen position is a hard nucleophile whereas the alpha-carbon positions tend to be soft. Phenol is highly reactive toward electrophilic aromatic substitution as the oxygen atoms pi electrons donate electron density into the ring, by this general approach, many groups can be appended to the ring, via halogenation, acylation, sulfonation, and other processes
9.
Arsenic
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Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in minerals, usually in combination with sulfur and metals. It has various allotropes, but only the form is important to industry. The primary use of arsenic is in alloys of lead. Arsenic is a common dopant in semiconductor electronic devices. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, a few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic are a dietary element in rats, hamsters, goats, chickens. However, arsenic poisoning occurs in multicellular life if quantities are larger than needed, Arsenic contamination of groundwater is a problem that affects millions of people across the world. The three most common allotropes are metallic gray, yellow, and black arsenic, with gray being the most common. Gray arsenic adopts a structure consisting of many interlocked, ruffled, six-membered rings. Because of weak bonding between the layers, gray arsenic is brittle and has a relatively low Mohs hardness of 3.5. Nearest and next-nearest neighbors form an octahedral complex, with the three atoms in the same double-layer being slightly closer than the three atoms in the next. This relatively close packing leads to a density of 5.73 g/cm3. Gray arsenic is a semimetal, but becomes a semiconductor with a bandgap of 1. 2–1.4 eV if amorphized, gray arsenic is also the most stable form. Yellow arsenic is soft and waxy, and somewhat similar to tetraphosphorus, both have four atoms arranged in a tetrahedral structure in which each atom is bound to each of the other three atoms by a single bond. This unstable allotrope, being molecular, is the most volatile, least dense, solid yellow arsenic is produced by rapid cooling of arsenic vapor, As 4. It is rapidly transformed into gray arsenic by light, the yellow form has a density of 1.97 g/cm3. Black arsenic is similar in structure to red phosphorus, black arsenic can also be formed by cooling vapor at around 100–220 °C
10.
Strychnine
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Strychnine is a highly toxic, colorless, bitter, crystalline alkaloid used as a pesticide, particularly for killing small vertebrates such as birds and rodents. Strychnine, when inhaled, swallowed, or absorbed through the eyes or mouth, causes poisoning which results in muscular convulsions, while it has no known medicinal effects, in the past the convulsant effect was believed to be beneficial in small doses. The most common source is from the seeds of the Strychnos nux-vomica tree, Strychnine was the first alkaloid to be identified in plants of the genus Strychnos, family Loganiaceae. Strychnos, named by Carl Linnaeus in 1753, is a genus of trees, the genus contains 196 various species and is distributed throughout the warm regions of Asia, America, and Africa. The seeds and bark of plants in this genus contain strychnine. The inhabitants of these countries had historical knowledge of the species Strychnos nux-vomica, Strychnos nux-vomica is a tree native to the tropical forests on the Malabar Coast in Southern India, Sri Lanka and Indonesia, which attains a height of about 12 metres. The tree has a crooked, short, thick trunk and the wood is close grained, the fruit has an orange color and is about the size of a large apple with a hard rind and contains five seeds, which are covered with a soft wool-like substance. The ripe seeds look like flattened disks, which are very hard and these seeds are the chief commercial source of strychnine and were first imported to and marketed in Europe as a poison to kill rodents and small predators. Strychnos ignatii is a climbing shrub of the Philippines. The fruit of the plant, known as Saint Ignatius bean, the seeds contain more strychnine than other commercial alkaloids. The properties of S. nux-vomica and S. ignatii are substantially those of the alkaloid strychnine, Strychnine was first discovered by French chemists Joseph Bienaimé Caventou and Pierre-Joseph Pelletier in 1818 in the Saint-Ignatius bean. In some Strychnos plants a 9, 10-dimethoxy derivative of strychnine, brucine is not as poisonous as strychnine. Historic records indicate that preparations containing strychnine had been used to dogs, cats. The structure of strychnine was first determined in 1946 by Sir Robert Robinson and this is one of the most famous syntheses in the history of organic chemistry. Both chemists won the Nobel prize, Strychnine was popularly used as an athletic performance enhancer and recreational stimulant in the late 19th century and early 20th century, due to its convulsant effects. It was thought to be similar to coffee and its effects are well-described in H. G. Wells novella The Invisible Man, the title character states, Strychnine is a grand tonic. to take the flabbiness out of a man. The protagonist replies, Its the devil and its the palaeolithic in a bottle. In high doses, strychnine is very toxic to humans and many other animals, S. Strychnine poisoning in animals usually occurs from ingestion of baits designed for use against gophers, moles, and coyotes
11.
Zinc chloride
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Zinc chloride is the name of chemical compounds with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, ZnCl2 itself is hygroscopic and even deliquescent. Samples should therefore be protected from sources of moisture, including the water present in ambient air. Zinc chloride finds wide application in textile processing, metallurgical fluxes, no mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn58Cl2·H2O. Four crystalline forms of ZnCl2 are known, α, β, γ, and δ, here, a, b, and c are lattice constants, Z is the number of structure units per unit cell and ρ is the density calculated from the structure parameters. Rapid cooling of molten ZnCl2 gives a glass, the covalent character of the anhydrous material is indicated by its relatively low melting point of 275 °C. Further evidence for covalency is provided by the solubility of the dichloride in ethereal solvents where it forms adducts with the formula ZnCl2L2. In the gas phase, ZnCl2 molecules are linear with a length of 205 pm. Molten ZnCl2 has a viscosity at its melting point and a comparatively low electrical conductivity that increases markedly with temperature. A Raman scattering study of the melt indicated the presence of polymeric structures, five hydrates of zinc chloride are known, ZnCl2n where n =1,1.5,2.5,3 and 4. The tetrahydrate ZnCl24 crystallizes from solutions of zinc chloride. Anhydrous ZnCl2 can be prepared from zinc and hydrogen chloride, Zn +2 HCl → ZnCl2 + H2 Hydrated forms and aqueous solutions may be readily prepared similarly by treating Zn metal with hydrochloric acid. Commercial samples of zinc chloride typically contain water and products from hydrolysis as impurities, such samples may be purified by recrystallization from hot dioxane. Anhydrous samples can be purified by sublimation in a stream of hydrogen chloride gas, finally, the simplest method relies on treating the zinc chloride with thionyl chloride. Molten anhydrous ZnCl2 at 500–700 °C dissolves zinc metal, and, on cooling of the melt, a yellow diamagnetic glass is formed. A number of containing the tetrachlorozincate anion, ZnCl2−4, are known. Caultons reagent, V2Cl36Zn2Cl6 is an example of a salt containing Zn2Cl2−6, the compound Cs3ZnCl5 contains tetrahedral ZnCl2−4 and Cl− anions. No compounds containing the ZnCl4−6 ion have been characterized, whilst zinc chloride is very soluble in water, solutions cannot be considered to contain simply solvated Zn2+ ions and Cl− ions, ZnClxH2O species are also present
12.
Body farm
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A body farm is a research facility where decomposition can be studied in a variety of settings. They were invented by an anthropologist named William Bass in 1972, previous to this, in the 1970s, pig remains were used to study decomposition processes. Body farm research is of particular interest in anthropology and related disciplines. By placing the bodies outside to face the elements, researchers are able to get an understanding of the decomposition process. Six such facilities exist in the United States, with the facility operated by Texas State University at Freeman Ranch being the largest at 26-acres in area. Dr Richard Jantz, a director of the forensic anthropology center, advises to observe where human look, breathe, all these aspects support by the training of medical examiners, death scene investigators and law enforcement investigators. It was first started in late 1981 by anthropologist Dr. William M. Bass as a facility for the study of the decomposition of human remains, since no facilities existed that specifically studied decomposition, in 1972 he opened the departments first body farm. It consists of a 2. 5-acre wooded plot, surrounded by a wire fence. At any one time there will be a number of bodies placed in different settings throughout the facility, the bodies are exposed in a number of ways in order to provide insights into decomposition under varying conditions. Observations and records of the process are kept, including the sequence and speed of decomposition. The human decomposition stages that are studied begin with the stage, then the bloat stage, then decay. Over 100 bodies are donated to the facility every year, some individuals pre-register before their death, and others are donated by their families or by a medical examiner. 60% of donations are made by members of individuals who were not pre-registered with the facility. Over 1300 people have chosen to pre-register themselves, perhaps the most famous person to donate his body for study was the anthropologist Grover Krantz, as described by his colleague David Hunt at the Smithsonian. The University of Tennessee Body Farm is also used in the training of law enforcement officers in scene-of-crime skills, the facility is known as the Forensic Osteology Research Station or more commonly as the FOREST. It was opened in 2006 and is run by WCUs Forensic Anthropology program on a plot on the rural mountain campus. The facility studies decomposition in the western North Carolina mountain habitat and has used for cadaver dog training. The forensic research facility is fully operational and is part of the Forensic Anthropology Center at Texas State, the development of this facility has been possible through the efforts of Dr. Jerry Melbye, D-ABFA
13.
Thermodynamics
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Thermodynamics is a branch of science concerned with heat and temperature and their relation to energy and work. The behavior of these quantities is governed by the four laws of thermodynamics, the laws of thermodynamics are explained in terms of microscopic constituents by statistical mechanics. Thermodynamics applies to a variety of topics in science and engineering, especially physical chemistry, chemical engineering. The initial application of thermodynamics to mechanical heat engines was extended early on to the study of chemical compounds, Chemical thermodynamics studies the nature of the role of entropy in the process of chemical reactions and has provided the bulk of expansion and knowledge of the field. Other formulations of thermodynamics emerged in the following decades, statistical thermodynamics, or statistical mechanics, concerned itself with statistical predictions of the collective motion of particles from their microscopic behavior. In 1909, Constantin Carathéodory presented a mathematical approach to the field in his axiomatic formulation of thermodynamics. A description of any thermodynamic system employs the four laws of thermodynamics that form an axiomatic basis, the first law specifies that energy can be exchanged between physical systems as heat and work. In thermodynamics, interactions between large ensembles of objects are studied and categorized, central to this are the concepts of the thermodynamic system and its surroundings. A system is composed of particles, whose average motions define its properties, properties can be combined to express internal energy and thermodynamic potentials, which are useful for determining conditions for equilibrium and spontaneous processes. With these tools, thermodynamics can be used to describe how systems respond to changes in their environment and this can be applied to a wide variety of topics in science and engineering, such as engines, phase transitions, chemical reactions, transport phenomena, and even black holes. This article is focused mainly on classical thermodynamics which primarily studies systems in thermodynamic equilibrium, non-equilibrium thermodynamics is often treated as an extension of the classical treatment, but statistical mechanics has brought many advances to that field. Guericke was driven to make a vacuum in order to disprove Aristotles long-held supposition that nature abhors a vacuum. Shortly after Guericke, the English physicist and chemist Robert Boyle had learned of Guerickes designs and, in 1656, in coordination with English scientist Robert Hooke, using this pump, Boyle and Hooke noticed a correlation between pressure, temperature, and volume. In time, Boyles Law was formulated, which states that pressure, later designs implemented a steam release valve that kept the machine from exploding. By watching the valve rhythmically move up and down, Papin conceived of the idea of a piston and he did not, however, follow through with his design. Nevertheless, in 1697, based on Papins designs, engineer Thomas Savery built the first engine, although these early engines were crude and inefficient, they attracted the attention of the leading scientists of the time. Black and Watt performed experiments together, but it was Watt who conceived the idea of the condenser which resulted in a large increase in steam engine efficiency. Drawing on all the work led Sadi Carnot, the father of thermodynamics, to publish Reflections on the Motive Power of Fire
14.
Amino acid
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Amino acids are organic compounds containing amine and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an acid are carbon, hydrogen, oxygen. About 500 amino acids are known and can be classified in many ways, in the form of proteins, amino acids comprise the second-largest component of human muscles, cells and other tissues. Outside proteins, amino acids perform critical roles in such as neurotransmitter transport. In biochemistry, amino acids having both the amine and the acid groups attached to the first carbon atom have particular importance. They are known as 2-, alpha-, or α-amino acids and they include the 22 proteinogenic amino acids, which combine into peptide chains to form the building-blocks of a vast array of proteins. These are all L-stereoisomers, although a few D-amino acids occur in bacterial envelopes, as a neuromodulator, twenty of the proteinogenic amino acids are encoded directly by triplet codons in the genetic code and are known as standard amino acids. The other two are selenocysteine, and pyrrolysine, pyrrolysine and selenocysteine are encoded via variant codons, for example, selenocysteine is encoded by stop codon and SECIS element. N-formylmethionine is generally considered as a form of methionine rather than as a separate proteinogenic amino acid, codon–tRNA combinations not found in nature can also be used to expand the genetic code and create novel proteins known as alloproteins incorporating non-proteinogenic amino acids. Many important proteinogenic and non-proteinogenic amino acids also play critical roles within the body. Nine proteinogenic amino acids are called essential for humans because they cannot be created from other compounds by the human body, others may be conditionally essential for certain ages or medical conditions. Essential amino acids may also differ between species, because of their biological significance, amino acids are important in nutrition and are commonly used in nutritional supplements, fertilizers, and food technology. Industrial uses include the production of drugs, biodegradable plastics, the first few amino acids were discovered in the early 19th century. In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound in asparagus that was subsequently named asparagine, cystine was discovered in 1810, although its monomer, cysteine, remained undiscovered until 1884. Glycine and leucine were discovered in 1820, usage of the term amino acid in the English language is from 1898. Proteins were found to yield amino acids after enzymatic digestion or acid hydrolysis, in the structure shown at the top of the page, R represents a side chain specific to each amino acid. The carbon atom next to the group is called the α–carbon. Amino acids containing an amino group bonded directly to the alpha carbon are referred to as amino acids
15.
Anaerobic organism
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An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if oxygen is present, an anaerobic organism may be unicellular or multicellular. Van Leeuwenhoek sealed one of the tubes by using a flame. In 1913 Martinus Beijerinck repeated Van Leeuwenhoeks experiment and identified Clostridium butyricum as a prominent anaerobic bacterium in the sealed pepper infusion tube liquid. That Leeuwenhoek, one hundred years before the discovery of oxygen, for practical purposes, there are three categories of anaerobe, Obligate anaerobes, which are harmed by the presence of oxygen. Aerotolerant organisms, which use oxygen for growth, but tolerate its presence. Facultative anaerobes, which can grow without oxygen but use oxygen if it is present, some obligate anaerobes use fermentation, while others use anaerobic respiration. In the presence of oxygen, facultative anaerobes use aerobic respiration, without oxygen, some of them ferment, there are many anaerobic fermentative reactions. This is only 5% of the energy per molecule that the typical aerobic reaction generates. Since normal microbial culturing occurs in air, which is an aerobic environment. Hydrogen then reacts with oxygen gas on a palladium catalyst to more water. The issue with the Gaspak method is that a reaction can take place where the bacteria may die. The thioglycollate supplies a medium mimicking that of a dicot, thus providing not only an anaerobic environment, complex multicellular life that does not need oxygen is said to be rare, however there are examples of such organisms. Some organisms metabolise primarily using glycogen, for example the Nereid s and some polychaetes, or the juvenile Trichinella spiralis parasites. )
16.
Gastrointestinal tract
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Gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines. A tract is a collection of related anatomic structures or a series of connected body organs, the mouth, oesophagus, stomach, and intestines are part of the human alimentary canal. All bilaterians have a gastrointestinal tract, also called a gut or an alimentary canal and this is a tube that transfers food to the organs of digestion. In large bilaterians, the gastrointestinal tract generally also has an exit, some small bilaterians have no anus and dispose of solid wastes by other means. The gastrointestinal tract contains thousands of different bacteria in their gut flora, the human gastrointestinal tract consists of the esophagus, stomach, and intestines, and is divided into the upper and lower gastrointestinal tracts. In contrast, the digestive system comprises the gastrointestinal tract plus the accessory organs of digestion. The tract may also be divided into foregut, midgut, and hindgut, the whole human GI tract is about nine metres long at autopsy. The GI tract releases hormones from enzymes to help regulate the digestive process, the structure and function can be described both as gross anatomy and as microscopic anatomy or histology. The tract itself is divided into upper and lower tracts, the upper gastrointestinal tract consists of the buccal cavity, pharynx, esophagus, stomach, and duodenum. The exact demarcation between the upper and lower tracts is the muscle of the duodenum. Upon dissection, the duodenum may appear to be an organ, but it is divided into four segments based upon function, location. The four segments of the duodenum are as follows, bulb, descending, horizontal, the suspensory muscle attaches the superior border of the ascending duodenum to the diaphragm. The suspensory muscle is an important anatomical landmark which shows the division between the duodenum and the jejunum, the first and second parts of the small intestine. This is a muscle which is derived from the embryonic mesoderm. The lower gastrointestinal tract includes most of the intestine and all of the large intestine. In humans, the intestine is further subdivided into the duodenum, jejunum and ileum while the large intestine is subdivided into the cecum, colon, rectum. The small intestine begins at the duodenum, which receives food from the stomach and it is a tubular structure, usually between 6 and 7 m long. The area of the human, adult small intestinal mucosa is about 30 m2 and its main function is to absorb the products of digestion into the bloodstream
17.
Oba Chandler
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Autopsies showed the victims had been thrown into the water while still alive, with ropes around their necks with a concrete block tied at the other end of the rope. The case became high-profile in 1992 when local police posted enlargements of samples of a then unknown suspects handwriting, found on a pamphlet in the victims car, Chandler was identified as the killer when his neighbor recognized the handwriting. This was the first such use of billboards by law enforcement in the U. S. billboards became useful tools in later searches for missing people, prior to his arrest, Chandler worked as an unlicensed aluminum-siding contractor. Police originally theorized that two men were involved in the murders, but this was discounted once Chandler was arrested, Chandler was executed on November 15,2011. He wrote a last statement to prison officials said, You are killing a innocent man today. The statement was read at a news conference. In February 2014, DNA evidence identified Chandler as the murderer of Ivelisse Berrios-Beguerisse, Chandler was the fourth of five children born to Oba Chandler Sr. and Margaret Johnson, and was raised in Cincinnati, Ohio. When he was 10 years old in June 1957, his father hanged himself in the basement of the familys apartment, Chandler reportedly jumped into his fathers open grave at the funeral as the gravediggers were covering the coffin with dirt. Chandler fathered eight children, reportedly by seven women, his youngest child was born in February 1989, between May and September 1991—concurrent with the police investigation of the Rogers family triple murder—Chandler was an informant for the U. S. Customs Bureaus Tampa office. When Chandler was 14, he began stealing cars and was arrested 20 times as a juvenile, as an adult, he was charged with a variety of crimes, including possession of counterfeit money, loitering and prowling, burglary, kidnapping, and armed robbery. He was also accused of masturbating while peering inside a womans window, in one incident, Chandler and an accomplice broke into a Florida couples home, held them at gunpoint, and robbed them. On May 26,1989, Joan Jo Rogers,36, and her daughters—Michelle,17 and they had never before left their home state. Authorities believe that the women became lost on June 1, during the drive from Orlando to Willshire. While looking for their hotel they encountered Chandler, who gave them directions, the Rogers women had left Orlando around 9,00 a. m. and checked into the Days Inn on Route 60 at 12,30 p. m. They were last seen alive at the hotel restaurant around 7,30 p. m. It is believed they boarded Chandlers boat by the dock on the Courtney Campbell Causeway between 8,30 p. m. and 9,00 p. m. and that they were dead by 3 a. m. Chandler may have used the fact that he was born in Ohio to lure them into feeling a connection to him, Chandler knew the women were not from Florida because he saw the Ohio license plates on their car. The womens bodies were floating in Tampa Bay on June 4,1989
18.
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
19.
Functional group
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In organic chemistry, functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of, however, its relative reactivity can be modified by other functional groups nearby. The atoms of functional groups are linked to other and to the rest of the molecule by covalent bonds. Any subgroup of atoms of a compound also may be called a radical, and if a covalent bond is broken homolytically, Functional groups can also be charged, e. g. in carboxylate salts, which turns the molecule into a polyatomic ion or a complex ion. Complexation and solvation is also caused by interactions of functional groups. In the common rule of thumb like dissolves like, it is the shared or mutually well-interacting functional groups give rise to solubility. For example, sugar dissolves in water because both share the functional group and hydroxyls interact strongly with each other. Combining the names of groups with the names of the parent alkanes generates what is termed a systematic nomenclature for naming organic compounds. In traditional nomenclature, the first carbon atom after the carbon that attaches to the group is called the alpha carbon, the second, beta carbon. IUPAC conventions call for numeric labeling of the position, e. g. 4-aminobutanoic acid, in traditional names various qualifiers are used to label isomers, for example isopropanol is an isomer is n-propanol. The following is a list of functional groups. In the formulas, the symbols R and R usually denote an attached hydrogen, or a side chain of any length. Functional groups, called hydrocarbyl, that only carbon and hydrogen. Each one differs in type of reactivity, there are also a large number of branched or ring alkanes that have specific names, e. g. tert-butyl, bornyl, cyclohexyl, etc. Hydrocarbons may form charged structures, positively charged carbocations or negative carbanions, examples are tropylium and triphenylmethyl cations and the cyclopentadienyl anion. Haloalkanes are a class of molecule that is defined by a carbon–halogen bond and this bond can be relatively weak or quite stable. In general, with the exception of fluorinated compounds, haloalkanes readily undergo nucleophilic substitution reactions or elimination reactions, the substitution on the carbon, the acidity of an adjacent proton, the solvent conditions, etc. all can influence the outcome of the reactivity. Compounds that contain nitrogen in this category may contain C-O bonds, compounds that contain sulfur exhibit unique chemistry due to their ability to form more bonds than oxygen, their lighter analogue on the periodic table
20.
Amine
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In organic chemistry, amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group, important amines include amino acids, biogenic amines, trimethylamine, and aniline, see Category, Amines for a list of amines. Inorganic derivatives of ammonia are also called amines, such as chloramine, see Category, compounds with a nitrogen atom attached to a carbonyl group, thus having the structure R–CO–NR′R″, are called amides and have different chemical properties from amines. An aliphatic amine has no aromatic ring attached directly to the nitrogen atom, aromatic amines have the nitrogen atom connected to an aromatic ring as in the various anilines. The aromatic ring decreases the alkalinity of the amine, depending on its substituents, the presence of an amine group strongly increases the reactivity of the aromatic ring, due to an electron-donating effect. Amines are organized into four subcategories, Primary amines — Primary amines arise when one of three atoms in ammonia is replaced by an alkyl or aromatic. Important primary alkyl amines include, methylamine, most amino acids, Secondary amines — Secondary amines have two organic substituents bound to the nitrogen together with one hydrogen. Important representatives include dimethylamine, while an example of an aromatic amine would be diphenylamine, tertiary amines — In tertiary amines, nitrogen has three organic substituents. Examples include trimethylamine, which has a fishy smell. Cyclic amines — Cyclic amines are either secondary or tertiary amines, examples of cyclic amines include the 3-membered ring aziridine and the six-membered ring piperidine. N-methylpiperidine and N-phenylpiperidine are examples of tertiary amines. It is also possible to have four organic substituents on the nitrogen and these species are not amines but are quaternary ammonium cations and have a charged nitrogen center. Quaternary ammonium salts exist with many kinds of anions, Amines are named in several ways. Typically, the compound is given the prefix amino- or the suffix, the prefix N- shows substitution on the nitrogen atom. An organic compound with multiple amino groups is called a diamine, triamine, tetraamine, systematic names for some common amines, Hydrogen bonding significantly influences the properties of primary and secondary amines. Thus the melting point and boiling point of amines is higher than those of the corresponding phosphines, for example, methyl and ethyl amines are gases under standard conditions, whereas the corresponding methyl and ethyl alcohols are liquids. Amines possess a characteristic smell, liquid amines have a distinctive fishy smell. The nitrogen atom features a lone pair that can bind H+ to form an ammonium ion R3NH+
21.
Lysine
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Lysine, encoded by the codons AAA and AAG, is an α-amino acid that is used in the biosynthesis of proteins. It contains a group, an α-carboxylic acid group. It is essential in humans, meaning the body cannot synthesize it, lysine is a base, as are arginine and histidine. The ε-amino group often participates in hydrogen bonding and as a base in catalysis. The ε-amino group is attached to the carbon from the α-carbon. O-Glycosylation of hydroxylysine residues in the endoplasmic reticulum or Golgi apparatus is used to mark certain proteins for secretion from the cell, deficiencies may cause blindness, as well as many other problems due to its ubiquitous presence in proteins. As an essential amino acid, lysine is not synthesized in animals, in plants and most bacteria, it is synthesized from aspartic acid, L-aspartate is first converted to L-aspartyl-4-phosphate by aspartokinase. ATP is needed as a source for this step. β-Aspartate semialdehyde dehydrogenase converts this into β-aspartyl-4-semialdehyde, energy from NADPH is used in this conversion. 4-hydroxy-tetrahydrodipicolinate synthase adds a pyruvate group to the β-aspartyl-4-semialdehyde, and a molecule is removed. This causes cyclization and gives rise to -4-hydroxy-2,3,4 and this product is reduced to 2,3,4, 5-tetrahydrodipicolinate by 4-hydroxy-tetrahydrodipicolinate reductase. This reaction consumes an NADPH molecule and releases a water molecule. Tetrahydrodipicolinate N-acetyltransferase opens this ring and gives rise to N-succinyl-L-2-amino-6-oxoheptanedionate, two water molecules and one acyl-CoA enzyme are used in this reaction. This reaction is catalyzed by the enzyme succinyl diaminopimelate aminotransferase, a glutamic acid molecule is used in this reaction and an oxoacid is produced as a byproduct. N-succinyl-LL-2, 6-diaminoheptanedionate is converted into LL-2, 6-diaminoheptanedionate by succinyl diaminopimelate desuccinylase, a water molecule is consumed in this reaction and a succinate is produced a byproduct. LL-2, 6-diaminoheptanedionate is converted by diaminopimelate epimerase into meso-2, 6-diamino-heptanedionate, finally, meso-2, 6-diamino-heptanedionate is converted into L-lysine by diaminopimelate decarboxylase. It is worth noting, however, that in fungi, euglenoids, lysine is metabolised in mammals to give acetyl-CoA, via an initial transamination with α-ketoglutarate. The bacterial degradation of lysine yields cadaverine by decarboxylation, allysine is a derivative of lysine, used in the production of elastin and collagen
22.
Ethanol
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Ethanol, also called alcohol, ethyl alcohol, and drinking alcohol, is the principal type of alcohol found in alcoholic beverages. It is a volatile, flammable, colorless liquid with a characteristic odor. Its chemical formula is C 2H 6O, which can be written also as CH 3-CH 2-OH or C 2H 5-OH, ethanol is mostly produced by the fermentation of sugars by yeasts, or by petrochemical processes. It is a psychoactive drug, causing a characteristic intoxication. It is widely used as a solvent, as fuel, and as a feedstock for synthesis of other chemicals, the eth- prefix and the qualifier ethyl in ethyl alcohol originally come from the name ethyl assigned in 1834 to the group C 2H 5- by Justus Liebig. He coined the word from the German name Aether of the compound C 2H 5-O-C 2H5, according to the Oxford English Dictionary, Ethyl is a contraction of the Ancient Greek αἰθήρ and the Greek word ύλη. The name ethanol was coined as a result of a resolution that was adopted at the International Conference on Chemical Nomenclature that was held in April 1892 in Geneva, Switzerland. The term alcohol now refers to a class of substances in chemistry nomenclature. The Oxford English Dictionary claims that it is a loan from Arabic al-kuḥl, a powdered ore of antimony used since aniquity as a cosmetic. The use of alcohol for ethanol is modern, first recorded 1753, the systematic use in chemistry dates to 1850. Ethanol is used in medical wipes and most common antibacterial hand sanitizer gels as an antiseptic, ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses. However, ethanol is ineffective against bacterial spores, ethanol may be administered as an antidote to methanol and ethylene glycol poisoning. Ethanol, often in high concentrations, is used to dissolve many water-insoluble medications, as a central nervous system depressant, ethanol is one of the most commonly consumed psychoactive drugs. The amount of ethanol in the body is typically quantified by blood alcohol content, small doses of ethanol, in general, produce euphoria and relaxation, people experiencing these symptoms tend to become talkative and less inhibited, and may exhibit poor judgment. Ethanol is commonly consumed as a drug, especially while socializing. The largest single use of ethanol is as a fuel and fuel additive. Brazil in particular relies heavily upon the use of ethanol as an engine fuel, gasoline sold in Brazil contains at least 25% anhydrous ethanol. Hydrous ethanol can be used as fuel in more than 90% of new gasoline fueled cars sold in the country, Brazilian ethanol is produced from sugar cane and noted for high carbon sequestration
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Blood Alcohol Concentration
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Blood Alcohol Content is the legal name for BAC but Blood Alcohol Concentration is sometimes used for simpler description. For instance, in North America a BAC of 0.1 means that there are 0.10 g of alcohol for every dL of blood, to calculate estimated peak blood alcohol concentration, a variation, including drinking period in hours, of the Widmark formula was used. The formula is, E B A C = ×10 where,0.806 is a constant for water in the blood. 10 converts the result to permillage of alcohol Regarding metabolism in the formula, female subjects on average had a higher percentage of body fat than males. When it does, an amount of alcohol is temporarily taken out of the blood. For this reason, most calculations of alcohol to body mass simply use the weight of the individual, finally, it is speculated that the bubbles in sparkling wine may speed up alcohol intoxication by helping the alcohol to reach the bloodstream faster. A study conducted at the University of Surrey in the United Kingdom gave subjects equal amounts of flat and sparkling Champagne which contained the same levels of alcohol. The National Institute on Alcohol Abuse and Alcoholism define the term binge drinking as a pattern of drinking that brings a person’s blood alcohol concentration to 0.08 grams percent or above. This typically happens when men consume 5 or more drinks, there are several different units in use around the world for defining blood alcohol concentration. Each is defined as either a mass of alcohol per volume of blood or a mass of alcohol per mass of blood,1 milliliter of blood has a mass of approximately 1.06 grams. Because of this, units by volume are similar but not identical to units by mass, in the U. S. the concentration unit 1% w/v is in use. This is not to be confused with the amount of alcohol measured on the breath, the amount of alcohol measured on the breath is generally accepted as proportional to the amount of alcohol present in the blood at a rate of 1,2100. Therefore, a measurement of 0.10 mg/L of breath alcohol converts to 0. 0001×2100 g/10dL. While a variety of units is used throughout the world, many use the g/L unit. Usual units are highlighted in the table below, for purposes of law enforcement, blood alcohol content is used to define intoxication and provides a rough measure of impairment. Although the degree of impairment may vary among individuals with the blood alcohol content, it can be measured objectively and is therefore legally useful. Most countries disallow operation of vehicles and heavy machinery above prescribed levels of blood alcohol content. Operation of boats and aircraft are also regulated, the alcohol level at which a person is considered legally impaired varies by country
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Biochemistry
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Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. By controlling information flow through biochemical signaling and the flow of energy through metabolism. Biochemistry is closely related to biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life. Depending on the definition of the terms used, molecular biology can be thought of as a branch of biochemistry, or biochemistry as a tool with which to investigate. The chemistry of the cell depends on the reactions of smaller molecules. These can be inorganic, for water and metal ions, or organic, for example the amino acids. The mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism, the findings of biochemistry are applied primarily in medicine, nutrition, and agriculture. In medicine, biochemists investigate the causes and cures of diseases, in nutrition, they study how to maintain health and study the effects of nutritional deficiencies. In agriculture, biochemists investigate soil and fertilizers, and try to discover ways to improve crop cultivation, crop storage and pest control. However, biochemistry as a scientific discipline has its beginning sometime in the 19th century, or a little earlier. Gowland Hopkins on enzymes and the nature of biochemistry. The term biochemistry itself is derived from a combination of biology, the German chemist Carl Neuberg however is often cited to have coined the word in 1903, while some credited it to Franz Hofmeister. Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea and these techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle. Another significant historic event in biochemistry is the discovery of the gene and this part of biochemistry is often called molecular biology. In the 1950s, James D. Watson, Francis Crick, Rosalind Franklin, in 1958, George Beadle and Edward Tatum received the Nobel Prize for work in fungi showing that one gene produces one enzyme. In 1988, Colin Pitchfork was the first person convicted of murder with DNA evidence, mello received the 2006 Nobel Prize for discovering the role of RNA interference, in the silencing of gene expression. Around two dozen of the 92 naturally occurring elements are essential to various kinds of biological life. Most rare elements on Earth are not needed by life, while a few common ones are not used, most organisms share element needs, but there are a few differences between plants and animals
25.
Antimony
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Antimony is a chemical element with symbol Sb and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite, Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name, kohl. Metallic antimony was known, but it was erroneously identified as lead upon its discovery. In the West, it was first isolated by Vannoccio Biringuccio, for some time, China has been the largest producer of antimony and its compounds, with most production coming from the Xikuangshan Mine in Hunan. The industrial methods for refining antimony are roasting and reduction with carbon or direct reduction of stibnite with iron, the largest applications for metallic antimony is an alloy with lead and tin and the lead antimony plates in lead–acid batteries. Alloys of lead and tin with antimony have improved properties for solders, bullets, Antimony compounds are prominent additives for chlorine and bromine-containing fire retardants found in many commercial and domestic products. An emerging application is the use of antimony in microelectronics, Antimony is in a pnictogen and has an electronegativity of 2.05. In accordance with periodic trends, it is more electronegative than tin or bismuth, Antimony is stable in air at room temperature, but reacts with oxygen if heated to produce antimony trioxide, Sb2O3. Antimony is resistant to attack by acids, four allotropes of antimony are known, a stable metallic form and three metastable forms. Elemental antimony is a brittle, silver-white shiny metalloid, when slowly cooled, molten antimony crystallizes in a trigonal cell, isomorphic with the gray allotrope of arsenic. A rare explosive form of antimony can be formed from the electrolysis of antimony trichloride, when scratched with a sharp implement, an exothermic reaction occurs and white fumes are given off as metallic antimony forms, when rubbed with a pestle in a mortar, a strong detonation occurs. Black antimony is formed upon cooling of antimony vapor. It has the crystal structure as red phosphorus and black arsenic, it oxidizes in air. At 100 °C, it transforms into the stable form. The yellow allotrope of antimony is the most unstable and it has only been generated by oxidation of stibine at −90 °C. Above this temperature and in ambient light, this metastable allotrope transforms into the more stable black allotrope, elemental antimony adopts a layered structure in which layers consist of fused, ruffled, six-membered rings. The nearest and next-nearest neighbors form an octahedral complex, with the three atoms in each double layer slightly closer than the three atoms in the next. This relatively close packing leads to a density of 6.697 g/cm3
26.
Strychnos nux-vomica
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The strychnine tree, also known as strychnine tree, nux vomica, poison nut, semen strychnos and quaker buttons, is a deciduous tree native to India, and southeast Asia. It is a tree in the family Loganiaceae that grows in open habitats. Its leaves are ovate and 2–3.5 inches in size and it is a major source of the highly poisonous, intensely bitter alkaloids strychnine and brucine, derived from the seeds inside the trees round, green to orange fruit. The seeds contain approximately 1. 5% strychnine, and the dried blossoms contain 1. 0%, however, the trees bark also contains brucine and other poisonous compounds. Strychnos is promoted within alternative medicine as a treatment for many conditions, the use of strychnine is highly regulated in many countries, and is mostly used in baits to kill feral mammals, including wild dogs, foxes, and rodents. Most accidental poisoning is by breathing in the powder or by absorption through the skin, Strychnos nux-vomica is a medium-sized tree with a short thick trunk. The wood is dense, hard white, and close-grained, the branches are irregular and are covered with a smooth ashen bark. The young shoots are a green colour with a shiny coat. The leaves have a decussate arrangement, short stalked, are oval shaped. The leaves are about 4 inches long and 3 inches wide, the flowers are small with a pale green colour with a funnel shape. They bloom in the season and have a foul smell. The fruit are about the size of an apple with a smooth. The flesh of the fruit is soft and white with a jelly-like pulp containing five seeds covered with a soft woolly substance, the seeds have the shape of a flattened disk completely covered with hairs radiating from the center of the sides. This gives the seeds a very characteristic sheen, the seeds are very hard, with a dark gray horny endosperm where the small embryo is housed that gives off no odor but possesses a very bitter taste. Strychnos is promoted within herbal medicine as being a treatment for a range of maladies including cancer. There is however no evidence it is useful for treating any condition, since the seeds contain strychnine poison, conventional doctors do not recommend it as a medicine. It is on the Commission E list of unapproved herbs, because it is not recommended for use and has not been proven to be safe or effective, in Ayurveda, hudar is a mixture containing Strychnos nux-vomica. The seeds are first immersed in water for five days, in milk for two days followed by their boiling in milk, in India, the quality/toxicity of traditional medical crude and processed Strychnos seeds can be controlled by examining the toxic alkaloids using established HPLC methods and/or HPLC-UV methods
27.
Abdomen
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The abdomen constitutes the part of the body between the thorax and pelvis, in humans and in other vertebrates. The region occupied by the abdomen is termed the abdominal cavity, in arthropods it is the posterior tagma of the body, it follows the thorax or cephalothorax. The abdomen stretches from the thorax at the diaphragm to the pelvis at the pelvic brim. The pelvic brim stretches from the joint to the pubic symphysis and is the edge of the pelvic inlet. The space above this inlet and under the thoracic diaphragm is termed the abdominal cavity, the boundary of the abdominal cavity is the abdominal wall in the front and the peritoneal surface at the rear. The abdomen contains most of the organs of the digestive tract. Hollow abdominal organs include the stomach, the intestine. Organs such as the liver, its attached gallbladder, and the function in close association with the digestive tract. The spleen, kidneys, and adrenal glands also lie within the abdomen, along with blood vessels including the aorta. Anatomists may consider the urinary bladder, uterus, fallopian tubes, finally, the abdomen contains an extensive membrane called the peritoneum. A fold of peritoneum may completely cover certain organs, whereas it may only one side of organs that usually lie closer to the abdominal wall. Anatomists call the type of organs retroperitoneal. For example, the stomach of ruminants is divided into four chambers – rumen, in vertebrates, the abdomen is a large cavity enclosed by the abdominal muscles, ventrally and laterally, and by the vertebral column dorsally. Lower ribs can also enclose ventral and lateral walls, the abdominal cavity is upper part of the pelvic cavity. It is attached to the cavity by the diaphragm. Structures such as the aorta, inferior vena cava and esophagus pass through the diaphragm, both the abdominal and pelvic cavities are lined by a serous membrane known as the parietal peritoneum. This membrane is continuous with the visceral peritoneum lining the organs, the abdomen in vertebrates contains a number of organs belonging, for instance, to the digestive tract and urinary system. There are three layers of the abdominal wall and they are, from the outside to the inside, external oblique, internal oblique, and transverse abdominal
28.
Liquefaction
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Liquefaction occurs both as part of natural processes, and in man-made processes used in science and commerce. In geology, soil liquefaction refers to the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, by undermining the foundations and base courses of infrastructure, liquefaction can cause serious damage. In physics and chemistry, the transitions from solid and gas to liquid may be referred to as liquefaction. The melting point is the temperature and pressure at which a solid becomes a liquid, in commercial and industrial situations, the process of condensing a gas to liquid is sometimes referred to as liquefaction of gases. Coal liquefaction is the production of fuels from coal using a variety of industrial processes. Liquefaction is also used in commercial and industrial settings to refer to mechanical dissolution of a solid by mixing, grinding or blending with a liquid. In kitchen or laboratory settings, solids may be chopped into smaller parts sometimes in combination with a liquid and this may be done with a blender, or liquidiser in British English. In biology, liquefaction often involves organic tissue turning into a more liquid-like state, for example, liquefactive necrosis in pathology, or liquefaction as a parameter in semen analysis
