1.
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
2.
Occupational safety and health
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These terms of course also refer to the goals of this field, so their use in the sense of this article was originally an abbreviation of occupational safety and health program/department etc. The goals of occupational safety and health programs include to foster a safe, OSH may also protect co-workers, family members, employers, customers, and many others who might be affected by the workplace environment. In the United States, the occupational health and safety is referred to as occupational health and occupational and non-occupational safety. In common-law jurisdictions, employers have a common law duty to take care of the safety of their employees. As defined by the World Health Organization occupational health deals with all aspects of health, Health has been defined as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. Occupational health is a field of healthcare concerned with enabling an individual to undertake their occupation. Health has been defined as It contrasts, for example, with the promotion of health and safety at work, since 1950, the International Labour Organization and the World Health Organization have shared a common definition of occupational health. It was adopted by the Joint ILO/WHO Committee on Occupational Health at its first session in 1950, the concept of working culture is intended in this context to mean a reflection of the essential value systems adopted by the undertaking concerned. Such a culture is reflected in practice in the systems, personnel policy, principles for participation, training policies. Professionals advise on a range of occupational health matters. The research and regulation of safety and health are a relatively recent phenomenon. As labor movements arose in response to concerns in the wake of the industrial revolution. The initial remit of the Inspectorate was to police restrictions on the hours in the textile industry of children. The commission sparked public outrage resulted in the Mines Act of 1842. Otto von Bismarck inaugurated the first social insurance legislation in 1883, similar acts followed in other countries, partly in response to labor unrest. Although work provides many economic and other benefits, an array of workplace hazards also present risks to the health. Personal protective equipment can protect against many of these hazards. Physical hazards affect many people in the workplace, Falls are also a common cause of occupational injuries and fatalities, especially in construction, extraction, transportation, healthcare, and building cleaning and maintenance
3.
Yeast
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Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The yeast lineage originated hundreds of millions of years ago, and 1,500 species are currently identified and they are estimated to constitute 1% of all described fungal species. Yeast sizes vary greatly, depending on species and environment, typically measuring 3–4 µm in diameter, most yeasts reproduce asexually by mitosis, and many do so by the asymmetric division process known as budding. Yeasts, with their growth habit, can be contrasted with molds. Fungal species that can take both forms are called dimorphic fungi and it is also a centrally important model organism in modern cell biology research, and is one of the most thoroughly researched eukaryotic microorganisms. Researchers have used it to information about the biology of the eukaryotic cell. Other species of yeasts, such as Candida albicans, are opportunistic pathogens, yeasts have recently been used to generate electricity in microbial fuel cells, and produce ethanol for the biofuel industry. Yeasts do not form a taxonomic or phylogenetic grouping. The budding yeasts are classified in the order Saccharomycetales, within the phylum Ascomycota, the word yeast comes from Old English gist, gyst, and from the Indo-European root yes-, meaning boil, foam, or bubble. Yeast microbes are probably one of the earliest domesticated organisms, archaeologists digging in Egyptian ruins found early grinding stones and baking chambers for yeast-raised bread, as well as drawings of 4, 000-year-old bakeries and breweries. In 1680, Dutch naturalist Anton van Leeuwenhoek first microscopically observed yeast, but at the time did not consider them to be living organisms, researchers were doubtful whether yeasts were algae or fungi, but in 1837 Theodor Schwann recognized them as fungi. In 1857, French microbiologist Louis Pasteur proved in the paper Mémoire sur la fermentation alcoolique that alcoholic fermentation was conducted by living yeasts and not by a chemical catalyst. Pasteur showed that by bubbling oxygen into the yeast broth, cell growth could be increased, by the late 18th century, two yeast strains used in brewing had been identified, Saccharomyces cerevisiae and S. carlsbergensis. S. cerevisiae has been sold commercially by the Dutch for bread-making since 1780, while, around 1800, in 1825, a method was developed to remove the liquid so the yeast could be prepared as solid blocks. The industrial production of yeast blocks was enhanced by the introduction of the press in 1867. In 1872, Baron Max de Springer developed a process to create granulated yeast. Yeasts are chemoorganotrophs, as they use organic compounds as a source of energy, carbon is obtained mostly from hexose sugars, such as glucose and fructose, or disaccharides such as sucrose and maltose. Some species can metabolize pentose sugars such as ribose, alcohols, Yeast species either require oxygen for aerobic cellular respiration or are anaerobic, but also have aerobic methods of energy production
4.
Herring
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Herring are forage fish, mostly belonging to the family Clupeidae. Herring often move in schools around fishing banks and near the coast. Three species of Clupea are recognised, and provide about 90% of all captured in fisheries. Most abundant of all is the Atlantic herring, providing half of all herring capture. Fishes called herring are found in India, in the Arabian Sea, Indian Ocean. Herring played a role in the history of marine fisheries in Europe. These oily fish also have a history as an important food fish. A number of different species, most belonging to the family Clupeidae, are referred to as herrings. The origins of the herring is somewhat unclear, though it may derive from the Old High German heri meaning a host, multitude. The type genus of the herring family Clupeidae is Clupea, Clupea contains three species, the Atlantic herring found in the north Atlantic, the Pacific herring found in the north Pacific, and the Araucanian herring found off the coast of Chile. Subspecific divisions have been suggested for both the Atlantic and Pacific herrings, but their biological basis remain unclear, in addition, a number of related species, all in the family Clupeidae, are commonly referred to as herrings. The table immediately below includes those members of the Clupeidae family referred to by FishBase as herrings which have been assessed by the International Union for Conservation of Nature. There are also a number of other species called herrings, which may be related to clupeids or just share some characteristics of herrings. Just which of these species are called herrings can vary with locality, some examples, The species of Clupea belong to the larger family Clupeidae, which comprises some 200 species that share similar features. These silvery-coloured fish have a dorsal fin, which is soft. They have no lateral line and have a lower jaw. At least one stock of Atlantic herring spawns in every month of the year, each spawns at a different time and place. Greenland populations spawn in 0–5 metres of water while North Sea herrings spawn at up to 200 metres in autumn
5.
Wheat
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Wheat is a cereal grain, originally from the Levant region but now cultivated worldwide. In 2016, world production of wheat was 749 million tonnes, making it the second most-produced cereal after maize, since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st Century. This grain is grown on land area than any other commercial food. World trade in wheat is greater than for all other crops combined, globally, wheat is the leading source of vegetal protein in human food, having a protein content of about 13%, which is relatively high compared to other major cereals and staple foods. The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BCE. In a small part of the population, gluten – the major part of wheat protein – can trigger coeliac disease, non-coeliac gluten sensitivity, gluten ataxia. Cultivation and repeated harvesting and sowing of the grains of wild grasses led to the creation of domestic strains, in domesticated wheat, grains are larger, and the seeds remain attached to the ear by a toughened rachis during harvesting. In wild strains, a more fragile rachis allows the ear to easily shatter, as the traits that improve wheat as a food source also involve the loss of the plants natural seed dispersal mechanisms, highly domesticated strains of wheat cannot survive in the wild. Cultivation of wheat began to spread beyond the Fertile Crescent after about 8000 BCE, jared Diamond traces the spread of cultivated emmer wheat starting in the Fertile Crescent sometime before 8800 BCE. Archaeological analysis of wild emmer indicates that it was first cultivated in the southern Levant with finds dating back as far as 9600 BCE, Genetic analysis of wild einkorn wheat suggests that it was first grown in the Karacadag Mountains in southeastern Turkey. Dated archeological remains of wheat in settlement sites near this region, including those at Abu Hureyra in Syria. With the anomalous exception of two grains from Iraq ed-Dubb, the earliest carbon-14 date for einkorn wheat remains at Abu Hureyra is 7800 to 7500 years BCE. Remains of harvested emmer from several sites near the Karacadag Range have been dated to between 8600 and 8400 BCE, that is, in the Neolithic period and these remains were dated by Willem van Zeist and his assistant Johanna Bakker-Heeres to 8800 BCE. They also concluded that the settlers of Tell Aswad did not develop this form of emmer themselves, the cultivation of emmer reached Greece, Cyprus and India by 6500 BCE, Egypt shortly after 6000 BCE, and Germany and Spain by 5000 BCE. The early Egyptians were developers of bread and the use of the oven, by 3000 BCE, wheat had reached the British Isles and Scandinavia. A millennium later it reached China, the oldest evidence for hexaploid wheat has been confirmed through DNA analysis of wheat seeds, dating to around 6400-6200 BCE, recovered from Çatalhöyük. The first identifiable bread wheat with sufficient gluten for yeasted breads has been identified using DNA analysis in samples from a dating to approximately 1350 BCE at Assiros in Macedonia. From Asia, wheat continued to spread throughout Europe, in the British Isles, wheat straw was used for roofing in the Bronze Age, and was in common use until the late 19th century
6.
DNA
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Deoxyribonucleic acid is a molecule that carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and RNA are nucleic acids, alongside proteins, lipids and complex carbohydrates, most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix. The two DNA strands are termed polynucleotides since they are composed of simpler units called nucleotides. Each nucleotide is composed of one of four nitrogen-containing nucleobases—cytosine, guanine, adenine, or thymine —a sugar called deoxyribose, and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. The nitrogenous bases of the two polynucleotide strands are bound together, according to base pairing rules, with hydrogen bonds to make double-stranded DNA. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037, in comparison the total mass of the biosphere has been estimated to be as much as 4 trillion tons of carbon. The DNA backbone is resistant to cleavage, and both strands of the double-stranded structure store the same biological information and this information is replicated as and when the two strands separate. A large part of DNA is non-coding, meaning that these sections do not serve as patterns for protein sequences, the two strands of DNA run in opposite directions to each other and are thus antiparallel. Attached to each sugar is one of four types of nucleobases and it is the sequence of these four nucleobases along the backbone that encodes biological information. RNA strands are created using DNA strands as a template in a process called transcription, under the genetic code, these RNA strands are translated to specify the sequence of amino acids within proteins in a process called translation. Within eukaryotic cells DNA is organized into structures called chromosomes. During cell division these chromosomes are duplicated in the process of DNA replication, eukaryotic organisms store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts. In contrast prokaryotes store their DNA only in the cytoplasm, within the eukaryotic chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed, DNA was first isolated by Friedrich Miescher in 1869. DNA is used by researchers as a tool to explore physical laws and theories, such as the ergodic theorem. The unique material properties of DNA have made it an attractive molecule for material scientists and engineers interested in micro-, among notable advances in this field are DNA origami and DNA-based hybrid materials. DNA is a polymer made from repeating units called nucleotides
7.
Bovinae
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The evolutionary relationship between the members of the group is still debated, and their classification into loose tribes rather than formal subgroups reflects this uncertainty. General characteristics include cloven hoofs and usually at least one of the sexes of a species having true horns, the largest extant bovine is the gaur. In most countries, bovids are used for food, cattle are eaten almost everywhere except in parts of India and Nepal where they are considered sacred by most Hindus. Bos comes from the Indo-European root *gwous, meaning ox, international Commission on Zoological Nomenclature Opinion 2027. Usage of 17ΔбГ specific names based on species which are pre-dated by or contemporary with those based on domestic animals. Congress on Controversies in Bovine Health, Industry & Economics
8.
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
9.
RNA
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Ribonucleic acid is a polymeric molecule essential in various biological roles in coding, decoding, regulation, and expression of genes. RNA and DNA are nucleic acids, and, along with proteins and carbohydrates, like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single-strand folded onto itself, rather than a paired double-strand. Cellular organisms use messenger RNA to convey information that directs synthesis of specific proteins. Many viruses encode their genetic information using an RNA genome, some RNA molecules play an active role within cells by catalyzing biological reactions, controlling gene expression, or sensing and communicating responses to cellular signals. One of these processes is protein synthesis, a universal function where RNA molecules direct the assembly of proteins on ribosomes. This process uses transfer RNA molecules to deliver amino acids to the ribosome, analysis of these RNAs has revealed that they are highly structured. Unlike DNA, their structures do not consist of long double helices, in this fashion, RNAs can achieve chemical catalysis. For instance, determination of the structure of the enzyme that catalyzes peptide bond formation—revealed that its active site is composed entirely of RNA. Each nucleotide in RNA contains a sugar, with carbons numbered 1 through 5. A base is attached to the 1 position, in general, adenine, cytosine, guanine, adenine and guanine are purines, cytosine and uracil are pyrimidines. A phosphate group is attached to the 3 position of one ribose, the phosphate groups have a negative charge each, making RNA a charged molecule. The bases form hydrogen bonds between cytosine and guanine, between adenine and uracil and between guanine and uracil, however, other interactions are possible, such as a group of adenine bases binding to each other in a bulge, or the GNRA tetraloop that has a guanine–adenine base-pair. An important structural feature of RNA that distinguishes it from DNA is the presence of a group at the 2 position of the ribose sugar. The A-form geometry results in a deep and narrow major groove. RNA is transcribed with only four bases, but these bases, pseudouridine, in which the linkage between uracil and ribose is changed from a C–N bond to a C–C bond, and ribothymidine are found in various places. Another notable modified base is hypoxanthine, a deaminated adenine base whose nucleoside is called inosine, inosine plays a key role in the wobble hypothesis of the genetic code. The specific roles of many of these modifications in RNA are not fully understood, the functional form of single-stranded RNA molecules, just like proteins, frequently requires a specific tertiary structure. The scaffold for this structure is provided by secondary structural elements that are hydrogen bonds within the molecule and this leads to several recognizable domains of secondary structure like hairpin loops, bulges, and internal loops
10.
Sperm
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Sperm is the male reproductive cell and is derived from the Greek word sperma. In the types of reproduction known as anisogamy and its subtype oogamy. A uniflagellar sperm cell that is motile is referred to as a spermatozoon, Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a new organism begins developing, starting as a totipotent zygote. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the egg to form a diploid cell. In mammals, sperm develops in the testicles and is released from the penis, the mammalian sperm cell consists of a head, neck, a midpiece and a tail. The head contains the nucleus with densely coiled chromatin fibres, surrounded anteriorly by an acrosome, the neck contains the sperm centriole. The midpiece has a central core with many mitochondria spiralled around it, used for ATP production for the journey through the female cervix, uterus. The tail or flagellum executes the lashing movements that propel the spermatocyte, although semen contains millions of sperm, the egg will admit only one. The other ones will die and be absorbed. The spermatozoa of animals are produced through spermatogenesis inside the gonads via meiotic division. The initial spermatozoon process takes around 70 days to complete, the spermatid stage is where the sperm develops the familiar tail. The next stage where it becomes fully mature takes around 60 days when it is called a spermatozoan, Sperm cells are carried out of the male body in a fluid known as semen. Human sperm cells can survive within the reproductive tract for more than 5 days post coitus. Semen is produced in the vesicles, prostate gland and urethral glands. In 2016 scientists at Nanjing Medical University claimed they had produced cells resembling mouse spermatids artificially from stem cells and they injected these spermatids into mouse eggs and produced pups. Sperm quantity and quality are the parameters in semen quality. Thus, in humans, it is a measure of fertility in a man, the genetic quality of sperm, as well as its volume and motility, all typically decrease with age. Human sperm cells are vulnerable to free radical attack and the generation of oxidative DNA damage
11.
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
12.
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
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