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Trituration
Trituration (Latin, ''grinding'') is the name of several different methods used to process materials. In one sense, it is a form of comminution (reducing the particle size of a substance). In another sense, it is the production of a homogeneous powdered material by mixing and grinding component materials thoroughly. For example, a dental amalgam is formed by combining particles of a metal, usually gold or silver, with mercury. *In organic chemistry, trituration is a process used to purify crude chemical compounds containing soluble impurities. A solvent is chosen in which the desired product is insoluble and the undesired by-products are very soluble or vice versa. For example, when the impurities are soluble and the desired product is not, the crude material is washed with the solvent and filtered, leaving the purified product in solid form and any impurities in solution. If mixed solvents are used, target compound and impurities are first dissolved in small amount of solvent, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comminution
Comminution is the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, cutting, vibrating, or other processes. In geology, it occurs naturally during faulting in the upper part of the Earth's crust. In industry, it is an important unit operation in mineral processing, ceramics, electronics, and other fields, accomplished with many types of mill. In dentistry, it is the result of mastication of food. In general medicine, it is one of the most traumatic forms of bone fracture. Within industrial uses, the purpose of comminution is to reduce the size and to increase the surface area of solids. It is also used to free useful materials from matrix materials in which they are embedded, and to concentrate minerals. Energy requirements The comminution of solid materials consumes energy, which is being used to break up the solid into smaller pieces. The comminution energy can be estimated by: * Rittinger's law, which assu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Amalgam
Dental amalgam is a liquid mercury and metal alloy mixture used in dentistry to fill cavities caused by tooth decay. Low-copper amalgam commonly consists of mercury (50%), silver (~22–32%), tin (~14%), zinc (~8%) and other trace metals. Dental amalgams were first documented in a Tang Dynasty medical text written by Su Gong (苏恭) in 659, and appeared in Germany in 1528. In the 1800s, amalgam became the dental restorative material of choice due to its low cost, ease of application, strength, and durability. In July 2018 the EU prohibited amalgam for dental treatment of children under 15 years and of pregnant or breastfeeding women. History of use There are, according to Geir Bjørklund, indications that dental amalgam was used in the first part of the Tang Dynasty in China (AD 618–907), and in Germany by Strockerus in about 1528. Evidence of a dental amalgam first appears in the Tang Dynasty medical text ''Xinxiu bencao''《新修本草》 written by Su Gong (苏恭) i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homeopathy
Homeopathy or homoeopathy is a pseudoscientific system of alternative medicine. It was conceived in 1796 by the German physician Samuel Hahnemann. Its practitioners, called homeopaths, believe that a substance that causes symptoms of a disease in healthy people can cure similar symptoms in sick people; this doctrine is called '' similia similibus curentur'', or "like cures like". Homeopathic preparations are termed ''remedies'' and are made using homeopathic dilution. In this process, the selected substance is repeatedly diluted until the final product is chemically indistinguishable from the diluent. Often not even a single molecule of the original substance can be expected to remain in the product. Between each dilution homeopaths may hit and/or shake the product, claiming this makes the diluent remember the original substance after its removal. Practitioners claim that such preparations, upon oral intake, can treat or cure disease. All relevant scientific knowledge about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tissue (biology)
In biology, tissue is a biological organizational level between cells and a complete organ. A tissue is an ensemble of similar cells and their extracellular matrix from the same origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues. The English word "tissue" derives from the French word "tissu", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology. Xavier Bichat is considered as the "Father of Histology". Plant histology is studied in both plant anatomy and physiology. The classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned, the histological stain, and the optical microscope. Developments in electron microscopy, immunofluorescence, and the use of frozen tissue-sections have enhanced the detail that can be observed in tissues. With these tools, the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physical structure of biological macromolecules is known as molecular biology. Molecular biology was first described as an approach focused on the underpinnings of biological phenomena - uncovering the structures of biological molecules as well as their interactions, and how these interactions explain observations of classical biology. In 1945 the term molecular biology was used by physicist William Astbury. In 1953 Francis Crick, James Watson, Rosalind Franklin, and colleagues, working at Medical Research Council unit, Cavendish laboratory, Cambridge (now the MRC Laboratory of Molecular Biology), made a double helix model of DNA which changed the entire research scenario. They proposed the DNA structure based on previous research done by Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water-soluble
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be " miscible in all proportions" (or just "miscible"). The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations,J. de Swaan Arons and G. A. M. Diepen (1966): "Gas—Gas Equilibria". ''Journal of Chemical Physics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactose
Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix '' -ose'' used to name sugars. The compound is a white, water-soluble, non-hygroscopic solid with a mildly sweet taste. It is used in the food industry. Structure and reactions Lactose is a disaccharide derived from the condensation of galactose and glucose, which form a β-1→4 glycosidic linkage. Its systematic name is β-D-galactopyranosyl-(1→4)-D-glucose. The glucose can be in either the α-pyranose form or the β-pyranose form, whereas the galactose can only have the β-pyranose form: hence α-lactose and β-lactose refer to the anomeric form of the glucopyranose ring alone. Detection reactions for lactose are the Woehlk- and Fearon's test. Both can be easily used in school experiments to visualise the different lactose content o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juicer
A juicer, also known as a juice extractor, is a tool used to extract juice from fruits, herbs, leafy greens and other types of vegetables in a process called juicing. It crushes, grinds, and/or squeezes the juice out of the Juice vesicles, pulp. Some types of juicers can also function as a food processor. Most of the twin gear and horizontal masticating juicers have attachments for crushing herbs and spices, extruding pasta, noodles or bread sticks, making baby food and nut butter, grinding coffee, making nut milk, etc. Types Reamers Lemon squeezer, Squeezers are used for squeezing juice from citrus such as grapefruits, lemons, lime (fruit), limes, and orange (fruit), oranges. Juice is extracted by pressing or grinding a halved citrus along a juicer's ridged conical center and discarding the rind. Some reamers are stationary and require a user to press and turn the fruit, while others are electrical, automatically turning the ridged center when fruit is pressed upon. Centrifug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juicing
Juicing is the process of extracting juice from plant tissues such as fruit or vegetables. Overview There are many methods of juicing, from squeezing fruit by hand to wide-scale extraction with industrial equipment. Juicing is generally the preferred method of consuming large amounts of produce quickly and is often completed with a household appliance called a juicer, which may be as simple as a cone upon which fruit is mashed or as sophisticated as a variable-speed, motor-driven device. It may also refer to the act of extracting and then drinking juice or those who extract the juice. Juicing is different from buying juice in the supermarket because it focuses on fresh pressed fruits and vegetables. Residential juicing is often practiced for dietary reasons or as a form of alternative medicine. Becoming first popular in the early 1970s, interest in juicing has since increased. Films such as ''Fat, Sick and Nearly Dead'', ''Food Matters'', and '' Hungry for Change'' have inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oral Contraceptive Formulations
Birth control pills come in a variety of formulations. The main division is between combined oral contraceptive pills, containing both estrogens and synthetic progestogens (progestins), and progestogen only pills. Combined oral contraceptive pills also come in varying types, including varying doses of estrogen, and whether the dose of estrogen or progestogen changes from week to week. Mechanism of action Combination pills usually work by preventing the ovaries from releasing eggs (ovulation). They also thicken the cervical mucus, which keeps sperm from penetrating into the uterus and joining with an egg. The hormones in combination and progestogen-only pills also thin the lining of the uterus. This could prevent pregnancy by interfering with implantation of a blastocyst. Main action in typical use is prevention of ovulation. Combined oral contraceptive pills All contain an estrogen, ethinylestradiol or mestranol, in varying amounts, and one of a number of different progestogens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levonorgestrel
Levonorgestrel is a hormonal medication which is used in a number of birth control methods. It is combined with an estrogen to make combination birth control pills. As an emergency birth control, sold under the brand name Plan B One-Step among others, it is useful within 72 hours of unprotected sex. The more time that has passed since sex, the less effective the medication becomes, and it does not work after pregnancy ( implantation) has occurred. Levonorgestrel works by preventing ovulation or fertilization from occurring. It decreases the chances of pregnancy by 57 to 93%. In an intrauterine device (IUD), such as Mirena among others, it is effective for the long-term prevention of pregnancy. A levonorgestrel-releasing implant is also available in some countries. Common side effects include nausea, breast tenderness, headaches, and increased, decreased, or irregular menstrual bleeding. When used as an emergency contraceptive, if pregnancy occurs, there is no evidence that i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmacy
Pharmacy is the science and practice of discovering, producing, preparing, dispensing, reviewing and monitoring medications, aiming to ensure the safe, effective, and affordable use of medicines. It is a miscellaneous science as it links health sciences with pharmaceutical sciences and natural sciences. The professional practice is becoming more clinically oriented as most of the drugs are now manufactured by pharmaceutical industries. Based on the setting, pharmacy practice is either classified as community or institutional pharmacy. Providing direct patient care in the community of institutional pharmacies is considered clinical pharmacy. The scope of pharmacy practice includes more traditional roles such as compounding and dispensing of medications. It also includes more modern services related to health care including clinical services, reviewing medications for safety and efficacy, and providing drug information. Pharmacists, therefore, are experts on drug therapy and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
