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Compact Cassette tape types and formulations Relatively large (up to in length), irregularly-shaped oxide particles have protruding branches or dendrites; these irregularities prevent tight packing of particles, reducing iron content of the magnetic layer and, consequently, its remanence (13001400G) and maximum output level. Squareness ratio is mediocre, around 0.75, resulting in early but smooth onset of distortion. These tapes, historically sold as 'low noise', have high level of hiss and relatively low sensitivity; their optimal bias level is 1-2dB lower than that of IEC reference. The group also includes most of so-called 'type 0' cassettes - a mixed bag of ferric tapes that do not meet the IEC standard or the original Philips specification. Historically, informal 'type 0' denoted early cassettes loaded with tape designed for reel-to-reel recorders. In the 1980s many otherwise decent and usable basic tapes were effectively demoted to 'type 0' status when equipment manufacturers began aligning their decks to premium ferricobalts (the latter having much higher sensitivity and bias). In the XXI century 'type 0' denotes all sorts of low-quality, counterfeit or otherwise unusable cassettes. They require unusually low bias, and even then only few of them perform on par with quality ferrics. A 'type 0', if usable at all, is incompatible with Dolby noise reduction: with Dolby decoder engaged, the tape sounds dull, its poor sensitivity causes severe Dolby mistracking | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations In the beginning of the 1970s, gradual technological improvements of the previous decade resulted in the second generation of Type I tapes. These tapes had uniformly needle-shaped, highly orientable particles (HOP) of much smaller size, around in length, hence the trade term "microferrics". Uniform shape allowed very dense packing of particles, with less binder and more particles per unit volume, and a corresponding rise in remanence to around . The first microferric (TDK SD) was introduced in 1971, and in 1973 Pfizer began marketing patented microferric powder that soon became an industry standard. The next step was to align needle-shaped particles in parallel with flux lines generated by recording head; this was done by controlled flow of liquid magnetic mix over substrate (rheological orientation), or by applying strong magnetic field while the binder was curing. Typical microferric cassettes of the 1980s had lesser hiss and at least higher MOL than basic ferrics, at the cost of increased print-through. Small improvements continued for thirty years, with a gradual rise of squareness ratio from 0.75 to over 0.9. Newer tapes consistently produced higher output at less distortion at the same levels of bias and audio recording signals. Transition was smooth; after introduction of new, superior formulations manufacturers often kept older ones in production, selling them in different markets or under different, cheaper, designations | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations Thus, for example, TDK ensured that its premium microferric AD cassette was always ahead of entry-level microferric D, having finer particles and lower noise. The third, best performing class of ferric tapes is made of fine ferric particles encapsulated in a thin layer of cobalt-iron mix, similar in composition to cobalt ferrite. The first cobalt-doped cassettes, introduced by 3M in 1971, had exceptionally high sensitivity and MOL for the period, and were an even match for contemporary chromium dioxide tapes - hence the trade name "superferrics". Of many competing cobalt-doping technologies, the most widespread was low-temperature encapsulation of ferric oxide in aqueous solution of cobalt salts with subsequent drying at 100150°C. Encapsulated microferric particles retain needle-like shape and can be tightly packed into uniform anisotropic layers. The process was first commercialized in Japan in early 1970s. Remanence of ferricobalt cassettes is around , resulting in around gain in MOL and 23dB gain in sensitivity compared to basic ferrics; their hiss level is on par with contemporary microferric formulations. Dynamic range of the best ferricobalt cassettes (true superferrics) equals 6063dB dB; MOL at lower frequencies exceed MOL of Type IV tapes. Overall, superferrics are a good match to Type IV especially in recording acoustical music with a wide dynamic range | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations This was reflected in the price of top-of-the-line superferrics like Maxell XLI-S or TDK AR-X, which by 1992 matched the price of 'entry-level' metal tapes. IEC Type II tapes are intended for recording with high (150% of normal) bias and replay with 70μs time constant. All generations of Type II reference tapes, including the 1971 DIN reference that pre-dated the IEC standard, were manufactured by BASF. Type II has been historically known as 'chromium dioxide tape' or simply 'chrome tape', but in reality most of Type II cassettes do not contain chromium. The 'pseudochromes' (including almost all Type II's made by the Big Three Japanese makers - Maxell, Sony and TDK) are actually ferricobalt formulations optimized for Type II recording and playback settings. A true chrome tape must have a distinctive hot wax smell, which is missing in 'pseudochromes'. Both kinds of Type II have, on average, lower treble MOL and SOL, and higher signal-to-noise ratio than quality Type I tapes. This is caused by midrange and treble pre-emphasis applied during recording to match 70μs equalization at playback. In the middle of 1960s DuPont created and patented industrial process of making fine ferromagnetic particles of chromium dioxide (CrO). First CrO tapes for data and video appeared in 1968. In 1970 BASF, who would become the main proponent of CrO, launched its chrome cassette production; in the same year Advent introduced the first cassette deck with chrome capability and Dolby noise reduction | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations The combination of low noise CrO tape with electronic noise reduction brought a revolutionary improvement to compact cassette sound, almost reaching high fidelity standards. However, CrO tape required redesign of bias and replay equalization circuitry, and early formulations allegedly caused excessive head wear. These problems were solved during the 1970s but three unsolved issues remained: the cost of making CrO powder, the cost of royalties charged by DuPont, and the pollution effects of hexavalent chromium waste. Reference CrO tape, approved by the IEC in 1981, is characterized by coercivity of (high bias) and remanence of . Retail CrO cassettes had coercivity in the range from 400 to . Owing to very 'clean', uniform shape of the particles, chrome tapes easily attain almost perfect squareness ratio of 0.90. 'True chromes', not modified by addition of ferric additives or coatings, have very low and euphonic hiss (bias noise), and very low modulation noise at treble frequencies. Double-layer CrO cassettes have the lowest absolute noise among all audio formulations; these cassettes generate less noise at than a ferric tape at . Sensitivity is usually also very high, but MOL is low, on par with basic ferrics. CrO tape does not tolerate overload: onset of distortion is sharp and dissonant, so recording levels should be set conservatively, well below MOL. At low frequencies, MOL of CrO tapes rolls off faster than in ferric or metal tapes, hence the reputation of 'bass shyness' | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations CrO cassettes are best fit for recording dynamic music with rich harmonic content and relatively low bass levels; their dynamic range is a good fit for recording from uncompressed digital sources and for music with extended quiet passages. Good ferric tapes may have the same or higher treble SOL, but CrO tapes still sound subjectively better owing to lower hiss and modulation noise. CrO formulations are the least stable, and most prone to catastrophic degradation. At normal storage condition the tape remains usable for decades, but the recorded level slowly decreases at a rate of around 2 dB over the estimated lifetime (10 to 30 years). When storage temperature increases, chromium - a natural oxidizer of polyester and polyurethane binders - triggers irreversible decomposition of polymers. Remnants of broken macromolecules drift to the surface, causing excessive friction, then an increase in noise level, and finally magnetic layer breaks up into a sticky paste. A superficially similar, but chemically different sticky-shed syndrome affects certain reel-to-reel ferric tapes, but has never been recorded in Type I or ferricobalt Type II cassettes. After the introduction of CrO cassettes Japanese companies began developing a royalty-free alternative to DuPont's patent, based on already established cobalt doping process. A controlled increase in cobalt content causes an almost linear increase in coercivity, thus a Type II 'pseudochrome' can be made by simply adding around 3% cobalt to a Type I ferricobalt | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations By 1974 the technology was ready for mass production; TDK and Maxell introduced their classic 'pseudochromes' (TDK SA and Maxell UD-XL), and killed their true chrome lines (TDK KR and Maxell CR). By 1976 ferricobalt formulations took over the video tape market, eventually they became "the" dominant high-performance tape for audio cassette. Chromium dioxide disappeared from Japanese domestic market, but elsewhere it coexisted, as a distant second, with 'pseudochromes' until the very end of cassette era. Ferricobalt technology developed continuously; in the 1980s Japanese companies introduced 'premium' double-layered ferricobalts with exceptionally high MOL and SOL, in the middle of the 1990s TDK launched the first and only triple-coated ferricobalt, the SA-XS. Electroacoustic properties of Type II ferricobalts are very close to those of their Type I cousins. Due to replay equalization, hiss level is lower, but so is the treble saturation level. Dynamic range of Type II ferricobalts, according to the 1990 tests, lies between 60 and 65dB. Coercivity of 580700Oe and remanence of 13001550G are close to the CrO reference, but the difference is big enough to cause compatibility problems. A deck biased to IEC Type II reference cannot correctly record on Japanese ferricobalts; a Japanese deck biased to TDK SA (which was the informal reference in Japan) cannot correctly record on BASF or PDM CrO cassettes | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations Since the Japanese already dominated both cassette and hi-fi equipment markets, incompatibility further undermined market share of European-made decks and CrO cassette. By 1990 even BASF switched to making and selling Type II ferricobalts. In 1994 the IEC resolved the compatibility issue by appointing a new Type II reference tape - a BASF ferricobalt with properties very close to contemporary TDK tapes. By this time BASF had already already replaced their last true chrome tape with a hybrid CrO-ferricobalt formulation (the 1993 Chrome Plus). Coercivity of iron-cobalt MP mix, precipitated from aqueous solutions, depends on cobalt content. A change in cobalt content from 0 to 30% causes a gradual rise in coercivity from around (Type I level) to (Type IV level); alloyed iron-cobalt particles can reach coercivity of . This makes possible manufacturing of MP tapes conforming to Type II and even Type I biasing requirements. In practice, only Denon, Taiyo Yuden and, for only a few years TDK ever attempted making Type II metal tape. These rare expensive cassettes were characterized by high remanenence, approaching that of Type IV (); their coercivity of was closer to Type II than Type IV, but still quite far from either type reference. Independent tests of the 1990 Denon and Taiyo Yuden tapes placed them on the very top of Type II spectrum - "if" the recording deck could cope with unusually high sensitivity and provide unusually high bias current | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations In 1973 Sony introduced double-layer ferrichrome tapes, having a five-micron ferric base coated with one micron of CrO pigment. The new cassettes were advertized as 'the best of both worlds' - combining good low-frequency MOL of microferric tapes with good treble performance of chrome tapes. The novelty became part of the IEC standard, codenamed Type III; the Sony CS301 formulation became the IEC reference. However, the idea failed to attract followers; apart from Sony, only BASF and Agfa introduced their own ferrrichrome cassettes. These expensive tapes never gained substantial market share, and after the release of metal tapes they lost their perceived exclusivity. Their place in the market was taken over by superior and less expensive ferricobalt formulations. By 1983, tape deck manufacturers stopped providing Type III recording option. Ferrichrome tape remained in BASF and Sony lineups until 1984 and 1988 respectively. Pure metal particles have an inherent advantage over oxide particles due to 34times higher remanence, very high coercivity and far smaller particle size resulting in lower noise and high dynamic range. First attempts to make metal particle (MP), rather than metal "oxide" particle, tape date back to 1946; viable iron-cobalt-nickel formulations appeared in 1962. In early 1970s Philips began development of MP formulations for Compact Cassette. Contemporary powder metallurgy could not yet produce fine, submicron size particles, and properly passivate these highly pyrophoric powders | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations Although the latter problem were soon solved, the chemists did not convince the market in long-term stability of MP tapes; suspicions of inevitable early degradation persisted until the end of cassette era. The fears did not materialize: most metal tapes survived decades of storage just as good as ferrics; however, signals recorded on metal tapes do degrade at about the same rate as in chromium tapes, around 2dB over the estimated lifetime of the cassette. Metal particle Compact Cassettes, or simply 'metals', were introduced in 1979 and were soon standardized by the IEC as Type IV. They share the replay time constant with Type II, and can be correctly reproduced by any deck equipped with Type II equalization. Metal tapes cause far less head wear than oxide formulations. However, recording onto a metal tape requires special high-flux magnetic heads and high-current amplifiers to drive them. Typical metal tape is characterized by remanence of 30003500G and coercivity of 1100Oe, thus its bias flux is set at 250% of Type I level. Traditional glass ferrite heads would saturate their magnetic cores before reaching these levels. "Metal capable" decks had to be equipped with new heads built around sendust or permalloy cores, or the new generation of glass ferrite heads with specially treated gap materials. MP tapes, particularly top-of-the-line double coated tapes, have record high midrange MOL and treble SOL, and the widest dynamic range coupled with lowest distortion | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations They were always expensive, almost exclusive, out of reach of most consumers. They excel at reproducing fine nuances of uncompressed acoustic music, or music with very high treble content like brass and percussions. However, they need a high quality, properly aligned deck to reveal their potential. First-generation MP tapes were consistently similar in their biasing requirements, but by 1983 newer formulations drifted away from each other and the reference tape. Unlike previously described wet coating processes, metal evaropated (ME) media are fabricated by physical deposition of vaporized cobalt or cobalt-nickel mix in a vacuum chamber. There is no synthetic binder to hold particles together; instead, they adhere direcltly to polyester tape substrate. An electron beam melts source metal, creating a continuous directional flow of cobalt atoms towards the tape. The zone of contact between the beam and the tape is blown with a controlled flow of oxygen, which helps formation of polycrystalline metal-oxide coating. A massive liquid-cooled rotating drum, which pulls the tape into the contact zone, protects it from overheating. ME media, along with barium ferrite media, have the highest information density of all rerecordable media. The technology was introduced in 1978 by Panasonic, initially in the form of audio microcassettes, and matured through the 1980s | https://en.wikipedia.org/wiki?curid=63742889 |
Compact Cassette tape types and formulations Metal evaporated media established itself in analogue (Hi8) and digital (Digital8 and MicroMV) videotape market, and data storage (Advanced Intelligent Tape, Linear Tape Open). The technology seemed promising for analogue audio recording, however, very thin ME layers were too fragile for consumer cassette decks, and manufacturing costs were prohibitively high. Panasonic Type I, Type II and Type IV ME cassettes, introduced in 1984, were sold for only a few years in Japan alone, and remained unknown in the rest of the world. | https://en.wikipedia.org/wiki?curid=63742889 |
Chemistry—Methods is a peer-reviewed scientific journal that publishes articles on methods in chemistry. It is a fully open access journal published by Wiley-VCH on behalf of Chemistry Europe and is a sister publication to other scientific journals published by Wiley-VCH, including "Angewandte Chemie and Chemistry—A European Journal." The journal publishes interdisciplinary, original research covering topics such as operando methods in catalysis, new approaches to imaging, and new synthetic methods. The Editorial Board is chaired by Jana Roithová (Radboud Universiteit), Oliver Kappe (Universität Graz), and Steven Wheeler (University of Georgia, Athens). is part of Chemistry Europe, an association of 16 chemical societies from 15 European countries. It publishes a family of academic chemistry journals, including "Chemistry—A European Journal", "European Journal of Organic Chemistry", "European Journal of Inorganic Chemistry", Chemistry—Methods, "Batteries & Supercaps", "ChemBioChem", "ChemCatChem", "ChemElectroChem", "ChemMedChem", "ChemPhotoChem", "ChemPhysChem", "ChemPlusChem", "ChemSusChem", "ChemSystemsChem", "ChemistrySelect", "ChemistryOpen". | https://en.wikipedia.org/wiki?curid=63749121 |
ChemSystemsChem is a peer-reviewed scientific journal that publishes articles on all areas of systems chemistry. It is published by Wiley-VCH on behalf of Chemistry Europe and is a sister publication to other scientific journals published by Wiley-VCH, including "Angewandte Chemie and Chemistry—A European Journal." The journal publishes interdisciplinary, original research covering topics such as out-of-equilibrium self-assembly, chemical networks, and chemical ensembles with emergent properties. The Editorial Board is chaired by Ludovic Jullien (Sorbonne Université and École normale supérieure) and Wilhelm Huck (Radboud University). is part of Chemistry Europe, an association of 16 chemical societies from 15 European countries. It publishes a family of academic chemistry journals, including "Chemistry—A European Journal", "European Journal of Organic Chemistry", "European Journal of Inorganic Chemistry", "Chemistry—Methods", "Batteries & Supercaps", "ChemBioChem", "ChemCatChem", "ChemElectroChem", "ChemMedChem", "ChemPhotoChem", "ChemPhysChem", "ChemPlusChem", "ChemSusChem", ChemSystemsChem, "ChemistrySelect", "ChemistryOpen". | https://en.wikipedia.org/wiki?curid=63749309 |
Jacobus Kaper Jacobus Martinus Kaper (born 12 September 1931) is a biochemist and virologist who worked at the Henry A. Wallace Beltsville Agricultural Research Center of the Agricultural Research Service of the United States. He has performed research on the "cucumber mosaic virus". Kaper was born in Madjalenka, Dutch East Indies. He was elected corresponding member of the Royal Netherlands Academy of Arts and Sciences in 1980. | https://en.wikipedia.org/wiki?curid=63786428 |
ChemCatChem is a peer-reviewed scientific journal that publishes articles on heterogeneous, homogeneous, and biocatalysis. It is published by Wiley-VCH on behalf of Chemistry Europe and is a sister publication to other scientific journals published by Wiley-VCH, including "Angewandte Chemie and Chemistry—A European Journal." The Editorial Board is chaired by Wolfgang Kroutil (Karl-Franzens-Universität), Hermenegildo García (Universitat Politècnica de València), and A. Stephen K. Hashmi (Universität Heidelberg). According to the Journal Citation Reports, the journal has an impact factor of 4.495 (2018). is part of Chemistry Europe, an association of 16 chemical societies from 15 European countries. It publishes a family of academic chemistry journals, including "Chemistry—A European Journal", "European Journal of Organic Chemistry", "European Journal of Inorganic Chemistry", "Chemistry—Methods", "Batteries & Supercaps", "ChemBioChem", ChemCatChem, "ChemElectroChem", "ChemMedChem", "ChemPhotoChem", "ChemPhysChem", "ChemPlusChem", "ChemSusChem", "ChemSystemsChem", "ChemistrySelect", "ChemistryOpen". | https://en.wikipedia.org/wiki?curid=63788959 |
ChemElectroChem is a peer-reviewed scientific journal that publishes articles on pure and applied electrochemistry. It is published by Wiley-VCH on behalf of Chemistry Europe and is a sister publication to other scientific journals published by Wiley-VCH, including "Angewandte Chemie and Chemistry—A European Journal." The journal publishes original research covering topics such as energy applications, electrochemistry at interfaces/surfaces, photoelectrochemistry, and bioelectrochemistry. The Editorial Board is chaired by Bing-Wei Mao (Xiamen University), Flavio Maran (Università degli Studi di Padova), and Wolfgang Schuhmann (Ruhr-Universität Bochum). According to the Journal Citation Reports, the journal has an impact factor of 3.975 (2018). is part of Chemistry Europe, an association of 16 chemical societies from 15 European countries. It publishes a family of academic chemistry journals, including "Chemistry—A European Journal", "European Journal of Organic Chemistry", "European Journal of Inorganic Chemistry", "Chemistry—Methods", "Batteries & Supercaps", "ChemBioChem", "ChemCatChem", ChemElectroChem, "ChemMedChem", "ChemPhotoChem", "ChemPhysChem", "ChemPlusChem", "ChemSusChem", "ChemSystemsChem", "ChemistrySelect", "ChemistryOpen". | https://en.wikipedia.org/wiki?curid=63789111 |
ChemPhotoChem is a peer-reviewed scientific journal that publishes articles on pure and applied photochemistry. It is published by Wiley-VCH on behalf of Chemistry Europe and is a sister publication to other scientific journals published by Wiley-VCH, including "Angewandte Chemie and Chemistry—A European Journal." The journal publishes original research covering topics such as photovoltaics, photopharmacology, imaging, analytical chemistry, and synthesis. The Editorial Board is chaired by Kazunari Domen (University of Tokyo), Malcom Forbes (Bowling Green State University), Axel Griesbeck (Universität zu Köln), and Johan Hofkens (Katholieke Universiteit Leuven). is part of Chemistry Europe, an association of 16 chemical societies from 15 European countries. It publishes a family of academic chemistry journals, including "Chemistry—A European Journal", "European Journal of Organic Chemistry", "European Journal of Inorganic Chemistry", "Chemistry—Methods", "Batteries & Supercaps", "ChemBioChem", "ChemCatChem", "ChemElectroChem", "ChemMedChem", ChemPhotoChem, "ChemPhysChem", "ChemPlusChem", "ChemSusChem", "ChemSystemsChem", "ChemistrySelect", "ChemistryOpen". | https://en.wikipedia.org/wiki?curid=63789283 |
ChemistryOpen is a peer-reviewed scientific journal that publishes articles in all areas of chemistry and related fields. It is a fully open access journal published by Wiley-VCH on behalf of Chemistry Europe and is a sister publication to other scientific journals published by Wiley-VCH, including "Angewandte Chemie and Chemistry—A European Journal." was the first society-owned chemistry journal to be fully open access. The Editorial Board is chaired by Ramón Martinez-Máñez (Universitat Polytechnica de Valencia), Thomas Wirth (Cardiff University), Evamarie Hey-Hawkins (University of Leipzig), Jean-Marie Lehn (Université de Strasbourg). According to the Journal Citation Reports, the journal has an impact factor of 2.205 (2018). is part of Chemistry Europe, an association of 16 chemical societies from 15 European countries. It publishes a family of academic chemistry journals, including "Chemistry—A European Journal", "European Journal of Organic Chemistry", "European Journal of Inorganic Chemistry", "Chemistry—Methods", "Batteries & Supercaps", "ChemBioChem", "ChemCatChem", "ChemElectroChem", "ChemMedChem", "ChemPhotoChem", "ChemPhysChem", "ChemPlusChem", "ChemSusChem", "ChemSystemsChem", "ChemistrySelect", ChemistryOpen. | https://en.wikipedia.org/wiki?curid=63789420 |
Linear chain compound Linear chain compounds are materials composed of one-dimensional arrays of metal-metal bonded molecules or ions. Such materials exhibit anisotropic electrical conductivity. Most examples are composed of square planar complexes. Thus, upon crystallization, molecules of Rh(acac)(CO) stack with Rh---Rh distances of about 326 pm. Classic examples include Krogmann's salt and Magnus's green salt. Other examples include the partially oxidized derivatives of [Pt(oxalate)]. The otherwise ordinary complex IrBr(CO) gives an electrically conductive derivative upon oxidation. Such semiconducting materials are eniched in bromine, i.e. IrBr(CO), where x ~0.05. In contrast to linear chain compounds, extended metal atom chains (EMACs) are molecules or ions that consist of a finite, often short, linear strings of metal atoms, surrounded by organic ligands. One group of platinum chains is based on alternating cations and anions of [Pt(CNR)] (R = "i"Pr, "c-"CH, "p-"(CH)CH) and [Pt(CN)]. These may be able to be used as vapochromic sensor materials, or materials which change color when exposed to different vapors. Linear chains of Pd-Pd bonds protected by a “π-electron sheath are known. Not only do these olefin-stabilized metal chains constitute a significant contribution to the field of organometallic chemistry, both the complex's metal atom structures and the olefin ligands themselves can conduct a current. Some linear chain compounds are produced or fabricated by electrocrystallization | https://en.wikipedia.org/wiki?curid=63801647 |
Linear chain compound The technique is used to obtain single crystals of low-dimensional electrical conductors. | https://en.wikipedia.org/wiki?curid=63801647 |
Kennedy J. P. Orton (1872 - 1930) was a British chemist. Initially he studied medicine at St. Thomas' Hospital, but there he became interested in chemistry and moved to St. John's College, Cambridge. He then obtained a Ph. D. "summa cum laude" in Heidelberg under Karl von Auwers, before working for a year with Sir William Ramsey at University College, London. He was then lecturer and demonstrator of Chemistry at St. Bartholomew’s Hospital, before in 1903 being appointed Professor of Chemistry at University College of North Wales, Bangor, where he headed the department until his death. He was elected a Fellow of the Royal Society in 1921. Besides being a chemist, he was a keen climber and ornithologist, and a biannual ornithological lecture was endowed in his name. | https://en.wikipedia.org/wiki?curid=63805254 |
Nutrient testing in humans is a test that looks for deficiencies in a person body's amino acids, vitamins, antioxidants, minerals, and gives information about the immune response. Samples can be collected through blood or urine testing, and can provide detailed information about amino acid imbalances or potential excess. is aimed at identifying nutrient deficiencies that could be contributing to multiple health conditions. Some consider nutrient testing to be a key missing part of Western medical training. is considered by some to play a key role in optimizing health and preventing disease. If a patient is experiencing unresolved or undiagnosed symptoms, nutrient testing can provide a closer look at underlying deficiencies. is aimed at guiding patients and health providers in choosing the right vitamin for the right reason, as well as the adequate dose. Some nutritional supplement businesses provide nutrient testing kits delivered right to the client's door, allowing for blood samples to be mailed to the lab for analysis. | https://en.wikipedia.org/wiki?curid=63811696 |
Aporphine alkaloids are naturally occurring chemical compounds from the group of alkaloids. After the benzylisoquinoline alkaloids they are the second largest group of isoquinoline alkaloids. Up to now, 85 aporphine alkaloids have been isolated from plants of 15 families; the best known representative is apomorphine. The aporphine alkaloids are of interest mainly because of their similarity to morphine. The aporphine alkaloids are most commonly found in plants. For example, isoboldine can be found in the plants Beilschmiedia, Nandina (Nandina domestica), Horn poppy (Glaucium) and other plants. As the name suggests, glaucine was first found in the horn-poppy (glaucium) and usually the name of the alkaloids is derived from the plants in which they were first found. Corydin as a further representative of the aporphine alkaloids is found in the lark spurs (Corydalis), heart flowers (Dicentra) and also in the horny poppy (Glaucium). The aporphine alkaloids differ in their different substituents and their position on the base structure. Furthermore, their stereochemistry is partly different, most often they are ("R")-configured, but e.g. glaucine, bulbocapnine and isothebaine are ("S")-configured. Reticulin 1 is oxidized in the first step, resulting in a mesomery-stabilized diradical with the boundary structures 2a and 2b. Cyclization results in a fourth six-membered ring: corytuberin 3, which then dehydrates to bulbocapnin 4 | https://en.wikipedia.org/wiki?curid=63817585 |
Aporphine alkaloids Schematic diagram: The aporphine alkaloids are of particular interest because of their proximity to morphine and benzylisoquinoline alkaloids. For example, as the name suggests, morphine can be used to produce apomorphine. This can be done by adding an acid under the influence of heat. The proaporphin alkaloids and the aporphin alkaloids share a framework isomerism. The aporphine alkaloids usually have a stereocentre. The ("R")-configured glaucine can be synthesized from ("S")-glaucine. Apomorphine lowers blood pressure and is also a powerful emetic. It is mainly used as a remedy for Parkinson's disease because of its stimulating effect on dopamine receptors. In African traditional medicine, the plant Cassytha (Cassytha filiformis) is considered a medicine against cancer. A study showed that the plant contains many aporphine alkaloids and that the three main alkaloids actinodaphnin, cassythin and dicentrin have an indeed "in vitro" effect on cancer cells. | https://en.wikipedia.org/wiki?curid=63817585 |
Environmental impact of pharmaceuticals and personal care products The environmental effect of pharmaceuticals and personal care products (PPCPs) is currently being widely investigated. PPCPs include substances used by individuals for personal health or cosmetic reasons and the products used by agribusiness to boost growth or health of livestock. More than twenty million tons of PPCPs are produced every year. PPCPs have been detected in water bodies throughout the world. More research is needed to evaluate the risks of toxicity, persistence, and bioaccumulation, but the current state of research shows that personal care products impact over the environment and other species, such as coral reefs and fish. PPCPs encompass environmental persistent pharmaceutical pollutants (EPPPs) and are one type of persistent organic pollutants. They are not removed from wastewater by conventional methods. The European Union has declared pharmaceutical residues with the potential of contamination of water and soil to be "priority substances". Since the 1990s, water contamination by pharmaceuticals has been an environmental issue of concern. In addition, it is important to note that many public health professionals in the United States began writing reports of pharmaceutical contamination in waterways in the 1970s.” Most pharmaceuticals are deposited in the environment through human consumption and excretion, and are often filtered ineffectively by municipal sewage treatment plants which are not designed to manage them | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Once in the water, they can have diverse, subtle effects on organisms, although research is still limited. Pharmaceuticals may also be deposited in the environment through improper disposal, runoff from sludge fertilizer and reclaimed wastewater irrigation, and leaky sewer pipes. In 2009, an investigative report by Associated Press concluded that U.S. manufacturers had legally released 271 million pounds of compounds used as drugs into the environment, 92% of which was the industrial chemicals phenol and hydrogen peroxide, which are also used as antiseptics. It could not distinguish between drugs released by manufacturers as opposed to the pharmaceutical industry. It also found that an estimated 250 million pounds of pharmaceuticals and contaminated packaging were discarded by hospitals and long-term care facilities. The series of articles led to a hearing conducted by the U.S. Senate Subcommittee on Transportation Safety, Infrastructure Security, and Water Quality. This hearing was designed to address the levels of pharmaceutical contaminants in U.S. drinking water. This was the first time that pharmaceutical companies were questioned about their waste disposal methods. "No federal regulations or laws were created as a result of the hearing." "Between the years of 1970-2018 more than 3000 pharmaceutical chemicals were manufactured, but only 17 are screened or tested for in waterways | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products " Alternately, "There are no studies designed to examine the effects of pharmaceutical contaminated drinking water on human health.” In parallel, the European Union is the second biggest consumer in the world (24% of the world total) after the USA and in the majority of EU Member States, around 50% of unused human medicinal products is not collected to be disposed of properly. In the EU, between 30 and 90% of the orally administered doses are estimated to be excreted as the active substances in the urine. The term environmental persistent pharmaceutical pollutants (EPPP) was suggested in the 2010 nomination of pharmaceuticals and environment as an emerging issue to Strategic Approach to International Chemicals Management (SAICM) by the International Society of Doctors for the Environment (ISDE). Depending on the sources and ingredients, there are various ways in which the public can dispose of pharmaceutical and personal care products in acceptable ways. The most environmentally safe disposal method is to take advantage of a community drug take-back programs that collect drugs at a central location for proper disposal. Several local public health departments in the United States have initiated these programs. In addition, the United States Drug Enforcement Administration (DEA) periodically promotes local take-back programs, as well as the National Take Back Initiative | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Currently, take-back programs are funded by state or local health departments or are volunteer programs through pharmacies or health care providers. In recent years, the proposition that pharmaceutical companies should be responsible for their products “from the cradle to the grave,” has been gaining traction. This philosophy suggests that the manufacturers should fund the proper disposal of pharmaceutical products. Take-back programs should exist in every community, and, if further information is required on this, city officials should be contacted. If no such program exists locally, the Environmental Protection Agency and the Office of National Drug Control Policy suggest that consumers do the following: This will hopefully keep these chemicals separated from the open environment and especially water bodies long enough for them to naturally break down. When these substances find their way into water, it is much more difficult to deal with them. Water treatment facilities use different processes in order to minimize or fully eliminate these pollutants. This is done by using sorption where suspended solids are removed by sedimentation. Another method used is biodegradation, and through this method microorganisms, such as bacteria and fungi, feed on or break down these pollutants thus eliminating them from the contaminated media. Pharmaceuticals, or prescription and over-the-counter medications made for human use or veterinary or agribusiness purposes, are common PPCPs found in the environment | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products There are nine classes of pharmaceuticals included in PPCPs: hormones, antibiotics, lipid regulators, nonsteroidal anti-inflammatory drugs, beta-blockers, antidepressants, anticonvulsants, antineoplastics, and diagnostic contrast media. Personal care products have four classes: fragrances, preservatives, disinfectants, and sunscreen agents. These products may be found in cosmetics, perfumes, menstrual care products, lotions, shampoos, soaps, toothpastes, and sunscreen. These products typically enter the environment when passed through or washed off the body and into the ground or sewer lines, or when disposed of in the trash, septic tank, or sewage system. Traces of illicit drugs can be found in waterways and may even be carried by money. More attention has been devoted of late to PPCPs in the environment. Two causes may contribute to this: PPCPs are actually increasing in the environment due to widespread use and/or analytical technology is better able to detect PPCPs in the environment. These substances enter the environment directly or indirectly. Direct methods include contamination of surface water by hospitals, households, industries, or wastewater treatment plants. Direct contamination can also affect the sediment and soil. It is generally assumed (albeit hardly verified) that the production of pharmaceuticals in industrialised countries is well controlled and unharmful to the environment, due to the local legal restrictions usually required to permit production | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products However, a substantial fraction of the global production of pharmaceuticals takes place in low-cost production countries like India and China. Recent reports from India demonstrate that such production sites may emit very large quantities of e.g. antibiotics, yielding levels of the drugs in local surface waters higher than those found in the blood of patients under treatment. The major route for pharmaceutical residues to reach the aquatic environment is most probably by excretion from patients undergoing pharma treatment. Since many pharmaceutical substances are not metabolized in the body they may be excreted in biologically active form, usually via the urine. Furthermore, many pharmaceutical substances are not fully taken up from the intestine (following oral administration in patients) into their blood stream. The fraction not taken up into the blood stream will remain in the gut and eventually be excreted via the faeces. Hence, both urine and faeces from treated patients contain pharmaceutical residues. Between 30 and 90% of the orally administered dose is generally excreted as active substance in the urine. An additional source to environmental pollution with pharmaceuticals is improper disposal of unused or expired drug residues. In European countries take-back systems for such residues are usually in place (although not always utilized to full extent) while in e.g. the US only voluntary initiatives on a local basis exist | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Though most of the waste goes to incineration and people are asked to throw unused or expired pharmaceuticals into the household waste investigations in Germany showed that up to 24% of liquid pharmaceuticals and 7% of tablets or ointments are disposed always or at least “rarely” via the toilet or sink. Proper destruction of pharma residues should yield rest products without any pharmaceutical or ecotoxic activity. Furthermore, the residues should not act as components in the environmental formation of new such products. Incineration at a high temperature (>1000 degrees Celsius) is considered to fulfill the requirements, but even following such incineration residual ashes from the incineration should be properly taken care of. Pharmaceuticals used in veterinary medicine, or as additives to animal food, pose a different problem, since they are excreted into soil or possibly open surface waters. It is well known that such excretions may affect terrestrial organisms directly, leading to extinction of exposed species (e.g. dung-beetles). Lipid-soluble pharma residues from veterinary use may bind strongly to soil particles, with little tendency to leak out to ground water or to local surface waters. More water-soluble residues may be washed out with rain or melting snow and reach both ground water and surface water streams. The use of pharmaceuticals and personal care products (PPCPs) is on the rise with an estimated increase from 2 billion to 3 | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products 9 billion annual prescriptions between 1999 and 2009 in the United States alone. PPCPs enter into the environment through individual human activity and as residues from manufacturing, agribusiness, veterinary use, and hospital and community use. In Europe, the input of pharmaceutical residues via domestic waste water is estimated to be around 80% whereas 20% is coming from hospitals. Individuals may add PPCPs to the environment through waste excretion and bathing as well as by directly disposing of unused medications to septic tanks, sewers, or trash. Because PPCPs tend to dissolve relatively easily and do not evaporate at normal temperatures, they often end up in soil and water bodies. Some PPCPs are broken down or processed easily by a human or animal body and/or degrade quickly in the environment . However, others do not break down or degrade easily. The likelihood or ease with which an individual substance will break down depends on its chemical makeup and the metabolic pathway of the compound. A 2002 study by the U.S. Geological Survey found detectable quantities of one or more chemicals in 80 percent of a sampling of 139 susceptible streams in 30 states. The most common pharmaceuticals detected were nonprescription drugs; detergents, fire retardants, pesticides, natural and synthetic hormones, and an assortment of antibiotics and prescription medications were also found | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products A 2006 study found detectable concentrations of 28 pharmaceutical compounds in sewage treatment plant effluents, surface water, and sediment. The therapeutic classes included antibiotics, analgesics and anti-inflammatories, lipid regulators, beta-blockers, anti-convulsant, and steroid hormones. Although most chemical concentrations were detected at low levels (nano-grams/Liter (ng/L)), there are uncertainties that remain regarding the levels at which toxicity occurs and the risks of bioaccumulation of these pharmaceutical compounds. A study published in late 2014 reported a spike in the levels of ecstasy, ketamine, caffeine and acetaminophen in nearby rivers coinciding with a Taiwanese youth event attended by around 600,000 people. In 2018, shellfish in Puget Sound, waters that receive treated sewage from the Seattle area, tested positive for oxycodone. Besides the identified input from human medicine there appears diffuse pollution for example from pharmaceuticals used in agriculture, too. Investigations in Germany, France and Scotland showed traces of PPCPs upstream of waste water treatment plant effluents to rivers, too. The scope of human exposure to pharmaceuticals and personal care products from the environment is a complex function of many factors | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products These factors include the concentrations, types, and distribution of pharmaceuticals in the environment; the pharmacokinetics of each drug; the structural transformation of the chemical compounds either through metabolism or natural degradation processes; and the potential bioaccumulation of the drugs. More research is needed to determine the effects on humans of long-term exposure to low levels of PPCPs. The full effects of mixtures of low concentrations of different PPCPs is also unknown. "The U.S. EPA risk assessment states that the acceptable daily intake (ADI) of pharmaceuticals is around 0.0027 mg/kg‐day." Due to the lack of research of toxicity guidelines and their effects on human health it is difficult to determine a healthy dosage for water contaminated by pharmaceuticals. "The pharmaceutical sample size tested does not give a full representation of human exposure. Only 17 out of 3000 prescriptions are screened for in drinking water." In addition, “The EPA and FDA regulations state that a drug or chemical is not considered harmful until clear evidence shows that a substance causes harm". This means that we are not testing or screening for thousands of contaminants in our drinking water. Health risk assessments have not been conducted to provide concrete evidence to link pharmaceutical contamination and adverse human health effects. "However adverse health outcomes are displayed in aquatic organisms. Fish living near water treatment plants have been reported to be feminized | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products " "Some male fish started to develop ovaries and other feminized characteristic due to pharmaceutical pollution some species have decreased in population due to exposure of EE2 and other hormonal ECD substances." Although research has shown that PPCPs are present in water bodies throughout the world, no studies have shown a direct effect on human health. However, the absence of empirical data cannot rule out the possibility of adverse outcomes due to interactions or long-term exposures to these substances. Because the amounts of these chemicals in the water supply may be in the parts per trillion or parts per billion, it is difficult to chemically determine the exact amounts present. Many studies have therefore been focused to determining if the concentrations of these pharmaceuticals exist at or above the accepted daily intake (ADI) at which the designed biological outcomes can occur. In addition to the growing concerns about human health risks from pharmaceutical drugs via environmental exposures, many researchers have speculated about the potential for inducing an antibiotic resistance. One study found 10 different antibiotics in sewage treatment effluents, surface water, and sediments. Some microbiologists believe that if antibiotic concentrations are higher than the minimum inhibitory concentrations (MICs) of a species of pathogenic bacteria, a selective pressure would be exerted and, as a result, antibiotic resistance would be selectively promoted | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products It has also been proven that at even sub-inhibitory concentrations (e.g., one-fourth of the MIC), several antibiotics are able to have an effect on gene expression (e.g., as shown for the modulation of expression of toxin-encoding genes in Staphylococcus aureus). For reference the MIC of erythromycin that is effective against 90 percent of lab grown Campylobacter bacteria, the most common food-borne pathogen in the United States, is 60 ng/mL. One study found that the average concentration of erythromycin, a commonly prescribed antibiotic, was 0.09 ng/mL in water treatment plant effluents. Additionally, transfer of genetic elements among bacteria has been observed under natural conditions in wastewater treatment plants, and selection of resistant bacteria has been documented in sewers receiving wastewaters from pharmaceutical plants. Moreover, antibiotic resistant bacteria may also remain in sewage sludge and enter the food chain if the sludge is not incinerated but used as fertilizer on agricultural land. The relationship between risk perception and behavior is multifaceted. Risk management is most effective once the motivation behind the behavior of disposing unused pharmaceuticals is understood. There was little correlation found between the perception of risk and knowledge regarding pharmaceutical waste according to a study conducted by Cook and Bellis in 2001 | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products This study cautioned against the effectiveness of attempting to change the public’s behavior on these health issues by warning them of the risks associated with their actions. It is advised to take careful measures to inform the public in a way that does not impart guilt but rather public awareness. For example, a study carried out by Norlund and Garvill in Sweden (2003) that found that some people may make a personal sacrifice in terms of comfort because they feel that it would be helpful to reduce further environmental damage caused by the use of cars. Awareness of air pollution problems was a factor in their decision to take action on a more environmentally favorable choice of transportation. Thus, the goal of Bound’s project encapsulates whether the perception of risk associated with pharmaceuticals has an effect on the way in which medication is commonly disposed. In order to conduct this study, the pharmaceuticals were grouped by their therapeutic action in order to help participants identify them. The eight therapeutic groups are listed below: antibacterials, antidepressants, antihistamines, antiepileptics, hormone treatments, and lipid regulators. Next, a survey was created to examine the disposal patterns of the participants and their perception of the existing risk or threat against the environment. Respondents were asked the following questions in part one of the survey: 1. When and how they disposed of pharmaceuticals. 2. How they perceive the risk to the environment posed by pharmaceuticals. 3 | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products To differentiate between the risks associated with different classed of pharmaceuticals. Part two of the survey involved each of the eight pharmaceutical groups described above individually. Finally, the third part asked information about the age, sex, profession, postcode, and education of participants. The sample size of participants was precise in comparison to the actual distribution of males and females in the UK: Sample- 54.8 percent were female and 45.2 percent male vs. Actual- the UK of 51.3 percent female to 48.7 percent male. Results showed that when a medication must be discarded, 63.2 percent of participants throw them in a bin, 21.8 percent return them to a pharmacist, and 11.5 percent dispose of them via the toilet/sink, while the remaining 3.5 percent keep them. Only half of the respondents felt like pharmaceuticals could potentially be harmful to the environment. Upon examination of factors relevant to risk perception, there was no definite link found between perception and education or income. Dr. Bound noted that participation in altruistic activities such as Environmental Conservation groups may provide members with the ability to better grasp the effects of their actions in the environment. In regards to the aquatic environment, it is hard for one to perceive the favorable effects of properly disposing medication. There also exists the plausibility that a person’s behavior will only be affected if there is a severe risk to themselves or humans as opposed to an environmental threat | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Even though there are serious threats of pharmaceutical pollution resulting in the feminization of certain fish, they have a lower priority because they are not easily understood or experienced by the general public. In Jonathan P. Bound’s opinion, the provision of information about exactly how to go about disposing unused medication properly in conjunction with risk education may have a more positive and forceful effect. Several recommendations and initiatives have been made to prevent pharmaceutical pollution in the environment. Important practices include: First, it is imperative that patients become educated on pharmaceutical pollution and its hazardous effects on humans, animals, and the overall environment. By educating patients on proper disposal of unused drugs, steps are being taken to further prevent pharmaceutical waste in the environment. Consumers should take precautions before tossing out drugs in the trash or flushing them down the toilet. Community take-back programs have been set up for consumers to bring back unused drugs for proper disposal. Another initiative is for pharmacies to serve as a take-back site for proper drug disposal such as implementing recycling bins for customers to bring back unused or expired medicines while they’re shopping. In addition, medical foundations could receive these medicines to administer them to people who need them, while destroying those that are in excess or expired | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Furthermore, educating physicians and patients on the importance of proper drug disposal and the environmental concern will help further reduce pharmaceutical waste. Also, implementing initiatives for hospitals to focus on better practices for hazardous waste disposal may prove to be beneficial. The US EPA encourages hospitals to develop efficient pharmaceutical disposal practices by giving them grants. This incentive may be very beneficial to other hospitals worldwide. Additionally, “It is critical for us to develop an analytical method of identifying, testing, and regulating the amount of pharmaceuticals in the water systems”. Data must be collected in order to accurately measure the prevalence of pharmaceuticals in drinking water. “Multiple Health risk assessments should be conducted to understand the effects of prolonged exposure to pharmaceuticals in drinking water”. Community-based programs should be developed to monitor exposure and health outcomes. We should encourage the pharmaceutical industry to develop technology that extracts pharmaceuticals from waterways. “Extensive research must be conducted to determine the amount of pharmaceutical contamination in the environment and its effects on animals and marine life”. We must remember that many pharmaceuticals pass through the human body unchanged, so it is best for human excrement to not go into waterways, even after conventional treatment, which can also not remove these chemicals | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products It is therefore preferable for human feces and urine to go into fertile soil, where they will receive more effective treatment by numerous microbes found there, over longer amounts of time, and stay away from waterways, via the use of Urine-diverting Dry Toilets, Composting Toilets, and ArborLoos. As mentioned below, constructed wetlands are efficient at removing these chemicals, but it is better for them to not go into water in the first place. While the full effects of most PPCPs on the environment are not understood, there is concern about the potential they have for harm because they may act unpredictably when mixed with other chemicals from the environment or concentrate in the food chain. Additionally, some PPCPs are active at very low concentrations, and are often released continuously in large or widespread quantities. Because of the high solubility of most PPCPs, aquatic organisms are especially vulnerable to their effects. Researchers have found that a class of antidepressants may be found in frogs and can significantly slow their development. The increased presence of estrogen and other synthetic hormones in waste water due to birth control and hormonal therapies has been linked to increased feminization of exposed fish and other aquatic organisms. The chemicals within these PPCP products could either affect the feminization or masculinization of different fishes, therefore affecting their reproductive rates | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products In addition to being found only in waterways, the ingredients of some PPCPs can also be found in the soil. Since some of these substances take a long time or cannot be degraded biologically, they make their way up the food chain. Information pertaining to the transport and fate of these hormones and their metabolites in dairy waste disposal is still being investigated, yet research suggest that the land application of solid wastes is likely linked with more hormone contamination problems. Not only does the pollution from PPCPs affect marine ecosystems, but also those habitats that depend on this polluted water. There are various concerns about the effects of pharmaceuticals found in surface waters and specifically the threats against rainbow trout exposed to treated sewage effluents. Analysis of these pharmaceuticals in the blood plasma of fish compared to human therapeutic plasma levels have yielded vital information providing a means of assessing risk associated with medication waste in water. In a study by Dr. Jerker Fick from Umeå University rainbow trout were exposed to undiluted, treated sewage water at three different sits in Sweden. They were exposed for a total of 14 days while 25 pharmaceuticals were measured in the blood plasma at different levels for analysis. The progestin Levonorgestrel was detected in fish blood plasma at concentrations between 8.5 and 12 ng mL-1 which exceed the human therapeutic plasma level | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Studies show that the measured effluent level of Levonorgestrel in the three areas was shown to reduce the fertility of the rainbow trout. The three sites chosen for field exposures were in located in Stockholm, Gothenburg, and Umeå. They were chosen according to their varying degrees of treatment technologies, geographic locations, and size. The effluent treatment includes active sludge treatment, nitrogen and phosphorus removal (except in Umeå), primary clarification, and secondary clarification. Juvenile rainbow trout were procured from Antens fiskodling AB, Sweden and Umlax AB, Sweden. The fish were exposed to aerated, undiluted, treated effluent. Since all of the sites underwent sludge treatment, it can be inferred that they are not representative of the low end of treatment efficacy. Of the 21 pharmaceuticals that were detected in the water samples, 18 were identified in the effluent, 17 in the plasma portion, and 14 pharmaceuticals were found in both effluent and plasma. Starting in the mid-1960s, ecologists and toxicologists began to express concern about the potential adverse effects of pharmaceuticals in the water supply, but it wasn’t until a decade later that the presence of pharmaceuticals in water was well documented. Studies in 1975 and 1977 found clofibric acid and salicylic acids at trace concentrations in treated water. Widespread concern about and research into the effect of PPCPs largely started in the early 1990s | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Until this time, PPCPs were largely ignored because of their relative solubility and containment in waterways compared to more familiar pollutants like agrochemicals, industrial chemicals, and industrial waste and byproducts. Since then, a great deal of attention has been directed to the ecological and physiological risk associated with pharmaceutical compounds and their metabolites in water and the environment. In the last decade, most research in this area has focused on steroid hormones and antibiotics. There is concern that steroid hormones may act as endocrine disruptors. Some research suggests that concentrations of ethinylestradiol, an estrogen used in oral contraceptive medications and one of the most commonly prescribed pharmaceuticals, can cause endocrine disruption in aquatic and amphibian wildlife in concentrations as low as 1 ng/L. Current research on PPCPs aims to answer these questions: Pharmacoenvironmentology is an extension of pharmacovigilance as it deals specifically with the environmental and ecological effects of drugs given at therapeutic doses. Pharmacologists with this particular expertise (known as a pharmacoenvironmentologist) become a necessary component of any team assessing different aspects of drug safety in the environment. We must look at the effects of drugs not only in medical practice, but also at its environmental effects. Any good clinical trial should look at the impact of particular drugs on the environment | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Things we need to address in pharmacoenvironmentology are drugs and their exact concentration in different parts of the environment. Pharmacoenvironmentology is a specific domain of pharmacology and not of environmental studies. This is because it deals with drugs entering through living organisms through elimination. Pharmacovigilance is a new branch of science, which was born in 1960 after the incidence of the thalidomide disaster. Thalidomide is a teratogen and caused horrific birth abnormalities. The thalidomide disaster lead to the present day approach to drug safety and adverse event reporting. According to the EPA, pharamacovigilance is science aiming to capture any adverse effects of pharmaceuticals in humans after use. However, ecopharmacovigilance is the science, and activities concerning detection, assessment, understanding, and prevention of adverse effects of pharmaceuticals in the environment which affect humans and other animal species. There has been a growing focus among scientists about the impact of drugs on the environment. In recent years, we have been able to see human pharmaceuticals that are being detected in the environment which most are typically found on surface water. The importance of ecopharmacovigilance is to monitor adverse effects of pharmaceuticals on humans through environmental exposure | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Due to this relatively new field of science, researchers are continuously developing and understanding the impacts of pharmaceuticals in the environment and its risk on human and animal exposure. Environmental risk assessment is a regulatory requirement in the launch of any new drug. This precaution has become a necessary step towards the understanding and prevention of adverse effects of pharmaceutical residue in the environment. It is important to note that pharmaceuticals enter the environment from the excretion of drugs after human use, hospitals, and improper disposal of unused drugs from patients. Ecopharmacology concerns the entry of chemicals or drugs into the environment through any route and at any concentration disturbing the balance of ecology (ecosystem), as a consequence. Ecopharmacology is a broad term that includes studies of “PPCPs” irrespective of doses and route of entry into environment. The geology of a karst aquifer area assists with the movement of PPCPs from the surface to the ground water. Relatively soluble bedrock creates sinkholes, caves and sinking streams into which surface water easily flows, with minimal filtering. Since 25% of the population get their drinking water from karst aquifers, this affects a large number of people. A 2016 study of karst aquifers in southwest Illinois found that 89% of water samples had one or more PPCP measured | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Triclocarban (an antimicrobial) was the most frequently detected PPCP, with gemfibrozil (a cardiovascular drug) the second most frequently detected. Other PPCPs detected were trimethoprim, naproxen, carbamazepine, caffeine, sulfamethoxazole, and fluoxetine. The data suggests that septic tank effluent is a probable source of PPCPs. Sewage treatment plants (STP) work with physical, chemical, and biological processes to remove nutrients and contaminants from waste water. Usually the STP is equipped with an initial mechanical separation of solid particles (cotton buds, cloth, hygiene articles etc.) appearing in the incoming water. Following this there may be filters separating finer particles either occurring in the incoming water or developing as a consequence of chemical treatment of the water with flocculating agents. Many STPs also include one or several steps of biological treatment. By stimulating the activity of various strains of microorganisms physically their activity may be promoted to degrade the organic content of the sewage by up to 90% or more. In certain cases more advanced techniques are used as well. The today most commonly used advanced treatment steps especially in terms of micropollutants are PPCPs are difficult to remove from wastewater with conventional methods. Some research shows the concentration of such substances is even higher in water leaving the plant than water entering the plant | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products Many factors including environmental pH, seasonal variation, and biological properties affect the ability of a STP to remove PPCPs. A 2013 study of a drinking water treatment plant, found that of 30 PPCPs measured at both the source water and the drinking water locations, 76% of PPCPs were removed, on average, in the water treatment plant. Ozonation was found to be an efficient treatment process for the removal of many PPCPs. However, there are some PPCPs that were not removed, such as DEET used as mosquito spray, nonylphenol which is a surfactant used in detergents, the antibiotic erythromycin, and the herbicide atrazine. Several research projects are running to optimize the use of advanced sewage treatment techniques under different conditions. The advanced techniques will increase the costs for the sewage treatment substantially. In a European cooperation project between 2008 and 2012 in comparison 4 hospital waste water treatment facilities were developed in Switzerland, Germany, The Netherlands and Luxembourg to investigate the elimination rates of concentrated waste water with pharmaceutical “cocktails” by using different and combined advanced treatment technologies. Especially the German STP at Marienhospital Gelsenkirchen showed the effects of a combination of membranes, ozone, powdered activated carbon and sand filtration. But even a maximum of installed technologies could not eliminate 100% of all substances and especially radiocontrast agents are nearly impossible to eliminate | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products The investigations showed that depending on the installed technologies the treatment costs for such a hospital treatment facility may be up to 5.50 € per m. Other studies and comparisons expect the treatment costs to increase up to 10%, mainly due to energy demand. It is therefore important to define best available technique before extensive infrastructure investments are introduced on a wide basis. The fate of incoming pharmaceutical residues in the STP is unpredictable. Some substances seem to be more or less completely eliminated, while others pass the different steps in the STP unaffected. There is no systematic knowledge at hand to predict how and why this happens. Pharmaceutical residues that have been conjugated (bound to a bile acid) before being excreted from the patients may undergo de-conjugation in the STP, yielding higher levels of free pharmaceutical substance in the outlet from the STP than in its incoming water. Some pharmaceuticals with large sales volumes have not been detected in the incoming water to the STP, indicating that complete metabolism and degradation must have occurred already in the patient or during the transport of sewage from the household to the STP. In the United States, “There are no federal regulations limiting the levels of pharmaceuticals in wastewater or drinking water”, according to EPA. Three birth controls substances and one antibiotic were added to the pharmaceuticals contaminant candidate list (CCL 3) | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products EPA states that they are 8 pharmaceuticals that are classified as hazardous waste. Out of 3000 pharmaceuticals EPA has only evaluated 100 of them leaving numerous of unscreened compounds in the water.” In 2008, EPA proposed an amendment to the Universal Waste Rule to address pharmaceutical wastes.” However, no action on the Rule has occurred since the hearing in the U.S. senate in 2009”. The Clean Water Act (CWA), Safe Drinking Water Act (SDWA), and the Universal Waste Regulations under the Resource Conservation and Recovery Act (RCRA) do little to protect the American population from pharmaceutical contamination in waterways. The EPA has the ability to implement governmental regulations to insure that the public has access to water that is free of pharmaceutical pollution however, no laws have been enacted even though “ the U.S. Government Accountability Office (GAO) reports that some research has demonstrated potential impact on human health from exposure to pharmaceuticals found in drinking water, such as antibiotics and EE2 substances that interfere with human hormone development”. The EPA and other governmental agencies are not focused on this issue. They are not demanding any changes or regulations for Pharmaceutical pollution. They did not review the 3000 Pharmaceutical substances to determine their effect on human health. There are no long term studies or health assessments created to examine how this affects us or the environment | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products In 2019, the US Virgin Islands banned coral damaging sunscreens, in a growing trend to try to protect coral reefs. 80% of pills in the world are packed with blister packaging, which is the most convenient type for several reasons. Blister packs have two main components, the “lid” and the “blister” (cavity). Lid is mainly manufactured with aluminum (Al) and paper. The Cavity consists of polyvinyl chloride (PVC), polypropylene (PP), polyester (PET) or aluminum (Al). If users employ proper disposal methods, all these materials can be recycled and the harmful effects to the environment can be minimized. However, a problem arises with the improper disposal either by burning or disposing as normal household waste. Burning of blister packs directly causes air pollution by the combustion products of polypropylene ([CH]), polyester ([CHO]), and polyvinyl chloride ([CHCHCl]). The combustion reactions and products of these chemicals are mentioned below. [CH] + 9n/2 O → 3n CO +3n HO [CHO] + 10n O → 10n CO +4n HO [CHCHCl] + 2n O → n CO + n HO + n HCl + n CO Even though polypropylene and polyester is harmful to the environment, the most toxic effect is due to the combustion of polyvinyl chloride since it produces hydrochloric acid (HCl) which is an irritant in the lower and upper respiratory tract that can cause adverse effects to human beings | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products The disposal of blister packs as normal waste, will forbid recycling process and eventually accumulate in soil or water, which will result soil and water pollution since bio-degradation processes of compounds like PVC, PP and PET are very slow. As a result, ecologically damaging effects like disturbances of the habitats and movements can be seen. Ingestion by the animals, affect the secretion of gastric enzymes and steroid hormones that can decrease the feeding stimuli and may also cause problems in reproduction. At low pH, aluminum can increase its solubility according to the following equation. As a result, the negative effects of both aquatic and terrestrial ecosystems can be generated. 2Al+ 6H → 2Al + 3H By employing proper disposal methods, all manufacturing materials of blister packs like PP, PE, PVC and Al can be recycled and the adverse effects to the environment can be minimized. Even though, the synthesis of these polymers relatively simple, the recycling process can be very complex since the blister packs contain metals and polymers together. As the first step of recycling, separation of Al and Polymers using the hydrometallurgical method which uses hydrochloric acid (HCl) can be incorporated. Then PVC can be recycled by using mechanical or chemical methods | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products The most recent trend is to use biodegradable, eco-friendly “bio plastics” which are also called as biopolymers such as derivatives of starch, cellulose, protein, chitin and xylan for pharmaceutical packaging, to reduce the hostile effects to the environment. Nail polish remover has the ability to enter bodies of water and soil after entering landfills or by precipitation, such as rain or snow. However, due to acetone's high volatility, most of it that enters the bodies of water and soil will evaporate again and re-enter the atmosphere. Not all of the acetone molecules will evaporate again, and so, when acetone remains in the bodies of water or soil, a reaction will occur. Nail polish remover evaporates easily because acetone's intermolecular forces are weak. An acetone molecule can't attract other acetone molecules easily because its hydrogens are not slightly positive. The only force that holds acetone molecules together is its permanent dipoles which are weaker than hydrogen bonds. Since nail polish remover is a solvent, it will dissolve in water. When acetone dissolves in water, it hydrogen bonds with water. The more nail polish remover that enters the hydrosphere will increase the concentration of acetone and then increase the concentration of the solution created when acetone and water bonds. If enough nail polish remover is disposed, it can reach the lethal dose level for aquatic life. Nail polish remover can also enter the lithosphere by landfills and by precipitation | https://en.wikipedia.org/wiki?curid=22037708 |
Environmental impact of pharmaceuticals and personal care products However, it will not bind to the soil. Microorganisms in the soil will decompose acetone. The consequence of microorganisms decomposing acetone is the risk it has to cause oxygen depletion in bodies of water. The more acetone readily available for microorganism decomposition leads to more microorganisms reproduced and thus oxygen depletion because more microorganisms use up the available oxygen. When nail polish remover evaporates, acetone enters the atmosphere in the gaseous phase. In the gaseous phase, acetone can undergo photolysis and breakdown into carbon monoxide, methane, and ethane. When temperatures are between 100 - 350 degrees Celsius, the following mechanism occurs: (CH)2CO + hv → CH + CHCO CHCO → CH+ CO CH+ (CH)2CO → CH4 + CH2COCH 2CH → C2H6 A second pathway that nail polish remover can enter in the atmosphere is reacting with hydroxyl radicals. When acetone reacts with hydroxyl radicals, its main product is methylglyoxal. Methylglyoxal is an organic compound that is a by-product of many metabolic pathways. It is an intermediate precursor for many advanced glycation end-products, that are formed for diseases such as diabetes or neurodegenerative diseases. The following reaction occurs: (CH)2CO + ·OH → CHC(O)OH + ·CH CHC(O)OH + ·CH→ CHC(O)COH + 3H+ Sunscreens use a variety of chemical compounds to prevent UV radiation, like benzophenone, octocrylene, octinoxate, among others. These chemical compounds affect the life of coral reefs in different stages of their life and contributes to coral bleaching. | https://en.wikipedia.org/wiki?curid=22037708 |
Plug (sanitation) A plug in sanitation is an object that is used to close a drainage outlet firmly. The insertion of a plug into a drainage outlet allows the container to be filled with water or other fluids. In contrast to screw on caps, plugs are pushed into the hole and are not put over the hole. Plugs are most commonly encountered in the bathroom or kitchen, for use in bathtubs, wash basins or sinks. Typically plugs are made from a soft material, such as rubber, or have a soft outer rim, so that they can be fitted to holes slightly smaller than their diameter; this ensures a tight seal. They are often connected by a ball chain which ensures the plug may be pulled from the drain with relative ease. Some modern plugholes dispense with the need for a separate plug, having instead a built-in 'pop-up plug' operated by a handle on the sink, that can move up or down to open or close the plughole. | https://en.wikipedia.org/wiki?curid=22038253 |
Alkali–carbonate reaction The alkali–carbonate reaction is an alteration process first suspected in the 1950's in Canada for the degradation of concrete containing dolomite aggregates. Alkali from the cement might react with the dolomite crystals present in the aggregate inducing the production of brucite, (MgOH), and calcite (CaCO). This mechanism was tentatively proposed by Swenson and Gillott (1964) and may be written as follows: Brucite (Mg(OH)), could be responsible for the volumetric expansion after de-dolomitisation of the aggregates, due to absorption of water. The alkali–carbonate reaction is also catalyzed by the soluble NaOH produced by the reaction of with (portlandite) present in the hardened cement paste (HCP), therefore perpetuating the reaction indefinitely as observed by Fournier and Bérubé (2000) and Bérubé "et al." (2005). The sum of the two above mentioned reactions leading to the ultimate production of brucite and calcium carbonate can be written as follows: The alkali-carbonate reaction is much less understood than the alkali-silica reaction. Both reactions share in common the continuous regeneration of the sodium hydroxide (NaOH) after the reaction of soluble sodium carbonate or sodium silicate with calcium hydroxide, . However, impure dolomitic aggregates also often contain clay impurities, and small amounts of pyrite () and organic matter. The alkali-carbonate reaction could therefore also simply hide an alkali-silica or an alkali-silicate reaction | https://en.wikipedia.org/wiki?curid=22042208 |
Alkali–carbonate reaction Anyway a chemical coupling between ACR and ASR cannot be ruled out. | https://en.wikipedia.org/wiki?curid=22042208 |
Praseodymium oxide may refer to: | https://en.wikipedia.org/wiki?curid=22044327 |
Novodur Lustran and are trade names for various types of styrenic resins (ABS, ASA, SMA) owned by INEOS Styrolution, which is part of INEOS. These resins are used mainly for housings and covers requiring good toughness, strength, stiffness, chemical resistance and a good to very good surface finish. In addition to the general-purpose injection molding grades, the range comprises a large number of high heat resistant grades as well as special-purpose products for extrusion and chemical electroplating. Glass fiber reinforced and flame retardant grades are also available. | https://en.wikipedia.org/wiki?curid=22046610 |
Vacuum ceramic filter A vacuum ceramic filter is designed to separate liquids from solids for dewatering purposes. The device consists of a rotator, slurry tank, ceramic filter plate, distributor, discharge scraper, cleaning device, frame, agitating device, pipe system, vacuum system, automatic acid dosing system, automatic lubricating system, valve and discharge chute. The operation and construction principle of vacuum ceramic filter resemble those of a conventional disc filter, but the filter medium is replaced by a finely porous ceramic disc. The disc material is inert, has a long operational life and is resistant to almost all chemicals. Performance can be optimized by taking into account all those factors which affect the overall efficiency of the separation process. Some of the variables affecting the performance of a vacuum ceramic filter include the solid concentration, speed rotation of the disc, slurry level in the feed basin, temperature of the feed slurry, and the pressure during dewatering stages and filter cake formation. Vacuum ceramic filters are to be found in the following industries: The process is used during a large continuous process of separating free filtering suspensions where washing is not required. Basically the filter works to separates solid-liquid mixtures by removing the water from mineral concentrates and moulding the feed slurries into pellets. This is accomplished by capillary action under low vacuum pressure | https://en.wikipedia.org/wiki?curid=22046679 |
Vacuum ceramic filter The pelletizing of the slurries is done by adding some solid matter to the sewage sludge so that water can be easily removed from the mixture. Eventually, the final cake products contain very little moisture and can be deposited as sewage. This process is commonly followed by bleaching and heating the cake. The end product of this filtration is a dry cake and filtrate containing no solid product. The main advantage over other filtration systems is the reduction in energy consumption, up to 90% because no air flows through the discs due to the use of capillary force acting on the pores. Air breakthrough is prevented by the fine pores of the filter, thus allowing retention of higher vacuum levels. Therefore, the vacuum losses are less, which means the vacuum pump required is smaller than in conventional disc filters, thus minimizing operating costs. Power consumed by a vacuum ceramic filter with 45 m of filtration area is 15 kW while 170 kW is consumed by similar filters with cloth membranes. Generally, conventional disc filters are not suitable for cake washing because the water quickly runs off the surface of the cake. As the cake solids are sprayed with a wash liquid to remove impurities, they are not suitable for conventional filtration systems where channelling or uneven distribution occurs, leading to cake cracking. However, cake washing has been proved to be more efficient with vacuum ceramic filters due to the steady flow profile and the even distribution of the cake | https://en.wikipedia.org/wiki?curid=22046679 |
Vacuum ceramic filter A further advantage of vacuum ceramic filter is the high output capacity with a very low water content and drier filter cake. By comparison, the performance of a VDFK-3 ceramic filter was compared with the existing BOU-40 and BLN40-3 drum type vacuum filters to filter aluminium hydroxide. From the results, the average moisture content was 5% lower when a vacuum ceramic filter was used. Vacuum ceramic filters also have a longer service life while cloth filters have to be replaced, which eventually increases the moisture content of the cake, lowers the productivity and disturbs the production operations. In addition, the ceramic filter is both mechanically and chemically reliable enough to withstand regeneration. Whilst the vacuum ceramic filter has proved to be a great innovation, there are still some limitations involved when operating the equipment. Ceramic filters exhibit large fluctuations in the recoiling washing pressure (0.05~0.35 MPa). This raises the short-term negative pressure and induces dilute acid due to the falling suck phenomenon. Therefore, the cleaning effect of the ceramic plates and the efficiency of the filter will be negatively affected. There are many design criteria which vary according to the type of disc and the required filtering capacity. The typical filter for extracting iron contains 12 ceramic filtering plates of the filtering elements (discs), which have a diameter of about 2705 mm, making the total filter surface 120 m | https://en.wikipedia.org/wiki?curid=22046679 |
Vacuum ceramic filter This filter is most suited to filter feed slurries with high solid concentrations (5-20% w/w) and particles ranging in size from 1–700 µm. The area of the filters available in the ceramic filter is up to 45 m, making them useful for metal and mineral concentrate processing. The ceramic discs are available in two types, cast plate and membrane plate. The cast plate is a one piece ceramic plate with a homogeneous surface and a granulated core. The filter medium of the cast plate is the thick walls, separated by ceramic granules. These features form a rigid mechanical structure. The membrane plate type contains a thin membrane over a coarser core and a multi-layer porous structure made of aluminium oxide. The coarse part of the equipment provides mechanical strength to its structure while the intermediate layer acts as a membrane carrier. The outer layer membrane acts as a filtering layer. The filtration layer of the ceramic filter has uniform pores, which means that only a certain size of particles can be filtered by using vacuum ceramic filters. There are at least three stages involve in the operation of a vacuum disc filter: Stage 1: Cake formation The discs rotate in a slurry trough, compartmentalized to reduce the volume held in it at any one time, and therefore to reduce the residence time of slurry in the trough. The time available for this stage depends on two factors, the rotation speed of the disc and the height of the slurry level in the basin | https://en.wikipedia.org/wiki?curid=22046679 |
Vacuum ceramic filter A vacuum is applied inside the discs to promote cake filtration. Stage 2: Cake dewatering Washing is largely restricted to the upper portions where the cake surface is nearly horizontal in orientation, which occurs at the temperature of the feed. The ceramic filter uses a sintered alumina disc to dewater slurry under low vacuum. The dewatering occurs by drawing water from the slurry by capillary action. This ensures that no air or particles are drawn into the filter medium to cause blockage. However, if too much wash water is applied then it can cascade down the cake and into the feed trough, where it merely dilutes the slurry. Stage 3: Cake drying The final water (moisture) content in the cake is regulated by passing dry (cold or hot) air or gas through the cake. Drying time is dependent on the distribution valve timing, slurry level on the basin, rotation speed, and scraper position. Stage 4: Cake discharge These are the typical conditions for the overall operation of the vacuum ceramic filter: The most important operating parameters of disc filters are the height of the slurry tank, agitation and the intensity and rotation speed of the disc as these will determine the cake formation and drying times. It is important to continuously agitate the slurry in order to prevent sedimentation of the solids. Excessively high agitation intensity may affect cake formation or change the particle size distribution of the product | https://en.wikipedia.org/wiki?curid=22046679 |
Vacuum ceramic filter One of the most commonly used agitators for filtration using vacuum disc filters is an oscillating cradle-type agitator located in the bottom of the basin, which requires fairly high rotation speeds to form homogeneous slurry. For processing rapidly settling high concentration slurries, bottom-feed rotary disc filters are usually used. Stage 1: Filtration The filtrate from the internal passages of the discs is removed by the low vacuum used in the filter, while the small pressure differential across the disc causes cake formation. With a thicker cake produced in this stage, more effective washing is achieved at higher wash liquor flows. However, this causes larger air volumes to be consumed at discharge due to reduced resistance and marginally lower cake moisture. Stage 2: Dewatering In rare cases, due to the even structure of the cakes formed, the steady flow profile of the ceramic filter media and the gas free filtrate flow cake, washing has proved to be efficient in ceramic disc filters. The formation of thicker cakes during filtration and higher vacuum level leads to greater removal of solute. Stage 3: Discharge The basic scraper works well when the cakes are relatively thick and non-sticky. The final cakes are discharged by blade or wire scrapers on either side of the discs However, other types of agitators should be considered and installed if the cake is sticky or thin. An air blow-back system is often employed to aid cake removal where wetter cakes are discharged from disc filter | https://en.wikipedia.org/wiki?curid=22046679 |
Vacuum ceramic filter Filtrate is the waste that has been discharge in vacuum ceramic filters through the waste stream. During cake washing, a wash liquid is sprayed on the cake solids to remove impurities or additional filtrate. The filtrate goes into filtrate tank and is drained through a discharge system. However, the filtrate is recyclable and has low suspended solid content. Thus, it can be recycled through the system without further treatment. Filtrate is used to flush the disc during back flow washing to clean the micro-porous structure and remove any residual cake. One improvement over the standard design of ceramic vacuum filter is to use serialized pore size distributions of non-fibrous porous ceramic filters. The porosity of this type of ceramic can be varied from 20% to 60% by volume, which allows a low-pressure drop of liquid and gas flow. Custom sizes from 1 mm diameter/0.5 mm bore of porous ceramic filters are available for a range of designs. A non-fibrous porous ceramic filter is more resistant in alkaline and acidic conditions compared to fibrous ceramic filters. Thus, it has a longer service life as it has good wearing and erosion resistance as well as being able to withstand high temperatures. Another improvement is applied at the regeneration stage when the residual filter cake is removed by back-flushing the clean plant water to wash the internal ceramic filter. Filter cake dewatering of ceramic filters produces low final cake moistures at minimum operation and maintenance costs | https://en.wikipedia.org/wiki?curid=22046679 |
Vacuum ceramic filter The residuals moisture are removed from the filter cake due to capillary action within the ceramic elements, which rotate above the slurry level. This process gives maximum filtration, and the final cake can be maintained at the lowest moisture content due to the effective cleaning of both ceramic sectors. In addition, performance can be optimized by using an ultrasonic cleaning system to achieve efficient operation conditions for regeneration of plates. The use of filtrate in looped water cycle in the design operation can reduce the water consumption up to 30-50%. High filtrate purity can be obtained, as there is only 0.001-0.005 g/l solids in the filtrate produced from this process. This eventually results in the reduction of polymer flocculant consumption in thickeners. Ceramic scraper knives have been introduced to this design as they are able to shave through the mass formed in filter cake dewatering. The remaining layer of solid residue on the filter provides protection from mechanical abrasion. Therefore, the maintenance costs can be reduced while the service life of the ceramic filter increases. | https://en.wikipedia.org/wiki?curid=22046679 |
122 iron arsenide The unconventional superconductors are part of a new class of iron-based superconductors. They form in the tetragonal I4/mmm, ThCrSi type, crystal structure. The shorthand name "122" comes from their stoichiometry; the 122s have the chemical formula AEFePn, where AE stands for alkaline earth metal (Ca, Ba, Sr or Eu) and Pn is pnictide (As, P, etc.). These materials become superconducting under pressure and also upon doping. The maximum superconducting transition temperature found to date is 38 K in the BaKFeAs. The microscopic description of superconductivity in the 122s is yet unclear. Ever since the discovery of high-temperature (High T) superconductivity in the cuprate materials, scientists have worked tirelessly to understand the microscopic mechanisms responsible for its emergence. To this day, no theory can fully explain the high-temperature superconductivity and unconventional (non-s-wave) pairing state found in these materials. However, the interest of the scientific community in understanding the pairing glue for unconventional superconductors—those in which the glue is electronic, i.e. cannot be attributed to the phonon-induced interactions between electrons responsible for conventional BCS theory s-wave superconductivity—has recently been expanded by the discovery of high temperature superconductivity (up to T = 55 K) in the doped oxypnictide (1111) superconductors with the chemical composition XOFeAs, where X = La, Ce, Pr, Nd, Sm, Gd, Tb, or Dy | https://en.wikipedia.org/wiki?curid=22047573 |
122 iron arsenide The 122s contain the same iron-arsenide planes as the oxypnictides, but are much easier to synthesize in the form of large single crystals. There are two different ways in which superconductivity was achieved in the 122s. One method is the application of pressure to the undoped parent compounds. The second is the introduction of other elements (dopants) into the crystal structure in very specific ratios. There are two doping schemes: The first type of doping involves the introduction of holes into the barium or strontium varieties; hole doping refers to the substitution of one ion for another with fewer electrons. Superconducting transition temperatures as high as 38 K have been reported upon substitution of the 40% of the Ba or Sr ions with K. The second doping method is to directly dope the iron-arsenide layer by replacing iron with cobalt. Superconducting transition temperatures up to ~20 K have been observed in this case. Unlike the oxypnictides, large single crystals of the 122s can be easily synthesized by using the flux method. The behavior of these materials is interesting by that superconductivity exists alongside antiferromagnetism. Various studies including electrical resistivity, magnetic susceptibility, specific heat, NMR, neutron scattering, X-ray diffraction, Mössbauer spectroscopy, and quantum oscillations have been performed for the undoped parent compounds, as well as the superconducting versions | https://en.wikipedia.org/wiki?curid=22047573 |
122 iron arsenide One of the important qualities of the 122s is their ease of synthesis; it is possible to grow large single crystals, up to ~5×5×0.5 mm, using the flux method. In a nutshell, the flux method uses some solvent in which the starting materials for a chemical reaction are able to dissolve and eventually crystallize into the desired compound. Two standard methods show up in the literature, each utilizing a different flux. The first method employs tin, while the second uses the binary metallic compound FeAs (iron arsenide). The 122s form in the I4/mmm tetragonal structure. For example, the tetragonal unit cell of SrFeAs, at room temperature, has lattice parameters a = b = 3.9243 Å and c = 12.3644 Å. The planar geometry is reminiscent of the cuprate high-T superconductors in which the Cu-O layers are believed to support superconductivity. These materials undergo a first-order structural phase transition into the Fmmm orthorhombic structure below some characteristic temperature T that is compound specific. NMR experiments on the CaFeAs show that there is a first-order antiferromagnetic magnetic phase transition at the same temperature; in contrast, the antiferromagnetic transition occurs at a lower temperature in the 1111s. The high temperature magnetic state is paramagnetic, while the low temperature state is an antiferromagnetic state known as a spin-density-wave. Superconductivity has been observed in the 122s up to a current maximum T of 38 K in BaKFeAs with x ≈ 0.4 | https://en.wikipedia.org/wiki?curid=22047573 |
122 iron arsenide Resistivity and magnetic susceptibility measurements have confirmed the bulk nature of the observed superconducting transition. The onset of superconductivity is correlated with the loss of the spin-density-wave state. The T of 38 K in BaKFeAs (x ≈ 0.4) superconductor shows the inverse iron isotope effect. In addition to the iron arsenides, the 122 crystal structure plays an important role for other material systems as well. Three famous examples from the field of heavy fermions are CeCuSi (the "first unconventional superconductor" discovered 1978), URuSi (which is also a heavy fermion superconductor but is the focus of active present research due to the so-called "hidden-order phase" below 17.5 K), and YbRhSi (one of the prime examples of quantum criticality). | https://en.wikipedia.org/wiki?curid=22047573 |
Mechanical alloying (MA) is a solid-state and powder processing technique involving repeated cold welding, fracturing, and re-welding of blended powder particles in a high-energy ball mill to produce a homogeneous material. Originally developed to produce oxide-dispersion strengthened (ODS) nickel- and iron-base superalloys for applications in the aerospace industry, MA has now been shown to be capable of synthesizing a variety of equilibrium and non-equilibrium alloy phases starting from blended elemental or pre-alloyed powders. The non-equilibrium phases synthesized include supersaturated solid solutions, metastable crystalline and quasicrystalline phases, nanostructures, and amorphous alloys. One consideration that should be avoided is powder contamination. is akin to metal powder processing, where metals may be mixed to produce superalloys. occurs in three steps. First, the alloy materials are combined in a ball mill and ground to a fine powder. A hot isostatic pressing (HIP) process is then applied to simultaneously compress and sinter the powder. A final heat treatment stage helps remove existing internal stresses produced during any cold compaction which may have been used. This produces an alloy suitable for high heat turbine blades and aerospace components | https://en.wikipedia.org/wiki?curid=22051259 |
Mechanical alloying Design parameters include type of mill, milling container, milling speed, milling time, type, size, and size distribution of the grinding medium, ball-to-powder weight ratio, extent of filling the vial, milling atmosphere, process control agent, temperature of milling, and the reactivity of the species. The process of mechanical alloying involves the production of a composite powder particles by: During high-energy milling the powder particles are repeatedly flattened, cold welded, fractured and rewelded. Whenever two steel balls collide, some powder is trapped between them. Typically, around 1000 particles with an aggregate weight of about 0.2 mg are trapped during each collision. The force of the impact plastically deforms the powder particles, leading to work hardening and fracture. The new surfaces thus created enable the particles to weld together; this leads to an increase in particle size. Since in the early stages of milling, the particles are soft (if using either ductile-ductile or ductile-brittle material combination), their tendency to weld together and form large particles is high. A broad range of particle sizes develops, with some as large as three times larger than the starting particles. The composite particles at this stage have a characteristic layered structure consisting of various combinations of the starting constituents. With continued deformation particles become work hardened, and fracture by a fatigue failure mechanism and/or by the fragmentation of fragile flakes. 1. Bhadeshia, H. K | https://en.wikipedia.org/wiki?curid=22051259 |
Mechanical alloying D. H. Recrystallisation of practical mechanically alloyed iron-based and nickel-base superalloys, Mater. Sci. Eng. A223, 64-77 (1997) 2. P. R. Soni, Mechanical Alloying: Fundamentals and Applications, Cambridge Int Science Publishing, 2000 - Science - 151 pages. | https://en.wikipedia.org/wiki?curid=22051259 |
Transamidification In organic chemistry, transamidification is the process of exchanging the subunits of a peptide, amide or ester compound with another amine or fatty acid to produce a new amide or peptide. The process has been used for the production of emulsifiers and dispersing agents and oil drilling fluids. | https://en.wikipedia.org/wiki?curid=22052597 |
Anion exchange membrane An anion exchange membrane (AEM) is a semipermeable membrane generally made from ionomers and designed to conduct anions while being impermeable to gases such as oxygen or hydrogen. Anion exchange membranes are used in electrolytic cells and fuel cells to separate reactants present around the two electrodes while transporting the anions essential for the cell operation. An important example is the hydroxide anion exchange membrane used to separate the electrodes of a direct methanol fuel cell (DMFC) or direct-ethanol fuel cell (DEFC). | https://en.wikipedia.org/wiki?curid=22055207 |
Quantum phases are quantum states of matter at zero temperature. Even at zero temperature a quantum-mechanical system has quantum fluctuations and therefore can still support phase transitions. As a physical parameter is varied, quantum fluctuations can drive a phase transition into a different phase of matter. An example of a canonical quantum phase transition is the well-studied Superconductor Insulator Transition in disordered thin films which separates two quantum phases having different symmetries. Quantum magnets provide another example of QPT. The discovery of new quantum phases is a pursuit of many scientists. These phases of matter exhibit properties and symmetries which can potentially be exploited for technological purposes and the benefit of mankind. The difference between these states and classical states of matter is that classically, materials exhibit different phases which ultimately depends on the change in temperature and/or density or some other macroscopic property of the material whereas quantum phases can change in response to a change in a different type of order parameter (which is instead a parameter in the Hamiltonian of the system much unlike the classical case) of the system at zero temperature – temperature does not have to change. The order parameter plays a role in quantum phases analogous to its role in classical phases. Some quantum phases are the result of a superposition of many other quantum phases. | https://en.wikipedia.org/wiki?curid=22056752 |
Cap analysis gene expression (CAGE) is a gene expression technique used in molecular biology to produce a snapshot of the 5′ end of the messenger RNA population in a biological sample (the transcriptome). The small fragments (historically 27 nucleotides long, but now limited only by sequencing technologies) from the very beginnings of mRNAs (5' ends of capped transcripts) are extracted, reverse-transcribed to DNA, PCR amplified and sequenced. CAGE was first published by Hayashizaki, Carninci and co-workers in 2003. CAGE has been extensively used within the FANTOM research projects. The output of CAGE is a set of short nucleotide sequences (often called "tags") with their observed counts. Using a reference genome, a researcher can usually determine, with some confidence, the original mRNA (and therefore which gene) the tag was extracted from. Copy numbers of CAGE tags provide an easy way of digital quantification of the RNA transcript abundances in biological samples. Unlike a similar technique serial analysis of gene expression (SAGE, superSAGE) in which tags come from other parts of transcripts, CAGE is primarily used to locate exact transcription start sites in the genome. This knowledge in turn allows a researcher to investigate promoter structure necessary for gene expression. However, the CAGE protocol has a known bias with a nonspecific guanine (G) at the most 5′ end of the CAGE tags, which is attributed to the template-free 5′-extension during the first-strand cDNA synthesis | https://en.wikipedia.org/wiki?curid=22057524 |
Cap analysis gene expression This would induce erroneous mapping of CAGE tags, for instance to nontranscribed pseudogenes. On the other hand, this addition of Gs was also utilised as a signal to filter more reliable TSS peaks. The original CAGE method (Shiraki "et al.", 2003) was using CAP Trapper for capturing the 5′ ends, oligo-dT primers for synthesizing the cDNAs, the type IIs restriction enzyme MmeI for cleaving the tags, and the Sanger method for sequencing them. Random reverse-transcription primers were introduced in 2006 by Kodzius "et al." to better detect the non-polyadenylated RNAs. In "DeepCAGE" (Valen "et al.", 2008), the tag concatemers were sequenced at a higher throughput on the 454 “"next-generation"” sequencing platform. In 2008, barcode multiplexing was added to the DeepCAGE protocol (Maeda "et al.", 2008). In "nanoCAGE" (Plessy "et al.", 2010), the 5′ ends or RNAs were captured with the template-switching method instead of CAP Trapper, in order to analyze smaller starting amounts of total RNA. Longer tags were cleaved with the type III restriction enzyme EcoP15I and directly sequenced on the Solexa (then Illumina) platform without concatenation. The "CAGEscan" methodology (Plessy "et al.", 2010), where the enzymatic tag cleavage is skipped, and the 5′ cDNAs sequenced paired-end, was introduced in the same article to connect novel promoters to known annotations. With "HeliScopeCAGE" (Kanamori-Katayama "et al | https://en.wikipedia.org/wiki?curid=22057524 |
Cap analysis gene expression ", 2011), the CAP-trapped CAGE protocol was changed to skip the enzymatic tag cleavage and sequence directly the capped 5′ ends on the HeliScope platform, without PCR amplification. It was then automated by Itoh "et al." in 2012. In 2012, the standard CAGE protocol was updated by Takahashi "et al." to cleave tags with EcoP15I and sequence them on the Illumina-Solexa platform. In 2013, Batut "et al." combined CAP trapper, template switching, and 5′-phosphate-dependent exonuclease digestion in "RAMPAGE" to maximize promoter specificity. In 2014, Murata "et al." published the "nAnTi-CAGE" protocol, where capped 5′ ends are sequenced on the Illumina platform with no PCR amplification and no tag cleavage. In 2017, Poulain "et al." updated the "nanoCAGE" protocol to use the "tagmentation" method (based on Tn5 transposition) for multiplexing. In 2018, Cvetesic " et al." increased the sensitivity of CAP-trapped CAGE by introducing selectively degradable carrier RNA (SLIC-CAGE, "Super-Low Input Carrier-CAGE"). | https://en.wikipedia.org/wiki?curid=22057524 |
Orocapital is a goldsmith exhibition, conceived in 1986 by the Consorzio Oro Italia by Giovanni Perrone. The combination of competences and experiences, together with the professionalism of each of its members, enabled the consortium to be become a landmark in the goldsmith’s field, acknowledged for its quality, competence and reliability. The consortium's office is located in Florence. Great attention is paid to the evolution of the goldsmith’s market – both at European and at world level – but, above all, to the Made in Italy promotion. Since 2006, the exhibition has taken place at the Nuova Fiera di Roma: an area which is becoming one of the largest exhibition areas in Europe. | https://en.wikipedia.org/wiki?curid=22061776 |
Supramolecular chirality In chemistry, the term supramolecular chirality is used to describe supramolecular assemblies that are non-superposable on their mirror images. Chirality in supramolecular chemistry implies the non-symmetric arrangement of molecular components in a non-covalent assembly. Chirality may arise in a supramolecular system if one of its component is chiral or if achiral components arrange in a non symmetrical way to produce a supermolecule that is chiral. | https://en.wikipedia.org/wiki?curid=22063516 |
RoGFP The reduction-oxidation sensitive green fluorescent protein (roGFP) is a redox sensitive biosensor. Two cysteines were introduced into the beta barrel structure of the GFP. The oxidation state (reduced dithiol or the oxidized disulfide) of the engineered thiols determines the fluorescence properties of the sensor. Originally, different roGFP versions were presented to allow the "in vivo" imaging of reducing compartments such as the cytosol (roGFP2). The cysteines introduced at the amino acid positions 147 and 204 produced the most robust results. roGFP2 preferentially interacts with glutaredoxins and therefore reports the cellular glutathione redox potential. The specificity of roGFP2 for glutathione is further increased by linking it to the human glutaredoxin 1 (Grx1). By expressing the Grx1-roGFP fusion sensors in the organism of interest and/or targeting the protein to a cellular compartment, it is possible to measure the glutathione redox potential in a specific cellular compartment in real-time and therefore provides major advantages compared to other invasive static methods e.g. HPLC. In addition, roGFPs are used to investigate the topology of ER proteins, or to analyze the ROS production capacity of chemicals. | https://en.wikipedia.org/wiki?curid=22064427 |
Bromatometry is a titration process in which the bromination of a chemical indicator is observed. Potassium bromate alone can be used for the analysis of organoarsenicals | https://en.wikipedia.org/wiki?curid=22064595 |
Nano Today is an international peer-reviewed academic journal dedicated to nanoscience and technology. Established in 2006, it is published six times a year by Elsevier. | https://en.wikipedia.org/wiki?curid=22074782 |
Substrate analog Substrate analogs (substrate state analogues), are chemical compounds with a chemical structure that resemble the substrate molecule in an enzyme-catalyzed chemical reaction. Substrate analogs can act as competitive inhibitors of an enzymatic reaction. An example is phosphoramidate to the "Tetrahymena" group I ribozyme As a competitive inhibitor, substrate analogs occupy the same binding site as its analog, and decrease the intended substrate’s efficiency. The Vmax remains the same while the intended substrate’s affinity is decreased. This means that less of the intended substrate will bind to the enzyme, resulting in less product being formed. In addition, the substrate analog may also be missing chemical components that allow the enzyme to go through with its reaction. This also causes the amount of product created to decrease. Substrate analogs bind to the binding site reversibly. This means that the binding of the substrate analog to the enzyme’s binding site is non-permanent. The effect of the substrate analog can be nullified by increasing the concentration of the originally intended substrate. Other examples of substrate analogs include: 5’-adenylyl-imidodiphosphate: substrate analog of ATP 3-acetylpyridine adenine dinucleotide: substrate analog of NADH Some substrate analogs can still allow the enzyme to synthesize a product despite the enzyme’s inability to metabolize the substrate analog.1 These substrate analogs are known as gratuitous inducers | https://en.wikipedia.org/wiki?curid=22078147 |
Substrate analog Example of a substrate analog that is also a gratuitous inducer: IPTG (isopropyl β-thiogalactoside: substrate analog and gratuitous inducer of β-galactosidase activity There are even substrate analogs that bind to the binding site of an enzyme irreversibly. If this is the case, the substrate analog is called an inhibitory substrate analog, a suicide substrate, or even a Trojan horse substrate. Example of a substrate analog that is also a suicide substrate/Trojan horse substrate: Penicillin: substrate analog and suicide substrate/Trojan horse substrate of peptidoglycan | https://en.wikipedia.org/wiki?curid=22078147 |
1-Hydroxy-7-azabenzotriazole (HOAt) is a triazole used as a peptide coupling reagent. It suppresses the loss of chirality. HOAt has a melting point between 213 and 216 degrees Celsius. As a liquid, it is transparent and without any color. | https://en.wikipedia.org/wiki?curid=22089221 |
Racemic crystallography Racemic protein crystallography is a recently developed technique of structural biology, in which crystals of a protein molecule are grown from a mixture of an ordinary chiral protein molecule and its mirror image; where ordinary protein molecules made of 'left-handed' L-amino acids can be produced in bacteria, yeast, or other cellular expression systems, the mirror image molecule requires chemical synthesis from 'right-handed' D-amino acids. Laura Zawadzke and Jeremy Berg were the first to explore the idea in 1993 using the small (45 amino acid) protein rubredoxin. An early motivation for pursuing such studies was the idea that structure determination might be easier or more robust using diffraction data from a centrosymmetric crystal, which requires growth from a racemic mixture. Aside from this, there is reason to believe that racemic crystallography could have a more profound impact, by dramatically improving the ease with which crystals of protein molecules can be obtained in the laboratory; the protein crystallization problem remains the most challenging and unpredictable obstacle in macromolecular crystallography. In 1995, Stephanie Wukovitz and Todd Yeates, while laying out an explanation for why protein molecules tend strongly to crystallize in certain preferred symmetries, predicted that proteins would crystallize with much greater ease from racemic mixtures owing to the existence of especially favored racemic crystal symmetries that can only be obtained when using a racemic protein mixture | https://en.wikipedia.org/wiki?curid=22098498 |
Racemic crystallography A further prediction was made that a specific crystal symmetry known as P1(bar) would be the dominant space group observed. The invention of native chemical ligation methods by Phil Dawson and Stephen Kent in the mid-1990s opened up prospects for chemically synthesizing larger protein molecules. Kent and co-workers have since tested racemic crystallography on a wide range of protein molecules. Current data (reviewed in ref. provide support for the idea that proteins do crystallize with relative ease from synthetic racemic mixtures (and most often in P1(bar)) as predicted. | https://en.wikipedia.org/wiki?curid=22098498 |
Stannide A stannide can refer to an intermetallic compound containing tin combined with one or more other metals; an anion consisting solely of tin atoms or a compound containing such an anion, or, in the field of organometallic chemistry an ionic compound containing an organotin anion (e.g.see an alternative name for such a compound is stannanide.) When tin is combined with an alkali or alkaline earth metal some of the compounds formed have ionic structures containing monatomic or polyatomic tin anions (Zintl ions), such as Sn in MgSn or in KSn. Even with these metals not all of the compounds formed can be considered to be ionic with localised bonding, for example SrSn, a metallic compound, contains {Sn} square pyramidal units. Ternary (where there is an alkali or alkaline earth metal, a transition metal as well as tin e.g. LiRhSn and MgRuSn) have been investigated. Binary (involving one other metal) and ternary (involving two other metals) intermetallic stannides have been investigated. Niobium stannide, NbSn is perhaps the best known superconducting tin intermetallics. This is more commonly called "niobium-tin". Some examples of stannide Zintl ions are listed below. Some of them contain 2-centre 2-electron bonds (2c-2e), others are "electron deficient" and bonding sometimes can be described using polyhedral skeletal electron pair theory (Wade's rules) where the number of valence electrons contributed by each tin atom is considered to be 2 (the s electrons do not contribute) | https://en.wikipedia.org/wiki?curid=22101239 |
Stannide There are some examples of silicide and plumbide ions with similar structures, for example tetrahedral , the chain anion (Si), and . | https://en.wikipedia.org/wiki?curid=22101239 |
GHS hazard statements Hazard statements form part of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). They are intended to form a set of standardized phrases about the hazards of chemical substances and mixtures that can be translated into different languages. As such, they serve the same purpose as the well-known R-phrases, which they are intended to replace. Hazard statements are one of the key elements for the labelling of containers under the GHS, along with: Each hazard statement is designated a code, starting with the letter H and followed by three digits. Statements which correspond to related hazards are grouped together by code number, so the numbering is not consecutive. The code is used for reference purposes, for example to help with translations, but it is the "actual phrase" which should appear on labels and safety data sheets. The European Union has implemented the GHS through the CLP Regulation. Nevertheless, the older system based on the Dangerous Substances Directive was used in parallel until June 2015. Some R-phrases which do not have simple equivalents under the GHS have been retained under the CLP Regulation: the numbering mirrors the number of the previous R-phrase. Some other hazard statements intended for use in very specific circumstances have also been retained under the CLP Regulation. Note that, in this case, the numbering of the EU specific hazard statements can coincide with if the "EU" prefix is not included | https://en.wikipedia.org/wiki?curid=22103184 |
GHS hazard statements The GHS was adopted in Australia from 1 January 2012 and becomes mandatory in States and Territories that have adopted the harmonised Work Health and Safety laws (other than Victoria and Western Australia) as of 1 January 2017. The National Code of Practice for the Preparation of Safety Data Sheets for Hazardous Chemicals includes 12 Australian-specific GHS Hazard Statements, as follows: As of March 2009, the relevant New Zealand regulations under the Hazardous Substances and New Organisms Act 1996 do not specify the exact wording required for hazard statements. However, the New Zealand classification system includes three categories of environmental hazard which are not included in the GHS Rev.2: These are classes 9.2–9.4 respectively of the New Zealand classification scheme, and are divided into subclasses according to the degree of hazard. Substances in subclass 9.2D ("Substances that are slightly harmful in the soil environment") do not require a hazard statement, while substances in the other subclasses require an indication of the general degree of hazard and general type of hazard. | https://en.wikipedia.org/wiki?curid=22103184 |
Hippo signaling pathway The Hippo signaling pathway, also known as the Salvador-Warts-Hippo (SWH) pathway, controls organ size in animals through the regulation of cell proliferation and apoptosis. The pathway takes its name from one of its key signaling components—the protein kinase Hippo (Hpo). Mutations in this gene lead to tissue overgrowth, or a "hippopotamus"-like phenotype. A fundamental question in developmental biology is how an organ knows to stop growing after reaching a particular size. Organ growth relies on several processes occurring at the cellular level, including cell division and programmed cell death (or apoptosis). The is involved in restraining cell proliferation and promoting apoptosis. As many cancers are marked by unchecked cell division, this signaling pathway has become increasingly significant in the study of human cancer. Hippo pathway also has critical role in stem cell and tissue specific progenitor cell self-renewal and expansion. The appears to be highly conserved. While most of the Hippo pathway components were identified in the fruit fly ("Drosophila melanogaster") using mosaic genetic screens, orthologs to these components (genes that function analogously in different species) have subsequently been found in mammals. Thus, the delineation of the pathway in "Drosophila" has helped to identify many genes that function as oncogenes or tumor suppressors in mammals. The Hippo pathway consists of a core kinase cascade in which Hpo phosphorylates the protein kinase Warts (Wts) | https://en.wikipedia.org/wiki?curid=22108748 |
Hippo signaling pathway Hpo (MST1/2 in mammals) is a member of the Ste-20 family of protein kinases. This highly conserved group of serine/threonine kinases regulates several cellular processes, including cell proliferation, apoptosis, and various stress responses. Once phosphorylated, Wts (LATS1/2 in mammals) becomes active. Misshapen (Msn, MAP4K4/6/7 in mammals) and Happyhour (Hppy, MAP4K1/2/3/5 in mammals) act in parallel to Hpo to activate Wts. Wts is a nuclear DBF-2-related kinase. These kinases are known regulators of cell cycle progression, growth, and development. Two proteins are known to facilitate the activation of Wts: Salvador (Sav) and Mob as tumor suppressor (Mats). Sav (WW45 in mammals) is a WW domain-containing protein, meaning that this protein contains a sequence of amino acids in which a tryptophan and an invariant proline are highly conserved. Hpo can bind to and phosphorylate Sav, which may function as a scaffold protein because this Hpo-Sav interaction promotes phosphorylation of Wts. Hpo can also phosphorylate and activate Mats (MOBKL1A/B in mammals), which allows Mats to associate with and strengthen the kinase activity of Wts. Activated Wts can then go on to phosphorylate and inactivate the transcriptional coactivator Yorkie (Yki). Yki is unable to bind DNA by itself. In its active state, Yki binds to the transcription factor Scalloped (Sd), and the Yki-Sd complex becomes localized to the nucleus | https://en.wikipedia.org/wiki?curid=22108748 |
Hippo signaling pathway This allows for the expression of several genes that promote organ growth, such as "cyclin E", which promotes cell cycle progression, and "diap1" ("Drosophila" inhibitor of apoptosis protein-1), which, as its name suggests, prevents apoptosis. Yki also activates expression of the "bantam" microRNA, a positive growth regulator that specifically affects cell number. Thus, the inactivation of Yki by Wts inhibits growth through the transcriptional repression of these pro-growth regulators. By phosphorylating Yki at serine 168, Wts promotes the association of Yki with 14-3-3 proteins, which help to anchor Yki in the cytoplasm and prevent its transport to the nucleus. In mammals, the two Yki orthologs are Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). When activated, YAP and TAZ can bind to several transcription factors including p73, Runx2 and several TEADs. YAP regulates the expression of Hoxa1 and Hoxc13 in mouse and human epithelial cells in vivo and in vitro. The upstream regulators of the core Hpo/Wts kinase cascade include the transmembrane protein Fat and several membrane-associated proteins. As an atypical cadherin, Fat (FAT1-4 in mammals) may function as a receptor, though an extracellular ligand has not been positively identified. While Fat is known to bind to another atypical cadherin, Dachsous (Ds), during tissue patterning, it is unclear what role Ds has in regulating tissue growth. Nevertheless, Fat is recognized as an upstream regulator of the Hpo pathway | https://en.wikipedia.org/wiki?curid=22108748 |
Hippo signaling pathway Fat activates Hpo through the apical protein Expanded (Ex; FRMD6/Willin in mammals). Ex interacts with two other apically-localized proteins, Kibra (KIBRA in mammals) and Merlin (Mer; NF2 in mammals), to form the Kibra-Ex-Mer (KEM) complex. Both Ex and Mer are FERM domain-containing proteins, while Kibra, like Sav, is a WW domain-containing protein. The KEM complex physically interacts with the Hpo kinase cascade, thereby localizing the core kinase cascade to the plasma membrane for activation. Fat may also regulate Wts independently of Ex/Hpo, through the inhibition of the unconventional myosin Dachs. Normally, Dachs can bind to and promote the degradation of Wts. In fruitfly, the involves a kinase cascade involving the Salvador (Sav), Warts (Wts) and Hippo (Hpo) protein kinases. Many of the genes involved in the are recognized as tumor suppressors, while Yki/YAP/TAZ is identified as an oncogene. YAP/TAZ can reprogram cancer cells into cancer stem cells. YAP has been found to be elevated in some human cancers, including breast cancer, colorectal cancer, and liver cancer. This may be explained by YAP’s recently defined role in overcoming contact inhibition, a fundamental growth control property of normal cells "in vitro" and "in vivo", in which proliferation stops after cells reach confluence (in culture) or occupy maximum available space inside the body and touch one another. This property is typically lost in cancerous cells, allowing them to proliferate in an uncontrolled manner | https://en.wikipedia.org/wiki?curid=22108748 |
Hippo signaling pathway In fact, YAP overexpression antagonizes contact inhibition. Many of the pathway components recognized as tumor suppressor genes are mutated in human cancers. For example, mutations in Fat4 have been found in breast cancer, while NF2 is mutated in familial and sporadic schwannomas. Additionally, several human cancer cell lines invoke mutations of the WW45 and MOBK1B proteins. However, recent research by Marc Kirschner and Taran Gujral has demonstrated that Hippo pathway components may play a more nuanced role in cancer than previously thought. Hippo pathway inactivation enhanced the effect of 15 FDA-approved oncology drugs by promoting chemo-retention. In another study, the Hippo pathway kinases LATS1/2 were found to suppress cancer immunity in mice. Two venture-backed oncology startups, Vivace Therapeutics and the General Biotechnologies subsidiary Nivien Therapeutics, are actively developing kinase inhibitors targeting the Hippo pathway. The heart is the first organ formed during mammalian development. A properly sized and functional heart is vital throughout the entire lifespan. Loss of cardiomyocytes because of injury or diseases leads to heart failure, which is a major cause of human morbidity and mortality. Unfortunately, regenerative potential of the adult heart is limited | https://en.wikipedia.org/wiki?curid=22108748 |
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