Classification Term: 4150
Homogeneous transition metal compounds (ontology term: CHEMONTID:0000426)
Inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom." []
found 29 associated metabolites at class metabolite taxonomy ontology rank level.
Ancestor: Homogeneous metal compounds
Child Taxonomies: There is no child term of current ontology term.
Copper
Copper is an essential nutrient to all higher plants and animals. Physiologically, it exists as an ion in the body. In animals, it is found primarily in the bloodstream, as a cofactor in various enzymes, and in copper-based pigments. In the body, copper shifts between the cuprous (Cu1+) and cupric (Cu2+) forms, though the majority of the bodys copper is in the Cu2+ form. The ability of copper to easily accept and donate electrons explains its important role in oxidation-reduction (redox) reactions and in scavenging free radicals. Copper is a critical functional component of a number of essential enzymes known as cuproenzymes. For instance, the copper-dependent enzyme, cytochrome c oxidase, plays a critical role in cellular energy production. By catalyzing the reduction of molecular oxygen (O2) to water (H2O), cytochrome c oxidase generates an electrical gradient used by the mitochondria to create the vital energy-storing molecule, ATP. Another cuproenzyme, lysyl oxidase, is required for the cross-linking of collagen and elastin, which are essential for the formation of strong and flexible connective tissue. Another cuproeznyme, Monoamine oxidase (MAO), plays a role in the metabolism of the neurotransmitters norepinephrine, epinephrine, and dopamine. MAO also functions in the degradation of the neurotransmitter serotonin, which is the basis for the use of MAO inhibitors as antidepressants. One of the most important cuproenzymes is Superoxide dismutase (SOD). SOD functions as an antioxidant by catalyzing the conversion of superoxide radicals (free radicals or ROS) to hydrogen peroxide, which can subsequently be reduced to water by other antioxidant enzymes. Two forms of SOD contain copper: 1) copper/zinc SOD is found within most cells of the body, including red blood cells, and 2) extracellular SOD is a copper-containing enzyme found at high levels in the lungs and low levels in blood plasma. In sufficient amounts, copper can be poisonous or even fatal to organisms. Copper is normally bound to cuproenzymes (such as SOD, MOA) and is thus only toxic when unsequestered and unmediated. It is believed that zinc and copper compete for absorption in the digestive tract so that a diet that is excessive in one of these minerals may result in a deficiency in the other. An imbalance of zinc and copper status might be involved in human hypertension. Furthermore, copper is found to be associated with hyperzincaemia and hypercalprotectinaemia and Wilsons disease, which are inborn errors of metabolism. Copper(2+), also known as copper, ion (cu2+) or copper (ii) ion, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Copper(2+) can be found in a number of food items such as common grape, black cabbage, loquat, and spelt, which makes copper(2+) a potential biomarker for the consumption of these food products. Copper(2+) can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine, as well as throughout most human tissues. Copper(2+) exists in all living species, ranging from bacteria to humans. In humans, copper(2+) is involved in several metabolic pathways, some of which include tyrosine metabolism, disulfiram action pathway, riboflavin metabolism, and histidine metabolism. Copper(2+) is also involved in several metabolic disorders, some of which include monoamine oxidase-a deficiency (MAO-A), hawkinsinuria, tyrosinemia type I, and alkaptonuria. Moreover, copper(2+) is found to be associated with alzheimers disease, wilsons disease, hyperzincaemia and hypercalprotectinaemia, and multiple sclerosis. Copper(2+) is a non-carcinogenic (not listed by IARC) potentially toxic compound. In cases of suspected copper poisoning, penicillamine is the drug of choice, and dimercaprol, a heavy metal chelating agent, is often administered. Vinegar is not recommended, as it assists in solubilizing insoluble copper salts (T3DB). G - Genito urinary system and sex hormones > G02 - Other gynecologicals > G02B - Contraceptives for topical use > G02BA - Intrauterine contraceptives D018977 - Micronutrients > D014131 - Trace Elements
Molybdenum
Molybdenum is a transition metal with the atomic symbol Mo, atomic number 42, and atomic weight 95.94. The pure metal is silvery white in color, fairly soft, and has one of the highest melting points of all pure elements. Physiologically, it exists as an ion in the body. It is an essential trace element, being a component of the enzymes xanthine oxidase, aldehyde oxidase, and nitrate reductase. There is a trace requirement for molybdenum in plants, and soils can be barren due to molybdenum deficiencies. Plants and animals generally have molybdenum present in amounts of a few parts per million. In animals molybdenum is a cofactor of the enzyme xanthine oxidase which is involved in the pathways of purine degradation and formation of uric acid. In some animals, adding a small amount of dietary molybdenum enhances growth. Francis Crick suggested that since molybdenum is an essential trace element that plays an important role in many enzymatic reactions, despite being less abundant than the more common elements, such as chromium and nickel, that perhaps this fact is indicative of "Panspermia." Crick theorized that if it could be shown that the elements represented in terrestrial living organisms correlate closely with those that are abundant in some class of star - molybdenum stars, for example, that this would provide evidence of such Directed Panspermia. In small quantities, molybdenum is effective at hardening steel. Molybdenum is important in plant nutrition, and is found in certain enzymes, including xanthine oxidase. Molybdenum is used to this day in high-strength alloys and in high-temperature steels. Special molybdenum-containing alloys, such as the Hastelloys, are notably heat-resistant and corrosion-resistant. Molybdenum is used in oil pipelines, aircraft and missile parts, and in filaments. Molybdenum finds use as a catalyst in the petroleum industry, especially in catalysts for removing organic sulfurs from petroleum products. It is used to form the anode in some x-ray tubes, particularly in mammography applications. And is found in some electronic applications as the conductive metal layers in thin-film transistors (TFTs). Molybdenum disulfide is a good lubricant, especially at high temperatures. And Mo-99 is used in the nuclear isotope industry. Molybdenum pigments range from red-yellow to a bright red orange and are used in paints, inks, plastics, and rubber compounds. Molybdenum is a Group 6 chemical element with the symbol Mo and atomic number 42. The free element, which is a silvery metal, has the sixth-highest melting point of any element. It readily forms hard, stable carbides, and for this reason it is often used in high-strength steel alloys. Molybdenum does not occur as a free metal on Earth, but rather in various oxidation states in minerals. Industrially, molybdenum compounds are used in high-pressure and high-temperature applications, as pigments and catalysts. Molybdenum-containing enzymes are used as catalysts by some bacteria to break the chemical bond in atmospheric molecular nitrogen, allowing biological nitrogen fixation. At least 50 molybdenum-containing enzymes are now known in bacteria and animals, though only the bacterial and cyanobacterial enzymes are involved in nitrogen fixation. Owing to the diverse functions of the remainder of the enzymes, molybdenum is a required element for life in higher organisms (eukaryotes), though not in all bacteria. [Wikipedia]. Molybdenum is found in many foods, some of which are cabbage, gooseberry, french plantain, and turnip. D018977 - Micronutrients > D014131 - Trace Elements
Tungsten
W (183.950953)
Tungsten is a transition metal found, along with chromium, molybdenum and seaborgium, in Group VI of the Periodic Table of elements. Since its discovery in the last quarter of 18th century, tungsten-based products have been in use in a wide range of applications stretching from daily household necessities to highly specialized components of modern science and technology. As new applications and uses are discovered continuously, interest on and demand for tungsten, already an essential commodity, are projected to increase steadily in the years to come. Unavoidably, as is the case with other natural materials and/or non-renewable resources, increased demand and use of tungsten will spawn (a) increased interactions with other materials and/or non-sustainable practices, (b) a greater number of possible entry points into the natural and human environment and (c) a higher probability of deliberate or accidental releases. Currently, the existing knowledge base does not provide clear information about the behavior of tungsten-based products in the environment. The toxicological profile of tungsten, including possible effects on living organisms and exposure pathways, remains rather sketchy, narrow and fragmentary. Regulation of tungsten, both in terms of environmental and occupational safety and health, is at present limited in comparison with other metals. This pattern of environmental obscurity has been unequivocally disrupted by the events of Fallon, Nevada and the possible implication of tungsten to an acute lymphocytic leukemia (ALL) cluster. Tungsten is now the focus of scrutiny as it currently occupies the top of to do lists of various regulatory, health and environmental agencies. The occurrence of a childhood leukemia cluster in Fallon, Nevada prompted a wide investigation that involved several local, state and federal agencies led by the Centers of Disease Control (CDC). In essence, the objective of this investigation was to assess whether environmental causes were responsible for the cluster. The 16 reported leukemia cases within the time frame of 1997-2001, were well above the average for Nevada (3.0 cases/100,000 children/5 years). Several possible causes were proposed, such as jet fuel (JP-8) from a nearby military base or from a JP-8 pipeline running through the city, high levels of arsenic and other metals in the drinking water supplies, industrial pollution from a local tungsten smelting facility, and agrochemical contamination resulting from agricultural pesticide/fungicide use. Although the exact causes of leukemia are not well known, genetic and/or environmental factors may trigger the disease including ionizing and electromagnetic radiation, infectious and chemical agents. Physiologically, it exists as an ion in the body.(PMID: 16343746). Tungsten is a chemical element with the chemical symbol W and atomic number 74. Tungsten is the only metal from the third transition series that is known to occur in biomolecules, where it is used in a few species of bacteria. It is the heaviest element known to be used by any living organism. Tungsten interferes with molybdenum and copper metabolism, and is somewhat toxic to animal life. [Wikipedia]. Tungsten is found in many foods, some of which are orange bell pepper, black walnut, parsnip, and eggplant.
Pentanoyl-CoA
Pentanoyl CoA is an acyl-CoA with the C-5 Acyl chain. Acyl-CoA (or formyl-CoA) is a coenzyme involved in the metabolism of fatty acids. It is a temporary compound formed when coenzyme A (CoA) attaches to the end of a long-chain fatty acid, inside living cells. The CoA is then removed from the chain, carrying two carbons from the chain with it, forming acetyl-CoA. This is then used in the citric acid cycle to start a chain of reactions, eventually forming many adenosine triphosphates. To be oxidatively degraded, a fatty acid must first be activated in a two-step reaction catalyzed by acyl-CoA synthetase. First, the fatty acid displaces the diphosphate group of ATP, then coenzyme A (HSCoA) displaces the AMP group to form an Acyl-CoA. The acyladenylate product of the first step has a large free energy of hydrolysis and conserves the free energy of the cleaved phosphoanhydride bond in ATP. The second step, transfer of the acyl group to CoA (the same molecule that carries acetyl groups as acetyl-CoA), conserves free energy in the formation of a thioester bond. Consequently, the overall reaction Fatty acid + CoA + ATP <=> Acyl-CoA + AMP + PPi has a free energy change near zero. Subsequent hydrolysis of the product PPi (by the enzyme inorganic pyrophosphatase) is highly exergonic, and this reaction makes the formation of acyl-CoA spontaneous and irreversible. Fatty acids are activated in the cytosol, but oxidation occurs in the mitochondria. Because there is no transport protein for CoA adducts, acyl groups must enter the mitochondria via a shuttle system involving the small molecule carnitine. Pentanoyl coA is a acyl-CoA with the C-5 Acyl chain.
Cadmium
Cd (113.903361)
Cadmium (group IIB of the periodic table of elements) is a heavy metal. It is not a naturally occurring metal in biological systems. Cadmium poses severe risks to human health. Physiologically, it exists as an ion in the body. Up to this day, it has not been shown that cadmium has any physiological function within the human body. Interest has therefore risen in its biohazardous potential. As first described by Friedrich Stromeyer (Gottingen, Germany) in 1817, cadmium intoxication can lead to kidney, bone, and pulmonary damage. Cadmium is widely used in industrial processes, e.g as an anticorrosive agent, as a stabilizer in PVC products, as a colour pigment, a neutron absorber in nuclear power plants, and in the fabrication of nickel cadmium batteries. Phosphate fertilizers also show a big cadmium load. Although some cadmium containing products can be recycled, a large share of the general cadmium pollution is caused by dumping and incinerating cadmium polluted waste. In Scandinavia for example, cadmium concentration in agricultural soil increases by 0.2 percent per year. Total global emission of cadmium amounts to 7000 t/year. The maximum permissible value for workers according to German law is 15 ug/l. For comparison: Non-smokers show an average cadmium blood concentration of 0.5 ug/l. Basically there are three possible ways of cadmium resorption: Gastrointestinal, pulmonary and dermal. The uptake through the human gastrointestinal is approximately 5 percent of an ingested amount of cadmium, depending on the exact dose and nutritional composition. The major source of inhalative cadmium intoxication is cigarette smoke. The human lung resorbes 40 to 60 percent of the cadmium in tobacco smoke. Little research has been done on dermal absorption of cadmium. Two mechanisms facilitate cadmium absorption by the skin: binding of a free cadmium ion to sulfhydryl radicals of cysteine in epidermal keratins, or an induction and complexing with metallothionein. Once taken up by the blood, the majority of cadmium is transported bound to proteins, such as Albumin and Metallothionein. The first organ reached after cadmium uptake into the GI-blood is the liver. Here cadmium induces the production of Metallothionein. After consecutive hepatocyte necrosis and apoptosis, Cd-Metallothionein complexes are washed into sinusoidal blood. From here, parts of the absorbed cadmium enter the entero-hepatical cycle via secretion into the biliary tract in form of Cadmium-glutathione conjugates. Enzymatically degraded to cadmium-cysteine complexes in the biliary tree, cadmium reenters the small intestines. The main organ for long-term cadmium accumulation is the kidney. Here the half life period for cadmium is approximately 10 years. A life long intake can therefore lead to a cadmium accumulation in the kidney, consequently resulting in tubulus cell necrosis. The blood concentration of cadmium serves as a reliable indicator for a recent exposition, while the urinary concentration reflects past exposure, body burden and renal accumulation. Excretion of Cadmium takes place via faeces and urine. (PMID: 16961932). Cadmium, also known as cadmium, ion (cd2+) or cadmium ion, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Cadmium can be found in a number of food items such as capers, horseradish, malabar spinach, and wax apple, which makes cadmium a potential biomarker for the consumption of these food products. Cadmium can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine. Moreover, cadmium is found to be associated with alzheimers disease, macular degeneration, multiple sclerosis, and parkinsons disease. Cadmium is formally rated as a carcinogenic (IARC 1) potentially toxic compound. Cadmium is a chemical element with symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11. Cadmium and its congeners in group 12 are often not considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earths crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate . Acute inhalation of cadmium fumes results in metal fume fever, which is characterized by chills, fever, headache, weakness, dryness of the nose and throat, chest pain, and coughing. Ingestion of cadmium causes vomiting and diarrhea (L6) (T3DB).
Silver
Ag (106.905095)
Among metals, pure silver has the highest thermal conductivity (the non-metal diamond and superfluid helium II are higher) and one of the highest optical reflectivity. (Aluminium slightly outdoes silver in parts of the visible spectrum, and silver is a poor reflector of ultraviolet light). Silver also has the lowest contact resistance of any metal. Silver halides are photosensitive and are remarkable for their ability to record a latent image that can later be developed chemically. Silver is stable in pure air and water, but tarnishes when it is exposed to air or water containing ozone or hydrogen sulfide to form a black layer of silver sulfide which can be cleaned off with dilute hydrochloric acid. The most common oxidation state of silver is +1 (for example, silver nitrate: AgNO3); in addition, +2 compounds (for example, silver(II) fluoride: AgF2) and +3 compounds (for example, potassium tetrafluoroargentate: K[AgF4]) are known.; Hippocrates, the "father of medicine", wrote that silver had beneficial healing and anti-disease properties, and the Phoenicians used to store water, wine, and vinegar in silver bottles to prevent spoiling. In the early 1900s people would put silver dollars in milk bottles to prolong the milks freshness. Its germicidal effects increased its value in utensils and as jewellery. The exact process of silvers germicidal effect is still not well understood, although theories exist. One of these is the oligodynamic effect, which explains the effect on microorganisms but would not explain antiviral effects.; Jewellery and silverware are traditionally made from sterling silver (standard silver), an alloy of 92.5\\% silver with 7.5\\% copper. In the United States, only an alloy consisting of at least 92.5\\% fine silver can be marketed as "silver". Sterling silver is harder than pure silver, and has a lower melting point (893 °C) than either pure silver or pure copper. Britannia silver is an alternative hallmark-quality standard containing 95.8\\% silver, often used to make silver tableware and wrought plate. With the addition of germanium, the patented modified alloy Argentium Sterling Silver is formed, with improved properties including resistance to firescale.; Silver bromide is a yellow, low hardness salt.; Silver is a chemical element with the chemical symbol Ag (Latin: argentum) and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold (electrum) and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a by-product of copper, gold, lead, and zinc refining.; Silver is a constituent of almost all colored carat gold alloys and carat gold solders, giving the alloys paler colour and greater hardness. White 9 carat gold contains 62.5\\% silver and 37.5\\% gold, while 22 carat gold contains up to 8.4\\% silver or 8.4\\% copper.; Silver is a very ductile and malleable (slightly harder than gold) monovalent coinage metal with a brilliant white metallic luster that can take a high degree of polish. It has the highest electrical conductivity of all metals, even higher than copper, but its greater cost and tarnishability have prevented it from being widely used in place of copper for electrical purposes, though 13,540 tons were used in the electromagnets used for enriching uranium during World War II (mainly because of the wartime shortage of copper). Another notable exception is in high-end audio cables.; Silver is commonly used in catheters. Silver alloy catheters are more effective than standard catheters for reducing bacteriuria in adults in hospital having short term catheterisation.This meta-analysis clarifies discrepant results among trials of silver-coated urinary catheters by revealing that silver alloy catheters are significantly more effective in preventing urinary tract infectio... Silver is widely distributed in the earths crust and is found in soil, fresh and sea water, and the air. It is readily absorbed into the human body with food and drink and through inhalation, but the low levels of silver commonly present in the bloodstream (< 2.3 b.mu g/L) and in key tissues like liver and kidney have not been associated with any disease or disability. Silver is not an acknowledged trace element in the human body and fulfills no physiological or biochemical role in any tissue even though it interacts with several essential elements including zinc and calcium. Physiologically, it exists as an ion in the body. Silver has a long history in the treatment of human diseases, including epilepsy, neonatal eye disease, venereal diseases, and wound infections. It has been employed in water purification and is currently used to safeguard hospital hot water systems against Legionella infections. Principle routes of human exposure to silver nowadays are through its widespread use as an antimicrobial agent in wound care products and medical devices, including in-dwelling catheters, bone cements, cardiac valves and prostheses, orthopedic pins, and dental devices. In each case, the antimicrobial properties of silver are dependent upon release of biologically active silver ion (Ag*) from metallic silver (including nanocrystalline forms), silver nitrate, silver sulfadiazine, and other silver compounds incorporated in the various devices, and its lethal effect on pathogenic organisms. Experience has shown that a large proportion of the silver ion released from medical devices not required for antimicrobial action is disseminated into tissue fluids and exudates, where it combines with albumins and macroglobulins. These silver-protein complexes are absorbed into the systemic circulation to be deposited in key soft tissues, including the skin, liver, kidney, spleen, lungs, and brain. As a xenobiotic material, silver must be presumed to present a health risk to exposed persons under some circumstances. Unlike the well-documented neurotoxic metals including lead and mercury, silver does not appear to be a cumulative poison and is eliminated from the body through the urine and feces. Excretion of silver by these routes may be a measure of mean daily intake, but since this view is based largely on the clinical use of silver nitrate and silver sulfadiazine used in burn wound therapy, its true relevance in the metabolism of silver used in the wider context of medical devices is questionable. Argyria is the most widely publicized clinical condition associated with silver accumulation in blood and soft tissues. It commonly occurs in individuals exposed to high levels of silver occupationally (metallurgy, photography, and mining industries), or consuming or inhaling silver hygiene products (including colloidal silver products) for long periods. Silver is absorbed into the body and deposited in the perivascular regions of the skin and other soft tissues as black granules of silver sulfide or silver selenide. The resulting slate grey discoloration of the skin occasionally associated with melanogenic changes, is semipermanent and cosmetically undesirable but is not known to be life-threatening. (PMID: 17453933). D - Dermatologicals > D08 - Antiseptics and disinfectants > D08A - Antiseptics and disinfectants > D08AL - Silver compounds COVID info from clinicaltrial, clinicaltrials, clinical trial, clinical trials Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS
Fe2+
Iron is a chemical element with the symbol Fe and atomic number 26. Iron makes up 5\\% of the Earths crust and is second in abundance to aluminium among the metals and fourth in abundance among the elements. Physiologically, it. exists as an ion in the body. Iron (as Fe2+, ferrous ion) is a necessary trace element used by all known living organisms. Iron-containing enzymes, usually containing heme prosthetic groups, participate in catalysis of oxidation reactions in biology, and in transport of a number of soluble gases. Iron is an essential constituent of hemoglobin, cytochrome, and other components of respiratory enzyme systems. Its chief functions are in the transport of oxygen to tissue (hemoglobin) and in cellular oxidation mechanisms. Inorganic iron involved in redox reactions is also found in the iron-sulfur clusters of many enzymes, such as nitrogenase (involved in the synthesis of ammonia from nitrogen and hydrogen) and hydrogenase. A class of non-heme iron proteins is responsible for a wide range of functions such as ribonucleotide reductase (reduces ribose to deoxyribose; DNA biosynthesis) and purple acid phosphatase (hydrolysis of phosphate esters). When the body is fighting a bacterial infection, the body sequesters iron inside of cells (mostly stored in the storage molecule ferritin) so that it cannot be used by bacteria. Depletion of iron stores may result in iron-deficiency anemia. Iron is used to build up the blood in anemia. Humans experience iron toxicity above 20 milligrams of iron for every kilogram of weight, and 60 milligrams per kilogram is a lethal dose. Over-consumption of iron, often the result of children eating large quantities of ferrous sulfate tablets intended for adult consumption, is the most common toxicological cause of death in children under six. The DRI lists the Tolerable Upper Intake Level (UL) for adults as 45 mg/day. For children under fourteen years old the UL is 40 mg/day. Iron is a metal extracted from iron ore, and is almost never found in the free elemental state. Fe2+, also known as fe (ii) ion or fe(ii), is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Fe2+ can be found in a number of food items such as soft-necked garlic, yardlong bean, common verbena, and purslane, which makes fe2+ a potential biomarker for the consumption of these food products. Fe2+ can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine, as well as in human brain and liver tissues. Fe2+ exists in all living species, ranging from bacteria to humans. In humans, fe2+ is involved in several metabolic pathways, some of which include carnitine synthesis, cystinosis, ocular nonnephropathic, porphyrin metabolism, and catecholamine biosynthesis. Fe2+ is also involved in several metabolic disorders, some of which include tyrosinemia type 2 (or richner-hanhart syndrome), tyrosinemia type 3 (TYRO3), dihydropyrimidinase deficiency, and tyrosine hydroxylase deficiency. Moreover, fe2+ is found to be associated with alzheimers disease, multiple sclerosis, and parkinsons disease.
Iron
Iron is a metallic element found in certain minerals, in nearly all soils, and in mineral waters. Iron is required for life. It exists in all living species, ranging from bacteria to humans. It can be found primarily in blood and it is an essential constituent of hemoglobin, cytochrome, and other components of respiratory enzyme systems. Its chief functions are in the transport of oxygen to tissue (hemoglobin) and in cellular oxidation mechanisms. Depletion of iron stores may result in iron-deficiency anemia. Iron is used to build up the blood in anemia. In humans, iron is involved in several metabolic pathways, some of which include the rofecoxib pathway, magnesium salicylate action pathway, etodolac pathway, and diclofenac pathway. Iron is also involved in several metabolic disorders, some of which include adenine phosphoribosyltransferase deficiency (APRT), porphyria variegata (PV), adenylosuccinate lyase deficiency, and AICA-ribosiduria. The major activity of supplemental iron is in the prevention and treatment of iron-deficiency anemia. Iron has putative immune-enhancing, anticarcinogenic, and cognition-enhancing activities. Iron can be found in a number of food items such as chinese water chestnut, hyssop, daikon radish, and peppermint, which makes it a potential biomarker for the consumption of these food products. The major activity of supplemental iron is in the prevention and treatment of iron deficiency anemia. Iron has putative immune-enhancing, anticarcinogenic and cognition-enhancing activities. [HMDB]. Fe3+ is found in many foods, some of which are epazote, common chokecherry, elderberry, and persimmon.
Vanadium
Vanadium is a steel-grey, corrosion-resistant metal, which exists in oxidation states ranging from -1 to +5. Metallic vanadium does not occur in nature, and the most common valence states are +3, +4, and +5. The pentavalent form (VO3-) predominates in extracellular body fluids whereas the quadrivalent form (VO+2) is the most common intracellular form. Because of its hardness and its ability to form alloys, vanadium (i.e., ferrovanadium) is a common component of hard steel alloys used in machines and tools. Although most foods contain low concentrations of vanadium (< 1 ng/g), food is the major source of exposure to vanadium for the general population. High air concentrations of vanadium occur in the occupation setting during boiler-cleaning operations as a result of the presence of vanadium oxides in the dust. The lungs absorb soluble vanadium compounds (V2O5) well, but the absorption of vanadium salts from the gastrointestinal tract is poor. The excretion of vanadium by the kidneys is rapid with a biological half-life of 20-40 hours in the urine. Physiologically, it exists as an ion in the body. Vanadium is probably an essential trace element, but a vanadium-deficiency disease has not been identified in humans. The estimated daily intake of the US population ranges from 10-60 micrograms V. Vanadyl sulfate is a common supplement used to enhance weight training in athletes at doses up to 60 mg/d. In vitro and animal studies indicate that vanadate and other vanadium compounds increase glucose transport activity and improve glucose metabolism. In general, the toxicity of vanadium compounds is low. Pentavalent compounds are the most toxic and the toxicity of vanadium compounds usually increases as the valence increases. Most of the toxic effects of vanadium compounds result from local irritation of the eyes and upper respiratory tract rather than systemic toxicity. The only clearly documented effect of exposure to vanadium dust is upper respiratory tract irritation characterized by rhinitis, wheezing, nasal hemorrhage, conjunctivitis, cough, sore throat, and chest pain. Case studies have described the onset of asthma after heavy exposure to vanadium compounds, but clinical studies to date have not detected an increased prevalence of asthma in workers exposed to vanadium. Vanadium is a trace element present in practically all cells in plants and animals. It exerts interesting actions in living systems. At pharmacological doses, vanadium compounds display relevant biological actions such as mimicking insulin and growth factors as well as having osteogenic activity. Some vanadium compounds also show antitumoral properties. The importance of vanadium in bone arises from the studies developed to establish the essentiality of this element in animals and humans. Bone tissue, where the element seems to play an important role, accumulates great amounts of vanadium. Among several metals, vanadium has emerged as an extremely potent agent with insulin-like properties. These insulin-like properties have been demonstrated in isolated cells, tissues, different animal models of type I and type II diabetes as well as a limited number of human subjects. Vanadium treatment has been found to improve abnormalities of carbohydrate and lipid metabolism and of gene expression in rodent models of diabetes. In isolated cells, it enhances glucose transport, glycogen and lipid synthesis, and inhibits gluconeogenesis and lipolysis. The molecular mechanism responsible for the insulin-like effects of vanadium compounds have been shown to involve the activation of several key components of insulin-signaling pathways that include the mitogen-activated-protein kinases (MAPKs) extracellular signal-regulated kinase 1/2 (ERK1/2) and p38MAPK, and phosphatidylinositol 3-kinase (PI3-K)/protein kinase B (PKB). (PMID: 16998531, 16456236, 10382561)
Zinc
Zinc, also known as zinc ion or zn2+, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Zinc can be found in a number of food items such as sunburst squash (pattypan squash), star fruit, kelp, and common salsify, which makes zinc a potential biomarker for the consumption of these food products. Zinc can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine, as well as in human brain, erythrocyte and liver tissues. Zinc exists in all living species, ranging from bacteria to humans. In humans, zinc is involved in several metabolic pathways, some of which include pantoprazole action pathway, pyruvate metabolism, cimetidine action pathway, and phenylbutazone action pathway. Zinc is also involved in several metabolic disorders, some of which include gamma-glutamyltransferase deficiency, 3-phosphoglycerate dehydrogenase deficiency, MNGIE (mitochondrial neurogastrointestinal encephalopathy), and cystathionine beta-synthase deficiency. Moreover, zinc is found to be associated with continuous ambulatory peritoneal dialysis, kidney disease, chronic renal failure, and hemodialysis. Zinc is a non-carcinogenic (not listed by IARC) potentially toxic compound. The element was probably named by the alchemist Paracelsus after the German word Zinke (prong, tooth). German chemist Andreas Sigismund Marggraf is credited with discovering pure metallic zinc in 1746. Work by Luigi Galvani and Alessandro Volta uncovered the electrochemical properties of zinc by 1800. Corrosion-resistant zinc plating of iron (hot-dip galvanizing) is the major application for zinc. Other applications are in electrical batteries, small non-structural castings, and alloys such as brass. A variety of zinc compounds are commonly used, such as zinc carbonate and zinc gluconate (as dietary supplements), zinc chloride (in deodorants), zinc pyrithione (anti-dandruff shampoos), zinc sulfide (in luminescent paints), and zinc methyl or zinc diethyl in the organic laboratory . Ingestion of large doses of zinc causes stomach cramps, nausea, and vomiting. Acute inhalation of large amounts of zinc causes metal fume fever, which is characterized by chills, fever, headache, weakness, dryness of the nose and throat, chest pain, and coughing. Dermal contact with zinc results in skin irritation (L49) (T3DB). Zinc is an essential element, necessary for sustaining all life. It is a trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Physiologically, it exists as an ion in the body. It is estimated that 3000 of the hundreds of thousands of proteins in the human body contain zinc prosthetic groups. In addition, there are over a dozen cell types in the human body that secrete zinc ions, and the roles of these secreted zinc signals in medicine and health are now being actively studied. Intriguingly, brain cells in the mammalian forebrain are one type of cell that secretes zinc, along with its other neuronal messenger substances. Cells in the salivary gland, prostate, immune system, and intestine are other types that secrete zinc. Obtaining a sufficient zinc intake during pregnancy and in young children is a problem, especially among those who cannot afford a good and varied diet. Zinc deficiency is associated with anemia, short stature, hypogonadism, impaired wound healing, and geophagia. Brain development is stunted by zinc deficiency in utero and in youth. Zinc is an activator of certain enzymes, such as carbonic anhydrase. Carbonic anhydrase is important in the transport of carbon dioxide in vertebrate blood. Even though zinc is an essential requirement for a healthy body, too much zinc can be harmful. Excessive absorption of zinc can also suppress copper and iron absorption. The free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate fish. The Free Ion Activity Model (FIAM) is well-established in the literature and shows that just micromolar amounts of the free ion kill some organisms.
Cobalt
Cobalt has a molecular weight of 58.9 and an atomic number of 27. In the Periodic Table, close to other transition metals, it is situated in group 8, together with rhodium and iridium and it can occur in four oxidation states (0, +2, +3 and +4). The +2 and the ground state are the most common. Cobalt occurs in the minerals cobaltite (Co, Fe) AsS, smaltite (CoAs2), and erythrite Co3(AsO4)2.8H2O, and is often associated with nickel, silver, lead, copper, and iron ores, from which it is most frequently obtained as a by-product. Depending on the considered species, cobalt has multiple industrial applications including the production of alloys and hard metal, diamond polishing, drying agents, pigments and catalysts. Hard metal or cemented carbide is a powder metallurgical product consisting of hard, wear-resistant carbide particles bound together (cemented) with a ductile metal binder (i.e. metallic Co) by liquid phase sintering. Tungsten carbide (WC) is produced by mixing tungsten powder with pure carbon powder at high temperature; hereafter WC is mixed with Co powder to which paraffin is added as a binder. Depending on specific requirements related to their use, hard metals might additionally contain small quantities of chromium, niobium, molybdenum, titanium, tantalum or vanadium carbides. Inhalation and skin contact are the main occupational exposure routes. Occupational exposure to cobalt may result in adverse health effects in different organs or tissues, including the respiratory tract, the skin, the hemapoietic tissues, the myocardium or the thyroid gland. In addition, teratogenic and carcinogenic effects have been observed in experimental systems and/or in humans. For the general population, the diet constitutes the main route of exposure to cobalt, since it is an essential component of Vitamin B12 (hydroxycolalamin). Cobalt functions as a co-factor in enzyme catalysed reactions and is involved in the production of erythropoietin, a hormone that stimulates the formation of erythrocytes. This last property of cobalt was applied in the past as a therapy for anaemia. The carcinogenic potential of cobalt and its compounds was evaluated in 1991 by the International Agency for Research on Cancer (IARC), which concluded that there was inadequate evidence for carcinogenicity in humans (lung cancer) but sufficient evidence in experimental animal studies. In most experimental studies considered, the routes of exposure were, however, of questionable relevance for cancer risk assessment in humans for example, local sarcomas after intra-muscular injection. The general conclusion was that cobalt and its compounds are possibly carcinogenic to humans (group 2B). Since this evaluation, additional data have been accumulated which generally indicate that, depending on the considered cobalt species, different outcomes regarding toxicity, mutagenicity and carcinogenicity can be observed. Physiologically, it exists as an ion in the body. Co(II) ions are genotoxic in vitro and in vivo, and carcinogenic in rodents. Co metal is genotoxic in vitro. Hard metal dust, of which occupational exposure is linked to an increased lung cancer risk, is proven to be genotoxic in vitro and in vivo. Possibly, production of active oxygen species and/or DNA repair inhibition are mechanisms involved. Given the recently provided proof for in vitro and in vivo genotoxic potential of hard metal dust, the mechanistic evidence of elevated production of active oxygen species and the epidemiological data on increased cancer risk, it may be advisable to consider the possibility of a new evaluation by IARC.(PMID: 14643417). Cobalt has a molecular weight of 58.9 and an atomic number of 27. In the Periodic Table, close to other transition metals, it is situated in group 8, together with rhodium and iridium and it can occur in four oxidation states (0, +2, +3 and +4). The +2 and the ground state are the most common. Cobalt occurs in the minerals cobaltite (Co, Fe) AsS, smaltite (CoAs2), and erythrite Co3(AsO4)2.8H2O, and is often associated with nickel, silver, lead, copper, and iron ores, from which it is most frequently obtained as a by-product.
Mercury
Hg (201.970632)
Mercury is a metal that is a liquid at room temperature. Mercury has a long and interesting history deriving from its use in medicine and industry, with the resultant toxicity produced. In high enough doses, all forms of mercury can produce toxicity. The most devastating tragedies related to mercury toxicity in recent history include Minamata Bay and Niagata, Japan in the 1950s, and Iraq in the 1970s. More recent mercury toxicity issues include the extreme toxicity of the dimethylmercury compound noted in 1998, the possible toxicity related to dental amalgams, and the disproved relationship between vaccines and autism related to the presence of the mercury-containing preservative, thimerosal. Hair has been used in many studies as a bioindicator of mercury exposure for human populations. At the time of hair formation, mercury from the blood capillaries penetrates into the hair follicles. As hair grows approximately 1 cm each month, mercury exposure over time is recapitulated in hair strands. Mercury levels in hair closest to the scalp reflect the most recent exposure, while those farthest from the scalp are representative of previous blood concentrations. Sequential analyses of hair mercury have been useful for identifying seasonal variations over time in hair mercury content, which may be the result of seasonal differences in bioavailability of fish and differential consumption of piscivorous and herbivorous fish species. Knowledge of the relation between fish-eating practices and hair mercury levels is particularly important for adequate mitigation strategies. Physiologically, it exists as an ion in the body. Methyl mercury is well absorbed, and because the biological half-life is long, the body burden in humans may reach high levels. People who frequently eat contaminated seafood can acquire mercury concentrations that are potentially dangerous to the fetus in pregnant women. The dose-response relationships have been extensively studied, and the safe levels of exposure have tended to decline. Individual methyl mercury exposure is usually determined by analysis of mercury in blood and hair. Whilst the clinical features of acute mercury poisoning have been well described, chronic low dose exposure to mercury remains poorly characterised and its potential role in various chronic disease states remains controversial. Low molecular weight thiols, i.e. sulfhydryl containing molecules such as cysteine, are emerging as important factors in the transport and distribution of mercury throughout the body due to the phenomenon of "Molecular Mimicry" and its role in the molecular transport of mercury. Chelation agents such as the dithiols sodium 2,3-dimercaptopropanesulfate (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) are the treatments of choice for mercury toxicity. Alpha-lipoic acid (ALA), a disulfide, and its metabolite dihydrolipoic acid (DHLA), a dithiol, have also been shown to have chelation properties when used in an appropriate manner. Whilst N-acetyl-cysteine (NAC) and glutathione (GSH) have been recommended in the treatment of mercury toxicity in the past, an examination of available evidence suggests these agents may in fact be counterproductive. Zinc and selenium have also been shown to exert protective effects against mercury toxicity, most likely mediated by induction of the metal binding proteins metallothionein and selenoprotein-P. Evidence suggests however that the co-administration of selenium and dithiol chelation agents during treatment may also be counter-productive. Finally, the issue of diagnostic testing for chronic, historical or low dose mercury poisoning is considered including an analysis of the influence of ligand interactions and nutritional factors upon the accuracy of "chelation challenge" tests. (PMID: 17448359, 17408840, 17193738). Hg2+, also known as hg(2+) or mercuric ion, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Hg2+ can be found in a number of food items such as winter squash, thistle, greenthread tea, and japanese pumpkin, which makes hg2+ a potential biomarker for the consumption of these food products. Hg2+ can be found primarily in blood, cerebrospinal fluid (CSF), and urine. Moreover, hg2+ is found to be associated with alzheimers disease, multiple sclerosis, and parkinsons disease. Hg2+ is formally rated as an unfounded non-carcinogenic (IARC 3) potentially toxic compound. Mercury poisoning is treated by immediate decontamination and chelation therapy using DMSA, DMPS, DPCN, or dimercaprol (A7) Identifying and removing the source of the mercury is crucial. Decontamination requires removal of clothes, washing skin with soap and water, and flushing the eyes with saline solution as needed. Inorganic ingestion such as mercuric chloride should be approached as the ingestion of any other serious caustic. Immediate chelation therapy is the standard of care for a patient showing symptoms of severe mercury poisoning or the laboratory evidence of a large total mercury load. Chelation therapy for acute inorganic mercury poisoning can be done with DMSA (dimercaptosuccinic acid), 2,3-dimercapto-1-propanesulfonic acid (DMPS), D-penicillamine (DPCN), or dimercaprol (BAL). Only DMSA is FDA-approved for use in children for treating mercury poisoning (T3DB).
Chromium
Chromium is a naturally occurring heavy metal found in the environment commonly in trivalent, Cr(III), and hexavalent, Cr(VI), forms. The reduction of Cr(VI) to Cr(III) results in the formation of reactive intermediates that contribute to the cytotoxicity, genotoxicity and carcinogenicity of Cr(VI)-containing compounds. The major non-occupational source of chromium for humans is food such as vegetables, meat, urban air, hip or knee prostheses and cigarettes. Cr(VI) is a widely used in industrial chemicals, extensively used in paints, metal finishes, steel including stainless steel manufacturing, alloy cast irons, chrome and wood treatment. On the contrary, Cr(III) salts such as chromium polynicotinate, chromium chloride and chromium picolinate (CrP) are used as micronutrients and nutritional supplements and have been demonstrated to exhibit a significant number of health benefits in animals and humans. Physiologically, it exists as an ion in the body. Chromium enters the body through the lungs, gastro-intestinal tract and to a lesser extent through skin. Inhalation is the most important route for occupational exposure, whereas non-occupational exposure occurs via ingestion of chromium-containing food and water. Regardless of route of exposure Cr(III) is poorly absorbed whereas Cr(VI) is more readily absorbed. Further, absorption of Cr(VI) is poorer by oral route, it is thus not very toxic when introduced by the oral route. But chromium is very toxic by dermal and inhalation routes and causes lung cancer, nasal irritation, nasal ulcer, hypersensitivity reactions and contact dermatitis. All the ingested Cr(VI) is reduced to Cr(III) before entering in the blood stream. The main routes for the excretion of chromium are via kidney/urine and the bile/feces. Cr(III) is unable to enter into the cells but Cr(VI) enters through membrane anionic transporters. Intracellular Cr(VI) is metabolically reduced to Cr(III). Cr(VI) does not react with macromolecules such as DNA, RNA, proteins and lipids. However, both Cr(III) and the reductional intermediate Cr(V) are capable of co-ordinate, covalent interactions with macromolecules. Chromium is an essential nutrient required by the human body to promote the action of insulin for the utilization of sugars, proteins and fats. CrP has been used as nutritional supplement; it controls blood sugar in diabetes and may reduce cholesterol and blood pressure levels. Chromium increases insulin binding to cells, insulin receptor number and activates insulin receptor kinase leading to increased insulin sensitivity. But high doses of chromium and long term exposure of it can give rise to various, cytotoxic and genotoxic reactions that affect the immune system of the body. However, the mechanism of the Cr(VI)-induced cytotoxicity is not entirely understood. A series of in vitro and in vivo studies have demonstrated that Cr(VI) induces oxidative stress through enhanced production of reactive oxygen species (ROS) leading to genomic DNA damage and oxidative deterioration of lipids and proteins. A cascade of cellular events occur following Cr(VI)-induced oxidative stress including enhanced production of superoxide anion and hydroxyl radicals, increased lipid peroxidation and genomic DNA fragmentation, modulation of intracellular oxidized states, activation of protein kinase C, apoptotic cell death and altered gene expression. Some of the factors in determining the biological outcome of chromium exposure include the bioavailability, solubility of chromium compounds and chemical speciation, intracellular reduction and interaction with DNA. The chromium genotoxicity manifests as several types of DNA lesions, gene mutations and inhibition of macromolecular synthesis. Further, chromium exposure may lead to apoptosis, premature terminal growth arrest or neoplastic transformation. Chromium-induced tumor suppressor gene p53 and oxidative processes are some of the major factors that may determine the cellular outcome. Stud... Chromium (pronounced /?kro?mi?m/, KROH-mee-?m) is a chemical element which has the symbol Cr and atomic number 24, first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odourless, tasteless, and malleable. The name of the element is derived from the Greek word "chr?ma" (?????), meaning color, because many of its compounds are intensely colored. It was discovered by Louis Nicolas Vauquelin in the mineral crocoite (lead chromate) in 1797. Crocoite was used as a pigment, and after the discovery that the mineral chromite also contains chromium this latter mineral was used to produce pigments as well.; Chromium is a member of the transition metals, in group 6. Chromium(0) has an electronic configuration of 4s13d5, due to the lower energy of the high spin configuration. Chromium exhibits a wide range of possible oxidation states. The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +1, +4 and +5 are rare.; Chromium is a naturally occurring heavy metal found in the environment commonly in trivalent, Cr(III), and hexavalent, Cr(VI), forms. The reduction of Cr(VI) to Cr(III) results in the formation of reactive intermediates that contribute to the cytotoxicity, genotoxicity and carcinogenicity of Cr(VI)-containing compounds. The major non-occupational source of chromium for humans is food such as vegetables, meat, urban air, hip or knee prostheses and cigarettes. Cr(VI) is a widely used in industrial chemicals, extensively used in paints, metal finishes, steel including stainless steel manufacturing, alloy cast irons, chrome and wood treatment. On the contrary, Cr(III) salts such as chromium polynicotinate, chromium chloride and chromium picolinate (CrP) are used as micronutrients and nutritional supplements and have been demonstrated to exhibit a significant number of health benefits in animals and humans. Physiologically, it exists as an ion in the body.; Chromium enters the body through the lungs, gastro-intestinal tract and to a lesser extent through skin. Inhalation is the most important route for occupational exposure, whereas non-occupational exposure occurs via ingestion of chromium-containing food and water. Regardless of route of exposure Cr(III) is poorly absorbed whereas Cr(VI) is more readily absorbed. Further, absorption of Cr(VI) is poorer by oral route, it is thus not very toxic when introduced by the oral route. But chromium is very toxic by dermal and inhalation routes and causes lung cancer, nasal irritation, nasal ulcer, hypersensitivity reactions and contact dermatitis. All the ingested Cr(VI) is reduced to Cr(III) before entering in the blood stream. The main routes for the excretion of chromium are via kidney/urine and the bile/feces. Cr(III) is unable to enter into the cells but Cr(VI) enters through membrane anionic transporters. Intracellular Cr(VI) is metabolically reduced to Cr(III). Cr(VI) does not react with macromolecules such as DNA, RNA, proteins and lipids. However, both Cr(III) and the reductional intermediate Cr(V) are capable of co-ordinate, covalent interactions with macromolecules. Chromium is an essential nutrient required by the human body to promote the action of insulin for the utilization of sugars, proteins and fats. CrP has been used as nutritional supplement; Chromium is passivated by oxygen, forming a thin protective oxide surface layer. This layer is a spinel structure only a few atoms thick. It is very dense, preventing diffusion of oxygen into the underlying material. (In iron or plain carbon steels the oxygen migrates into the underlying material.) Chromium is usually plated on top of a nickel layer which may first have been copper plated. Chromium, unlike metals such as iron and nickel, does not suffer from hydrogen embrittlement. It does suffer from nitrogen embrittlement - chromium reacts with nitrogen from air and forms brittle nitrides at temperatures necessa... Chromium. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=7440-47-3 (retrieved 2024-10-18) (CAS RN: 7440-47-3). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0).
Nickel
Nickel is a solid, silver-white, hard, malleable transition metal with an atomic number of 28. It resists corrosion even at high temperatures. It is present in many alloys in widespread use, including stainless steels. It may also be present as an impurity in any alloy. Nickel is used in the production of coins, jewellery, and nickel-cadmium batteries, and as a catalyst for the hydrogenation of liquid oils to solid fats such as oleomargarine and vegetable shortening. Nickel-containing dental alloys continue to be used successfully in the provision of various forms of dental care. Many of these alloys have applications in the construction of restorations designed to remain in clinical service for many years, including crowns, fixed bridgework, and removable partial dentures. Furthermore, nickel containing alloys find extensive application in orthodontics, including metallic brackets, arch wires, bands, springs and ligature wires. Many instruments and devises, for example, endodontic instruments also contain nickel. Allergic responses are mediated through the immune system. In a sensitized individual, allergic responses can be initiated by relatively small amounts of the allergen; for example, if nickel ions are released from a nickel plated material following direct and prolonged contact with the skin. Individuals are first sensitized to the allergen. Subsequent exposures, if sufficiently high, may then result in an allergic reaction. A number of allergens are used in the clinical practice of dentistry, notably eugenol, mercury, nickel, chromium, cobalt, components of resin-based materials and a host of other chemical agents. The majority of dental allergies, including allergic responses to nickel-containing dental alloys, comprise Type IV hypersensitivity reactions, cell-mediated by T-lymphocytes. Physiologically, it exists as an ion in the body.(PMID: 17243350, 16405986). Catalyst for the hydrogenation of food fats and oils
Manganese
Manganese, also known as mn2+ or mn(ii), is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Manganese can be found in a number of food items such as oregon yampah, coconut, cauliflower, and red beetroot, which makes manganese a potential biomarker for the consumption of these food products. Manganese can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine, as well as throughout most human tissues. Manganese exists in all living species, ranging from bacteria to humans. In humans, manganese is involved in several metabolic pathways, some of which include arginine and proline metabolism, histidine metabolism, urea cycle, and triosephosphate isomerase. Manganese is also involved in several metabolic disorders, some of which include lactic acidemia, arginine: glycine amidinotransferase deficiency (AGAT deficiency), primary hyperoxaluria II, PH2, and fructose-1,6-diphosphatase deficiency. Moreover, manganese is found to be associated with alzheimers disease, multiple sclerosis, and parkinsons disease. Manganese is a non-carcinogenic (not listed by IARC) potentially toxic compound. In biology, manganese(II) ions function as cofactors for a large variety of enzymes with many functions. Manganese enzymes are particularly essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the oxygen-evolving complex of photosynthetic plants. While the element is a required trace mineral for all known living organisms, it also acts as a neurotoxin in larger amounts. Especially through inhalation, it can cause manganism, a condition in mammals leading to neurological damage that is sometimes irreversible . Indicated for use as a supplement to intravenous solutions given for Total Parenteral Nutrition (TPN). Administration helps to maintain plasma levels and to prevent depletion of endogenous stores and subsequent deficiency symptoms (DrugBank). Manganese mainly affects the nervous system and may cause behavioral changes and other nervous system effects, which include movements that may become slow and clumsy. This combination of symptoms when sufficiently severe is referred to as “manganism” (L228) (T3DB). Manganese is an essential trace nutrient in all forms of life. Physiologically, it. exists as an ion in the body. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver.
Zirconium
The action of Zirconium (Zr) on biological systems presents an enigma. It is ubiquitous, being present in nature in amounts higher than most trace elements. It is taken up by plants from soil and water and accumulated in certain tissues. The entry into animal systems in vivo is related to the mode of exposure and the concentration in the surrounding environment. Retention is initially in soft tissues and then slowly in the bone. The metal is able to cross the blood brain-barrier and is deposited in the brain and the placental barrier to enter milk. Physiologically, it exists as an ion in the body. The daily human uptake has been known to be as high as 125 mg. The level of toxicity has been found to be moderately low, both in histological and cytological studies. The toxic effects induced by very high concentrations are nonspecific in nature. Despite the presence and retention in relatively high quantities in biological systems, Zr has not yet been associated with any specific metabolic function. Very little information is available about its interaction with the compounds of the genetical systems, such as nucleic acids. Apparently, the metal is neither an essential nor toxic element in the conventional sense. However, the increasing exposure to this element through its increasing use in new materials and following radioactive fallout, has increased the importance of the study of its effects on living organisms. The tetravalent nature of the ionic state and the high stability of the compounds formed are important factors that need to be considered, as also the accumulation of this element in the brain, reminiscent of the relationship between Aluminum and Alzheimers disease. Zirconium is a metallic element with the atomic number 40 and mol wt 91.99, and belongs to the group IVB and second transition series of the fifth period of Mendeleyevs periodic table. It was named from Arabic zargun, meaning gold color. Discovered in the semiprecious gem zircon, as orthosilicate, by Klaproth in 1789, Zr was isolated as an element by Berzelius in 1824. In its metal form, Zr is hard and resistant to corrosion, heat, and acid. Zirconium behaves like an essential trace metal in the biosphere, although the possibility that it is a natural contaminant with no considerable physiological effects must be considered (PMID: 1283692, Biol Trace Elem Res. 1992 Dec;35(3):247-71.). Zirconium is a chemical element with the symbol Zr, atomic number 40 and atomic mass of 91.224. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. Five isotopes occur naturally, three of which are stable. Zirconium compounds have no biological role and are of low toxicity. The human body contains, on average, only 1 milligram of zirconium, and daily intake is approximately 50 ug per day. Zirconium content in human blood is as low as 10 parts per billion. Aquatic plants readily take up soluble zirconium, but it is rare in land plants. Seventy percent of plants have no detectable zirconium content, and those that do have as little as 5 parts per billion. [Wikipedia]. Zirconium is found in many foods, some of which are european plum, parsley, carrot, and endive.
Titanium
A metallic element, titanium is recognized for its high strength-to-weight ratio. It is a strong metal with low density that is quite ductile (especially in an oxygen-free environment), lustrous, and metallic-white in color. The relatively high melting point (over 1,649 °C or 3,000 °F) makes it useful as a refractory metal.; A more recently developed method, the FFC Cambridge process, may eventually replace the Kroll process. This method uses titanium dioxide powder (which is a refined form of rutile) as feedstock to make the end product which is either a powder or sponge. If mixed oxide powders are used, the product is an alloy manufactured at a much lower cost than the conventional multi-step melting process. The FFC Cambridge process may render titanium a less rare and expensive material for the aerospace industry and the luxury goods market, and could be seen in many products currently manufactured using aluminium and specialist grades of steel.; Due to their high tensile strength to density ratio, high corrosion resistance, and ability to withstand moderately high temperatures without creeping, titanium alloys are used in aircraft, armor plating, naval ships, spacecraft, and missiles. For these applications titanium alloyed with aluminium, vanadium, and other elements is used for a variety of components including critical structural parts, fire walls, landing gear, exhaust ducts (helicopters), and hydraulic systems. In fact, about two thirds of all titanium metal produced is used in aircraft engines and frames. The SR-71 "Blackbird" was one of the first aircraft to make extensive use of titanium within its structure, paving the way for its use in modern military and commercial aircraft. An estimated 59 metric tons (130,000 pounds) are used in the Boeing 777, 45 in the Boeing 747, 18 in the Boeing 737, 32 in the Airbus A340, 18 in the Airbus A330, and 12 in the Airbus A320. The Airbus A380 may use 146 metric tons, including about 26 tons in the engines. In engine applications, titanium is used for rotors, compressor blades, hydraulic system components, and nacelles. The titanium 6AL-4V alloy accounts for almost 50\\% of all alloys used in aircraft applications.; The metal is a dimorphic allotrope with the hexagonal alpha form changing into the body-centered cubic (lattice) ? form at 882 °C (1,620 °F). The specific heat of the alpha form increases dramatically as it is heated to this transition temperature but then falls and remains fairly constant for the ? form regardless of temperature. Similar to zirconium and hafnium, an additional omega phase exists, which is thermodynamically stable at high pressures, but is metastable at ambient pressures. This phase is usually hexagonal (ideal) or trigonal (distorted) and can be viewed as being due to a soft longitudinal acoustic phonon of the ? phase causing collapse of (111) planes of atoms.; Titanium (pronounced /ta??te?ni?m/, tye-TAY-nee-?m) is a chemical element with the symbol Ti and atomic number 22. Sometimes called the ?space age metal?, it has a low density and is a strong, lustrous, corrosion-resistant (including sea water, aqua regia and chlorine) transition metal with a silver color.; Titanium burns in air when heated to 1,200 °C (2,190 °F) and in pure oxygen when heated to 610 °C (1,130 °F) or higher, forming titanium dioxide. As a result, the metal cannot be melted in open air as it burns before the melting point is reached, so melting is only possible in an inert atmosphere or in a vacuum. It is also one of the few elements that burns in pure nitrogen gas (it burns at 800 °C or 1,472 °F and forms titanium nitride, which causes embrittlement). Titanium is resistant to dilute sulfuric acid and hydrochloric acid, along with chlorine gas, chloride solutions, and most organic acids. It is paramagnetic (weakly attracted to magnets) and has fairly low electrical and thermal conductivity.; Titanium is a light, strong, lustrous, corrosion-resistant (including resistance to sea... Titanium is a light, strong, lustrous, corrosion-resistant (including resistance to sea water and chlorine) transition metal with a white-silvery-metallic color; in the periodic table it has the symbol Ti and atomic number 22. Titanium and its alloys are used for medical purpose like osteosynthesis, arthroplasty, pacemaker encasing, orthodontical wires, or in daily-use articles like spectacle frames. At a composition of 50\\% nickel and 50\\% titanium, the material nitinol can be folded but returns at given temperatures to its original form without damage. This shape memory effect is used for spectacle frames, flexible tubes, intravascular stents, or orthodontic wires. When exposing the latter to an acidic environment, a substantial nickel and titanium release can be observed. However, even pure titanium materials used for implant alloys may contain nickel as result of the production process. Standard titanium alloys (TiAl6Nb7, TiAl6V4) and pure titanium discs supplied by five different titanium manufactures were shown to contain up to 0.034 wt \\% nickel, with iodide-titanium having the lowest percentage (0.002 wt \\%). Here, the nickel atoms are reported to be in solid solution in the titanium lattice. Suspected delayed-type hypersensitivity reactions to titanium were first reported as pacemaker dermatitis, but their existence is still put in question due to not always complete allergological work up and insufficient patch test preparations. In 1984, Peters et al. described a patient who had repeatedly cardiac pacemakers implanted and removed because pruritus, redness, and swelling of the skin overlying the pacemaker had developed within several weeks after insertion. These reactions were interpreted as contact sensitivity to the pure titanium encasing of the pacemaker, as there was a ++ patch test reaction to a thin square of metallic titanium applied with artificial sweat. Physiologically, it exists as an ion in the body. Humans exposed to titanium can develop pulmonary alveolar proteinosis (PAP, a disease of obscure cause that is characterized by the accumulation of a granular material that contains abundant lipid within the alveoli of lung.) with severe respiratory failure; analysis of particles found in lung tissues obtained by open lung biopsies demonstrated the presence of titanium. Salts of titanium are often considered to be relatively harmless but its chlorine compounds, such as TiCl2, TiCl3 and TiCl4, have unusual hazards. The dichloride takes the form of pyrophoric black crystals, and the tetrachloride is a volatile fuming liquid. All of titaniums chlorides are corrosive. (PMID: 7606971, 14756054, 16958916).
Gold
Gold is a chemical element with the symbol Au (from the Latin aurum) and atomic number 79. It is a highly sought-after precious metal which, for many centuries, has been used as money, a store of value and in jewelery. The metal occurs as nuggets or grains in rocks, underground "veins" and in alluvial deposits. It is one of the coinage metals. Gold is dense, soft, shiny and the most malleable and ductile of the known metals. Pure gold has an attractive bright yellow color. Physiologically, it exists as an ion in the body. There is increasing documentation of allergic contact dermatitis and other effects from gold jewelry, gold dental restorations, and gold implants. These effects were especially pronounced among females wearing body-piercing gold objects. One estimate of the prevalence of gold allergy worldwide is 13\\%, as judged by patch tests with monovalent organogold salts. Eczema of the head and neck was the most common response of individuals hypersensitive to gold, and sensitivity can last for at least several years. Ingestion of beverages containing flake gold can result in allergic-type reactions similar to those seen in gold-allergic individuals exposed to gold through dermal contact and other routes. Studies with small laboratory mammals and injected doses of colloidal gold showed increased body temperatures, accumulations in reticular cells, and dose enhancement in tumor therapy; gold implants were associated with tissue injuries. It is proposed that Au degrees toxicity to mammals is associated, in part, with formation of the more reactive Au+ and Au3+ species. Contact allergy to gold as demonstrated by patch testing is very common among patients with eczematous disease and seems to be even more frequent among patients with complaints from the oral cavity. There is a positive correlation between gold allergy and the presence of dental gold. Gold allergy is often found in patients with non-specific stomatitides as well as in those with lichenoid reactions or with only subjective symptoms from the oral cavity. The therapeutic effect of substituting other dental materials for gold alloys is conspicuous in casuistic reports but less impressive in larger patient materials. The amount of dental gold is correlated qualitatively and quantitatively to the blood level of gold and the effects if any of circulating blood gold are unknown. There is clearly a need for prospective studies in the field and gold sodium thiosulfate is considered an important item in the dental series for patch testing. (PMID: 15258315, 12423401). It is used in food decoration and colouring especies in Europe. Not permitted for food use in U.S.A. Gold is found in many foods, some of which are cashew nut, common hazelnut, coconut, and pistachio.
Tantalum
Ta (180.948014)
Tantalum is a transition metal (atomic number 73; atomic weight 180.05) that remains relatively inert in vivo. Dating back to the mid-1900s multiple medical devices have been fabricated that utilize this material, including: pacemaker electrodes, foil and mesh for nerve repair, radiopaque markers, and cranioplasty plates. Tantalum-based implants have displayed an exceptional biocompatibility and safety record in orthopedic, cranio-facial, and dentistry literature. The basic structure of this porous tantalum metal yields a high volumetric porosity, a low modulus of elasticity, and relatively high frictional characteristics.; Tantalum is known to be relatively inert in vivo and is now used as plates, sutures, radio-markers, and prostheses covering a wide variety of medical subspecialties and procedures. Dental implants have yielded excellent 8-year follow-up with tantalum-based components used for osseous anchorage. The oxide formed on the surface of tantalum implants (self-passivation) in vivo has been found to be quite stable over a wide range of pH and potential ranges. On high-resolution examination, titanium was found to have no multi-nucleated macrophages in the tissue surrounding the metallic implant, while tantalum implants displayed an occasional peri-implant macrophage. Physiologically, it ; exists as an ion in the body.; Overall porous tantalum is corrosion resistant, may be associated with less peri-implant stress shielding, and has the potential to allow for immediate weight bearing (given its high frictional characteristics). These inherent properties and proven biocompatibility make porous tantalum an intriguing metal for the design and manufacture of: press-fit or cementless components for total joint arthroplasty, bone graft substitute, or a scaffold for potential cartilage resurfacing. (PMID: 16737737). Tantalum is found in many foods, some of which are orange bell pepper, green bell pepper, yellow zucchini, and common hazelnut. Tantalum is a transition metal (atomic number 73; atomic weight 180.05) that remains relatively inert in vivo. Dating back to the mid-1900s multiple medical devices have been fabricated that utilize this material, including: pacemaker electrodes, foil and mesh for nerve repair, radiopaque markers, and cranioplasty plates. Tantalum-based implants have displayed an exceptional biocompatibility and safety record in orthopedic, cranio-facial, and dentistry literature. The basic structure of this porous tantalum metal yields a high volumetric porosity, a low modulus of elasticity, and relatively high frictional characteristics. Tantalum is known to be relatively inert in vivo and is now used as plates, sutures, radio-markers, and prostheses covering a wide variety of medical subspecialties and procedures. Dental implants have yielded excellent 8-year follow-up with tantalum-based components used for osseous anchorage. The oxide formed on the surface of tantalum implants (self-passivation) in vivo has been found to be quite stable over a wide range of pH and potential ranges. On high-resolution examination, titanium was found to have no multi-nucleated macrophages in the tissue surrounding the metallic implant, while tantalum implants displayed an occasional peri-implant macrophage. Physiologically, it exists as an ion in the body. Overall porous tantalum is corrosion resistant, may be associated with less peri-implant stress shielding, and has the potential to allow for immediate weight bearing (given its high frictional characteristics). These inherent properties and proven biocompatibility make porous tantalum an intriguing metal for the design and manufacture of: press-fit or cementless components for total joint arthroplasty, bone graft substitute, or a scaffold for potential cartilage resurfacing. (PMID: 16737737).
Yttrium
Yttrium, also known as 39y or ytrio, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Yttrium can be found in a number of food items such as cucumber, italian sweet red pepper, turnip, and red beetroot, which makes yttrium a potential biomarker for the consumption of these food products. Yttrium can be found primarily in cerebrospinal fluid (CSF) and saliva. Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals, and is never found in nature as a free element. 89Y is the only stable isotope, and the only isotope found in the Earths crust . An element of the rare earth family of metals. It has the atomic symbol Y, atomic number 39, and atomic weight 88.91. In conjunction with other rare earths, yttrium is used as a phosphor in television receivers and is a component of the yttrium-aluminum garnet (YAG) lasers.
Ruthenium
Ruthenium, also known as ru, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Ruthenium can be found in a number of food items such as italian sweet red pepper, broccoli, potato, and dill, which makes ruthenium a potential biomarker for the consumption of these food products. Ruthenium can be found primarily in blood, cerebrospinal fluid (CSF), and urine. Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals. The Russian-born scientist of Baltic-German ancestry and a member of the Russian Academy of Science Karl Ernst Claus discovered the element in 1844 at Kazan State University in Russia and named it after the Latin name of his homeland, Rus. Ruthenium is usually found as a minor component of platinum ores; the annual production is about 20 tonnes. Most ruthenium produced is used in wear-resistant electrical contacts and thick-film resistors. A minor application for ruthenium is in platinum alloys and as a chemistry catalyst . A polyvalent hard white metal, ruthenium is a member of the platinum group. Like the other metals of the platinum group, ruthenium is inert to most chemicals. Most ruthenium is used for wear-resistant electrical contacts and the production of thick-film resistors. A minor application of ruthenium is its use in some platinum alloys.[Wikipedia]
Palladium
Pd (105.903475)
Palladium, also known as pd or paladio, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Palladium can be found in a number of food items such as parsnip, potato, cucumber, and green zucchini, which makes palladium a potential biomarker for the consumption of these food products. Palladium can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine. Palladium is a non-carcinogenic (not listed by IARC) potentially toxic compound. More than half the supply of palladium and its congener platinum is used in catalytic converters, which convert as much as 90\\% of the harmful gases in automobile exhaust (hydrocarbons, carbon monoxide, and nitrogen dioxide) into less noxious substances (nitrogen, carbon dioxide and water vapor). Palladium is also used in electronics, dentistry, medicine, hydrogen purification, chemical applications, groundwater treatment, and jewelry. Palladium is a key component of fuel cells, which react hydrogen with oxygen to produce electricity, heat, and water . Palladium may be absorbed through oral, dermal, and inhalation exposure. Once in the body it distributes to the kidney, liver, spleen, lymph nodes, adrenal gland, lung and bone. Palladium and its metabolites are excreted in the urine and faeces (A21) (T3DB). Palladium is a rare and lustrous silvery-white metal. Palladium has the lowest melting point and is the least dense of platinum group metals. The primary use for palladium is in catalytic converters for the automotive industry.
Platinum
Pt (194.964785)
Platinum, also known as pt, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Platinum can be found in a number of food items such as white cabbage, sunburst squash (pattypan squash), potato, and broccoli, which makes platinum a potential biomarker for the consumption of these food products. Platinum can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequently, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the alluvial sands of various rivers, it was first used by pre-Columbian South American natives to produce artifacts. It was referenced in European writings as early as 16th century, but it was not until Antonio de Ulloa published a report on a new metal of Colombian origin in 1748 that it began to be investigated by scientists . Platinum is a rare, dense, malleable, ductile, precious, gray-white transition metal, that is highly resistant to corrosion. Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry.
Rhenium
Re (186.955765)
Its usual commercial form is a powder, but this element can be consolidated by pressing and sintering in a vacuum or hydrogen atmosphere. This procedure yields a compact solid having a density above 90\\% of the density of the metal. When annealed this metal is very ductile and can be bent, coiled, or rolled. Rhenium-molybdenum alloys are superconductive at 10 K; tungsten-rhenium alloys are also superconductive around 4-8 K, depending on the alloy. Rhenium metal superconducts at 2.4 K. Methylrhenium trioxide ("MTO"), CH3ReO3 is a volatile, colourless solid has been used as a catalyst in some laboratory experiments. It can be prepared by many routes, a typical method is the reaction of Re2O7 and tetramethyltin:; Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earths crust. The free element has the third-highest melting point and highest boiling point of any element. Rhenium resembles manganese chemically and is obtained as a by-product of molybdenum and copper refinement. Rhenium shows in its compounds a wide variety of oxidation states ranging from 1 to +7. Rhenium diboride (ReB2) is a hard compound having the hardness similar to that of tungsten carbide, silicon carbide, titanium diboride or zirconium diboride. Rhenium has a stable isotope, rhenium-185, which nevertheless occurs in minority abundance, a situation found only in one other element (indium). Naturally occurring rhenium is 37.4\\% 185Re, which is stable, and 62.6\\% 187Re, which is unstable but has a very long half-life (~1010 years). This lifetime is affected by the charge state of rhenium atom. The beta decay of 187Re is used for rhenium-osmium dating of ores. The available energy for this beta decay (2.6 keV) is one of the lowest known among all radionuclides. There are twenty-six other recognized radioactive isotopes of rhenium. Rhenium in the form of rhenium-platinum alloy is used as catalyst for catalytic reforming, which is a chemical process to convert petroleum refinery naphthas with low octane ratings into high-octane liquid products. Worldwide, 30\\% of catalysts used for this process contain rhenium. The olefin metathesis is the other reaction for which rhenium is used as catalyst. Normally Re2O7 on alumina is used for this process. Rhenium catalysts are very resistant to chemical poisoning from nitrogen, sulfur and phosphorus, and so are used in certain kinds of hydrogenation reactions. Rhenium is a silvery-white metal with one of the highest melting points of all elements, exceeded by only tungsten and carbon. It is also one of the densest, exceeded only by platinum, iridium and osmium. Rhenium has a hexagonal close-packed crystal structure, with lattice parameters a = 276.1 pm and c = 445.6 pm. Rhenium is one of the rarest elements in Earths crust with an average concentration of 1 ppb; other sources quote the number of 0.5 ppb making it the 77th most abundant element in Earths crust. Rhenium is probably not found free in nature (its possible natural occurrence is uncertain), but occurs in amounts up to 0.2\\% in the mineral molybdenite (which is primarily molybdenum disulfide), the major commercial source, although single molybdenite samples with up to 1.88\\% have been found. Chile has the worlds largest rhenium reserves, part of the copper ore deposits, and was the leading producer as of 2005. It was only recently that the first rhenium mineral was found and described (in 1994), a rhenium sulfide mineral (ReS2) condensing from a fumarole on Russias Kudriavy volcano, Iturup island, in the Kurile Islands. Kudryavy discharges up to 20-60 kg rhenium per year mostly in the form of rhenium disulfide. Named rheniite, this rare mineral commands high prices among collectors. Rhenium, also known as 75re or renio, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Rhenium can be found in a number of food items such as dill, yellow zucchini, romaine lettuce, and green zucchini, which makes rhenium a potential biomarker for the consumption of these food products. Rhenium can be found primarily in urine. Rhenium is a chemical element with symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earths crust. Rhenium has the third-highest melting point and second-highest boiling point of any element at 5903 K. Rhenium resembles manganese and technetium chemically and is mainly obtained as a by-product of the extraction and refinement of molybdenum and copper ores. Rhenium shows in its compounds a wide variety of oxidation states ranging from −1 to +7 .
Hafnium
Hafnium, also known as 72hf or hafnio, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Hafnium can be found in a number of food items such as common hazelnut, almond, cucumber, and spinach, which makes hafnium a potential biomarker for the consumption of these food products. Hafnium can be found primarily in saliva and urine. Hafnium is a chemical element with symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, by Coster and Hevesy, making it the last stable element to be discovered. Hafnium is named after Hafnia, the Latin name for Copenhagen, where it was discovered . Hafnium is a chemical element with the symbol Hf and atomic number 72. Hafnium is used in filaments and electrodes. Some semiconductor fabrication processes use its oxide for integrated circuits at 45 nm and smaller feature lengths. Some superalloys used for special applications contain hafnium in combination with niobium, titanium, or tungsten.
Niobium
Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology: Niobe, daughter of Tantalus.
Scandium
Scandium, also known as 21sc or escandio, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Scandium can be found in a number of food items such as butternut, common hazelnut, coconut, and cashew nut, which makes scandium a potential biomarker for the consumption of these food products. Scandium is present in most of the deposits of rare-earth and uranium compounds, but it is extracted from these ores in only a few mines worldwide. Because of the low availability and the difficulties in the preparation of metallic scandium, which was first done in 1937, applications for scandium were not developed until the 1970s. The positive effects of scandium on aluminium alloys were discovered in the 1970s, and its use in such alloys remains its only major application. The global trade of scandium oxide is about 10 tonnes per year .
Osmium
Os (191.960603)
Osmium, also known as 76os or osmio, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Osmium can be found in a number of food items such as garlic, dill, sunburst squash (pattypan squash), and green zucchini, which makes osmium a potential biomarker for the consumption of these food products. Osmium (from Greek ὀσμή osme, "smell") is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with a density of 22.59 g/cm3. Its alloys with platinum, iridium, and other platinum-group metals are employed in fountain pen nib tipping, electrical contacts, and other applications where extreme durability and hardness are needed .
Iridium
Ir (192.962942)
Iridium, also known as 77ir or iridio, is a member of the class of compounds known as homogeneous transition metal compounds. Homogeneous transition metal compounds are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom. Iridium can be found in cucumber, which makes iridium a potential biomarker for the consumption of this food product. The most important iridium compounds in use are the salts and acids it forms with chlorine, though iridium also forms a number of organometallic compounds used in industrial catalysis, and in research. Iridium metal is employed when high corrosion resistance at high temperatures is needed, as in high-performance spark plugs, crucibles for recrystallization of semiconductors at high temperatures, and electrodes for the production of chlorine in the chloralkali process. Iridium radioisotopes are used in some radioisotope thermoelectric generators .