Alkuaineiden jaksollisen järjestelmän VIII ryhmä muodostuu kolmen alkuaineen muodostamasta ryhmästä, ns. triadista, joista ensimmäisen, rautaryhmän, muodostavat metallit rauta (Fe) , koboltti(Co) ja nikkeli (Ni) .niiden elektronirakennelmat ovat keskenään samankaltaiset ulkokuoreen nähden. Ne ovat siirtymäalkuaineita (seuraavan sisemmän kuoren d-orbitaalin vajavainen täyttyminen). Niiden metallien hapetusluku on +2 silloin, kun ne luovuttavat ulloimman kuoren s- elektronit. Sisemmän kuoren d- elektronien vaikutuksesta näillä metalleilla voi olla muitakin hapetusasteita. Rautaryhmän metallien väliset ominaisuudet johtuvat yleensä näistä d-elektroneista. Rauta eroaa monilta ominaisuuksiltaan koboltista ja nikkelistä ja niihin verrattuna sillä on paljon tärkeämpi käytännöllinen merkitys.
Kemiallisissa yhdisteissä rautaryhmän metallien pääasialliset hapetusluvut ovat +2 ja +3. Hapetusluvun +3 saavuttaa vaikeimmin koboltti ja helpoimmin rauta: (rauta(III), ferriyhdisteet.
Rauta (II) yhdisteet ovat ferroyhdisteitä.
Kts teksti rauta.
http://en.wikipedia.org/wiki/Cobalt
Cobalamiini on koboltin orgaaninen muoto . ihminen ei syntetisoi kobalamiinia joten koboltin tarvetta ei sinänsä ole varsinaisena alkuaineena, luulisi ainakin. Se on my.ös epäorgaanisena myrkyllinen. Kobalamiinissa se on erittäin tiukasti kiinni neljällä koordinaatiosidoksella rengasrakenteen pyrrolien typpiatomeihin, joten se erittynee kehosta regnasrakenteen erittyessä eikä hajoa erikseen renkaasta.
Katso pohdinta Essentiellit ultrahivenaineet. Näihin lasketaan nikkeli (Ni) nettitiedon mukaan.
http://en.wikipedia.org/wiki/Nickel
Tekstejä nikkelin merkityksestä:
http://www.ncbi.nlm.nih.gov/pubmed/6398286
ultratrace elements
http://www.ncbi.nlm.nih.gov/pubmed/3900311
Päivitystä 16.1. 2012
KOBOLTISTA TIETOA PUBMED hausta:
Kemiallisissa yhdisteissä rautaryhmän metallien pääasialliset hapetusluvut ovat +2 ja +3. Hapetusluvun +3 saavuttaa vaikeimmin koboltti ja helpoimmin rauta: (rauta(III), ferriyhdisteet.
Rauta (II) yhdisteet ovat ferroyhdisteitä.
Kts teksti rauta.
- Onko koboltti ja nikkeli essentiellejä?
http://en.wikipedia.org/wiki/Cobalt
Cobalamiini on koboltin orgaaninen muoto . ihminen ei syntetisoi kobalamiinia joten koboltin tarvetta ei sinänsä ole varsinaisena alkuaineena, luulisi ainakin. Se on my.ös epäorgaanisena myrkyllinen. Kobalamiinissa se on erittäin tiukasti kiinni neljällä koordinaatiosidoksella rengasrakenteen pyrrolien typpiatomeihin, joten se erittynee kehosta regnasrakenteen erittyessä eikä hajoa erikseen renkaasta.
- Koboltin toksisuudesta artikkeli.
Cell Biol Toxicol. 2017 Jun 27. doi: 10.1007/s10565-017-9402-0. [Epub ahead of print] Cobalt inhibits motility of axonal mitochondria and induces axonal degeneration in cultured dorsal root ganglion cells of rat. Kikuchi S1, Ninomiya T2, Kohno T3, Kojima T3, Tatsumi H2.
Abstract . Cobalt is a trace element that localizes in the human body as cobalamin,
also known as vitamin B12. Excessive cobalt exposure induces a
peripheral neuropathy, the mechanisms of which are yet to be elucidated.
We investigated how cobalt may affect mitochondrial motility in primary cultures of rat dorsal root ganglion (DRG). We observed mitochondrial motility by time-lapse imaging after DsRed2 tagging via lentivirus, mitochondrial structure using transmission electron microscopy (TEM), and axonal swelling using immunocytochemical staining. The concentration of cobaltous ion (Co2+) required to significantly suppress mitochondrial motility is lower than that required to induce axonal swelling following a 24-h treatment. Exposure to relatively low concentrations of Co2+ for 48 h suppressed mitochondrial motility without leading to axonal swelling. TEM images indicated that Co2+ induces mitochondrial destruction. Our results show that destruction of the axonal mitochondria precedes the axonal degeneration induced by Co2+ exposure.KEYWORDS:
We investigated how cobalt may affect mitochondrial motility in primary cultures of rat dorsal root ganglion (DRG). We observed mitochondrial motility by time-lapse imaging after DsRed2 tagging via lentivirus, mitochondrial structure using transmission electron microscopy (TEM), and axonal swelling using immunocytochemical staining. The concentration of cobaltous ion (Co2+) required to significantly suppress mitochondrial motility is lower than that required to induce axonal swelling following a 24-h treatment. Exposure to relatively low concentrations of Co2+ for 48 h suppressed mitochondrial motility without leading to axonal swelling. TEM images indicated that Co2+ induces mitochondrial destruction. Our results show that destruction of the axonal mitochondria precedes the axonal degeneration induced by Co2+ exposure.KEYWORDS:
Axonal swelling; Cobalt; Mitochondria; Peripheral nerve
- Kobolttia käytetään isotooppitutkimuksissa ja syöpähoidossa.
Katso pohdinta Essentiellit ultrahivenaineet. Näihin lasketaan nikkeli (Ni) nettitiedon mukaan.
http://en.wikipedia.org/wiki/Nickel
Tekstejä nikkelin merkityksestä:
http://www.ncbi.nlm.nih.gov/pubmed/6398286
ultratrace elements
http://www.ncbi.nlm.nih.gov/pubmed/3900311
Päivitystä 16.1. 2012
KOBOLTISTA TIETOA PUBMED hausta:
J Toxicol Clin Toxicol. 1999;37(2):201-6.Cobalt.
Abstract Cobalt is a relatively rare magnetic element with properties similar to iron and nickel. The two valance states are cobaltous (II) and cobaltic (III) and the former is the most common valance used in the chemical industry. Cobalt occurs in nature primarily as arsenides, oxides, and sulfides. Most of the production of cobalt involves the metallic form used in the formation of cobalt superalloys. The term "hard metal" refers to compounds containing tungsten carbide (80-95%) combined with matrices formed from cobalt (5-20%) and nickel (0-5%).
For the general population, the diet is the main source of exposure to cobalt.
In the occupational setting, exposure to cobalt alone occurs primarily during the production of cobalt powders. In other industrial exposures (e.g., hard metal, diamond polishing), additional agents (tungsten) modulate the toxicity of cobalt. Cobalt is an essential element necessary for the formation of vitamin B12 (hydroxocobalamin); however, excessive administration of this trace element produces goiter and reduced thyroid activity.
In 1966, the syndrome "beer drinker's cardiomyopathy" appeared in Quebec City, Canada, and was characterized by pericardial effusion, elevated hemoglobin concentrations, and congestive heart failure. An interstitial pulmonary fibrosis has been associated with industrial exposure to hard metal dust (tungsten and cobalt), but not to cobalt alone. Exposure to cobalt alone produces an allergic contact dermatitis and occupational asthma. Treatment of cobalt toxicity is primarily supportive.
KOBOLTIN ISOTOOPIT
https://education.jlab.org/itselemental/iso027.html
For the general population, the diet is the main source of exposure to cobalt.
In the occupational setting, exposure to cobalt alone occurs primarily during the production of cobalt powders. In other industrial exposures (e.g., hard metal, diamond polishing), additional agents (tungsten) modulate the toxicity of cobalt. Cobalt is an essential element necessary for the formation of vitamin B12 (hydroxocobalamin); however, excessive administration of this trace element produces goiter and reduced thyroid activity.
In 1966, the syndrome "beer drinker's cardiomyopathy" appeared in Quebec City, Canada, and was characterized by pericardial effusion, elevated hemoglobin concentrations, and congestive heart failure. An interstitial pulmonary fibrosis has been associated with industrial exposure to hard metal dust (tungsten and cobalt), but not to cobalt alone. Exposure to cobalt alone produces an allergic contact dermatitis and occupational asthma. Treatment of cobalt toxicity is primarily supportive.
KOBOLTIN ISOTOOPIT
https://education.jlab.org/itselemental/iso027.html
- Päivitystä 25.10.2017
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