The discovery (Smith, 1948; Rickes, Brink, Koniuszy, Wood & Folkers, 1948) that vitamin B,, contains cobalt immediately suggested that it might be possible to label the molecule with radioactive cobalt. A radioactive form of the vitamin would be invaluable for many biochemical investigations. However, as was rather to be anticipated from earlier experiments (Flagg, 1941; McCallum & Hoshowsky, 1...

BACKGROUND In diverse organisms, adaptation to low oxygen (hypoxia) is mediated through complex gene expression changes that can, in part, be mimicked by exposure to metals such as cobalt. Although much is known about the transcriptional response to hypoxia and cobalt, little is known about the all-important cell metabolism effects that trigger these responses. METHODS AND FINDINGS Herein we ...

Processes that enable marine phytoplankton to acquire trace metals are fundamental to our understanding of primary productivity and global carbon biogeochemical cycling. Here we show that the abundant marine cyanobacterium, Prochlorococcus strain MED4-Ax, has an absolute cobalt requirement and that zinc cannot substitute for cobalt in the growth medium, as is the case in some other phytoplankto...

The use of cobalt dinitrosoalkane complexes in the C-H functionalization of alkenes has been demonstrated. Reaction of a series of alkenes with Me4CpCo(CO)2 in the presence of NO generates intermediate cobalt dinitrosoalkane complexes that can be deprotonated alpha to the nitrosyl group and added to various Michael acceptors. The resultant products can then undergo retrocycloaddition reactions ...

We have reviewed 70 patients with bilateral simultaneous total hip arthroplasties to determine the rate of failure and to compare polyethylene wear and osteolysis between an implant with a cobalt-chrome head and Hylamer liner with that of a zirconia head and Hylamer liner. The mean thickness of the polyethylene liner was 11.0 mm (8.8 to 12.2) in the hip with a zirconia head and 10.7 mm (8.8 to ...

Background: Cobalt (Co) is an essential trace element for mammals required for the synthesis of vitamin B12. It is not a cumulative toxin but chronic exposure induces negative effects on the organism. It was proven that cobalt passes via placenta appearing in the fetal blood and amniotic fluid and it is shown to possess an embryotoxic effect. Also, chromium (Cr) is recognized as a trace element...

sphere-like shaped cobalt oxide nanoparticles (co3o4) were synthesized by a simple wet chemical method using cobalt chloride as precursor and cetyl trimethylammonium bromide (ctab) as surfactant. their structural and surface morphologial properties were characterized by high resolution transmission electron microscopy (hrtem), field emission scanning electron microscopy (fesem) and x-ray diffra...

The protective effects of cobalt on potato seedling leaves during osmotic stress were reported and discussed in this paper. The results showed that the membrane damage was significantly alleviated after 24 h of osmotic stress when cobalt of appropriate concentrations was added in PEG solutions. During -1.0 MPa PEG osmotic stress cobalt of 25 μmol L inhibited ethylene production rate significant...

BACKGROUND Since 1997, Fallon, Nevada, has experienced a cluster of childhood leukemia that has been declared "one of the most unique clusters of childhood cancer ever reported." Multiple environmental studies have shown airborne tungsten and cobalt to be elevated within Fallon, but the question remains: Have these metals changed through time in correspondence with the onset of the leukemia clu...

BACKGROUND Failed hip prostheses can cause elevated circulating cobalt and chromium levels, with rare reports of fatal systemic organ deposition, including cobalt cardiomyopathy. Although blood cobalt and chromium levels are easily measured, organ deposition is difficult to detect without invasive biopsy. The T2* magnetic resonance (MR) method is used to quantify tissue iron deposition, and pla...