80 research outputs found
Effective meson masses, effective meson-nucleon couplings and neutron star radii
Using the generalized mean field theory, we have studied the relation among
the effective meson masses, the effective meson-nucleon couplings and the
equation of state (EOS) in asymmetric nuclear matter. If the effective
omega-meson mass becomes smaller at high density, the EOS becomes stiffer.
However, if we require that the omega-meson mean field is proportional to the
baryon density, the effective omega-nucleon coupling automatically becomes
smaller at the same time as the effective omega-meson mass becomes smaller.
Consequently, the EOS becomes softer. A similar relation is found for the
effective rho-meson mass and the effective rho-nucleon coupling. We have also
studied the relation among the effective meson masses, the effective
meson-nucleon couplings and a radius R of a neutron star. The R depends
somewhat on the value of the effective omega-meson mass and the effective
omega-nucleon coupling.Comment: 29pages, 24 figure
CONTAMINATION BY ARSENIC AND LEAD IN RESIDENTS FROM VIETNAM
Joint Research on Environmental Science and Technology for the Eart
Arsenic contamination in groundwater and residents from Ha Nam and Ha Tay Provinces of Red River Delta, Vietnam
Joint Research on Environmental Science and Technology for the Eart
Identification of the Transcriptional Regulator NcrB in the Nickel Resistance Determinant of Leptospirillum ferriphilum UBK03
The nickel resistance determinant ncrABCY was identified in Leptospirillum ferriphilum UBK03. Within this operon, ncrA and ncrC encode two membrane proteins that form an efflux system, and ncrB encodes NcrB, which belongs to an uncharacterized family (DUF156) of proteins. How this determinant is regulated remains unknown. Our data indicate that expression of the nickel resistance determinant is induced by nickel. The promoter of ncrA, designated pncrA, was cloned into the promoter probe vector pPR9TT, and co-transformed with either a wild-type or mutant nickel resistance determinant. The results revealed that ncrB encoded a transcriptional regulator that could regulate the expression of ncrA, ncrB, and ncrC. A GC-rich inverted repeat sequence was identified in the promoter pncrA. Electrophoretic mobility shift assays (EMSAs) and footprinting assays showed that purified NcrB could specifically bind to the inverted repeat sequence of pncrA in vitro; this was confirmed by bacterial one-hybrid analysis. Moreover, this binding was inhibited in the presence of nickel ions. Thus, we classified NcrB as a transcriptional regulator that recognizes the inverted repeat sequence binding motif to regulate the expression of the key nickel resistance gene, ncrA
GFP-tagged multimetal-tolerant bacteria and their detection in the rhizosphere of white mustard
The introduction of rhizobacteria that tolerate heavy metals is a promising approach to support plants involved in phytoextraction and phytostabilisation. In this study, soil of a metal-mine wasteland was analyzed for the presence of metal-tolerant bacterial isolates, and the tolerance patterns of the isolated strains for a number of heavy metals and antibiotics were compared. Several of the multimetal-tolerant strains were tagged with a broad host range reporter plasmid (i.e. pPROBE-NT) bearing a green fluorescent protein marker gene (gfp). Overall, the metal-tolerant isolates were predominately Gram-negative bacteria. Most of the strains showed a tolerance to five metals (Zn, Cu, Ni, Pb and Cd), but with differing tolerance patterns. From among the successfully tagged isolates, we used the transconjugant Pseudomonas putida G25 (pPROBE-NT) to inoculate white mustard seedlings. Despite a significant decrease in transconjugant abundance in the rhizosphere, the gfp-tagged cells survived on the root surfaces at a level previously reported for root colonisers
Direct imaging of glycans in Arabidopsis roots via click labeling of metabolically incorporated azido-monosaccharides
Chemical and Biochemical Properties of Oxisols after Sewage Sludge Application for 16 Years
Effects of Plant Litter Type and Additions of Nitrogen and Phosphorus on Bacterial Community-Level Physiological Profiles in a Brown Forest Soil
ArticleMICROBES AND ENVIRONMENTS. 24(1):68-71 (2009)journal articl
Is arsenobetaine the major arsenic compound in the liver of birds, marine mammals, and sea turtles?
Concentrations of total arsenic and individual arsenic compounds were determined in the livers of birds, marine
mammals, and sea turtles by using hydride generation-atomic absorption spectrometry (HG-AAS) and high performance
liquid chromatography/inductively coupled plasma-mass spectrometry (HPLC/ICP-MS). Marine mammals feeding on
cephalopods and crustaceans accumulated higher arsenic concentrations than the species feeding on fishes. No significant
age and gender differences in arsenic concentrations were observed for most of the species of marine mammals. Elevated
total arsenic concentrations were found in livers of black-footed albatross and loggerhead turtles and these values were
comparable to those of lower trophic marine animals. Arsenobetaine was the major arsenical in the livers of most of the
species examined. Particularly, in seabirds, mean proportions of arsenobetaine was more than 90% of total extractable
arsenic In contast, arsenobetaine was a minor constituent in dugong. The compositions of arsenic compounds were
different among the species examined. These results might be due to the differences in the metabolic capacity among
species and/or the different compositions of arsenic compounds in their preys
Comparative study of mercury in liver and muscle of Dall's porpoise (Phocoenoides dalli) off Sanriku coast of Japan
Liver and muscle samples of 22 Dall's porpoises (Phocoenoides
dalli) collected off Sanriku coast of Japan were analyzed to compare the
bioaccumulation of total mercury (Hg) and organic mercury (OrgHg).
Concentrations of Hg and OrgHg in the liver were significantly higher than
those in the muscle. In the liver evident detoxification effect of Hg was
suggested by that concentrations of Hg were usually much higher than those
of OrgHg. In the muscle such effect was limited as Hg concentrations were
closed to those of OrgHg
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