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1.
Ranganathan Santhanam 《Inorganica chimica acta》2008,361(2):473-478
A novel method of preparation of hexahydroaluminate complexes M3AlH6 (M = Li, Na or K) from the corresponding alkali metal hydride and tetrahydroaluminate has been explored, using dimethyl ether (Me2O) as a solvent at near-ambient temperatures. The results are compared with those obtained using a recently established mechanochemical approach. Characterization of the products by powder X-ray diffraction revealed M3AlH6 to be formed in high yield for M = Li and Na, but not for M = K. The attempted preparation of Li2NaAlH6 and Li2KAlH6 was unsuccessful. 相似文献
2.
Metals such as Cu2+, Fe3+, and Zn2+ are major contributors to the biology of a brain in stages of health, aging, and disease because of their unique effects on both protein structures (misfolding) and oxidative stress. The relationship between metal ions and neurodegenerative diseases is very complicated. Our study highlights how metal ions influence amyloid formation at low pH and on preformed amyloid fibrils. By using thioflavin T assay, ANS fluorescence, Congo red assay, circular dichroism, and microscopy to elucidate the effects of Cu2+, Fe3+, and Zn2+ on goat brain cystatin (GBC) aggregation at low pH. Results showed that Cu2+ and Fe3+ inhibit fibril formation of GBC by promoting amorphous aggregates. However, Zn2+ exclusively promotes fibril formation at low pH, leading to the formation of more ordered aggregates. Furthermore, the combined results of these complementary methods also suggested that Cu2+ and Fe3+ destabilize the β-sheet secondary structure of preformed amyloid fibrils of GBC. 相似文献
3.
Janitha A. Liyanage David M. Taylor David R. Williams 《Chemical Speciation and Bioavailability》2013,25(2):73-75
ABSTRACTA method has been developed for impregnating alginate-based wound dressings with trace elements required for wound healing and for quantifying the transfer from these dressing to wound fluid (for which a substitute—blood serum—was used in these experiments). Under ideal conditions, up to 85% can be carried across from the tow to the wound fluid. 相似文献
4.
Abstract: The effect of timing of application on the incompatibility of three fungicides (metalaxyl, mancozeb, copper oxide) and isolate MK2001 of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin was assessed in vitro . Isolate MK 2001 at 1 × 107 conidia/ml concentration was highly pathogenous to adults of Lygus lineolaris (Hemiptera) (84% mortality at day 4 post-treatment). The fungicides at the manufacturer recommended rate (1X) were strongly fungistatic and inhibited the fungal isolate radial growth on Sabouraud dextrose agar (SDA). Mancozeb, metalaxyl and copper oxide exhibited insecticidal activity of 24, 40 and 48% respectively, on L. lineolaris adults. It is clear that application of the fungal isolate MK2001 2–4 days before applying fungicides metalaxyl, mancozeb or copper oxide synergized the insecticidal effect of the isolate. On the contrary, application of metalaxyl, mancozeb, copper oxide 2–4 days before applying isolate MK2001 antagonized the insecticidal effect. The simultaneous use of each fungicide (metalaxyl, mancozeb or copper oxide) and the isolate gave lesser insect mortality. This study revealed that although some fungicides are incompatible for use alongside fungal isolates, the proper evaluation of their time of use could be beneficial in biological control or IPM programmes. Furthermore, the application of B. bassiana isolate MK2001 followed by fungicide application could synergize insecticidal activity. 相似文献
5.
Blood was obtained from 564 11-yr-old children who had participated since birth in a multidisciplinary health and development
study. Serum zinc concentration did not differ between the boys and the girls (mean±SD: 91=17 μg/100 mL,n=453). Five-6% of serum zinc values were low; although there was a weak correlation with height, none of the boys with low
values were below the 10th percentile for height for this group. Serum copper concentration (112±24 μg/100 mL,n=454) was unrelated to sex, height, weight, body mass index, socioeconomic status (SES), or iron status. Blood selenium concentration
(49±10 ng/mL,n=564) was lower than previously reported for Dunedin children; it was higher in children in the lower SES categories. The
data represent normal values for healthy, 11-yr-old NZ children. 相似文献
6.
A particle-induced X-ray emission (PIXE) analysis method is presented, which allows measurement of eight elements (i.e., K,
Ca, Mn, Fe, Cu, Zn, Se, and Rb) in human brain samples of only a few mg dry weight. The precision and accuracy of the method
were investigated by analyzing animal brain matter with both PIXE and instrumental neutron activation analysis (INAA). The
method was applied to measure the 8 elements in 46 different regions of 3 human brains. The sections analyzed originated from
either the left or the right cerebral hemisphere, brain stem, and cerebellum. For one of the brains, sections were also analyzed
from 26 corresponding regions of both hemispheres. For all elements, similar concentrations were found in the corresponding
areas of the left and right sides of the brain. The concentrations (in μg/g dry weight) of the elements K, Fe, Cu, Zn, Se,
and Rb were consistently higher in cortical structures than in white matter. Deep nuclei and brain stem, which have a mixed
composition, showed intermediate values for K, Zn, Se, and Rb. A hierarchical cluster analysis indicated that the various
brain regions clustered into two large groups, one comprising gray and mixed matter regions and the other, white and mixed
matter brain areas. 相似文献
7.
8.
Rice (IR 42) was grown on two soils differing in zinc status for 30 days with and without Zn under submerged conditions in
pots. The fate of soil zinc was characterized by extraction of the soil successively with copper acetate and sodium hypochlorite
and by EUF extraction. Most of the applied zinc was extracted by copper acetate and represented as complexed fraction. There
exists a close and significnat relation between Cu(OAc)2-extractable zinc and Zn extracted by EUF for 5 minutes at 50 volts (r=0.98). The EUF-extractable zinc and Cu(OAc)2-extractable zinc were significantly correlated with the zinc content in the plant (r=0.82). The data from this investigation
suggest the possibility of Zn fractionation with the EUF technique and the fractions obtained agree closely to those determined
by chemical methods. The results obtained indicate that Zn in soil is held by weak organic bonding and that the extractions
by Cu(OAc)2 and/or EUF-5 minutes serve as a useful basis for extimating zinc availability in rice soils. 相似文献
9.
The effects of nutritional copper deficiency on carrageenin edema in the rat were investigated with emphasis on studying the
correlation between the degree of copper deficiency and the degree of edema. Carrageenin paw edema in both copper-sufficient
and copper-deficient groups of rats was compared after either 20, 40, or 60 d on respective diets. The degree of copper deficiency
was quantitated by analyzing total copper concentrations in a number of tissues. Other copper dependent parameters were also
determined. Results indicated that: (1) although copper sufficient rats showed relatively little change in the degree of edema,
copper-deficient rats showed a steady and significant increase in edema from d 20 to 40 to 60; (2) paw edema in copper-deficient
animals was highly and negatively correlated to the concentrations of copper in the liver; the correlation with liver Cu,Zn-superoxide
dismutase activity, however, was inconsistent; (3) paw edema was not correlated either to copper concentration in tissues
other than liver or to plasma ceruloplasmin activity; and (4) aggravation of carrageenin edema in copper-deficient animals
seemed to be mediated via an as yet unknown secondary effect of copper deficiency. 相似文献
10.
The effect of tin and lead on levels of essential metals (Zn, Cu, Ca, Fe) in rabbit tissues was compared in relation to the route of administration. Animals received intraperitoneally, or per os, SnCl2 (2 mg Sn/kg) or Pb(CH3COO)2 (3.5 mg Pb/kg) every day for 5 d or for 1 mo. Copper, zinc, iron, and calcium were determined by AAS in the liver, kidneys, spleen, brain, bone marrow, and blood; lead and tin concentration were measured in the blood of animals. Tin and lead administered per os caused either no changes or the decreased concentration of endogenous metals in several tissues. The other route of administration (ip) of both metals generally contributed to the increased storage of essential elements. Blood tin levels of tin treated animals were only about less than or equal to 1/10 of blood lead concentrations of rabbits exposed to lead. 相似文献