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It has been found by gel-penetrating chromatography and quantitative 13C NMR spectroscopy that mechanochemical processing of arabinogalactan isolated from the wood of the Siberian larch changes the molecular mass distribution, monosaccharide composition, and the degree of branching of its macromolecules. This is due to the partial destruction of polysaccharide macromolecules and subsequent recombination of resulting fragments. The intensity of these processes depends on the conditions of mechanochemical processing. Based on the data of IR and 13C NMR spectra, the conclusion has been drawn that no functionalization of arabinogalactan macromolecules occurs under these conditions. The toxicopharmacological properties of mechanically processed arabinogalactan have been studied. Its acute toxicity is >5000 mg/kg.  相似文献   
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The effect of the chromosomal ends of Tetrahymena thermophila on the stability of linear transforming molecules in the filamentous fungus Podospora anserina was tested. A derivative of an integrative vector for this fungus has been constructed, so that after linearization, the ends of the plasmid are the telomeric sequences of T. thermophila. After transformation, this linear molecule was maintained as an extrachromosomal plasmid with no integrated copies in about 50% of the transformants. Under selective conditions, there was approximately one linear molecule per 5 to 10 nuclei, and these extrachromosomal molecules were rapidly lost under nonselective conditions. The circular plasmid carrying an inverted repeat of T. thermophila telomeres could be linearized and processed in vivo.  相似文献   
125.
Experiments were made on rabbit fed an atherogenic diet (0.5 g/kg cholesterol) singly for 15 and 24 h and repeatedly for 3, 9 and 30 days. At early stages of lipid metabolism distress the interrelationship was established between blood rheological disorders and microcirculatory abnormalities. The dependence of the initial reaction of some rheological characteristics on their initial level was marked.  相似文献   
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Electron microscopy of the adrenal medulla and cortex during the intermediate period of endotoxin shock has revealed severe destructive changes in parenchymal cells. These changes are the reason for synthetic, secretory and trophic disturbances of glandular functions. Ultrastructural lesions indicate that stress exposure exceeds the adaptive capacity of cells, the majority of which are exhausted and killed.  相似文献   
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OBJECTIVE--To test the hypothesis that farmers are at high risk of hip osteoarthritis and to investigate possible causes for such a hazard. DESIGN--Cross sectional survey. SETTING--Five rural general practices. SUBJECTS--167 male farmers aged 60-76 and 83 controls from mainly sedentary jobs. All those without previous hip replacement underwent radiography of the hip. MAIN OUTCOME MEASURES--Hip replacement for osteoarthritis or radiological evidence of hip osteoarthritis. RESULTS--Prevalence of hip osteoarthritis was higher in farmers than controls and especially in those who had farmed for over 10 years (odds ratio 9.3, 95% confidence interval 1.9 to 44.5). The excess could not be attributed to any one type of farming, and heavy lifting seems the likely explanation. CONCLUSIONS--Manual handling in agriculture should be limited where possible. Consideration should be given to making hip osteoarthritis a prescribed industrial disease in farmers. There may be wider implications for the prevention of hip osteoarthritis in the general population.  相似文献   
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Synthesis of prenylquinones in chloroplasts   总被引:3,自引:0,他引:3  
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