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291.
In this article, an attempt has been made to explain the failure mechanism of spun yarns. The mechanism includes the aspects of generation and distribution of forces on a fibre under the tensile loading of a yarn, the free body diagram of forces, the conditions for gripping and slipping of a fibre, and the initiation, propagation, and ultimate yarn rupture in its weakest link. A simple mathematical model for the tenacity of spun yarns has been proposed. The model is based on the translation of fibre bundle tenacity into the yarn tenacity.  相似文献   
292.
ABSTRACT:   Ecological investigations were carried out on Indian marine puffers, Chelonodon patoca, Sphaeroides oblongus, Lagocephalus lunaris and Lagocephalus inermis , the four major species available in the coastal waters of the Bay of Bengal, India. The seasonal intraspecific and interspecific abundance and average daily landings were noted. The high hepatosomatic index and low lipid ratio of muscle to liver indicated accumulation of lipid in the liver. The lipid content was at its maximum during the monsoon (July–October) in all the species as was observed from the study of the seasonal variation of liver lipids. The puffers are mainly bottom feeders and the molluscs Umbonium vesterium and Donax incarnatus are the major prey group, constituting 56.0–87.5% of their food content. The liver and ovary had the maximum toxicity in monsoon during their spawning season. The liver oils so far tested from these fishes had no toxicity and the study reveals that the ecologic information will be helpful in monitoring the quality for the safe isolation of polyunsaturated fatty acid – enriched oil from these non-conventional sources.  相似文献   
293.
The mulberry leaves have been considered as a sole food source for silkworm, Bombyx mori (L.). In present work an attempt was made to investigate the role of low molecular weight peptide(s) isolated from mulberry leaves on silkworm rearing. Also we have tried to find out the role of free-radical scavenging activities of isolated peptide(s) on silkworm growth. Larval growth rate was found effective under the influence of peptide(s). Consumption rate of larvae after peptide(s) treatment on mulberry leaves was significantly enhanced over control. High antioxidant activity was found in Low molecular weight peptide(s) which have an effect on silkworm.  相似文献   
294.
Field trials with six times normal nitrogen supply produced a significant increase in the proportion of female papaya plants. The addition of nitrogen to the soil increased the leaf nitrogen content but had no effect on the amino acid content. Leaves of male plants contained more nitrogen than female plants but no difference could be detected in the contents of amino acids in the leaves and flower buds. Foliar application of 1-naphthalene acetic acid (NAA) and 2-chloroethyl-trimethyl ammonium chloride (CCC) resulted in a higher female : male ratio, but maleic hydrazide (MH) and gibberellic acid (GA3) enhanced maleness. The animal sex hormone stilboesterol dipropionate had no apparent effect on sex expression but the application of testosterone propionate increased the proportion of male plants.  相似文献   
295.
European Journal of Plant Pathology - Populus davidiana × Populus bolleana (PdPap) root rot caused by Fusarium oxysporum is a major disease in China. Controlling this disease...  相似文献   
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Soluble and hydrophobic lipid breakdown products have a variety of important signaling roles in cells. Here sphingoid bases derived in cells from sphingolipid breakdown are shown to have a potent and direct effect in mediating calcium release from intracellular stores. Sphingosine must be enzymically converted within the cell to a product believed to be sphingosine-1-phosphate, which thereafter effects calcium release from a pool including the inositol 1,4,5-trisphosphate-sensitive calcium pool. The sensitivity, molecular specificity, and reversibility of the effect on calcium movements closely parallel sphingoid base-mediated inhibition of protein kinase C. Generation of sphingoid bases in cells may activate a dual signaling pathway involving regulation of calcium and protein kinase C, comparable perhaps to the phosphatidylinositol and calcium signaling pathway.  相似文献   
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