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121.
拉萨郊区藏族的指纹研究 总被引:2,自引:0,他引:2
本文报道了拉萨郊区517例(男226人,女291人)藏族健康人的指纹参数正常值、调查分析了指纹类型、指纹组合、指纹指数和指嵴纹计数。比较了藏族不同居群、不同民族和人种间的差异。结果表明,藏族有自己的指纹特点,又显著蒙古人种的一般特征。 相似文献
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本实验用fura-2 荧光技术研究离体鼠心缺氧期间心肌细胞内游离钙浓度(Ca^2+)增加的机制。实验结果为:(1)Krebs-Henseleit(K-H)液缺氧灌流离体鼠心脏引起(Ca^2+)先慢后快地增国(2)无钙液氧灌流,仍能引起(Ca蓿玻黾印#ǎ常┖ǎǎ保薄粒保埃蓿担恚铮欤蹋┑模耍纫喝毖豕嗔鳎ǎ茫幔蓿玻┑谋浠嗨莆薷埔喝毖豕嗔鳎伊秸咭鸬模ǎ茫幔蓿玻┰黾樱飨缘陀? 相似文献
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Dispersed acini from rat pancreas were used to examine the effects of various pancreatic secretagogues on the fine structure of the acinar cell plasma membrane. With the C-terminal octapeptide of cholecystokinin, the C-terminal tetrapeptide of cholecystokinin, carbamylcholine, bombesin, A23187, vasoactive intestinal peptide or 8-bromo cyclic adenosine monophosphate, concentrations of the secretagogues that caused maximal stimulation of enzyme secretion did not produce alterations of the acinar cell plasma membrane. Supramaximal concentrations of the C-terminal octapeptide of cholecystokinin, the C-terminal tetrapeptide of cholecystokinin or carbamylcholine induced the formation of cytoplasmic protrusions at the basolateral plasma membrane of the pancreatic acinar cell, whereas supramaximal concentration of bombesin, A23187, vasoactive intestinal peptide or 8-bromo cyclic AMP did not alter the morphology of the acinar cell. Effects of the C-terminal octapeptide of cholecystokinin could be detected as early as after two minutes of incubation and these effects progressed for up to 30 minutes of incubation. 相似文献
126.
Thylakoid membranes of the cyanobacterium Plectonema boryanum solubilized with Triton X-100 can be resolved into three fractions of pigment-protein complexes (Hladík, J. and Sofrová, D. (1981) Photosynthetica 15, 490–503). Fraction I contained relatively the highest amount of carotenoids as well as monomeric forms of chlorophyll a, Fractions II and III contained chlorophyll-protein complexes with a characteristic exciton-split circular dichroism in the red region. It has been shown that fraction III is an oligomeric form of the chlorophyll-protein complex of fraction II. Circular dichroism spectra indicate that, different from fraction II, fraction III contains specifically oriented and space-fixed molecules of carotenoids. Thermal dissociation of fracion III to fraction II is accompanied by disappearance of the positive circular dichroism effect of carotenoids in the 500–550 nm region, thus causing deorganization of the carotenoids, proceeding in parallel to the geometrical rearrangement of chlorophyll molecules. Extraction of the carotenoids of fraction III with heptane is acompanied by dissociation of fraction III. We assume that the observed effects are due to binding of the two pigments to the protein component of the complex and that carotenoids can mediate a part of the interactions which stabilize the structure of pigment-protein complexes. Thus, besides the light-harvesting and protective functions, carotenoids can also play a structural role. 相似文献
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水生植物叶片的功能性状特征与陆生植物有所不同,同时叶脉类型也显著影响叶片的功能性状。本研究选取9种具有不同叶脉类型的水生植物,通过对叶脉进行直接损伤,分析叶片性状(形态、色素含量和叶绿素荧光指标)在叶脉受损后的变化程度与叶脉类型的关系。结果显示:具有平行脉的3种水生植物对叶脉损伤具有较强的耐受性;具羽状脉的4种植物主脉受损后显著抑制叶片生长,而侧脉受损的影响在不同物种间有所不同,具有物种特异性。本研究可为大型湖泊水生植物修复的水生物种筛选提供参考。 相似文献
128.
Action of cholera toxin on dispersed acini from rat pancreas. Post-receptor modulation involving cyclic AMP and calcium 总被引:1,自引:0,他引:1
In dispersed acini from rat pancreas, cholera toxin caused a significant increase in cellular cyclic AMP but little or no change in amylase secretion. The presence of a secretagogue that causes mobilization of cellular calcium (e.g., cholecystokinin, carbamylcholine, bombesin or ionophore A23187) caused a substantial increase in the effect of cholera toxin on enzyme secretion. Cholera toxin did not alter calcium transport or the changes in calcium transport caused by other secretagogues, and secretagogues that mobilize cellular calcium did not alter cellular cyclic AMP or the increase in cyclic AMP caused by cholera toxin. These results indicate that in dispersed acini from rat pancreas there is post-receptor modulation of the action of cholera toxin by secretagogues that mobilize cellular calcium and that this modulation is a major determinant of the effect of the toxin on enzyme secretion. 相似文献
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