998 resultados para 35-325
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Effects of La3+ and Gd3+ on Ca2+ influx were investigated in rat hepatoma H-35 cells by measuring the initial rate of Ca-45(2+) uptake. It was found that the maximum initial rate of Ca2+ uptake was increased six- to ten-fold at low concentrations of La3+ and Gd3+. Kinetic analyses by measuring the initial rate of Ca2+ influx at different external Ca2+ concentrations indicated the existence of two intracellular exchangeable components in the basal Ca2+ system, with low and high affinities for Ca2+, and only one class of Ca2+ binding sites was observed in the La3+- or Gd3+-treated cells. For high affinity, La3+ and Gc(3+) increased both kinetic parameters K-m and V-max of basal Ca2+ influx. La3+ and Gd3+ compete directly with Ca2+ for Ca2+ binding site for low affinity. The kinetics is competitive.
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通过测定 4 5Ca2 +摄取初速度的变化研究了La3+和Gd3+对鼠肝癌H 3 5细胞Ca2 +内流的影响 .发现低浓度La3+和Gd3+能增加肝癌H 3 5细胞Ca2 +内流初速度达 6~ 10倍 .Ca2 +内流的初速度随Ca2 +浓度变化的动力学研究表明 ,肝癌H 3 5细胞中存在 2类Ca2 +亲和部位的通道 ,即高亲和位和低亲和位Ca2 +内流通道 ,而La3+和Gd3+刺激的肝癌H 3 5细胞则只有 1类Ca2 +亲和位通道 ,La3+和Gd3+增加高亲和位Ca2 +结合通道的Km和Vmax,而对于低亲和位的Ca2 +结合通道Ca2 +内流的作用是竞争性的.
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The concentrations of five major and 28 trace elements in 35 marine algae collected along the coast of China were determined by instrumental neutron activation analysis. The concentrations of halogens, rare earth elements and many transition metal elements in marine algae are remarkably higher than those in terrestrial plants. The concentration factors for 31 elements in all collected algae were calculated, those for tri- and tetra-valent elements were higher than those of the mono- and di-valent elements in marine algae. The biogeochemical characteristics of inorganic elements in marine algae were investigated. In addition, the seasonal variation of inorganic elements in Sargassum kjellmanianum was also studied. (C) 1998 Elsevier Science B.V. All rights reserved.
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我们在野外条件下利用赤狐的粪尿增加高原鼠兔的捕食风险,采用目标动物抽样法对高原鼠兔的5种行为进行观察,分析天敌动物气味增加与天敌动物数量增加对高原鼠兔行为影响的差异,探讨高原鼠兔对捕食风险的权衡能力及面对不同风险的行为决策。2001年,在捕食风险处理样方中观察雄性成体18只,雌性成体25只,雄性幼体35只和雌性幼体42只,在对照样方中观察雄性成体14只,雌性成体15只,雄性幼体22只和雌性幼体11只;2002年,在捕食风险处理样方中观察雄性成体7只,雌性成体12只,在对照样方中观察雄性成体8只,雌性成体15只。研究结果表明:增加赤狐的气味后,高原鼠兔通过改变行为策略以适应捕食风险的增加。当气味源刚放入后,与对照样方比较,高原鼠兔明显增加了观察和呜叫的频次,相应减少了取食的频次,且随着时间的推移,高原鼠兔并未对气味产生适应性。当天敌动物的数量增加后,赤狐气味的增加对高原鼠兔行为的影响较小,在捕食风险超出高原鼠兔的耐受范围时,高原鼠兔扩散。同时,高原鼠兔的行为在雌雄之间、成体与幼体之间没有明显的不同,雌雄个体、成幼体均采用相同的行为策略减小捕食风险。以上结果表明:捕食风险明显影响高原鼠兔的行为,高原鼠兔能够权衡捕食风险的大小,并依据风险水平的高低采用相应的行为策略,其行为调节符合捕食风险时间分配的假说。
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该书以陕西勉(县)-略(阳)-阳(平关)地区铜厂铜金多金属矿田为例,在总结构造成矿动力学的理论和方法基础上,从成矿地质背景、矿床地球化学、矿田地质力学、矿田构造地球化学及矿田构造应力场等方面对研究区进行了系统地构造成矿动力学研究,根据所获研究成果对该区进行了隐伏矿定位预测。全书约35万字,共分7章,其中图¨6幅、表53个、照片62张。陈庆宣院士为该书作了序。
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A series of MCM-22/ZSM-35 composites has been hydrothermally synthesized and characterized by XRD, SEM, particle size distribution analysis, N-2 adsorption and NH3-TPD techniques. Pulse and continuous flow reactions were carried out to evaluate the catalytic performances of these composites in aromatization of olefins, respectively. It was found that MCM-22/ZSM-35 composites could be rapidly crystallized at 174 degrees C with an optimal gel composition of SiO2/Al2O3=25, Na2O/SiO2=0.11, HMI/SiO2=0.35, and H2O/SiO2=45 (molar ratio), of which the weight ratio of ZSM-35 zeolite in the composite relied on the crystallization time. The coexistence of MCM-22 and ZSM-35 in the composite (MCM-22/ZSM-35=45/55 wt/wt) was observed to exert a notable synergistic effect on the aromatization ability for butene conversion and FCC gasoline updating, possibly due to the intergrowth of some MCM-22 and ZSM-35 layers.
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1999
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Practice Links is a free e-publication for practitioners working in Irish social services, voluntary and nongovernmental sectors. Practice Links was created to enable practitioners to keep up-to-date with new publications, electronic resources and conference opportunities. Issue 35 examines the work of Positive Behaviour Ireland and the new pre-school Curriculum framework; Aistear
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For word-cued autobiographical memories, older adults had an increase, or bump, from the ages 10 to 30. All age groups had fewer memories from childhood than from other years and a power-function retention for memories from the most recent 10 years. There were no consistent differences in reaction times and rating scale responses across decades. Concrete words cued older memories, but no property of the cues predicted which memories would come from the bump. The 5 most important memories given by 20- and 35-year-old participants were distributed similarly to their word-cued memories, but those given by 70-year-old participants came mostly from the single 20-to-30 decade. No theory fully accounts for the bump.
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In this review, we discuss recent work by the ENIGMA Consortium (http://enigma.ini.usc.edu) - a global alliance of over 500 scientists spread across 200 institutions in 35 countries collectively analyzing brain imaging, clinical, and genetic data. Initially formed to detect genetic influences on brain measures, ENIGMA has grown to over 30 working groups studying 12 major brain diseases by pooling and comparing brain data. In some of the largest neuroimaging studies to date - of schizophrenia and major depression - ENIGMA has found replicable disease effects on the brain that are consistent worldwide, as well as factors that modulate disease effects. In partnership with other consortia including ADNI, CHARGE, IMAGEN and others(1), ENIGMA's genomic screens - now numbering over 30,000 MRI scans - have revealed at least 8 genetic loci that affect brain volumes. Downstream of gene findings, ENIGMA has revealed how these individual variants - and genetic variants in general - may affect both the brain and risk for a range of diseases. The ENIGMA consortium is discovering factors that consistently affect brain structure and function that will serve as future predictors linking individual brain scans and genomic data. It is generating vast pools of normative data on brain measures - from tens of thousands of people - that may help detect deviations from normal development or aging in specific groups of subjects. We discuss challenges and opportunities in applying these predictors to individual subjects and new cohorts, as well as lessons we have learned in ENIGMA's efforts so far.