HPLC测定通痹胶囊中马钱子的士的宁含量

[目的]采用高效液相法测定通痹胶囊中士的宁的含量。[方法]C18色谱柱;以乙腈-0.01mol/L庚烷磺酸钠与0.02mol/L磷酸二氢钾等量混合溶液(用10%磷酸调节pH 2.8)(21∶79)为流动相。检测波长为260 nm,流速为1.0 mL/min,柱温为室温。[结果]士的宁在0.200~1.800μg时成良好线性关系,其平均回收率为98.96%,RSD为0.39%。10批样品平均士的宁含量为0.326 5 mg/粒。[结论]该方法简便、准确、重复性好,建立了测定通痹胶囊中马钱子的士的宁含量的可靠方法。     

Strychnine: its action on spinal motoneurons of cats

In cats strychnine does not alter measurably the potential, threshold, after potentials, or refractoriness of the membrane of the spinal motoneurons. Increased reflexes probably result from increase of excitatory impingement upon motoneurons. Spikes recorded during a rapid succession of nerve impulses produced by strychnine ("strychnine burst") suggest that soma membrane resistance is appreciable during stimulation.     

浅谈提高春制越年蚕种孵化率的对策

通过研究、分析和探讨,认为浴种后的保护温度不当、散卵浴消加速胚子活性化、不同蚕品种自身抵抗低温能力不同及蚕种保护阶段的温湿度和技术处理不当是影响春制越年蚕种孵化率的主要因素,加强蚕种的保护工作、适当推迟浴种时间、加强浴种后的蚕种冷藏保护工作、严格技术操作,减轻蚕卵摩擦、加强蚕种的出库技术处理等措施可以提高春制越年蚕卵的孵化率。     

Discrimination learning as the summation of excitation and inhibition

Pigeons received either excitatory, inhibitory, or combined excitatory and inhibitory (intradimensional) training to discriminate line-tilt stimuli. Algebraic summation of relative-generalization gradients obtained after separate excitatory and inhibitory training sessions was used to predict characteristics of gradients after intradimensional training. The good agreement between obtained and predicted gradients provided support for gradient-interaction theory.     

Identified sources and targets of slow inhibition in the neocortex

There are two types of inhibitory postsynaptic potentials in the cerebral cortex. Fast inhibition is mediated by ionotropic gamma-aminobutyric acid type A (GABA(A)) receptors, and slow inhibition is due to metabotropic GABA(B) receptors. Several neuron classes elicit inhibitory postsynaptic potentials through GABA(A) receptors, but possible distinct sources of slow inhibition remain unknown. We identified a class of GABAergic interneurons, the neurogliaform cells, that, in contrast to other GABA-releasing cells, elicited combined GABA(A) and GABA(B) receptor-mediated responses with single action potentials and that predominantly targeted the dendritic spines of pyramidal neurons. Slow inhibition evoked by a distinct interneuron in spatially restricted postsynaptic compartments could locally and selectively modulate cortical excitability.     

Hemichannel-mediated inhibition in the outer retina

An essential feature of the first synapse in the retina is a negative feedback pathway from horizontal cells to cones. Here we show that at this synapse, connexin26 forms hemichannels on horizontal cell dendrites near the glutamate release site of the cones. Blocking these hemichannels hyperpolarizes horizontal cells, modulates the Ca2+ channels of the cones, and abolishes all feedback-mediated responses. We propose a feedback mechanism in which the activity of the Ca2+ channels and the subsequent glutamate release of the cones are modulated by a current through these hemichannels. Because the current through the hemichannels depends on the polarization of the horizontal cells, their activity modulates the output of the cones.     

抑制杨木APMP纸浆返黄技术的研究(Ⅲ)——助剂用量及抑制杨木APMP纸浆返黄机理的研究

优选助剂组合ZW-1/抗坏血酸/次亚磷酸钠处理黑杨APMP纸浆取得了令人满意的光稳定效果.用紫外光辐照、干/湿热老化处理,作者对组合中各助剂优化用量以及助剂组合处理改善黑杨APMP纸浆光稳定性能的机理进行了研究.结果表明,组合中各助剂优化用量分别为0.25%,0.5%,1.0%;助剂组合处理能够有效改善黑杨APMP纸浆光稳定性能,是因为减少了模拟光老化过程中芳核羧基的含量.     

前茬作物对富源县植烟土壤养分的影响

对富源县低、中、高海拔烟区植烟土壤养分测定表明,各海拔段烟区植烟土壤全钾和全磷含量较低,均处于中等偏下水平。在各海拔段植烟土壤种植不同前茬作物,并测定前茬作物对植烟土壤综合肥力的影响。结果表明,低海拔(1 700m)烟区前茬为豌豆时,土壤肥力最高,但应补充氮素;中海拔(1 700-2 000 m)烟区前茬为空闲时,土壤肥力最高,但应控制水溶性氯含量;高海拔(2 000 m)烟区前茬为油菜时,土壤肥力最高,但应控制土壤中有效硫和水溶性氯的含量。     

Glycine inhibition of asparaginase

Administration of either Escherichia coli asparaginase or guinea pig serum to C3H/HE mice with the 6C3HED lymphosarcoma is followed by depression of glycine in the tumor. This decrease in cellular glycine concentration does not occur in a tumor resistant to asparaginase. The inhibition of the lymphosarcoma by asparaginase can be reversed by intraperitoneal injection of asparagine or glycine. This reversal appears to be specific because lysine, threonine, serine, and aspartic acid were ineffective. Loss of cellular glycine may be more important than loss of asparagine because of the requirement for glycine in purine synthesis.     

Small-molecule inhibition of TNF-alpha

We have identified a small-molecule inhibitor of tumor necrosis factor alpha (TNF-alpha) that promotes subunit disassembly of this trimeric cytokine family member. The compound inhibits TNF-alpha activity in biochemical and cell-based assays with median inhibitory concentrations of 22 and 4.6 micromolar, respectively. Formation of an intermediate complex between the compound and the intact trimer results in a 600-fold accelerated subunit dissociation rate that leads to trimer dissociation. A structure solved by x-ray crystallography reveals that a single compound molecule displaces a subunit of the trimer to form a complex with a dimer of TNF-alpha subunits.     

半喂入式花生摘果机的设计与性能测试

为满足花生分段收获机械化生产的需要,在对中国现有花生摘果装置系统分析的基础上,设计一种半喂入式花生摘果机。该机传动系统采用柴油机为动力源,具有2条传动系统分支,分别为夹持输送装置传动系统和摘果装置传动系统;摘果装置为叶片式双辊筒差相组配结构形式,倾斜配置安装;夹持输送装置采用单夹持链与输送导轨相夹紧的结构。通过摘果性能试验,测试摘果滚筒转速大小、夹持输送速度对花生荚果摘净率、破损率的影响。测试结果表明:摘果滚筒转速对摘净率及破碎率影响均极为显著,夹持输送速度对摘净率的影响为极显著,而对破损率影响不显著,设计的摘果机在作业条件下,各项性能指标均能较好地满足半喂入式摘果机具的质量要求。     

中华医学会历届医学信息学术会议获奖论文分析

统计分析了中华医学会历届医学信息学术会议获奖论文的作者、作者单位、研究主题等指标,讨论了获奖论文的研究与创新特色,研究结果对揭示我国医学信息领域的学术研究状况、提高我国医学信息领域的学术研究水平有借鉴意义。     

6-BA等对番茄种子发芽与幼苗生长的影响

本文分析赤霉素(GA3)、吲哚乙酸(IAA)及6-苄氨基嘌呤(6-BA)等植物生长调节剂对番茄种子发芽与幼苗生长的影响.结果表明:不同植物生长调节剂对番茄种子发芽和幼苗生长的影响不同,同一植物生长调节剂的不同浓度也有不同的影响.与CK对比,GA3促进番茄种子发芽与幼苗生长的最佳浓度为100mg/L;而IAA与6-BA的理想浓度则分别为100mg/L和10mg/L.其中,10mg/L的6-BA对番茄种子发芽和幼苗生长的作用效果最好.     

Phytohemagglutinin: inhibition of the agglutinating activity by N-acetyl-D-galactosamine

The effect of simple sugars on the agglutinating activity of phytohemagglutinin was studied. N-Acetyl-d-galactosamine selectively inhibits the agglutination of leukocytes and erythro- cytes by phytohemagglutinin.