脑电图机电极与头皮接触阻抗的检测

脑电图机中电极与头皮接触的好坏对脑电波形质量有很大影响，本文利用AT89C51单片机实现电极与头皮接触阻抗的检测。还通过发光二极管给予医务人员对电极接触好坏直观的指示。     

The cytokinin-like effect of a lowered temperature on the micromorphology ofNicotiana tabacum L.

The lowering of the cultivation temperature allows one to alter the growth intensity and micromorphology of tobacco cell strains specifically. By a long-term low temperature treatment the effect is deepened, by transferring inocula into normal cultivation temperature it is repaired. Both the growth and morphogenic effects of the low temperature correspond to those of cytokinins, exhibiting even the same strain specificity.     

Biosynthesis of Callose and Cellulose by Detergent Extracts of Tobacco Cell Membranes and Quantification of the Polymers Synthesized in vitro

The conditions that favor the in vitro synthesis of cellulose from tobacco BY-2 cell extracts were determined. The procedure leading to the highest yield of cellulose consisted of incubating digitonin extracts of membranes from 11-day-old tobacco BY-2 cells in the presence of 1 mM UDP-glucose, 8 mM Ca2+ and 8 mM Mg2+. Under these conditions, up to nearly 40% of the polysaccharides synthesized in vitro corresponded to cellulose, the other polymer synthesized being callose. Transmission electron microscopy an...     

实体肿瘤内毛细血管—跨毛细血管壁—组织间质流体耦合流动的解析解

在微观尺度上建立实体肿瘤组织内单根毛细血管—跨毛细血管壁—组织间质内流体的不定常耦合流动模型，求解析解。模型中假设毛细血管为一可渗透刚性圆柱管，周围组织为各向同性多孔弹性介质。毛细血管内流动遵循Navier—Stokes方程，跨血管壁和间质内组织液流动采用Starling定律和Davy定律。所得解析解结果显示①微观尺度上可忽略毛细血管内液体渗出量，管内流动可视为Poiseuille流动；②肿瘤组织间质压分布平坦，组织液流动缓慢，物质对流扩散困难。同时不定常解析解的取得也为今后肿瘤药物施药方案的进一步研究提供了数学上的准备。     

RLINl,encoding a putative coproporphyrinogen Ⅲ oxidase,is involved in lesion initiation in rice

Lesion mimic is necrotic lesions on plant leaf or stem in the absence of pathogenic infection,and its exact biological mechanism is varied.By a large-scale screening of our T-DNA mutant population,we identified a mutant rice lesion initiation 1(rlin1),which was controlled by a single nuclear recessive gene.Map-based cloning revealed that RLIN1 encoded a putative coproporphyrinogen Ⅲ oxidase in tetrapyrrole biosynthesis pathway.Sequencing results showed that a G to T substitution occurred in the second ex...     

膀胱功能代偿系统的研究

本文对截瘫病人膀胱功能障碍的重建机理和方法进行了综合分析,对临床上解决膀胱功能代偿的各种途径加以比较,提出膀胱功能代偿系统-膀胱控制器的新设计,它将会使我国广大的膀胱功能障碍患者受益。     

Stimulation of multiple shoot regeneration from seedling leaves of Hypericum perforatum L. by pluronic F-68

The effects of the non-ionic surfactant, Pluronic F-68, on the growth of shoots regenerated from seedlings (14 days post-germination) of Hypericum perforatum L. were studied. The supplementation of agar-solidified medium with 0.001% (w/v) of Pluronic increased the mean fresh weight of the regenerants after 60 days by 40% and the mean number of plant regenerants recovered per seedling by 34%; a less pronounced increase in the number of regenerants occurred with 0.01% (w/v) of the surfactant. By contrast, the mean fresh weight of the regenerants cultured in the presence of 0.1% (w/v) Pluronic F-68 was 15% lower than untreated controls, although the mean number of regenerants per seedling remained unaltered. The growth of seedling leaf-derived Hypericum callus after 60 days was unaffected by all the concentrations of Pluronic tested. However, there was a tendency for callus cells grown in the presence of Pluronic to be more highly pigmented with anthocyanins. The cultivation of leaf explants with 0.001% or 0.01% (w/v) Pluronic did not affect either the mean fresh weight of the regenerants or the mean number of regenerants per explant. However, decreases in both the mean fresh weight and the mean number of regenerants (both 33.0% lower than the control) occurred following the cultivation with 0.1% (w/v) Pluronic.     

Transgenic mice overexpressingγ-aminobutyric acid transporter subtypeⅠ develop obesity

INTRODUCTION7-aminobutyricacid(GABA)isthemajorinhibitoryneurotransmitterinthevertebratecelltralnervoussystemwhereitactingesavaxietyofGABAreceptortypes.TheneurotransmissionofGABAisthoughttobeterllilnatedbyit'srapidre-uptakeviaGABAtransportersintopresynapticneuronsandsurroundingglialcellsll,2].BesidesfUnctioningintheterminationofsynaptictransmission,GABAtransportersplayacriticalroleintheregUlationofthemagnitudeanddurationofGABA'sactionandmayajsomediatethereleaseofGABAintotheedrac…     

Mass transfer in fermentation

An essential consideration in the design and operation of commercial fermenters is to ensure adequate mass transfer. The complex composition of fermentation liquids makes it difficult to predict accurately the mass transfer characteristics in large vessels. Here various aspects of mass transfer are discussed and their relationships examined. Strategies for predicting the most important type of mass transfer — between gases and liquids — in large scale fermentations are presented.