蓬辣滩水电站泄洪闸门及其监控系统改造

介绍了蓬辣滩水电站泄洪闸门的状况、计算机监控系统改造方案的结构和特点及闸门定轮轴承的改造情况,通过上述改造,提高了泄洪设备运行的自动化水平,同时也为其他闸门工程提供参考。     

WHERE ARE THE GATES IN GAP JUNCTION CHANNELS?

1. In the formation and function of gap junction channels two types of gates ought to be discriminated: the docking gate and the channel gates proper. The docking gate is involved in the transformation of a closed hemichannel to a patent gap junction channel. By definition the trigger mechanism for this gate and maybe even the gate itself is contained within the extracellular loops of the gap junction proteins, the connexins. The channel gates proper determine the open and closed states of the complete gap junction channels. 2. Probing the docking gate by mutagenesis of connexins and by synthetic peptides indicates that this gate is the consequence of complex interactions between a large fraction of the amino acids comprising the extracellular loops. Probably both inter- and intra-molecular interactions are involved, and disulfide exchange may be entailed in the stabilization of the open and closed states. 3. Of the various effectors on the channel gate(s) the voltage effects have obtained the most scrutiny to date. The response of gap junction channels and hemichannels is diverse, the various channels respond differently to transjunctional and membrane potential. No equivalent to the S4 segment representing the voltage sensor in other voltage dependent ion channels is present in the connexin sequences, instead mutations in various segments of connexins have been reported to affect the voltage dependence of gap junction channels. To understand the complexity of voltage effects on gap junction channels, non-connexin peptides may need to be considered as voltage sensors or as modifiers thereof.     

Conductance properties and voltage dependence of an anion channel in amphibian skeletal muscle

Single anion-selective channels were studied in excised membrane patches of adult frog toe muscle. The conductance and the probabilityp _o of the main open state were determined for various ionic compositions of the extra-and intracellular solutions. =280 pS in symmetrical 110 mM NaCl, pH 7.4 solutions at 15°C. Higher values were found at elevated internal or external NaCl concentrations, in 70 mM external CaCl₂ and at lower extracellular pH. Thep _o(E) curve declined steeply with hyperpolarization and was shifted towards more negative potentials at increased internal ionic strength and at higher external pH. Positive shifts were induced by extracellular Ca. The results show that the anion channel saturates at Cl concentrations >110 mM, that the potential profile of an open channel is almost symmetrical and that channel gating is affected by neighboring channels. It is suggested that the anion channel has a voltage sensor (effective gating charge 4.3) and a similar collection of local fixed charges on the extra- and intracellular sides as voltage-gated cation channels.     

高原不同海拔地区儿童肺活量肺通气量与形态指标的相关性

目的了解高原不同海拔地区儿童肺活量肺通气量与形态指标的相关性,以便为制定高原性疾病防控策略提供参考依据。方法于2019年1月至2020年6月采用随机抽样调查法,选择青海西宁地区(海拔2260 m,低海拔组)、青海海西地区(海拔2900 m,中海拔组)、青海玉树地区(海拔4493 m,高海拔组)7~15岁中小学生作为研究对象,检测受试儿童肺活量、肺通气量和形态指标。结果低海拔组、中海拔组、高海拔组肺活量、肺通气量和形态指标比较,差异均有统计学意义(P均<0.05)。肺活量、肺通气量与肺容积呈正比关系,与肺密度、肺径线呈反比关系(P<0.05)。研究数据的logistic回归分析显示,影响儿童肺活量和肺通气量的因素有以下3个:肺密度平均值、全肺横径、全肺容积,且以上因素差异间有统计学意义(P<0.05)。结论监测儿童形态指标,关注肺密度平均值、全肺横径、全肺容积可有效判断儿童肺功能,对防治相关高原性疾病的发生具有一定价值。     

Macromorphology and histology of intramuscular hemorrhages in cases of drowning

In a prospective autopsy series of 39 cases of fatal drowning, the detailed dissection of the skeletal muscles of the neck, anterior / posterior trunk and the upper extremities in layers revealed intramuscular hemorrhages of different size and shape in 20 cases (51.3 %). Light microscopy examination showed a premortal (vital/agonal) type of muscular alteration in 7 (50 %) out of 14 macroscopical hemorrhage-positive cases. These hemorrhages and histological muscle alterations are attributed to agonal convulsions, hypercontraction and overexertion of the affected muscle groups. As long as no cutaneous or subcutaneous hematomas above the hemorrhages can be found, these autopsy findings (with special reference to histology) can serve as an additional criterion concerning the differentiation of drowning and another cause of death. Received: 31 July 1998 / Received in revised form: 31 August 1998     

Time-dependent RNA synthesis in different skin layers after wounding. Experimental investigations in vital and postmortem biopsies

Summary Incision wounds were made on the outer ear of rats and two biopsies were taken for examination after different survival times. In each case a biopsy was made of vital tissue and a second of postmortem tissue after refrigeration for 24 h. The biopsies were exposed to a solution containing the RNA precursor³H-cytidine for 1 h, washed and fixed in formalin. Sections 5 m thick were then autoradiographically prepared and automatically evaluated using Quantimet 920. The intravital specimens showed a significant increase in³H-cytidine incorporation in the basal cell layer after survival times of 10–24 h. No increase was seen in the stratum corneum, corium or cartilage tissue. The investigated distance from the wound margin did not have any significant bearing on the results. The³H-cytidine incorporation rate in postmortem tissue was practically identical with that of vital tissue, but no increase was observed in the rate of RNA synthesis in the basal cells as a function of the age of the wound. It may therefore be assumed that this method provides no additional information as to the age of wounds in postmortem examination.Dedicated to Professor O. Pribilla on the occasion of his 70th birthday     

下咽癌淋巴引流的活体显像研究

目的：探讨下咽癌颈淋巴结转移时肿瘤区域引流淋巴结的活体显像方法，从肿瘤活体淋巴引流的角度观察下咽癌前哨淋巴结和颈淋巴结转移的方式，为颈淋巴结清扫术提供指导信息。方法：在表面麻醉和喉内镜引导下，用特制的注射针将^99mTc标记的人球蛋白注入20例下咽癌的肿瘤部位，在注射后不同时间采用SPECT扫描观察放射性核素通过淋巴扩散的过程及其在引流淋巴结内的浓集，以明确前哨淋巴结的位置和肿瘤颈淋巴结引流过程。同时对颈淋巴清扫标本进行病理检查。结果：20例肿瘤引流淋巴结均获得满意活体显像，显像的淋巴结最大3．5cm，最小1．0cm；12例梨状窝癌的颈部引流淋巴结位于肿瘤侧，其余8例中线结构的肿瘤颈部引流淋巴结均具有明显的优势偏向，即单侧颈部引流现象，没有出现双侧对称引流的病例。20例肿瘤引流淋巴结主要分布在Ⅱ、Ⅲ、Ⅳ区，未发现Ⅰ区和Ⅴ区显像的淋巴结。术后病理证实20例中有16例发现病理阳性淋巴结，且均位于引流优势侧，未出现对侧和双侧颈淋巴结转移的病例。结论：无论是中线结构或偏中线结构的下咽部癌肿，其向颈部的淋巴引流具有明显的优势偏向特点，术前进行引流淋巴结的活体显像对预测肿瘤转移部位和有目的地进行择区性颈淋巴结清扫术具有重要意义。     

湖南省学生1995年和2000年肺活量抽样调查分析

目的了解湖南省学生呼吸功能发育状况,探讨其变化趋势.方法于1995年和2000年在湖南省的长沙市、常德市、衡阳市和湘西自治州采用整群分层抽样和统一调查、检测方法,对学生体质健康状况调查,采用U检验对调查资料按年度、年龄、性别和城乡比较分析.结果从肺活量(ml)和肺活量指数(ml/kg)进行统计分析的结果显示,总体水平低于全国平均水平,1995年未达到全国平均水平的城乡男女年龄组有36个,2000年则增至38个;2000年与1995年进行肺活量指数比较,城乡男女共有33个年龄组下降;另外还呈现出城市高于农村,男生大于女生的特点.结论湖南省学生肺活量在全国处较低水平,且城乡男女多数年龄组呈现下降趋势,并有较明显的城乡差异和性别差异.     

湖北省初中生身体形态机能发育动态分析

目的分析湖北省初中生形态机能指标检测结果,为研究初中生生长发育规律,改善学生体质健康状况提供依据.方法采用文献资料法、比较法和数理统计法,分析研究1991～2000年全国学生体质健康调查湖北片区资料.结果学生形态发育水平明显提高,肺功能下降.乡村男生身高平均增长0.37 cm;城、乡男生和城市女生体重分别平均增加0.64 kg,0.36kg和1.28 kg.城乡男生胸围分别平均增加1.62 cm和2.49 cm;城乡男生和女生肺活量分别平均下降172.67 mL,338.82 mL,130.51 mL和359.24 mL.结论湖北省初中生形态发育水平明显提高,城乡差异缩小,肺功能持续下降.10 a间初中生形态和肺功能发育水平不同步;学生营养状况得到改善,但体育锻炼不足.     

机动门脉动真空灭菌器的常见故障及改进

本文介绍了一种最新型灭菌消毒柜的工作原理,工作条件,常见故障的维修及其改进措施。