不同急性血液循环稀释对大鼠血压,心率和呼吸的影响

本实验采用生理盐水和右旋糖酐两组不同急性血液循环稀释度观察对大鼠血压、心率和呼吸的影响。实验结果表明,随着血液循环稀释度增加,两组平均动脉血压都明显降低(P<0.05和<0.01);心率变化生理盐水稀释组变化不大(P>0.05),右旋糖酐稀释组加快(P<0.01);呼吸频率变化生理盐水稀释组有变慢的现象但意义不大(P>0.05),右旋糖酐稀释组出现先快后慢再快的现象(P>0.05)。提示这两种液体稀释血液循环后对血压、心率和呼吸具有相同也有不同之处,最后对这两种液体稀释血液后对心血管功能影响进行了初步的分析。     

儿童化学发光免疫分析中稀释方法的探讨

目的:探讨儿童化学发光免疫分析中标本量过少时,用怎样的稀释介质以及稀释方法解决这个问题,分析不同的稀释介质产生的基质效应。方法:本实验以儿童常规筛查检测项目血清三碘甲状腺原氨酸(TT3)为例,选取血清样本30例,分别使用美国贝克曼库尔特公司UniCel DXI800 Access化学发光免疫分析仪测试药盒三碘甲状腺原氨酸(TT3)配套TT3定标液S0(简称TT3S0)、0.9%氯化钠、医用蒸馏水作为稀释介质进行手工2倍(1:1)及4倍(1:3)后测定。计算稀释测定结果与原始数据的差异,观察基质效应对检测结果的影响。寻找实际工作中可运用的稀释介质和稀释倍数。结果:不同稀释组与原始值之间比较,TT3S02倍(t=0.7937,P0.05)、4倍稀释(t=-0.2503,P0.05),以及蒸馏水2倍稀释(t=-0.2845,P0.05)差异均无统计学意义。而0.9%氯化钠2倍(t=-6.4686,P0.05)、4倍稀释(t=-3.9842,P0.05),以及医用蒸馏水4倍稀释(t=-1.9957,P0.05)差异有统计学意义。结论:三碘甲状腺原氨酸TT3S0定标液2倍,4倍稀释方法及医用蒸馏水2倍稀释方法均可以得到较为满意的结果。三碘甲状腺原氨酸(TT3)配套TT3定标液S0可用于标本2倍及4倍稀释。当定标液获取困难,蒸馏水2倍稀释同样可以运用。     

儿童化学发光免疫分析中稀释方法的探讨

目的：探讨儿童化学发光免疫分析中标本量过少时,用怎样的稀释介质以及稀释方法解决这个问题,分析不同的稀释介质产生的基质效应。方法：本实验以儿童常规筛查检测项目血清三碘甲状腺原氨酸（TT3）为例,选取血清样本30例,分别使用美国贝克曼库尔特公司UniCelDX1800Access化学发光免疫分析仪测试药盒三碘甲状腺原氨酸（TT3）配套TT3定标液s0（简称TT3S0）、0．9％氯化钠、医用蒸馏水作为稀释介质进行手工2倍（1：1）及4倍（1：3）后测定。计算稀释测定结果与原始数据的差异,观察基质效应对检测结果的影响。寻找实际工作中可运用的稀释介质和稀释倍数。结果：不同稀释组与原始值之间比较,TT3S02倍（t=-0．7937,P〉0．05）、4倍稀释（t=-0．2503,P〉0．05）,以及蒸馏水2倍稀释（t=-0．2845,P〉0．05）差异均无统计学意义。而0．9％氯化钠2倍（t=-6．4686,P〈0．05）、4倍稀释（t=-3．9842,P〈0．05）,以及医用蒸馏水4倍稀释（t=-1．9957,P〈0．05）差异有统计学意义。结论：三碘甲状腺原氨酸TT3S0定标液2倍,4倍稀释方法及医用蒸馏水2倍稀释方法均可以得到较为满意的结果。三碘甲状腺原氨酸（TT3）配套TT3定标液S0可用于标本2倍及4倍稀释。当定标液获取困难,蒸馏水2倍稀释同样可以运用。     

生态毒理试验中的连续流系统设计及控制

长期连续流试验中,毒物浓度波动主要归因于毒物稀释系统的故障。为了提高毒性数据质量,毒物浓度水平监控是必不可少的.本文对现有连续流试验系统中的毒物稀释器作了改进,采用计量泵输送毒物和稀释水,提高毒物稀释系统的精确度。同时,在连续流试验系统中配置了实时监控系统(RTMS).RTMS由泵、样品室、分析仪器、记录仪等组成.在56d试验中,RTMS随时提供毒物稀释器运行的最新情况,各级毒物浓度变异系数在2.16%-6.13%之间。系统的运行成功为规范中、长期毒性试验提供了技术保证.       

一种新的稀释方法与传统稀释方法的比较

我们建立一种新的连续稀释方法,使用注射器装入金属小棒于磁力搅拌器上连续稀释,标本定量接种,对使用比浊法测定的已知菌浓度的金葡菌、大肠杆菌和绿脓杆菌进行平板活菌计数法,结果与传统的吸管或移液器稀释方法相比后两种方法重复性好,结果准确,无显著差异,但新的稀释方法操作更简便,并经初步烧伤创面定量分析试验证实,效果稳定,值得推广使用。     

氟碳乳剂与右旋糖酐对犬缺血心肌侧支循环供氧的影响

本实验在14只麻醉开胸狗心脏上观察了氟碳乳剂与右旋糖酐稀释血液对心肌耗氧量与供应缺血心肌氧量关系的影响。以左室压力-时间指数(SPTI)作为心肌耗氧量的指标,根据冠脉有效侧支血流量(ECF)、PaO_2和 Hb 浓度计算供应缺血心肌的氧量。实验结果表明,低分子右旋糖酐稀释血液后,SPTI 暂时性轻度增加(稀释后30min 时较对照增加7.1±2.7%,P<0.05,稀释后60min 时增加2.8±1.2%,P>0.05),ECF 明显增多(稀释后30min 时较对照增加58.5±6.1%,P<0.01),缺血区边缘心肌氧供需关系未发生明显变化。氟碳乳剂稀释血液后,SPTI 的变化规律与右旋糖酐稀释后相同(稀释后30min 和60min 时分别较对照增加2.5±0.7%和1.9±0.8%)ECF 和 PaO_2升高(稀释后30min 时分别较对照增加53.9±6.7%和93±8.9%),供应缺血心肌的氧量显著增加,缺血区边缘心肌氧供需矛盾明显改善。     

不同急性失血量和等容稀释对家兔血压心率微血管的影响

本实验以麻醉家兔总血量的１０％、２０％、３０％、４０％和５０％的动脉放血,并以５０％放血后等量输入生理盐水,使血液稀释．结果发现,随着失血度增加和红细胞压积的降低,动脉血压下降,等容稀释后动脉血压明显回升;心率随失血的增加出现先快后慢,等容稀释后变慢更明显．眼结膜微血管随失血量增加血速度变慢,等容稀释后明显加快．眼结膜微血管口径随失血量增加而变大,等容稀释后仍进一步变大．实验提示,急性失血红细胞压积在２５％左右,这时佐以等容血液稀释,保持正常容量,对机体无害而且是有益的．     

生物多样性与传染性疾病的关系: 进展、挑战与展望

在全球生物多样性快速丧失的背景下, 理解生物多样性如何影响传染性疾病风险具有重要意义。大量研究表明, 宿主多样性对传染性疾病可能存在稀释效应(即疾病风险随宿主生物多样性的增加而降低), 但是也有放大效应或者没有影响的证据。本文首先介绍了关于生物多样性与传染性疾病关系的研究进展, 以及该领域的热点研究问题, 包括宿主多样性-疾病关系的格局和空间依赖性、稀释效应的体系依赖性和系统发育稀释效应等。随后,介绍了相关研究伴随的争议和批判, 主要集中在: 稀释效应发生的普遍性、生物多样性-疾病关系实验研究的发表偏好性以及部分疾病生态学家对生物多样性和传染性疾病之间简单数字关系的过分关注。最后指出稀释效应与物种共存、全球变化对稀释效应的影响、进化与稀释效应、稀释效应在政策制定中的应用等领域可能是今后的主要研究方向。     

基于高通量测序的稀释平板计数细菌群落变化研究

【目的】明确平板计数法中不同稀释梯度对土壤细菌数量和组成的影响规律,比较稀释平板计数法和高通量测序研究土地利用方式变化下土壤细菌群落的差异。【方法】针对不同土地利用方式下的4种土壤(次生林、健康蕉园、发病蕉园和水稻土),设置5个土壤悬液10^-1-10^-5稀释梯度开展平板计数,获得平板上可培养细菌富集物并提取总DNA;同时直接提取原位土壤微生物总DNA,高通量测序细菌富集物DNA和土壤总DNA中的16S rRNA基因,研究不同土壤悬液稀释梯度下的可培养细菌群落和背景土壤细菌多样性,明确可培养细菌占土壤总细菌的比例以及多样性差异。【结果】次生林垦殖为蕉园土壤后土壤呼吸增幅最高,细菌数量降幅最高,稀释平板计数与实时荧光定量PCR (real-time fluorescent quantitative PCR)结果一致,但其他土地利用方式变化的稀释平板计数与实时荧光定量细菌数量的结果并不完全一致。连续稀释显著降低了可培养细菌多样性。与原位土壤总细菌相比,土壤可培养细菌群落Chao 1指数降幅高达86%-98%。与土壤悬液稀释10倍(10^-1...     

稀释速率对高浓度酒精连续发酵过程振荡行为的影响

在一搅拌罐和三段管式反应器组成的组合反应器系统中,使用葡萄糖浓度为280g/L,添加5g/L酵母膏和3g/L蛋白胨的底物,在总稀释速率分别为0.032h^-1,0.024h^-1,0.017h^-1,0.012h^-1和0.006h^-1的条件下,考察了稀释速率对高浓度酒精发酵系统振荡行为的影响。结果表明,振荡行为在特定的稀释速率条件下呈现,进而基于数学上的分岔理论,分析了振荡行为发生的可能性及对应的稀释速率范围,并与实验结果进行了比较,在此基础上,讨论了振荡行为对酒精发酵过程的影响。     

A simple diluter for flow-through toxicity studies

An original, simple, and inexpensive diluter for flow-through toxicity studies is described. The diluter is run only by water gravity and has no moving parts. The main units of the device are made of very cheap disposable components and may be mounted without qualified technical assistance. It has neither metal nor any other kind of chemically active parts contacting experimental media. The diluter may be easily modified to study toxicants independently or in mixtures, in fact, as many toxicants as are necessary. When properly calibrated, it does not require further adjustments even during long-term experiments. The main original feature of the diluter described here is its dosing system, which is based on a vacuum air lock. This key system is very simple, reliable, includes neither mechanical nor electrical devices, and ensures adequate accuracy in dosing.     

Technique and Apparatus for Rapid and Inexpensive Enumeration of Bacteria

A foot-operated diluter/dispenser and a projection viewer were developed for use with a rapid bacterial counting technique employing agar droplets. The equipment allows the advantages of the technique to be properly realized and assists many conventional bacteriological tests which may be made at the same time. Significant cost and labor savings are made, with reductions in incubation time, incubator space, and preparative work.     

同柱串联凝胶过凝从重组人肿瘤坏死因子中脱除PEG和盐

A serial gel filtration operation with the combination of G25 and G100 in one column was developed to remove salt and PEG from upper phase rich in recombinant human tumor necrosis factor alpha after simultaneous cell disruption and two-phase aqueous extraction. Buffer exchanging and primary purification were also achieved at same time. The purification factor of 4.4 was obtained with an activity recovery of 97% by one single step of serial operation.     

Preparing Single or Serial Sections of Calcified Bones and Teeth

An apparatus for cutting single or serial sections of calcified bone and teeth consists of a motor-driven shaft on which is mounted one saw (for single section cutting) or a gang (for serial sectioning at one cutting operation). The plastic-embedded specimen is attached to a cylindrical plastic holder which is in turn mounted on the machine and fed into the saw. Prior to cutting the specimen may be oriented in two planes, as well as rotated, with respect to the cutting edge. Single or serial sections made by means of repeated cuts with a single saw, may be 0.3 mm or more thick as determined by the setting of a micrometer screw. For serially sectioning a tooth or bone specimen at one cutting operation, the thickness of the separators between adjacent saws (0.5 mm or more) determines the section thickness. After sectioning, specimens may be ground and polished, with or without reimbedding in fresh plastic.     

Hyperglucagonaemia in the surgical patient.

Twenty-one patients had serial samples of blood taken before, during, and after operation for the measurement of plasma glucagon, plasma insulin, and blood glucose concentrations. A significant rise in plasma glucagon level was noted during the operation. In contrast the plasma insulin concentration fell during the operation and rose in the postoperative period despite hyperglycaemia during and after the operation. These findings show that hyperglucagonaemia is a physiological consequence of a surgical operation and that the relationship of plasms glucagon to plasma insulin is complex.     

Global dynamics of a class of complex valued neural networks

In this paper activation dynamics of a complex valued neural network has been studied. Sufficient conditions for global exponential stability of a unique equilibrium are obtained. Our results show that in the serial mode of operation, the network converges to a stable state.     

Models of production lines with flexible workstations

This article presents models of production line systems with two flexible workstations. Flexible stations have the capability of switching from one operation to another when they become either blocked or starved. The objective is to determine and compare the production rates of serial and parallel arrangements of the workstations. It is shown that, in general, the serial arrangement achieves higher efficiency. Under some specific assumptions, however, both arrangements have the same production rate. An extension of the analysis of two stations to n stations for the parallel case is also presented.     

Das Autoselect-System – ein Automatensystem zur Selektion von Antibiotikaproduzenten. IV. Achtfach-Verdünnungsautomat

As a part of the Autoselect-system an eightfold diluter is described. Cassettes with 64 tubes are placed on the carriage of the machine and moved automatically in eight steps. One of the cassettes is loaded with separated samples in 64 tubes and the other one with 64 empty tubes. When the carriage stops, a defined volume of samples is exhausted by eight pipettes, mounted on a bridge spanning over the ground unit from left to right, and after beeing moved to the second cassette the pipettes deliver the samples into a row of empty tubes. At the same time by eight syringes mounted on both sides of the machine a defined volume of buffer is delivered through tubes and canules. By this way all samples can be diluted in two minutes.     

Das Autoselect-System – ein Automatensystem zur Selektion von Antibiotikaproduzenten. V. Achtfach-Pipettierautomat

An automatic eightfold-pipetter has been developed with the same basic unit as the diluter of the Autoselect-system. The pipetter is fitted with eight pipettes on a bridge over the basic unit. By means of the pipettes a volume of 0.05 ml from eight tubes is exhauseted and delivered in the holes of a test plate. Both the test plate and a cassette with 64 tubes are located on a moving carriage. the test plate on the first floor and the cassette on the ground floor. If the pipettes transfer the samples from the tubes to the holes the distance between the pipettes must be changed by a special device from 20 to 30 mm, because the distance between the holes on the test plate differs from that of the tubes. For the transfer of 64 samples 2 minutes only are needed.