Eimeria acervulina: influence of corticosterone-induced immunosuppression on oocyst shedding and production characteristics in broilers, and correlation with a computer simulation model

An experiment was conducted to investigate the effects of immune responsiveness on excretion of oocysts after E. acervulina infection and subsequent effects on production characteristics of broilers (Gallus domesticus). These effects were determined in broilers repeatedly infected with 2.85 x 10(3) oocysts of E. acervulina and treated with various dosages of corticosterone in the diet (0, 10, 20 and 30 p.p.m.). Corticosterone treatment did not have an effect on the peak oocyst excretion, although it was administered from 4 days before initial infection. The number of oocysts excreted shortly after the peak and the length of the excretion period were increased in corticosterone-treated groups. The absence of a difference in peak oocyst excretion was ascribed to the existence of a time-lag between first contact with the parasite and rate of development of protective immunity. In a recently developed computer simulation model this period was assumed to be 5 days. Assuming that immunosuppression, through corticosterone, is only effective when protective immunity is in operation, the results indicate a time-lag of at least a few days, which supports the inclusion of such a time-lag in the computer simulation model. General immunosuppressive effects of the corticosterone treatment, monitored by antibodies and mitogen-induced lymphocyte stimulation confirmed that immunosuppression occurred shortly after medication started. Infection did not have a significant influence on production characteristics in animals without dietary corticosterone. However, with increasing corticosterone levels the negative effects of infection on production also increased.     

Temporary results only in electroconvulsive therapy in therapy-resistant depression; retrospective study

OBJECTIVE: To evaluate the use and efficacy of electroconvulsive therapy (ECT) in refractory major depression according to DSM-III-R criteria, and to look for factors predicting response in the acute phase and the occurrence of relapse or recurrence after recovery. DESIGN: Retrospective. SETTING: University Hospital Rotterdam, The Netherlands. METHODS: Of all patients who received ECT between January 1988 and July 1993 data were collected by study of clinical records and of information by treating physicians after discharge. Every patient was visited once, or received an outpatient department appointment, to obtain informed consent, take a follow-up history and evaluate social functioning by scoring Global Assessment of Functioning and Sickness Impact Profile rating scales. RESULTS: 35 patients received ECT. In clinical practice, the guidelines of the Netherlands Psychiatric Association were not violated; most patients had received adequate pharmacological pretreatment before the decision to start ECT was made. Two patients died in hospital (not from ECT). In the acute phase 25 of the 33 patients still alive upon discharge showed good recovery. Seven of these suffered relapse within six months. The number of patients with a return of depressive symptoms rose to 12 by the end of the first year of follow-up. Sociodemographic variables and treatment characteristics did not appear to influence the result of treatment in the acute phase, nor the occurrence of relapse or recurrence. With less intensive pre- and post-ECT drug treatment the chances of relapse were increased. CONCLUSIONS: ECT is an effective treatment in the acute phase of a depression. Results after a longer period of follow-up are less satisfactory.     

Non-hierarchical logistic models and case-only designs for assessing susceptibility in population-based case-control studies

Mechanisms for the abnormal copper (Cu) accumulation in the liver of LEC rats were examined using primary cultured liver parenchymal cells prepared from mutant LEC rats and those from control LEA rats (original strain). The Cu and metallothionein (MT) mRNA levels in the liver of LEC rats were caused to decrease to the same levels as those of LEA rats by removing Cu in vivo selectively with tetrathiomolybdate. Cu was taken up by LEC rat cells to the same extent as LEA rat cells by exposure to low medium Cu and to a higher extent by exposure to high medium Cu, while the MT mRNA level in LEC rat cells increased dose-dependently at a much higher rate than that in LEA rats. MT mRNA levels in both cells were comparable by exposure to cadmium, zinc and dexamethasone. The results indicate that expression of MT mRNA is selectively enhanced by Cu in LEC cells despite the fact that uptake of Cu is comparable with normal cells.     

High-T/sub 0/ strain-compensated InGaAsSb-AlGaAsSb quantum-well lasers emitting at 2.43 /spl mu/m

Strain-compensated InGaAsSb-AlGaAsSb quantum-well (QW) lasers emitting near 2.5 /spl mu/m have been grown by solid-source molecular beam epitaxy. The relatively high arsenic composition causing a tensile strain in the Al/sub 0.25/GaAs/sub 0.08/Sb barriers lowers the valence band edge and the hole energy level, leading to an increased hole confinement and improved laser performance. A 60% external differential efficiency in pulsed mode was achieved for 1000-/spl mu/m-long lasers emitting at 2.43 /spl mu/m. A characteristic temperature T/sub 0/ as high as 163 K and a lasing-wavelength temperature dependence of 1.02 nm//spl deg/C were obtained at room temperature. For 2000 /spl times/ 200 /spl mu/m/sup 2/ broad-area three-QW lasers without lateral current confinement, a low pulsed threshold of 275 A/cm/sup 2/ was measured.     

微胞囊技术及产品F-500多功能灭火剂

介绍了微胞囊技术及产品F-500的灭火原理和优势。     

高功率二极管泵浦固体激光技术和应用前景的分析

文章对高功率二极管泵浦固体激光器的若干关键技术，包括激光二极管和增益介质，泵浦，耦合和冷却技术，以及光学谐振腔等作了详细的分析。     

高炉冷却技术的开发与应用

通过对中小型高型炉寿命的分析，结合河北省冶金设计院高炉设计的实践经验，总结了高炉冷却设备寿命短的原因，并提出冷却设备在材质和结构上的改进措施。     

基金最佳使用计划

本文给出了基金存款策略的数学模型.对于基金M使用n年的情况而言,首先把M分成n份,其中第i(1≤i≤n)份存款xi存期为i年,那么只有当第i(i ≤n-1)份资金按最佳存款策略存款到期后的本息和等于当年的奖学金数,并且第n份资金按最佳存款策略存款n年后的本息和等于原基金M与当年的奖学金数之和时,每年发放的奖学金才能达到最多.通过求解此模型,我们得到了基金的最佳存款策略,并求出了在n=10年,M=5000万元的情况下,基金的最佳使用方案.在可存款也可购买国库券时,采取一种转化方法,将国库券购买情况转化为相应年期的定期存款,结合问题(一)即可求得在n=10年,M=5000万元的情况下,基金的最佳使用方案;在第三年校庆时奖学金数额比其它年度多20%的问题的分析方法和模型的解决方法与前相同.     

干粉灭火剂浅论

前言 :干粉灭火剂 (Dry fire extinguishing powder、Drychemical、Fire extinguishent)始于十九世纪末 ,二十世纪三十年代美国 Ansul公司首先开发出以碳酸氢钠为基料的干粉灭火剂 ,是最早应用于消防科技领域的干粉灭火剂。干粉灭火剂由一种或多种具有灭火能力的细微无机粉末组成 ,粉末的粒径大小及其分布对灭火效果有很大的影响 ,按照干粉灭火范围可划分为三类 :ABC类 :磷酸一铵 ;BC类 :碳酸氢钠、碳酸氢钾、氯化钾、氯化钠、硫酸钾、硫酸铵、monnex;D类 :氯化钠、碳酸氢钠、石墨灭火剂。干粉灭火剂与水、泡沫、二氧化碳等相比 ,在灭火…