论改善高层建筑的扭转反应

本文从扭转反应的概念与改善高层建筑扭转反应的原则入手，阐述了控制扭转反应的理论基础，并且就高层建筑结构扭转反应控制措施进行了研究，以期能够对控制高层建筑结构的扭转反应起到积极作用。     

家蚕5龄幼虫蛋白水解酶的最适反应温度和pH值

调查了家蚕(华峰×雪松)5龄幼虫的血液、消化液以及脂肪体蛋白水解酶的反应条件,发现其最适反应温度均在37℃左右,最适反应pH分别为80、98和68左右。血液蛋白水解酶在pH68~98之间其活力变化不大。     

敌蚜胺中毒检验初报

以敌蚜胺患病鸡的嗉囊和肌胃黏液、内容物为材料,用乙醚、甲醇、乙酸乙脂、二氯甲烷(1∶2)对检材作处理,结果表明:微晶反应、异羟肟酸铁反应、纳氏试剂反应、硫靛反应、硫靛反应产物的薄层层析法对敌蚜胺的检出率高,用时短,并能够准确定性。     

甜菜碱合成反应条件的研究

本实验研究了以氯乙酸、烧碱和三甲胺为原料化学合成甜菜碱的反应条件。结果发现,甜菜碱合成反应在25～40℃条件下能很快进行,反应1h产率即可达到最大值96%左右,且反应温度没有必要高于40℃。     

新型防霉剂双乙酸钠的制备

采用醋酸与碳酸钠为原料,水为溶剂一步法合成双乙酸钠。实验考察了原料配比、反应温度、反应时间、溶剂用量等因素对反应的影响,确定了适宜的反应条件,产品质量达到FAO/WHO标准,双乙酸钠总收率达97%以上。     

热应激诱导畜禽氧化应激、热休克反应与免疫和炎症反应的机制及营养调控措施

热应激会引起畜禽机体代谢增强,从而引起活性氧(ROS)的过量产生而发生氧化应激;氧化应激可启动热休克反应,上调热休克蛋白(HSPs)的转录与表达;ROS和HSPs两者都可以激活核转录因子-κB(NF-κB)进而启动免疫和炎症反应。本文综述热应激引起畜禽氧化应激反应、热休克反应与免疫炎症反应的机制及三者之间的相互关系,并在此基础上总结一些营养调控缓解热应激的措施,以期认识这3种反应在畜禽热应激营养调控过程中的意义。     

牛型结核菌素皮内变态反应对比试验

采用农业部成都药械厂（以下简称成都药械厂）和中国兽药监察所（以下简称中监所）生产的牛型提纯结核菌素（PPD）在两个奶牛场作皮内变态反应的对比试验。结果表明,两家的PPD反应程度不一,成都药械厂的反应大,中监所的反应小。     

剂量反应试验的正确试验设计与数据分析

通过对两个例子的分析说明了剂量反应试验数据分析中的不恰当分析方法，阐述了如何根据试验目的正确地进行剂量反应试验设计，给出了不同类型的剂量反应试验数据的正确分析和结果表示方法，并同时指出了对此类数据分析时一些需要注意的问题。     

氧化时长对不同油脂过氧化指标的影响研究

<正>目前人们普遍认为,油脂过氧化后可能含有有毒的脂质过氧化产物,并且可以诱导动物产生氧化应激(Kubow,1992)。饲料中脂质过氧化反应从自由基或单线氧开始,发生一系列的自身催化自由基反应,这些自动氧化反应引起脂质断裂,形成大量的脂质过氧化产物,     

寄生虫感染的非特异性防卫机制

一般在初次寄生虫感染后，宿主体首先出现的应答是一种无有效抗原特异性的反应(no effective antigen-specific response)，通常可持续数周时间。此时，在宿主体内可出现一系列连锁反应，由各种体液因子介导，并有吞噬细胞参与其间，有局部反应，也有全身性反应。     

美国白蛾的发生规律与综合治理

美国白蛾为外来入侵种,现已扩散蔓延到辽宁、河北、天津、山东、陕西、上海等省市.美国白蛾是食叶性害虫,桑树是其喜食树种,对桑树生长和桑叶产量的影响很大.本文介绍了美国白蛾的发生规律、成灾原因及其相关的综合治理措施.     

奶牛源化脓隐秘杆菌的分离鉴定及其毒力基因的检测

本研究旨在分离鉴定来自北京某奶牛场死亡奶牛肺脏的1株疑似病原菌CVCC 3982,并测定其致病性。通过分离培养获得疑似病原菌,采用Biolog鉴定系统和16S rDNA序列分析对其进行了鉴定,人工接种CD-1小鼠测定了其致病性,合成引物对其主要毒力基因进行了检测。结果显示,该疑似病原菌为革兰氏阳性杆菌,β溶血,Biolog鉴定结果显示其为化脓隐秘杆菌,其16S rDNA序列与化脓隐秘杆菌模式菌株NCTC 5224的同源性达100%,系统发育分析显示其与化脓隐秘杆菌处于同一分支。腹腔注射该菌可致小鼠死亡。分离菌株基因组中含有溶血素(PLO)基因,神经氨酸酶H(NanH)基因,神经氨酸酶P(NanP)基因,菌毛基因(fimA、fimC和fimE),但缺失胶原结合蛋白(CbpA)基因和菌毛fimG基因。结果表明该分离菌株为化脓隐秘杆菌且具有致病性。     

巴音布鲁克高寒草地几种公害物综合安全的研究

采用综合安全评估法,对巴音布鲁克高寒草地六六六、敌敌畏、铅和砷的综合安全予以评估,结果表明：巴音布鲁克高寒草地土壤、地表水、饲草和肉羊中,六六六、敌敌畏和砷的生态、经济和社会综合安全率均为100%,其综合安全居于高级安全状态水平,铅的生态、经济和社会综合安全率均为94.70%,其综合安全居于中级偏上安全状态;六六六、敌敌畏、铅和砷总综合安全率达98.57%,总综合安全居于中级偏上安全水平。     

Synthetic maternal pheromone stimulates feeding behavior and weight gain in weaned pigs

One hundred and forty-four pigs were used to determine the effects of a putative synthetic maternal pheromone on behavior and performance of weanling pigs. Each pen of weaned pigs contained three pigs that were given free access to water and feed. Pigs were videotaped in time lapse for 48 h after weaning and weekly body weights and feed disappearances were recorded for 4 wk. Treatments included: a) control (vehicle applied), b) 30 mL of synthetic pheromone applied to the feeder, or c) 10 mL of synthetic pheromone applied to each of three pigs' snouts. Pigs exposed to the synthetic pheromone spent more (P < 0.05) time with their heads in the feeder and less (P < 0.05) time drinking, lying down, or engaged in agonistic behaviors than control pigs. Pigs exposed to the synthetic pheromone were more (P < 0.05) active during the 48-h period of video taping than control pigs. Pigs exposed to the synthetic pheromone (either on the feeder or their snout) had increased (P < 0.01) average daily gain (ADG) and better (P < 0.01) feed:gain ratio than control pigs over the 28-d postweaning period. In conclusion, the putative synthetic pheromone, applied once at weaning, stimulated apparent feeding behaviors, and reduced fighting and apparent drinking behaviors during the first 48 h after weaning. ADG and feed:gain ratio were improved by application of the putative synthetic pheromone either directly on the feeder or when painted on the pigs' snouts. Olfactory signals can modulate adaptation to the postweaning environment in ways that may improve pig performance and welfare.     

天然培养基与合成培养基灭菌方式的研究

试验选择5种天然培养基和5种合成培养基。每类培养基分装到20个三角瓶中,天然培养基分为2组(天然培养基Ⅰ组和Ⅱ组),合成培养基分为2组(合成培养基Ⅰ组和Ⅱ组)。天然培养基Ⅰ组、合成培养基Ⅰ组和天然培养基Ⅱ组、合成培养基Ⅱ组,在高压灭菌15min后,分别自然冷却降至压力为0和慢慢放气降至压力为0,然后放置培养箱中培养,并记录污染情况。结果显示,天然培养基适合自然降压灭菌,而合成培养基适合慢慢放气降压灭菌。     

RAPD技术及其在牧草研究中的应用

简要介绍了RAPD分子标记技术的原理和特点以及该技术在牧草遗传多样性分析、亲缘关系研究、品种及杂种纯度鉴定中的应用,同时阐述了它在牧草研究领域中存在的问题及其展望。     

维生素K生产工艺进展

维生素K是重要的饲料添加剂。介绍了维生素K的种类、性质与生理意义。着重综述了维生素K的生产工艺。探讨了化学合成法生产维生素K的废液的治理途径,论证了微生物发酵法生产维生素K的可行性。     

Unilateral degeneration of retina and optic nerve in Fischer-344 rats

Unilateral degeneration of the retina and optic nerve was observed among Fischer-344 (F-344) rats fed a semi-purified synthetic feed. Further studies were conducted using standard cereal-based and synthetic diets. Beginning at 4 weeks of age, all experimental rats (169 F-344 rats) were fed various diets and were examined for morphologic and functional changes in the retina and optic nerve. No ocular lesions were observed in any F-344 rats prior to 21 weeks of age, whether fed a synthetic diet or a standard diet; however, approximately 16% (13/86) of the F-344 rats examined between 57 and 64 weeks of age developed unilateral degeneration of the retina and optic nerve. On the other hand, the F-344 rats fed the synthetic diet developed the degenerative lesions by 30 weeks of age, while the F-344 rats fed the standard diet did not develop lesions over this shorter time period. Degenerative changes of the affected retinas and optic nerves were closely related with functional abnormalities evaluated by electroretinogram and visual evoked potentials. In contrast with the F-344 rats, Long-Evans rats that were fed either the synthetic or standard diet up to the age of 68 weeks (77 rats) did not develop the ocular lesions. There was no apparent relationship of the development of the lesions with dietary modification, toxicity or trauma; thus, these observations appear to indicate that spontaneous unilateral degeneration of the retina and optic nerve occurs in F-344 rats and that these ocular lesions may be accelerated by the feeding of certain semi-purified synthetic diets.     

Effect of Synthetic Colloids on Refractometric Readings of Total Solids

Veterinary patients are treated with colloid solutions for plasma volume expansion and maintenance of plasma colloid oncotic pressure (COP). In practice COP is usually extrapolated from measurement of albumin, total protein, or refractometric total solids (TS) as an estimate of total protein. The objective of this study was to determine if refractometer readings accurately reflect levels of synthetic colloid in the blood. Serial dilutions of synthetic colloids Dextran 70 and hetastarch into 2.5% and 5% human serum albumin (HSA) were prepared, and COP and TS measurements were performed. Synthetic colloids were found to produce a significant increase in measured COP, without a significant change in refractometric TS readings. Measured COP correlated well with concentration of synthetic colloid. In clinical patients, treatment of decreased COP with synthetic colloids should be monitored by direct measurement of COP or by observing resolution of clinical signs of hypovolemia or edema. (Vet Emerg & Crit Care, 1998; 8: 21–26)     

Volatile fatty acids in the rumen of sheep fed a synthetic diet

A trial was conducted with wethers to study the effect of the administration of a synthetic diet (composition: 30.125% starch, 30.125% sucrose, 25% cellulose, 5.25% urea, 8.125% mineral supplement, 1.25% maize oil and 0.125% cholinechloride) upon rumen fermentation. The adaptation to the synthetic diet lasted three months, the proportion of the synthetic diet increasing every week (by 10%) to the detriment of a traditional diet (composition: 0.5 kg meadow hay, 0.3 kg barley, 0.2 kg wheat bran, salt and straw ad libitum). In the 10th week the animals consumed 0.5 kg granular synthetic diet, 0.2 kg cellulose flakes and 0.01 kg polystyrene. After three weeks of the administration of the fully synthetic diet, the rumen fluid was sampled after morning feeding in intervals of 0, 1, 3, 5 and 7 hours. In the dynamics of fermentation, statistically significant differences were found only in isobutyric and isovaleric acid between the 0th and 1st and between the 5th and 7th hours (P less than 0.05--P less than 0.001). The data for all the time intervals were recalculated to average values. These were as follows: total volatile fatty acids 63.03 mmol/l, acetic acid 51.00 mol%, propionic acid 26.75 mol%, butyric acid 19.43 mol%, isobutyric acid 0.91 mol%, isovaleric 1.27 mol%, valeric acid 0.62 mol%, energy efficiency of VFA production 78.23%. The obtained data are confronted with literary data on synthetic diets which contained urea and various energy sources.