Quantitation of adenine nucleotides in equine colonic mucosal tissue using high performance liquid chromatography.

The objectives were to use high performance liquid chromatography (HPLC) to validate an established method for adenine nucleotide separation in equine colonic mucosal tissue, to determine the inherent variability in the tissue and extraction method, and to determine the stability of ATP, ADP, and AMP in the tissue with time. Equine colonic mucosal tissue obtained from a single horse was immediately submersed in liquid nitrogen, and stored at -70 degrees C. Samples were lyophilized, extracted, and separated by HPLC. The limit of quantitation was 0.05 microg/mL. The coefficient of variation for the instrument was less than 10% for all nucleotides measured. When the tissue was not homogenized prior to sampling, there were significant differences in adenine nucleotide content between samples. However, when the tissue was homogenized prior to analysis, these differences were no longer significant. There was no significant decrease in ATP, ADP, or AMP content over a 54-day analysis period.     

Transmission of porcine reproductive and respiratory syndrome virus from persistently infected sows to contact controls.

The objective of this study was to determine if porcine reproductive and respiratory syndrome virus (PRRSV) could persist in non-pregnant sows and if persistently infected sows could transmit virus to naive contact controls. Twelve PRRSV-naive, non-pregnant sows (index sows) were infected with a field isolate of PRRSV and housed in individual isolation rooms for 42 to 56 days postinfection. Following this period, 1 naive contact sow was placed in each room divided by a gate allowing nose-to-nose contact with a single index sow. Index sows were not viremic at the time of contact sow entry. Virus nucleic acid was detected by polymerase chain reaction, and infectious virus was detected by virus isolation in sera from 3 of the 12 contact sows at 49, 56, and 86 days postinfection. All 3 infected contacts developed PRRSV antibodies. Virus nucleic acid was detected in tissues of all of the 12 index sows at 72 or 86 days postinfection. Nucleic acid sequencing indicated that representative samples from index and infected contacts were homologous (> 99%) to the PRRSV used to infect index sows at the onset of the study. This study demonstrates that PRRSV can persist in sows and that persistently infected sows can transmit virus to naive contact animals.     

红曲霉色素的提取

本实验确立了一种新的红曲霉色素提取方法:以红曲米为原料,乙醇为提取剂,得到的提取液再以正己烷提取分离。结果表明,此法所得的红曲霉色素是水溶性的,宜于用作食品添加剂。此外,还对影响提取的因素进行了探讨,并提供了最佳提取方案。     

Outcome of limb amputations in wapiti: 13 cases (1995-2001).

The object of this investigation was to determine the outcome of limb amputation in wapiti. Medical records of 13 wapiti that underwent limb amputation were reviewed to determine age, weight, sex, injury preceding amputation, limb amputated, amputation location, length of hospital stay, complications, and outcome. Ages ranged from 3 months to 8 years and weights from 70 kg to 280 kg. All animals were female. Eleven animals sustained catastrophic long bone fractures prior to amputation. Five animals had front limb amputations and 8 had hind limb amputations. Of these animals, 1 with a front limb amputaiton and 5 with hind limb amputations survived. Postsurgical inability to stand is associated with hospitalization of > 1 day. Of the 13 wapiti reviewed, 5 with hind limb amputations have produced and reared offspring. Hind limb amputation can be considered a viable alternative to euthanasia when catastrophic orthopedic injuries occur in female wapiti.     

离心式压缩机喘振问题分析

当压缩机内气体的流量较低时,气体容易出现旋转脱离现象,导致压缩机不能正常工作,采取增加压缩机内部液体的流量,在出口处设置单向阀防止气体倒流等措施,可有效地防止喘振的发生,保证输气管道的正常运行.     

河北坝上农田垄向对土壤风蚀的影响

在河北省坝上选择试验区 ,利用移动式风洞研究了农田起垄方向对土壤风蚀的影响。结果表明 ,农田起垄方向对土壤风蚀具有影响作用 :垄向与风向成 0°时风蚀量最大 ,90°时风蚀量最小 ;在 15m·s-1风速和 3cm表土含水率为 4 5 %的条件下 ,垄向与风向成 0°时的风蚀量为 90°时的 4 8倍。为减轻土壤风蚀危害 ,在河北坝上地区农田起垄的方向宜采用与自然风向NW (西北风向 ,315°)成 90°,即东北方向 4 5°。     

压力实时监测法在管道泄漏检测中的应用

检测输油管道漏油的方法很多，介绍了通过压力实时监测确定输油管道漏油点方法，以及实际应用情况。实践证明，通过压力实时监视确定输油管道漏油点的方法在实际输油运行中是切实可行的。     

PRRSV弱毒细胞疫苗与灭活疫苗生殖道黏膜免疫效果观察

应用组织学方法比较观察了猪繁殖与呼吸综合征病毒(PRRSV)弱毒细胞疫苗与灭活疫苗生殖道黏膜免疫的效果。试验选用5月龄长白×大约克夏二元杂交母猪18头。PRRSV弱毒细胞疫苗和灭活疫苗通过生殖道黏膜免疫接种。结果表明PRRSV弱毒细胞疫苗生殖道黏膜接种组母猪的子宫黏膜上皮内淋巴细胞数较灭活疫苗生殖道黏膜免疫接种组和对照组母猪显著减少(P<0.01);而且子宫黏膜上皮变矮变薄,变得有些不规则。灭活疫苗生殖道黏膜接种组母猪子宫黏膜上皮内淋巴细胞数与对照组母猪间差异不显著(P>0.05)。本试验结果显示PRRSV弱毒细胞疫苗经生殖道黏膜免疫接种则对生殖道黏膜上皮内淋巴细胞产生抑制作用。说明PRRSV弱毒细胞疫苗和灭活疫苗经生殖道黏膜免疫效果不理想     

提高半湿润地区杂交玉米种子发芽率的有效措施

清水县位于甘肃省东南部,介于34°32′～34°58′N、105°45′～106°30′E之间,属陇中南部半湿润区,年降水量662mm左右,降水主要集中在7～9月份,占年降水量的55%.清水县城关川区中晚成熟玉米品种的生长期是从4月下旬后期到9月下旬后期,大致148d左右.