The mechanisms relating to increases in plasma enzymes and isoenzymes in diseases of animals

Changes in plasma or serum enzymes and isoenzymes are useful indicators of tissue damage in many diseases. Enzyme increases are usually related to leakage of enzymes from damaged cells. The amount of increase depends on factors such as the concentration of enzyme in the cells, the rate of leakage of enzyme from cells and the rate of clearance of enzyme from plasma. There are important species variations in the tissue concentrations and plasma clearance rates of enzymes and isoenzymes.     

工蜂胎对小鼠非特异性免疫功能的影响

通过碳粒廓清实验,研究了工蜂胎对机体免疫功能的影响。结果表明:工蜂胎能显著提高ICR小鼠碳粒廓清指数、胸腺质量指数和脾指数。与对照组相比,差异显著(p<0.05)或极显著(p<0.01)。表明工蜂胎具有显著提高机体的非特异性免疫功能的作用。上述药理作用以蜂王胎为对照,结果发现,工蜂胎与蜂王胎的差异不显著(p>0.05)     

基于换算长细比的正交胶合木稳定系数计算方法

正交胶合木(CLT)纵横向层板交叉组坯,纵向层板强度和模量较高,横向层板强度和模量较低,其截面呈强弱相间的条带状结构.当轴心受压构件失稳时,截面剪切变形对CLT稳定承载力的影响不可忽略,故不能采用一般木产品的稳定承载力计算方法.目前我国相关标准中尚无CLT轴心受压构件稳定承载力计算方法.鉴于此,从CLT产品的截面构成特...     

离心泵平衡孔和背叶片对轴向力特性影响

为研究平衡孔和背叶片对低比转数离心泵轴向力特性的影响,选用一台IS80-50-315型离心泵为研究对象,分别对只有平衡孔、只有背叶片及二者皆有、皆无4种方案进行试验与数值分析.结果表明,背叶片对泵水力性能的影响大于平衡孔,且对泵能量损耗起主导作用.在额定工况下,前泵腔内液体压力沿径向具有“阶梯型”变化规律,后泵腔内液体压力近似线性增大,平衡腔内液体压力随流量变化几乎呈直线分布趋势;同一台试验泵中,平衡孔对前泵腔和平衡腔内液体压力影响更大,背叶片对后泵腔内液体压力降低效果更佳.叶轮加背叶片后所受扭矩明显增大,仅有平衡孔时扭矩稍有增加.全流量工况下平衡孔对轴向力的平衡能力优于背叶片;两者共同存在时,平衡轴向力效果最差.     

Implications of Preslaughter Feeding Cues for Broiler Behavior and Carcass Quality

Feed withdrawal management has significant effects on contamination of commercial broiler chickens. The effect of a cue (short period of feed withdrawal) on broiler behavior, carcass yield, and carcass quality (carcass scratches, trimming, condemnations, and fecal contamination) was evaluated using 2,400 female broilers. Cues were applied for 3 consecutive days prior to slaughter by lifting the feeders in each pen for 0, 1, 2, or 4 h. Bird behavior was monitored to determine the effect of the cue on feeding patterns. The effect of the cue on carcass yield and quality (carcass scratches, trimming, condemnations, and internal contamination) at the time of processing was determined.Cueing for 1 (CUE1), 2 (CUE2), and 4 (CUE4) h resulted in an increase in activity at the feeders compared with the control treatment (CUE0); higher activity resulted from longer cues. During the cue, live BW loss was greatest in the CUE4 treatment at 24.8 g. Birds in the CUE1 treatment gained 11.3 g during application of the cue. Uniformity of cecal contents was improved in the CUE4 treatment. No differences in carcass yield among cueing treatments were observed. The incidence of new scratches, a possible entry point for cellulitis infections, was lowest in the CUE0 and CUE4 treatments. Contamination scores were highest in the CUE1 treatment and lowest in the CUE0 and CUE4 treatments.The data suggest that feeding cues of up to 4 h may be used without compromising processing yield or carcass quality. Benefits may be limited to improved uniformity of cecal emptying.     

Effects of Feed Withdrawal Time on the Incidence of Fecal Spillage and Contamination of Broiler Carcasses at Processing

Carcass contamination during processing is an expensive problem for poultry processors. Feed withdrawal (FW) is commonly used to reduce the amount of gut contents prior to slaughter, thereby reducing the probability of contamination. The present study used market aged mixedsex broilers to evaluate the effect of FW time on the incidence of fecal spillage and contamination of broiler carcasses at processing. In order to develop a more simple research protocol for FW, the effects of live haul and holding in stationary crates were compared. Broilers were subjected to 1 of 4 FW times (4, 8, 12, and 16 h) prior to slaughter at a commercial processing plant, in which the incidence of carcass contamination was recorded. Carcass yield and clearance of contents from 8 gut sections were determined. Moisture content of the pooled gut contents was assessed.Shrink increased from 2.1 to 3.3% of pre-FW BW after 4 and 16 h, respectively. Gut weights decreased significantly with every additional 4 h of FW. The incidence of processing plant inefficiencies decreased with increasing FW time. Gut moisture was not correlated with FW time, although moisture of the gut contents was reduced in birds subjected to live haul. Twelve hours of FW resulted in an optimal combination of gut clearance and carcass yield.     

不同工况下轴流泵转子径向力及其压力脉动分析

【目的】研究轴流泵转子所受径向力及内部压力脉动。【方法】采用试验以及ANSYS CFX定常计算的方法,研究了轴流泵的外特性;采用ANSYS CFX软件对轴流泵内部流场进行了非定常计算,研究了不同流量工况下轴流泵内部转子径向力的分布情况及内部不同监测点压力脉动的时域和频域特性。【结果】(1)数值计算的外特性结果与试验结果的趋势基本吻合,数值计算具有较高准确度;(2)转子运动时,内部流场关于转动中心呈现不对称性;(3)3种流量工况下径向力的分布均呈现一定的周期性,小流量工况下瞬态径向力最不稳定,波动较大,设计流量工况下瞬态径向力较小,大流量工况呈现较好的平衡状态;(4)不同流量工况下压力脉动受叶片数影响,主要以叶频为主,且随着频率的增加,压力脉动逐渐减小,说明低频信号是引起压力脉动的主要原因,从整体来看,各监测点压力系数随着流量幅值的增大而逐渐减小,但轮缘进口处变化较快,说明轮缘进口压力脉动受流量变化影响最大。【结论】轴流泵内部转子径向力随流量的增大趋于稳定,不同流量下内部不同点的压力脉动存在明显差异。     

小型拖拉机气门间隙及其调整

详细讲解了气门间隙及其功用,气门间隙过大、过小对柴油机工作的影响和气门间隙的检查调整及调整方法。     

木材锯切技术的发展

简述木材锯切技术所经历的手工期、简单机械期、近代期和现代期及其特点,对各种木材锯切技术进行了分析,结论是零锯料角木工锯子技术整体性能较好,可以实现高质量、高效率、高效益锯切木材.     

The Seismic Shear Capacity of I-Shaped and T-Shaped Reinforced Concrete Structural Walls

There are numerous shear walls with flanges in the high-rise buildings in P.R.China.The shear strength formula for shear walls in Chinese design codes lacks experimental data,while test results in other nations lack aseismatic shear strength test results for shear walls with flanges under axial force.In this paper,we report low-cyclic reverse load test results of shear wall models with large dimensions,one shear wall having an I-shaped cross-section and two with a T-shaped cross-section.We discuss why the aseismatic shear walls of high-rise buildings with large height-to-length ratios have small shear span ratios.We assess the reliability of the shear strength formulary in the Chinese codes for design of shear wall using the international shear wall test results.