白足蚜小蜂对桃蚜的取食和寄生功能反应及搜寻效应

为评估白足蚜小蜂Aphelinus albipodus对桃蚜Myzus persicae的防控效果,在室内测定了白足蚜小蜂对不同发育阶段桃蚜的功能反应和搜寻效应,并对种内干扰和分摊竞争强度进行了比较。结果表明:白足蚜小蜂对不同发育阶段桃蚜的取食量和寄生量均随着蚜虫密度增加而增加,取食量和寄生功能反应均符合HollingⅡ模型。白足蚜小蜂对桃蚜的理论最大取食量2.809头,瞬时攻击率0.218,处理时间0.023 d;白足蚜小蜂对3～4日龄桃蚜寄生量最大,为47.62头,寄生瞬时攻击率0.723,处理时间0.021 d。搜寻效应均随蚜虫密度的增加而下降,且与蚜虫密度呈负相关。白足蚜小蜂个体之间存在种内干扰作用,随着自身密度增加,单头寄生率相对下降,分摊竞争强度增大,干扰效应符合Hassell-varley模型。由功能反应、种内干扰等指标可见白足蚜小蜂对桃蚜具有较好的防控作用。     

Cardiovascular effects of sevoflurane in Holstein calves

Objective The purpose of this study was to determine the cardiovascular effects of sevoflurane in calves. Study design Prospective experimental study. Animals Six, healthy, 8–12‐week‐old Holstein calves weighing 80 ± 4.5 (mean ± SEM) kg were studied. Methods Anesthesia was induced by face‐mask administration of 7% sevoflurane in O₂. Calves tracheae were intubated, placed in right lateral recumbency, and maintained with 3.7% end‐tidal concentration sevoflurane for 30 minutes to allow catheterization of the auricular artery and placement of a Swan‐Ganz thermodilution catheter into the pulmonary artery. After instrumentation, administration of sevoflurane was temporarily discontinued until mean arterial pressure was > 100 mm Hg. Baseline values were recorded and the vaporizer output increased to administer 3.7% end‐tidal sevoflurane concentration. Ventilation was controlled to maintain normocapnia. The following were recorded at 5, 10, 15, 30 and 45 minutes after collection of baseline data and expressed as the mean value (± SEM): direct systolic, diastolic, and mean arterial blood pressures; cardiac output; mean pulmonary arterial pressure; pulmonary arterial occlusion pressure, heart rate; and pulmonary arterial temperature. Cardiac index and systemic and pulmonary vascular resistance values were calculated using standard formulae. Arterial blood gases were analyzed at baseline, and at 15 and 45 minutes. Differences from baseline values were determined using one‐way analysis of variance for repeated measures with post‐hoc differences between mean values identified using Dunnet's test (p < 0.05). Results Mean time from beginning sevoflurane administration to intubation of the trachea was 224 ± 9 seconds. The mean end‐tidal sevoflurane concentration at baseline was 0.7 (± 0.11)%. Sevoflurane anesthesia was associated with decreased arterial blood pressure at all sampling times. Mean arterial blood pressure decreased from a baseline value of 112 ± 7 mm Hg to a minimum value of 88 ± 4 mm Hg at 5 minutes. Compared with baseline, arterial pH was decreased at 15 minutes. Pulmonary arterial blood temperature was decreased at 15, 30 and 45 minutes. Arterial CO₂ tension increased from a baseline value of 43 ± 3 to 54 ± 4 mm Hg (5.7 ± 0.4 to 7.2 ± 0.3 kPa) at 15 minutes. Mean pulmonary arterial pressure was increased at 30 and 45 minutes. Pulmonary arterial occlusion pressure increased from a baseline value of 18 ± 2 to 23 ± 2 mm Hg at 45 minutes. There were no significant changes in other measured variables. All calves recovered from anesthesia uneventfully. Conclusion We conclude that sevoflurane for induction and maintenance of anesthesia was effective and reliable in these calves and that neither hypotension nor decreased cardiac output was a clinical concern. Clinical relevance Use of sevoflurane for mask induction and maintenance of anesthesia in young calves is a suitable alternative to injectable and other inhalant anesthetics.     

用COD值定量判断亚麻脱胶终点的探讨试验

亚麻脱胶终点的判断一直没有一种定量的方法。实验研究表明,根据物量平衡原理,研究脱胶过程中COD值随时间的变化规律,得出脱胶终点时的COD值范围,可以作为一种定量判断脱胶终点的方法。通过显微镜检验,该方法与传统方法基本相符。     

持续、低剂量金霉素对肉仔鸡免疫机能的抑制作用研究

270只Abore Acre商品代肉用公鸡随机分成3组，金霉素在饲料中添加水平分别为0、50只和150mg/kg，研究饲用金霉素对肉仔鸡法氏囊、脾脏和胸腺等免疫器官发育、以及免疫反应的影响。结果表明50mg/kg的金霉素对肉仔鸡脾脏和21日龄的胸腺无明显抑制作用，对T、B淋巴细胞转化率也无明显抑制作用（P＜0.05），而且显著促进法氏囊的萎缩（P＜0.05）。金霉素对T淋巴细胞转化率有明显的直接抑制作用；50mg/kg和150mg/kg的金素对BAS特异性抗体的产生均有显著的抑制作用（P＜0.01）。研究结果表明，持续、低剂量和金霉素对肉 鸡免疫器官发育和免疫应答具有显著的抑制作用，抑制作用随剂量增加而加强，150mg/kg的金霉素对肉仔鸡具有显著促生长作用。     

Quantum-confined stark effect in single CdSe nanocrystallite quantum dots

The quantum-confined Stark effect in single cadmium selenide (CdSe) nanocrystallite quantum dots was studied. The electric field dependence of the single-dot spectrum is characterized by a highly polarizable excited state ( approximately 10(5) cubic angstroms, compared to typical molecular values of order 10 to 100 cubic angstroms), in the presence of randomly oriented local electric fields that change over time. These local fields result in spontaneous spectral diffusion and contribute to ensemble inhomogeneous broadening. Stark shifts of the lowest excited state more than two orders of magnitude larger than the linewidth were observed, suggesting the potential use of these dots in electro-optic modulation devices.     

Masson三色染色与HE染色在豚鼠牙齿组织石蜡切片中的比较研究及应用

针对牙齿组织形态学研究的难点,选择适宜固定液,用EDTA-2Na进行脱钙,完成了牙齿组织石蜡切片的制作。通过确定染色程序及各种染料的最佳作用时间,分别利用Masson三色染色法、传统的苏木精和伊红（HE）染色法对牙齿组织切片进行了染色观察。染色结果表明,与HE染色法相比,Masson三色染色更能使牙齿的各主要成分以不同颜色显现出来,色彩对比鲜明,亮丽润眼,为牙齿组织生理及病理组织形态学研究奠定了基础。针对机体中硬组织的相似特性,该试验方法可以在骨骼、软骨等硬组织的形态学研究中参考、改进并推广使用。     

Observations on blood coagulation after snakebite in dogs and cats

Blood samples from 13 cases of snakebite, 6 in dogs and 7 in cats, were tested for activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrin/fibrinogen degradation products (FDP). Four cases were tested for fibrinogen concentration. Based on the results of a commercially available ELISA test, 9 cases were caused by tiger snakes (Notechis scutatus) and 1 case by a brown snake (Pseudonaja textilis). Three other cases had clinical signs and increased creatine phosphokinase values which suggested tiger snake envenomation. Although the period post-envenomation varied, results indicated a marked prolongation of the APTT and PT in 5 of 6 dogs. Three of these 5 dogs also had increased FDP values and 3 (of 3 examined) were hypofibrinogenaemic. Clinical manifestations of this coagulopathy were: haematoma formation after venepuncture (3 cases), gingival petechiae (1 case) and hyphaema (1 case). In contrast, there was minimal or no prolongation of the APTT and PT values, and no increase in FDP, in all 7 cats. Furthermore, no cat exhibited clinical signs of a coagulopathy.     

舒泰对野生猕猴麻醉效果的观察

利用舒泰50(替来它明和唑拉西泮合剂)对36只野生猕猴按(5.79±1.28)mg/kg的剂量肌肉注射进行麻醉,麻醉期间对镇痛、镇静、肌松、呼吸、心率、血压、体温及血氧饱和度等指标进行监测.结果显示:舒泰对猕猴的诱导期为(2.72±1.72)min,平均诱导效果判定为"极好",麻醉期间体温为(38.74±0.46)℃,...     

不同湿度和氨水平对肉仔鸡抗氧化性能及肉品质的影响

本研究旨在探讨鸡舍内不同湿度和氨浓度对肉仔鸡机体抗氧化性能和肉品质的影响.试验选用健康、体质量相近的21日龄AA雄性肉仔鸡192只,随机分为2组.一组为高氨组(暴露于70 mg·kg-1氨气,H),另一组是低氨组(暴露于30 mg·kg-1氨气,L).其中每一组的一半分别置于60％湿度(对照组,C),另一半置于35％湿度(处理组,T),这样组成4个试验组,对照1:60％湿度+30 mg·kg-1氨水平组(C+L)、对照2:60%湿度+70 mg·kg-1氨水平组(C+H)、处理1:35％湿度+30 mg·kg-1氨水平组(T+L),以及处理2:35％湿度+70 mg· kg-1氨水平组(T+H),试验期21 d.试验结束时测定肉仔鸡生产性能,血液及肌肉抗氧化性能和肉品质相关指标.试验结果表明,高氨(70 mg· kg-1)水平显著降低肉仔鸡结束体质量,平均日采食量,日增体质量,血液及肌肉中总抗氧化力及肉仔鸡宰后45 min时的胸肌a*值(P＜0.05);增加了胸肌存放5d时硫代巴比妥酸反应物水平(TBARS)含量,胸肌滴水损失率,宰后45 min时的胸肌b*值(P＜0.05)和L*值(P=0.054)及肌肉剪切力(P=0.075).低湿(35％相对湿度)处理降低了肉仔鸡试验结束体质量(P＜0.05),平均日采食量(P＜0.05)及平均日增体质量(P=0.072),胸肌中超氧化物歧化酶及谷胱甘肽过氧化物酶活性(P＜0.05)及宰后45 min时的胸肌L*值(P=0.053);增加了肌肉剪切力(P=0.057)和胸肌存放5及7d时的TBARS含量(P＜0.05).与低氨对照组(C+L)相比,高氨低湿组处理组(T+H)肉仔鸡的试验结束体质量、平均日采食量、平均日增体质量、血清总抗氧化力、胸肌中总超氧化物歧化酶及谷胱甘肽过氧化物酶活性,胸肌宰后45 min a*值均显著降低(P＜0.05),而宰后5及7d肌肉中TBARS含量、肌肉中滴水损失及肌肉剪切力均显著提高(P＜0.05).本研究结果揭示肉仔鸡舍内高氨(70 mg·kg-1)及低湿度均显著降低了肉仔鸡生产性能、机体抗氧化能力及肌肉品质,且低湿度环境加剧了高氨的不良影响.