Comparison of three feline leukaemia virus (FeLV) point-of-care antigen test kits using blood and saliva

Feline leukaemia virus (FeLV) can be a challenging infection to diagnose due to a complex feline host-pathogen relationship and occasionally unreliable test results. This study compared the accuracy of three point-of-care (PoC) FeLV p27 antigen test kits commonly used in Australia and available commercially worldwide (SNAP FIV/FeLV Combo, Witness FeLV/FIV and Anigen Rapid FIV/FeLV), using detection of FeLV provirus by an in-house real-time polymerase chain reaction (qPCR) assay as the diagnostic gold standard. Blood (n = 563) and saliva (n = 419) specimens were collected from a population of cats determined to include 491 FeLV-uninfected and 72 FeLV-infected individuals (45 progressive infections [p27 and qPCR positive], 27 regressive infections [p27 negative, qPCR positive]). Sensitivity and specificity using whole blood was 63% and 94% for SNAP Combo, 57% and 98% for Witness, and 57% and 98% for Anigen Rapid, respectively. SNAP Combo had a significantly lower specificity using blood compared to the other two kits (P = 0.004 compared to Witness, P = 0.007 compared to Anigen Rapid). False-positive test results occurred with all three kits using blood, and although using any two kits in parallel increased specificity, no combination of kits completely eliminated the occurrence of false-positive results. We therefore recommend FeLV proviral PCR testing for any cat that tests positive with a PoC FeLV antigen kit, as well as for any cat that has been potentially exposed to FeLV but tests negative with a FeLV antigen kit, before final assignment of FeLV status can be made with confidence. For saliva testing, sensitivity and specificity was 54% and 100%, respectively, for all three test kits. The reduced sensitivity of saliva testing compared to blood testing, although not statistically significant, suggests saliva testing with the current generation of PoC FeLV antigen kits is unsuitable for screening large populations of cats, such as in shelters.     

提升大学生科研创新潜质的考试方法改革研究

通过对东北林业大学课程考试方法的改革实践,旨在全面考查学生的课程学习效果,提升大学生科研创新潜质。认为注重课程全过程考核,实行多次累加式考试是大学生课程考试方法改革的趋势。     

设施韭菜全程机械化生产技术探索与推广

为切实提高设施韭菜各主要生产环节的机械化水平,通过引进田园管理机、蔬菜精密播种机以及韭菜收割机等,开展了设施韭菜全程机械化生产技术的示范与推广工作,摸索出设施韭菜全程机械化生产技术工艺路线,并为设施蔬菜的全程机械化生产提供参考。     

连续回转式甘蔗收割机集堆机构设计与试验

集堆是整秆式甘蔗收割机的重要作业工序之一,集堆性能影响到收割机作业质量。本文在分析现有的几种甘蔗收割机集堆机构的基础上,设计了一种连续回转式集堆机构,并试制了样机。田间试验结果表明,该机构能够有效实现甘蔗集堆功能,达到了设计要求。     

核桃乳-牛乳混合发酵酸奶的研制及成分分析

采用L9(34)正交试验对核桃乳-牛乳混合发酵酸奶进行了试验研究。试验结果表明,使用保加利亚乳杆菌(Lactobacillusbulgaricus)和嗜热链球菌(Streptococcusthermophilus)混合菌种按1∶1的比例,核桃乳∶牛乳为5∶5,在(40±1)℃下发酵5h,1～5℃冷却后熟12h,具有较好的效果。每100mL成品含蛋白质1 92g,脂肪2 03g,硫胺素1 12 ,核黄素1 9 ,磷0 32 ,铁0 19 ,黄酮1 76μg。成品口味清香,具有核桃特有的香味,口感细腻,色泽洁白。     

毛细管微萃取结合荧光光谱法快速测定全血中异丙酚含量的研究

[目的]建立在毛细管微反应器中快速萃取结合荧光光谱法测定全血中异丙酚含量的新方法。[方法]优化的条件为:5 ml环己烷为萃取剂,1 ml甲醇为沉淀剂,萃取3 min。[结果]在优化条件下异丙酚的平均萃取率大于99%,方法的线性范围为0.05~10.00μg/ml。日内相对标准偏差小于2%。[结论]毛细管微反应器萃取血样中异丙酚的方法方便、可行。     

低胰蛋白酶抑制剂全豆豆浆的研制

[目的]研制低胰蛋白酶抑制剂全豆豆浆.[方法]利用中性蛋白酶和复合超微粉碎技术制备低胰蛋白酶抑制剂全豆豆浆,创新性地在打浆时加入中性蛋白酶,并研究了打浆豆水比、打浆温度、蛋白酶添加量、酶解时间对豆浆水解度和胰蛋白酶抑制剂钝化率的影响,并利用正交试验进行了工艺优化.[结果]试验表明,豆水比1∶7、水解温度50℃、酶用量16 μl/g、酶解时间20 min可钝化90％以上的胰蛋白酶抑制剂.添加豆浆质量3％的β-环糊精可以掩蔽酶解后豆浆的苦味.[结论]研究可为低胰蛋白酶抑制剂全豆豆浆的工业化生产提供参考.     

全麦粉面筋指数法在小麦育种中应用条件的研究

[目的]为了更加灵活、方便地对小样本小麦品种进行品质测定,采用全麦粉面筋指数法代替面粉面筋指数法进行研究.[方法]选用适合山西省南部小麦种植的高、中、低筋型10个小麦品种(系)为试验材料,对不同温度、湿度条件下小麦全麦粉面筋指数(简称小麦面筋指数)与面粉的沉降值、稳定时间的相关性,小麦面筋指数与面粉面筋指数的相关性进行分析研究.[结果]通过试验可以得出,小麦面筋指数测定条件以温度20℃,湿度50％左右最适宜,且小麦面筋指数与面粉面筋指数高度相关,小麦湿面筋含量与面粉湿面筋含量高度相关,相关系数均在0.9以上.[结论]利用小麦面筋指数法可以代替面粉面筋指数法指导小麦育种、仓储及面粉和食品加工等.     

Changes of platelet function and blood coagulation during short-term storage of CPDA-1-stabilised ovine blood

The objective of this study was to detect the influence of short-term storage on the haemostatic function in whole citrated ovine blood at different storage temperatures. Ovine blood was collected in a commercial transfer bag system containing CPDA-1 and stored on a wobbler at room (20-25 °C; n = 5) or refrigerator temperature (4 °C; n = 5). The following analyses were performed initially and after 1, 2, 3, 4, 5, 6, 8, 12, 24, 48 and 72 h of storage: platelet count and (spontaneous) aggregates, agonist-induced platelet aggregation with two methods (impedance aggregometry, turbidimetric method), prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen concentration and resonance thrombography.Platelet count remained stable at room temperature, whereas a significant decrease was detected after 48 h storage at 4 °C. The latter was associated with the formation of a high percentage of platelet aggregates (50-60%) after 5 h storage. Decrease in platelet aggregation was significantly more pronounced when blood was stored at 4 °C. The plasmatic coagulation tests were stable within the observation period.Results indicate that platelet count and aggregability of CPDA-1-stabilised ovine blood is better preserved at room temperature and provides adequate haemostatic function for ex vivo experiments for one working day. Functional loss and high percentage of platelets within aggregates which were observed in ovine blood stored at refrigerator temperature have to be considered in blood transfusion in sheep.     

Combined effects of glucose oxidase,papain and xylanase on browning inhibition and characteristics of fresh whole wheat dough

In this study, a glucose oxidase (GOX), papain and xylanase combination was developed for fresh whole wheat dough for both browning inhibition and rheological improvement. Measurements of carotenoids extracted from enzyme-treated doughs showed that 0.001% (w/w) GOX could catalyze the oxidization of 40.0% carotenoids and thus cause a decrease of browning index (BI) by 5.20 during dough preparation. For 24 h browning inhibition, 0.010% (w/w) xylanase and papain individuals were able to separately act on the phenolic compounds and polyphenol oxidase, leading to lower BI rises (5.36 and 7.04, respectively) of doughs as compared to the BI rise (13.53) of the control dough; however, 0.020% GOX caused a higher BI rise (16.60) than control although it made BI decrease by 6.34 at 0 h. Rheological investigations on enzyme-treated doughs revealed that both xylanase and papain led to decreases of elastic (G′) and viscous modulus (G″) of doughs while GOX caused increases of G′ and G″. Therefore, an optimal combination composed of 0.010% (w/w) xylanase, 0.005% (w/w) papain and 0.002% (w/w) GOX was carried out using orthogonal experimental design by comparing BI rises in 24 h, which was also proved as a rheological improver for fresh whole wheat dough.