贝类派琴虫和折光马尔太虫二重PCR方法的建立

根据基因库中派琴虫和折光马尔太虫的基因序列,分别设计了二对特异性引物,通过对二重PCR扩增条件的优化,研究建立了可同时检测鉴别这二种原虫的多重PCR。该技术对同一样品中的派琴虫和折光马尔太虫模板进行扩增,结果均同时得到2条大小与实验设计相符的596bp(派琴虫)和478bp(折光马尔太虫)的特异性扩增带,而对单孢子虫、嗜水气单胞菌、荧光假单胞菌、副溶血弧菌、溶藻弧菌、河弧菌和拟态弧菌等病原体的扩增,结果全为阴性。敏感性试验结果表明,该技术最低能检测到10pg的派琴虫和折光马尔太虫DNA。用该二重PCR对广西沿海的119份牡蛎样品进行检测,结果派琴虫和折光马尔太虫的阳性率分别为9.24%和1.68%,提示了中国南方沿海的养殖贝类中存在派琴虫和折光马尔太虫的感染。     

后干燥处理对防腐木材性能的影响初步研究

试验初步研究了后干燥处理对加铬砷酸铜(CCA-C)、季铵铜(ACQ-C和ACQ-D)三种防腐处理木材中铜的流失影响。结果表明:随着流失次数的增加,CCA-C、ACQ-C、ACQ-D三种防腐处理木材的铜流失量都呈降低趋势,最终降至非常低。随着处理温度的升高,3种防腐材的铜流失量都有所增大。CCA-C型木材防腐剂的抗流失性优于ACQ型木材防腐剂。在同等条件下,ACQ-D防腐材的铜流失率高于ACQ-C防腐材。     

Sperm penetration assay as an indicator of bull fertility

To predict the fertility of frozen-thawed bull spermatozoa, a sperm penetration assay (SPA) using zona-free hamster oocytes was optimized, and the assay results were compared with data from field fertility expressed as the non-return rate (NRR). To increase sperm penetration, the spermatozoa were pre-incubated and coincubated with oocytes in media containing various concentrations of heparin (0 to 50 μg/ml). Coincubation with 10 μg/ml heparin showed the highest sperm penetration (P<0.05); it is considered to be the optimized SPA method. Sperm fertility index values obtained from WSPA were significantly correlated with the historic average NRR of 46 bulls (P<0.01). To determine the normal range for SPA, we established the lower limits of the sperm fertility index and set the cut-off value at 2.55, at which point the NRR was more than 70%, using the receiver operating characteristic curve. The overall accuracy for the 46 bulls was 95.7% (44/46) for both the low and high NRR, with a sensitivity of 95.5% (21/22) and a specificity of 95.8%. This protocol would make it easier to discriminate bulls according to their sperm fertilizing ability.     

常温下1-MCP对番茄生理生化的影响

采用浓度为0.5μL·L-1和0.9μL·L-1的1-MCP对番茄进行处理,研究其对常温下番茄生理生化的影响。结果表明,1-MCP降低了番茄的呼吸强度,保持了果实的VC和可滴定酸的含量,延缓了果实可溶固形物含量的降低,提高了CAT活性,降低了PPO活性。采用浓度为0.9μL·L-1的1-MCP处理番茄保鲜效果较好。     

Identification of tumour initiating cells in feline head and neck squamous cell carcinoma and evidence for gefitinib induced epithelial to mesenchymal transition

Feline oral squamous cell carcinoma is considered a highly invasive cancer that carries a high level of morbidity. Despite aggressive surgery, patients often succumb to disease, the tumour having inherent insensitivity to radiation and chemotherapy. In this study we sought to identify cells within the feline SCC1 line that have stem cell properties, including inherent resistance mechanisms. When feline cells were subjected to harsh growth conditions, they formed sphere colonies consistent with a stem cell phenotype. Utilising CD133, we were able to identify a small fraction of cells within the population that had enhanced sphere-forming ability, reduced sensitivity to radiation and conventional chemotherapy and demonstrated resistance to the EGFR-targeting drug, gefitinib. In addition, long-term culture of feline SSC1 cells in gefitinib caused a change in cell morphology and gene expression reminiscent of an epithelial to mesenchymal transition. Taken together, these results suggest that feline SCC may be driven by small subset of cancer stem cells.     

樟子松枯梢病研究进展

从樟子松枯梢病病害的症状、病原菌、病菌生物学特性、寄主范围、侵染规律、流行规律和防治技术等7个方面综述了近年来樟子松枯梢病的研究进展。     

控制灌溉条件下寒区水稻茎秆抗倒伏力学评价及成因分析

为了评价控制灌溉处理与常规灌溉处理下水稻抗倒伏能力的差异,寻求有利于水稻茎秆抗倒伏的灌溉处理方式,以水稻茎秆为研究对象,研究了不同灌溉条件下水稻茎秆抗倒伏性能。引入茎秆系数,对水稻茎秆进行力学分析,比较了2种控制灌溉和常规灌溉3种水分处理下水稻茎秆抗倒伏能力的差异。结果表明,控制灌溉（KI、KII）处理下的水稻节间充实度高于常规灌溉（CK）,KI、KII处理的水稻茎秆壁厚分别比CK高出0.15 mm和0.35 mm;控制灌溉处理下的水稻茎秆系数显然低于常规灌溉处理,大小顺序为：CK＞KI＞KII;临界力的大小依次为：KII＞KI＞CK,因此控制灌溉处理的水稻茎秆更具抗倒伏性。     

河北省退耕还林对粮食生产的影响

从定性和定量角度分析退耕还林对粮食生产的影响,并采用灰色GM（1,1）模型预测河北省未来8年的人口发展趋势,最后利用灰色关联法对河北省粮食总产量的影响因素进行研究分析。结果表明：退耕还林造成全省耕地面积的减少,但由于其改善了粮食生产环境,大大提高了粮食单产,从而增加了粮食总产量;河北省未来人口持续增长,对耕地和粮食资源产生很大压力;在影响河北省粮食总产的诸因素中,粮食单产和灌溉是决定粮食总产的首要因素,而化肥施用量则为次要因素。     

基于MF-DFA特征和LS-SVM算法的刀具磨损状态识别

鉴于多重分形理论在精细刻画系统非线性现象和过程方面具有的独特优势,该文提出了基于多重分形去趋势波动分析和最小二乘支持向量机的刀具磨损状态识别方法。首先,用MF-DFA(multifractal detrended fluctuations analysis)方法处理去噪后的刀具磨损声发射信号,讨论其长程相关性和分形特性;然后,分析对比了不同磨损阶段下多重分形谱参数的变化,筛选出能灵敏表征刀具磨损状态的多重分形谱参数:分形维数最大值点对应的奇异指数α_0,多重分形谱谱宽△α和广义Hurst指数波动均值△h(q)作为特征量;最后,利用LS-SVM(least square support vector machine)算法并对比支持向量机和神经网络算法实现刀具磨损状态识别,结果表明LS-SVM算法识别率最高,平均识别准确率达97.78%,验证了本文所提方法的有效性。试验结果表明,提取的特征对刀具磨损状态的变化非常敏感,可以分离相近的磨损状态,为刀具状态监测提供一种参考方法。     

矿物质添加剂对玉米秸秆粉末催化热解特性的影响

依托自制生物质管式炉热解试验平台,以高速机械掺混的方式将添加剂与玉米秸秆粉末直接混合,在常速热解条件下探究不同添加剂(Na_2CO_3、CaO、Fe_2O_3)对玉米秸秆粉末的原位催化热解影响,分析计算试验数据得出:在玉米秸秆粉末热解过程中,3种添加剂均能不同程度降低液相产物产率,提高热解气中氢气产率,其中Na_2CO_3对液相产物的降低效果是CaO的1.5倍,Fe_2O_3的20倍,Na_2CO_3主要是催化促进热解气的产生,CaO则是促进焦炭的生成,并且二者的热解焦炭均有不同形式的结焦聚团,且CaO作用下的热解气低位热值较高,而Fe_2O_3对液相产物的降低效果较小;通过研究3种添加剂对玉米秸秆粉末的热解影响,为生物质催化热解中催化剂的选择和工矿企业废物利用提供了有价值的数据理论和方向。