纳豆芽孢杆菌固体发酵条件及其优化研究

为了优化纳豆芽孢杆菌固态发酵条件及确定适宜固态发酵培养基,以芽孢数为指标,采用固体发酵方法,研究了培养基组成、固液比、接种量、pH、培养基装量和发酵时间等发酵条件对芽孢数的影响,并通过响应面分析法确定了纳豆芽孢杆菌固态发酵的最佳发酵条件。结果表明：适宜的发酵条件为：麦麸58%、沸石粉34%、豆饼粉5.35%、葡萄糖2%、KH₂PO₄0.5%、MgSO₄?7H₂O0.15%、pH 7.56、固液比1:1.1、装量50.39g/250mL三角瓶、接种量4.16%、发酵时间4d。在此条件下,芽孢数达到6.48×10₁₀cfu/g。     

响应面法优化当归补血汤液体发酵工艺

为确定当归补血汤液体发酵的最佳工艺,本试验采用枯草芽孢杆菌为发酵菌种,以多糖提取率为评价指标进行液体发酵工艺优化。首先采用单因素试验考察发酵培养基中葡萄糖和蛋白胨添加量、菌液接种量和发酵时间对多糖提取率的影响,再以此为基础,采用Box-Behnken中心组合试验设计法,选取葡萄糖添加量、蛋白胨添加量、接种量、发酵时间为发酵优化的4个因素,以多糖提取率为响应值,设计4因素3水平的试验方案并进行响应面分析,以确定各因素与响应值多糖提取率的关系。结果显示,各因素对多糖提取率变化的贡献大小依次为葡萄糖添加量、蛋白胨添加量、接种量、发酵时间;利用响应面分析结果显示,蛋白胨添加量与接种量和发酵时间、接种量和发酵时间的交互作用较为显著,最终确定最佳发酵工艺条件为：葡萄糖添加量0.95%,蛋白胨添加量1.52%,接种量2.92%,发酵时间35.8 h。该条件下多糖提取率达到9.23%,与未发酵组（4.62%）相比,多糖含量提高近2倍。该工艺对液体发酵当归补血汤产多糖优化效果显著,为发酵当归补血汤的进一步开发利用提供了理论基础。     

天水市不透水表面提取及时空变化分析

不透水表面的发展是城市化进程的重要体现。采用天水市1996、2001、2007年3个时期的LandsatTM遥感影像,使用面向对象的方法,通过构建具有较强适应性的比值不透水表面指数RISI,结合植被指数NDVI、水体指数MNDWl等,从遥感影像中提取了不透水面信息,并对其时空发展变化和驱动力进行了分析。结果表明,天水市不透水表面增加明显,与该地区的自然地理格局和经济社会发展密切相关。     

基于Plackett-Burman试验设计与响应面法优化玉米秸秆离散元模型

为了减小免耕播种机防堵装置数值模拟的误差,结合物理试验与仿真试验进行玉米秸秆离散元参数的标定。基于Hertz-Mindlin with bonding 接触模型建立了玉米秸秆离散元模型,以物理试验与仿真试验中临界载荷的相对误差为试验指标进行仿真单轴压缩试验;采用Plackett-Burman试验筛选出具有显著性影响的试验因素;采用Box-Behnken响应面法对玉米秸秆离散元模型进行优化。试验结果表明:接触半径和单位面积切向刚度对试验指标影响极显著(P<0.01),单位面积法向刚度对试验指标影响显著(0.01<P<0.05);玉米秸秆的最优离散元参数为,接触半径1.2 mm、单位面积法向刚度9.361×10⁷ N/m³、单位面积切向刚度9.845×10⁷ N/m³,在此条件下,仿真压缩试验的临界载荷为950.2 N,与物理试验值935.4 N的相对误差为1.58%,验证了参数的可靠性。标定的玉米秸秆离散元模型可用于免耕播种机防堵装置的数值模拟,为防堵装置结构优化改进提供了依据。     

一种基于车身曲面重建的三角网格曲面参数化方法

三角网格曲面的参数化是车身曲面重建过程中的一个重要环节。三角网格曲面参数化是一个由3D到2D的可逆变换,可将对三角网格曲面的操作转化为对二维平面网格的操作,这样就大大地减小了应用操作的复杂性。在车身曲面重建的基础上研究了一种既保角又保面积的参数化方法,并判断其是否适应于车身曲面重建过程中的三角网格参数化。通过VC6.0编程结合UG软件为平台,应用车身实例来实现这种参数化方法的算法。     

环境影响评价工程分析中清洁生产思维的运用研究

根据环境影响评价和清洁生产各自的内容和特点,阐述了两者之间的内在联系,深入分析了两者之间最为重要的结合面一项目工程分析,并就建设项目环境影响评价工程分析中清洁生产思维的运用做了实用性探讨,同时也指出了两者结合面上的局限性,并提出了相应的解决方法和措施。     

不同林龄刺槐林对冀东铁尾矿客土土壤养分含量的影响

本研究选择唐山迁安马兰庄铁尾矿人工造林的3年生、5年生和12年生的刺槐林为研究对象,以未造林空地为对照,通过测定不同林龄林下土壤pH值、有机质、碱解氮、速效磷、速效钾、全磷、全钾、全氮含量,对比分析不同林龄刺槐对尾矿养分含量的影响,评价刺槐林对尾矿养分的改善效果。结果表明:(1)3个林龄地土壤pH差异不显著,均呈现弱酸性,土层越深,酸性越强。(2)不同林龄土壤有机质含量为:12年5年3年对照。(3)土壤全氮含量与有机质含量变化趋势相同,全磷、全钾含量变化为:3年5年12年对照;碱解氮含量变化与全氮含量变化相反,3年5年12年,且与对照相近或小于对照;而速效磷含量是对照空地最大,不同林龄未表现出明显的规律性;速效钾含量与全钾含量变化相同,对照3年5年12年。(4)不同林龄地养分含量普遍具有表聚性,随着土壤深度的增加呈现减少趋势。相关性分析结果表明,土壤深度对pH值、碱解氮和速效钾、有机质含量影响极显著或显著,而林龄仅对土壤全磷和速效磷含量有较显著影响(P0.01),对其他养分含量影响不显著。相比林龄,土壤深度对土壤酸碱性和养分含量的影响作用更大。     

密云水库水源涵养林对水质的影响

 为给密云水库流域的水质保护规划和控制措施提供理论依据,以密云县北庄镇为试验区对水源涵养林进行调查,对地表水进行监测,分析水质中存在的主要问题及其产生的原因。自2000年密云水库流域开始实施“退耕还林”工程以来,森林面积不断增加,减少了由于农田施肥造成的非点源污染,使地表水水质的浑浊度和氨氮指标有所下降。以油松林和板栗林为例,对降雨流经森林生态系统各环节的水质进行监测、分析,说明密云水库流域水源涵养林与降雨之间的淋溶、交换、吸附等过程对降雨具有净化作用。     

Outbreak of anaplasmosis associated with novel genetic variants of Anaplasma marginale in a dairy cattle

During early lactation, dairy cows may present a transient immunosuppressive state and develop anaplasmosis caused by Anaplasma marginale. In this study, clinical anaplasmosis in dairy cattle in the Thrace region of Turkey was investigated with respect to within-herd prevalence, vertical transmission, and genetic diversity. In March and September 2015, thirty lactating cows showed primary clinical signs of anaplasmosis, including fever, anaemia, decreased milk yield, anorexia, and laboured breathing. Symptoms disappeared in most cows after administration of long-acting oxytetracycline, but nine of them (30%) died. Following diagnosis based on clinical signs, microscopy and molecular findings, blood samples were collected from apparently healthy lactating cows (n = 184), pregnant heifers (n = 39) and newborn calves (n = 24). DNA was extracted from each sample and analyzed for the presence of major surface proteins (MSPs) of A. marginale, followed by sequencing to assess diversity of isolates. Microscopic examination of erythrocytes revealed A. marginale inclusion bodies in symptomatic cows. Examination of thin blood smears showed 3.8% of the lactating, clinically asymptomatic, cows to be infected with A. marginale, while nPCR detected 31.0% positive. A. marginale infection was not detected in pregnant heifers by either method. Congenital infection was found in one calf by nPCR. This is the first report of transplacental transmission of A. marginale in Turkey. The MSP4 sequence analyses showed high genetic diversity among the isolates, presenting 97.6-99.6% homology at the amino acid level. The sequences of MSP1a amplicons revealed genetic diversity providing three new tandem repeats.     

PET/CT today and tomorrow in veterinary cancer diagnosis and monitoring: fundamentals,early results and future perspectives

Functional imaging using positron emission tomography (PET) plays an important role in the diagnosis, staging, image‐guided treatment planning and monitoring of malignant diseases. PET imaging complements conventional anatomical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI). The strength of CT scanning lies in its high spatial resolution, allowing for anatomical characterization of disease. PET imaging, however, moves beyond anatomy and characterizes tissue based on functions such as metabolic rate. Combined PET/CT scanners were introduced commercially in 2001 and a number of technological advancements have since occurred. Radiolabelled tracers such as ¹⁸F‐fluorodeoxyglucose (FDG) and ¹⁸F‐fluorothymidine (FLT) allow visualization of various metabolic processes within cancer cells. Many studies in human oncology evaluating the utility of PET/CT have demonstrated clinical benefits. Few veterinary studies have been performed, but initial studies show promise for improved detection of malignancy, more thorough staging of canine cancer and determination of early response and disease recrudescence.