浅析土生空团菌(Cenococcum geophilum)自然侵染率及其与植被、根际土壤因子的关系

为了明确土生空团菌环境适应机理,以内蒙古地带性植被为研究对象,调查和测定了不同森林类型区土生空团菌自然侵染率、植被类型、土壤养分含量变化,探讨土生空团菌自然侵染率与植被、土壤因子的关系。结果表明,从植被类型来看,大兴安岭兴安落叶松、黑里河油松、大青山虎榛子、乌拉山白桦、贺兰山青海云杉等宿主植物土生空团菌自然侵染率均为30%以上,不同森林类型区油松土生空团菌自然侵染率也存在一定的差异。从根际土壤因子分析,土生空团菌自然侵染率与根际土壤有机质(r=0.492)、全氮(r=0.479)呈明显正相关(P<0.05),与根际土壤速效磷(r=0.575)呈极显著正相关(P<0.01)。     

不同加热温度对兔肉肉质的影响

试验选择65、75、85、95℃4个加热梯度,一个未加热组作为对照,考察兔肉不同加热温度蒸煮损失、肉色、pH值及剪切力的变化情况。试验结果表明随温度升高蒸煮损失显著上升,pH值呈上升趋势但不同温度加热样品之间差异不显著;加热样品肉色与对照样品肉色差异显著,但是各加热组之间的肉色差异不大;剪切力有增大趋势,75℃加热组与85℃加热组差异不显著,其他各组均有明显差异。结论是,兔肉在加热温度不断升高的过程中,肉品质逐渐下降,不同的加热温度明显地对兔肉品质产生不同程度的影响。     

Crystal structure of a lipid G protein-coupled receptor

The lyso-phospholipid sphingosine 1-phosphate modulates lymphocyte trafficking, endothelial development and integrity, heart rate, and vascular tone and maturation by activating G protein-coupled sphingosine 1-phosphate receptors. Here, we present the crystal structure of the sphingosine 1-phosphate receptor 1 fused to T4-lysozyme (S1P(1)-T4L) in complex with an antagonist sphingolipid mimic. Extracellular access to the binding pocket is occluded by the amino terminus and extracellular loops of the receptor. Access is gained by ligands entering laterally between helices I and VII within the transmembrane region of the receptor. This structure, along with mutagenesis, agonist structure-activity relationship data, and modeling, provides a detailed view of the molecular recognition and requirement for hydrophobic volume that activates S1P(1), resulting in the modulation of immune and stromal cell responses.     

农民关于基本农田保护及规划管制风险的认知研究

利用武汉市主要基本农田保护区江夏区161份农户的调查问卷,从农户视角分析现有制度存在的缺陷.结果表明,农户作为基本农田保护的直接和主要参与者,其对基本农田保护相关知识的了解相当匮乏,对于基本农田保护的意愿也并不明显,因此基本农田保护的执行浮于政策.解决这一问题的方法是在基层加大基本农田保护相关知识的宣传力度和时效、制定合理的经济补偿制度、充分调动农户实施基本农田保护的积极性.     

大豆叶黄素的研究进展

叶黄素是对人类健康起着积极作用的功能因子,在保健食品等领域的前景十分广阔,目前已成为功能性食品成分研究中的热点。介绍了大豆叶黄素的结构与功能、检测方法、合成途径和关键基因以及遗传特性和影响因素等方面的研究进展。     

改进分量法的麦穗图像灰度—二值化处理

单位面积麦穗数是小麦产量预测中的一个重要参数,应用图像处理技术识别出麦穗的个数是测产的关键.本文提出改进G分量法,对图像上麦穗像素点的绿色分量值进行增强,然后灰度—二值化处理,使麦穗从背景中分隔开,并与普通分量法、最大值法和加权平均法处理后的图像进行了比较.随机选取50幅麦穗图像样本,分别使用上述几种方法处理,改进分量法比其他3种方法耗时分别降低了51.29％、70.68％和61.01％,同时后续的中值滤波用时也至少降低了11.45％.实验结果表明,改进分量法是有效的.     

Modeling and simulation of the upper limb artery system using three section electric network model

A three section electric network model is built for human upper limb arterial system according to the Windkessel model. Blood pressure waveform of brachial artery is inputted into the electric network model. The state space equations of the electric network model are refined by using the state space analysis and solved numerically by the fourth order Runge Kutta method to obtain the blood pressure and flow waveform of radial artery. Effects of changes of the electric network model’s parameters on the blood pressure and flow waveform are also analyzed in normal and different pathological conditions(arteriosc lerosis and hypertension). The results of simulation show that the parameters of the model can well reflect the physiological significations of the upper limb arterial system; the analytic and computational methods are of fairly high precision and fast convergence for the model; and the model can simulate effectively the hemodynamic characteristics of upper limb arteries under normal and different pathological conditions.     

德宏州小粒种咖啡园施肥经验总结

分析了对目前德宏州小粒种咖啡生产中实际存在的施肥问题,在前期施肥工作的基础上,结合当地土壤、气候和咖啡生长及需肥特点,总结出"改、培、平、巧"的具体施肥经验,以期提高咖啡生产效益,实现持续高产稳产和优质。     

Functional analysis and induction of four novel goose (Anser cygnoides) avian β-defensins in response to salmonella enteritidis infection

In the current study, four novel avian β-defensins (AvBDs) (AvBD2, 5, 9, and 10) were identified in tissues from the Chinese goose (Anser cygnoides). The antibacterial activity of the AvBDs showed that all of these AvBDs exhibited antibacterial activity against most of the bacteria investigated (P<0.01). In addition, antibacterial activity of all of the AvBDs against Staphylococcus aureus and Pasteurella multocida decreased significantly or was completely abolished at 150mM NaCl (P<0.01). None of the AvBDs showed hemolytic activity. AvBD2 and AvBD10 were expressed widely, whereas AvBD5 and AvBD9 mRNAs were expressed in a limited number of geese tissues. AvBD9 was significantly induced in some immune tissues from geese after Salmonella enteritidis infection. The others were significantly upregulated in small intestine and some immune tissues of the geese (P<0.01). The present results suggest that the AvBDs are part of the host defense mechanism of the goose.