泡利酚对缺铁性贫血成龄大鼠脾脏铁,铜,锌含量的影响

从微量元素角度对脾脏微量元素铁,铜,锌含量进行了研究,探讨了泡利酚对缺铁性贫血成龄大鼠免疫功能的影响。用Ｗｉｓｔａｒ大鼠,随机分为正常对照组及缺铁性贫血模型组。     

叶绿素荧光成像技术的葡萄霜霉病早期检测

葡萄霜霉病对葡萄生产构成严重威胁,尽早防治是治理霜霉病的关键.为了对该病进行早期检测,以PCR检测获取的霜霉病相对生物量作为霜霉病侵染的依据,从暗适应—光适应—暗弛豫3个光合生理状态连续变化过程中,采集80个人工接种霜霉菌叶片和80个健康对照叶片连续6 d的叶绿素荧光图像.对比健康和接种叶片叶绿素荧光动力学曲线、参数图...     

经股动脉途径射频消融术建立beagle犬永久性房室传导阻滞模型

目的探讨经股动脉途径射频消融术建立beagle犬永久性房室传导阻滞模型的可行性,并比较其与传统造模方法的利弊.方法将12只beagle犬分成两组,预置起搏器后,左心室消融组(6只)经股动脉途径于主动脉窦下左心室间隔上部消融建立房室传导阻滞模型,右心室消融组(6只)经股静脉途径于koch三角处消融建立房室传导阻滞模型.两组以建立完全房室传导阻滞为终点.术后随访4周后处死动物,比较造模成功率、手术并发症及模型稳定性.结果左心室消融组成功率大于右心室消融组,术中并发症小于右心室消融组,左心室消融组手术时间及X线曝光时间短于右心室消融组(均P<0.05),两组模型稳定性差异无统计学意义(均P>0.05).结论经股动脉途径射频消融术建立beagle犬永久性房室传导阻滞模型较传统途径消融法成功率高且并发症少,在有条件的实验室和有经验的单位,可优先选用经股动脉射频消融术建立房室传导阻滞模型.     

SPEW: Synthetic Populations and Ecosystems of the World

Agent-based models (ABMs) simulate interactions between autonomous agents in constrained environments over time and are often used for modeling the spread of infectious diseases. ABMs use information about agents and their environments as input, together referred to as a “synthetic ecosystem.” Previous approaches for generating synthetic ecosystems have some limitations: they are not open-source, cannot be adapted to new or updated input data sources, or do not allow for alternative methods for sampling agent characteristics and locations. We introduce a general framework for generating synthetic ecosystems, called “Synthetic Populations and Ecosystems of the World” (SPEW). SPEW lets researchers choose from a variety of sampling methods for agent characteristics and locations and is implemented as an open-source R package. We analyze the accuracy and computational efficiency of SPEW, given different sampling methods for agent characteristics and locations, and provide a suite of statistical and graphical tools to screen our generated ecosystems. SPEW has generated over five billion human agents across approximately 100,000 geographic regions in over 70 countries available online.     

Disease dynamics in a dynamic social network

We develop a framework for simulating a realistic, evolving social network (a city) into which a disease is introduced. We compare our results to prevaccine era measles data for England and Wales, and find that they capture the quantitative and qualitative features of epidemics in populations spanning two orders of magnitude. Our results provide unique insight into how and why the social topology of the contact network influences the propagation of the disease through the population. We argue that network simulation is suitable for concurrently probing contact network dynamics and disease dynamics in ways that prior modeling approaches cannot and it can be extended to the study of less well-documented diseases.     

Hierarchical closeness efficiently predicts disease genes in a directed signaling network

BackgroundMany structural centrality measures were proposed to predict putative disease genes on biological networks. Closeness is one of the best-known structural centrality measures, and its effectiveness for disease gene prediction on undirected biological networks has been frequently reported. However, it is not clear whether closeness is effective for disease gene prediction on directed biological networks such as signaling networks.ResultsIn this paper, we first show that closeness does not significantly outperform other well-known centrality measures such as Degree, Betweenness, and PageRank for disease gene prediction on a human signaling network. In addition, we observed that prediction accuracy by the closeness measure was worse than that by a reachability measure, but closeness could efficiently predict disease genes among a set of genes with the same reachability value. Based on this observation, we devised a novel structural measure, hierarchical closeness, by combining reachability and closeness such that all genes are first ranked by the degree of reachability and then the tied genes are further ranked by closeness. We discovered that hierarchical closeness outperforms other structural centrality measures in disease gene prediction. We also found that the set of highly ranked genes in terms of hierarchical closeness is clearly different from that of hub genes with high connectivity. More interestingly, these findings were consistently reproduced in a random Boolean network model. Finally, we found that genes with relatively high hierarchical closeness are significantly likely to encode proteins in the extracellular matrix and receptor proteins in a human signaling network, supporting the fact that half of all modern medicinal drugs target receptor-encoding genes.ConclusionTaken together, hierarchical closeness proposed in this study is a novel structural measure to efficiently predict putative disease genes in a directed signaling network.     

Qualitative analysis for a ratio-dependent predator-prey model with disease and diffusion

This paper is purported to study a reaction diffusion system arising from a ratio-dependent predator-prey model with disease. We study the dynamical behavior of the predator-prey system. The conditions for the permanent and existence of steady states and their stability are established. We can obtain the bounds for positive steady state of the corresponding elliptic system. The non-existence results of non-constant positive solutions are derived.     

Indoor radon and lung cancer: a case-control study

Lung-cancer risk to the general population from indoor radon remains controversial, although studies of radon exposure have established that radon decay products have been a cause of lung cancer among miners.

For the case group of patients, suffering from lung cancer, and the control group distributions of the number of homes with high indoor levels of radon were compared with the log-normal distribution, the empirical frequency distribution of the control group obeyed the theoretical log-normal distribution.

Using the ratio of frequencies of the case group to the control groups, or the relative frequencies, an association between the relative frequencies and indoor radon concentrations was found, and a positive correlation coefficient was obtained, thus enabling the rate of lung cancer to be estimated for certain indoor radon concentrations.

The significant difference between the mean radon levels for the case sample and the control led to the conclusion that patients with lung cancer lived in homes with radon concentrations which were significantly higher than those of Osijek’s inhabitants for the control sample.     

黄萎病棉叶光谱识别影响因素分析

通过开展光谱测试试验,对黄萎病棉叶光谱测试影响因素进行准确性分析,明确各因素对黄萎病棉叶光谱识别的影响程度,优化其光谱测试方法。结果表明:黄萎病不同严重程度下,棉叶病症部位反射率形状和大小在所有波段均高于正常部位,差异显著;白板做底板时棉叶光谱值在可见光波段略高于黑板,其他波段显著高于黑板;棉叶主茎叶影响较小,旁叶影响较大;相同或相邻叶位影响较小,不同叶位影响较大;正常叶叶位影响较小,病害叶叶位影响较大;棉叶背面光谱反射率在可见光波段高于正面,近红外波段呈先高后平再低的趋势,短波红外波段呈先高后低的趋势;不同测试时间,测试品种的棉叶光谱特征差异较小,单一条件下对病害识别的影响在可接受范围内;不同测试试验区的棉叶光谱特征差异很小,对病害识别基本无影响。各因素对黄萎病棉叶光谱识别的影响程度不同,结果可为作物病害光谱识别的研究人员提供参考。