Regulation of the Edwardsiella tarda Hemolysin Gene and luxS by EthR

Edwardsiella tarda is a pathogen with a broad host range that includes human and animals. The E. tarda hemolysin (Eth) system, which comprises EthA and EthB, is a noted virulence element that is widely distributed in pathogenic isolates of E. tarda. Previous study has shown that the expression of ethB is regulated by iron, which suggests the possibility that the ferric uptake regulator (Fur) is involved in the regulation of ethB. The work presented in this report supports the previous findings and demonstrates that ethB expression was decreased under conditions when the E. tarda Fur (Fur(Et)) was overproduced, and enhanced when Fur(Et) was inactivated. We also identified a second ethB regulator, EthR, which is a transcription regulator of the GntR family. EthR represses ethB expression by direct interaction with the ethB promoter region. In addition to ethB, EthR also modulates, but positively, luxS expression and AI-2 production by binding to the luxS promoter region. The expression of ethR itself is subject to negative autoregulation; interference with this regulation by overexpressing ethR during the process of infection caused (i) drastic changes in ethB and luxS expressions, (ii) vitiation in the tissue dissemination and survival ability of the bacterium, and (iii) significant attenuation of the overall bacterial virulence. These results not only provide new insights into the regulation mechanisms of the Eth hemolysin and LuxS/AI-2 quorum sensing systems but also highlight the importance of these systems in bacterial virulence.

青海地区唐古特大黄药材HPLC指纹图谱研究

目的建立了青海地区唐古特大黄药材的HPLC指纹图谱.方法采用反相高效液相色谱法,乙腈-水（0.04%的磷酸）为流动相,梯度洗脱,体积流量1.0 mL/min,检测波长为280 nm,柱温为40 C.结果精密度、重现性、稳定性试验中共有峰面积和保留时间的RSD均小于5%.青海不同采集地唐古特大黄的平均相似度为0.925.结论该方法简便、实用、可靠,可用于以青海果洛地区为主产地不同海拔唐古特大黄药材质量标准的分析检测,也为栽培大黄代替野生大黄提供理论基础.

应用RAPD标记研究不同生态区谷子品种的遗传差异

应用RAPD标记对19份国内不同生态区的谷子品种的遗传变异进行了研究。结果表明：分子水平上，不同生态区的谷子品种存在一定的遗传差异，但遗传差异程度并不高。11个随机引物共扩增出54条多态性带，不同引物扩增的带数差异较大，每个引物可扩增2～8条多态性带，平均每个引物扩增出4.91条多态性带。引物1050扩增的多态性带最多（8条）。聚类结果表明，基于RAPD标记分析的遗传聚类群与生态类型有很大的一致性。

两种雀形目鸟类的窝雏数处理实验：检验Lack假说

于1997—1999年在位于青海省北部的中国科学院海北高寒草甸生态系统定位站进行。选择地面筑巢的小云雀(Alauda gulgula)和灌丛筑巢的黄嘴朱顶雀(Acanthis flavirostris)为代表进行窝雏数处理实验。根据Lack假说的预报检验(1)常见窝卵数是否是最大生产力窝卵数；(2)窝雏数处理对雏鸟质量和亲鸟投入是否产生影响；(3)两种鸟的响应方式是否相同。其结果如下：①小云雀和黄嘴朱顶雀的常见窝卵数分别是3和5枚。年间变化不明显，用幼鸟出飞率作为生产力，两种鸟的扩增窝幼鸟出飞率下降，常见窝卵数(分布频率最高)等同于最大生产力窝卵数；②小云雀的幼鸟的生长参数不随窝雏数的改变而变化．而黄嘴朱顶雀有明显变化．说明窝雏数处理对后者幼鸟质量有明显影响。③用递食率作为亲鸟投资指标，小云雀亲鸟的递食率随窝雏数的增加而增加，但雏期不变；而黄嘴朱顶雀递食率不变，但雏期延长。④扩增窝雏数后，两种亲鸟表现出不同的响应方式，小云雀表现为提高单位时间递食次数，而黄嘴朱顶雀延长育幼时间。这两种方式不是通过影响雏鸟质量就是通过影响亲鸟存活率来降低子代和亲代的适合度。结果支持了自然选择将窝卵数调节到亲鸟能喂活最大数量子代的限度。即常见窝卵数就是最大生产力窝卵数的Lack假说。

移动机械手协调的研究进展

移动机械手的协调是结合操作能力和移动能力的典范。本文针对目前已有的典型协调策略做出了论述，指出各自的优点和不足，精确总结了协调的要素和研究的方向。

自治式移动车视觉导航系统：道路寻找及障碍检出方法的研究

自治式移动车系统中的一个主要课题是视觉导航系统的研制。本文介绍了作者有关自治式移动车视觉系统的研究工作和实验结果，对道路分割及障碍检出的问题及方法，从理论与实验的角度予以剖析，提出了一些解决问题的新方法，同时根据实验中存在一些问题，对进一步的工作提出了有益的设想。论文工作包括如下四部分：1 一般道路的基于彩色的区域分割方法。2 消失点-路边支持道路分割方法3 基于道路区域宽度直方图分析的道路形状识别方法4 大间距垂直上下双相机立体障碍物检出方法

地球化学勘查综合方法在潞西金矿找矿中的应用

地球化学勘查是找矿预测的重要手段，在云南潞西金矿的地质勘查工作中采用了多种地球化学勘查手段，包括X荧光、γ能谱、氨气测量及地电化学。X荧光测量能快速有效地对成矿有利地段的红色粘土层进行快速评价，圈定矿化带和红色粘土型金矿体；在有红色粘土型金矿矿化异常的地段，采用简便易行的γ能谱和氡气测量进行初查，再进一步开展地电化学勘查工作寻找卡林型原生金矿。多种方法综合运用，取得了良好的找矿效果。

Our missions in India 1834-1924 , by Rev. E.M. Wherry.

http://www.archive.org/details/ourmissionsinind012419mbp

Disciplined Seeing: Forms of Christianity and Forms of Life

Estrategias en la resolución de problemas matemáticos de la prueba pisa. Un estudio de casos

El artículo analiza las estrategias desarrolladas por estudiantes de nivel medio superior al resolver problemas matemáticos de la prueba PISA. El estudio toma como base las explicaciones escritas, verbales y gestuales presentadas por los estudiantes en el proceso de resolución de los problemas. Fueron caracterizadas dos tipos de estrategias: formales e informales. Las primeras, a partir de conceptos sobre objetos, relaciones y operaciones, así como de proposiciones y propiedades matemáticas y las segundas, por medio de transformaciones como la descomposición y recomposición de formas geométricas, asimismo, del uso de la estimación visual y estimación de medidas.

La práctica de la simulación en la solución de problemas de probabilidad: el caso de los estudiantes del nivel medio superior

En este trabajo en proceso presentamos los resultados de la primera fase de nuestra investigación (análisis preliminar), que pretende reconocer a la práctica o la estrategia de la simulación que realizan los estudiantes al momento de resolver problemas de probabilidad y con ello las cuestiones en probabilidad será de gran sencillez teniendo a la herramienta de la simulación. En ello sostenemos que la práctica de la simulación enriquece al conocimiento matemático del ser humano y en particular a la probabilidad.

Triterpenoid saponins from a cytotoxic root extract of Sideroxylon foetidissimum subsp. gaumeri

Evaluation of the cytotoxicity of an ethanolic root extract of Sideroxylonfoetidissimum subsp. gaumeri (Sapotaceae) revealed activity against the murine macrophage-like cell line RAW 264.7. Systematic bioassay-guided fractionation of this extract gave an active saponin-containing fraction from which four saponins were isolated. Use of 1D ((1)H, (13)C, DEPT135) and 2D (COSY, TOCSY, HSQC, and HMBC) NMR, mass spectrometry and sugar analysis gave their structures as 3-O-(beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl)-28-O-(alpha-L-rhamnopyranosyl-(1-->3)[beta-D-xylopyranosyl-(1-->4)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl)-16alpha-hydroxyprotobassic acid, 3-O-beta-D-glucopyranosyl-28-O-(alpha-L-rhamnopyranosyl-(1-->3)[beta-D-xylopyranosyl-(1-->4)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl)-16alpha-hydroxyprotobassic acid, 3-O-(beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl)-28-O-(alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)[beta-D-apiofuranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl)-16alpha-hydroxyprotobassic acid, and the known compound, 3-O-beta-D-glucopyranosyl-28-O-(alpha-L-rhamnopyranosyl-(1-->3)[beta-D-xylopyranosyl-(1-->4)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl)-protobassic acid. Two further saponins were obtained from the same fraction, but as a 5:4 mixture comprising 3-O-(beta-D-glucopyranosyl)-28-O-(alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)[beta-D-apiofuranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl)-16alpha-hydroxyprotobassic acid and 3-O-(beta-D-apiofuranosyl-(1-->3)-beta-D-glucopyranosyl)-28-O-(alpha-L-rhamnopyranosyl-(1-->3)[beta-D-xylopyranosyl-(1-->4)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl)-16alpha-hydroxyprotobassic acid, respectively. This showed greater cytotoxicity (IC(50)=11.9+/-1.5 microg/ml) towards RAW 264.7 cells than the original extract (IC(50)=39.5+/-4.1 microg/ml), and the saponin-containing fraction derived from it (IC(50)=33.7+/-6.2 microg/ml).

Inclusion of poorly soluble drugs in highly ordered mesoporous silica nanoparticles

Silica nanoparticles (MSNs) with a highly ordered mesoporous structures (103A) with cubic Im3 m have been synthesized using triblock copolymers with high poly(alkylene oxide) (EO) segments in acid media. The produced nanoparticles displayed large specific surface area (approximately 765 cm(2)/g) with an average particles size of 120 nm. The loading efficiency was assessed by incorporating three major antiepileptic active substances via passive loading and it was found to varying from 17 to 25%. The state of the adsorbed active agents was further analyzed using differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). Dissolution studies revealed rapid release profiles within the first 3 h. The viability of 3T3 endothelial cells was not affected in the presence of MSNs indicating negligible cytotoxicity. 2009 Elsevier B.V. All rights reserved.