Crystallization and preliminary X-ray analysis of an anti-insect toxin BmK 16 fromButhus martensii Karsch scorpion

An excitatory anti-insect toxin from BmK scorpion, named BmK 16, has been purified and crystallized recently. Two crystal forms have been obtained by using ammonium sulfate as precipitant at different pH, one of which is single crystal. Diffraction data have been collected for the single crystal on a Mar Research 345 Image Plate. The analyses of the data show that the crystal can diffract to 0.28 nm resolution and belongs to the space group C2 with unit cell parameters a = 4.65 nm,b = 8.52 nm,c = 3.26 nm, α = γ = 90°, β = 110.5°. There are 2 molecules per asymmetric unit according to its unit cell volume and molecular weight.     

反舰导弹捕捉目标概率算法模型

讨论了反舰导弹末制导雷达捕捉目标的物理过程和条件,据此,采用统计理论,建立了反舰导弹末制导雷达对目标捕捉概率的数学模型;分析了与传统算法的差别和影响捕捉概率的参数,为工程技术人员提供了一套实用算法.     

虚拟现实引擎中的入口技术

入口是存在于小区中的一类特殊的多边形。由于入口算法简单高效,可以很容易实现室内场景的隐藏面消除。本文首先介绍了入口技术及其算法,然后给出了其在室内实时三维引擎中的具体应用,最后提出了若干改进方案。     

VR-GIS地质景观技术研究

虚拟现实地理信息系统(VR-GIS)是地理信息系统(GIS)技术的一个重要发展方向。虚拟景观技术是VR-GIS技术的研究热点之一。本文结合实际工程地质数据,研究了VR-GIS地质景观技术,包括基于空间散点数据的三维景观重建、基于图像处理的景观重建技术,以及景观虚拟漫游技术。     

Exome sequencing of gastric adenocarcinoma identifies recurrent somatic mutations in cell adhesion and chromatin remodeling genes

Gastric cancer is a major cause of global cancer mortality. We surveyed the spectrum of somatic alterations in gastric cancer by sequencing the exomes of 15 gastric adenocarcinomas and their matched normal DNAs. Frequently mutated genes in the adenocarcinomas included TP53 (11/15 tumors), PIK3CA (3/15) and ARID1A (3/15). Cell adhesion was the most enriched biological pathway among the frequently mutated genes. A prevalence screening confirmed mutations in FAT4, a cadherin family gene, in 5% of gastric cancers (6/110) and FAT4 genomic deletions in 4% (3/83) of gastric tumors. Frequent mutations in chromatin remodeling genes (ARID1A, MLL3 and MLL) also occurred in 47% of the gastric cancers. We detected ARID1A mutations in 8% of tumors (9/110), which were associated with concurrent PIK3CA mutations and microsatellite instability. In functional assays, we observed both FAT4 and ARID1A to exert tumor-suppressor activity. Somatic inactivation of FAT4 and ARID1A may thus be key tumorigenic events in a subset of gastric cancers.     

A novel member of the Rhomboid family, RHBDD1, regulates BIK-mediated apoptosis

Rhomboid family members are widely conserved and found in all three kingdoms of life. They are serine proteases and serve important regulatory functions. In the present study, a novel gene highly expressed in the testis, RHBDD1, is shown to be a new member of the Rhomboid family, participating in the cleavage of BIK, a proapoptotic member of the Bcl-2 family. The RHBDD1-involved proteolytic modification is upstream of the BIK protein degradation pathway. Mutagenesis studies show that the amino acid residues glycine142 and serine144 of RHBDD1 are crucial for its activity in cleaving BIK at a site located in the transmembrane region. Overexpression or knock-down of RHBDD1 in HEK 293T cells can reduce or enhance BIK-mediated apoptosis, respectively. The present findings suggest that, by acting as a serine protease, RHBDD1 modulates BIK-mediated apoptotic activity. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 31 July 2008; received after revision 16 September 2008; accepted 19 September 2008     

导弹武器系统效能评估方法研究

综合分析了目前使用的效能评估方法和模型 ,分析了它们使用范围和存在的问题 ,并针对导弹武器系统提出了一种新的评估方法———概率矩阵法。该方法克服了现有方法的局限性 ,它既可以评价某一具体战场环境下的效能 ,也可以综合评价导弹武器系统在某一类战场环境 (或某国的防御体系 )下的效能     

风屏障开孔形式对车桥系统气动特性影响的数值研究

随着高速铁路的发展,列车在横风作用下的安全问题尤为重要。采用流体力学软件Star CCM+建立32 m简支箱梁和CRH2型高速列车的全尺寸模型,对不同风屏障开孔形式的车桥系统进行数值模拟,研究了风屏障开孔形式对风屏障挡风效率和流场的影响,分析了车辆三分力系数和桥梁三分力系数随开孔形式的变化规律。结果表明：风屏障的开孔形式对车辆的阻力系数影响较大,且随着开孔边数的增加各车辆的阻力系数先减小后增大,开孔形式为格栅形时阻力系数最大。采用格栅形式时中车比头车的力矩系数大了63.6%;中车的阻力系数和力矩系数随开孔边数的增加基本呈下降趋势,位于背风侧时中车阻力系数和力矩系数变化较缓;随着风屏障开孔边数的增加,桥A段、桥B段和桥C段的阻力贡献率CR_WBD都呈增加趋势,其中桥B段的贡献率增加最多,增加了12.2%。风屏障对阻力和力矩的贡献率CR_WBD、力矩贡献率CR_WBM基本都超过了50%。     

生物质电厂灰渣建材化应用

为解决生物质电厂灰渣堆存量大,利用率低、利用过程二次污染严重等问题,首先,通过利用X射线衍射(X-ray diffraction, XRD)、X射线荧光(X-ray fluorescence, XRF)、热重-微分热重(thermal gravity-differential thermogravimetry, TG-DTG)、pH、粒度分析等常规分析方法对生物质电厂灰渣的理化特性进行了分析;其次,对比分析了生物质电厂灰渣建材资源化利用的方式和方法;最后,基于生命周期理论对生物质电厂灰渣建材资源化利用的环境效益和经济效益进行了分析。结果表明：生物质电厂灰渣富含SiO₂、Al₂O₃和Fe₂O₃等矿物,具有良好的火山灰活性,可直接进行建材资源化利用;目前生物质电厂灰渣的建材资源化主要利用方式是建材掺合料,陶瓷、黏土砖添加剂和路基填充材料;环境和经济评估结果表明生物质电厂灰渣的建材资源化利用不仅可实现灰渣的大规模、无害化利用,还具有良好环境和经济效益。虽然生物质电厂灰渣的建材资源化利...     

拆分降尺度卷积神经网络入侵检测方法

针对卷积神经网络(convolutional neural network, CNN)模型待训参数量过大、多层网络导致特征和梯度消失等问题,提出一种基于拆分层和Inception-ResNet的卷积神经网络模型用于入侵检测。首先将网络流量数据转化为具有空间相关性的图像以适用于卷积神经网络的输入;然后使用Inception-ResNet卷积层增加网络深度,减少模型训练参数数量以及消除梯度消失问题,拆分层在降低图像尺度时基本保持图像原有分类特征;最后采用NSL-KDD数据集对改进模型进行训练和测试。测试结果表明：改进模型相对于Inception-ResNet模型具有更高的检测准确率和少数类样本召回率以及更好的训练时间性能。