谱表达方法的频率取点优选

首先阐述了结构响应标准差谱的基本概念。以结构位移、速度和加速度稳态响应标准差谱误差最小为准则,阐明了对谱表达方法谐波分量频率进行优选的基本思想。在此基础上,提出了确定性频率和频率随机化两类频率优选方法。以Clough-Penzien谱为例,进行了数值实例分析。研究表明,当结构基本周期在0~3 s之间时,随机激励选取7个谐波分量即可,而对于基本周期在0~6 s的结构,随机激励含有50个谐波分量已经足够。这与经典谱表达方法中采用均匀频率取点时通常需要500~600个谐波分量相比,极大地降低了随机变量个数,有效地提高计算分析效率。

二维空间脉动风场波数-频率联合功率谱表达的FFT模拟

针对二维空间纵向脉动风场模拟问题,采用多维随机场理论,基于Davenport脉动风速谱和相干函数模型,导出了二维空间均匀脉动风场的波数-频率联合功率谱。通过谐波叠加直接获得二维空间均匀脉动风场,避免了经典谱表达方法在脉动风场模拟时的空间离散和互功率谱矩阵的Cholesky分解或本征正交分解(POD)。为了进一步提高风场模拟的效率,在数值程序中引入了快速Fourier变换(FFT)技术。最后,对风力机桨叶所在平面进行了二维空间脉动风场模拟,验证了该方法的准确性和高效性。

血管化复合同种异体移植物的免疫细胞亚群变化及基因谱表达

血管复合同种异体移植物(vascular composite allotransplant,VCA)可以对大面积组织缺损进行修复重建,但移植后存在着严重的免疫排斥问题,限制了其在临床上的广泛应用。VCA移植后外周血及移植物中免疫细胞亚群的变化及相关基因谱的表达,对于理解VCA排斥反应发生的免疫机制、寻找非侵袭性临床检查方法具有重要意义。

基于随机动力分析的高土石坝极限抗震能力研究

地震动的随机性对大坝的动力响应影响较大,极限抗震能力作为大坝抗震安全性能的重要环节,在评估过程中也应该充分考虑荷载随机性的影响。基于大量高土石坝随机动力有限元计算,探究坝顶震陷率和坝坡累计滑移量两个重要坝体变形指标之间的关系,并建议了土石坝安全控制标准。利用概率密度演化法对高土石坝进行极限抗震能力分析。结果表明:震陷率随着累计滑移量的增大而增大,二者之间符合逻辑斯蒂增长模型;取10%的超越概率,以250m规则高面板堆石坝和高心墙堆石坝为例,极限抗震能力分别为0.7g~0.75g和0.8g~0.85g;从概率角度提出了评估大坝极限抗震能力的新方法。

基于直接概率积分法的列车-轨道-桥梁系统随机分析

由于施工和制造误差使得铁路工程结构参数不可避免地具有不确定性,同时作为系统主要自激励的轨道不平顺亦具有明显的随机性和时变性,因此,探明不确定因子对列车和轨道-桥梁结构动态性能的影响非常重要。为了高效地完成列车-轨道-桥梁系统随机性能分析,建立列车-轨道-桥梁空间振动分析模型,采用轨道不平顺概率模型和谱表达-随机函数的方式在有限随机变量空间中实现轨道不平顺随机过程的高效模拟。引入概率密度积分方程和直接概率积分法发展了列车-轨道-桥梁系统随机动力方程和相应的计算求解策略。基于MATLAB实现了列车-轨道-桥梁随机振动的直接概率积分法分析程序,计算了全概率不平顺激励和参数随机条件下车-轨-桥系统振动响应的均值、标准差和时变的概率密度信息。研究结果表明:与概率密度演化分析方法相比,直接概率积分法可较好地反映行车过程中系统响应的概率密度特征,然而其在系统响应随机后处理时更为高效,其效率可提高1~2个数量级。此外,考虑轨道不平顺全概率激励更能准确地反映行车过程系统响应的概率特征,平均概率谱可能使得计算结果偏于保守;行车速度对于列车和桥梁动态行为的影响是显著的,随着行车速度的增加系统响应的范围逐渐变大。研究结果进一步拓展了列车-轨道-桥梁随机系统的分析方法,可以高效地用于系统状态评估和设计优化。

青蒿琥酯诱导人原代白血病细胞凋亡及其相关基因表达谱的初步研究

目的探索青蒿琥酯治疗人类急性白血病的作用及其分子机理。方法收集人类急性白血病患者骨髓细胞,进行原代培养;MTT法检测青蒿琥酯对急性白血病原代细胞增殖的影响;基因芯片观察青蒿琥酯作用前后相关基因表达变化。结果浓度为50,25,12.5μg/mL的青蒿琥酯分别作用于急性白血病原代细胞,48 h后抑制率依次为56.25%、41.49%、30.08%;72 h后抑制率依次为59.8%、45.07%、33.57%,呈剂量、时间依赖关系;青蒿琥酯对AL原代细胞的半数抑制率浓度(IC50)为18.3μg/mL;经青蒿琥酯作用后,AML-M3和ALL-L2原代细胞基因表达谱分别呈现变化趋势,并与药物剂量呈梯度比例关系。结论青蒿琥酯抗AL原代细胞的作用包括多方面,诱导细胞凋亡是其主要作用,可能的机制包括通过Bcl-2途径、线粒体途径、Tnf/TnfR1及Fas/FasL信号转导途径、Jak/Stat通路等诱导AL细胞凋亡;同时青蒿琥酯还有抑制AL原代细胞的增殖及诱导AL原代细胞向成熟分化的作用。

多向不规则波浪模拟的降维方法

基于多向不规则波的3种传统Monte Carlo模拟方法,提出了相应的时空随机场源谱表达,通过引入随机函数的降维思想,推导了3种多向不规则波模拟的降维方法,实现了仅用2个~4个基本随机变量即可精确表达多向不规则波随机场。数值算例表明,采用三种降维方法模拟所得代表性样本集的有效波高均符合规范要求。同时,代表性样本集的二阶统计量(模拟值)与目标值拟合一致,且总体上比传统Monte Carlo方法精度更高,验证了降维方法的有效性。此外,通过对比分析三种降维方法的模拟精度和效率,建议了最适用于工程应用的多向不规则波模拟方法,这为结合概率密度演化理论进行海洋工程结构在随机海浪作用下的动力可靠度精细化分析提供了有效途径。

半空间格林函数的角谱平面高效计算

将半空间并矢格林函数的索末菲积分用角谱平面积分表示 ,将原始的索末菲积分路径变换至最陡下降路径 ,针对场源位于不同区域时的分支割线和支点分布做了讨论 ,给出了最陡下降路径方程和相应的积分公式。对于可能涉及的支点奇异性 ,通过增加一条过支点的等相位路径来计算。角谱平面的计算方法有效地简化了SDP方程的推导与积分计算过程 ;

多变量随机过程的模拟方法研究

在对自然风或地震等随机过程的模拟中,具有随机振幅、频率含量和相位角的随机过程模拟模型能更加真实地反映其随机性。该文推导一种可以描述上述随机特性的单变量和多变量随机过程的模型,并从理论上证实所模拟的样本具有平稳性,各态历经性以及高斯性等统计特性。经过数值算例分析证明模型的准确性以及有效性。

基于波数-频率联合演变功率谱的一维空间非均匀脉动风场模拟

在高层建筑、大跨桥梁和大型风力发电系统等大型工程中,风荷载对结构的安全性至关重要、甚至是起控制作用的要素。因此,脉动风速场的模拟具有重要意义。谱表达方法得到了广泛的应用。但经典的谱表达方法需要对互功率谱矩阵的逐个频率点进行Cholesky分解或本征正交分解(POD),当模拟的空间点数较多时,分解效率非常低下、甚至可能出现矩阵奇异而难以实现。基于波数-频率联合功率谱或联合演变谱,不需要Cholesky分解或POD,可以方便地实现均匀或非均匀脉动风场的模拟。当模拟点为等间距点时,该方法能够使用FFT技术提高模拟效率,而当模拟点为非等间距点、不能使用FFT技术时,模拟效率依然有待提高。鉴于此,该文引入"结构化"非均匀离散方法和"舍选法"思想,建议了二维波数-频率域的非均匀离散策略,显著地提高了模拟效率。以某桥塔的一维空间非均匀脉动风场的数值模拟为例,验证了该方法的有效性。

南黄海西部2007年4月的逆温跃层

利用南黄海西部2007-04的温盐实测资料,采用海洋层结谱表达法及自适应识别,得到逆温跃层的"五点三要素",形成强度要素平面分布图。分析表明,逆温跃层的存在与黄海暖流水有直接的关系:1)4月份,黄海暖流水受到的海面冷却仍是产生逆温跃层的普遍原因,在该海区黄海暖流向北延伸和向两侧拓展的区域都有该种类型的逆温跃层存在,位置相对较浅;2)但在偏南的黄海暖流主干区,海面冷却产生的效应被主流区的热量补充所抵消,逆温跃层很弱甚至消失,这是该月份逆温跃层分布区向北退缩并在南部中心附近呈现缺失区的主要原因;3)南下的鲁北沿岸流水的冷水叠加在黄海暖流水的暖水上方,使逆温跃层加强,使得冷暖水的作用区成为强逆温跃层区;4)黄海暖流左侧冷沿岸流水及右侧冷水的前端向黄海暖流楔入,其前端往往覆盖在底层高温高盐的黄海暖流水上方形成下逆温跃层,从而形成双逆温跃层。这些特点,较以前认知更加客观、全面、细致和准确。

平稳随机脉动风场模拟的高维概率空间选点法

为进行结构抗风可靠度分析,需对作用在结构上平稳随机脉动风场进行模拟。采用谱表达法描述脉动风场往往涉及成千上万个随机变量,会造成“维数灾难”问题。基于此,本文提出一类高维概率空间选点法保障模拟的精度和效率,主要由3个步骤组成:高维概率空间的分解、正交子空间选点和随机配对得到高维概率空间离散代表点及赋得概率。采用本文的方法模拟了某30层框架剪力墙结构上沿高度变化的水平风场,研究表明:本文的方法在二阶统计意义上具有很高的模拟精度和效率,可用少量的代表性样本构建完备的概率集合,进一步结合概率密度演化法可对结构风振响应进行精细化概率评价。

Generation of Antibodies Against DMRT1 and DMRT4 of Oreochromis aurea and Analysis of Their Expression Profile in Oreochromis aurea Tissues

Sex determination is composed of somatic and germ-line sex differentiation hierarchies whose interaction is poorly understood. A single gene known to control somatic sex determination, the DM-domain containing （Doublesex/Mab-3 DNA-binding motif） gene, is highly conserved across species. Vertebrate DMRT1 （DM-related transcription factor 1） expression occurs predominantly in the testis. Here, however, isolated two distinct DM-domain cDNA from Oreochromis aurea ovary and testis have been named DMRT4 （DM-related transcription factor 4） and DMRT1 by BLAST, respectively. Despite high homology in the DM-domain there is little similarity outside the DM-domain.To better understand the structure, function, and possible roles of DMRT4 and DMRT1 as potential candidates for sex differentiation and sex determination, the intact regions encoding DMRT4 and DMRT1 obtained by PCR were sub-cloned into the vector pMAL-c2x and introduced into the Escherichia coli TB1 cell for efficient fusion expression. After purification and cleavage, DMRT4 and DMRT1 proteins were used to immunize adult rabbits following standard protocols. Consequently, it was found by using Western blot analysis that polyclonal antibodies against DMRT4 and DMRT1 had high specificity. The relative expression levels of DMRT4 and DMRT1 mRNA were determined by fluorescent Real-time RT-PCR in female and male Oreochromis aurea with 13-actin as the internal standard. DMRT1 was expressed only in testis, whereas DMRT4 was over expressed in the ovary, but in both female and male, a slight expression in the brain was also detected. Statistical analysis showed that in the brain, mean DMRT4 mRNA levels in female were significantly higher than in male. Meanwhile, the expression of DMRT4 and DMRT1 protein was also analyzed using the purified antibodies through Western blot and immunohistochemistry. It was found that DMRT4 was exclusively expressed in the ovary and DMRT1 in the testis. Study on DMRT4 and DMRT1 expression facilitated the elucidation of their roles and the understanding of sex differentiation of fish.

Hyperspectral image classification based on spatial and spectral features and sparse representation

To minimize the low classification accuracy and low utilization of spatial information in traditional hyperspectral image classification methods, we propose a new hyperspectral image classification method, which is based on the Gabor spatial texture features and nonparametric weighted spectral features, and the sparse representation classification method（Gabor–NWSF and SRC）, abbreviated GNWSF–SRC. The proposed（GNWSF–SRC） method first combines the Gabor spatial features and nonparametric weighted spectral features to describe the hyperspectral image, and then applies the sparse representation method. Finally, the classification is obtained by analyzing the reconstruction error. We use the proposed method to process two typical hyperspectral data sets with different percentages of training samples. Theoretical analysis and simulation demonstrate that the proposed method improves the classification accuracy and Kappa coefficient compared with traditional classification methods and achieves better classification performance.

随机波浪力连续场的降维模拟

根据水质点的水平速度和加速度过程的功率谱密度,利用线性化的Morison方程,从平稳随机过程自相关函数的角度推导了随机波浪力的功率谱密度函数。在平稳随机过程的源谱表达基础上,通过将标准正交随机变量集定义为仅含1个基本随机变量的正交函数形式,实现了随机波浪力连续场的降维模拟。同时,结合快速傅里叶变换(FFT)技术,给出了随机波浪力连续场降维模拟的快速算法。应用该方法对某一单个小尺度直立圆柱桩所受的随机波浪力进行模拟,给出了随机波浪力过程的均值、标准差、自相关函数及互相关函数等数值特征,并与Monte Carlo方法的结果进行对比分析。研究表明,降维模拟方法具有较高的模拟精度与效率。

Screening of the Metastasis-Associated Genes by Gene Chip in High Metastatic Human Ovarian Cancer Cell Lines

Affymetrix U133A oligonucleotide microarrays were used to study the differences of gene expressions between high （H） metastatic ovarian cancer cell line, HO-8910PM, and normal ovarian tissues （C）. Bioinformatics was used to identify their chromosomal localizations. A total of 1,237 genes were found to have a difference in expression levels more than eight times. Among them 597 were upregulated [Signal Log Ratio （SLR） ≥3], and 640 genes were downregulated （SLR≤-3）. Except one gene, whose location was unknown, all these genes were randomly distributed on all the chromosomes. However, chromosome 1 contained the most differentially expressed genes （115 genes, 9.3%）, followed by chromosome 2 （94 genes, 7.6%）, chromosome 12 （88 genes, 7.1%）, chromosome 11 （76 genes, 6.1%）, chromosomes X （71 genes, 5.7%）, and chromosomes l7 （69 genes, 5.6%）. These genes were localized on short-arm of chromosome （q）, which had 805 （65.1%） genes, and the short arms of No.13, 14, 15, 21, and 22 chromosomes were the only parts of the chromosomes where the differentially expressed genes were localized. Functional classification showed that most of the genes （306 genes, 24.7%） belonged to the enzymes and their regulator groups. The subsequent group was the nucleic acid binding genes （144 genes, 11.6%）. The rest of the top two groups were signal transduction genes （137 genes, 11.1%） and proteins binding genes （116 genes, 9.4%）. These comprised 56.8% of all the differentially expressed genes. There were also 207 genes whose functions were unknown （16.7 %）. Therefore it was concluded that differentially expressed genes in high metastatic ovarian cancer cell were supposed to be randomly distributed across the genome, but the majority were found on chromosomes 1, 2, 12, 11, 17, and X. Abnormality in four groups of genes, including in enzyme and its regulator, nucleic acid binding, signal transduction and protein binding associated genes, might play important roles in ovarian cancer metastasis. Those genes need to be further studied.

Expression Profile Changes of Genes Involved in Lipid Metabolism Pathway During Liver Regeneration in Mice

[ Objective ] The aim of the research was to study the expression profile changes of genes involved in lipid metabolism pathway during liver regeneration in mice. [ Method] The CCI4 induced mouse model of liver regeneration was established and the total RNA was isolated from liver tissue of mouse. Then the changes of genes involved in lipid metabolism pathway during different stages of liver regeneration were detected through micro-array chip gene technique and their specific functions were also analyzed. [ Result] Dudng the process of liver regeneration, the expression level of 98 genes involved in lipid metabolism pathway changed, which were divided into eight groups according to change trend. In the mass, the expression of genes was inhibited in the early stage and up-regulated in the late phase. And the gene expression associated with fatty acid synthesis pathway was mainly up-regulated while the catabolic pathway did not change significantly. Most of genes involved in bile acid synthesis pathway were suppressed before 4.5 d and up-regulated after 4.5 d or 7 d. [ Conclusion] During the process of liver regeneration, the genes associated with lipid metabolism are expressed in different trends, and this data should provide a specific range of genes for further studying the regulation effect of lipid metabolism related pathway on liver regeneration.

Genes Expression Profile Difference in Peripheral Blood Between Esophageal Carcinoma Patients and Normal Subjects

Objective： To study the genes expression profile differences in the peripheral blood between esophageal carcinoma patients and normal subjects using the gene chip technique and screen out the esophageal early conceration associated genes. Methods： The total RNA was extracted and purified in the peripheral blood obtained from the patients with esophageal carcinoma and normal subjects. The first strand of cDNA was synthesized through retro-transcription and labeled with Cy5 and Cy3 fluorescence as probes. The mixed probes were hybridized with a piece of 4096 double dot human whole gene chip. The acquired image was analyzed by microarrav suite software using a digital computer, and the intensity of ttuorescence signal and its ratio were calculated. Results： A total of 92 genes were screened out and its expression difference was more than 2 times in the peripheral blood between the patients with esophageal carcinoma and normal subjects. Among these, the expression difference of 36 genes was more than 3 times. Two human urokinase plasminogen activator surface receptor （UPAR） genes, 80K-L protein gene, human protein tyrosine-phosphatase gent arid proto-oncogene protein mRNA were significantly up-regulated, while the collagen V type （α-2 gene was markedly down-regulated. Conclusion： 80K-L protein gene, tyrosinephophatase gene, proto-oncogene protein arid the collagen V type α-2 gene might be associated with the ontogenesis, development and its metastasis in the esophageal carcinoma. The UPAR gene may play important roles in the diagnosing the micrometastasis in the peripheral blood of esophageal carcinoma.

Molecular Detection of Healthiness of Bombyx mori

[Objective] The paper was to explore the regularity between heat shock protein expression and the healthiness changes of Bombyx moil materials. [Method] The representative heat shock protein gene Bmhsp24.3 was screened by bioinfor- matic analysis method, and carried out real-time PCR expression analysis. [Result] The target gene Bmhsp24.3 expressed in different B. mori materials, but the expres- sion level in different materials significantly varied. The relative expression level of the gene had different degrees of changes under different rearing conditions. With the increase of rearing temperature, the gene expression was upregulated. The ma- terials with better healthiness had remarkable increase in expression of target gene, while the materials with poorer healthiness had less increase in expression of target gene. The expression difference of target gene Bmhsp24.3 was exactly consistent with the healthiness of breeds. [Conclusion] The healthiness of materials had rela- tionship with expression of target gene Bmhsp24.3. the higher the expression of tar- get gene Bmhsp24.3 was, the better the healthiness of materials was; conversely, the lower the expression of target gene Bmhsp24.3 was, the poorer the healthiness of materials was.

Aquaporin-8 expression is reduced in ileum and induced in colon of patients with ulcerative colitis

AIM： To study susceptibility genes which may play a potential role in the pathogenesis and etiology of inflammatory bowel disease （IBD）. METHODS： To identify potential susceptibility genes we performed global gene expression profiling in patients with IBD and control specimens. For determination of an intrinsic gene expression profile in ulcerative colitis （UC） and Crohn＇s disease （CD） compared to normal subjects, mucosal biopsies of non-inflamed regions of the colon and the terminal ileum were subjected to DNA microarray analysis. Real-time RT-PCR and immunohistochemistry were used for verification of selected regulated candidate genes and a genetic analysis was performed. RESULTS： We could show that aquaporin-8 （AQP8） mRNA and protein levels were significantly increased in the colon of UC patients compared to controls. Genetic analysis of the six exons and the promoter region of AQPS, however, revealed no mutations or polymorphisms in IBD patients. CONCLUSION： Our results suggest that upregulation of AQP8 in the colon of UC patients represents a secondary phenomenon which may, due to altered water exchange of the distal intestinal mucosa, disturb the physiologic colonic mucus barrier and thus lead to chronic inflao mmation and ulceration.