基于基因功能表达谱的疾病分类:抗基因缺失的稳健性

利用基因表达谱数据,按Gene Ontology基因功能分类体系,将基因模块化地组织到具有显著生物学意义的低维差异表达功能模块单元中,构造新的指标用于分类疾病样本,从而提出了基于功能表达谱的分析新途径。新算法可稳健地抗基因检测缺失,抗基因表达变异,抗检测误差,并可以显著地降低分类特征维数(参与疾病分类的基因数目)。采用淋巴瘤数据集,比较了基于功能表达谱和常规的基因表达谱的决策树分类器。结果显示,基于功能表达谱可以得到高准确度的疾病样本分类结果,能够直接从功能水平上给出相应的生物学解释。通过仿真分析,进一步显示了基于功能表达谱的分类方法具有抗基因检测缺失的稳健性。     

基于基因芯片的人参作用脑组织抗衰老基因表达谱的研究

针对D-半乳糖造成的小鼠亚急性衰老模型,采用Cy3和Cy5两种不同的荧光染料通过逆转录反应将人参作用前后的小鼠脑组织细胞mRNA分别标记成两种探针,混合后与小鼠基因芯片杂交。借助计算机分析扫描芯片荧光信号图像,寻找出经人参作用后表达有差异的基因。据此研究人参水煎剂对衰老模型小鼠脑组织细胞基因表达的影响,以深入探讨其作用的分子机制。研究表明,微矩阵基因芯片在研究人参作用前后衰老模型小鼠脑细胞基因表达的改变时,具有快速、高通量、高敏度等特点,为运用生物芯片技术研究中药抗衰老机理提供了有价值的方法。     

cDNA芯片缺失值处理对基于基因表达谱的疾病分类的影响

选取了4套cDNA芯片数据,分别运用补零和K近邻的方法,对有检测缺失的基因进行了补缺失值处理,分析了不同处理对支持向量机、K近邻分类器、决策树三种分类器分类效能的影响.结果显示: 在cDNA基因表达谱数据中,对检测缺失率不高于5%的基因补缺失值是一种较好的策略,这样可以保留较多的基因供后续的功能分析,同时仍然能够保持很高的疾病分类效能.     

硫苯酰胺对抑郁症大鼠海马区突触素Ⅰ基因表达的影响

利用逆转录聚合酶链反应(RT-PCR)和免疫组织化学等方法,分别从RNA和蛋白质两方面对硫苯酰胺治疗的和未治疗的抑郁症大鼠海马结构内突触素Ⅰ的表达水平进行对比研究,为临床治疗抑郁症提供分子生物学依据。     

基于循环统计量分析方法的我国干线轨道谱研究

轮轨相互作用产生的振动信号 ,二阶统计特性呈现周期性 ,是循环平稳信号。本文利用循环平稳统计理论 ,分析了二阶统计量循环自相关函数和循环谱密度的特性 ,将其应用于轨道谱特性的研究 ,并与传统方法进行比较 ,显示其在轨道谱数据处理中的优越性。     

基于改进谱聚类算法的复杂产品模块发现方法研究

模块化复杂产品具有耦合性、多层次和重叠性等复杂特征。针对现有模块发现方法不能识别产品架构中的重叠结构,本文在对谱聚类算法进行改进的基础上,提出一种新的复杂产品模块发现方法。该方法能实现复杂产品模块化组织的可视化,发现共享零部件,有助于协同设计和任务间的信息交互。以轮式装载机的工作装置为实例,验证了该方法的可行性。     

基于谱相关的齿轮振动监测技术研究

摘要：齿轮振动信号的特征循环频率具有谐频成分,谐频循环频率簇对应的谱线相关性综合反映了系统中的某种啮合振动或调制现象。以此理论为基础,本文提出了啮合振动监测因子和调制监测因子两种累积能量因子,利用单一传感器采集得到的信号,以全频段信息为依据,进行振动信息的抽取和剥离,实现针对性的齿轮振动监测。实例分析结果证实了基于谱相关的状态监测技术具有较高的灵敏性,能够初步判断系统中的故障所在。     

基于谱相关密度组合切片能量的滚动轴承故障诊断研究

包络解调分析方法是滚动轴承等旋转机械故障诊断的常用方法。当轴承滚动体发生故障时,由于其同时与轴承外、内圈接触,以及受保持架转速的影响,包络解调分析方法通常不能很好提取出滚动体故障通过频率。据滚动轴承发生故障时呈现出的二阶循环平稳特征,提出了基于二阶循环统计量的谱相关密度组合切片能量的滚动轴承故障诊断方法。此方法在一定程度上解决了包络解调分析方法在滚动体故障诊断方面的缺陷,对轴承滚动体的故障诊断具有一定的借鉴意义。     

基于MED与自相关谱峭度图的滚动轴承故障诊断方法

滚动轴承振动信号往往信噪比较低,且具有较强的非高斯噪声,如何选择合适的解调频带一直是故障诊断的难点。自相关谱峭度图(Autogram)是新提出的一种最优频带选择方法,通过计算解调信号的平方包络的无偏自相关的峭度,能够有效地检测到解调频带及其故障频率;但此方法易受到噪声干扰,故障特征识别不明显;基于此,提出了一种基于最小熵解卷积(MED)与Autogram的滚动轴承故障诊断方法;该方法通过MED去除噪声,在得到最佳频带的同时,能够有效地突显故障特征。通过分析仿真信号及实验数据,将所提方法与快速谱峭度及现有方法进行了对比,结果表明,所提故障诊断方法能够准确地检测到解调频带及故障频率,突出故障特征和提高故障检测效果。     

与特定密码函数线性等价的布尔函数谱和自相关特征

对线性等价意义下2个布尔函数的密码学性质的异同做了进一步的分析,得到了一个布尔函数线性等价于某个具有m阶相关免疫性的布尔函数的充分必要条件和线性等价于某个满足k次扩散准则的布尔函数的充分必要条件,在线性等价意义上,给出了由不具有相关免疫性且不满足扩散准则的布尔函数,构造既具有相关免疫性、也满足扩散准则的布尔函数的实例。     

新型高抗草甘膦N-乙酰转移酶基因的分离及其在大肠杆菌中的表达

利用草甘膦极端污染土壤总DNA,构建了元基因组文库,筛选到一个高抗草甘膦的N-乙酰转移酶(N-acetyltransferase,GAT)基因,并利用原核表达系统对该基因进行了功能鉴定,发现其在大肠杆菌BL21中能耐受高达300 mM的草甘膦.研究结果为进行N-乙酰化途径高抗草甘膦机理研究和新型高抗草甘膦转基因作物的开发提供了理论基础.     

基于压缩感知的癌症基因表达数据分类

提出了一种基于压缩感知原理的分类方法.把癌症基因表达数据分类问题归结为求解测试样本对于训练样本的稀疏表示问题,通过求解L1范数意义下的最优化问题来实现.提出的方法与Bagging神经网络和SVM的识别效果做了对比和分析,实验证明基于压缩感知的分类取得了相对较好的效果.     

牙鲆抗菌肽hepcidin基因的克隆及表达分析

采用同源克隆的方法设计简并引物从牙鲆(Paralichthys olivaceus)肝脏中克隆了牙鲆hepcidin抗菌肽基因.牙鲆抗菌肽hepcidin基因组DNA全长821bp,序列分析表明该基因具有3个外显子和2个内含子.cDNA全长588bp,包含一个270bp的开放阅读框,编码一个长89氨基酸的前体肽.RT-PCR分析表明:该抗菌肽基因在正常牙鲆的肝脏、头肾、鳃、脾脏中表达量较高,在心脏、小肠中表达量较低;受到病原鳗弧菌感染的牙鲆各组织该基因表达量明显上升.牙鲆抗菌肽基因的克隆为水产养殖等领域的抗耐病品种的选育提供了基因源,为开发新的生物工程药物提供了基础理论和实验数据.     

Effects of bottom base shapes on burden profiles and burden size distributions in the upper part of a COREX shaft furnace based on DEM

The shaft furnace plays a very important role in the quantity and quality indexes of the COREX process. However, research on burden distribution in the COREX shaft furnace is still immature and in need of further development and improvement. For instance, only a single ring charging process rather than multiple rings or a burden matrix process has been simulated for the shaft furnace in practical operation. Therefore, a three dimensional model of the upper part of COREX shaft furnace is developed in the present study. The model simulates the charging process with multiple rings and is then used to investigate the effects of different bottom base shapes on the burden profiles and radial size distributions. Results show that the last rings (the inner rings) in the burden matrix needs be carefully chosen, especially for the middle mode. The bottom base shape affects the burden size distribution a great deal but the surface burden profile very little at a fixed burden matrix. A bottom base of M shape is strongly recommended to obtain a uniform burden size distribution. The burden matrix and bottom base shape need to be well matched in order to obtain desired gas distributions.     

Investigating the effects of feeding properties on rock breakage by jaw crusher using response surface method and gene expression programming

The present study investigates the effects of feeding properties on rock comminution by a laboratory-scale jaw crusher. For this purpose, detailed crushability tests were carried out on four different rock types to assess their degree of rock crushability (DRC). Various feeding sizes (9.5 – 19 mm) and quantities (500 – 1500 g) were adopted to reveal the choke feeding intensity during crushing actions. The efficiency of feeding properties was investigated through the response surface methodology (RSM). The RSM results demonstrated that the characterized feeding size (F₈₀, mm) dominates the general size reduction, whereas the feeding quantity (m_f, g) is associated with the crushing energy consumption and product flakiness. Therefore, the choke feeding intensity has a direct relation to the m_f and F₈₀. In addition, novel gene expression programming (GEP) models were employed to generate empirical formulations to predict the DRC parameters. The established GEP models have a satisfactory estimation capability. Therefore, the DRC of the investigated rocks can be optimized through the proposed GEP models based on the coupling variables of m_f and F₈₀.     

Decolorization of different dyes by a newly isolated white-rot fungi strain Ganoderma sp.En3 and cloning and functional analysis of its laccase gene

A laccase-producing white-rot fungi strain Ganoderma sp.En3 was newly isolated from the forest of Tzu-chin Mountain in China. Ganoderma sp.En3 had a strong ability of decolorizing four synthetic dyes, two simulated dye bath effluents and the real textile dye effluent. Induction in the activity of laccase during the decolorization process indicated that laccase played an important role in the efficient decolorization of different dyes by this fungus. Phytotoxicity study with respect to Triticum aestivum and Oryza sativa demonstrated that Ganoderma sp.En3 was able to detoxify four synthetic dyes, two simulated dye effluents and the real textile dye effluent. The laccase gene lac-En3-1 and its corresponding full-length cDNA were then cloned and characterized from Ganoderma sp.En3. The deduced protein sequence of LAC-En3-1 contained four copper-binding conserved domains of typical laccase protein. The functionality of lac-En3-1 gene encoding active laccase was verified by expressing this gene in the yeast Pichia pastoris successfully. The recombinant laccase produced by the yeast transformant could decolorize the synthetic dyes, simulated dye effluents and the real textile dye effluent. The ability of decolorizing different dyes was positively related to the laccase activity. In addition, the 5′-flanking sequence upstream of the start codon ATG in lac-En3-1 gene was obtained. Many putative cis-acting responsive elements were predicted in the promoter region of lac-En3-1.     

Analysis of cement pastes and mortars by a combination of backscatter-based SEM image analysis and calculations based on the Powers model

Formation of microstructure in cement pastes and mortars were quantitatively analyzed by the SEM-BSE image analysis. Effects of water/cement ratio and of the addition of mineral admixtures on the contents of unhydrated cement particles and pores were discussed. The proportions of each phase obtained by the analyses were compared with proportions calculated on the Powers model. It was found from comparisons that the volume fractions of the residual cement and pores obtained by the image analysis did not contradict those estimated from the Powers model. Lower water/cement ratio pastes and those undergoing pozzolanic reaction showed less fine capillary pores. It was also found that large capillary pores still remained in the mixtures at long ages. The gel/space ratio in the Powers and Brownyard equation was calculated from the phase constituents determined by the image analysis. For mortars without mineral admixture, the gel/space ratio by the image analysis could be related to the strength.