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。     

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。     

调幅信号谱相关密度分析中白噪声影响的研究

重点研究了加性高斯白噪声对调幅信号谱相关密度分析结果的影响。平稳信号的谱相关密度仅存在于频率轴上，但是由于谱相关密度分析为非线性二次变换，信号和噪声的交叉项也将干扰分析结果。本文通过对加性高斯白噪声干扰的调幅信号的理论分析，得到了加性噪声干扰在谱相关密度双频率平面上的分布特点，总结了该类型循环平稳信号谱相关密度图的分布规律，最后利用仿真信号验证了理论分析的正确性。     

谱归一化CycleGAN的轴承故障迁移诊断研究

深度学习无需先验特征提取的优点使其受到了工业设备的智能故障诊断领域研究的青睐,但深度学习的低鲁棒性和较高的数据要求阻碍其实际应用。为适应在工业现场复杂多变的工况,该文提出了一种基于谱归一化(spectral normalization, SN)和循环一致对抗网络(cycle-consistent adversarial networks, CycleGAN)的SN-1DCycleGAN网络用于变工况条件下的故障数据迁移生成和诊断。首先,搭建一种适应振动数据生成的1DCycleGAN网络,用于获得同种工况下正常信号与故障信号的映射关系。使用谱归一化对网络进行改进,有效的防止CycleGAN网络训练过程中训练不稳定情况。其次,通过不同工况的正常数据生成自适应的故障数据,实现变工况迁移生成的目的。最后,3种评价指标以及分类器准确率对数据生成质量进行定量评估,并使用仿真与试验信号进行验证。试验结果表明,SN-1DCycleGAN在一维振动信号上具备一定迁移效果,可对变工况数据进行增强,提升分类器的准确率。     

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.     

Assessing the effect of surface chemistry on gold nanorod uptake, toxicity, and gene expression in mammalian cells

Through the use of various layer-by-layer polyelectrolyte (PE) coating schemes, such as the common poly(diallyldimethylammonium chloride)-poly(4-styrenesulfonic acid) (PDADMAC-PSS) system, the mammalian cellular uptake of gold nanorods can be tuned from very high to very low by manipulating the surface charge and functional groups of the PEs. The toxicity of these nanorods is also examined. Since the PE coatings are individually toxic, the toxicity of nanorods coated in these PEs is measured and cells are found to be greater than 90% viable in nearly all cases, even at very high concentrations. This viability assay may not be a complete indicator of toxicity, and thus gene-expression analysis is used to examine the molecular changes of cells exposed to PDADMAC-coated nanorods, which enter cells at the highest concentrations. Indicators of cell stress, such as heat-shock proteins, are not significantly up- or down-regulated following nanorod uptake, which suggests that PDADMAC-coated gold nanorods have negligible impact on cell function. Furthermore, a very low number of genes experience any significant change in expression (0.35% of genes examined). These results indicate that gold nanorods are well suited for therapeutic applications, such as thermal cancer therapy, due to their tunable cell uptake and low toxicity.     

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.     

Modeling and monitoring the nonlinear profile of heat treatment process data by using an approach based on a hyperbolic tangent function

In this article, a new approach is proposed which uses the hyperbolic tangent function to model and monitor vacuum heat treatment process data. The proposed hyperbolic tangent function approach is compared to the smoothing spline approach. The latter serves as the benchmark when the vacuum heat treatment profile is investigated. The vector of the obtained parameter estimates is monitored by using Hotelling's method for the hyperbolic tangent function approach, and the metrics method used for the smoothing spline approach. For the purposes of verification, data from a real aluminum alloy heat treatment process is used to illustrate the proposed approach. In Phase I, the modified hyperbolic tangent function and the smoothing spline are first utilized to fit the process data. The proposed approach provides a better fitting result than the smoothing spline approach. In Phase II, the proposed approach produces a much better out-of-control average run length (ARL) performance than the smoothing spline approach when the heat treatment profile shows process abnormalities.