共查询到20条相似文献,搜索用时 31 毫秒
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MicroRNAs (miRNAs) are short RNA molecules that negatively regulate gene expression primarily by degrading target mRNA or inhibit the translation of protein product. Recently, many reports have shown the altered miRNA expression in various diseases. However, there are no reports on miRNA expression related to periodontitis. Thus, this study aimed to compare the miRNAs differentially expressed in healthy and chronic periodontitis tissues and to determine the miRNAs closely associated with chronic periodontitis. To find out the miRNAs differentially induced in healthy and chronic periodontitis tissues, miRNA microarray was carried out and the expression of miRNAs was confirmed by real-time PCR. According to miRNA microarray analyses, six miRNA genes, let-7a, let-7c, miR-130a, miR301a, miR-520d, and miR-548a, were up-regulated more than 8 fold compared to the healthy gingiva. The expression of twenty-two miRNAs was increased more than 4 fold. Among these miRNAs, eight miRNAs which are known to be closely related to inflammation were selected. Six of these miRNA genes, miR-181b, miR-19b, miR-23a, miR-30a, miR-let7a, and miR-301a, were amplified successfully and increased much more in periodontitis gingivae than in healthy ones. In summary, this study indicate that six miRNAs up-regulated in periodontitis gingiva may play a key role in chronic periodontitis. 相似文献
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基于质量相似度的Web服务信誉度量 总被引:2,自引:1,他引:1
为提高Web服务信誉度量的灵活性和真实性,提出一种基于服务质量公告值和实际值相似度的Web服务信誉度量模型。通过上、下两层本体,描述了Web服务服务质量的语义和层次化的服务质量指标体系。提出一种支持层次化服务质量指标体系的质量相似度算法,并将质量相似度作为信誉度量的依据。信誉度量算法以统计理论为基础,引入遗忘因子和波动因子,并考虑了服务质量的发展趋势和波动情况对服务信誉的影响。实验表明,该模型具有良好的灵活性和实用性。 相似文献
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以提高产品设计结果的论域覆盖面和增加可行设计结果的多样性为目的,研究了产品概念设计阶段的基于案例推理的产品设计案例相似性检索技术。首先,对产品设计案例相似性检索进行了问题描述;然后指出了传统相似性检索方法的不足;进而提出一种新的基于划分聚类和一般模糊极小极大神经网络的相似案例检索方法,并建立检索模型;最后,通过基于案例推理的固体火箭发动机总体设计实例表明,与传统方法相比,新方法可有效提高相似结果案例集的论域覆盖面,增加设计结果的多样性,提高检索效率,进而提高了固体发动机总体设计质量。 相似文献
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模型相似性评价技术在面向制造设计、净成形加工,以及相似工艺检索等个领域有重要的作用。在对特征模型进行较深入研究的基础上,提出特征模型的相似性比较算法,并根据算法编制出MSAS——模型相似性评估系统,实现基于特征和实例的3维模型相似性评估。 相似文献
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基于工艺相似的冲压件实例检索方法 总被引:2,自引:0,他引:2
为充分应用冲压工艺的成功经验,提出了一种基于工艺相似的冲压件实例检索的方法.首先,从冲压件3维模型中提取特征与特征间约束,并根据冲压件材料信息表,获得材料的厚度、强度和硬度.然后,从工艺相似的角度,分两个阶段计算新旧冲压件实例的相似度.第一阶段以平面为基准计算冲压件拓扑关系相似度,过滤掉一些完全不相似和不太相似的旧实例,得到一批较为相似的旧实例,缩小了后续阶段的检索空间;第二阶段通过比较新旧实例间特征、约束和材料的综合相似度,从第一阶段获得的一批旧实例中得到一个最相似的旧实例.最后,通过实例验证了该方法的有效性. 相似文献
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对等网络环境下基于相似度的任务调度策略研究 总被引:1,自引:0,他引:1
为消除对等环境下任务调度过程中的"颠簸"现象,减少网络开销,提出了能有效利用网络资源的基于相似度的任务调度算法.通过计算现行任务与历史任务之间的相似度,来确定能够直接调度的节点;通过计算任务需求资源与节点可提供资源的相似度并利用传输时间因素对其进行修正,以获取满足任务需求的有序节点集合.在此基础上,利用所提出的任务调度算法,完成任务调度过程.实验结果表明,基于相似度的任务调度算法能够有效地减少任务调度过程中的"颠簸"现象,缩短任务执行时间. 相似文献
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MENGMENG WU PENG GUO YISU SHI DANYAN ZHENG QIAONAN ZHANG XIN JIN YUHUA WANG QIANG LIN RONGJUN FANG WEIGUO ZHAO 《Biocell》2022,46(8):1935-1945
A variety of plants were colchicine treated to double their chromosome number. Chromosomes are genetic
carriers that determine the individual traits of organisms. The doubling of chromosomes will lead to modifications in
plant morphology, physiology and genetics. To determine the response of mulberry trees induced by colchicine, using
mulberry variety Yu-711 leaves as research materials, two small RNA libraries (control and experimental groups) were
constructed. It was found that 45 known miRNA genes and 78 predicted novel miRNA genes in the sequence results.
A comparison of data between the control group and the experimental group revealed 37 differentially expressed
miRNA genes, 19 genes of which were up-regulated and 18 genes of which were down-regulated. Eight miRNAs were
selected from 37 differentially expressed miRNA genes. These miRNAs were verified by quantitative real-time PCR,
and the expression levels of these miRNAs were found to be consistent with those obtained by sequencing, which
proved the accuracy of sequencing results. The PsRNATarget software was used to predict the target genes of 8
miRNAs. The Gene Ontology and Kyoto Encycopedia of Genes and Genomes analysis were used to collect the
functions of target genes and confirm that target genes are mainly involved in biological processes, cell components
and molecular functions. novel-77 miRNA was selected from 37 differentially expressed miRNAs. What will serve as a
fundamental data in understanding mulberry miRNAs function in molecular biology research and further provides
the molecular mechanism of mulberry gene regulation as induced by colchicine is that the prediction of novel_77
precursor sequence and the target gene (XM_010104258.2), as well as the secondary structure analysis. 相似文献
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为充分利用高速切削加工实践中积累的成功经验和数据,提出了运用基于实例推理方法的解决方式。研究了高速切削加工实例的表示方法及实例相似度的性质,将实例的局部相似度分为数值型、无关型、枚举型和依赖型4类,并给出了每种类型的局部相似度的计算方法及实例整体相似度复合算法的计算公式。应用结果表明,所提出的实例及其相似度计算方法是可行的。 相似文献
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微小RNA与肿瘤相关性的研究进展 总被引:1,自引:0,他引:1
microRNA(miRNA)是近年来发现的一类长度为19—25个核苷酸的非编码小分子RNA。它主要通过与靶目标基因3’非翻译区的完全或不完全配对,降解靶目标基因mRNA或抑制其翻译,从而参与调控个体发育、细胞凋亡、增殖及分化等生命活动。实验证据表明,miRNA可通过调控其靶基因参与的信号通路,影响肿瘤的发生和发展,发挥着类似于癌基因或抑癌基因的功能。本文就miRNA的生物学功能、miRNA与肿瘤发生的关系、癌症相关的主要miRNA和癌症治疗的展望等问题进行了概括性的论述。 相似文献
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相似理论及其在机械工程中的应用 总被引:1,自引:0,他引:1
相似理论是描述自然界相似物理现象性质的理论方法.首先介绍相似理论的相似三定理、相似准则求解方法等基本概念,然后介绍相似理论在机械制造中的应用,提出机械系统相似性设计流程,最后以螺杆机械为例说明其在机械设计中的应用,分析表明相似理论在机械工程中有着重要的应用价值. 相似文献
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Static load tests are an important means of supervising and detecting a crane’s lift capacity. Due to space restrictions, however, there are difficulties and potential danger when testing large bridge cranes. To solve the loading problems of large-tonnage cranes during testing, an equivalency test is proposed based on the similarity theory and BP neural networks. The maximum stress and displacement of a large bridge crane is tested in small loads, combined with the training neural network of a similar structure crane through stress and displacement data which is collected by a physics simulation progressively loaded to a static load test load within the material scope of work. The maximum stress and displacement of a crane under a static load test load can be predicted through the relationship of stress, displacement, and load. By measuring the stress and displacement of small tonnage weights, the stress and displacement of large loads can be predicted, such as the maximum load capacity, which is 1.25 times the rated capacity. Experimental study shows that the load reduction test method can reflect the lift capacity of large bridge cranes. The load shedding predictive analysis for Sanxia 1200 t bridge crane test data indicates that when the load is 1.25 times the rated lifting capacity, the predicted displacement and actual displacement error is zero. The method solves the problem that lifting capacities are difficult to obtain and testing accidents are easily possible when 1.25 times related weight loads are tested for large tonnage cranes. 相似文献
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基于最优匹配的三维CAD模型相似性评价算法 总被引:2,自引:0,他引:2
提出一种基于最优匹配的三维计算机辅助设计模型相似性评价算法.根据三维计算机辅助设计模型的边界表示,将相比较的两个计算机辅助设计模型拆分成面,并分别对面进行分类.将两模型中同种类型的面两两匹配,运用相应的准则计算出每对面的相似性系数δij,从而使同种类型的面形成了一个二分图.利用图论中二分图的最优匹配算法,计算出两个模型同类型面中各面的最优匹配方案,并计算出加权最优匹配值,最后将各种类型面的最优匹配值相加得到模型的相似系数,以此作为评价模型相似性的依据.为恰当地评价两个类型相同面的相似性,给出了能够综合反映面几何特征和拓扑特征的评价准则.试验表明本方法能够客观地反映两计算机辅助设计模型的相似程度,并较好地反映人视觉上的相似经验. 相似文献
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相似性度量的选择是谱聚类算法良好性能实现的关键。通常采用的谱聚类相似性的度量是基于高斯核函数的相似性度量。然而,谱聚类对这种相似度度量中的尺度参数非常敏感,并且确定一个合适的参数也很困难。另外,基于欧几里得的这种高斯核相似度度量无法有效反映复杂分布数据集的分布特点。针对此问题,通过利用基于核模糊C均值聚类算法得到的划分矩阵中隶属度的分布特点,提出了一个新的核模糊相似度度量,并将基于所提出的新的相似度度量的谱聚类算法(KFSC)应用于图像分割中。所提出的KFSC算法不仅克服了谱聚类对尺度参数敏感,而且解决了尺度参数很难确定的问题,获得更好的聚类效果。3个标准数据集、2个合成纹理图像及2个自然图像上的分割实验表明了所提出算法的有效性和鲁棒性。 相似文献
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针对在大视差场景下进行图像拼接时容易出现的扭曲、失真、重影等现象,提出了一种基于全局相似性约束的多视点图像拼接算法。在传统细分网格模型的基础上,添加一个先验的全局相似约束项,对待拼接图像在整体上进行相似性转化,同时分别选取视角不同、亮度不同、复杂场景的三组图像,与已有算法的拼接效果进行对比,并采用质量评价方法对图像进行客观评价。结果表明:提出的方法在拼接效果上可以有效降低已有方法对大视差图像拼接时产生的扭曲和重影,且质量评价提高了10%以上;由于对图像的视角及场景深度无严格要求,因而具有良好的适应性,能够更自然地拼接大视差图像。 相似文献
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基于模糊集相似度量的装载机臂方案选择方法 总被引:1,自引:1,他引:0
描述了模糊集之间的相似度量与加权相似度量方法,根据模糊集之间的相似度量提出了装载机臂方案的选择方法。在臂部机构方案选择中,模糊集之间的相似度量是评价机构设计方案接近期望方案(理想方案)的度量,相似度量值越大,机构设计方案越接近期望方案。通过实例阐明模糊集之间的相似度量在装载机臂的方案选择中是可行的。 相似文献
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《Measurement》2016
A lot of studies confirmed the seriousness of breast cancer as the most tumors lethal to women worldwide. Early detection and diagnosis of breast cancer are of great importance to increase treatment options and patients’ survival rate. Ultrasound is one of the most frequently used methods to detect and diagnosis breast tumor due to its harmlessness and inexpensiveness. However, problems were found in the tumor diagnosis and classification as benign and malign on ultrasound image for its vagueness, such as speckle noise and low contrast. In this paper, we propose a novel breast tumor classification algorithm that combines texture and morphologic features based on neutrosophic similarity score. Then, a supervised feature selection technique is employed to reduce feature space. Finally, a support vector machine (SVM) classifier is employed to prove the discrimination power of the proposed features set. The proposed system is validated by 112 cases (58 malign, 54 benign). The experimental results show that such features set is promising and 99.1% classification accuracy is achieved. 相似文献