In situ localization and chromosomal mapping of the AG1 (Dmp1) gene

Dentinogenesis is being used as a model for understanding the biomineralization process. The odontoblasts synthesize a structural matrix comprised of Type I collagen fibrils which define the basic architecture of the tissue. The odontoblasts also synthesize and deliver a number of dentin-specific acidic macromolecules into the extracellular compartment. These acidic macromolecules may be involved in regulating the ordered deposition of hydroxyapatite crystals within the matrix. AG1 is the first tooth-specific acidic macromolecule to have been cloned and sequenced. To identify which cells of the rat incisor pulp/odontoblast complex were responsible for synthesis of AG1, in situ hybridization was used. Digoxigenin labeled sense and anti-sense AG1 riboprobes were prepared. The AG1 mRNA was found to be expressed in the mature secretory odontoblasts. Neither pulp cells nor pre-odontoblasts showed any staining with the anti-sense probes. Chromosomal localization studies placed the AG1 gene on mouse chromosome 5q21, in tight linkage with Fgf5. AG1 has been renamed Dmp1 (dentin matrix protein 1) in accordance with present chromosomal nomenclature. Mouse 5q21 corresponds to the 4q21 locus in humans. This is the locus for the human tooth mineralization disorder dentinogenesis imperfecta Type II (DI-II). These data suggest that the Dmp1 gene is involved in mineralization and is a candidate gene for DI-II.     

利用分形几何确定多孔介质的孔尺寸分布

提出了利用分形几何确定多孔介质孔尺寸分布的方法。考虑多孔介质中孔间的屏蔽，采用此方法得到的孔尺寸分布范围比采用平行孔模型宽，分别采用本方法和平行孔模型测定γ－Al2O3催化剂的孔尺寸分布，构造简单立方体三维网络模型模拟压汞过程，并将模拟曲线与γ－Al2O3压汞实验曲线比较，结果表明，采用本方法所得孔尺雨分布优于平行孔模型所得孔尺寸分布。     

基于奇异值分解的特征跟踪方法

在传统的基于模板匹配的跟踪方法中，均是给定一个模板，然后从图像中各个位置取出一个个与模板大小一致的区域进行相似性度量，找出与模板距离最小的一个区域作为当前模板，以便进行下一步的匹配跟踪工作。在景象匹配和相关跟踪过程中，由于所面临的大多数是变化的场景，实时获取的图像与预存模板之间存在比较大的差异，传统相关匹配方法的应用就会受到限制；而且在跟踪过程中，随时更新模板会造成跟踪性能对扰动过分敏感，从而产生漂移。首先拍摄目标不同角度的图像（尽可能包含目标可能出现的所有情况），构成目标图像训练集合，抽取出特征矩阵，对它进行奇异值分解，构成一个关于目标的多维空间。然后再用匹配方法在全局范围搜索，找出目标的大致位置，并利用收敛方法在确定的大致位置内进行搜索，确定目标的仿射变换系数，从而得到一个目标位置的确切描述。     

Feature extraction using orthogonal discriminant local tangent space alignment

A novel algorithm called orthogonal discriminant local tangent space alignment (O-DLTSA) is proposed for supervised feature extraction. Derived from local tangent space alignment (LTSA), O-DLTSA not only inherits the advantages of LTSA which uses local tangent space as a representation of the local geometry so as to preserve the local structure, but also makes full use of class information and orthogonal subspace to improve discriminant power. The experimental results of applying O-DLTSA to standard face databases demonstrate the effectiveness of the proposed method.     

一种针对信息网格RBAC模型私有权限问题的有效解决方案*

针对信息网格RBAC(Role-Based Access Control)模型中由于继承关系产生的子角色不能拥有私有权限的问题进行了研究,并分析了当前提出的使用私有角色和深度指示符这两种解决方法.通过分析得出这两种方法分别存在角色膨胀和组合爆炸的缺点.在此基础上,提出了一种带有权限传播深度的新解决方法,即角色中的每个权限分别具有公有和私有属性以及权限传播深度,同时提供了一个算法求解每个角色的权限集.     

图像的多尺度几何分析概述*

以函数的稀疏表示为主线,详细介绍了各种多尺度几何分析产生的背景、发展历程和逼近性能,并分析了它们各自存在的优缺点,最后指出了其发展方向.     

多信息源下本体自动抽取的实现*

以关系型数据库、XML文件、HTML文件、一般文档为信息源,运用不同的方法分别将多信息源映射为概念图,并按照拟定的概念逻辑结构进行统一存储,最后运用抽取算法实现本体的自动抽取.     

基于GOS的远程实时可视化系统设计与实现*

提出了一个并行计算程序的远程实时可视化系统.通过实时可视化处理计算程序在计算过程中输出的数据文件,实现了对计算程序计算过程的可视化跟踪和实时分析;同时该系统采用GOS作为网格中间件,屏蔽了复杂的异构环境.     

Divergence of Intracellular Trafficking of Sphingosine Kinase 1 and Sphingosine-1-Phosphate Receptor 3 in MCF-7 Breast Cancer Cells and MCF-7-Derived Stem Cell-Enriched Mammospheres

Breast cancer MCF-7 cell-line-derived mammospheres were shown to be enriched in cells with a CD44+/CD24– surface profile, consistent with breast cancer stem cells (BCSC). These BCSC were previously reported to express key sphingolipid signaling effectors, including pro-oncogenic sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate receptor 3 (S1P3). In this study, we explored intracellular trafficking and localization of SphK1 and S1P3 in parental MCF-7 cells, and MCF-7 derived BCSC-enriched mammospheres treated with growth- or apoptosis-stimulating agents. Intracellular trafficking and localization were assessed using confocal microscopy and cell fractionation, while CD44+/CD24- marker status was confirmed by flow cytometry. Mammospheres expressed significantly higher levels of S1P3 compared to parental MCF-7 cells (p < 0.01). Growth-promoting agents (S1P and estrogen) induced SphK1 and S1P3 translocation from cytoplasm to nuclei, which may facilitate the involvement of SphK1 and S1P3 in gene regulation. In contrast, pro-apoptotic cytokine tumor necrosis factor α (TNFα)-treated MCF-7 cells demonstrated increased apoptosis and no nuclear localization of SphK1 and S1P3, suggesting that TNFα can inhibit nuclear translocation of SphK1 and S1P3. TNFα inhibited mammosphere formation and induced S1P3 internalization and degradation. No nuclear translocation of S1P3 was detected in TNFα-stimulated mammospheres. Notably, SphK1 and S1P3 expression and localization were highly heterogenous in mammospheres, suggesting the potential for a large variety of responses. The findings provide further insights into the understanding of sphingolipid signaling and intracellular trafficking in BCs. Our data indicates that the inhibition of SphK1 and S1P3 nuclear translocation represents a novel method to prevent BCSCs proliferation.     

A Strategy of Liquid-Grafted Slippery Sponges with Simultaneously Enhanced Absorption and Desorption Performances for Crude Oil Spill Remediation

Crude oil spill accidents pose a worldwide environmental threat. Oleophilic and hydrophobic absorbents that can selectively absorb oil from water have shown promising application potential in oil spill remediation. Simultaneous optimization of the absorption and desorption speed of absorbents towards oil is highly desirable for their recyclable usage, but remains a great challenge, because these two properties are generally conflicting. Here, a facile and ingenious strategy is proposed to tackle the above challenge via surface modification of porous sponges with highly flexible linear polydimethylsiloxane (LPDMS) brushes. The LPDMS brushes feature liquid-like properties at room temperature owing to its extremely low glass transition temperature, and act as a covalently-grafted lubrication layer throughout the 3D network channels of the sponge, which can minimize contact angle hysteresis and reduce friction between oil and sponge channel. Compared to the prevalent cross-linked polydimethylsiloxane (CPDMS) modification strategy, sponges modified with LPDMS brushes not only shows significantly enhanced absorption speed, but also exhibits superior desorption dynamics towards viscous crude oils. The design strategy of slippery sponges with liquid-like molecules may open a new avenue for developing advanced absorbents with simultaneously enhanced absorption and desorption performances for liquid separation and purification applications.