Quantitative Proteomics Study Reveals Changes in the Molecular Landscape of Human Embryonic Stem Cells with Impaired Stem Cell Differentiation upon Exposure to Titanium Dioxide Nanoparticles

The increasing number of nanoparticles (NPs) being used in various industries has led to growing concerns of potential hazards that NP exposure can incur on human health. However, its global effects on humans and the underlying mechanisms are not systemically studied. Human embryonic stem cells (hESCs), with the ability to differentiate to any cell types, provide a unique system to assess cellular, developmental, and functional toxicity in vitro within a single system highly relevant to human physiology. Here, the quantitative proteomics approach is adopted to evaluate the molecular consequences of titanium dioxide NPs (TiO₂ NPs) exposure in hESCs. The study identifies ≈328 unique proteins significantly affected by TiO₂ NPs exposure. Proteomics analysis highlights that TiO₂ NPs can induce DNA damage, elevated oxidative stress, apoptotic responses, and cellular differentiation. Furthermore, in vivo analysis demonstrates remarkable reduction in the ability of hESCs in teratoma formation after TiO₂ NPs exposure, suggesting impaired pluripotency. Subsequently, it is found that TiO₂ NPs can disrupt hESC mesoderm differentiation into cardiomyocytes. The study unveils comprehensive changes in the molecular landscape of hESCs by TiO₂ NPs and identifies the impact which TiO₂ NPs can have on the pluripotency and differentiation properties of human stem cells.     

Spatial Micropatterning of Growth Factors in 3D Hydrogels for Location‐Specific Regulation of Cellular Behaviors

Growth factors are potent stimuli for regulating cell function in tissue engineering strategies, but spatially patterning their presentation in 3D in a facile manner using a single material is challenging. Micropatterning is an attractive tool to modulate the cellular microenvironment with various biochemical and physical cues and study their effects on stem cell behaviors. Implementing heparin's ability to immobilize growth factors, dual‐crosslinkable alginate hydrogels are micropatterned in 3D with photocrosslinkable heparin substrates with various geometries and micropattern sizes, and their capability to establish 3D micropatterns of growth factors within the hydrogels is confirmed. This 3D micropatterning method could be applied to various heparin binding growth factors, such as fibroblast growth factor‐2, vascular endothelial growth factor, transforming growth factor‐betas and bone morphogenetic proteins while retaining the hydrogel's natural degradability and cytocompability. Stem cells encapsulated within these micropatterned hydrogels have exhibited spatially localized growth and differentiation responses corresponding to various growth factor patterns, demonstrating the versatility of the approach in controlling stem cell behavior for tissue engineering and regenerative medicine applications.     

基于词干的蒙古语语音关键词检测方法的研究

To improve in-vocabulary performance in Mongolian speech keyword spotting task, we propose a Mongolian speech keyword spotting method by searching the stem according to the characteristic of Mongolian word-formation rule. First, Mongolian speech is decoded to lattice file by Segmentation-based LVCSR system, and this lattice file is converted to a confusion network. Then, we detect the keywords according to their stems among the confusion network. Experimental results show that the proposed method outperforms baselines based on word confusion network.     

改进关联规则算法在烟草物流销售规律中的应用

烟草产品在销售过程中产生了大量的历史数据,是否能挖掘出其中潜在的高价值信息对烟草物流公司至关重要.本文采用一种比较高效的fp-growth算法设计了烟草产品销售决策支持系统,实践应用表明改进后的fp-growth算法能快速的发现不同时期烟草产品之间的销售规律和关系,占用内存更小、响应速度更快,为烟草物流公司及时掌握烟草产品之间的销售规律提供了有价值的参考.     

基于VRML97的虚拟现实技术在现代测控系统中的应用研究

归纳了当前在科研和应用领域中的热门课题———虚拟现实技术的含义、“3I”特征及应用形式。提出了虚拟现实技术在现代测控系统中应用研究的实现框架。在此基础上着重讨论了虚拟现实的VRML97的实现。最后进一步展望了该技术在测控领域的发展前景。     

bFGF促增殖后骨髓间充质干细胞向多巴胺能神经元样细胞的分化

目的探讨碱性成纤维细胞生长因子(Basic fibroblast growth factor,bFGF)体外作用于骨髓间充质干细胞(Mesen-chymal stem cells,MSCs)后,诱导其向神经元样细胞和多巴胺能神经元样细胞定向分化的情况。方法从鼠骨髓中获得MSCs,培养传代,用MTT法检测bFGF对骨髓MSCs生长的影响。10 ng/ml bFGF作用2 d后,通过IBMX、细胞因子bFGF、GDNFI、L-1β、中脑神经胶质细胞条件培养基和中脑神经细胞膜碎片等分组联合诱导骨髓MSCs向神经元样细胞、多巴胺能神经元样细胞分化,免疫细胞化学方法鉴定特异标志NSE、MAP-2a,b和TH的表达。结果在一定范围内,bFGF对骨髓MSCs具有明显的促增殖作用。分化的神经元样细胞表达NSE、MAP-2a,b和TH,联合应用GDNFI、L-1β、中脑条件培养基和中脑神经细胞膜碎片诱导7 d后,NSE阳性率为(27.774±2.747)%,MAP-2a,b为(28.006±3.080)%,TH为(3.098±0.352)%。结论体外骨髓MSCs被诱导分化成神经元样细胞和多巴胺能神经元样细胞,为帕金森等中枢神经系统疾病的细胞移植治疗奠定了基础。     

基底动脉闭塞的DSA分析

目的探讨脑干梗死经DSA全脑血管造影证实基底动脉闭塞后的临床与预后,以期对临床治疗有一定的指导意义。方法选取14例在临床中发现并经脑血管造影证实为基底动脉闭塞而临床症状轻微的患者。分析基底动脉闭塞后的临床表现与侧支代偿之间的关系。结果(1)基底动脉近端闭塞,临床表现多以眩晕发作为主(占91%);中段或远端闭塞,则多表现为间断性意识障碍(占66.7%)。(2)基底动脉近端闭塞,侧支血流多由颈外动脉和锁骨下动脉分支及椎动脉颅外段的肌支或脊髓前动脉代偿供血;基底动脉中、远段闭塞,侧支血流多由小脑后下动脉与小脑上动脉吻合(占100%)。结论基底动脉闭塞若侧支代偿充分,可不表现明显的脑干缺血表现或表现轻微。内科治疗效果较好。     

Hematopoietic progenitor constituents and adherent cell progenitor morphology isolated from black-rumped agouti (Dasyprocta prymnolopha, Wagler 1831) bone marrow

Stem cells are present in the adult tissues of most diverse species. Bone marrow is recognized to be the most exploited site to obtain stem cells and cell progenitors. The objective of the present study was to characterize hematopoietic progenitor (HP) morphology and analyze the performance of adherent cell progenitors (ACPs) cultivated in vitro from black‐rumped agouti bone marrow (Dasyprocta prymnolopha). Bone marrow aspirates were obtained from tibia crest and used to prepare histological slides and identify cell morphology. Cells were also scattered on culture plates for later isolation, expansion, and quantification. Smears obtained from bone marrow demonstrated HPs at different stages of maturity. In culture, these cells showed fibroblastoid morphology and a strong tendency to form colonies, demonstrated by the presence of cell aggregates, cytoplasmic elongations lying side by side. An 80% cell confluence was observed at 18 days in culture and progressive reduction in the percentage of nonadherent mononuclear cells. After eight passes, a mean cell viability of 96.07% was observed, from a pool of 1.6 × 10⁷ cells (ACP). Thirteen 25‐cm² culture bottles were trypsinized, resuspended in freezing medium, stored in 14 criotubes at a concentration of 1 × 10⁶ cells per milliliter, and placed in liquid nitrogen at ?196°C. Agouti bone marrow demonstrated high plasticity, moreover different HP lines, and a population of adherent cells demonstrated morphology similar to mesenchymal stem cells in culture. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

烟丝组分的吸湿模型研究

为了研究烟丝主要组分的吸湿平衡规律,用GAB模型获得的叶丝、梗丝、膨胀烟丝在25℃环境下,在45%～75%平衡相对湿度范围内的吸湿平衡,得到优异的拟合精度.结果表明,用GAB吸湿模型计算的叶丝、梗丝、膨胀烟丝的单层含水率（干基）分别为6.14%,7.04%,5.92%.以水活度0.65为安全贮存的临界点,对应于吸湿过程,用GAB模型估计25℃时叶丝、梗丝、膨胀烟丝的安全含水率（干基）分别为16.69%,18.30%,15.00%.研究结果为各组分加工过程各阶段的含水率设计提供了参考.