Integrated Analysis of Microarray,Small RNA,and Degradome Datasets Uncovers the Role of MicroRNAs in Temperature-Sensitive Genic Male Sterility in Wheat

Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.     

Mn、Co掺杂SiC薄膜结构与光致发光性能研究

采用射频磁控溅射技术和复合靶材方法制备了掺Mn,掺Co和Co、Mn共掺的SiC薄膜,经高温退火后进行了光致发光(PL)谱的测量,还用X射线衍射(XRD),傅立叶变换红外光谱(FTIR),扫描电镜(SEM)等表征手段分析了薄膜的相结构和表面形貌,并与光致发光的结果进行了对比研究.结果表明,掺Mn、Co使SiC晶格发生畸变,X射线衍射峰强度下降,Si-C吸收谱变宽,Si-C键振动减弱,Si-O基团的振动增强.样品在室温条件下均呈现出强的紫光发射特性,发光峰均位于414nm(3.0eV),认为414nm处的光致发光峰对应于光激发产生的电子从导带底到Si空位浅受主能级之间的辐射跃迁,其强度取决于Si空位的浓度.     

Hematopoietic–Mesenchymal Signals Regulate the Properties of Mesenchymal Stem Cells

It is well known that the properties of hematopoietic stem/progenitor cells (HSCs), such as their self-renewal ability and multipotency, are maintained through interactions with mesenchymal stem/stromal cells (MSCs). MSCs are rare cells that are present in the bone marrow and are useful for clinical applications due to their functional ability. To obtain the necessary number of cells, MSCs must be cultured to expand, but this causes a remarkable decrease in stem cell properties, such as multipotency and proliferation ability. In this study, we show that the c-Mpl signal, which is related to the maintenance of hematopoietic stem cells, has an important effect on the proliferation and differentiation ability of MSCs. Utilizing a co-culture system comprising MSCs and HSCs, it is suggested that signaling from hematopoietic cells to MSCs supports cell proliferation. Interestingly, the enhanced proliferation ability of the HSCs was decreased in c-Mpl knock-out HSCs (c-Mpl-KO). In addition, the MSCs co-cultured with c-Mpl-KO HSCs had reduced MSC marker expression (PDGFRa and Sca-1) compared to the MSCs co-cultured with c-Mpl-wild-type HSCs. These results suggest that a hematopoietic–mesenchymal signal exists, and that the state of the HSCs is important for the stability of MSC properties.     

扫描电镜法研究硅胶填料的孔结构

硅胶作为色谱分离科学中最常使用的柱填料,其孔结构对色谱的分离性能起决定作用,所以研究填料的孔结构具有重要意义.本文通过对硅胶填料进行包埋切片,然后用扫描电镜观察其孔结构,并将此法与BET法、压汞法等传统方法测得的结果进行了比较,结果表明:此法是这些检测手段的必要补充,并且能为色谱工作者研究填料的孔结构提供更加准确、形象、直观的结构信息.     

2mm HM连接器短路失效分析

通过对2mm HM连接器发生安装短路失效分析发现:连接器端子间多余物是引起该短路故障的主要原因。该多余物为连接器端子冲压时因冲裁不彻底而残留的金属屑。卡在连接器端子与塑胶壳体间的金属屑,在PCBA组装压接过程中,刺破PCB阻焊膜,与顶层铜箔相连,造成短路失效。只有严格控制连接器生产工艺,加强质量检验,才能避免连接器安装短路故障的发生。     

应用OBI系统分析胸部肿瘤调强放疗的摆位误差

目的：应用机载影像系统（on boardinmger,OBl）分析胸部肿瘤调强放射治疗时分次间的摆位误差,并依此计算CTV外扩PTV边界的大小。方法：应用Varian-21EX医用直线加速器治疗47例胸部肿瘤。每周治疗前获取锥形束断层扫描（cone beam computed tomography,CBCT）图像,将CBCT图像和计划CT图像及其靶中心匹配,计算平移和旋转误差。结果：平移误差左右（x）方向为（-0．3194±3．6943）mm,头脚（y）方向为（0．4851±6．2636）mm,前后（z）方向为（0．4144±5．2818）mm;旋转误差冠状面（c）为（0．2080±1．4925）°,矢状面（s）为（0．0922±1．2976）°结沦：对于胸部肿瘤调强放疗（IMRT）,临床靶体积（CTV）到计划靶体积（PTV）的外放边界在左右方向宜为7mm,头脚方向宦为11mm,前后方向宜为10mm。考虑到旋转误差,与靶区比较长时靶区两端外放要更大一些.     

分子束外延碲镉汞探测器的变结面积I-V测试研究

碲镉汞红外探测器的表面钝化处理对器件暗电流有较大影响,决定了器件的探测性能。为了研究表面钝化层不同生长方式对暗电流的抑制效果,使用分子束外延(Molecular Beam Epitaxy, MBE)系统在Si基衬底上生长碲镉汞材料,分别通过磁控溅射和原位钝化方法生长CdTe/ZnS钝化膜层。采用半导体工艺在碲镉汞材料上制备了变面积光伏探测器。通过测试不同钝化膜层器件的暗电流,分析零偏电阻和面积乘积(R₀A)与周长面积之比(p/A)的关系。结果表明,磁控溅射生长钝化层的Si基碲镉汞器件存在较大的隧穿电流,而原位钝化生长钝化层的Si基碲镉汞器件能更有效地抑制表面漏电流。拟合器件R₀A因子随PN结面积的变化,得出原位生长钝化层的器件具有更好的钝化效果。变面积器件的制备和测试能够有效且直观地反映器件性能。