模板法制备GdMn_xO_y纳米线阵列及荧光性能

用负压抽滤法,在多孔阳极氧化铝模板(AAO)中制备GdMnxOy纳米线阵列.分别以扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能量色散谱(EDS)、X射线衍射仪(XRD)、选区电子衍射(SAED)表征GdMnxOy纳米线的形貌、组成和结构.实验结果表明:GdMnxOy纳米线尺寸、形貌均一,为非晶态结构,Gd、Mn、O元素的原子百分比是1.65∶0.14∶98.21,用荧光分光光度计(PL,F-4500)表征铕掺杂的GdMnxOy纳米线荧光性能,结果表明:室温下,当激发波长为394 nm时,GdMnxOy:Eu纳米线在593 nm附近有一组强的发射峰,此为5D0-7F1跃迁所致,当Eu3+掺杂浓度比例为4%时,GdMnxOy:Eu纳米线荧光强度最强.     

高校教学评估的反思与走向

自2003年教育部组织实施普通高等学校本科教学工作水平评估开始，教学评估由高校的一项常态工作变成人们热议的话题。通过回顾高校教学评估的发展历程，立足高等教育教学本身，认真反思高校教学评估工作，挖掘高校教学评估责难产生的根源，并结合高校教学评估最新发展，从宏观、中观和微观三个层面探索高校教学评估的走向。     

Visual FoxPro中的索引文件详解

VFP中的索引文件类型较多.本文详细介绍了不同类型的索引文件及特点,同时也介绍了主索引和辅助索引.希望通过本文的介绍能使大家较为准确和熟练地掌握索引文件及其使用方法.     

基于V-A法的光纤式电流测量仪研究

提出了一种适用于超高压输电系统的基于V-A法的电流测量方法,并设计了基于该方法的电流测量仪.该仪器的取样元件为输电导线,采用硅钢片作为高压电源的材料,利用光纤隔离高电位和传递测量信息,能观测系统短路电流的波形,测量误差利用最小二乘法进行补偿,其精度高于0.5级.运行结果表明:该仪器的动态性能优于电流互感器,达到了设计要求.     

Common Molecular Mechanisms of Mammary Gland Development and Breast Cancer

During its lifetime, the mammary gland undergoes many phases of development and differentiation. Much of this occurs during puberty, when the ductal epithelium expands by branching morphogenesis, invading the surrounding fat pad to form an organised mammary tree. Throughout its existence, the epithelium will go through several cycles of proliferation and cell death during pregnancy, lactation and involution. Many of the signalling mechanisms which control the initial invasion of the fat pad by the epithelium, and regulate its continuing plasticity, can be harnessed or corrupted by tumour cells in order to support their aberrant growth and progression towards invasion. This is true not just for the epithelial cells themselves but also for cells in the surrounding microenvironment, including fibroblasts, macrophages and adipocytes. This review examines the complex web of signalling and adhesion interactions controlling branching morphogenesis, and how their alteration can promote malignancy. Current in vivo and in vitro mammary gland models are also discussed. (Part of a Multi-author Review)     

Genetic studies of diseases

Genomic alterations lead to cancer complexity and form a major hurdle for comprehensive understanding of the molecular mechanisms underlying oncogenesis. In this review, we describe recent advances in studying cancer-associated genes from a systems biology point of view. The integration of known cancer genes onto protein and signaling networks reveals the characteristics of cancer genes within networks. This approach shows that cancer genes often function as network hub proteins which are involved in many cellular processes and form focal nodes in information exchange between many signaling pathways. Literature mining allows constructing gene-gene networks, in which new cancer genes can be identified. The gene expression profiles of cancer cells are used for reconstructing gene regulatory networks. By doing so, genes which are involved in the regulation of cancer progression can be picked up from these networks, after which their functions can be further confirmed in the laboratory.     

拉速对0Cr13不锈钢坯壳凝固收缩的影响研究

基于实际钢种物性参数和现场工艺参数,建立了0Cr13不锈钢板坯连铸过程凝固传热和应力模型,研究了不同拉速对坯壳在连铸过程中的凝固收缩和应力应变的影响.结果表明,同一拉速下,出结晶器和不同二冷段凝固收缩先增加后减少且变化量基本一致;拉速从0.75 m/min增加至0.80 m/min,铸坯在结晶器和二冷区各段的铸坯收缩量...     

Investigating the Impact of Capacity Utilization on Carbon Dioxide Emission:Evidence from China's Iron and Steel Industry

In recent years,China's industrialization and urbanization have deepened,and the economy has grown considerably.But at the same time,they have also brought abou...     

Multiple Needle Electrospinning for Fabricating Composite Nanofibers with Hierarchical Structure

Electrospinning is a powerful method for fabricating micro/nano fibers that can be applied to various fields. Composite materials with nanoscale structure can show more excellent properties than their conventional partners. Here, we reported hierarchical structured nanofibers with beads and spheres by double needle electrospinning with an auxiliary airflow. Two different spinning solutions with different concentrations were placed into different syringes. The action of airflow was able to make the two differently morphological nanofibers mixed together evenly. The results showed that the obtained nanofiber membrane has a good hierarchical structure with different morphologies.     

Selective effect of burn injury on splenic CD11c+ dendritic cells and CD8α+CD4−CD11c+ dendritic cell subsets

Burn injury causes an immunosuppression associated with suppressed adaptive immune function. Dendritic cells (DCs) are APCs for which signaling via their Toll-like receptors (TLRs) induces their maturation and activation, which is essential for the adaptive immune response. In this study, we examined if burn injury alters the TLR activity of splenic DCs. After injury, we noticed that DC functions were impaired, characterized by a suppressed capacity to prime naive T cells when triggering the TLR4 signaling cascade using specific ligands (LPS or rHSP60). The observed perturbations on LPS-primed DCs isolated from burned mice exhibited significantly diminished IL-12p40 production and enhanced IL-10 secretion-associated impairment in mitogen-activated protein kinase activation. Interestingly, we observed a decrease of TLR4/MD-2 expression on the CD8α⁺ DC subset that persisted following LPS stimulation. The altered TLR4 expression on LPS-stimulated CD8α⁺ DCs was associated with reduced capacity to produce IL-12 after stimulation. Our results suggested that TLR4 reactivity on DCs, especially CD8α⁺ DCs, is disturbed after burn injury.