Phase Separation in Methylsiloxane Sol-Gel Systems in a Small Confined Space

The organo-siloxane gel with co-continuous structure derived from methyltrimethoxysilane (MTMS) was synthesized in a confined space between parallel plates by inducing spinodal decomposition during sol-gel transition. The resultant gel morphology was 3-dimensionally observed by laser scanning confocal microscopy (LSCM). The sliced LSCM photographs revealed that the confined gels have inhomogeneity perpendicular to the plate, exhibiting a layered structure. The layered structure can be divided into three regions according to their morphology; interface, near-surface layer, bulk phase. The organo-siloxane depletion layer had formed in the vicinity of both hydrophobic and hydrophilic plates, and the bulk phase had formed slight away from the plates exhibited co-continuous structure. In addition, the confined gels exhibited no shrinkage during drying process that resulted in the larger domain size compared to the monolithic gel. The attractive interaction between the plates and the resultant organo-siloxane phase accounts for the inhibition of shrinkage of confined gels.     

新型高倍显微镜云纹测量技术及其应用

本文介绍了两种新型的高倍显微镜云纹测量技术，即激光扫描共聚焦显微镜（LSCM）云纹法和扫描电子显微镜（SEM）云纹法。阐述了LSCM云纹和SEM云纹的形成及测量原理，同时对此两种云纹法加以对比，比较其各自的特点。此外，还对两种云纹法的应用进行探讨，针对测量物体表面变形和表征物体表面周期性结构特征这两类应用领域，分别以测量多晶铝合金板的残余变形和识别日本纹白蝶翅膀表面结构为例介绍LSCM云纹法的应用，以识别绿带翠凤蝶翅膀表面结构为例介绍了SEM云纹法的应用。实验结果证明了LSCM云纹法和SEM云纹法的可行性、灵活性及高灵敏度特性，均为高效、无损的全场测量技术，在微纳米尺度力学特性测量和表征方面有广泛的应用前景。     

Influence of lattice oxygen stoichiometry on the mechanism of methane oxidation in SOFC anodes

There is growing interest in developing oxide materials for direct hydrocarbon solid oxide fuel cell anodes. In addition to electronic and ionic conductivities, the electrocatalytic activity of these materials is a critical requirement for a high performance anode. In this paper, we present evidence for the important role of variable lattice oxygen stoichiometry and anode geometry in dictating the activity and reaction mechanism of La_0.75Sr_0.25Cr_1 − xMn_xO_3 − δ-based anodes for CH₄ oxidation. Total oxidation of CH₄ is favored by low oxygen vacancy concentration and availability of reducible B-site cations. The non-linear dependence of electrode polarization resistance with current density is attributed to dynamic changes in lattice oxygen vacancy concentration. The relatively high open circuit potential of porous anodes compared with thin films is attributed to an increase in secondary reactions of the fuel within the porous anode.     

幼儿颊黏膜脱落细胞钙离子含量与龋病活跃性检测结果的关系

目的探讨幼儿颊粘膜脱落细胞钙离子含量与幼儿患龋状况以及幼儿龋病活跃性检测结果的关系。方法将50例3～5岁幼儿根据龋蚀指数分为两组：龋病高危组26例、无龋组24例。采用Dentocult SM、Dentocult LB、Cariostat、SCAT 4种方法对幼儿进行龋病活跃性检测。取幼儿颊黏膜脱落细胞,Fluo-3染色,用激光扫描共聚焦显微镜检测细胞内Ca2+的荧光强度值,统计分析其与龋病活跃性的关系。结果高危组幼儿Ca2+荧光强度低于无龋组（P＜0.01）;高危组幼儿颊黏膜内Ca2+的荧光强度与dft、CSI均呈直线负相关关系（均P＜0.01）;3岁组Ca2+荧光强度高于5岁组（P＜0.05）;Ca2+荧光强度分别与Dentocult SM、Dentocult LB及SCAT结果呈等级负相关关系（P＜0.05或0.01）。结论3~5岁幼儿颊黏膜钙离子荧光强度与患龋状况具有一定的相关性,龋坏程度重则细胞内钙离子荧光强度低。幼儿颊黏膜细胞内钙离子的荧光强度可作为筛选龋病易感儿童的一项参考指标。     

Three dimensional microvascular measurements in human endometrium using optical slices from laser scanning confocal microscopy (LSCM)

There is increasing interest in the structure of the microvascular environment in human endometrium because of the recognition of the complexity and functional importance of this tissue. Endometrial microcirculatory networks and their relationships have rarely been studied in three-dimensions.Longitudinal uterine slices containing endometrial tissue were carefully selected from women undergoing a hysterectomy. Formalin-fixed endometrial sections (≤50 μm) representing the fundal and isthmic regions were immunofluorescently labeled with monoclonal antibody (CD34) to target the endothelium of microvessel and fluorescein isothiocyanate (FITC) labeled goat anti-mouse. Digital images were acquired using a Nikon Eclipse E800 microscope equipped with a Radiance 2000 confocal scanning laser attachment. ImarisBasic 4.1 visualization suite was utilized for qualitative interpretation. NeuronTracer 1.0 software was utilized to derive the length and numerical densities.There were significant changes across the phases of the menstrual cycle in functional and basal endometrial layers in vessel length density (LD_v) and branch point density (ND_v) within both fundal and isthmic regions of the uterus (P < 0.001). There was also a significant effect of menstrual cycle phase on mean vessel segment length (SL_v) within each region and within each of the layers (P < 0.001). The capillary radial diffusion distance r(diff) was negatively correlated with LD_v. In general, within each of the menstrual cycle phases, LD_v, ND_v were greater in the fundal than the isthmic regions while, in contrast, SL_v was found to be greatest in the isthmic region.Utilization of immunofluorescence and laser scanning confocal microscopy has enabled us to demonstrate significant vascular changes in human endometrial layers illustrating that in general, within each of the menstrual cycle phases, vessel length and branch point densities were greater in the fundal than the isthmic regions, while vessel segment lengths were found to be greatest in the isthmic region.     

靶向性纳米金探针对宫颈癌细胞的激光扫描共聚焦散射成像

制备了粒径均一的纳米金颗粒, 再对其表面进行叶酸修饰, 制得具有靶向性的纳米金探针. 利用激光扫描共聚焦显微镜(LSCM), 对靶向性纳米金的细胞特异性散射成像进行研究. 实验结果表明, 人宫颈癌细胞(Hela)对纳米金-叶酸的摄取作用强于对纳米金的摄取, 但随着时间的延长, 两者的差别逐渐减小. 表明在适当的时间内纳米金-叶酸探针对宫颈癌细胞具有良好的靶向性.     

基于激光共焦扫描术的亚心形扁藻显微图像与光谱

采用激光共聚焦扫描显微技术,针对亚心形扁藻开展了研究.从获得的488 nm Ar+激光单光子激发的亚心形扁藻自体荧光光谱与图像,可知细胞内有一杯状叶绿体物质,其荧光峰值为682 nm,对应叶绿体发出的红色荧光.在单通道模式下,获得800 nm fs激光双光子激发的扁藻自体荧光光谱与图像,可知每个杯状叶绿体的内部有一个自体荧光更强的圆形物质.在双通道模式下,可分别获得小圆形物质的自体荧光图像,杯状叶绿体自体荧光图像,以及两个通道图像的叠加.进一步获得了双光子藻细胞荧光图的6个主要的荧光峰.采用单光子激光激发可获得亚心形扁藻叶绿体自体荧光图像及其荧光光谱,而双光子激光激发荧光光谱的多通道以及Lambda模式下采集光谱信号与图像,不仅可观察到亚心形扁藻的内部形态结构,还可能从双光子激发荧光图中研究分析亚心形扁藻生化物质的存在,灵敏度较单光子激发高.激光扫描共聚焦显微技术,特别是双光子荧光与图像技术可为海藻的检测与研究提供一种快速、实时、有效、简便的方法.     

Catalysis of the hydrogen oxidation reactions by Sr-doped LaMn1 − yCryO3 ± δ oxides

Sr-doped and Sr-free La_1 − xSr_xMn_1 − yCr_yO_3 ± δ (LSMC, x(Sr) = 0-0.2, y(Cr) = 0.4-0.6) perovskite-type oxides were synthesized and evaluated as single phase anodes for use in intermediate temperature solid oxide fuel cell applications. Their thermo-chemical and chemical stabilities were investigated in hydrogen at high temperatures and correlated with their oxygen non-stoichiometry (3 ± δ), determined by permanganate titration. The catalytic activity towards hydrogen oxidation was examined as a function of oxide sintering time, operating temperature, and the Sr and Cr contents, using a Pt mesh current collector. While all of the perovskite oxides studied here showed some irreversible performance degradation with time under both open circuit and anodically polarized conditions, La_0.9Sr_0.1Mn_0.6Cr_0.4O_3.03 (LSMC9164), sintered at 1200 °C for 10 h, was found to be the most catalytically active and also the most stable.     

In situ visual and content changes analysis of coumarins in Radix Angelicae dahuricae by LSCM combined with LC-MS technology

In this study, a simple, accurate and green localization method of coumarins in Radix Angelicae dahuricae was established with fresh Radix Angelicae dahuricae as research material to reveal the distribution and accumulation of coumarins, based on frozen section and fluorescence imaging technology. The best frozen section conditions were established by comparing the effects of different cryoprotectants on the quality of Radix Angelicae dahuricae's frozen sections, according to the loss of coumarins and the complexity of the operation process. The coumarin components in Radix Angelicae dahuricae at different stages were located and quantitatively analyzed, and coumarin components distribution positions and content changes were identified using fluorescence imaging combined with LC-MS technology. The results showed that 30 μm slice thickness with 15 % glycerin protectant treatment is the best condition for frozen section. Fluorescence imaging showed that coumarins in Radix Angelicae dahuricae were mainly distributed in secretory tissue, the content over different periods showed an “S” curve of growth and coumarins reached their highest content in early September. The distribution and accumulation of coumarins in roots were revealed, which provided a reference for the synthesis and metabolism mechanism of metabolites in medicinal plants and the quality evaluation of traditional Chinese medicine.