大鼠肾缺血损伤后肾小管上皮细胞改变的研究

缺血可导致细胞损伤及死亡，缺血的程度不同，导致的后果也不同。本实验用大鼠贤缺血作为模型，观察肾小管上皮细胞结构改变情况，并对有关细胞死亡问题进行探讨。     

Effects of substrate nanopatterning on human osteosarcoma cells (SaOs-2) behavior

Engineering of the cellular microenvironment has become an attractive strategy to guide cellular activities such as spreading, motility, proliferation and differentiation. From a technological perspective, the physical crosstalk between a cell and its surrounding represents a design parameter that may be modulated to achieve desired osseointegration in orthopedic and dental implants. In this study we use a surface engineering approach to tap into the interaction between the cell and its surroundings in order to modulate osteogenic adhesion-dependent differentiation and bone tissue formation.The effectiveness of this approach was studied by observing the in vitro cellular behavior of human osteoblastic cells (SaOs-2) seeded on silicon substrates with different nano-scale surface patterns.Our findings suggest that substrate nanopattern geometry can differentially control early cell differentiation decisions. Interestingly, rescue of the differentiation process by supplementation of growth medium with soluble differentiation factors did not appear to compensate for the differences in the early cellular fate decisions observed on the different patterns. Critically, combining surface topography and soluble differentiation factors appeared to modulate the speed of the differentiation process and its shut down at the end of terminal differentiation. Taken together, our findings suggest that cells recognize physical nano-scale topography as an instructive signal that is integrated to fine-tune the multimodal control and guidance of cell behavior and cell fate. This information may find utility in the design of orthopedic and dental implants or innovative bio-materials for regenerative medicine.     

Ga_(1-x)In_xAs_ySb_(1-y)/GaSb LPE生长及其性质研究

报导了在n型(100)GaSb衬底上,温度为520—530℃时,用液相外延的方法实现了组分在0≤x≤0.19,0≤y≤0.14范围内的Ga_(1-x)In_xAs_ySb_(1-y)四元合金半导体的生长。X射线双晶衍射,电子探针及光学显微镜的观察和分析测试表明:所得外延层的表面形貌和界面特性优良,组分分布和层厚均匀,晶格匹配及单晶性能良好。对外延层表面的氧化情况使用Auger能谱仪进行测试分析。另外,对生长中存在的一些问题进行了讨论。     

Three-dimensional representation and quantification of endosomes in the rat kidney proximal tubule cell.

The organization of the endosomal compartment in the rat kidney proximal tubule cell was studied by computer-aided three-dimensional reconstruction based on tracing of serial thin sections. Besides the well-documented endocytic elements such as small vesicles, tubules and large vacuoles, the endosomal compartment contained a prominent structural complex consisting of a central vacuolar element (with diameters up to 2000 nm) and associated systems of radiating tubular profiles. The large endosomes examined had from two to twenty-four tubules as straight or bending extensions directed randomly from the central vacuole. The tubules were 70-90 nm in diameter and varied with the length up to 1500 nm. Quantitative evaluation from examples of the large endosomes with more than ten tubular extensions, showed that 25-40% of the membrane resided in the tubular portion in contrast to 5-10% of the volume. These results indicate the high efficiency of the role of the endosomal tubules as a mediator of the membrane recycling, because the tubules simultaneously allow retention of most of the content in the central vacuole during the recycling process.     

xPb(Y_(1/2)Nb_(1/2))O_3-(1-x)Pb(Zr_(1/2)Ti_(1/2))O_3铁电陶瓷性能研究

系统地研究了 x Pb(Y1 / 2 Nb1 / 2 ) O3- (1- x) Pb(Zr1 / 2 Ti1 / 2 ) O3三元系铁电陶瓷材料 ,测量并计算了不同组分时的压电常数 (d33 )、介电常数 (εT3 3/ ε0 )、机电耦合系数 (kp、k31 )、以及弹性柔顺系数 (s E1 1 、s E1 2 、s E3 3 ) ,对 0 .0 7Pb(Y1 / 2Nb1 / 2 ) O3- 0 .93Pb(Zr1 / 2 Ti1 / 2 ) O3材料 ,d33 为 32 7× 10 - 1 2 C/ N,介电常数 εT3 3/ ε0 为 135 0 ,机电耦合系数 kp 大于 0 .6 ,弹性常数 SE1 1 和 SE3 3 均大于 17× 10 - 1 2 m2 / N。实现发现 ,当 x大于 0 .5 5时 ,x Pb(Y1 / 2 Nb1 / 2 ) O3- (1- x) Pb(Zr1 / 2 Ti1 / 2 ) O3不再是铁电材料     

Marker proteins of the differentiation of cultured human prostatic epithelial cells

The typical differences in the protein spectrum of cultured epithelial cells of the human definitive prostate and its premordium were revealed by the electrophoresis and electrofocusing procedure. Marker proteins typical of the cultured prostate epithelial cells, which underwent differentiation, have molecular weight of 70000-74000 Dalton and their isoelectric points are 6.6; 7; 7.5.     

Engineering microstructures for efficient Sb2(SxSe1-x)3 solar cells

To realize solar-to-electrical energy conversion,several kinds of solar technologies have been developed since the in-vention of silicon solar cells.Recently,antimony selenosulf-ide Sb2(S,Se)3 (including Sb2S3 and Sb2Se3) has been con-sidered one of the promising emerging materials for solar cell applications due to simple chemical composition,abund-ant elemental storage and excellent stability[1].In terms of prac-tical applications,a solar technology should simultaneously possess high-efficiency,low-cost and long-term stability.The stability for these materials and related devices has already been examined[2-4].In particular,Sb2Se3 solar cells have passed through the stringent stability test[4].Furthermore,the compound is non-toxic and doesn't contain rare ele-ments,which sets the ground for future low-cost production.The optical bandgap for antimony selenosulfide lies in 1.1-1.7 eV[1],falling into the optimal region for sunlight absorp-tion.According to the Shockley-Queisser limit,～32％ PCE can be expected for Sb2(S,Se)3 solar cells.     

紫杉醇抑制原代培养人视网膜色素上皮细胞增殖的实验研究

目的研究紫杉醇(Taxol)对体外原代培养人视网膜色素上皮(human Retinal Pigment Epithelium,hRPE)细胞增殖的抑制作用及机制。方法体外分离、原代培养hRPE细胞,采用免疫细胞化学方法对其进行鉴定。不同浓度紫杉醇(0、0.005、0.05、0.5、5mg/L)处理hRPE细胞一定时间,采用形态学观察、细胞生长曲线及MTT法检测药物对hRPE细胞的生长抑制效应,流式细胞术检测药物对hRPE细胞的细胞周期阻滞作用及凋亡诱导作用。结果原代培养的hRPE细胞胞浆富含色素,随传代次数增加,黑色素颗粒逐渐减少直至消失。用抗人细胞角蛋白抗体进行免疫细胞化学鉴定hRPE细胞呈特异的阳性反应。细胞生长曲线及MTT法显示:紫杉醇作用于hRPE细胞24h和72h,其抑制细胞生长增殖的IC50值分别为5.24和3.24mg/L。流式细胞分析术检测结果显示:0.5mg/L紫衫醇作用细胞48h即可显著延迟hRPE细胞G2/M期进展并诱导凋亡(P<0.05)。透射电镜观察显示:0.5mg/L紫杉醇作用后细胞表面微绒毛减少,电子密度增加,细胞器减少,异染色质聚集成团、边聚等。结论紫杉醇通过阻滞G2/M期进展...     

Synthesis and Characterization of 2D Molybdenum Carbide (MXene)

Large scale synthesis and delamination of 2D Mo₂CT _x (where T is a surface termination group) has been achieved by selectively etching gallium from the recently discovered nanolaminated, ternary transition metal carbide Mo₂Ga₂C. Different synthesis and delamination routes result in different flake morphologies. The resistivity of free‐standing Mo₂CT _x films increases by an order of magnitude as the temperature is reduced from 300 to 10 K, suggesting semiconductor‐like behavior of this MXene, in contrast to Ti₃C₂T _x which exhibits metallic behavior. At 10 K, the magnetoresistance is positive. Additionally, changes in electronic transport are observed upon annealing of the films. When 2 μm thick films are tested as electrodes in supercapacitors, capacitances as high as 700 F cm^?3 in a 1 m sulfuric acid electrolyte and high capacity retention for at least 10,000 cycles at 10 A g^?1 are obtained. Free‐standing Mo₂CT _x films, with ≈8 wt% carbon nanotubes, perform well when tested as an electrode material for Li‐ions, especially at high rates. At 20 and 131 C cycling rates, stable reversible capacities of 250 and 76 mAh g^?1, respectively, are achieved for over 1000 cycles.     

2 1／2维时域有限差分中处理复杂媒质的高效新算法

本文提出了一种用于处理局部媒是电参数剧烈变化或散射体形状较复杂情况下的５／２维时域有限差分算法,即准均匀区域划分的ＦＤＴＤ算法。     

Ultrastructural and functional changes of the proximal tubular epithelial cells in the renal cortex from spontaneously diabetic KKAy mice.

To investigate the morphological and functional changes of epithelial cells of proximal tubules in the early stage of diabetic nephropathy, we examined the ultrastructural changes of proximal convoluted tubular cells in spontaneously diabetic KKAy mice. KKAy mice already showed significant elevation of urinary albumin excretion at 16 weeks of age. Examination revealed that lysosomes were increased in number and conspicuous in the epithelial cells of the proximal convoluted tubules from KKAy mice at 40 weeks of age when compared to control C57BL mice. Furthermore, endogenous IgG was detected in the lysosomes of proximal tubular cells from KKAy mice. These findings suggested that reabsorption activity was elevated in the proximal tubules of KKAy mice at 40 weeks of age.     

对等网络

1 网络资源的变迁,促使网络计算模式发生变化.相应的一种采用对等策略计算模式的网络--对等网络(P2P)得到了广泛关注.P2P是一种分布式网络,网络的参与者共享他们所拥有的硬件资源,这些共享资源能被其他对等结点直接访问而无需经过中间实体.网络中的参与者既是资源提供者,又是资源获取者.为了使读者对P2P有所了解,本讲座将分3期对P2P进行介绍:第1期介绍P2P的拓扑结构、组织模式以及核心查找算法;第2期介绍P2P研究现状、应用情况以及下一步演进与拓展方向;第3期讨论P2P给Internet带来的机遇和挑战,探讨P2P对电信运营商和设备制造商的影响.     

Patterns of cyclic AMP formation by coexpressed D1 and D2L dopamine receptors in HEK 293 cells

Recent studies using immunofluorescence confocal microscopy (Aizman et al., Nature neuroscience (2000) 3, 226-230) present compelling evidence for colocalization of D1 and D2 dopamine receptors on neurons in the striatum and nucleus accumbens. To examine some of the biochemical consequences of colocalization we coexpressed the D1 and D2 dopamine receptors in HEK293 cells. Dopamine D1 and D2 receptors couple to stimulation and inhibition of adenylyl cyclase, respectively. In cells expressing only the D1 receptor, dopamine stimulated cAMP formation with an EC50 of 2.15 nM. In cells expressing only the D2L receptor, dopamine inhibited cAMP formation by 80% with an EC50 of 0.02 nM. The effect of dopamine on the D2L receptor was antagonized by the selective antagonist spiperone with an IC50 of 0.31 nM. In cells coexpressing both the D1 and D2L receptors, dopamine caused an increase in cAMP that was only 20% of that observed with the D1 receptor alone. In this case, increasing concentrations of spiperone caused a change in the dose-response curve from hyperbolic to bell-shaped as the concentration of spiperone was increased. Using pharmacological constants determined from studies on the individually expressed receptors, the curves obtained in cells co-expressing the two receptors could be modeled by kinetic expressions derived by summing the contributions from each receptor. The model leads to a re-interpretation of the pharmacology of dopaminergic ligands. Hence, one consequence of colocalization is that D2 receptor antagonists become functional agonists of cAMP formation.     

新型无铅压电陶瓷NBT-NBSN的研究

采用传统陶瓷制备方法,制备出一种钙钛矿结构无铅新压电陶瓷材料(1-x)(Na1/2Bi1/2)TiO3-x(Na1/2Bi1/2)(Sb1/2Nb1/2)O3(x=0~1.4%,摩尔分数)。研究了(Na1/2Bi1/2)TiO3(NBT)陶瓷B位复合离子(Sb1/2Nb1/2)4 取代对介电和压电性能的影响。X-射线衍射分析表明,所研究的组成均能形成纯钙钛矿(ABO3)型固溶体。陶瓷材料的介电常数-温度曲线显示陶瓷在升温过程中存在两个介电常数温度峰,不同频率下陶瓷材料的介电常数-温度曲线显示该体系材料具有明显的弛豫铁电体特征。检测了不同组成陶瓷的压电性能,发现材料的压电常数d33、厚度机电耦合系数kt和介电常数rε随着x值的增加先增加后降低,在x=0.8%时,陶瓷的d33=97 pC/N,kt=0.50,为所研究组成中的最大值,介电损耗tanδ则随x值的增加而增加。     

Heterologous expression of G protein-coupled receptors in U-2 OS osteosarcoma cells

Recombinant baculoviruses, in which the insect cell-specific polyhedrin promoter has been replaced with a mammalian cell-active expression cassette (BacMam viruses), are efficient gene delivery vehicles for many mammalian cell types. BacMam viruses have been generated for expression of G protein-coupled receptors (GPCRs) and used to establish Ca2+mobilization assays in HEK-293 human embryonic kidney cells and U-2 OS human osteosarcoma cells. U-2 OS cells are highly susceptible to BacMam-based gene delivery and lack many of the endogenous receptors present on HEK-293 and other mammalian cell lines typically used for heterologous expression of GPCRs. U-2 OS cells were found to have a null background for muscarine, ADP, ATP, UTP, UDP, and lysophosphatidic acid (LPA). Consequently, U-2 OS cells transduced with BacMam constructs encoding the muscarinic acetylcholine receptors (M1, M2, M3, M4, and M5subtypes), the P2Y receptors (P2Y1, P2Y2), or the LPA receptors (EDG-2, EDG-7) were used for the establishment of whole-cell Ca2+mobilization assays, assays that cannot readily be established in HEK-293 cells. U-2 OS cells were susceptible to simultaneous expression of multiple genes delivered by BacMam vectors. In U-2 OS cells the functional expression of the Gi-coupled M2and M4receptors was dependent on co-expression of the receptor and a G protein chimera, both of which were delivered to the cells via BacMam viruses. The use of U-2 OS cells and BacMam-based gene delivery has facilitated development of whole-cell-based GPCR functional assays, especially for P2Y, muscarininc acetylcholine, and LPA receptors.     

MBE生长的Al_xGa_(1-x)As合金的光学分析(英文)

Presented here are a combined Rayleigh, Raman and photolumines-cence studies of AlxGa1-xAs alloy grown by molecular-beam-epitaxy. The Rayleigh intensity is found to be sensitive to the degree of disorder in the alloy. The appearance of "forbidden" TO mode in Raman spectra is likely due to twinning effects inducing internal microscopic misorientation. All LO phonons, around X and L points, contribute to the phonon-assisted exciton recombination process examined in photoluminescence spectra. Also shown in the paper is the discrepancy between the results of existing methods to determine alloy concentration from Raman and photoluminescence data.     

应变Si_(1-x)Ge_x材料掺杂浓度的表征技术

在分析研究Si1 -xGex 材料多子迁移率模型的基础上,建立了Si1 -xGex 材料电阻率与其Ge组分、掺杂浓度及温度关系的曲线谱图.同时,通过对半导体材料掺杂浓度各种表征技术的分析和实验研究,提出了采用四探针法表征Si1 -xGex 材料掺杂浓度的技术.此表征技术与Si材料掺杂浓度的在线检测技术兼容,且更加简捷.此表征技术的可行性通过实验及对Si1 -xGex 材料样品掺杂浓度的理化分析得到了验证     

(Na_(1/2)Bi_(1/2))TiO_3-SrTiO_3无铅压电陶瓷的介电、压电性能

研究了 (Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系无铅压电陶瓷的介电、压电性性。Sr2 的引入对 NBT材料的常温介电系数、铁电相与反铁电相转变温度 TF A(180°C)以及居里温度 TC(30 0°C)的影响都不大 ,但却较大幅度地降低了 NBT材料的高矫顽场 ,从而使极化相对容易。(Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系的压电性能参数 d33和 kt分别达到 10 0 p C/N和 0 .45     

非线性光学晶体--MnHg(SCN)4(CH3OCH2CH2OH)的合成及表征

在水和乙二醇－甲醚体积比为1∶的混合溶液中制备了金属有机配合物非线性光学晶体材料；乙二醇－甲醚合硫氰酸汞锰（MMTG）晶体。该晶体具有较强的粉末倍频（SHG）效应，用半定量法测定其SHG强度与Urea晶体相当。该晶体具有较强的红外活性，用红外光谱表征了原子间的振动形式和配位情况。用X射线粉末衍射得到了其粉末衍射数据，对衍射数据进行了指标化，并得出MMTG属于正交晶系，其点阵参数a=1.6219800nm,b1.3502840nm,c=0.7295630nm,V=1.59784nm^2。利用指标化结果和X－射线衍射法（XRD）研究了单晶体生长面的取向。用SEM表征了其形貌。最后用X－射线四周衍射法所得的该晶体的结构数据与粉末衍射数据对比，结果符合较好。并最终确定了MMTG的空间群为p21/c。