d—BCS^—的制取及对某些钴（Ⅲ）络合物的拆分与识别研究

研究了用△-(-)_D-[Co(en)_2(C_2O_4]~+及∧-(+)_D-[Co(en)_2(C_2O_4)]~+拆分NH_4(dL-BCS)的方法,制得了两种难溶非对映异构体盐的单晶:△-(-)_D-[Co(en)_2(C_2O_4)](d-BCS).3.5H_2O(Ⅰ)与∧-(+)_D-[Co(en)_2(C_2O_4)](L-BCS)2.5H_2O(Ⅱ)。探讨了晶体中可能的识别模式,用自制的 NH_4(d-BCS)简便地拆分了Cis-[Co(en)_2(NO_2)_2]~+;部分拆分了[(Co(en)_2(gly)]~(2+);讨论了 d-BCS~-对络合物的识别作用。     

1-三氟甲基-β-咔啉-3-羧酸正丁酯的晶体结构研究

通过核磁共振氢谱等对1-三氟甲基-β-咔啉-3-羧酸正丁酯的结构进行表征, 利用单晶X射线衍射法测定其结构.该晶体属单斜晶系,空间群为P21/c, 晶体学参数为:a= 0.81231(4)nm,b = 1.71197(8)nm, c = 1.16388(6)nm; α=90°, β= 93.615(2)°, γ=90°; Z=4, F(000)=696,R1=0.1756.     

凝胶-固相反应法制备SrBi2Ta2O9

以碳酸锶、五氧化二钽、三氧化二铋等物质为原料，采用凝胶一固相反应法制备了SrBi2Ta2O9。利用XRD、DTA、SEM等分析手段对其形成过程和烧结特性进行了研究。结果表明，球磨时间、烧结时间以及烧结温度对烧结密度和SrBi2O9的分解都有明显的影响。介电性能显示，该方法合成的SrBi2Ta209和传统的固相法合成的SrBi2TaO9性能差别不大。     

基于CAN总线的实时数据采集系统

建立基于CAN总线的实时数据采集系统，开发出虚拟设备驱动程序VxD，利用VxD读出数据总线上的数据，存入缓冲区内，采用事件驱动的方式，实现CAN总线与应用层之间的数据通讯，完成高速、实时数据采集。     

Flow-induced release of adenosine 5′-triphosphate from endothelial cells of the rat mesenteric arterial bed

Adenosine 5-triphosphate (ATP) was released into the perfusate of rat isolated mesenteric arterial beds during each of two consecutive increases in flow. There was no significant difference between the amounts of ATP released on each occasion. Substance P was also released into the perfusate by increased flow, although its release was more variable. Removal of the endothelium of the mesenteric vessels with sodium deoxycholate led to a significant reduction (74%) in the amount of ATP released compared with the release before the endothelium had been removed. This suggests that the ATP released into the mesenteric arterial perfusate during increased flow arises from endothelial cells.     

Gigantecin: A novel antimitotic and cytotoxic acetogenin,with nonadjacent tetrahydrofuran rings,fromGoniothalamus giganteus (Annonaceae)

Summary Gigantecin (I), a novel tetrahydroxy-di-tetrahydrofuran fatty acid -lactone (acetogenin), was isolated from an ethanolic extract of the stem bark ofGoniothalamus giganteus Hook. f., Thomas (Annonaceae), by means of activity-directed fractionation (brine shrimp lethality test). This new compound is extremely cytotoxic to human tumor cells, inhibits crown gall tumors on potato discs, and is active in an assay designed to detect antimitotic agents (9 ASK).     

Mg-9Gd-4Y-0.6Mn合金在293～723 K时的变形行为及微观组织演变

研究Mg-9Gd-4Y-0.6Mn 合金在应变速率为0.01 s-1、变形温度为293～723 K时的压缩塑性变形行为, 并在光学显微镜下观察合金在不同变形温度下的表面滑移线及孪生变形形貌与内部微观组织. 研究结果表明： 合金流变应力应变曲线在不同温度呈现出不同的形状, 加工硬化、动态回复和动态再结晶在不同的温度各自起到了重要的作用;在523 K以上时非基面滑移已被激活, 形变孪生在296～723 K范围都存在, 在673 K以上出现动态再结晶;动态再结晶晶粒优先在原始晶界和粗大第二相粒子处形核, 同时在723 K还观察到晶界弓出形核和＂孪生＂动态再结晶现象.     

How retinoids regulate breast cancer cell proliferation and apoptosis

Breast cancer still remains a major problem in its incidence, morbidity and mortality; therefore, more effective strategies for its prevention are urgently needed. Retinoids, natural and synthetic derivatives of vitamin A, possess antiproliferative and proapoptotic properties, making them a promising class of chemopreventive agents against breast cancer. The efficacy of all-trans retinoic acid, 9-cis-retinoic acid, LGD1069 (Targretin, bexarotene), and N-(4-hydroxyphenyl)retinamide (fenretinide) as breast cancer chemopreventive agents is being studied. A better understanding of the molecular mechanisms of action of these agents should lead to improvements in their clinical application. In this review, we discuss the mechanisms by which retinoids exert their antiproliferative and apoptotic effects in breast cancer cells.Received 5 January 2004; received after revision 9 February 2004; accepted 12 February 2004     

Isolation of human epidermal stem cells by adherence and the reconstruction of skin equivalents

The isolation of human epidermal stem cells is critical for their clinical applications. In the present study, we isolated three populations of epidermal keratinocytes according to their ability to adhere to collagen type IV: i.e., rapidly adhering (RA), slowly adhering (SA), and non-adhering (NA) cells. The aim of this study was to characterize RA cells and to investigate the possibility of using these cells for epidermis reconstruction. To identify RA cells, flow cytometric analysis was performed using anti-₆ integrin and anti-CD71 antibodies. RA cells express high levels of ₆ integrin and low levels of CD71, which are considered as markers of an epidermal stem cell nature. Furthermore, electron microscopy showed that RA cells are small and have a high nuclear to cytoplasmic ratio, whereas SA and NA cells have well-developed cellular organelles and abundant tonofilaments. Western blot analysis showed that RA cells are slow cycling and express p63, a putative epidermal stem cell marker, whereas SA and NA cells express c-Myc, which is known to regulate stem cell fate. To compare epidermal regenerative abilities, skin equivalents (SEs) were made using RA, SA, and NA cells. The epidermis constructed from RA cells was well formed compared to those formed from SA or NA cells. In addition, only SEs with RA cells expressed ₆ integrin and ₁ integrin at the basal layer. These results indicate that RA cells represent epidermal stem cells and are predominately comprised of stem cells. Therefore, the isolation of RA cells using a simple technique offers a potential route to their clinical application, because they are easily isolated and provide a high yield of epidermal stem cells.Received 2 July 2004; received after revision 20 August 2004; accepted 10 September 2004