Novel spironucleosides: 1",3"-thiazolidine-2"-spiro-3'-3'-deoxyuridine derivatives

Reaction of 2',5'-di-O-TBDMS-3'-ketouridine 1 with L-cysteine yielded in good yield a resolvable mixture of the two expected epimeric spironucleosides 2 and 3. Amidification of their carboxylic group took place readily and the ribo carboxamide 4 was oxidized to the corresponding sulfoxide 6. Despite their similarity to TSAO derivatives these compounds did not exhibit usable anti-HIV activity.     

Computerized 3-D reconstruction of two "double teeth"

"Double teeth" is a root malformation in the dentition and the purpose of this study was to reconstruct three-dimensionally the external and internal morphology of two "double teeth". The first set of "double teeth" was formed by the conjunction of a mandibular molar and a premolar, and the second by a conjunction of a maxillary molar and a supernumerary tooth. The process of 3-D reconstruction included serial cross-sectioning, photographs of the sections, digitization of the photographs, extraction of the boundaries of interest for each section, surface representation using triangulation and, finally, surface rendering using photorealistic effects. The resulting three-dimensional representations of the two teeth helped us visualize their external and internal anatomy. The results showed: a) in the first case, fusion of the radical and coronal dentin, as well as fusion of the pulp chambers; and b) in the second case, fusion only of the radical dentin and the pulp chambers.     

浅谈“3S”在煤炭地震勘探项目中的应用

文中讨论了3S的概念及其相关技术特点,叙述了煤炭地震勘探的作业流程以及项目施工特点,3S技术在煤炭地震勘探项目中的具体应用,以及结合项目生产的实际情况,3S技术存在的一些问题及针对有关问题的几点个人思考。     

3S技术在矿山中应用展望

分析了3S技术的特点,考虑矿区的具体情况和要求,探讨了3S技术应用于矿区工程的可行性和应用目标.     

Sequence-specific dimerization of the transmembrane domain of the "BH3-only" protein BNIP3 in membranes and detergent

Mitochondria-mediated apoptosis is regulated by proteins of the Bcl-2 superfamily, most of which contain a C-terminal hydrophobic domain that plays a role in membrane targeting. Experiments with BNIP3 have implicated the transmembrane (TM) domain in its proapoptotic function, homodimerization, and interactions with Bcl-2 and Bcl-xL. We show that the BNIP3 TM domain self-associates strongly in Escherichia coli cell membranes and causes reversible dimerization of a soluble protein in the detergent SDS when expressed as an in-frame fusion. Limited mutational analysis identifies specific residues that are critical for BNIP3 TM self-association in membranes, and these residues are also important for dimerization in SDS micelles, suggesting that the self-association observed in membranes is preserved in detergent. The effects of sequence changes at positions Ala176 and Gly180 suggest that the BNIP3 TM domain associates using a variant of the GXXXG motif previously shown to be important in the dimerization of glycophorin A. The importance of residue His173 in BNIP3 TM domain dimerization indicates that polar residues, which have been implicated in self-association of model TM peptides, can act in concert with the AXXXG motif to stabilize TM domain interactions. Our results demonstrate that the hydrophobic C-terminal TM domain of the pro-apoptotic BNIP3 protein dimerizes tightly in lipidic environments, and that this association has a strong sequence dependence but is independent of the identity of flanking regions. Thus, the transmembrane domain represents another region of the Bcl-2 superfamily of proteins that is capable of mediating strong and specific protein-protein interactions.     

"三高两低"是电炉炼钢生产技术发展的趋势

根据全国各电炉钢厂提供的３０ｔ以上电炉的炼钢生产技术数据进行了整理和分析,对照国际电炉炼钢的状况提出了抓“三高”－高生产率,高生产速率,高利用系数,促“两低－低消耗,低生产成本的发展电炉炼钢生产技术的观点。     

Toward targeted "oxidation therapy" of cancer: peroxidase-catalysed cytotoxicity of indole-3-acetic acids

PURPOSE: The study aimed to identify suitable prodrugs that could be used to test the hypothesis that peroxidase activity in cells, either endogenous or enhanced by immunological targeting, can activate prodrugs to cytotoxins. We hypothesized that prototype prodrugs based on derivatives of indole-3-acetic acid (IAA), when activated by peroxidase enzymes (e.g., from horseradish, HRP) should produce peroxyl radicals, with deleterious biological consequences. METHODS AND MATERIALS: V79 hamster cells were incubated with IAA or derivatives +/- HRP and cytotoxicity assessed by a clonogenic assay. To assess the toxicity of stable oxidation products, prodrugs were also oxidized by HRP without cells, and the products then added to cells. RESULTS: The combination of prodrug and enzyme resulted in cytotoxicity, but neither indole nor enzyme in isolation was toxic under the conditions used. Although lipid peroxidation was stimulated in liposomes by the prodrug/enzyme treatment, it could not be measured in mammalian cells. Adding oxidized prodrugs to cells resulted in cytotoxicity. CONCLUSIONS: Although the hypothesis that prodrugs of this type could enhance oxidative stress via lipid peroxidation was not established, the results nonetheless demonstrated oxidatively-activated cytotoxicity via indole acetic acid prodrugs, and suggested these as a new type of substrate for antibody-directed enzyme-prodrug therapy (ADEPT). The hypothesized free-radical fragmentation intermediates were demonstrated, but lipid peroxidation associated with peroxyl radical formation was unlikely to be the major route to cytotoxicity.     

济钢1750m^3高炉“零慢风”上料自动化系统的优化

通过对高炉上料自动化系统的优化,降低高炉慢风率,给高炉稳定顺行提供了保证,使高炉操作者更加专注于各项指标的稳步提升,降低炼铁生产成本,实现经济价值。     

以FZ-9538代替丁铵黑药的浮选试验研究

FZ－9538是一种新型快速浮选增效剂,对金、银有特殊的亲合作用。广东高要河台金矿应用该药剂所做的小型试验和工业试验表明,该药剂是适用的。近一个月的工业试验中尾矿累计品位由试验前的0．59g/t降至0．48g/t,回收率提高了1．7％。     

“3D硬金”饰品内部缺陷筛查方法实验研究

针对"3D硬金"饰品可能存在的残留银缺陷,基于X射线对金、银(质量分数达999‰)具有不同的灰度响应,建立了一种筛查"3D硬金"饰品内部缺陷的新方法。实验根据标准样品的测试确定合格样品的灰度相对差值小于0.5%,缺陷样品的灰度相对差值大于0.5%。在实际样品的测试中,通过测定样品厚度计算理论灰度值,并与实际灰度值比较得出相对差值,通过与相对差值阈0.5%的对比确定样品是否存在缺陷。实验结果表明,该方法与化学法测定结果吻合,具有样品损耗少,成本低,效率高等优点。     

河南商南—洛南地区“三稀”及铂族元素异常特征及找矿潜力

“三稀”及铂族元素均为现代高精尖科学技术的重要战略资源。通过对河南省商南—洛南地区地球化学资料的综合整理研究,查明了“三稀”及铂族元素富集分异特征,圈定综合异常13处;根据研究区地球化学异常特征,结合地质特征及成矿作用,划分2处地球化学分区,6处地球化学子区;圈定B级和C级找矿远景区各1处,对各找矿远景区作出了初步评价解译,为研究区“三稀”及铂族元素矿产勘查提供了大量地球化学信息。