97 resultados para 4-nitroquinoline 1-oxide
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高效抗逆转录病毒治疗(HAART)的应用,极大的降低了AIDS发病率和死亡 率,延长了HIV感染者的生命。但HIV耐药在很大程度上影响了HAART的疗效, 耐药株的产生成为影响抗病毒治疗效果的主要因素。欧洲、美国的耐药监测技术 规范均推荐在新感染未经抗病毒药物治疗的患者中进行原发耐药检测。我国政府 于2003年底出台了艾滋病治疗的“四免一关怀”政策,陆续在全国范围内开展了大 规模的免费抗病毒治疗,监测我国未经抗病毒药物治疗HIV-1感染者中的耐药情 况可以为制定合理的用药方案和减少耐药毒株出现提供科学依据。 根据世界卫生组织(WHO)的“HIV 耐药监测指南”,无偿献血者中的HIV-1 感染者,可以认定为HIV 新诊断未治疗人群。分析了云南无偿献血者的血浆和 外周血单核细胞(PBMC),研究云南无偿献血人群的耐药状况。 已有实验室血清学方法识别HIV-1 新近感染和长期感染,用BED-CEIA 方 法,在河南、安徽、山西自愿咨询检测(VCT)人群中检出新近感染人群,进行耐 药基因研究, 对照研究了部分长期感染人群。 样品提取核酸后,巢式聚合酶链反应(nested-PCR)扩增pol 基因区(含蛋白酶 区1~99 氨基酸全长和逆转录酶区1~242 氨基酸)。PCR 产物双脱氧法测序,所 得序列与洛斯阿拉莫斯HIV 核酸序列库(Los Alamos HIV Database)标准株构建系 统进化树分析亚型;用斯坦福大学耐药数据库(Standford HIV Drug Resistance Database)分析耐药。 研究发现,云南省2005~2006 年无偿献血者中,有52 例为HIV-1 阳性,其 中49 例血浆和相应的PBMC 样品病毒基因扩增成功。序列分析表明,HIV 病毒 的亚型分布为CRF08_BC (51.0%), CRF07_BC (24.5%), CRF01_AE (20.4%)和B (4.1%);所有样品均未发现蛋白酶抑制剂(PI)耐药基因位点主要突变,只在6 例(11.7%)样品中发现7 例次PI 次要耐药位点突变;另外,在9 例(18.4%)样品中发现10 例次核苷类逆转录酶抑制剂(NRTI) 耐药突变,1 例(2.0%)发生非核苷类 逆转录酶抑制剂(NNRTI) 耐药突变;针对具体药物PI/NRTI/NNRTI 均只有1 例 有潜在的低度耐药,临床仍对药物敏感。PBMC 和血浆的病毒耐药没有显著差异。 从河南、安徽、山西27 个VCT 检测点2006~2007 年采集的10310 例样品 中,通过WB 和BED-CEIA 检测出新近感染人群63 例,分析成功50 例血浆样 品;河南VCT 长期感染样品中随机抽样,分析成功19 例样品。分析成功的69 例VCT 样品中,HIV 病毒株的亚型分布分别为B’ (95.7%),CRF01_AE(2.9%)和 C(1.4%)。上诉样品均未检出PI 主要耐药相关突变,只在26 例(37.7%)样品中存 在27 例次PI 次要耐药相关突变;3 例(4.3%)样品出现6 例次NRTI 耐药相关突 变,7 例(10.1%)样品出现8 例次NNRTI 耐药相关突变。通过与斯坦福大学耐药 数据库比对,没有发现针对PI 类药物的临床耐药;但有2 例(2.8%)针对NRTI 类 药物耐药,1 例有M184V 突变导致对拉米夫定(3TC)和氟代拉米夫定(FTC)高度 耐药;1 例样品存在T215Y、M41L、L210W 三重突变位点,对阿巴卡韦(ABC)、 去羟肌苷(ddI)和坦那夫韦(TDF)中度耐药,对齐多夫定(AZT)和司他夫定(d4T)高 度耐药;针对NNRTI 类药物,有3 例(4.3%)毒株有耐药,1 例有K103N 突变导 致对奈韦拉平(NVP)、地拉韦啶(DLV)和依菲韦伦(EFV)的高度耐药;1 例有Y188L 突变导致对NVP 和EFV 的高度耐药;1 例存在K101E 和G190A 双重突变,导 致对NVP 的高度耐药,对DLV、EFV 和依曲韦林(ETR)中度耐药。 比较长期感染和新近感染者之间的亚型和耐药,未发现显著差异。 研究结果表明,云南、河南和安徽未经治疗HIV-1 感染者中耐药处于低流行 状态。亚型分布云南无偿献血者以CRF_BC 为主,河南、安徽VCT 人群以B’ 为主。应持续在未经治疗人群中进行耐药监测。
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于2010-11-23批量导入
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从长白山森林土壤中分离的放线菌D2 4产生的抗生素对蕃茄灰霉病等蔬菜及经济作物的某些真菌病害有很好的防治效果。通过离子交换和吸附层析对抗生素进行了分离纯化。此抗生素为一种弱碱性水溶性抗生素 ,在酸性和中性条件下稳定 ,在碱性条件下不稳定 ,温度耐受性较强 ,在适宜pH条件下 ,1 0 0℃处理0 .5h ,其活性基本不变。
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以血管细胞粘附分子-1(VCAM-1)基因为靶位点,使用含有荧光素酶报告基因的转染细胞株筛选模型M-4细胞从微生物的代谢产物中高通量筛选能够抑制VCAM-1基因表达的生物活性物质,以期找到能够治疗诸如类风湿性关节炎等免疫性疾病的新型药物。在筛选过程中使用有机溶媒萃取、ODS反相柱层析、HPLC制备等方法,从真菌FO-5897的发酵液中分离到了一个对测活用细胞株的荧光素酶报告基因的表达有中等强度抑制作用的化合物,其IC50为13.8μmol/L,经各种理化性质及1H-NMR分析确定该化合物与文献报道的具有降血脂和抗癌作用的化合物Ascofuranone的结构相同。
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Microstructure and mechanical properties of peak-aged Mg-4.5Zn-xGd (x=0, 0.5, 1.0 and 1.5 wt.%) alloys have been investigated. The results showed that the grain size of the alloys was refined gradually with increasing Gd. Mg5Gd and Mg3Gd2Zn3 phases were found in the Gd-containing alloys. The strengths were greatly improved with Gd additions, and the highest strength level was obtained in the Mg-4.5Zn-1.5Gd alloy, in which the ultimate tensile strength and yield strength were 231 MPa and 113 MPa, respectively.
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Two novel bis(amine anhydride) monomers, N,N'-bis(3,4-dicarboxyphenyl)-1,4-phenylenediamine dianhydride I and N,/N'-bis(3,4-dicarboxyphenyl)-1,3-phenylenediamine dianhydride 11, were prepared via palladium-catalyzed amination reaction of 4-chloro-N-methylphthaliniide with 1,4-phenylenediamine or 1,3-phenylenediamine, followed by alkaline hydrolysis of the intermediate bis(amine imide)s and subsequent dehydration of the resulting tetraacids. A series of new poly(amine imide)s were prepared from the synthesized dianhydride monomers with various diamines in NMP via conventional two-step method.
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Five new complexes based on rare-earth-radical [Ln(hfac)(3)(NIT-5-Br-3py)](2) (Ln=Pr (1), Sm (2), Eu (3), Tb (4), Tm (5); hfac = hexafluoroacetylacetonate; NIT-5-Br-3py = 2-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)-5-bromo-3-pyridine) have been synthesized and characterized by X-ray crystal diffraction. The single-crystal structures show that these complexes have similar structures, in which a NIT-5-Br-3py molecule acts as a bridging ligand linking two Ln(III) ions through the oxygen atom of the N-O group and nitrogen atom from the pyridine ring to form a four-spin system. Both static and dynamic magnetic properties were measured for complex 4, which exhibits single-molecule magnetism behavior.
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Reactions of Zn(BF4)(2) and pyridine-2,4-dicarboxylic acid (2,4-pydcH(2)) in the presence of 1,2-bis( 4-pyridyl) ethylene or 1,3-bis(4-pyridyl) propane under hydro(solvo) thermal conditions yielded two polymorphic metal-organic coordination polymers formulated as Zn-2(OH)(2)(2,4-pydc) (1 and 2). Polymorph 1 features a two-dimensional (2-D) layer-like structure that is constructed by 2,4-pydc ligands bridging between the Zn-OH-Zn double-chain units. Each single Zn-OH-Zn chain is composed of mu(2)-OH groups connecting trigonal bipyramidal and tetrahedral Zn centers. Polymorph 2 is a 3-D coordination polymer containing 2-D Zn-OH-Zn sheets that consist of mu(2)- and mu(3)-OH groups and trigonal bipyramidal Zn centers. The sheets are pillared by 2,4-pydc ligands to form an acentric structural architecture. 1 and 2 are rare examples that the two polymorphs exhibit a centrosymmetric 2-D coordination network and an acentric 3-D coordination network, respectively. The different structures lead to differences in photoluminescent properties and thermal stabilities for 1 and 2.
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A series of optically active poly(ester imide)s (PEsI's) has been synthesized by the polycondensation reactions of new axially asymmetric dianhydrides, that is, (R)-2,2'-bis(3,4-dicarboxybenzoyloxy)-1,1'-binaphthyl dianhydride and (S)-2,2'-bis(3,4-dicarboxybenzoyloxy)-1,1'-binaphthyl dianhydride, and various diamines with aromatic, semiaromatic, and aliphatic structures. The polymers have inherent viscosities of 0.45-0.70 dL/g, very good solubility in common organic solvents, glass-transition temperatures of 124-290 degreesC, and good thermal stability. Wide-angle X-ray crystallography of these polymers shows no crystal diffraction. In comparison with model compounds, an enhanced optical rotatory power has been observed for the repeat unit of optically active PEsI's based on aromatic diamines, and it has been attributed to a collaborative asymmetric perturbation of chiral 1,1'-binaphthyls along the rigid backbones.
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An experimentally simple and inexpensive catalyst system based on hexabutylguanidinium/ZnBr, has been developed for the coupling of carbon dioxide and epoxides to form cyclic carbonates with significant catalytic activity under mild reaction conditions without using additional organic solvents (e.g. the turnover frequencies (TOF, h(-1)) values as high as 6.6 x 10(3) h(-1) for styrene oxide and 1.01 x 10(4) h(-1) for epichlorohydrin). This catalyst system also offers the advantages of recyclability and reusability. Therefore, it is a very effective, environmentally benign, and simple catalytic process. The special steric and electrophilic characteristics of hexabutylguanidinium bromide ionic liquid result in the prominent performance of this novel catalyst system.