添加剂对PVDF相转化过程及膜孔结构的影响

研究了PVP、PEG及LiCl 3种成孔添加剂下PVDF DMAc H2 O 添加剂体系的成膜机理 .无论那种添加剂的铸膜液相转换成膜过程中都存在凝胶分相和液液分相两种相变方式 ,在 30～ 6 0℃时凝胶分相在较低的非溶剂浓度下先于液液分相发生 ,LiCl作为添加剂较PEG、PVP对铸膜液有较强的致凝胶作用 ,成膜过程中凝胶分相段时间依PVP、PEG、LiCl的顺序延长 ,导致液液分相初始分相点处聚合物浓度增大 ,阻止了大孔结构的充分发展 .制得的膜依PVP、PEG、LiCl的顺序有效孔隙率和通量降低 ,结晶度升高 .以LiCl为添加剂制得的膜几乎不改变PVDF膜的疏水性 ,而以PVP或PEG为添加剂的膜隔水压差降低约 2 0kPa .     

羰基过渡金属异核原子簇(PPh3)2CuFe2Co(CO)8(μ3-S)和(PPh3)3AuFe2Co(CO)7(μ3-S)的合成与表征

本文利用高压法制备HFe₂Co(CO)₉(μ₃-S),作为原料,经脱质子化作用,再分别与(PPh₃)₂Cu(NO₃)和PPh₃AuCl反应,将Ph₃Cu-或Ph₃Au-联接到原始簇合物的中心骨架上,使簇核扩大,得到了组成为(PPh₃)₂CuFe₂Co(CO)₈(μ₃-S)和(PPh₃)₃AuFe₂Co(CO)₇(μ₃-S)的化合物.文中对此两个新化合物进行了IR,UV,¹H和³¹P NMR.元素分析、熔点测定等性质表征,并对(PPh₃)₂CuFe₂Co(CO)₇(μ₃-S)进行了单晶X-射线衍射分析.两个化合物具有类似的中心骨架,在Fe₂和Co原子三角形的上面和下面分别键联着Cu和S,或Au和S原子,构成了三角双锥结构.其中一个簇合物由二个三苯基膦和八个羰基配位,另一个则由三个三苯基膦和七个羰基配位.     

地锦草总黄酮最佳提取分离工艺的研究

采用四因素三水平的正交实验方法,对地锦草总黄酮的最佳提取工艺进行了探索.采用乙酸乙酯萃取、酸碱沉淀、铅盐沉淀3种方法,对其最佳分离工艺进行了探索.正交实验结果表明:温浸法中四因素对地锦草黄酮的影响顺序为乙醇浓度>样液比>提取温度>提取时间.通过实验得到了地锦草总黄酮的最佳提取工艺:以10倍体积的50%的乙醇水溶液在80℃浸提1 h.地锦草总黄酮的最佳分离方法为酸碱沉淀法.这些数据为中药地锦草的开发和应用提供了科学依据.     

丙烯腈中微量有机杂质的测定

本文采用ＸＥ－６０交联弹性石英性细管柱及４０７有机体埴充柱气色谱法可分分析丙烯腈中有机杂质。通过对柱长、担体粒度、液膜厚度、柱温和载气流量的选择。确定出最佳色 谱条件。     

Al-Zn-Mg-Cu合金双级时效析出行为的TEM研究

Al-Zn-Mg-Cu合金是一种时效强化高强变形铝合金,长期以来广泛应用于航空航天等工业领域[1,2].其性能主要由时效过程中的时效析出相决定.研究不同时效状态下合金时效析出相的显微组织结构,对明确组织与性能的关系、确定合理的热处理工艺、改善合金的综合性能具有重要的理论意义和工程实用价值.     

High-level expression of soluble human β-defensin-2 fused with green fluorescent protein in Escherichia coli cell-free system

Human β-defensin-2 (hBD2), a small cationic peptide, exhibits a broad range of antimicrobial activity and does not acquire any microbial resistance. To produce this uneasily detectable, degradable, and toxic polypeptide efficiently, an alternative approach based on the Escherichia coli cell-free biosynthesis system was proposed. The approach implies that a polypeptide of interest is synthesized as a fusion protein linked to a green fluorescent protein (GFP) through a cleavable spacer. With batch-mode operation, a significant amount of hBD2 fused with GFP (0.25 mg/mL) can be expressed in this cell-free system. The productivity of the fusion protein can be improved up to 1.2 mg/mL by employing a continuous-exchange cell-free system. Furthermore, the GFP moiety provides directly visible and quantitative monitoring of the polypeptide synthesis, and the product is soluble and stable. This work will be helpful in allowing the rapid and visible expression of other similar defensins using an in vitro cell-free system.     

共轭高分子的研究——Ⅶ.脂肪腈类的聚合

<正> 聚腈作为新的一类共轭高分子而引起注意。本文在前报的基础上进一步选择了一系列脂肪腈(乙腈、丙腈、戊腈、庚腈和苯乙腈),系统地研究它们在络合能力较强的付氏试剂(BF_3和TiCl_4等)作用下的聚合反应与机理,同时测定了各聚腈的物理性能。 1.腈的络合聚合 腈类与付氏试剂可形成定组成的络合物结晶:     

Highly efficient nitration of phenolic compounds in solid phase or solution using Bi(NO3)3.5H2O as nitrating reagent

[reaction: see text] Bi(NO(3))(3).5H(2)O was used as an efficient nitrating reagent in the nitration of phenolic compounds to give nitrated phenols in good to high yields. The nitration reaction proceeded smoothly by grinding 1 equiv of phenol, 2-methylphenol, 4-methylphenol, or 4-chlorophenol and Bi(NO(3))(3).5H(2)O, and the nitration of other phenolic compounds could be performed in acetone at ambient temperature (22-30 degrees C).     

Palladium-catalyzed amination of aryl bromides with hindered N-alkyl-substituted anilines using a palladium(I) tri-tert-butylphosphine bromide dimer

An efficient palladium-catalyzed amination of aromatic bromides with hindered N-alkyl-substituted anilines is described, either using the combination of Pd(OAc)(2) and P(t-Bu)(3) or a palladium(I) tri-tert-butylphosphine bromide dimer, [Pd(mu-Br)(t-Bu(3)P)](2), a new, commercially available, and easily handled catalyst.     

Addressing the metabolic activation potential of new leads in drug discovery: a case study using ion trap mass spectrometry and tritium labeling techniques

Metabolic activation of drug candidates to electrophilic reactive metabolites that can covalently modify cellular macromolecules may result in acute and/or idiosyncratic immune system-mediated toxicities in humans. This presents a significant potential liability for the future development of these compounds as safe therapeutic agents. We present here an example of an approach where sites of metabolic activation within a new drug candidate series were rapidly identified using online liquid chromatography/multi-stage mass spectrometry on an ion trap mass spectrometer. This was accomplished by trapping the reactive intermediates formed upon incubation of compounds with rat and human liver microsomes as their corresponding glutathione conjugates and mass spectral characterization of these thiol adducts. Based on the structures of the GSH adducts identified, potential sites and mechanisms of bioactivation within the chemical structure were proposed. These metabolism studies were interfaced with iterative structural modifications of the chemical series in order to block these bioactivation sites within the molecule. This strategy led to a significant reduction in the propensity of the compounds to undergo metabolic activation as evidenced by reductions in the irreversible binding of radioactivity to liver microsomal material upon incubation of tritium-labeled compounds with this in vitro system. With the efficiency and throughput achievable with such an approach, it appears feasible to identify and address the metabolic activation potential of new drug leads during routine metabolite identification studies in an early drug discovery setting.