Chiral sulfoxides as neutral coordinate-organocatalysts in asymmetric allylation of N-acylhydrazones using allyltrichlorosilanes

Sulfoxides were first introduced to the allylation of N-acylhydrazones with allyltrichlorosilanes as effective neutral coordinate-organocatalysts (NCOs). Both high diastereo- and enantioselectivity were attained when optically active chiral sulfoxides were used. Asymmetric crotylations using (Z)- and (E)-crotyltrichlorosilanes showed a high level of stereospecificity (Z --> anti and E --> syn) with high enantioselectivity.     

Vinylic polymerization of Norbornenecarboxylic Acid Esters by Palladium Complexes

In recent years certain new technologies demand optically transparent high Tgpolymer materials.Some aliphatic polymers containing cyclic structure are in the marketalready and have been applied to manufacture various devices in optics industry.However,these polymers are usually of nonpolar character and their difficulties inadhesion and solubility in solvents limited their applicability in many technologies[1 ,2 ] .The polymerization of polar group-containing internal cyclic olefins by transit…     

Rare Earth Metal-Initiated Polymerizations of Polar and Nonpolar Monomers

Abstract

Organolanthanide(III) initiated polymerization of methyl methacryate gave both syndiotactic and isotactic living polymers of high molecular weight. Organolanthanide(III) initiated polymerization of alkyl acrylates also gave high molecular weight poly(alkyl acrylate)s with very narrow molecular weight distribuion in high yield. Molecular weights of the resulting polymers increased linearly with the conversion. Random and block copolymerizations of alkyl acrylates with methyl methacrylate were realized successfully. For the sake of development of the olefin polymerization catalyst, bulky substituents were introduced into Me₂Si bridged Cp rings and they were used as ligands for the lanthanide complexes. Tri- and divalent lanthanide complexes with such ligands showed high activity for olefin polymerization and gave high molecular weight polyolefins.     

毒死蜱分子印迹聚合物微球的制备及结合特性的研究

采用无皂乳液聚合法制得的微米级聚苯乙烯微球为种球,以毒死蜱为模板分子,通过单步溶胀聚合法制备了单分散分子印迹聚合物微球（MIPMs）。通过紫外光谱研究了MIPMs的结合机理和识别特性;利用红外光谱分析MIPMs的结合位点;运用扫描电子显微镜对微球进行形貌分析,MIPMs的粒径分布为0.5～3 μm（UMIPMs为2～3 μm）,其表面粗糙具有一定层次孔径分布的多孔性聚合物,有利于底物和结合位点的接触,从而获得高负载量和高效识别性;Scatchard 分析表明MIPMs在识别毒死蜱过程中存在两类结合位点,计算得高亲和性位点的解离常数为 KD1 = 0.526 mmol/L,最大表观结合量Bmax1 = 35.91 μmol/ g,低亲和位点的解离常数为 KD2 = 2.19 mmol/L,最大表观结合量Bmax1 = 83.87 μmol/g。     

Preparation and electrochemical property of Fe2O3 nanoparticles-filled carbon nanotubes

Fe(2)O(3) nanoparticles with a mean diameter of ~9 nm were homogeneously filled into the hollow core of high aspect ratio CNTs synthesized by the AAO template method with tunable filling ratios. These Fe(2)O(3)-filled CNTs were employed as the anode material of lithium-ion battery, and desirable electrochemical properties of high reversible lithium storage capacity and good rate capability were demonstrated.     

Lipid lowering effects of high linoleate and high alpha-linolenate diets in rats and mice. Consequence of long-term feedings.

Diets high in linoleate (safflower oil) or high in alpha-linolenate (perilla oil) were fed to rats for 11 months, and the effects of the diets on plasma and tissue lipids were compared. The plasma levels of total cholesterol (Cho), phospholipids (PL) and triacylglycerol (TG) were significantly lower in the high alpha-linolenate group than in the high linoleate group, the differences being more than 30% in the levels of total Cho and TG. The diets had differential effects on the lipid contents of major tissues: the TG level in muscle was higher but both the TG level in depot fat and the PL level in muscle were lower in the high alpha-linolenate group than in the high linoleate group. In order to clarify whether or not the hypolipidemic effect of the high alpha-linolenate diet was due to changes in the distribution of lipids among tissues, whole body lipids were estimated in mice fed these diets for 5 months. The whole body Cho content was significantly lower, by 28%, in the high alpha-linolenate group compared with the high linoleate group, but the total lipid content, PL and neutral lipids were similar between the groups. Our results indicate that the high alpha-linolenate diet has a more potent cholesterol lowering effect in plasma and body tissue than the high linoleate diet; interestingly, whole body TG levels are similar but tissue distributions of TG are different between the two dietary groups.     

Catalytic,asymmetric Mannich-type reactions of N-acylimino esters: reactivity,diastereo- and enantioselectivity,and application to synthesis of N-acylated amino acid derivatives

In the presence of a catalytic amount of Cu(OTf)(2)-chiral diamine 3e complex, N-acylimino esters reacted with silyl enol ethers to afford the corresponding Mannich-type adducts in high yields with high enantioselectivities. A wide variety of silyl enol ethers derived from ketones, as well as esters and thioesters, reacted smoothly. In the reactions of alpha-substituted silyl enol ethers (alpha-methyl or benzyloxy), the desired syn-adducts were obtained in high yields with high diastereo- and enantioselectivities. Several intermediates for the synthesis of biologically important compounds were prepared using this novel catalytic asymmetric Mannich-type reaction, and at the same time, absolute and relative stereochemical assignments were made. In addition, it has been revealed that alkyl vinyl ethers reacted with N-acylimino esters in the presence of a catalytic amount of the Cu(II) catalyst to give the corresponding Mannich-type adducts in high yields with high enantioselectivities. This is the first example of catalytic asymmetric Mannich-type reactions with alkyl vinyl ethers. The reaction mechanism, structure of chiral catalyst-electrophile complexes, and transition states of these catalytic asymmetric reactions were assumed based on X-ray crystallographic analysis of the Cu(II)-chiral amine complex, PM3 calculations, and FT-IR analyses, etc. Finally, (1R,3R)-N-(3-hydroxy-1-hydroxymethyl-3-phenylpropyl)dodecanamide (HPA-12, 1), a new inhibitor of ceramide trafficking from endoplasmic reticulum to the site of sphingomyerin (SM) synthesis, has been synthesized efficiently using the present Mannich-type reaction as a key step. The synthesis involved three steps (two-pot), and total yield was 82.9%.     

对苯二胺分子印迹聚合物的分子识别特性

以对苯二胺(p-PD)为模板分子,分别以甲基丙烯酸(MAA)和丙烯酰胺(AA)为功能单体,制备了p-PD的印迹聚合物P(MAA)和P(AA),采用色谱法考察了其分子识别特性。结果表明,P(AA)对p-PD无明显的印迹效应;而甲醇为流动相时,P(MAA)能够选择性结合p-PD分子(k′=3.57),对p-PD有显著的印迹效应(印迹因子IF=2.95),P(MAA)柱可以实现p-PD与邻苯二胺(o-PD)和对氨基苯甲酸(p-ABA)的色谱分离。通过光谱实验及HF/6-31G*量化理论计算方法,对比研究了p-PD与MAA和AA之间的相互作用。MAA与p-PD能够形成更稳定的复合物,P(MAA)对p-PD具有更好的分子识别能力。研究表明紫外吸收光谱法和荧光光谱法以及量子化学理论计算法可作为功能单体筛选的有效手段;对于荧光模板分子,荧光光谱法具有简便、灵敏等特点。     

Glycation of human serum albumin in long-term incubation with low and high concentrations of glucose

Glycated albumin levels of incubation mixtures with high (25.8 mM) and low (8.2 mM) concentrations of glucose when measured by the nitroblue tetrazolium (NBT) reducing method, showed similar values at day 20-25. But when tested by thiobarbituric acid (TBA) colorimetry, the levels with high concentrations of glucose were about twice that with low concentration of glucose.     

Facile Synthesis of Functional Poly(methyltriazolylcarboxylate)s by Solvent-and Catalyst-free Butynoate-Azide Polycycloaddition

The copper-catalyzed and metal-free azide-alkyne click polymerizations have become efficient tools for polymer synthesis. However,the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely employed to construct functional polymers. Herein, the polycycloadditions of dibutynoate(1) and tetraphenylethene-containing diazides(2) were carried out at 100 °C for 12 h under solvent-and catalyst-free conditions, producing soluble poly(methyltriazolylcarboxylate)s(PMTCs) with high molecular weights in high yields. The resultant polymers were thermally stable with 5% weight loss temperatures up to 377 °C. The PMTCs showed aggregation-induced emission(AIE)properties. They could work as fluorescent sensors for detecting explosive with high sensitivity, and generate two-dimensional fluorescent photopatterns with high resolution. Furthermore, their triazolium salts could be utilized for cell-imaging applications.     

高硒情况下维生素E对老龄大鼠血清中抗氧化作用的影响

研究了高Se或高维生素E下，老龄大鼠体内抗氧化活性的变化以及高Se下维生素E对其体内抗氧化水平的影响。将十二月龄Wistar大鼠32只随机分成4组：（1）正常饲料组；（2）高Se饲料组；（3）高维生素E饲料组；（4）高Se高维生素E饲料组。饲至十周末，处死大鼠，按试剂盒要求取其血液制成血清测GSH－Px,SOD活性，MDA含量。结果表明，高Se或高维生素E下饲养下的大鼠与对照组比较，血清中GSH－Px活性升高（P＜0．05）。SOD活性未见改变，MDA含量分别减少50％和56％，有显著差异（P＜0．01）；维生素E与高Se合用与高Se组比较能进一步同GSH－Px,SOD活性（P＜0．01）。结论：高Se会升高老龄大鼠的抗氧化活性，而与维生素E合用更加升高老龄大鼠血液中抗氧化活性。     

MCM-48介孔分子筛的高压合成

采用正硅酸乙酯（TEOS）作硅源,十六烷基三甲基溴化铵（CTAB）为模板剂,在高压 （约7 MPa）和373 K下合成了MCM-48介孔分子筛.用XRD、氮气吸附及29Si MAS NMR对样品 进行了表征.与常压合成的相比,高压下合成的MCM-48具有更高的热稳定性和水热稳定性.2 9Si MAS NMR结果表明,高压有利于分子筛孔壁的聚合,导致分子筛结构更加完善,从而使 其具有更高的稳定性.     

固定化β-葡萄糖醛酸酶反应器的制备及其在4-甲基亚硝胺基-1-(3-吡啶)-1-丁醇的O-糖苷化合物分析中的应用

采用溶胶-凝胶法,以丙烯酰胺作为单体,制备了基于有机-硅胶杂化整体柱的β-葡萄糖醛酸酶反应器。优化了硅酸甲酯和γ-(甲基丙烯酰氧)丙基三甲氧基硅的物质的量的比、丙烯酰胺和聚乙二醇的用量,以及水浴温度等制备条件,获得了孔隙均匀、通透性良好、机械强度高的有机-硅胶杂化整体柱。采用光学显微镜和扫描电镜表征杂化整体柱。进一步将β-葡萄糖醛酸酶共价键合在整体柱上,以4-甲基亚硝胺基-1-(3-吡啶)-1-丁醇(NNAL)的O-糖苷化合物(NNAL-O-Gluc)为底物研究酶反应器的水解效果,实验结果证明酶反应器在室温条件下的水解效率大大提高,实现了NNAL-O-Gluc高效水解与分析,解决了目前NNAL-O-Gluc分析中前处理水解效率低的问题。     

Molecular weight determination of high molecular mass (glyco)proteins using CGE-on-a-chip, planar SDS-PAGE and MALDI-TOF-MS

The molecular weights (MW) of seven (glyco)proteins, of which five were plasma-derived, with MWs higher than 200 kDa were determined with three techniques: CGE-on-a-chip, SDS-PAGE and MALDI-TOF-MS. While the analysis of medium to high MW proteins with SDS-PAGE was an already well-established technique, the usefulness of MALDI-TOF-MS for the exact MW determination of high mass proteins was only partly described in literature so far. CGE-on-a-chip is the newest of all three applied techniques and was so far not applicable. Therefore, it was not evaluated for high MW (glyco)proteins. All proteins were analyzed under nonreducing as well as reducing conditions. In this work, it was demonstrated that all three described techniques were capable of determining the MW of all high molecular weight (glyco)proteins. The noncommercial CGE-on-a-chip assay allowed for the first time the electrophoretic separation of proteins in the MW range from 14 to 1000 kDa. MW assignment was limited to 500 kDa in the case of SDS-PAGE and 660 kDa in the case of the high MW CGE-on-a-chip assay. With the proper matrix and sample preparation, analysis with a standard MALDI-TOF-MS provided accurate MWs for all high MW proteins up to 1?MDa.     

Evaluation of the system performance and clinical images of the single photon emission computed tomography for head using ring arranged detector

To evaluate the system performance, several preoperational fundamental tests of single photon emission computed tomography (SPECT) were carried out. Spatial resolutions (FWHM) measured with the point-spread functions of a 99mTc line source were 12.5 mm with a high resolution (HR) collimator and 17.2 mm with a high sensitivity (HS) collimator respectively. Slice thicknesses (FWHM) obtained from the profile curves of slice images were 17.5 mm (HR) and 29.0 mm (HS) at the center of rotation. System sensitivities were 5.4 kcps/slice (HR) and 27.8 kcps/slice (HS). Uniformities calculated from the SPECT images of a pool phantom were 4.7% (HR) and 2.7% (HS) at the condition of 3,000 kcounts to be acquired. SPECT images of the HEADTOME SET-031 were considered very useful to diagnose the cerebrovascular disease.     

一种含树枝单元的高流动性尼龙6的原位聚合及性能测试

将低代数的树枝状大分子聚酰胺胺(polyamidomine,即PAMAM)分别与对苯二甲酸配制成母盐溶液,再以母盐溶液,己内酰胺,封端剂一起投入高压釜进行原位聚合,通过调节PAMAM在己内酰胺中的比例及改变不同的PAMAM代数得到新型高流动性尼龙6.FTIR显示,与线性尼龙相比较,高流动性尼龙6的γ(N—H)和2δ(N—H)两处对应峰都发生了明显的蓝移.对于树枝单元含量较低(0.3 wt%~0.5 wt%)的新型尼龙6,拉伸性能没有下降,缺口冲击强度增加,而熔体流动却显著得到改善.DSC显示,新型尼龙6的结晶曲线的结晶峰温度有不同程度的降低,晶体生长速率明显减慢.     

Investigation of VUV Photodissociation Propensities Using Peptide Libraries

PSD does not usually generate a complete series of y-type ions, particularly at high mass, and this is a limitation for de novo sequencing algorithms. It is demonstrated that b(2) and b(3) ions can be used to help assign high mass x(N-2) and x(N-3) fragments that are found in vacuum ultraviolet (VUV) photofragmentation experiments. In addition, v(N)-type ion fragments with side chain loss from the N-terminal residue often enable confirmation of N-terminal amino acids. Libraries containing several thousand peptides were examined using photodissociation in a MALDI-TOF/TOF instrument. 1345 photodissociation spectra with a high S/N ratio were interpreted.     

电感耦合等离子体质谱(ICP-MS)法测定高钨基体样品中稀土元素的含量

准确测定钨矿和钨酸盐晶体等高钨基体样品中稀土元素的含量有助于开展矿床地球化学特征研究及钨酸盐激光晶体材料的制备和性质研究。在高钨基体样品电感耦合等离子体质谱法（ICP-MS）分析时,为了考察高钨及高含量阳离子等基体组成对分析结果的影响,实验针对Na2WO4、CaWO4、NaY(WO4)2、MnWO4和(Fe,Mn)WO4等高钨基体样品,采用硝酸和氢氟酸高压密闭消解,加入稀土元素并用2% HNO3溶液稀释定容配制成稀土元素浓度为1 ng·g-1的基体匹配标准溶液;同时,直接用2% HNO3溶液配制稀土元素浓度相同的非基体匹配标准溶液以对比系统考察两种基体溶液中稀土元素的相对灵敏度系数（RSC）差异。结果显示,基体匹配溶液与2% HNO3溶液中稀土元素的RSC相对偏差基本小于15%,表明基体效应的影响可以忽略不计。进而,为了准确测定常见高钨基体样品中稀土元素的含量,实验建立了基于ICP-MS的高钨基体样品中稀土元素准确定量分析方法,该方法线性关系好（R2 ? 0.9997）,检出限低（0.5 ~ 27.9 pg·g-1）,准确度理想（相对误差-6.25 ~ 10.74%）。采用该方法测定了钨酸钙单晶实际样品中稀土元素的含量并将其与基体匹配法的测定结果进行比对,结果显示两者相对偏差为0.80 ~ 12.75%,说明本文所建立的分析方法可靠,能用于定量测定高钨基体样品中稀土元素的含量。     

离子色谱法检测高纯硅微粉中痕量铁和氧化铁杂质

建立了柱后衍生-紫外检测-离子色谱法同时测定高纯硅微粉中痕量铁和氧化铁杂质含量的方法。方法选用具有阴阳离子交换基团的高选择性Thermo Scientific Dionex^TM IonPac^TM CS5A色谱柱,选择与铁形成单一络合形态、中等络合能力的2,6-吡啶二羧酸（PDCA）为淋洗液,在线柱后添加普适性的4-2-吡啶偶氮苯二酚（PAR）金属显色剂,于530 nm波长下准确完成了二价和三价铁离子的分离测定。结果表明,本方法对二价铁离子和三价铁离子的检出限分别为0.013 mg/kg和0.006 mg/kg,线性相关系数r²均大于0.999,实际样品中二价铁和三价铁的加标回收率分别为79%~90%和92%~105%,具有较高的灵敏度、准确度和选择性。该方法可以准确测定高纯硅微粉中痕量二价铁和三价铁的含量,以此结果反馈高纯硅微粉产品中铁杂质含量的不同来源,为其生产工艺的持续优化和改进提供重要的参考数据。     

不同羧酯比的聚马来酸十八醇酯齐聚物的镉盐LB膜成膜特性研究

由聚马来酸杆和十八醇合成了一系列不同羧酯比的聚马来酸十八醇酯（PMA），并以其为成膜材料、CdCl2水溶液为亚相制备了一系列聚马来酸十八醇酯镉盐（CdPMA）LB膜．借助小角X射线衍射和红外吸收光谱表征了成膜条件及羧酯比对CdPMA膜有序结构的影响．在较高膜压（30mN／m）和快速提拉（10cm／min）条件下，低羧酯比的CdPMA可得到有序性很高的Y-型LB多层膜；高羧酯比的CdPMA得不到高有序性的LB多层膜．