New progress in active immunotherapy targeting to amyloid beta

Alzheimer's disease(AD) is one of the most common types of dementia whose hallmarks include neurofibrillary tangles and senile plaques. The latter are mainly composed of amyloid-β proteins(Aβ), and it's suggested that Aβ may be the causative factor in AD pathogenesis. Immunotherapy targeting Aβ for preventing aggregation of Aβ and mildly clearing amyloid plaques has been a hot topic since 1999. Although the first clinical trial of Aβ vaccine, AN-1792, failed in phase II, its results suggested some key points in the design of Aβ vaccines. Avoiding the possible toxic Aβ specific T cell response and inducing a Th2 type cellular immune response may be beneficial for Aβ immunotherapy. Many associations and research groups are working on Aβ vaccine and some progress has been made in recent years. In this review, we have provided a detailed summary of past Aβ vaccines, which have been sorted by the immunogen, and we also discuss some recent progress and future perspectives.     

Direct synthesis of propylene carbonate from propylene and carbon dioxide catalyzed by quaternary ammonium heteropolyphosphatotungstate–TBAB system

In this paper,we have developed a highly efficient method for the direct preparation of propylene carbonate from propylene and carbon dioxide(CO2) using quaternary ammonium heteropolyphosphatotungstate–quaternary ammonium halide catalytic system with anhydrous hydrogen peroxide as an oxidant through one-pot two-step process.The effects of the amount of tetrabutylammonium bromide(TBAB),the concentration of hydrogen peroxide and other reaction conditions were investigated.The catalyst system gave an optimum propylene oxide yield(91%) at75°C in oxidation step and the highest propylene carbonate yield(99%) at 140°C and 3.0 MPa in cycloaddition step.Based on the results,a reaction mechanism has been proposed.     

直流射频等离子体增强化学气相沉积类金刚石碳薄膜的结构及摩擦学性能研究

利用直流射频等离子增强化学气相沉积技术在单晶硅表面制备了类金刚石碳薄膜．采用Raman光谱、红外光谱、x射线光电子能谱和原子力显微镜等研究了薄膜的微观结构和表面形貌,在UMT-2MT型摩擦磨损试验机上考察了薄膜在不同载荷与滑动速度下的摩擦学性能。结果表明：所制备的类金刚石碳薄膜具有典型的类金刚石结构特征,薄膜均匀、致密,表面粗糙度小,硬度较高;薄膜与Si3N4陶瓷球对摩时显示出良好的抗磨减摩性能;随着试验载荷与滑动速度的提高,薄膜的摩擦系数降低,耐磨寿命降低;薄膜的减摩抗磨性能同其在Si3N4陶瓷球偶件磨损表面形成的转移膜相关。     

THERMODYNAMIC AND PARTICLE-DYNAMIC STUDIES ON SYNTHESIS OF SILICA NANOPARTICLES USING MICROWAVE-INDUCED PLASMA CVD

1. Introduction1.1 Silica nanoparticles and synthesis methods Silica (SiO2) nanoparticles are widely used in industry asan active filler for polymer reinforcement, a rheologicaladditive in fluids, a free flow agent in powders, and anagent for chemical mechanical polishing during IC (inte-grated circuit) fabrication (Sniegowski & de Boer, 2000).Silica powder is also used for producing silicon carbide(Koc & Cattamanchi, 1998) or opaque silica aerosols (Leeet al., 1995). Many methods can …     

Activation free energy of Zn（Ⅱ）,Co（Ⅱ） binding to metallo-β-lactamase ImiS

In an effort to understand the recombination of a B2 metallo-β-lactamase（MβL）,the binding of metals to apo-ImiS was studied by isothermal titration calorimetry and fluorescence spectra.The binding of Zn（Ⅱ）,Co（Ⅱ） to apo-lmiS resulted in activation free energies △G_≠~θ values of 93.719 and 92.948 kJ mol~（-1）,respectively,and increasing of fluorescence intensity at maxima emission of 340 nm.     

Highly efficient regioselective ring openings of N-tosylaziridines to haloamines using ferric(Ⅲ) halides

FeX3（X = Cl, Br） were found to be very effective reagents and powerful catalysts for regioselective ring openings of a variety of N-tosylaziridines with them to afford the corresponding b-haloamines in good to excellent yields with high regioselectivity under mild conditions. At the same time, 13 new compounds were obtained firstly. Moreover, the b-bromoamine prepared could be transferred into b-nitroamine with NaNO2 in moderate yield.     

Silver(I)-mediated reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides:Unexpected formation of vinvl sulfones

A novel reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides was performed in the presence of silver nitrate or triflate.Conjugated vinyl sulfones as dramatic products were obtained in moderate yields and with Z-selectivity.A free radical mechanism has been proposed to account for the formation of the products.     

An expedient one-pot synthesis of highly substituted imidazoles using supported ionic liquid-like phase（SILLP） as a green and effcient catalyst and evaluation of their anti-microbial activity

An effcient method for the synthesis of imidazole derivatives by a three-component condensation of benzil or 9,10-phenanthrenequinone,aldehydes and ammonium acetate using supported ionic liquidlike phase（SILLP）catalyst under ultrasonic irradiation or classical heating conditions is reported.The present methodology offers several advantages,such as excellent yields,simple procedures,short reaction times,simple work-up and mild conditions.The catalyst is easily separated from the products by fltration and also exhibits remarkable reusable activity.These highly substituted imidazoles were also evaluated for their anti-microbial activity.     

基于物理课堂有效教学的策略浅析

根据有效教学的理念提出了课堂有效教学的基本策略、动力策略和长效策略,并结合基础物理的教学,对这些教学策略的科学掌握和运用进行了探讨.     

手性络合物[M(bpy)_2(phen)]~(2+)和[M(phen)_2(bpy)]~(2+)(M=Ru,Os)圆二色谱的理论解析

应用密度泛函理论,在B3LYP/LanL2DZ水平上对C2对称性的混配络合物[M(bpy)2(phen)]2+和[M(phen)2(bpy)]2+(M=Ru、Os;bpy=2,2'-bipyridine;phen=1,10-phenanthroline)在水溶液中的几何构型进行了优化,并用TDDFT/B3LYP方法和相同的基组计算了其激发能、旋转强度和振子强度,绘制了相应的圆二色谱(CD).在分析有关跃迁性质的基础上,对实验圆二色谱的谱带进行了明确的解析和指认,同时讨论了短波区激子裂分的规律性.结果表明:四种络合物在长波区(λ>320nm)的CD吸收带主要是由d-π*跃迁产生的荷移谱带;短波区(λ<320nm)则是配体上平行于长轴的π-π*跃迁产生的激子耦合带,且对于Λ构型表现为正的手性激子裂分.其中,[M(bpy)2(phen)]2+只显示出正负两个激子带,分属于联吡啶和邻菲咯啉配体;而[M(phen)2(bpy)]2+则有三个激子带,其中左侧的两个(一负一正)属于邻菲咯啉配体,右侧的正带则属于联吡啶配体.此外,尽管激子耦合属于远程相互作用,但用TDDFT计算的激子裂分样式仍是正确的.这些结论对于深入理解有...