Highly Cooperative Tetrametallic Ruthenium-mu-Oxo-mu-Hydroxo Catalyst for the Alcohol Oxidation Reaction

The tetrametallic ruthenium-oxo-hydroxo-hydride complex {[(PCy(3))(CO)RuH](4)(mu(4)-O)(mu(3)-OH)(mu(2)-OH)} (1) was synthesized in two steps from the monomeric complex (PCy(3))(CO)RuHCl (2). The tetrameric complex 1 was found to be a highly effective catalyst for the transfer dehydrogenation of alcohols. Complex 1 showed a different catalytic activity pattern towards primary and secondary benzyl alcohols, as indicated by the Hammett correlation for the oxidation reaction of p-X-C(6)H(4)CH(2)OH (rho = -0.45) and p-X-C(6)H(4)CH(OH)CH(3) (rho = +0.22) (X = OMe, CH(3), H, Cl, CF(3)). Both a sigmoidal curve from the plot of initial rate vs [PhCH(OH)CH(3)] (K(0.5) = 0.34 M; Hill coefficient, n = 4.2+/-0.1) and the phosphine inhibition kinetics revealed the highly cooperative nature of the complex for the oxidation of secondary alcohols.     

坐而论道→实践教学→应用型人才

<正>中国的传统教育方式长久地印在教科书里,也成就了许多历史名人。在大多数人的观念里,出人头地、光耀门庭,就必须苦学苦读,以便考取功名,求得一官半职。于是头悬梁锥刺股、凿壁借光、囊萤映雪。夸一个人有才,必是:文章写得好,规范八股;字写得漂亮,有体有型。用现代教育的框架来形容,应该算是理论型人才,属于坐而论道者。     

Collagen and its rational content in meat products: Part 1. Analytical studies

Computer-assisted simulation has been used to study the effect of collagen content on the biological value of meat proteins. It has been shown that an increase in the collagen content from 2·5% to 15-20% of the total amount of proteins contained in minced meat tangibly enhances protein utilization for tissue synthesis. Hence, the above collagen content in meat products heightens their nutritional and biological value and renders them more suited for human metabolism.     

Interactions between immunoglobulin-like and catalytic modules in Clostridium thermocellum cellulosomal cellobiohydrolase CbhA

Cellobiohydrolase CbhA from Clostridium thermocellum cellulosome is a multi-modular protein composed starting from the N-terminus of a carbohydrate-binding module (CBM) of family 4, an immunoglobulin(Ig)-like module, a catalytic module of family 9 glycoside hydrolases (GH9), X1(1) and X1(2) modules, a CBM of family 3 and a dockerin module. Deletion of the Ig-like module from the Ig-GH9 construct results in complete inactivation of the GH9 module. The crystal structure of the Ig-GH9 module pair reveals the existence of an extensive module interface composed of over 40 amino acid residues of both modules and maintained through a large number of hydrophilic and hydrophobic interactions. To investigate the importance of these interactions between the two modules, we compared the secondary and tertiary structures and thermostabilities of the individual Ig-like and GH9 modules and the Ig-GH9 module pair using both circular dichroism (CD) spectroscopy and differential scanning calorimetry (DSC). Thr230, Asp262 and Asp264 of the Ig-like module are located in the module interface of the Ig-GH9 module pair and are suggested to be important in 'communication' between the modules. These residues were mutated to alanyl residues. The structure, stability and catalytic properties of the native Ig-GH9 and its D264A and T230A/D262A mutants were compared. The results indicate that despite being able to fold relatively independently, the Ig-like and GH9 modules interact and these interactions affect the final fold and stability of each module. Mutations of one or two amino acid residues lead to destabilization and change of the mechanism of thermal unfolding of the polypeptides. The enzymatic properties of native Ig-GH9, D264A and T230A/D262A mutants are similar. The results indicate that inactivation of the GH9 module occurs as a result of multiple structural disturbances finally affecting the topology of the catalytic center.     

第二届全国高等院校计算机核心技能与信息素养大赛圆满落幕

<正>由全国高等学校计算机基础教育研究会、教育部高等学校计算机基础课程教学指导委员会、《计算机教育》杂志社等八家单位共同主办,中国铁道出版社承办的"第二届全国高等院校计算机核心技能与信息素养大赛"(以下简称"大赛")于2012年成功举办,本届大赛共有来自全国202所高等院校的11781名大学生参加了预赛,通过角逐,168所院校的668位选手参加了总决赛。为推进大学计算机     

走新型工业化道路 培养新一代产业大军

<正>2008年的金秋季节,我们迎来了"第四届全国计算机教育论坛"。来自国际国内的计算机教育专家、学者、教育工作者相聚在福州大学,共同探讨计算机教育领域中的热点和前沿问题,激起了智慧的火花,引起了热烈的反响。     

前进中的国家示范性高等职业院校建设(一)——记天津职业大学的改革成果

<正>2006年11月,"国家示范性高等职业院校建设计划"正式启动,至今已有两年多。108所示范性高等职业院校开拓进取,锐意创新,进行大刀阔斧的改革,尝试着从各个方面开展工学结合的教育教学改革,包括人才培养模式、课程体系、课程     

站在高端,指点江山——“院长论坛”开栏语

<正>"全国高校计算机系主任论坛"是由北京航空航天大学、北京大学、国防科技大学、哈尔滨工业大学、南京大学、清华大学和浙江大学七所大学联合发起成立的。论坛自1998年以来,共举办了十一届,承办单位依次为北京航空航天大学(1998年、2006年)、国防科技大学(1999年)、哈尔滨工业大学(2000年)、浙     

Tribological assessment of a flexible carbon-fibre-reinforced poly(ether-ether-ketone) acetabular cup articulating against an alumina femoral head

New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of large-diameter carbon-fibre-reinforced pitch-based poly(ether-ether-ketone) (CFR-PEEK) acetabular cups articulating against alumina femoral heads. The joints were tested for 25 x 10(6) cycles. Friction tests were also performed on these joints to determine the lubrication regime under which they operate. The average volumetric wear rate of the CFR-PEEK acetabular component of 54 mm diameter was 1.16 mm(3)/10(6) cycles, compared with 38.6 mm(3)/10(6) cycles for an ultra-high-molecular-weight polyethylene acetabular component of 28 mm diameter worn against a ceramic head. This extremely low wear rate was sustained over 25 x 10(6) cycles (the equivalent of up to approximately 25 years in vivo). The frictional studies showed that the joints worked under the mixed-boundary lubrication regime. The low wear produced by these joints showed that this novel joint couple offers low wear rates and therefore may be an alternative material choice for the reduction of osteolysis.