Recent advances in asymmetric reactions catalyzed by chiral phosphoric acids

The very recent advances in chiral phosphoric acids (CPAs) catalyzed asymmetric reactions are discussed.     

Boron group element doping of Li1.5Al0.5Ge1.5(PO4)3 based on microwave sintering

Journal of Solid State Electrochemistry - We report effectiveness of dopants selected from group 13, such as B, Ga, and In, on the conductivity of Li1.5Al0.5Ge1.5(PO4)3 (LAGP) that is recognized as...     

Global Regularity of 3D Nonhomogeneous Incompressible Micropolar Fluids

This paper is concerned with the global well-posedness of strong and classical solutions for the 3D nonhomogeneous incompressible micropolar equations with vacuum. We prove that the problem (1.1)–(1.5) has a unique global strong/classical solution \((\rho,u,w)\), provided \(\mu_{1}\) is sufficiently large, or \(\|\rho_{0}\|_{L^{\infty}}\) or \(\|\rho_{0}^{1/2}u_{0}\| ^{2}_{L^{2}}+\|\rho_{0}^{1/2}w_{0}\|^{2}_{L^{2}}\) is small enough.

     

Analytic approximation of the blow‐up time for nonlinear differential equations by the ADM–Padé technique

We present a new approach to calculate analytic approximations of blow‐up solutions and their critical blow‐up times. Our approach applies the Adomian decomposition–Padé method to quickly and easily compute the critical blow‐up times, which comprises the Adomian decomposition method combined with the Padé approximants technique. We validate our new approach with a variety of numerical examples, including nonlinear ODEs, systems of nonlinear ODEs, and nonlinear PDEs. Furthermore, our new method is shown to be more convenient than prior art that relies on compound discretized algorithms. Copyright © 2013 John Wiley & Sons, Ltd.     

Predicting Polymorphism of Electrospun Polyvinylidene Fluoride Membranes by Their Morphologies

Although electrospinning of polyvinylidene fluoride (PVDF) has been studied for more than 10 years, the crystalline phase differentiation of the electrospun mats is still normally through the combination of different characterization techniques, and the relationship between polymorphism and morphology of the fibers in electrospun PVDF membranes has never been reported. Here, we show their close relationships by conducting room-temperature electrospinning experiments on various polymer/solvent systems. The electrospun membranes full of bead-free fibers have a very high fraction of β-phase, F(β), over 90%, and high orientation, whereas the membranes comprising beads and/or a large number of beaded fibers most often result in a low fraction of β-phase (F(β) normally below 50%) and low orientation. On the other hand, electrospun membranes consisting of both bead-free fibers and a very limited number of beaded fibers showed a medium high fraction of β-phase, F(β) more than 70% but less than 90%. These findings suggest the feasibility of intuitively predicting the crystalline phase of electrospun PVDF membranes directly by their morphologies, which is obviously simple, inexpensive and convenient for future investigations.     

Bioinformatics analysis of a non-specific nuclease from Yersinia enterocolitica subsp. palearctica

In this paper, the physical and chemical characteristics, biological structure and function of a non-specific nuclease from Yersinia enterocolitica subsp. palearctica (Y. NSN) found in our group were studied using multiple bioinformatics approaches. The results showed that Y. NSN had 283 amino acids, a weight of 30,692.5 ku and a certain hydrophilic property. Y. NSN had a signal peptide, no transmembrane domains and disulphide bonds. Cleavage site in Y. NSN was between pos. 23 and 24. The prediction result of the secondary structure showed Y. NSN was a coil structure-based protein. The ratio of α-helix, β-folded and random coil were 18.73%, 16.96% and 64.31%, respectively. Active sites were pos. 124, 125, 127, 157, 165 and 169. Mg²⁺ binding site was pos. 157. Substrate binding sites were pos. 124, 125 and 169. The analysis of multisequencing alignment and phylogenetic tree indicated that Y. NSN shared high similarity with the nuclease from Y. enterocolitica subsp. enterocolitica 8081. The enzyme activity results showed that Y. NSN was a nuclease with good thermostability.     

可逆Diels-Alder反应

通过高效的反应精确合成功能分子已成为现代化学发展的趋势之一。基于呋喃/马来酰亚胺(MI)之间的Diels-Alder(D-A)反应作为一种高效的和高选择性的点击反应,克服了铜催化的叠氮/炔之间的1,3-偶极环化加成(CuAAC)反应中引起的金属污染等缺点,为生物医药载体、功能性材料的制备提供更可行的途径。同时,呋喃/MI之间的D-A反应具备原料易得、反应条件温和及易发生retro D-A(rD-A)反应等优点,在制备响应性材料领域备受关注。本文综述了近年基于呋喃/MI的可逆D-A反应在响应性聚合物合成、智能材料、生物分子及表面修饰等方面的应用,并展望了D-A反应的发展前景。     

“点击”反应在制备环状聚合物中的应用

环状聚合物具有不同于线性高分子的独特性质,是一类具有应用前景的新型聚合物材料,但复杂的结构导致其合成过程复杂繁琐.＂点击＂化学由于其高效、可靠、高选择性的特点已成为拓扑高分子合成的新方法,活性自由基聚合（ATRP、RAFT和NMP）具有聚合物结构可控等特点,二者联用为环状聚合物的合成拓宽了思路.本文就近几年＂点击＂反应、＂点击＂反应与活性自由基聚合联用以及其他方法联用在环状聚合物中的应用进行综述.＂点击＂反应与这些方法的结合将在功能性环状聚合物的设计与合成中发挥积极的作用.