Stress-Induced Domain Wall Motion in a Ferroelastic Mn3+ Spin Crossover Complex

Domain wall motion is detected for the first time during the transition to a ferroelastic and spin state ordered phase of a spin crossover complex. Single-crystal X-ray diffraction and resonant ultrasound spectroscopy (RUS) revealed two distinct symmetry-breaking phase transitions in the mononuclear Mn³⁺ compound [Mn(3,5-diBr-sal₂(323))]BPh₄, 1. The first at 250 K, involves the space group change Cc→Pc and is thermodynamically continuous, while the second, Pc→P1 at 85 K, is discontinuous and related to spin crossover and spin state ordering. Stress-induced domain wall mobility was interpreted on the basis of a steep increase in acoustic loss immediately below the the Pc-P1 transition     

Cross-Module Enoylreduction in the Azalomycin F Polyketide Synthase

The colinearity of canonical modular polyketide synthases, which creates a direct link between multienzyme structure and the chemical structure of the biosynthetic end-product, has become a cornerstone of knowledge-based genome mining. Herein, we report genetic and enzymatic evidence for the remarkable role of an enoylreductase in the polyketide synthase for azalomycin F biosynthesis. This internal enoylreductase domain, previously identified as acting only in the second of two chain extension cycles on an initial iterative module, is shown to also catalyze enoylreduction in trans within the next module. The mechanism for this rare deviation from colinearity appears to involve direct cross-modular interaction of the reductase with the longer acyl chain, rather than back transfer of the substrate into the iterative module, suggesting an additional and surprising plasticity in natural PKS assembly-line catalysis.     

Discovery of Cell‐Permeable Inhibitors That Target the BRCT Domain of BRCA1 Protein by Using a Small‐Molecule Microarray

BRCTs are phosphoserine‐binding domains found in proteins involved in DNA repair, DNA damage response and cell cycle regulation. BRCA1 is a BRCT domain‐containing, tumor‐suppressing protein expressed in the cells of breast and other human tissues. Mutations in BRCA1 have been found in ca. 50 % of hereditary breast cancers. Cell‐permeable, small‐molecule BRCA1 inhibitors are promising anticancer agents, but are not available currently. Herein, with the assist of microarray‐based platforms, we have discovered the first cell‐permeable protein–protein interaction (PPI) inhibitors against BRCA1. By targeting the (BRCT)₂ domain, we showed compound 15 a and its prodrug 15 b inhibited BRCA1 activities in tumor cells, sensitized these cells to ionizing radiation‐induced apoptosis, and showed synergistic inhibitory effect when used in combination with Olaparib (a small‐molecule inhibitor of poly‐ADP‐ribose polymerase) and Etoposide (a small‐molecule inhibitor of topoisomerase II). Unlike previously reported peptide‐based PPI inhibitors of BRCA1, our compounds are small‐molecule‐like and could be directly administered to tumor cells, thus making them useful for future studies of BRCA1/PARP‐related pathways in DNA damage and repair response, and in cancer therapy.     

基于小波域马尔可夫随机场模型的压缩传感图像重构

目前在压缩传感重构算法中利用图像的可稀疏性表示先验知识,从比奈奎斯特采样少得多的观测值中恢复原始图像。除了稀疏性之外,邻域系数的相关性也可以作为先验知识加速重构算法收敛。为了克服目前算法中没有利用邻域系数相关性的缺点,提出了基于小波域马尔可夫随机场模型的压缩传感图像重构算法,根据显著性度量对变换系数进行分类得到具有马尔可夫性的初始掩模,利用ICM算法完成掩模优化,实现系数更新,并将算法与未考虑邻域相关性的算法进行了比较。实验结果证明了算法的有效性。     

Electromechanical cracking in ferroelectrics driven by large scale domain switching

Experimental results indicate three regimes for cracking in a ferroelectric double cantilever beam (DCB) under combined electromechanical loading. In the loading, the maximum amplitude of the applied electric field reaches almost twice the coercive field of ferroelectrics. Thus, the model of small scale domain switching is not applicable any more, which is dictated only by the singular term of the crack tip field. In the DCB test, a large or global scale domain switching takes place instead, which is driven...     

关于亚纯函数增长级的一个注记

研究了无穷级亚纯函数f与亚纯函数g在某个角域上具有分担集S = {a1,a2,a3}的增长级关系.     

Multilinear Calderón Zygmund operators on variable exponent Morrey spaces over domains

The boundedness of multilinear singular integrals of Calderón-Zygmund type on product of variable exponent Lebesgue spaces over both bounded and unbounded domains are obtained. Further more, the boundedness for this type multilinear operators on product of variable exponent Morrey spaces over domains is shown in the paper.     

Parallel characteristic finite element method for time‐dependent convection–diffusion problem

Based on the overlapping‐domain decomposition and parallel subspace correction method, a new parallel algorithm is established for solving time‐dependent convection–diffusion problem with characteristic finite element scheme. The algorithm is fully parallel. We analyze the convergence of this algorithm, and study the dependence of the convergent rate on the spacial mesh size, time increment, iteration times and sub‐domains overlapping degree. Both theoretical analysis and numerical results suggest that only one or two iterations are needed to reach to optimal accuracy at each time step. Copyright © 2010 John Wiley & Sons, Ltd.     

An optimization‐based domain decomposition method for numerical simulation of the incompressible Navier‐Stokes flows

This article is concerned about an optimization‐based domain decomposition method for numerical simulation of the incompressible Navier‐Stokes flows. Using the method, an classical domain decomposition problem is transformed into a constrained minimization problem for which the objective functional is chosen to measure the jump in the dependent variables across the common interfaces between subdomains. The Lagrange multiplier rule is used to transform the constrained optimization problem into an unconstrained one and that rule is applied to derive an optimality system from which optimal solutions may be obtained. The optimality system is also derived using “sensitivity” derivatives instead of the Lagrange multiplier rule. We consider a gradient‐type approach to the solution of domain decomposition problem. The results of some numerical experiments are presented to demonstrate the feasibility and applicability of the algorithm developed in this article. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011     

Analysis of segregated boundary‐domain integral equations for variable‐coefficient problems with cracks

Segregated direct boundary‐domain integral equation (BDIE) systems associated with mixed, Dirichlet and Neumann boundary value problems (BVPs) for a scalar “Laplace” PDE with variable coefficient are formulated and analyzed for domains with interior cuts (cracks). The main results established in the paper are the BDIE equivalence to the original BVPs and invertibility of the BDIE operators in the corresponding Sobolev spaces. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010