First‐principles calculation of electronic structure of V‐doped anatase TiO2

The energetic and electronic structures of V‐doped anatase TiO₂ have been investigated systematically by the GGA+U approach, including replacement of Ti by V in the absence and presence of oxygen vacancies and the presence of an interstitial site. It was found that V should exist as a V⁴⁺ ion in the replacement of Ti in the anatase lattice, the electron transitions of which to the conduction band from V 3d states are responsible for the experimentally observed visible light absorption. The influence of V dopant concentration on the electronic and magnetic properties is also discussed, such as the influence of the U value in systems containing oxygen vacancies and spin flip phenomena for interstitial V‐doping.     

Preparation of molecular imprinted polymer with quaternary ammonium groups as recognition sites for separation of pig cyclophilin 18 and bovine serum albumin

We introduce a new type of molecular imprinted polymer (MIP) with immobilized assistant recognition polymer chains (ARPCs) to create effective recognition sites. In this work, cloned pig cyclophilin 18 (pCyP18) and BSA were used as templates, respectively. The template protein was selectively assembled with ARPCs from the library which consists of numerous limited length polymer chains with randomly distributed recognition sites of the quaternary ammonium cationic groups and immobilizing sites. The assemblies of protein and ARPCs were adsorbed by macroporous microspheres and immobilized by cross‐linking polymerization. After removing the templates, the two kinds of synthesized MIPs were used to adsorb cloned pCyP18 and BSA from protein mixtures respectively and both showed high selectivity. It confirms that this new method is suitable to separate proteins of both low and high molecular weight. The extended experiment on adsorption of natural pCyP18 from cytosol shows that the obtained MIP using cloned protein as template can be used to enrich natural protein of low content.     

Formation Sites and Microscopic Conformation Study on the Konjac Glucomannan Molecular Helices

<正>In this work,the formation sites,helical parameters and hydrogen bond positions of Konjac glucomannan molecular helices were investigated using molecular dynamic simulation method.To our interest,the KGM chain is mainly composed by local left and right helix structures. The formation sites of KGM chain might locate at the chain-segments containing acetyl groups,and the left helix is the favorable conformation of KGM.Temperature-dependent molecule conformation study indicates that the right helix is dominant when the temperature is lower than 343 K,above which,however,the left helix is dominating(right helix disappears).In addition,intramolecular hydrogen bonds in the left helix can be found at the-OH groups on C(2),C(4)and C(6)of mannose residues;comparably,the intramolecular hydrogen bonds in the right helix can be mainly observed at the-OH groups on C(4)and C(6)of the mannose residues and C(3)of the glucose residues.In conclusion,molecular dynamic simulation is an efficient method for the microscopic conformation study of glucomannan molecular helices.     

In Vitro Study of Ketoprofen and Indapamide Used in Multidrug Therapy: 1H-NMR Analysis

ABSTRACT

Interaction of ketoprofen (KP, a nonsteroidal anti-inflammatory drug) and indapamide (IDP, a thiazide-related diuretic) with human serum albumin (HSA) in low-affinity binding sites (LAS) and competition between these medicines used in multidrug therapy have been studied by proton nuclear magnetic resonance (¹H-NMR) spectroscopy.

The analysis of chemical shifts, Δσ (ppm), of drug proton resonances and the values of the association constant, K_a [M^?1], were used to estimate the effect of IDP and KP on the KP–HSA and IDP–HSA complexes, respectively. The results showed the changes in the affinity of human serum albumin toward the drug with different mechanisms of action (KP and IDP) and the competition in the binding to HSA.     

Ab-initio approach to study hydrogen diffusion in 9Cr steels

We calculate the equilibrium energies and migration barriers of Fe, Cr and H interstitial defects in α-FeX(X=Cr)$\mathrm{\alpha }\mathrm{-}\mathrm{FeX}(\mathrm{X}=\mathrm{Cr})$. We use the ab-initio electronic structure code, SIESTA, coupled to the monomer method to find activated states (or migration barriers), in order to study atomic defects diffusion. Ab-initio calculations reveal that in the presence of Cr the H migration barriers are higher than in pure α-Fe$\mathrm{\alpha }\mathrm{-}\mathrm{Fe}$. On the other hand, our permeation tests on 9%Cr–91%Fe alloys reveal a permeation coefficient 10 times lower and a diffusion coefficient 200 times lower than in pure, annealed iron. Focusing on our experimental results, we explore very simple model of new H trapping sites and possible migration paths that can explain the experimental observations.     

SOME FACTORS AFFECTING [~3H]TYROSINE BINDING TO PLASMA MEMBRANE PREPARATION OF RAT CORPORA LUTEA in vitro

Temperature, pH, enzymes and ions affected the two types of [~3H]tyrosine binding sites differently. The optimal temperature and pH for the high affinity sites were 24 C and 7.4, and for the low affinity sites 37℃ and 7.0, respectively. The [~3H]tyrosine binding to the high and low affinity sites was not observed at 55℃, nor at pH 6.0 or pH 8.5. Trypsin reduced [~3H]tyrosine binding to the high affinity sites, but had no effect on the binding to the low affinity sites. Neuraminidase reduced [~3H]tyrosine binding to the low affinity sites, but had no effect on the binding to the high affinity sites. None of cycloheximide, kCG, cAMP, and progesterone affected [~3H]tyrosine binding.     

Synthesis and crystal structure of a new oxychalcogenide La5Ti∼3.25Zr∼0.25S5O9.25

A new phase in the quinary system La/Ti/Zr/S/O was obtained from a mixture of La₂O₃, La₂S₃, ZrO₂, and TiO₂ by a solid-state reaction at 1273 K in a sealed fused-silica tube. The structure of this new phase, La₅Ti_∼3.25Zr_∼0.25S₅O_9.25, was solved by single-crystal X-ray diffraction, with R_(obs)=3.37% for 2764 reflections (I>3σ(I)) and 125 variables. This compound crystallizes with four formula units in the monoclinic space group C2/m with lattice constants , , , and β=106.100(8)°. The structure can be viewed as a 2D building constituted from two-atom-thick slabs of rock salt type (=sulfide part) which are interleaved with double-octahedral chains centered on titanium/zirconium atoms (mixed Ti/Zr sites) and drawing a zigzag arrangement (=oxide part). In addition, EDXS analyses show that a solid solution Ti/Zr exists with a general formulation La₅Ti_3.5−xZr_xS₅O_9.25 (where 0.1?x?0.5).     

线式和桥式中心上一氧化碳和氢相互作用研究

本文利用TP(程序升温)-IR动态方法研究了3%Rh_2/Al_2O_3的CO吸附,CO和H_2共吸附的动态行为.结果表明3%Rh_2/Al_2O_3上有孪生,线式和桥式三种吸附方式.当CO单独暴露于催化剂时,三种吸附中心上CO歧化在260℃以上发生.CO和H_2在室温下共吸附,在2050,1995和1815cm~(-1)出现谱带.可分别归属为Rh~1中心上的羰基氢化为(?),线式中心上的羰基氢化物(?)和桥式中心上的羰基氢化物(?).动态过程中这些羰基氢化物谱带向低频位移的行为也可归结为相应的多氢羰基氢化物的形成.与CO单独吸附的行为相比较,作者解释为在CO+H_2反应条件下,Rh_2/Al_2O_3的三种吸附中心上C-O键的削弱和断裂是经由相应的羰基氢化物-多氢羰基氢化物途径,而不是经由C-O键的直接断裂途径(CO解离或Bouduard反应).