PHOTODESTRUCTION OF BACTERIORHODOPSIN

Abstract— Suspensions of purple membrane fragments showed obvious signs of degradation after illumination with intense pulses of light from 10 ns frequency doubled Nd: YAG laser at 532 nm with intensity densities in excess of 1 MW/cm². Using controlled illumination, a small fraction of the bacteriorhodopsin protein molecules were randomly destroyed in samples with a low salt concentration (12.5 m M ) and pH = 7.9. Calculations using information from the changes in the optical absorbance spectrum and transient changes in the optical absorbance spectrum during the photocycle support a model where one protein molecule of the bacteriorhodopsin trimer is photodestroyed, the other two protein molecules switch to a blue state . In the blue state , the protein molecules have a red shifted absorption, with a peak near 600 nm. The blue state molecules show transient absorption changes at 656 nm that are similar to the native bacteriorhodopsin, except the O state is missing or altered. Additionally, the changes in curvature of the purple membrane fragments that occur during the photocycle of intact protein molecules are severely depressed. The addition of salts to the photodestroyed suspension can change the blue state molecules back to a state with an absorption maximum at 568 nm. The salt ions probably shield the other members of the trimer from the photodestroyed protein. In these reconstituted samples, the O state is observed at 656 nm; however, the membrane bending is not observed.     

Reliability of flexible electrically conductive adhesives

Based on our previous work about electrically conductive adhesives (ECAs), a flexibilizer named 1,3‐propanediol bis (4‐aminobenzoate) was used to fabricate flexible ECAs (FECAs). ECAs, FECAs, and electronic devices connected by them were carried out the hot and humid aging test under constant humidity level of 85% relative humidity at 85 °C for 600 h. After aging, the bulk resistance change of ECAs was about 26%, that of FECAs was a little higher, about 29%. The contact resistance change of devices connected by ECAs and FECAs was very great, about 450% and 410%, respectively. The bonding area at connection interface between colloids and devices had delamination, even cracks. The delamination of ECAs was calculated about 60%, the average shear strength of ECAs was reduced about 45%, and those of FECAs were about 50% and 30%, respectively, so FECAs had a higher bonding stability in hot and humid environment. Copyright © 2012 John Wiley & Sons, Ltd.     

Two-photon dual-channel fluorogenic probe for in situ imaging the mitochondrial H2S/viscosity in the brain of drosophila Parkinson’s disease model

H₂S is an essential gas signal molecule in cells, and viscosity is a key internal environmental parameter. Recent studies have shown that H₂S acts as a cytoarchitecture agent and gas transmitter in many tissues, e.g., as a regulator of neuroendocrine in the brain for mediating vascular tone in blood vessels. Mitochondrial viscosity is an important parameter for judging whether mitochondrial function is normal. It has been reported that oxidative stress and mitochondrial dysfunction are connected with Parkinson’s disease (PD), and the protective role of H₂S in PD models has been extensively demonstrated. Herein, Mito-HS, a new two-photon fluorescent probe was demonstrated to detect cross-talk between the two channels of mitochondrial viscosity and H₂S content. Moreover, this probe could detect the relative amount of and changes in mitochondrial H₂S in situ due to the reduced mitochondrial targeting ability after reaction with H₂S. The results show that H₂S in mitochondria is inversely related to viscosity. The PD model has a lower H₂S in mitochondria and a higher mitochondrial viscosity than did the normal. This result is important for our deep understanding of PD and its causes.     

薄壁件加工系统动态响应分析

薄壁件在铣削加工中容易产生共振或变形，直接影响加工稳定性及加工精度。采用主轴-刀具-工件整体铣削系统连续梁模型，系统研究在动态铣削力作用下，刀具端部与工件端部的动态响应之间的相互影响关系以及对整体系统动态响应影响较大的薄壁件尺寸。结果表明，工件横截面高度对系统共振的影响较为明显，当高度尺寸较小时，工件的低频共振会通过动态铣削力直接反映到刀具端部的振动频响上。工件横截面底边宽度尺寸的增大虽然对共振频率的改变不太明显，但会导致激发出来的刀具共振幅度出现明显降低。研究成果可以为薄壁件铣削加工系统的稳定性控制提供理论基础。     

Simultaneous determination of calycosin‐7‐O‐β‐d‐glucoside,calycosin, formononetin,astragaloside IV and schisandrin in rat plasma by LC‐MS/MS: application to a pharmacokinetic study after oral administration of Shenqi Wuwei chewable tablets

A rapid, sensitive and reliable high‐performance liquid chromatography–mass spectrometry (LC‐MS/MS) method was developed and validated for simultaneous quantification of the five main bioactive components, calycosin, calycosin‐7‐O‐β‐d ‐glucoside, formononetin, astragaloside IV and schisandrin in rat plasma after oral administration of Shenqi Wuwei chewable tablets. Plasma samples were extracted using solid‐phase extraction separated on a CEC₁₈ column and detected by MS with an electrospray ionization interface in multiple‐reaction monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r > 0.995. The method had a lower limit of quantitation of 0.1, 0.02, 0.1, 1 and 0.1 ng/mL for calycosin, calycosin‐7‐O‐β‐d ‐glucoside, formononetin, astragaloside IV and schisandrin, respectively. Intra‐ and inter‐day precisions (relative standard deviation) for all analytes ranged from 0.97 to 7.63% and from 3.45 to 10.89%, respectively. This method was successfully applied to the pharmacokinetic study of the five compounds in rats after oral administration of Shenqi Wuwei chewable tablets. Copyright © 2014 John Wiley & Sons, Ltd.     

3D Organic–Inorganic Perovskite Ferroelastic Materials with Two Ferroelastic Phases: [Et3P(CH2)2F][Mn(dca)3] and [Et3P(CH2)2Cl][Mn(dca)3]

Organic–inorganic hybrid perovskite-type multiferroics have attracted considerable research interest owing to their fundamental scientific significance and promising technological applications in sensors and multiple-state memories. The recent achievements with divalent metal dicyanamide compounds revealed such malleable frameworks as a unique platform for developing novel functional materials. Herein, two 3D organic–inorganic hybrid perovskites [Et₃P(CH₂)₂F][Mn(dca)₃] ( 1 ) and [Et₃P(CH₂)₂Cl][Mn(dca)₃] ( 2 ) (dca=dicyanamide, N(CN)₂⁻) are presented. Accompanying the sequential phase transitions, they display a broad range of intriguing physical properties, including above room temperature ferroelastic behavior, switchable dielectricity, and low-temperature antiferromagnetic ordering (T_c=2.4 K for both 1 and 2 ). It is also worth noting that the spontaneous strain value of 1 is far beyond that of 2 in the first ferroelastic phase, as a result of the precise halogen substitution. From the point view of molecular design, this work should inspire further exploration of multifunctional molecular materials with desirable properties.     

Synthesis of a highly active amino‐functionalized Fe3O4@SiO2/APTS/Ru magnetic nanocomposite catalyst for hydrogenation reactions

An amino‐functionalized silica‐coated Fe₃O₄ nanocomposite (Fe₃O₄@SiO₂/APTS) was synthesized. The Fe₃O₄@SiO₂ microspheres possessed a well‐defined core–shell structure, uniform sizes and high magnetization. An immobilized ruthenium nanoparticle catalyst (Fe₃O₄@SiO₂/APTS/Ru) was obtained after coordination and reduction of Ru³⁺ on the Fe₃O₄@SiO₂/APTS nanocomposite. The Ru nanoparticles were not only ultra‐small with nearly monodisperse sizes but also had strong affinity with the surface of Fe₃O₄@SiO₂/APTS. The obtained catalyst exhibited excellent catalytic performance for the hydrogenation of a variety of aromatic nitro compounds, even at room temperature. Moreover, Fe₃O₄@SiO₂/APTS/Ru was easily recovered using a magnetic field and directly reused for at least five cycles without significant loss of its activity.     

非线性科学中的对称性研究及其应用

自1990年宁波大学非线性科学课题组完成非线性系统对称性约化的第1个对称性专题研究以来, 宁波大学的非线性科学研究,特别是非线性系统的对称性研究成为一个特色, 引起了同行的广泛关注. 宁波大学非线性科学团队在对称性研究方面的主要进展有: 递推算子的因式化和逆递推算子及逆对称和逆可积梯队、形式级数对称法、非局域对称及其局域化、达布变换和非局域对称、条件对称和分离变量法、对称群直接法、群不变非线性系统分类、超对称和玻色化、留数对称、从对称性到达布变换、非局域对称的对称性约化和相容Riccati展开法、完备对称和可积性、大气和海洋系统中的对称性应用、离散对称和多地物理学、局域对称和非局域对称的对偶及可积系统的正梯队和负梯队的对偶等.