Characterization of the artificially covalent conjugate of B-phycoerythrin and R-phycocyanin and the phycobilisome from Porphyridium cruentum

B-phycoerythrin (BPE) and R-phycocyanin (RPC) were purified from Porphyridium cruentum by Sephadex G-200 chromatography, then the BPE was attached covalently to the RPC by reacting their amino groups to form the artificially covalent BPE-RPC conjugate in which the excitation energy can transfer from the BPE to the RPC with low efficiency. Meanwhile, the intact phycobilisome (PBS) consisting of BPE, RPC, APC and L-CM was isolated and purified from Porphyridium cruentum, and the purified PBS was found to keep intact if the solution contains sucrose. Comparison of spectroscopic properties between the purified PBS and the BPE-RPC conjugate suggests that the BPE-RPC conjugate is much more stable than the purified PBS. The construction of BPE-RPC conjugate with low efficiency of the excitation energy transfer may be useful for preparing phycobiliprotein probes. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Application of the Conjugate Gradient Optimization Algorithm of Neural Network on Laser Machining

在应用激光技术加工复杂曲面时,通常以采样点集为插值点来建立曲面函数,然后实现曲面上任意坐标点的精确定位。人工神经网络的BP算法能实现函数插值,但计算精度偏低,往往达不到插值精确要求,造成较大的加工误差。提出人工神经网络的共轭梯度最优化插值新算法,并通过实例仿真,证明了这种曲面精确定位方法的可行性,从而为激光加工的三维精确定位提供了一种良好解决方案。这种方法已经应用在实际中。

Conjugate Model for Heat and Mass Transfer of Porous Wall in the High Temperature Gas Flow

Heat and mass transfer of a porous permeable wall in a high temperature gas dynamical flow is considered. Numerical simulation is conducted on the ground of the conjugate mathematical model which includes filtration and heat transfer equations in a porous body and boundary layer equations on its surface. Such an approach enables one to take into account complex interaction between heat and mass transfer in the gasdynamical flow and in the structure subjected to this flow. The main attention is given to the impact of the intraporous heat transfer intensity on the transpiration cooling efficiency.

Measurement of small vibration amplitudes of a rough surface by an interferometer with a self-pumped phase-conjugate mirror

The application of a Michelson interferometer with a self-pumped phase-conjugate mirror to measure small vibration amplitudes of a rough surface is described. The distorted wave front of the light that is diffusely reflected from the rough surface is restored by phase conjugation to provide an interference signal with a high signal-to-noise ratio. The vibration amplitudes of a stainless-steel sample are measured with a precision of similar to 5 nm. (C) 2000 Optical Society of America OCIS codes: 120.3180, 190.5040, 120.7280.

Simultaneous determination of microcystin-LR and its glutathione conjugate in fish tissues by liquid chromatography-tandem mass spectrometry

A sensitive and selective liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantitative determination of microcystin-LR (MC-LR) and its glutathione conjugate (MC-LR-GSH) in fish tissues. The analytes were extracted from fish liver and kidney using 0.01 M EDTA-Na-2-5% acetic acid, followed by a solid-phase extraction (SPE) on Oasis HLB and silica cartridges. High-performance liquid chromatography (HPLC) with electrospray ionization mass spectrometry, operating in selected reaction monitoring (SRM) mode, was used to quantify MC-LR and its glutathione conjugate in fish liver and kidney. Recoveries of analytes were assessed at three concentrations (0.2, 1.0, and 5 mu g g(-1) dry weight [DW]) and ranged from 91 to 103% for MC-LR, and from 65.0 to 75.7% for MC-LR-GSH. The assay was linear within the range from 0.02 to 5.0 mu g g(-1) DW, with a limit of quantification (LOQ) of 0.02 mu g g(-1) DW. The limit of detection (LOD) of the method was 0.007 mu g g(-1) DW in both fish liver and kidney. The overall precision was determined on three different days. The values for within- and between-day precision in liver and kidney were within 15%. This method was applied to the identification and quantification of MC-LR and its glutathione conjugate in liver and kidney of fish with acute exposure of MC-LR. (c) 2007 Elsevier B.V. All rights reserved.

Real-time non-destructive testing of dynamic holograms in doubly-doped LiNbO3 crystals using phase-conjugate technique

Nankai University

Highly enantioselective conjugate addition of diethylzinc to acyclic enones with fine-tunable phosphite-pyridine ligands

A new series of fine-tunable phosphite-pyridine (P,N) ligands derived from (S)-2-amino-T-hydroxy-6,6'-dimethyl-1,1'-biphenyl and (S)-2-amino-2'-hydroxy-4,4',6,6'-tetramethyl-1,1'-biphenyl was employed in Cu(I)-catalyzed conjugate addition of diethylzinc to acyclic enones. Excellent enantioselectivities (up to 98% ee) and highly catalytic activities were achieved for a variety of acyclic enones.

Biodegradable amphiphilic polymer-drug conjugate micelles

The coupling of drugs to macromolecular carriers received an important impetus from Ringsdorf's notion of polymer-drug conjugates. Several water-soluble polymers, poly(ethylene glycol), poly[N-(2-hydroxypropyl) methacrylamidel, poly(L-glutamic acid) and dextran, are studied intensively and have been utilized successfully in clinical research. The promising results arising from clinical trials with polymer-drug conjugates (e.g., paclitaxel, doxorubicin, camptothecins) have provided a firm foundation for other synthetic polymers, especially biodegradable polymers, used as drug delivery vehicles. This review discusses biodegradable polymeric micelles as an alternative drug-conjugate system. Particular focus is on A-B or B-A-B type biodegradable amphiphilic block copolymer such as polylactide, morpholine-2,5-dione derivatives and cyclic carbonates, which can form a core-shell micellar structure, with the hydrophobic drug-binding segment forming the hydrophobic core and the hydrophilic segment as a hydrated outer shell. Polymeric micelles can be designed to avoid uptake by cells of reticuloendothelial system and thus enhance their blood lifetime via the enhanced permeability and retention effect.

Synthesis and characterization of the paclitaxel/MPEG-PLA block copolymer conjugate

A paclitaxel/MPEG-PLA block copolymer conjugate was prepared in three steps: (1) hydroxyl-terminated diblock copolymer of monomethoxy-poly(ethylene glycol)-b-poly(lactide) (MPEG-PLA) was synthesized by ring-opening polymerization of L-lactide using MPEG as a maroinitiator, (2) it was converted to carboxyl-terminated MPEG-PLA by reacting with mono-i-butyl ester of diglycolic acid and subsequent deprotecting the t-butyl group with TFA; (3) the latter was reacted with paclitaxel in the presence of dicyclohexylcarbodiimide and dimethylaminopyridine. Structures of the polymers synthesized were confirmed by H-1 NMR, and their molecular weights were determined by gel permeation chromatography. The antitumor activity of the conjugate against human liver cancer H7402 cells was evaluated by MTT method. The results showed that paclitaxel can be released from the conjugate without losing cytotoxicity.

一种新型阻性板室（RPC）探测器的研制

气体探测器在核物理及粒子物理领域有着广泛的应用，尤其是阻性板室探测器，以其低廉的造价、优异的性能在各个大型实验室中都发挥着重要的作用。日本国家高能物理实验室(KEK)的Belle探测器，斯坦福大学斯坦福直线加速器中心(SLAC)的BaBar大型探测器，欧洲核子中心(CERN)的大型强子对撞机(LHC)的CMS与ATLAS谱仪，北京高能物理研究所(IHEP)的BESⅢ谱仪都使用阻性板室作为触发系统或缪子探测器。 随着HIRFL-CSR项目的完工。RIBLL2开展高能放射性束物理实验成为可能，而为了鉴别高能重离子碰撞实验中出射的高能轻粒子，有必要测量粒子的飞行时间(TOF)。为此，我们研制了单隙定时RPC，并作了简单性能测试。在CSR实验终端上，它可以作为传统塑料闪烁晶体+PMT时间探测器的替代，成为反应出射产物测量的大型探测器系统(4π)中的重要成员。 本论文对RPC的发展历史以及被广泛应用的原因做了深入而详细的研究，并对RPC的结构、性能、工作模式、特点、气体系统等进行了深入探讨。研制了一套单气隙RPC探测器样机，测设了一些相关性能，并对所遇到问题的产生原因以及解决方案进行了分析。为了测试RPC的需要，搭建了一套多组分工作气体配气系统，论文中还对包括质量流量计的选定，相关配件的选择，以及后期整个配气系统的组装与调试进行了详细描述

Spectroscopic properties of the C-phycocyanin-allophycocyanin conjugate and the isolated phycobilisomes from Spirulina platensis

C-phycocyanin (CPC) and allophycocyanin (APC) were purified from Spirulina platensis, then the CPC was attached covalently to the APC by reacting their epsilon-amino groups. The excitation energy could be transferred from the CPC to the APC in the CPC-APC conjugate. Intact phycobilisomes (PBS), consisting of CPC, APC, colourless linker polypeptides, and APC B or L-cm, were isolated from S. platensis. Spectroscopic properties of the isolated PBSs kept at 20 degrees C for various times showed that the connection between the APC and the APC B or L-cm was looser than that between the CPC and the APC in the isolated PBSs. The CPC-APC conjugate was more stable than the isolated PBSs, and the linker polypeptides had a minor influence on the excitation energy transfer characteristic between different phycobiliproteins in the PBS.