Micro-Determination of Protein Containing SH– and –S–S– Groups Based on the Polarographic wave of an Electroactive Derivative

This paper presents a new simple and sensitive method for the micro-determination of protein containing SH– and –S–S– groups based on the single sweep polarographic wave of an electroactive derivative. In 0.04molL^–1 Na₃PO₄ and 0.2% ascorbic acid solution, protein is heated in a boiling water bath for 15min, the reaction product giving a sensitive reduction wave at –0.70V (vs. SCE). The wave height is linearly proportional to the concentration of protein. The calibration curves of bovine serum albumin (BSA), human serum albumin (HSA), ovalbumin (OVA) and lysozyme (Lyso) are constructed under the optimal conditions. For BSA and HSA, the linear ranges and detection limits are 0.05–24mgL^–1 and 0.02mgL^–1, respectively. The method has been applied to the determination of protein in human serum samples with satisfactory results. The mechanism of the polarographic wave was also studied, and the results show that S^2– ion is released from the protein molecule during the derivatization reaction, the wave being attributed to the reduction of HgS.     

Uncatalyzed Hydroamination of Electrophilic Organometallic Alkynes: Fundamental,Theoretical, and Applied Aspects

Simple reactions of the most used functional groups allowing two molecular fragments to link under mild, sustainable conditions are among the crucial tools of molecular chemistry with multiple applications in materials science, nanomedicine, and organic synthesis as already exemplified by peptide synthesis and “click” chemistry. We are concerned with redox organometallic compounds that can potentially be used as biosensors and redox catalysts and report an uncatalyzed reaction between primary and secondary amines with organometallic electrophilic alkynes that is free of side products and fully “green”. A strategy is first proposed to synthesize alkynyl organometallic precursors upon addition of electrophilic aromatic ligands of cationic complexes followed by endo hydride abstraction. Electrophilic alkynylated cyclopentadienyl or arene ligands of Fe, Ru, and Co complexes subsequently react with amines to yield trans‐enamines that are conjugated with the organometallic group. The difference in reactivities of the various complexes is rationalized from the two‐step reaction mechanism that was elucidated through DFT calculations. Applications are illustrated by the facile reaction of ethynylcobalticenium hexafluorophosphate with aminated silica nanoparticles. Spectroscopic, nonlinear‐optical and electrochemical data, as well as DFT and TDDFT calculations, indicate a strong push–pull conjugation in these cobalticenium– and Fe– and Ru–arene–enamine complexes due to planarity or near‐planarity between the organometallic and trans‐enamine groups involving fulvalene iminium and cyclohexadienylidene iminium mesomeric forms.     

基于扫描隧道显微镜的原子电子云结构

本文简要介绍了扫描隧道显微镜的基本工作原理，展示了一些扫描样品（石墨和铜）的电子云图，在简要介绍量子力学关于原子电子云结构基本理论的基础上，通过理论上的电子云结构与扫描结果的比较，在一定程度上验证了量子力学关于原子电子云结构理论的正确性．     

纳米科学技术及其在军事领域的应用展望

本文对作21世纪高新技术之一的纳米科学技术进行了阐述，并结合当前国内外的进展，就其在军用新材料技术，隐身技术，武器研制技术和军用电子技术等四个领域中在未来军事战争中的应用进行了阐述和展望。     

Enzymatic epoxidation of soybean oil in the presence of perbutyric acid

Enzymatic epoxidation of vegetable oils using a long chain fatty acid as an active oxygen carrier could produce a desirable epoxy oxygen group content (EOC); however, the acid value (AV) of final epoxidized oil is too high. The present study was to investigate the effect of different fatty acids with varying length of carbon chain on EOC and AV of the final epoxidized soybean oil (ESO); finding butyric acid was the choice of active oxygen carrier when hydrogen peroxide was used as an oxygen donor in the presence of lipase Novozyme 435. And in situ IR was used to monitor the epoxidation process, which revealed that the formation of perbutyric acid was the key step in the whole reaction. The epoxidation process was optimized as follows: molar ratio of butyric acid/C=C bonds of 0.19:1, 8% of immobilized lipase Novozyme 435 load (relative to the weight of soybean oil) and molar ratio of H₂O₂/C=C bonds of 3.5:1, reaction time of 4 h and reaction temperature of 45 °C. Under these conditions, ESO with a high EOC (7.62 ± 0.20%) and a lower AV value (8.53 ± 0.18 mgKOH/g) was obtained. The oxriane conversion degree was up to 97.94%.     

Asymmetric hydrogenation of simple ketones with planar chiral ruthenocenyl phosphinooxazoline ligands

Ruthenocenyl phosphinooxazoline ligands have been shown to be highly efficient catalysts in the asymmetric hydrogenation. Both simple aromatic and heteroaromatic ketones were examined and excellent conversions and enantioselectivities were achieved.     

CONVERGENCE ANALYSIS AND MRALLEL IMPLEMENTION FOR THE DIRECTEDGRAPH -ALGORITHM

1IntroductionAssulliingX=(xl.T?'....:ltnItR",iff(X):Rn~Rcanbeformedasfollows:whereOdenotesabinaryopertion(suchas ,x,tnax,minetc.),wecallf(X)aspearablefun.ti.n[1].L.Cooperstated'thatmostoffunctionsmaybetransformedtoseparableformsbyincreasingassistantvariablesandconstraints[2].InPracticalapplications,multistageproduction-inventoryproblems,equipmentreplacementproblems,resouceallocationproblemsandsomeschedulingproblemsetc.,canallbeformulatedasthefollowingforms[3].wherefi,hi(15jSn):R~R.Appara…     

Effect of polarization on efficiency of volume Bragg grating filter

<正>Diffraction efficiency of volume Bragg grating,whose period is in the same order as the incident wavelength, is related to the polarization direction of the incident linear polarized beam.When two linearly polarized recording beams with the same polarization direction are used for recording volume Bragg gratings in a photopolymer with diffusion amplification,the azimuth of polarization of the reconstruction beam influences the diffraction efficiency of the grating.When the probe beam is linearly polarized and oriented orthogonally to the grating vectors,the±1-order diffraction beams are also linearly polarized with polarization direction parallel to that of the probe beam.According to the results,a two-dimensional nonspatial optical filter consisting of the volume Bragg gratings would achieve significantly higher efficiency.     

Development of three novel benzothiazole-based ratiometric fluorescent chemosensor for detecting of hydrazine in serum and gas phase via ESIPT process and different recognition sites

In this article, we have successfully designed and synthesized three novel ratiometric fluorescent probes BTP-LA, BTP-LB and BTP-LN for detection of hydrazine based on benzothiazole-derived fluorophores and different recognition sites. The probes BTP-LA, BTP-LB and BTP-LN displays a good fluorescence ratio emission signals, high selectivity and large emission shifts (>100 nm) toward hydrazine. The three probes BTP-LA, BTP-LB and BTP-LN can be used not only to detect hydrazine in serum, but also to detect gaseous hydrazine in air. More importantly, compared with probes BTP-LB and BTP-LN, BTP-LA has lower saturation concentration (200 µM) and detection limits (1.22 × 10^?7 M) to hydrazine.