Purification and Characterization of a New Serine Protease with Fibrinolytic Activity from the Marine Invertebrate, Urechis unicinctus

A non-hemorrhagic, chymotrypsin-like serine protease, UFEII, was purified from the marine echiuroid worm, Urechis unicinctus, after a combination of chromatography steps. UFEII was monomeric, with an apparent molecular weight of 26.7 kDa via SDS-PAGE. The isoelectric point of UFEII was 4.03, and the maximum activity of the enzyme was observed at 50 °C and pH?8.0. According to fibrin plate assays, UFEII could not only directly degrade fibrin and fibrinogen but also activate plasminogen. Further, UFEII preferentially hydrolyzed the fibrinogen γ-chain, followed by the Bβ-chains and Aα-chains. Moreover, ufeII, full length of the gene encoding UFEII, was obtained by RT-PCR, degenerated PCR, and nested PCR. The ufeII was determined to be a 906-bp cDNA containing an open reading frame of 795 bp encoding a putative protein of 264 amino acids with a predicted molecular weight of 27.03 kDa. Besides, UFEII exhibited no hemorrhagic effect. Overall, U. unicinctus may represent a potential source of new therapeutic agents in thrombolytic therapy.     

Solubility of ethane int-butanol + water mixtures and a hydrophobic interaction study

The solubilities of ethane int-butanol (TBA) and water mixtures have been determined at 10, 15, and 20°C and pressures up to 3.1 MPa. Thermodynamic properties have also been calculated based on the measured solubility data and the hydrophobic interaction for the methane-methane pair interaction in the mixed solvent is discussed.     

GaAs1×4Mach－Zehnder型光开关列阵研究

采用非对称Ｘ结耦合器设计并研制了ＧａＡｓ１×４Ｍａｃｈ－Ｚｅｈｎｄｅｒ型光开关列阵。简述了非对称Ｘ结和相应的光开关列阵的工作原理及器件的设计和制作过程。在波长为１．１５μｍ的光波下测量单元器件，得到了小于－２０ｄＢ的串音和小于１２Ｖ的开关电压，器件的光波导传输损耗约为７ｄＢ／ｃｍ。文中最后分析了导致器件中串音和损耗的各因素，并提出了可能的改进方法     

ON THE STABILITY OF DIFFERENTIAL SYSTEMS WITH TIME LAG

In this paer the inequality of Lemma 1 of [1] is extended.By means of our inequality and the method of Lyapunov function we study the stability of two kinds of large seate differential systems with time lag and the stability of a higher -order differential equation with time lag.The sufficient conditions for the stability(S.),the asymptotic stability(A.S.),the uniformly asymptotic stability(U.A.S) and the exponential asymptotic stability(E.A.S.) of the zero solutions of the systerms are obtained respectively.     

Nitrogenases—A Tale of Carbon Atom(s)

Named after its ability to catalyze the reduction of nitrogen to ammonia, nitrogenase has a surprising rapport with carbon—both through the interstitial carbide that resides in the central cavity of its cofactor and through its ability to catalyze the reductive carbon–carbon coupling of small carbon compounds into hydrocarbon products. Recently, a radical‐SAM‐dependent pathway was revealed for the insertion of carbide, which signifies a novel biosynthetic route to complex bridged metalloclusters. Moreover, a sulfur‐displacement mechanism was proposed for the activation of carbon monoxide by nitrogenase, which suggests an essential role of the interstitial carbide in maintaining the stability while permitting a certain flexibility of the cofactor structure during substrate turnover.     

Decompaction of cationic gemini surfactant-induced DNA condensates by beta-cyclodextrin or anionic surfactant

Compaction of DNA by cationic gemini surfactant hexamethylene-1,6-bis-(dodecyldimethylammoniumbromide) (C12C6C12Br2) and the subsequent decompaction of the DNA-C12C6C12Br2 complexes by beta-cyclodextrin (beta-CD) or sodium dodecyl sulfate (SDS) have been studied by using zeta potential and particle size measurements, atomic force microscopy (AFM), isothermal titration microcalorimetry (ITC), and circular dichroism. The results show that C12C6C12Br2 can induce the collapse of DNA into densely packed bead-like structures with smaller size in an all-or-none manner, accompanied by the increase of zeta potential from highly negative values to highly positive values. In the decompaction of the DNA-C12C6C12Br2 complexes, beta-CD and SDS exhibit different behaviors. For beta-CD, the experimental results suggest that it can remove the outlayer hydrophobically bound C12C6C12Br2 molecules from the DNA-C12C6C12Br2 complexes by inclusion interaction, and the excess beta-CD may attach on the complexes by forming inclusion complexes with the hydrocarbon chains of the electrostatically bound C12C6C12Br2 that cannot be removed. The increase of steric hindrance due to the attachment of beta-CD molecules results in the decompaction of the DNA condensates though the true release of DNA cannot be attained. However, for SDS, the experimental results suggest that it can realize the decompaction and release of DNA from its complexes with C12C6C12Br2 due to both ion-pairing and hydrophobic interaction between SDS and C12C6C12Br2.     

Bilirubin Removal by Polymeric Adsorbents for Hyperbilirubinemia Therapy

Hyperbilirubinemia, presenting as jaundice, is a life-threatening critical illness in newborn babies and acute severe hepatic failure patients. Over the past few decades, extracorporeal hemoadsorption by adsorbent therapy has been widely applied in the treatment of hyperbilirubinemia. The capability of hemoadsorption depends on the adsorbents. Most of the clinically used bilirubin adsorbents are made up of styrene/divinylbenzene copolymer and quaternary ammonium salt, which usually have poor biocompatibility and weak mechanical strength. To overcome the drawbacks of commercial polymer adsorbents, advanced synthetic and natural polymers with/without nanomaterials have been designed, and novel adsorbent fabrication technologies have also been developed. In this review, the adsorption mechanism of bilirubin adsorbents has been summarized, which is the basic criterion in adsorbent development. Furthermore, the preparation method, adsorption mechanism, relative merits and practicability of the emerging bilirubin adsorbents have been evaluated. Based on the existing studies, this work highlights the future direction of the efforts on how to design and develop bilirubin adsorbents with good overall clinical performance. Perhaps this study can change traditional perspectives and propose new strategies for bilirubin clearance from the aspects of pathogenic mechanisms, metabolic pathways, and material-based innovation.     

Catalytic Asymmetric Hydrophosphinylation of 2-Vinylazaarenes to Access P-Chiral 2-Azaaryl-Ethylphosphine Oxides

A chiral Brønsted acid-catalysed asymmetric hydrophosphinylation of 2-vinylazaarenes by secondary phosphine oxides is described. A variety of P-chiral 2-azaaryl-ethylphosphine oxides are synthesized with high yields and ees, of which both the substituents of phosphines and azaarenes can be flexibly modulated, underscoring an exceptionally broad scope of substrates. These adducts are valuable to asymmetric metal catalysis since the resultant P-chiral tertiary phosphines from the reduction of them are verified as a kind of effective C₁-symmetric chiral 1,5-hybrid P,N-ligands. Importantly, this catalysis platform enables the generic and efficient kinetic resolution of P-chiral secondary phosphine oxides. It thus provides an expedient approach to access the enantiomers of the P-chiral tertiary phosphine oxides derived from asymmetric hydrophosphinylation, further improving the utility of the method.     

Surface patterns induced by Cu2+ ions on BPEI/PAA layer-by-layer assembly

The multilayer films of branched polyethyleneimine (BPEI) and poly(acrylic acid) (PAA) have been fabricated with the layer-by-layer (LbL) method. Two characteristic courses of the film thickness growth are observed, which are the initial exponential-like growth and the following linear growth. The variation of the COOH/COO- ratio indicates that the ionization degree of the polyelectrolyte molecules decreases at the initial stage of the multilayer buildup and then levels off after about eight bilayers. The as-prepared (BPEI/PAA)n films show a relatively smooth surface. However, great morphology changes occur after immersing these films in Cu2+ or Zn2+ solution. In the case of n > or =7, wavelike surface patterns are induced to form on the films. Both wavelength and fluctuation of these surface patterns show a systematical variation with an increase of the bilayer number. Moreover, thermal treatment can stabilize these patterns and enable the preservation of them after releasing the Cu2+ ions from the LbL films by acidic treatment. Interestingly, only Cu2+ and Zn2+ can induce the formation of such surface patterns, whereas Fe2+, Ca2+, Ag+, and Na+ cannot. This phenomenon may closely relate to the different natures of the metal ions.