Low-surface-free-energy polybenzoxazine/polyacrylonitrile fibers for biononfouling membrane

We blended poly(3-phenyl-3,4-dihydro-2H-1,3-benzoxazine) (PBA) into polyacrylonitrile (PAN) to generate low-surface-free-energy fibers without fluorine and silicon elements for electrospinning. Liquid-state BA at room temperature can be solidified in electrospinning process using PAN as a medium through their miscible behavior. Results indicate that the mixing below 50 wt% BA into PAN matrix for electrospinning has no significant dropping beads, indicated a miscible PAN/BA system. Above 70 wt% BA in PAN solution could not be solidified completely after electrospinning, revealed apparent beaded fibers. The PAN/PBA blend fibers, obtained after curing at 300 °C, generated a superhydrophobicity because of the low-surface-free-energy PBA. In addition, laser scanning confocal microscope (LSCM) measurements were included to determine the relative amount of antibody that adsorbed to these PAN/PBA fibers to examine the biofouling-resistant property. The results showed an obviously decreased protein adsorption with increasing PBA fraction. The correlations between PAN and PBA would provide insight into the designing and developing of low-surface-free-energy fibers without fluorine and silicon elements to improve biofouling-resistant property.     

Identification and Characterization of Buried Unpaired Cysteines in a Recombinant Monoclonal IgG1 Antibody

The heterogeneity in therapeutic antibodies arising from buried unpaired cysteines has not been well studied. This paper describes the characterization of two unpaired cysteines in a recombinant humanized IgG1 monoclonal antibody (referred to as mAb A). The reversed-phase high-performance liquid chromatography (RP-HPLC) analysis of mAb A samples showed three distinct peaks, indicating the presence of three species. The heterogeneities observed in the RP-HPLC have been determined to arise from unpaired cysteines (Cys-22 and Cys-96) that are buried in the V(H) domain. The Fab containing free thiols (referred to as "free-thiol Fab") and the Fab containing the disulfide (referred to as "intact Fab") of mAb A were generated through limited Lys-C digestion and purified with an ion exchange chromatography method. The binding of free-thiol Fab and intact Fab to its antigen was measured in a cell-based binding assay and an enzyme linked immunosorbent assay. The unpaired cysteines in the Fab of mAb A were found to have no significant impact on the binding to its target. Consistent with these Fab binding data, the enriched intact mAb A containing free thiols was determined to be fully active in a potency assay. The data reported here demonstrate that the redox status of cysteines is potentially a major source of heterogeneity for an antibody.     

Nanosized silica‐supported metallocene/MAO catalyst for propylene polymerization

A nanosized silica particle was used as the support to prepare an Et[Ind]₂ZrCl₂/MAO catalyst for propylene polymerization of polypropylene. The catalyst and the polymer produced were characterized with nitrogen adsorption, ICP, DSC, SEM, TEM, XRD, solution viscometer, ¹³C NMR and optical microscopy. The effects of polymerization temperature and [Al]/[Zr] ratio on catalyst activity and polymer melting point were investigated. Under identical reaction conditions, nanosized catalyst exhibited better polymerization activity than the microsized catalyst (e.g., the former had 64% higher activity than the latter at the optimum polymerization temperature (50°C) and [Al]/[Zr] = 570). DSC results indicated that polymer melting point increased with the increase of [Al]/[Zr] ratio and with the decrease of polymerization temperature. XRD results showed that the percentage of γ crystals increased with decreasing [Al]/[Zr] ratio. Electron microscopic results showed that the polymer particle size increased with increasing polymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2573–2580, 2006     

司盘-80对魔芋葡甘聚糖-玉米醇溶蛋白复合膜性能的影响

为了提高魔芋葡甘聚糖（KGM）和玉米醇溶蛋白（zein）的复合相容性,本文探讨了表面活性剂司盘-80对复合膜性质的影响。结果表明,适当的添加司盘-80可以有效提高KGM与zein的相容性,使复合膜更加光滑、致密,显著增强复合膜的热稳定性、疏水性、力学性能和阻氧性能,并降低水蒸气透过率。在最佳司盘-80添加量（2.5%,w/w）时,复合膜的拉伸强度和断裂伸长率最大（（63.02±0.67）MPa和15.97%±0.16%）,相比于未添加的复合膜分别显著提高25.5%和24.3%（p<0.05）,同时水蒸气透过率下降52.3%,膜的阻氧性能最大。本研究为KGM-zein复合膜在食品包装上的开发与应用提供一定参考价值。      

基于SEA的潜射反舰导弹作战效能分析

在考虑作战双方的对抗以及战场环境影响的情况下,运用系统有效性分析(System Effec- tiveness Analysis,SEA)方法,将潜射反舰导弹的系统属性、作战环境和任务使命三要素结合起来,建立了潜射反舰导弹的效能评估模型,给出了基于战场环境下的动态作战效能评估方法,避免了以往静态效能评估和动态评估的局限性,使作战效能评估结果更加接近真实情况,对潜射反舰导弹作战效能的提高有一定的指导意义。     

The oxidation behavior of an Fe61B15Zr8Mo7Co5Y2Cr2 bulk metallic glass at 650 °C in various oxygen-containing environments

The oxidation behavior of an Fe₆₁B₁₅Zr₈Mo₇Co₅Y₂Cr₂ bulk metallic glass (Fe7-BMG) was investigated in three oxygen-containing atmospheres over the oxygen partial pressure range of 10³–10⁵ Pa at 650 °C. The oxidation kinetics of the Fe7-BMG followed the parabolic rate law in all cases, indicating that solid-state diffusion is the rate-controlling step during oxidation. The oxidation rate constants (k_p values) increased with increasing oxygen partial pressure, implying a typical scaling behavior with a p-type semiconductivity. Duplex scales formed on the Fe7-BMG consisted of an outer layer of mostly iron oxides (Fe₂O₃/Fe₃O₄) and minor amounts of B₂O₃, and a heterophasic inner layer of mostly tetragonal-ZrO₂ (t-ZrO₂) intermixed with non-oxidized intermetallic phases.     

Time-Multiplexed Analog Transmission of Three Broadcast-Quality Television Channels Through One Satellite Transponder

This paper describes a TV signal compression scheme which may become a common practice for analog video transmission and broadcast via satellite by the year 2000. The technique uses twodimensional interfield processing to reduce the video bandwidth with minimum degradation in subjective quality, and time multiplexed with analog multiplexing technique for transmission in component format. Computer simulations of the processing technique on the test slides, and analysis of subjective quality andS/Nexpected over a typical satellite link, are reported. A proof-of-concept prototype being developed at COMSAT Laboratories is also outlined.     

Bounds for Throughput in Production/Inventory Systems in Series with Deterministic Processing Times

A production/inventory system consisting of work stations in series and a finished product warehouse is introduced. Bounds for the throughput are developed through the analysis of the reversed system of tandem queues. Examples are provided to show the bounds.     

Effects of Ni Additions on the Growth of Cu<Subscript>3</Subscript>Sn in High-Lead Solders

In reactions between solders and Cu, additions of minor alloying elements, such as Fe, Co or Ni, to solders often reduce the Cu₃Sn growth rate. Nevertheless, the mechanism for this effect remains unresolved. To provide more experimental observations that are essential for uncovering this mechanism, growth of Cu₃Sn in the reaction between Cu and high-lead solders with or without Ni additions has been studied. The solders used for this study were 10Sn-90Pb and 5Sn-95Pb doped with 0 wt.%, 0.03 wt.%, 0.06 wt.%, 0.1 wt.% or 0.2 wt.% Ni. Reaction conditions included one reflow at 350°C for 2 min and solid-state aging at 160°C for up to 2000 h. The effect of Ni on the growth of Cu₃Sn is discussed in detail based on the experimental results.