Electrospun fiber membranes from blends of poly(vinylidene fluoride) with fouling‐resistant zwitterionic copolymers

Nonwoven super‐hydrophobic fiber membranes have potential applications in oil–water separation and membrane distillation, but fouling negatively impacts both applications. Membranes were prepared from blends comprising poly(vinylidene fluoride) (PVDF) and random zwitterionic copolymers of poly(methyl methacrylate) (PMMA) with sulfobetaine methacrylate (SBMA) or with sulfobetaine‐2‐vinylpyridine (SB2VP). PVDF imparts mechanical strength to the membrane, while the copolymers enhance fouling resistance. Blend composition was varied by controlling the PVDF‐to‐copolymer ratio. Nonwoven fiber membranes were obtained by electrospinning solutions of PVDF and the copolymers in a mixed solvent of N,N‐dimethylacetamide and acetone. The PVDF crystal phases and crystallinities of the blends were studied using wide‐angle X‐ray diffraction and differential scanning calorimetry (DSC). PVDF crystallized preferentially into its polar β‐phase, though its degree of crystallinity was reduced with increased addition of the random copolymers. Thermogravimetry (TG) showed that the degradation temperatures varied systematically with blend composition. PVDF blends with either copolymer showed significant increase of fouling resistance. Membranes prepared from blends containing 10% P(MMA‐ran‐SB2VP) had the highest fouling resistance, with a fivefold decrease in protein adsorption on the surface, compared to homopolymer PVDF. They also exhibited higher pure water flux, and better oil removal in oil–water separation experiments. © 2018 Society of Chemical Industry     

EGFR-Binding Peptides: From Computational Design towards Tumor-Targeting of Adeno-Associated Virus Capsids

The epidermal growth factor receptor (EGFR) plays a central role in the progression of many solid tumors. We used this validated target to analyze the de novo design of EGFR-binding peptides and their application for the delivery of complex payloads via rational design of a viral vector. Peptides were computationally designed to interact with the EGFR dimerization interface. Two new peptides and a reference (EDA peptide) were chemically synthesized, and their binding ability characterized. Presentation of these peptides in each of the 60 capsid proteins of recombinant adeno-associated viruses (rAAV) via a genetic based loop insertion enabled targeting of EGFR overexpressing tumor cell lines. Furthermore, tissue distribution and tumor xenograft specificity were analyzed with systemic injection in chicken egg chorioallantoic membrane (CAM) assays. Complex correlations between the targeting of the synthetic peptides and the viral vectors to cells and in ovo were observed. Overall, these data demonstrate the potential of computational design in combination with rational capsid modification for viral vector targeting opening new avenues for viral vector delivery and specifically suicide gene therapy.     

Polymer brush coatings for combating marine biofouling

A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies.     

横河DCS在连续PET生产中应用

介绍了YOKOGAWA公司的CENTUM VP在连续PET生产中的应用情况,以某一具体连续PET项目为例简述了控制系统硬件软件配置,以及具体的硬件软件组态过程,其中重点以酯化釜流程为例介绍了复杂控制方案的组态。     

Optimizing use of the structural chemical analyser (variable pressure FESEM‐EDX raman spectroscopy) on micro‐size complex historical paintings characterization

The novel Structural Chemical Analyser (hyphenated Raman spectroscopy and scanning electron microscopy equipped with an X‐ray detector) is gaining popularity since it allows 3‐D morphological studies and elemental, molecular, structural and electronic analyses of a single complex micro‐sized sample without transfer between instruments. However, its full potential remains unexploited in painting heritage where simultaneous identification of inorganic and organic materials in paintings is critically yet unresolved. Despite benefits and drawbacks shown in literature, new challenges have to be faced analysing multifaceted paint specimens. SEM?Structural Chemical Analyser systems differ since they are fabricated ad hoc by request. As configuration influences the procedure to optimize analyses, likewise analytical protocols have to be designed ad hoc. This paper deals with the optimization of the analytical procedure of a Variable Pressure Field Emission scanning electron microscopy equipped with an X‐ray detector Raman spectroscopy system to analyse historical paint samples. We address essential parameters, technical challenges and limitations raised from analysing paint stratigraphies, archaeological samples and loose pigments. We show that accurate data interpretation requires comprehensive knowledge of factors affecting Raman spectra. We tackled: (i) the in‐FESEM?Raman spectroscopy analytical sequence, (ii) correlations between FESEM and Structural Chemical Analyser/laser analytical position, (iii) Raman signal intensity under different VP‐FESEM vacuum modes, (iv) carbon deposition on samples under FESEM low‐vacuum mode, (v) crystal nature and morphology, (vi) depth of focus and (vii) surface‐enhanced Raman scattering effect. We recommend careful planning of analysis strategies prior to research which, although time consuming, guarantees reliable results. The ultimate goal of this paper is to help to guide future users of a FESEM‐Structural Chemical Analyser system in order to increase applications.     

中蜂囊状幼虫病毒VP1基因的优化表达及其免疫原性分析

目的原核表达优化的中蜂囊状幼虫病毒(Chinese sacbrood virus,CSBV)的VP1基因,并分析其免疫原性。方法根据大肠埃希菌密码子偏爱性对野生型CSBV VP1(wt VP1)基因进行优化(opti VP1),将基因wt VP1和opti VP1分别克隆至p GEX-6P-1原核表达系统,构建原核表达质粒p GEX-6P-wt VP1和p GEX-6P-opti VP1,分别转化E.coli BL21,经IPTG诱导表达,并对诱导温度、IPTG终浓度及诱导时间进行优化,诱导蛋白经Western blot鉴定;重组蛋白经GSH-琼脂糖凝胶层析纯化;分别用PBS、纯化的GST标签蛋白、纯化的重组蛋白及CSBV纯化病毒免疫小鼠,经间接ELISA法检验各组小鼠的血清抗体效价。结果优化后的VP1基因序列降低了密码子影响指数,提高了密码子适应指数;质粒p GEX-6P-wt VP1和p GEX-6P-opti VP1经鉴定证明构建正确;最佳诱导表达条件为:IPTG终浓度0.8 mmol/L,30℃,220 r/min诱导8 h;诱导表达蛋白占菌体总蛋白百分比由wt VP1菌株(5.49±0.30)%提高至opti VP1菌株(59.7±0.51)%,纯化后纯度可达0.5 mg/ml;兔抗GST标签抗体及兔抗CSBV血清均与优化后的重组蛋白发生特异性反应;重组蛋白组小鼠二免后可产生较高水平抗体,明显高于PBS组和GST标签蛋白组(P0.05)。结论通过密码子优化实现了CSBV结构基因VP1的高效表达,表达蛋白可诱导小鼠机体产生特异性抗体,具有良好的免疫原性,为探讨CSBV感染的分子发病机制和制备抗CSBV病毒的多克隆抗体奠定了基础。     

Interpolymer radical coupling: A toolbox complementary to controlled radical polymerization

The current review focuses on the relevance and practical benefit of interpolymer radical coupling methods. The latter are developing rapidly and constitute a perfectly complementary macromolecular engineering toolbox to the controlled radical polymerization techniques (CRP). Indeed, all structures formed by CRP are likely to be prone to radical coupling reactions, which multiply the available synthetic possibilities. Basically, the coupling systems can be divided in two main categories. The first one, including the atom transfer radical coupling (ATRC), silane radical atom abstraction (SRAA) and cobalt-mediated radical coupling (CMRC), relies on the recombination of macroradicals produced from a dormant species. The second one, including atom transfer nitroxide radical coupling (ATNRC), single electron transfer nitroxide radical coupling (SETNRC), enhanced spin capturing polymerization (ESCP) and nitrone/nitroso mediated radical coupling (NMRC), makes use of a radical scavenger in order to promote the conjugation of the polymer chains. More than a compilation of macromolecular engineering achievements, the present review additionally aims to emphasize the particularities, synthetic potential and present limitations of each system.     

Synthesis of well-defined star-branched polymers by stepwise iterative methodology using living anionic polymerization

This article reviews the synthesis of regular and asymmetric star-branched polymers with well-defined structures by methodologies using living anionic polymerization, especially focusing on the synthetic approaches accessible for precisely controlled architectures of star-branched polymers concerning molecular weight, molecular weight distribution, arm number, and composition. The reason for selecting living anionic polymerization from many living/controlled polymerization systems so far developed is that this living polymerization system is still the best to meet the strict requirements for the precise structures of star-branched polymers. Furthermore, we herein mainly introduce a novel and quite versatile stepwise iterative methodology recently developed by our group for the successive synthesis of many-armed and multi-compositional asymmetric star-branched polymers. The methodology basically involves only two sets of the reaction conditions for the entire iterative synthetic sequence. The reaction sequence can be, in principle, limitlessly iterated to introduce a definite number of the same or different polymer segments at each stage of the iteration. As a result, a wide variety of many-armed and multi-compositional asymmetric star-branched polymers can be synthesized.     

横河控制系统无缝集成解决方案在海上平台项目中的应用

以SZ36-1CEPK海上平台项目为例介绍了横河DCS与SIS系统的无缝集成解决方案。     

基于C/S模型的过山车虚拟协同设计与仿真系统

为了解决传统设计的弊端,有效降低设计成本,提高过山车的安全性和运动特性,根据国内过山车游乐设备研制的实际情况,开发了基于C/S模型的过山车虚拟协同设计与仿真系统,构建了该系统的6层次模型的体系结构,介绍了面向装配的、具有交互界面的支持多用户协同设计的参数化设计子系统,以及由有限元分析平台、协同仿真平台和安全性评价平台3个功能模块组成的虚拟样机分析子系统.虚拟样机分析子系统能预估和评价设计方案和设计产品的产品功能、机械性能、安全性及可加工性等方面可能存在的问题,能将全部分析数据反馈给设计过程.采用数据库技术构建了含2个子系统的数据管理系统,实现多个子端自动加载、卸载数据源和对数据快速准确的传输、保存.