Synthesis, characterization and antimicrobial activity of zinc and cerium co-doped a-zirconium phosphate

A series of zinc ions or/and cerium ions co-doped α-zirconium phosphate (Zn-Ce@ZrPs) were prepared. The novel Zn-Ce@ZrPs were characterized and the antibacterial activity on Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were tested. The results showed that zinc ions (Zn2+) or/and cerium ions (Ce3+) were combined with ZrP, and the Ce3+ was adsorbed on the surface of ZrP through hydrogen bonds, while Zn2+ intercalated into the interlayer of ZrP. Zn-Ce@ZrPs showed excellent synergistic antibacterial activity. When Zn2+/Ce3+ atomic ratio was 0.6, the Zn-Ce@ZrP3 showed the highest synergistic antibacterial efficiency, suggesting great potential application as antibacterial agents in microbial control.     

Effect of Ce3＋ on membrane permeability ofEscherichia coli cell

This study aimed to delineate the antibacterial mechanism of rare-earth ion Ce 3+ to the target organism Escherichia coli cell, and the most important purpose was to identify its biological effect of increasing the E. coli cell membrane permeability. The antibacterial activities of Ce 3+ to E. coli cells were tested, and then the permeability of outer membrane (OM) and inner membrane (IM) were studied by N-phenyl-1-naphthylamine (NPN) and o-nitrophenyl-β-D-galactopyranoside (ONPG) methods separately. Through these experiments we concluded that the E. coli cells grown to log phage were more sensitive to Ce 3+ than the ones not at this stage; the structure of membrane was destroyed and the permeability of both OM and IM was obviously increased by Ce 3+ ; there should be certain interactions between Ce 3+ and some proteins inside the cell, which impeded the physiological activities of bacteria.     

木塑复合材料真菌耐久性研究进展

综述了木塑复合材料(WPC)的真菌耐久性的研究情况,主要介绍了WPC的真菌危害情况(包括腐朽真菌降解及霉菌侵染等)和影响其真菌耐久性的主要因素,并对提高WPC真菌耐久性的方法进行了探讨,为WPC真菌耐久性的提高及其相关标准的制定奠定基础。     

高分子材料微生物腐蚀的研究概况

简要介绍了高分子物质微生物腐蚀的作用机理:合成高分子材料能否成为异氧微生物的底物主要取决于其化学结构、结合性能、微生物群落。生物腐蚀的程度还取决与聚合物的分子量、结晶度、物理形态。高分子的生物腐蚀影响其在多种工业材料的应用,包括航空航天结构复合材料、高分子增塑剂和添加物、电绝缘聚酰亚胺。     

抗菌的季鏻阳离子改性蒙脱土的制备及表征

采用离子交换法将不同含量的十六烷基三丁基季鳞阳离子交换到蒙脱土的层间得到改性蒙脱土,并对其结构和性能进行了表征.热重分析(TGA)结果表明改性蒙脱土中季鳞阳离子的热分解起始温度都大于220℃,具有良好的热稳定性.通过X-射线衍射法(XRD)分析发现改性蒙脱土的层间距随着季鳞阳离子含量的增加而增加.扫描电镜观察结果发现:钠基蒙脱土为片状结构,粒子之间相互缠绕在一起;而改性蒙脱土的表面则显示出不规则的形状.随着改性蒙脱土中季鳞阳离子含量的增加,其抗菌活性逐渐增强.季鳞阳离子含量为22.61%(质量分数)的QPC-MMT2样品,其对E.coli和S.aureus的最低抑菌浓度(MICs)分别为1000 mg·L-1和30 mg·L-1,显示出良好的抗菌效果.     

冻融循环对木塑复合材料质量和防霉性能的影响

主要研究了冻融循环对木粉/高密度聚乙烯(HDPE)(质量比60/40)、竹粉/HDPE(质量比60/40)复合材料质量变化及防霉性能的影响。结果表明:解冻温度和循环次数对木塑复合材料的质量变化有一定影响,当解冻温度为28℃,冻融循环后木塑材料的质量略有增加,随循环次数的增加而增大;而解冻温度为60℃时,则冻融循环后材料的质量略有下降,随循环次数的增加而下降更多。然而,对冻融循环后木塑材料防霉性能的测试结果表明:冻融循环(包括循环温度及循环次数)对木塑材料的防霉性能并无明显影响。     

Structure and synergetic antibacterial effect of zinc and cerium carried sodium zirconium phosphates

Zinc and cerium carried zirconium phosphates (Zn-Ce/ZrPs) were prepared by exchanging zinc and cerium cations into sodium zirconium phosphate (NaZrP) through the ion-exchange method and characterized by X-ray diffraction(XRD), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). Furthermore, the specific surface area, zeta potential and antibacterial activity were tested. The results showed that Zn-Ce/ZrPs were with hexagonal crystal system, and the surface area of Zn-Ce/ZrPs increased much more than that of NaZrP. Zn-Ce/ZrPs showed obvious synergetic antibacterial effect, and have the potential to be used as antibacterial agents in environmental control.     

发酵法生产均聚氨基酸研究进展

简单介绍聚氨基酸的化学性质和基本特性，并分别描述两种常见均聚氨基酸如聚赖氨酸、聚谷氨酸的发酵生产和提取方法。聚赖氨酸一般采用白色链霉菌Streptomyces albulus作为发酵生产菌株，在合适的发酵条件下，产率最高达48．3g／L；而聚谷氨酸一般采用芽孢杆菌属的某些种如地衣芽孢杆菌Bacillus lichenifonnis作为发酵生产菌株，不同菌种、培养基和发酵工艺条件，γ-聚谷氨酸的产率是不同的，一般产率在5～50g／L。     

异噻唑啉酮衍生物类工业杀菌剂的研究进展

异噻唑啉酮类衍生物因其广谱的抗菌性而被广泛用于工业生产的诸多领域。本文主要阐述了该类工业杀菌剂的发展历程、主要化合物结构种类、特性、在工业上的应用及微生物对其产生抗药性等方面的研究进展,并对其今后的发展动向做了展望。     

木塑复合材料的生物因子危害研究进展

综述了生物因子对木塑复合材料(WPC)的侵蚀情况,主要介绍了霉菌、腐朽真菌、白蚁、藻类、细菌及海生生物等对WPC的危害情况,并对提高WPC生物因子抗性的方法进行了初略探讨。