羧甲基壳聚糖季铵盐的制备及其抑菌性能研究

以不同分子量的壳聚糖为原料合成了一种新型水溶性O-羧甲基-N-三甲基壳聚糖季铵盐(CMTMC),用FTIR表征了其结构,同时进行了抑菌实验.结果表明在水介质中CMTMC对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌的最低抑菌浓度分别为1 μg·mL-1、1 μg·mL-1和2 μg·mL-1,在0.5%醋酸溶液介质中的抑菌效果比在水介质中更好.     

海南桉叶提取物熊果醇和桉叶油的抑菌特性研究

从海南桉叶中提取有效组分熊果醇和桉叶油,并研究了其抑菌活性.结果表明,熊果醇对枯草芽孢杆菌、金黄色葡萄球菌、白色念珠菌、大肠杆菌和短小芽孢杆菌等有明显的抑制作用,对藤黄微球菌没有抑制作用,对大肠杆菌的最低抑菌浓度(MIC)为587 μg·mL-1;桉叶油只对大肠杆菌、白色念珠菌有较明显的抑制作用.     

田基黄总黄酮提取物的抑菌性能研究

用抑菌圈法考察了田基黄总黄酮浓度、pH和处理温度对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌的抑菌活性.结果表明,总黄酮提取物对大肠杆菌、枯草芽孢杆菌和金黄色葡萄球菌都具有良好的抑菌活性,最小抑菌浓度分别为3.125,6.25,1.562 5 μg/mL.总黄酮浓度为12.5 μg/mL的田基黄提取物对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌分别在pH为8,7～8和5抑菌活性最大.总黄酮提取液具有较强的耐热性能,在20℃和80℃加热处理30 min后对大肠杆菌、枯草芽孢杆菌和金黄色葡萄球菌的抑菌圈分别为12.8,10.2,11.3 mm和12.0,10.0,10.8 mm.     

羧甲基槲皮素的体外抑菌活性研究

考察了槲皮素的水溶性衍生物3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠的体外抑菌活性。方法:用培养基将3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠进行倍比稀释,加入菌液至终浓度为107 cfu.mL-1,通过比浊法测定加药后细菌的生长情况。结果是3′-羧甲基槲皮素钠对金黄色葡萄球菌Staphylococcus aureus、金黄色葡萄球菌Wright、肺炎克雷伯菌、大肠杆菌、中间普氏菌的最小抑菌浓度分别为0.05,0.1,0.8 mg.mL-1,1.6,0.05 mg.mL-1;最小抑菌浓度下的抑菌率分别为98.8%,87.3%,83.9%,100.0%,100.0%。4′-羧甲基槲皮素钠对金黄色葡萄球菌、带荚膜的金黄色葡萄球菌、肺炎克雷伯菌、大肠杆菌、中间普氏菌的最小抑菌浓度分别为0.05,0.1,0.8,1.6,0.05 mg.mL-1;最小抑菌浓度下的抑菌率分别为92.4%,78.6%,87.5%,97.9%,99.8%。结论:3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠对革兰阳性菌、革兰阴性菌及厌氧菌均有良好的抑菌作用。     

柚子叶等5种中药对鸡粪中大肠杆菌的体外抑菌试验

目的:探讨柚子叶、狗肝菜、青蒿等中药对鸡源性大肠杆菌(Escherichia coli,E.coli)的体外抗菌效果。方法:运用糖发酵实验、甲基红实验、吲哚实验、溶血实验以及麦康凯培养基实验鉴定可疑菌;牛津杯法测定上述中药的抑菌直径;二倍稀释法测定上述中药的最低抑菌浓度和最低杀菌浓度。结果:上述五种中药对鸡大肠杆菌均有抑制作用,实验中抗菌效果最优的为柚子叶,其次为防风、牛蒡,青蒿、狗肝菜抑菌效果最差,最低抑菌浓度分别为62.5、125、125、250、250 mg/m L;最低杀菌浓度分别为125、250、250、500、500 mg/m L。结论:柚子叶对鸡源性大肠杆菌有一定抗菌作用。     

8种调味料提取液抑菌效果研究

研究8种调味料(丁香、八角、花椒、肉桂、藿香、肉豆蔻、高良姜、生姜)超声提取液对常见致病菌与腐败菌的抑菌效果,为研制天然食品防腐剂提供依据。采用牛津杯法测定抑菌圈直径,采用液体稀释法测定最低抑菌浓度(MIC)。丁香提取液对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌和黑曲霉的抑制作用最大,其MIC为15.625 mg/m L,其次是肉桂,其它调味料对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌有较好的抑菌效果,而对黑曲霉抑菌效果较差。8种调味料提取液的抑菌效果受到p H值影响较大,但几乎不受温度和紫外光照的影响。丁香和肉桂对4种菌均显示了良好的抑菌活性,八角、花椒、高良姜和生姜次之,肉豆蔻和藿香的抑菌效果最差。     

邻、间、对双胍基苯甲酸盐酸盐抗菌活性的研究

以邻、间、对氨基苯甲酸为起始原料,在盐酸存在下分别与双氰胺合成了中间体邻、间、对双胍基苯甲酸盐酸盐,分别研究了邻、间、对双胍基苯甲酸盐酸盐对革兰氏菌的抗菌活性。实验表明,邻、间、对双胍基苯甲酸盐酸盐对大肠杆菌、金黄色葡萄球菌都具有抑制作用,抗菌活性随浓度的增加而增强;邻双胍基苯甲酸盐酸盐对大肠杆菌、金黄色葡萄球菌最低抑菌浓度分别为0.064mg.mL-1和0.032mg.mL-1,优于间、对双胍基苯甲酸盐酸盐。     

家蝇抗菌肽抑菌活性及其稳定性研究

通过体外抑菌实验,采用纸片扩散法对家蝇抗菌肽的抑菌性进行定性研究。试验用菌有金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白色念珠菌和黑曲霉菌。在对家蝇抗菌肽抗菌谱研究的基础上,进一步用肉汤稀释法（试管法）定量测定其最低抑菌浓度（MIC）,并对其稳定性进行研究。结果表明,家蝇抗菌肽对金黄色葡萄球菌、绿脓杆菌和大肠杆菌3种细菌有较好的抑制作用,而对白色念珠菌和黑曲霉没有明显的抑制作用,对金黄色葡萄球菌、绿脓杆菌和大肠杆菌最低抑菌浓度（MIC）分别为0.156 mg/mL、0.312 5 mg/mL和6.25 mg/mL。另外,对其稳定性进行讨论,结果表明,家蝇抗菌肽的稳定性良好。     

凤眼草抑菌活性成分的研究

对苦木科臭椿属植物臭椿的果实凤眼草(Ailanthus altissima)的95％乙醇提取液的抑菌活性进行了研究.利用系统溶剂萃取法得到了石油醚提取物、氯仿提取物、乙酸乙酯提取物和正丁醇提取物,重点研究了4种提取物对枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌的抑菌性和最低抑菌浓度.结果表明,乙酸乙酯提取物和正丁醇提取物均...     

鸡蛋花挥发油的提取及其抗氧化和抑菌活性研究

以鸡蛋花为原料,采用索氏提取法制备得到鸡蛋花醇提物,采用DPPH·自由基清除法及测定抑菌圈直径法研究了鸡蛋花醇提物的抗氧化及抑菌活性。结果表明,鸡蛋花醇提物对DPPH·具有较好的清除效果,清除率达93%,其DPPH·清除率与样液浓度呈量效关系,IC50为2.88 mg/mL;鸡蛋花醇提物具有一定的抑菌活性,抑菌效果金黄色葡萄球菌枯草芽孢杆菌大肠杆菌沙门氏菌,其最低抑菌浓度分别为金黄色葡萄球菌3.2 mg/mL,枯草芽孢杆菌和大肠杆菌6.3 mg/mL,沙门氏菌12.5 mg/mL。     

Synthesis and some studies on fluorinated cationic surfactants: surface and biocidal activities

Three fluorinated cationic surfactants were prepared by condensing N-(2-bromoethyl)perfluoroalkylamides with stoichiometric amounts of pyridine, triethanolamine, and triethylamine to produce three quaternary ammonium salts. The surface and biocidal properties of these surfactants were investigated to find the relation between the structure of the hydrophilic portion of the compounds and their efficiency as biocides. The properties studied included critical micelle concentration (CMC), effectiveness (II_CMC), surface excess concentration (T_max), and area occupied by a molecule (A_min). Free energies of micellization (ΔG _mic ^o) and adsorption (ΔG _ads ^o) of the surfactants in aqueous solution were calculated. The minimal inhibitory concentrations of the prepared compounds were tested against five strains as representative group of microorganisms.     

新型吲哚类防污剂抑菌性能评价

对6种含TBG衍生结构的N-取代吲哚衍生物进行了抑菌活性检测。结果表明,各吲哚衍生物对大肠杆菌和金黄色葡萄球菌两种供试菌株均有一定的生长抑制作用,对金黄色葡萄球菌的作用明显优于对大肠杆菌的作用。其中ClG-BP抑菌效果最好,对大肠杆菌和金黄色葡萄球菌最小抑菌质量浓度分别为0.12 mg/mL、0.01 mg/mL。各化合物抑菌性能相对大小为:ClG-BP>ClG>BrG-BP>ClG-MP>BrG>BrG-MP。     

无机抗菌粉体中银价态与抗菌性能研究

以SiO2为基体，Ag^ 作为主要抗菌成分的无机抗菌剂粉体，控制银离子的含量为n（Ag）：n（Si）=0.0286时，在无机抗菌剂中分别引入摩尔分数约30％的Al^3 或60％的Zn^2 ，用于稳定无机抗菌剂中银价态，制备出不变色的无机抗菌粉末。利用XPS技术分析和抗菌性能测试，研究不同温度下抗菌粉体的抗菌性能和银价态关系，揭示含银无机抗菌剂银价态和抗菌性能关系及其机制。研究发现：银离子的价态对粉体的抗菌性能影响很大，当银离子以AgO状态存在时，粉体的抗菌性能较好，若为银单质存在，则抗菌性能下降。Zn^2 的加入，有利于稳定高温时抗菌粉体中的银离子仍以银的氧化物状态存在。     

天然去屑剂CMS的性能及应用研究

去屑剂CMS以苦参、黄芩、积雪草、黄连、仙鹤草和蒲公英等天然中草药提取物为原料,以对马拉色菌的杀菌活性为依据,考察其对头屑的抑制作用,并与去屑剂ZFT、OCT做对照.结果显示,去屑剂CMS对马拉色菌的最低抑菌浓度(MIC)为10ug/mL,且无毒、无刺激.在洗发水中添加千分之五的CMS.去屑效果明显.     

具有给定陈不变量的一般型极小代数曲面的构作

证明了１个定理：若预先给定的正整数对（ｘ，ｙ）满足：ｘ≥３８４０８８，ｙ是偶数，且７３７８８ｘ≤ｙ≤９２５８０１０４２９ｘ－１９２８７７，则可以构造１个一般型的极小代数曲面Ⅹ，使Ⅹ具有预先给定的陈不变量Ｃ２１（Ｘ）＝ｙ，χ（Ｘ）＝ｘ，且Χ具有纤维化。     

Coarse‐grained models for frontal photopolymerization with evolving conversion profile

We introduce a series of ‘minimal’ models to describe a common light‐driven directional solidification process, known as frontal photopolymerization (FPP ), focusing on experimental observables: the solidification kinetics, light attenuation and spatiotemporal monomer‐to‐polymer conversion. Specifically, we focus on FPP propagation that yields conversion profiles that are not invariant with time, and which cannot be simply described by the presence of mass or heat diffusion. The models are assessed against experimental data for the photopolymerization of a model trimethacrylate system. We find that the simplest model, comprising a single equation of motion for the conversion fraction ? and a generalized Beer–Lambert law, can only describe the experimental data by assuming an unphysical variation in optical absorption. Introducing a ? ‐dependent reaction constant K _eff is found to require a time dependence, regardless of the functional form in ? . We conclude by introducing a ‘minimal’ chemical model, which is based on a simple three‐step reaction scheme involving the spatiotemporal evolution of the photoinitiator fraction, relative fraction of radicals and monomer conversion fraction, that is able to capture the experimental data with a small number of parameters and under reasonable FPP assumptions. Our framework provides important predictive ability for ubiquitous solidification and patterning processes, including three‐dimensional printing, via photopolymerization. © 2017 Society of Chemical Industry     

Cu2+对泥鳅急性毒性试验

基于目前水环境重金属污染事件的频繁发生,人们对水生态系统的关注也越来越高.一些重金属在水体中可转化为持久的高毒性的金属化合物,通过在机体内富集并通过食物链放大从而威胁到人们的身体健康.[1]本文选用铜离子对泥鳅进行了急性毒性试验,用以对环境监测和鱼类养殖提供理论上的参考.     

某钛铁矿矿石可选性试验研究

为了提高某低品位难选钛铁矿的综合利用水平,在矿石性质分析的基础上,进行了系列试验,结果表明:原矿经脱泥筛分预处理后,进入重选作业,重力选矿采用螺旋溜槽粗选,所得粗精矿经磨矿后进行摇床精选,获得重选精矿;重选精矿再通过磁选产出最终精矿,磁选采用先弱磁选后强磁选,弱磁选产出钒钛磁铁矿精矿,强磁选产出钛铁矿精矿.当给矿TiO2品位3.31％时,通过重-磁选矿工艺,可获得TiO2品位18.25％、回收率2.81％的钒钛磁铁矿精矿,TiO2品位49.39％、回收率47.44％的钛铁矿精矿,累计精矿TiO2品位45.08％,TiO2总回收率50.25％.     

具有指定陈数的一般型极小纤维化代数曲面

证明了对于指定的正整数对（ｘ，ｙ），当ｘ大于某一大整数，（ｘ，ｙ）处于由一些直线围成的区域内（直线的斜率最高可达到８８７７１），总可以构造一个一般型极小纤维化代数曲面Ｘ，使Ｘ具有指定的陈数Ｃ２１（Ｘ）＝ｙ，χ（Ｘ）＝ｘ。     

In vitro fracture resistance of endodontically treated premolar teeth restored with a direct layered fiber-reinforced composite post and core

Methods for restoring endodontically treated teeth fall short of restoring the physiologic mechanical properties. Fracture of endodontically treated teeth is a common type of clinical failure. New treatment modalities or perfected versions of existing treatment concepts need to be tested to find a biomimetic solution. A novel method of restoring endodontically treated teeth is presented and compared in vitro with currently accepted restorative methods. Seventy-two extracted and endodontically treated maxillary premolar teeth were divided into six groups (n = 12) depending on restorative technique (Groups 1–6). Group 1: fiber-reinforced composite post (FRC), Group 2: direct layered short FRC post and core, Group 3: short fiber-reinforced obliquely layered composite restoration, Group 4: microhybrid composite restoration, Group 5: fiber-reinforced box, Group 6: control. Specimens were submitted to static fracture resistance test. Fracture thresholds and fracture patterns were evaluated. Group 6 exhibited the highest fracture resistance. Group 2 yielded the highest fracture resistance among the restored groups. The fracture resistance of Group 2 did not differ significantly from Group 6. Groups 1, 3, 4, 5 proved to be significantly different from the control group. There was no statistically significant difference among restored groups. Fracture patterns of tested groups were dominantly non repairable opposed to control groups mostly repairable fractures. Application of direct-layered short FRC post and core in endodontically treated premolars performed statistically similarly in the studied conditions as natural teeth. Therefore, it seems a promising alternative to current endo-restorative solutions. However, further testing is required.