聚六亚甲基胍杀菌剂的制备及其在海洋油田中的应用

以己二胺和盐酸胍为原料,合成一种聚六亚甲基胍杀菌剂(BHS-49)。与其他主流杀菌剂进行对比,侧重研究其杀菌能力,BHS-49加注质量浓度30mg/L时,SRB含量最低,平均值为25.5个/mL。在海上油田开展现场试验,结果显示,各级检测点细菌含量明显降低,FPSO缓冲罐出口细菌含量降低至6个/mL。同现场在用杀菌剂BHS-29相比,SRB含量降低76%,满足排放要求。与此同时,杀菌剂BHS-49加注期间,现场流程稳定,各监测点出口水质未出现波动。     

盐酸胍中微量砷的光度测定

通过试验认为盐酸胍的存在对红色银胶体吸收曲线、锌用量、反应时间和有色物的稳定性等均无影响 ,并建立了二乙基二硫代氨基甲酸银法测定盐酸胍中微量砷含量的方法。测定 4次生物级盐酸胍中砷的质量分数平均值为 0 12× 10 - 6 ,相对标准偏差为 15 %。当样品中砷的质量分数为 0 5× 10 - 6 和 1 0× 10 - 6 时 ,测定 4次所得标准偏差分别为 8%和 5 %。     

盐酸胍在阻挡层化学机械抛光中对速率选择性及表面形貌的影响

We propose an alkaline barrier slurry containing guanidine hydrochloride（GH） and hydrogen peroxide.The slurry does not contain any corrosion inhibitors, such as benzotriazole（BTA）. 3-inch samples of tantalum copper and oxide were polished to observe the removal rate. The effect of GH on removal rate selectivity along withhydrogenperoxidewasinvestigatedbycomparingslurrycontainingGHandH2O2withslurrycontainingonly GH. Details about the tantalum polishing mechanism in an alkaline guanidine-based slurry and the electrochemical reactions are discussed. The results show that guanidine hydrochloride can increase the tantalum polishing rate and the selectivity of copper and barrier materials. The variation of the dishing and wire line resistance with the polishing time was measured. The dishing value after a 300 mm pattern wafer polishing suggests that the slurry has an effective performance in topography modification. The result obtained from the copper wire line resistance test reveals that the wire line in the trench has a low copper loss.     

Analysis of P. aeruginosa disinfectant sensitivity and microbial adhesions to worn cosmetic contact lenses

PurposeTo compare the sensitivity of two genotypes of P. aeruginosa to various disinfectant solutions and analyze the attached bacteria on worn cosmetic contact lenses (cosCLs).MethodsIn this prospective study, healthy volunteers wore etafilcon (brown), nelfilcon (gray), or hilafilcon (black) cosCLs and microbial adhesion analysis was performed. A rub-off test determined pigment dislodgement. Disinfectant sensitivity to Optifree Replenish (Alcon), Optifree Pure Moist (Alcon), Renu Fresh (Bausch & Lomb), and AoSept Plus (Ciba Vision) was tested at various disinfection times and compared between various genotypes and Type III secretion (T3S) system mutants.ResultsOf the 1152 cosCLs collected, 364 were culture positive (32%). The highest rate of culture-positive lens was hilafilcon (chi square, P = 0.0001). Hilafilcon also had a significantly greater number of isolates than etafilcon (P < 0.0001). Hilafilcon was the only lens to fail the rub-off test. Cytotoxic strains were significant more resistant to Renu Fresh than were invasive strains, even at 100% of recommended disinfection time (P = 0.0005). Of the tested disinfectants, Renu Fresh was significantly less effective in killing both genotypes of P. aeruginosa compared to AoSept Plus at all time points (25%, 50%, 75%, and 100% recommended disinfection time, P = 0.0001, 0.0001, 0.0005, and 0.0005, respectively). When the T3S system was dysfunctional, mutant strains were all susceptible to disinfectants (P = 0.0001 for both invasive and cytotoxic strains).ConclusionPseudomonas species is commonly found on cosCLs of asymptomatic individuals. Wearers of cosCLs that dislodge pigments may be predisposed to microbial contamination. Cytotoxic strains are more resistant to disinfectant solutions, especially to Renu Fresh. P. aeruginosa disinfectant resistance requires a functional T3S system.     

Internalization of Salmonella enterica by tomato fruit

Since 1990, several outbreaks of foodborne illness have been associated with the consumption of raw tomatoes. Various serovars of the bacterial pathogen, Salmonella enterica, were responsible for these illnesses. Fruits and vegetables are not a normal niche for mammalian pathogens. Hypotheses concerning introduction of Salmonella into tomatoes range from contamination in the field or greenhouse to direct or cross-contamination during harvest, handling and preparation of tomato as a raw agricultural commodity. Many different reports have shown that Salmonella can not only survive in tomato fruit but also proliferate from small, relatively inconsequential populations to numbers known to incite illness even in healthy individuals.Herein, production, harvest and handling of fresh market tomatoes are evaluated in terms of how Salmonella might contaminate this crop. Physical principles are emphasized, whereas biological factors are included where appropriate. Salmonella is viewed as a bacterium that is affected by the same physical principles affecting bacteria naturally occurring in the environment surrounding tomato fruit as well as tomato plants during production, harvest and handling.     

Synthesis,characterization, toxicological and antibacterial activity evaluation of Cu@ZnO nanocomposites

Cu@ZnO is an important class of material with applications as catalysts, photocatalysts, optoelectronic devices and antimicrobial agents. Because of its potential for large-scale applications and its high redox activity, detailed examination of the properties and risk assessment of this class of materials should be performed. In this work, Cu@ZnO composites were synthesized using a two-step procedure. ZnO crystalline nanostructured materials were prepared within minutes by a solvothermal microwave-assisted method. Deposition of copper nanoparticles on the surface of ZnO was conducted by reduction of Cu²⁺ in ethylene glycol (EG). Copper nanoparticles with different morphologies (needle-like and spheres) were deposited on the surface of ZnO. The antibacterial activity of Cu@ZnO composites was evaluated using E. coli and S. aureus as model organisms. The Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were evaluated for Cu@ZnO composites under visible light radiation (VLR) and in the dark (D). The composites exhibit antibacterial activity under VLR at low concentrations: 250 μg/mL and 750 μg/mL for E. coli, and 250 μg/mL and 500 μg/mL for S. aureus. Copper nanoparticles exert antibacterial activity and can be used to inhibit the growth of microorganisms in the absence of irradiation of Cu@ZnO material. Better antibacterial activity of Cu@ZnO material was achieved under radiation, demonstrating the synergic activity of Cu and ZnO materials for disinfection. Toxicity of the material was assessed towards Daphnia magna (D. magna) and Lecane papuana (L. papuana). Composites exert toxicity at lower concentrations than ZnO, observing LC50 values for L. papuana of 79.30 ± 6.70 μg/mL, and 5.59 ± 0.46 μg/mL for ZnO and Cu@ZnO, respectively. For D. magna, a LC50 of 9.66 ± 1.22 μg/mL (Cu@ZnO) was observed. Although Cu@ZnO can be considered as potential candidate for the development of efficient antibacterial agents, its antibacterial activity is achieved at doses that can be harmful to aquatic invertebrates. Thus, its application should avoid its entry to aquatic environments.     

Nitrogen-doped titanium dioxide photocatalysts for visible response prepared by using organic compounds

In order to utilize visible light in photocatalytic reactions, nitrogen atoms were doped in commercially available photocatalytic TiO₂ powders by using an organic compound such as urea and guanidine. Analysis by X-ray photoelectron spectroscopy (XPS) indicated that N atoms were incorporated into two different sites of the bulk phase of TiO₂. A significant shift of the absorption edge to a lower energy and a higher absorption in the visible light region were observed. These N-doped TiO₂ powders exhibited photocatalytic activity for the decomposition of 2-propanol in aqueous solution under visible light irradiation. The photocatalytic activity increased with the decrease of doped N atoms in O site, while decreased with decrease of the other sites. Degradation of photocatalytic activity based on the release of nitrogen atoms was observed for the reaction in the aqueous suspension system.     

Modified guanidine polymers: Synthesis and antimicrobial mechanism revealed by AFM

Condensation polymerization was used in the preparation of modified guanidine polymers. The polymers were composed of hexamethylene diamine and guanidine hydrochloride with subsequent crosslinking of epichlorohydrin. The two-step synthesis method increased the molecular weight of guanidine polymers, and also enhanced the charge density of the polymer due to the formation of the four-membered rings containing quaternary ammonium groups. This was found to improve antimicrobial activity. The molecular structure of the prepared guanidine polymer was characterized by 2D heteronuclear correlation NMR spectroscopy (C–H COSY). Results indicated that guanidine polymer was a mixture with various structures. UV₂₆₀ absorption and AFM were applied to reveal the dynamic antimicrobial process of guanidine polymer and morphological change of bacterial cells. Both UV₂₆₀ absorption and AFM images showed that the antimicrobial mechanism of guanidine polymer was to destruct the cell membrane of bacteria and cause the leakage of intracellular components from bacterial cells.     

盐酸胍法测定磷酸盐中氧-18的含量

在生物化学中研究生物和植物组织中正磷酸化合物交换时,常用~(18)O作示踪原子来研究生物过程的机理。磷酸盐中~(18)O含量分析方法很多。这些方法由于重复性不好或时间长等而不够理想。Boyer提出的盐酸胍法因快速和准确受到重视。此法是将KH_2PO_4或     

The Biochemical Processes Underlying Ozone Therapy

The type of application, the application range, and the dosage of a medical ozone/oxygen mixture (prepared from the purest oxygen and used in a concentration between 1 and 100 g/mL) have been derived principally from its employment in the preparation of drinking water and the regeneration of liquid waste. This is in the light of its bactericidal and fungicidal properties – which in the clinical field also comes under the heading of disinfection – in addition to the virucidal and thus the overall sterilizing property of ozone. Furthermore, within the biological system, different properties become manifest which may be summarized as its positive effect on blood circulation, and as expressed by an activation of oxygen transportation mechanisms and an improvement of active biological oxygen utilization.