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A stain-based screening method was developed to screen different catalyst coatings for their germicidal activity. A Baclight dead/live bacteria viability kit (invitrogen, molecular probes) was used for staining the cell. The screening was carried out following a standard procedure. This included loading cell suspension to solid surface and maintaining contact for 30 min, then staining with a mixture containing dyes. The stained cells were observed using an epifluorescent microscope and photographed with a CCD camera under UV. Metal-doped TiO2 coatings on AI plates were prepared and tested for non-UV germicidal activity without using UV. It was tested using model microorganisms such as Bakers Yeast (Saccharomyces cerevisiae), Bacillus subtilis, Pseudomonas putida, and Escherichia coli. On the basis of the germicidal activity of catalyst and the degree of damage caused to the cells, the stained cells may appear green (viable), green with red or yellow nuclei and yellow (compromised) or red (nonviable). According to their stained color, cells were counted to calculate the percentage of dead, live, and compromised cells. Compromised cells are cells that grow very slowly after reculturing indicating a degree of reversible cell damage. Screening the germicidal activity using this staining method is accurate and efficient, and requires less time than the culture-based method. A modification to the procedure for measuring germicidal activity of rough surfaces or fibrous coatings was developed. Both TiO2 and metal-doped TiO2 (Ag, Pt, Au, Cu) possess non-UV based germicidal activity. The germicidal activity of TiO2 was found to be related with its wetting property and can be improved by UV irradiation before testing. It is not greatly affected by contact time, indicating a fast acting germicidal activity. 相似文献
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Endocrine disrupting chemical(EDC) pollution in river-based artificial groundwater recharge using reclaimed municipal wastewater poses a potential threat to groundwater-based drinking water supplies in Beijing, China. Lab-scale leaching column experiments simulating recharge were conducted to study the adsorption, biodegradation, and transport characteristics of three selected EDCs: 17β-estradiol(E2), 17α-ethinylestradiol(EE2) and bisphenol A(BPA). The three recharge columns were operated under the conditions of continual sterilization recharge(CSR), continual recharge(CR), and wetting and drying alternative recharge(WDAR). The results showed that the attenuation effect of the EDCs was in the order of WDAR CR CSR system and E2 EE2 BPA, which followed first-order kinetics. The EDC attenuation rate constants were 0.0783, 0.0505, and 0.0479 m-1 for E2, EE2 and BPA in the CR system, respectively. The removal rates of E2, EE2, and BPA in the CR system were 98%, 96% and 92%, which mainly depended on biodegradation and were affected by water temperature.In the CR system, the concentrations of BPA, EE2, and E2 in soil were 4, 6 and 10 times higher than in the WDAR system, respectively. According to the DGGE fingerprints, the bacterial community in the bottom layer was more diverse than in the upper layer, which was related to the EDC concentrations in the water-soil system. The dominant group was found to be proteobacteria, including Betaproteobacteria and Alphaproteobacteria, suggesting that these microbes might play an important role in EDC degradation. 相似文献
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伦海波 《中国环境管理干部学院学报》2014,(1):82-84
实验室资源优化配置和科学管理是高职院校提高教学、科研水平和人才培养质量的重要途径。当前高职院校实验室资源配置与管理中普遍存在实验室分散封闭管理、资源配置缺乏计划、实验室没有充分利用以及设备缺乏维护保养四个方面问题,针对这些问题应从管理体制改革、设备申报采购制度、实验室潜力开发以及开展培训、提高管理人员水平四个方面来实现实验室合理配置资源、科学规范管理。 相似文献
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全国23个城市水源水中邻苯二甲酸酯代谢物浓度调查 总被引:1,自引:0,他引:1
采用UPLC-MS/MS方法对中国23个城市的90个自来水厂141个水源水样中5种常用PAEs的8种代谢产物进行检测.结果发现,所有自来水水源水中均检出了MPAEs,邻苯二甲酸单正丁酯(MnBP)检出浓度最高,为74.7ng/L.水源水中邻苯二甲酸单乙酯(MEP),邻苯二甲酸单异丁酯(MiBP)和MnBP浓度与邻苯二甲酸二乙酯(DEP),邻苯二甲酸二异丁酯(DiBP)和邻苯二甲酸二正丁酯(DnBP)浓度分别呈显著相关,表明两者可能是同源.邻苯二甲酸二(2-乙基己基)酯(DEHP)二级代谢产物所占DEHP一级、二级代谢产物浓度和(∑DEHP)为4.0%±5.6%,和天然水体中DEHP的微生物降解结果类似,水源水中的MPAEs可能来自PAEs在自然水体中的微生物降解. 相似文献
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Chun Chen Yuzheng Wang Yuanyuan Zhang Xiaoxiu Lun Chengtang Liu Yujing Mu Chenglong Zhang Pengfei Liu Chaoyang Xue Min Song Can Ye Junfeng Liu 《环境科学学报(英文版)》2019,31(6):316-326
The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate(NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented:1/8 times the concentration of Gamborg B5 vitamin mixture with p H = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200–2000 μmol/(m2·sec) and temperature range of 13.4–28.7°C. The nitrogen dioxide(NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers.Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere(from-1.01 to-2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere(from-1.12 to-3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time. 相似文献
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结合长江江苏镇江段某码头堆场地基采用真空联合堆载预压法加固处理工程,通过现场钻孔埋设孔隙水压力计,对长江漫滩相软土地基加固过程中孔隙水压力的发展变化过程进行了测试分析。结果表明:真空预压区,加固30d后地基中孔隙水压力变化基本稳定,且土中超静孔隙水压力的消散受该深度排水板中真空荷载的影响十分显著;排水板中真空荷载随深度衰减,衰减速率与排水板周围土层性质密切相关;通过现场测试得到排水板周围为长江漫滩相淤泥质粉质黏土时,真空荷载沿排水板深度衰减速率约为3kPa/m。 相似文献
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开花前后变水条件对春小麦的补偿效应 总被引:1,自引:0,他引:1
在防雨棚内的盆栽实验条件下,研究了4种梯度的10种不分组合对红芒麦和宁春10号产量及耗水量等的影响。结果表明,试验期间充分灌水,轻度,中度,重度干旱处理,随着干旱程度的加剧,株高,干物质积累,产量,耗水量都逐渐减少;红芒麦灌浆期不同程度的,匀有利于产量的形成,促进物质运输,提高千粒重,同时减少水分消耗,提高WUE;孕穗期干旱处理后,灌浆期复水,会造成减产,和灌浆期相比,孕穗期是水分的敏感的时期,而灌浆期对水分亏缺不敏感,两种小麦相比较,宁春10号耗水量大,产量低,抗旱性较强,图2表2参7 相似文献