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Contaminated Surfaces (contaminated + surface)
Selected AbstractsAn Evaluation of Physicochemical Treatment Technologies for Water Contaminated with MTBEGROUND WATER MONITORING & REMEDIATION, Issue 4 2000Arturo A. Keller Treatment of methyl tertiary-butyl ether (MTBE) from contaminated surface and ground water supplies presents specific challenges due to the physicochemical properties of MTBE that depend strongly on its hydrophilic nature, and translate into a high solubility in water, and low Henry's constant and low affinity for common adsorbents. We evaluate four treatment technologies-air stripping, granular activated carbon (GAC), hydrophobic hollow fiber membranes, and advanced oxidation processes (AOP)-using ozone or ozone/hydrogen peroxide. Experimental work was carried out to generate parameter values necessary for the design of these processes. Ten different flow rates/concentration combinations were evaluated in our designs to cover the range from high flow rate/low concentration typical of surface water and ground water drinking water supplies to low flow rate/high concentration typical of ground water remediation sites. For all cases, the processes were designed to produce effluent water of 5 ,g/L or less. Capital costs and operation and maintenance costs were determined at the feasibility level by using standard engineering estimating practices. Air stripping is the lowest cost technology for high flow rales (100 to 1000 gpm) if no air treatment is required. Hollow fiber membranes are the lowest cost technology for flow rates of 10 to 100 gpm if no air treatment is required, which is typical at these low flow rates. GAC will be most costeffective at all flow rates if air treatment is required and the influent water has low levels of other organic compounds. AOP using ozone or ozone/hydrogen peroxide is in all cases more expensive than the alternative technologies, and there are sufficient uncertainties at this point with respect to byproducts of AOP to warrant further study of this technology. The cost of treating MTBE-contaminated water for conventional technologies such as air stripping and GAC is 40% to 80% higher than treating water contaminated only with other hydrocarbons such as benzene. [source] Design of an Injectable ,-Hairpin Peptide Hydrogel That Kills Methicillin-Resistant Staphylococcus aureusADVANCED MATERIALS, Issue 41 2009Daphne A. Salick A peptide-based, injectable hydrogel is designed that is inherently antibacterial and can kill methicillin- resistant Staphylococcus aureus (MRSA) on contact. Peptide gels can be used as coatings to inhibit MRSA infection or syringe-delivered to a contaminated surface where the gel kills MRSA on contact. [source] Tracing Salmonella in Alheira processing plantsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007A. Esteves Abstract Aims:, To investigate the sources of Salmonella spp. in Alheira and how to trace it, by studying the way that Salmonella spp. is distributed across production lines, by applying multifactorial correspondence analysis to occurrence data, and through the use of polymerase chain reaction (PCR) molecular typing methods. Methods and Results:, Four production lines, four batches of Alheira and 14 sampling sites were analysed over four sampling periods. Eighty-five Salmonella spp. isolates were obtained from the 896 microbial analyses performed. The basic occurrence analysis values, multiple correspondence analysis and PCR molecular typing methods confirmed that the presence of Salmonella spp. in Alheira was directly related to it being present in casings. Results obtained from PCR molecular typing added a measure of detail, highlighting potential cross-path contamination caused by contaminated surfaces. Conclusions:, The presence of Salmonella spp. in Alheira was a result of the use of contaminated casings, as well as cross-path contamination caused by contaminated surfaces. An analysis of the occurrence data indicated that these casings were the source of Salmonella spp. contamination in Alheira. PCR molecular typing methodology, which is known to have a greater discriminatory power and tracing capacity, indicated the presence of cross-path contamination. Significance and Impact of this Study:, Increased awareness of Salmonella spp. contamination sources and their spread across the production line helps shape the development of new strategies for controlling this pathogen. [source] Antibacterial Activity of an Atmospheric Pressure Plasma Jet Against Relevant Wound Pathogens in vitro on a Simulated Wound EnvironmentPLASMA PROCESSES AND POLYMERS, Issue 3-4 2010Georg Daeschlein Abstract The aim of the study was to test the efficacy of a hand-held atmospheric pressure plasma jet (APPJ) toward typical wound pathogens in vitro simulating antisepsis on wound surfaces. The plasma jet has been proved to be highly effective in vitro against the most commonly encountered pathogenic species of acute and chronic wounds reaching nearly the power of antiseptics. The following bacteria and fungi were treated on half rigid media (agar) imitating wound colonization: methicillin-sensitive Staphylococcus aureus ATCC 1924 (MSSA), Enterococcus faecium ATCC 6057 (EF), Pseudomonas aeruginosa ATCC 15442 (PA), Candida albicans ATCC 10231 (CA), and , -hemolyzing Streptococci of the Lancefield serogroup A (HSA). Highest reduction factor (RF) was obtained treating PA (RF 4.0) followed by HSA (3.2), MSSA (2.7), CA (2.0), and EF (1.9). Consequently, simulating wound surfaces with moist environment using semisolid agar media, the APPJ allowed bactericidal treatment of highly contaminated surfaces of 55,cm2 imitating skin and wound colonization within 6,min. This antibacterial reduction power together with its handsome flexibility of the APPJ could be a suited therapeutic option in the therapy of infected or colonized wounds. [source] Re-osseointegration on previously contaminated surfaces: a systematic reviewCLINICAL ORAL IMPLANTS RESEARCH, Issue 2009Stefan Renvert Abstract Objectives: The aim of this review was to search the literature for the existing evidence of re-osseointegration after treatment of peri-implantitis at contaminated implant surfaces. Material and Methods: A search of PubMed as well as additional hand search of articles were conducted. Publications and articles accepted for publication up to November 2008 were included. Results: A total of 25 animal studies fulfilled the inclusion criteria for this review. Access surgery with closed healing has been observed to positively influence the rate of re-osseointegration when compared with non-surgical decontamination of the implant surface with open healing. Open debridement including surface decontamination may result in re-osseointegration and this integration was more pronounced on rougher than on smooth implant surfaces. The adjunctive use of regenerative procedures resulted in varying amounts of re-osseointegration. Conclusions: Re-osseointegration is possible to obtain on a previously contaminated implant surface and can occur in experimentally induced peri-implantitis defects following therapy. The amount of re-osseointegration, varied considerably within and between studies. Implant surface characteristics may influence the degree of re-osseointegration. Surface decontamination alone can not achieve substantial re-osseointegration on a previously contaminated implant surface. No method predictably accomplished complete resolution of the peri-implant defect. [source] | ||||||||||