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Sample records for radiation disinfected dates

  1. Enhanced compositing of radiation disinfected sewage sludge

    Science.gov (United States)

    Kawakami, W.; Hashimoto, S.

    Studies on isothermal composting of radiation disinfected sewage sludge and liquid chromatography of water extracts of the products were carried out. The optimum temperature and pH were around 50 °C and 7-8, respectively. The repeated use of products as seeds increased the rate of CO 2 evolution. The rate reached a maximum within 10 hours and decreased rapidly, and the CO 2 evolution ceased after about 3 days. The conversion of organic carbon to carbon dioxide attained to about 40% for the repeated use of products as seeds at the optimum conditions. As long as seeds in available were used, no remarkable difference was found in the composting of unirradiated and irradiated sludges. The composting process using radiation, however, can be carried out at the optimum conditions and is expected to shorten the composting period, because it is not necessary to keep fermentation temperature higher to reduce pathogen in sludge. Liquid chromatographic studies of the products showed that low molecular components decreased and higher molecular ones increased with fermentation. An index expressing the degree of reduction of easily decomposable organics was presented. The index also showed that the optimum temperature for fermentation was 50 °C, and that the easily decomposable organics disappeared above 30% of the conversion of organic carbon.

  2. Evaluation of the effectiveness of solar radiation for the disinfection ...

    African Journals Online (AJOL)

    The aim of the study was to evaluate the effectiveness of solar radiation as a disinfection agent for EPEC contaminated water. Effectiveness of SODIS was determined using viable coliform counts on VRBA medium and inactivation was determined by a reduction in growth of the organisms. The results show that it is possible ...

  3. Role of radiation dating technique - one example

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Etchevarne, Carlos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Filosofia e Ciencias Humanas. Dept. Antropologia e Etnologia; Cano, Nilo F.; Munita, C.S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-07-01

    Full text: The great majority of archaeological or geological dating technique is based on radiation effect. The so called radioactivity method uses radioactive decays of elements. This is the case of the well known radiocarbon or carbon-14 method. Also the method of relating daughter nucleus to decaying nucleus, as in K-40/Ar-40, Th- 230/U-234, etc. Here we will concentrate in the method based on energy deposition in a solid by radiation from the disintegration of U-series and Th-series. {beta}-rays emitted by the decay of K-40 into Ca-40 (80%) and Ar-40 (11%) also contributes. The role of {alpha}, {beta} and {gamma} radiation emitted by radionuclides in the U-238 and Th-232 series and of {beta} rays from the decay of K-40, all of them in the soil irradiate anything in their course. For dating, we can have sediments as well as potteries produced by ancient people and became buried. The important process consists in transferring a fraction of the energy of radiation to the solid, mainly liberating electrons from valence band to conduction band and from there to traps. In many case the energy of the radiation is used to create defects which in turn create energy levels (traps) in the forbidden gap (or energy gap). There are three ways to recover the energy stored in the solid: (1) by emission of light optically stimulated (OSL), (2) by emission of light thermally stimulated (TL), (3) by microwave absorption (EPR or ESR). Using these techniques among several applications, we will present one to find the first settlers in the northeaster region of Brazil. (author)

  4. Differential toxicity of drinking water disinfected with combinations of ultraviolet radiation and chlorine.

    Science.gov (United States)

    Plewa, Michael J; Wagner, Elizabeth D; Metz, Deborah H; Kashinkunti, Ramesh; Jamriska, Katherine J; Meyer, Maria

    2012-07-17

    Alternative technologies to disinfect drinking water such as ultraviolet (UV) disinfection are becoming more widespread. The benefits of UV disinfection include reduced risk of microbial pathogens such as Cryptosporidium and reduced production of regulated drinking water disinfection byproducts (DBPs). The objective of this research was to determine if mammalian cell cytotoxicity and genotoxicity varied in response to different chlorination protocols with and without polychromatic medium pressure UV (MPUV) and monochromatic low pressure UV (LPUV) disinfection technologies. The specific aims were to analyze the mammalian cell cytotoxicity and genotoxicity of concentrated organic fractions from source water before and after chlorination and to determine the cytotoxicity and genotoxicity of the concentrated organic fractions from water samples treated with UV alone or UV before or after chlorination. Exposure of granular activated carbon-filtered Ohio River water to UV alone resulted in the lowest levels of mammalian cell cytotoxicity and genotoxicity. With combinations of UV and chlorine, the lowest levels of cytotoxicity and genotoxicity were observed with MPUV radiation. The best combined UV plus chlorine methodology that generated the lowest cytotoxicity and genotoxicity employed chlorination first followed by MPUV radiation. These data may prove important in the development of multibarrier methods of pathogen inactivation of drinking water, while limiting unintended toxic consequences.

  5. Efficiency in the disinfection of water for human consumption in rural communities using solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Dominguez, A. [Instituto de Investigaciones Electricas, Mor (Mexico); Alarcon-Herrera, M.T.; Martin-Dominguez, I.R. [Centtro de Investigacion en Materiales Avanzados, Chih (Mexico); Gonzalez-Herrera, A. [Instituto Mexicano de Tecnologia del Agua, Mor (Mexico)

    2005-01-01

    The efficiency of solar disinfection for the inactivation of Total Coliforms (TC) and Escherichia coli (EC) in drinking water was tested in rural communities of the Guachochi Municipality, in the Tarahumara Sierra, State of Chihuahua, Mexico. The study zone was selected mostly because it lacks formal water supply systems and the population is forced to consume untreated water directly from rivers and shallow or artesian wells without treatment. To determine the bacteriological quality of the water consumed by the population, the amount of TC and EC in the water supplies of 23 communities in the studied municipality was determined. The efficiency of the solar energy based water disinfection process was determined for several months of the humid and dry seasons with water from the most contaminated sources of the study zone. The performed tests consisted in studying the effect of disinfecting water by direct exposure to sunlight during the whole day, with and without solar concentrators, in plastic bottles of commercial beverages. The three types of bottles used were transparent, partially painted black (one half of the bottle, along the longitudinal axis), and totally black. The study shows that, in this geographic zone, the available water must be disinfected before consumption and disinfection efficiency can reach 100% through the use of solar radiation. It was found that, since more than 6 h of daily solar radiation are available during most of the year in this zone, no solar concentrators are really necessary to ensure the complete elimination of bacteria. A complete disinfection takes place by simply placing water bottles in the sunlight during the whole day. Nevertheless, the use of solar concentrators and bottles partially painted black increases the TC and EC inactivation efficiency, reducing the solar exposure time required for a total disinfection to just 2 h. With the use of solar concentrators and partially blackened bottles, the water temperature

  6. Fluence Rate in UV Photoreactor for Disinfection of Water: Isotropically Radiating Cylinder

    Directory of Open Access Journals (Sweden)

    Roman Ilinsky

    2014-01-01

    Full Text Available The calculation of fluence rate in the photochemical reactor using ultraviolet (UV radiation for disinfection of water for the case, when a cylinder of infinite length is used as a light source, has been considered. Such a cylinder is filled with an isotropically radiating medium. The dependence of the fluent rate on the diameter of the radiating cylinder has been analytically analyzed. The limiting case when the diameter of the radiating cylinder tends to zero has been considered and the notion of “effective interval” has been introduced. Based on this notion, the comparison of fluence rates for the cylinders of finite and infinite lengths has been performed. In the calculations of fluence rate, it is advisable to use the Chebyshev method for the operations of numerical integration.

  7. Disinfection and reduction of organic load of sewage water by electron beam radiation

    Science.gov (United States)

    Maruthi, Y. Avasn; Das, N. Lakshmana; Hossain, Kaizar; Sarma, K. S. S.; Rawat, K. P.; Sabharwal, S.

    2011-09-01

    The efficacy of electron beam radiation for the disinfection and reduction of organic load of sewage water was assessed with ILU-6 Accelerator at Radiation Technology Development Division of the Bhabha Atomic Research Centre, Mumbai India. The current problem on environmental health in relation to water pollution insists for the safe disposal of sewage water. In general, sewage water comprises heterogeneous organic based chemicals as well as pathogens. EB treatment of the wastewater has found to be very effective in reducing the pathogens as well as organic load. EB dose of 1.5 kGy was sufficient for complete elimination of total coli forms. The experimental results elucidated the reduction of biological oxygen demand—BOD (35 and 51.7%) in both inlet and outlet sewage samples. Similarly reduction of chemical oxygen demand—COD was observed (37.54 and 52.32%) in both sewage samples with respect to increase in irradiation doses (0.45-6 kGy). The present study demonstrated the potential of ionizing radiation for disinfection of sewage and to increase the water quality of the wastewater by decreasing BOD and COD. So, the irradiation sewage water can find its application either in agriculture for irrigation, in industry for cooling purpose and some selected domestic purposes.

  8. Dating method of Jomon pottery by utilizing natural radiation

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Masahiko; Inokoshi, Yukio; Kitahara, Akiharu; Tanizaki, Yoshiyuki [Tokyo Metropolitan Isotope Research Center (Japan); Kamijo, Tomohiro

    1997-03-01

    ESR (Electron Spin Resonance) dating method using the signal induced by natural radiation was applied for the dating of Japanese prehistoric Pottery in TAMA Hill. About 100 mg of quartz was obtained from the shred of Pottery and ESR signal of Al center was observed. The obtained age of the pottery was older than that obtained from the charcoal excavated from the same site of the pottery by {sup 14}C method. The depth dependence of natural radiation ({gamma}-ray and cosmic ray) was measured by TLD (Thermoluminescence Dosimetry). At the depth less than 80 cm, the annual dose was somewhat more by the effect of cosmic ray than those at the depth more than 80 cm. Another dating method to measure the ESR signal of the quartz in the volcanic ash layer of Jomon period was examined. The obtained signal was too big to indicate Jomon age. Although the error is somewhat large, ESR dating method is concluded to be applicable for prehistoric pottery. (author)

  9. Advanced Treatment of Wastewater from UASB Reactor by Microfiltration Membrane Associated With Disinfection by Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    André Aguiar Battistelli

    2016-03-01

    Full Text Available The low efficiency of UASB bioreactors, regarding the removal of nutrient, organic matter and pathogens, makes it necessary to carry out a post treatment, in order to improve the quality of the effluent. Accordingly, this research has examined the use of microfiltration associated to the disinfection by the ultraviolet radiation, as an option to this post treatment. For so, were collected samples of UASB reactors’ effluent, in order to carry out some tests on a pilot microfiltration system, using in one of the samples pre-coagulation with vegetable tannin. After, all the microfiltrated samples were inserted in a UV reactor, applying different radiation doses, ranging from 43.8 to 194.9 mWs.cm-2, to simulate the disinfection. The system used showed good results in terms of turbidity removal, apparent color, true color, phosphorus, nitrogen, total solids, total suspended solids and COD, reaching in the best operating condition, the following values: 1.90 uT, 15 uC, 10 uC, 0.94 mg/L, 17.64 mg/L, 123 mg/L, 0 mg/L and 10 mg/L, respectively, which represent the following removal percentages: 91.3%, 93.6%, 82.0%, 55.1%, 26.3%, 35% and 86.1%. The inactivation obtained for E. coli, total coliforms, colifagos and Clostridium perfrigens was satisfactory, achieving a higher inactivation than the detection limit of the method used, when submitted to the highests tested radiation doses. The average permeate flux ranged from 55.2 to 133.6 L.m-2.h-1.

  10. Age of cichlids: new dates for ancient lake fish radiations.

    Science.gov (United States)

    Genner, Martin J; Seehausen, Ole; Lunt, David H; Joyce, Domino A; Shaw, Paul W; Carvalho, Gary R; Turner, George F

    2007-05-01

    Timing divergence events allow us to infer the conditions under which biodiversity has evolved and gain important insights into the mechanisms driving evolution. Cichlid fishes are a model system for studying speciation and adaptive radiation, yet, we have lacked reliable timescales for their evolution. Phylogenetic reconstructions are consistent with cichlid origins prior to Gondwanan landmass fragmentation 121-165 MYA, considerably earlier than the first known fossil cichlids (Eocene). We examined the timing of cichlid evolution using a relaxed molecular clock calibrated with geological estimates for the ages of 1) Gondwanan fragmentation and 2) cichlid fossils. Timescales of cichlid evolution derived from fossil-dated phylogenies of other bony fishes most closely matched those suggested by Gondwanan breakup calibrations, suggesting the Eocene origins and marine dispersal implied by the cichlid fossil record may be due to its incompleteness. Using Gondwanan calibrations, we found accumulation of genetic diversity within the radiating lineages of the African Lakes Malawi, Victoria and Barombi Mbo, and Palaeolake Makgadikgadi began around or after the time of lake basin formation. These calibrations also suggest Lake Tanganyika was colonized independently by the major radiating cichlid tribes that then began to accumulate genetic diversity thereafter. These results contrast with the widely accepted theory that diversification into major lineages took place within the Tanganyika basin. Together, this evidence suggests that ancient lake habitats have played a key role in generating and maintaining diversity within radiating lineages and also that lakes may have captured preexisting cichlid diversity from multiple sources from which adaptive radiations have evolved.

  11. Water disinfection with solar radiation; Desinfeccion del agua con radiacion solar

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Alejandra; Cortes, Juana E; Rodriguez, Miriam; Mundo, Alfredo; Vazquez, Sandra [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico); Estrada, Claudio A [Centro de Investigacion en Energia, Temixco, Morelos (Mexico)

    2000-07-01

    Water disinfection by exposure to solar radiation is a low cost and easy application option to rural communities. The treatment of water can be done using plastic bags or plastic bottles of two litters setting on a reflective material. The efficient of the plastic bottles is lower than the one plastic bags, but the plastic bottles have a much better control of the treated water avoiding its recontamination. In order to increase the efficiency of disinfection using plastic bottles, two solar concentrators, using flat mirrors, were designed and built. Effluent water from a treatment plant of residual waters was used for the testing. Several comparison were carried out taking into account the position of the concentrators, the transparency of the bottles and the bags. The results show that using the concentrator that adjust its position to the sun every hour, a 100% disinfection is obtained in 4 hours of direct exposure to the sun rays in a sunny day. The period of time can be reduced up to 2 hours, if instead using transparent bottles, the bottles are black painted at their bottom half. With these results, the basis to design a cheap concentrator of easy construction to be used in rural communities have been settle. [Spanish] La desinfeccion del agua por exposicion a la luz solar fotodesinfeccion es una opcion de bajo costo y facil aplicacion para las comunidades rurales. El tratamiento puede llevarse a cabo utilizando bolsas o botellas de plastico transparente de dos litros de capacidad colocadas sobre un material reflejante. Las botellas son menos eficientes que las bolsas, pero permiten un mejor control del agua tratada evitando su recontaminacion. Para aumentar la eficiencia de la desinfeccion utilizando las botellas, se disenaron y construyeron dos concentradores solares de espejos planos que permitieron disminuir el tiempo de exposicion requerido cuando se utilizan estas. Para las pruebas de desinfeccion se utilizo agua del efluente de una planta de tratamiento

  12. Effect of radiation on disinfection and mechanical properties of Korean traditional paper, Hanji

    Science.gov (United States)

    Choi, Jong-il; Chung, Yong Jae; Kang, Dai Ill; Lee, Kyu Shik; Lee, Ju-Woon

    2012-08-01

    Fumigants, including methyl bromide and ethylene oxide, are generally used for the preservation of the Korean cultural heritage, especially paper products like letters and books. However, the use of fumigants is banned because of their harmful effects on humans and the environment. Gamma irradiation is being considered as an alternative for the sterilization of insects and fungi in organic products. Therefore, the purpose of this study was to investigate the sterilization effects of radiation and its effect on the mechanical properties of the Korean traditional paper—Hanji. Treatment doses of 9 kGy and 8 kGy of gamma irradiation inactivated 5 log units of Aspergillus niger and Bacillus cereus spores inoculated on Hanji, respectively. The gamma irradiations up to an absorbed dose of 50 kGy resulted in no significant changes in the tensile strength, bursting strength, and appearance of Hanji. These results confirmed that radiation treatment disinfects the Korean traditional paper efficiently without changing its properties and that this treatment could be used to prevent the damage of Korean ancient archives by molds and fungi.

  13. Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV

    Directory of Open Access Journals (Sweden)

    Jeanette Beber de Souza

    2015-01-01

    Full Text Available The individual methods of disinfection peracetic acid (PAA and UV radiation and combined process PAA/UV in water (synthetic and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater, and coliphages (such as virus indicators. Under the experimental conditions investigated, doses of 2, 3, and 4 mg/L of PAA and contact time of 10 minutes and 60 and 90 s exposure to UV radiation, the results indicated that the combined method PAA/UV provided superior efficacy when compared to individual methods of disinfection.

  14. Solar radiation disinfection of drinking water at temperate latitudes: inactivation rates for an optimised reactor configuration.

    Science.gov (United States)

    Davies, C M; Roser, D J; Feitz, A J; Ashbolt, N J

    2009-02-01

    Solar radiation-driven inactivation of bacteria, virus and protozoan pathogen models was quantified in simulated drinking water at a temperate latitude (34 degrees S). The water was seeded with Enterococcus faecalis, Clostridium sporogenes spores, and P22 bacteriophage, each at ca 1x10(5) mL(-1), and exposed to natural sunlight in 30-L reaction vessels. Water temperature ranged from 17 to 39 degrees C during the experiments lasting up to 6h. Dark controls showed little inactivation and so it was concluded that the inactivation observed was primarily driven by non-thermal processes. The optimised reactor design achieved S90 values (cumulative exposure required for 90% reduction) for the test microorganisms in the range 0.63-1.82 MJ m(-2) of Global Solar Exposure (GSX) without the need for TiO2 as a catalyst. High turbidity (840-920 NTU) only reduced the S(90) value by 0.05). However, inactivation was significantly reduced for E. faecalis and P22 when the transmittance of UV wavelengths was attenuated by water with high colour (140 PtCo units) or a suboptimally transparent reactor lid (prob.SODIS type pasteurization were not produced, non-thermal inactivation alone appeared to offer a viable means for reliably disinfecting low colour source waters by greater than 4 orders of magnitude on sunny days at 34 degrees S latitude.

  15. Disinfection of an advanced primary effluent using peracetic acid or ultraviolet radiation for its reuse in public services.

    Science.gov (United States)

    Julio, Flores R; Hilario, Terres-Peña; Mabel, Vaca M; Raymundo, López C; Arturo, Lizardi-Ramos; Ma Neftalí, Rojas-Valencia

    2015-03-01

    The disinfection of a continuous flow of an effluent from an advanced primary treatment (coagulation-flocculation-sedimentation) with or without posterior filtration, using either peracetic acid (PAA) or ultraviolet (UV) radiation was studied. We aimed to obtain bacteriological quality to comply with the microbiological standard established in the Mexican regulations for treated wastewater reuse (NOM-003-SEMARNAT-1997), i.e., less than 240 MPN (most probable number) FC/100 mL. The concentrations of PAA were 10, 15, and 20 mg/L, with contact times of 10, and 15 min. Fecal coliforms (FC) inactivation ranged from 0.93 up to 6.4 log units, and in all cases it reached the limits set by the mentioned regulation. Water quality influenced the PAA disinfection effectiveness. An efficiency of 91% was achieved for the unfiltered effluent, as compared to 99% when wastewater was filtered. UV radiation was applied to wastewater flows of 21, 30 and 39 L/min, with dosages from 1 to 6 mJ/cm². This treatment did not achieve the bacteriological quality required for treated wastewater reuse, since the best inactivation of FC was 1.62 log units, for a flow of 21 L/min of filtered wastewater and a UV dosage of 5.6 mJ/cm².

  16. Micro-organism re-growth in wastewater disinfected by UV radiation and ozone: a micro-biological study.

    Science.gov (United States)

    Alonso, E; Santos, A; Riesco, P

    2004-04-01

    A series of disinfection experiments using UV radiation and ozone was performed on the secondary effluent from a wastewater treatment plant at a pilot plant scale. The microbial population in the inflowing wastewater and the treated outflow water were quantified for each of the treatment modules (fecal coliforms, fecal streptococci, Salmonella spp. (presence/absence), Clostridium Sulphite-reducers, Pseudomonas aeruginosa, Staphylococcus aureus, coliphages, nematodes, intestinal nematodes and pathogenic fungi). Treated water was stored in opaque tanks at a temperature between 20 and 22 degrees C, after which, a one-month study of the regrowth of the bacterial flora, nematodes and fungi was carried out. Clostridium Sulphite-reducers, pathogenic fungi and nematodes were the micro-organisms showing a greatest degree of resistence to UV- and Ozone-treatment. It was only concerning Clostridium and Pseudomonas abatement that significant elimination results were achieved with both technologies.

  17. Isolation of Bacillus subtilis as indicator in the disinfection of residual water by means of gamma radiation; Aislamiento de Bacillus subtilis como indicador en la desinfeccion de aguas residuales mediante radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Mata J, M.; Colin C, A. [Facultad de Quimica, UAEM, Paseo Colon esq. Tollocan s/n, Toluca, 50000 Estado de Mexico (Mexico); Lopez V, H.; Brena V, M.; Carrasco A, H.; Pavon R, S. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    In the attempt to get more alternatives of disinfection of residual water, the Bacillus subtilis was isolated by means of gamma radiation as a bio indicator of disinfection since it turned out to be resistant to the 5 KGy dose, comparing this one with other usual microorganisms as biondicators like E. coli and S typhimurium which turn out more sensitive to such dose. (Author)

  18. Disinfection process of municipal wastewater through ultraviolet radiation: Application in the wastewater treatment plant of Jerez de la Frontera; Desinfeccion de aguas residuales urbanas mediante radiacion ultravioleta: Aplicacion enla EDAR de Jerez de la Frontera

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo Davila, I.; Andrades Balao, J. A.; Quiroga Alonso, J. M.

    2002-07-01

    This paper reports the results obtained of the disinfection through ultraviolet radiation of the treated municipal wastewater in the plant of Jerez de la Frontera for possible municipal and tourist/recreational reuse. The results obtained show that 1.265 J/m''2 of UV doses cause nearly a 99, 9% decrease of the studied microorganisms (total coliform, fecal coliform and fecal strepto cocos) in more than 77% of the carried out studies. The disinfection unitary cost, at industrial scale, was 0.03 E/m''3 waste-water, which means the UV radiation treatment is very competitive against others disinfection systems. (Author) 10 refs.

  19. Effect of peracetic acid, ultraviolet radiation, nanofiltration-chlorine in the disinfection of a non conventional source of water (Tula Valley).

    Science.gov (United States)

    Trujillo, J; Barrios, J A; Jimenez, B

    2008-01-01

    Water supply for human consumption requires certain quality that reduces health risks to consumers. In this sense, the process of disinfection plays an important role in the elimination of pathogenic microorganisms. Even though chlorination is the most applied process based on its effectiveness and cost, its application is being questioned considering the formation of disinfection by-products (DBPs). Therefore, alternative disinfectants are being evaluated and some treatment processes have been proposed to remove DBPs precursors (organic matter. This paper reports the results of disinfection of a non conventional source of water (aquifer recharged unintentionally with raw wastewater) with peracetic acid (PAA) and ultraviolet radiation (UV) as well as nanofiltration (NF) followed by chlorination to produce safe drinking water. The results showed that a dose of 2 mg/L PAA was needed to eliminate total and faecal coliforms. For UV light, a dose of 12.40 mWs/cm2 reduced total and faecal coliforms below the detection limit. On the other hand, chlorine demand of water before NF was 1.1-1.3 mg/L with a trihalomethane formation potential (THMFP) of 118.62 microg/L, in contrast with chlorination after NF where the demand was 0.5 mg/L and THMFP of 17.64 microg/L. The recommended scheme is nanofiltration + chlorination.

  20. Disinfection of drain water of tomato by means of UV radiation and slow sand filtration in real greenhouse circumstances.

    Science.gov (United States)

    De Rocker, E; Goen, K; Van Poucke, K

    2006-01-01

    The efficiency of the disinfection of drain water was tested at 11 greenhouses with tomato cultivation on rockwool substrate in Flanders (Belgium) by means of mycological analysis. In addition the presence of phytopathogenic fungi in the drain water was analysed at 2 supplementary greenhouses with recirculation without disinfection.

  1. Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight

    Science.gov (United States)

    2012-07-01

    dehydration and oxygenation may also contribute to the increased vulnerability of airborne microbes. This report provides background and...Coohill and Sagripanti, 2009). The germicidal effect of solar radiation has been known for many years and was described as early as 1878 (Black and...latitude, altitude, solar zenith angle (the angle between the sun and zenith during the day), the day of the year, and weather conditions (Lytle and

  2. Plant-insect interactions: double-dating associated insect and plant lineages reveals asynchronous radiations.

    Science.gov (United States)

    Percy, Diana M; Page, Roderic D M; Cronk, Quentin C B

    2004-02-01

    An increasing number of plant-insect studies using phylogenetic analysis suggest that cospeciation events are rare in plant-insect systems. Instead, nonrandom patterns of phylogenetic congruence are produced by phylogenetically conserved host switching (to related plants) or tracking of particular resources or traits (e.g., chemical). The dominance of host switching in many phytophagous insect groups may make the detection of genuine cospeciation events difficult. One important test of putative cospeciation events is to verify whether reciprocal speciation is temporally plausible. We explored techniques for double-dating of both plant and insect phylogenies. We use dated molecular phylogenies of a psyllid (Hemiptera)-Genisteae (Fabaceae) system, a predominantly monophagous insect-plant association widespread on the Atlantic Macaronesian islands. Phylogenetic reconciliation analysis suggests high levels of parallel cladogenesis between legumes and psyllids. However, dating using molecular clocks calibrated on known geological ages of the Macaronesian islands revealed that the legume and psyllid radiations were not contemporaneous but sequential. Whereas the main plant radiation occurred some 8 million years ago, the insect radiation occurred about 3 million years ago. We estimated that >60% of the psyllid speciation has resulted from host switching between related hosts. The only evidence for true cospeciation is in the much more recent and localized radiation of genistoid legumes in the Canary Islands, where the psyllid and legume radiations have been partially contemporaneous. The identification of specific cospeciation events over this time period, however, is hindered by the phylogenetic uncertainty in both legume and psyllid phylogenies due to the apparent rapidity of the species radiations.

  3. Effect of the radiation intensity, water turbidity and exposure time on the survival of Cryptosporidium during simulated solar disinfection of drinking water.

    Science.gov (United States)

    Gómez-Couso, Hipólito; Fontán-Sainz, María; McGuigan, Kevin G; Ares-Mazás, Elvira

    2009-10-01

    The solar disinfection (SODIS) technique is a highly effective process that makes use of solar energy to inactivate pathogenic microorganisms in drinking water in developing countries. The pathogenic protozoan parasite Cryptosporidium parvum is often found in surface waters and is associated with waterborne outbreaks of cryptosporidiosis. In the present study, a complete multi-factorial mathematical model was used to investigate the combined effects of the intensity of solar radiation (200, 600 and 900W/m(2) in the 320nm to 10microm range), water turbidity (5, 100 and 300 NTU) and exposure time (4, 8 and 12h) on the viability and infectivity of C. parvum oocysts during simulated SODIS procedures at a constant temperature of 30 degrees C. All three factors had significant effects (p or =600W/m(2) and times of exposure between 8 and 12h were required to reduce the oocyst infectivity in water samples with different degrees of turbidity.

  4. Bayesian Total-Evidence Dating Reveals the Recent Crown Radiation of Penguins.

    Science.gov (United States)

    Gavryushkina, Alexandra; Heath, Tracy A; Ksepka, Daniel T; Stadler, Tanja; Welch, David; Drummond, Alexei J

    2017-01-01

    The total-evidence approach to divergence time dating uses molecular and morphological data from extant and fossil species to infer phylogenetic relationships, species divergence times, and macroevolutionary parameters in a single coherent framework. Current model-based implementations of this approach lack an appropriate model for the tree describing the diversification and fossilization process and can produce estimates that lead to erroneous conclusions. We address this shortcoming by providing a total-evidence method implemented in a Bayesian framework. This approach uses a mechanistic tree prior to describe the underlying diversification process that generated the tree of extant and fossil taxa. Previous attempts to apply the total-evidence approach have used tree priors that do not account for the possibility that fossil samples may be direct ancestors of other samples, that is, ancestors of fossil or extant species or of clades. The fossilized birth–death (FBD) process explicitly models the diversification, fossilization, and sampling processes and naturally allows for sampled ancestors. This model was recently applied to estimate divergence times based on molecular data and fossil occurrence dates. We incorporate the FBD model and a model of morphological trait evolution into a Bayesian total-evidence approach to dating species phylogenies. We apply this method to extant and fossil penguins and show that the modern penguins radiated much more recently than has been previously estimated, with the basal divergence in the crown clade occurring at ∼12.7 ∼12.7 Ma and most splits leading to extant species occurring in the last 2 myr. Our results demonstrate that including stem-fossil diversity can greatly improve the estimates of the divergence times of crown taxa. The method is available in BEAST2 (version 2.4) software www.beast2.org with packages SA (version at least 1.1.4) and morph-models (version at least 1.0.4) installed.

  5. Proton Radiation Therapy for Head and Neck Cancer: A Review of the Clinical Experience to Date

    Energy Technology Data Exchange (ETDEWEB)

    Holliday, Emma B.; Frank, Steven J., E-mail: sjfrank@mdanderson.org

    2014-06-01

    Proton beam radiation has been used for cancer treatment since the 1950s, but recent increasing interest in this form of therapy and the construction of hospital-based and clinic-based facilities for its delivery have greatly increased both the number of patients and the variety of tumors being treated with proton therapy. The mass of proton particles and their unique physical properties (ie, the Bragg peak) allow proton therapy to spare normal tissues distal to the tumor target from incidental irradiation. Initial observations show that proton therapy is particularly useful for treating tumors in challenging locations close to nontarget critical structures. Specifically, improvements in local control outcomes for patients with chordoma, chonodrosarcoma, and tumors in the sinonasal regions have been reported in series using proton. Improved local control and survival outcomes for patients with cancer of the head and neck region have also been seen with the advent of improvements in better imaging and multimodality therapy comprising surgery, radiation therapy, and chemotherapy. However, aggressive local therapy in the proximity of critical normal structures to tumors in the head and neck region may produce debilitating early and late toxic effects. Great interest has been expressed in evaluating whether proton therapy can improve outcomes, especially early and late toxicity, when used in the treatment of head and neck malignancies. This review summarizes the progress made to date in addressing this question.

  6. [Disinfection for cistern water].

    Science.gov (United States)

    Ling, B; Han, G G; Shi, N; Shang, Q

    2001-03-01

    Rainwater is often collected into cisterns (pits or tanks) for household using as drinking water source in the rural areas of the northwest and the southeast coast in China, where no enough fresh water resource is available. However, the total number of bacteria and coliforms in the cisterns water was higher than the standard of that in drinking water. In order to ensure the safety for drinking, the effectiveness, conditions of treatment and cost for such disinfection methods compared with solar radiation, ultraviolet (UV), chloridation, micro-filteration and KDF were studied in 10 households in Cixi of Zhejiang Province and Weiyuan of Gansu Provinces, respectively. The micro-filteration is more compatible for bacteria removal in the tanks, while chloridation more for disinfection in the underground pits.

  7. Bayesian Total-Evidence Dating Reveals the Recent Crown Radiation of Penguins

    Science.gov (United States)

    Heath, Tracy A.; Ksepka, Daniel T.; Stadler, Tanja; Welch, David; Drummond, Alexei J.

    2017-01-01

    The total-evidence approach to divergence time dating uses molecular and morphological data from extant and fossil species to infer phylogenetic relationships, species divergence times, and macroevolutionary parameters in a single coherent framework. Current model-based implementations of this approach lack an appropriate model for the tree describing the diversification and fossilization process and can produce estimates that lead to erroneous conclusions. We address this shortcoming by providing a total-evidence method implemented in a Bayesian framework. This approach uses a mechanistic tree prior to describe the underlying diversification process that generated the tree of extant and fossil taxa. Previous attempts to apply the total-evidence approach have used tree priors that do not account for the possibility that fossil samples may be direct ancestors of other samples, that is, ancestors of fossil or extant species or of clades. The fossilized birth–death (FBD) process explicitly models the diversification, fossilization, and sampling processes and naturally allows for sampled ancestors. This model was recently applied to estimate divergence times based on molecular data and fossil occurrence dates. We incorporate the FBD model and a model of morphological trait evolution into a Bayesian total-evidence approach to dating species phylogenies. We apply this method to extant and fossil penguins and show that the modern penguins radiated much more recently than has been previously estimated, with the basal divergence in the crown clade occurring at \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${\\sim}12.7$\\end{document} Ma and most splits leading to extant species occurring in the last 2 myr. Our results demonstrate that including stem-fossil diversity can greatly

  8. Solar disinfection (SODIS): simulation of solar radiation for global assessment and application for point-of-use water treatment in Haiti.

    Science.gov (United States)

    Oates, Peter M; Shanahan, Peter; Polz, Martin F

    2003-01-01

    Haiti and other developing countries do not have sufficient meteorological data to evaluate if they meet the solar disinfection (SODIS) threshold of 3-5 h of solar radiation above 500 W/m2, which is required for adequate microbial inactivation in drinking water. We have developed a mathematical model based on satellite-derived daily total energies to simulate monthly mean, minimum, and maximum 5-h averaged peak solar radiation intensities. This model can be used to assess if SODIS technology would be applicable anywhere in the world. Field measurements were made in Haiti during January 2001 to evaluate the model and test SODIS efficacy as a point-of-use treatment option. Using the total energy from a measured solar radiation intensity profile, the model recreated the intensity profile with 99% agreement. NASA satellite data were then used to simulate the mean, minimum, and maximum 5-h averaged peak intensities for Haiti in January, which were within 98.5%, 62.5%, and 86.0% agreement with the measured values, respectively. Most of the discrepancy was attributed to the heterogeneous nature of Haiti's terrain and the spatial resolution of the NASA data. Additional model simulations suggest that SODIS should be effective year-round in Haiti. Actual SODIS efficacy in January was tested by the inactivation of total coliform, E. coli, and H2S-producing bacteria. Exposure period proved critical. One-day exposure achieved complete bacterial inactivation 52% of the time, while a 2-day exposure period achieved complete microbial inactivation 100% of the time. A practical way of providing people with cold water every morning that has undergone a 2-day exposure would be to rotate three groups of bottles every morning, so two groups are out in the sun and one is being used for consumption.

  9. Desinfecção de água de chuva por radiação ultravioleta Disinfection of rainwater by ultraviolet radiation

    Directory of Open Access Journals (Sweden)

    Elisabeth Wisbeck

    2011-12-01

    Full Text Available O objetivo deste trabalho foi avaliar o tratamento de água de chuva, de duas regiões industriais de Joinville (SC, por radiação ultravioleta. O reator operou em processo contínuo, de modo que cada partícula permanecesse sob radiação por 60 segundos. As amostras de água foram analisadas em termos de coliformes totais, coliformes termotolerantes e bactérias heterotróficas antes do tratamento por ultravioleta, após o tratamento e após tratadas e armazenadas por 24, 48 e 72 horas. Verificou-se a eficiência da desinfecção de água de chuva direta e de telhado por radiação ultravioleta com a inativação de 100% dos coliformes totais e dos coliformes termotolerantes e o não recrescimento desses micro-organismos em amostras tratadas e estocados por até 72 horas, no entanto, bactérias heterotróficas persistiram e foram identificadas após 24, 48 e 72 horas ao tratamento.The objective of this study was to evaluate the treatment of rainwater in two industrial regions in Joinville (SC, Brazil by ultraviolet radiation. The reactor was operating in continuous process with each particle remaining under radiation for 60 seconds. The samples were evaluated in terms of total coliforms, fecal coliform and heterotrophic bacteria prior to ultraviolet treatment, after treatment and further treated and stored for 24, 48 and 72 hours. The efficiency of disinfection of direct rainwater and that collected from roofing by ultraviolet radiation was verified with 100% inactivation of total coliforms and fecal coliform and these microorganisms did not reappear in samples treated and stored for up to 72 hours, however, heterotrophic bacteria persisted and were identified after 24, 48 and 72 hours of treatment.

  10. A total-evidence approach to dating with fossils, applied to the early radiation of the hymenoptera.

    Science.gov (United States)

    Ronquist, Fredrik; Klopfstein, Seraina; Vilhelmsen, Lars; Schulmeister, Susanne; Murray, Debra L; Rasnitsyn, Alexandr P

    2012-12-01

    Phylogenies are usually dated by calibrating interior nodes against the fossil record. This relies on indirect methods that, in the worst case, misrepresent the fossil information. Here, we contrast such node dating with an approach that includes fossils along with the extant taxa in a Bayesian total-evidence analysis. As a test case, we focus on the early radiation of the Hymenoptera, mostly documented by poorly preserved impression fossils that are difficult to place phylogenetically. Specifically, we compare node dating using nine calibration points derived from the fossil record with total-evidence dating based on 343 morphological characters scored for 45 fossil (4--20 complete) and 68 extant taxa. In both cases we use molecular data from seven markers (∼5 kb) for the extant taxa. Because it is difficult to model speciation, extinction, sampling, and fossil preservation realistically, we develop a simple uniform prior for clock trees with fossils, and we use relaxed clock models to accommodate rate variation across the tree. Despite considerable uncertainty in the placement of most fossils, we find that they contribute significantly to the estimation of divergence times in the total-evidence analysis. In particular, the posterior distributions on divergence times are less sensitive to prior assumptions and tend to be more precise than in node dating. The total-evidence analysis also shows that four of the seven Hymenoptera calibration points used in node dating are likely to be based on erroneous or doubtful assumptions about the fossil placement. With respect to the early radiation of Hymenoptera, our results suggest that the crown group dates back to the Carboniferous, ∼309 Ma (95% interval: 291--347 Ma), and diversified into major extant lineages much earlier than previously thought, well before the Triassic. [Bayesian inference; fossil dating; morphological evolution; relaxed clock; statistical phylogenetics.].

  11. Susceptibility of Vaccinia Virus to Chemical Disinfectants

    Science.gov (United States)

    de Oliveira, Tércia Moreira Ludolfo; Rehfeld, Izabelle Silva; Coelho Guedes, Maria Isabel Maldonado; Ferreira, Jaqueline Maria Siqueira; Kroon, Erna Geessien; Lobato, Zélia Inês Portela

    2011-01-01

    Vaccinia virus (VACV) is the cause of bovine vaccinia (BV), an emerging zoonotic disease that affects dairy cows and milkers. Some chemical disinfectants have been used on farms affected by BV to disinfect cow teats and milkers' hands. To date, there is no information about the efficacy of disinfectants against VACV. Therefore, this study aimed to assess the virucidal activity of some active disinfectants commonly used in the field. Sodium hypochlorite, quaternary ammonium combined with chlorhexidine, and quaternary ammonium combined with glutaraldehyde were effective in inactivating the virus at all concentrations tested. Iodine and quaternary ammonium as the only active component were partially effective. The presence of bovine feces as organic matter and light decreased the effectiveness of sodium hypochlorite. These results show that an appropriated disinfection and asepsis of teats and hands may be helpful in the control and prevention of BV and other infections with VACV. PMID:21734141

  12. ASTRO's Advances in Radiation Oncology: Success to date and future plans

    Directory of Open Access Journals (Sweden)

    Robert C. Miller, MD, MBA, FASTRO

    2017-07-01

    Full Text Available ASTRO's Advances in Radiation Oncology was launched as a new, peer-reviewed scientific journal in December 2015. More than 200 manuscripts have been submitted and 97 accepted for publication as of May 2017. As Advances enters its second year of publication, we have chosen to highlight subjects that will transform the way we practice radiation oncology in special issues or ongoing series: immunotherapy, biomedical analytics, and social media. A teaching case report contest for North American radiation oncology residents will be launched at American Society of Radiation Oncology 2017 to encourage participation in scientific publication by trainees early in their careers. Recognizing our social mission, Advances will also begin a series of articles devoted to highlighting the growing disparities in access to radiation oncology services in vulnerable populations in North America. We wish to encourage the American Society of Radiation Oncology membership to continue its support of the journal through high-quality manuscript submission, participation in the peer review process, and highlighting important manuscripts through sharing on social media.

  13. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, Noreddine

    2015-08-20

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

  14. The efficacy of potassium ferrate as a chemical disinfectant on E. coli, Vibrio cholera, human adenovirus, and Giardia lamblia

    Science.gov (United States)

    Introduction: Drinking water and wastewater go through numerous treatments to remove microorganisms and other contaminants one of many processes along the treatment train is disinfection. There are different ways to disinfect these waters, however to date the most common disinf...

  15. The efficacy of potassium ferrate as a chemical disinfectant on E. coli, Vibrio cholera, human adenovirus, and Giardia lamblia - Abstract

    Science.gov (United States)

    Introduction: Drinking water and wastewater effluents go through numerous treatments to remove microorganisms and other contaminants in the United States. One of many processes along the treatment train is disinfection, and to date the most common disinfectants still remain chemi...

  16. Deciphering and dating the red panda's ancestry and early adaptive radiation of Musteloidea.

    Science.gov (United States)

    Sato, Jun J; Wolsan, Mieczyslaw; Minami, Shinji; Hosoda, Tetsuji; Sinaga, Martua H; Hiyama, Kozue; Yamaguchi, Yasunori; Suzuki, Hitoshi

    2009-12-01

    information from all sampled genes yielded a approximately 42-Myr timescale to caniform evolution and provided evidence of five periods of increased diversification. The red panda's lineage and those of other extant musteloid families are estimated to have diverged during a 3-Myr interval from the mid-Early Oligocene to near the Early/Late Oligocene boundary. We present fossil evidence that extends the early adaptive radiation of the total clade of musteloids to the Eocene-Oligocene transition and also suggests Asia as a center of this radiation.

  17. Applications of Photocatalytic Disinfection

    Directory of Open Access Journals (Sweden)

    Joanne Gamage

    2010-01-01

    Full Text Available Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

  18. Intracellular mechanisms of solar water disinfection

    Science.gov (United States)

    Castro-Alférez, María; Polo-López, María Inmaculada; Fernández-Ibáñez, Pilar

    2016-12-01

    Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E. coli during solar irradiation. For this experimental achievement, a modified protocol based on the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA), widely used for oxidative stress in eukaryotic cells, has been tested and validated for E. coli. Our results demonstrate that ROS and their accumulated oxidative damages at intracellular level are key in solar water disinfection.

  19. Environmental cleaning and disinfection.

    Science.gov (United States)

    Traverse, Michelle; Aceto, Helen

    2015-03-01

    The guidelines in this article provide veterinarians, veterinary technicians, and veterinary health care workers with an overview of evidence-based recommendations for the best practices associated with environmental cleaning and disinfection of a veterinary clinic that deals with small animals. Hospital-associated infections and the control and prevention programs necessary to alleviate them are addressed from an environmental perspective. Measures of hospital cleaning and disinfection include understanding mechanisms and types of contamination in veterinary settings, recognizing areas of potential concern, addressing appropriate decontamination techniques and selection of disinfectants, the management of potentially contaminated equipment, laundry, and waste management, and environmental surveillance strategies. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Humidifier disinfectants, unfinished stories

    Directory of Open Access Journals (Sweden)

    Yeyong Choi

    2016-02-01

    Full Text Available Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

  1. Emergency Disinfection of Drinking Water

    Science.gov (United States)

    How to boil and disinfect water to kill most disease-causing microorganisms during emergency situations where regular water service has been interrupted and local authorities recommend using only bottled water, boiled water, or disinfected water.

  2. Environmental dose rate heterogeneity of beta radiation and its implications for luminescence dating: Monte Carlo modelling and experimental validation

    DEFF Research Database (Denmark)

    Nathan, R.P.; Thomas, P.J.; Jain, M.

    2003-01-01

    The recent development of rapid single sand-sized grain analyses in luminescence dating has necessitated the accurate interpretation of D-e distributions to recover a representative D-e acquired since the last bleaching event. Beta heterogeneity may adversely affect the variance and symmetry of D...... and identify the likely size of these effects on D-e distributions. The study employs the MCNP 4C Monte Carlo electron/photon transport model, supported by an experimental validation of the code in several case studies. We find good agreement between the experimental measurements and the Monte Carlo......-e distributions and it is important to characterise this effect, both to ensure that dose distributions are not misinterpreted, and that an accurate beta dose rate is employed in dating calculations. In this study, we make a first attempt providing a description of potential problems in heterogeneous environments...

  3. Water disinfection agents and disinfection by-products

    Science.gov (United States)

    Ilavský, J.; Barloková, D.; Kapusta, O.; Kunštek, M.

    2017-10-01

    The aim of this work is to describe factors of water quality change in the distribution network and legislative requirements in Slovakia for disinfectants and disinfection byproducts (DBPs). In the experimental part, the time dependence of the application of the chlorine dioxide and sodium hypochlorite on the formation of some by-products of disinfection for drinking water from WTP Hriňová is studied. We monitored trihalomethanes, free chlorine, chlorine dioxide and chlorites.

  4. Organ-confined prostate carcinoma radiation brachytherapy compared with external either photon- or hadron-beam radiation therapy. Just a short up-to-date.

    Science.gov (United States)

    Alberti, C

    2011-07-01

    Both low dose rate (LDR) permanent either 1251 or 103Pd seed implant and high dose rate (HDR) 1921r temporary implant are an excellent way to release high dose of ionizing radiations to cancerous lesions while significantly sparing the surrounding healthy tissues. Therefore, the radiation brachytherapy, among the established treatment options of organ-confined prostate carcinoma--interstitial radiofrequency, high intensity focused ultrasound, cryotherapy--has gained large acceptance in the last decades. The LDR permanent interstitial radioactive seed implantation is often used as monotherapy for low risk prostate carcinoma whereas the HDR temporary implant may useful to treat intermediate-to-high risk prostate tumors as a radiation boost to combined external beam radiation therapy (EBRT). On the other hand, with recent refinement of EBRT techniques--either three-dimensional conformal- or intensity-modulated radiotherapy, cyber-knife radiosurgery with even 4D-high resolution image-guided tracking--high doses of X-rays may be precisely delivered to prostate malignant lesions without increasing toxicity for surrounding normal structures. Also hadron therapy is an increasingly successful technique that allows the release of effective energy of protons (H+), neutrons or carbon ions (6(12)C) to the limited extent of the cancerous target site, thus destroying malignant lesion with millimetric precision--just as bloodless surgery--while less damaging the neighbouring healthy tissues. Looking to the near future, even more effective oncotherapy modality appears to be the use of antiprotons because of their highly confined energy deposition at well defined body dept around the annihilation point in contact with protons of the ordinary matter, so targeting only a very limited body volume.

  5. Comparing irradiation parameters on disinfecting enterrecoccus faecalis in root canal disinfection

    Science.gov (United States)

    Sarp, Ayşe. S.; Gülsoy, Murat

    2016-02-01

    Although conventional method carries all the debris, studies on persisting infections in root canals show bacteria and their toxins spread from the root canal and contaminate the apical region. Thus developes apical periodontitis or symptoms, and loss of tooth. Even if the treatment has adequate success, anatomy of root canal system can be very complexwith accessory canals. The disinfecting effect of laser radiation has only recently been used in dentistry. Laser irradiation has a bactericidal effect. Each wavelength has its own advantages and limitations according to their different absorption characteristics, depending on their 'absorption coefficient'. The sterilizing efficiency of two types of wavelengths, a new fiber laser 1940- nm Thulium fiber Laser and an 2940 nm Er:YAG Laser were compared in this study. Irradiation with a power of 0.50 W with 1940- nm Thulium fiber Laser disinfected 95,15% of bacteria, however irradiation with same laser power with Er:YAG Laser caused a reduction of 96,48 %. But there was no significant difference in the disinfection effect of two different laser groups ( p Laser caused three times more reduction from its own positive control group where 1940- nm Thulium fiber Laser caused 2,5 times effective disinfection.

  6. Disinfectant choices in veterinary practices, shelters and households: ABCD guidelines on safe and effective disinfection for feline environments.

    Science.gov (United States)

    Addie, Diane D; Boucraut-Baralon, Corine; Egberink, Herman; Frymus, Tadeusz; Gruffydd-Jones, Tim; Hartmann, Katrin; Horzinek, Marian C; Hosie, Margaret J; Lloret, Albert; Lutz, Hans; Marsilio, Fulvio; Pennisi, Maria Grazia; Radford, Alan D; Thiry, Etienne; Truyen, Uwe; Möstl, Karin

    2015-07-01

    Regardless of whether a pathogen is viral, bacterial, parasitic, fungal or an emerging unknown, the mainstay of infectious disease control is hygiene, and the cornerstone of good hygiene is effective disinfection. Certain pathogens present a challenge to kill effectively: parvovirus, protozoal oocysts, mycobacteria, bacterial spores and prions resist most disinfectants but can be eliminated through heat, especially steam, which will kill protozoal oocysts. Heat is the safest and most effective disinfectant, but cannot be universally applied. Temperatures in washing machines and dishwashers should be at least 60 °C to eliminate pathogenic spores and resistant viruses. Enveloped viruses are susceptible to most disinfectants; of the non-enveloped viruses, parvovirus is recognised as being the most difficult to eradicate. Sodium hypochlorite is recommended for many applications: cleaning of floors, laundry, food preparation surfaces and utensils. Skin scrubs and rubs containing alcohols are more effective than those containing chlorhexidine, and less subject to contamination. Deficiency of the enzyme UDP-glucuronosyl transferase renders the cat susceptible to the toxic effects of phenol-based disinfectants (including many essential oils), so these should be avoided in feline environments. Quaternary ammonium compounds (eg, benzalkonium chloride) are also probably best avoided. Veterinary disinfection approaches in the future may include use of ultraviolet radiation and, increasingly, silver. © Published by SAGE on behalf of ISFM and AAFP 2015.

  7. A review on wastewater disinfection

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2013-01-01

    Full Text Available Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent disinfection. Understanding the differences in inactivation mechanisms is critical to identify rate-limiting steps involved in the inactivation process as well as to develop more effective disinfection strategies. Disinfection byproducts discharged from wastewater treatment plants may impair aquatic ecosystems and downstream drinking-water quality. Numerous inorganic and organic micropollutants can undergo reactions with disinfectants. Therefore, to mitigate the adverse effects and also to enhance that efficiency, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. This review gives a summary of the traditional, innovative, and combined disinfection alternatives and also disinfection byproducts for effluent of municipal wastewater treatment plants.

  8. Reduction of date microbial load with ozone

    Science.gov (United States)

    Farajzadeh, Davood; Qorbanpoor, Ali; Rafati, Hasan; Isfeedvajani, Mohsen Saberi

    2013-01-01

    Background: Date is one of the foodstuffs that are produced in tropical areas and used worldwide. Conventionally, methyl bromide and phosphine are used for date disinfection. The toxic side effects of these usual disinfectants have led food scientists to consider safer agents such as ozone for disinfection, because food safety is a top priority. The present study was performed to investigate the possibility of replacing common conventional disinfectants with ozone for date disinfection and microbial load reduction. Materials and Methods: In this experimental study, date samples were ozonized for 3 and 5 hours with 5 and 10 g/h concentrations and packed. Ozonized samples were divided into two groups and kept in an incubator which was maintained at 25°C and 40°C for 9 months. During this period, every 3 month, microbial load (bacteria, mold, and yeast) were examined in ozonized and non-ozonized samples. Results: This study showed that ozonization with 5 g/h for 3 hours, 5 g/h for 5 hours, 10 g/h for 3 hours, and 10 g/h for 5 hours leads to about 25%, 25%, 53%, and 46% reduction in date mold and yeast load and about 6%, 9%, 76%, and 74.7% reduction in date bacterial load at baseline phase, respectively. Appropriate concentration and duration of ozonization for microbial load reduction were 10 g/h and 3 hours. Conclusion: Date ozonization is an appropriate method for microbial load reduction and leads to an increase in the shelf life of dates. PMID:24124432

  9. Isolation of a bacteria of the Bacillus genus as indicator in the disinfection of residual waters by means of the ionizing radiation (e{sup -} , {gamma}); Aislamiento de una bacteria del genero Bacillus como indicador en la desinfeccion de aguas residuales mediante la radiacion ionizante (e{sup -} , {gamma})

    Energy Technology Data Exchange (ETDEWEB)

    Mata J, M

    2003-07-01

    The pollutants of the water can be chemical, physical and biological. Among those biological we find to the microorganisms: bacterias, virus and protozoa. These cause important infections in many countries, mainly of Latin America. With the advance of the technology and the quick demographic growth, the biological pollution of the water has already become an important topic since it would damage the public health and it causes that their disinfection has greater attention. In the treatment of residual waters three basic treatments exist the one primary, secondary and tertiary; in this last we find the disinfection, which can be taken to end by chemical and physical methods. For this work of investigation it was used the ionizing radiation, because it is an innovative technology that it eliminates microorganisms in residual waters. The investigation consisted on treating, samples of residual water after the biological treatment of the plant RECICLAGUA with ionizing radiation (electrons and gammas), for the case of electrons it was used the dose of 0.5 kGy and for gamma the dose, of 5 kGy, later the survivor bacteria was isolated to these doses in both cases and they were carried out the tests of identification. In accordance with the obtained results can say that it is about a B. subtilis. The isolated B.subtilis was presented as a pollutant of the flora of the residual water, having a greater survival to the dose of 0.5 and 5 kGy with electrons and gammas, respectively that other present polluting microorganisms in the samples of residual water. For it fits signalize that this microorganism shows characteristics as it easy isolation and identification, the presence with pathogen microorganisms and a greater survival when being irradiated, therefore it can use as indicator in the disinfection of residual waters through ionizing radiation (electrons and gammas). (Author)

  10. Sanitizers and Disinfectants Guide. Revised

    Science.gov (United States)

    Healthy Schools Network, Inc., 2012

    2012-01-01

    Sanitizers and disinfectants can play an important role in protecting public health. They are designed to kill "pests," including infectious germs and other microorganisms such as bacteria, viruses, and fungi. Unfortunately, sanitizers and disinfectants also contain chemicals that are "pesticides." Exposure to persistent toxic…

  11. Disinfection of stockyards.

    Science.gov (United States)

    Fotheringham, V J

    1995-06-01

    Stockyards are premises where livestock from different sources are brought together for a period of time, before returning to their place of origin, or moving on to new premises or to the abattoir. Such premises pose particular problems for disease control, as they are potential sources for the dissemination of disease agents over wide geographical areas. The author describes a thorough programme of cleaning and disinfection for use during the routine operation of a stockyard. A different programme is described for use in the event of an outbreak of an Office International des Epizooties List A disease, taking into account the extra risks involved in such a disease outbreak.

  12. Solar water disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R. [Universal Recycled Water Systems, Orlando, FL (United States); Collier, R. [Enerscope, Inc., Merritt Island, FL (United States)

    1996-11-01

    Non-potable drinking water is a major problem for much of the world`s population. It has been estimated that from 15 to 20 million children under the age of 5 die from diarrheal conditions brought on by infected drinking water every year. This is equivalent to a fully-loaded DC-10 crashing every ten minutes of every day, 365 days a year. Heat is one of the most effective methods of disinfecting drinking water. Using conventional means of heating water (heating on an open-flamed stove) results in an extremely energy-intensive process. The main obstacle is that for areas of the world where potable water is a problem, fuel supplies are either too expensive, not available, or the source of devastating environmental problems (deforestation). The apparatus described is a solar-powered water disinfection device that can overcome most if not all of the barriers that presently limit technological solutions to drinking water problems. It uses a parabolic trough solar concentrator with a receiver tube that is also a counterflow heat exchanger. The system is totally self-contained utilizing a photovoltaic-powered water pump, and a standard automotive thermostat for water flow control. The system is designed for simplicity, reliability and the incorporation of technology readily accessible in most areas of the world. Experiments at the Florida Solar Energy Center have demonstrated up to 2,500 liters of safe drinking water per day with 28 square meters of solar concentrator.

  13. Solar disinfection of water for low income communities; Desinfeccao solar de agua para comunidades de baixa renda

    Energy Technology Data Exchange (ETDEWEB)

    Felix, Lorna Falcao

    2010-03-15

    The use of solar energy for water disinfection, and is accessible to disadvantaged communities because of its low cost, has the advantage of using disposable materials such as bottles of polyethylene terephthalate (PET). We present a study that used two methods of disinfection: the methodology proposed by the project Solar Water Disinfection (SODIS), which consisted of water disinfection by solar radiation and temperature and the methodology which the temperature of the water for disinfection. In both, we seek to eliminate microorganisms that cause serious diseases such as dysentery, typhoid, cholera, etc. Water samples were collected in the community of Bass, where the population has low income and the incidence of waterborne diseases is high. The experiments were divided into two stages. In step 1 we studied the feasibility of disinfection and in step 2 the feasibility of the pilot plant to obtain adequate levels of disinfection temperatures desired. The results showed the efficiency of the disinfection process, reaching an average of 80 to 100% death of microorganisms, but regrowth was observed in some samples. Finally on the good results of stage 1, is designed and built and tested in an experimental pilot plant, which has shown to be feasible to promote water disinfection through the use of solar energy. The water after treatment is in accordance with the limits established by Brazilian legislation for clean water, maintaining a positive performance for the disinfection and acceptable levels of bacterial regrowth. (author)

  14. Study of sequential disinfection for the inactivation of protozoa and indicator microorganisms in wastewater

    Directory of Open Access Journals (Sweden)

    Raphael Corrêa Medeiros

    2015-05-01

    Full Text Available Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine and ultraviolet radiation, and sequential disinfection (chlorine-UV radiation. The tests were conducted with anaerobic effluent in batch, in laboratory scale, with two dosages of chlorine (10 and 20 mg L-1 and UV (2.5 and 6.1 Wh m-3. In addition, to guarantee the presence of cysts in the tests, 104 cysts per liter of Giardia spp. were inoculated. The resistance order was as follows: E. coli = Total Coliforms < Clostridium perfringens < Giardia spp.. Furthermore, synergistic effects reached 0.06 to 1.42 log of inactivation in sequential disinfection for both the most resistant microorganisms.

  15. Disinfecting capabilities of oxychlorine compounds.

    OpenAIRE

    Noss, C I; Olivieri, V P

    1985-01-01

    The bacterial virus f2 was inactivated by chlorine dioxide at acidic, neutral, and alkaline pH values. The rate of inactivation increased with increasing pH. Chlorine dioxide disproportionation products, chlorite and chlorate, were not active disinfectants. As chlorine dioxide solutions were degraded under alkaline conditions, they displayed reduced viricidal effectiveness, thereby confirming the chlorine dioxide free radical as the active disinfecting species.

  16. New disinfection and sterilization methods.

    OpenAIRE

    Rutala, W A; Weber, D.J.

    2001-01-01

    New disinfection methods include a persistent antimicrobial coating that can be applied to inanimate and animate objects (Surfacine), a high-level disinfectant with reduced exposure time (ortho-phthalaldehyde), and an antimicrobial agent that can be applied to animate and inanimate objects (superoxidized water). New sterilization methods include a chemical sterilization process for endoscopes that integrates cleaning (Endoclens), a rapid (4-hour) readout biological indicator for ethylene oxid...

  17. UV Disinfection System for Cabin Air

    Science.gov (United States)

    Lim, Soojung

    Ultraviolet (UV) radiation is commonly used for disinfection of water. As a result of advancements made in the last 10-15 years, the analysis and design of UV disinfection systems for water is well developed. UV disinfection is also used for disinfection of air; however, despite the fact the UV-air systems have a longer record of application than UV-water systems, the methods used to analyze and design UV-air disinfection systems remain quite empirical. It is well-established that the effectiveness of UV-air systems is strongly affected by the type of microorganisms, the irradiation level/type (lamp power and wavelength), duration of irradiation (exposure time), air movement pattern (mixing degree), and relative humidity. This paper will describe ongoing efforts to evaluate, design and test a UV-air system based on first principles. Specific issues to be addressed in this work will include laboratory measurements of relevant kinetics (i.e., UV dose-response behavior) and numerical simulations designed to represent fluid mechanics and the radiation intensity field. UV dose-response behavior of test microorganism was measured using a laboratory (bench-scale) system. Target microorganisms (e.g., bacterial spores) were first applied to membrane filters at sub-monolayer coverage. The filters were then transferred to an environmental chamber at fixed relative humidity (RH) and allowed to equilibrate with their surroundings. Microorganisms were then subjected to UV exposure under a collimated beam. The experiment was repeated at RH values ranging from 20% to 100%. UV dose-response behavior was observed to vary with RH. For example, at 100% RH, a UV dose of 20 mJ/cm2 accomplished 90% (1 log10 units) of the B. subtilis spore inactivation, whereas 99 % (2 log10 units) inactivation was accomplished at this same UV dose under 20% RH conditions. However, at higher doses, the result was opposite of that in low dose. Reactor behavior is simulated using an integrated application

  18. Dating Techniques

    Indian Academy of Sciences (India)

    Absolute dating technique (such as stylistic affiliation, association with datable deposits, amino acid study of protein in pigments, and direct radiocarbon dating of the organic fraction of pigments or desert varnish).

  19. Radiocarbon Dating

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A

    2007-12-20

    Radiocarbon dating can be used to determine the age of objects that contain components that were once alive. In the case of human remains, a radiocarbon date can distinguish between a crime scene and an archeological site. Documents, museum artifacts and art objects can be dated to determine if their age is correct for the historical context. A radiocarbon date does not confirm authenticity, but it can help identify a forgery.

  20. Dating Violence

    Science.gov (United States)

    Stader, David L.

    2011-01-01

    Dating violence is a form of student-on-student victimization and is a serious school safety issue. Research indicates that at a minimum, 10 percent of high school students are victims of dating violence in one form or another. Among female high school students that date, some data indicate that as many as 30 percent may be victims of dating…

  1. Disinfection of the Peritoneal Dialysis Bag Medication Port: Comparison of Disinfectant Agent and Disinfection Time.

    Science.gov (United States)

    Conti, Adriana; Katzap, Roberta Monteiro; Poli-de-Figueiredo, Carlos Eduardo; Pagnussatti, Vany; Figueiredo, Ana Elizabeth

    2017-07-13

    To compare different disinfection techniques for the peritoneal dialysis bag medication port (MP). An experimental study was conducted testing different cleaning agents (70% alcohol vs 2% chlorhexidine) and time periods (5, 10 and 60 seconds) for disinfection of the MP. Five microorganisms (S. aureus, E.coli, A. baumannii and C. parapsilosis, CNS) were prepared for use as contaminants of the MP. MP were incubated in Tryptic soy broth at 36 °C for 24 h, after which, they were seeded on a Biomérieux® blood agar plate and incubated for 24 h at 36 °C. 300 peritoneal dialysis bags were analyzed regarding the time expose to the disinfectant showed a statistically significant difference in the number of culture positive (7/100) p = 0.001; Gram positive (6/100) p = 0.006 for five seconds, one positive culture and turbid bag with ten seconds, while friction for 60 seconds showed all negative results. The comparison between disinfectant, alcohol or chlorhexidine, 150 bag in each group, showed that the ones disinfected with alcohol had 5 turbid bags, 8 positive cultures and 7 germs identified, while all bags disinfected with chlorhexidine were negative for all parameters, with a difference statistically significant (p = 0.004). Our results suggest that the MP should be scrubbed with 2% chlorhexidine for at least 5 seconds; if alcohol 70% is used the length of friction should not be inferior to 10 seconds. This article is protected by copyright. All rights reserved.

  2. Environmentally friendly disinfectant: Production, disinfectant action and efficiency

    Directory of Open Access Journals (Sweden)

    Čekerevac Milan I.

    2006-01-01

    Full Text Available Silver is a known disinfectant from ancient times, and it has been widely used for various purposes: for food and water disinfection, curing of wounds and as a universal antibiotic for a wide spectrum of diseases - until the Second World War and the discovery of penicillin. Until recently, it was assumed that silver, being a heavy metal, was toxic for humans and living beings. However, the newest research provides facts that the usage of silver, even for drinking water disinfection, is benign if it is added in small concentrations (in parts per billion. It has been shown in the newer scientific and technical literature that silver in colloidal form is a powerful (secondary disinfectant for drinking water, that it can be effectively used for the disinfection of water containers including swimming pools, installations in food industry, medicine, etc. Particularly, it has been shown that colloidal silver combined with hydrogen peroxide shows synergism having strong bactericidal and antiviral effects. The combination can be successfully used as a disinfectant in agriculture, food production and medicine. The original electrochemical process of production, the mechanism of physical-chemical reactions in that process and the mechanism of the antiseptic affect of the environmentally friendly disinfectant, based on the synergism of colloidal silver and hydrogen peroxide and the activity of electrochemically activated water, is shown. The starting solution was anolyte, obtained in electrochemical activation by water electrolysis of a highly diluted solution of K-tartarate in demineralized water (5.5-1CT4 M. The problem of electrolysis of very dilute aqueous solutions in membrane cells was particularly treated. It was shown that the efficiency of the electrolysis depends on the competition between the two processes: the rates of the processes of hydrogen and oxygen generation at the electrodes and the process of diffusion of hydrogen and hydroxyl ions

  3. date extended

    Indian Academy of Sciences (India)

    C A L AN DER OF EVENTS. Date of issue of bid document : 2016 September 21. Extended Due date and Time for Receipt of Tender : Up to 2016 October 17, Time 13:00 Hrs. Date and Time of opening of bid : 2016 October 17, Time 15:00 Hrs. Cost of Bid Document : Rs. 100/- only (Non-refundable). Earnest Money Deposit ...

  4. A comparative study of disinfection efficiency and regrowth control of microorganism in secondary wastewater effluent using UV, ozone, and ionizing irradiation process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, O-Mi [Quarantine Technology Center, Animal and Plant Quarantine Agency Plant, 175 Anyangro, Manan-Gu, Anyang-Si, Gyeonggi-Do 480-757 (Korea, Republic of); Kim, Hyun Young; Park, Wooshin; Kim, Tae-Hun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup, Jeonbuk 580-185 (Korea, Republic of); Yu, Seungho, E-mail: seunghoyu68@gmail.com [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup, Jeonbuk 580-185 (Korea, Republic of)

    2015-09-15

    Highlights: • The ionizing radiation was applied to inactivate microorganisms and the critical dose to prevent the regrowth was determined. • The seasonal variation of disinfection efficiency observed in on-site UV treatment system was influenced by suspended solid, temperature, and precipitation, whereas, stable values were observed in ionizing radiation. • The electrical power consumption for disinfection using UV and ozone requires higher energy than ionizing radiation. - Abstract: Ionizing radiation technology was suggested as an alternative method to disinfection processes, such as chlorine, UV, and ozone. Although many studies have demonstrated the effectiveness of irradiation technology for microbial disinfection, there has been a lack of information on comparison studies of disinfection techniques and a regrowth of each treatment. In the present study, an ionizing radiation was investigated to inactivate microorganisms and to determine the critical dose to prevent the regrowth. As a result, it was observed that the disinfection efficiency using ionizing radiation was not affected by the seasonal changes of wastewater characteristics, such as temperature and turbidity. In terms of bacterial regrowth after disinfection, the ionizing radiation showed a significant resistance of regrowth, whereas, on-site UV treatment is influenced by the suspended solid, temperature, or precipitation. The electric power consumption was also compared for the economic feasibility of each technique at a given value of disinfection efficiency of 90% (1-log), showing 0.12, 36.80, and 96.53 Wh/(L/day) for ionizing radiation, ozone, and UV, respectively. The ionizing radiation requires two or three orders of magnitude lower power consumption than UV and ozone. Consequently, ionizing radiation can be applied as an effective and economical alternative technique to other conventional disinfection processes.

  5. Cross-Resistance of UV- or Chlorine Dioxide-Resistant Echovirus 11 to Other Disinfectants

    Directory of Open Access Journals (Sweden)

    Qingxia Zhong

    2017-10-01

    Full Text Available The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat, and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.

  6. Cross-Resistance of UV- or Chlorine Dioxide-Resistant Echovirus 11 to Other Disinfectants.

    Science.gov (United States)

    Zhong, Qingxia; Carratalà, Anna; Ossola, Rachele; Bachmann, Virginie; Kohn, Tamar

    2017-01-01

    The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2)- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat), and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.

  7. New disinfection and sterilization methods.

    Science.gov (United States)

    Rutala, W A; Weber, D J

    2001-01-01

    New disinfection methods include a persistent antimicrobial coating that can be applied to inanimate and animate objects (Surfacine), a high-level disinfectant with reduced exposure time (ortho-phthalaldehyde), and an antimicrobial agent that can be applied to animate and inanimate objects (superoxidized water). New sterilization methods include a chemical sterilization process for endoscopes that integrates cleaning (Endoclens), a rapid (4-hour) readout biological indicator for ethylene oxide sterilization (Attest), and a hydrogen peroxide plasma sterilizer that has a shorter cycle time and improved efficacy (Sterrad 50).

  8. Roof-harvested rainwater for potable purposes: application of solar collector disinfection (SOCO-DIS).

    Science.gov (United States)

    Amin, M T; Han, M Y

    2009-12-01

    The efficiency of solar disinfection (SODIS), recommended by the World Health Organization, has been determined for rainwater disinfection, and potential benefits and limitations discussed. The limitations of SODIS have now been overcome by the use of solar collector disinfection (SOCO-DIS), for potential use of rainwater as a small-scale potable water supply, especially in developing countries. Rainwater samples collected from the underground storage tanks of a rooftop rainwater harvesting (RWH) system were exposed to different conditions of sunlight radiation in 2-L polyethylene terephthalate bottles in a solar collector with rectangular base and reflective open wings. Total and fecal coliforms were used, together with Escherichia coli and heterotrophic plate counts, as basic microbial and indicator organisms of water quality for disinfection efficiency evaluation. In the SOCO-DIS system, disinfection improved by 20-30% compared with the SODIS system, and rainwater was fully disinfected even under moderate weather conditions, due to the effects of concentrated sunlight radiation and the synergistic effects of thermal and optical inactivation. The SOCO-DIS system was optimized based on the collector configuration and the reflective base: an inclined position led to an increased disinfection efficiency of 10-15%. Microbial inactivation increased by 10-20% simply by reducing the initial pH value of the rainwater to 5. High turbidities also affected the SOCO-DIS system; the disinfection efficiency decreased by 10-15%, which indicated that rainwater needed to be filtered before treatment. The problem of microbial regrowth was significantly reduced in the SOCO-DIS system compared with the SODIS system because of residual sunlight effects. Only total coliform regrowth was detected at higher turbidities. The SOCO-DIS system was ineffective only under poor weather conditions, when longer exposure times or other practical means of reducing the pH were required for the

  9. Online dating

    OpenAIRE

    Pilecká, Jarmila

    2014-01-01

    The usage of online dating sides has increased in last few decades. This kind of meeting potential new partner is specific in many ways. Especially in communication, ways of selection and initiation of the relationship online. The reduction of information is another phenomenon in this kind of interaction as a result of creating impression. This contains lying and deception in self-presentation on online dating sides as well. Analysis of data suggests, that men tell lies more than women. They ...

  10. Stormwater disinfection using Electrochemical oxidation

    OpenAIRE

    WENJUN FENG

    2017-01-01

    This thesis demonstrates that electrochemical oxidation can be a promising stormwater disinfection technique to achieve regulatory water re-uses targets. It discusses the implications for the practical implementation of the technology and identifies areas for future research in regards to optimisation of the technology

  11. Designing plasmas for chronic wound disinfection

    Science.gov (United States)

    Nosenko, T.; Shimizu, T.; Morfill, G. E.

    2009-11-01

    Irradiation with low-temperature atmospheric-pressure plasma provides a promising method for chronic wound disinfection. To be efficient for this purpose, plasma should meet the following criteria: it should significantly reduce bacterial density in the wounded area, cause a long-term post-irradiation inhibition of bacterial growth, yet without causing any negative effect on human cells. In order to design plasmas that would satisfy these requirements, we assessed the relative contribution of different components with respect to bactericidal properties due to irradiation with argon plasma. We demonstrate that plasma-generated UV radiation is the main short-term sterilizing factor of argon plasma. On the other hand, plasma-generated reactive nitrogen species (RNS) and reactive oxygen species (ROS) cause a long-term 'after-irradiation' inhibition of bacterial growth and, therefore, are important for preventing wound recolonization with bacteria between two treatments. We also demonstrate that at certain concentrations plasma-generated RNS and ROS cause significant reduction of bacterial density, but have no adverse effect on human skin cells. Possible mechanisms of the different effects of plasma-generated reactive species on bacteria and human cells are discussed. The results of this study suggest that argon plasma for therapeutic purposes should be optimized in the direction of reducing the intensity of plasma-generated UV radiation and increasing the density of non-UV plasma products.

  12. Direct Dating

    Indian Academy of Sciences (India)

    For example, rock engravings and paintings are partially covered with lichens which are slow – growing, long – ranging and increase in diameter at a constant rate. The technique depends upon development of a specific lichen growth curve by measuring lichen thallus diameters on dated rock surfaces. This can then be ...

  13. Chemical disinfection of combined sewer overflows

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar

    for a preliminary risk assessment of disinfectants entering the aquatic ecosystem in the receiving water’s post-disinfection discharge. Performic acid (PFA) and peracetic acid (PAA) are used to disinfect CSO water, in order to reduce the number of indicator bacteria. Moreover, PFA and PAA do not form toxic by......-products when they react with the ammonia present in the CSO. Disinfectant dose and contact time in the present study were designed by disinfecting a laboratory-simulated CSO with different wastewater concentrations. Degradation kinetics of PFA and PAA in the simulated CSO as well as the disinfection efficiency...... were studied. PAA degradation in the simulated CSO was slower compared to the degradation of PFA, the latter of which, at a dose (1-8 mg/L) and with 10 minutes’ contact time, efficiently removed 4.2 logs of E. coli and 3 logs of Enterococcus spp from the simulated CSO. Furthermore, the ecotoxicity...

  14. Less skin irritation from alcohol-based disinfectant than from detergent used for hand disinfection

    DEFF Research Database (Denmark)

    Pedersen, L K; Held, E; Johansen, J D

    2005-01-01

    BACKGROUND: The benefit of alcohol-based disinfectant used on normal skin has been debated. OBJECTIVES: The objective of the present study was to compare the effects of repeated exposure to an alcohol-based disinfectant, a detergent and an alcohol-based disinfectant/detergent alternately for 10 d...

  15. Decontamination formulations for disinfection and sterilization

    Science.gov (United States)

    Tucker, Mark D.; Engler, Daniel E.

    2007-09-18

    Aqueous decontamination formulations that neutralize biological pathogens for disinfection and sterilization applications. Examples of suitable applications include disinfection of food processing equipment, disinfection of areas containing livestock, mold remediation, sterilization of medical instruments and direct disinfection of food surfaces, such as beef carcasses. The formulations include at least one reactive compound, bleaching activator, inorganic base, and water. The formulations can be packaged as a two-part kit system, and can have a pH value in the range of 7-8.

  16. Wastewater disinfection by combination of ultrasound and ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Naddeo, V., E-mail: vnaddeo@unisa.it [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Landi, M.; Belgiorno, V. [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Napoli, R.M.A. [Department of Environmental Science, University of Napoli Parthenope, Via Amm. F. Acton, 38, 80133 Napoli (Italy)

    2009-09-15

    Reclamation and reuse of wastewater is one of the most effective ways to alleviate water resource scarcity. In many countries very stringent limit for chlorination by-products such as trihalomethanes has been set for wastewater reuse. Accordingly, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Recently ultrasound (US) was found to be effective as pre-treatment for wastewater disinfection by UV irradiation. The aim of this work is to investigate the wastewater advanced treatment by simultaneous combination of UV and US in terms of bacteria inactivation (Total coliform and Escherichia coli) at pilot-scale. The pilot plant was composed of two reactors: US-UV reactor and UV reactor. The influence of different reaction times, respective US and UV dose and synergistic effect was tested and discussed for two different kinds of municipal wastewater. An important enhancement of UV disinfection ability has been observed in presence of US, especially with wastewater characterized by low transmittance. In particular the inactivation was greater for T. coliform than for E. coli. Furthermore, the results obtained showed also that the fouling formation on the lamps was slower in US-UV reactor than in UV reactor both with and without solar radiation.

  17. A study on the effect on surface detail reproduction of alginate impressions disinfected with sodium hypochlorite and ultraviolet light - An In Vitro study.

    Science.gov (United States)

    Shambhu, H S; Gujjari, Anil Kumar

    2010-03-01

    To evaluate the surface detail reproduction of dental casts with impressions made using commercially available alginate impression materials after disinfecting with chemical disinfectant sodium hypochlorite and physical means of disinfection using ultraviolet radiation. A stainless steel die was used to make impression according to ADA/ANSI specification No. 18 having 25, 50 and 75 µm lines. Totally 70 impressions were made and divided in to 7 groups. The impressions in the first group were only rinsed with 250 ml of water. The 2nd, 3rd and 4th groups were disinfected by immersing in sodium hypochlorite for 1, 5 and 10 minutes, respectively. Fifth, 6th and 7th group samples were disinfected by placing them in ultraviolet chamber for 6, 12 and 18 minutes, respectively. All the impressions were poured immediately using type III gypsum. The casts were recovered and subjected for evaluation of the 75 µm lines using stereomicroscope. There was no statistically significant change in the surface detail reproduction when disinfected with sodium hypochlorite or ultraviolet radiation. Alginate impressions subjected to immersion disinfection using sodium hypochlorite for 1, 5 and 10 minutes and subjected to ultraviolet disinfection for 6, 12 and 18 minutes exhibited no statistically significant differences for surface detail reproduction compared to control groups.

  18. Anaerobic effluent disinfection using ozone: Byproducts formation

    NARCIS (Netherlands)

    Silva, G.H.R.; Daniel, L.A.; Bruning, H.; Rulkens, W.H.

    2010-01-01

    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15

  19. Ultraviolet (UV) Disinfection for Drinking Water Systems

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  20. Silver disinfection in water distribution systems

    Science.gov (United States)

    Silvestry Rodriguez, Nadia

    Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

  1. Cleaning and Disinfection of Bacillus cereus Biofilm.

    Science.gov (United States)

    Deal, Amanda; Klein, Dan; Lopolito, Paul; Schwarz, John Spencer

    2016-01-01

    Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility. Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to

  2. TL and EPR dating: some applications

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S. [Institute of Physics, University of Sao Paulo, Sao Paulo (Brazil)

    2006-07-01

    The intensity of thermoluminescence light emitted by a crystal is a function of radiation dose. The number of defects or of radicals in a crystal or organic substances is also a function of radiation dose. Since such defects or radicals present EPR signals, the EPR intensity is also a function of radiation dose. These facts are basis for radiation dosimetry and can be applied in dating of archaeological potteries or other materials, as well as in dating geological substances such as sediments, caves speleothemes, animal teeth and bones. Recent investigation on sensitized quartz based dosimeters and dating calcite covering ancient wall painting to find early settlers in Brazil will be presented. (Author)

  3. Point-of-use water disinfection using ultraviolet and visible light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Lui, Gough Yumu, E-mail: gough@student.unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Roser, David, E-mail: djroser@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Corkish, Richard, E-mail: r.corkish@unsw.edu.au [School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Ashbolt, Nicholas J., E-mail: ashbolt@ualberta.ca [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); School of Public Health, South Academic Building, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); Stuetz, Richard, E-mail: r.stuetz@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)

    2016-05-15

    Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270–740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6 h. Five log{sub 10} and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log{sub 10}s E. coli and E. faecalis over the 6 h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for > 3-log{sub 10} reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5–2.5 fold at 365–455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work. - Highlights: • Disinfection of E. coli and E. faecalis achieved with 270 and 365–455 nm LEDs • No significant disinfection was found with 310 and > 455 nm LEDs

  4. Inflation of Molecular Clock Rates and Dates: Molecular Phylogenetics, Biogeography, and Diversification of a Global Cicada Radiation from Australasia (Hemiptera: Cicadidae: Cicadettini).

    Science.gov (United States)

    Marshall, David C; Hill, Kathy B R; Moulds, Max; Vanderpool, Dan; Cooley, John R; Mohagan, Alma B; Simon, Chris

    2016-01-01

    Dated phylogenetic trees are important for studying mechanisms of diversification, and molecular clocks are important tools for studies of organisms lacking good fossil records. However, studies have begun to identify problems in molecular clock dates caused by uncertainty of the modeled molecular substitution process. Here we explore Bayesian relaxed-clock molecular dating while studying the biogeography of ca. 200 species from the global cicada tribe Cicadettini. Because the available fossils are few and uninformative, we calibrate our trees in part with a cytochrome oxidase I (COI) clock prior encompassing a range of literature estimates for arthropods. We show that tribe-level analyses calibrated solely with the COI clock recover extremely old dates that conflict with published estimates for two well-studied New Zealand subclades within Cicadettini. Additional subclade analyses suggest that COI relaxed-clock rates and maximum-likelihood branch lengths become inflated relative to EF-1[Formula: see text] intron and exon rates and branch lengths as clade age increases. We present corrected estimates derived from: (i) an extrapolated EF-1[Formula: see text] exon clock derived from COI-calibrated analysis within the largest New Zealand subclade; (ii) post hoc scaling of the tribe-level chronogram using results from subclade analyses; and (iii) exploitation of a geological calibration point associated with New Caledonia. We caution that considerable uncertainty is generated due to dependence of substitution estimates on both the taxon sample and the choice of model, including gamma category number and the choice of empirical versus estimated base frequencies. Our results suggest that diversification of the tribe Cicadettini commenced in the early- to mid-Cenozoic and continued with the development of open, arid habitats in Australia and worldwide. We find that Cicadettini is a rare example of a global terrestrial animal group with an Australasian origin, with all non

  5. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Science.gov (United States)

    2010-07-01

    ... Disinfection-Systems Serving 10,000 or More People § 141.172 Disinfection profiling and benchmarking. (a... profile of its disinfection practice for a period of up to three years. (2) The system must monitor daily... decides to make a significant change to its disinfection practice must consult with the State prior to...

  6. Chemical U-Th-Pb dating of monazite by 3D-Micro x-ray fluorescence analysis with synchrotron radiation

    DEFF Research Database (Denmark)

    Schmitz, Susanne; Möller, Andreas; Wilke, Max

    2009-01-01

    A confocal set-up for three-dimensional (3D) micro X-ray fluorescence (micro-XRF) was used at the mySpot beamline at BESSY II, which allows compositional depth profiling for various applications. We present results obtained with a confocal 3D micro-XRF set-up for chemical age dating using the U, Th...... and Pb concentrations of monazite within rock thin sections. The probing volume was determined to be approximately 21 × 21 × 24 µm3 for W-La using an excitation energy of 19 keV. The relative detection limits particularly for Pb are below 10 ppm (for counting times of 1000 s). Therefore, this 3D micro-XRF...... of ages, varying from 20 Ma to 1.82 Ga. Reference materials (GM3, F6, 3345) can be reproduced within error. The spread in the ages of all points determined by 3D micro-XRF is within 8 % of the isotopic reference value. The average 3D micro-XRF dates reproduce the reference ages with discrepancies between...

  7. Solar water disinfection (SODIS): A review from bench-top to roof-top

    Energy Technology Data Exchange (ETDEWEB)

    McGuigan, Kevin G., E-mail: kmcguigan@rcsi.ie [Royal College of Surgeons in Ireland, Dublin 2 (Ireland); Conroy, Ronan M. [Royal College of Surgeons in Ireland, Dublin 2 (Ireland); Mosler, Hans-Joachim [EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133: CH-8600 Duebendorf (Switzerland); Preez, Martella du; Ubomba-Jaswa, Eunice [CSIR, Natural Resources and the Environment, Pretoria, Gauteng (South Africa); Fernandez-Ibanez, Pilar [Plataforma Solar de Almeria - CIEMAT, P.O. Box 22, 07200 Tabernas, Almeria (Spain)

    2012-10-15

    Graphical abstract: . Water being treated by solar disinfection outside a primary school classroom in Southern Uganda. Students fill their bottles at home and expose them to the sun while they are at school. Highlights: Black-Right-Pointing-Pointer A thorough review of current state of play of solar water disinfection. Black-Right-Pointing-Pointer An examination of both laboratory and field studies. Black-Right-Pointing-Pointer Description of the economic and behaviour change aspects of this technology. - Abstract: Solar water disinfection (SODIS) has been known for more than 30 years. The technique consists of placing water into transparent plastic or glass containers (normally 2 L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to 48 h depending on the intensity of sunlight and sensitivity of the pathogens. Its germicidal effect is based on the combined effect of thermal heating of solar light and UV radiation. It has been repeatedly shown to be effective for eliminating microbial pathogens and reduce diarrhoeal morbidity including cholera. Since 1980 much research has been carried out to investigate the mechanisms of solar radiation induced cell death in water and possible enhancement technologies to make it faster and safer. Since SODIS is simple to use and inexpensive, the method has spread throughout the developing world and is in daily use in more than 50 countries in Asia, Latin America, and Africa. More than 5 million people disinfect their drinking water with the solar disinfection (SODIS) technique. This review attempts to revise all relevant knowledge about solar disinfection from microbiological issues, laboratory research, solar testing, up to and including real application studies, limitations, factors influencing adoption of the technique and health impact.

  8. Disinfection of human musculoskeletal allografts in tissue banking: a systematic review.

    Science.gov (United States)

    Mohr, J; Germain, M; Winters, M; Fraser, S; Duong, A; Garibaldi, A; Simunovic, N; Alsop, D; Dao, D; Bessemer, R; Ayeni, O R

    2016-12-01

    Musculoskeletal allografts are typically disinfected using antibiotics, irradiation or chemical methods but protocols vary significantly between tissue banks. It is likely that different disinfection protocols will not have the same level of microorganism kill; they may also have varying effects on the structural integrity of the tissue, which could lead to significant differences in terms of clinical outcome in recipients. Ideally, a disinfection protocol should achieve the greatest bioburden reduction with the lowest possible impact on tissue integrity. A systematic review of three databases found 68 laboratory and clinical studies that analyzed the microbial bioburden or contamination rates of musculoskeletal allografts. The use of peracetic acid-ethanol or ionizing radiation was found to be most effective for disinfection of tissues. The use of irradiation is the most frequently published method for the terminal sterilization of musculoskeletal allografts; it is widely used and its efficacy is well documented in the literature. However, effective disinfection results were still observed using the BioCleanse™ Tissue Sterilization process, pulsatile lavage with antibiotics, ethylene oxide, and chlorhexidine. The variety of effective methods to reduce contamination rate or bioburden, in conjunction with limited high quality evidence provides little support for the recommendation of a single bioburden reduction method.

  9. Vortex Stabilized Plasma for Rapid Water Disinfection & Pharmaceutical Degradation

    Science.gov (United States)

    Hershcovitch, Ady

    2016-10-01

    Good quality drinking water is dwindling for large segments of the world population. Aggravating the problem is proliferation of antibiotics in the water supply, which give rise to drug resistant pathogens. One option for water supply increase is recycling waste and polluted water by inexpensive, environmentally friendly methods. Presently disinfection uses chemicals and UV radiation. Chemicals are limited by residual toxicity, while UV consumes much electricity. Current methods can remove only certain classes of drugs due to their large variety of physical and chemical properties. Plasmas in water are very attractive for degrading all pharmaceuticals and deactivating pathogens: intense arc current can physically break up any molecular bonds. UV radiation, ozone, etc. generation inside the water volume disinfects. Present utilized plasmas: glow, pulsed arcs are not power efficient; vortex stabilized plasmas are power efficient that can advance water treatment state-of-the-art by orders of magnitude. Proposed techniquefeatures novel components facilitating large diameter vortex stabilized in-water arcs with optimized plasma parameters for maximal UV-C emission; and harvests hydrogen centered by the vortex.

  10. In-depth disinfection of acrylic resins.

    Science.gov (United States)

    Chau, V B; Saunders, T R; Pimsler, M; Elfring, D R

    1995-09-01

    This study demonstrated that bacteria penetrate three kinds of dental acrylic resin after a short time period. Samples of acrylic resin were contaminated with a variety of bacteria and were then placed in three different disinfecting solutions as directed by the manufacturers. After the specific dilution and immersion time, cultures were made from the resin samples. The only effective disinfectant was a 0.525% solution of sodium hypochlorite at a 10-minute immersion. It disinfected not only the surfaces but also the bacteria that penetrated the surfaces to a depth of 3 mm.

  11. [Disinfection efficiency for outlet water from biological activated carbon process by different disinfecting modes].

    Science.gov (United States)

    Zhi, Xing-hua; Bai, Xiao-hui; Meng, Ming-qun

    2011-05-01

    Lab-scale tests were designed to treat the leak of bacteria from BAC process. Water samples from outlet of BAC pool in Xujing Waterworks in Shanghai were disinfected by NaClO and NH2Cl disinfectant to compare the disinfection efficiency. Heterotrophic bacteria in disinfected water were cultivated and counted and halo hydrocarbons were detected by GC. To keep the disinfecting efficacy [lg(N0/N)] over 2 under the water temperature of 30 degrees C, NaClO should have an initial concentration more than 1.84 mg/L total chlorine and contact with bacteria for about 30 minutes. As to NH2Cl disinfection, the initial concentration should be more than 2.20 mg/L total chlorine and contacting time should be prolonged to about 90 minutes. The production of CHCl3 ranged from 4.97 to 7.10 microg/L and CCl4 ranged from 0.01 to 0.71 microg/L in NaClO disinfection tests with a initial disinfecting concentration in the range of 1.53-2.42 mg/L total chlorine values. In NH2Cl disinfecting tests, CHCl3 ranged from 4.43 to 5.55 microg/L and CCl4 ranged from 0.01 to 0.64 microg/L when initial disinfecting concentration limited in the range of 2.10-2.86 mg/L total chlorine values. All was below the state drinking water standard. The results showed that the disinfection process can be divided into fast step and slow step. NaCl0 has higher disinfecting efficiency on bacteria than NH2Cl, but neither can reach 100% effectivity. Meanwhile the risk of producing halo hydrocarbon over standard was proved to be negligible.

  12. Solar water disinfection (SODIS): a review from bench-top to roof-top.

    Science.gov (United States)

    McGuigan, Kevin G; Conroy, Ronán M; Mosler, Hans-Joachim; du Preez, Martella; Ubomba-Jaswa, Eunice; Fernandez-Ibañez, Pilar

    2012-10-15

    Solar water disinfection (SODIS) has been known for more than 30 years. The technique consists of placing water into transparent plastic or glass containers (normally 2L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to depending on the intensity of sunlight and sensitivity of the pathogens. Its germicidal effect is based on the combined effect of thermal heating of solar light and UV radiation. It has been repeatedly shown to be effective for eliminating microbial pathogens and reduce diarrhoeal morbidity including cholera. Since 1980 much research has been carried out to investigate the mechanisms of solar radiation induced cell death in water and possible enhancement technologies to make it faster and safer. Since SODIS is simple to use and inexpensive, the method has spread throughout the developing world and is in daily use in more than 50 countries in Asia, Latin America, and Africa. More than 5 million people disinfect their drinking water with the solar disinfection (SODIS) technique. This review attempts to revise all relevant knowledge about solar disinfection from microbiological issues, laboratory research, solar testing, up to and including real application studies, limitations, factors influencing adoption of the technique and health impact. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. [The use of UV rays for the disinfection of water. I. Microbiologic studies of drinking water].

    Science.gov (United States)

    Martiny, H; Wlodavezyk, K; Harms, G; Rüden, H

    1988-01-01

    As a physical disinfection method without chemicals required the ultraviolet irradiation was tested for disinfection of drinking water. The survival was measured as a function of exposure to radiation for S. enteritidis, E. cloacae, C. freundii, S. marcescens, E. coli, K. pneumoniae und S. faecium. The bacteria were grown in trypton soya broth until they were well into the exponential phase. Two different UV-disinfection units were tested. Both consist of cylindrical shaped chambers with one low-pressure mercury-discharge lamp with their longitudinal axis parallel to the chambers. With 10(6) cfu/ml the experiments were done with three different rates of flow of 7,2 m3/h, 4,0 m3/h and 2,0 m3/h. The minimum exposures to radiation necessary to cause a 99.999% reduction were 10-86 mWs/cm2 depending on the test bacterium and on the UV-disinfection unit. The minimum doses ranged for S. enteritidis up to 13 mWs/cm2, for E. coli up to 21 mWs/cm2, for K. pneumoniae up to 39 mWs/cm2, for S. faecium up to 42 mWs/cm2, for E. cloacae up to 43 mWs/cm2, for C. freundii up to 72 mWs/cm2, and for S. marcescens up to 86 mWs/cm2.

  14. Disinfection of denture base acrylic resin.

    Science.gov (United States)

    Lin, J J; Cameron, S M; Runyan, D A; Craft, D W

    1999-02-01

    During repair or adjustments of acrylic resin removable complete and partial dentures, particles of the acrylic resin from the interior of the prosthesis may expose dental personnel to microbial health hazards if the prosthesis has not been thoroughly disinfected. This study investigates the efficacy of a commercially prepared microbial disinfectant (Alcide) on the external and internal surfaces of acrylic resins. Four groups of acrylic resin were incubated in an experimental model to simulate the oral environment over time. Specimens were treated in 2 groups, disinfected and not disinfected, and then further grouped by breaking and not breaking. Analysis was performed with microbial colony counts, SEM, and statistical analyses. Viable microorganisms still remain on the internal and external surfaces of treated resins. Chlorine dioxide reduces, but does not eliminate, viable microorganisms on these dental prostheses.

  15. Enhancing the Performance of Solar Water Disinfection with Potassium Persulfat: Laboratory Study with Enterococcus faecalis

    Directory of Open Access Journals (Sweden)

    Ghader Ghanizadeh

    2017-10-01

    Full Text Available Background & Aims of the Study: The safe drinking water providing is one of the most crucial objections in these centenaries. Bacterial water contamination and high rate of morbidity and mortality is crucial health threat. Efficiency of potassium persulfat (KPS associated solar disinfection as a novel water disinfection technology was evaluated in batch scale experiments, using Ent. faecalis (ATTCC 29212. Material and Methods: This research is a descriptive and experimental study which done on Tehran city, Iran. Ent. faecalis (ATTCC 29212 was provided in standard form from reference laboratory. Desired bacterial density in water was prepared by Mc Farland method. Water specimens were exhibited with solar radiations from 10 a.m to 16 p.m of Tehran local time. All experiments were conducted into 1.5 L volume of Damavand bottled water. Non-injured bacteria cells were detected by plating onto Bile Esculin azide agar media. Turbid water samples were provided by spiking of sterile slurry. Contact time (1-6 h, turbidity (30-200 NTU, KPS concentration (0.1, 0.7, 1.5 and 2 mMol/l, Ent. faecalis density(1000 and 1500 cell/ml and UV intensity  were independent and disinfection efficiency was a dependent variable, respectively. Results: Intensity of UVA solar irradiation varied from 3770 to 6263.3 µW/Cm2, with the highest value was measured on 13.30 p.m. In single SODIS and 1 hour contact time, increasing of bacterial closeness from 1000 to 1500 cell/ml implied disinfection performance decreasing in which, the vital bacteria was 10 and 20 cell/ml, respectively; but beyond of this contact time, a complete disinfection was occurred. Disinfection of Ent. faecalis was achieved within 2 h with single solar irradiation but KPS associated solar disinfection with applied dosage of KPS provide completely disinfection in 1 h in which the process efficiency was not influenced by increasing of bacterial density and turbidity up to 200 NTU. Conclusion: Association of

  16. [Disinfectants for the skin of premature].

    Science.gov (United States)

    Cucurachi, G; Tuoto, M G

    2010-06-01

    Nosocomial infections are among the leading causes of mortality and morbidity in neonatal intensive care units. Prevention of healthcare-associated infections is based on strategies that aim to limit susceptibility to infections by enhancing host defences, interrupting trasmission of organisms by healthcare workers and by promoting the judicious use of antimicrobials. Strategies for the prevention of nosocomial infections include hand hygiene practices, prevention of central venous (cvc)-related bloodstream infections, judicious use of antimicrobials for therapy, enhancement of host defences, skin care and early enteral feeding with human milk. Major concerns about the use of alcoholic chlorhexidine are for the high risk of skin burns in extremely premature infants during the first days of life, when the skin is thin and not fully keratinesed. Aqueous chlorhexidine could be less irritant when used in very low birthweigth infants and thus could represent a good option. A recent prospective trial of adult patients showed similar effectiveness of alcoholic and aqueos solutions of chlorexidine. However, to date no study evaluated whether the aqueos formulation is less harmful and as effective as the alcoholic formulation in neonatal infants. The lack of evidence for neonatal patients prompts urgent need for large randomised controlled trials comparing effectiveness and safety of different skin disinfectants before CVC placement in neonates and particulary in very low birth-weight infants. Nosocomial infections are still of the most serious problems for the neonatal intensive care unit. Therefore every effort must be implemented to reduce the incidence of these infections, can not be considered a toll required hospitalization, as it may not be acceptable for a place of shelter and care as the hospital may itself be a source of disease.

  17. Evaluation of Alternative Methods for Wastewater Disinfection

    Science.gov (United States)

    1994-09-01

    viruses in water and wastewater (Trojan, undated:l). Used properly, ultraviolet light can effectively destroy bacteria, viruses, algae and other...highly effective in disinfecting wastewaters of an industrial nature and viable for medium to large plants, where purified oxygen is readily available or...Alternatives This appendix provides information and cost data obtained from vendors in the wastewater disinfection industry . This data is provided for

  18. Efficient Disinfection of Tap and Surface Water with Single High Power 285 nm LED and Square Quartz Tube

    Directory of Open Access Journals (Sweden)

    Martin Hessling

    2016-01-01

    Full Text Available A small water disinfection system based on the combination of a strong single 25 mW LED with a wavelength of 285 nm and a short quartz tube with an outer rectangular cross section is presented. For the disinfection tests clear tap water and slightly turbid and yellow pond water are contaminated with high concentrations of Escherichia coli bacteria. These water samples are exposed to the germicidal 285 nm LED radiation while they flow through the quartz tube. The portion of surviving germs is determined by membrane filtration for different water qualities and flow rates. For clear tap water the bacteria concentration can be reduced by at least three orders of magnitude up to flow rates of about 20 L/h. In pond water the maximum flow rate for such a reduction is less than 3 L/h. These high disinfection capabilities and the small size of this system, allow its integration in medical systems for point of use disinfection or even its application in the Third World for decentralized water disinfection powered by small solar cells, because this disinfection capacity should be sufficient for small groups or families.

  19. Distribution models and a dated phylogeny for Chilean Oxalis species reveal occupation of new habitats by different lineages, not rapid adaptive radiation.

    Science.gov (United States)

    Heibl, Christoph; Renner, Susanne S

    2012-10-01

    Among the World's most challenging environments for plant life is the Atacama Desert, an arid zone extending over 1300 km and from sea level to 2000/3000 m altitude along the southwestern Andean foothills. Plants there and in the adjacent Mediterranean zone exhibit striking adaptations, and we here address the question whether in a species-rich clade such adaptations arose in parallel, at different times, or simultaneously. Answering this type of question has been a major concern of evolutionary biology over the past few years, with a growing consensus that lineages tend to be conservative in their vegetative traits and niche requirements. Combined nuclear and chloroplast DNA sequences for 112 species of Oxalidales (4900 aligned nucleotides) were used for a fossil-calibrated phylogeny that includes 43 of the 54 species of Chilean Oxalis, and species distribution models (SDMs) incorporating precipitation, temperature, and fog, and the phylogeny were used to reconstruct ancestral habitat preferences, relying on likelihood and Bayesian techniques. Since uneven collecting can reduce the power of SDMs, we compared 3 strategies to correct for collecting effort. Unexpectedly, the Oxalis flora of Chile consists of 7 distant lineages that originated at different times prior to the last Andean uplift pulse; some had features preadapting them to seasonally arid or xeric conditions. Models that incorporated fog and a "collecting activity surface" performed best and identified the Mediterranean zone as a hotspot of Oxalis species as well as lineage diversity because it harbors a mix of ancient and young groups, including insufficiently arid-adapted species. There is no evidence of rapid adaptive radiation.

  20. EFFICACY OF NOVEL WATER DISINFECTION TECHNIQUES IN HORTICULTURAL NUTRIENT RECYCLING.

    Science.gov (United States)

    Heungens, K; Clierinck, M; Inghelbrecht, S; Vissers, M

    2015-01-01

    Hydroponic systems used for growing potted ornamentals in greenhouses are commonly ebb-and-flow irrigation systems. The drainage water is usually recycled to save water and nutrients. To avoid the spread of pathogens in these closed irrigation systems, disinfection of the recycled water is standard practice. Growers can use slow sand filtration or UV-radiation techniques, but these methods are often either not sulted for specific problems or they require an excessively large investment. The objective of this study was to test less expensive but effective alternative disinfection systems. The efficacy of five disinfection systems against fungi and oomycetes was determined: Aqua-Hort (based on Cu-ions), Reciclean (performic acid), D1-OX Forte (CIO2), ECA (electrochemically activated water = anodic oxidation: hypochlorite and free radicals) and Newtec (also anodic oxidation). These five systems and a no-sterilization control were integrated in small closed ebb-and-flow circuits with nutrient solution reservoirs of 400 L each. Activity against Fusarium was excellent with ECA, good with Newtec and DI-OX Forte, moderate with high doses of Reciclean (250 ppm H2O2 and poor with the Aqua-Hort. There was no Pythium in the ECA and Newtec systems, while still so in the Aqua-Hort system, even at high doses (up to 7 ppm Cu++). Although the Reciclean (up to 100 ppm H2O2) and Aqua-Hort systems did not perform well against the pathogens, they did very well against algae; especially Reciclean was also useful against duckweed in water and liverwort on soil substrates. Concentrations of total Cl were elevated in water, substrate and plants after treatments with ECA and Newtec; other accumulations were Cu (Aqua-Hort), Na and SO4 (DI-OX Forte). However, only on a limited number of plant species these accumulations produced phytotoxic effects.

  1. Optimization of fixed titanium dioxide film on PET bottles and visual indicator for water disinfection

    Science.gov (United States)

    Heredia-Munoz, Manuel Antonio

    Water is perhaps the most important resource that sustains human life. According to the World Health Organization (WHO), almost two billion people do not have access to the required water that is needed to satisfy their daily needs and one billion do not have access to clean sources of water for consumption, most of them living in isolated and poor areas around the globe. Poor quality water increases the risk of cholera, typhoid fever and dysentery, and other water-borne illness making this problem a real crisis that humankind is facing. Several water disinfection technologies have been proposed as solutions for this problem. Solar water disinfection using TiO2 coated PET bottles was the alternative that is studied in this work. This technology does not only inactivate bacteria but also disintegrates organic chemicals that can be present in water. The objectives of this work address the optimization of the TiO 2 coated PET bottles technologies. The improvement on the bottle coating process, using two coats of 10% W/V of TiO2 in a solution of vinegar and sodium bicarbonate to form the TiO2 film, the use of a different indigo carmine (1.25 X 10-1mg/pill) concentration in the pill indicator of contamination, the increase of the disinfection rate through shaking the bottles, degradation under intermittent UV radiation and the effect of bottle size on photocatalytic water disinfection were among the most important findings. A new mathematical model that describes better photocatalytic water disinfection in TiO2 coated bottles and simulates water disinfection under different working conditions was another important achievement. These results can now be used to design a strategy for disseminating this technology in areas where it is required and, in that way, generate the greatest positive impact on the people needing safe drinking water.

  2. Influence of solar water disinfection on immunity against cholera: a review

    CSIR Research Space (South Africa)

    Ssemakalu, CC

    2014-09-01

    Full Text Available on the spread of waterborne diseases 115 The consumption of SODIS water in sub-Saharan African and various East Asian countries 116 has reduced the percentage of individuals acquiring water borne diseases such as dysentery 117 typhoid and cholera (Conroy, et... review, the possible influence that solar water disinfection may have on the immunity 35 against cholera is discussed. 36 Keywords: Cholera, SODIS, Solar Ultraviolet Radiation, Vaccine, V. cholerae, Waterborne 37 disease 38 39 40 3...

  3. Disinfection of laryngoscopes: A survey of practice

    Directory of Open Access Journals (Sweden)

    Vaishali Prabhakar Chaskar

    2017-01-01

    Full Text Available Background and Aims: The laryngoscope is a common piece of equipment used by anaesthesiologists. It has been identified as a potential source of cross infection. Although guidelines exist regarding appropriate disinfection practices, recent reviews suggest ineffectiveness of current methods of disinfection and poor compliance with the established protocols. We conducted a questionnaire-based survey to study the current disinfection practices being followed by a cross section of anaesthesiologists. Methods: A simple questionnaire containing 13 questions was distributed amongst anaesthesiologists in an anaesthesia conference. Data were analysed with percentage analysis. Results: Out of 250 delegates who attended the conference, 150 submitted the completed questionnaires. Residents constituted 41% and 46% were consultants. Eighteen (12% used only tap water for cleaning and 132 (88% used a chemical agent after rinsing with water. Out of 132, 76 (51% used detergent/soap solution, 29 (19% would wash and then soak in disinfectant or germicidal agents (glutaraldehyde, povidone iodine and chlorhexidine and 18 (12% would wipe the blade with an alcohol swab. With respect to disinfection of laryngoscope handles, 70% respondents said they used an alcohol swab, 18% did not use any method, 9% were not aware of the method being used, while 3% did not respond. Conclusion: Our results indicate wide variation in methods of decontamination of laryngoscopes. Awareness regarding laryngoscope as a potential source of infection was high. We need to standardise and implement guidelines on a national level and make available resources which will help to improve patient safety.

  4. Chemical disinfection of combined sewer overflows

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar

    of the residual disinfectants PFA, PAA and chlorine dioxide (ClO2), and their degradation products hydrogen peroxide and chlorite, in relation to organisms in the aquatic ecosystem was studied. With the help of ecotoxicity data, a preliminary environmental risk assessment of PFA, PAA and ClO2 for CSO disinfection...... of PFA, PAA and ClO2, a minimum dilution factor (590 times for PFA, 138 times for PAA and 700 times for ClO2) is needed for discharge into the surface water, to avoid the risk of toxic effect in the aquatic environment, albeit the rapid degradation of PFA and ClO2 in water will not have an acute toxic...... for a preliminary risk assessment of disinfectants entering the aquatic ecosystem in the receiving water’s post-disinfection discharge. Performic acid (PFA) and peracetic acid (PAA) are used to disinfect CSO water, in order to reduce the number of indicator bacteria. Moreover, PFA and PAA do not form toxic by...

  5. Disinfection for small water supplies: a technical guide

    CSIR Research Space (South Africa)

    Solsona, F

    1990-01-01

    Full Text Available This guide will present some disinfection systems, which will be useful in supporting disinfection programmes. The description of the different systems will provide a guideline for the selection of equipment base on balancing the simplicity...

  6. Chemical aspects of peracetic acid based wastewater disinfection

    National Research Council Canada - National Science Library

    Luukkonen, T; Teeriniemi, J; Prokkola, H; Rämö, J; Lassi, U

    2014-01-01

    Peracetic acid (PAA) has been studied for wastewater disinfection applications for some 30 years and has been shown to be an effective disinfectant against many indicator microbes, including bacteria, viruses, and protozoa...

  7. Performance of on-site Medical waste disinfection equipment in hospitals of Tabriz, Iran

    Directory of Open Access Journals (Sweden)

    Hassan Taghipour

    2016-10-01

    Full Text Available Background: The number of studies available on the performance of on-site medical waste treatment facilities is rare, to date. The aim of this study was to evaluate the performance of onsite medical waste treatment equipment in hospitals of Tabriz, Iran. Methods: A various range of the on-site medical waste disinfection equipment (autoclave, chemical disinfection, hydroclave, and dry thermal treatment was considered to select 10 out of 22 hospitals in Tabriz to be included in the survey. The apparatus were monitored mechanically, chemically, and biologically for a six months period in all of the selected hospitals. Results: The results of the chemical monitoring (Bowie-Dick tests indicated that 38.9% of the inspected autoclaves had operational problems in pre-vacuum, air leaks, inadequate steam penetration into the waste, and/or vacuum pump. The biological indicators revealed that about 55.55% of the samples were positive. The most of applied devices were not suitable for treating anatomical, pharmaceutical, cytotoxic, and chemical waste. Conclusion: Although on-site medical waste treating facilities have been installed in all the hospitals, the most of infectious-hazardous medical waste generated in the hospitals were deposited into a municipal solid waste landfill, without enough disinfection. The responsible authorities should stringently inspect and evaluate the operation of on-site medical waste treating equipment. An advanced off-site central facility with multi-treatment and disinfection equipment and enough capacity is recommended as an alternative.

  8. Activity and action screening of selected disinfectants

    Directory of Open Access Journals (Sweden)

    Kateřina Balharová

    2006-01-01

    Full Text Available This research work is aimed to monitoring of selected disinfectants´activity in operational conditions. Hereby there have been monitored two acidic disinfectants Despon K and Mikasan D, which have had-by their producer-stated different recommended concentration. These solutions were monitored in viewpoint of their activity at different temperature, time of circulation, pH and water hardness. In this work there were measured pH of solutions in unloaded medium to be compared with pH of solutions in loaded medium and this measuring was carried out regularly each week within a one month period. During this period there was also monitored total plate count (TPC, which was stated in the dairy, where samples were taken two-times monthly. It has been found, that the disinfectants Mikasan D and Mikal 94D are effective even by high water hardness.

  9. A Study on Effectiveness of Seven Disinfectants Against Possible ...

    African Journals Online (AJOL)

    Seven commonly used disinfectants abbreviated as A, B, C, D, E, F and G (A is, Glutaraldehyde and Coco – benzyl dimethyl ammonium chloride; B is, Didecyldimethyl ammonium bromide 50% w\\\\v; C is, Sodium hypochlorite; D is, pine disinfectant and antiseptic; E is, chloroxylenol; F is, phenol and that for disinfectant G is, ...

  10. Chemical aspects of peracetic acid based wastewater disinfection ...

    African Journals Online (AJOL)

    Peracetic acid (PAA) has been studied for wastewater disinfection applications for some 30 years and has been shown to be an effective disinfectant against many indicator microbes, including bacteria, viruses, and protozoa. One of the key advantages compared to, e.g., chlorine is the lack of harmful disinfection ...

  11. MODELING DISINFECTANT RESIDUALS IN DRINKING-WATER STORAGE TANKS

    Science.gov (United States)

    The factors leading to the loss of disinfectant residual in well-mixed drinking-water storage tanks are studied. Equations relating disinfectant residual to the disinfectant's reation rate, the tank volume, and the fill and drain rates are presented. An analytical solution for ...

  12. Effects of some antiseptics and disinfectants on Staphylococcus ...

    African Journals Online (AJOL)

    A total of 6 antiseptics and disinfectants at varying concentrations (20% - 100%) and contact time (10-60 minutes) were tested for the efficacy in the reduction of Staphylococcus aureus isolated from the hands of volunteers. Disinfectant 1 was the most effective disinfectant being bactericidal to S. aureus at 100% ...

  13. THE TOXICOLOGY OF COMPLEX MIXTURES OF DISINFECTION BY-PRODUCTS

    Science.gov (United States)

    Chemical disinfection of water is a major public health advance that has decreased dramatically water-borne disease. Chemical disinfectants react with naturally occurring organic and inorganic matter in water to produce a wide variety of disinfection byproducts (DBPs). DBP num...

  14. development of an automated batch-process solar water disinfection

    African Journals Online (AJOL)

    user

    (Joules) preset at the beginning of the experiment/disinfection process. Fig. 2: Schematic diagram of the automated batch- process solar water disinfection system. Fig. 3: Pictorial view of the automated batch-process solar water disinfection system. Figure 4: Circuitry of Arduino® microcontroller with the different sensors ...

  15. Comparison of Riboflavin and Toluidine Blue O as Photosensitizers for Photoactivated Disinfection on Endodontic and Periodontal Pathogens In Vitro.

    Directory of Open Access Journals (Sweden)

    Henrik Krarup Nielsen

    Full Text Available Photoactivated disinfection has a strong local antimicrobial effect. In the field of dentistry it is an emerging adjunct to mechanical debridement during endodontic and periodontal treatment. In the present study, we investigate the effect of photoactivated disinfection using riboflavin as a photosensitizer and blue LED light for activation, and compare it to photoactivated disinfection with the widely used combination of toluidine blue O and red light. Riboflavin is highly biocompatible and can be activated with LED lamps at hand in the dental office. To date, no reports are available on the antimicrobial effect of photoactivated disinfection using riboflavin/blue light on oral microorganisms. Planktonic cultures of eight organisms frequently isolated from periodontal and/or endodontic lesions (Aggregatibacter actinomycetemcomitans, Candida albicans, Enterococcus faecalis, Escherischia coli, Lactobacillus paracasei, Porphyromonas gingivalis, Prevotella intermedia and Propionibacterium acnes were subjected to photoactivated disinfection with riboflavin/blue light and toluidine blue O/red light, and survival rates were determined by CFU counts. Within the limited irradiation time of one minute, photoactivated disinfection with riboflavin/blue light only resulted in minor reductions in CFU counts, whereas full kills were achieved for all organisms when using toluidine blue O/red light. The black pigmented anaerobes P. gingivalis and P. intermedia were eradicated completely by riboflavin/blue light, but also by blue light treatment alone, suggesting that endogenous chromophores acted as photosensitizers in these bacteria. On the basis of our results, riboflavin cannot be recommended as a photosensitizer used for photoactivated disinfection of periodontal or endodontic infections.

  16. A UVC Device for Intra-luminal Disinfection of Catheters: In Vitro Tests on Soft Polymer Tubes Contaminated with Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Candida albicans

    DEFF Research Database (Denmark)

    Bak, Jimmy; Begovic, Tanja; Bjarnsholt, Thomas

    2011-01-01

    Bacterial colonization of central venous catheters (CVCs) causes severe complications in patients. As a result, developing methods to remove and prevent bacterial and fungal colonization of CVCs is imperative. Recently, we have demonstrated that disinfection by radiation of polymer tubes with UVC...... light is possible. In this paper we present dose-response results using a newly developed UVC disinfection device, which can be connected to a Luer catheter hub. The device was tested on soft polymer tubes contaminated with a pallet of microorganisms, including Candida albicans, Staphylococcus aureus......, Escherichia coli and Pseudomonas aeruginosa (ca 10(3) CFU mL(-1) ). The tubes were equipped with a modified catheter hub and interfaced to the disinfection device via a middle piece separating the disinfection device from the hub. The contamination lasted for 3 h prior to treatment to simulate an aseptic...

  17. Date Rape (For Teens)

    Science.gov (United States)

    ... Breath? Talking to Your Parents - or Other Adults Date Rape KidsHealth > For Teens > Date Rape Print A ... Yourself Getting Help Reporting a Rape What Is Date Rape? When people think of rape , they might ...

  18. On the Quality of ENSDF γ-Ray Intensity Data for γ-Ray Spectrometric Determination of Th and U and Their Decay Series Disequilibria, in the Assessment of the Radiation Dose Rate in Luminescence Dating of Sediments

    Science.gov (United States)

    De Corte, Frans; Vandenberghe, Dimitri; De Wispelaere, Antoine

    2005-05-01

    In luminescence dating of sediments, one of the most interesting tools for the determination of the annual radiation dose is Ge γ-ray spectrometry. Indeed, it yields information on both the content of the radioelements K, Th, and U, and on the occurrence — in geological times — of disequilibria in the Th and U decay series. In the present work, two methodological variants of the γ-spectrometric analysis were tested, which largely depend on the quality of the nuclear decay data involved: (1) a parametric calibration of the sediment measurements, and (2) the correction for the heavy spectral interference of the 226Ra 186.2 keV peak by 235U at 185.7 keV. The performance of these methods was examined via the analysis of three Certified Reference Materials, with the introduction of γ-ray intensity data originating from ENSDF. Relevant conclusions were drawn as to the accuracy of the data and their uncertainties quoted.

  19. Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks following Various Disinfection Procedures.

    Science.gov (United States)

    Marchesi, Isabella; Ferranti, Greta; Mansi, Antonella; Marcelloni, Anna M; Proietto, Anna R; Saini, Navneet; Borella, Paola; Bargellini, Annalisa

    2016-05-15

    Physical and chemical disinfection methods have been proposed with the aim of controlling Legionella water contamination. To date, the most effective procedures for reducing bacterial contamination have not yet been defined. The aim of this study was to assess the long-term effectiveness of various disinfection procedures in order to reduce both culturable and nonculturable (NC) legionellae in different hospital water networks treated with heat, chlorine dioxide, monochloramine, and hydrogen peroxide. The temperature levels and biocide concentrations that proved to give reliable results were analyzed. In order to study the possible effects on the water pipes, we verified the extent of corrosion on experimental coupons after applying each method for 6 months. The percentage of positive points was at its lowest after treatment with monochloramine, followed by chlorine dioxide, hydrogen peroxide, and hyperthermia. Different selections of Legionella spp. were observed, as networks treated with chlorine-based disinfectants were contaminated mainly by Legionella pneumophila serogroup 1, hyperthermia was associated with serogroups 2 to 14, and hydrogen peroxide treatment was associated mainly with non-pneumophila species. NC cells were detected only in heat-treated waters, and also when the temperature was approximately 60°C. The corrosion rates of the coupons were within a satisfactory limit for water networks, but the morphologies differed. We confirm here that chemical disinfection controls Legionella colonization more effectively than hyperthermia does. Monochloramine was the most effective treatment, while hydrogen peroxide may be a promising alternative to chlorine-based disinfectants due to its ability to select for other, less virulent or nonpathogenic species. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Wang, Juan [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhang, Yahe; Shi, Quan [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Zhang, Haifeng; Zhang, Yu [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Yang, Min, E-mail: yangmin@rcees.ac.cn [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2016-06-01

    Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AI{sub mod}), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water. - Highlights: • The formulas of 206 iodinated DBPs in chloraminated drinking water were proposed. • More than 68% of the I-DBPs might have aromatic or polycyclic aromatic structures. • Precursors with high aromaticity is preferential to form iodinated DBPs.

  1. To disinfect or not to disinfect in postharvest research on the fungal decay of apple?

    Science.gov (United States)

    Naets, Matthias; van Dael, Mattias; Vanstreels, Els; Daelemans, Dirk; Verboven, Pieter; Nicolaï, Bart; Keulemans, Wannes; Geeraerd, Annemie

    2018-02-02

    Postharvest losses of fruit and vegetables can reach up to 30%, the main cause being microbial decay. For apple fruit, mostly fungal pathogens, such as Penicillium expansum, Colletotrichum spp., Neofabraea spp. and Botrytis cinerea, are important. As such losses are unsustainable in many ways, it is necessary that research is conducted to prevent them. Generally, for plants and fruit grown under non-sterile field conditions, disinfection is carried out prior to the start of a phytopathological experiment. The motivation for this practice is the removal of background contamination so that it will not affect the experimental outcome and its interpretation. In literature, a plethora of disinfection methods exists, differing in disinfectant, strength and duration. The following two disinfectants are commonly used: sodium hypochlorite (NaOCl) and ethanol. This article presents a targeted investigation into the effects of these two disinfectants on apple fruit surface and physiology. The results clearly demonstrate that both were affected by both disinfectants. NaOCl caused oxidative damage to the apple's wax layer, causing it to crack. Ethanol affected a redistribution of the wax on the fruit surface and altered the wax composition and/or metabolism. Both NaOCl and ethanol treatment resulted in an increased respiration rate. Therefore, apple and possibly other fruit should not be disinfected in phytopathological studies. A negative control, as is typically used, is not solving this issue, as we clearly demonstrate that the living tissue shows metabolic effects following disinfection, and hence the study objects are changed, hampering a clear interpretation of the experimental outcomes. Moreover, fungal inoculation during experiments is typically taking place at rather large levels in wounded tissue (as infection success is the exception), outnumbering the variable levels of background population, if present. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. ESR dating of fault rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2002-03-15

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then trow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected from the Yangsan fault system. ESR dates from the this fault system range from 870 to 240 ka. Results of this research suggest that long-term cyclic fault activity continued into the pleistocene.

  3. Evaluation of the efficacy of chemical disinfectants for disinfection of heat-polymerised acrylic resin.

    Science.gov (United States)

    Orsi, Iara Augusta; Junior, Adalton Garcia; Villabona, Camilo Andrés; Fernandes, Flávio Henrique Carriço Nogueira; Ito, Isabel Yoko

    2011-12-01

    This study evaluated the efficacy of disinfectants on the internal aspect of heat-polymerised acrylic resin contaminated with microbial strains. Dentures absorb oral fluids and become contaminated by different microorganisms. Two hundred and fifty rectangular specimens were made of heat-polymerised acrylic resin, and then divided into five groups corresponding to the microbial strains (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, S. mutans and Enterococcus faecalis). After contamination, the specimens were immersed in 1 and 2% sodium hypochlorite and 2% glutaraldehyde for periods of 5, 10 and 15 min. The specimens were placed into tubes containing different broths and incubated at 35°C and then visually analysed. Turbidity in the medium indicated microbial growth. The Fisher's exact test was used in the analysis of the results. The strain E. faecalis was the most resistant to the disinfectant solutions, and among them, glutaraldehyde was more effective than 2 and 1% hypochlorite for disinfection for 5 min; in the 10-min period there were no differences between the disinfectants. In 15 min of immersion, 1% hypochlorite and glutaraldehyde were more effective than 2% hypochlorite. Disinfection for 10 min with 1% hypochlorite and glutaraldehyde is effective in disinfecting the internal aspect of heat-polymerised acrylic resin. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  4. ASSESSMENT OF THE EFFICIENCY OF DISINFECTION METHOD ...

    African Journals Online (AJOL)

    eobe

    The efficiencies of three disinfection methods namely boiling, water guard and pur purifier were assessed. ... Water is an indispensable resource for supporting life systems [2-. 4], while access to safe drinking water is a basic human right, which is essential for healthy life ...... developing country context: improving decisions.

  5. 40 CFR 141.72 - Disinfection.

    Science.gov (United States)

    2010-07-01

    ... treatment must be sufficient to ensure at least 99.9 percent (3-log) inactivation of Giardia lamblia cysts... for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the system....9 percent (3-log) inactivation and/or removal of Giardia lamblia cysts and at least 99.99 percent (4...

  6. Adaptive Mechanisms Underlying Microbial Resistance to Disinfectants

    Science.gov (United States)

    2016-02-01

    SPONSOR/MONITOR’S ACRONYM(S) EQBRD 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release...Used We used Lysol brand disinfectant, four-in-one all-purpose cleaner (U.S. Environmental Protection Agency registration number 777-89). This

  7. Microbial contamination and disinfection methods of pacifiers

    Science.gov (United States)

    NELSON, Paulo; LOUVAIN, Márcia Costa; MACARI, Soraia; LUCISANO, Marília Pacífico; da SILVA, Raquel Assed Bezerra; de QUEIROZ, Alexandra Mussolino; GATON-HERNÁNDEZ, Patrícia; da SILVA, Léa Assed Bezerra

    2015-01-01

    Objectives To evaluate the microbial contamination of pacifiers by Mutans Streptococci (MS) and the efficacy of different methods for their disinfection. Methods Twenty-eight children were assigned to a 4-stage changeover system with a 1-week interval. In each stage, children received a new pacifier and the parents were instructed to maintain their normal habits for 1 week. After this time, the pacifiers were subjected to the following 4 disinfection methods: spraying with 0.12% chlorhexidine solution, Brushtox® or sterile tap water, and immersion in boiling tap water for 15 minutes. Microbiological culture for MS and Scanning Electron Microscopy (SEM) were performed. The results were analyzed statistically by Friedman’s non-parametric test (a=0.05). Results The 0.12% chlorhexidine spray was statistically similar to the boiling water (p>0.05) and more effective than the Brushtox® spray and control (p<0.05). The analysis of SEM showed the formation of a cariogenic biofilm in all groups with positive culture. Conclusions Pacifiers become contaminated by MS after their use by children and should be disinfected routinely. Spraying with a 0.12% chlorhexidine solution and immersion in boiling water promoted better disinfection of the pacifiers compared with a commercial antiseptic toothbrush cleanser (Brushtox®). PMID:26537723

  8. Disinfection of water distribution systems for Legionella.

    Science.gov (United States)

    Lin, Y S; Stout, J E; Yu, V L; Vidic, R D

    1998-06-01

    Hospital-acquired legionnaires' disease arises from the presence of Legionella in hospital water systems. Legionella not only persists in hot water tanks but is also found in the biofilm throughout the entire water distribution system. Conditions within water systems that promote Legionella colonization include water temperature, configuration and age of the hot water tank, physicochemical constituents of the water, plumbing materials, and commensal microflora. Hospital-acquired legionnaires' disease has been prevented by instituting control measures directed at the water distribution system. These include superheat-and-flush, copper/silver ionization, ultraviolet light, instantaneous heating systems, and hyperchlorination. Each of the above disinfection methods has been proven to be effective in the short-term, but long-term efficacy has been difficult due to limitations associated with each method. The complexities of Legionella disinfection, including advantages and disadvantages of each method, are reviewed. A successful Legionella prevention program requires cooperation and communication among hospital administrative personnel, engineers, and infection control staff. Routine environmental surveillance cultures for Legionella are the critical component for successful long-term disinfection. Culture results document the efficacy of the disinfection method and alert the hospital staff to consider Legionella in hospitalized patients with pneumonia.

  9. Carbon nanoparticles for solar disinfection of water.

    Science.gov (United States)

    Maddigpu, Pratap Reddy; Sawant, Bhairavi; Wanjari, Snehal; Goel, M D; Vione, Davide; Dhodapkar, Rita S; Rayalu, S

    2018-02-05

    The present manuscript deals with the application of carbon nano particles (CNP) and chitosan (CHIT) in the form of CHIT-CNP composite for the disinfection of water. The CHIT-CNP composite was prepared by the solution casting method and characterized by TEM, XRD and elemental analysis. In the present investigation we study the disinfection efficiency towards E. coli bacteria of both CNP and CHIT-CNP, under sunlight (SODIS) in identical experimental conditions. Both CNP and CHIT-CNP enhanced disinfection as compared to SODIS alone, and comparable performance was achieved when the same dose of CNP in the two materials was applied. However, the CHIT-CNP composite is in the form of a fabric and it is easier to use and handle as compared to the CNP powder, especially in rural and resource-constrained areas. Moreover the SODIS-CHIT-CNP setup, when used in a compound parabolic collector (CPC) reactor showed high bactericidal efficiency compared to SODIS alone, which is promising for practical applications. The disinfection potential of the CNP powder was compared with that of the well-known material TiO 2 Degussa P25 (DP 25 ): DP 25 gave 6-log kill of bacteria in 180min, whereas CNP produced 6-log kill in 150min. Copyright © 2017. Published by Elsevier B.V.

  10. Virucidal efficacy of hydrogen peroxide vapour disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Terpstra, P.; Koopmans, M.; Duizer, E.

    2012-01-01

    Background: Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. Aim: To measure the

  11. STERILIZATION AND DISINFECTION IN A PRIVATE CLINIC

    African Journals Online (AJOL)

    STERILIZATION AND DISINFECTION. IN A PRIVATE CLINIC. M. A. Rahim. Aga Khan Hospital, Dar es Salaam,. Tanzania. Introduction. There is documented evidence that disease can be transmitted in dental practice (1). Hence careful measures of infection control in the daily routine in dental practice must be applied.

  12. symptoms in health personnel exposed to disinfectants

    African Journals Online (AJOL)

    2001-03-03

    Mar 3, 2001 ... East African Medical Journal Vol. 78 No. 3 March 2001. SYMPTOMS IN HEALTH PERSONNEL EXPOSED TO DISINFECTANTS. SW. Guthua, BDS, MMedSc, C.O.M.S. F.G. Macigo, BDS, MPH, Faculty of Dental Sciences, University of Nairobi, PO. Box 19676, Nairobi, D.L. Mwaniki, MPhil,. PhD and GO.

  13. Effective household disinfection methods of kitchen sponges

    Science.gov (United States)

    Several household disinfecting treatments to kill bacteria, yeasts and molds on kitchen sponges were evaluated. Sponges were soaked in 10 percent bleach for 3 min, lemon juice (pH 2.9) or deionized water for 1 min; placed in a microwave oven for 1 min; or placed in a dishwasher operating with a dryi...

  14. Effect Of Virkon Disinfectant Brand Of Potassium ...

    African Journals Online (AJOL)

    In the Nigerian market are many brands of disinfectants with varying efficacy against bacteria, fungi and viruses. Recently Virkon brand of potassium monoperoxysulphate (Antec, UK) was introduced. The Kelsey -Sykes test was carried out to determine the efficacy of Virkon against standard bacterial strains and ...

  15. The ozone as oxidising and disinfectant; El ozono como oxidante y desinfectante

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This document summarises the history, origin, characteristics and applications of ozone, a chemical element of growing interest and use in every sphere. This presentation seeks to provide an up-to-date overview of this reagent, which is being increasingly employed in both drinking and regenerated water treatment processes. It includes details of its great disinfectant capacity and its oxidising power, outperforming the other reagents usually applied to water. It supplies data on the effect ozone has on several micro-organisms in different operating conditions and on its effect on various chemical micro-contaminants, such as pesticides and metals. It also includes tables comparing it with other oxidising/disinfectant reagents. (Author)

  16. The role of surface disinfection in infection prevention.

    Science.gov (United States)

    Gebel, Jürgen; Exner, Martin; French, Gary; Chartier, Yves; Christiansen, Bärbel; Gemein, Stefanie; Goroncy-Bermes, Peter; Hartemann, Philippe; Heudorf, Ursel; Kramer, Axel; Maillard, Jean-Yves; Oltmanns, Peter; Rotter, Manfred; Sonntag, Hans-Günther

    2013-01-01

    The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed "The Role of Surface Disinfection in Infection Prevention". The most important findings and conclusions of this meeting are summarised in the present consensus paper. Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges. After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects. Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

  17. The response of aggregated Pseudomonas putida CP1 cells to UV-C and UV-A/B disinfection.

    Science.gov (United States)

    Maganha de Almeida, Ana C; Quilty, Bríd

    2016-11-01

    UV radiation is a spread method used worldwide for the disinfection of water. However, much of the research on the disinfection of bacterial cells by UV has focused on planktonic cells. Many bacterial cells in nature are present in clumps or aggregates, and these aggregates, which are more resistant to disinfection than their planktonic counterparts, can be problematic in engineered water systems. The current research used Pseudomonas putida (P. putida) CP1, an environmental and non-pathogenic microorganism which autoaggregates when grown under certain conditions, as a model organism to simulate aggregated cells. The study investigated the response of both the planktonic and the aggregated forms of the bacterium to UV-C (λ = 253.7 nm) and UV-A/B (λ > 300 nm) disinfection at laboratory scale in a minimal medium. The planktonic cells of P. putida CP1 were inactivated within 60 s by UV-C and in 60 min by UV-A/B; however, the aggregated cells required 120 min of UV-C treatment and 240 min of UV-A/B radiation to become inactive. The size of the aggregate was reduced following UV treatment. Although all the cells had lost culturability, viability as measured by the LIVE/DEAD® stain and epifluorescence microscopy was not completely lost and the cells all demonstrated regrowth after overnight incubation in the dark.

  18. Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system.

    Science.gov (United States)

    Baron, Julianne L; Vikram, Amit; Duda, Scott; Stout, Janet E; Bibby, Kyle

    2014-01-01

    Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.

  19. Evaluation and comparison of high-level microwave oven disinfection with chemical disinfection of dental gypsum casts.

    Science.gov (United States)

    Meghashri, K; Kumar, Prasanna; Prasad, D Krishna; Hegde, Rakshit

    2014-06-01

    The aim of this study was to evaluate and compare microwave disinfection with chemical disinfection of dental gypsum casts. A total of 120 casts were prepared from a silicone mold using Type III dental stone. Of the 120 casts, 60 casts were contaminated with 1 ml suspension of Staphylococcus aureus and 60 casts were contaminated with 1 ml suspension of Pseudomonas aeruginosa. Then, the casts were disinfected with microwave irradiation and chemical disinfection using the microwave oven and 0.5% sodium hypochlorite. Bacteriologic procedures were performed; the cfu/ml for each cast was calculated as a weighted mean. The results were analyzed using Kruskal-Wallis test and Mann-Whitney test. The untreated casts showed Brain heart infusion broth counts of 106 log cfu/ml compared to irradiated and chemically disinfected casts, in which 105 log reduction of cfu/ml was seen. These results satisfied the requirements of current infection control guidelines for the dental laboratory. The results obtained for chemical disinfection were in equivalence with microwave disinfection. Within the limitation of this in vitro study, it was found that microwave disinfection of casts for 5 min at 900 W gives high-level disinfection that complies with the current infection control guidelines for the dental laboratory and microwave disinfection method is an effective and validated method as chemical disinfection. How to cite the article: Meghashri K, Kumar P, Prasad DK, Hegde R. Evaluation and comparison of high-level microwave oven disinfection with chemical disinfection of dental gypsum casts. J Int Oral Health 2014;6(3):56-60 .

  20. Biological Treatment of Water Disinfection Byproducts using ...

    Science.gov (United States)

    Major disinfection by-products (DBPs) from the chlorination process of drinking water include trihalomethanes (THMs) and haloacetic acides (HAA5). THMs mainly consist of chloroform, and other harsh chemicals. Prolonged consumptions of drinking water containing high levels of THMs has been linked with diseases of the liver, kidneys, bladder, or central nervous system and may increase likelihood of cancer. A risk also exists for THMs exposure via inhalation while showering, bathing or washing clothes and dishes. Due to these risks, the U.S. EPA regulate THMs content in drinking water. This research investigates biological degradation of THM using chloroform as a model compound. The study aims to decrease possible risks of THMs through filtration. Throughout this year’s presentations, there is a common theme of health and safety concerns. UC researchers are working hard to clean water ways of naturally occurring contaminates as well as man-made toxins found in our waterways. The significance of these presentations translates into the promise of safer environments, and more importantly saved lives, as UC’s faculty continues to produce real-world solutions to problems threatening the world around us. A biotech process has been developed and demonstrated that effectively remove and treat volatile disinfection by-products from drinking water. The process strips low concentration disinfection by-products, such as trihalomethanes, that are formed during the chlori

  1. Airborne Microorganism Disinfection by Photocatalytic HEPA Filter

    Directory of Open Access Journals (Sweden)

    Rotruedee Chotigawin

    2010-07-01

    Full Text Available This study determined the efficacy of photocatalytic HEPA filters on microorganism disinfection in a closed-loop chamber and later applied it in an air purifier and tested its efficacy in an 8-m3 chamber and in a hospital. The photocatalytic filters were made by dip-coating a HEPA filter in a TiO2 slurry. In order to disinfect the microorganisms retained on the filter, UV-A light was irradiated onto the filter to create strong oxidative radicals which can destroy microorganisms. The findings showed that disinfection efficiency of the photocatalytic filters with high TiO2 loading was insignificantly higher than with lower loading. S. epidermidis was completely eliminated within 2 hours, while 86.8% of B. subtilis, 77.1% of A. niger, and 82.7% of P. citrinum were destroyed within 10 hours. When applying the photocatalytic filters into an air purifier in a 8-m3 chamber, it was found that as soon as the air purifier was turned on, 83.4% of S. epidermidis, 81.4% of B. subtilis, 88.5% of A. niger, and 75.8% of P. citrinum were removed from the air. In a hospital environment, the PCO air purifier efficacy was lower than that in the chamber. Besides, relative humidity, distances from the air purifier and room size were suspected to affect the efficacy of the photocatalytic filters.

  2. Evaluation of toothbrush disinfection via different methods

    Directory of Open Access Journals (Sweden)

    Adil BASMAN

    2016-01-01

    Full Text Available The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl, a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10. Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal–Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05. The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control. The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.

  3. Spiral-shaped reactor for water disinfection

    KAUST Repository

    Soukane, Sofiane

    2016-04-20

    Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria. The hydrodynamic behavior of contact tanks of different shapes, each with an approximate total volume of 50,000 m3, was analyzed by solving turbulent momentum transport equations with a computational fluid dynamics code, namely ANSYS fluent. Numerical experiments of a tracer pulse were performed for each design to generate flow through curves and investigate species residence time distribution for different inlet flow rates, ranging from 3 to 12 m3 s−1. A new nature-inspired Conch tank design whose shape follows an Archimedean spiral was then developed. The spiral design is shown to strongly outperform the other tanks’ designs for all the selected plug flow criteria with an enhancement in efficiency, less short circuiting, and an order of magnitude improvement in mixing and dispersion. Moreover, following the intensification philosophy, after 50% reduction in its size, the new design retains its properties and still gives far better results than the classical shapes.

  4. Effects of disinfectants in renal dialysis patients

    Energy Technology Data Exchange (ETDEWEB)

    Klein, E.

    1986-11-01

    Patients receiving hemodialysis therapy risk exposure to both disinfectants and sterilants. Dialysis equipment is disinfected periodically with strong solutions of hypochlorite or formaldehyde. Gross hemolysis resulting from accidental hypochlorite infusion has led to cardiac arrest, probably as a result of hyperkalemia. Formaldehyde is commonly used in 4% solutions to sterilize the fluid paths of dialysis controllers and to sterilize dialyzers before reuse. It can react with red cell antigenic surfaces leading to the formation of anti-N antibodies. The major exposure risk is the low concentration of disinfectant found in municipal water used to prepare 450 L dialysate weekly. With thrice-weekly treatment schedules, the quality requirements for water used to make this solution must be met rigorously. Standards for water used in the preparation of dialysate have recently been proposed but not all patients are treated with dialysate meeting such standards. The introduction of sterilants via tap water is insidious and has let to more pervasive consequences. Both chlorine and chloramines, at concentrations found in potable water, are strong oxidants that cause extensive protein denaturation and hemolysis. Oxidation of the Fe/sup 2 +/ in hemoglobin to Fe/sup 3 +/ forms methemoglobin, which is incapable of carrying either O/sub 2/ or CO/sub 2/. Chloramine can form not only methemoglobin, but can also denature proteins within the red cell, thus forming aggregates (Heinz bodies). Chloramines also inhibit hexose monophosphate shunt activity, a mechanism that makes the red cell even more susceptible to oxidant damage.

  5. Role of disinfection in the Infection Prevention Multibarrier System

    OpenAIRE

    Kramer, Axel

    2007-01-01

    The role of disinfection in infection prevention has been analyzed over the past 50 years both in the form of benefit-risk evaluations as well as in an epidemiological sense. This has served as the basis for not only national and international guidelines and recommendations, but has also created the legal and normative framework for regulation of infection control (and hence of disinfection) in numerous and acts and ordinances. Likewise, today the efficacy of disinfection measures, user safet...

  6. Influence of ultrasound enhancement on chlorine dioxide consumption and disinfection by-products formation for secondary effluents disinfection.

    Science.gov (United States)

    Zhou, Xiaoqin; Zhao, Junyuan; Li, Zifu; Lan, Juanru; Li, Yajie; Yang, Xin; Wang, Dongling

    2016-01-01

    Chlorine dioxide (ClO2) has been promoted as an alternative disinfectant because of its high disinfection efficiency and less formation of organic disinfection by-products (DBPs). However, particle-associated microorganisms could be protected during the disinfection process, which decreases the disinfection efficiency or increases the required dosage. Besides, the formation of inorganic disinfection by-products is a significant concern in environment health. Ultrasound (US)-combined disinfection methods are becoming increasingly attractive because they are efficient and environmentally friendly. In this study, US was introduced as an enhancement method to identify its influence on ClO2 demand reduction and to minimize the production of potential DBPs for secondary effluents disinfection. Fecal coliform was used as an indicator, and DBPs, including trichloromethane (TCM), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), chlorite (ClO2(-)), and chlorate (ClO3(-)), were analyzed to observe the potential DBPs formation. Results show that US pretreatment could reduce half of ClO2 dosage compared with ClO2 disinfection alone for the same disinfection efficiency, and that an input power density of 2.64 kJ/L pretreatment with the 1.5mg/L ClO2 was enough to meet the discharge requirement in China (i.e., fecal coliform below 1000 CFU/L for Class 1A) for secondary effluent disinfection, and the ClO2(-) concentration in the disinfection effluent was only 1.37 mg/L at the same time. Furthermore, the different effects of US on the two processes (US as pretreatment and simultaneous US/ClO2 disinfection) were also analyzed, including deagglomerating, cell damage, and synergistic disinfection as well as degasing/sonolysis. It was proved that the production of TCM, DCAA, and TCAA was insignificantly influenced with the introduction of US, but US pretreatment did reduce the production of ClO2(-) and ClO3(-) effectually. In general, US pretreatment could be a better option for

  7. Silver-based Antibacterial Surfaces for Drinking Water Disinfection - An overview

    Science.gov (United States)

    Risks associated with current disinfection techniques, including the formation of disinfection by-products and multi-drug resistant bacterial species, have prompted the exploration of advanced disinfection methods. One such technique employs silver nanoparticles incorporation on ...

  8. Dating as leisure

    OpenAIRE

    Flambard, Véronique; Vaillant, Nicolas Gérard; Wolff, François-Charles

    2010-01-01

    Partner selection occurs naturally and informally, but it may also be organized through commercial intermediaries facilitating mating and dating. This paper focuses on the relationship between online dating and the business cycle . We rely on monthly data covering the period from January 2004 to August 2008 on the demand for online dating in France to study whether economic recession tends to stimulate the online dating industry. We find that during economic downturns, people tend to to incre...

  9. Electrochemical disinfection of dental implants--a proof of concept

    National Research Council Canada - National Science Library

    Mohn, Dirk; Zehnder, Matthias; Stark, Wendelin J; Imfeld, Thomas

    2011-01-01

    .... An unexpected approach to implant disinfection may evolve from electrolysis. Given the electrical conductivity of titanium implants, alkalinity or active oxidants can be generated in body fluids...

  10. Hydrogen peroxide as an effective disinfectant for Pasteurella multocida.

    Science.gov (United States)

    Jung, In-Soo; Kim, Hyun-Jung; Jung, Won-Yong; Kim, Chan-Wha

    2014-07-01

    Pasteurella multocida (P. multocida) infections vary widely, from local infections resulting from animal bites and scratches to general infections. As of yet, no vaccine against P. multocida has been developed, and the most effective way to prevent pathogenic transmission is to clean the host environment using disinfectants. In this study, we identified which disinfectants most effectively inhibited environmental isolates of P. multocida. Three readily available disinfectants were compared: 3% hydrogen peroxide (HP), 70% isopropyl alcohol, and synthetic phenol. In suspension tests and zone inhibition tests, 3% HP was the most promising disinfectant against P. multocida.

  11. Evaluation of disinfection techniques in the treatment of advanced primary treated wastewater for Ciudad Juárez, México.

    Science.gov (United States)

    Carrasco, Leirad; Turner, Charles D

    2006-01-01

    The purpose of this study was to develop and evaluate the effectiveness of alternative disinfection techniques at the bench-scale level using wastewater from Ciudad Juarez, Mexico, as model feed. This paper presents findings on the effectiveness of UV radiation, peracetic acid (PAA), chlorine dioxide (ClO2), and hypochlorous acid (HOCl) as disinfectants for advanced primary treatment (APT) plant effluent. Wastewater samples for bench-scale testing were collected from an agua negra ("black water") ditch that is part of the combined sewer system in Ciudad Juarez. Bench-scale simulations of the APT process used in Ciudad Juarez were run using a jar test apparatus and aluminum sulfate [Al2(SO4)3] as the coagulant. Jar test effluent from the bench system was used for disinfection testing. The Mexican discharge quality standard for total coliforms is 10 000/100 mL. Ultraviolet radiation met this standard at a dose of 47.5 mW-s/cm2. Ultraviolet disinfection proved reliable and effective despite the presence of suspended solids, and UV dose effectiveness expressed as a total coliforms survival ratio was best explained by a linear regression model. The ClO2 dose ranged from 10 to 20 mg/L and was only effective under ambient temperature conditions found during the winter months; PAA disinfection never met Mexican standards. Chlorine disinfection was effective at a dose range of 8 to 10 mg/L on samples collected at low temperature conditions. Since the completion of this research, Ciudad Juarez has discontinued the use of chlorine disinfection because of its high cost and ineffectiveness.

  12. Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region

    Energy Technology Data Exchange (ETDEWEB)

    Ndounla, J., E-mail: juliette.ndounla@epfl.ch [Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, CH 1015 Lausanne (Switzerland); Institut International d' Ingénierie de l' Eau et de l' Environnement, Laboratoire Eau, Dépollution, Ecosystème et Santé (LEDES), 01 BP 594 Ouagadougou 01 (Burkina Faso); Pulgarin, C., E-mail: Cesar.pulgarin@epfl.ch [Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, CH 1015 Lausanne (Switzerland)

    2014-09-15

    The photo-disinfection of water from two different wells (W1, pH: 4.6–5.1 ± 0.02) and (W2 pH: 5.6–5.7 ± 0.02) was carried out during the rainy season at Ouagadougou–Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24 h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO{sub 3}{sup −} concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO{sub 3}{sup −} concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and

  13. Photoelectrocatalytic disinfection of water and wastewater: performance evaluation by qPCR and culture techniques.

    Science.gov (United States)

    Venieri, Danae; Chatzisymeon, Efthalia; Politi, Eleonora; Sofianos, Spiridon S; Katsaounis, Alexandros; Mantzavinos, Dionissios

    2013-03-01

    Photoelectrocatalytic oxidation (PEC) was evaluated as a disinfection technique using water and secondary treated wastewater spiked with Escherichia coli and Enterococcus faecalis. PEC experiments were carried out using a TiO(2)/Ti-film anode and a zirconium cathode under simulated solar radiation. Bacterial inactivation was monitored by culture and quantitative polymerase chain reaction (qPCR). Inactivation rates were enhanced when the duration of the treatment was prolonged and when the bacterial density and the complexity of the water matrix were decreased. E. coli cells were reduced by approximately 6 orders of magnitude after 15 min of PEC treatment in water at 2V of applied potential and an initial concentration of 10(7) CFU/mL; pure photocatalysis (PC) led to about 5 log reduction, while electrochemical oxidation alone resulted in negligible inactivation. The superiority of PEC relative to PC can be attributed to a more efficient separation of the photogenerated charge carriers. Regarding disinfection in mixed bacterial suspensions, E. coli was more susceptible than E. faecalis at a potential of 2V. The complex composition of wastewater affected disinfection efficiency, yielding lower inactivation rates compared to water treatment. qPCR yielded lower inactivation rates at longer treatment times than culture techniques, presumably due to the fact that the latter do not take into account the viable but not culturable state of microorganisms.

  14. Solar disinfection: an approach for low-cost household water treatment technology in Southwestern Ethiopia.

    Science.gov (United States)

    Dessie, Awrajaw; Alemayehu, Esayas; Mekonen, Seblework; Legesse, Worku; Kloos, Helmut; Ambelu, Argaw

    2014-01-10

    Disinfection of contaminated water using solar radiation (SODIS) is known to inactivate bacteria. Its inactivation efficiency depends on local conditions where the disinfection is made. This study was aiming to test the efficiency of solar disinfection using different water parameters as low-cost household water treatment technology. Inactivation of microbes was tested using fecal coliform as test organism. The SODIS experiment was carried out at turbidity 2NTU, pH 7, and various water temperature (38.1°C, 41.8°C, 45.6°Cand 51.1°C) and solar intensities, using clear and black plastic bottles filled to different depths. The results show that the rate of microbial inactivation in relation to depth of water, turbidity, container type, intensity of light and color of container was statistically significant (p SODIS could play a significant role in the provision of safe water in rural communities of developing countries where there is ample sunshine, specifically in sub-Saharan African countries.

  15. Comparison of the Effect of Perchlorine, Sodium Hypochlorite, and Electrochemical Method on Disinfection of Vegetables

    Directory of Open Access Journals (Sweden)

    Hassan Hashemi

    2017-09-01

    Conclusion: With increasing concentrations of disinfectants dose, inactivation of bacteria was done in less time. Electrochemical method is the suitable option to disinfect vegetables at home and emergencies.

  16. Roof-harvested rainwater for potable purposes: application of solar disinfection (SODIS) and limitations.

    Science.gov (United States)

    Amin, Muhammad Tahir; Han, Mooyoung

    2009-01-01

    Efficiency of solar disinfection (SODIS) was evaluated for the potability of rainwater in view of the increasing water and energy crises especially in developing countries. Rainwater samples were collected from an underground storage tank in 2 L polyethylene terephthalate (PET) bottles and SODIS efficiency was evaluated at different weather conditions. For optimizing SODIS, PET bottles with different backing surfaces to enhance the optical and thermal effects of SODIS were used and different physicochemical parameters were selected and evaluated along with microbial re-growth observations and calculating microbial decay constants. Total and fecal coliforms were used along with Escherichia Coli and Heterotrophic Plate Counts (HPC) as basic microbial and indicator organisms of water quality. For irradiance less than 600 W/m(2), reflective type PET bottles were best types while for radiations greater than 700 W/m(2), absorptive type PET bottles offered best solution due to the synergistic effects of both thermal and UV radiations. Microbial inactivation did not improve significantly by changing the initial pH and turbidity values but optimum SODIS efficiency is achieved for rainwater with acidic pH and low initial turbidity values by keeping air-spaced PET bottles in undisturbed conditions. Microbial re-growth occurred after one day only at higher turbidity values and with basic pH values. First-order reaction rate constant was in accordance with recent findings for TC but contradicted with previous researches for E. coli. No microbial parameter met drinking water guidelines even under strong experimental weather conditions rendering SODIS ineffective for complete disinfection and hence needed more exposure time or stronger sunlight radiations. With maximum possible storage of rainwater, however, and by using some means for accelerating SODIS process, rainwater can be disinfected and used for potable purposes.

  17. Disinfection for infection prevention over the course of time

    Science.gov (United States)

    Hell, M.; Pauser, G.

    2007-01-01

    In recent years and decades increasingly more emphasis has been placed on alcohol-based solutions for hygienic and surgical hand disinfection. Traditional handwashing with soap and water has been largely replaced in the everyday clinical setting, as has the use of disinfectant soap-based solutions for surgical hand disinfection. It has been possible in recent years to reduce the exposure time for alcohol-based hand disinfection in surgery from 5 to 3 minutes, and there are plans to reduce this even further. The growing awareness of the tolerability issues has also given rise to favorable developments here. There have also been dramatic changes in preoperative skin disinfection. The non-alcoholic solutions with a slow onset of action (e.g. iodophors) have been virtually replaced by alcohol-based solutions of demonstrated efficacy. Non-alcoholic solutions continue to be used for disinfection of mucous membranes, but iodine-based products are being phased out here. The term “instrument disinfection” has been largely supplanted now by the expression “instrument reprocessing or medical device decontamination” (which is also underpinned by legislation) and it takes account of the trend towards thermal disinfection. Meticulous cleaning is thus an indispensable precondition for sterilization, which normally follows disinfection. The greatest lack of consensus at European level relates to surface disinfection. Routine, parallel cleaning and disinfection of all surfaces close to and remote from the patient is being increasingly replaced by selective disinfection, whenever warranted, of surfaces close to the patient. The problem here is that medical personnel continue to view cleaning and disinfection as interchangeable tasks. This situation is further compounded by the fact that hospitals are finding it increasingly more difficult to assure adequately successful cleaning and disinfection outcomes. To ensure effective infection control, cleaning and disinfection of

  18. Effects of biofilm formation on haemodialysis monitor disinfection.

    Science.gov (United States)

    Cappelli, Gianni; Sereni, Luisa; Scialoja, Maria Grazia; Morselli, Massimo; Perrone, Salvatore; Ciuffreda, Angela; Bellesia, Massimo; Inguaggiato, Paola; Albertazzi, Alberto; Tetta, Ciro

    2003-10-01

    Biofilms are composed of communities of micro-organisms adhering to essentially any surface. We evaluated whether biofilm formation in the hydraulic circuit of a purposely contaminated haemodialysis monitor would modify the efficacy of different disinfection modalities against bacteria and endotoxin concentrations. A water-borne Pseudomonas aeruginosa (109) suspension was recirculated for 1 h and was left standing for 72 h (stationary phase) in the hydraulic circuit of the monitor. The monitor was then washed and disinfected by different physical (heat, 85 degrees C) or chemical (hypochlorite or peracetic acid) disinfection modalities (protocol A). In protocol B, the bacterial suspension was also recirculated for 1 h, but the monitor was then immediately washed and disinfected by different chemical disinfection modalities (hypochlorite or peracetic acid). Biofilm formation was revealed by scanning and confocal laser electron microscopy after the stationary phase (protocol A), but was absent when the monitor was immediately washed and disinfected (protocol B). In the presence of biofilm (protocol A), heat in association with citric acid was the most effective modality for reducing both colony forming units and endotoxin concentrations, whereas heat by itself was the least effective method of disinfection. Dwelling (60 h) with diluted peracetic acid completely prevented the formation of biofilm. In the absence of biofilm (protocol B), chemical disinfection proved to be effective against both colony forming units and endotoxin concentrations. We found that biofilm formation may markedly reduce the efficacy of presently available disinfection modalities. Therefore, different disinfection modalities and the combined action of descaling (by citric acid) and disinfection (physical/chemical agents) should be used periodically in haemodialysis monitors. In addition, dwelling with diluted peracetic acid should be adopted whenever monitors are not in use.

  19. Effects of ionizing radiation on papayas ( Carica papaya ) fruit | Orji ...

    African Journals Online (AJOL)

    The effects of ionizing radiation on papaya fruits were investigated with a particular interest on the disinfection and ripening. Twelve samples of papayas fruit, each weighing between 400 – 450 g were irradiated over four different regimes of radiation doses: 0.25, 0.50, 0.75 and 1.00 kGy, using a cobalt-60 gamma irradiation ...

  20. 9 CFR 71.11 - Cresylic disinfectant as permitted disinfectant; specifications.

    Science.gov (United States)

    2010-01-01

    ... disinfectant; specifications. 71.11 Section 71.11 Animals and Animal Products ANIMAL AND PLANT HEALTH...; specifications. The following specifications will be employed for determining the suitability of cresylic... of distilled water at 25 °C. (77 °F.) within 2 minutes (solution-rate test), producing a solution...

  1. [Genotoxicity of drinking water during chlorine and chloramine disinfection and the influence of disinfection conditions using the umu-test].

    Science.gov (United States)

    Liu, Qing; Zhang, Li-Ping; Liu, Wen-Jun; Nie, Xue-Biao; Zhang, Su-Xia; Zhang, Shun

    2010-01-01

    In this study, the effects of disinfectant dosage, reaction time and the ratio of Cl2 to N of disinfectant on genotoxicity of effluent of ozone-biological activated carbon (O3-BAC) during chlorine or chloramine disinfection were investigated using umu-test. It was found that, the genotoxicity of effluent of O3-BAC before disinfection ranged from 20-70 ng/L, and it increased after disinfection by chlorine or chloramines. With the same reaction time(24 h), genotoxicity after chlorination (40-95 ng/L) was higher than that after chloramination (20-40 ng/L) under same initial dosage. For chlorination, with initial dosage increasing from 0 mg/L to 10 mg/L, genotoxicity increased firstly, and got the maximum value at about 0.5-1 mg/L dosage, then decreased and got the minimum value at about 3-5 mg/L dosage, and finally increased again. For chloramination, genotoxicity didn't change that much. With the dosage of 3 mg/L and reaction time increasing from 0 h to 72 h, no matter for chlorine or chloramines disinfection, genotoxicity of effluent of O3-BAC both increased firstly, and got the maximum value at about 2 h, then decreased and got the minimum value at about 18 h, and finally increased again, and genotoxicity after chlorine disinfection (83-120 ng/L) was higher than that after chloramines disinfection (20-62 ng/L) under same reaction time. Further more, effects of the different ratios of Cl2 to N of disinfectant on genotoxicity of effluent of O3-BAC were also studied. Results of this study demonstrate that under test conditions, chloramine disinfection is safer than chlorine disinfection in the aspect of genotoxicity for drinking water, and the changes of genotoxicity are different from those of total HAAs.

  2. Correlates of minimal dating.

    Science.gov (United States)

    Leck, Kira

    2006-10-01

    Researchers have associated minimal dating with numerous factors. The present author tested shyness, introversion, physical attractiveness, performance evaluation, anxiety, social skill, social self-esteem, and loneliness to determine the nature of their relationships with 2 measures of self-reported minimal dating in a sample of 175 college students. For women, shyness, introversion, physical attractiveness, self-rated anxiety, social self-esteem, and loneliness correlated with 1 or both measures of minimal dating. For men, physical attractiveness, observer-rated social skill, social self-esteem, and loneliness correlated with 1 or both measures of minimal dating. The patterns of relationships were not identical for the 2 indicators of minimal dating, indicating the possibility that minimal dating is not a single construct as researchers previously believed. The present author discussed implications and suggestions for future researchers.

  3. Improved Drinking Water Disinfection with UVC-LEDs for Escherichia Coli and Bacillus Subtilis Utilizing Quartz Tubes as Light Guide

    Directory of Open Access Journals (Sweden)

    Andrej Gross

    2015-08-01

    Full Text Available A new approach is investigated utilizing light guidance capabilities of optical pure quartz glass in order to maximize drinking water disinfection efficiency with UVC-light-emitting diodes (LEDs. Two experimental setups consisting of soda-lime AR® glass (VWR, Darmstadt, Germany or HSQ® 100 quartz glass (Heraeus, Wasserburg, Germany reactors were designed to compare disinfection rates with and without total reflection of UVC radiation along the reactor walls. Each reactor was filled with 9 mL bacteria samples containing either E. coli DSM (Deutsche Sammlung von Mikroorganismen 498 or B. subtilis DSM 402 strains (concentration 1–3 × 106 colony forming units (CFU/mL with and without additional mixing and irradiation periods of 10, 40, and 90 s. Disinfection rates were increased up to 0.95 log10 (E. coli and 0.75 log10 (B. subtilis by the light guide approach in stagnant samples. The same experiments with mixing of the samples resulted in an increased disinfection efficiency of 3.07 log10 (E. coli and 1.59 log10 (B. subtilis. Optical calculations determine that total reflection is achieved with the applied UVC-LED’s viewing angle of 15°. Furthermore measurements show that HSQ® 100 quartz has a transmittance of 92% at 280 nm UVC irradiation compared to the transmittance of soda-lime glass of 2% (1 mm wall thickness.

  4. Calibrating an optimal condition model for solar water disinfection in peri-urban household water treatment in Kampala, Uganda.

    Science.gov (United States)

    Okurut, Kenan; Wozei, Eleanor; Kulabako, Robinah; Nabasirye, Lillian; Kinobe, Joel

    2013-03-01

    In low income settlements where the quality of drinking water is highly contaminated due to poor hygienic practices at community and household levels, there is need for appropriate, simple, affordable and environmentally sustainable household water treatment technology. Solar water disinfection (SODIS) that utilizes both the thermal and ultra-violet effect of solar radiation to disinfect water can be used to treat small quantities of water at household level to improve its bacteriological quality for drinking purposes. This study investigated the efficacy of the SODIS treatment method in Uganda and determined the optimal condition for effective disinfection. Results of raw water samples from the study area showed deterioration in bacteriological quality of water moved from source to the household; from 3 to 36 cfu/100 mL for tap water and 75 to 126 cfu/100 mL for spring water, using thermotolerant coliforms (TTCs) as indicator microorganisms. SODIS experiments showed over 99.9% inactivation of TTCs in 6 h of exposure, with a threshold temperature of 39.5 ± 0.7°C at about 12:00 noon, in the sun during a clear sunny day. A mathematical optimal condition model for effective disinfection has been calibrated to predict the decline of the number of viable microorganisms over time.

  5. Zero-G Condensing Heat Exchanger with Integral Disinfection

    Science.gov (United States)

    Burke, Kenneth A. (Inventor)

    2012-01-01

    The system that operates in a zero gravity environment and has an integral ozone generating capability is disclosed. The system contributes to the control of metabolic water vapors in the air, and also provided disinfection of any resulting condensate within the system, as well as disinfection of the air stream that flows throughout the disclosed system.

  6. [Scanning electron microscope study of chemically disinfected endodontic files].

    Science.gov (United States)

    Navarro, G; Mateos, M; Navarro, J L; Canalda, C

    1991-01-01

    Forty stainless steel endodontic files were observed at scanning electron microscopy after being subjected to ten disinfection cycles of 10 minutes each one, immersed in different chemical disinfectants. Corrosion was not observed on the surface of the files in circumstances that this study was made.

  7. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  8. The Viral Efficacy of three Disinfectants on Hepatitis B virus

    Directory of Open Access Journals (Sweden)

    Arami Sakineh

    2015-01-01

    Full Text Available   Background and Aims: Hepatitis B is an important infection route in dentistry requiring different disinfectants to prevent its transmission. The aim of this study was to compare the effects of chemical disinfectants (FD366, ISORAPID and 5% sodium hypochlorite 2/100 to remove Hepatitis B infections from the dental surfaces.   Materials and Methods: In this experimental laboratory trial, serum of 10 HBV patients was poured into microtubes, FD366, ISORAPID and hypochlorite disinfectants were added to them. PCR experiments with viral diagnostic kits were used to diagnose the virus genome. Real time PCR was used to evaluate after incubation with the disinfectants. The reductions occurred in the viral load of Hepatitis B were statistically analyzed using Kruskal-wallis and Mann-Whitney U tests .   Results: No significant antiviral efficacy was noted following the application of FD366 and ISORAPID disinfectants (P=0/07. However, hypochlorite showed the most efficacy to disinfect Hepatitis B and a significant difference was found among them (P<0.0001.   Conclusion: Under the study limitations, FD366 and ISORAPID disinfectants did not show adequate efficacy to remove Hepatitis B virus. Hypochlorite was the most effective disinfectant.

  9. Sewage disinfection towards protection of drinking water resources.

    Science.gov (United States)

    Kolch, A

    2000-01-01

    Wastewater applied in agriculture for irrigation could replace the use of natural drinking-water resources. With respect to high concentrations of human pathogens wastewater has to be disinfected prior to use. This paper introduces disinfection methods with emphasis on UV irradiation.

  10. Wide variation in effectiveness of laboratory disinfectants against bacteriophages.

    Science.gov (United States)

    Halfhide, D E; Gannon, B W; Hayes, C M; Roe, J M

    2008-12-01

    The purpose of this study was to identify an effective disinfectant for the inactivation of the bacteriophages (phages) being used in our laboratory, as published studies on phage inactivation are far from unanimous in their conclusions. The phages studied were three closely related strains of Myoviridae and three strains of Siphoviridae. Three disinfectants which are used commonly in microbiology laboratories were evaluated: Virkon (1%), ethanol (75%) and sodium hypochlorite (2500 ppm available chlorine). The most effective of these was Virkon, which inactivated all six phages rapidly. Ethanol was effective against the Myoviridae but had little effect on the Siphoviridae. Sodium hypochlorite was the least effective of the disinfectants evaluated. The findings of this study demonstrate a wide diversity in the effectiveness of disinfectants tested for inactivation of phages. Of the disinfectants tested Virkon is the most suitable choice for those unable to carry out disinfection validation studies, or where a broad spectrum disinfectant against phages is required. All of the phages in this study showed resilience to inactivation by sodium hypochlorite, and therefore this disinfectant is an unwise choice for use against phage without first assessing its effectiveness.

  11. A biocoagulant slow sand filtration for disinfection of Toxoplasma ...

    African Journals Online (AJOL)

    Considering that is widely used for various domestic chores; filtration disinfection of T. gondii was considered. A bench scale disinfection of oocysts of T. gondii with 0.2 g of powdered Moringa oleifera seeds per 10 ml of contaminated water from Mezam River showed a reduction of 50 oocysts per 10 ml to 10 oocysts in 15 ...

  12. 40 CFR 141.65 - Maximum residual disinfectant levels.

    Science.gov (United States)

    2010-07-01

    ... following as the best technology, treatment techniques, or other means available for achieving compliance... treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce.... 141.65 Section 141.65 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER...

  13. In vitro antimicrobial activity of three new generation disinfectants ...

    African Journals Online (AJOL)

    Purpose: To determine the efficacies of three commercially available new generation disinfectants against some bacteria and yeast. Methods: Three commercially available new generation disinfectant (0.2 % chlorine dioxide, 0.3 % chlorine dioxide and 50 % hydrogen peroxide-stabilized by colloidal silver) were screened ...

  14. In vitro antimicrobial activity of three new generation disinfectants

    African Journals Online (AJOL)

    It has broad spectrum of activity against bacteria, viruses, protozoan cysts, algae and animal planktons, both dissolved in water and gas phase. Its bactericidal activity remains constant over a broader pH range from pH 3 to 8. ClO2 has been used for many disinfection procedures such as water disinfection. In water, chlorine.

  15. Effects of disinfectants in renal dialysis patients.

    Science.gov (United States)

    Klein, E

    1986-01-01

    Patients receiving hemodialysis therapy risk exposure to both disinfectants and sterilants. Dialysis equipment is disinfected periodically with strong solutions of hypochlorite or formaldehyde. More recently, reuse of dialyzers has introduced the use of additional sterilants, such as hydrogen peroxide and peracetic acid. The use of these sterilants is recognized by the center staffs and the home patient as a potential risk, and residue tests are carried out for the presence of these sterilants at the ppm level. Gross hemolysis resulting from accidental hypochlorite infusion has led to cardiac arrest, probably as a result of hyperkalemia. Formaldehyde is commonly used in 4% solutions to sterilize the fluid paths of dialysis controllers and to sterilize dialyzers before reuse. It can react with red cell antigenic surfaces leading to the formation of anti-N antibodies. Such reactions probably do not occur with hypochlorite or chloramines. The major exposure risk is the low concentration of disinfectant found in municipal water used to prepare 450 L dialysate weekly. With thrice-weekly treatment schedules, the quality requirements for water used to make this solution must be met rigorously. Standards for water used in the preparation of dialysate have recently been proposed but not all patients are treated with dialysate meeting such standards. The introduction of sterilants via tap water is insidious and has led to more pervasive consequences. Both chlorine and chloramines, at concentrations found in potable water, are strong oxidants that cause extensive protein denaturation and hemolysis. Oxidation of the Fe2+ in hemoglobin to Fe3+ forms methemoglobin, which is incapable of carrying either O2 or CO2.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3816735

  16. Dating the Crucifixion

    Science.gov (United States)

    Humphreys, Colin J.; Waddington, W. G.

    1983-12-01

    The date of the Crucifixion has been debated for many years, but there has been no agreement on the year nor the day. Astronomical calculations have now been used to reconstruct the Jewish calendar in the first century AD and to date a lunar eclipse that biblical and other references suggest followed the Crucifixion. The evidence points to Friday 3 April AD 33 as the date when Jesus Christ died.

  17. Disinfection of contaminated water by using solar irradiation.

    Science.gov (United States)

    Caslake, Laurie F; Connolly, Daniel J; Menon, Vilas; Duncanson, Catriona M; Rojas, Ricardo; Tavakoli, Javad

    2004-02-01

    Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min.

  18. Recent advances in drinking water disinfection: successes and challenges.

    Science.gov (United States)

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  19. ESR dating of fault rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2003-02-15

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene.

  20. The role of surface disinfection in infection prevention

    Directory of Open Access Journals (Sweden)

    Gebel, Jürgen

    2013-04-01

    Full Text Available [english] Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper.Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges.Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects.Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

  1. Killing of Gyrodactylus salaris by heat and chemical disinfection.

    Science.gov (United States)

    Koski, Perttu; Anttila, Pasi; Kuusela, Jussi

    2016-03-23

    Gyrodactylus salaris is a monogenean, which has collapsed tens of wild Atlantic salmon populations. One of the means of preventing the spread of the parasite is the disinfection of the fishing equipment, which is used in the rivers having susceptible salmon populations. Little is known about the dosage of disinfectants against G. salaris. There are not standards for the testing of disinfectants against multicellular parasites. The present investigation developed a method to test disinfectants and examined the effectiveness of heated water and a commercially available disinfectant (Virkon S) in killing G. salaris. Individual G. salaris worms were followed under the microscope during treatment with heated water or Virkon S disinfectant blend. The logarithm of the time needed to kill the parasite was used as a dependent variable in linear regression. The upper 99.98 % prediction line for the dependent variable was used to obtain a value resembling the time needed for a 4 log reduction of the microbial pathogen, which is commonly used as a criterion for disinfectants. Also 6 log reduction was applied. Exposure to a relatively low temperature was found to kill the parasite. Even 5-50 min treatment (=10-100 times the 99.98 % upper prediction value) with heated water at 40 °C might be used. This would enable the utilisation of hot tap water in the disinfection of fishing gear. The present practice of 1 % Virkon S for 15 min was also found to kill the parasite. The follow-up of single parasites of a test population and the use of the calculated upper predictive line in the regression analysis offers a method to analyse the effects of disinfectants on parasites like G. salaris. The results of our tests give possibilities for using disinfection methods, which may be more acceptable by the fishermen than the present ones.

  2. Understanding Teen Dating Violence

    Science.gov (United States)

    ... public health problems like dating violence. Step 1: Define the problem Before we can prevent dating violence, we need ... and who it affects. CDC learns about a problem by gathering and studying ... and supports research to answer this question. Step 3: Develop and ...

  3. Date Palm Germplasm

    Science.gov (United States)

    This book chapter reviews date palm genetic resources and their conservation. Date palm (Phoenix dactylifera) is an important food crop in the Middle East and North Africa. Its center of origin and diversity most probably is the area near Iraq/Iran. From there, it spread throughout its present range...

  4. Dating and Sexual Feelings

    Science.gov (United States)

    ... sex It’s not too late to stop having sex Could I be gay? Dating older guys Staying safe when dating What about masturbation? What teens are saying about sex top You may get lots of messages about ...

  5. Second Quaternary dating workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  6. Efficacy of select disinfectants at inactivating Ranavirus.

    Science.gov (United States)

    Bryan, Laura K; Baldwin, Charles A; Gray, Matthew J; Miller, Debra L

    2009-04-06

    Ranavirus can cause disease in reptiles and amphibians. Because survival time outside of a host remains uncertain, equipment must be disinfected to prevent transmission of ranaviruses. However, disinfectant efficacy against amphibian ranaviruses has not been investigated for chlorhexidine (Nolvasan), sodium hypochlorite (bleach), or potassium compounds. Our goal was to determine the efficacy of Nolvasan (0.25, 0.75 and 2.0%), bleach (0.2, 1.0, 3.0 and 5.0%), and Virkon S (1.0%) at inactivating Ranavirus at 1 and 5 min contact durations. Potassium permanganate (KMnO4) (2.0 and 5.0 ppm) was also tested with a 60 min contact time. Nolvasan at 0.75 and 2.0% and bleach at 3.0 and 5.0% concentration were effective for both contact durations. Virkon S was effective for both durations, but KMnO4 was not effective at either concentration. Concentrations of Nolvasan, bleach and Virkon S that are at least 0.75, 3.0 and 1.0%, respectively, are effective at inactivating Ranavirus after 1 min exposure time.

  7. Fine Sprays for Disinfection within Healthcare

    Directory of Open Access Journals (Sweden)

    G Nasr

    2016-09-01

    Full Text Available Problems exist worldwide with Hospital Acquired Infections (HAI's. The Spray Research Group (SRG have been working with relevant industries in developing a product which can provide a delivery system for treatment chemicals for surfaces, including the design and testing of a novel Spill-Return Atomiser (SRA for this purpose. A comprehensive description of this atomiser has already been given. This paper reports on a new application of this atomiser and discusses the problem of spray coating for disinfection that has been considered very little in previous work. The related spray coating performance tests in developing the product are thus provided. The experimental work includes determining the required spray duration and the coverage area produced by different sprays, including the analysis of the effects of atomiser positions, configurations, and the required number of atomisers. Comparison is made with the efficacy of an ultrasonic gas atomiser that is currently used for this purpose. The investigation has found that the utilisation of fine sprays (10μm>D32>25μm at high liquid pressure (<12MPa and low flow rates (<0.3 l/min is suitable for surface disinfection in healthcare applications (i.e. MRSA, VRSA etc.

  8. Quality control of disinfection in ultrasonic baths

    Energy Technology Data Exchange (ETDEWEB)

    Schoene, H. [Technical University Dresden (Germany). Faculty of Mechanical Engineering; Jatzwauk, L. [University Hospital of the Technical University Dresden (Germany). Abt. Krankenhaushygiene

    2002-07-01

    Numerous investigations under laboratory conditions confirmed the microbicidal efficacy of ultrasonication. Morphological destruction was shown on bacteria and fungi as well as on different virus species. Ultrasonic treatment seems to increase the effect of different antibiotics and disinfectants. Reasons for this synergism are largely unknown and uninvestigated, but the active principle seems to bee the dispersing effect of ultrasonication in combination with the destruction of cell wall or cell membrane. Unfortunately no validation of test conditions exists for most of these investigations, regarding intensity and frequency of ultrasonic waves, temperature of liquid medium and measurement of cavitation which is an essential part of physical and chemical effects in ultrasonic baths. In contrast to most laboratory experiments sound density of ultrasound for treatment of medical instruments is below 1 W/cm{sup 2} because instruments will be destroyed under stronger ultrasonic conditions. The frequency is below 50 KHz. This paper describes bactericidal and fungicidal effects of low- intensity-ultrasonication and its synergistical support to chemical disinfection. (orig.)

  9. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Science.gov (United States)

    2010-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§ 141...

  10. UV/TiO2 photocatalytic disinfection of carbon-bacteria complexes in activated carbon-filtered water: Laboratory and pilot-scale investigation.

    Science.gov (United States)

    Zhao, Jin Hui; Chen, Wei; Zhao, Yaqian; Liu, Cuiyun; Liu, Ranbin

    2015-01-01

    The occurrence of carbon-bacteria complexes in activated carbon filtered water has posed a public health problem regarding the biological safety of drinking water. The application of combined process of ultraviolet radiation and nanostructure titanium dioxide (UV/TiO2) photocatalysis for the disinfection of carbon-bacteria complexes were assessed in this study. Results showed that a 1.07 Lg disinfection rate can be achieved using a UV dose of 20 mJ cm(-2), while the optimal UV intensity was 0.01 mW cm(-2). Particle sizes ≥8 μm decreased the disinfection efficiency, whereas variation in particle number in activated carbon-filtered water did not significantly affect the disinfection efficiency. Photoreactivation ratio was reduced from 12.07% to 1.69% when the UV dose was increased from 5 mJ cm(-2) to 20 mJ cm(-2). Laboratory and on-site pilot-scale experiments have demonstrated that UV/TiO2 photocatalytic disinfection technology is capable of controlling the risk posed by carbon-bacteria complexes and securing drinking water safety.

  11. A review of heterogeneous photocatalysis for water and surface disinfection.

    Science.gov (United States)

    Byrne, John Anthony; Dunlop, Patrick Stuart Morris; Hamilton, Jeremy William John; Fernández-Ibáñez, Pilar; Polo-López, Inmaculada; Sharma, Preetam Kumar; Vennard, Ashlene Sarah Margaret

    2015-03-30

    Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give "self-disinfecting" surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

  12. ASSESSMENT OF ACTION OF DISINFECTANTS AGAINST LISTERIA MONOCYTOGENES BIOFILMS

    Directory of Open Access Journals (Sweden)

    T. K. CABEÇA

    2008-12-01

    Full Text Available

    The purpose of this study was to assess the action of various disinfectants used in food industry against biofilm cells of Listeria monocytogenes formed on stainless steel surfaces during 24, 72 and 120 hours. Numbers of viable biofilm cells decreased after treatment with all the tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against the biofilm cells, while biguanide and iodine were the least. Scanning electron microscopy observations demonstrated attached cells on stainless steel surfaces after treatment with all the disinfectants. These observations showed that microorganisms were not completely removed from stainless steel surfaces after treatment with the disinfectants, however, the attachment did not means the viability of remaining cells. The biofilm age in hours (24, 72 and 120 had no apparent influence on resistance of microbiological cells to the disinfectants under study. In conclusion biofilm cells of L. monocytogenes can withstand disinfectants action.

  13. Solar disinfection improves drinking water quality to prevent diarrhea in under-five children in sikkim, India.

    Science.gov (United States)

    Rai, Bb; Pal, Ranabir; Kar, Sumit; Tsering, Dechen C

    2010-09-01

    Solar radiations improve the microbiological quality of water and offer a method for disinfection of drinking water that requires few resources and no expertise and may reduce the prevalence of diarrhea among under-five children. To find out the reduction in the prevalence of diarrhea in the under-five children after consumption of potable water treated with solar disinfection method. This was a population-based interventional prospective study in the urban slum area of Mazegoan, Jorethang, south Sikkim, during the period 1(st) May 2007 to 30(th) November 2007 on 136 children in the under-five age group in 102 households selected by random sampling. Main outcome measure was the assessment of the reduction of the prevalence of diarrhea among under-five children after consumption of potable water treated with solar disinfection method practiced by the caregivers in the intervention group keeping water in polyethylene terephthalate (PET) bottles as directed by the investigators. The data were collected by the interview method using a pre-tested questionnaire prepared on the basis of socio-demographics and prevalence of diarrhea. The data were subjected to percentages and chi-square tests, which were used to find the significance. After four weeks of intervention among the study group, the diarrhea prevalence was 7.69% among solar disinfection (SODIS) users, while 31.82% prevalence was observed among non-users in that period; the reduction in prevalence of diarrhea was 75.83%. After eight weeks of intervention, the prevalence of diarrhea was 7.58% among SODIS users and 31.43% among non-users; the reduction in diarrhea was 75.88% in the study group. The findings were found to be statistically significant. In our study, we observed that the prevalence of diarrhea decreased significantly after solar disinfection of water was practiced by the caregivers keeping potable water in PET bottles in the intervention group.

  14. Online dating and education

    Directory of Open Access Journals (Sweden)

    Yvonne Fritze

    2012-11-01

    Full Text Available Taking its inspiration from Luhmann's communication theory, this article looks at online dating from the perspective of teaching and education. While Eros obviously plays an important role in regenerating the desire to communicate, this ardour is often absent from the domain of net-based teaching. The article explores those features of online dating characteristic of distance dialogue, and discusses the extent to which these can be transferred to communication in the teaching context. We further argue that participation in online dating increases communicators' competence and self-reflection.

  15. Integration of an innovative biological treatment with physical or chemical disinfection for wastewater reuse

    Energy Technology Data Exchange (ETDEWEB)

    De Sanctis, Marco, E-mail: marco.desanctis@ba.irsa.cnr.it [Water Research Institute, CNR, Via F. De Blasio 5, 70123 Bari (Italy); Del Moro, Guido [Water Research Institute, CNR, Via F. De Blasio 5, 70123 Bari (Italy); Levantesi, Caterina; Luprano, Maria Laura [Water Research Institute, CNR, Via Salaria Km 29.600, 00015 Monterotondo, RM (Italy); Di Iaconi, Claudio [Water Research Institute, CNR, Via F. De Blasio 5, 70123 Bari (Italy)

    2016-02-01

    In the present paper, the effectiveness of a Sequencing Batch Biofilter Granular Reactor (SBBGR) and its integration with different disinfection strategies (UV irradiation, peracetic acid) for producing an effluent suitable for agricultural use was evaluated. The plant treated raw domestic sewage, and its performances were evaluated in terms of the removal efficiency of a wide group of physical, chemical and microbiological parameters. The SBBGR resulted really efficient in removing suspended solids, COD and nitrogen with an average effluent concentration of 5, 32 and 10 mg/L, respectively. Lower removal efficiency was observed for phosphorus with an average concentration in the effluent of 3 mg/L. Plant effluent was also characterized by an average electrical conductivity and sodium adsorption ratio of 680 μS/cm and 2.9, respectively. Therefore, according to these gross parameters, the SBBGR effluent was conformed to the national standards required in Italy for agricultural reuse. Moreover, disinfection performances of the SBBGR was higher than that of conventional municipal wastewater treatment plants and met the quality criteria suggested by WHO (Escherichia coli < 1000 CFU/100 mL) for agricultural reuse. In particular, the biological treatment by SBBGR removed 3.8 ± 0.4 log units of Giardia lamblia, 2.8 ± 0.8 log units of E. coli, 2.5 ± 0.7 log units of total coliforms, 2.0 ± 0.3 log units of Clostridium perfringens, 2.0 ± 0.4 log units of Cryptosporidium parvum and 1.7 ± 0.7 log units of Somatic coliphages. The investigated disinfection processes (UV and peracetic acid) resulted very effective for total coliforms, E. coli and somatic coliphages. In particular, a UV radiation and peracetic acid doses of 40 mJ/cm{sup 2} and 1 mg/L respectively reduced E. coli content in the effluent below the limit for agricultural reuse in Italy (10 CFU/100 mL). Conversely, they were both ineffective on C.perfringens spores. - Highlights: • SBBGR system showed high

  16. Evaluation of alternative methods for the disinfection of toothbrushes

    Directory of Open Access Journals (Sweden)

    Edson Yukio Komiyama

    2010-03-01

    Full Text Available The aim of this study was to evaluate alternative methods for the disinfection of toothbrushes considering that most of the previously proposed methods are expensive and cannot be easily implemented. Two-hundred toothbrushes with standardized dimensions and bristles were included in the study. The toothbrushes were divided into 20 experimental groups (n = 10, according to microorganism considered and chemical agent used. The toothbrushes were contaminated in vitro by standardized suspensions of Streptococcus mutans, Streptococcus pyogenes, Staphylococcus aureus or Candida albicans. The following disinfectants were tested: 0.12% chlorhexidine digluconate, 50% white vinegar, a triclosan-containing dentifrice solution, and a perborate-based tablet solution. The disinfection method was immersion in the disinfectant for 10 min. After the disinfection procedure, the number of remaining microbial cells was evaluated. The values of cfu/toothbrush of each group of microorganism after disinfection were compared by Kruskal-Wallis ANOVA and Dunn's test for multiple comparisons (5%. The chlorhexidine digluconate solution was the most effective disinfectant. The triclosan-based dentifrice solution promoted a significant reduction of all microorganisms' counts in relation to the control group. As to the disinfection with 50% vinegar, a significant reduction was observed for all the microorganisms, except for C. albicans. The sodium perborate solution was the less effective against the tested microorganisms. Solutions based on triclosan-containing dentifrice may be considered effective, nontoxic, cost-effective, and an easily applicable alternative for the disinfection of toothbrushes. The vinegar solution reduced the presence of S. aureus, S. mutans and S. pyogenes on toothbrushes.

  17. CONCERNS OF CONTEMPORARY DISINFECTION: CHLORINE OR STABILIZED LIQUID SOLUTION OF CHLORINE DIOXIDE

    OpenAIRE

    Abdulah Gagić; Selma Selimović; Suad Jukić; Ajla Ališah; Aida Kustura

    2014-01-01

    It is common that experts use routine procedures for disinfection. Every part of the disinfection procedure is routinely done: preparation of the disinfection media, selection of the type of disinfection, protective measures, effect control and environmental issues. This article offers a new insight into the use of stabilized liquid chlorine dioxide as a qualitative alternative disinfectant for wider application by comparing it to the most frequently used chlorine and its compounds. When used...

  18. NAIP 2014 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2014 National Agriculture Imagery Program (NAIP)...

  19. NAIP 2012 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2012 National Agriculture Imagery Program (NAIP)...

  20. Food Product Dating

    Science.gov (United States)

    ... Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices ... Web Content Viewer (JSR 286) Actions ${title} Loading... Food Product Dating "Best if Used By" is a ...

  1. NAIP 2011 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2011 National Agriculture Imagery Program (NAIP)...

  2. NAIP 2013 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2013 National Agriculture Imagery Program (NAIP)...

  3. Role of disinfection in the Infection Prevention Multibarrier System.

    Science.gov (United States)

    Kramer, Axel

    2007-09-13

    The role of disinfection in infection prevention has been analyzed over the past 50 years both in the form of benefit-risk evaluations as well as in an epidemiological sense. This has served as the basis for not only national and international guidelines and recommendations, but has also created the legal and normative framework for regulation of infection control (and hence of disinfection) in numerous and acts and ordinances. Likewise, today the efficacy of disinfection measures, user safety and environmental compatibility in line with the state of the art are assured. Compliance as regards the conductance of disinfection measures has increased accordingly. The user is able to select and correctly employ the disinfectant most suited to the intended disinfection procedure. The quality of the apparatus used has vastly improved since the coming into force of the German Medical Devices Act (MPG). And finally the preconditions for conductance of disinfection have become so matter of fact that it is easy to forget just what progress has been made here. This applies e.g. to the facilities now available for hand hygiene, for decontamination of instruments, laundry and bedpans with washer-disinfectors as well as for surface disinfection and drinking water disinfection. But it is the human being who continues to pose the greatest risk. Risk awareness does not always result in proper action being taken: it is hard to really grasp something that one cannot experience. As such, hand disinfection is often dispensed with, and without any sense of having done something wrong, the debate about the evidence of the usefulness of floor disinfection continues, and often medical practitioners fail to resort to exclusive automated decontamination of medical devices because of the costs incurred. Hospitals, nursing homes and rehabilitation establishments are obliged to set up a quality management system, and to continue developing this. This calls for a quality assurance system

  4. Disinfection of hospital blankets with synthetic phenolic compounds.

    Science.gov (United States)

    LARKIN, I M; BRIDSON, E Y; GRIEVE, W S; GIBSON, J W

    1961-01-01

    A cheap method by which hospital blankets may be effectively disinfected (approximately 3d. per blanket) is described. A recommendation is made that blankets from the patients' beds be divided into: ;socially dirty' blankets to be laundered, possibly at infrequent intervals; and ;socially clean' blankets to be disinfected frequently. The wide range of a synthetic phenolic compound is described. This substance is effective against all the common pathogenic bacteria in the presence of organic matter, anionic, or cationic detergents. Details are given of laboratory trials with this method of disinfection and of pilot trials at the Group hospital laundry. The recommended method is simpler and takes less time than ordinary washing.

  5. Online dating and education

    OpenAIRE

    Fritze, Yvonne; Nordkvelle, Yngve Troye

    2012-01-01

    Taking its inspiration from Luhmann’s communication theory, this article looks at online dating from the perspective of teaching and education. While Eros obviously plays an important role in regenerating the desire to communicate, this ardour is often absent from the domain of net-based teaching. The article explores those features of online dating characteristic of distance dialogue, and discusses the extent to which these can be transferred to communication in the teaching context. We furt...

  6. Antimicrobial-Coated Granules for Disinfecting Water

    Science.gov (United States)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

  7. Enhanced photocatalytic disinfection of indoor air

    Energy Technology Data Exchange (ETDEWEB)

    Vohra, Amit; Goswami, D.Y.; Deshpande, D.A.; Block, S.S. [Solar Energy and Energy Conversion Laboratory, Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2006-04-18

    A silver ion doped TiO{sub 2} based photocatalyst, with improved destruction of airborne microbes, has been developed. The performance of the silver ion doped photocatalyst is demonstrated using a catalyst coated filter in a recirculating air experimental facility. Bacillus cereus, Staphylococcus aureus, Escherichia coli, Aspergillus niger, and MS2 Bacteriophage have been used as indexes to demonstrate the high disinfection efficiency of the enhanced photocatalysis process. The microbial destruction performance of the enhanced photocatalyst is found to be an order of magnitude higher than that of a conventional TiO{sub 2} photocatalyst. The process of enhanced photocatalysis can thus be used effectively against high concentrations of airborne microorganisms, making it an attractive option as a defense against bio-terrorism. (author)

  8. Dating fossil opal phytoliths

    Energy Technology Data Exchange (ETDEWEB)

    Lentfer, C.; Boyd, B. [Southern Cross University, Lismore, NSW (Australia). School of Resource Science and Management; Torrence, R. [Australian Museum, Sydney, NSW (Australia). Division of Anthropology

    1999-11-01

    Full text: Opal phytoliths are microscopic silica bodies formed by the precipitation of hydrated silica dioxide (SiO{sub 2}nH{sub 2}0) in, around and between cell walls. They are relatively resistant to degradation in most environments and thus, can occur in large quantities in palaeosediments. Consequently, they are valuable tools for environmental reconstruction. Furthermore, phytoliths are often the only recoverable organic material in well oxidised sediments, the occluded carbon provides the opportunity for dating sediment whose ages have previously been difficult to determine, and thus, increase the potential for fine resolution determination of environmental change. This poster describes the results of an investigation assessing the viability of AMS radiocarbon dating of fossil phytolith inclusions using samples from Garua Island, West New Britain, PNG. Thirteen phytolith samples, isolated from sediments previously dated using tephrastratigraphy and C14 dating of macroremains of nutshells and wood charcoal, were used in the analysis. As a control measure, thirteen parallel samples of microscopic charcoal were also dated using AMS. The results show that the AMS dates for the microscopic charcoal samples are consistent with ages anticipated from the other dating methods, for all but one sample. However, the dates for eight of the thirteen phytolith samples are considerably younger than expected. This bias could be explained by several factors, including downwashing of phytolith through soils, bioturbation, carbon exchange through the siliceous matrix of the phytolith bodies, and contamination from extraneous sources of modern carbon retained in the samples. Research is currently focusing on the investigation of these issues and selected samples are in the process of being retreated with strong oxidising agents to clear contaminants prior to re-dating. Further to this, a full investigation of one profile with a long sequence is underway. High concentrations of

  9. Virucidal efficacy of hydrogen peroxide vapour disinfection.

    Science.gov (United States)

    Tuladhar, E; Terpstra, P; Koopmans, M; Duizer, E

    2012-02-01

    Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. To measure the virucidal efficacy of HPV against respiratory and enteric viruses on materials representing those found in institutions and homes. Poliovirus, human norovirus genogroup II.4 (GII.4), murine norovirus 1, rotavirus, adenovirus and influenza A (H1N1) virus dried on to stainless steel, framing panel and gauze carriers were exposed to HPV 127 ppm for 1h at room temperature in an isolator. Poliovirus was also exposed to HPV at different locations in a room. The virucidal effect was measured by comparing recoverable viral titres against unexposed controls. Polymerase chain reaction was used to evaluate the effect of HPV on viral genome reduction. HPV disinfection resulted in complete inactivation of all viruses tested, characterized by >4 log(10) reduction in infectious particles for poliovirus, rotavirus, adenovirus and murine norovirus on stainless steel and framing panel carriers, and >2 log(10) reduction for influenza A virus on stainless steel and framing panel carriers, and for all viruses on gauze carriers. Complete inactivation of poliovirus was demonstrated at several locations in the room. Reductions in viral genomes were minimal on framing panel and gauze carriers but significant on stainless steel carriers; human norovirus GII.4 genome was most resistant to HPV treatment. HPV could be an effective virucidal against enteric and respiratory viruses contaminating in-house environments. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  10. 76 FR 77831 - 2012 Presidential Candidate Matching Fund Submission Dates and Post Date of Ineligibility Dates...

    Science.gov (United States)

    2011-12-14

    ... 2012 Presidential Candidate Matching Fund Submission Dates and Post Date of Ineligibility Dates To...: Notice of matching fund submission dates and submission dates for statements of net outstanding campaign... fund submission dates for publicly funded 2012 presidential primary candidates. Eligible candidates may...

  11. Selecting a Sustainable Disinfection Technique for Wastewater Reuse Projects

    Directory of Open Access Journals (Sweden)

    Jorge Curiel-Esparza

    2014-09-01

    Full Text Available This paper presents an application of the Analytical Hierarchy Process (AHP by integrating a Delphi process for selecting the best sustainable disinfection technique for wastewater reuse projects. The proposed methodology provides project managers a tool to evaluate problems with multiple criteria and multiple alternatives which involve non-commeasurable decision criteria, with expert opinions playing a major role in the selection of these treatment technologies. Five disinfection techniques for wastewater reuse have been evaluated for each of the nine criteria weighted according to the opinions of consulted experts. Finally, the VIKOR method has been applied to determine a compromise solution, and to establish the stability of the results. Therefore, the expert system proposed to select the optimal disinfection alternative is a hybrid method combining the AHP with the Delphi method and the VIKOR technique, which is shown to be appropriate in realistic scenarios where multiple stakeholders are involved in the selection of a sustainable disinfection technique for wastewater reuse projects.

  12. Effects of wastewater disinfection on waterborne bacteria and viruses

    Science.gov (United States)

    Blatchley, E. R.; Gong, W.-L.; Alleman, J.E.; Rose, J.B.; Huffman, D.E.; Otaki, M.; Lisle, J.T.

    2007-01-01

    Wastewater disinfection is practiced with the goal of reducing risks of human exposure to pathogenic microorganisms. In most circumstances, the efficacy of a wastewater disinfection process is regulated and monitored based on measurements of the responses of indicator bacteria. However, inactivation of indicator bacteria does not guarantee an acceptable degree of inactivation among other waterborne microorganisms (e.g., microbial pathogens). Undisinfected effluent samples from several municipal wastewater treatment facilities were collected for analysis. Facilities were selected to provide a broad spectrum of effluent quality, particularly as related to nitrogenous compounds. Samples were subjected to bench-scale chlorination and dechlorination and UV irradiation under conditions that allowed compliance with relevant discharge regulations and such that disinfectant exposures could be accurately quantified. Disinfected samples were subjected to a battery of assays to assess the immediate and long-term effects of wastewater disinfection on waterborne bacteria and viruses. In general, (viable) bacterial populations showed an immediate decline as a result of disinfectant exposure; however, incubation of disinfected samples under conditions that were designed to mimic the conditions in a receiving stream resulted in substantial recovery of the total bacterial community. The bacterial groups that are commonly used as indicators do not provide an accurate representation of the response of the bacterial community to disinfectant exposure and subsequent recovery in the environment. UV irradiation and chlorination/dechlorination both accomplished measurable inactivation of indigenous phage; however, the extent of inactivation was fairly modest under the conditions of disinfection used in this study. UV irradiation was consistently more effective as a virucide than chlorination/dechlorination under the conditions of application, based on measurements of virus (phage

  13. Effects of different cavity‑disinfectants and potassium titanyl ...

    African Journals Online (AJOL)

    disinfectants and potassium titanyl phosphate (KTP) laser on microtensile bond strength to primary dentin. Chlorhexidine (CHX), propolis (PRO), ozonated water (OW), gaseous ozone (OG) and KTP laser were used for this purpose. Methodology: ...

  14. Waterline ATS B. globigii spore water disinfection data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Disinfection of B. globigii spores (a non-pathogenic surrogate for B. anthracis) in clean and dirty water using the ATS-Waterline system, which uses ultraviolet...

  15. Severe anaphylaxis to a new disinfectant: polyhexanide, a chlorhexidine polymer.

    Science.gov (United States)

    Olivieri, J; Eigenmann, P A; Hauser, C

    1998-10-03

    We describe the cases of an 18-year-old female and a 15-year-old male who developed severe anaphylaxis following contact of surgical wounds with the disinfectant Lavasept, containing polyhexanide, a polymerised form of chlorhexidine, during orthopaedic interventions. According to the manufacturer, this product is the only polyhexanide containing medical disinfectant, has recently been commercialised and is only available in Switzerland. One of the patients denied previous contact with this compound but both patients were previously exposed to chlorhexidine. Immediate-type hypersensitivity to polyhexanide was suggested by positive skin prick tests in the two patients and by negative skin tests in control individuals. Skin tests with chlorhexidine in the patients remained negative. We conclude that contact with the new disinfectant Lavasept can trigger anaphylactic reactions, even in the absence of previous history of exposure to this compound. It remains to be established whether this new disinfectant is a frequent anaphylactogen.

  16. Mimicking disinfection and drying of biofilms in contaminated endoscopes

    NARCIS (Netherlands)

    Kovaleva, J.; Degener, J. E.; van der Mei, H. C.

    2010-01-01

    The effects of peracetic acid-based (PAA) disinfectant with, and without, additional drying on Candida albicans, Candida parapsilosis, Pseudomonas aeruginosa and Stenotrophomonas maltophilia, isolated from contaminated flexible endoscopes, in single-and dual-species biofilms were studied. Biofilms

  17. The effectiveness of photocatalytic ionisation disinfection of filter materials.

    Science.gov (United States)

    Pietrzak, Katarzyna; Gutarowska, Beata

    2013-01-01

    The purpose of this study was to determine the effectiveness of photocatalytic ionisation as a disinfection method for filter materials contaminated by microorganisms, and to assess how air relative humidity (RH), time and microbe type influence the effectiveness of this disinfection. In the quantitative analysis of a used car air filter, bacterial contamination equalled 1.2 x 10(5) cfu/cm2, fungal contamination was 3.8 x 10(6) cfu/cm2, and the isolated microorganisms were Aspergillus niger, Bacillus megaterium, Cladosporium herbarum, Cryptococcus laurenti, Micrococcus sp., Rhodotorula glutinis and Staphylococcus cohnii. In the model experiment, three isolates (C. herbarum, R. glutinis, S. cohnii) and 3 ATCC species (A. niger, E. coli, S. aureus) were used for photocatalytic ionisation disinfection. The conditions of effective photocatalytic ionisation disinfection (R > or = 99.9%) were established as 2-3 h at RH = 77% (bacteria) and 6-24 h at RH = 53% (fungi). RH has an influence on the effectiveness of the photocatalytic disinfection process; the highest effectiveness was obtained for bacteria at RH = 77%, with results 5% higher than for RH = 49%. The studies show that the sensitivity of microorganisms to photocatalytic ionisation disinfection is ordered as follows: Gram-positive bacteria (S. cohnii, S. aureus), Gram-negative bacteria (E. coli), yeasts (R. glutinis), and moulds (C. herbarum, A. niger). Of all the mathematical models used for the description of death dynamics after photocatalytic ionisation disinfection, the Chick-Watson model is the most useful, but for more resistant microorganisms, the delayed Chick-Watson model is highly recommended. It therefore seems, that the presented disinfection method of photocatalytic ionisation can be successfully used to clean filtration materials.

  18. Effects of Disinfectants on Larval Development of Ascaris suum Eggs.

    Science.gov (United States)

    Oh, Ki-Seok; Kim, Geon-Tae; Ahn, Kyu-Sung; Shin, Sung-Shik

    2016-02-01

    The objective of this study was to evaluate the effects of several different commercial disinfectants on the embryogenic development of Ascaris suum eggs. A 1-ml aliquot of each disinfectant was mixed with approximately 40,000 decorticated or intact A. suum eggs in sterile tubes. After each treatment time (at 0.5, 1, 5, 10, 30, and 60 min), disinfectants were washed away, and egg suspensions were incubated at 25˚C in distilled water for development of larvae inside. At 3 weeks of incubation after exposure, ethanol, methanol, and chlorohexidin treatments did not affect the larval development of A. suum eggs, regardless of their concentration and treatment time. Among disinfectants tested in this study, 3% cresol, 0.2% sodium hypochlorite and 0.02% sodium hypochlorite delayed but not inactivated the embryonation of decorticated eggs at 3 weeks of incubation, because at 6 weeks of incubation, undeveloped eggs completed embryonation regardless of exposure time, except for 10% povidone iodine. When the albumin layer of A. suum eggs remained intact, however, even the 10% povidone iodine solution took at least 5 min to reasonably inactivate most eggs, but never completely kill them with even 60 min of exposure. This study demonstrated that the treatment of A. suum eggs with many commercially available disinfectants does not affect the embryonation. Although some disinfectants may delay or stop the embryonation of A. suum eggs, they can hardly kill them completely.

  19. Disinfection of Needleless Connector Hubs: Clinical Evidence Systematic Review

    Directory of Open Access Journals (Sweden)

    Nancy L. Moureau

    2015-01-01

    Full Text Available Background. Needleless connectors (NC are used on virtually all intravascular devices, providing an easy access point for infusion connection. Colonization of NC is considered the cause of 50% of postinsertion catheter-related infections. Breaks in aseptic technique, from failure to disinfect, result in contamination and subsequent biofilm formation within NC and catheters increasing the potential for infection of central and peripheral catheters. Methods. This systematic review evaluated 140 studies and 34 abstracts on NC disinfection practices, the impact of hub contamination on infection, and measures of education and compliance. Results. The greatest risk for contamination of the catheter after insertion is the NC with 33–45% contaminated, and compliance with disinfection as low as 10%. The optimal technique or disinfection time has not been identified, although scrubbing with 70% alcohol for 5–60 seconds is recommended. Studies have reported statistically significant results in infection reduction when passive alcohol disinfection caps are used (48–86% reduction. Clinical Implications. It is critical for healthcare facilities and clinicians to take responsibility for compliance with basic principles of asepsis compliance, to involve frontline staff in strategies, to facilitate education that promotes understanding of the consequences of failure, and to comply with the standard of care for hub disinfection.

  20. Disinfection of dental diamond burs contaminated with hepatitis B virus.

    Science.gov (United States)

    Leontiou, A P; Coogan, M M; Aspinall, S

    1999-09-01

    Hepatitis B infection (HBV) is a significant hazard in the dental environment because the virus may be transmitted through contaminated dental instruments. This study determined whether cold disinfectants can inactivate HBV DNA and HBV surface antigens on diamond burs contaminated with HBV and whether ultrasonication can increase the antiviral properties of these agents. Sterile dental diamond burs were contaminated with serum from a patient who tested positive for HBV surface antigen and hepatitis B viral DNA. The burs were air dried and placed in solutions containing either Cidex, Asepsys, TBS, Rotagerm, Virkon disinfectants, or a control phosphate buffered saline. Burs were divided into 2 groups and disinfected for 15 minutes. The first group was ultrasonicated; the second group was not ultrasonicated during disinfection. All the burs were transferred to phosphate buffered saline and ultrasonicated to remove any remaining viral particles. The ultrasonicate was tested for the presence of HBV surface antigen with a microparticle enzyme immunoassay and for hepatitis B viral DNA with a chemiluminescent molecular hybridization assay. TBS did not require ultrasonication to inactivate viral DNA and surface antigen. Rotagerm and Virkon inactivated surface antigen and viral DNA only with ultrasonication. Cidex and Asepsys inactivated viral DNA but not surface antigen with ultrasonication. The chlorine containing compound TBS was the most active disinfectant tested and did not require ultrasonication to destroy HBV. The remaining disinfectants should be used with ultrasonication to inactivate HBV.

  1. Nanosilver as a disinfectant in dental unit waterlines ...

    Science.gov (United States)

    Dental unit water lines (DUWL) are susceptible to biofilm development and bacterial growth leading to water contamination, causing health and ecological effects. This study monitors the interactions between a commonly used nanosilver disinfectant (ASAP-AGX-32, an antimicrobial cleaner for dental units, 0.0032% Ag) and biofilm development in DUWL. To simulate the disinfection scenario, an in-house DUWL model was assembled and biofilm accumulation was allowed. Subsequent to biofilm development, the disinfection process was performed according to the manufacturer's instructions. The pristine nanosilver particles in the cleaner measured between 3 and 5 nm in diameter and were surrounded by a stabilizing polymer. However, the polymeric stabilizing agent diminished over the disinfection process, initiating partial AgNPs aggregation. Furthermore, surface speciation of the pristine AgNPs were identified as primarily AgO, and after the disinfection process, transformations to AgCl were observed. The physicochemical characteristics of AgNPs are known to govern their fate, and transport and environmental implications. Hence, knowledge of the AgNPs characteristics after the disinfection process (usage scenario) is of significance. This study demonstrates the adsorption of AgNPs onto biofilm surfaces and, therefore, will assist in illustration of the toxicity mechanisms of AgNPs to bacteria and biofilms. This work can be an initial step in better understanding how

  2. A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection

    Directory of Open Access Journals (Sweden)

    John Anthony Byrne

    2015-03-01

    Full Text Available Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give “self-disinfecting” surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

  3. Stability and effectiveness of chlorine disinfectants in water distribution systems.

    Science.gov (United States)

    Olivieri, V P; Snead, M C; Krusé, C W; Kawata, K

    1986-11-01

    A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min.

  4. Effect of point‐of‐use disinfection, flocculation and combined flocculation–disinfection on drinking water quality in western Kenya

    National Research Council Canada - National Science Library

    Crump, J.A; Okoth, G.O; Slutsker, L; Ogaja, D.O; Keswick, B.H; Luby, S.P

    2004-01-01

    .... Methods and Results:  We evaluated a novel combined flocculant‐disinfectant point‐of‐use water treatment product and compared its effect on drinking water quality with existing technologies in western Kenya...

  5. Simple Continuous-Flow Device for Combined Solar Thermal Pasteurization and Solar Disinfection for Water Sterilization

    Directory of Open Access Journals (Sweden)

    Anthony Amsberry

    2015-02-01

    Full Text Available A collection unit and reflective concentrators were used to thermally preheat water to at least 70 °C for thermal pasteurization prior to a solar disinfection stage. The device is offered as a novel combined cycle to be used for either solar thermal pasteurization, during seasonalpeaks in solar irradiation, or as a solar preheat for UV solar disinfection which would occur in a flow-through solar disinfection trough. Inexpensive materials were used in order to simulate in field functionality and applicability to rural regions with low solar input. Solar incidence at Oregon State University, with latitude 45.5°, was recorded during trials conducted during May 1 to June 10 for the purpose of directly scaling the water treatment volumetric flowrate of the device for any future tests in other locations. This scaling by solar irradiation makes this dataset useful for other locations with higher or lower solar input and needing more or less treated water. The simple gravity-fed continuous system presented in this article makes use of a large cold water reservoir, a shell-and-tube heat exchanger, and a solar collector. The system, operating at flowrates of 100-150 mL/min is able to reach outlet temperatures of 74°C.  The system is projected to produce 55 L of purified water daily when operating on a sunny day with peak UV radiation above 700 W/m2. System cost was $55 with an added optional $15 for the shell-and-tube heat exchanger.

  6. Solar disinfection of drinking water and diarrhoea in Maasai children: a controlled field trial.

    Science.gov (United States)

    Conroy, R M; Elmore-Meegan, M; Joyce, T; McGuigan, K G; Barnes, J

    Solar radiation reduces the bacterial content of water, and may therefore offer a method for disinfection of drinking water that requires few resources and no expertise. We distributed plastic water bottles to 206 Maasai children aged 5-16 years whose drinking water was contaminated with faecal coliform bacteria. Children were instructed to fill the bottle with water and leave it in full sunlight on the roof of the hut (solar group), or to keep their filled bottles indoors in the shade (control group). A Maasai-speaking fieldworker who lived in the community interviewed the mother of each child once every 2 weeks for 12 weeks. Occurrence and severity of diarrhoea was recorded at each follow-up visit. Among the 108 children in households allocated solar treatment, diarrhoea was reported in 439 of the 2-week reporting periods during the 12-week trial (average 4.1 [SD 1.2] per child). By comparison, the 98 children in the control households reported diarrhoea during 444 2-week reporting periods (average 4.5 [1.2] per child). Diarrhoea severe enough to prevent performance of duties occurred during 186 reporting periods in the solar group and during 222 periods in the control group (average 1.7 [1.2] vs 2.3 [1.4]). After adjustment for age, solar treatment of drinking water was associated with a reduction in all diarrhoea episodes (odds ratio 0.66 [0.50-0.87]) and in episodes of severe diarrhoea (0.65 [0.50-0.86]). Our findings suggest that solar disinfection of water may significantly reduce morbidity in communities with no other means of disinfection of drinking water, because of lack of resources or in the event of a disaster.

  7. Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system.

    Directory of Open Access Journals (Sweden)

    Julianne L Baron

    Full Text Available Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.

  8. Iranian dates and ethnic date-based products

    OpenAIRE

    Vahid M. Karizaki

    2017-01-01

    Background: The origins of date production and use in Iran go back to about 4000 bc. Today, more than 400 types of date and various kinds of date-based foods are consumed by the Iranian people. This study aimed at documenting the information about date and date-based products in Iranian cuisine. Methods: The required data were determined by interviews with the farmers, domestic people, consumers, producers, and sellers of dates. In addition, online databases and scientific articles were sc...

  9. Biodiversity of date palm

    Science.gov (United States)

    The date palm (Phoenix dactylifera) is the dominant component upon which the sustainable biophysical and socio-economic structures of the oasis ecosystem are based; a fruit tree with unique nutritional, biochemical and biophysical characteristics, a rich source of aesthetic and cultural values, and ...

  10. Date palm: Production

    Science.gov (United States)

    The future of date palm, as a dioecious, monocot fruit tree largely depends on (1) developing advanced knowledge and information about the dynamics, management, and sustainability of the tree as a central component of the oasis agro-ecosystem, and (2) in-depth understanding of the genetic diversity ...

  11. Confronting Dating Violence.

    Science.gov (United States)

    McNulty, Raymond J.; Heller, Daniel A.; Binet, Tracy

    1997-01-01

    To be safe havens for children, schools cannot address the intellect only. Brattleboro (Vermont) Union High School went beyond academics by sponsoring a performance of "The Yellow Dress," a powerful one-woman play about a teenage victim of dating violence. The production challenged participants to unite school and community, intellect…

  12. Flirting in Online Dating

    DEFF Research Database (Denmark)

    Mortensen, Kristine Køhler

    2017-01-01

    Various fields have examined the activity of flirting, predominantly based on experimental and reported data; the interactional workings are therefore often overlooked. Based on emails and chats from two Danish online dating sites, this article investigates how users negotiate romantic connections...

  13. In vitro study on the disinfectability of two split-septum needle-free connection devices using different disinfection procedures

    Directory of Open Access Journals (Sweden)

    Engelhart, Steffen

    2015-12-01

    Full Text Available This in vitro study investigated the external disinfection of two needle-free connection devices (NFC using Octeniderm (spraying and wiping technique vs. Descoderm pads (wiping technique. The split-septum membrane of the NFC was contaminated with >10 CFU . The efficacy of the disinfection at 30 sec. exposure time was controlled by taking a swab sample and by flushing the NFC with sterile 0.9% sodium chloride solution. Disinfection with octenidine dihydrochloride 0.1 g, 1-Propanol 30.0 g, and 2-Propanol 45.0 g in solution was highly effective (CFU reduction ≥4 log against both microorganisms, whereas the use of 63.1 g 2-Propanol in 100 ml solution led to residual contamination with . Our investigation underlines that (i in clinical practice disinfection of NFCs before use is mandatory, and that (ii details of disinfection technique are of utmost importance regarding their efficacy. Our investigation revealed no significant differences between both split-septum NFC types. Clinical studies are needed to confirm a possible superiority of disinfectants with long-lasting residual antimicrobial activity.

  14. Organic chloramines in chlorine-based disinfected water systems: A critical review.

    Science.gov (United States)

    How, Zuo Tong; Kristiana, Ina; Busetti, Francesco; Linge, Kathryn L; Joll, Cynthia A

    2017-08-01

    This paper is a critical review of current knowledge of organic chloramines in water systems, including their formation, stability, toxicity, analytical methods for detection, and their impact on drinking water treatment and quality. The term organic chloramines may refer to any halogenated organic compounds measured as part of combined chlorine (the difference between the measured free and total chlorine concentrations), and may include N-chloramines, N-chloramino acids, N-chloraldimines and N-chloramides. Organic chloramines can form when dissolved organic nitrogen or dissolved organic carbon react with either free chlorine or inorganic chloramines. They are potentially harmful to humans and may exist as an intermediate for other disinfection by-products. However, little information is available on the formation or occurrence of organic chloramines in water due to a number of challenges. One of the biggest challenges for the identification and quantification of organic chloramines in water systems is the lack of appropriate analytical methods. In addition, many of the organic chloramines that form during disinfection are unstable, which results in difficulties in sampling and detection. To date research has focussed on the study of organic monochloramines. However, given that breakpoint chlorination is commonly undertaken in water treatment systems, the formation of organic dichloramines should also be considered. Organic chloramines can be formed from many different precursors and pathways. Therefore, studying the occurrence of their precursors in water systems would enable better prediction and management of their formation. Copyright © 2017. Published by Elsevier B.V.

  15. Constructed wetlands combined with UV disinfection systems for removal of enteric pathogens and wastewater contaminants.

    Science.gov (United States)

    Azaizeh, H; Linden, K G; Barstow, C; Kalbouneh, S; Tellawi, A; Albalawneh, A; Gerchman, Y

    2013-01-01

    Water shortage is an ongoing cardinal issue in the Middle East region. Wastewater reuse offers some remediation, but to-date many rural communities in the Palestinian Authority (PA) and in Jordan are not connected to centralized wastewater treatment plants (WWTPs), many of them are disposing of their wastewater using infiltration septic tanks. This highlights the need for a small, local, low cost WWTP that can directly benefit local communities, producing effluents suitable for unrestricted irrigation. Constructed wetlands (CWs) could offer a solution as they are relatively easy and cheap to construct and maintain, and effective in removal of many pollutants. Nevertheless, pathogen removal in CWs is often not adequate, calling for additional disinfection. Here we describe the use of low-cost, consumer level, UV based disinfection systems coupled to CWs for wastewater treatment in three CWs: in Israel, Jordan and in the PA. Once mature, our adapted CWs reduced chemical oxygen demand (COD) load, and, given proper use of the UV systems, inactivated indicator bacteria (faecal and E. coli) to levels suitable for irrigation, even when UV transmission (UVT) levels were low (∼40%). Our results demonstrate the promise in this combined treatment technique for cheap and simple wastewater treatment suitable for the Middle East region.

  16. Compact Nd:YAG laser operating at 1.06, 1.32, and 1.44 μm for dental caries effective disinfection

    Science.gov (United States)

    Dostálová, Tat'jana; Jelínková, Helena; Kadlecová, Martina; Němec, Michal; Å ulc, Jan; Fibrich, Martin; Nejezchleb, Karel; Kapitch, Nickalai; Å koda, Václav

    2017-02-01

    The analysis of the disinfection effect of Nd:YAG laser radiation was investigated for patients with high concentration of Streptococcus mutans in saliva (positive result in Saliva-check mutans test). For the interaction the Nd:YAG laser system generated separate switchable wavelengths with the maximum output energies 1.1, 0.6, and 0.3 J for wavelength 1.06 μm, 1.32, μm and 1.44 μm, respectively, was used. Our study proved that after the laser irradiation the Saliva-check test showed negative presence of Streptococcus mutans. The disinfection effect was confirmed for all used radiation wavelength. For 1.44 μm this effect was reached with a smallest energy density.

  17. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell.

    Science.gov (United States)

    Huang, Xiao; Qu, Yan; Cid, Clément A; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C

    2016-04-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Recent findings in pulsed light disinfection.

    Science.gov (United States)

    Kramer, B; Wunderlich, J; Muranyi, P

    2017-04-01

    Nonthermal disinfection technologies are gaining increasing interest in the field of minimally processed food in order to improve the microbial safety or to extend the shelf life. Especially fresh-cut produce or meat and fish products are vulnerable to microbial spoilage, but, due to their sensitivity, they require gentle preservation measures. The application of intense light pulses of a broad spectral range comprising ultraviolet, visible and near infrared irradiation is currently investigated as a potentially suitable technology to reduce microbial loads on different food surfaces or in beverages. Considerable research has been performed within the last two decades, in which the impact of various process parameters or microbial responses as well as the suitability of pulsed light (PL) for food applications has been examined. This review summarizes the outcome of the latest studies dealing with the treatment of various foods including the impact of PL on food properties as well as recent findings about the microbicidal action and relevant process parameters. © 2016 The Society for Applied Microbiology.

  19. Dating fractures in infants

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, K.E., E-mail: kath.halliday@nuh.nhs.uk [Department of Radiology, Nottingham University Hospitals, Queen' s Medical Centre, Nottingham (United Kingdom); Broderick, N.J.; Somers, J.M. [Department of Radiology, Nottingham University Hospitals, Queen' s Medical Centre, Nottingham (United Kingdom); Hawkes, R. [Department of Radiology, Paul O' Gorman Building, Bristol (United Kingdom)

    2011-11-15

    Aim: To document the timing of the appearance of the radiological features of fracture healing in a group of infants in which the date of injury was known and to assess the degree of interobserver agreement. Materials and methods: Three paediatric radiologists independently assessed 161 images of 37 long bone fractures in 31 patients aged 0-44 months. The following features were assessed: soft-tissue swelling, subperiosteal new bone formation (SPNBF), definition of fracture line, presence or absence of callus, whether callus was well or ill defined, and the presence of endosteal callus. Results: Agreement between observers was only moderate for all discriminators except SPNBF. SPNBF was invariably seen after 11 days but was uncommon before this time even in the very young. In one case SPNBF was seen at 4 days. Conclusion: With the exception of SPNBF, the criteria relied on to date fractures are either not reproducible or are poor discriminators of fracture age.

  20. Overcoming the problem of residual microbial contamination in dental suction units left by conventional disinfection using novel single component suction handpieces in combination with automated flood disinfection.

    Science.gov (United States)

    Boyle, M A; O'Donnell, M J; Russell, R J; Galvin, N; Swan, J; Coleman, D C

    2015-10-01

    Decontaminating dental chair unit (DCU) suction systems in a convenient, safe and effective manner is problematic. This study aimed to identify and quantify the extent of the problems using 25 DCUs, methodically eliminate these problems and develop an efficient approach for reliable, effective, automated disinfection. DCU suction system residual contamination by environmental and human-derived bacteria was evaluated by microbiological culture following standard aspiration disinfection with a quaternary ammonium disinfectant or alternatively, a novel flooding approach to disinfection. Disinfection of multicomponent suction handpieces, assembled and disassembled, was also studied. A prototype manual and a novel automated Suction Tube Cleaning System (STCS) were developed and tested, as were novel single component suction handpieces. Standard aspiration disinfection consistently failed to decontaminate DCU suction systems effectively. Semi-confluent bacterial growth (101-500 colony forming units (CFU) per culture plate) was recovered from up to 60% of suction filter housings and from up to 19% of high and 37% of low volume suction hoses. Manual and automated flood disinfection of DCU suction systems reduced this dramatically (ranges for filter cage and high and low volume hoses of 0-22, 0-16 and 0-14CFU/plate, respectively) (Psuction handpieces could not be adequately disinfected without prior removal and disassembly. Novel single component handpieces, allowed their effective disinfection in situ using the STCS, which virtually eliminated contamination from the entire suction system. Flood disinfection of DCU suction systems and single component handpieces radically improves disinfection efficacy and considerably reduces potential cross-infection and cross-contamination risks. DCU suction systems become heavily contaminated during use. Conventional disinfection does not adequately control this. Furthermore, multicomponent suction handpieces cannot be adequately

  1. Differences in disinfection protocols for root canal treatments between general dentists and endodontists: A Web-based survey.

    Science.gov (United States)

    de Gregorio, Cesar; Arias, Ana; Navarrete, Natalia; Cisneros, Rafael; Cohenca, Nestor

    2015-07-01

    The purpose of this study was to determine whether differences exist in disinfection protocols between endodontists and general dentists. The authors sent an invitation to participate in a Web-based survey to 950 dentists affiliated with the Spanish Board of Dentistry. Participants responded to 9 questions about irrigation protocols and other factors related to disinfection during root canal therapy. A total of 238 (25.05%) study participants successfully completed and returned the surveys. Among these participants, 50% were general dentists and 50% were endodontists. The authors found no statistically significant differences in respondents' first choice of an irrigant solution (that is, sodium hypochlorite), but they noted statistically significant differences in the protocols used by general dentists and by endodontists in relation to the concentration of sodium hypochlorite (P = .0003), the use and type of irrigant used to remove the smear layer (P = 5.39 × 10(-10)), the use of adjuncts to irrigation (P = 5.98 × 10(-8)), the enlargement of the apical preparation when shaping a necrotic tooth (P = .001), and the maintenance of apical patency throughout the debridement and shaping procedure (P = .04). General dentists and endodontists embrace different disinfection protocols. The results of the survey demonstrated that endodontists keep up to date with protocols published in the literature, whereas general dentists use protocols learned during their dental training. Both groups of clinicians should be aware of the importance of disinfection techniques and their relationship to treatment outcomes. Controlling microorganisms during a root canal treatment, especially in cases with necrotic pulp, is essential to improve treatment outcomes. Clinicians should update their protocols and also consider referring patients to a specialist when their protocols are based on traditional techniques, especially in those cases with necrotic pulp. Copyright © 2015

  2. Using Limes and Synthetic Psoralens to Enhance Solar Disinfection of Water (SODIS): A Laboratory Evaluation with Norovirus, Escherichia coli, and MS2

    OpenAIRE

    Harding, Alexander S.; Schwab, Kellogg J.

    2012-01-01

    We investigated the use of psoralens and limes to enhance solar disinfection of water (SODIS) using an UV lamp and natural sunlight experiments. SODIS conditions were replicated using sunlight, 2 L polyethylene terephthalate (PET) bottles, and tap water with Escherichia coli, MS2 bacteriophage, and murine norovirus (MNV). Psoralens and lime acidity both interact synergistically with UV radiation to accelerate inactivation of microbes. Escherichia coli was ablated > 6.1 logs by SODIS + Lime Sl...

  3. Integrated Disinfection By-Products Mixtures Research: Concentration by Reverse Osmosis Membrane Techniques of Disinfection By-Products from Water Disinfected by Chlorination and Ozonation/Postchlorination

    Science.gov (United States)

    To conduct the health-effect studies described in subsequent articles in this series, concentrated aqueous mixtures of disinfection by-products were required for the two water treatment trains described in the preceding article (Miltner et al., 2008). To accomplish this, the fini...

  4. Clinical and cost effectiveness of eight disinfection methods for terminal disinfection of hospital isolation rooms contaminated with Clostridium difficile 027.

    Science.gov (United States)

    Doan, L; Forrest, H; Fakis, A; Craig, J; Claxton, L; Khare, M

    2012-10-01

    Clostridium difficile spores can survive in the environment for months or years, and contaminated environmental surfaces are important sources of nosocomial C. difficile transmission. To compare the clinical and cost effectiveness of eight C. difficile environmental disinfection methods for the terminal cleaning of hospital rooms contaminated with C. difficile spores. This was a novel randomized prospective study undertaken in three phases. Each empty hospital room was disinfected, then contaminated with C. difficile spores and disinfected with one of eight disinfection products: hydrogen peroxide vapour (HPV; Bioquell Q10) 350-700 parts per million (ppm); dry ozone at 25 ppm (Meditrox); 1000 ppm chlorine-releasing agent (Actichlor Plus); microfibre cloths (Vermop) used in combination with and without a chlorine-releasing agent; high temperature over heated dry atomized steam cleaning (Polti steam) in combination with a sanitizing solution (HPMed); steam cleaning (Osprey steam); and peracetic acid wipes (Clinell). Swabs were inoculated on to C. difficile-selective agar and colony counts were performed pre and post disinfection for each method. A cost-effectiveness analysis was also undertaken comparing all methods to the current method of 1000 ppm chlorine-releasing agent (Actichlor Plus). Products were ranked according to the log(10) reduction in colony count from contamination phase to disinfection. The three statistically significant most effective products were hydrogen peroxide (2.303); 1000 ppm chlorine-releasing agent (2.223) and peracetic acid wipes (2.134). The cheaper traditional method of using a chlorine-releasing agent for disinfection was as effective as modern methods. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  5. Kennel Disinfectants for Microsporum canis and Trichophyton sp.

    Directory of Open Access Journals (Sweden)

    Karen A. Moriello

    2015-01-01

    Full Text Available The antifungal efficacy of commonly used kennel disinfectants for large surfaces was tested using naturally infective material from untreated animals (M. canis and Trichophyton sp. soaked and macerated but unfiltered leaving visible fluorescing hairs and/or scales in the test inoculum to create a robust challenge. Disinfectants included sodium hypochlorite (1 : 32 and 1 : 100, enilconazole (1 : 100, accelerated hydrogen peroxide (1 : 16, potassium peroxymonosulfate (1% and 2%, and calcium hypochlorite “dry bleach.” Disinfectants were tested at a 1 : 10, 1 : 5, and 1 : 1 dilution of test inoculum to disinfectant with a 10 min contact time. Good efficacy was defined as a disinfectant resulting in no growth. Control plates grew >300 colonies of each pathogen per plate. Enilconazole, sodium hypochlorite (all dilutions, accelerated hydrogen peroxide, and 2% potassium peroxymonosulfate (but not 1% inhibited all growth of both pathogens at 1 : 10, 1 : 5, and 1 : 1 dilutions. Calcium hypochlorite showed no antifungal efficacy (>300 colonies per plate. Enilconazole (1 : 100, sodium hypochlorite (1 : 32 or 1 : 100, accelerated hydrogen peroxide (1 : 16, and 2% potassium peroxymonosulfate are recommended for decontamination of kennels exposed to dermatophyte pathogens.

  6. Kennel Disinfectants for Microsporum canis and Trichophyton sp.

    Science.gov (United States)

    Moriello, Karen A

    2015-01-01

    The antifungal efficacy of commonly used kennel disinfectants for large surfaces was tested using naturally infective material from untreated animals (M. canis and Trichophyton sp.) soaked and macerated but unfiltered leaving visible fluorescing hairs and/or scales in the test inoculum to create a robust challenge. Disinfectants included sodium hypochlorite (1 : 32 and 1 : 100), enilconazole (1 : 100), accelerated hydrogen peroxide (1 : 16), potassium peroxymonosulfate (1% and 2%), and calcium hypochlorite "dry bleach." Disinfectants were tested at a 1 : 10, 1 : 5, and 1 : 1 dilution of test inoculum to disinfectant with a 10 min contact time. Good efficacy was defined as a disinfectant resulting in no growth. Control plates grew >300 colonies of each pathogen per plate. Enilconazole, sodium hypochlorite (all dilutions), accelerated hydrogen peroxide, and 2% potassium peroxymonosulfate (but not 1%) inhibited all growth of both pathogens at 1 : 10, 1 : 5, and 1 : 1 dilutions. Calcium hypochlorite showed no antifungal efficacy (>300 colonies per plate). Enilconazole (1 : 100), sodium hypochlorite (1 : 32 or 1 : 100), accelerated hydrogen peroxide (1 : 16), and 2% potassium peroxymonosulfate are recommended for decontamination of kennels exposed to dermatophyte pathogens.

  7. Analysis of fungal contamination and disinfection of toothbrushes.

    Science.gov (United States)

    Mobin, Mitra; Borba, Cíntia De M; Filho, Carlos A M; Tapety, Fabrício I; Noleto, Iraci De M S; Teles, João B M

    2011-01-01

    The aim of this study is to determine the fungal species in the toothbrushes of residents of a neighborhood on the east side of Teresina - PI, and to assess the efficiency of a disinfection method based on 2% sodium hypochlorite. Fifty toothbrushes were divided into two groups: group A comprised 30 toothbrushes used by the residents and group B (control group) 20 new toothbrushes. Fungal evaluation was conducted in Sabouraud culture medium containing chloramphenicol and CHROMagar Candida. Later group A was divided into two subgroups (A1 and A2), which were submitted to disinfection by immersion in 2% sodium hypochlorite and once again screened for the presence of fungi. Seventeen fungal species were identified in group A before the disinfection. Fungal growth was not observed in subgroups A1 and A2, or group B after disinfection. All fungal species isolated from the toothbrushes were considered opportunistic and may cause health problems mainly in immunocompromised patients. The species most frequently found were: Candida albicans, Aspergillus niger, Penicillium citrinum, Geotrichum candidum, Aspergillus fumigatus and Cladosporium oxysporum. Fungal growth did not occur after toothbrush disinfection with 2% sodium hypochlorite, suggesting this is an efficient, low-cost method that can therefore be used by low income populations.

  8. Effectiveness of Four Disinfectants against Ebola Virus on Different Materials

    Directory of Open Access Journals (Sweden)

    Sophie Smither

    2016-07-01

    Full Text Available The West Africa Ebola virus (EBOV outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus.

  9. Evaluation of in vitro efficacy of the disinfectant Virkon.

    Science.gov (United States)

    Gasparini, R; Pozzi, T; Magnelli, R; Fatighenti, D; Giotti, E; Poliseno, G; Pratelli, M; Severini, R; Bonanni, P; De Feo, L

    1995-04-01

    A study was conducted on a new acid peroxygen system based disinfectant (Virkon), in order to assess its in vitro efficacy. The chemical was tested on different bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli), spores (Bacillus subtilis) and on the Hepatitis B surface antigen (HBsAg), and compared in its activity with phenol and glutaraldehyde (calculation of the 'phenol coefficient' and the 'glutaraldehyde coefficient'). The constancy of speed of disinfection, the coefficient of concentration, the minimal inhibitory concentration (MIC) were also determined, and the destruction of the HBsAg antigenic activity was studied using an ELISA kit. The sporicidal efficacy of Virkon was assessed by cultivating spores in agar nutrient after contact with different dilutions of the disinfectant. The results of the tests showed that Virkon has a high concentration coefficient (mean value of k: 0.374/min) and a wide range of action. The low MIC demonstrates how little concentrations of Virkon can inactivate all studied bacteria. The disinfectant was also able to destroy the hepatitis B surface antigen, and it demonstrated good activity against spores, especially if used in physiologic solution. These characteristics, coupled with the absence of initiation or toxic effects on animals showed by other studies, make wide fields of application for the new disinfectant foreseeable.

  10. Disinfection by-product formation during seawater desalination: A review.

    Science.gov (United States)

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Assessment of disinfection of hospital surfaces using different monitoring methods

    Directory of Open Access Journals (Sweden)

    Adriano Menis Ferreira

    2015-06-01

    Full Text Available OBJECTIVE: to assess the efficiency of cleaning/disinfection of surfaces of an Intensive Care Unit.METHOD: descriptive-exploratory study with quantitative approach conducted over the course of four weeks. Visual inspection, bioluminescence adenosine triphosphate and microbiological indicators were used to indicate cleanliness/disinfection. Five surfaces (bed rails, bedside tables, infusion pumps, nurses' counter, and medical prescription table were assessed before and after the use of rubbing alcohol at 70% (w/v, totaling 160 samples for each method. Non-parametric tests were used considering statistically significant differences at p<0.05.RESULTS: after the cleaning/disinfection process, 87.5, 79.4 and 87.5% of the surfaces were considered clean using the visual inspection, bioluminescence adenosine triphosphate and microbiological analyses, respectively. A statistically significant decrease was observed in the disapproval rates after the cleaning process considering the three assessment methods; the visual inspection was the least reliable.CONCLUSION: the cleaning/disinfection method was efficient in reducing microbial load and organic matter of surfaces, however, these findings require further study to clarify aspects related to the efficiency of friction, its frequency, and whether or not there is association with other inputs to achieve improved results of the cleaning/disinfection process.

  12. Development of an Ultrasonic Resonator for Ballast Water Disinfection

    Science.gov (United States)

    Osman, Hafiiz; Lim, Fannon; Lucas, Margaret; Balasubramaniam, Prakash

    Ultrasonic disinfection involves the application of low-frequency acoustic energy in a water body to induce cavitation. The implosion of cavitation bubbles generates high speed microjets >1 km/s, intense shock wave >1 GPa, localized hot spots >1000 K, and free-radicals, resulting in cell rupture and death of micro-organisms and pathogens. Treatment of marine ballast water using power ultrasonics is an energy-intensive process. Compared with other physical treatment methods such as ultraviolet disinfection, ultrasonic disinfection require 2 to 3 orders of magnitude more energy to achieve similar rate of micro-organism mortality. Current technology limits the amount of acoustic energy that can be transferred per unit volume of fluid and presents challenges when it comes to high-flow applications. Significant advancements in ultrasonic processing technology are needed before ultrasound can be recognized as a viable alternative disinfection method. The ultrasonic resonator has been identified as one of the areas of improvement that can potentially contribute to the overall performance of an ultrasonic disinfection system. The present study focuses on the design of multiple-orifice resonators (MOR) for generating a well-distributed cavitation field. Results show that the MOR resonator offers significantly larger vibrational surface area to mass ratio. In addition, acoustic pressure measurements indicate that the MOR resonators are able to distribute the acoustic energy across a larger surface area, while generating 2-4 times higher pressures than existing ultrasonic probes.

  13. Effect of disinfectant solutions on a denture base acrylic resin.

    Science.gov (United States)

    Carvalho, Cristiane F; Vanderlei, Aleska D; Marocho, Susana M Salazar; Pereira, Sarina M B; Nogueira, Lafayette; Paes-Júnior, Tarcisio J Arruda

    2012-01-01

    The aim of this study was to evaluate the hardness, roughness and mass loss of an acrylic denture base resin after in vitro exposure to four disinfectant solutions. Forty specimens (Clássico, Brazil) were prepared and randomly assigned to 4 groups n = 10) according to the disinfectant solution: G1: control, stored in distilled water at 37 degrees C; G2: 1% sodium hypochlorite; G3: 2% glutaraldehyde; G4: 4% chlorhexidine. G2 to G4 were immersed for 60 minutes in the disinfectant solution. Measurements were carried out both before and after immersion in the solution. The surface was analyzed with a surface roughness tester (Surfcorder SE 1700 KOZAKALAB), a microdurometer FM-700 (Future Tech) and a scanning electron microscope (DSM 962-ZEISS). Loss of mass was determined with a digital weighing scale. After disinfection procedures, values were analyzed statistically. The acrylic denture base resin may be vulnerable to surface changes after in vitro immersion in the disinfectant solutions studied.

  14. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE DISINFECTION BY-PRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfection by-products (DBPs) at a pilot plant in Evansville, Indiana, that uses chlorine dioxide as a primary disinfectant. nconventional multispectral identification techniques (gas chromatography combined with high and low r...

  15. Residual viral and bacterial contamination of surfaces after cleaning and disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Beumer, R.R.; Duizer, E.

    2012-01-01

    Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses,

  16. 40 CFR 141.708 - Requirements when making a significant change in disinfection practice.

    Science.gov (United States)

    2010-07-01

    ... calculate disinfection benchmarks for Giardia lamblia and viruses as described in § 141.709. Prior to... disinfection benchmark for Giardia lamblia and viruses as described in § 141.709. (2) A description of the...

  17. QUENCHING OF CHLORINATION DISINFECTION BY-PRODUCT FORMATION IN DRINKING WATER BY HYDROGEN PEROXIDE. (R825362)

    Science.gov (United States)

    Reactions between chlorine disinfectants, dissolved organic matter, and other chemicals in water form a series of disinfection by-products (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs), that are toxic and subject to increasingly stringent regulations. Th...

  18. Disinfection of stabilization pond effluent by peracetic acid and sodium hypochlorite

    Directory of Open Access Journals (Sweden)

    Negar Rezania

    2013-01-01

    Conclusions: The study demonstrated that application of combined PAA and NaOCl in disinfecting the effluent of the stabilization pond will promote the efficiency of disinfection process in inactivating the coliform group bacteria and fecal streptococci.

  19. [The posibility of usage microwave energy as an alternative method of disinfection for silicone impressions in orthopaedic dentistry].

    Science.gov (United States)

    Nespriad'ko, V P; Shevchuk, V O; Omel'ianenko, M D

    2011-01-01

    In this experimental investigation estimated the effect of microwave disinfection on the alteration of dimensional stability of silicone impressions and gypsum casts poured from them comparing to an invariable parameters of metal die. In this article uncovers the main point of origin, spreading and influence according to the classical theory of electro-magnetic waves (EMW) as an example was used the model M745R Samsung microwave oven. We evaluated possibilities and advantages of use the auxiliary plant for flowing regulation of the power of microwave radiation that calls "microUndaDent". It was designed, developed and installated by us in the department of orthopaedic dentistry.

  20. Dating Violence among College Students

    Science.gov (United States)

    Iconis, Rosemary

    2013-01-01

    Dating violence is a significant problem on college campuses. More than one-fifth of the undergraduate dating population are physically abused by their dating partners and an even greater percentage are psychologically abused. Researchers have identified risk factors for college student dating violence. Preventive interventions are strongly…

  1. Conventional and Alternative Disinfection Methods of Legionella in Water Distribution Systems – Review

    Directory of Open Access Journals (Sweden)

    Pūle Daina

    2016-12-01

    Full Text Available Prevalence of Legionella in drinking water distribution systems is a widespread problem. Outbreaks of Legionella caused diseases occur despite various disinfectants are used in order to control Legionella. Conventional methods like thermal disinfection, silver/copper ionization, ultraviolet irradiation or chlorine-based disinfection have not been effective in the long term for control of biofilm bacteria. Therefore, research to develop more effective disinfection methods is still necessary.

  2. Two-step chlorination: a new approach to disinfection of a primary sewage effluent

    OpenAIRE

    Li, Y.; Yang, M; Zhang, X; Jiang, J.; Liu, J.; Yau, CF; Graham, NJ; Li, X.

    2016-01-01

    Sewage disinfection aims at inactivating pathogenic microorganisms and preventing the transmission of waterborne diseases. Chlorination is extensively applied for disinfecting sewage effluents. The objective of achieving a disinfection goal and reducing disinfectant consumption and operational costs remains a challenge in sewage treatment. In this study, we have demonstrated that, for the same chlorine dosage, a two-step addition of chlorine (two-step chlorination) was significantly more effi...

  3. Three-step effluent chlorination increases disinfection efficiency and reduces DBP formation and toxicity.

    OpenAIRE

    Li, Y; Zhang, X.; Yang, M; Liu, J.; Li, W; Graham, NJ; Li, X.; Yang, B.

    2016-01-01

    Chlorination is extensively applied for disinfecting sewage effluents, but it unintentionally generates disinfection byproducts (DBPs). Using seawater for toilet flushing introduces a high level of bromide into domestic sewage. Chlorination of sewage effluent rich in bromide causes the formation of brominated DBPs. The objectives of achieving a disinfection goal, reducing disinfectant consumption and operational costs, as well as diminishing adverse effects to aquatic organisms in receiving w...

  4. Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region.

    Science.gov (United States)

    Ndounla, J; Pulgarin, C

    2014-09-15

    The photo-disinfection of water from two different wells (W1, pH: 4.6-5.1 ± 0.02) and (W2 pH: 5.6-5.7 ± 0.02) was carried out during the rainy season at Ouagadougou-Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO3(-) concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO3(-) concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and ammonia. Copyright © 2014 Elsevier B

  5. Topics in radiation dosimetry radiation dosimetry

    CERN Document Server

    1972-01-01

    Radiation Dosimetry, Supplement 1: Topics in Radiation Dosimetry covers instruments and techniques in dealing with special dosimetry problems. The book discusses thermoluminescence dosimetry in archeological dating; dosimetric applications of track etching; vacuum chambers of radiation measurement. The text also describes wall-less detectors in microdosimetry; dosimetry of low-energy X-rays; and the theory and general applicability of the gamma-ray theory of track effects to various systems. Dose equivalent determinations in neutron fields by means of moderator techniques; as well as developm

  6. 210Pb dating

    Science.gov (United States)

    Swarzenski, Peter W.

    2014-01-01

    Roughly fifty years ago, a small group of scientists from Belgium and the United States, trying to better constrain ice sheet accumulation rates, attempted to apply what was then know about environmental lead as a potential geochronometer. Thus Goldberg (1963) developed the first principles of the 210Pb dating method, which was soon followed by a paper by Crozaz et al. (1964), who examined accumulation history of Antarctic snow using 210Pb. Shortly thereafter, Koide et al. (1972, 1973) adapted this technique to unravel sediment deposition and accumulation records in deep-sea environments. Serendipitously, they chose to work in a deep basin off California, where an independent and robust age model had already been developed. Krishanswami et al. (1971) extended the use of this technique to lacustrine deposits to reconstruct depositional histories of lake sediment, and maybe more importantly, contaminant inputs and burial. Thus, the powerful tool for dating recent (up to about one century old) sediment deposits was established and soon widely adopted. Today almost all oceanographic or limnologic studies that address recent depositional reconstructions employ 210Pb as one of several possible geochronometers (Andrews et al., 2009; Gale, 2009; Baskaran, 2011; Persson and Helms, 2011). This paper presents a short overview of the principles of 210Pb dating and provides a few examples that illustrate the utility of this tracer in contrasting depositional systems. Potential caveats and uncertainties (Appleby et al., 1986; Binford, 1990; Binford et al., 1993; Smith, 2001; Hancock et al., 2002) inherent to the use and interpretation of 210Pb-derived age-models are also introduced. Recommendations as to best practices for most reliable uses and reporting are presented in the summary.

  7. Vulcanism and Radiocarbon Dates

    Science.gov (United States)

    Libby, L. M.; Libby, W. F.

    1972-10-01

    We consider whether the long term perturbation of radiocarbon dates, which is known to be approximately a sin function of period about 8000 years and amplitude of about 8% peak-to-peak, could have been caused in any major part by vulcanism. We conclude that this is not the case. On the contrary, present day volcanoes are a far less important source of inert CO{sub 2} (about 100 fold less) than is man's burning of fossil fuels which has caused the Suess dilution of about 2%. (auth)

  8. Thermal contribution to the inactivation of Cryptosporidium in plastic bottles during solar water disinfection procedures.

    Science.gov (United States)

    Gómez-Couso, Hipólito; Fontán-Sainz, María; Ares-Mazás, Elvira

    2010-01-01

    To determine the thermal contribution, independent of ultraviolet radiation, on the inactivation of Cryptosporidium parvum during solar water disinfection procedures (SODIS), oocysts were exposed for 4, 8, and 12 hours to temperatures recorded in polyethylene terephthalate bottles in previous SODIS studies carried out under field conditions. Inclusion/exclusion of the fluorogenic vital dye propidium iodide, spontaneous excystation, and infectivity studies were used to determine the inactivation of oocysts. There was a significant increase in the percentage of oocysts that took up propidium iodide and in the number of oocysts that excysted spontaneously. There was also a significant decrease in the intensity of infection elicited in suckling mice at the end of all exposure times. The results of the study demonstrate the importance of temperature in the inactivation of C. parvum oocysts during application of SODIS under natural conditions.

  9. Kinetics of carotenoid distribution in human skin in vivo after exogenous stress: disinfectant and wIRA-induced carotenoid depletion recovers from outside to inside

    Science.gov (United States)

    Fluhr, Joachim W.; Caspers, Peter; van der Pol, J. Andre; Richter, Heike; Sterry, Wolfram; Lademann, Juergen; Darvin, Maxim E.

    2011-03-01

    The human organism has developed a protection system against the destructive effect of free radicals. The aim of the present study was to investigate the extent of exogenous stress factors such as disinfectant and IR-A radiation on the skin, and their influence on the kinetics of carotenoids distribution during the recovery process. Ten healthy volunteers were assessed with resonance spectroscopy using an Argon-laser at 488 nm to excite the carotenoids in vivo. Additionally, Raman-confocal-micro-spectroscopy measurements were performed using a model 3510 Skin Composition Analyzer with spatially resolved measurements down to 30 μm. The measurements were performed at a baseline of 20, 40, 60, and 120 min after an external stressor consisting either of water-filtered infrared A (wIRA) with 150 mW/cm2 or 1 ml/cm2 of an alcoholic disinfectant. Both Raman methods were capable to detect the infrared-induced depletion of carotenoids. Only Raman-microspectroscopy could reveal the carotenoids decrease after topical disinfectant application. The carotenoid-depletion started at the surface. After 60 min, recovery starts at the surface while deeper parts were still depleted. The disinfectant- and wIRA-induced carotenoid depletion in the epidermis recovers from outside to inside and probably delivered by sweat and sebaceous glands. We could show that the Raman microscopic spectroscopy is suited to analyze the carotenoid kinetic of stress effects and recovery.

  10. A novel cupping-assisted plasma treatment for skin disinfection

    Science.gov (United States)

    Xiong, Zilan; Graves, David B.

    2017-02-01

    A novel plasma treatment method/plasma source called cupping-assisted plasma treatment/source for skin disinfection is introduced. The idea combines ancient Chinese ‘cupping’ technology with plasma sources to generate active plasma inside an isolated, pressure-controlled chamber attached to the skin. Advantages of lower pressure include reducing the threshold voltage for plasma ignition and improving the spatial uniformity of the plasma treatment. In addition, with reduced pressure inside the cup, skin pore permeability might be increased and it improves attachment of the plasma device to the skin. Moreover, at a given pressure, plasma-generated active species are restricted inside the cup, raising local reactive species concentration and enhancing the measured surface disinfection rate. A surface micro-discharge (SMD) device is used as an example of a working plasma source. We report discharge characteristics and disinfection efficiency as a function of pressure and applied voltage.

  11. Efficacy of selected disinfectants against mycobacteria and cryptosporidia.

    Science.gov (United States)

    Holton, J; Nye, P; McDonald, V

    1994-06-01

    We have tested the in-vitro efficacy of various disinfectants against clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium-intracellulare, and against the protozoon Cryptosporidium parvum. The disinfectants were tested both with and without an organic load. 'Sactimed sinald' (a quaternary ammonium compound), 'Steris 20' (a peracetic acid compound) and 'Pentapon DC1' (a beta-ene compound) were all equally as effective as 'Cidex' (glutaraldehyde) against all the mycobacteria tested, as well as C. parvum. 'Virkon' (a per-oxygen compound) and 'Phoraid' (an iodine compound) were less effective than glutaraldehyde. 'Pentapon DHY' (a beta-ene compound) was ineffective against any of the organisms tested. We have also assessed a method of determining disinfectant efficacy using [35S]-methionine labelling of proteins, which appears promising, although it requires further evaluation.

  12. Disinfection procedures for in vitro propagation of Anthurium

    Directory of Open Access Journals (Sweden)

    Silva Jaime A. Teixeira da

    2015-06-01

    Full Text Available Disinfection of plant material is the most important step of the tissue culture protocol. In this process, an attempt is made to eliminate microbial contaminants from the surface and interior of plant material, thus giving the explant a fighting chance at survival in vitro. Initial cultures of Anthurium species and cultivars, which are usually established from ex vitro material grown in a greenhouse, pots or in the field, easily contaminate the in vitro milieu. This review highlights the differences in disinfection protocols that exist for different species or cultivars of Anthurium. The protocol needs to be adjusted based on the material used: spadices, spathes, seeds, leaves, or roots. Regrettably, most of the currently published protocols, derived from a literature that spans over 100 published papers, have numerous weaknesses and flaws in the information provided pertaining to disinfection and infection levels. Advice for future Anthurium researchers should thus be followed cautiously.

  13. The influence of disinfectants on mutagenicity and on toxicity of urban waste water; Valutazione di trattamenti di disinfezione di acque reflue urbane mediante test di tossicita' e di mutagenesi

    Energy Technology Data Exchange (ETDEWEB)

    Monarca, S. [Brescia Univ., Brescia (IT). Dipt. di Medicina Sperimentale e Applicata] [and others

    1999-12-01

    The aim of the research was to study the influence of disinfectants alternative to chlorine, such as chlorine dioxide, ozone, peracetic acid and UV radiation, have on the formation of mutagenic and toxic compounds in waste water disinfection. Preliminary results are presented and discussed. [Italian] Scopo del lavoro e' stato lo studio dell'azione antimicrobica di diversi disinfettanti su acque reflue urbane dopo trattamento secondario, correlando tale parametro con l'attivita' tossica e genotossica prodotta dalla disinfezione. I risultati vengono presentati e discussi.

  14. USING MEMBRANES TO CONCENTRATE DISINFECTION BYPRODUCTS FOR SUBSEQUENT HEALTH EFFECTS STUDIES

    Science.gov (United States)

    Chemical disinfection of water is a major public health advance that has decreased dramatically water-borne disease. Disinfecting agents react with naturally occurring organic and inorganic matter in water to produce a wide variety of disinfection byproducts (DBPs). Although mo...

  15. 40 CFR 141.64 - Maximum contaminant levels for disinfection byproducts.

    Science.gov (United States)

    2010-07-01

    ... the Act, hereby identifies the following as the best technology, treatment techniques, or other means... treatment process to reduce production of bromate Chlorite Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels (b) TTHM and...

  16. Measurement and detection of radiation

    CERN Document Server

    Tsoulfanidis, Nicholas

    2015-01-01

    This fourth edition reflects recent major developments that have occurred in radiation detector materials, systems, and applications. It continues to provide the most practical and up-to-date introduction to radiation detector technology, proper measurement techniques, and analysis of results for engineers and scientists using radiation sources. New chapters emphasize the expanded use of radiation detection systems in nuclear non-proliferation, homeland security, and nuclear medicine. The book also discusses the correct ways to perform measurements following current health physics procedures.

  17. Disinfection and dewatering of wastewater solids by interstitial vapor generation.

    Science.gov (United States)

    Kramer, Timothy A; Hill, T Keith; Beckley, John

    2004-01-01

    Disinfection of wastewater solids (waste activated solids [WAS]) by interstitial vapor generation was investigated. In addition to the magnitude of disinfection, the amount of water removed and cost relative to traditional residuals disinfection processes was also examined. The process of interstitial vapor generation occurs as a result of the rapid heating of liquid in the interstices of the solid-liquid array. Intense heating causes boiling of the slurry liquid, resulting in an expanding vapor front that simultaneously dewaters the wastewater solids and contributes to the destruction of viable pathogenic microorganisms. Objectives of the study were threefold: (1) to validate disinfection of WAS using the interstitial vapor technique; (2) establish the degree of possible drying of the residuals using the techniques; and (3) establish the key operating variables for the process. Results showed a significant reduction in the most probable number of total coliforms and Escherichia coli (E. coli). Specifically, greater than four-log unit reductions were produced for both total coliform and E. coli bacteria. In addition to quantifying the reduction in bacteria, the percent solids were increased from an initial amount of 7.6% (mass basis) to a final solids content greater than 90% using optimal processing conditions. Cost comparisons were also conducted and shown to be quite favorable when compared with traditional disinfection methods such as lime addition. Because of the high level of E. coli reduction achieved, the process of interstitial vapor generation is shown to be capable of converting a class B biosolids into a class A pathogen reduced product. For example, an initial most probable number (MPN) of 1.2 x 10(6) E. coli bacteria were reduced to 19 at the extreme conditions of the process, well below the requirement of an MPN of 1000 for fecal coliform bacteria. Given its ability to disinfect and dewater wastewater solids, the interstitial vapor generation process

  18. Disinfection of irreversible hydrocolloid impression material with chlorinated compounds.

    Science.gov (United States)

    Rweyendela, I H; Patel, M; Owen, C P

    2009-06-01

    Irreversible hydrocolloid (alginate) impressions are dimensionally unstable and difficult to disinfect. To evaluate the antimicrobial efficacy of a chlorite disinfectant (Presept) and a new formulation chlorine dioxide based disinfectant (Aseptrol) on irreversible hydrocolloid (alginate) impression material. Alginate blocks were contaminated with Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans and Bacillus subtilis spores. The blocks were placed either in sterile distilled water as control, or in 48-ppm Aseptrol or Presept solution containing organic matter. Immersion times were 30 seconds, 1, 1.5, 2, 3 and 5 minutes. The blocks were then placed in sterile 0.5% sodium thiosulphate neutralizer and surviving organisms were harvested and counted using the serial dilution technique followed by culturing on appropriate media. The anti-microbial efficacy of the solution was tested for 37 days. There was a consistent significant reduction (99.99%) in all tests of vegetative organisms after immersion in the Aseptrol for 30 seconds, and for spores after 1.5 minutes. It was effective against vegetative organisms for up to 27 days for a 30-second exposure. Presept significantly reduced (99.99%) C. albicans, S. aureus and S. mutans in 30 seconds, P. aeruginosa in 60 seconds, but for B. subtilis spores took at least 5 minutes. It was effective against vegetative organisms for >37 days for a 30-second exposure. Within the limits of this study it was found that both compounds effectively disinfected the alginate in the presence of organic material, but that Aseptrol did so after an immersion time of only 1.5 minutes. This immersion time is less likely to affect the dimensional properties of the impression material. The short action time of Aseptrol may make it ideal for the disinfection of alginate impressions, and it may also find many uses for disinfection and possible sterilisation.

  19. Generation of ozone foam and its application for disinfection

    Science.gov (United States)

    Hiragaki, Keisuke; Ishimaru, Tomiya; Nakanishi, Masaru; Muraki, Ryouji; Nieda, Masanori; Yamabe, Chobei

    2015-07-01

    Generated ozone foam was applied to the disinfection of Pseudomonas fluorescens. The effect of disinfection has been confirmed experimentally and new equipment for the disinfection of hands using this ozone foam has been put on the market for the practical use. The ozone foam was produced in the foam generator after mixing the water including surfactant (30 mL/min) and air including ozone (1000 ppm = 2.14 g/m3 ~ 1600 ppm = 3.4 g/m3, 300 mL/min). The liquid-to-gas ratio is 100 L/m3. The concentration of dissolved ozone in the thin liquid films of the bubbles was about 3 mg/L which was measured by the chemical method of the KI absorption and titration of sodium thiosulfate solution. The disinfection test samples were prepared using the PET disk on which Pseudomonas fluorescens of its number of more than 108 were attached. Test sample was inserted into ozone foam set on the glass plate for one to 6 min. The survival rate log (N/N0 decreased with time and its value of about-2.6 (i.e., ~1/400) was obtained at 6 min (2 min × 3 times repeated). It was also confirmed that the ozone foam was useful for the disinfection of hands. For more effective disinfection (in case of taking a long time for foam melting), the ozone foam was broken by force and changed into ozone water by which the survival rate decreased ×4 (i.e., N/N0 = 1/10 000) at 4 ~ 6 min. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  20. The effect of various disinfectants on dental shade guides.

    Science.gov (United States)

    Huang, Peterson Y; Masri, Radi; Romberg, Elaine; Driscoll, Carl F

    2014-09-01

    Dental shade guides are used to evaluate tooth color before prosthodontic procedures and are subjected to disinfection after use. The effect of disinfection on shade guides has not been thoroughly investigated. The purpose of this study was to evaluate the effect of disinfectants on the color of shade tabs. Changes in the color (ΔE) of VITA Classical Shade Guide tabs were measured with a VITA Easyshade spectrophotometer in the CIELAB system and calculated after being subjected to Cavicide, Asepticare TB, Sporicidin, and distilled water (control) over a simulated period of 2 years. Statistical analysis was accomplished by a 2-way analysis of variance followed by the Tukey honestly significant difference (HSD) test (α=.05). A significant difference was noted in the degree of shade tab color change, depending on the type of disinfectant used (F=153.2, P<.001). No significant difference was noted in the amount of shade tab color change that occurred after disinfection among the different shade tabs used (F=0.611, P=.865), nor was a significant interaction noted between the type of disinfectant and the different shade tabs used (F=0.7, P=.919). Asepticare TB showed the least significant amount of change (ΔE=0.401), and Sporicidin (ΔE=0.889) and the control (ΔE=0.969) showed significantly more color change than Asepticare TB but less than Cavicide (ΔE=1.198). The average total CIELAB color difference for 50% human perceptibility is approximately 1 unit (under standardized laboratory conditions). In the oral cavity, however, an average change of 3.7 ΔE units could still allow teeth to be perceived as having the same color. Therefore, although the results are statistically significant, they may not be clinically important. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. Eliminating Medical Waste Liabilities Through Mobile Maceration and Disinfection

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Rankin; N. R. Soelberg; K. M. Klingler; C. W. Lagle; L. L. Byers

    2006-02-01

    Commercial medical waste treatment technologies include incineration, melting, autoclaving, and chemical disinfection. Incineration disinfects, destroys the original nature of medical waste, and reduces the waste volume by converting organic waste content to carbon dioxide and water, leaving only residual inorganic ash. However, medical waste incinerator numbers have plummeted from almost 2,400 in 1995 to 115 in 2003 and to about 62 in 2005, due to negative public perception and escalating compliance costs associated with increasingly strict regulations. High-temperature electric melters have been designed and marketed as incinerator alternatives, but they are also costly and generally must comply with the same incinerator emissions regulations and permitting requirements. Autoclave processes disinfect medical waste at much lower operating temperatures than incinerators operate at, but are sometimes subject to limitations such as waste segregration requirements to be effective. Med-Shred, Inc. has developed a patented mobile shredding and chemical disinfecting process for on-site medical waste treatment. Medical waste is treated on-site at customer facilities by shredding and disinfecting the waste. The treated waste can then be transported in compliance with Health Insurance Portability and Accountability Act of 1996 (HIPAA) requirements to a landfill for disposal as solid municipal waste. A team of Idaho National Laboratory engineers evaluated the treatment process design. The process effectiveness has been demonstrated in mycobacterium tests performed by Analytical Services Incorporated. A process description and the technical and performance evaluation results are presented in the paper. A treatment demonstration and microbiological disinfecting tests show that the processor functions as it was intended.

  2. Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

    Science.gov (United States)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth.

  3. Laboratory for Radiokrypton Dating

    Science.gov (United States)

    Lu, Z.; Bailey, K.; Jiang, W.; Müller, P.; O'Connor, T. P.; Zappala, J. C.

    2013-12-01

    Due to its simple production and transport processes in the terrestrial environment, the long-lived noble-gas isotope 81Kr (half-life = 230 kyr) is the ideal tracer for studying old water and ice in the age range of 10^5-10^6 years, a range beyond the reach of 14C. 81Kr dating, a concept pursued in the past four decades by numerous laboratories employing a variety of techniques, is now available for the first time to the earth science community at large. This is made possible by the development of ATTA-3 (Jiang et al., GCA 91, 1-6; 2012), an efficient and selective atom counter based on the Atom Trap Trace Analysis method (Chen et al., Science 286, 1139-1141; 1999). The instrument is capable of measuring both 81Kr/Kr and 85Kr/Kr ratios of environmental samples in the range of 10^-14-10^-10. For 81Kr-dating in the age range of 150 - 1,500 kyr, the required sample size is 5 - 10 micro-L STP of krypton gas, which can be extracted from approximately 100 - 200 kg of water or 40 - 80 kg of ice. For 85Kr/Kr analysis, the required sample size is generally smaller by an order of magnitude because of the isotope's higher initial abundance in the atmosphere. The Laboratory for Radiokrypton Dating is currently equipped to analyze up to 120 samples per year. With future equipment upgrades, this limit can be increased as demand grows. In the period since November 2011, the Laboratory has measured both 81Kr/Kr and 85Kr/Kr ratios in over 50 samples that had been extracted by collaborators from six different continents. The samples were from groundwater wells in the Great Artesian Basin (Australia), Guarani Aquifer (Brazil), and Locust Grove (Maryland); from brine wells of the Waste Isolation Pilot Plant (New Mexico); from geothermal steam vents in Yellowstone National Park; from near-surface ice at Taylor Glacier, Antarctica; and from deep mines in South Africa. Sample collection and purification was performed by groups including the University of Illinois at Chicago, University

  4. Phenotypes and genotypes of campylobacter strains isolated after cleaning and disinfection in poultry slaughterhouses.

    Science.gov (United States)

    Peyrat, M B; Soumet, C; Maris, P; Sanders, P

    2008-04-30

    Campylobacter is responsible for human bacterial enteritis and poultry meat is recognised as a primary source of infection. In slaughterhouses, cleaning and disinfection procedures are performed daily, and it has been suggested that disinfectant molecules might select for antibiotic resistant strains if shared targets or combined resistance mechanisms were involved. The aim of the study was to investigate if cleaning and disinfection procedures in poultry slaughterhouses select for antibiotic resistance in Campylobacter jejuni and C. coli and to determine the genotypes of isolates collected after cleaning and disinfection. Nine sampling visits were made to four French slaughterhouses. Samples were collected from transport crates and equipment surfaces, before and after cleaning and disinfection. Minimal inhibitory concentrations of the recovered C. jejuni and C. coli isolates to six antibiotics and two disinfectants were measured. The C. jejuni isolates collected from equipment surfaces after cleaning and disinfection were subjected to PCR-RFLP typing. Twenty-five C. jejuni isolates and 1 C. coli were recovered from equipment surfaces after cleaning and disinfection during five visits to three different slaughterhouses. Those isolates did not show an increased resistance to the tested antibiotics compared to isolates collected before cleaning and disinfection. Only one or two genotypes were recovered after cleaning and disinfection during single visits to each slaughterhouse. This observation suggests that such genotypes may be particularly adapted to survive cleaning and disinfection stress. Understanding the survival mechanisms of Campylobacter should facilitate the implementation of better-targeted strategies and reduce the public health burden associated with Campylobacter infection.

  5. The effect of a range of disinfectants on the dimensional accuracy of some impression materials.

    Science.gov (United States)

    Jagger, D C; Al Jabra, O; Harrison, A; Vowles, R W; McNally, L

    2004-12-01

    In this study the dimensional accuracy of two model materials; dental stone and plaster of Paris, reproduced from three commonly used impression materials; alginate, polyether and addition-cured silicone, retained by their adhesives in acrylic resin trays and exposed to four disinfectant solutions was evaluated. Ninety casts were used to investigate the effect of the four disinfectants on the dimensional accuracy of alginate, polyether and addition-cured silicone impression material. For each impression material 30 impressions were taken, half were poured in dental stone and half in plaster of Paris. The disinfectants used were Dimenol, Perform-ID, MD-520, and Haz-tabs. Measurements were carried out using a High Precision Reflex Microscope. For the alginate impressions only those disinfected by 5-minute immersion in Haz-tabs solution and in full-strength MD 520 were not adversely affected by the disinfection treatment. All polyether impressions subjected to immersion disinfection exhibited a clinically acceptable expansion. Disinfected addition-cured silicone impressions produced very accurate stone casts. Those disinfected by spraying with fill-strength Dimenol produced casts that were very similar to those left as controls, but those treated by immersion disinfection exhibited negligible and clinically acceptable expansion. The results of the studied demonstrated that the various disinfection treatments had different effects on the impression materials. It is important that an appropriate disinfectant is used for each type of impression material.

  6. Disinfection in the laboratory: theory and practice in disinfection policy in late C19th and early C20th England.

    Science.gov (United States)

    Whyte, Rebecca

    2015-03-01

    This article examines the relationship between theory and practice in nineteenth century English public health disinfection practice. Disinfection undertaken by local authorities and practised on objects, spaces and people became an increasingly common public health practice in the last quarter of the nineteenth century, and was part of a newly developed public health system of 'stamping out' disease as described by Hardy. Despite disinfection's key role in public health policy, it has thus far not received significant investigation or historiographical attending. This article explores the development of disinfection policy at local level, highlighting that despite commentators assumptions that increasingly exacting standards of disinfection required professional oversight rather than that of the 'amateur' public, there was a significant gap between laboratory based knowledge and evidence derived from practical experience. Laboratory conditions could not replicate those found in day-to-day disinfection, and there were myriad debates about how to create a mutually understandable scientific standard for testing. Despite increasing efforts to bring local disinfection in line with new ideas promulgated by central government and disinfection researchers, the mismatches between the two meant that there was greater divergence. This tension lay at the heart of the changes in disinfection theory and practice in the second half of the nineteenth century, and illustrate the complexities of the impact of germ theory on public health policy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Impact of egg disinfection of hatching eggs on the eggshell microbiome and bacterial load

    DEFF Research Database (Denmark)

    Olsen, R.; Kudirkiene, E.; Thofner, I.

    2017-01-01

    was to characterize the microbiome and aerobic bacterial load of hatching eggs before disinfection and during the subsequent disinfection steps. The study included a group of visibly clean and a group of visibly dirty eggs. For dirty eggs, an initial wash in chlorine was performed, hereafter all eggs were submitted...... aerobic conditions was established for each disinfection step. The disinfection procedure reduced the bacterial load from more than 104 cfu (initially visibly clean eggs) and 105 cfu (initially visibly dirty eggs) to less than 10 cfu per sample after disinfection for both groups of eggs. The microbiome....... In conclusion, the investigated disinfection procedure is effective in reducing the bacterial load, and by adding a chlorine wash for initially visibly dirty eggs, the microbiome of initially visibly clean and initially visibly dirty eggs had a highly similar microflora after the final disinfection step....

  8. Short-term effects of alcohol-based disinfectant and detergent on skin irritation

    DEFF Research Database (Denmark)

    Pedersen, Line Kynemund; Held, Elisabeth; Johansen, Jeanne Duus

    2005-01-01

    The most important risk factor for occupational contact dermatitis in hospital personnel is the exposure to irritants such as water, detergents and alcohol-based solutions. This study was undertaken to evaluate the short-term effects of repeated exposure to an alcohol-based disinfectant......, to a detergent and to an alcohol-based disinfectant/detergent alternately. The hardening effect in preirritated skin after a 4-week interval was also evaluated. Detergent, disinfectant and disinfectant/detergent alternately were applied daily every 15 min for 6 h for 2 days to the flexor upper arms and forearms...... evaluations, P = 0.001 and P = 0.001 and P = 0.006 and P = 0.009, respectively. No hardening effect in preirritated skin was found after a 4-week interval. In conclusion, hand disinfection with alcohol-based disinfectant or alternate use of disinfectant/detergent causes less skin irritation than hand...

  9. Controlling Legionella in hospital drinking water: an evidence-based review of disinfection methods.

    Science.gov (United States)

    Lin, Yusen E; Stout, Janet E; Yu, Victor L

    2011-02-01

    Hospital-acquired Legionnaires' disease is directly linked to the presence of Legionella in hospital drinking water. Disinfecting the drinking water system is an effective preventive measure. The efficacy of any disinfection measures should be validated in a stepwise fashion from laboratory assessment to a controlled multiple-hospital evaluation over a prolonged period of time. In this review, we evaluate systemic disinfection methods (copper-silver ionization, chlorine dioxide, monochloramine, ultraviolet light, and hyperchlorination), a focal disinfection method (point-of-use filtration), and short-term disinfection methods in outbreak situations (superheat-and-flush with or without hyperchlorination). The infection control practitioner should take the lead in selection of the disinfection system and the vendor. Formal appraisals by other hospitals with experience of the system under consideration is indicated. Routine performance of surveillance cultures of drinking water to detect Legionella and monitoring of disinfectant concentrations are necessary to ensure long-term efficacy.

  10. Effects of laboratory disinfecting agents on color stability of denture acrylic resins.

    Science.gov (United States)

    McNeme, S J; von Gonten, A S; Woolsey, G D

    1991-07-01

    This study determined the effects of chemical disinfecting agents on denture acrylic resins. Tested resins included the products CH Lucitone, Triad VLC, and Truliner. The disinfecting agents were sodium hypochlorite, Exspor, Cidex, and Wescodyne-D. Acrylic resin samples were placed in the various disinfecting agents and then evaluated for color changes at time intervals ranging from 15 minutes to 72 hours. No observable color change of any acrylic resin was seen before 2 hours. Both 1% sodium hypochlorite and 2% Cidex disinfectants produced the least discoloration of the acrylic resins, and Wescodyne-D disinfectant produced the most acrylic resin discoloration. Truliner resin discolored more than Triad VLC resin, and both underwent more color change than CH Lucitone resin. If manufacturers' recommended disinfecting times are followed, clinical and laboratory disinfection of acrylic resin dentures should cause no observable color change.

  11. [Disinfection treatment for lettuces (Lactuca sativa) and strawberries (Fragatia Chiloensis)].

    Science.gov (United States)

    López, L; Romero, J; Ureta, F

    2001-12-01

    The disinfection of vegetables and fruits is a treatment applied in order to reduce their natural contamination or processes to the product along the different steps of the food chain until its consumption. In the present work the effect of two disinfectants products was studied: grapefruit seed extract (400 ppm) for 10 min and peracetic acid (2000 ppm) for 1 min (action times assayed according to the manufacturer recommendations) and other additional times. The germicidal action was carried out against the natural contaminants of lettuces and strawberries, through the determination of the germicidal efficiency (%). Treated and untreated strawberries were also evaluated for flavor changes through a sensorial difference test, triangular test. None of the assayed products reached the 99.999% destruction of the natural contaminants according to the Chambers test. Peracetic acid was the most effective disinfectant, reaching the highest destruction percentages at a time lower than that for grapefruit seed extract. Sensory analysis showed no significant differences (p = .05) between strawberries with and without disinfection treatments, at the conditions suggested by the manufacturer.

  12. A prototype catheter designed for ultraviolet C disinfection

    DEFF Research Database (Denmark)

    Bak, Jimmy; Begovic, Tanja

    2013-01-01

    UVC light exposure, sampling and plate counting. Findings Two minutes of UVC exposure was sufficient to obtain 4 log10 disinfection for the full-length prototype catheter. This exposure corresponds to ∼40 mJ/cm2 at the catheter tip and indicates that even shorter exposure times can be achieved...

  13. Testing household disinfectants for the inactivation of helminth eggs ...

    African Journals Online (AJOL)

    2016-10-04

    Oct 4, 2016 ... Keywords: Ascaris, carbolic acid, disinfectant, eggs, inactivation, pit latrine, sanitation, sodium hypochlorite. INTRODUCTION. The lack of ... ronment providing temperature (25°C) and humidity (> 55%) are optimal. ...... The pH of the stomach is strongly acidic, but pH of the gas- trointestinal tract is in the ...

  14. Effects of disinfection, packaging and evaporatively cooled storage ...

    African Journals Online (AJOL)

    Similarly, disinfection treatment significantly (P 0.01) affected the changes in reducing, non-reducing and total sugars of mangoes during storage. Two-way interactions were significant (P 0.01) in terms of the changes in sugar content of mangoes. The benefits of the combined effect of post-harvest treatments on mangoes ...

  15. Improving the efficiency and sustainability of disinfection at a small ...

    African Journals Online (AJOL)

    driniev

    Improving the efficiency and sustainability of disinfection at a small rural water treatment plant. MNB Momba1*, N Makala1, Z Tyafa1, BM Brouckaert2, CA Buckley2 and PA Thompson3. 1Biochemistry and Microbiology Programme Unit, University of Fort Hare, P/Bag X1314, Alice 5700, South Africa. 2Pollution Research ...

  16. 9 CFR 53.6 - Disinfection of animals.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has been...

  17. A novel fiber optical device for ultraviolet disinfection of water.

    Science.gov (United States)

    Lu, Gang; Li, Chaolin; Zheng, Yinggang; Zhang, Qian; Peng, Juan; Fu, Ming

    2008-07-24

    Since there are several problems in traditional UV disinfection techniques, a highly efficient, reliable and economical method, using quartz optical fibers to deliver UV light is proposed. The principle of the experimental setup is that ultraviolet rays are gathered by a reflector and converge on a light point, the diameter of approximately 5mm. In this way UV light can be transferred into water to kill the bacteria in the water. This paper presents preliminary results on water disinfection using this new UV disinfection setup. Its suitability for application could be shown in experiments with E. coli (ATCC8099) as test microorganisms. We have optimized the distribution of the optical fibers in the water in bench-scale study. This result can provide guidance for pilot-scale and field-scale study of this new technique. The results show that the new technique had a good performance under different conditions as follows: (a) turbidity level=10.2 NTU, (b) ferric ion concentration=0.3 mg/L, and (c) humic acid concentration=5 mg/L. The new technique provides a promising approach to disinfection treatment of drinking water.

  18. Disinfection Alternatives for Small Communities in Puerto Rico

    Science.gov (United States)

    Disinfection Alternatives for Small Communities in Puerto Rico Craig Patterson1, Graciela Ramirez Toro2, Harvey Minnigh2, Cristina Maldonado3, and Rajib Sinha4 1U.S. EPA Office of Research and Development, 2Centro de Educación, Conservación e Interpretación Ambiental (CECIA),...

  19. 9 CFR 91.41 - Cleaning and disinfecting of aircraft.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfecting of aircraft. 91.41 Section 91.41 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EXPORTATION AND IMPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS...

  20. Assessment of apparent effectiveness of chemical egg disinfectants ...

    African Journals Online (AJOL)

    Aquaculture holds the potential to supplement catches as well as produce seed for restocking purposes. However, seed production of O.karongae in artificial ... of O.karongae eggs in a re-circulating system. Key words: Egg, disinfectants, incubation, recirculation, hatchability, egg treatment, mortality, Oreochromis karongae ...

  1. UASB reactor effluent disinfection by ozone and chlorine

    NARCIS (Netherlands)

    Ribeiro da Silvia, G.H.; Bruning, H.; Gerrity, D.; Daniel, L.A.

    2015-01-01

    This research studied the sequential ozone and chlorine process with respect to, the inactivation of indicator bacteria and the formation of ozone disinfection byproducts in sanitary wastewater effluent. The applied ozone doses were 5, 8 and 10 mg.O3.L-1, followed by chlorine doses of 10, 20 and 30

  2. Quality of Chlorine-Based Antiseptics and Disinfectants Circulating ...

    African Journals Online (AJOL)

    Background: Chlorine-based antiseptics and disinfectants have a stability problem especially when formulated as aqueous solutions. They tend to decompose slowly liberating chlorine on storage. Despite this instability, these products are commonly manufactured and labeled with a long shelf-life. Thus the labeled content ...

  3. Survival of Viral Biowarfare Agents in Disinfected Waters

    Directory of Open Access Journals (Sweden)

    Mary Margaret Wade

    2010-01-01

    Full Text Available Protecting civilian and military water supplies has received more attention since the United States began its war on terror in 2001. Both chlorine and bromine are used by branches of the U.S. military for disinfecting water supplies; however, limited data exists as to the effectiveness of these additives when used against viral biowarfare agents. The present study sought to evaluate the survival of selected viral biothreat agents in disinfected water. Disinfected water samples were spiked with vaccinia virus strain WR and Venezuelan equine encephalitis (VEE virus strain TC-83 each separately to a final concentration of approximately 1×106 PFU/mL, and survival was assessed by plaque assay. Both viruses were inactivated by 1 mg/L free available chlorine (FAC and 2mg/L total bromine within one hour. In conclusion, these results demonstrate that both chlorine and bromine are effective disinfectants against vaccinia virus and VEE strain TC-83 at the concentrations tested.

  4. 178 efficacy of three disinfectant formulations against multidrug ...

    African Journals Online (AJOL)

    boaz

    however not an absolute term, this implies that some living microbes may persist but the possibility of sterilization resulting from disinfection cannot be ruled out (1, 22). .... positive and Gram negative organisms. The plates were then incubated at 37oC for 24hrs in an upside down position. The zones of growth inhibition ...

  5. Indigenous plant based coagulants/disinfectants and sand filter ...

    African Journals Online (AJOL)

    An Evaluation of plant- based coagulants and disinfectant-sand filter medium for surface water treatment in Bamenda, Cameroon using bacterial analyses and turbidity were carried out. 100L of very turbid surface water (Turbidity approx. 500NTU) was pretreated with 100 seeds of Moringa oleifera, and further filtered ...

  6. Effects of Ozone and Photo‑Activated Disinfection against ...

    African Journals Online (AJOL)

    Objectives: The purpose of this study was to compare the antibacterial effects of gaseous ozone (O3) and photo‑activated disinfection (PAD) methods against Enterococcus faecalis (E. faecalis) biofilms. Materials and Methods: Sixty‑five human mandibular premolars with straight root canals were selected. After root canal ...

  7. An effective disinfection protocol for plant regeneration from shoot tip ...

    African Journals Online (AJOL)

    An effective method of disinfection protocol and micropropagation with an enhanced survival rate of explants and reduced phenol induced browning in strawberry was developed. The survival rate of three genotypes was between 89.2 - 100%. Shoot tip were able to develop into plantlet on a hormone-free MS medium when ...

  8. A practical evaluation of detergent and disinfectant solutions on ...

    African Journals Online (AJOL)

    Cleaning and disinfection agents were evaluated against selected bacteria on three surfaces: aluminium, stainless steel and fibre re-enforced plastic, used as cargo container linings and to access their effect on the surface integrity. Nine sanitation chemical solutions: benzalkonium chloride, sodium hypochlorite, nitric acid, ...

  9. Monitoring natural organic matter and disinfection by-products at ...

    African Journals Online (AJOL)

    Natural organic matter (NOM) is a complex organic material present in natural surface water. NOM can cause problems during water treatment . most notably the formation of toxic disinfection by-products. This study was undertaken in order to assess the effectiveness of some of the water treatment techniques employed by ...

  10. Assessment of the efficacy of selected disinfectant formulations ...

    African Journals Online (AJOL)

    Material and Methods: Fifty S. aureus isolates were obtained from the Microbiology unit of the University College Hospital, Ibadan and characterized by standard biochemical tests. The efficacy of the test disinfectant formulations was assessed using standard method. Antimicrobial susceptibility profile of the clinical isolates ...

  11. Improving the efficiency and sustainability of disinfection at a small ...

    African Journals Online (AJOL)

    The Alice Water Treatment Plant (AWTP) has several operating problems, which often result in poor turbidity removal and inadequate disinfection residual. Some progress has been made in upgrading the skills of plant operators, but the plant performance has failed to improve because of faulty equipment, a shortage of ...

  12. The Effect of Various Brands of Chloroxylenol disinfectants on Some ...

    African Journals Online (AJOL)

    Suspension and surface viability tests were carried out to determine the effects of various brands of chloroxylenol disinfectants on clinically important nosocomial gram negative and gram-positive organisms. Dettol and morigard brands of chloroxylenol inhibited gram-positive organisms at a dilution of 1 in 50. Tiscol brand of ...

  13. Evaluation of hospital disinfection as a means of controlling endemic ...

    African Journals Online (AJOL)

    ... Staphylococcus aureus, Bacillus megaterium, Streptococcus pyogenes, and Streptococcus spp. Minimum Effective Dilution (MED) of the disinfectant on all isolates ranged from 1:300 to1:1000. Staphylococcus aureus and Pseudomonas aeruginosa were the most resistant isolate with MED of 1:400 and 1:300 respectively.

  14. Disinfection of Dental Impressions Prior to Handling at Muhimbili ...

    African Journals Online (AJOL)

    Aim:To determine if impressions are disinfected prior to handling at the dental laboratory of the Muhimbili National Hospital. Materials and Methods: A retrospective survey of received impressions at the Dental Laboratory [June 2004 to May 2005] was obtained from the register. To determine the percentage of impressions ...

  15. Effects of ozone and photo‑activated disinfection against ...

    African Journals Online (AJOL)

    2015-04-20

    Apr 20, 2015 ... Objectives: The purpose of this study was to compare the antibacterial effects of gaseous ozone (O3) and photo‑activated disinfection (PAD) methods against Enterococcus faecalis (E. faecalis) biofilms. Materials and Methods: Sixty‑five human mandibular premolars with straight root canals were selected.

  16. Short Communication: Production of phenol-based disinfectant ...

    African Journals Online (AJOL)

    In this study, a phenol-based disinfectant was produced using vegetable soda soap as surfactant. The soap was produced by saponificaoin of palm kernel oil with sodium hydroxide crystal, followed by the addition of 10 ml of phenol to varying weights of soap. Antimicrobial analysis was done on the soap samples using disc ...

  17. Sterilization and Disinfection Procedures by Dental Practitioners in ...

    African Journals Online (AJOL)

    Objective: To assess the level of compliance with internationally recommended infection control/Centres for disease control (CDC) guidelines among Nigerian Dentists, and the perception of adequacy of such current sterilization and disinfection procedures as practised by them. Design: A questionnaire-based survey.

  18. Sterilization and Disinfection Practices in Selected Dental Clinics in ...

    African Journals Online (AJOL)

    To assess the sterilization and disinfection practices in selected dental clinics in Cameroon. The study conducted in the second half of 2009 included 41 dental clinics in 4 out of the 10 provinces in Cameroon. Questionnaire was used to obtain information about the ownership and location of the clinic, washing and packing ...

  19. Sterilization and disinfection in a private clinic | Rahim | Tanzania ...

    African Journals Online (AJOL)

    Sterilization and disinfection in a private clinic. MA Rahim. Abstract. No Abstract. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  20. 9 CFR 83.7 - Shipping containers; cleaning and disinfection.

    Science.gov (United States)

    2010-01-01

    ... the accredited veterinarian or State, Tribal, or Federal competent authority for aquatic animal health... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Shipping containers; cleaning and disinfection. 83.7 Section 83.7 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE...

  1. Violence in Adolescent Dating Relationships

    Science.gov (United States)

    Jouriles, Ernest N.; Platt, Cora; McDonald, Renee

    2009-01-01

    Beginning with a definition of dating and dating violence among adolescents, this article explores the factors which impact such violence. It concludes with a review of two school-based prevention/intervention programs (Safe Dates and The Youth Relationships Project). (Contains 1 table.)

  2. Solar disinfection improves drinking water quality to prevent diarrhea in under-five children in Sikkim, India

    Directory of Open Access Journals (Sweden)

    B B Rai

    2010-01-01

    Full Text Available Background: Solar radiations improve the microbiological quality of water and offer a method for disinfection of drinking water that requires few resources and no expertise and may reduce the prevalence of diarrhea among under-five children. Aims and Objectives: To find out the reduction in the prevalence of diarrhea in the under-five children after consumption of potable water treated with solar disinfection method. Materials and Methods: This was a population-based interventional prospective study in the urban slum area of Mazegoan, Jorethang, south Sikkim, during the period 1 st May 2007 to 30 th November 2007 on 136 children in the under-five age group in 102 households selected by random sampling. Main outcome measure was the assessment of the reduction of the prevalence of diarrhea among under-five children after consumption of potable water treated with solar disinfection method practiced by the caregivers in the intervention group keeping water in polyethylene terephthalate (PET bottles as directed by the investigators. The data were collected by the interview method using a pre-tested questionnaire prepared on the basis of socio-demographics and prevalence of diarrhea. The data were subjected to percentages and chi-square tests, which were used to find the significance. Results: After four weeks of intervention among the study group, the diarrhea prevalence was 7.69% among solar disinfection (SODIS users, while 31.82% prevalence was observed among non-users in that period; the reduction in prevalence of diarrhea was 75.83%. After eight weeks of intervention, the prevalence of diarrhea was 7.58% among SODIS users and 31.43% among non-users; the reduction in diarrhea was 75.88% in the study group. The findings were found to be statistically significant. Conclusions: In our study, we observed that the prevalence of diarrhea decreased significantly after solar disinfection of water was practiced by the caregivers keeping potable water in

  3. ESR dating of the fault rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2004-01-15

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs, grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Ulzin nuclear reactor. ESR signals of quartz grains separated from fault rocks collected from the E-W trend fault are saturated. This indicates that the last movement of these faults had occurred before the quaternary period. ESR dates from the NW trend faults range from 300ka to 700ka. On the other hand, ESR date of the NS trend fault is about 50ka. Results of this research suggest that long-term cyclic fault activity near the Ulzin nuclear reactor continued into the pleistocene.

  4. Efficacy of dental unit waterlines disinfectants on a polymicrobial biofilm.

    Science.gov (United States)

    Costa, Damien; Girardot, Marion; Bertaux, Joanne; Verdon, Julien; Imbert, Christine

    2016-03-15

    Due to their high surface-volume ratio, their laminar flow and frequent stagnation periods, dental unit waterlines (DUWL) foster the attachment of microorganisms and the development of biofilm, resulting in the continuous contamination of the outlet water from dental units; this contamination may be responsible for a potential risk of infection due to the exposure of patients and medical staff to droplet inhalation or splashed water. In this study, the anti-biofilm activity of three disinfectants recommended by dental unit manufacturers -Calbenium(©), Oxygenal 6(©) and Sterispray(©) - was evaluated. A dynamic model simulating DUWL conditions was developed and polymicrobial biofilms containing bacteria (Pseudomonas aeruginosa), fungi (Candida albicans) and Free Living Amoeba (FLA: Vermamoeba vermiformis) were allowed to form. The ability of disinfectants to reduce biofilm formation or to eradicate an already formed biofilm was evaluated. Results showed the various effects of the tested disinfectants according to their composition, concentration and the targeted species. V. vermiformis was resistant to disinfectants, regardless of the tested concentrations and the concentrations recommended by manufacturers were not the most appropriate. Results also showed that Calbenium(©) was the most effective disinfectant to reduce already formed biofilms; its maximum efficiency was observed from 0.5% on both P. aeruginosa and C. albicans compared to 2 and 3% respectively for Sterispray(©). The maximum efficiency of Oxygenal(©) was observed from 3% on P. aeruginosa but Oxygenal(©) was unable to totally eliminate C. albicans in the tested conditions, contrary to other disinfectants. Calbenium(©) was able to prevent biofilm formation efficiently even if it displayed no prophylactic activity against V. vermiformis. Overall, the FLA survival may contribute to maintaining other species. Finally the tested disinfectants were partially active against sessile microorganisms

  5. Disinfecting the iPad: evaluating effective methods.

    Science.gov (United States)

    Howell, V; Thoppil, A; Mariyaselvam, M; Jones, R; Young, H; Sharma, S; Blunt, M; Young, P

    2014-06-01

    Tablet computers are increasingly used in healthcare, but they may carry nosocomial pathogens. There are few data available on how to clean an iPad effectively for use in the clinical setting. We aimed to identify the most effective method of decontaminating the Apple iPad, without causing damage, and establish the duration of any residual effect. Following contamination with a microbial broth (meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE) and Clostridium difficile), we examined efficacy of iPad disinfection in the laboratory using six different disinfectant wipes: Sani-Cloth CHG 2% (chlorhexidine 2%/alcohol 70%), Clorox, Tristel, Trigene, soap and water, and plain cloth. Following cleaning, iPads were recontaminated to examine residual activity. After 480 Sani-Cloth CHG 2% disinfecting episodes, functional and visual analysis of iPads was performed by blinded subjects. With the exception of Clostridium difficile, Sani-Cloth CHG 2% and Clorox wipes were most effective against MRSA and VRE, and they were significantly better than the Apple-recommended plain cloth (P ≤ 0.001). A substantial residual antimicrobial effect was seen for >6h after wiping the iPad with Sani-Cloth CHG 2% despite repeated recontamination and without further disinfection. The functionality or visual appearance of the iPad was not damaged by repeated use of Sani-Cloth CHG 2% wipes. Sani-Cloth CHG 2% wipes effectively disinfect the iPad against MRSA and VRE, with a residual antibacterial effect and without causing damage. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  6. Dimensional Stability of Color-Changing Irreversible Hydrocolloids after Disinfection

    Directory of Open Access Journals (Sweden)

    Khaledi AAR

    2015-03-01

    Full Text Available Statement of Problem: Disinfection of dental impressions is a weak point in the dental hygiene chain. In addition, dental office personnel and dental technicians are endangered by cross-contamination. Objectives: This study aimed to investigate the dimensional stability of two color-changing irreversible hydrocolloid materials (IH after disinfection with glutaraldehyde. Materials and Methods: In this in vitro study, impressions were made of a master maxillary arch containing three reference inserts on the occlucal surface of the left and right maxillary second molars and in the incisal surface of the maxillary central incisors. Two types of color-changing irreversible hydrocolloid (tetrachrom, cavex were used. Glutaraldehyde 2% was used in two methods of spraying and immersion to disinfect the impressions. The control group was not disinfected. Casts were made of type IV gypsum. The linear dimensional change of the stone casts was measured with a profile projector. For statistical analysis, Kruskall-Wallis and Mann-Witney tests were used (α=0.05. Results: By immersion method, the casts fabricated from tetrachrom were 0.36% larger in the anteroposterior (AP and 0.05% smaller in cross arch (CA dimensions; however, the casts prepared after spraying of tetrachrom were 0.44% larger in the AP and 0.10% smaller in CA dimensions. The casts made from Cavex were 0.05% smaller in the AP and 0.02% smaller in CA dimensions after spraying and 0.01% smaller in the AP and 0.003% smaller in CA dimensions after immersion. Generally there were not significant differences in AP and CA dimensions of the experimental groups compared to the control (p > 0.05. Conclusions: Disinfection of the tested color-changing irreversible hydrocolloids by glutaraldahyde 2% did not compromise the accuracy of the obtained casts.

  7. Disinfectant choices in veterinary practices, shelters and households : ABCD guidelines on safe and effective disinfection for feline environments

    NARCIS (Netherlands)

    Addie, Diane D; Boucraut-Baralon, Corine; Egberink, Herman; Frymus, Tadeusz; Gruffydd-Jones, Tim; Hartmann, Katrin; Horzinek, Marian C; Hosie, Margaret J; Lloret, Albert; Lutz, Hans; Marsilio, Fulvio; Pennisi, Maria Grazia; Radford, Alan D; Thiry, Etienne; Truyen, Uwe; Möstl, Karin

    OVERVIEW: Regardless of whether a pathogen is viral, bacterial, parasitic, fungal or an emerging unknown, the mainstay of infectious disease control is hygiene, and the cornerstone of good hygiene is effective disinfection. CHALLENGES AND CURRENT CHOICES: Certain pathogens present a challenge to

  8. Disinfection aboard cruise liners and naval units: formation of disinfection by-products using chlorine dioxide in different qualities of drinking water.

    Science.gov (United States)

    Ufermann, Petra; Petersen, Hauke; Exner, Martin

    2011-12-01

    The world-wide deployment of cruise liners and naval units has caused an increased need for the disinfection of drinking water. The main cause for this is the unknown quality of drinking water in foreign harbours--besides the formation of bio-films due to the climatically disadvantageous conditions in the operational area. Water conduits on board are currently disinfected with calcium hypochlorite in case of microbiological contamination. Chemical and physical analyses after disinfection with calcium hypochlorite have shown that organic by-products consisting of trihalomethanes develop in considerable amounts during disinfection. Furthermore, the method is susceptible to handling errors and thus often leads to insufficient disinfection results. Hitherto, the use of other disinfection methods allowed by government regulations, especially chlorine dioxide, is not widely spread. Unlike disinfection with calcium hypochlorite, chlorine dioxide does not lead to the formation of trihalomethanes. Typical disinfection by-products (DBP) are the anions chlorite and chlorate, which are formed in oxidative processes. The formation conditions of these anions have not yet been elucidated. For this reason, the probability of the generation of inorganic by-products after disinfection with chlorine dioxide has been determined, and their occurrence in drinking water on board has been examined with respect to a possible correlation between water quality and the formation of chlorate and chlorite. Therefore, a chromatographic method was developed and validated in order to determine the periodical development of chlorate and chlorite from chorine dioxide in purified water at different pH-values as well as in actual drinking water samples from water conduits on board. The formation of the by-products chlorite and chlorate after disinfection with chlorine dioxide is influenced neither by pH-value nor by chemical properties of the disinfected water. Considering the examined conditions

  9. Comparison of disinfectant efficacy when using high-volume directed mist application of accelerated hydrogen peroxide and peroxymonosulfate disinfectants in a large animal hospital.

    Science.gov (United States)

    Saklou, N T; Burgess, B A; Van Metre, D C; Hornig, K J; Morley, P S; Byers, S R

    2016-07-01

    Effective decontamination of animal holding environments is critical for providing high quality patient care and maintaining a safe working environment. Disinfection of animal holding environments is a significant challenge during times of epidemic disease. The purpose of this study was to evaluate the disinfectant efficacy of 3 strategies for high-volume directed mist application of accelerated hydrogen peroxide and peroxymonosulfate disinfectants; 4.25% accelerated hydrogen peroxide (Accel(®) ; AHP) at a 1:16 dilution and single and double applications of 2% peroxymonosulfate solution (Virkon-S(®) ; VIR-1 and VIR-2) for decontamination of a large animal hospital environment. Experiment. After cleaning and disinfection of the hospital environment, transparencies experimentally contaminated with known concentrations of Staphylococcus aureus, Salmonella enterica and Pseudomonas aeruginosa were placed on vertical surfaces. Disinfectant solution was applied by directed mist application and, after 30 min of contact time, transparencies were collected and individually placed into tubes containing 10 ml Dey-Engley broth. The process was repeated for each disinfectant. Tenfold dilutions of each sample were plated onto tryptic soy blood agar with 5% sheep blood. Bacterial counts from transparencies exposed to disinfectants were compared with counts from control transparencies (unexposed to disinfectants) to evaluate reduction in colony forming units. The least squares mean reduction (log10 ) in colony forming units (CFUs) for S. aureus and P. aeruginosa was 1.5-2.5 logs and approximately 0.8-1.0 logs for S. enterica. Reductions were generally largest for VIR-2 and smallest for AHP, although these differences were not all statistically significant and the magnitude of differences may not be clinically relevant. For the organisms evaluated, all 3 disinfectants applied as a directed mist were effective at reducing CFUs in a veterinary hospital environment. Effective

  10. node.dating: dating ancestors in phylogenetic trees in R.

    Science.gov (United States)

    Jones, Bradley R; Poon, Art F Y

    2017-03-15

    Phylogenetic trees encode the evolutionary distances between species or populations. With sufficient information, these evolutionary distances can be rescaled over time to provide estimates of the dates of the most recent ancestors of the species. Here we present the R program node.dating, divergence-time analysis software, which uses a maximum-likelihood method to estimate the dates of the internal nodes of a phylogenetic tree. node.dating is available as a part of the R v3.30 package ape v4.0 (cran.r-project.org). node.dating is also available in the GitHub repository: https://github.com/brj1/node.dating , along with supplementary software and tests. brj1@sfu.ca. Supplementary data are available at Bioinformatics online.

  11. Evaluation of the Solar Water Disinfection Method Using an Ultraviolet Measurement Device

    Science.gov (United States)

    Leung, H.

    2015-12-01

    Drinking water security is a growing problem for the population of planet Earth. According to WHO, more than 750 million people on our planet lack access to safe drinking water, resulting in approximately 502,000 diarrhoea deaths in 2012. In order to solve this problem, the Swiss water research institute, Eawag, has developed a method of solar water disinfection, called, "SODIS" The theory of SODIS is simple to understand: a clear plastic bottle filled with water is placed under full sunlight for at least 6 hours. The ultraviolet radiation kills the pathogens in the water, making the originally contaminated water safe for drinking. In order to improve this method, Helioz, an Austrian social enterprise, has created the WADI, a UV measurement device which determines when water is safe for drinking using the SODIS method. When using the WADI, the device should be placed under the sun and surrounded with bottles of water that need to be decontaminated. There is a UV sensor on the WADI, and since the bottles of water and the WADI will have equal exposure to sunlight, the WADI will be able to measure the impact of the sunlight on the contaminated water. This experiment tests the accuracy of the WADI device regarding the time interval needed for contaminated water to be disinfected. The experiment involves using the SODIS method to purify bottles of water contaminated with controlled samples of E. coli. Samples of the water are taken at different time intervals, and the E. coli levels are determined by growing the bacteria from the water samples on agar plates. Ultimately, this helps determine when the water is safe for drinking, and are compared against the WADI's measurements to test the reliability of the device.

  12. Solar water disinfection by photocatalytic singlet oxygen production in heterogeneous medium

    Energy Technology Data Exchange (ETDEWEB)

    Villen, Laura; Manjon, Francisco; Garcia-Fresnadillo, David; Orellana, Guillermo [Laboratory of Applied Photochemistry, Department of Organic Chemistry, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2006-12-01

    Water disinfection in isolated rural areas of less-developed countries poses specific problems since operational expenses must be low, chemicals are not easily deployable and qualification of operators is scarce. Therefore, alternative technologies to the widespread chlorination have been considered for household use. We have evaluated the viability of a photocatalytic process for bacteria inactivation with sunlight, affordable 0.8m{sup 2} compound parabolic collectors (CPC) and an UV-vis absorbing ruthenium (II) tris-chelate complex immobilised (2gm{sup -2}) onto porous silicone as singlet molecular oxygen generator. We have tested the efficiency of two CPC prototypes with different configuration of the photosensitising material, namely, a coaxial- and a fin-type one. Mineral water flowing at 2Lmin{sup -1} and spiked with Escherichia coli or Enterococcus faecalis was subject to the photocatalytic treatment for 5h (a 0.6-0.8MJm{sup -2}L{sup -1} dose of 360-700nm sunlight radiation at 40{sup o}N latitude). Using the fin-type reactor under these conditions, the bacterial survival for 10{sup 4} to 10{sup 2}CFUmL{sup -1} initial concentrations drop to ca. 1% and 0.1% for E. coli and E. faecalis, respectively. The average disinfection rates are similar with both photoreactor designs, regardless the bacteria used (ca. 2x10{sup 4} and 2x10{sup 6}CFUL{sup -1}h{sup -1} for the low and the high initial levels of bacteria, respectively). The novel systems are comparable to or better than solid-supported TiO{sub 2} photocatalysts at inactivating waterborne bacteria. (author)

  13. The effect of immersion disinfection procedures on dimensional stability of two elastomeric impression materials.

    Science.gov (United States)

    Melilli, Dario; Rallo, Antonio; Cassaro, Angelo; Pizzo, Giuseppe

    2008-12-01

    The aim of this study was to determine the effect of immersion disinfection procedures on the dimensional stability of two elastomeric impression materials. Impressions of a stainless steel die were made with polyether (PE) and with addition-polymerized silicone rubber (PVS). The test specimens underwent disinfection treatment by immersion in two commercially available solutions containing quaternary ammonium compounds (Sterigum Powder, SP) and glutaraldehyde plus an amino derivative (MD520, MD), respectively. The impressions were measured at 4 different time points: before any disinfection treatment (T0); after the first disinfection (T1); 6 hours after the first disinfection (T2); after the second disinfection, carried out 6 hours after the first one (T3). Impressions which were not disinfected served as controls. When both impression materials were disinfected with SP, significant differences were detected among all measurements (P 0.05). On the other hand, when MD was used, significant differences were found when T0 measurement was compared to T1, T2 and T3 measurements (P = 0.0043 for PE, and P = 0.0014 for PVS). The dimensional change of all material/disinfectant combinations was always disinfection on the dimension of elastomers in SP or MD are not clinically relevant.

  14. Resistance to disinfection of a polymicrobial association contaminating the surface of elastomeric dental impressions.

    Science.gov (United States)

    Giammanco, Giovanni M; Melilli, Dario; Rallo, Antonio; Pecorella, Sonia; Mammina, Caterina; Pizzo, Giuseppe

    2009-04-01

    The aim of this study was to evaluate the ability to resist disinfection of a polymicrobial association contaminating the surface of dental impressions obtained with two different elastomers: a polyether (Impregum) and an addition-polymerized silicone (Elite). Impressions were contaminated with a mixture of three biofilm-forming microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) and disinfected immediately after contamination, or after microbial layers were allowed to develop during a six-hour storage. Two commercial disinfectants were tested: MD 520 containing 0.5% glutaraldehyde and Sterigum Powder without glutaraldehyde. Residual contamination was recovered by mechanical rinsing immediately after disinfection and after a six-hour storage of disinfected impressions, and assessed by colony counting. Both disinfectants tested were shown to be effective in reducing the microbial presence on the impression materials, achieving at least a 102 reduction of microbial counts compared to water rinsing. However, Sterigum was generally less effective on the Elite elastomer and could not grant disinfection on six-hour aged P. aeruginosa and C. albicans microbial layers. The results of this study suggest that the materials used for the impressions influence the efficacy of disinfection. Disinfectants should be tested according to conditions encountered in everyday clinical practice and the need for immediate disinfection of impressions should be clearly indicated by manufacturers.

  15. Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

    Science.gov (United States)

    Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

    2014-10-21

    Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

  16. Evaluation of efficacy of disinfectants against Salmonella from the feed industry.

    Science.gov (United States)

    Møretrø, T; Vestby, L K; Nesse, L L; Storheim, S E; Kotlarz, K; Langsrud, S

    2009-03-01

    To evaluate disinfectants against Salmonella under conditions relevant for the feed industry. A survey on the use of disinfectants in feed industry showed that a range of different types was used. Nine disinfectants, reflecting the most commonly used active ingredients, were tested for bactericidal activity on Salmonella isolated from the feed industry. All disinfectants were efficient against Salmonella in suspension. The bactericidal effect varied considerably between different types of active compounds on bacteria dried on surfaces or grown as biofilm. Tenside-based disinfectants and hypochlorite were found to have low bactericidal activity and the efficiency was significantly reduced when the ratio of amount disinfectant per cell decreased. It was shown that concentrations of 70-80% ethanol were effective against Salmonella. Among the disinfectants tested a product containing 70% ethanol was most efficient followed by Virkon S. Many disinfectants had low bactericidal activity against Salmonella at surfaces while Virkon S and a product containing 70% ethanol were most effective. Another advantage of ethanol-based disinfectants is evaporation of ethanol, resulting in low residual water after use. Use of the disinfectants found to be efficient against surface associated Salmonella, may assist the industry in combating Salmonella.

  17. Evaluation of current and novel protocols for disinfection of airplane passenger footwear under simulated conditions.

    Science.gov (United States)

    Amass, Sandra F; Schneider, Jessica L; Gaul, Angela M

    2005-09-30

    Aerobic bacterial culture was used to compare the effectiveness of the current USDA footwear disinfection protocol for airplane passengers contacting livestock to a novel protocol. The current protocol consists of brushing and dipping shoe soles in 1% Virkon S. The number of bacteria was not different between shoes treated with the current protocol and untreated shoes. No shoes met the standard for disinfection after the current disinfection protocol was completed. The novel protocol consisted of brushing shoe soles, wiping soles with a cotton towel soaked in 1% Virkon S, and drying soles with paper towels. The number of bacteria was less (P<0.0001) on treated shoes compared to control shoes. Eighteen of 20 shoes (90%) cleaned using the novel protocol met the standard for disinfection. Direct comparison of the current and novel protocols found that the number of bacteria cultured was less (P<0.0001) after implementing the novel protocol compared to implementing the current protocol. Again, no shoes treated using the current protocol met the standard for disinfection after the current protocol was completed. Sixteen and 17 of 20 shoes (80--85%), respectively, met the standard for disinfection after the novel protocol was completed. Under conditions of this study, current US airport footwear disinfection protocols were inadequate to disinfect footwear when using aerobic bacteria as a marker for disinfection. We recommend implementation of the novel footwear disinfectant protocol for select passengers from international flights.

  18. In-Use Evaluation of Peracetic Acid for High-Level Disinfection of Endoscopes.

    Science.gov (United States)

    Chenjiao, Wu; Hongyan, Zhang; Qing, Gu; Xiaoqi, Zhong; Liying, Gu; Ying, Fang

    2016-01-01

    Many high-level disinfectants have been used for disinfection of endoscopes such as 2% glutaraldehyde (GA), 0.55% ortho-phthalaldehyde (OPA), and peracetic acid (PAA). Both GA and OPA are widely used in disinfection of endoscopes and have been previously discussed, but there is little research on the practical use of PAA as an endoscope disinfectant. An experimental model of a flexible gastrointestinal endoscope being contaminated with 9 strains of microorganism was designed. After the cleaning and disinfecting procedure was completed, we evaluated the biocidal activity (850 ppm PAA, 2% GA, and 0.55% OPA) on our flexible gastrointestinal endoscope model. We also evaluated sterilization effectiveness of PAA on other bacteria, including some antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile). The residual bacterial colony count number of the PAA-disinfected endoscope was significantly lower than that of the GA- and OPA-disinfected endoscopes. The biocidal effect and efficiency of the endoscope disinfection by PAA appeared to be better than either the GA- or OPA-disinfected endoscope. PAA has demonstrated a good sterilization effect on other bacterial species; of particular note are common antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile. The results of this study demonstrate that PAA is a fast and effective high-level disinfectant for use in the reprocessing of flexible endoscopes.

  19. Radiation Therapy

    Science.gov (United States)

    ... Be extra careful not to spend time with children or pregnant women. Internal Radiation Therapy Makes You Give Off Radiation With systemic radiation, your body fluids ( urine , sweat, and saliva ) will give off radiation for a while. With ...

  20. Radiation enteritis

    Science.gov (United States)

    Radiation enteropathy; Radiation-induced small bowel injury; Post-radiation enteritis ... Radiation therapy uses high-powered x-rays, particles, or radioactive seeds to kill cancer cells. The therapy ...

  1. Efficiency of hydrogen peroxide in improving disinfection of ICU rooms.

    Science.gov (United States)

    Blazejewski, Caroline; Wallet, Frédéric; Rouzé, Anahita; Le Guern, Rémi; Ponthieux, Sylvie; Salleron, Julia; Nseir, Saad

    2015-02-02

    The primary objective of this study was to determine the efficiency of hydrogen peroxide (H₂O₂) techniques in disinfection of ICU rooms contaminated with multidrug-resistant organisms (MDRO) after patient discharge. Secondary objectives included comparison of the efficiency of a vaporizator (HPV, Bioquell) and an aerosolizer using H₂O₂, and peracetic acid (aHPP, Anios) in MDRO environmental disinfection, and assessment of toxicity of these techniques. This prospective cross-over study was conducted in five medical and surgical ICUs located in one University hospital, during a 12-week period. Routine terminal cleaning was followed by H₂O₂ disinfection. A total of 24 environmental bacteriological samplings were collected per room, from eight frequently touched surfaces, at three time-points: after patient discharge (T0), after terminal cleaning (T1) and after H₂O₂ disinfection (T2). In total 182 rooms were studied, including 89 (49%) disinfected with aHPP and 93 (51%) with HPV. At T0, 15/182 (8%) rooms were contaminated with at least 1 MDRO (extended spectrum β-lactamase-producing Gram-negative bacilli 50%, imipenem resistant Acinetobacter baumannii 29%, methicillin-resistant Staphylococcus aureus 17%, and Pseudomonas aeruginosa resistant to ceftazidime or imipenem 4%). Routine terminal cleaning reduced environmental bacterial load (P efficiency on MDRO (15/182 (8%) rooms at T0 versus 11/182 (6%) at T1; P = 0.371). H₂O₂ technologies were efficient for environmental MDRO decontamination (6% of rooms contaminated with MDRO at T1 versus 0.5% at T2, P = 0.004). Patient characteristics were similar in aHPP and HPV groups. No significant difference was found between aHPP and HPV regarding the rate of rooms contaminated with MDRO at T2 (P = 0.313). 42% of room occupants were MDRO carriers. The highest rate of rooms contaminated with MDRO was found in rooms where patients stayed for a longer period of time, and where a patient with MDRO was

  2. [Electrochemical disinfection using the gas diffusion electrode system].

    Science.gov (United States)

    Xu, Wen-Ying; Li, Ping; Dong, Bin

    2010-01-01

    Study on the electrochemical disinfection with the H2O2 produced at the gas diffusion electrode (GDE) prepared from active carbon/ poly-tetrafluoroethylene (PTFE) was performed in the non-membrane cell. The effects of PTFE mass fraction W(PTFE) and content of the pore-forming agent in GDE m(NH4CO3), operating conditions such as pH value and oxygen flow rate Q(o2)) on disinfection were investigated, respectively. The experimental results showed that H2 O2 reached peak production at W(PTFE) of 0.5 in GDE. Addition of the pore-forming agent in the appropriate amount improved the disinfection, and this phenomenon was more obvious at neutral pH than at acidic pH. BET specific area analysis indicated that the average pore size in the membrane electrode first decreased significantly with the increasing amount of pore-forming agent, and then increased moderately. This helped the mass transfer of oxygen at the GDE. Adsorption made little or no progress to kill the bacteria during the electrolysis. Drop of pH value resulted in a rapid rise of the germicidal efficacy. This system had a broad pH coverage: when total bacterial count in raw water was 10(6) CFU x mL(-1), pH 3-10,the germicidal efficacy was greater than 80% after 30 min electrolysis using the GDE with W(Pt) of 3 per thousand as cathode. Increase of the oxygen flow rate Q(o2) within limits had little influence on the production of H2 O2 and the succeeding disinfection. On one hand, resistance of the solution and energy consumption on the disinfection increased at high oxygen flow rate, which gave rise to an increase in the operating cost of disinfection with the GDE system; on the other hand, treatment time could be reduced reasonably at high oxygen flow rate, which leads to reduction of equipment investment. Killing mechanism study showed that the direct oxidation and formation of the free radicals at the anode played a greater role in the beginning, and then the oxidative indirect effect of the generated H2 O2 at

  3. Surface Dielectric Barrier Discharge Jet for Skin Disinfection

    Science.gov (United States)

    Creyghton, Yves; Meijer, Rogier; Verweij, Paul; van der Zanden, Frank; Leenders, Paul

    A consortium consisting of the research institute TNO, the medical ­university and hospital St Radboud and two industrial enterprises is working on a non-thermal plasma treatment method for hand disinfection. The group is seeking for cooperation, in particular in the field of validation methods and potential ­standardization for plasma based disinfection procedures. The present paper describes technical progress in plasma source development together with initial microbiological data. Particular properties of the sheet shaped plasma volume are the possibility of treating large irregular surfaces in a short period of time, effective plasma produced species transfer to the surface together with high controllability of the nature of plasma species by means of temperature conditioning.

  4. Origin of disinfection by-products in cheese.

    Science.gov (United States)

    Cardador, Maria Jose; Gallego, Mercedes; Prados, Francisco; Fernández-Salguero, José

    2017-06-01

    The disinfection of water, equipment and surfaces in a cheese factory is one of the factors that can originate disinfection by-products (DBPs) in cheese. This research has focused on studying cheese factories in order to evaluate the individual contribution of each step of the cheese-making process that can contribute to the presence of DBPs in cheese. Ten factories were selected according to their salting processes (brine or dry salting). Each factory was monitored by the collection of six representative samples (factory water supply, brine solution, milk, whey, curd and cheese) in which the concentrations of up to eight chemicals were detected. The study shows that contact with brine solutions containing significant levels of DBPs is the main source of these chemicals in cheese. A minor factor is the pasteurised milk used in their manufacture.

  5. Chlorine dioxine DBPs (disinfection by-products in drinking water

    Directory of Open Access Journals (Sweden)

    C. Lasagna

    2013-01-01

    Full Text Available Since the 1970s it has been well known that, though water for human consumption is generally disinfected before being distributed along the network, the use of chemicals results in the formation of many different Disinfection By-Products (DBPs. In the case of chlorine dioxide, the most important and represented DBPs are chlorite and chlorate: after an introduction concerning the current Italian regulation on this subject, in the experimental part the results of a 7-year minitoring campaign, concerning water of different origin collected from taps in various Italian regions, are shown. The analytical technique used for the determination of chlorite and chlorate was Ion Chromatography. The result obtained are finally discussed.

  6. Dose requirements for UVC disinfection of catheter biofilms

    DEFF Research Database (Denmark)

    Bak, Jimmy; Ladefoged, Søren D.; Tvede, Michael

    2009-01-01

    doses to kill catheter biofilm. Given these doses and the power of available UVC light sources, calculation of the necessary treatment times is then possible. To determine the required doses, contaminated urinary catheters were used as test samples and UVC treated in vitro. Patient catheters (n = 67......Bacterial biofilms on permanent catheters are the major sources of infection. Exposure to ultraviolet-C (UVC) light has been proposed as a method for disinfecting the inner surface of catheters. Specification of a UVC-based device for in vivo disinfection is based on the knowledge of the required......) were collected and cut into segments of equal size and treated with various UVC doses. After treatment, the biofilm was removed by scraping and quantified by counting colony forming units. Percentage killing rates were determined by calculating ratios between UVC-treated samples and controls (no UVC...

  7. Disinfection of Biofilms in Tubes with Ultraviolet Light

    DEFF Research Database (Denmark)

    Bak, Jimmy; Begovic, Tanja

    2009-01-01

    Bacterial biofilms on long-term catheters are a major source of infection. We demonstrate here the potential of UVC light emitting diodes (LED) for disinfection purposes in catheter like tubes contaminated with biofilm. We show that UVC Light propagation is possible through teflon tubes using...... that the UVC light attenuation inside the tube can be described by an exponential function depending of tube length and various loss mechanisms. The disinfection efficiency of the UVC diodes is demonstrated on tubes contaminated artificially with a Pseudomonas aeruginosa biofilm. The tubes were connected...... the liquid light guiding principle. If the refractive index of the liquid is higher than that of the tube material light is guided inside the tube by internal reflections. To obtain a high refractive index of the liquid sodium chloride in high concentrations is added to the aqueous solution. It is shown...

  8. Effective Disinfectants for Coccidioides immitis and C. posadasii.

    Science.gov (United States)

    Vogler, Amy J; Nottingham, Roxanne; Parise, Katy L; Keim, Paul; Barker, Bridget M

    The lack of published data on effective disinfectants and contact times for use on the fungal pathogens Coccidioides immitis and C. posadasii prompted the authors to investigate the fungicidal activity of three commonly used laboratory disinfectants on arthroconidia harvested from C. immitis strain 2009. They tested the ability of 10% bleach, 70% ethanol, and Vesphene® IIse to inactivate 107 arthroconidia in an aqueous suspension within 1, 2, 5, 10, or 20 minutes of contact time. Both 10% bleach and 70% ethanol provided a 7-log10 reduction in arthroconidia in less than 1 minute, with no growth observed at any of the tested time points. Vesphene® IIse was less effective, providing a 6-log10 reduction in arthroconidia after 5 minutes, but was unable to completely inactivate all of the arthroconidia, even after 20 minutes of contact time.

  9. Subacute toxicity assessment of water disinfection byproducts on zebrafish.

    Science.gov (United States)

    Rácz, Gergely; Csenki, Zsolt; Kovács, Róbert; Hegyi, Arpád; Baska, Ferenc; Sujbert, László; Zsákovics, Ivett; Kis, Renáta; Gustafson, Ryan; Urbányi, Béla; Szende, Béla

    2012-07-01

    Disinfection of raw water is essential to the production of drinking water. However, by-products of disinfection may exert toxic effects. The potential toxic effects of two of these compounds, 4-ethylbenzaldehyde (EBA) and 2,4-difluoroaniline (DFA) were investigated using the zebrafish (Danio rerio) model. The two compounds, dissolved, were introduced in duplicate aquariums containing zebrafish in two different concentrations based on LC50 values. The aquarium water containing EBA or DFA was changed every 96 h throughout the 3 months of treatment. Behavior of the fish in each replicate was inspected twice daily. In course of treatment with both concentrations, fish exposed to DFA displayed behavior associated with visible anxiety, while EBA treated were lethargic and did not evade capture. Application of both concentrations of each component into the aquarium water resulted in dystrophic lesions in the liver, kidney and skin of the fish while preneoplastic lesions and tumors were not observed.

  10. Effectiveness of photoactivated disinfection (PAD) to kill enterococcus faecalis in planktonic solution and in an infected tooth model.

    Science.gov (United States)

    Yao, Na; Zhang, Chengfei; Chu, Chunhung

    2012-12-01

    The aim of this study was to investigate the effectiveness of photoactivated disinfection (PAD) in killing Enterococcus faecalis (EF) in planktonic solution and in an infected tooth model. One hundred and thirty-two glass tubes of EF samples with concentration of 10(14) colony forming units (CFU)/mL and photosensitizer were prepared. Sixteen groups were set up and subjected to diode laser, and then received a radiation energy dose ranging from 0.5 to 5.5 J. The bactericidal effect was measured by the mean CFU of viable EF after irradiation. Sixty single-rooted teeth were selected and contaminated with EF, and then given PAD therapy; 5.25% NaOCl irrigation and saline solution were used to disinfect the root canals. Microbial samples were taken before and after disinfection, and after 72 h recovery, and then the CFU were counted. The bactericidal effect increased linearly with the irradiation energy dose in planktonic solution. For the same irradiation energy dose, the bactericidal effect was greater in group receiving 100 mW than in that receiving 50 mW and exposed to doubled irradiation time (pPAD was significantly more effective than saline solution in reducing the number of bacterial cells within the root canals (pPAD was shown to have bactericidal effect on EF, and the bactericidal effect increased linearly with the irradiation energy dose and was superior using higher output power. PAD could decrease EF in root canals effectively, but was no more effective than 5.25% NaOCl, and PAD is more effective in planktonic solution than in root canals.

  11. Laboratory and field investigation of chemical disinfection of combined sewer overflow in Copenhagen area

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper

    We investigated the possibility to apply performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA to Escherichia coli (E. coli) and enterococcus were studied in batch scale...... and pre-field experiment. In batch scale experiment 2.5 mg·L -1 PAA removed around 4 log unit of E. coli and enterococcus from CSO with long contact time. Removal of E. coli and enterococcus from CSO were always around or above 3 log unit using 2-4 mg·L -1 PFA with short contact time in batch scale...... and pre-field experiment. There were no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA, slight toxicological effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic event. Disinfection...

  12. The effect of chemical disinfectants on the color of a porcelain shade guide.

    Science.gov (United States)

    ArRejaie, Aws S

    2014-07-01

    To evaluate the effect of long term utilization of chemical disinfectants on the color of porcelain shade guides. three chemical disinfectants were used in this study: Minuten spray, Lysol ICQuaternary Disinfectant Cleaner (QDC), and Lysol IC Ready to Use Disinfectant Cleaner (RDC). Simulation of disinfecting cycles for one year, two years, and three years were done on Vita 3D master shade guide. Color differences were determined by visual inspection and analyzing ΔE. ΔE values were significantly below the perceptible (ΔE=1) and the clinically acceptable (ΔE=3.7) thresholds. Simulated utilization of Minuten Spray, Lysol IC (QDC), and Lysol (RDC) disinfectants for up to three years didn't cause a clinically significant difference in the color of VITA Toothguide 3D-Master Shade Guide.

  13. Activity of disinfectants against foodborne pathogens in suspension and adhered to stainless steel surfaces

    Directory of Open Access Journals (Sweden)

    Tatiane Karen Cabeça

    2012-09-01

    Full Text Available The purpose of this study was to investigate and compare the efficacy of various disinfectants on planktonic cells and biofilm cells of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli. Numbers of viable biofilm cells decreased after treatment with all tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against biofilm cells, while biguanide was the least effective. Scanning electron microscopy observations revealed that cells adhered on stainless steel surface after treatment with the disinfectants. No viable planktonic cells were observed after treatment with the same disinfectants. Based on our findings, we concluded that biofilm cells might be more resistant to disinfectants than plancktonic cells.

  14. [Investigation on dental impression disinfection knowledge grasped by medical staff in stomatological hospitals].

    Science.gov (United States)

    Deng, Li-mei; Zhao, Fu-rong

    2008-10-01

    To investigate the situation about the dental impression disinfection knowledge of the medical staff in stomatological hospitals. A questionnaire investigation was conducted on 582 medical staff in five Grade A Class Three stomatological hospitals. The investigation items included demographic characteristics and knowledge on dental impression disinfection. Of 582 subjects, 424 subjects (72.85%) thought that the dental impressions should be disinfected. 76 persons chose 75% alcohol to disinfect the dental impressions, 26 persons chose povidone iodine or glutaral, 103 persons chose sterilization machine, 180 persons chose to wash with water, and 197 persons were unknown about the sterilization methods. The status of the staff grasping knowledge on dental impression disinfection was related with the working department. Our results suggest that it is necessary to strengthen the importance of impression disinfection to medical staff in stomatological hospitals. The consciousness of protection should be enhanced to reduce the cross infection in hospitals.

  15. Chemical surface disinfection of eggs of Baltic cod, Gadus morhua L

    DEFF Research Database (Denmark)

    Overton, J L; Bruun, Morten Sichlau; Dalsgaard, Inger

    2010-01-01

    growth was observed with increased concentrations of disinfectant (3.0 × 107–1.6 × 101 CFU mL−1). Abnormalities in newly hatched larvae were not related to disinfection. Survival of the yolk sac larvae was significantly better for eggs treated with 400 mg L−1 glutaraldehyde for 10 min at 10 and 15 dph......The effect of two disinfectants on eggs and larvae of Baltic cod, Gadus morhua, was investigated. The eggs were disinfected for 10 min using various concentrations of either glutaraldehyde (100, 200, 400, 600 and 800 mg L−1) or iodophor (10, 50, 100 and 150 mg L−1), 1–4-days post......-fertilization. Bactericidal effect of disinfection, survival to hatching, hatching success and larval abnormalities were assessed. Larval survival was recorded at 5-, 10- and 15-days post-hatch (dph). Although Baltic cod eggs have an unusually thin chorion, they could tolerate surface disinfection. A reduction in bacterial...

  16. Efficacy of a new premilking teat disinfectant containing a phenolic combination for the prevention of mastitis.

    Science.gov (United States)

    Oliver, S P; Gillespie, B E; Lewis, M J; Ivey, S J; Almeida, R A; Luther, D A; Johnson, D L; Lamar, K C; Moorehead, H D; Dowlen, H H

    2001-06-01

    A teat disinfectant containing a phenolic combination was evaluated in a natural exposure study in two dairy research herds. Premilking teat disinfection was compared with a negative control using a split-udder experimental design. In both herds, premilking and postmilking teat disinfections with the phenolic combination were significantly more effective in preventing new intramammary infection (IMI) than was postmilking teat disinfection only. Clinical mastitis and new IMI by Streptococcus uberis, Streptococcus dysgalactiae, Gram-negative pathogens, and coagulase-negative Staphylococcus species were significantly lower in quarters of cows with teats predipped and postdipped than in quarters with teats postdipped only. No chapping or teat skin irritation was observed. Premilking teat disinfection with the phenolic combination in association with good udder preparation and postmilking teat disinfection can further reduce the occurrence of new IMI by numerous mastitis pathogens during lactation.

  17. Solar disinfection of drinking water and oral rehydration solutions

    Energy Technology Data Exchange (ETDEWEB)

    Acra, A.; Raffoul, Z.; Karahagopian, Y.

    1984-01-01

    This document provides concise information on oral rehydration therapy for the control of diarrheal diseases in developing countries; however, the main emphasis has been placed on the disinfection of oral rehydration solutions, or the water used in their preparation, as achieved by exposure to sunlight in transparent containers. The fundamental principles of solar energy are presented as well as studies which demonstrate the efficacy of the method. 2 figures, 6 tables.

  18. A practical evaluation of detergent and disinfectant solutions on ...

    African Journals Online (AJOL)

    Student01

    2012-01-06

    Jan 6, 2012 ... disinfection studies, corrosion studies and the index of the two can assist the food and allied industries in making cost-effective ..... Bacteria. Surface. Log10 reduction for various test solutions. 2QAS DSM NaOCl HNO3. NaOH PAA LEV ATS SDS. E. coli K12. AL3. 4.0. 4.0. 4.0. 4.0. 4.0. 4.0. 4.0. 2.5. 4.0. SS.

  19. Effectiveness of different antimicrobial agents in disinfection of guttapercha cones

    OpenAIRE

    Ramos-Meléndez, Alexander; Escuela de Pregrado de la Facultad de Odontología de la Universidad Nacional Mayor de San Marcos; Ramos-Perfecto, Donald; Departamento Académico de Ciencias Básicas de la Facultad de Odontología de la Universidad Nacional Mayor de San Marcos, Perú.

    2015-01-01

    Objective: To determine the effectiveness of various antimicrobial agents in disinfection of gutta-percha, was the aim of the study. Methodology: 40 cones were cultivated in Brain Heart Infusion (BHI) culture medium at 37 ° C for 24 hours to see if there was bacterial growth. These same cones were divided into five groups to be introduced in the antimicrobial solutions: 2% chlorhexidine, hydrogen peroxide 3% sodium hypochlorite 2.5% ethyl alcohol 70% and 10% povidone iodine for a time immersi...

  20. Disinfectants and antiseptics used in mollusc hatcheries and nurseries

    OpenAIRE

    Francois, Cyrille; Pepin, Jean-francois

    2005-01-01

    Increasing development of aquaculture business has thrown up new requirements in terms of prevention and control of mollusc diseases. In closed structures, one way to reduce infectious risk is to make use of anti-infectives . Specific drugs like antibiotics should be used only for therapeutic purpose against identified agents. Less specific anti-infectives like disinfectants could be employed for preventive and also for curative goals against causal pathogens and opportunist agents. A critica...

  1. Effect of two disinfectant treatments on laboratory analyses.

    OpenAIRE

    Ball, M J

    1987-01-01

    Inactivation of human immunodeficiency virus (HIV), the retrovirus associated with the acquired immune deficiency syndrome (AIDS), can be achieved both by heating at 56 degrees C and by chemical disinfection with beta-propiolactone (BPL). Such treatment of specimens from patients with suspected AIDS or antibodies to HIV could reduce any occupational risk to laboratory staff. This study demonstrates the effects of these treatments on laboratory analyses. Heat treatment of plasma caused clinica...

  2. Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

    Directory of Open Access Journals (Sweden)

    Takashi Furukawa

    2017-07-01

    Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

  3. Chloramination of wastewater effluent: Toxicity and formation of disinfection byproducts.

    Science.gov (United States)

    Le Roux, Julien; Plewa, Michael J; Wagner, Elizabeth D; Nihemaiti, Maolida; Dad, Azra; Croué, Jean-Philippe

    2017-08-01

    The reclamation and disinfection of waters impacted by human activities (e.g., wastewater effluent discharges) are of growing interest for various applications but has been associated with the formation of toxic nitrogenous disinfection byproducts (N-DBPs). Monochloramine used as an alternative disinfectant to chlorine can be an additional source of nitrogen in the formation of N-DBPs. Individual toxicity assays have been performed on many DBPs, but few studies have been conducted with complex mixtures such as wastewater effluents. In this work, we compared the cytotoxicity and genotoxicity of wastewater effluent organic matter (EfOM) before and after chloramination. The toxicity of chloraminated EfOM was significantly higher than the toxicity of raw EfOM, and the more hydrophobic fraction (HPO) isolated on XAD-8 resin was more toxic than the fraction isolated on XAD-4 resin. More DBPs were also isolated on the XAD-8 resin. N-DBPs (i.e., haloacetonitriles or haloacetamides) were responsible for the majority of the cytotoxicity estimated from DBP concentrations measured in the XAD-8 and XAD-4 fractions (99.4% and 78.5%, respectively). Measured DBPs accounted for minor proportions of total brominated and chlorinated products, which means that many unknown halogenated compounds were formed and can be responsible for a significant part of the toxicity. Other non-halogenated byproducts (e.g., nitrosamines) may contribute to the toxicity of chloraminated effluents as well. Copyright © 2017. Published by Elsevier B.V.

  4. Antifungal efficacy of hydrogen peroxide in dental unit waterline disinfection.

    Science.gov (United States)

    Szymańska, Jolanta

    2006-01-01

    The concentration and composition of fungal flora in dental unit waterlines (DUWL) were evaluated. For this purpose, water samples from unit reservoirs and high-speed handpieces, and biofilm samples from the waterline walls from units were collected. Subsequently, analogous samples from DUWL were taken before and after disinfection using agent containing hydrogen peroxide. In the examined samples, the yeast-like fungi Candida albicans and Candida curvata were found. The following species of mould were also identified: Aspergillus amstelodami, Aspergillus fumigatus, Aspergillus glaucus group, Aspergillus (=Eurotium herbariorum) repens, Citromyces spp., Geotrichum candidum, Penicillium (glabrum) frequentans, Penicillium pusillum, Penicillium turolense and Sclerotium sclerotiorum (Sclerotinia sclerotiorum). Before disinfection, Candida curvata and Candida albicans constituted the greatest proportion of the total fungi in the reservoirs water; in the water of handpieces--Candida albicans and Aspergillus glaucus group; and in the biofilm samples--Aspergillus glaucus group and Candida albicans. After disinfection, in all 3 kinds of samples, Candida albicans prevailed, constituting from 31.2-85.7 % of the total fungi. The application of agent containing hydrogen peroxide caused a significant decrease both in the number of total fungi and individual fungal species, which confirms the product effectiveness in fungal decontamination of DUWL.

  5. Thermodynamic properties of an emerging chemical disinfectant, peracetic acid.

    Science.gov (United States)

    Zhang, Chiqian; Brown, Pamela J B; Hu, Zhiqiang

    2017-11-27

    Peracetic acid (PAA or CH3COOOH) is an emerging disinfectant with a low potential to form carcinogenic disinfection by-products (DBPs). Basic thermodynamic properties of PAA are, however, absent or inconsistently reported in the literature. This review aimed to summarize important thermodynamic properties of PAA, including standard Gibbs energy of formation and oxidation-reduction (redox) potential. The standard Gibbs energies of formation of CH3COOOH(aq), CH3COOOH(g), CH3COOOH(l), and CH3COOO(aq)- are -299.41kJ·mol-1, -283.02kJ·mol-1, -276.10kJ·mol-1, and -252.60kJ·mol-1, respectively. The standard redox potentials of PAA are 1.748V and 1.005V vs. standard hydrogen electrode (SHE) at pH 0 and pH 14, respectively. Under biochemical standard state conditions (pH 7, 25°C, 101,325Pa), PAA has a redox potential of 1.385V vs. SHE, higher than many disinfectants. Finally, the environmental implications of the thermodynamic properties of PAA were systematically discussed. Those properties can be used to predict the physicochemical and biological behavior of aquatic systems exposed to PAA. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Photodynamic therapy: An adjunct to conventional root canal disinfection strategies.

    Science.gov (United States)

    Singh, Shipra; Nagpal, Rajni; Manuja, Naveen; Tyagi, Sashi Prabha

    2015-08-01

    Although chemical-based root canal disinfectants are important to reduce microbial loads and remove infected smear layer from root dentin, they have only a limited ability to eliminate biofilm bacteria, especially from root complexities. This paper explores the novel photodynamic therapy (PDT) for antimicrobial disinfection of root canals. The combination of an effective photosensitizer, the appropriate wavelength of light and ambient oxygen is the key factor in PDT. PDT uses a specific wavelength of light to activate a non-toxic dye (photosensitizer), leading to the formation of reactive oxygen species. These reactive oxygen molecules can damage bacterial proteins, membrane lipids and nucleic acids, which promote bacterial cell death. In, addition PDT may enhance cross-linking of collagen fibrils in the dentin matrix and thereby improving dentin stability. The concept of PDT is plausible and could foster new therapy concepts for endodontics. The available knowledge should enable and encourage steps forward into more clinical-oriented research and development. This article discusses PDT as related to root canal disinfection, including its components, mechanism of action, reviews the current endodontic literature and also highlights the shortcomings and advancements in PDT techniques. © 2014 Australian Society of Endodontology.

  7. Photocatalytic Enhancement for Solar Disinfection of Water: A Review

    Directory of Open Access Journals (Sweden)

    J. Anthony Byrne

    2011-01-01

    Full Text Available It is estimated that 884 million people lack access to improved water supplies. Many more are forced to rely on supplies that are microbiologically unsafe, resulting in a higher risk of waterborne diseases, including typhoid, hepatitis, polio, and cholera. Due to poor sanitation and lack of clean drinking water, there are around 4 billion cases of diarrhea each year resulting in 2.2 million deaths, most of these are children under five. While conventional interventions to improve water supplies are effective, there is increasing interest in household-based interventions to produce safe drinking water at an affordable cost for developing regions. Solar disinfection (SODIS is a simple and low cost technique used to disinfect drinking water, where water is placed in transparent containers and exposed to sunlight for 6 hours. There are a number of parameters which affect the efficacy of SODIS, including the solar irradiance, the quality of the water, and the nature of the contamination. One approach to SODIS enhancement is the use of semiconductor photocatalysis to produce highly reactive species that can destroy organic pollutants and inactivate water pathogens. This paper presents a critical review concerning semiconductor photocatalysis as a potential enhancement technology for solar disinfection of water.

  8. Photocatalytic disinfection of water using low cost compound parabolic collectors

    Energy Technology Data Exchange (ETDEWEB)

    McLoughlin, O.A.; Gill, L.W. [Dublin Univ. (Ireland). Dept. of Civil, Structural and Environmental Engineering; Ibanez, F.; Gernjak, W.; Malato Rodriguez, S. [Plataforma Solar de Almeria (CIEMAT), Tabemas (Spain)

    2004-11-01

    The objective of this work was to assess the effectiveness of using near UV light to disinfect water supplies for potential applications in developing countries. A pilot scale photoreactor comprised of non-tracking compound parabolic collectors installed at Plataforma Solar de Almeria was examined and a comparison of disinfection efficiency using E. coli K-12 was carried out with a reactor configuration of 3 and 1 m{sup 2} illuminated area. Tests were also carried out using suspensions of titanium dioxide (TiO{sub 2}) at concentrations ranging from 0 to 9 mg/l. The removal of E. coli K-12 from initial concentrations of 1 x 10{sup 5} CFU/ml to below the limit of detection was achieved both with and without the use of TiO{sub 2}. Levels of inactivation in 35 l of inoculated water of up to 4-log removal were achieved in under 30 min. The addition of TiO{sub 2} created an enhancement to the process only at the 3 mg/l dose. However, the results have also suggested the possibility that another disinfection mechanism, possibly governed by the frequency of intermittent UV light exposure, was regulating the overall inactivation kinetics of the trials. (Author)

  9. Effectiveness of disinfection with alcohol 70% (w/v) of contaminated surfaces not previously cleaned

    OpenAIRE

    Graziano, Maurício Uchikawa; Graziano, Kazuko Uchikawa; Pinto, Flávia Morais Gomes; Bruna, Camila Quartim de Moraes; Souza, Rafael Queiroz de; Lascala, Cesar Angelo

    2013-01-01

    OBJECTIVE: To evaluate the disinfectant effectiveness of alcohol 70% (w/v) using friction, without previous cleaning, on work surfaces, as a concurrent disinfecting procedure in Health Services. METHOD: An experimental, randomized and single-blinded laboratory study was undertaken. The samples were enamelled surfaces, intentionally contaminated with Serratia marcescens microorganisms ATCC 14756 106 CFU/mL with 10% of human saliva added, and were submitted to the procedure of disinfection W...

  10. Evaluation of different sterilization and disinfection methods on commercially made preformed crowns

    OpenAIRE

    Yilmaz Y; Guler C

    2008-01-01

    The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM). Preformed crowns (NuSmile Primary Anterior Crown (NSC), Kinder Krowns (KK), Pedo Pearls (PP) and polycarbonate crowns (PC)) were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group); steam aut...

  11. Disinfection methods in general practice and health authority clinics: a telephone survey

    OpenAIRE

    Farrow, S.C.; Kaul, S.; Littlepage, B.C.

    1988-01-01

    Concern about the epidemic of the acquired immune deficiency syndrome led to discussions in one health district about the dangers of cross-infection from instruments in general practice and health authority clinics. In order to establish what current disinfection practices were in use a telephone survey was adopted as a quick and easy method of data collection. Information was collected on who was responsible for disinfection as well as details of how each instrument was disinfected. Results ...

  12. Investigations into the efficacy of different procedures for surgical hand disinfection between consecutive operations.

    Science.gov (United States)

    Rehork, B; Rüden, H

    1991-10-01

    In order to examine whether thorough surgical hand disinfection (handwashing plus hand disinfection) between consecutive operations is necessary, tests were carried out simulating normal clinical conditions. The tests were performed according to the guidelines for the evaluation of disinfection procedures of the German Society for Hygiene and Microbiology. Surgical hand disinfection was as follows: handwashing with soap without antimicrobial additives and subsequent 5-min disinfection with 60% n-propanol. This was followed by simulated operations of 30 or 120 min duration with a 30-min break between operations, during which half of the test group kept on the surgical gloves, while the other half removed them. The second surgical hand disinfection was done without prior handwashing by 50% of the test group. The disinfection time was reduced from 5 to 1 min by 50% of the test group. The results were evaluated by means of explorative data analysis and inductive statistical methods. Removing the surgical gloves during the interoperative break did not result in significantly higher numbers of colony forming units (cfu) compared with retaining the gloves. This was also the case after a subsequent handwashing. At the second surgical hand disinfection, after a simulated operation of 60 min duration (including break), there was no significant difference in the numbers of cfus between the test group who had washed their hands and those who had not. Reducing the disinfection time from 5 min to 1 min was not associated with a significant increase in the number of cfus. However, after a simulated operating time of 150 min (including the break), the second surgical hand disinfection with handwashing resulted in a significantly lower number of microorganisms than disinfection alone. In half the tests, the numbers of cfu were significantly lower when the test group disinfected their hands for 5 min rather than 1 min.

  13. The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview

    OpenAIRE

    Klironomos, Theodoros; Katsimpali, Aspasia; Polyzois, Gregory

    2015-01-01

    The aim of this paper was to overview the current scientific knowledge concerning the effect of microwave disinfection on denture related material properties. Cross-infection control in dentistry is a significant issue in everyday clinical practice due to the recent increase in some infectious diseases such as hepatitis B, C and AIDS and therefore numerous methods of disinfection have been used. The most widespread method of disinfection used in everyday practice is chemical, however, studies...

  14. Hardness of heat-polymerized acrylic resins after disinfection and long-term water immersion.

    Science.gov (United States)

    Neppelenbroek, Karin Hermana; Pavarina, Ana Cláudia; Vergani, Carlos Eduardo; Giampaolo, Eunice Teresinha

    2005-02-01

    In selecting a disinfectant for dental prostheses, compatibility between the disinfectant and the type of denture base material must be considered to avoid adverse effects on the hardness of the acrylic resin. This study investigated the hardness of 2 denture base resins after disinfection and long-term water immersion. Thirty-two disk-shaped specimens (13 mm in diameter and 8 mm thick) were fabricated from each resin (Lucitone 550 and QC-20), polished, stored in water at 37 degrees C for 48 hours, and submitted to hardness tests (Vickers hardness number [VHN]) before disinfection. Disinfection methods included scrubbing with 4% chlorhexidine gluconate for 1 minute, immersion for 10 minutes in 1 of the tested disinfectant solutions (n=8) (3.78% sodium perborate, 4% chlorhexidine gluconate, or 1% sodium hypochorite), and immersion in water for 3 minutes. The disinfection procedures were repeated 4 times, and 12 hardness measurements were made on each specimen. Control specimens (not disinfected) were stored in water for 56 minutes. Hardness tests (VHN) were also performed after 15, 30, 60, 90, and 120 days of storage in water. Statistical analyses of data were conducted with a repeated measures 3-way analysis of variance (ANOVA) and Tukey post-hoc test (alpha=.05). Mean values +/- SD for Lucitone 550 (16.52 +/- 0.94 VHN) and QC-20 (9.61 +/- 0.62 VHN) demonstrated a significant (P disinfection, regardless of material and disinfectant solutions used (Lucitone 550: 15.25 +/- 0.74; QC-20: 8.09 +/- 0.39). However, this effect was reversed after 15 days of storage in water. Both materials exhibited a continuous increase (P disinfection regardless of the disinfectant solution used.

  15. National Date Palm Germplasm Repository

    Science.gov (United States)

    The National Clonal Germplasm Repository for Citrus & Dates (NCGRCD), located in Riverside, California USA, is a project of the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA). The NCGRCD maintains a collection of germplasm of date palm (Phoneix dactylifera ...

  16. 75 FR 16516 - Dates Correction

    Science.gov (United States)

    2010-04-01

    ... From the Federal Register Online via the Government Publishing Office ] NATIONAL ARCHIVES AND RECORDS ADMINISTRATION Office of the Federal Register Dates Correction Correction In the Notices section... through 15499, the date at the top of each page is corrected to read ``Monday, March 29, 2010''. This...

  17. Batch process solar disinfection is an efficient means of disinfecting drinking water contaminated with Shigella dysenteriae type I.

    Science.gov (United States)

    Kehoe, S C; Barer, M R; Devlin, L O; McGuigan, K G

    2004-01-01

    The mortality and morbidity rate caused by Shigella dysenteriae type I infection is increasing in the developing world each year. In this paper, the possibility of using batch process solar disinfection (SODIS) as an effective means of disinfecting drinking water contaminated with Sh. dysenteriae type I is investigated. Phosphate-buffered saline contaminated with Sh. dysenteriae type I was exposed to simulated solar conditions and the inactivation kinetics of this organism was compared with that of Sh. flexneri, Vibrio cholerae and Salmonella typhimurium. Recovery of injured Sh. dysenteriae type I may be improved by plating on medium supplemented with catalase or pyruvate. Sh. dysenteriae type I is very sensitive to batch process SODIS and is easily inactivated even during overcast conditions. Batch process SODIS is an appropriate intervention for use in developing countries during Sh. dysenteriae type I epidemics.

  18. Factors involved in sustained use of point-of-use water disinfection methods: a field study from Flores Island, Indonesia.

    Science.gov (United States)

    Roma, E; Bond, T; Jeffrey, P

    2014-09-01

    Many scientific studies have suggested that point-of-use water treatment can improve water quality and reduce the risk of infectious diseases. Despite the ease of use and relatively low cost of such methods, experience shows the potential benefits derived from provision of such systems depend on recipients' acceptance of the technology and its sustained use. To date, few contributions have addressed the problem of user experience in the post-implementation phase. This can diagnose challenges, which undermine system longevity and its sustained use. A qualitative evaluation of two household water treatment systems, solar disinfection (SODIS) and chlorine tablets (Aquatabs), in three villages was conducted by using a diagnostic tool focusing on technology performance and experience. Cross-sectional surveys and in-depth interviews were used to investigate perceptions of involved stakeholders (users, implementers and local government). Results prove that economic and functional factors were significant in using SODIS, whilst perceptions of economic, taste and odour components were important in Aquatabs use. Conclusions relate to closing the gap between factors that technology implementers and users perceive as key to the sustained deployment of point-of-use disinfection technologies.

  19. Disinfection of oral rehydration solutions by sunlight.

    Science.gov (United States)

    Acra, A; Karahagopian, Y; Raffoul, Z; Dajani, R

    1980-12-06

    The use of a salt/sugar oral solution for rehydration in cases of diarrhea is being encouraged by the World Health Organization for developing areas. 1 problem so far with this treatment has been a question as to their safety when prepared with contaminated water or stored in contaminated vessels. An experiment was tried in which the recommended solution was mixed with contaminated water. Some of the containers were exposed to direct sunlight, some kept in the dark, and some stored in normal room conditions. Although the heat in the containers stored in sunlight did not rise significantly, the solutions were found to be purified. It is speculated that the germicidal action resulted from solar radiation near the ultraviolet range. The solution, itself, did not change composition. The microorganisms were not able to regrow within 24 hours after solar irradiation. 50 additional experiments confirmed the findings. It is concluded that this technique of solar irradiation of contaminated solutions will be effective. All types of containers were effective.

  20. Observations on Salmonella contamination of commercial duck farms before and after cleaning and disinfection.

    Science.gov (United States)

    Martelli, Francesca; Gosling, Rebecca J; Callaby, Rebecca; Davies, Rob

    2017-04-01

    In the European Union, statutory control of Salmonella is in place in the chicken and turkey sectors, but not in the duck sector. In this study, 14 Salmonella-positive duck farms were sampled before and after cleaning and disinfection, and once the houses had been restocked with a new flock. The cleaning and disinfection programmes used were subdivided into two main categories: ones in which a final formaldehyde disinfection step was included (1) and ones in which it was not included (2). Several types of samples were collected during the study, and faecal samples were those more frequently positive (62% of faecal samples were positive for Salmonella in comparison to 2-23% of samples from all the other sample categories) (P Salmonella-positive samples between before cleaning and disinfection (41.1%) and after cleaning and disinfection (3.1%). After restocking, the number of Salmonella-positive samples increased significantly (P Salmonella. Farms in which disinfection programme 1 was used were 5.34 times less likely to have samples positive for Salmonella after cleaning and disinfection than farms which implemented programme 2. Formaldehyde acts effectively against Salmonella even in the presence of some residual organic matter. Limited residual contamination on farms after cleaning and disinfection represents a risk of infection for young ducklings, and thorough cleaning and disinfection procedures should be implemented to reduce the carry-over of infection between flocks.

  1. Disinfection effect of a continuous-flow ultrasound/ultraviolet baffled reactor at a pilot scale.

    Science.gov (United States)

    Zhou, Xiaoqin; Yan, Yichang; Li, Zifu; Yin, Jie

    2017-07-01

    An ultrasound/ultraviolet (US/UV) baffled reactor was developed to fill the gap in ultraviolet (UV) disinfection associated with disinfection efficiency. According to the previously selected operational condition, a continuous-flow US/UV baffled reactor was continuously operated in a wastewater treatment plant at a pilot scale for nearly three months, and the disinfection influent and effluent were analyzed, including fecal coliforms, Escherichia coli, and fecal streptococci. The US/UV baffled reactor could guarantee a high effluent disinfection performance in terms of fecal coliforms removal even with the fluctuation of the secondary effluent. All the disinfected effluents satisfied the requirement of the "Pollutants Discharge Standard of Municipal Wastewater Treatment Plant in China" (fecal coliforms below 1000CFU/L for class 1A), and 87% of the tested fecal coliforms concentration in the disinfected effluent was below 100CFU/L, nearly eliminating all fecal coliforms. Further analysis of the E. coli and fecal streptococci showed the broad disinfection ability and high disinfection efficiency of the US/UV baffled reactor. The flexibility of the specific energy consumption for the disinfection system depends on the water quality. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Disinfection of bore well water with chlorine dioxide/sodium hypochlorite and hydrodynamic cavitation.

    Science.gov (United States)

    Wang, Yifei; Jia, Aiyin; Wu, Yue; Wu, Chunde; Chen, Lijun

    2015-01-01

    The effect of hydrodynamic cavitation (HC) on potable water disinfection of chemicals was investigated. The bore well water was introduced into HC set-up to examine the effect of HC alone and combination of HC and chemicals such as chlorine dioxide and sodium hypochlorite. The effect of inlet pressure and geometrical parameters on disinfection was studied using HC alone and the results showed that increasing inlet pressure and using more and bigger holes of orifice plates can result in a higher disinfection rates. When HC was combined with chemicals, HC can reduce the doses of the chemicals and shorten the time of disinfection. It was also found that the decrease in bacteria concentration followed a first-order kinetic model. As for the experiment of combination of HC and sodium hypochlorite for disinfection, HC not only improves the disinfection rate but also degrades natural organic matter and chloroform. Compared with only sodium hypochlorite disinfection, combined processes get higher disinfection rate and lower production of chloroform, particularly the pretreatment with HC enhances the disinfection rate by 32% and there is a simultaneous reduction in production of chloroform by 39%.

  3. [First results on the use of chloramines to reduce disinfection byproducts in drinking water].

    Science.gov (United States)

    Azara, Antonio; Muresu, Elena; Dettori, Marco; Ciappeddu, Pierluigi; Deidda, Antonio; Maida, Alessandro

    2010-01-01

    The presence of disinfection byproducts (DBP) in drinking water raises concerns about the safety of chlorination and is one of the problems inherent the use of surface water as a source of drinking water. In order to reduce the presence of DBP (in particular of chlorites), we evaluated the combined use of chlorine dioxide for primary disinfection and monochloramine for residual disinfection in a water purification plant and distribution system in Sardinia (Italy). The results are very encouraging. Disinfection byproducts were reduced and other parameters were found to be within the recommended standards, indicating further improvements of the purification process.

  4. Evaluation of different sterilization and disinfection methods on commercially made preformed crowns.

    Science.gov (United States)

    Yilmaz, Y; Guler, C

    2008-12-01

    The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM). Preformed crowns (NuSmile Primary Anterior Crown (NSC), Kinder Krowns (KK), Pedo Pearls (PP) and polycarbonate crowns (PC)) were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group); steam autoclaving at 134 degrees C (30 psi) for 4 min (G2); steam autoclaving at 134 degrees C (30 psi) for 12 min (G3); steam autoclaving at 121 degrees C (15 psi) for 30 min (G4); and ultrasonication in a bath containing 4% Lysetol AF for 5 min at room temperature (chemical disinfection) (G5). Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients.

  5. Decontamination of B. globigii spores from drinking water infrastructure using disinfectants

    Data.gov (United States)

    U.S. Environmental Protection Agency — Decontamination of Bacillus spores adhered to common drinking water infrastructure surfaces was evaluated using a variety of disinfectants. Corroded iron and...

  6. Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

    Science.gov (United States)

    Królasik, Joanna; Zakowska, Zofia; Krepska, Milena; Klimek, Leszek

    2010-01-01

    The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

  7. In Vitro Evaluation of Dimensional Stability of Alginate Impressions after Disinfection by Spray and Immersion Methods

    Directory of Open Access Journals (Sweden)

    Fahimeh Hamedi Rad

    2010-12-01

    Full Text Available Background and aims. The most common method for alginate impression disinfection is spraying it with disinfecting agents, but some studies have shown that these impressions can be immersed, too. The aim of this study was to evaluate the dimensional stability of alginate impressions following disinfecting by spray and immersion methods. Materials and methods. Four common disinfecting agents (Sodium Hypochlorite, Micro 10, Glutaraldehyde and Deconex were selected and the impressions (n=108 were divided into four groups (n=24 and eight subgroups (n=12 for disinfecting by any of the four above-mentioned agents by spray or immersion methods. The control group (n=12 was not disinfected. Then the impressions were poured by type III Dental Stone Plaster in a standard method. The results were analyzed by descriptive methods (mean and standard deviation, t-test, two-way analysis of variance (ANOVA and Duncan test, using SPSS 14.0 software for windows. Results. The mean changes of length and height were significant between the various groups and disinfecting methods. Regarding the length, the greatest and the least amounts were related to Deconex and Micro 10 in the immersion method, respectively. Regarding height, the greatest and the least amounts were related to Glutaraldehyde and Deconex in the immersion method, respectively. Conclusion. Disinfecting alginate impressions by Sodium Hypochlorite, Deconex and Glutaraldehyde by immersion method is not recommended and it is better to disinfect alginate impressions by spraying of Micro 10, Sodium Hypochlorite, Glutaraldehyde and immersion in Micro 10.

  8. Disinfection of Preexisting Contamination of BACILLUS CEREUS on Stainless Steel when Using Glycoconjugate Solution

    Science.gov (United States)

    Pavan, Casey; Tarasenko, Olga

    2011-06-01

    Stainless steel is ubiquitous in our modern world, however it can become contaminated. This can endanger our health. The aim of our study is to disinfect stainless steel using Bacillus cereus as a model organism. Bacillus cereus is a microbe that is ubiquitous in nature, specifically soil. B. cereus is known to cause illness in humans. To prevent this, we propose to use a glycoconjugate solution (GS) for disinfection of stainless steel after it is contamination by B. cereus spores. In this study, two GS (9, 10) were tested for disinfection effectiveness on B. cereus spores on the surface of stainless steel foil (AISI-Series 200/300/400, THERMA-FOIL, Dayville, CT 0241). The disinfection rate of each GS was assessed by exposing the steel surface to B. cereus spores first and allowing them to settle for 24 hours. GS was used to treat the contaminated surface. The steel is washed and the resulting solution is plated on tryptic soy agar (TSA) plates. The GS with the fewest colony forming unit (CFU) formed on TSA is determined to be the most efficient during disinfection. Results show that both GS demonstrate a strong ability to disinfect B. cereus spores. Between the two, GS 9 shows the highest disinfection efficacy by killing approximately 99.5% of spores. This is a drastic improvement over the 0-20% disinfection of the control. Based on this we find that studied GS do have the capacity to act as a disinfectant on stainless steel.

  9. Comparison of the effectiveness of three different disinfectant solutions in disinfection of gutta-percha cones in one minute

    Directory of Open Access Journals (Sweden)

    Hasheminya SM

    2006-01-01

    Full Text Available Background and Aim: Care must be taken during root canal therapy to prevent contamination of filling materials and avoid root canal contamination. Gutta-percha cones are now widely used to fill root canals. However they are not resistant to conventional sterilization processes in moist or dry heat. To keep the aseptic chain, gutta-percha cones require rapid chair side decontamination before use. Considering different methods for rapid decontamination of gutta-percha cones, use of chemical agents is the best. The purpose of this study was to compare the effectiveness of three different disinfectant solutions in rapid decontamination of gutta-percha cones in one minute Materials and Methods: In this experimental study, 360 gutta-percha cones were placed in bacterial suspensions of Staphylococcus aurous, Escherichia coli and Bacillus subtilis spore for 30 minutes, and then immersed in disinfectant solutions (Micro-10, Deconex 53 Plus, 5.25% sodium hypocholorite for 1 minute. After that, the cones were aseptically transferred to the test tubes containing sterile saline. This solution was diluted 10-fold and then cultured on in brain-heart-infusion agar and the number of colonies was estimated after 24 h incubation at 37ْC. A series of 5 previously sterilized cones was used as negative control to check the sterility of gutta-percha cones directly from the manufacturer's box. Another series of gutta-percha cones were considered as positive control group. Results: No bacterial growth was seen in different test groups and negative control group. Conclusion: Analysis of disinfectant effects of sodium hypochlorite, Micro10 and Deconex 53 plus showed that all of these solutions have bactericidal and sporocidal effect and are very efficient in surface disinfection of gutta–percha cones in one minute. Because of irritative effects and unpleasant odor of sodium hypochlorite, Deconex 53 plus and Micro10 can be used for rapid decontamination of gutta

  10. Formulation of a mathematical model to predict solar water disinfection.

    Science.gov (United States)

    Salih, Fadhil M

    2003-09-01

    A mathematical model was formulated that will facilitate the prediction of solar disinfection by analyzing the effect of sunlight exposure (x(1)) and the load of bacterial contamination (x(2)), as predictor variables, on the efficiency of solar disinfection (y). Aliquots of 0.1 ml containing average numbers of E. coli, ranging between 1 and 5 x 10(3)cells/ml raw water, were introduced into each of the 96 wells of polystyrene microtitre plates. Plates, with the lid on, were exposed to sunlight for varying exposures ranging between 1.04 x 10(3) and 8.40 x 10(3)kJ m(-2). Double strength nutrient broth was then added. After 48 h incubation wells containing visible contamination were considered as containing one cell or more that survived the exposure. Data showed that disinfection is dependent both on the load of bacterial contamination and sunlight exposure. This relationship is characterized by curves having shoulders followed by a steep decline and then tailing off in an asymptotic fashion. The shoulder size increased with the increase of the contamination load, however, the slope remains the same. Statistical analysis indicates a positive correlation among the variables (R(2) = 0.893); the mathematical model, y=1-(1-e(-kx(1)))(x(2)), represents the relationship, with k being the solar inactivation constant. The exposure required to produce a given decontamination level can be predicted using the equation: x(1)=-1/kln[1-(1-y)(-1/x(2))]e(-micro/rho.m/A), where micro is the linear attenuation coefficient (m(-1)), rho is the density, m is the mass and A is the area of the exposed part of the sample. The predictor variables (x(1), x(2)) strongly influence the efficiency of solar disinfection, which can be predicted using the suggested mathematical model. The present data provides a means to predict the efficiency of solar disinfection as an approach to improve the quality of drinking water mainly in developing countries with adequate sunshine all year-round.

  11. Bacterial resistance to Quaternary Ammonium Compounds (QAC) disinfectants.

    Science.gov (United States)

    Bragg, Robert; Jansen, Arina; Coetzee, Marisa; van der Westhuizen, Wouter; Boucher, Charlotte

    2014-01-01

    Control of bacterial diseases has, for many years, been dependent on the use of antibiotics. Due to the high levels of efficacy of antibiotics in the past other disease control options have, to a large extent, been neglected. Mankind is now facing an increasing problem with antibiotic resistance. In an effort to retain some antibiotics for human use, there are moves afoot to limit or even ban the use of antibiotics in animal production. The use of antibiotics as growth promoters have been banned in the European Union and the USA. The potential ban on the use of antibiotics to treat diseases in production animals creates a dilemma for man-suffer significant problem with bacterial infection or suffer from a severe shortage of food! There are other options for the control of bacterial diseases. These include vaccine development, bacteriophage therapy, and improved biosecurity. Vaccine development against bacterial pathogens, particularly opportunistic pathogens, is often very challenging, as in many cases the molecular basis of the virulence is not always clearly understood. This is particularly true for Escherichia coli. Biosecurity (disinfection) has been a highly neglected area in disease control. With the ever-increasing problems with antibiotic resistance-the focus should return to improvements in biosecurity. As with antibiotics, bacteria also have mechanisms for resistance to disinfectants. To ensure that we do not replace one set of problems (increasing antibiotic resistance) with another (increasing resistance to disinfectants) we need to fully understand the modes of action of disinfectants and how the bacteria develop resistance to these disinfectants. Molecular studies have been undertaken to relate the presence of QAC resistance genes in bacteria to their levels of sensitivity to different generations of QAC-based products. The mode of action of QAC on bacteria has been studied using NanoSAM technology, where it was revealed that the QAC causes disruption

  12. Fibrous Catalyst-Enhanced Acanthamoeba Disinfection by Hydrogen Peroxide.

    Science.gov (United States)

    Kilvington, Simon; Winterton, Lynn

    2017-11-01

    Hydrogen peroxide (H2O2) disinfection systems are contact-lens-patient problem solvers. The current one-step, criterion-standard version has been widely used since the mid-1980s, without any significant improvement. This work identifies a potential next-generation, one-step H2O2, not based on the solution formulation but rather on a case-based peroxide catalyst. One-step H2O2 systems are widely used for contact lens disinfection. However, antimicrobial efficacy can be limited because of the rapid neutralization of the peroxide from the catalytic component of the systems. We studied whether the addition of an iron-containing catalyst bound to a nonfunctional propylene:polyacryonitrile fabric matrix could enhance the antimicrobial efficacy of these one-step H2O2 systems. Bausch + Lomb PeroxiClear and AOSept Plus (both based on 3% H2O2 with a platinum-neutralizing disc) were the test systems. These were tested with and without the presence of the catalyst fabric using Acanthamoeba cysts as the challenge organism. After 6 hours' disinfection, the number of viable cysts was determined. In other studies, the experiments were also conducted with biofilm formed by Stenotrophomonas maltophilia and Elizabethkingia meningoseptica bacteria. Both control systems gave approximately 1-log10 kill of Acanthamoeba cysts compared with 3.0-log10 kill in the presence of the catalyst (P catalyst compared with ≥3.0-log10 kill when it was omitted. In 30 rounds' recurrent usage, the experiments, in which the AOSept Plus system was subjected to 30 rounds of H2O2 neutralization with or without the presence of catalytic fabric, showed no loss in enhanced biocidal efficacy of the material. The catalytic fabric was also shown to not retard or increase the rate of H2O2 neutralization. We have demonstrated the catalyst significantly increases the efficacy of one-step H2O2 disinfection systems using highly resistant Acanthamoeba cysts and bacterial biofilm. Incorporating the catalyst into the

  13. Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test.

    Science.gov (United States)

    Nie, Xuebiao; Liu, Wenjun; Zhang, Liping; Liu, Qing

    2017-06-01

    The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV+chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl 2 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks. Copyright © 2016. Published by Elsevier B.V.

  14. Eggcrate UV: a whole ceiling upper-room ultraviolet germicidal irradiation system for air disinfection in occupied rooms.

    Science.gov (United States)

    Linnes, J C; Rudnick, S N; Hunt, G M; McDevitt, J J; Nardell, E A

    2014-04-01

    A novel whole ceiling upper-room ultraviolet germicidal irradiation (UVGI) system [eggcrate ultraviolet (UV)] has been developed that incorporates open-cell 'eggcrate'-suspended ceiling panels and bare UV lamps with a ceiling fan. Upper-room UVGI is more effective for air disinfection than mechanical ventilation at much lower installation and operating costs. Conventional upper-room UVGI fixtures employ multiple tightly spaced horizontal louvers to confine UV to the upper-room. These louvered fixtures protect occupants in the lower-room from UV-induced eye and skin irritation, but at a major cost to fixture efficiency. Using a lamp and ballast from a conventional upper-room UVGI fixture in the eggcrate UV system, the germicidal efficacy was markedly improved even though the UV radiation emitted by the lamp was unchanged. This fundamental change in the application of upper-room UVGI air disinfection should permit wider, more effective application of UVGI globally to reduce the spread of airborne infection. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Solar light (hv) and H2O2/hv photo-disinfection of natural alkaline water (pH 8.6) in a compound parabolic collector at different day periods in Sahelian region.

    Science.gov (United States)

    Ndounla, J; Pulgarin, C

    2015-11-01

    The photo-disinfection of natural alkaline surface water (pH 8.6 ± 0.3) for drinking purposes was carried out under solar radiation treatments. The enteric bacteria studied were the wild total coliforms/Escherichia coli (10(4) CFU/ml) and Salmonella spp. (10(4) CFU/ml) naturally present in the water. The photo-disinfection of a 25-l water sample was carried out in a solar compound parabolic collector (CPC) in the absence and in the presence of hydrogen peroxide (H2O2). The addition of H2O2 (10 mg/L) to the sample water was sufficient to enhance the photo-disinfection and ensure an irreversible lethal action on the wild enteric bacteria contents of the sample. The inactivation kinetic of the system was significantly enhanced compared to the one carried out without H2O2 addition. The effect of the solar radiation parameters on the efficiency of the photo-disinfection were assessed. The pH has increased during the treatment in all the photo-disinfection processes (hv and H2O2/hv). The Salmonella spp strain has shown the best effective inactivate time in alkaline water than the one recorded under acidic or near-neutral conditions. The evolution of some physico-chemical parameters of the water (turbidity, NO2(-), NO3(-), NH4(+), HPO4(2-), and bicarbonate (HCO3(-))) was monitored during the treatment. Finally, the possible mechanistic process involved during the enteric bacteria inactivation was suggested.

  16. Selection of a Biosafety Level 1 (BSL-1 surrogate to evaluate surface disinfection efficacy in Ebola outbreaks: Comparison of four bacteriophages.

    Directory of Open Access Journals (Sweden)

    Karin Gallandat

    Full Text Available The 2014 West African Ebola virus disease outbreak was the largest to date, and conflicting, chlorine-based surface disinfection protocols to interrupt disease transmission were recommended. We identified only one study documenting surface disinfection efficacy against the Ebola virus, showing a >6.6 log reduction after 5-minute exposure to 0.5% sodium hypochlorite (NaOCl based on small-scale tests (Cook et al. (2015. In preparation for future extensive, large-scale disinfection efficacy experiments, we replicated the Cook et al. experiment using four potential BSL-1 surrogates selected based on similarities to the Ebola virus: bacteriophages MS2, M13, Phi6, and PR772. Each bacteriophage was exposed to 0.1% and 0.5% NaOCl for 1, 5, and 10 minutes on stainless steel. MS2 and M13 were only reduced by 3.4 log and 3.5 log after a 10-minute exposure to 0.5% NaOCl, and would be overly conservative surrogates. Conversely, PR772 was too easily inactivated for surrogate use, as it was reduced by >4.8 log after only 1-minute exposure to 0.5% NaOCl. Phi6 was slightly more resistant than the Ebola virus, with 4.1 log reduction after a 5-minute exposure and not detected after a 10-minute exposure to 0.5% NaOCl. We therefore recommend Phi6 as a surrogate for evaluating the efficacy of chlorine-based surface disinfectants against the Ebola virus.

  17. Physics for radiation protection

    CERN Document Server

    Martin, James E

    2013-01-01

    A much-needed working resource for health physicists and other radiation protection professionals, this volume presents clear, thorough, up-to-date explanations of the basic physics necessary to address real-world problems in radiation protection. Designed for readers with limited as well as basic science backgrounds, Physics for Radiation Protection emphasizes applied concepts and carefully illustrates all topics through examples as well as practice problems. Physics for Radiation Protection draws substantially on current resource data available for health physics use, providing decay schemes and emission energies for approximately 100 of the most common radionuclides encountered by practitioners. Excerpts of the Chart of the Nuclides, activation cross sections, fission yields, fission-product chains, photon attenuation coefficients, and nuclear masses are also provided.

  18. Status of the effectiveness of contact lens disinfectants in Malaysia against keratitis-causing pathogens.

    Science.gov (United States)

    Abjani, Farhat; Khan, Naveed Ahmed; Jung, Suk Yul; Siddiqui, Ruqaiyyah

    2017-09-15

    The aim of this study was (i) to assess the antimicrobial effects of contact lens disinfecting solutions marketed in Malaysia against common bacterial eye pathogens and as well as eye parasite, Acanthamoeba castellanii, and (ii) to determine whether targeting cyst wall would improve the efficacy of contact lens disinfectants. Using ISO 14729 Stand-Alone Test for disinfecting solutions, bactericidal and amoebicidal assays of six different contact lens solutions including Oxysept(®), AO SEPT PLUS, OPTI-FREE(®) pure moist(®), Renu(®) fresh™, FreshKon(®) CLEAR and COMPLETE RevitaLens™ were performed using Manufacturers Minimum recommended disinfection time (MRDT). The efficacy of contact lens solutions was determined against keratitis-causing microbes, namely: Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Acanthamoeba castellanii. In addition, using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, we determined whether combination of both agents can enhance efficacy of marketed contact lens disinfectants against A. castellanii trophozoites and cysts, in vitro. The results revealed that all contact lens disinfectants tested showed potent bactericidal effects exhibiting 100% kill against all bacterial species tested. In contrast, none of the contact lens disinfectants had potent effects against Acanthamoeba cysts viability. When tested against trophozoites, two disinfectants, Oxysept Multipurpose and AO-sept Multipurpose showed partial amoebicidal effects. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents in contact lens disinfectants abolished viability of A. castellanii cysts and trophozoites. Given the inefficacy of contact lens disinfectants tested in this study, these findings present a significant concern to public health. These

  19. Efficacy of computer-based endoscope cleaning and disinfection using a hospital management information system.

    Science.gov (United States)

    Wang, Caixia; Chen, Yuanyuan; Yang, Feng; Ren, Jie; Yu, Xin; Wang, Jiani; Sun, Siyu

    2016-08-01

    The present study aimed to assess the efficacy of computer-based endoscope cleaning and disinfection using a hospital management information system (HMIS). A total of 2,674 gastroscopes were eligible for inclusion in this study. For the processes of disinfection management, the gastroscopes were randomly divided into 2 groups: gastroscope disinfection HMIS (GD-HMIS) group and manual group. In the GD-HMIS group, an integrated circuit card (IC card) chip was installed to monitor and record endoscope cleaning and disinfection automatically and in real time, whereas the endoscope cleaning and disinfection in the manual group was recorded manually. The overall disinfection progresses for both groups were recorded, and the total operational time was calculated. For the GD-HMIS group, endoscope disinfection HMIS software was successfully developed. The time to complete a single session of cleaning and disinfecting on a gastroscope was 15.6 minutes (range, 14.3-17.2 minutes) for the GD-HMIS group and 21.3 minutes (range, 20.2-23.9 minutes) for the manual group. Failure to record information, such as the identification number of the endoscope, occasionally occurred in the manual group, which affected the accuracy and reliability of manual recording. Computer-based gastroscope cleaning and disinfection using a hospital management information system could monitor the process of gastroscope cleaning and disinfection in real time and improve the accuracy and reliability, thereby ensuring the quality of gastroscope cleaning and disinfection. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  20. Evaluation of possible use of disinfectant based on chlorine dioxide in dairy plant

    Directory of Open Access Journals (Sweden)

    Rakić-Martinez Mira

    2009-01-01

    Full Text Available Poor sanitation of food contact surfaces has been a contributing factor in food borne disease outbreaks, especially those involving Listeria monocytogenes, Salmonella spp., Escherichia coli, Staphylococcus aureus etc. The objectives of this study were therefore to: 1. Determine the efficiency of a disinfectant based on chlorine dioxide in suspension in a closed system in a dairy plant. 2. Evaluate the possibility of disinfection of working surfaces with a disinfectant based on chlorine dioxide. In order to determine the germicidal effect of the disinfectant based on chlorine dioxide by suspension test (BSEN 1276:1997; the following test organisms were used: Listeria monocytogenes, Proteus mirabilis, Escherichia coli, Bacillus cereus, Staphylococcus aureus and Pseudomonas aeruginosa clinical isolate. The corrosive properties of the disinfectant based on chlorine dioxide were tested by IDF 077:1977 standard. The efficacy of this disinfectant was investigated in a closed system in a dairy plant. Results indicated a 100% reduction of >108 cfu/ml L. monocytogenes, E. coli, Proteus mirabilis, Pseudomonas aeruginosa, S. aureus, viable count after 1 minute of exposure to 100 ppm of the disinfectant based on chlorine dioxide and 400 ppm for Bacillus cereus. In the presence of 2% skim milk and 4 % skim milk concentrations of 200 and 250 ppm resulted in 100% reduction in numbers of the five of six test microorganisms, respectively. The spore former, Bacillus cereus is less susceptible to the disinfectant. Therefore, the efficient concentration for 100% reduction in viable count after 1 minute exposure was 500 ppm. The corrosive properties of the disinfectant were not determined. In the case of closed system disinfection in a dairy plant, reduction in viable count after 15 minute exposure to 100 ppm of disinfectant based on chlorine dioxide ranged from 80 to 100%.

  1. Date stones in broiler's feeding

    Directory of Open Access Journals (Sweden)

    Gualtieri, M.

    1990-01-01

    Full Text Available To evaluate date stones as dietary component for broilers, two trials were carried out. In the first trial, Tunisian Deglet date stones were used and in the second one, stones were the waste product of an Italian distillery. One-day-old Arbor Acres chickens were cage reared and fed for 6 weeks on 4 experimental diets, which were formulated to be isonitrogenous and isocaloric and differed in cereal component (maize or low tannin sorghum and in inclusion level (0 or 10 % of ground date stones. Birds ' performances were slightly different in the two trials, but overall results indicate that date stones are suitable for use in broiler's feeding under such conditions.

  2. Radiation Therapy

    Science.gov (United States)

    Radiation therapy is a cancer treatment. It uses high doses of radiation to kill cancer cells and stop them from ... half of all cancer patients receive it. The radiation may be external, from special machines, or internal, ...

  3. Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

    NARCIS (Netherlands)

    Kenters, N.; Huijskens, E.G.; Wit, S.C.J. de; Sanders, I.; Rosmalen, J. van; Kuijper, E.J.; Voss, A.

    2017-01-01

    BACKGROUND: In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested for their

  4. Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

    NARCIS (Netherlands)

    Kenters, N.; E. Huijskens (Elisabeth); de Wit, S.C.J.; Sanders, I.G.J.M.; J.M. van Rosmalen (Joost); E. Kuijper; Voss, A.

    2017-01-01

    textabstractBackground: In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested

  5. The synergistic effect of Escherichia coli inactivation by sequential disinfection with low level chlorine dioxide followed by free chlorine.

    Science.gov (United States)

    Yang, Wu; Yang, Dong; Zhu, Sui-Yi; Chen, Bo-Yan; Huo, Ming-Xin; Li, Jun-Wen

    2012-12-01

    To the best of our knowledge, there was little information available on pathogen removal using low level disinfectant followed by free chlorine in sequential disinfection (SD). This study investigated Escherichia coli inactivation by four types of disinfection: single step disinfection (SSD), SD, traditional sequential disinfection (TSD) and mixed disinfectant disinfection (MDD). Results indicated that SD had higher ability to inactivate E. coli than the others, indicating there was a positive synergistic effect on chlorine disinfection by prior dosing with a low level of chlorine dioxide (ClO(2)). The ONPG assay suggested that the permeability of cell wall rather than the viability of E. coli were changed under 0.02 mg/l ClO(2) treatment. The coexistence of residual ClO(2) and free chlorine also plays an active synergistic effect. Additionally, temperature had a positive effect on E. coli inactivation in SD, while inactivation was reduced in alkaline compared to neutral and acidic conditions.

  6. A procedure for disinfecting Atlantic salmon (Salmo salar) eggs using a polyvinylpyrrolidone-iodine (PVP-I) solution

    National Research Council Canada - National Science Library

    Frantsi, C; Withey, K.G

    1972-01-01

    .... The procedure involves complete disinfection of incubation facilities, hardening, measuring, picking of dead eggs, and disinfection of eggs for 10 minutes in a solution of polyvinylpyrrolidone-iodine (PVP...

  7. Microscale radiocarbon dating of paintings

    Energy Technology Data Exchange (ETDEWEB)

    Hendriks, Laura; Hajdas, Irka; McIntyre, Cameron [ETH Zurich, Ion Beam Physics, Zurich (Switzerland); Kueffner, Markus; Ferreira, Ester S.B. [SIK-ISEA, Zurich, Zurich (Switzerland); Scherrer, Nadim C. [Bern University of Applied Sciences, HKB, Bern (Switzerland)

    2016-03-15

    In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. {sup 14}C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, provided the opportunity to evaluate the dating accuracy on paintings realized before and after 1950 AD when the {sup 14}C bomb peak was created, as a result of the nuclear tests conducted in the 1950/1960s. The work focused on the one hand on minimizing the size of the canvas sample required for accelerator mass spectrometer radiocarbon measurement on the gas ion source of the MICADAS and, on the other hand, on testing the possibility of dating the organic binder of the paint. Following careful characterization of the paint composition by X-ray fluorescence spectroscopy, Fourier transformed infrared spectroscopy, and Raman spectroscopy, paints containing no other carbon source than the natural organic binder were identified and dated. (orig.)

  8. Radiocarbon dating of iron artefacts

    Energy Technology Data Exchange (ETDEWEB)

    Cresswell, R. [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics

    1997-12-31

    Iron artefacts are generally dated by association or on stylistic grounds. This may not give a true indication of the date of manufacture, or may not be possible if the piece is out of context, ambiguous in style, or a copy. Obtaining a direct date on the artefact would be preferable. During the processes of manufacture, carbon is incorporated into the iron from the fuel source. If the fuel is of a material containing contemporaneous carbon, i.e. has an ambient radiocarbon signature, e.g. charcoal, then we may reliably radiocarbon date the artefact by extracting this carbon. Care must be taken, however, to ensure that re-working has not introduced multiple sources of carbon that would give an erroneous date. Detailed chemical analysis must precede radiocarbon analysis. Sample size is determined by carbon content, and before the advent of accelerator mass spectrometry, several tens of grams of carbon were required for radiocarbon dating (van der Merwe, 1969), prohibiting this method except for high-carbon cast-irons and bulk samples, e.g. caches of nails. AMS permits the analysis of sub-gram pieces of iron (Cresswell, 1991), thereby permitting the analysis of museum pieces with only minimal loss of material, and small fragments of iron recovered from archaeological sites. A few examples are given to illustrate these points. Paper no. 41; Extended abstract. 6 refs.

  9. Dating

    African Journals Online (AJOL)

    Among its other ills, the Internet has widened children's access to pornography with its estimated over 28,000 sex-oriented and porn sites on the www; child moles- tation (Ota, 1997:3029); promoted gambling (New York Times, 199718;. Gruenwald, l998az238); encouraged terrorism with the influx of uncensored ...

  10. Radiation dosimetry

    CERN Document Server

    Hine, Gerald J; Hine, Gerald J

    1956-01-01

    Radiation Dosimetry focuses on the advancements, processes, technologies, techniques, and principles involved in radiation dosimetry, including counters and calibration and standardization techniques. The selection first offers information on radiation units and the theory of ionization dosimetry and interaction of radiation with matter. Topics include quantities derivable from roentgens, determination of dose in roentgens, ionization dosimetry of high-energy photons and corpuscular radiations, and heavy charged particles. The text then examines the biological and medical effects of radiation,

  11. Inactivation of single-celled Ascaris suum eggs by low-pressure UV radiation.

    Science.gov (United States)

    Brownell, Sarah A; Nelson, Kara L

    2006-03-01

    Intact and decorticated single-celled Ascaris suum eggs were exposed to UV radiation from low-pressure, germicidal lamps at fluences (doses) ranging from 0 to 8,000 J/m2 for intact eggs and from 0 to 500 J/m2 for decorticated eggs. With a UV fluence of 500 J/m2, 0.44-+/-0.20-log inactivation (mean+/-95% confidence interval) (63.7%) of intact eggs was observed, while a fluence of 4,000 J/m2 resulted in 2.23-+/-0.49-log inactivation (99.4%). (The maximum quantifiable inactivation was 2.5 log units.) Thus, according to the methods used here, Ascaris eggs are the most UV-resistant water-related pathogen identified to date. For the range of fluences recommended for disinfecting drinking water and wastewater (200 to 2,000 J/m2), from 0- to 1.5-log inactivation can be expected, although at typical fluences (less than 1,000 J/m2), the inactivation may be less than 1 log. When the eggs were decorticated (the outer egg shell layers were removed with sodium hypochlorite, leaving only the lipoprotein ascaroside layer) before exposure to UV, 1.80-+/-0.32-log reduction (98.4%) was achieved with a fluence of 500 J/m2, suggesting that the outer eggshell layers protected A. suum eggs from inactivation by UV radiation. This protection may have been due to UV absorption by proteins in the outer layers of the 3- to 4-microm-thick eggshell. Stirring alone (without UV exposure) also inactivated some of the Ascaris eggs (approximately 20% after 75 min), which complicated determination of the inactivation caused by UV radiation alone.

  12. Lens material and formulation of multipurpose solutions affects contact lens disinfection.

    Science.gov (United States)

    Santos, Lívia; Oliveira, Rosário; Oliveira, M Elisabete C D Real; Azeredo, Joana

    2011-08-01

    To assess the disinfection efficacy of multipurpose solutions (MPS) against different bacterial species adhered either to silicon hydrogel or to conventional hydrogel contact lenses (CLs). The influences of the MPS formulation and the chemical composition of the lens material were investigated. This investigation followed the standard 14729, which establishes the guidelines for assessing CL disinfecting solutions. Two commercially available (Opti-Free(®) Express(®) and Renu(®) Multiplus) solutions and one recalled solution (Complete(®) MoisturePlus™) were used in this study. After disinfection, the number of survivors was estimated by the colony forming units' method. The lens material appears to influence disinfection. The conventional hydrogel polymacon exhibited the highest disinfection scores, a fact that should be related with the lack of electrostatic attraction towards the biocides and its hydrophilicity. The MPS formulation appears to have influence in disinfection efficacy as well. For most adhered bacteria, Opti-Free(®) was capable of reducing cell concentration in 4-log. Disinfection results from multivariate factors and this study confirmed that the lens material and the MPS play a very important role in the disinfection efficacy of CL. Copyright © 2011. Published by Elsevier Ltd.

  13. Knowledge and behavior of dentists in a dental school regarding toothbrush disinfection

    Directory of Open Access Journals (Sweden)

    Ilkay PEKER

    2015-01-01

    Full Text Available The aim of this study was to evaluate the knowledge and behavior of dentists regarding toothbrush disinfection. This study included 147 dentists (88 women and 59 men who were actively employed at a dental school in Ankara, Turkey. Participants were asked to fill out a standard questionnaire, which contained questions regarding their demographics, brushing habits, toothbrush storage and disinfection habits, toothpaste use, knowledge about toothbrush disinfection, and whether they advised their patients about toothbrush storage. Descriptive statistics were calculated, and statistical analyses were performed with t-tests, chi-squared tests, and Fisher exact tests, where appropriate. Among the 147 surveyed dentists, 62.6% and 85.7% reported that they did not have any knowledge about toothbrush disinfection and did not disinfect their toothbrushes, respectively. However, approximately two thirds of surveyed dentists thought that toothbrush disinfection should be performed by everyone, including healthy individuals. Significant associations were found between knowledge about toothbrush disinfection and the professional title of dentists, how they stored their toothbrushes, and whether their toothbrushes were in contact with each other during storage (p < 0.05. A minority of dentists reported that they disinfected their toothbrushes.

  14. Chloraminated Concentrated Drinking Water for Disinfection Byproduct Mixtures Research: Evaluating Free Chlorine Contact Times

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) present in the source water. Since 1974, over 600 DBPs have been identified in drinking water, yet a large portio...

  15. Chloramination of Concentrated Drinking Water: Evaluation of Disinfection Byproduct Formation and Dosing Scenarios - Portland

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

  16. Surface detail reproduction and dimensional accuracy of molds: influence of disinfectant solutions and elastomeric impression materials.

    Science.gov (United States)

    Guiraldo, Ricardo D; Berger, Sandrine B; Siqueira, Ronaldo Mt; Grandi, Victor H; Lopes, Murilo B; Gonini-Júnior, Alcides; Caixeta, Rodrigo V; de Carvalho, Rodrigo V; Sinhoreti, Mário Ac

    2017-04-01

    This study compared the surface detail reproduction and dimensional accuracy of molds after disinfection using 2% sodium hypochlorite, 2% chlorhexidine digluconate or 0.2% peracetic acid to those of molds that were not disinfected, for four elastomeric impression materials: polysulfide (Light Bodied Permlastic), polyether (Impregum Soft), polydimethylsiloxane (Oranwash L) andpolyvinylsiloxane (Aquasil Ultra LV). The molds were prepared on a matrix by applying pressure, using a perforated metal tray. The molds were removed following polymerization and either disinfected (by soaking in one of the solutions for 15 minutes) or not disinfected. The samples were thus divided into 16 groups (n=5). Surface detail reproduction and dimensional accuracy were evaluated using optical microscopy to assess the 20-μm line over its entire 25 mm length. The dimensional accuracy results (%) were subjected to analysis of variance (ANOVA) and the means were compared by Tukey's test (a=5%). The 20-μm line was completely reproduced by all elastomeric impression materials, regardless of disinfection procedure. There was no significant difference between the control group and molds disinfected with peracetic acid for the elastomeric materials Impregum Soft (polyether) and Aquasil Ultra LV (polyvinylsiloxane). The high-level disinfectant peracetic acid would be the choice material for disinfection. Sociedad Argentina de Investigación Odontológica.

  17. The effect of disinfectant agents in eliminating the contamination of dental unit water

    NARCIS (Netherlands)

    Ozcan, M; Kulak, Y; Kazazoglu, E

    High concentrations of water-borne organisms cause multiple public health problems. Contamination of water exiting the dental unit water lines could be inhibited with the use of some disinfectants. The purpose of this investigation was to establish the effect of two disinfectants and to test their

  18. Development of a Standard Test to Assess the Resistance of Staphylococcus aureus Biofilm Cells to Disinfectants

    NARCIS (Netherlands)

    Luppens, S.B.I.; Reij, M.W.; Heijden, van der R.W.; Rombouts, F.M.; Abee, T.

    2002-01-01

    A standardized disinfectant test for Staphylococcus aureus cells in biofilms was developed. Two disinfectants, the membrane-active compound benzalkonium chloride (BAC) and the oxidizing agent sodium hypochlorite, were used to evaluate the biofilm test. S. aureus formed biofilms on glass, stainless

  19. Reducing viral contamination from finger pads: handwashing is more effective than alcohol-based hand disinfectants

    NARCIS (Netherlands)

    Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Duizer, E.

    2015-01-01

    Background - Hand hygiene is important for interrupting transmission of viruses through hands. Effectiveness of alcohol-based hand disinfectant has been shown for bacteria but their effectiveness in reducing transmission of viruses is ambiguous. Aim - To test efficacy of alcohol hand disinfectant

  20. [Microbiological assesssment of efficiency chemothermal disinfection of blood contaminated hospital textiles].

    Science.gov (United States)

    Röhm-Rodowald, Ewa; Jakimiak, Bozenna; Podgórska, Marta; Chojecka, Agnieszka

    2010-01-01

    Thermal disinfection should be applied to laundering procedures of hospital textiles contaminated with blood. Currently, there is an increasing number of hospital textiles composed of cotton-polyester blends that cannot endure high temperatures of thermal disinfection. Besides, decreasing the temperature of chemothermal disinfection enhances the possibility of micro-organisms to survive the laundering procedure. The aim of this study was to prepare a new method for the microbiological evaluation of disinfecting laundering procedures for hospital textiles contaminated with blood. The bactericidal activity of chemical disinfectants for chemothermal disinfection was determined by simulating a laundering procedure for hospital textiles in the laboratory according to procedure of National Institute of Hygiene - DF/05/03. Bioindicators cotton carriers inoculated with Enterococcus faecium were used for determinating the antibacterial effects for hospital textiles contaminated with blood. High concentrations of bovine albumin and/or sheep erythrocytes were used as substrate for simulating human blood. The results showed that the bactericidal activity of chemical disinfectants for chemothermal disinfection hospital textiles in the event of massive organic contamination--heavily soiled with blood, shall be evaluated using carrier test in following conditions: test organism- Enterococcus faecium, interfering substances--6 g/l bovine albumin solution added to preparation.

  1. Comparative transcriptomic and phenotypic analysis of the responses of Bacillus cereus to various disinfectant treatments

    NARCIS (Netherlands)

    Ceragioli, M.; Mols, J.M.; Moezelaar, R.; Ghelardi, E.; Senesi, S.; Abee, T.

    2010-01-01

    Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of Bacillus cereus ATCC 14579 exposed to four

  2. 9 CFR 71.12 - Sodium orthophenylphenate as permitted disinfectant for premises infected with tuberculosis.

    Science.gov (United States)

    2010-01-01

    ... disinfectant for premises infected with tuberculosis. 71.12 Section 71.12 Animals and Animal Products ANIMAL... disinfectant for premises infected with tuberculosis. (a) A permitted brand of sodium orthophenylphenate in a proportion of at least one pound to 12 gallons of water is permitted in tuberculosis eradication work for...

  3. Photocatalytic disinfection of spoilage bacteria Pseudomonas fluorescens and Macrococcus caseolyticus by nano-TiO2

    Science.gov (United States)

    Photocatalytic disinfection of spoilage bacteria gram-negative (G-) P. fluorescens and gram-positive (G+) M. caseolyticus by nano-TiO2 under different experimental conditions and the disinfection mechanism were investigated. The experimental conditions included the initial bacterial populations, nan...

  4. Influence of investment, disinfection, and storage on the microhardness of ocular resins.

    Science.gov (United States)

    Goiato, Marcelo Coelho; dos Santos, Daniela Micheline; Gennari-Filho, Humberto; Zavanelli, Adriana Cristina; Dekon, Stefan Fiuza de Carvalho; Mancuso, Daniela Nardi

    2009-01-01

    The longevity of an ocular prosthesis is directly related to the resistance to erosion of its material. The purpose of this study was to evaluate the effects of chemical disinfection and the method of investment on the microhardness of ocular prosthesis acrylic resin. Thirty-two test specimen investments were obtained in two silicones. A segment was cut in each test specimen, and each specimen was fixed in an acrylic disk. The specimens were then polished and submitted to the first microhardness test before immersion in distilled water and incubation for 2 months. During this 2-month period, the specimens were immersed in a water bath at 37 degrees C and were disinfected daily; half were disinfected with neutral soap and the other half were disinfected with 4% chlorhexidine gluconate. After the storage phase and disinfection, a second microhardness test was performed. The surface microhardness values for the acrylic resins were submitted to ANOVA, followed by the Tukey test. The disinfection and the period of storage did not statistically influence the surface microhardness of the acrylic resin, independent of the method of investment of the specimens (Zetalabor or Vipi Sil). The investment of specimens with Zetalabor silicone presented a greater surface hardness, independent of the type of disinfection and the period of storage. Based on these results, we suggest that the microhardness of the resin evaluated was not influenced by the method of disinfection or the time of storage used and was affected only by the investment material.

  5. A comparison of the efficacy of different disinfection methods in eliminating Salmonella contamination from turkey houses.

    Science.gov (United States)

    Mueller-Doblies, D; Carrique-Mas, J J; Sayers, A R; Davies, R H

    2010-08-01

    This study aimed to compare the efficacy of different disinfection methods in eliminating Salmonella contamination from turkey houses. Fifty depopulated turkey houses which had all housed Salmonella-positive flocks were visited after cleaning and disinfection. A minimum of 45 swab samples from different surfaces were taken per house and analysed for the presence of Salmonella. The sampled surfaces included intact floor surfaces, floor cracks, walls, feeders, drinkers, anteroom, nestboxes and miscellaneous items. Houses were grouped according to the disinfectant which had been used and the efficacy of the different groups of disinfectants was compared. Sixty-eight % of houses tested positive for Salmonella after C&D. Out of 4440 samples, 207 tested positive for Salmonella, giving an overall sample prevalence of 4.7%. There was no significant difference in the level of residual contamination between breeding, rearing and finishing houses. Products containing a mixture of formaldehyde, glutaraldehyde and quaternary ammonium compounds (QAC) performed significantly better than products containing hydrogen peroxide and peracetic acid. Cleaning and disinfection was least effective in nestboxes and anterooms. Thorough cleaning and the choice of a suitable disinfectant are crucial if Salmonella contamination of turkey houses is to be eliminated. This study shows that disinfectants containing a mixture of formaldehyde, glutaraldehyde and QAC perform significantly better under field conditions than oxidising products and should therefore be the first choice for disinfection of turkey premises where Salmonella is present.

  6. Chlorine cell disinfection determination with flow cell cytometry and plate count (poster)

    NARCIS (Netherlands)

    Peters, M.C.F.M.; Keuten, M.G.A.; De Kreuk, M.K.; Van Loosdrecht, M.C.M.; Rietveld, L.C.

    2013-01-01

    Chlorine is used for disinfection in different water systems. This research focuses on chlorine disinfection in swimming pool water. In the Netherlands, free available chlorine concentrations in swimming pools are limited between 0.5-1.5 mg/L, which is based on a 4-log removal of Pseudomonas

  7. Antimicrobial activity of home disinfectants and natural products against potential human pathogens.

    Science.gov (United States)

    Rutala, W A; Barbee, S L; Aguiar, N C; Sobsey, M D; Weber, D J

    2000-01-01

    To assess the efficacy of both natural products (vinegar, baking soda) and common commercial disinfectants (Vesphene IIse, TBQ, Clorox, Lysol Disinfectant Spray, Lysol Antibacterial Kitchen Cleaner, Mr. Clean Ultra, ethanol) designed for home or institutional use against potential human pathogens, including selected antibiotic-resistant bacteria. A quantitative suspension test was used to assess the efficacy of selected disinfectants following exposure times of 30 seconds and 5 minutes. Activity was assessed against Staphylococcus aureus, Salmonella choleraesuis, Escherichia coli O157:H7, and Pseudomonas aeruginosa. Selected disinfectants were also tested against poliovirus, vancomycin-susceptible and -resistant Enterococcus species, and methicillin-susceptible and -resistant S. aureus. The following compounds demonstrated excellent antimicrobial activity (>5.6-8.2 log10 reduction) at both exposure times: TBQ, Vesphene, Clorox, ethanol, and Lysol Antibacterial Kitchen Cleaner. Mr. Clean eliminated 4 to >6 logs10 and Lysol Disinfectant approximately 4 logs10 of pathogenic microorganisms at both exposure times. Vinegar eliminated baking soda 3 log10 reduction) against poliovirus. A variety of commercial household disinfectants were highly effective against potential bacterial pathogens. The natural products were less effective than commercial household disinfectants. Only Clorox and Lysol disinfectant were effective against poliovirus.

  8. Mycobactericidal activity of selected disinfectants using a quantitative suspension test.

    Science.gov (United States)

    Griffiths, P A; Babb, J R; Fraise, A P

    1999-02-01

    In this study, a quantitative suspension test carried out under both clean and dirty conditions was used to assess the activity of various instrument and environmental disinfectants against the type strain NCTC 946 and an endoscope washer disinfector isolate of Mycobacterium chelonae, Mycobacterium fortuitum NCTC 10,394, Mycobacterium tuberculosis H37 Rv NCTC 7416 and a clinical isolate of Mycobacterium avium-intracellulare (MAI). The disinfectants tested were; a chlorine releasing agent, sodium dichloroisocyanurate (NaDCC) at 1000 ppm and 10,000 ppm av Cl; chlorine dioxide at 1100 ppm av ClO2 (Tristel, MediChem International Limited); 70% industrial methylated spirits (IMS); 2% alkaline glutaraldehyde (Asep, Galan); 10% succinedialdehyde and formaldehyde mixture (Gigasept, Schulke & Mayr); 0.35% peracetic acid (NuCidex, Johnson & Johnson); and a peroxygen compound at 1% and 3% (Virkon, Antec International). Results showed that the clinical isolate of MAI was much more resistant than M. tuberculosis to all the disinfectants, while the type strains of M. chelonae and M. fortuitum were far more sensitive. The washer disinfector isolate of M. chelonae was extremely resistant to 2% alkaline activated glutaraldehyde and appeared to be slightly more resistant than the type strain to Nu-Cidex, Gigasept, Virkon and the lower concentration of NaDCC. This study has shown peracetic acid (Nu-Cidex), chlorine dioxide (Tristel), alcohol (IMS) and high concentrations of a chlorine releasing agent (NaDCC) are rapidly mycobactericidal. Glutaraldehyde, although effective, is a slow mycobactericide. Gigasept and Virkon are poor mycobactericidal agents and are not therefore recommended for instruments or spillage if mycobacteria are likely to be present.

  9. Is pomegranate peels infusion effective for disinfection of toothbrushes?

    Directory of Open Access Journals (Sweden)

    Priscila Lima de Luna FREIRE

    Full Text Available Abstract Introduction Methods of decontamination or sanitization of toothbrushes have been questioned. Objective This study assessed the effectiveness of pomegranate peels infusion as a disinfectant of toothbrushes against Streptococcus mutans. Material and method A sample of 16 schoolchildren aged between 7 and 9 years performed brushing 5 days/week, with a careful brushing once a day. After each day of brushing, the toothbrushes were washed and sprayed with one disinfectant solution. This procedure was repeated for 4 weeks using one of the different solutions per week: distilled water (G1; negative control, pomegranate (Punica granatum Linn peels infusion (G2, 1% sodium hypochlorite (G3 and 0.12% chlorhexidine digluconate (G4. After the fifth day, toothbrushes were collected for laboratory analysis. Toothbrushes heads were subjected to agitation in saline dilution of 10–1, 10–2,10–3, and 25 μL of each dilution were seeded in mitis salivarius agar culture medium for S. mutans colony-forming unit (CFU counting. One calibrated examiner (Kappa = 0.91 performed the CFU (mL–1 × 104 counts. Kruskal-Wallis and Dunn Multiple Comparison tests were used at a significance level of 5%. Result G1 presented the highest number of CFU (3.9 ± 8.4, followed by G2 (3.2 ± 4.0. No S. mutans growth was observed in G3 and G4. There was no statistically significant difference between G1 and G2 and between G3 and G4 (p>0.05. Conclusion Pomegranate infusion was completely ineffective for the disinfection of toothbrushes against S. mutans when compared with 1% sodium hypochlorite and 0.12% chlorhexidine digluconate solutions.

  10. Activity of disinfectants and biofilm production of Corynebacterium pseudotuberculosis

    Directory of Open Access Journals (Sweden)

    Maria da C.A. Sá

    2013-11-01

    Full Text Available To verify the occurrence of caseous lymphadenitis in sheep and goats on farms of Pernambuco, Brazil, and in animals slaughtered in two Brazilian cities (Petrolina/PE and Juazeiro/BA, and to characterize the susceptibility profile of Corynebacterium pseudotuberculosis to disinfectants and antimicrobials, and its relationship with biofilm production were the objectives of this study. 398 samples were tested for sensitivity to antimicrobial drugs, disinfectants, and biofilm production. Among the 108 samples collected on the properties, 75% were positive for C. pseudotuberculosis. Slaughterhouse samples indicated an occurrence of caseous lymphadenitis in 15.66% and 6.31% for animals slaughtered in Petrolina and Juazeiro respectively. With respect to antimicrobials, the sensitivity obtained was 100% for florfenicol and tetracycline; 99.25% for enrofloxacin, ciprofloxacin and lincomycin; 98.99% for cephalothin; 98.74% for norfloxacin and sulfazotrim; 97.74% for gentamicin; 94.22% for ampicillin; 91.71% for amoxicillin; 91.21% for penicillin G; 89.19% for neomycin and 0% for novobiocin. In analyzes with disinfectants, the efficiency for chlorhexidine was 100%, 97.20% for quaternary ammonium, 87.40% for chlorine and 84.40% for iodine. 75% of the isolates were weak or non-biofilm producers. For the consolidated biofilm, found that iodine decreased biofilm formation in 13 isolates and quaternary ammonia in 11 isolates. The reduction of the biofilm formation was observed for iodine and quaternary ammonium in consolidated biofilm formation in 33% and 28% of the isolates, respectively. The results of this study highlight the importance of establishing measures to prevent and control the disease.

  11. Efficacy and toxicity of iodine disinfection of Atlantic salmon eggs

    Science.gov (United States)

    Chalupnicki, M.A.; Ketola, H.G.; Starliper, C.E.; Gallagher, D.

    2011-01-01

    Recent interest in the restoration of Atlantic salmon Salmo salar in the Great Lakes has given rise to new culture techniques and management programs designed to reduce pathogen transmission while stabilizing and enhancing wild populations. We examined the toxicity of iodine to Atlantic salmon eggs and its effectiveness as a disinfectant against bacteria on egg surfaces. We spawned and fertilized eight gravid Atlantic salmon from Cayuga Lake, New York, and exposed their eggs to 10 concentrations of iodine (5, 10, 50, 75, 100, 500, 750, 1,000, 5,000, and 7,500 mg/L) for 30 min during water hardening. An additional subsample of unfertilized eggs was also exposed to some of the same concentrations of iodine (5, 10, 50, 75, and 100 mg/L) to determine the efficiency of disinfection. Viable eggs were only obtained from four females. Survival of eggs to the eyed stage and hatch tended to be reduced at iodine concentrations of 50 and 75 mg/L and was significantly reduced at concentrations of 100 mg/L iodine or more. We calculated the concentrations of iodine that killed 50% of the Atlantic salmon eggs at eye-up and hatch to be 175 and 85 mg/L, respectively. Aeromonas veronii, A. schubertii, A. hydrophila, A. caviae, Plesiomonas shiggeloides, and Citrobacter spp. were the predominant bacteria present on the surface of green eggs and were significantly reduced by an iodine immersion. The use of iodine as a disinfectant on Atlantic salmon eggs was effective at low concentrations (50–75 mg/L), for which toxicity to Atlantic salmon was minimal.

  12. Evaluation of a virucidal quantitative carrier test for surface disinfectants.

    Directory of Open Access Journals (Sweden)

    Holger F Rabenau

    Full Text Available Surface disinfectants are part of broader preventive strategies preventing the transmission of bacteria, fungi and viruses in medical institutions. To evaluate their virucidal efficacy, these products must be tested with appropriate model viruses with different physico-chemical properties under conditions representing practical application in hospitals. The aim of this study was to evaluate a quantitative carrier assay. Furthermore, different putative model viruses like adenovirus type 5 (AdV-5 and different animal parvoviruses were evaluated with respect to their tenacity and practicability in laboratory handling. To evaluate the robustness of the method, some of the viruses were tested in parallel in different laboratories in a multi-center study. Different biocides, which are common active ingredients of surface disinfectants, were used in the test. After drying on stainless steel discs as the carrier, model viruses were exposed to different concentrations of three alcohols, peracetic acid (PAA or glutaraldehyde (GDA, with a fixed exposure time of 5 minutes. Residual virus was determined after treatment by endpoint titration. All parvoviruses exhibited a similar stability with respect to GDA, while AdV-5 was more susceptible. For PAA, the porcine parvovirus was more sensitive than the other parvoviruses, and again, AdV-5 presented a higher susceptibility than the parvoviruses. All parvoviruses were resistant to alcohols, while AdV-5 was only stable when treated with 2-propanol. The analysis of the results of the multi-center study showed a high reproducibility of this test system. In conclusion, two viruses with different physico-chemical properties can be recommended as appropriate model viruses for the evaluation of the virucidal efficacy of surface disinfectants: AdV-5, which has a high clinical impact, and murine parvovirus (MVM with the highest practicability among the parvoviruses tested.

  13. UASB reactor effluent disinfection by ozone and chlorine.

    Science.gov (United States)

    Ribeiro da Silva, Gustavo Henrique; Bruning, Harry; Gerrity, Daniel; Daniel, Luiz Antonio

    2015-01-01

    This research studied the sequential ozone and chlorine process with respect to, the inactivation of indicator bacteria and the formation of ozone disinfection byproducts in sanitary wastewater effluent. The applied ozone doses were 5, 8 and 10 mg.O3.L(-1), followed by chlorine doses of 10, 20 and 30 mg.L(-1), respectively. After the sequential ozone/chlorine process, the mean reduction in chemical oxygen demand ranged from 9 to 37%. Total coliform inactivation ranged from 1.59 to 3.73 log10, and E. coli was always chlorine dose (P ≤ 0.05).

  14. Stability and effectiveness of chlorine disinfectants in water distribution systems.

    OpenAIRE

    Olivieri, V P; Snead, M C; Krusé, C W; Kawata, K

    1986-01-01

    A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic p...

  15. Combined Sewer Overflow pretreatment with chemical coagulation and a particle settler for improved peracetic acid disinfection

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Bonnerup, Arne; Andersen, Henrik Rasmus

    2016-01-01

    Full scale disinfection by peracetic acid (PAA) was achieved on Combined Sewer Overflow (CSO) water, which was pre-treated physically by a fast settling-filtration unit. Disinfection of untreated CSO water using PAA was compared to treatment using a particle separator (HydroSeparator®) and additi......Full scale disinfection by peracetic acid (PAA) was achieved on Combined Sewer Overflow (CSO) water, which was pre-treated physically by a fast settling-filtration unit. Disinfection of untreated CSO water using PAA was compared to treatment using a particle separator (Hydro......Separator®) and additional coagulation with poly-aluminum-chloride. Disinfection for Enterococcus increased with the applied dose of PAA and additional improvement was achieved when it was preceded by chemical coagulation with 5 mg L−1 poly-aluminum-chloride. When Enterococcus was reduced by treatment in the Hydro...

  16. Chemical disinfection of combined sewer overflow waters using performic acid or peracetic acids

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper

    2014-01-01

    We investigated the possibility of applying performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA towards Escherichia coli (E. coli) and Enterococcus was studied in batch......-scale and pre-field experiments. In the batch-scale experiment, 2.5 mg L− 1 PAA removed approximately 4 log unit of E. coli and Enterococcus from CSO with a 360 min contact time. The removal of E. coli and Enterococcus from CSO was always around or above 3 log units using 2–4 mg L− 1 PFA; with a 20 min contact...... time in both batch-scale and pre-field experiments. There was no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA; a slight toxic effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic...

  17. Dielectric Barrier Discharge based Mercury-free plasma UV-lamp for efficient water disinfection.

    Science.gov (United States)

    Prakash, Ram; Hossain, Afaque M; Pal, U N; Kumar, N; Khairnar, K; Mohan, M Krishna

    2017-12-12

    A structurally simple dielectric barrier discharge based mercury-free plasma UV-light source has been developed for efficient water disinfection. The source comprises of a dielectric barrier discharge arrangement between two co-axial quartz tubes with an optimized gas gap. The outer electrode is an aluminium baked foil tape arranged in a helical form with optimized pitch, while the inner electrode is a hollow aluminium metallic rod, hermetically sealed. Strong bands peaking at wavelengths 172 nm and 253 nm, along with a weak band peaking at wavelength 265 nm have been simultaneously observed due to plasma radiation from the admixture of xenon and iodine gases. The developed UV source has been used for bacterial deactivation studies using an experimental setup that is an equivalent of the conventional house-hold water purifier system. Deactivation studies for five types of bacteria, i.e., E. coli, Shigella boydii, Vibrio, Coliforms and Fecal coliform have been demonstrated with 4 log reductions in less than ten seconds.

  18. Excystation of Cryptosporidium parvum at temperatures that are reached during solar water disinfection.

    Science.gov (United States)

    Gómez-Couso, H; Fontán-Sainz, M; Fernández-Alonso, J; Ares-Mazás, E

    2009-04-01

    Species belonging to the genera Cryptosporidium are recognized as waterborne pathogens. Solar water disinfection (SODIS) is a simple method that involves the use of solar radiation to destroy pathogenic microorganisms that cause waterborne diseases. A notable increase in water temperature and the existence of a large number of empty or partially excysted (i.e. unviable) oocysts have been observed in previous SODIS studies with water experimentally contaminated with Cryptosporidium parvum oocysts under field conditions. The aim of the present study was to evaluate the effect of the temperatures that can be reached during exposure of water samples to natural sunlight (37-50 degrees C), on the excystation of C. parvum in the absence of other stimuli. In samples exposed to 40-48 degrees C, a gradual increase in the percentage of excystation was observed as the time of exposure increased and a maximum of 53.81% of excystation was obtained on exposure of the water to a temperature of 46 degrees C for 12 h (versus 8.80% initial isolate). Under such conditions, the oocyst infectivity evaluated in a neonatal murine model decreased statistically with respect to the initial isolate (19.38% versus 100%). The results demonstrate the important effect of the temperature on the excystation of C. parvum and therefore on its viability and infectivity.

  19. Solar disinfection for the post-treatment of greywater by means of a continuous flow reactor.

    Science.gov (United States)

    Pansonato, Natália; Afonso, Marcos V G; Salles, Carlos A; Boncz, Marc A; Paulo, Paula L

    2011-01-01

    SODIS (solar disinfection) is a low-cost alternative for water decontamination. The method is based on the exposure of water, contained in PET bottles, to direct sunlight, and mainly its UV-A and infrared components. The present research studied SODIS as a low cost alternative for the inactivation of Escherichia coli (E. coli) in treated greywater, aiming at its reuse for more noble applications. Experiments were performed in (i) batch mode (2 L PET-bottles), testing the effect of turbidity on system efficiency and, (ii) in a continuous pilot-scale reactor prototype (51 L, using interconnected 2 L-PET bottles), testing hydraulic retention times (HRT) of 18 and 24 h. Samples were exposed to an average solar radiation intensity of 518 W/m2. The results obtained indicate that the SODIS system has potential for total coliforms and E. coli inactivation in the pre-treated greywater, reaching 2.1 log units E. coli inactivation in batch experiments for low turbidity samples (21 NTU), and > 2 log units inactivation of total coliforms (and E. coli, when present) for the 24 h HRT-continuous prototype. The continuous flow prototype needs more testing and structural improvements to cope with the difficulties posed by algae growth, as they complicate maintaining conditions of constant flow and make frequent maintenance inevitable.

  20. Solar water disinfection (SODIS); Traitement de l'eau par l'energie solaire

    Energy Technology Data Exchange (ETDEWEB)

    Wegelin, M. [Water Treatment, EAWAG/SANDEC, Duebendorf (Switzerland)

    1998-07-01

    Solar water disinfection uses solar energy to inactivate and destroy pathogenic microorganisms present in the water. The use of solar energy, which is universally available and free of charge. is the basis of this low-cost technology to be applied on household level for the treatment of small quantifies of drinking water. The treatment basically consists in filling transparent containers with water and expose them to full sunlight for several hours. Extensive laboratory and field tests carried out by EAWAG and its partners revealed that synergies induced by the combined application of radiation and thermal treatment have a significant effect on the die-off rate of the microorganisms. For example, field tests demonstrated that the concentration of Vibrio cholerae is reduced by a factor of 1000 during an exposure time of 30 minutes and a water temperature of 50 deg.C. The use of half-side blackened bottles or of plastic bags is a simple application of the batch process which. however, limits the daily capacity to the volume of water stored in the containers. Continuous-flow systems consist of solar collectors and heat exchangers which significantly increase the use of the available solar energy and, thereby, also the output of treated water. (author)

  1. Kinetics of inactivation and photoreactivation of Escherichia coli using ultrasound-enhanced UV-C light-emitting diodes disinfection.

    Science.gov (United States)

    Zhou, Xiaoqin; Li, Zifu; Lan, Juanru; Yan, Yichang; Zhu, Nan

    2017-03-01

    Ultraviolet (UV) disinfection is highly recommended owing to its high disinfection efficiency and disinfection by-products free, and UV Light-Emitting Diodes (UV LEDs) is increasingly becoming an alternative of mercury UV lamps for water disinfection owing to its long lifetime, low input power, and absence of problems on disposal. However, renovation of existing UV lamps faces the challenges for UV disinfection associated with disinfection efficiency and photoreactivation, and modified UV disinfection process is required for practical application. In this study, mathematical rule of disinfection and photoreactivation in a US enhanced UV disinfection system was investigated. UV LED with peak emission at 254nm (UV-C LED) was selected as representative for UV lamps, and a low frequency US was used as pretreatment followed by UV disinfection. The disinfection efficiency of Escherichia coli in deionized water (DI), DI water with kaoline suspension (DIK), and secondary effluent (SE) of municipal wastewater treatment plant were analyzed. Moreover, photoreactivation of E. coli in DIK water within 6h after disinfection was conducted. The experimental results showed that the disinfection efficiencies had good fit with Chick-Watson first-order linear model, and US pretreatment increased the inactivation rate constant for E. coli, which increased from 0.1605 to 0.1887 in the DIK water. Therefore, US pretreatment with UV disinfection have potential to shorten the retention time and reduce the reactor volume. Moreover, the number of photoreactivated E. coli in effluent was reduced under UV-C LED disinfection with US pretreatment compared with that under UV-C LED disinfection alone. The order of maximum percentage of photo-reactivated E. coli was as follows: UV-C LED disinfection alone at 30mJ/cm2>UV-C LED disinfection at 25mJ/cm2 with US pretreatment>UV-C LED disinfection at 30mJ/cm2 with US pretreatment. The survival ratio versus photoreactivation time showed a good fit to

  2. Environmental Ionizing Radiation Survey of Quarry Sites in Ilorin ...

    African Journals Online (AJOL)

    An environmental ionizing radiation survey around quarry sites in Ilorin was carried out using three Radalert Nuclear Radiation Monitors and Global Positioning System (GPS) in order to assess and provide up to date information on radiation levels in the environment. Measured mean radiation levels ranged from 1.11±0.05 ...

  3. Linguistic Dating of Biblical Texts

    DEFF Research Database (Denmark)

    Ehrensvärd, Martin Gustaf

    2003-01-01

    For two centuries, scholars have pointed to consistent differences in the Hebrew of certain biblical texts and interpreted these differences as reflecting the date of composition of the texts. Until the 1980s, this was quite uncontroversial as the linguistic findings largely confirmed the chronol......For two centuries, scholars have pointed to consistent differences in the Hebrew of certain biblical texts and interpreted these differences as reflecting the date of composition of the texts. Until the 1980s, this was quite uncontroversial as the linguistic findings largely confirmed...... the chronology of the texts established by other means: the Hebrew of Genesis-2 Kings was judged to be early and that of Esther, Daniel, Ezra, Nehemiah, and Chronicles to be late. In the current debate where revisionists have questioned the traditional dating, linguistic arguments in the dating of texts have...... come more into focus. The study critically examines some linguistic arguments adduced to support the traditional position, and reviewing the arguments it points to weaknesses in the linguistic dating of EBH texts to pre-exilic times. When viewing the linguistic evidence in isolation it will be clear...

  4. Progress in TL Dating at Risø

    DEFF Research Database (Denmark)

    Mejdahl, V.

    1972-01-01

    This article outlines the thermoluminescent dating technique employed at Risö. The intensity of beta and gamma radiation is determined by means of the TL phosphors CaSO4:Mn and CaSO4:Dy, and the determination of accumulated exposure is based on quartz and feldspar inclusions with a size of 0.......3–0.5 mm. Results are presented of a dating programme comprising sherds, bricks, burned stones and burned clay (from kilns) from seventeen excavation sites. The age of the sites ranged from a.d. 1600 to 4000 b.c....

  5. Disinfection of herbal spa pool using combined chlorine dioxide and sodium hypochlorite treatment.

    Science.gov (United States)

    Hsu, Ching-Shan; Huang, Da-Ji

    2015-02-01

    The presence of pathogenic microorganisms in public spa pools poses a serious threat to human health. The problem is particularly acute in herbal spas, in which the herbs and microorganisms may interact and produce undesirable consequences. Accordingly, the present study investigated the effectiveness of a combined disinfectant containing chlorine dioxide and sodium hypochlorite in improving the water quality of a public herbal spa in Taiwan. Water samples were collected from the spa pool and laboratory tests were then performed to measure the variation over time of the microorganism content (total CFU and total coliforms) and residual disinfectant content given a single disinfection mode (SDM) with disinfectant concentrations of 5.2 × 10, 6.29 × 10, 7.4 × 10, and 11.4 × 10(-5) N, respectively. Utilizing the experience gained from the laboratory tests, a further series of on-site investigations was performed using three different disinfection modes, namely SDM, 3DM (once every 3 h disinfection mode), and 2DM (once every 2 h disinfection mode). The laboratory results showed that for all four disinfectant concentrations, the CFU concentration reduced for the first 6 h following SDM treatment, but then increased. Moreover, the ANOVA results showed that the sample treated with the highest disinfectant concentration (11.4 × 10(-5) N) exhibited the lowest rate of increase in the CFU concentration. In addition, the on-site test results showed that 3DM and 2DM treatments with disinfectant concentrations in excess of 9.3 × 10 and 5.5 × 10(-5) N, respectively, provided an effective reduction in the total CFU concentration. In conclusion, the experimental results presented in this study provide a useful source of reference for spa businesses seeking to improve the water quality of their spa pools.

  6. Two-step chlorination: A new approach to disinfection of a primary sewage effluent.

    Science.gov (United States)

    Li, Yu; Yang, Mengting; Zhang, Xiangru; Jiang, Jingyi; Liu, Jiaqi; Yau, Cie Fu; Graham, Nigel J D; Li, Xiaoyan

    2017-01-01

    Sewage disinfection aims at inactivating pathogenic microorganisms and preventing the transmission of waterborne diseases. Chlorination is extensively applied for disinfecting sewage effluents. The objective of achieving a disinfection goal and reducing disinfectant consumption and operational costs remains a challenge in sewage treatment. In this study, we have demonstrated that, for the same chlorine dosage, a two-step addition of chlorine (two-step chlorination) was significantly more efficient in disinfecting a primary sewage effluent than a one-step addition of chlorine (one-step chlorination), and shown how the two-step chlorination was optimized with respect to time interval and dosage ratio. Two-step chlorination of the sewage effluent attained its highest disinfection efficiency at a time interval of 19 s and a dosage ratio of 5:1. Compared to one-step chlorination, two-step chlorination enhanced the disinfection efficiency by up to 0.81- or even 1.02-log for two different chlorine doses and contact times. An empirical relationship involving disinfection efficiency, time interval and dosage ratio was obtained by best fitting. Mechanisms (including a higher overall Ct value, an intensive synergistic effect, and a shorter recovery time) were proposed for the higher disinfection efficiency of two-step chlorination in the sewage effluent disinfection. Annual chlorine consumption costs in one-step and two-step chlorination of the primary sewage effluent were estimated. Compared to one-step chlorination, two-step chlorination reduced the cost by up to 16.7%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-06-15

    Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg {center_dot} min{sup -1} showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process.

  8. Effectiveness of Disinfectants on Antimicrobial and Physical Properties of Dental Impression Materials.

    Science.gov (United States)

    Demajo, Jean Karl; Cassar, Valter; Farrugia, Cher; Millan-Sango, David; Sammut, Charles; Valdramidis, Vasilis; Camilleri, Josette

    2016-01-01

    The aim of this study was to assess the antimicrobial activity of chemical disinfectants on alginate and silicone impression materials. The effect of chemical disinfectants on the dimensional stability of the impression materials was also assessed. For the microbiologic assessment, impressions of the maxillary arch were taken from 14 participants, 7 using alginate and 7 using an addition silicone. The impressions were divided into three sections. Each section was subjected to spraying with MD 520 or Minuten or no disinfection (control), respectively. Antimicrobial action of the chemical disinfectants was assessed by measuring microbial counts in trypticase soy agar (TSA) media and expressing the results in colony-forming units/cm2. The surface area of the dental impressions was calculated by scanning a stone cast using computer-aided design/computer-assisted manufacture and analyzing the data using a custom computer program. The dimensional stability of the impression materials after immersion in disinfectants was assessed by measuring the linear displacement of horizontally restrained materials using a traveling microscope. The percent change in length over 3 hours was thus determined. Alginate exhibited a higher microbial count than silicone. MD 520 eliminated all microbes as opposed to Minuten. The bacterial growth after Minuten disinfection was almost twice as much for alginate than for addition silicone impressions. The chemical disinfectants affected the alginate dimensional stability. Minuten reduced the shrinkage sustained by alginate during the first hour of storage. Alginate harbors three times more microorganisms than silicone impression material. Chemical disinfection by glutaraldehyde-based disinfectant was effective in eliminating all microbial forms for both alginate and silicone without modifying the dimensional stability. Alcohol-based disinfectants, however, reduced the alginate shrinkage during the first 90 minutes of setting. The current studies

  9. Evaluation of Surface Microhardness Following Chemical and Microwave Disinfection of Commercially Available Acrylic Resin Denture Teeth

    Science.gov (United States)

    Gandhi, Nitasha; Daniel, Smitha; Benjamin, Sushant; Varghese, Vinaya Susan

    2017-01-01

    Introduction Denture disinfection is an indispensable procedure for preventing cross contamination and the maintenance of a healthy oral mucosa in patients rehabilitated with removable dental prosthesis. Nevertheless, they are known to cause changes in the physical and mechanical properties of denture base resins and acrylic resin denture teeth following immersion of a denture in a suitable chemical disinfectant solution or by undergoing microwave irradiation. One such mechanical property indicator for artificial tooth materials is hardness. Aim To assess the surface hardness of acrylic resin teeth of three different commercial brands (Ivoclar, Newace, Acryrock) following chemical (2% glutaraldehyde, 1% sodium hypochlorite) and microwave disinfections. Materials and Methods Ten specimens of each of the three commercial brands were made for control and each simulated disinfection type and stored in distilled water at room temperature for 24 hours. After water storage, specimens were immersed in 2% glutaraldehyde and 1% sodium hypochlorite (one and three cycles) at room temperature for 10 minutes. Irradiation with microwave (one and three cycles) was done in domestic microwave for three minutes with the specimens immersed in 150 ml of distilled water. The specimens were stored in distilled water at room temperature for seven days after each disinfection cycle. Vickers hardness measurements were made using a hardness indenter under a load of 50 g force for 10 seconds. Data was subjected to repeated measure two-way ANOVA test and Tukey’s test. Results There were statistically significant differences for the variables disinfection, tooth, and cycle (pdisinfectant interaction, pdisinfectant interaction). The mean surface hardness following one microwave disinfection cycle was lower than control, glutaraldehyde and sodium hypochlorite. Comparison among cycles revealed that microhardness was significantly decreased for three cycles of microwave disinfection. Conclusion

  10. The complexity behind the date

    CERN Multimedia

    2009-01-01

    For the waiting world, and indeed for most of us here at CERN, ‘the LHC schedule’ simply means the date that the LHC will restart - and we only take notice when that end-date changes. But in fact the schedule is a constantly evolving intricate document coordinating all the repairs, consolidation and commissioning in every part of the machine. So, what actually goes on behind the scenes in timing and planning all the work on one of the most complex scientific instruments ever built?

  11. Disinfection of sewage sludge cake by gamma-irradiation

    Science.gov (United States)

    Watanabe, Hiroshi; Takehisa, Masaaki

    Disinfection of municipal sewage sludge cake by gamma-irradiation was reviewed. Total bacterial count in the sludge cake did not vary markedly throughout all four seasons in Japan, and it was in the range of 1.6 × 10 8/g to 4.1 × 10 9/g. Coliform count in aerobically activated sludge was form 1.8 × 10 7/g to 4.8 × 10 8/g, while in anaerobically digested sludge it was less than 8.3 × 10 7/g. The dose to reduce the coliforms to undetectable levels ranged from 0.3 to 0.5 Mrad, depending on the season. In addition, it was observed that no coliforms reappeared in 0.5 Mrad irradiated sludge cake during storage at room temperature (6 - 16°C) and at 30°C. The adequate disinfection dose is therefore considered to be 0.5 Mrad. Pseudomonas cepacia was a predominant bacterium in non-irradiated sludge cake. In a range of 0.5 to 0.7 Mrad, the residual flora consisted of Bacillus species, and radioresistant Deinococcus proteolyticus, Deinococcus radiodurans and Pseudomonas radiora were isolated from sludge cake irradiated at dose levels of more than 1 Mrad. Bacterial regrowth and the growth of Escherichia coli K-12 seeded in irradiated sludge cake are discussed.

  12. Tissue disinfection for preparation of Dendrobium in vitro culture

    Directory of Open Access Journals (Sweden)

    Teixeira da Silva Jaime A.

    2016-06-01

    Full Text Available Establishing an aseptic in vitro culture for Dendrobium, or for any plant in fact, is the most important step towards developing an effective in vitro tissue culture including micropropagation protocol. Success in initial aseptic culture will contribute to the successful production of in vitro cultures that may involve the initiation or formation of callus and/or protocorm-like bodies (PLBs, the induction, regeneration or multiplication of shoots, and the preparation and proliferation of plantlets suitable for acclimatization. The initiation of an aseptic culture is closely related to the appropriate selection of an explant source and its preparation, including its (in vivo pre-treatment if necessary and subsequent disinfection procedures. Care in the choice of explant and the application of an appropriate disinfection protocol can successfully reduce, or eliminate, contamination in in vitro cultures while reducing the negative impact on plant tissues and plantlet regeneration. Many unique aseptic culture procedures for Dendrobium genus have been reported in the literature, very often specific to particular tissues or genotypes, and this review not only highlights the details of such protocols, but also provides practical advice for novice – and even seasoned – orchidologists who wish to research Dendrobium in vitro, although it is cautioned that there is currently no universal aseptic culture procedure that can be applied to all conditions, all explants or all genotypes.

  13. Disinfection kinetics of murine norovirus using chlorine and chlorine dioxide.

    Science.gov (United States)

    Lim, Mi Young; Kim, Ju-Mi; Ko, Gwangpyo

    2010-05-01

    We determined the disinfection efficiency of chlorine and chlorine dioxide (ClO(2)) using murine norovirus (MNV) and coliphage MS2 as surrogates for human norovirus. Experiments were performed in oxidant demand-free buffer (pH 7.2) at 5 degrees C and 20 degrees C. The extent of virus inactivation by a disinfectant was quantified using three different analytical methods: plaque, short template real-time TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR), and long template RT-PCR assays. Rapid inactivation of MNV by both chlorine and chlorine dioxide was observed by the plaque assay. According to the efficiency factor Hom model, Ct values of 0.314mg/Lmin and 0.247mg/Lmin were required for a 4-log reduction of MNV at 5 degrees C by chlorine and chlorine dioxide, respectively. Lower Ct values were required at 20 degrees C. Both long template and short template RT-PCR assays significantly underestimated the virus inactivation compared to the plaque assay. Our study demonstrates that adequate treatment of water with either chlorine or ClO(2) is likely to effectively control the waterborne transmission of human norovirus.

  14. Formation of organic chloramines during water disinfection: chlorination versus chloramination.

    Science.gov (United States)

    Lee, Wontae; Westerhoff, Paul

    2009-05-01

    Many of the available studies on formation of organic chloramines during chlorination or chloramination have involved model organic nitrogen compounds (e.g., amino acids), but not naturally occurring organic nitrogen in water. This study assessed organic chloramine formation during chlorination and chloramination of 16 natural organic matter (NOM) solutions and 16 surface waters which contained dissolved organic nitrogen (DON). Chlorination rapidly formed organic chloramines within 10 min, whereas chloramination formed organic chloramination much more slowly, reaching the maximum concentration between 2 and 120 h after the addition of monochloramine into the solutions containing DON. The average organic chloramine formation upon addition of free chlorine and monochloramine into the NOM solutions were 0.78 mg-Cl(2)/mg-DON at 10 min and 0.16 mg-Cl(2)/mg-DON at 24h, respectively. Organic chloramine formation upon chlorination and chloramination increased as the dissolved organic carbon/dissolved organic nitrogen (DOC/DON) ratio decreased (i.e., DON contents increased). Chlorination of molecular weight (10,000 Da) fractionated water showed that molecular weight of DON would not impact the amount of organic chloramines produced. Comparison of three different disinfection schemes at water treatment plants (free chlorine, preformed monochloramine, and chlorine/ammonia additions) indicated organic chloramine formation could lead to a possible overestimation of disinfection capacity in many chloraminated water systems that add chlorine followed by an ammonia addition to form monochloramine.

  15. Disinfection kinetics of pathogens in physicochemical sludge treated with ammonia.

    Science.gov (United States)

    Mendez, J M; Jimenez, B; Maya, C

    2004-01-01

    Ammonia is a disinfectant which can diffuse through the membrane of highly resistant structures like helminth ova. Thus, it can be considered an alternative disinfectant of wastewater sludge with high pathogenic content. In this study, the kinetic parameters of the Hom model were used to describe the inactivation with ammonia of faecal coliforms, Salmonella spp. and viable helminth ova. These were obtained in processes considering the addition of ammonia alone as well as for ammonia combined with an increase in temperature. The sludge was sampled from a municipal wastewater treatment plant using an APT (Advanced Primary Treatment) or CEP (Chemical Enhanced Primary) process. With 20% w/w of ammonia, 7 logs of faecal coliforms, 6 logs of Salmonella spp., and 83% of viable helminth ova were reduced in 2 hours contact time. To eliminate 100% of the helminth ova from samples having 88-132 ova/g TS it was needed to combine 20% of ammonia with 50 degrees C. The analysis of parameters k, n and m indicate higher resistance to inactivation of helminth ova compared to bacteria and a better performance of the ammonia process than lime stabilization to inactivate microorganisms. In addition, ammonia increased the agricultural value of the biosolids produced.

  16. Dynamics of cholera epidemics with impulsive vaccination and disinfection.

    Science.gov (United States)

    Sisodiya, Omprakash Singh; Misra, O P; Dhar, Joydip

    2018-02-07

    Waterborne diseases have a tremendous influence on human life. The contaminated drinking water causes water-borne disease like cholera. Pulse vaccination is an important and effective strategy for the elimination of infectious diseases. A waterborne disease like cholera can also be controlled by using impulse technique. In this paper, we have proposed a delayed SEIRB epidemic model with impulsive vaccination and disinfection. We have studied the pulse vaccination strategy and sanitation to control the cholera disease. The existence and stability of the disease-free and endemic periodic solution are investigated both analytically and numerically. It is shown that there exists an infection-free periodic solution, using the impulsive dynamical system defined by the stroboscopic map. It is observed that the infection-free periodic solution is globally attractive when the impulse period is less than some critical value. From the analysis of the model, we have obtained a sufficient condition for the permanence of the epidemic with pulse vaccination. The main highlight of this paper is to introduce impulse technique along with latent period into the SEIRB epidemic model to investigate the role of pulse vaccination and disinfection on the dynamics of the cholera epidemics. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Disinfection of Ebola Virus in Sterilized Municipal Wastewater.

    Directory of Open Access Journals (Sweden)

    Kyle Bibby

    2017-02-01

    Full Text Available Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids will require additional verification.

  18. Microhardness of heat cure acrylic resin after treatment with disinfectants.

    Science.gov (United States)

    Amin, Faiza; Rehman, Abdur; Abbas, Muhammad

    2015-08-01

    To evaluate the effect of disinfectants and distilled water on the micro-hardness of heat cure acrylic resins. The case-control study was conducted at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, and Nadirshaw Edulji Dinshaw University of Engineering and Technology, Karachi, from April to October 2011. Specimens were fabricated from heat cure acrylic resin material and they were divided into four equal groups. Group 1 was evaluated at baseline and was taken as the control group. Group 2 was immersed in distilled water for 20 minutes, Group 3 in1% sodium hypochlorite for 20 minutes, and Group 4 in 2% alkaline gluteraldehyde for 10 minutes. All specimens were polished, stored in distilled water for 24 hours prior to experiment. All the specimens were immersed twice daily for a total of 60 days after which they were tested for Vickers micro-hardness test. Statistical analysis was conducted with one-way analysis of variance and Tukey post hoc test (a=0.05). There were 72 specimens divided into four groups of 18(25%) each. Statistically significant differences were found among all groups (pacrylic resins. Group 4 showed the most reduction in the hardness value which was followed by Group 3. The hardness of heat cure acrylic resin was affected by disinfectants.

  19. Field-testing UV disinfection of drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Gadgil, A.; Drescher, A.; Greene, D. [Lawrence Berkeley National Lab., CA (United States); Miller, P. [Natural Resources Defense Council (United States); Motau, C. [South African Center for Essential Community Services (South Africa); Stevens, F. [Durban Metro Water (South Africa)

    1997-09-01

    A recently invented device, ``UV Waterworks,`` uses ultraviolet (UV) light to disinfect drinking water. Its novel features are: low cost, robust design, rapid disinfection, low electricity use, low maintenance, high flow rate and ability to work with unpressurized water sources. The device could service a community of 1,000 persons, at an annual total cost of less than 10 US cents per person. UV Waterworks has been successfully tested in the laboratory. Limited field trials of an early version of the device were conducted in India in 1994--95. Insights from these trials led to the present design. Extended field trials of UV Waterworks, initiated in South Africa in February 1997, will be coordinated by the South African Center for Essential Community Services (SACECS), with technical and organizational support from Lawrence Berkeley National Laboratory(LBNL) and the Natural Resources Defense Council (both US). The first of the eight planned sites of the year long trial is an AIDS hospice near Durban. Durban metro Water and LBNL lab-tested a UV Waterworks unit prior to installing it at the hospice in August, 1997. The authors describe the field test plans and preliminary results from Durban.

  20. Graphene quantum dots-band-aids used for wound disinfection.

    Science.gov (United States)

    Sun, Hanjun; Gao, Nan; Dong, Kai; Ren, Jinsong; Qu, Xiaogang

    2014-06-24

    Herein, an antibacterial system combining the "safe" carbon nanomaterials, graphene quantum dots (GQDs), with a low level of H2O2 has been put forward. It has been found that the peroxidase-like activity of GQDs originates from their ability to catalyze the decomposition of H2O2, generating ·OH. Since the ·OH has a higher antibacterial activity, the conversion of H2O2 into ·OH improves the antibacterial performance of H2O2, which makes it possible to avoid the toxicity of H2O2 at high levels in wound disinfection. All the experiments in vitro display that this intrinsic activity exerts a high enhancement of antibacterial activity of H2O2, and the designed system possessed broad spectrum of antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. More importantly, to assess the antibacterial efficacy of the designed system in actual wound disinfection, the GQD-Band-Aids are prepared and show excellent antibacterial property with the assistance of H2O2 at low dose in vivo.

  1. 21 CFR 1312.25 - Expiration date.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Expiration date. 1312.25 Section 1312.25 Food and... SUBSTANCES Exportation of Controlled Substances § 1312.25 Expiration date. An export permit shall not be valid after the date specified therein, which date shall conform to the expiration date specified in the...

  2. Peer Group Influences on Adolescent Dating Aggression

    Science.gov (United States)

    Connolly, Jennifer; Friedlander, Laura

    2009-01-01

    The peer group is a critical social context for dating and romantic relationships. Peer groups provide opportunities to meet potential dating partners and set norms for acceptable dating behaviors. This article explores how peer groups influence dating and dating aggression, as well as how they can be used in prevention efforts. It also reviews…

  3. Online Dating and Conjugal Bereavement

    Science.gov (United States)

    Young, Dannagal Goldthwaite; Caplan, Scott E.

    2010-01-01

    This study examined self-presentation in the online dating profiles of 241 widowed and 280 divorced individuals between 18 and 40 years old. A content analysis of open-ended user-generated profiles assessed the presence or absence of various themes, including the user's marital status, the backstory of their lost relationship, and whether they…

  4. Luminescence dating of delta sediments

    NARCIS (Netherlands)

    Chamberlain, Elizabeth L.; Wallinga, Jakob; Reimann, Tony; Goodbred, Steven L.; Steckler, Michael S.; Shen, Zhixiong; Sincavage, Ryan

    2017-01-01

    Deltas where luminescence dating is most essential due to organic-poor geologic records are also those where it is often most challenging due to unsuitable luminescence properties of quartz grains, associated with rapid production of young clastic sediment. One example is the

  5. Ice Core Dating Software for Interactive Dating of Ice Cores

    Science.gov (United States)

    Kurbatov, A. V.; Mayewski, P. A.; Abdul Jawad, B. S.

    2005-12-01

    Scientists involved in ice core dating are well familiar with the problem of identification and recording the depth of annual signals using stable isotopes, glaciochemistry, ECM (electrical conductivity), DEP (dielectric properties) and particle counter data. Traditionally all parameters used for ice core dating were plotted as a function of depth, printed and after years were marked on the paper, converted to depth vs. age time scale. To expedite this tedious and manual process we developed interactive computer software, Ice core Dating (ICD) program. ICD is written in Java programming language, and uses GPL and GPL site licensed graphic libraries. The same 3.5 Mb in size pre-compiled single jar file, that includes all libraries and application code, was successfully tested on WinOS, Mac OSX, Linux, and Solaris operating systems running Java VM version 1.4. We have followed the modular design philosophy in our source code so potential integration with other software modules, data bases and server side distributed computer environments can be easily implemented. We expect to continue development of new suites of tools for easy integration of ice core data with other available time proxies. ICD is thoroughly documented and comes with a technical reference and cookbook that explains the purpose of the software and its many features, and provides examples to help new users quickly become familiar with the operation and philosophy of the software. ICD is available as a free download from the Climate Change Institute web site ( under the terms of GNU GPL public license.

  6. Knowledge and behavior of dentists in a dental school regarding toothbrush disinfection.

    Science.gov (United States)

    Peker, Ilkay; Akarslan, Zuhre; Basman, Adil; Haciosmanoglu, Nur

    2015-01-01

    The aim of this study was to evaluate the knowledge and behavior of dentists regarding toothbrush disinfection. This study included 147 dentists (88 women and 59 men) who were actively employed at a dental school in Ankara, Turkey. Participants were asked to fill out a standard questionnaire, which contained questions regarding their demographics, brushing habits, toothbrush storage and disinfection habits, toothpaste use, knowledge about toothbrush disinfection, and whether they advised their patients about toothbrush storage. Descriptive statistics were calculated, and statistical analyses were performed with t-tests, chi-squared tests, and Fisher exact tests, where appropriate. Among the 147 surveyed dentists, 62.6% and 85.7% reported that they did not have any knowledge about toothbrush disinfection and did not disinfect their toothbrushes, respectively. However, approximately two thirds of surveyed dentists thought that toothbrush disinfection should be performed by everyone, including healthy individuals. Significant associations were found between knowledge about toothbrush disinfection and the professional title of dentists, how they stored their toothbrushes, and whether their toothbrushes were in contact with each other during storage (p toothbrushes.

  7. Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water.

    Science.gov (United States)

    Banach, Jennifer L; Sampers, Imca; Van Haute, Sam; van der Fels-Klerx, H J Ine

    2015-07-23

    The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant's reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer's efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer.

  8. A pilot study on using chlorine dioxide gas for disinfection of gastrointestinal endoscopes.

    Science.gov (United States)

    Yi, Ying; Hao, Li-Mei; Ma, Shu-Ren; Wu, Jin-Hui; Wang, Tao; Lin, Song; Zhang, Zong-Xing; Qi, Jian-Cheng

    2016-07-01

    This pilot study of employing chlorine dioxide (CD) gas to disinfect gastrointestinal endoscopes was conducted to meet the expectations of many endoscopy units in China for a high-efficiency and low-cost disinfectant. An experimental prototype with an active circulation mode was designed to use CD gas to disinfect gastrointestinal endoscopes. One type of testing device composed of polytetrafluoroethylene (PTFE) tubes (2 m long, inner diameter 1 mm) and bacterial carrier containers was used to simulate the channel of the endoscope. PTFE bacterial carriers inoculated with Bacillus atrophaeus with or without organic burden were used to evaluate the sporicidal activity of CD gas. Factors including exposure dosage, relative humidity (RH), and flow rate (FR) influencing the disinfection effect of CD gas were investigated. Moreover, an autoptic disinfecting test on eight real gastrointestinal endoscopes after clinical use was performed using the experimental prototype. RH, exposure dosage, organic burden, and the FR through the channel significantly (Pgas for a long and narrow lumen. The log reduction increased as FR decreased. Treatment with 4 mg/L CD gas for 30 min at 0.8 L/min FR and 75% RH, resulted in complete inactivation of spores. Furthermore, all eight endoscopes with a maximum colony-forming unit of 915 were completely disinfected. The cost was only 3 CNY (0.46 USD) for each endoscope. The methods and results reported in this study could provide a basis for further studies on using CD gas for the disinfection of endoscopes.

  9. A new method for photodynamic disinfection of prosthetic constructions and impressions in prosthetic dentistry.

    Science.gov (United States)

    Vlahova, Angelina P; Kisov, Christo K; Popova, Elka V; Haydushka, Irina A; Mantareva, Vanya N

    2012-01-01

    Photodynamic therapy is a topical treatment of pathogens that involves the use of a photoactive dye (photosensitizer), which is non-toxic when not exposed to light and activated by light of a specific wavelength in the presence of oxygen. The highly cytotoxic oxygen species generated by the induced photophysical processes inactivate the pathogenic cells. The PURPOSE of this study was to present a new method we developed for photodynamic disinfection of prostheses and impressions in prosthetic dentistry and to assess its effectiveness in comparison with some conventional methods of disinfection. The method was developed on the basis of series of experimental studies (30 experiments for each type of disinfectant, 30 controls with no disinfection for each material, and 30 direct cultures of each test microorganism--MRSA, P. aeruginosa and C. albicans) using standard test specimens made of prosthesis plastic and impression materials. The new method of photodynamic disinfection with GaPc1 as photosensitizer was 100% efficient in C-silicones, A-silicones and polyethers, but not in alginates (40%). To plastics the photodynamic method shows the same efficiency as the conventional disinfectants of hypochlorite solutions and denture cleansing tablets (100% effect). The method of photodynamic disinfection we developed is a good therapeutic choice against orally transmitted diseases in prosthetic dentistry.

  10. Life Cycle Environmental Impacts of Disinfection Technologies Used in Small Drinking Water Systems.

    Science.gov (United States)

    Jones, Christopher Holladay; Shilling, Elizabeth G; Linden, Karl G; Cook, Sherri Michelle

    2018-02-05

    Small drinking water systems serve a fifth of the U.S. population and rely heavily on disinfection. While chlorine disinfection is common, there is interest in minimizing chemical addition, especially due to carcinogenic disinfection byproducts and chlorine-resistant pathogens, by using ultraviolet technologies; however, the relative, broader environmental impacts of these technologies are not well established, especially in the context of small (water systems. The objective of this study was to identify environmental trade-offs between chlorine and ultraviolet disinfection via comparative life cycle assessment. The functional unit was the production of 1 m3 of drinking water to U.S. Treatment included cartridge filtration followed by either chlorine disinfection or ultraviolet disinfection with chlorine residual addition. Environmental performance was evaluated for various chlorine contact zone materials (plastic, concrete, steel), ultraviolet validation factors (1.2 to 4.4), and electricity sources (renewable; U.S. average, high, and low impact grids). Performance was also evaluated when filtration and chlorine residual were not required. From an LCA perspective, replacing chlorine with UV was preferred only in a limited number of cases (i.e., high pumping pressure but filtration is not required). In all others, chlorine was environmentally preferred, although some contact zone materials and energy sources had an impact on the comparison. Utilities can use these data to inform their disinfection technology selection and operation to minimize environmental and human health impacts.

  11. Effect of different disinfectants on the microhardness and roughness of acrylic resins for ocular prosthesis.

    Science.gov (United States)

    Moreno, Amália; Goiato, Marcelo C; dos Santos, Daniela M; Haddad, Marcela F; Pesqueira, Aldiéris A; Bannwart, Lisiane C

    2013-03-01

    Ocular prosthesis materials should have specific properties for their indication and durability; therefore, it is important to investigate their physical behaviour when affected by several disinfectants. This study evaluated the influence of different disinfecting solutions on the microhardness and surface roughness of acrylic resins for ocular prosthesis. Fifty samples simulating ocular prostheses were fabricated with N1 resin and colourless resin and divided (n = 10) according to the disinfectant used: neutral soap, Opti-free, Efferdent, 1% hypochlorite (HYC) and 4% chlorhexidine (CHX). Samples were stored in saline solution at 37°C and disinfected during 120 days. Both microhardness and roughness were investigated before, after 60 days and 120 days of disinfection and storage. Microhardness was measured using a microhardner and the roughness with a roughness device. N1 resin showed lower microhardness when compared with colourless resin (p acrylic resins were observed after both periods of disinfection and storage (p disinfection/storage periods affected the microhardness and roughness values of the samples. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

  12. The Effect of Disinfection of Hatching Eggs on Hatchability of Oravka Chickens

    Directory of Open Access Journals (Sweden)

    Cyril Hrnčár

    2012-10-01

    Full Text Available The aim of this the work was evaluated effect of disinfection of Oravka hatching eggs by formalin gas (20 g KMnO4+ 30 g formaldehyde of 40 % concentration to 1 m3 of a space and ozone (0.450 ppm in time 12 hours on fertility,hatchability, spontaneity of chickens hatching and embryonal mortality during incubation. The hatching was realisedin Bios Midi incubator at a standard technology process of the hatching. We recorded a positive effect of disinfectionof ozone on hatchability from fertilised eggs (91.79% compared with disinfection of formalin (91.10% A totallyembryonal mortality of chickens had not record any difference between two methods of disinfection but we recordedpositive effect of ozone on embryonic mortality of chicks to 7 day of incubation and from 15 to 21 day of incubation.We searched more spontaneous chicks hatching from hatching eggs disinfected by ozone in 510 hours of incubation.It is possible to recommend disinfection of hatching eggs by ozone, as an alternative way of disinfection of hatchingeggs usable in hatching practice, on the base of obtained experimental results. This way of disinfection hatching eggsis more ecological not only from the point of environment, but also of the healthy of employees of the hatchery.

  13. Response of Simulated Drinking Water Biofilm Mechanical and Structural Properties to Long-Term Disinfectant Exposure.

    Science.gov (United States)

    Shen, Yun; Huang, Conghui; Monroy, Guillermo L; Janjaroen, Dao; Derlon, Nicolas; Lin, Jie; Espinosa-Marzal, Rosa; Morgenroth, Eberhard; Boppart, Stephen A; Ashbolt, Nicholas J; Liu, Wen-Tso; Nguyen, Thanh H

    2016-02-16

    Mechanical and structural properties of biofilms influence the accumulation and release of pathogens in drinking water distribution systems (DWDS). Thus, understanding how long-term residual disinfectants exposure affects biofilm mechanical and structural properties is a necessary aspect for pathogen risk assessment and control. In this study, elastic modulus and structure of groundwater biofilms was monitored by atomic force microscopy (AFM) and optical coherence tomography (OCT) during three months of exposure to monochloramine or free chlorine. After the first month of disinfectant exposure, the mean stiffness of monochloramine- or free-chlorine-treated biofilms was 4 to 9 times higher than those before treatment. Meanwhile, the biofilm thickness decreased from 120 ± 8 μm to 93 ± 6-107 ± 11 μm. The increased surface stiffness and decreased biofilm thickness within the first month of disinfectant exposure was presumably due to the consumption of biomass. However, by the second to third month during disinfectant exposure, the biofilm mean stiffness showed a 2- to 4-fold decrease, and the biofilm thickness increased to 110 ± 7-129 ± 8 μm, suggesting that the biofilms adapted to disinfectant exposure. After three months of the disinfectant exposure process, the disinfected biofilms showed 2-5 times higher mean stiffness (as determined by AFM) and 6-13-fold higher ratios of protein over polysaccharide, as determined by differential staining and confocal laser scanning microscopy (CLSM), than the nondisinfected groundwater biofilms. However, the disinfected biofilms and nondisinfected biofilms showed statistically similar thicknesses (t test, p > 0.05), suggesting that long-term disinfection may not significantly remove net biomass. This study showed how biofilm mechanical and structural properties vary in response to a complex DWDS environment, which will contribute to further research on the risk assessment and control of biofilm-associated-pathogens in DWDS.

  14. Evaluation of different sterilization and disinfection methods on commercially made preformed crowns

    Directory of Open Access Journals (Sweden)

    Yilmaz Y

    2008-01-01

    Full Text Available The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM. Preformed crowns (NuSmile Primary Anterior Crown (NSC, Kinder Krowns (KK, Pedo Pearls (PP and polycarbonate crowns (PC were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group; steam autoclaving at 134 °C (30 psi for 4 min (G2; steam autoclaving at 134 °C (30 psi for 12 min (G3; steam autoclaving at 121 °C (15 psi for 30 min (G4; and ultrasonication in a bath containing 4% Lysetol ® AF for 5 min at room temperature (chemical disinfection (G5. Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P < 0.05 crazing and contour alterations of the vestibular surface of the crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients.

  15. Efficacy of detergent and water versus bleach for disinfection of direct contact ophthalmic lenses.

    Science.gov (United States)

    Abbey, Ashkan M; Gregori, Ninel Z; Surapaneni, Krishna; Miller, Darlene

    2014-06-01

    Although manufacturers recommend cleaning ophthalmic lenses with detergent and water and then with a specific disinfectant, disinfectants are rarely used in ophthalmic practices. The aim of this pilot study was to evaluate the efficacy of detergent and water versus that of bleach, a recommended disinfectant, to eliminate common ocular bacteria and viruses from ophthalmic lenses. Three bacterial strains (Staphylococcus epidermidis, Corynebacterium straitum, and methicillin-resistant Staphylococcus aureus and 2 viral strains (adenovirus and herpes simplex virus [HSV] type-1) were individually inoculated onto 20 gonioscopy and laser lenses. The lenses were washed with detergent and water and then disinfected with 10% bleach. All the lenses were cultured after inoculation, after washing with detergent and water, and after disinfecting with the bleach. Bacterial cultures in thioglycollate broth were observed for 3 weeks, and viral cultures were observed for 2 weeks. The presence of viruses was also detected by multiplex polymerase chain reaction (PCR). All 20 lenses inoculated with S. epidermidis, C. straitum, adenovirus, and HSV-1 showed growth after inoculation but no growth after washing with detergent/water and after disinfecting with the bleach. All lenses showed positive HSV and adenovirus PCR results after inoculation and negative PCR results after washing with detergent/water and after disinfecting with bleach. All methicillin-resistant S. aureus-contaminated lenses showed growth after inoculation and no growth after washing with detergent and water. However, 1 lens showed positive growth after disinfecting with bleach. Cleaning with detergent and water seemed to effectively eliminate bacteria and viruses from the surface of contaminated ophthalmic lenses. Further studies are warranted to design practical disinfection protocols that minimize lens damage.

  16. Metals releases and disinfection byproduct formation in domestic wells following shock chlorination

    Directory of Open Access Journals (Sweden)

    M. Walker

    2011-01-01

    Full Text Available Shock chlorination is used for rapid disinfection to control pathogens and nuisance bacteria in domestic wells. A typical shock chlorination procedure involves adding sodium hypochlorite in liquid bleach solutions to achieve concentrations of free chlorine of up to 200 mg L−1 in the standing water of a well. The change in pH and oxidation potential may bring trace metals from aquifer materials into solution and chlorine may react with dissolved organic carbon to form disinfection byproducts. We carried out experiments with four wells to observe and determine the persistence of increased concentrations of metals and disinfection byproducts. Water samples from shock chlorinated wells were analyzed for Pb, Cu, As, radionuclides and disinfection byproducts (haloacetic acids and trihalomethanes, immediately prior to treatment, after sufficient treatment time with chlorine had elapsed, and at intervals determined by the number of casing volumes purged, for up to four times the well casing volume.

    Elevated concentrations of lead and copper dissipated in proportion to free chlorine (measured semi-quantitatively during the purging process. Trihalomethanes and haloacetic acids were formed in wells during disinfection. In one of two wells tested, disinfection byproducts dissipated in proportion to free chlorine during purging. However, one well retained disinfection byproducts and free chlorine after 4 WV had been purged. Although metals returned to background concentrations in this well, disinfection byproducts remained elevated, though below the MCL. This may have been due to well construction characteristics and interactions with aquifer materials. Simple chlorine test strips may be a useful method for indicating when purging is adequate to remove metals and disinfection by-products mobilized and formed by shock chlorination.

  17. Effect of chemical and microwave disinfection on the surface microhardness of acrylic resin denture teeth.

    Science.gov (United States)

    Vasconcelos, Ligia Regina; Consani, Rafael Leonardo Xediek; Mesquita, Marcelo Ferraz; Sinhoreti, Mário Alexandre Coelho

    2013-06-01

    The purpose of this study was to evaluate the effect of simulated disinfections (2% glutaraldehyde, 1% sodium hypochlorite, and microwave energy) on the surface hardness of Trilux, Biocler, Biotone, New Ace, and Magister commercial artificial teeth. Specimens (n = 10) were made with the teeth included individually in circular blocks of acrylic resin, leaving the labial surface exposed. Cycles of simulated chemical disinfection were accomplished with the specimens immersed in the solutions at room temperature for 10 minutes, followed by tap water washing for 30 seconds and storage in distilled water at room temperature for 7 days until the next disinfection. Simulated disinfection by microwave energy was carried out in a domestic oven with 1300 W at a potency of 50% for 3 minutes with the specimens individually immersed in 150 ml of distilled water. Control (no disinfection) and the experimental groups (first and third disinfection cycles) were submitted to Knoop hardness measurements with indentations at the center of the labial tooth surface. Data were submitted to repeated measure two-way ANOVA and Tukey's test (α = 0.05). Biocler, Magister, and Trilux showed lower surface microhardness when submitted to microwave. Lower microhardness for Biotone was promoted by hypochlorite, while no significant difference was shown for New Ace. The third disinfection cycle significantly decreased the tooth surface hardness only for microwave. Different disinfection methods promoted different effects on the microhardness of different types of artificial teeth. Surface microhardness of the teeth was less affected by the simulated chemical disinfections when compared to microwaved specimens. © 2013 by the American College of Prosthodontists.

  18. Demonstration of disinfection procedure for the development of accurate blood glucose meters in accordance with ISO 15197:2013.

    Directory of Open Access Journals (Sweden)

    Shu-Ping Lin

    Full Text Available Despite measures to reduce disease transmission, a risk can occur when blood glucose meters (BGMs are used on multiple individuals or by caregivers assisting a patient. The laboratory and in-clinic performance of a BGM system before and after disinfection should be demonstrated to guarantee accurate readings and reliable control of blood glucose (BG for patients. In this study, an effective disinfection procedure, conducting wiping 10 times to assure a one minute contact time of the disinfectant on contaminated surface, was first demonstrated using test samples of the meter housing materials, including acrylonitrile butadiene styrene (ABS, polymethyl methacrylate (PMMA, and polycarbonate (PC, in accordance with ISO 15197:2013. After bench studies comprising 10,000 disinfection cycles, the elemental compositions of the disinfected ABS, PMMA, and PC samples were almost the same as in the original samples, as indicated by electron spectroscopy for chemical analysis. Subsequently, the validated disinfection procedure was then directly applied to disinfect 5 commercial BGM systems composed of ABS, PMMA, or PC to observe the effect of the validated disinfection procedure on meter accuracy. The results of HBsAg values after treatment with HBV sera and disinfectant wipes for each material were less than the LoD of each material of 0.020 IU/mL. Before and after the multiple disinfection cycles, 900 of 900 samples (100% were within the system accuracy requirements of ISO 15197:2013. All of the systems showed high performance before and after the series of disinfection cycles and met the ISO 15197:2013 requirements. In addition, our results demonstrated multiple cleaning and disinfection cycles that represented normal use over the lifetime of a meter of 3-5 years. Our validated cleaning and disinfection procedure can be directly applied to other registered disinfectants for cleaning commercial BGM products in the future.

  19. Radiation Therapy: Professions in Radiation Therapy

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Professions in Radiation Therapy Radiation Oncologist Therapeutic Medical Physicist Radiation Therapist Dosimetrist Radiation Oncology Nurse Social Worker Dietitian Radiation Oncologist Radiation oncologists are physicians who oversee the ...

  20. Radiation-Induced Vaccination to Breast Cancer

    Science.gov (United States)

    2015-10-01

    Award Number: W81XWH-11-1-0531 TITLE: Radiation-Induced Vaccination to Breast Cancer PRINCIPAL INVESTIGATOR: William H. McBride CONTRACTING...FORM TO THE ABOVE ADDRESS. 1. REPORT DATE 2. REPORT TYPE Annual 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Radiation-Induced Vaccination to...determine abscopal responses that are hypothesized to be due to RT- induced vaccination . RT was started 10 days after the first and 3rd dose of

  1. Biofilms and Oxidizing Biocides; Evaluation of Disinfection and Removal Effects by Using Established Microbial Systems.

    Science.gov (United States)

    Tachikawa, Mariko

    2017-01-01

    The formation of bacterial biofilms and their disinfection and removal have been important subjects in the maintenance of water quality in areas such as public spas, swimming pools, food processing lines, industrial water systems, and in the hygienic control of medical devices, hospital procedures, etc. Presented here is an outline of biofilm formation, as well as studies on the disinfection and removal of biofilms by oxidizing biocides using established biofilms. These studies using established biofilms may increase the understanding of the variable response of biofilms to planktonic bacteria, and the unique aspects of oxidizing biocides in the disinfection and removal of biofilms.

  2. Influence of sublethal concentrations of common disinfectants on expression of virulence genes in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Larsen, M. H.; Gram, Lone

    2010-01-01

    Listeria monocytogenes is a food-borne human pathogen that causes listeriosis, a relatively rare infection with a high fatality rate. The regulation of virulence gene expression is influenced by several environmental factors, and the aim of the present study was to determine how disinfectants used...... perspective, the study underlines that disinfectants should be used at the lethal concentrations recommended by the manufacturers. Further studies are needed to elucidate whether the changes in virulence gene expression induced by the disinfectants have impact on virulence or other biological properties...

  3. Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: a review

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Beerendonk, E.F.; Medema, Gerriet Jan

    2006-01-01

    UV disinfection technology is of growing interest in the water industry since it was demonstrated that UV radiation is very effective against (oo)cysts of Cryptosporidium and Giardia, two pathogenic micro-organisms of major importance for the safety of drinking water. Quantitative Microbial Risk

  4. APPLICATION OF ULTRAVIOLET RADIATION TO CONTROL MICROBIOLOGICALLY INFLUENCED CORROSION: A CASE STUDY ON SOIL SAMPLE FROM MANGROVE

    Directory of Open Access Journals (Sweden)

    MUHAMMAD KHAIROOL FAHMY BIN MOHD ALI

    2016-12-01

    Full Text Available Microbiologically influenced corrosion (MIC is significant to the presence of microorganisms such as sulfate reducing bacteria (SRB in the deterioration of metallic and non-metallic materials. Bacterial chemical biocides are commonly used to disinfect microorganism effectively. Yet, the practice has some negative impact on the environment since the chemical content may cause pollution. A laboratory experimental investigation was conducted to explore the performance of Ultraviolet (UV radiation in exterminating SRB as an option to replace biocides usage. The morphologies of the isolated Sg. Ular SRB used in this study were related to Desulfovibrio species. An experimental work was conducted in determining the optimum pH and temperature for the SRB to grow before disinfection purposes. The experimental result showed optimum growth for respective SRB were at pH of 8.5 with temperature recorded at 37˚C. UV radiation with wavelength of 254 nm was utilised to disinfect the microorganism. SRB samples were exposed to UV radiation for one hour and left incubated for 21 days. It was found that the percentage of metal loss in a sample exposed to UV radiation was lower compared with untreated sample. Results from the study revealed that UV has a potential as a viable option for SRB disinfection purposes and may be further developed to reduce the consumption of chemical biocides in pipeline maintenance scheme.

  5. Study of the effects of {gamma}-radiation followed by chlorination with hypochlorite on coliforms in sterile buffered samples

    Energy Technology Data Exchange (ETDEWEB)

    Tata, A.; Festinesi, A.; Rosa, R.; Adamo, A.; Rossi, G. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Innovazione

    1998-04-01

    Radiation and chlorination combined treatment of water samples is investigated in order to evaluate the disinfecting efficacy, observing the growth of reference organisms. [Italiano] Nel presente lavoro sono illustrati i risultati delle analisi condotte su campioni di acqua sottoposti a trattamento combinato con radiazioni e clorazione, al fine di valutare l`efficacia mediante l`osservazione della crescita di organismi di riferimento.

  6. Studies on application of radiation and radioisotopes -Studies on radiation processing-

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Hah; Yoon, Byung Mok; Kim, Kee Yub; Noh, Yung Chang; Lee, Yung Keun; Lee, Myun Joo; Park, Soon Chul; Nah, Bong Joo; Kim, Jae Hoh; Byun, Hyung Jik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    Using {gamma}-ray and electron beam, acrylic acid was grafted on polyethylene film in the presence of additives such as acid and metallic salts. The effect of metal salts and acid on the graft yield was evaluated. The graft mechanism and the physical property of grafted films were also examined. Radiation sensitivities of pathogenic microbes in waste sludges were determined to get theoretical radiation dose for disinfection. Experimental radiation dose for disinfection was investigated using real activated and digestive sludge. Feasibility of the method was studied from the experimental results. Virgin, waste and regenerated activated carbon were irradiated with electron beam with and without steam. Micropore distribution, BET surface area and sorption capacity were measured before and after irradiation. The residence time distributions of flue gas in the irradiation chamber of an electron beam flue gas treatment plant to study the effect of baffles were measured. The flow rates of gaseous material in the propylene production plant were measured to identify the origin of it`s malfunction. The equipment for column scanning were designed for production. 45 figs, 10 tabs, 30 refs. (Author).

  7. Adolescent Bullying, Dating, and Mating

    Directory of Open Access Journals (Sweden)

    Anthony A. Volk

    2015-11-01

    Full Text Available Traditionally believed to be the result of maladaptive development, bullying perpetration is increasingly being viewed as a potentially adaptive behavior. We were interested in determining whether adolescents who bully others enjoy a key evolutionary benefit: increased dating and mating (sexual opportunities. This hypothesis was tested in two independent samples consisting of 334 adolescents and 144 university students. The data partly supported our prediction that bullying, but not victimization, would predict dating behavior. The data for sexual behavior more clearly supported our hypothesis that bullying behavior predicts an increase in sexual opportunities even when accounting for age, sex, and self-reports of attractiveness, likeability, and peer victimization. These results are generally congruent with the hypothesis that bullying perpetration is, at least in part, an evolutionary adaptive behavior.

  8. Linguistic dating of biblical texts

    DEFF Research Database (Denmark)

    Young, Ian; Rezetko, Robert; Ehrensvärd, Martin Gustaf

    Since the beginning of critical scholarship biblical texts have been dated using linguistic evidence. In recent years this has become a controversial topic, especially with the publication of Ian Young (ed.), Biblical Hebrew: Studies in Chronology and Typology (2003). However, until now there has...... been no introduction and comprehensive study of the field. Volume 1 introduces the field of linguistic dating of biblical texts, particularly to intermediate and advanced students of biblical Hebrew who have a reasonable background in the language, having completed at least an introductory course...... in this volume are: What is it that makes Archaic Biblical Hebrew archaic , Early Biblical Hebrew early , and Late Biblical Hebrew late ? Does linguistic typology, i.e. different linguistic characteristics, convert easily and neatly into linguistic chronology, i.e. different historical origins? A large amount...

  9. Current topics in ESR dating

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Anne R., E-mail: Anne.R.Skinner@williams.edu [Williams College, Williamstown, MA (United States)

    2011-09-15

    After over 25 years, the use of electron spin resonance (ESR) is well-established in dating sites of geological, paleontological and archaeological interest. Like any scientific technique, there have been changes in understanding and in methodology. Improvements have not, however, changed the observation that external dose calculations are still a significant source of uncertainty in ages. Examples from Europe, Africa and the Americans illustrate this point. For Pradayrol Cave (France), the occupation age, 330 ka, is unchallenged, making this the oldest known Neanderthal site in France. For Roc de Marsal, also in France, on the other hand, discrepancies between TL and sedimentary dose rates imply substantial differences in interpretation. In the Western Egyptian Desert, where artifacts and datable material are not well-correlated, the dating results show consistency with expectations based on global climate change, even in deflated sites. Climate change is also the question in geological studies in the Bahamas where, despite concerns about cosmic dose history, ESR dates confirm other evidence for sea level changes. We show that an uncertain age is not the same as an impossible one.

  10. Pathogens protection against the action of disinfectants in multispecies biofilms

    Directory of Open Access Journals (Sweden)

    Pilar eSanchez-Vizuete

    2015-07-01

    Full Text Available Biofilms constitute the prevalent way of life for microorganisms in both natural and man-made environments. Biofilm-dwelling cells display greater tolerance to antimicrobial agents than those that are free-living, and the mechanisms by which this occurs have been investigated extensively using single-strain axenic models. However, there is growing evidence that interspecies interactions may profoundly alter the response of the community to such toxic exposure. In this paper, we propose an overview of the studies dealing with multispecies biofilms resistance to biocides, with particular reference to the protection of pathogenic species by resident surface flora when subjected to disinfectants treatments. The mechanisms involved in such protection include interspecies signaling, interference between biocides molecules and public goods in the matrix or the physiology and genetic plasticity associated with a structural spatial arrangement. After describing these different mechanisms, we will discuss the experimental methods available for their analysis in the context of complex multispecies biofilms.

  11. Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, Dae Cheol; Park, Peom [Ajou Univ., Suwon (Korea, Republic of)

    2001-12-15

    A bacteria infection on film cassette contact surface was examined at the diagnostic radiology department. Studies have demonstrated a bactericidal effect of ultraviolet irradiation, and to assess the contamination level on film cassette contact surface as a predictor of patient prevent from nosocomial infection. The study showed that the laboratory result was identified non-pathologic and pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection practices suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In conclusion, ultraviolet irradiate on film cassette over the surface more than 2 minutes. Ultraviolet dose of 1565 {mu}W {center_dot} s/cm{sup 2}Win in 30 second relative to ultraviolet dose in time.

  12. Ozone reactions with indoor materials during building disinfection

    DEFF Research Database (Denmark)

    Poppendieck, D.; Hubbard, H.; Ward, M.

    2007-01-01

    There is scant information related to heterogeneous indoor chemistry at ozone concentrations necessary for the effective disinfection of buildings, i.e., hundreds to thousands of ppm. In the present study, 24 materials were exposed for 16 h to ozone concentrations of 1000-1200ppm in the inlet...... streams of test chambers. Initial ozone deposition velocities were similar to those reported in the published literature for much lower ozone concentrations, but decayed rapidly as reaction sites on material surfaces were consumed. For every material, deposition velocities converged to a relatively...... constant, and typically low, value after approximately I I h. The four materials with the highest sustained deposition velocities were ceiling tile, office partition, medium density fiberboard and gypsum wallboard backing. Analysis of ozone reaction probabilities indicated that throughout each experiment...

  13. Effects of household handling on disinfection by-products

    Directory of Open Access Journals (Sweden)

    Hesham Z. Ibrahim

    2015-10-01

    Full Text Available Chlorinated water samples were used to determine the effect of handling modes on disinfection byproducts (DBPs. The DBPs studied were trihalomethanes (THMs, haloacetonitriles (HANs, chloral hydrate (CH, chloropicrin (CP and 1,1,1-trichloropropanone (TCP. Tap water samples were collected from the distribution system in Damanhour City (Egypt. The investigated strategies included storing water in covered and uncovered bottles in a refrigerator up to 9 hours, with and without previous short boiling. Water quality parameters were not affected by storage or boiling except for electrical conductivity (EC, which decreased after boiling. 90% of THMs were removed by boiling and storage for 9hrs.HANs, including dichloroacetonitrile (DCAN, dibromoacetonitrile (DBAN and trichloroacetonitrile (TCAN, were not affected by storage, but they were not detected after boiling for 30 seconds. CH and TCP, like the HANs, were affected by boiling rather than storage.

  14. What must be done to prevent another humidifier disinfectant disaster?

    Directory of Open Access Journals (Sweden)

    Jong-Hyeon Lee

    2016-11-01

    Full Text Available The humidifier disinfectant disaster (HDD was not a simple poisoning accident by biocides, but a singular disaster in history created by chemicals in household products. This disaster was a result of the failure of a system for the management of chemical and product safety. Since the management authority for chemical usage safety is different from those for chemical safety in products, many blind areas for chemical safety management in products still remain. The ‘Act on the Registration and Evaluation, etc. of Chemical Substances (ARECS’ or the new ‘Biocidal Product Act’ must not only address the blind areas in the management system for chemical and product safety, but also prevent a second HDD. To prevent another HDD, an integrated registration, evaluation, and management system for chemicals and consumer products must be incorporated into the ‘ARECS’ as an essential part for chemical safety in consumer products.

  15. Lung Transplantation for Chronic Humidifier Disinfectant-Associated Lung Injury

    Directory of Open Access Journals (Sweden)

    Won-Young Kim

    2016-05-01

    Full Text Available In the spring of 2011, a cluster of lung injuries caused by humidifier disinfectant (HD usage were reported in Korea. Many patients required mechanical ventilation, extracorporeal membrane oxygenation, and even lung transplantation (LTPL. However, the long-term course of HD-associated lung injury remains unclear because the majority of survivors recovered normal lung function. Here we report a 33-year-old woman who underwent LTPL approximately four years after severe HD-associated lung injury. The patient was initially admitted to the intensive care unit and was supported by a high-flow nasal cannula. Although she had been discharged, she was recurrently admitted to our hospital due to progressive lung fibrosis and a persistent decline in lung function. Finally, sequential double LTPL was successfully performed, and the patient’s clinical and radiological findings showed significant improvement. Therefore, we conclude that LTPL can be a therapeutic option for patients with chronic inhalation injury.

  16. Use of peracetic acid in disinfection of wastewater: a review

    Directory of Open Access Journals (Sweden)

    Grasiele Soares Cavallini

    2012-04-01

    Full Text Available The use of peracetic acid (PAA to disinfect the wastewater has been researched for diverse authors, mainly in European countries, where the microbiological standards to release the effluents in water bodies are more severe and the moderation to use chlorine, due to the raising of trihalometanos is recommended. In this perspective, this work presents a compilation of researches applied directly to environmental sanitation, as well as the researches related to chemical characteristics of PAA and its reaction mechanisms. The combination of this information gives a theoretical and practical view of the use of this oxidant, which contributes to continue the researches in this area, aiming to benefit the environment, economy and public health system.

  17. RADIATION ACOUSTICS

    OpenAIRE

    Lyamshev, L.

    1990-01-01

    Radiation acoustics is a new branch of acoustics. Its' fundamentals are lying in the research of acoustical effects due to the interaction of a radiation with matter. The sound excitation in liquids and solids by modulated or pulsed particle beams (electron, proton, ion beams, γ-radiation and single high-energy elementary particles) and some practical applications are discussed.

  18. Evaluation of antiviral effects of various disinfectants on dental handpieces

    Directory of Open Access Journals (Sweden)

    Hasani Tabatabai M

    2007-01-01

    Full Text Available Background and Aim: Handpieces are in current use in dental practice. Cross contamination from these instruments is very high because of their direct contact with blood and saliva. The purpose of this study was the evaluation of antiviral effects of different disinfectants on dental handpieces. Materials and Methods: In this experimental study, the effects of 5 groups of different materials and methods of sterilization and disinfection on virus elimination from dental handpieces were evaluated. Groups were as follows: 1- autoclave 2- Solarsept 3- Unisepta 4- Sodium hypochlorite (2% solution of household bleach 5- Sanosil. 14 handpieces in each group were washed, dried and autoclaved, then contaminated with polio and Herpes Simplex virus type I. Samples were washed with sterile distilled water. Antiviral agents were applied according to the manufacturer or previous investigations. After washing with water, the instruments were washed with MEM (Minimum Essential Medium and two samples of cell culture from each handpiece were prepared. In each group one handpiece was treated as control. The results were recorded after one week. Results: The percent of negative cell cultures in each group were as follow: A- For Poliovirus: 1- Autoclave: 100%. 2- Solarsept: 28.6%. 3- Unisepta: 0%. 4- Sodium hypochlorite: 28.6%. 5- Sanosil 92.9%. B- For Herpesvirus: 1- Autoclave: 100%. 2- Solarsept: 100%. 3- Unisepta: 100%. 4- Sodium hypochlorite: 57.1%. 5- Sanosil: 100%. Conclusion: According to our findings autoclave is the best method for virus elimination from dental handpieces. Sanosil with 92.9% efficiency was the best solution. Solarsept, hypochlorite with special method and Unisepta had the lowest effectiveness.

  19. Electrochemical disinfection of dental implants--a proof of concept.

    Directory of Open Access Journals (Sweden)

    Dirk Mohn

    Full Text Available BACKGROUND: Peri-implantitis has gained significant clinical attention in recent years. This disease is an inflammatory reaction to microorganisms around dental implants. Due to the limited accessibility, non-invasive antimicrobial strategies are of high interest. An unexpected approach to implant disinfection may evolve from electrolysis. Given the electrical conductivity of titanium implants, alkalinity or active oxidants can be generated in body fluids. We investigated the use of dental titanium implants as electrodes for the local generation of disinfectants. Our hypothesis was that electrolysis can reduce viable counts of adhering bacteria, and that this reduction should be greater if active oxidative species are generated. METHODOLOGY/PRINCIPAL FINDINGS: As model systems, dental implants, covered with a mono-species biofilm of Escherichia coli C43, were placed in photographic gelatin prepared with physiological saline. Implants were treated by a continuous current of 0-10 mA for 15 minutes. The reduction of viable counts was investigated on cathodes and anodes. In separate experiments, the local change in pH was visualized using color indicators embedded in the gelatin. Oxidative species were qualitatively detected by potassium iodide-starch paper. The in situ generated alkaline environment around cathodic implants caused a reduction of up to 2 orders of magnitude in viable E. coli counts. On anodic implants, in contrast to cathodic counterparts, oxidative species were detected. Here, a current of merely 7.5 mA caused complete kill of the bacteria. CONCLUSIONS/SIGNIFICANCE: This laboratory study shows that electrochemical treatment may provide access to a new way to decontaminate dental implants in situ.

  20. Quantification of air plasma chemistry for surface disinfection

    Science.gov (United States)

    Pavlovich, Matthew J.; Clark, Douglas S.; Graves, David B.

    2014-12-01

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications.