The Experts below are selected from a list of 33915 Experts worldwide ranked by ideXlab platform
David J Weber - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a rapid readout biological Indicator for flash sterilization with three biological Indicators and three Chemical Indicators
Infection Control and Hospital Epidemiology, 1993Co-Authors: William A Rutala, Maria F Gergen, David J WeberAbstract:Objective Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological Indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological Indicator that provides results within 60 minutes with three conventional, 24-hour biological Indicators for monitoring flash sterilization and three Chemical Indicators. Design Conventional biological Indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout Indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical Indicators tested included Comply, Incheque, and Thermalog S. Survival at 132 degrees C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56 degrees C for the three conventional biological Indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological Indicator, and color change for the Chemical Indicators. Each exposure time was replicated four times with 10 of each biological and Chemical Indicator per run. Results The conventional biological Indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological Indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The Chemical Indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively. Conclusion The sensitivity of the Attest Rapid Readout parallels the conventional biological Indicators. These data suggest that a 60-minute rapid readout biological Indicator is equivalent to the 24-hour biological Indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical Indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.
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evaluation of a rapid readout biological Indicator for flash sterilization with three biological Indicators and three Chemical Indicators
Infection Control and Hospital Epidemiology, 1993Co-Authors: William A Rutala, Maria F Gergen, David J WeberAbstract:Objective: Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological Indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological Indicator that provides results within 60 minutes with three conventional, 24-hour biological Indicators for monitoring flash sterilization and three Chemical Indicators. Design: Conventional biological Indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout Indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical Indicators tested included Comply, Incheque, and Thermalog S. Survival at 132°C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56°C for the three conventional biological Indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological Indicator, and color change for the Chemical Indicators. Each exposure time was replicated four times with 10 of each biological and Chemical Indicator per run. Results: The conventional biological Indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological Indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The Chemical Indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively. Conclusion: The sensitivity of the Attest Rapid Readout parallels the conventional biological Indicators. These data suggest that a 60-minute rapid readout biological Indicator is equivalent to the 24-hour biological Indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical Indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.
William A Rutala - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a rapid readout biological Indicator for flash sterilization with three biological Indicators and three Chemical Indicators
Infection Control and Hospital Epidemiology, 1993Co-Authors: William A Rutala, Maria F Gergen, David J WeberAbstract:Objective Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological Indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological Indicator that provides results within 60 minutes with three conventional, 24-hour biological Indicators for monitoring flash sterilization and three Chemical Indicators. Design Conventional biological Indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout Indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical Indicators tested included Comply, Incheque, and Thermalog S. Survival at 132 degrees C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56 degrees C for the three conventional biological Indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological Indicator, and color change for the Chemical Indicators. Each exposure time was replicated four times with 10 of each biological and Chemical Indicator per run. Results The conventional biological Indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological Indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The Chemical Indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively. Conclusion The sensitivity of the Attest Rapid Readout parallels the conventional biological Indicators. These data suggest that a 60-minute rapid readout biological Indicator is equivalent to the 24-hour biological Indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical Indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.
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evaluation of a rapid readout biological Indicator for flash sterilization with three biological Indicators and three Chemical Indicators
Infection Control and Hospital Epidemiology, 1993Co-Authors: William A Rutala, Maria F Gergen, David J WeberAbstract:Objective: Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological Indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological Indicator that provides results within 60 minutes with three conventional, 24-hour biological Indicators for monitoring flash sterilization and three Chemical Indicators. Design: Conventional biological Indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout Indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical Indicators tested included Comply, Incheque, and Thermalog S. Survival at 132°C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56°C for the three conventional biological Indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological Indicator, and color change for the Chemical Indicators. Each exposure time was replicated four times with 10 of each biological and Chemical Indicator per run. Results: The conventional biological Indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological Indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The Chemical Indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively. Conclusion: The sensitivity of the Attest Rapid Readout parallels the conventional biological Indicators. These data suggest that a 60-minute rapid readout biological Indicator is equivalent to the 24-hour biological Indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical Indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.
Malcolm J Andrews - One of the best experts on this subject based on the ideXlab platform.
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measurements of molecular mixing in a high schmidt number rayleigh taylor mixing layer
Journal of Fluid Mechanics, 2009Co-Authors: Nicholas J Mueschke, Oleg Schilling, D L Youngs, Malcolm J AndrewsAbstract:Molecular mixing measurements are reported for a high-Schmidt-number ( Sc ~ 10 3 ), small-Atwood-number ( A ≈ 7.5 × 10 −4 ) buoyancy-driven turbulent Rayleigh–Taylor (RT) mixing layer in a water channel facility. Salt was added to the top water stream to create the desired density difference. The degree of molecular mixing was measured as a function of time by monitoring a diffusion-limited Chemical reaction between the two fluid streams. The pH of each stream was modified by the addition of acid or alkali such that a local neutralization reaction occurred as the two fluids molecularly mixed. The progress of this neutralization reaction was tracked by the addition of phenolphthalein – a pH-sensitive Chemical Indicator – to the acidic stream. Accurately calibrated backlit optical techniques were used to measure the average concentration of the coloured Chemical Indicator. Comparisons of Chemical product formation for pre-transitional buoyancy- and shear-driven mixing layers are given. It is also shown that experiments performed at different equivalence ratios (acid/alkali concentrations) can be combined to obtain a mathematical relationship between the coloured product formed and the density variance. This relationship was used to obtain high-fidelity quantitative measures of the degree of molecular mixing which are independent of probe resolution constraints. The dependence of molecular mixing on the Schmidt and Reynolds numbers is examined by comparing the current Sc ~ 10 3 measurements with previous Sc = 0.7 gas-phase and Pr = 7 (where Pr is the Prandtl number) liquid-phase measurements. This comparison indicates that the Schmidt number has a large effect on the quantity of mixed fluid at small Reynolds numbers Re h 3 . At larger Reynolds numbers, corresponding to later times in this experiment, all mixing parameters indicated a greater degree of molecular mixing and a decreased Schmidt number dependence. Implications for the development and quantitative assessment of turbulent transport and mixing models appropriate for RT instability-induced mixing are discussed.
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measurements of molecular mixing in a high schmidt number rayleigh taylor mixing layer
Journal of Fluid Mechanics vol. 632 N A August 1 2009 pp. 17-48, 2007Co-Authors: Nicholas J Mueschke, Oleg Schilling, D L Youngs, Malcolm J AndrewsAbstract:Molecular mixing measurements are performed for a high Schmidt number (Sc {approx} 10{sup 3}), small Atwood number (A {approx} 7.5 x 10{sup -4}) buoyancy-driven turbulent Rayleigh-Taylor mixing layer in a water channel facility. Salt was added to the top stream to create the desired density difference. The degree of molecular mixing was measured as a function of time by monitoring a diffusion-limited Chemical reaction between the two fluid streams. The pH of each stream was modified by the addition of acid or alkali such that a local neutralization reaction occurred as the two fluids molecularly mixed. The progress of this neutralization reaction was tracked by the addition of phenolphthalein - a pH-sensitive Chemical Indicator - to the acidic stream. Accurately calibrated backlit optical techniques were used to measure the average concentration of the colored Chemical Indicator. Comparisons of Chemical product formation for pre-transitional buoyancy- and shear-driven mixing layers are given. It is also shown that experiments performed at different equivalence ratios (acid/alkali concentration) can be combined to obtain a mathematical relationship between the colored product formed and the density variance. This relationship was used to obtain high-fidelity, quantitative measures of the degree of molecular mixing which are independent of probemore » resolution constraints. The dependence of such mixing parameters on the Schmidt and Reynolds numbers is examined by comparing the current Sc {approx} 10{sup 3} measurements with Sc = 0.7 gas-phase and Pr = 7 liquid-phase measurements. This comparison indicates that the Schmidt number has a large effect on the bulk quantity of mixed fluid at small Reynolds numbers Re{sub h} < 10{sup 3}. At late times, all mixing parameters indicated a greater degree of molecular mixing and a decreased Schmidt number dependence. Implications for the development and quantitative assessment of turbulent transport and mixing models appropriate for Rayleigh?Taylor instability-induced mixing are discussed.« less
Maria F Gergen - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a rapid readout biological Indicator for flash sterilization with three biological Indicators and three Chemical Indicators
Infection Control and Hospital Epidemiology, 1993Co-Authors: William A Rutala, Maria F Gergen, David J WeberAbstract:Objective Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological Indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological Indicator that provides results within 60 minutes with three conventional, 24-hour biological Indicators for monitoring flash sterilization and three Chemical Indicators. Design Conventional biological Indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout Indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical Indicators tested included Comply, Incheque, and Thermalog S. Survival at 132 degrees C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56 degrees C for the three conventional biological Indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological Indicator, and color change for the Chemical Indicators. Each exposure time was replicated four times with 10 of each biological and Chemical Indicator per run. Results The conventional biological Indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological Indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The Chemical Indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively. Conclusion The sensitivity of the Attest Rapid Readout parallels the conventional biological Indicators. These data suggest that a 60-minute rapid readout biological Indicator is equivalent to the 24-hour biological Indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical Indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.
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evaluation of a rapid readout biological Indicator for flash sterilization with three biological Indicators and three Chemical Indicators
Infection Control and Hospital Epidemiology, 1993Co-Authors: William A Rutala, Maria F Gergen, David J WeberAbstract:Objective: Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological Indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological Indicator that provides results within 60 minutes with three conventional, 24-hour biological Indicators for monitoring flash sterilization and three Chemical Indicators. Design: Conventional biological Indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout Indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical Indicators tested included Comply, Incheque, and Thermalog S. Survival at 132°C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56°C for the three conventional biological Indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological Indicator, and color change for the Chemical Indicators. Each exposure time was replicated four times with 10 of each biological and Chemical Indicator per run. Results: The conventional biological Indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological Indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The Chemical Indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively. Conclusion: The sensitivity of the Attest Rapid Readout parallels the conventional biological Indicators. These data suggest that a 60-minute rapid readout biological Indicator is equivalent to the 24-hour biological Indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical Indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.
Angus Cook - One of the best experts on this subject based on the ideXlab platform.
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recycled water potential health risks from volatile organic compounds and use of 1 4 dichlorobenzene as treatment performance Indicator
Water Research, 2012Co-Authors: Clemencia Rodriguez, Kathryn L Linge, Palenque Blair, Francesco Busetti, Brian Devine, Paul Van Buynder, Philip Weinstein, Angus CookAbstract:Abstract Characterisation of the concentrations and potential health risks of Chemicals in recycled water is important if this source of water is to be safely used to supplement drinking water sources. This research was conducted to: (i) determine the concentration of volatile organic compounds (VOCs) in secondary treated effluent (STE) and, post-reverse osmosis (RO) treatment and to; (ii) assess the health risk associated with VOCs for indirect potable reuse (IPR). Samples were examined pre and post-RO in one full-scale and one pilot plant in Perth, Western Australia. Risk quotients (RQ) were estimated by expressing the maximum and median concentration as a function of the health value. Of 61 VOCs analysed over a period of three years, twenty one (21) were detected in STE, with 1,4-dichlorobenzene (94%); tetrachloroethene (88%); carbon disulfide (81%) and; chloromethane (58%) most commonly detected. Median concentrations for these compounds in STE ranged from 0.81 μg/L for 1,4-dichlorobenzene to 0.02 μg/L for carbon disulphide. After RO, twenty six (26) VOCs were detected, of which 1,4-dichlorobenzene (89%); acrylonitrile (83%) chloromethane (63%) and carbon disulfide (40%) were the more frequently detected. RQ(max) were all below health values in the STE and after RO. Median removal efficiency for RO was variable, ranging from −77% (dichlorodifluoromethane) to 91.2% (tetrachloroethene). The results indicate that despite the detection of VOCs in STE and after RO, their human health impact in IPR is negligible due to the low concentrations detected. The results indicate that 1,4-dichlorobenzene is a potential treatment Chemical Indicator for assessment of VOCs in IPR using RO treatment.