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Fleck E, Keck C, Ryszka K, DeNatale E, Potkay J. Low-Viscosity Polydimethylsiloxane Resin for Facile 3D Printing of Elastomeric Microfluidics. MICROMACHINES 2023; 14:773. [PMID: 37421006 DOI: 10.3390/mi14040773] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/21/2023] [Accepted: 03/27/2023] [Indexed: 07/09/2023]
Abstract
Microfluidics is a rapidly advancing technology with expansive applications but has been restricted by slow, laborious fabrication techniques for polydimethylsiloxane (PDMS)-based devices. Currently, 3D printing promises to address this challenge with high-resolution commercial systems but is limited by a lack of material advances in generating high-fidelity parts with micron-scale features. To overcome this limitation, a low-viscosity, photopolymerizable PDMS resin was formulated with a methacrylate-PDMS copolymer, methacrylate-PDMS telechelic polymer, photoabsorber, Sudan I, photosensitizer, 2-isopropylthioxanthone, and a photoinitiator, 2,4,6-trimethyl benzoyl diphenylphosphine oxide. The performance of this resin was validated on a digital light processing (DLP) 3D printer, an Asiga MAX X27 UV. Resin resolution, part fidelity, mechanical properties, gas permeability, optical transparency, and biocompatibility were investigated. This resin produced resolved, unobstructed channels as small as 38.4 (±5.0) µm tall and membranes as thin as 30.9 (±0.5) µm. The printed material had an elongation at break of 58.6% ± 18.8%, Young's modulus of 0.30 ± 0.04 MPa, and was highly permeable to O2 (596 Barrers) and CO2 (3071 Barrers). Following the ethanol extraction of the unreacted components, this material demonstrated optical clarity and transparency (>80% transmission) and viability as a substrate for in vitro tissue culture. This paper presents a high-resolution, PDMS 3D-printing resin for the facile fabrication of microfluidic and biomedical devices.
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Affiliation(s)
- Elyse Fleck
- ECLS Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Charlise Keck
- ECLS Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Karolina Ryszka
- ECLS Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Emma DeNatale
- ECLS Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Joseph Potkay
- ECLS Laboratory, Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
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Rahmatnejad V, Tolosa M, Ge X, Rao G. A novel approach to noninvasive monitoring of dissolved carbon dioxide in small-scale cell culture processes. Front Bioeng Biotechnol 2022; 10:968294. [PMID: 36147535 PMCID: PMC9485895 DOI: 10.3389/fbioe.2022.968294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022] Open
Abstract
Disposable small-scale vessels are commonly used in cell culture studies in academia as well as early stages of bioprocess development. These types of research are crucial for our understanding about cells and bioprocesses as they provide important information regarding different parameters affecting cells. Dissolved carbon dioxide (DCO2) is one main parameter affecting cell metabolism. It is also an indicator of cell culture well-being. Despite CO2 being a critical process parameter, there is a lack of appropriate monitoring system for CO2 in small-scale vessels. Here, we present a membrane-based noninvasive method for measuring DCO2 in cell culture medium. The idea was achieved by modifying a T-flask and replacing a small area of it with CO2 permeable silicone membrane. In the proposed method, the concentration of CO2 dissolved in the cell culture medium is determined by measuring the initial diffusion rate of CO2 through a silicone membrane attached to the bottom wall of the T-flask. The measurement method was validated previously, and the efficacy of the noninvasive method was evaluated by growing E.coli, Pichia pastoris, and CHO cells in the proposed prototype. The results obtained from this method were verified with other quantitative data obtained from the process such as optical density (OD), cell density, dissolved oxygen (DO) and pH. The results show that the proposed membrane-based method is an effective way for completely noninvasive monitoring of DCO2 in small-scale cell culture processes. Additional diffusing species such as oxygen could also be measured using the same approach.
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Affiliation(s)
| | | | | | - Govind Rao
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD, United States
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Gartshore A, Kidd M, Joshi LT. Applications of Microwave Energy in Medicine. BIOSENSORS 2021; 11:96. [PMID: 33810335 PMCID: PMC8065940 DOI: 10.3390/bios11040096] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/17/2021] [Accepted: 03/22/2021] [Indexed: 05/17/2023]
Abstract
Microwaves are a highly utilized electromagnetic wave, used across a range of industries including food processing, communications, in the development of novel medical treatments and biosensor diagnostics. Microwaves have known thermal interactions and theorized non-thermal interactions with living matter; however, there is significant debate as to the mechanisms of action behind these interactions and the potential benefits and limitations of their use. This review summarizes the current knowledge surrounding the implementation of microwave technologies within the medical industry.
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Affiliation(s)
| | - Matt Kidd
- Emblation Microwave Ltd., Alloa, Scotland FK10 2HU, UK;
| | - Lovleen Tina Joshi
- School of Biomedical Science, University of Plymouth, Plymouth PL4 8AA, UK;
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Bell J, Alexander L, Carson J, Crossan A, McCaughan J, Mills H, O'Neill D, Moore JE, Millar BC. Nebuliser hygiene in cystic fibrosis: evidence-based recommendations. Breathe (Sheff) 2020; 16:190328. [PMID: 32684992 PMCID: PMC7341620 DOI: 10.1183/20734735.0328-2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/07/2020] [Indexed: 12/31/2022] Open
Abstract
Nebulised therapies are extensively used in the daily therapeutic management of cystic fibrosis both for mucociliary clearance and for the management of chronic infections. Extensive developments have been made in relation to nebulised drug delivery mechanisms and drug formulations, and guidelines have been prepared that have addressed the appropriate use of such therapies. However, due to these developments, a plethora of nebuliser devices and drug chambers exist, and frequently, the limited guidance provided in relation to nebuliser hygiene is to follow manufacturers' instructions. Such instructions are inconsistent and at times confusing, translating to an increase in the burden associated with nebuliser maintenance. An evidence-based universal guideline relating to nebuliser care and hygiene is urgently required that is applicable to both at-home use and inpatient use. This article reviews the scientific literature in order to propose an evidence-based approach to nebuliser hygiene to ensure optimum drug delivery, and infection prevention and control. EDUCATIONAL AIMS To understand the reasons why nebuliser hygiene is important.To give an overview of the current nebuliser care instructions that have been described by manufacturers, societies and the scientific literature.To outline the current nebuliser hygiene practices used by persons with cystic fibrosis in the home and hospital settings.To highlight areas that need further evaluation to promote optimum nebuliser care.To establish an evidence-based guideline for nebuliser hygiene in relation to cystic fibrosis.
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Affiliation(s)
- Jane Bell
- Northern Ireland Paediatric Cystic Fibrosis Centre, Dept of Physiotherapy, Royal Belfast Hospital for Sick Children, Belfast, UK
| | - Lauren Alexander
- Northern Ireland Paediatric Cystic Fibrosis Centre, Dept of Physiotherapy, Royal Belfast Hospital for Sick Children, Belfast, UK
| | - Jane Carson
- Northern Ireland Paediatric Cystic Fibrosis Centre, Dept of Physiotherapy, Royal Belfast Hospital for Sick Children, Belfast, UK
| | - Amanda Crossan
- Northern Ireland Regional Adult Cystic Fibrosis Centre, Belfast City Hospital, Belfast, UK
| | - John McCaughan
- Dept of Medical Microbiology, Royal Victoria Hospital, Belfast, UK
| | - Hazel Mills
- Northern Ireland Paediatric Cystic Fibrosis Centre, Dept of Physiotherapy, Royal Belfast Hospital for Sick Children, Belfast, UK
| | - Damian O'Neill
- Northern Ireland Regional Adult Cystic Fibrosis Centre, Belfast City Hospital, Belfast, UK
| | - John E. Moore
- Northern Ireland Regional Adult Cystic Fibrosis Centre, Belfast City Hospital, Belfast, UK
- Northern Ireland Public Health Laboratory, Dept of Bacteriology, Belfast City Hospital, Belfast, UK
| | - B. Cherie Millar
- Northern Ireland Regional Adult Cystic Fibrosis Centre, Belfast City Hospital, Belfast, UK
- Northern Ireland Public Health Laboratory, Dept of Bacteriology, Belfast City Hospital, Belfast, UK
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Chifflet S, Quéméneur M, Barani A, Angeletti B, Didry M, Grégori G, Pradel N. Impact of sterilization methods on dissolved trace metals concentrations in complex natural samples: Optimization of UV irradiation. MethodsX 2019; 6:1133-1146. [PMID: 31193445 PMCID: PMC6529719 DOI: 10.1016/j.mex.2019.04.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 04/18/2019] [Indexed: 11/27/2022] Open
Abstract
Sterilization is essential for discriminating biotic responses from abiotic reactions in laboratory experiments investigating biogeochemical processes of complex natural samples. However, the conventional methods used to effectively sterilize materials or culture media do not allow sterilizing complex natural samples while maintaining biogeochemical balances. The aim of this study was to develop a low-cost and easy-to-use method to obtain geochemically unmodified and sterilized samples from complex lacustrine or coastal marine ecosystems. In preliminary assays, the impact of several sterilization methods (autoclaving, chemical poisoning, microwave, UV irradiation) on the trace metals balances was studied using borosilicate glass (BG), fluorinated ethylene-propylene (FEP) or polyethylene terephthalate (PET) bottles. Unlike other methods, UV sterilization had minor effects on the distribution of dissolved trace metals. Additional tests using complex lacustrine and coastal marine samples under 10 g/L sediments were performed using a homemade UV sterilization chamber designed to simultaneously irradiate a large number samples. Results showed: •very reproducible UV tests in BG and FEP bottles•faster sterilization using FEP bottles than using BG bottles•low variations of dissolved trace metals concentrations, except for Al, Cu, Fe and Zn.
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Affiliation(s)
- Sandrine Chifflet
- Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Marianne Quéméneur
- Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Aude Barani
- Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Bernard Angeletti
- Aix Marseille Univ., CNRS-IRD-Collège de France, CEREGE UM34, 13545, Aix en Provence, France
| | - Morgane Didry
- Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Gérald Grégori
- Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Nathalie Pradel
- Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
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Saiman L, Siegel JD, LiPuma JJ, Brown RF, Bryson EA, Chambers MJ, Downer VS, Fliege J, Hazle LA, Jain M, Marshall BC, O’Malley C, Pattee SR, Potter-Bynoe G, Reid S, Robinson KA, Sabadosa KA, Schmidt HJ, Tullis E, Webber J, Weber DJ. Infection Prevention and Control Guideline for Cystic Fibrosis: 2013 Update. Infect Control Hosp Epidemiol 2016; 35 Suppl 1:S1-S67. [DOI: 10.1086/676882] [Citation(s) in RCA: 270] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The 2013 Infection Prevention and Control (IP&C) Guideline for Cystic Fibrosis (CF) was commissioned by the CF Foundation as an update of the 2003 Infection Control Guideline for CF. During the past decade, new knowledge and new challenges provided the following rationale to develop updated IP&C strategies for this unique population:1.The need to integrate relevant recommendations from evidence-based guidelines published since 2003 into IP&C practices for CF. These included guidelines from the Centers for Disease Control and Prevention (CDC)/Healthcare Infection Control Practices Advisory Committee (HICPAC), the World Health Organization (WHO), and key professional societies, including the Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA). During the past decade, new evidence has led to a renewed emphasis on source containment of potential pathogens and the role played by the contaminated healthcare environment in the transmission of infectious agents. Furthermore, an increased understanding of the importance of the application of implementation science, monitoring adherence, and feedback principles has been shown to increase the effectiveness of IP&C guideline recommendations.2.Experience with emerging pathogens in the non-CF population has expanded our understanding of droplet transmission of respiratory pathogens and can inform IP&C strategies for CF. These pathogens include severe acute respiratory syndrome coronavirus and the 2009 influenza A H1N1. Lessons learned about preventing transmission of methicillin-resistantStaphylococcus aureus(MRSA) and multidrug-resistant gram-negative pathogens in non-CF patient populations also can inform IP&C strategies for CF.
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Comparing the diel vertical migration of Karlodinium veneficum (dinophyceae) and Chattonella subsalsa (Raphidophyceae): PSII photochemistry, circadian control, and carbon assimilation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 143:107-19. [PMID: 25618815 DOI: 10.1016/j.jphotobiol.2014.12.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/06/2014] [Accepted: 12/18/2014] [Indexed: 11/23/2022]
Abstract
Diel vertical migration (DVM) is thought to provide an adaptive advantage to some phytoplankton, and may help determine the ecological niche of certain harmful algae. Here we separately compared DVM patterns between two species of harmful algae isolated from the Delaware Inland Bays, Karlodinium veneficum and Chattonella subsalsa, in laboratory columns. We interpreted the DVM patterns of each species with Photosystem II (PSII) photochemistry, rates of carbon assimilation, and specific growth rates. Each species migrated differently, wherein K. veneficum migrated closer to the surface each day with high population synchrony, while C. subsalsa migrated near to the surface from the first day of measurements with low population synchrony. Both species appeared to downregulate PSII in high light at the surface, but by different mechanisms. C. subsalsa grew slower than K. veneficum in low light intensities (≈bottom of columns), and exhibited maximal rates of C-assimilation (Pmax) at surface light intensities, suggesting this species may prefer high light, potentially explaining this species' rapid surface migration. Contrastingly, K. veneficum showed declines in carbon assimilation at surface light intensities, and exhibited a smaller reduction in growth at low (bottom) light intensities (compared to C. subsalsa), suggesting that this species' step-wise migration was photoacclimative and determined daily migration depth. DVM was found to be under circadian control in C. subsalsa, but not in K. veneficum. However, there was little evidence for circadian regulation of PSII photochemistry in either species. Migration conformed to each species' physiology, and the results contribute to our understanding each alga's realized environmental niche.
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Bagheri ZS, Giles E, El Sawi I, Amleh A, Schemitsch EH, Zdero R, Bougherara H. Osteogenesis and cytotoxicity of a new Carbon Fiber/Flax/Epoxy composite material for bone fracture plate applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 46:435-42. [PMID: 25492008 DOI: 10.1016/j.msec.2014.10.042] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 07/11/2014] [Accepted: 10/21/2014] [Indexed: 11/29/2022]
Abstract
This study is part of an ongoing program to develop a new CF/Flax/Epoxy bone fracture plate to be used in orthopedic trauma applications. The purpose was to determine this new plate's in-vitro effects on the level of bone formation genes, as well as cell viability in comparison with a medical grade metal (i.e. stainless steel) commonly employed for fabrication of bone plates (positive control). Cytotoxicity and osteogenesis induced by wear debris of the material were assessed using Methyl Tetrazolium (MTT) assay and reverse transcription polymerase chain reaction (RT-PCR) for 3 osteogenesis specific gene markers, including bone morphogenetic proteins (BMP2), runt-related transcription factor 2 (Runx2) and Osterix. Moreover, the Flax/Epoxy and CF/Epoxy composites were examined separately for their wettability properties by water absorption and contact angle (CA) tests using the sessile drop technique. The MTT results for indirect and direct assays indicated that the CF/Flax/Epoxy composite material showed comparable cell viability with no cytotoxicity at all incubation times to that of the metal group (p≥0.05). Osteogenesis test results showed that the expression level of Runx2 marker induced by CF/Flax/Epoxy were significantly higher than those induced by metal after 48 h (p=0.57). Also, the Flax/Epoxy composite revealed a hydrophilic character (CA=68.07°±2.05°) and absorbed more water up to 17.2% compared to CF/Epoxy, which reached 1.25% due to its hydrophobic character (CA=93.22°±1.95°) (p<0.001). Therefore, the new CF/Flax/Epoxy may be a potential candidate for medical applications as a bone fracture plate, as it showed similar cell viability with no negative effect on gene expression levels responsible for bone formation compared to medical grade stainless steel.
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Affiliation(s)
- Zahra S Bagheri
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON M5B-2K3, Canada; Martin Orthopaedic Biomechanics Lab, St. Michael's Hospital, Toronto, ON M5B-1W8, Canada
| | - Erica Giles
- Musculoskeletal Research Lab, St. Michael's Hospital, Toronto, ON M5B-1W8, Canada
| | - Ihab El Sawi
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON M5B-2K3, Canada
| | - Asma Amleh
- Department of Biology, The American University in Cairo (AUC), New Cairo 11835, Egypt
| | - Emil H Schemitsch
- Martin Orthopaedic Biomechanics Lab, St. Michael's Hospital, Toronto, ON M5B-1W8, Canada; Musculoskeletal Research Lab, St. Michael's Hospital, Toronto, ON M5B-1W8, Canada; Dept. of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON M5S-1A8, Canada
| | - Radovan Zdero
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON M5B-2K3, Canada; Martin Orthopaedic Biomechanics Lab, St. Michael's Hospital, Toronto, ON M5B-1W8, Canada; Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada
| | - Habiba Bougherara
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON M5B-2K3, Canada.
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Landrain T, Meyer M, Perez AM, Sussan R. Do-it-yourself biology: challenges and promises for an open science and technology movement. SYSTEMS AND SYNTHETIC BIOLOGY 2013; 7:115-26. [PMID: 24432149 DOI: 10.1007/s11693-013-9116-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 06/12/2013] [Accepted: 07/09/2013] [Indexed: 10/26/2022]
Abstract
The do-it-yourself biology (DIYbio) community is emerging as a movement that fosters open access to resources permitting modern molecular biology, and synthetic biology among others. It promises in particular to be a source of cheaper and simpler solutions for environmental monitoring, personal diagnostic and the use of biomaterials. The successful growth of a global community of DIYbio practitioners will depend largely on enabling safe access to state-of-the-art molecular biology tools and resources. In this paper we analyze the rise of DIYbio, its community, its material resources and its applications. We look at the current projects developed for the international genetically engineered machine competition in order to get a sense of what amateur biologists can potentially create in their community laboratories over the coming years. We also show why and how the DIYbio community, in the context of a global governance development, is putting in place a safety/ethical framework for guarantying the pursuit of its activity. And finally we argue that the global spread of DIY biology potentially reconfigures and opens up access to biological information and laboratory equipment and that, therefore, it can foster new practices and transversal collaborations between professional scientists and amateurs.
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Affiliation(s)
- Thomas Landrain
- Institute for Systems and Synthetic Biology, Genopole, Université d'Évry Val d'Essonne, CNRS, 91034 Évry, France ; Association La Paillasse, Paris Community Lab for Biotech, 75015 Paris, France
| | - Morgan Meyer
- Centre de Sociologie de l'Innovation, Ecole des Mines de Paris, Mines ParisTech, 75006 Paris, France
| | - Ariel Martin Perez
- Association La Paillasse, Paris Community Lab for Biotech, 75015 Paris, France
| | - Remi Sussan
- Association La Paillasse, Paris Community Lab for Biotech, 75015 Paris, France
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10
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Fang Y, Hu J, Xiong S, Zhao S. Effect of low-dose microwave radiation on Aspergillus parasiticus. Food Control 2011. [DOI: 10.1016/j.foodcont.2011.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Yu Y, Chan WI, Liao PH, Lo KV. Disinfection and solubilization of sewage sludge using the microwave enhanced advanced oxidation process. JOURNAL OF HAZARDOUS MATERIALS 2010; 181:1143-7. [PMID: 20591564 DOI: 10.1016/j.jhazmat.2010.05.134] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 04/07/2010] [Accepted: 05/30/2010] [Indexed: 05/09/2023]
Abstract
The microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was used to treat municipal sewage sludge for solids disintegration, nutrient solubilization, with an emphasis on pathogen destruction and regrowth. Pathogen reduction, in terms of fecal coliform concentrations were found below detection limit (1000 CFU/L) immediately after treatment when sludge was treated at 70 degrees C with more than 0.04% of H(2)O(2) (w/w). Significant regrowth of fecal coliforms was observed for the treated samples after 72 h. However, no regrowth was observed for samples treated at 70 degrees C with 0.08% H(2)O(2) or higher, suggesting a complete elimination of fecal coliforms. The range of hydrogen peroxide used did not have a significant effect on orthophosphate release regardless of temperature. Ammonia release at these low temperatures was found to be insignificant. The soluble chemical oxygen demand increased with an increase of hydrogen peroxide dosage at 70 degrees C. However, there was no clear trend of soluble chemical oxygen demand over varying hydrogen peroxide dosage at 55 degrees C. The MW/H(2)O(2)-AOP is a novel process for the pasteurization and stabilization of sewage sludge to meet and maintain Class A biosolids criteria.
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Affiliation(s)
- Y Yu
- Department of Civil Engineering, University of British Columbia, Vancouver, BC, Canada
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12
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Ribeiro DG, Pavarina AC, Dovigo LN, Palomari Spolidorio DM, Giampaolo ET, Vergani CE. Denture disinfection by microwave irradiation: a randomized clinical study. J Dent 2009; 37:666-72. [PMID: 19481327 DOI: 10.1016/j.jdent.2009.04.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 04/16/2009] [Accepted: 04/24/2009] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE This study evaluated the clinical effectiveness of two exposure times of microwave irradiation on the disinfection of complete dentures. METHODS Biofilm samples were collected from dentures of 30 patients, who were randomly divided into two experimental groups of 15 subjects each: Group 1-patients had their maxillary denture microwaved for 3 min (650W); Group 2-patients had their maxillary denture microwaved for 2 min (650W). Denture biofilm samples were taken with swabs, before (left side surfaces) and after (right side surfaces) microwave irradiation. All microbial material was plated on selective media for Candida spp., Staphylococcus spp., mutans streptococci and a non-selective media. After incubation (48 h/37 degrees C), the number of colony-forming units (cfu/mL) was counted. Microorganisms which grew on selective media were identified using biochemical methods. The data were statistically analyzed by Kruskal-Wallis test, followed by Dunn's post-test (alpha=0.05). RESULTS Microwave irradiation for 3 min (Group 1) resulted in sterilization of all dentures evaluated. After microwave irradiation for 2 min (Group 2), a significant decrease in Candida spp. (P=0.0062), Staphylococcus spp. (P=0.0178), mutans streptococci (P=0.0047) and non-identified species (P<0.0001) was achieved in comparison with the cfu/mL obtained before irradiation. The colonies grown after 2 min of microwave irradiation were identified as Candida albicans, non-aureus Staphylococci and Streptococcus mutans. CONCLUSION Microwave irradiation for 3 min may be a potential treatment to prevent cross-contamination.
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Affiliation(s)
- Daniela Garcia Ribeiro
- R. Humaitá n degrees 1680, CEP 14801-903, Department of Dental Materials and Prosthodontics, São Paulo State University, UNESP, Araraquara Dental School, Araraquara, São Paulo, Brazil
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Abstract
In this article, the authors outline some of the major historical events that signaled the need to better understand mechanisms of infection in cystic fibrosis (CF). The authors discuss general principles of infection control, focusing on issues of particular importance to patients who have CF. The authors also describe the major pathogens associated with the CF airway, provide a review of findings from inpatient and outpatient studies of infection control, and provide an outline of future directions for investigation.
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Affiliation(s)
- Jonathan B Zuckerman
- Department of Medicine, The University of Vermont College of Medicine, E-126 Given Building, 89 Beaumont Avenue, Burlington, VT 05405-0068, USA.
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Takashima H, Miyakawa Y, Kanno Y. Microwave sterilization with metal thin film coated catalyst in liquid phase. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2007. [DOI: 10.1016/j.msec.2006.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Webb BC, Thomas CJ, Whittle T. A 2-year study of Candida-associated denture stomatitis treatment in aged care subjects. Gerodontology 2005; 22:168-76. [PMID: 16163908 DOI: 10.1111/j.1741-2358.2005.00065.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To test the efficacy of two methods of treatment for denture stomatitis in aged care institutions. BACKGROUND DATA Candida-associated denture stomatitis has been associated with a lack of denture hygiene. MATERIALS AND METHODS Sixty subjects with denture stomatitis were randomly divided into three groups: sodium hypochlorite denture soak, microwaving and control. Both methods of treatment were carried out on a nightly basis for 1 week, excepting the control group. Standardised photographs of the palate and microbial samples of palate, upper and lower dentures were taken before and after treatment. RESULTS Both hypochlorite and microwave irradiation significantly reduced the numbers of Candida and aerobic bacteria on both dentures and both methods significantly reduced Candida on the palate. However, palatal aerobic bacteria were not significantly reduced by either method and the controls showed insignificant changes at all three sites for both Candida and aerobes. CONCLUSION While both methods of denture disinfection were successful, except for the counts of palatal aerobic bacteria, three independent observers of the clinical photographs had difficulty in identifying the controls but were more successful with the treatments. The raters also showed that there was no difference between both methods of disinfection and this agreed with the microbiological analysis.
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Affiliation(s)
- Bettine C Webb
- Faculty of Dentistry, The University of Sydney, Sydney, Australia.
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Kiat-amnuay S, Johnston DA, Powers JM, Jacob RF. Color Stability of Dry Earth Pigmented Maxillofacial Silicone A-2186 Subjected to Microwave Energy Exposure. J Prosthodont 2005; 14:91-6. [PMID: 16011619 DOI: 10.1111/j.1532-849x.2005.00017.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The purpose of this study was to measure spectrophotometrically the color stability of pigmented A-2186 silicone maxillofacial elastomer with 10% by volume of titanium white dry earth opacifier before and after exposure to microwave energy over a simulated 1.5-year period of microwave sterilization. MATERIALS AND METHODS A-2186 silicone elastomer opacified with titanium white dry earth pigment, pigmented with 5 cosmetic dry earth pigment colors [no pigment (control) group (Pc), red (Pr), yellow ochre (Py), burnt sienna (Po), and a mixture of Pr + Py + Po color group (P3)], was used in this study. Each of the 5 experimental groups consisted of 5 specimens. All specimens were placed in a 250 ml glass beaker filled with 150 ml of water (replenished for each microwave exposure). An exposure of 6 minutes was used 18 times (simulating 1.5 years of microwave sterilization with one 6 minute exposure monthly). Reflectance values were measured by spectrophotometer. Three- and two-way analyses of variance with repeated measures were performed for the color difference (DeltaE*) with the factors of group/color/months, and group/months, respectively. Means were compared by Tukey Honest Significant Difference (HSD) multiple range test calculated at the 0.05 level of significance using SPSS. RESULTS The trained human eye can detect color changes (DeltaE*) greater than 1.0. Most DeltaE* values of the red pigment group at all intervals and the mixed pigment group at 15- and 18- month intervals increased significantly greater than 1.0 (p < 0.001) compared with the control group. Yellow and burnt sienna groups remained the most color stable over time with DeltaE* values below 0.35. CONCLUSIONS Lack of color stability of red dry earth pigmented A-2186 silicone maxillofacial elastomers was clinically significant after 12-month exposure to microwave energy as compared with yellow, burnt sienna, and opacified A-2186 dry earth pigments.
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Affiliation(s)
- Sudarat Kiat-amnuay
- Department of Restorative Dentistry and Biomaterials, The University of Texas Dental Branch at Houston, Houston, TX 77030, USA.
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Abstract
Over the past 20 years there has been a greater interest in infection control in cystic fibrosis (CF) as patient-to-patient transmission of pathogens has been increasingly demonstrated in this unique patient population. The CF Foundation sponsored a consensus conference to craft recommendations for infection control practices for CF care providers. This review provides a summary of the literature addressing infection control in CF. Burkholderia cepacia complex, Pseudomonas aeruginosa, and Staphylococcus aureus have all been shown to spread between patients with CF. Standard precautions, transmission-based precautions including contact and droplet precautions, appropriate hand hygiene for health care workers, patients, and their families, and care of respiratory tract equipment to prevent the transmission of infectious agents serve as the foundations of infection control and prevent the acquisition of potential pathogens by patients with CF. The respiratory secretions of all CF patients potentially harbor clinically and epidemiologically important microorganisms, even if they have not yet been detected in cultures from the respiratory tract. CF patients should be educated to contain their secretions and maintain a distance of >3 ft from other CF patients to avoid the transmission of potential pathogens, even if culture results are unavailable or negative. To prevent the acquisition of pathogens from respiratory therapy equipment used in health care settings as well as in the home, such equipment should be cleaned and disinfected. It will be critical to measure the dissemination, implementation, and potential impact of these guidelines to monitor changes in practice and reduction in infections.
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Affiliation(s)
- Lisa Saiman
- Department of Pediatrics, Columbia University, New York, New York 10032, USA.
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Hong SM, Park JK, Lee YO. Mechanisms of microwave irradiation involved in the destruction of fecal coliforms from biosolids. WATER RESEARCH 2004; 38:1615-25. [PMID: 15016539 DOI: 10.1016/j.watres.2003.12.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2003] [Revised: 11/20/2003] [Accepted: 12/09/2003] [Indexed: 05/22/2023]
Abstract
Microwaves have been found to be effective in destructing pathogens in sewage sludge (biosolids) (75th Annual Water Environment Federation Conference, Chicago, September 29-October 2, 2002; Third World Water Congress, International Water Association, Melbourne, Australia, April 7-12, 2002). Mechanisms and roles of microwaves on fecal coliform destruction were investigated using bacterial viability tests, electron transport system (ETS) and beta-galactosidase activity assays, gel electrophoresis, and genomic deoxyribonucleic acid (DNA) optical density (OD) measurements with fecal coliforms isolated from biosolids. Bacterial viability tests demonstrated cell membrane damage as microwave irradiation intensity and temperature increased. Above 60+/-3 degrees C, viable cells were rarely found when pure fecal coliforms were irradiated with microwaves. ETS and beta-galactosidase activity assays revealed increased activity for externally heated samples due to fecal coliform growth but decreased activity for microwave-irradiated samples as temperature was increased from 20 degrees C to 57 degrees C, indicating other destruction mechanisms besides heating. Between 57 degrees C and 68 degrees C, microwave irradiation led to a more rapid decrease in activity than external heating by convection. Above 68 degrees C, bacterial activity almost ceased for both pretreatments. DNA bands in gel electrophoresis tests and OD of genomic DNA decreased more rapidly for microwave-irradiated samples than for externally heated samples, implying that microwaves disrupted DNA in fecal coliform cells at lower temperatures than external heating. Microwave irradiation of sludge appears to be a viable and economical method of destructing pathogens and generating environmentally safe sludge.
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Affiliation(s)
- Seung M Hong
- Daewoo Environmental Technology Research Center, Soowon, South Korea
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19
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Dunsmuir RA, Gallacher G. Microwave sterilization of femoral head allograft. J Clin Microbiol 2003; 41:4755-7. [PMID: 14532216 PMCID: PMC254296 DOI: 10.1128/jcm.41.10.4755-4757.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2003] [Revised: 03/24/2003] [Accepted: 07/03/2003] [Indexed: 12/30/2022] Open
Abstract
The potential shortage of allograft bone has led to the need to investigate other sources of bone for allografts. Some allograft bone donated from primary total hip arthroplasty recipients must be discarded or treated to become usable as a result of bacterial contamination. Femoral head allografts were contaminated with Staphylococcus aureus and Bacillus subtilis. A domestic microwave oven was used. The contaminated bone was exposed to microwave irradiation for different time periods. The samples were then cultured to attempt to grow the two bacterial species. The contaminated bone samples failed to grow any organisms after 2 min of exposure to microwave irradiation. This study shows that sterilization of femoral head allografts contaminated with S. aureus and B. subtilis can be achieved with microwave irradiation in a domestic microwave oven. This method of sterilization of bone allografts is cheap, easily used, and an effective way to process contaminated bone.
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Affiliation(s)
- Robert A Dunsmuir
- Department of Orthopaedics, Southern General Hospital, Glasgow, United Kingdom.
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20
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Saiman L, Siegel J. Infection control recommendations for patients with cystic fibrosis: microbiology, important pathogens, and infection control practices to prevent patient-to-patient transmission. Infect Control Hosp Epidemiol 2003; 24:S6-52. [PMID: 12789902 DOI: 10.1086/503485] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Infection Control Recommendations for Patients With Cystic Fibrosis: Microbiology, Important Pathogens, and Infection Control Practices to Prevent Patient-to-Patient Transmissionupdates, expands, and replaces the consensus statement,Microbiology and Infectious Disease in Cystic Fibrosispublished in 1994. This consensus document presents background data and evidence-based recommendations for practices that are intended to decrease the risk of transmission of respiratory pathogens among CF patients from contaminated respiratory therapy equipment or the contaminated environment and thereby reduce the burden of respiratory illness. Included are recommendations applicable in the acute care hospital, ambulatory, home care, and selected non-healthcare settings. The target audience includes all healthcare workers who provide care to CF patients. Antimicrobial management is beyond the scope of this document.
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Affiliation(s)
- Lisa Saiman
- Department of Pediatrics, Columbia University, New York, New York, USA
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21
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Abstract
Strains representing four types of common heat-resistant spores of Bacillus spp., B. cereus CCRC 14655, B. coagulans CCRC10606, B. licheniformis CCRC14693, and B. subtilis CCRC14199, were heated with microwaves at different power levels and under different conditions in salt solutions, starch solutions, and containers. The results of this study showed that B. licheniformis spores had the highest microwave tolerance at a power level of 100% for different incubation times. B. coagulans spores showed the lowest microwave tolerance in salt solutions with water activity values of 0.6, 0.7, 0.8, and 0.9, and B. licheniformis spores were the most resistant in the tested salt solutions at different incubation times. An analysis of the effect of the viscosity of the medium revealed that the bacteria had the lowest microwave resistance in a medium containing <0.8% starch in solution. The microwave resistance levels of the test microorganisms were the lower in glass containers than in polypropylene containers and aluminum foil-enclosed pouches. Of the four species of bacilli, B. licheniformis had the highest microwave tolerance (P < 0.05) under all conditions.
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Affiliation(s)
- Jinn-Chyi Wang
- Department of Food Science and Technology, Tajen Institute of Technology, 20, Wei-Shin Road, Shin-Erh Village, Yen-Pu Hsing, Ping Tung, Taiwan.
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Webb BC, Thomas CJ, Willcox MD, Harty DW, Knox KW. Candida-associated denture stomatitis. Aetiology and management: a review. Part 3. Treatment of oral candidosis. Aust Dent J 1998; 43:244-9. [PMID: 9775471 DOI: 10.1111/j.1834-7819.1998.tb00172.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Treatment of oral candidosis with topical antifungal agents such as nystatin and amphotericin B is effective initially. However, medication can produce side effects in some patients and when therapy is stopped the condition can recur. Alternative treatment involving the use of antiseptics and disinfecting agents has been shown to play an important role in the control of dental plaque. The use of sodium hypochlorite as an overnight denture soak has been shown to eliminate denture plaque and recent investigations have demonstrated that microwave irradiation of dentures at a specified setting and exposure time is bactericidal and candidacidal.
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Affiliation(s)
- B C Webb
- Institute of Dental Research, Sydney
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23
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Abstract
The killing activity of microwaves of 2450 MHz frequency and 600 W power on Pseudomonas aeruginosa, Escherichia coli, Enterobacter sakazakii, Klebsiella pneumoniae, Staphylococcus aureus, Candida albicans, Mycobacterium terrae and poliomyelitis vaccine-virus suspended in five infant formula preparations was investigated. The samples were brought to the boil (85-100 s depending on milk type). They had reached average temperatures of 82-93 degrees C at this point. Most of the vegetative organisms were killed. In those samples where growth was still detectable after microwave treatment, a significant reduction in viable micro-organisms (at least 5000-fold) was noted. We conclude that microwave beating to the boil is a convenient and fast method to reduce microbial contamination of infant feeds. However, care should be taken to ensure that milk is adequately cooled to the required temperature before it is fed to an infant.
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Affiliation(s)
- G Kindle
- Institute of Environmental Medicine and Hospital Epidemiology, Freiburg, Germany
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Kakita Y, Kashige N, Murata K, Kuroiwa A, Funatsu M, Watanabe K. Inactivation of Lactobacillus bacteriophage PL-1 by microwave irradiation. Microbiol Immunol 1995; 39:571-6. [PMID: 7494495 DOI: 10.1111/j.1348-0421.1995.tb02244.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The effect of microwave irradiation on the survival of bacteriophage PL-1, which is specific for Lactobacillus casei, was studied using a commercial 2,450 MHz microwave oven. The phages were inactivated by microwave irradiation according to almost first-order reaction kinetics. The rate of phage inactivation was not affected by the difference in the continuous or intermittent irradiation, nor by the concentrations of phages used, but was affected by the volume of phage suspensions, which prevented the loss of generated heat. Microwave irradiation of phage suspensions produced a number of ghost phages with empty heads, but fragmentation of the tail was hardly noticed. The breakage of phage genome DNA was primarily caused by the heat generated by microwave irradiation, whereas the phage DNA was not affected by the same temperature achieved by heat from outside. Thus we concluded that the phage-inactivating effect of microwave irradiation was mainly attributed to a thermal microwave effect, which was much stronger than a simple thermal exposure.
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Affiliation(s)
- Y Kakita
- Faculty of Pharmaceutical Sciences, School of Medicine, Fukuoka University, Japan
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Rosaspina S, Salvatorelli G, Anzanel D. The bactericidal effect of microwaves on Mycobacterium bovis dried on scalpel blades. J Hosp Infect 1994; 26:45-50. [PMID: 7910182 DOI: 10.1016/0195-6701(94)90078-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The action of microwaves on stainless steel scalpel blades contaminated with Mycobacterium bovis was investigated. The complete destruction of M. bovis was obtained with 4 min of microwave exposure. When the preparations were subjected to scanning electron microscopy, the bacteria had undergone a progressive series of alterations consisting, initially, of the formation of deep pits in the bacterial body and eventually the complete disintegration of the microorganisms. Such phenomena are less evident when this mycobacterium is exposed to other sterilization methods such as dry heat or autoclaving.
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Affiliation(s)
- S Rosaspina
- Department of Cytology and Histology, University of Ferrara, Italy
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26
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Najdovski L, Dragas AZ, Kotnik V. The killing activity of microwaves on some non-sporogenic and sporogenic medically important bacterial strains. J Hosp Infect 1991; 19:239-47. [PMID: 1686036 DOI: 10.1016/0195-6701(91)90241-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The killing activity of microwaves of 2450 MHz frequency and 325 W, 650 W and 1400 W power on some bacterial strains was investigated. Vegetative strains of Staphylococcus aureus, Streptococcus pyogenes Group A, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis and spores of Bacillus subtilis and Bacillis stearothermophilus in aqueous suspensions were exposed to 325 W and 650 W waves for different lengths of time. Enterococcus faecalis and spores of B. subtilis and B. stearothermophilus were exposed additionally to 1400 W waves in aqueous and 'dried' suspensions. Vegetative bacteria were promptly killed in 5 min or less, E. faecalis being slightly more resistant. Bacterial spores were only killed in aqueous suspension when a 1400 W setting was used for 10 to 20 min. Bacterial spores adhering to the tube walls after the aqueous suspension was poured out were reduced in number. We assume that the conventional microwave ovens available on the market may be used for a high level of disinfection but not for sterilization, and only then if sufficient water is present.
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Affiliation(s)
- L Najdovski
- Institute of Microbiology, Medical Faculty, University of Ljubljana, Slovenia, Yugoslavia
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27
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Abstract
A method is presented for the successful decontamination of sparingly soluble pteridine derivatives by microwave irradiation. The method is nondestructive, rapid and effective in eliminating contamination.
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Affiliation(s)
- A Alam
- Bio-Kalfs - Research & Development, Birmingham, England, United Kingdom
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Husson van Vliet J. Microwave radiation: a useful fixation method for viral vaccine quantitation. J Virol Methods 1991; 32:139-48. [PMID: 1874912 DOI: 10.1016/0166-0934(91)90044-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
As an alternative to the formalin fixation of cells before staining, microwave irradiation was found a very advantageous fixation procedure in viral vaccine quantitation assays. The use of microwaves allows to avoid dangerous chemicals and thereby reduces time and equipment.
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Affiliation(s)
- J Husson van Vliet
- Institut d'Hygiène et d'Epidémiologie, Département Microbiologie, Brussels, Belgium
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30
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Matos LDSS. Esterilização de alimentos por microondas para pacientes receptores de transplante de medula. Rev Bras Enferm 1990. [DOI: 10.1590/s0034-71671990000100019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Receptores de transplante de medula apresentam inúmeros problemas gastrointestinais que interferem com uma adequada ingestão oral. Estudos prévios mostram que o ambiente com fluxo laminar, dieta estéril, descontaminação oral com antibióticos e limpeza da pele são fatores significantes na prevenção da infecção. A literatura recomenda a esterilização dos alimentos por autoclagem, irradiação ou forno. Nesse trabalho propõe-se a esterilização por microondas, por ser um processo rápido, seguro e não alterar o aspecto e sabor dos alimentos.
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Douglas C, Burke B, Kessler DL, Cicmanec JF, Bracken RB. Microwave: practical cost-effective method for sterilizing urinary catheters in the home. Urology 1990; 35:219-22. [PMID: 2107618 DOI: 10.1016/0090-4295(90)80035-l] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We used a standard microwave oven to sterilize red rubber catheters used for intermittent self-catheterization. Catheters were incubated for sixty minutes in a suspension of microorganisms isolated from the urine of patients with urinary tract infections. For each trial, 6 catheters were removed from their respective suspensions, placed in separate plastic freezer bags, distributed evenly in a microwave oven (avoiding cold spots), and microwaved simultaneously for twelve minutes. A control catheter was not microwaved. Two strains of each microorganism were tested. The urinary isolates were Escherichia coli, Klebsiella sp., Proteus sp., Enterobacter sp., Pseudomonas sp., Streptococcus sp., Staphylococcus sp., and Candida sp. In each experiment, all 6 catheters were sterilized. Repeat sterilization in the microwave oven did not affect the integrity of the catheters or the plastic bags. A water heat sink of constant volume was employed. A home microwave oven may be used as a method to sterilize red rubber catheters for reuse with a recommended time of twelve minutes at full power. This technique makes aseptic intermittent self-catheterization a practical possibility.
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Affiliation(s)
- C Douglas
- Department of Surgery, University of Cincinnati Medical Center, Ohio
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32
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Silbar EC, Cicmanec JF, Burke BM, Bracken RB. Microwave sterilization: a method for home sterilization of urinary catheters. J Urol 1989; 141:88-90. [PMID: 2908961 DOI: 10.1016/s0022-5347(17)40599-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A standard microwave oven has been used to sterilize catheters used for intermittent self-catheterization. Catheters were incubated for 60 minutes in a suspension of microorganisms isolated from the urine of patients with urinary tract infections. Each catheter was removed from the suspension, placed in a paper bag and microwaved for 0 to 30 minutes. A control catheter was not microwaved. We tested 42 strains of microorganisms to determine the minimum microwaving time needed to sterilize the catheters. Representative urinary isolates of Escherichia coli, and Klebsiella, Proteus, Enterobacter, Pseudomonas, Staphylococcus, Streptococcus and Candida species were tested. Mean sterilization time for all strains was 13.0 minutes (standard deviation +/- 5.7 minutes), with a range of 4.0 to 28.6 minutes. Repeat sterilization in the microwave oven did not affect the integrity of the catheter. A water heat sink of constant volume was required. A home microwave oven may be used as a method to sterilize red rubber catheters for reuse. This technique makes aseptic intermittent self-catheterization a practical possibility.
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Affiliation(s)
- E C Silbar
- Department of Surgery, University of Cincinnati Medical Center, Ohio
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Abstract
This study has shown that representative fungi, viruses, and aerobic and anaerobic bacteria, including spore formers, can easily be killed in a conventional microwave oven with proper modifications. Metal instruments, including air turbine handpieces and burs, and acrylic dentures can be sterilized in short periods. Consistent sterilization can be accomplished only if the items to be sterilized are rotated in a three-dimensional manner throughout the microwave cavity. Arcing back to the magnetron and damage to the microwave oven are prevented by placing a radar absorbent material within the oven and with proper insulation of the item to be sterilized.
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Beltrán-Langarica A, López-Contreras D, Kuri-Harcuch W. A simple procedure for washing and sterilizing plastic tissue culture dishes for reuse. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/bf01665881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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