Ultraviolet radiation for the sterilization of contact lenses

International Nuclear Information System (INIS)

Gritz, D.C.; Lee, T.Y.; McDonnell, P.J.; Shih, K.; Baron, N.

1990-01-01

Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study

Fluorescent-light-induced lethality and DNA repair in normal and xeroderma pigmentosum fibroblasts

International Nuclear Information System (INIS)

Ritter, M.A.; Williams, J.R.

1981-01-01

Cell survival and induction of endonuclease-sensitive sites in DNA were measured in human fibroblast cells exposed to fluorescent light or germicidal ultraviolet light. Cells from a xeroderma pigmentosum patient were hypersensitive to cell killing by fluorescent light, although less so than for germicidal ultraviolet light. Xeroderma pigmentosum cells were deficient in the removal of fluorescent light-induced endonuclease sites that are probably pyrimidine dimers, and both the xeroderma pigmentosum and normal cells removed these sites with kinetics indistinguishable from those for ultraviolet light-induced sites. A comparison of fluorescent with ultraviolet light data demonstrates that there are markedly fewer pyrimidine dimers per lethal event for fluorescent than for ultraviolet light, suggesting a major role for non-dimer damage in fluorescent lethality. (Auth.)

phytoremediation of sewage sludge in soils contaminated

African Journals Online (AJOL)

PROF EKWUEME

repeated increase daily or weekly application of sewage ... fertilizers, herbicides, germicides and decomposition and burning of fossil fuels. ... However, organic and inorganic pollutants greatly ... green vegetables for the in-situ or ex-situ.

Feasibility of a combined carrier test for disinfectants: studies with a mixture of five types of microorganisms.

Science.gov (United States)

Best, M; Springthorpe, V S; Sattar, S A

1994-06-01

There is mounting concern regarding the efficacy of many germicides on the market because officially recognized germicidal tests for various classes of microorganisms vary widely and often lack reproducibility and proper quantitation. We report here a carrier method for simultaneously and quantitatively assessing the efficacy of liquid chemical germicides against a mixture of microorganisms of varying degrees of resistance. In the test, each small glass cup (10 mm wide x 14 mm long) was contaminated with 10 microliters of a standardized mixture of Staphylococcus aureus, Mycobacterium bovis bacille Calmette-Guérin, Trichophyton mentagrophytes spores, Sabin poliovirus type 1, and Bacillus stearothermophilus spores in 5% fetal bovine serum. The inoculum was dried for 60 minutes under ambient conditions and covered with 60 microliters of the disinfectant under test or a balanced salt solution control for the desired contact time. The carrier was then placed in 2940 microliters of an eluent and the eluates assayed separately for the five microorganisms. Tap water was used to dilute the test product as needed. Of the 11 products tested, 2% alkaline glutaraldehyde, 0.6% sodium hypochlorite (about 5000 ppm free chlorine), and a 0.4% quarternary ammonium compound containing 23% hydrochloric acid were effective against all five challenge organisms. A hard-surface spray containing 0.1% o-phenylphenol with 79% ethanol was effective against all but bacterial spores; 70% (volume/volume) ethanol alone and povidone-iodine (1% available iodine) were effective against S. aureus, the mycobacterium, and the fungus; a 3% solution of peroxygen compounds was effective only against S. aureus and the poliovirus; 1.5% chlorhexidine gluconate, 0.06% quaternary ammonia compound, and 0.03% o-phenylphenol + 0.03% p-tertiary amylphenol could inactivate nothing but S. aureus; and 3% hydrogen peroxide was ineffective in all tests. This method shows promise for use with various classes of

207-nm UV Light-A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. II: In-Vivo Safety Studies.

Science.gov (United States)

Buonanno, Manuela; Stanislauskas, Milda; Ponnaiya, Brian; Bigelow, Alan W; Randers-Pehrson, Gerhard; Xu, Yanping; Shuryak, Igor; Smilenov, Lubomir; Owens, David M; Brenner, David J

2016-01-01

UVC light generated by conventional germicidal lamps is a well-established anti-microbial modality, effective against both bacteria and viruses. However, it is a human health hazard, being both carcinogenic and cataractogenic. Earlier studies showed that single-wavelength far-UVC light (207 nm) generated by excimer lamps kills bacteria without apparent harm to human skin tissue in vitro. The biophysical explanation is that, due to its extremely short range in biological material, 207 nm UV light cannot penetrate the human stratum corneum (the outer dead-cell skin layer, thickness 5-20 μm) nor even the cytoplasm of individual human cells. By contrast, 207 nm UV light can penetrate bacteria and viruses because these cells are physically much smaller. To test the biophysically-based hypothesis that 207 nm UV light is not cytotoxic to exposed mammalian skin in vivo. Hairless mice were exposed to a bactericidal UV fluence of 157 mJ/cm2 delivered by a filtered Kr-Br excimer lamp producing monoenergetic 207-nm UV light, or delivered by a conventional 254-nm UV germicidal lamp. Sham irradiations constituted the negative control. Eight relevant cellular and molecular damage endpoints including epidermal hyperplasia, pre-mutagenic UV-associated DNA lesions, skin inflammation, and normal cell proliferation and differentiation were evaluated in mice dorsal skin harvested 48 h after UV exposure. While conventional germicidal UV (254 nm) exposure produced significant effects for all the studied skin damage endpoints, the same fluence of 207 nm UV light produced results that were not statistically distinguishable from the zero exposure controls. As predicted by biophysical considerations and in agreement with earlier in vitro studies, 207-nm light does not appear to be significantly cytotoxic to mouse skin. These results suggest that excimer-based far-UVC light could potentially be used for its anti-microbial properties, but without the associated hazards to skin of conventional

207-nm UV Light—A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. II: In-Vivo Safety Studies

Science.gov (United States)

Buonanno, Manuela; Stanislauskas, Milda; Ponnaiya, Brian; Bigelow, Alan W.; Randers-Pehrson, Gerhard; Xu, Yanping; Shuryak, Igor; Smilenov, Lubomir; Owens, David M.; Brenner, David J.

2016-01-01

Background UVC light generated by conventional germicidal lamps is a well-established anti-microbial modality, effective against both bacteria and viruses. However, it is a human health hazard, being both carcinogenic and cataractogenic. Earlier studies showed that single-wavelength far-UVC light (207 nm) generated by excimer lamps kills bacteria without apparent harm to human skin tissue in vitro. The biophysical explanation is that, due to its extremely short range in biological material, 207 nm UV light cannot penetrate the human stratum corneum (the outer dead-cell skin layer, thickness 5–20 μm) nor even the cytoplasm of individual human cells. By contrast, 207 nm UV light can penetrate bacteria and viruses because these cells are physically much smaller. Aims To test the biophysically-based hypothesis that 207 nm UV light is not cytotoxic to exposed mammalian skin in vivo. Methods Hairless mice were exposed to a bactericidal UV fluence of 157 mJ/cm2 delivered by a filtered Kr-Br excimer lamp producing monoenergetic 207-nm UV light, or delivered by a conventional 254-nm UV germicidal lamp. Sham irradiations constituted the negative control. Eight relevant cellular and molecular damage endpoints including epidermal hyperplasia, pre-mutagenic UV-associated DNA lesions, skin inflammation, and normal cell proliferation and differentiation were evaluated in mice dorsal skin harvested 48 h after UV exposure. Results While conventional germicidal UV (254 nm) exposure produced significant effects for all the studied skin damage endpoints, the same fluence of 207 nm UV light produced results that were not statistically distinguishable from the zero exposure controls. Conclusions As predicted by biophysical considerations and in agreement with earlier in vitro studies, 207-nm light does not appear to be significantly cytotoxic to mouse skin. These results suggest that excimer-based far-UVC light could potentially be used for its anti-microbial properties, but without

Power supply improvements for ballasts-low pressure mercury/argon discharge lamp for water purification

Science.gov (United States)

Bokhtache, A. Aissa; Zegaoui, A.; Djahbar, A.; Allouache, H.; Hemici, K.; Kessaissia, F. Z.; Bouchrit, M. S.; Aillerie, M.

2017-02-01

The low-pressure electrical discharges established in the mercury rare gas mixtures are the basis of many applications both in the field of lighting and for industrial applications. In order to select an efficient high frequency power supply (ECG -based PWM inverter), we present and discuss results obtained in the simulation of three kinds of power supplies delivering a 0.65 A - 50KHz sinusoidal current dedicated to power low pressure UV Mercury - Argon lamp used for effect germicide on water treatment thus allowing maximum UVC radiation at 253.7 nm. Three ballasts half-bridge configurations were compared with criteria based on resulting germicide efficiency, electrical yield and reliability, for example the quality of the sinusoidal current with reduced THD, and finally, we also considered in this analysis the final economic aspect.

21 CFR 74.1339 - D&C Red No. 39.

Science.gov (United States)

2010-04-01

.... Anthranilic acid, not more than 0.2 percent. N,N-(β,β′-Dihydroxy-diethyl) aniline, not more than 0.2 percent... germicidal solutions intended for external application only, and subject to the further restriction that the...

Surface sterilization by low energy electron beams

International Nuclear Information System (INIS)

Sekiguchi, Masayuki; Tabei, Masae

1989-01-01

The germicidal effectiveness of low energy electron beams (175 KV) against bacterial cells was investigated. The dry spores of Bacillus pumilus ATCC 27142 and Bacillus globigii ATCC 9372 inoculated on carrier materials and irradiated by gamma rays showed the exponential type of survival curves whereas they showed sigmoidal ones when exposed to low energy electron beams. When similarly irradiated, the wet spores inoculated on membrane filter showed the same survival curves as the dry spores inoculated on carrier materials. The wet vegetative cells of Escherichia coli ATCC 25922 showed exponential curves when exposed to gamma and electron beam irradiation. Low energy electron beams in air showed little differences from nitrogen stream in their germicidal effectiveness against dry spores of B. pumilus. The D values of B. pumilus spores inoculated on metal plates decreased as the amounts of backscattering electrons from the plates increased. There was adequate correlation between the D value (linear region of survival curve), average D value (6D/6) and 1% survival dose and backscattering factor. Depth dose profile and backscatterig dose of low energy electron beams were measured by radiochromic dye film dosimeter (RCD). These figures were not always in accord with the observed germicidal effectiveness against B. pumilus spores because of varying thickness of RCD and spores inoculated on carrier material. The dry spores were very thin and this thinness was useful in evaluating the behavior of low energy electrons. (author)

The effect of UV-C exposure on larval survival of the dreissenid quagga mussel

Science.gov (United States)

Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri K.; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

2015-01-01

The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

Science.gov (United States)

Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

2015-01-01

The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

UV-C 13-50 ultraviolet irradiation unit for surface sterilization

International Nuclear Information System (INIS)

Bachmann, R.

1979-01-01

Brown Boveri have developed new watertight ultraviolet irradiation units for surface sterilization. Their main application is in packing techniques in the foodstuffs and pharmaceutical industries. This article describes the construction, germicidal effect, and applications of these irradiation units. (Auth.)

Medicine Delivery Device with Integrated Sterilization and Detection

Science.gov (United States)

Shearn, Michael J.; Greer, Harold F.; Manohara, Harish

2013-01-01

Sterile delivery devices can be created by integrating a medicine delivery instrument with surfaces that are coated with germicidal and anti-fouling material. This requires that a large-surface-area template be developed within a constrained volume to ensure good contact between the delivered medicine and the germicidal material. Both of these can be integrated using JPL-developed silicon nanotip or cryo-etch black silicon technologies with atomic layer deposition (ALD) coating of specific germicidal layers. The application of semiconductor processing techniques and technologies to the problems of fluid manipulation and delivery has enabled the integration of chemical, electrical, and mechanical manipulation of samples all within a single microfluidic device. This approach has been successfully applied at JPL to the automated processing, detection, and analysis of minute quantities (parts per trillion level) of biomaterials to develop instruments for in situ exploration or extraterrestrial bodies. The same nanofabrication techniques that are used to produce a microfluidics device are also capable of synthesizing extremely high-surface-area templates in precise locations, and coating those surfaces with conformal films to manipulate their surface properties. This methodology has been successfully applied at JPL to produce patterned and coated silicon nanotips (also known as black silicon) to manipulate the hydrophilicity of surfaces to direct the spreading of fluids in microdevices. JPL's ALD technique is an ideal method to produce the highly conformal coatings required for this type of application. Certain materials, such as TiO2, have germicidal and anti-fouling properties when they are illuminated with UV light. The proposed delivery device contacts medicine with this high-surface-area black silicon surface coated with a thin-film germicidal deposited conformally with ALD. The coating can also be illuminated with ultraviolet light for the purpose of sterilization

21 CFR 880.6890 - General purpose disinfectants.

Science.gov (United States)

2010-04-01

... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use... disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A general... prior to terminal sterilization or high level disinfection. Noncritical medical devices make only...

9 CFR 590.504 - General operating procedures.

Science.gov (United States)

2010-01-01

... EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT) Sanitary... with clean and sanitary methods and shall be conducted as rapidly as practicable. Pasteurization, heat... processed, stored or handled. (h) Only germicides, insecticides, rodenticides, detergents, or wetting agents...

Study on a New Ultraviolet Sterilizer to the Surface Disinfection of the Ultrasound Probe.

Science.gov (United States)

Chen, Gui Qiu; Chen, Yu Hao; Yi, Liang; Yin, Jin; Gao, Qiong; Song, Jiang Nan; Li, Shi Kang; Chen, Pei Hou; Guo, Gui Ping

2018-02-01

We studied the disinfection effect of a new ultraviolet (UV) sterilizer and its utilization on ultrasound probe surfaces. Carrier quantitative germicidal tests, simulated on-the-spot trials, and organic substance influence tests were used to carry out experimental observation. Artificially infected probes were disinfected using the sterilizer or a germicidal lamp for comparison. The total number and types of bacteria were determined and identified. Our results demonstrated the sterilizer had the best disinfection effect among three different disinfection methods in hospital. The sterilizer has been used in a hospital setting for 2 years with no notable damage to the ultrasound probe instrument. It has the advantages of fast disinfection, high disinfection effect, and good compatibility with the ultrasound instrument, worthy of being a promoted application in medical institutions. Copyright © 2018 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Psidium guajava and Piper betle Leaf Extracts Prolong Vase Life of Cut Carnation (Dianthus caryophyllus Flowers

Directory of Open Access Journals (Sweden)

M. M. Rahman

2012-01-01

Full Text Available The effect of leaf extracts of Psidium guajava and Piper betle on prolonging vase life of cut carnation flowers was studied. “Carola” and “Pallas Orange” carnation flowers, at bud stage, were pulsed 24 hours with a floral preservative. Then, flowers were placed in a vase solution containing sprite and a “germicide” (leaf extracts of P. guajava and P. betle, 8-HQC, or a copper coin. Flowers treated with 8-HQC, copper coin, and leaf extracts had longer vase life, larger flower diameter, and higher rate of water uptake compared to control (tap water. The leaf extracts of P. guajava and P. betle showed highest antibacterial and antifungal activities compared to the other treatments. Both showed similar effects on flower quality as the synthetic germicide, 8-HQC. Therefore, these extracts are likely natural germicides to prolong vase life of cut flowers.

The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

Directory of Open Access Journals (Sweden)

Alecia Stewart-Malone

Full Text Available The rapid spread of quagga mussels (Dreissena rostriformis bugensis has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

The Effect of Air Plasma on Sterilization of Escherichia coli in Dielectric Barrier Discharge

International Nuclear Information System (INIS)

Hu Miao; Guo Yun

2012-01-01

In this work, a Dielectric Barrier Discharge (DBD) air plasma was used to sterilize Escherichia coli (E. coli) on the surface of medical Polyethylene Terephthalate (PET) film. The leakage of cellular DNA and protein by optical absorbance measurement at 260 nm and 280 nm, together with transmission electron microscopy (TEM) about cell morphology were performed after sterilization to analyse inactivation mechanisms. The results indicated that the DBD air plasma was very effective in E. coli sterilization. The plasma germicidal efficiency depended on the plasma treatment time, the air-gap distance, and the applied voltage. Within 5 min of plasma treatment, the germicidal efficiency against E. coli could reach 99.99%. An etching action on cell membranes by electrons, ions and radicals is the primary mechanism for DBD air plasma sterilization, which leads to the effusion of cellular contents (DNA and protein) and bacterial death. (plasma technology)

Germicidal effects of free and combined sulphur dioxide

Energy Technology Data Exchange (ETDEWEB)

Ingram, M

1948-01-01

Yeasts have been exposed to SO/sub 2/ in nutrient solutions with two concentrations of dextrose; chosen so as to induce the same rate of growth in the yeast, but to combine with quite different proportions of the SO/sub 2/ added. It was found that the behavior of the yeast was related to the concentration of free (i.e. iodine-titratable) SO/sub 2/, and not to the amounts of SO/sub 2/ combined or added. In another experiment, a correlation was demonstrated between the rate of growth of yeasts in concentrated orange juice and the concentration of free SO/sub 2/, but not with the combined or total SO/sub 2/; in this experiment however, larger quantities of free SO/sub 2/ were involved than in the first. It is concluded that in relation to the preservative action of SO/sub 2/ the quantities added and going into combination are irrelevant, such action being exerted only through the proportion remaining ''free''. It is nevertheless clear that there are present in fruit juices factors which reduce the effectiveness even of the ''free'' SO/sub 2/.

Ozone Antimicrobial Efficacy

Science.gov (United States)

Ozone is a potent germicide that has been used extensively for water purification. In Europe, 90 percent of the municipal water systems are treated with ozone, and in France, ozone has been used to treat drinking water since 1903. However, there is limited information on the bioc...

42 CFR 494.50 - Condition: Reuse of hemodialyzers and bloodlines.

Science.gov (United States)

2010-10-01

... this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of... of the dialyzer. All hemodialyzers must be discarded before a different chemical germicide is used in... (ii) Undertake evaluation of its dialyzer reprocessing and water purification system. When this...

Killing of Escherichia coli using the gas diffusion electrode system.

Science.gov (United States)

Xu, W Y; Li, P; Dong, B

2010-01-01

To be best of our knowledge, this study is one of the first investigations to be performed into the potential benefits of gas diffusion electrode (GDE) system in controlling inactivation of E. coli. This study mainly focused on the dual electrodes disinfection with gas diffusion cathode, using Escherichia coli as the indicator microorganisms. The effects of Pt load W(Pt) and the pore-forming agent content W(NH(4)HCO(3)) in GDE, operating conditions such as pH value, oxygen flow rate Q(O(2)), salt content and current density on the disinfection were investigated, respectively. The experimental results showed that the disinfection improved with increasing Pt load W(Pt), but its efficiency at Pt load of 3 per thousand was equivalent to that at Pt load of 4 per thousand. Addition of the pore-forming agent in the appropriate amount improved the disinfection while drop of pH value resulted in the rapid rise of the germicidal efficacy and the disinfection shortened with increasing oxygen flow rate Q(O(2)). The system is more suitable for highly salt water. The germicidal efficacy increased with current density. However, the accelerating rate was different: it first increased with the current density, then decreased, and reached a maximum at current density of 6.7-8.3 mA/cm(2). The germicidal efficacy in the cathode compartment was about the same as in the anode compartment indicating the contribution of direct oxidation and indirect treatment of E. coli by the hydroxyl radical was similar to the oxidative indirect effect of the generated H(2)O(2). This technology is expensive in operating cost, further research is required to advance the understanding and reduce the operating cost of this technology.

Airfoil-shaped micro-mixers for reducing fouling on membrane surfaces

Science.gov (United States)

Ho, Clifford K; Altman, Susan J; Clem, Paul G; Hibbs, Michael; Cook, Adam W

2012-10-23

An array of airfoil-shaped micro-mixers that enhances fluid mixing within permeable membrane channels, such as used in reverse-osmosis filtration units, while minimizing additional pressure drop. The enhanced mixing reduces fouling of the membrane surfaces. The airfoil-shaped micro-mixer can also be coated with or comprised of biofouling-resistant (biocidal/germicidal) ingredients.

40 CFR 141.720 - Inactivation toolbox components.

Science.gov (United States)

2010-07-01

... paragraph (b) or (c) of this section must calculate CT at least once each day, with both C and T measured... are for UV light at a wavelength of 254 nm as produced by a low pressure mercury vapor lamp. To receive treatment credit for other lamp types, systems must demonstrate an equivalent germicidal dose...

Photoreactivation of UV-irradiated Legionella pneumophila and other Legionella species

International Nuclear Information System (INIS)

Knudson, G.B.

1985-01-01

Shortwave UV light was assessed as a feasible modality for the control of Legionnaires disease bacterium in water. The results of this study show that Legionella pneumophila and six other Legionella species are very sensitive to low doses of UV. However, all Legionella species tested effectively countered the germicidal effect of UV when subsequently exposed to photoreactivating light

Author Details

African Journals Online (AJOL)

Retrospective studies on pullorum disease in chickens in Zaria, Nigeria Abstract PDF · Vol 7, No 2 (2008) - Articles Disinfectant effects of Purit®, Z-Germicide® and Carcil® on bacterial isolates from hatcheries in Kaduna state, Nigeria Abstract PDF · Vol 10, No 2 (2012) - Articles Risk factors for the occurrence and spread of ...

Evaluation of the Performance of Iodine-Treated Biocide Filters Challenged with Bacterial Spores and Viruses

Science.gov (United States)

2006-11-01

the iodine-treated media. D. METHODOLOGY: The iodine-treated filter media were challenged by Bacillus subtilis spores and MS2 bacteriophage...reentrainment into the air [8]. Even though HVAC prevents the contamination of indoor air from environmental bacteria and spores entering from outdoors...of iodine with Bacillus metiens spores showed that the decrease of germicidal activity is due to increased iodine decomposition [39]. Studies on the

Efficacy of Nano Germicidal Light Therapy on Wound Related Infections

Science.gov (United States)

2016-09-12

Taghipour F. Application of ultraviolet light-emitting diodes ( UV - LEDs ) for water disinfection: A review. Water research. 2016;94:341-349. 54. Zakaria F...of ultraviolet light-emitting diodes ( UV - LEDs ) for water disinfection: A review. Water research. 2016;94:341-349. 54. Zakaria F, Harelimana B...224. 42. Wekhof A. Disinfection with flash lamps . PDA J Pharm Sci Technol. 2000;54(3):264- 276. 43. Dai T, Tegos GP, Rolz-Cruz G, Cumbie WE

Efecto de la exposición a la luz ultravioleta uv-c en la viabilidad de especies de Eschericha coli y Salmonella typhimurium

OpenAIRE

Oviedo, Dumas; Rojas, Jesús María; Borda, Ricardo Alberto; Durango, Mónica María

2013-01-01

Introduction. The germicidal effect UV-C light has is regarded as an effective tool to inactivate and eliminate harmful contaminating agents, such as Escherichia coli and Salmonella typhimurium. Objective. evaluating the effectiveness of UV-C light for reducing Escherichia coli and Salmonella typhimorium populations from cultures that had the microorganisms, combining factors like concentration, time and distance. Methodology. A UV-C lamp, with a 254 nm and 8 ...

Microbial Removal Efficiency of UV in Tehran Shahid Mahallati Wastewater Treatment Plant

Directory of Open Access Journals (Sweden)

Reza Dabbagh

2009-03-01

Full Text Available Shahid Mahallati Wastewater Treatment Plant was selected for installing a UV disinfection unit to investigate its germicidal effect on microbial removal. Low pressure mercury lamps were used to generate germicidal ultraviolet radiation (UV-C. The UV system was operated over a period of 6 months that included both warm and cold seasons. A maximum UV disinfection efficiency of 14.4m3/h was recorded for the system on the basis of design criteria within turbidity ranges of 9 to 32 NTU. The minimum UV dose applied in the UV unit was 40000 µW.s/cm2 and the highest bacterial density in the UV unit influent was 5.6*107. Effluent total coliform or fecal coliform enumeration after exposure to UV ray showed the microbial density decreasing from four logs, or 99.99%, to as high as six logs, or 99.9999% removal efficiency, under different conditions. Effluent microbial densities in terms of total and fecal coliforms were below 1000MPN/100mL and 400MPN/100mL, respectively. These values comply with wastewater discharge or agricultural irrigation standards according to Iran Department of Environment. From our results, it is concluded that UV disinfection may be an effective technique for wastewater disinfection in Iranian wastewater treatment plants.

Advanced oxidation technologies H{sub 2}O{sub 2}/UV evaluation in the treatment of effluent containing VCH (Vinylcyclohexene); Avaliacao do processo oxidativo avancado H{sub 2}O{sub 2}/UV no tratamento de efluente contendo VCH (Vinilciclohexeno)

Energy Technology Data Exchange (ETDEWEB)

Lenise, V.F.G.; Dezotti, M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Quimica; Aquino Neto, F.R. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica

2004-07-01

The study of vinylcyclohexene (VCH) degradation by the advanced oxidation technology H{sub 2}O{sub 2} /UV was researched in a pilot plant containing two Germetec, PFR reactors, with 0.7 L of useful volume. VCH is a persistent organic compound generated by thermal dimerization of 1,3-butadiene. One of the reactors had a warming/colding jacket and a low-pressure mercury vapor lamp, germicidal, of 25 W and the another had a medium-pressure mercury vapor lamp of 1.7 KW. Synthetic effluents containing VCH, VCH and ethanol and real hydroxyl terminated polybutadiene (HTPB) effluent were researched under different temperature and pH conditions. The aqueous effluent generated in HTPB plant was composed by 10-100 mg/L of VCH, others organic compounds like ethanol, butadiene and polymer, acidic pH, residual peroxide and a mean content of soluble organic carbon of 25000 mg/L. After 30 minutes of H{sub 2}O{sub 2}/UV treatment with a germicidal lamp , VCH was completely degradated while in the reactor with a medium pressure lamp after 5 minutes the complete VCH degradation happened. The degradation of others organic compounds in the effluent was observed with soluble organic carbon content reduction about 80%. The Kinetics of VCH degradation was monitored by GC/MS. (author)

The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel

OpenAIRE

Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

2015-01-01

The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV...

Assessing the in vivo impact of a gel sanitizer on the epidermal "barrier" dynamics

OpenAIRE

Henrique Silva; Sara Aguiar Silva; Hugo Ferreira; L. Monteiro Rodrigues

2015-01-01

Disease prevention and control depend on hand washing, in particular during epidemic surges (e.g. flu). The use of alcohol-based hand sanitizers is strongly recommended due to its high germicide effectiveness. However, its impact on skin physiology, especially on the barrier function, has not been determined, although most of the formulations include different humectants. This study evaluates the impact of a commercially available formulation on in vivo epidermal barrier dynamics. 13 young ad...

The effect of intense light pulses on the sensory quality and instrumental color of meat from different animal breeds

OpenAIRE

Tomašević I.

2015-01-01

Intense light pulses (ILP) are an emerging processing technology, which has a potential to decontaminate food products. The light generated by ILP lamps consists of a continuum broadband spectrum from deep UV to the infrared, especially rich in UV range below 400 nm, which is germicidal. Evaluation of the effect of intense light pulses (ILP) on sensory quality of meat, game and poultry was performed using two kinds of red meat (beef and pork), two kinds of ...

Induction of cellular transformation by irradiation from artificial light sources

International Nuclear Information System (INIS)

Withrow, T.J.

1981-01-01

Cellular transformation in vitro has been used to test for the carcinogenic potential of chemical and physical insults including light. This report discusses the measurement of transformation, and reviews studies done on the effects of exposure to artificial light on cellular transformation or on cellular transformation by a virus. To date, cool-white lamps have been found to cause cellular transformation, while germicidal lamps and sunlamps have been found to cause cellular transformation and to enhance virally produced transformation

Pastures anti-A therapy. Product (1ra part) advance

OpenAIRE

Gálvez Calla, Luis H.; Roque Alcarraz, Mirtha; Villavicencio Gastelú, Jorge

2014-01-01

«in vitro & in vivo» studies of fue Anti-A Experimental Paste, with the help of Sangre de grado and tricalcic phosphate, they have shown an excellent capacity germicide and reparative of the conjunctive tissue. The fibroblástic activity observed in most of the cases, probably generated by effects of the tricálcic phosphate, is the same one that showed a similar behavior in a previous investigation, inducing the reparative process of the bony defects. However, the application of the Anti-A Exp...

Far-UVC light applications: sterilization of MRSA on a surface and inactivation of aerosolized influenza virus

Science.gov (United States)

Welch, David; Buonanno, Manuela; Shuryak, Igor; Randers-Pehrson, Gerhard; Spotnitz, Henry M.; Brenner, David J.

2018-02-01

Methicillin-resistant Staphylococcus aureus (MRSA) and influenza A virus are two of the major targets for new antimicrobial technologies. In contrast to conventional germicidal lamps emitting primarily at 254 nm, which are both carcinogenic and cataractogenic, recent work has shown the potential of far-UVC technology, mainly between 207 and 222 nm, to be an effective means of sterilization of pathogens without apparent harm to mammalian cells. This is because, due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer (non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or smaller dimensions, far-UVC can penetrate and inactivate them. With this report, we present progress on in vitro tests to inactivate MRSA on a surface using far-UVC light from a laser delivered using an optical diffuser. Qualitative and quantitative results show that this means of far-UVC exposure is adequate to inactivate MRSA with a dose comparable to that which would be required using a conventional germicidal lamp. Also included is a report on progress on inactivation of aerosolized influenza A virus. A custom benchtop aerosol exposure chamber was constructed and used to determine the effectiveness of far- UVC. Results indicate that far-UVC efficiently inactivates airborne aerosolized viruses, with a very low dose of 2 mJ/cm2 of 222-nm light inactivating >95% of aerosolized H1N1 influenza virus. Together these studies help to further establish far-UVC technology as a promising, safe and inexpensive tool for sterilization in many environments.

Fungi detoxification study from pistachio by non-ionizing irradiation; Barrasi-ye estefadeh az parto'ha-ye gheyr-e yonsaz dar gharchzoda-i-ye pesteh

Energy Technology Data Exchange (ETDEWEB)

Ghafourian, H; Sadighzadeh, A; Dabbagh, R

1998-07-01

4,6 and 10 minutes of microwaves exposure provides and effective and relatively rapid sterilization for different purposes in medicine and food industries for example sterilization of materials which have been contaminated with Aspergillus flavus (Pcc-5004) and Aspergillus parasiticus (Pcc-5018) which are producer of Aflatoxin especially on pistachios and other dried fruits. Microwaves exposure induces a morphological modification of the cells and germicidal effects of ultrasonic waves has been attributed to gaseous cavitation. There was a significant reduction in fungal growth compared with those under the control which decreased growth with increased microwave and ultrasound exposure time.

Inactivation of certain insect pathogens by ultraviolet radiation

Energy Technology Data Exchange (ETDEWEB)

Krieg, A.; Groener, A.; Huber, J.; Zimmermann, G.

1981-01-01

The UV-sensitivity of two baculoviruses (granulosis virus, nuclear polyhedrosis virus) and two entomopathogenic microorganisms (Bacillus thuringiensis, Beauveria bassiana) was determined by radiation tests. In the far UV (254 nm) the stability, measured at an inactivation rate of 99%, was in declining order: nuclear polyhedra >= conidia of B. bassiana > granula > spores of B. thuringiensis >= vegetative cells of B. thuringiensis. In the near UV (285-380 nm) the following order could be found: conidia of B. bassiana >= nuclear polyhedra > spores of B. thuringiensis >= granula > vegetative cells of B. thuringiensis. Far UV had a much higher germicidal effect for all pathogens tested than near UV.

Fungi detoxification study from pistachio by non-ionizing irradiation

International Nuclear Information System (INIS)

Ghafourian, H.; Sadighzadeh, A; Dabbagh, R.

1998-01-01

4,6 and 10 minutes of microwaves exposure provides and effective and relatively rapid sterilization for different purposes in medicine and food industries for example sterilization of materials which have been contaminated with Aspergillus flavus (Pcc-5004) and Aspergillus parasiticus (Pcc-5018) which are producer of Aflatoxin especially on pistachios and other dried fruits. Microwaves exposure induces a morphological modification of the cells and germicidal effects of ultrasonic waves has been attributed to gaseous cavitation. There was a significant reduction in fungal growth compared with those under the control which decreased growth with increased microwave and ultrasound exposure time

USING A GERMICIDAL INSTALLATION TO IMPROVE THE ENVIRONMENTAL SITUATION AT A POULTRY FARM

Directory of Open Access Journals (Sweden)

T. L. Mayorova

2016-01-01

Full Text Available Aim. The aim is to study the effect of bactericidal installation in combination with a device for creating a water curtain on the microclimate in the poultry house and environment. Methods. Epizootic research was carried out according to "epizootic methodology", FGI «Federal Centre for Animal Health» (FGI «ARRIAH». Gas composition of air was investigated by means of universal gas-analyzer (UG-2; the content of carbon dioxide was measured by Subbotin-Nagorskiy titrimetric method; the amount of dust in the air was measured by a gravimetric (weight method. Air humidity was calculated by means of August statistical psychrometer. Evaluation of the microbial contamination of air was carried out using the Krotov’s device. Results. The performed studies before and after the air bactericidal purification in a poultry farm showed a reduction of carbon dioxide and ammonia by 2-2.5 times, the total microbial contamination of air by 1.9 times and the dust by 4.3 times. We found a direct link between the increases in the amount of microbial bodies of air depending on the age of the bird. Thus, after air-cleaning in the poultry house room where they kept 15-d-old chicks, we calculated 5 thousand microbial cells per one m3 found (E.coli, and at the age of 45 days, the level of contamination reached 11 thousand microbial bodies. Conclusion. Research in the poultry house reveals that using bactericidal installation paired with water curtain device can significantly reduce the concentration of gases, dust and microorganisms in the air of the house and decrease the release into the environment, which will undoubtedly have an impact on the ecological situation of the environment, animal and human health. 

The germicidal effect of the open air in different parts of The Netherlands

NARCIS (Netherlands)

Mik, G. de; Groot, I. de

1977-01-01

Using the microthread technique the survival of Escherichia coli MRE 162 in open air was measured in different parts of The Netherlands. The presence of bactericidal compounds (open air factor=OAF) could be demonstrated on several days and quantitated in relative units of OAF concentration. In the

Antimicrobial efficacy and longevity of silver+zeolite incorporating preinsulated ducts installed in real healthcare settings.

Science.gov (United States)

Tinteri, C; Potenza, M; Rizzetto, R

2012-12-01

The values of microbial growth in the air exiting from the heating, ventilation and air conditioning (HVAC) ducts treated with silver/zeolite have been shown to be lower than those in the air coming out the traditional metal ones. This study aims to verify how long this antimicrobial activity lasts. All the tests were performed according to US ASTM E2180-01 and ISO-JIZ 22196 standards. Samples of aluminum cladding panels of different thickness and incorporating silver-zeolite were tested in order to verify their thickness depending antibacterial activity. The same kind of linings samples were analyzed after a simulated and accelerated ageing process. Ag-zeolite incorporating HVAC duct panels linings were tested after years from their installation, in order to verify the maintenance of their bactericidal power during time. For laminates containing different amounts of silver+Zeolite it was shown that also in panels with minimum thickness tested, the lowest germicidal effect (GE) found was still very good (GE of 5,76 ULog10). After their wearing and tearing the antimicrobial activity tended to increase passing from 7.2081 to 8.29922 LogUnits in panels 80 microns thick. For still hospital working aluminium foils incorporating Silver/Zeolite on panels installed through 2006 and 2008, the antimicrobial action of zeolite was still firmly present even after two years and three years.The germicidal effect standards were maintained even during time on constant values between 7.477 and 7.086 LogUnits. The persistence of bactericidal efficacy of Ag+zeolite treatment in all the materials used for the construction of HVAC ductworks can be confirmed.

Environmental and biological applications of microplasmas

International Nuclear Information System (INIS)

Becker, K; Koutsospyros, A; Yin, S-M; Christodoulatos, C; Abramzon, N; Joaquin, J C; Brelles-Marino, G

2005-01-01

Stable glow-type discharge plasmas at elevated pressures can be generated and maintained easily when the plasma is spatially confined to cavities with critical dimensions below 1 mm ('microplasmas'). We studied the properties of several atmospheric-pressure microplasmas and their use in the remediation of volatile organic compounds (VOCs) and biological decontamination. The VOCs studied include individual prototypcal aliphatic and aromatic compounds as well as mixtures such as BTEX (benzene, toluene, ethylbenzene and xylene). The biological systems under study included individual bacteria as well as bacterial biofilms, which are highly structured communities of bacteria that are very resistant to antibiotics, germicides, and other conventional forms of destruction

Inactivation of certain insect pathogens by ultraviolet radiation

International Nuclear Information System (INIS)

Krieg, A.; Groener, A.; Huber, J.; Zimmermann, G.

1981-01-01

The UV-sensitivity of two baculoviruses (granulosis virus, nuclear polyhedrosis virus) and two entomopathogenic microorganisms (Bacillus thuringiensis, Beauveria bassiana) was determined by radiation tests. In the far UV (254 nm) the stability, measured at an inactivation rate of 99%, was in declining order: nuclear polyhedra >= conidia of B. bassiana > granula > spores of B. thuringiensis >= vegetative cells of B. thuringiensis. In the near UV (285-380 nm) the following order could be found: conidia of B. bassiana >= nuclear polyhedra > spores of B. thuringiensis >= granula > vegetative cells of B. thuringiensis. Far UV had a much higher germicidal effect for all pathogens tested than near UV. (orig.) [de

Contact lens disinfection by ultraviolet light

International Nuclear Information System (INIS)

Dolman, P.J.; Dobrogowski, M.J.

1989-01-01

A 253.7-nm ultraviolet light with an intensity of 1,100 microW/cm2 was tested for its germicidal activity against contact lenses and storage solutions contaminated with various corneal pathogens. The exposure time necessary to reduce a concentration of organisms from 10(6)/ml to less than 10/ml was 30 seconds for Staphylococcus aureus, 60 seconds for Pseudomonas aeruginosa, and 84 seconds for Candida albicans. The time necessary to sterilize a suspension of 10(4)/ml Acanthamoeba polyphaga was less than three minutes with this technique. Four brands of soft contact lenses were exposed to ultraviolet light for over eight hours without changing their appearance, comfort, or refraction

Quitina y quitosano: materiales del pasado para el presente y el futuro

Directory of Open Access Journals (Sweden)

Cristóbal Lárez Velásquez

2006-09-01

Full Text Available The present work shows, in a clear and simple way, industrial production and common applications oftwo ancient natural polymers on earth but very current due to its application possibilities: chitin andchitosan. Here a simple sample of the wide possible range are described, being shown these due to therelevance that these may have in the development of vital areas in the country like: agriculture (seedsprotection, fertilizers and fungicides controlled release, etc., waste water treatment (flocculants,coagulant, demetalization agents, dyes removing agents, pesticides, etc. medicine (glucosamineproduction, healing creams, genetic therapy, etc., cosmetics (slimming, moisturizing agent,preservative germicide in soaps, shampoos, etc. and biosensors (detection of pathogenic agents infoods, toxic species in residual waters, etc..

Pollen DNA repair after treatment with the mutagens 4-nitroquinoline-1-oxide, ultraviolet and near-ultraviolet irradiation, and boron dependence of repair

International Nuclear Information System (INIS)

Jackson, J.F.; Linskens, H.F.; Katholieke Universiteit Nijmegen

1979-01-01

Irradiation of dry, mature pollen from Petuna hybrida with near-ultraviolet light from an erythemal-sunlamp gave rise to a repair-like, unscheduled DNA synthesis during the early stages of in vitro germination. Like that brought about by far-ultraviolet light from a germicidal lamp, this DNA synthesis is enhanced by hydroxyurea added to the germination medium, and reduced by photoreactivating light given after ultraviolet irradiation and before germination begins. It is concluded that pollen, often receiving considerable exposure to sunlight, has, in addition to the protection afforded by the ultraviolet filtering effects of yellow pigments, also the capacity to repair ultraviolet produced changes in DNA, by both photoreactivation and dark repair processes. (orig./AJ) [de

Evaluation of RO modules for the SSP ETC/LSS.

Science.gov (United States)

Jasionowski, W. J.; Bambenek, R. A.

1973-01-01

During the past eight years the NASA Manned Spacecraft Center has supported the development of an Integrated Water and Waste Management System for use in the Space Station Prototype (SSP) Environmental Thermal Control/Life-Support System (ETC/LSS). This system includes the reverse osmosis (RO) process for recycling wash water and the compression distillation process for recovering useable water from urine, urinal flush water, humidity condensate, commode flush water and the wash water concentrated by RO. This paper summarizes the experimental work performed during the past four years to select the best commercially available RO module for this system and to also define which surfactants and germicides are most compatible with the selected module.

Ultraviolet-x-ray interaction: mutation and transformation

International Nuclear Information System (INIS)

Han, A.; Elkind, M.M.; Suzuki, F.; Dainko, J.L.; Buess, E.

1981-01-01

The overall long-range objectives of the proposed research are to: (1) determine whether ionizing and nonionizing radiations interact in the induction of mutation and neoplastic transformation; (2) identify the nature of the interaction; (3) establish the possible relationship between the repair processes and the expression of interactive damage related to mutation and neoplastic transformation. Principal methods were used to assess survival, mutation, and neoplastic transformation of mammalian cells in culture. Cells were exposed to the following radiations: 50-kV x-rays; light from a germicidal lamp, uv-C (254 nm); light from unfiltered sun lamps, uv-B (290 to 345 nm); and light from sun lamps filtered by polystyrene dish covers

Ultraviolet germicidal efficacy as a function of pulsed radiation parameters studied by spore film dosimetry.

Science.gov (United States)

Bauer, Stefan; Holtschmidt, Hans; Ott, Günter

2018-01-01

Disinfection by pulsed ultraviolet (UV) radiation is a commonly used method, e.g. in industry or medicine and can be carried out either with lasers or broadband UV radiation sources. Detrimental effects to biological materials depending on parameters such as pulse duration τ or pulse repetition frequency f p are well-understood for pulsed coherent UV radiation, however, relatively little is known for its incoherent variant. Therefore, within this work, it is the first time that disinfection rates of pulsed and continuous (cw) incoherent UV radiation studied by means of spore film dosimetry are presented, compared with each other, and in a second step further investigated regarding two pulse parameters. After analyzing the dynamic range of the Bacillus subtilis spore films with variable cw radiant exposures H=5-100Jm -2 a validation of the Bunsen-Roscoe law revealed its restricted applicability and a 28% enhanced detrimental effect of pulsed compared to cw incoherent UV radiation. A radiant exposure H=50Jm -2 and an irradiance E=0.5Wm -2 were found to be suitable parameters for an analysis of the disinfection rate as a function of τ=0.5-10ms and f p =25-500Hz unveiling that shorter pulses and lower frequencies inactivate more spores. Finally, the number of applied pulses as well as the experiment time were considered with regard to spore film disinfection. Copyright © 2017 Elsevier B.V. All rights reserved.

Patient and environmental service employee satisfaction of using germicidal bleach wipes for patient room cleaning.

Science.gov (United States)

Aronhalt, Kimberly C; McManus, James; Orenstein, Robert; Faller, Rebecca; Link, Mary

2013-01-01

More healthcare institutions are using bleach products which are sporicidal to reduce Clostridium difficile infection (CDI). There may be patient and employee concerns about the appearance of bleach residue left on surfaces, odors, and respiratory tract irritation. The intervention used bleach wipes for daily and terminal patient room cleaning to reduce transmission of CDI and was implemented on patient care units with a relatively high incidence of CDI. Both patients and Environmental Services (ES) staff were surveyed to assess their satisfaction of the bleach wipe product used during room cleaning. Patients (n = 94) (91%) continued to be very satisfied with how well their rooms were cleaned every day. Bleach wipes were well tolerated by patients (n = 44) (100%) surveyed on the medical units and less tolerated by patients (n = 50) (22%) on the hematology-oncology units. ES staff (6) reported less satisfaction and more respiratory irritation from using the bleach wipes; however, later their satisfaction improved. © 2012 National Association for Healthcare Quality.

Complete genome sequence of Bacillus subtilis BSD-2, a microbial germicide isolated from cultivated cotton.

Science.gov (United States)

Liu, Hongwei; Yin, Shuli; An, Likang; Zhang, Genwei; Cheng, Huicai; Xi, Yanhua; Cui, Guanhui; Zhang, Feiyan; Zhang, Liping

2016-07-20

Bacillus subtilis BSD-2, isolated from cotton (Gossypium spp.), had strong antagonistic activity to Verticillium dahlia Kleb and Botrytis cinerea. We sequenced and annotated the BSD-2 complete genome to help us the better use of this strain, which has surfactin, bacilysin, bacillibactin, subtilosin A, Tas A and a potential class IV lanthipeptide biosynthetic pathways. Copyright © 2016 Elsevier B.V. All rights reserved.

Tuberculosis Infection Control in Health-Care Facilities: Environmental Control and Personal Protection.

Science.gov (United States)

Lee, Ji Yeon

2016-10-01

Transmission of tuberculosis (TB) is a recognized risk to patients and healthcare workers in healthcare settings. The literature review suggests that implementation of combination control measures reduces the risk of TB transmission. Guidelines suggest a three-level hierarchy of controls including administrative, environmental, and respiratory protection. Among environmental controls, installation of ventilation systems is a priority because ventilation reduces the number of infectious particles in the air. Natural ventilation is cost-effective but depends on climatic conditions. Supplemented intervention such as air-cleaning methods including high efficiency particulate air filtration and ultraviolet germicidal irradiation should be considered in areas where adequate ventilation is difficult to achieve. Personal protective equipment including particulate respirators provides additional benefit when administrative and environmental controls cannot assure protection.

The Determination of Bromine in Wheat, Flour and Bread by Neutron Activation Analysis. RCN Report

International Nuclear Information System (INIS)

Das, H.A.; Hoede, D.; Zonderhuis, J.

1969-07-01

Gaseous germicides are commonly used to improve the tenability of wheat. The bulk material is exposed to a gas which is highly poisonous to fungi. Methylene and ethylene dibromide are often used for this purpose. Traces of these compounds in wheat, flour and bread are dangerous. Consequently, the persistence of these gases should be determined experimentally. This implies that sensitive methods to detect traces of methylene and ethylene dibromide must be available. Neutron activation analysis can be used to determine the total amount of bromine present in the sample. This datum is a useful addition to the gaschromato-graphic determinations of the compounds involved. A routine method for the determination of bromine in corn, flour and bread has been developed and is described in the text

Upgrading and extended testing of the MSC integrated water and waste management hardware

Science.gov (United States)

Bambenek, R. A.; Nuccio, P. P.; Hurley, T. L.; Jasionowski, W. J.

1972-01-01

The results are presented of upgrading and testing an integrated water and waste management system, which uses the compression distillation, reverse osmosis, adsorption filtration and ion-exchange processes to recover potable water from urine, flush water and used wash water. Also included is the development of techniques for extending the useful biological life of biological filters, activated carbon filters and ion-exchange resins to at least 30 days, and presterilizing ion-exchange resins so that sterile water can be recovered from waste water. A wide variety of reverse osmosos materials, surfactants and germicides were experimentally evaluated to determine the best combination for a wash water subsystem. Full-scale module tests with real wash water demonstrated that surface fouling is a major problem.

Methods for air cleaning and protection of building occupants from airborne pathogens

DEFF Research Database (Denmark)

Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor

2009-01-01

germicidal irradiation (UVGI), photocatalytic oxidation (PCO), plasmacluster ions and other technologies for air disinfection and purification from pathogens are analyzed with respect to currently used air distribution principles. The importance of indoor air characteristics, such as temperature, relative...... of transmission, i.e. the generation of pathogen laden droplets originating in the respiratory tract of an infected individual, the survivability of the pathogens, their dispersal indoors and their transfer to a healthy person are reviewed. The advantages and the drawbacks of air dilution, filtration, ultraviolet...... humidity and velocity for the efficiency of each method is analyzed, taking into consideration the nature of the pathogens themselves. The applicability of the methods to the different types of total volume air distribution used at present indoors, i.e. mixing, displacement and underfloor ventilation...

Causes of cell death following ultraviolet B and C exposures and the role of carotenes

Energy Technology Data Exchange (ETDEWEB)

Cerda-Olmedo, Enrique; Martin-Rojas, Virginia; Cubero, Beatriz [Seville Univ. (Spain). Dept. de Genetica

1996-09-01

Ultraviolet B radiation (wavelength 290-310 nm) does not induce any specific lethal effects in the fungus Phycomyces blakesleeanus, according to a heterokaryon test that responds to the nature of the lethal damage. This agent is about 10 times less lethal than UVC radiation from germicidal lamps (254 nm), but it kills cells through the same photoreactivable lesions, due to the UV absorption of DNA. Carotenes do not protect Phycomyces against UV damage, either B or C, lethal or not. This was shown by Darwinian competition experiments between strains containing very different carotene concentrations and between strains containing similar concentrations of different carotenes (phytoene, lycopene, {beta}-carotene). A shading effect of carotenes against UV radiation is likely, but it was insignificant under the conditions of the experiments. (Author).

Causes of cell death following ultraviolet B and C exposures and the role of carotenes

International Nuclear Information System (INIS)

Cerda-Olmedo, Enrique; Martin-Rojas, Virginia; Cubero, Beatriz

1996-01-01

Ultraviolet B radiation (wavelength 290-310 nm) does not induce any specific lethal effects in the fungus Phycomyces blakesleeanus, according to a heterokaryon test that responds to the nature of the lethal damage. This agent is about 10 times less lethal than UVC radiation from germicidal lamps (254 nm), but it kills cells through the same photoreactivable lesions, due to the UV absorption of DNA. Carotenes do not protect Phycomyces against UV damage, either B or C, lethal or not. This was shown by Darwinian competition experiments between strains containing very different carotene concentrations and between strains containing similar concentrations of different carotenes (phytoene, lycopene, β-carotene). A shading effect of carotenes against UV radiation is likely, but it was insignificant under the conditions of the experiments. (Author)

Degradação do pesticida Padron® por processos fotoquímicos utilizando luz artificial e solar Degradation of Padron® by photochemical processes using artificial and sunlight radiation

Directory of Open Access Journals (Sweden)

Silvio César Godinho Teixeira

2007-01-01

Full Text Available Destruction of Padron® (dye and picloram was evaluated using a photoreactor and a solar reactor. Photolysis was observed using only a germicide lamp (GL. Black light (BL and H2O2 (172 mmol L-1 promoted a conversion of 49% and 6% of dye and picloram, respectively. Photocatalytic processes were more efficient using TiO2/GL (96%-dye; 60%-picloram than TiO2/BL (44%-dye; 40%-picloram. Photolysis using sunlight was not observed during PadronÒ recirculation in the reactor constructed with four borosilicate tubes. Meanwhile, adding H2O2 resulted in 12% conversion of dissolved organic compounds. Finally, the most efficient mineralization (60% was obtained using the Fenton reaction ( H2O2-176 mmol L-1; FeSO4x6H2O-90 mmol L-1 and sunlight.

Al x Ga1‑ x N-based semipolar deep ultraviolet light-emitting diodes

Science.gov (United States)

Akaike, Ryota; Ichikawa, Shuhei; Funato, Mitsuru; Kawakami, Yoichi

2018-06-01

Deep ultraviolet (UV) emission from Al x Ga1‑ x N-based light-emitting diodes (LEDs) fabricated on semipolar (1\\bar{1}02) (r-plane) AlN substrates is presented. The growth conditions are optimized. A high NH3 flow rate during metalorganic vapor phase epitaxy yields atomically flat Al y Ga1‑ y N (y > x) on which Al x Ga1‑ x N/Al y Ga1‑ y N multiple quantum wells with abrupt interfaces and good periodicity are fabricated. The fabricated r-Al x Ga1‑ x N-based LED emits at 270 nm, which is in the germicidal wavelength range. Additionally, the emission line width is narrow, and the peak wavelength is stable against the injection current, so the semipolar LED shows promise as a UV emitter.

UV inactivation of pathogenic and indicator microorganisms

International Nuclear Information System (INIS)

Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

1985-01-01

Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts

UV inactivation of pathogenic and indicator microorganisms

Energy Technology Data Exchange (ETDEWEB)

Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

1985-06-01

Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.

Potential use of ozone in the food processingPotencialidades do uso do ozônio no processamento de alimentos

Directory of Open Access Journals (Sweden)

Mariana Curtinovi Geyer

2011-07-01

Full Text Available Ozone is a colorless and unstable gas with pungent smell and partially soluble in water, which is characterized by its high oxidant power. It is a strong agent disinfectant with high power germicidal properties acting in the inactivation of a wide variety of pathogenic organisms, including bacteria, virus and protozoa, presenting a germicidal efficiency that exceeds chlorine. Ozonization has become well-known in recent decades due to implementation of standards increasingly restrictive concerning the by-products of chlorination. Unlike chlorine, ozone do not form halogenated compounds with organic matter. However, it may form several other organic and inorganic. In the food industry, ozone can be use in sanitization processes of equipments and surfaces, as well as in the direct use on foodstuff in order to inactivate microorganisms and to extend shelf-life of food products.O ozônio é um gás incolor de odor pungente, instável e parcialmente solúvel em água, que se destaca por seu elevado poder oxidante. É um forte agente desinfetante com ação sobre uma grande variedade de organismos patogênicos, incluindo bactérias, vírus e protozoários, apresentado uma eficiência germicida que excede ao cloro. O uso do ozônio tornou-se notório nas últimas décadas em função da implementação de padrões cada vez mais restritos em relação aos subprodutos da cloração. Ao contrário do cloro, o ozônio não forma subprodutos halogenados com a matéria orgânica, mas pode induzir a formação de outros subprodutos orgânicos e inorgânicos. Na indústria de alimentos, o ozônio pode ser utilizado em processos de sanitização de superfícies e equipamentos, bem como no uso direto sobre as matérias-primas com o objetivo de inativar microrganismos e aumentar a vida-de-prateleira dos produtos alimentícios.

Reassessment of the differential effects of ultraviolet and ionizing radiation on HIV promoter: the use of cell survival as the basis for comparisons

International Nuclear Information System (INIS)

Beer, J.Z.; Olvey, K.M.; Lee, W.; Zmudzka, B.Z.

1994-01-01

Effects of different radiation treatments on the human immunodeficiency virus-1 (HIV) promoter were reassessed for exposures comparable to those encountered in clinical or cosmetic practice, using survival of the host cell as a basis for comparisons. The exposures were performed with two ultraviolet radiation sources commonly used as medical or cosmetic devices (UVASUN 2000 and FS20 lamps), a germicidal (G15T8) lamp and an X-ray machine. The UVC component of the FS20 lamp was filtered out. The emission spectra of the lamps were determined. The characteristics of these sources allowed us to discriminate among effects of UVA1 (340-400 nm), UVB + UVA2 (280-340 nm) and UVC (254 nm) radiations. Effects of irradiation were ascertained using cultures of HeLa cells stably transfected with the HIV promoter linked to a reporter-chloramphenicol acetyl transferase-gene. (Author)

Inhibition of in vitro SV40 DNA replication by ultraviolet light

International Nuclear Information System (INIS)

Gough, G.; Wood, R.W.

1989-01-01

Ultraviolet light-induced DNA damage was found to inhibit SV40 origin-dependent DNA synthesis carried out by soluble humancell extracts. Replication of SV40-based plasmids was reduced to approx. 35% of that in unirradiated controls after irradiation with 50-100 J/m 2 germicidal ultraviolet light, where an average of 3-6 pyrimidine dimer photoproducts were formed per plasmid circle. Inhibition of the DNA helicase activity of T antigen (required for initiation of replication in the in vitro system) was also investigated, and was only significant after much higher fluences, 1000-5000 J/m 2 . The data indicate that DNA damage by ultraviolet light inhibits DNA synthesis in cell-free extracts principally by affecting components of the replication complex other than the DNA helicase activity of T antigen. The soluble system could be used to biochemically investigate the possible bypass or tolerance of DNA damage during replication (author). 21 refs.; 2 figs

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Chatterjee, A; Bhattacharya, A K

1988-06-01

The incorporation of (/sup 14/C)adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with /sup 60/Co ..gamma..-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of ..gamma..-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after high doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m/sup -2/) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as ..gamma..-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli

International Nuclear Information System (INIS)

Chatterjee, A.; Bhattacharya, A.K.

1988-01-01

The incorporation of [ 14 C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60 Co γ-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of γ-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after high doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m -2 ) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as γ-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells. (author)

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli.

Science.gov (United States)

Chatterjee, A; Bhattacharya, A K

1988-06-01

The incorporation of [14C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60Co gamma-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of gamma-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after higher doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m-2) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as gamma-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.

Loss of photoreversibility for UV mutation in E. coli using 405 nm or near-UV challenge

International Nuclear Information System (INIS)

Kristoff, S.; Bockrath, R.

1983-01-01

E. coli mutagenized with germicidal ultraviolet light (UV) were incubated to allow for development of mutation-fixation processes. Fixation was estimated from the effects on mutation frequency of photoreactivation challenge during the first 60 min post-UV. Two different light sources were used for photoreactivation, one providing effective light primarily at 405 nm and another providing a broad range of near-UV around 365 nm. Kinetics for the loss of photoreversibility (LOP) were determined. The times for completion of LOP in wild-type cells indicated one fixation process for back mutation and another for de novo or converted suppressor mutation regardless of the light source. Using 405-nm light for photoreactivation, the LOP kinetics for back mutation and de novo suppressor mutation in uvrA cells were similar. Hence, classical observations were confirmed here. Immediately post-UV all mutation frequencies were more sensitive to near-UV than 405-nm light. (orig./AJ)

Defining the Effectiveness of UV Lamps Installed in Circulating Air Ductwork

Energy Technology Data Exchange (ETDEWEB)

Douglas VanOsdell; Karin Foarde

2002-11-30

Germicidal ultraviolet (UVGI) lamps have a long history of use for inactivating microbial aerosols. Most reports have focused on the control of infectious diseases, such as tuberculosis (TB), in the occupied spaces of medical facilities. Ventilation duct use of UVGI has been increasing. In-duct applications are generally more concerned with controlling environmental organisms than with controlling infections agents. This document reports the results of a project to investigate the ability of UVGI lamps to inactivate representative environmental microbial aerosols in ventilation ducts. During this research, UVGI lamps were experimentally demonstrated to inactivate bioaerosols composed of vegetative bacteria, bacteria spores, or fungal spores to a reproducible degree under conditions of fixed dose. Vegetative bacteria were most susceptible to UVGI, with bacteria and fungal spores being substantially more resistant. The performance equation commonly cited in the literature for UVGI inactivation was found to generally apply, provided its parameters were known. Revision of final report DOE/OR22674/610-40030-01. Revised table 5 on page 33.

New Copolymers Containing Charge Carriers for Organic Devices with ITO Films Treated by UV-Ozone Using High Intensity Discharge Lamp

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Emerson Roberto SANTOS

2009-02-01

Full Text Available For electroluminescent devices new copolymers were synthesized using a Suzuki cross-coupling reaction based on monomers (fluorine-alt-phenylene in conjugation with quinoline-alt-phenylene units. They were characterized by 1H NMR, 13C NMR and FTIR. TGA measurements indicated that the copolymers have good thermal properties and no weight loss was observed up to 250 °C. The UV-Vis spectra were characterized by absorptions from the fluorene-alt-phenylene and quinoline-alt-phenylene segments in the backbone, while their photoluminescence (PL spectra dominated by emissions from the fluorene excimer. For devices assembly ITO films were treated using a High Intensity Discharge Lamp (HPMVL without outer bulb presenting high ozone concentration than that conventional germicidal lamp. The device with ITO treated revealed significant decrease of threshold voltage (or turn-on voltage compared by untreated with I-V curves. This decrease can be related by water and carbon dioxide extracted on surface after UV-Ozone treatment revealed by DRIFT measurements.

INFLUENCE OF ULTRAVIOLET RADIATION ON MICROBIOLOGICAL AND SENSORY CHARACTERISTICS OF CERTAIN CATEGORIES OF VEGETABLES PRODUCTS AND THEIR PRESERVATION LIFE

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Danilevici Constantin

2010-01-01

Full Text Available Research paper aims to highlight the scientific correlation between the influence of ultraviolet radiation (UV onsensory and microbiological characteristics of plant products in the category of leaves (lettuce and other types ofvegetables or fruit (bananas and their preservation’s duration, through their UV irradiation under certain conditions.The literature indicates a germicidal action of UV (medium UV on micro-organisms, optimal for λ = 254 nm. Theeffectiveness of radiation is influenced by duration of irradiation, the distance between the radiation source and thesample product and radiant power source.The action of microbial cell inactivation or destruction can be explained by changes in cellular structure andpermeability with changes at the level of mitochondria and the genetic material as a result of photochemical effects ofUV products. Research highlights the preservative effect of UV radiation (with λ = 254 nm and also their influence onsensory properties and positive to negative for leafy vegetables and fruits (bananas in our case.

The effect of UV light on the inactivation of Giardia lamblia and Giardia muris cysts as determined by animal infectivity assay (P-2951-01).

Science.gov (United States)

Mofidi, Alexander A; Meyer, Ernest A; Wallis, Peter M; Chou, Connie I; Meyer, Barbara P; Ramalingam, Shivaji; Coffey, Bradley M

2002-04-01

This study measured the effect of germicidal ultraviolet (UV) light on Giardia lamblia and Giardia muris cysts, as determined by their infectivity in Mongolian gerbils and CD-1 mice, respectively. Reduction of cyst infectivity due to UV exposure was quantified by applying most probable number techniques. Controlled bench-scale, collimated-beam tests exposed cysts suspended in filtered natural water to light from a low-pressure UV lamp. Both G. lamblia and G. muris cysts showed similar sensitivity to UV light. At 3 mJ/cm2, a dose 10-fold lower than what large-scale UV reactors may be designed to provide, > 2-log10 (99 percent) inactivation was observed. These results, combined with previously published data showing other protozoa and bacteria have similar, high sensitivity to UV light, establish that UV disinfection of drinking water is controlled by viruses which may require over 10-fold more UV dose for the same level of control.

Resistance of Pseudomonas aeruginosa to liquid disinfectants on contaminated surfaces before formation of biofilms.

Science.gov (United States)

Sagripanti, J L; Bonifacino, A

2000-01-01

A comparison was made of the effectiveness of popular disinfectants (Cavicide, Cidexplus, Clorox, Exspor, Lysol, Renalin, and Wavicide) under conditions prescribed for disinfection in the respective product labels on Pseudomonas aeruginosa either in suspension or deposited onto surfaces of metallic or polymeric plastic devices. The testing also included 7 nonformulated germicidal agents (glutaraldehyde, formaldehyde, peracetic acid, hydrogen peroxide, sodium hypochlorite, phenol, and cupric ascorbate) commonly used in disinfection and decontamination. Results showed that P. aeruginosa is on average 300-fold more resistant when present on contaminated surfaces than in suspension. This increase in resistance agrees with results reported in studies of biofilms, but unexpectedly, it precedes biofilm formation. The surface to which bacteria are attached can influence the effectiveness of disinfectants. Viable bacteria attached to devices may require dislodging through more than a one-step method for detection. The data, obtained with a sensitive and quantitative test, suggest that disinfectants are less effective on contaminated surfaces than generally acknowledged.

An integrated study on antimicrobial activity and ecotoxicity of quantum dots and quantum dots coated with the antimicrobial peptide indolicidin.

Science.gov (United States)

Galdiero, Emilia; Siciliano, Antonietta; Maselli, Valeria; Gesuele, Renato; Guida, Marco; Fulgione, Domenico; Galdiero, Stefania; Lombardi, Lucia; Falanga, Annarita

This study attempts to evaluate the antimicrobial activity and the ecotoxicity of quantum dots (QDs) alone and coated with indolicidin. To meet this objective, we tested the level of antimicrobial activity on Gram-positive and Gram-negative bacteria, and we designed an ecotoxicological battery of test systems and indicators able to detect different effects using a variety of end points. The antibacterial activity was analyzed against Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 1025), Escherichia coli (ATCC 11229), and Klebsiella pneumoniae (ATCC 10031), and the results showed an improved germicidal action of QDs-Ind. Toxicity studies on Daphnia magna indicated a decrease in toxicity for QDs-Ind compared to QDs alone, lack of bioluminescence inhibition on Vibrio fisheri, and no mutations in Salmonella typhimurium TA 100. The comet assay and oxidative stress experiments performed on D. magna showed a genotoxic and an oxidative damage with a dose-response trend. Indolicidin retained its activity when bound to QDs. We observed an enhanced activity for QDs-Ind. The presence of indolicidin on the surface of QDs was able to decrease its QDs toxicity.

Comparative study of inactivation of herpes simplex virus types 1 and 2 by commonly used antiseptic agents

International Nuclear Information System (INIS)

Croughan, W.S.; Behbehani, A.M.

1988-01-01

A comparative study of the different reactions of herpes simplex virus types 1 and 2 to Lysol, Listerine, bleach, rubbing alcohol, Alcide disinfectant (Alcide Corp., Westport, Conn.), and various pHs, temperatures, and UV light exposures was performed. Both types of stock virus (titers of approximately 10(6) and 10(5.5) for types 1 and 2, respectively) were inactivated by 0.5% Lysol in 5 min; by Listerine (1:1 mixtures) in 5 min; by 2000 ppm (2000 microliters/liter) of bleach in 10 min; by rubbing alcohol (1:1 mixtures) at zero time; by Alcide disinfectant (0.2 ml of virus plus 2.0 ml of Alcide) at zero time; by pHs 3, 5, and 11 in 10 min; and by a temperature of 56 degrees C in 30 min. A germicidal lamp at a distance of 48 cm failed to completely inactivate the two types in 15 min. Type 1 showed slightly more resistance to Listerine and bleach and significantly more resistance to heat; moreover, pH 9 did not affect the infectivity of either type after 10 min

High-performance, low-cost solar collectors for disinfection of contaminated water.

Science.gov (United States)

Vidal, A; Diaz, A I

2000-01-01

Although the germicidal action of sunlight has long been recognized, its potential for practical applications has to be researched more thoroughly. This paper summarizes the progress made toward a commercially practical collector for solar disinfection applications. Nontracking compound parabolic collectors (CPCs), developed originally for capturing solar photons for thermal energy applications, were examined as potential solar photoreactors. A field demonstration of solar disinfection treatment using commercially manufactured solar reactors was conducted. Field tests showed successful destruction of Escherichia coli and Enterococcus faecalis and have provided data for full-scale design of water treatment systems. From above observations, a throughput value of 50 L/m2 h for the low-cost CPC reactor tested was estimated. For a 190 m3/d (0.05 MGD) facility, the estimated total costs for disinfection using UV-A is U.S. $0.19/m3 ($0.70/1000 gal). The use of near-UV sunlight to disinfect water supplies seems promising in rural communities of developing countries where treated water is unavailable.

The effect of salinity, light and temperature in a disposal environment on the recovery of E. coli following exposure to ultraviolet radiation

International Nuclear Information System (INIS)

Chan, Y.Y.; Killick, E.G.

1995-01-01

The rates of recovery of E.coli previously exposed to a sub-lethal dose of germicidal u.v. radiation have been investigated. The influence of salinity and temperature on both the rates of dark repair and photoreactivation were investigated in order to assess the relative recovery of disinfected effluent released into coastal waters. The photoreactivation rates followed an Arrhenius relationship for samples reactivated in an isotonic medium and reached a maximum of 52% recovery of the viable cell count present before u.v. treatment. For those cells in a saline environment reactivation was slower and a lower maximum recovery was obtained. Dark repair rates were extremely limited in those cells exposed to the saline environment which was produced from synthetic sea water. A maximum recovery of 8% over a nine hour period was achieved. It is concluded that less reactivation by E.coli is likely within u.v. treated effluent disposed of into coastal environments. The levels of reactivation are however dependent upon the temperature and salinity of those waters. (author)

Effectiveness of UV-C light irradiation on disinfection of an eSOS(®) smart toilet evaluated in a temporary settlement in the Philippines.

Science.gov (United States)

Zakaria, Fiona; Harelimana, Bertin; Ćurko, Josip; van de Vossenberg, Jack; Garcia, Hector A; Hooijmans, Christine Maria; Brdjanovic, Damir

2016-01-01

Ultraviolet germicidal (short wavelength UV-C) light was studied as surface disinfectant in an Emergency Sanitation Operation System(®) smart toilet to aid to the work of manual cleaning. The UV-C light was installed and regulated as a self-cleaning feature of the toilet, which automatically irradiate after each toilet use. Two experimental phases were conducted i.e. preparatory phase consists of tests under laboratory conditions and field testing phase. The laboratory UV test indicated that irradiation for 10 min with medium-low intensity of 0.15-0.4 W/m(2) could achieve 6.5 log removal of Escherichia coli. Field testing of the toilet under real usage found that UV-C irradiation was capable to inactivate total coliform at toilet surfaces within 167-cm distance from the UV-C lamp (UV-C dose between 1.88 and 2.74 mW). UV-C irradiation is most effective with the support of effective manual cleaning. Application of UV-C for surface disinfection in emergency toilets could potentially reduce public health risks.

Ultraviolet radiation: the eye

International Nuclear Information System (INIS)

Cesarini, J.P.; Sliney, D.H.

1996-01-01

Under most conditions, the eye is well adapted to protect itself against ultraviolet radiation encountered in the outdoor environment as a result of the exposure geometry of the sun. Only when snow is on the ground does one experience acute effects of UV sunlight exposure (i.e. snow blindness, or photokeratitis). With regard to artificial sources, there are many occasions where one views bright light sources such as tungsten-halogen lamps, arc lamps and welding arcs. Such viewing is normally only momentary because of the aversion response to bright light and due to discomfort glare. However, such an aversion does not take place for germicidal lamps and other UV lamps which do not contain a strong visible component in their spectrum. The adverse effects from viewing such sources has been studied for decades and during the last two decades guidelines for limiting exposure to protect the eye have been developed. The guidelines were fostered to a large extent by the growing use of lasers and the quickly recognized hazard posed by viewing laser sources. (author)

Human exposure to ultraviolet radiation

International Nuclear Information System (INIS)

Bernhardt, J.H.; Matthes, R.

1987-01-01

Ultraviolet radiation is that part of the electromagnetic spectrum located between the softest ionizing radiation and visible radiation. The lower limit of 100 nm is equivalent to photon energies of 12.4 eV, which corresponds approximately to the limit for the production of ionization in biologically important materials. A historical subdividing of the UV-region takes some of the biological effects into account. In this arrangement the range 400-315 nm, the so-called black light region, is called UV-A. In this wavelength region, fluorescence can be induced in many substances. UV-B covers the range 315-280 nm (the skin erythemal region). Most of the biologically active and potentially harmful UV from the sun reaching the surface of the earth is part of this spectral region. UV-C includes the radiation of wavelengths less than 280 nm (the germicidal region). It should be noted that this classification is somewhat arbitrary, and today it is more usual to evaluate the biological effectiveness of the whole UV-range from 200 to 400 nm

Decontamination Efficacy of Ultraviolet Radiation against Biofilms of Common Nosocomial Bacteria.

Science.gov (United States)

Tingpej, Pholawat; Tiengtip, Rattana; Kondo, Sumalee

2015-06-01

Ultraviolet radiation (UV) is commonly used to destroy microorganisms in the health-care environment. However, the efficacy of UV radiation against bacteria growing within biofilms has never been studied. To measure the sterilization effectiveness of UV radiation against common healthcare associated pathogens growing within biofilms. Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Streptococcus epidermidis, Escherichia coli, ESBL-producing E. coli, Pseudomonas aeruginosa and Acinetobacter baumannii were cultivated in the Calgary Biofilm Device. Their biofilms were placed 50 cm from the UV lamp within the Biosafety Cabinet. Viability test, crystal violet assay and a scanning electron microscope were used to evaluate the germicidal efficacy. Within 5 minutes, UV radiation could kill S. aureus, MRSA, S. epidermidis, A. baumannii and ESBL-producing E. coli completely while it required 20 minutes and 30 minutes respectively to kill E. coli and P. aeruginosa. However, the amounts of biomass and the ultrastructure between UV-exposed biofilms and controls were not significantly different. UV radiation is effective in inactivating nosocomial pathogens grown within biofilms, but not removing biofilms and EPS. The biofilm of P. aeruginosa was the most durable.

Fruit-Enhanced Resistance to Microbial Infection Induced by Selective Laser Excitation

Directory of Open Access Journals (Sweden)

Alicia G. Gonzálvez

2013-01-01

Full Text Available Table grapes were irradiated with laser pulses at two different wavelengths: one selected at 302.1 nm, that is, resonant with the transresveratrol biphoton absorption band, and another selected at 300 nm, that is a nonresonant wavelength where trans-resveratrol two-photon absorption is negligible. Attenuated total reflectance Fourier transformed infrared spectroscopic analyses of the irradiated grapes' skin showed an enhancement of polyphenols' content when the resonant wavelength was employed. Furthermore, microbiological analysis performed with nontreated (control, nonresonant, and resonantly irradiated grapes demonstrated how the last samples developed a significantly lower number of colony forming units. Since the only difference between the two (resonant and nonresonant irradiation conditions was just a couple of nanometres in the employed UV-B laser wavelengths, the germicidal effect should be considered very similar. As a result, the observed difference in the table grape resistance to microbial infection was attributed to a wavelength-dependent-induced photochemistry. Finally, the potentiality of this method to enhance the postharvest health status of table grapes is remarked.

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.

Development of a new water sterilization device with a 365 nm UV-LED.

Science.gov (United States)

Mori, Mirei; Hamamoto, Akiko; Takahashi, Akira; Nakano, Masayuki; Wakikawa, Noriko; Tachibana, Satoko; Ikehara, Toshitaka; Nakaya, Yutaka; Akutagawa, Masatake; Kinouchi, Yohsuke

2007-12-01

Ultraviolet (UV) irradiation is an effective disinfection method. In sterilization equipment, a low-pressure mercury lamp emitting an effective germicidal UVC (254 nm) is used as the light source. However, the lamp, which contains mercury, must be disposed of at the end of its lifetime or following damage due to physical shock or vibration. We investigated the suitability of an ultraviolet light-emitting diode at an output wavelength of 365 nm (UVA-LED) as a sterilization device, comparing with the other wavelength irradiation such as 254 nm (a low-pressure mercury lam) and 405 nm (LED). We used a commercially available UVA-LED that emitted light at the shortest wavelength and at the highest output energy. The new sterilization system using the UVA-LED was able to inactivate bacteria, such as Escherichia coli DH5 alpha, Enteropathogenic E. coli, Vibrio parahaemolyticus, Staphylococcus aureus, and Salmonella enterica serovar Enteritidis. The inactivations of the bacteria were dependent on the accumulation of UVA irradiation. Taking advantage of the safety and compact size of LED devices, we expect that the UVA-LED sterilization device can be developed as a new type of water sterilization device.

Ozonated water in the post-harvest treatment of coffee fruits

Directory of Open Access Journals (Sweden)

Fernando J. B. Brandão

Full Text Available ABSTRACT Ozone is used in many countries for the treatment of effluents, becoming a viable alternative in sanitation of coffee wastewater. However, the strong ozone oxidation, responsible for its germicidal effect, can also compromise grain and beverage quality. The objective of this study was to evaluate the quality of Arabica coffee in different periods of treatment with ozonated water and its effect after drying. Coffee fruits were subjected to ozonation at regular intervals of 0, 5, 10, 20, and 30 min, with continuous stirring promoted by a recirculating water system at constant rate of 1 ppm of solubilized ozone. The design was completely randomized with five treatments and four replicates. After obtaining the data, the analysis of variance was performed and means were compared by Tukey test (p ≤ 0.05. The results showed a partial reduction of fungi after washing with ozonated water, but the same effect was not observed after drying. For coffee quality analysis, the longest times of exposure to the solubilized gas in the water produced some negative results in electrical conductivity and total and reducing sugars. However, the sensory quality of the beverage was maintained.

Radiopasteurization of sawdust media used in propagation of mushrooms

International Nuclear Information System (INIS)

Ito, Hitoshi; Sato, Tomotaro

1975-01-01

In our country, cultivation of mushrooms such as Pleurotus ostreatus, Kuehneromyces nameko, and Lentinus edodes (Cortinellus shiitake) are expanding, and has reached considerable amounts. These mushrooms are cultivated generally on decaying logs of broad leaf trees. Recently, these mushrooms are also cultivated artificially on the sawdust-media containing rice bran and other nutrient in the room of which temperature is controlled. However, these artificial culture media must be germicidated for 2 or 6 hours at 100 to 120 0 C before inoculation of mushroom spawn. In this study, attempts were made to cultivate Pleurotus ostreatus on the sawdust-media pasteurized by ionizing radiation. Inhibition of mushrooms growth were caused mainly by multiplication of Citrobacter and Fusarium, and these organisms were eliminated by a dose of 0.5 Mrad gamma irradiation. A surprising result was that many of sawdust media subjected to 0.5, 1.0 and 2.0 Mrad increased mycelial growth rates more than heat treatments, and also mushroom yields were enhanced. The multiplication of remaining microorganisms such as Bacillus and yeasts after irradiation with a dose of 0.5 Mrad or 1.0 Mrad did not inhibit the mycelial growth of mushrooms. (auth.)

Deactivation of Escherichia coli in a post-discharge chamber coupled to an atmospheric pressure multi-electrode DBD plasma source

International Nuclear Information System (INIS)

Pérez-Ruiz, V H; López-Callejas, R; De la Piedad Beneitez, A; Peña-Eguiluz, R; Mercado-Cabrera, A; Muñoz-Castro, A E; Barocio, S R; Valencia-Alvarado, R; Rodríguez-Méndez, B G

2012-01-01

Experimental results from applying a room pressure RF multi-electrode DBD plasma source to the inhibition of the population growth of Gram negative Escherichia coli (E. coli) within a post-discharge reactor are reported. The sample to be treated is deposited in the post-discharge chamber at about 50 mm from the plasma source outlet. Thus, the active species generated by the source are conveyed toward the chamber by the working gas flow. The plasma characterization included the measurement of the axial temperature at different distances from the reactor outlet by means of a K-type thermocouple. The resulting 294 K to 322 K temperature interval corresponded to distances between 10 mm to 1 mm respectively. As the material under treatment is placed further away, any thermal damage of the sample by the plasma is prevented. The measurement and optimization of the ozone O 3 concentration has also been carried out, provided that this is an active specie with particularly high germicide power. The effectiveness treatment of the E. coli bacteria growth inhibition by the proposed plasma source reached 99% when a 10 3 CFU/mL concentration on an agar plate had been exposed during ten minutes.

Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

International Nuclear Information System (INIS)

Chevremont, A.-C.; Farnet, A.-M.; Coulomb, B.; Boudenne, J.-L.

2012-01-01

Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO 2 . - Highlights: ► We test UV-LEDs as an urban wastewater tertiary treatment. ► UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. ► Coupled wavelengths have the most efficient bactericidal effect. ► Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

Methods for air cleaning and protection of building occupants from airborne pathogens

Energy Technology Data Exchange (ETDEWEB)

Bolashikov, Z.D.; Melikov, A.K. [International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Nils Koppels Alle, building 402, 2800 Lyngby (Denmark)

2009-07-15

This article aims to draw the attention of the scientific community towards the elevated risks of airborne transmission of diseases and the associated risks of epidemics or pandemics. The complexity of the problem and the need for multidisciplinary research is highlighted. The airborne route of transmission, i.e. the generation of pathogen laden droplets originating in the respiratory tract of an infected individual, the survivability of the pathogens, their dispersal indoors and their transfer to a healthy person are reviewed. The advantages and the drawbacks of air dilution, filtration, ultraviolet germicidal irradiation (UVGI), photocatalytic oxidation (PCO), plasmacluster ions and other technologies for air disinfection and purification from pathogens are analyzed with respect to currently used air distribution principles. The importance of indoor air characteristics, such as temperature, relative humidity and velocity for the efficiency of each method is analyzed, taking into consideration the nature of the pathogens themselves. The applicability of the cleaning methods to the different types of total volume air distribution used at present indoors, i.e. mixing, displacement and underfloor ventilation, as well as advanced air distribution techniques (such as personalized ventilation) is discussed. (author)

Assessing the in vivo impact of a gel sanitizer on the epidermal "barrier" dynamics

Directory of Open Access Journals (Sweden)

Henrique Silva

2015-03-01

Full Text Available Disease prevention and control depend on hand washing, in particular during epidemic surges (e.g. flu. The use of alcohol-based hand sanitizers is strongly recommended due to its high germicide effectiveness. However, its impact on skin physiology, especially on the barrier function, has not been determined, although most of the formulations include different humectants. This study evaluates the impact of a commercially available formulation on in vivo epidermal barrier dynamics. 13 young adult subjects (21.6 ± 2.6 years old were selected after informed consent. Subjects were asked to apply a commercially available alcohol gel sanitizer to one hand for 15 days. TEWL absolute values were measured on days 1, 8 and 15 and a plastic occlusion stress test (POST applied. Evaporation half-life (t1/2 evap and dynamic water mass (DWM values increased significantly on day 15 on the treated hand compared to the control hand suggesting that, in the present experimental conditions, the regular use of an alcohol-based gel sanitizer does changes the epidermal barrier. This study also confirms the usefulness of this kinetic model to detect subtle changes on in vivo TEWL dynamics.

Sterilization of swine wastewater treated by anaerobic reactors using UV photo-reactors

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Erlon Lopes Pereira

2014-09-01

Full Text Available The use of ultraviolet radiation is an established procedure with growing application forthe disinfection of contaminated wastewater. This study aimed to evaluate the efficiency of artificial UV radiation, as a post treatment of liquid from anaerobic reactors treating swine effluent. The UV reactors were employed to sterilize pathogenic microorganisms. To this end, two photo-reactors were constructed using PVC pipe with100 mm diameter and 1060 mmlength, whose ends were sealed with PVC caps. The photo-reactors were designed to act on the liquid surface, as the lamp does not get into contact with the liquid. To increase the efficiency of UV radiation, photo-reactors were coated with aluminum foil. The lamp used in the reactors was germicidal fluorescent, with band wavelength of 230 nm, power of 30 Watts and manufactured by Techlux. In this research, the HRT with the highest removal efficiency was 0.063 days (90.6 minutes, even treating an effluent with veryhigh turbidity due to dissolved solids. It was concluded that the sterilization method using UV has proved to be an effective and appropriate process, among many other procedures.

The effects of ultraviolet radiation exposure of adjacent cells on plaque formation with Herpes simplex virus type 1

International Nuclear Information System (INIS)

Conner, R.E.; Coohill, T.P.; Babich, M.A.

1987-01-01

African green monkey kidney cells (CV-1P) were exposed to low fluences of 254 nm germicidal radiation and then infected with Herpes simplex virus, type I. The result of this treatment was an increase in viral plaque development rate, the large plaque effect (LPE). A measurement of the kinetics of plaque development suggested that a large portion of the effect could be due to events occurring in those cells that are adjacent to the initially infected cell. An infectious center assay was employed in order to isolate the effects of ultraviolet radiation (UV) on the initially infected cells from those effects on the adjacent cells that became infected as the plaque spread radially outward. Plaque development began earlier in UV irradiated cells and progressed at a uniformly accelerated rate compared to untreated cells. Results indicate that although the initially infected cell contributes to the LPE, the major effect is due to events that occur in the adjacent cells. Each round of viral replication appears to contribute equally to the LPE. The virally induced rate of fusion of the initially infected cell with its immediate neighbors is not affected by UV. (author)

Screening of some commonly used skin-lightening creams and soaps: a case study in Ghana

International Nuclear Information System (INIS)

Beni, C.T.; Maaku, B.T.; Akaho, E.H.K.

2003-01-01

Seven commonly used skin lightening creams (Body Claire, Peau claire, Akagni sivoclaire, Top gel, Tenovate and Movate) and five medicated soaps (Tura, Sukisa Bango, Crusader Safety, Movate Germicidal and Silver Rose) were investigated for the presence and levels of trace/heavy metals and hydroquinone in them. Instrumental Neutron Activation analysis (INAA) was used to identify and quantify the level of trace/heavy metals in these creams and soap samples. The analysis showed the presence in the creams of significant concentrations of Mn, Cd, Au, Sn, In, Sc, Hf, Ta, Ba, Nd, Sb, Al and Co. The medicated soaps contained significant concentrations of Hg, Co, Ce, Al, Hf and Ti. Thin Layer Chromatography (TLC) investigations revealed the presence of hydroquinones in Akagni and confirmed its presence also in Body Claire, Peau Claire and Sivoclaire but its absence in Tenovate, Top gel and Movate creams. Titration of the creams against Ce (IV) solution showed that hydroquinone levels in the Body Claire is 2.47%. Akagni is 4.92%, Peau Claire is 3.84% and Sivoclaire contains 4.03%. These levels are higher than the maximum 2% allowed by the Ghana Standards Board, the EEC directives of 1976 and the Cosmetic Production Regulation 1978 (UK) for product safety. (author)

Stability study of azithromycin in ophthalmic preparations

Directory of Open Access Journals (Sweden)

Andréia de Haro Moreno

2009-06-01

Full Text Available A stability study of azithromycin in ophthalmic preparations was developed by submission to different types of light, temperature and pH, using the biodiffusion assay (cylinder 3 x 3 for the quantifications. Bacillus subtilis, ATCC 9372, was used as test organism. The used concentration range was of 50 to 200 µg/mL. The study demonstrated that the drug suffered degradation when submitted to the ultraviolet light, germicide light, solar luminosity, acid solution, basic solution and hydrogen peroxide solution. The results were analyzed by the analysis of variance (ANOVA.O estudo de estabilidade de azitromicina em preparações oftálmicas foi realizado após exposição a diferentes tipos de luz, temperatura e pH, utilizando o método de difusão em ágar (cilindros 3 x 3 para as quantificações. A faixa de concentração foi de 50 a 200 µg/mL. O estudo demonstrou que o fármaco sofreu degradação quando submetido às luzes ultravioleta, germicida e solar, e a soluções ácida, alcalina e de peróxido de hidrogênio. Os resultados foram analisados através da análise da variância (ANOVA.

Pulsed dielectric barrier discharge for Bacillus subtilis inactivation in water

Science.gov (United States)

Hernández-Arias, A. N.; Rodríguez-Méndez, B. G.; López-Callejas, R.; Valencia-Alvarado, R.; Mercado-Cabrera, A.; Peña-Eguiluz, R.; Barocio, S. R.; Muñoz-Castro, A. E.; de la Piedad Beneitez, A.

2012-06-01

The inactivation of Bacillus subtilis bacteria in water has been experimentally studied by means of a pulsed dielectric barrier discharge (PDBD) in a coaxial reactor endowed with an alumina dielectric. The plasma source is capable of operating at atmospheric pressure with gas, water or hybrid gas-liquid media at adjustable 25 kV pulses, 30 μs long and at a 500 Hz frequency. In order to evaluate the inactivation efficiency of the system, a set of experiments were designed on the basis of oxygen flow control. The initial data have showed a significant bacterial rate reduction of 103-107 CFU/mL. Additional results proved that applying an oxygen flow for a few seconds during the PDBD treatment inactivates the Bacillus subtilis population with 99.99% effectiveness. As a reference, without gas flow but with the same exposure times, this percentage is reduced to ~90%. The analysis of the relationship between inactivation rate and chemical species in the discharge has been carried out using optical emission spectroscopy as to identifying the main reactive species. Reactive oxygen species such as atomic oxygen and ozone tuned out to be the dominant germicidal species. Some proposed inactivation mechanisms of this technique are discussed.

Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

Energy Technology Data Exchange (ETDEWEB)

Chevremont, A.-C., E-mail: anne-celine.chevremont@imbe.fr [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France); Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Farnet, A.-M. [Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Coulomb, B.; Boudenne, J.-L. [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France)

2012-06-01

Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO{sub 2}. - Highlights: Black-Right-Pointing-Pointer We test UV-LEDs as an urban wastewater tertiary treatment. Black-Right-Pointing-Pointer UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. Black-Right-Pointing-Pointer Coupled wavelengths have the most efficient bactericidal effect. Black-Right-Pointing-Pointer Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

Reduction of patulin in apple cider by UV radiation.

Science.gov (United States)

Dong, Qingfang; Manns, David C; Feng, Guoping; Yue, Tianli; Churey, John J; Worobo, Randy W

2010-01-01

The presence of the mycotoxin patulin in processed apple juice and cider presents a continual challenge to the food industry as both consumer health and product quality issues. Although several methods for control and/or elimination of patulin have been proposed, no unifying method has been commercially successful for reducing patulin burdens while maintaining product quality. In the present study, exposure to germicidal UV radiation was evaluated as a possible commercially viable alternative for the reduction and possible elimination of the patulin mycotoxin in fresh apple cider. UV exposure of 14.2 to 99.4 mJ/cm(2) resulted in a significant and nearly linear decrease in patulin levels while producing no quantifiable changes in the chemical composition (i.e., pH, Brix, and total acids) or organoleptic properties of the cider. For the range of UV doses tested, patulin levels decreased by 9.4 to 43.4%; the greatest reduction was achieved after less than 15 s of UV exposure. The method of UV radiation (the CiderSure 3500 system) is an easily implemented, high-throughput, and cost-effective method that offers simultaneous UV pasteurization of cider and juice products and reduction and/or elimination of patulin without unwanted alterations in the final product.

Synergistic Antimicrobial Effect of Tribulus terrestris and Bitter Almond Extracts

Directory of Open Access Journals (Sweden)

Hamid Abtahi

2014-12-01

Full Text Available Background: The antimicrobial effects of the extracts of different kinds of plants have been demonstrated in several studies. However, no study has been conducted so far on the synergistic effects of two herbal extracts on their germicidal effects. In this study, in addition to antibacterial effects of the aqueous, methanol or ethanol extracts of Tribulus terrestris and bitter almond on some bacteria, the synergistic effects of the extracts of these two plants were also evaluated. Materials and Methods: In this experimental study, water, methanol and ethanol extracts of seeds were screened against some bacterial strains. Seeds were extracted by percolation method. Aliquots of the extracts at variable concentrations were then incubated with different bacterial strains, and the antimicrobial activities of the extracts from seeds were determined by MIC. Three antibiotics were used as reference compounds for antibacterial activities. Seeds extract inhibited significantly the growth of the tested bacterial strains. Results: The greatest synergistic effect of T. terrestris and bitter almond extracts is detected in methanol and aqueous extracts. Among the bacterial strains tested, Staphylococcus aureus was most susceptibility. Conclusion: The results showed the highest antibacterial effect in the combination of methanol extract of T. terrestris and the aqueous extract of the bitter almond.

Deep UV patterning of acrylic masters for molding biomimetic dry adhesives

International Nuclear Information System (INIS)

Sameoto, D; Menon, C

2010-01-01

We present a novel fabrication method for the production of biomimetic dry adhesives that allows enormous variation in fiber shapes and sizes. The technology is based on deep-UV patterning of commercial acrylic with semi-collimated light available from germicidal lamps, and combined careful processing conditions, material selection and novel developer choices to produce relatively high-aspect-ratio fibers with overhanging caps on large areas. These acrylic fibers are used as a master mold for subsequent silicone rubber negative mold casting. Because the bulk acrylic demonstrates little inherent adhesion to silicone rubbers, the master molds created in this process do not require any surface treatments to achieve high-yield demolding of interlocked structures. Multiple polymers can be cast from silicone rubber negative molds and this process could be used to structure smart materials on areas over multiple square feet. Using direct photopatterning of acrylic allows many of the desired structures for biomimetic dry adhesives to be produced with relative ease compared to silicon-based molding processes, including angled fibers and hierarchical structures. Optimized fiber shapes for a variety of polymers can be produced using this process, and adhesion measurements on a well-characterized polyurethane, ST-1060, are used to determine the effect of fiber geometry on adhesion performance

Pulsed dielectric barrier discharge for Bacillus subtilis inactivation in water

International Nuclear Information System (INIS)

Hernández-Arias, A N; López-Callejas, R; De la Piedad Beneitez, A; Rodríguez-Méndez, B G; Valencia-Alvarado, R; Mercado-Cabrera, A; Peña-Eguiluz, R; Barocio, S R; Muñoz-Castro, A E

2012-01-01

The inactivation of Bacillus subtilis bacteria in water has been experimentally studied by means of a pulsed dielectric barrier discharge (PDBD) in a coaxial reactor endowed with an alumina dielectric. The plasma source is capable of operating at atmospheric pressure with gas, water or hybrid gas-liquid media at adjustable 25 kV pulses, 30 μs long and at a 500 Hz frequency. In order to evaluate the inactivation efficiency of the system, a set of experiments were designed on the basis of oxygen flow control. The initial data have showed a significant bacterial rate reduction of 10 3 -10 7 CFU/mL. Additional results proved that applying an oxygen flow for a few seconds during the PDBD treatment inactivates the Bacillus subtilis population with 99.99% effectiveness. As a reference, without gas flow but with the same exposure times, this percentage is reduced to ∼90%. The analysis of the relationship between inactivation rate and chemical species in the discharge has been carried out using optical emission spectroscopy as to identifying the main reactive species. Reactive oxygen species such as atomic oxygen and ozone tuned out to be the dominant germicidal species. Some proposed inactivation mechanisms of this technique are discussed.

Transmission of UV-irradiance into nectarine fruit

International Nuclear Information System (INIS)

Blanke, M.M.

1996-01-01

With the global depletion of the ozone layer, leaves and fruits are increasingly exposed to UV-irradiance on the tree. Some fruits are additionally exposed postharvest to artificial germicidal W-irradiance, leading to a cumulative effect. This paper examines the transmission of UV-light (200-400 nm) by the peel of ripe nectarine fruit using UV/VIS spectrophotometry to aid understanding of UV-effects and assess the sensitivity of the peel to UV wavelengths. Yellow peel of nectarine fruit transmitted less than 0.1 % in the UV-C range of 220 to 280 nm. With longer wavelenghts, UV-light transmission increased slowly from 0.4 % at 284 nm to 1.6 % at 320 nm and, in the UV-A region, progressively from 1.9 % at 330 nm to a maximum of 13 % of incident irradiance at 400 nm. Red peel of nectarine fruit transmitted less than 0.1 % of UV-C and UV-B light, but up to 0.9 % of incident UV-A light at 400 nm. Conversely, UV-absorption of nectarine peel decreased with longer wavelengths. Hence, fruit parenchyma is more affected by UV-irradiance at wavelengths above ca. 280 nm and underneath yellow than underneath red peel

Post-UV colony-forming ability of normal fibroblast strains and of the xeroderma pigmentosum group G strain

International Nuclear Information System (INIS)

Barrett, S.F.; Tarone, R.E.; Moshell, A.N.; Ganges, M.B.; Robbins, J.H.

1981-01-01

In xeroderma pigmentosum, an inherited disorder of defective DNA repair, post-uv colony-forming ability of fibroblasts from patients in complementation groups A through F correlates with the patients' neurological status. The first xeroderma pigmentosum patient assigned to the recently discovered group G had the neurological abnormalities of XP. Researchers have determined the post-uv colony-forming ability of cultured fibroblasts from this patient and from 5 more control donors. Log-phase fibroblasts were irradiated with 254 nm uv light from a germicidal lamp, trypsinized, and replated at known densities. After 2 to 4 weeks' incubation the cells were fixed, stained and scored for colony formation. The strains' post-uv colony-forming ability curves were obtained by plotting the log of the percent remaining post-uv colony-forming ability as a function of the uv dose. The post-uv colony-forming ability of 2 of the 5 new normal strains was in the previously defined control donor zone, but that of the other 3 extended down to the level of the most resistant xeroderma pigmentosum strain. The post-uv colony-forming ability curve of the group G fibroblasts was not significantly different from the curves of the group D fibroblast strains from patients with clinical histories similar to that of the group G patient

Potential of UVC germicidal irradiation in suppressing crown rot disease, retaining postharvest quality and antioxidant capacity of Musa AAA "Berangan" during fruit ripening.

Science.gov (United States)

S Mohamed, Nuratika Tamimi; Ding, Phebe; Kadir, Jugah; M Ghazali, Hasanah

2017-09-01

Crown rot caused by fungal pathogen is the most prevalent postharvest disease in banana fruit that results significant economic losses during transportation, storage, and ripening period. Antifungal effects of ultraviolet C (UVC) irradiation at doses varied from 0.01 to 0.30 kJ m -2 were investigated in controlling postharvest crown rot disease, maintenance of fruit quality, and the effects on antioxidant capacity of Berangan banana fruit during ripening days at 25 ± 2°C and 85% RH. Fruits irradiated with 0.30 kJ m -2 exhibited the highest (i.e., 62.51%) reduction in disease severity. However, the application of UVC at all doses caused significant browning damages on fruit peel except the dose of 0.01 kJ m -2 . This dose synergistically reduced 46.25% development of postharvest crown and did not give adverse effects on respiration rate, ethylene production, weight loss, firmness, color changes, soluble solids concentration, titratable acidity, and pH in banana as compared to the other treatments and control. Meanwhile, the dose also enhanced a significant higher level of total phenolic content, FRAP, and DPPH values than in control fruits indicating the beneficial impact of UVC in fruit nutritional quality. The results of scanning electron micrographs confirmed that UVC irradiation retarded the losses of wall compartments, thereby maintained the cell wall integrity in the crown tissue of banana fruit. The results suggest that using 0.01 kJ m -2 UVC irradiation dose as postharvest physical treatment, the crown rot disease has potential to be controlled effectively together with maintaining quality and antioxidant of banana fruit.

Ultraviolet susceptibility of BCG and virulent tubercle bacilli

International Nuclear Information System (INIS)

Riley, R.L.; Knight, M.; Middlebrook, G.

1976-01-01

To test the effectiveness of irradiating the upper air of a room with ultraviolet light at reducing the concentration of airborne tubercle bacilli, the susceptibility to the germicidal effects of ultraviolet light, Z, was determined for various mycobacteria. Virulent tubercle bacilli and bacille Calmette-Guerin (BCG) were susceptible to ultraviolet radiation, whereas Mycobacterium phlei had 10 times their resistance (Z, approximately one-tenth that for M. tuberculosis). The effectiveness against BCG of upper air ultraviolet irradiation in a room was tested directly by nebulizing BCG into the air of the room and monitoring its rate of disappearance. With one 17-watt fixture operating, the rate of disappearance increased 6-fold; with 2 fixtures operating (46 watts total), the rate of disappearance increased 9-fold. This implies that under steady-state conditions, the concentrations of airborne organisms with ultraviolet light(s) on would have been one-sixth and one-ninth, respectively. The increase in rate of decay of the airborne organism using 1 fixture was equivalent to 10 air changes per hour, whereas that using 2 fixtures was approximately 25 air changes per hour (range: 18 to 33 air changes per hour). These increments are less than those reported previously for Serratia marcescens, because the Z value for BCG is approximately one-seventh that for serratia. These findings with BCG are believed to be directly applicable to virulent tubercle bacilli

Sampling polyhexamethylene guanidine aerosols using eosin Y-coated glass beads

International Nuclear Information System (INIS)

Choi, Sang Hyun; Park, Seon Kyung; Kang, Hyun Joong; Kwon, Jung Hwan; Lee, Kyu Hong

2015-01-01

Fatalities caused by the use of polyhexamethylene guanidine (PHMG), a general-purpose chemical germicide used as a humidifier disinfectant in Korea, have raised concerns about exposure to biocide aerosols in indoor environments. A sampler capable of accumulating PHMG from aqueous aerosols was developed as an alternative to low-volume air samplers. This sampler was prepared by placing glass beads coated with 2-(2,4,5,7-tetrabromo-6-oxido-3-oxo-3H-xanthen-9-yl)benzoate (Eosin Y) in a custom-made plastic holder. Passive sampling rates, measured in a bench-top exposure chamber at two different aqueous PHMG aerosol generation rates, were found to be independent of the experimental conditions. This suggests that the capacity of the sampler to accumulate the PHMG aerosol was sufficient for the sampling duration tested. However, the passive sampling rate was 7.6 × 10"−"6 m"3/h for the sampler area of 22 cm"2. This rate is lower than the typical human breathing rate and inadequate for quantitative instrumental analyses at low concentrations in indoor air. A 30-fold enhancement of the sampling rate was achieved by forced convection using a commercial battery-operated fan at ≥2000 rpm. With this accelerated sampling rate, the sampler could be used to monitor time-integrated concentrations of PHMG aerosols in the air

Evaluation of a pulsed xenon ultraviolet disinfection system to decrease bacterial contamination in operating rooms.

Science.gov (United States)

El Haddad, Lynn; Ghantoji, Shashank S; Stibich, Mark; Fleming, Jason B; Segal, Cindy; Ware, Kathy M; Chemaly, Roy F

2017-10-10

Environmental cleanliness is one of the contributing factors for surgical site infections in the operating rooms (ORs). To decrease environmental contamination, pulsed xenon ultraviolet (PX-UV), an easy and safe no-touch disinfection system, is employed in several hospital environments. The positive effect of this technology on environmental decontamination has been observed in patient rooms and ORs during the end-of-day cleaning but so far, no study explored its feasibility between surgical cases in the OR. In this study, 5 high-touch surfaces in 30 ORs were sampled after manual cleaning and after PX-UV intervention mimicking between-case cleaning to avoid the disruption of the ORs' normal flow. The efficacy of a 1-min, 2-min, and 8-min cycle were tested by measuring the surfaces' contaminants by quantitative cultures using Tryptic Soy Agar contact plates. We showed that combining standard between-case manual cleaning of surfaces with a 2-min cycle of disinfection using a portable xenon pulsed ultraviolet light germicidal device eliminated at least 70% more bacterial load after manual cleaning. This study showed the proof of efficacy of a 2-min cycle of PX-UV in ORs in eliminating bacterial contaminants. This method will allow a short time for room turnover and a potential reduction of pathogen transmission to patients and possibly surgical site infections.

Efficacy of Inactivation of Human Enteroviruses by Multiple ...

Science.gov (United States)

Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment applications, such as the inefficiency of energy consumption and more importantly potential mercury contamination upon disposal of the lamps. The recent invention of a novel light-emitting-diodes (LED) device generating germicidal UV wavelengths could eliminate the aforementioned limitations. In this study, we investigated the efficacy of multiple-wavelength UV LEDs for inactivating USEPA contaminant candidate list (CCL) RNA enteroviruses. Of 12 enterovirus species, serotype representatives of the four human enteric species (enterovirus A-D) such as coxsackievirus A10 (CVA10), echovirus 30 (Echo30), poliovirus 1 (PV1), and enterovirus 70 (EV70) respectively were selected as testing RNA viruses. Bench-scale performance evaluation was conducted using a collimated beam (CB) apparatus with LEDs emitting at 260 nm, 280 nm, and the combination of 260|280 nm together, as well as a monochromatic low-pressure (LP) UV lamp at 254 nm for comparison. The CB tests were performed with mixed stocks of four viruses. Infectious virus concentrations were determined using an integrated cell culture reverse transcriptase quantitative PCR (ICC-RTqPCR). The 260 nm LED was most effective at inactivating all enteroviruses teste

Enumeration and identification of gram negative bacteria present in soil underlying urban waste-sites in southwestern Nigeria.

Science.gov (United States)

Achudume, A C; Olawale, J T

2010-09-01

Samples of soils underlying wastes were collected from four sites representing four demographic regions of a medium sized town in southwestern Nigeria. Standard methods and reference strains of isolated bacteria were employed for identification. Evaluation of the enzymatic and biochemical reactions showed that all isolated and identified microbes were non-fermenting heterotrophic (HTB). For example, Klebsiella pnemuniae may be involved in wound infections, particularly following bowel surgery. Similarly Pseudomonas aeruginosa can produce serious nosocomial infections if it gains access to the body through wounds or intravenous lines. From the 15 culure plates, 88 colonies with various characteristics were enumerated. They differed in aspect of viscosity and color. The bacterial species were identified by percent positive reactions while oxidative and sugar fermentation tests revealed various characteristics among the isolated strains. All of the isolates were negative for citrate utilization, gelatin liquefaction, nitrate reduction, methyl red and Voges Proskaur, motility and hydrogen sulphate production. The quantity of HTB present in an area serves as an index of the general sanitary conditions of that area. The presence of a large number of HTB, in an ecological area may be considered a liability as it can enhance the spread of diseases and on a larger scale may enable epidemics to arise. Therefore, there is need for control of waste sites by recovery and regular germicidal sanitation.

'No touch' technologies for environmental decontamination: focus on ultraviolet devices and hydrogen peroxide systems.

Science.gov (United States)

Weber, David J; Kanamori, Hajime; Rutala, William A

2016-08-01

This article reviews 'no touch' methods for disinfection of the contaminated surface environment of hospitalized patients' rooms. The focus is on studies that assessed the effectiveness of ultraviolet (UV) light devices, hydrogen peroxide systems, and self-disinfecting surfaces to reduce healthcare-associated infections (HAIs). The contaminated surface environment in hospitals plays an important role in the transmission of several key nosocomial pathogens including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp., Clostridium difficile, Acinetobacter spp., and norovirus. Multiple clinical trials have now demonstrated the effectiveness of UV light devices and hydrogen peroxide systems to reduce HAIs. A limited number of studies have suggested that 'self-disinfecting' surfaces may also decrease HAIs. Many studies have demonstrated that terminal cleaning and disinfection with germicides is often inadequate and leaves environmental surfaces contaminated with important nosocomial pathogens. 'No touch' methods of room decontamination (i.e., UV devices and hydrogen peroxide systems) have been demonstrated to reduce key nosocomial pathogens on inoculated test surfaces and on environmental surfaces in actual patient rooms. Further UV devices and hydrogen peroxide systems have been demonstrated to reduce HAI. A validated 'no touch' device or system should be used for terminal room disinfection following discharge of patients on contact precautions. The use of a 'self-disinfecting' surface to reduce HAI has not been convincingly demonstrated.

Design of the environment of care for safety of patients and personnel: does form follow function or vice versa in the intensive care unit?

Science.gov (United States)

Bartley, Judene; Streifel, Andrew J

2010-08-01

We review the context of the environment of care in the intensive care unit setting in relation to patient safety and quality, specifically addressing healthcare-associated infection issues and solutions involving interdisciplinary teams. Issues addressed include current and future architectural design and layout trends, construction trends affecting intensive care units, and prevention of construction-associated healthcare-associated infections related to airborne and waterborne risks and design solutions. Specific elements include single-occupancy, acuity-scalable intensive care unit rooms; environmental aspects of hand hygiene, such as water risks, sink design/location, human waste management, surface selection (floor covering, countertops, furniture, and equipment) and cleaning, antimicrobial-treated or similar materials, ultraviolet germicidal irradiation, specialized rooms (airborne infection isolation and protective environments), and water system design and strategies for safe use of potable water and mitigation of water intrusion. Effective design and operational use of the intensive care unit environment of care must engage critical care personnel from initial planning and design through occupancy of the new/renovated intensive care unit as part of the infection control risk assessment team. The interdisciplinary infection control risk assessment team can address key environment of care design features to enhance the safety of intensive care unit patients, personnel, and visitors. This perspective will ensure the environment of care supports human factors and behavioral aspects of the interaction between the environment of care and its occupants.

Research and applications of N-halamine biocidal materials

Directory of Open Access Journals (Sweden)

KANG Zhenzhen

2012-10-01

Full Text Available N-halamines,a new class of biocides,overcome some of the disadvantages caused by the traditional biocides in practical applications.They are environmentally friendly germicides due to their fast and efficient sterilization,storage stability,and regeneration.Earlier studies on N-halamines mainly focused on the syntheses and applications of small molecular organic N-halamines such as fivemembered and six-membered heterocyclic N-halamine compounds.Compared to traditional inorganic halogen-containing disinfectants such as chlorine gas,sodium hypochlorite,chlorine dioxide,these heterocyclic N-halamines can maintain disinfection capacity in the water for longer time due to their better stability.Since the late 20th century,non-leaching biocial N-halamine materials have received much attention.Some novel N-halmine precursors with binding groups have been covalently bounded to various materials such as cellulose fiber,silica gel,polystyrene,polyethylene,and polyurethane to produce nonleaching biocidal materials.Specially,the successful development of macroporous cross-linked N-halamine polymer resin materials (Halopure and related technologies created a new era for the applications of N-halamine materials in the disinfection of drinking water.In this review paper,the antibacterial mechanism and synthetic methods of N-halamine biocidal materials and their application prospects in various fields of daily life were introduced.Their development prospects were also made.

Efficacy of ultraviolet radiation as an alternative technology to inactivate microorganisms in grape juices and wines.

Science.gov (United States)

Fredericks, Ilse N; du Toit, Maret; Krügel, Maricel

2011-05-01

Since sulphur dioxide (SO(2)) is associated with health risks, the wine industry endeavours to reduce SO(2) levels in wines with new innovative techniques. The aim of this study was, therefore, to investigate the efficacy of ultraviolet radiation (UV)-C (254 nm) as an alternative technology to inactivate microorganisms in grape juices and wines. A pilot-scale UV-C technology (SurePure, South Africa) consisting of an UV-C germicidal lamp (100 W output; 30 W UV-C output) was used to apply UV-C dosages ranging from 0 to 3672 J l(-1), at a constant flow rate of 4000 l h(-1) (Re > 7500). Yeasts, lactic and acetic acid bacteria were singly and co-inoculated into 20 l batches of Chenin blanc juice, Shiraz juice, Chardonnay wine and Pinotage wine, respectively. A dosage of 3672 J l(-1), resulted in an average log(10) microbial reduction of 4.97 and 4.89 in Chardonnay and Pinotage, respectively. In Chenin blanc and Shiraz juice, an average log(10) reduction of 4.48 and 4.25 was obtained, respectively. UV-C efficacy may be influenced by liquid properties such as colour and turbidity. These results had clearly indicated significant (p radiation may stabilize grape juice and wine microbiologically in conjunction with reduced SO(2) levels. Copyright © 2010 Elsevier Ltd. All rights reserved.

Sampling polyhexamethylene guanidine aerosols using eosin Y-coated glass beads

Energy Technology Data Exchange (ETDEWEB)

Choi, Sang Hyun; Park, Seon Kyung; Kang, Hyun Joong; Kwon, Jung Hwan [Korea University, Seoul (Korea, Republic of); Lee, Kyu Hong [Korea Institute of Toxicology, Jeongeup (Korea, Republic of)

2015-07-15

Fatalities caused by the use of polyhexamethylene guanidine (PHMG), a general-purpose chemical germicide used as a humidifier disinfectant in Korea, have raised concerns about exposure to biocide aerosols in indoor environments. A sampler capable of accumulating PHMG from aqueous aerosols was developed as an alternative to low-volume air samplers. This sampler was prepared by placing glass beads coated with 2-(2,4,5,7-tetrabromo-6-oxido-3-oxo-3H-xanthen-9-yl)benzoate (Eosin Y) in a custom-made plastic holder. Passive sampling rates, measured in a bench-top exposure chamber at two different aqueous PHMG aerosol generation rates, were found to be independent of the experimental conditions. This suggests that the capacity of the sampler to accumulate the PHMG aerosol was sufficient for the sampling duration tested. However, the passive sampling rate was 7.6 × 10{sup −6} m{sup 3}/h for the sampler area of 22 cm{sup 2}. This rate is lower than the typical human breathing rate and inadequate for quantitative instrumental analyses at low concentrations in indoor air. A 30-fold enhancement of the sampling rate was achieved by forced convection using a commercial battery-operated fan at ≥2000 rpm. With this accelerated sampling rate, the sampler could be used to monitor time-integrated concentrations of PHMG aerosols in the air.

The Effect of UVC Irradiation on the Mechanical Properties of Chitosan Membrane in Sterilization Process

Science.gov (United States)

Rupiasih, N. N.; Sumadiyasa, M.; Putra, I. K.

2018-04-01

The present study, we report about the effect of UVC irradiation on the mechanical properties of chitosan membrane in the sterilization process. The membrane used was chitosan membrane 2% which prepared by a casting method using chitosan as matrix and acetic acid 1% as a solvent. The UVC source used was germicidal ultraviolet (UVG) which widely used for sterilization purposes. Variation doses were done by the varying time of irradiation, e.g. 5 min, 15 min, 30 min, and 60 min. Those samples are named as S1, S2, S3, and S4, respectively. Chitosan membrane before irradiation namely S0 also used for comparative study. The effect of UVC irradiation on the mechanical properties of membranes has been examined by different techniques including FTIR, DMA, and the water uptake capability. The results showed that ultimate tensile strength (UTS) and moduli of elasticity (E) were increased by increasing the irradiation time. From FTIR analysis obtained that no new molecules were formed in irradiated membranes. The water uptakes capability of the membranes after irradiation was smaller compared with before irradiation, and among the irradiated membranes, the water uptake capabilities were increased by increasing the exposure time. These observations suggested that more care should be taken during the sterilization process and outdoor used of the membrane. The other side, the UVC irradiation can improve the mechanical properties of the membranes.

Current Opinion and Controversies of Dialyser Reuse

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Brown Colin

2001-01-01

Full Text Available Reuse of dialysers has been an integral part of hemodialysis since its inception. Over the past decade, reuse has increased significantly in many countries, most notably in the United States, while vanishing entirely in some other countries, such as Portugal and France. In the United States, which is most widely used as an example because of the large amount of data available, the mortality of dialysis patients has steadily decreased even as reuse has increased. This improvement is probably the result of a complex of factors including understanding the role of comorbidity, treatment unit characteristics, barriers to adequate dialysis, nutrition, anemia, high flux dialysis and dialyser membrane improvements and the desired dialysis dose. Reuse provides a significant economic benefit that allows the use of more efficient and expensive larger biocompatible synthetic membranes to provide high-quality dialysis in the face of cost inflation, limited medical resources and fixed reimbursement. Rather than being legitimized by clinical practice alone, reprocessing, supported by clinical studies, allows the provision of superior treatment to more patients safely and economically. Recent reports concerning dialyser reprocessing have centered not only on morbidity and mortality, but also on questions of the specific effects of different germicides on various types of dialyser membranes (e.g., cellulosic, synthetic, high-flux, etc. and on the possible role of dialyser reprocessing in the transmission of hepatitis C.

Active site labeling of the guanine-7-methyltransferase

International Nuclear Information System (INIS)

Streaker, E.; Sitz, T.O.

1992-01-01

Studies on the guanine-7-methyltransferase have defined three domains in the active site: the S-adenosylmethionine (SAM) region, the cap region (GpppG), and the RNA binding domain (--NpNpNpNpNp---). The authors attempted to label the SAM binding domain by a photoaffinity label using 8-azido-SAM and another method using 3 H-SAM and long exposures to uv-light. Neither method was successful. The next approach was to attempt to label the cap-RNA binding domain (GpppGpNpNpNpNpN) by synthesizing RNA containing 8-azido-Ap using an in vitro transcription system and T7 RNA polymerase. The 8-azido-ATP inhibited the T7 RNA polymerase preventing the synthesis of RNA. As they were unable to synthesize the photoaffinity label, they next tried to synthesize an end labeled RNA and directly label by long exposures to uv-light. When the enzyme was incubated with 32 P-labeled RNA for 15 min at 37 degrees and then exposed to a germicidal lamp for various times at O degrees, optimal labeling occurred after 45 min. Various enzyme preparations were labeled by this method and two polypeptides were found to specifically bind the non-methylated mRNA analog. This labeling method should allow characterization of the subunit structure and generate information about the nature of the RNA binding domain

Numerical investigation of upper-room UVGI disinfection efficacy in an environmental chamber with a ceiling fan.

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Zhu, Shengwei; Srebric, Jelena; Rudnick, Stephen N; Vincent, Richard L; Nardell, Edward A

2013-01-01

This study investigated the disinfection efficacy of the upper-room ultraviolet germicidal irradiation (UR-UVGI) system with ceiling fans. The investigation used the steady-state computational fluid dynamics (CFD) simulations to solve the rotation of ceiling fan with a rotating reference frame. Two ambient air exchange rates, 2 and 6 air changes per hour (ACH), and four downward fan rotational speeds, 0, 80, 150 and 235 rpm were considered. In addition, the passive scalar concentration simulations incorporated ultraviolet (UV) dose by two methods: one based on the total exposure time and average UV fluence rate, and another based on SVE3* (New Scale for Ventilation Efficiency 3), originally defined to evaluate the mean age of the air from an air supply opening. Overall, the CFD results enabled the evaluation of UR-UVGI disinfection efficacy using different indices, including the fraction of remaining microorganisms, equivalent air exchange rate, UR-UVGI effectiveness and tuberculosis infection probability by the Wells-Riley equation. The results indicated that air exchange rate was the decisive factor for determining UR-UVGI performance in disinfecting indoor air. Using a ceiling fan could also improve the performance in general. Furthermore, the results clarified the mechanism for the ceiling fan to influence UR-UVGI disinfection efficacy. © 2013 The Authors Photochemistry and Photobiology © 2013 The American Society of Photobiology.

Towards a compatible probiotic-antibiotic combination therapy: assessment of antimicrobial resistance in the Japanese probiotics.

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Hammad, A M; Shimamoto, T

2010-10-01

To determine the antimicrobial resistance of the Japanese probiotics available in the market without a pharmacist's supervision. A total of 43 isolates were obtained from 40 samples of probiotics (30 dairy products and 10 products in tablet form). Isolates were identified using 16S rRNA gene sequencing and tested for their susceptibility to 14 antimicrobials. They were screened using PCR for some antibiotic resistance genes. Inactivation of cefepime, clarithromycin and vancomycin by different inocula of 11 strains was evaluated using the antibiotic inactivation bioassay. None of the dairy probiotics showed a level of constitutive resistance or carried inducible resistance genes, making them suitable to be administrated with macrolides. Among the probiotics in tablet form only Enterococcus faecium strains carrying the msrC gene showed an MIC(90) of 4 μg ml(-1). Extended-spectrum β-lactams, tetracyclines and ampicillin exhibited powerful germicidal activity against the vast majority of the probiotic strains. There is a limited choice of the Japanese probiotics that can be administered with clinically used antibiotics. Japanese probiotics are widely distributed all over the world. Through the findings of our study, we have attempted to provide guidance for clinicians interested in using the Japanese probiotics in combination with antibiotics. © 2010 The Authors. Journal compilation © 2010 The Society for Applied Microbiology.

The Effect of Photon Source on Heterogeneous Photocatalytic Oxidation of Ethanol by a Silica-Titania Composite

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Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.; Mazyck, David W.

2011-01-01

The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp ((gamma)max=365 nm) at its maximum light intensity or a UV-C germicidal lamp ((gamma)max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM/s) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO2 (mu)mol/photons). UV-C irradiation also led to decreased intermediate concentration in the effluent . compared to UV-A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.

Evaluation of the ophthalmic and dermal irritability of the OLEOMASAJE formulation

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Maritza F. Díaz

2015-08-01

Full Text Available Context: Ozonized vegetable oils present germicidal effects which can be used as active principle in different cosmetological compositions. The thematic about of the corporal massage advantage have been very treatment by aesthetics, dermatologic and consumers. OLEOMASAJE formulation content ozonized sunflower oil OLEOZON as active principle active which present moisturizer and conditioner effects. Aims: To determine the possible dermal and ophthalmic irritability effects of the OLEOMASAJE. Methods: The trial was conducted in rabbits and the techniques described in the standardized procedures of the work established by the Center of Biological Research and Evaluations from Pharmacy and Food Institute of Havana University were used according to Norma ISO 10993-10. The ethical principles of the Good Practices of Laboratory were fulfilled to avoid suffering to the animals during the experimentation. Male rabbits with body weight between 2.05 and 2.48 kg were used. In the skin and the ocular structures the effects were observed immediately after of the application at 1, 24, 48 and 72 hours. Draize´s scale was applied to evaluate skin and ocular structures lesions. Results: The OLEOMASAJE formulation does not irritate de skin of the assayed rabbits. However, the ocular structures irritability index was of 4.5 after of first hour to apply of product. These wounds were missing before of 24 hours to apply of product. Conclusions: The OLEOMASAJE formulation obeys the indispensable requirements for the acceptance as cosmetic product and for it is used in corporal massage.

Changes in buoyant density relationships of two cell types of Coxiella burneti phase I

International Nuclear Information System (INIS)

Wachter, R.F.; Briggs, G.P.; Gangemi, J.D.; Pedersen, C.E. Jr.

1975-01-01

Coxiella burneti phase I, purified from a formalin-inactivated yolk-sac vaccine, was separated into two bands of morphologically distinct cell types when subjected to sucrose gradient centrifugation. Recycling of the less dense, rod-shaped cells in unbuffered sucrose gradients (pH 5.5 to 6.0) resulted in the formation of bands having the location and appearance of the original two bands. Recycling of the denser band of larger ovoid-shaped cells yielded a single band, suggesting that the larger cell type arose from the smaller cell. In contrast to vaccine-derived rickettsiae, live, cell culture-propagated phase I organisms formed a single band in unbuffered sucrose gradients, at the same density as the upper band of the vaccine preparation. Centrifugation of cell culture-derived rickettsiae for 26 to 48 h in sucrose gradients of pH 5.5 resulted in the formation of a second band, at the same density as the lower band of the vaccine preparation. This did not occur in gradients of pH 7.0. Treatment of cell culture-propagated rickettsiae with formalin or germicidal ultraviolet radiation induced a total shift of the less dense cell population to a zone of higher density when centrifuged isopycnically in CsCl gradients. This density change did not occur in sucrose gradients, suggesting a difference in the effect of these treatments on the permeability of the cell membrane to sucrose and CsCl

Peritoneal dialysis in Asia.

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Cheng, I K

1996-01-01

The socioeconomic status of Asian countries is diverse, and government reimbursement policies for treatment of patients suffering from end-stage renal disease (ESRD) vary greatly from one country to another. Both of these factors have a major impact not only on the choice of treatment for ESRD but also on the utilization of peritoneal dialysis (PD) in this region. Based on the data collected from 11 representative Asian countries, several observations can be made. First, the treatment rates for ESRD in these countries correlated closely with their gross domestic product (GDP) per capita income. Second, the PD utilization rate appeared to have a biphasic relationship with the GDP per capita income and treatment rate, in that countries with the highest and the lowest treatment rates tended to have lower PD utilization rates, whereas countries with modest treatment rates tended to have higher PD utilization rates. The reason for low PD utilization in countries with the highest treatment rates differs from that in countries with low treatment rates. In the former, because of full government reimbursement, there is little physician incentive to introduce PD as an alternative form of ESRD treatment to in-center hemodialysis (HD), whereas in the latter, the complete lack of government reimbursement prevents the introduction of PD as a form of treatment. This pattern is likely to change in the future because, of the 11 countries surveyed, all except Thailand have recorded a growth rate which is higher for PD than HD over the last three years. The rate of utilization of different PD systems varies greatly among different Asian countries. Automated PD has yet to gain popularity in Asia. Conventional straight-line systems remain the dominant PD systems in use in Hong Kong, Korea, Thailand, and the Philippines, while in Malaysia and Singapore UV germicidal connection devices are most popular. However, in all these countries there has been a progressive shift over the last

An integrated study on antimicrobial activity and ecotoxicity of quantum dots and quantum dots coated with the antimicrobial peptide indolicidin

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Galdiero E

2016-08-01

Full Text Available Emilia Galdiero,1 Antonietta Siciliano,1 Valeria Maselli,1 Renato Gesuele,1 Marco Guida,1 Domenico Fulgione,1 Stefania Galdiero,2 Lucia Lombardi,3 Annarita Falanga2 1Department of Biology, University of Naples “Federico II”, Naples, Italy; 2Department of Pharmacy and Cirpeb, University of Naples “Federico II”, Naples, Italy; 3Department of Experimental Medicine, Second University of Naples, Naples, Italy Abstract: This study attempts to evaluate the antimicrobial activity and the ecotoxicity of quantum dots (QDs alone and coated with indolicidin. To meet this objective, we tested the level of antimicrobial activity on Gram-positive and Gram-negative bacteria, and we designed an ecotoxicological battery of test systems and indicators able to detect different effects using a variety of end points. The antibacterial activity was analyzed against Staphylococcus aureus (ATCC 6538, Pseudomonas aeruginosa (ATCC 1025, Escherichia coli (ATCC 11229, and Klebsiella pneumoniae (ATCC 10031, and the results showed an improved germicidal action of QDs-Ind. Toxicity studies on Daphnia magna indicated a decrease in toxicity for QDs-Ind compared to QDs alone, lack of bioluminescence inhibition on Vibrio fisheri, and no mutations in Salmonella typhimurium TA 100. The comet assay and oxidative stress experiments performed on D. magna showed a genotoxic and an oxidative damage with a dose–response trend. Indolicidin retained its activity when bound to QDs. We observed an enhanced activity for QDs-Ind. The presence of indolicidin on the surface of QDs was able to decrease its QDs toxicity. Keywords: peptide, quantum dots, ecotoxicity, antimicrobial activity, oxidative stress, genotoxicity

Airborne rhinovirus detection and effect of ultraviolet irradiation on detection by a semi-nested RT-PCR assay

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Rudnick Stephen

2003-01-01

Full Text Available Abstract Background Rhinovirus, the most common cause of upper respiratory tract infections, has been implicated in asthma exacerbations and possibly asthma deaths. Although the method of transmission of rhinoviruses is disputed, several studies have demonstrated that aerosol transmission is a likely method of transmission among adults. As a first step in studies of possible airborne rhinovirus transmission, we developed methods to detect aerosolized rhinovirus by extending existing technology for detecting infectious agents in nasal specimens. Methods We aerosolized rhinovirus in a small aerosol chamber. Experiments were conducted with decreasing concentrations of rhinovirus. To determine the effect of UV irradiation on detection of rhinoviral aerosols, we also conducted experiments in which we exposed aerosols to a UV dose of 684 mJ/m2. Aerosols were collected on Teflon filters and rhinovirus recovered in Qiagen AVL buffer using the Qiagen QIAamp Viral RNA Kit (Qiagen Corp., Valencia, California followed by semi-nested RT-PCR and detection by gel electrophoresis. Results We obtained positive results from filter samples that had collected at least 1.3 TCID50 of aerosolized rhinovirus. Ultraviolet irradiation of airborne virus at doses much greater than those used in upper-room UV germicidal irradiation applications did not inhibit subsequent detection with the RT-PCR assay. Conclusion The air sampling and extraction methodology developed in this study should be applicable to the detection of rhinovirus and other airborne viruses in the indoor air of offices and schools. This method, however, cannot distinguish UV inactivated virus from infectious viral particles.

Large-Scale Purification, Characterization, and Spore Outgrowth Inhibitory Effect of Thurincin H, a Bacteriocin Produced by Bacillus thuringiensis SF361.

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Wang, Gaoyan; Manns, David C; Guron, Giselle K; Churey, John J; Worobo, Randy W

2014-06-01

Large-scale purification of the highly hydrophobic bacteriocin thurincin H was accomplished via a novel and simple two-step method: ammonia sulfate precipitation and C18 solid-phase extraction. The inhibition spectrum and stability of thurincin H as well as its antagonistic activity against Bacillus cereus F4552 spores were further characterized. In the purification method, secreted proteins contained in the supernatant of a 40 h incubated culture of B. thuringiensis SF361 were precipitated by 68 % ammonia sulfate and purified by reverse-phase chromatography, with a yield of 18.53 mg/l of pure thurincin H. Silver-stained SDS-PAGE, high-performance liquid chromatography, and liquid chromatography-mass spectrometry confirmed the high purity of the prepared sample. Thurincin H exhibited a broad antimicrobial activity against 22 tested bacterial strains among six different genera including Bacillus, Carnobacterium, Geobacillus, Enterococcus, Listeria, and Staphylococcus. There was no detectable activity against any of the selected yeast or fungi. The bacteriocin activity was stable for 30 min at 50 °C and decreased to undetectable levels within 10 min at temperatures above 80 °C. Thurincin H is also stable from pH 2-7 for at least 24 h at room temperature. Thurincin H is germicidal against B. cereus spores in brain heart infusion broth, but not in Tris-NaCl buffer. The efficient purification method enables the large-scale production of pure thurincin H. The broad inhibitory spectrum of this bacteriocin may be of interest as a potential natural biopreservative in the food industry, particularly in post-processed and ready-to-eat food.

Therapeutic genes for anti-HIV/AIDS gene therapy.

Science.gov (United States)

Bovolenta, Chiara; Porcellini, Simona; Alberici, Luca

2013-01-01

The multiple therapeutic approaches developed so far to cope HIV-1 infection, such as anti-retroviral drugs, germicides and several attempts of therapeutic vaccination have provided significant amelioration in terms of life-quality and survival rate of AIDS patients. Nevertheless, no approach has demonstrated efficacy in eradicating this lethal, if untreated, infection. The curative power of gene therapy has been proven for the treatment of monogenic immunodeficiensies, where permanent gene modification of host cells is sufficient to correct the defect for life-time. No doubt, a similar concept is not applicable for gene therapy of infectious immunodeficiensies as AIDS, where there is not a single gene to be corrected; rather engineered cells must gain immunotherapeutic or antiviral features to grant either short- or long-term efficacy mostly by acquisition of antiviral genes or payloads. Anti-HIV/AIDS gene therapy is one of the most promising strategy, although challenging, to eradicate HIV-1 infection. In fact, genetic modification of hematopoietic stem cells with one or multiple therapeutic genes is expected to originate blood cell progenies resistant to viral infection and thereby able to prevail on infected unprotected cells. Ultimately, protected cells will re-establish a functional immune system able to control HIV-1 replication. More than hundred gene therapy clinical trials against AIDS employing different viral vectors and transgenes have been approved or are currently ongoing worldwide. This review will overview anti-HIV-1 infection gene therapy field evaluating strength and weakness of the transgenes and payloads used in the past and of those potentially exploitable in the future.

Foodborne Pread of Hepatitis A: Recent Studies on Virus Survival, Transfer and Inactivation

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Syed A Sattar

2000-01-01

Full Text Available Hepatitis A virus (HAV is responsible for considerable morbidity and economic losses worldwide, and is the only reportable, foodborne viral pathogen in Canada. Outbreaks caused by it occur more frequently in settings such as hospitals, daycare centres, schools, and in association with foods and food service establishments. In recent years, the incidence of hepatitis A has increased in Canada. Many factors, including changing lifestyles and demographics, faster and more frequent travel, and enhanced importation of foods from hepatitis A-endemic regions, may be behind this increase. Despite its increasing significance as a human pathogen, not much was known until recently about the survival and inactivation of HAV, and even less was understood about the effectiveness of measures to prevent and control its foodborne spread. Studies conducted in the past decade have shown that HAV can survive for several hours on human hands and for several days on environmental surfaces indoors. The virus can also retain its infectivity for several days on fruits and vegetables which are often consumed raw, and such imported items have already been incriminated in disease outbreaks. Casual contact between contaminated hands and clean food items can readily lead to a transfer of as much as 10% of the infectious virus. HAV is also relatively resistant to inactivation by heat, gamma irradiation and chemical germicides. In view of these findings, better approaches to prevent the contamination of foods with HAV and more effective methods for its inactivation in foods, on environmental surfaces and on the hands of food handlers are needed.

Microbiological evaluation of anatomical organs submitted to glycerinization and freeze-drying techniques

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Marianna Justo

2016-06-01

Full Text Available Alternatives conservation techniques are being requested with the proposal of formaldehyde substitution. Formaldehyde results in excessive anatomical specimens' weight and it can cause serious health problems to the manipulator, such as cancer. However, it provides an efficient germicide and fungicide action depending on concentration. The substitute techniques are glicerinization and freeze-drying which have advantages such as non-production of smells, lightness of the organs and dispenses the use of fixatives in conservation. As well as both intrinsic and extrinsic factors interfere in microbial growth, microbiological analyzes are essential to detect possible deteriorative microorganisms in organs and concluding effectively the technique used. Formalinized, glycerinated and freeze-drying organs were collected in three different times which were intercalated by two months, except formalinization that had one evaluation. The procedure required the use of sterilized swabs wetted in peptone water and molds measuring 5,0 cm x 10,0 cm positioned on two different piece's local resulting in 100 cm2 of area, to spread plate of total moulds, mesophiles (except in freeze-drying, psychrophilic (only in freeze-drying and Pseudomonas sp (except in formalinization. All the plates were counted and compared between each technique's evaluations by variance analyzes. Both alternatives techniques resulted in zero or in very low microbial quantity to cause health problems as well as it preserve pieces morphology. All values of all analyzes resulted below 1/ml, showing that glicerinization and freeze-drying techniques are so as efficient as formaldehyde. Keywords: Organs conservation, Anatomical techniques, Microbiology, Microbial growth

Recovery from a near-lethal exposure to ultraviolet-C radiation in a scleractinian coral.

Science.gov (United States)

Basti, David; Bricknell, Ian; Beane, Dawna; Bouchard, Deborah

2009-04-01

Hermatypic (reef building) corals live in an environment characterized by high ambient levels of photosynthetically active radiation (PAR) and ultraviolet radiation (UVR). Photoadaptive mechanisms have evolved to protect the sensitive cell structures of the host coral and their photosynthetic, endosymbiotic zooxanthellae. Environmental stressors may destabilize the coral-zooxanthellae system resulting in the expulsion of zooxanthellae and/or loss of photosynthetic pigment within zooxanthellae, causing a condition known as bleaching. It is estimated that 1% of the world's coral population is lost yearly, partly due to bleaching. Despite intensive research efforts, a single unified mechanism cannot explain this phenomenon. Although UVA and UVB cellular damage is well documented, UVC damage is rarely reported due to its almost complete absorption in the stratosphere. A small scale coral propagation system at the University of Maine was accidentally exposed to 15.5h of UVC radiation (253.7 nm) from a G15T8 germicidal lamp, resulting in a cumulative surface irradiance of 8.39 x 10(4) J m(-2). An experiment was designed to monitor the progression of UVC induced damage. Branch sections from affected scleractinian corals, Acropora yongei and Acropora formosa were submitted to histopathology to provide an historical record of tissue response. The death of gastrodermal cells and necrosis resulted in the release of intracellular zooxanthellae into the gastrovascular canals. Zooxanthellae were also injured as evidenced by pale coloration, increased vacuolization and loss of membrane integrity. The recovery of damaged coral tissue likely proceeds by re-epithelialization and zooxanthellae repopulation of gastrodermal cells by adjacent healthy tissue.

Unexpected photoreactivation of Vibrio harveyi bacteria living in ionization environment

International Nuclear Information System (INIS)

Alifano, P.; Tala, A.; Tredici, S. M.; Nassisi, V.; Siciliano, M. V.

2011-01-01

Bacteria undergoing environmental effects is extremely interesting for structural, mechanistic, and evolutionary implications. Luminescent bacteria that have evolved in a specific ambient have developed particular responses and their behavior can give us new suggestions on the task and production of luciferina proteins. To analyze the UV interaction under controlled laboratory conditions, we used photoluminescent bacterial strains belonging to a new species evolutionarily close to Vibrio harveyi sampled from a coastal cave with a high radon content that generates ionizing radiation. The survival of the bacterial strains was analyzed, in the light and in the dark, following a variety of genotoxic treatments including UV radiation exposure. The strains were irradiated by a germicide lamp. The results demonstrated that most of the strains exhibited a low rate of survival after the UV exposure. After irradiation by visible light following the UV exposure, all strains showed a high capability of photoreactivation when grown. This capability was quite unexpected because these bacteria were sampled from a dark ambient without UV radiation. This leads us to hypothesize that the photoreactivation in these bacteria might have been evolved to repair DNA lesions also induced by different radiation sources other than UV (e.g., x-ray) and that the luminescent bacteria might use their own light emission to carry out the photoreactivation. The high capability of photoreactivation of these bacteria was also justified by the results of deconvolution. The deconvolution was applied to the emission spectra and it was able to show evidence of different light peaks. The presence of the visible peak could control the photolysis enzyme.

Photobiological activity of furazolidone

International Nuclear Information System (INIS)

Chatterjee, S.N.; Chanda, P.K.

1976-01-01

Furazolidone, a synthetic nitrofuran, is used in the treatment of cholera and other diseases. The photobiological activity of this drug has been investigated using Vibrio cholerae OGAWA 154 and the cholera phage PL 163/10. The phage suspension was exposed to a fluorescent daylight lamp for photodynamic studies and to a germicidal lamp for U.V.-inactivation studies. When the phage was exposed to U.V. light in the presence of furazolidone, the rate of inactivation was found to decrease with increasing concentrations of the drug, and the inactivation followed first-order reaction kinetics. The drug thus afforded pH-dependent protection for the target of U.V.-light, which was most probably the phage DNA. For any drug concentration a constant dose-reduction factor irrespective of the survival level was obtained. White light, in contrast to U.V., caused an increase in the rate of inactivation with increasing drug concentrations. Kinetic studies of this photodynamic action gave values of 8.88 x 10 -5 M (in phosphate buffered saline pH 7.0), and 3.97 x 10 -5 M (in 5 mM tris-HCl buffer pH 7.4), for the dissociation constant (Ksub(a)) of furazolidone phage complex. Varying times of pre-incubation with furazolidone before irradiation demonstrated that less than 5 minutes was required for the saturation of the target with the drug, indicating that the protein coat of the phage is highly permeable to the drug. Furazolidone therefore exhibits both a photodynamic action under visible light and a photoprotective action under U.V.-light. (U.K.)

Comparative SEM analysis of nine F22 aligner cleaning strategies

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Luca Lombardo

2017-09-01

Full Text Available Abstract Background The orthodontics industry has paid great attention to the aesthetics of orthodontic appliances, seeking to make them as invisible as possible. There are several advantages to clear aligner systems, including aesthetics, comfort, chairside time reduction, and the fact that they can be removed for meals and oral hygiene procedures. Methods Five patients were each given a series of F22 aligners, each to be worn for 14 days and nights, with the exception of meal and brushing times. Patients were instructed to clean each aligner using a prescribed strategy, and sections of the used aligners were observed under SEM. One grey-scale SEM image was saved per aligner in JPEG format with an 8-bit colour depth, and a total of 45 measurements on the grey scale (“Value” variable were made. This dataset was analysed statistically via repeated measures ANOVA to determine the effect of each of the nine cleaning strategies in each of the five patients. Results A statistically significant difference in the efficacy of the cleaning strategies was detected. Specifically, rinsing with water alone was significantly less efficacious, and a combination of cationic detergent solution and ultrasonication was significantly more efficacious than the other methods (p < 0.05. Conclusions Of the nine cleaning strategies examined, only that involving 5 min of ultrasonication at 42 k Hz combined with a 0.3% germicidal cationic detergent was observed to be statistically effective at removing the bacterial biofilm from the surface of F22 aligners.

Inactivation of natural enteric bacteria in real municipal wastewater by solar photo-Fenton at neutral pH.

Science.gov (United States)

Ortega-Gómez, E; Esteban García, B; Ballesteros Martín, M M; Fernández Ibáñez, P; Sánchez Pérez, J A

2014-10-15

This study analyses the use of the solar photo-Fenton treatment in compound parabolic collector photo-reactors at neutral pH for the inactivation of wild enteric Escherichia coli and total coliform present in secondary effluents of a municipal wastewater treatment plant (SEWWTP). Control experiments were carried out to find out the individual effects of mechanical stress, pH, reactants concentration, and UVA radiation as well as the combined effects of UVA-Fe and UVA-H2O2. The synergistic germicidal effect of solar-UVA with 50 mg L(-1) of H2O2 led to complete disinfection (up to the detection limit) of total coliforms within 120 min. The disinfection process was accelerated by photo-Fenton, achieving total inactivation in 60 min reducing natural bicarbonate concentration found in the SEWWTP from 250 to 100 mg L(-1) did not give rise to a significant enhancement in bacterial inactivation. Additionally, the effect of hydrogen peroxide and iron dosage was evaluated. The best conditions were 50 mg L(-1) of H2O2 and 20 mg L(-1) of Fe(2+). Due to the variability of the SEWWTP during autumn and winter seasons, the inactivation kinetic constant varied between 0.07 ± 0.04 and 0.17 ± 0.04 min(-1). Moreover, the water treated by solar photo-Fenton fulfilled the microbiological quality requirement for wastewater reuse in irrigation as per the WHO guidelines and in particular for Spanish legislation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of ultraviolet radiation on saccharomyces uvarum metabolism

International Nuclear Information System (INIS)

Luciano, J.Z.; Hix, C.

1987-01-01

The objective of this study was to measure the effect of UV radiation on the metabolism of Saccharomcyes uvarum in wort used in beer production. Pure yeast cultures were exposed to a Westinghouse G8T5 germicidal lamp for 10, 20, 30 and 40 minutes and added to fresh wort. The cultures were allowed to ferment for 96 hours at 130 C and fermentation products were assayed at 24 hour intervals and analyzed on a SCABA BEER ANALYZER. Metabolic parameters measured were balling, alcohol and cell count. Percent alcohol (V/V %) increased significantly at all exposures, but as the UV dosage increased, alcohol levels showed a significant decline with longer exposures. The assimilation of sugars or balling levels dropped at each exposure level among samples. The ability for the yeast to assimilate sugars decreased as UV exposure was increased although pitching rates fluctuated. (Pitching rates are the cell count readings at inoculation). None of the samples showed a logarithmic growth pattern, except for the controls which did not exhibit a lag phase. All other samples decreased cell counts as exposure levels increased, without peaks. Substrate availability was not a factor in the metabolism of Saccharomyces uvarum. Cell count levels at each exposure could have possibly affected the metabolic parameters because of excessive cell killing. Viabilities at the exposure levels studied show that the number of live cells available for nutrient uptake was lower at each level. However, the peak levels of the parameters measured were very close to the controls. Although the availability of cells was low, metabolic rates could have been altered by the UV light

Effect of ultraviolet-C light on postharvest decay of strawberry

International Nuclear Information System (INIS)

Nigro, F.; Ippolito, A.; Salerno, M.; Lattanzio, V.

2000-01-01

The effect of ultraviolet-C light (u.v.-C) at low doses on postharvest decay of strawberries caused by Botrytis cinerea and other pathogens was investigated. Phenylalanine ammonia-lyase (PAL) activity and ethylene production, as influenced by ultraviolet-C irradiation, were also determined. Strawberries (cv. ‘Pajaro’) from plants that had been treated with chemicals against grey mould were irradiated with u.v.-C doses ranging from 0.25 to 4.00 kJ m-2 and inoculated with B. cinerea at different times (0, 12, 24 and 48 hours) after irradiation. To assess the effect of u.v.-C light on the naturally occurring postharvest decay, organically grown strawberries were also used. After treatment the strawberries were stored at 20±1°C or at 3°C. u.v.-C doses at 0.50 and 1.00 kJ m-2 significantly reduced botrytis storage rot arising from both artificial inoculations and natural infections in comparison with the unirradiated control. The doses shown to reduce botrytis rot produced an increase in PAL activity 12 h after irradiation; this result indicates the activation of metabolic a pathway related to the biosynthesis of phenolic compounds, which are usually characterized by antifungal activity. In addition, u.v.-C irradiation caused an increase in ethylene production proportional to the doses applied, reaching the highest value 6 h after treatment. The overall results from these investigations indicate that treatment with low u.v.-C doses produces a reduction in postharvest decay of strawberries related to induced resistance mechanisms. Moreover, a germicidal effect of reducing external contaminating pathogens cannot be excluded

Distribution and elimination of Norfloxacin in Fenneropenaeus chinensis larvae

Science.gov (United States)

Sun, Ming; Li, Jian; Zhao, Fazhen; Li, Jitao; Chang, Zhiqiang

2013-09-01

This study examined the distribution and elimination of Norfloxacin (NFLX) in Fenneropenaeus chinensis ovary and egg and newly hatched larvae. Mature parental shrimp were exposed to 4 or 10 mg L-1 NFLX for 2 or 5 d. Ovary and eggs of the shrimp were sampled after spawning in order to detect NFLX residue using high-performance liquid chromatography (HPLC). Results showed that NFLX residue accumulated in F. chinensis eggs after the parental exposure, with the highest residue detected in ovary. To examine the fate of NFLX residue in larvae, we further determined the concentration of NFLX residue in F. chinensis eggs and larvae at 4 different developmental stages after 24-h exposure. From the newly metamorphosed larvae (0 h post-metamorphosis, h.p.m), samples were taken at different time intervals to 72 h.p.m. HPLC assay showed that the concentrations of NFLX residue in zoea exposed to 4 and 10 mg L-1 NFLX were the highest at 1.5 h, i.e., 0.332 and 0.454 μg g-1, respectively. At the two NFLX exposure levels, the elimination time of half NFLX (half life) in nauplius was 45.36 and 49.85 h, respectively, followed by that in zoea (31.68 and 33.13 h), mysis larvae (42.24 and 47.28 h) and postlarvae (24.48 and 30.96 h). Both NFLX exposure levels had a germicidal effect. The distribution and elimination of NFLX residue in F. chinensis tissue, eggs and larvae correlated well with the drug exposure level. The disappearance of NFLX residue coincided with the larval growth, and the half-life of NFLX decreased with the larval development.

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

International Nuclear Information System (INIS)

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

2012-01-01

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: ► A thorough review of current state of play of solar water disinfection. ► An examination of both laboratory and field studies. ► 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.

Influence of silver on photocatalytic activity of TiO2

International Nuclear Information System (INIS)

Kisen, Carla Yuri; Teodoro, Vinicius; Zaghete, Maria Ap.; Perazolli, Leinig Antonio; Longo, Elson

2016-01-01

Full text: This work studied the influence of silver on photo activity of TiO 2 , prepared by Pechini method, in the photodegradation of Rhodamine-B. The catalysts were prepared with different percentage of silver (0.0, 0.5 and 1.0 %) and different calcination temperatures (500, 600 and 700°C), characterized by X-ray diffraction (DRX) and field emission gun - scanning electron microscopy (FEG-SEM), The powders' photo catalytic activity was defined by Rhodamine-B decolorisation test. The solution containing the dye and the catalyst, in the concentration of 0,01 mmol L -1 e 1,0 g L -1 respectively, were submitted to radiation with 9W germicidal lamp for 120 minutes. The control samples, for comparison effects, were made with TiO 2 anatase (Synth brand) and photolysis tests. In the micrographs, obtained by SEM, all the temperatures and compositions employed presented similar morphologies, it is assumed the calcination temperature rise leads to a decreased apparent porosity and the generation of particles clusters. The X-ray diffractograms indicates the calcination temperature influence in the generation of distinct TiO 2 phases during the catalysts synthesis. Regardless of the TiO 2 proportions, the only actual phase with 500°C calcination is the anatase. At 600°C, the rutile phase coexisting with the anatase phase disappears, and the rutile phase predominates. Among the catalysts, what presented greater activity was the TiO 2 with 0.5% Ag and calcination temperature of 500°C, which degraded around 100% in 60 minutes. References: [1] P. Cozolli, E. Fanizza and A. Agostiano. J. Phys.Chem. B108, 9623-9630, 2004. (author)

Monitoring and control of UV and UV-TiO2 disinfections for municipal wastewater reclamation using artificial neural networks

International Nuclear Information System (INIS)

Lin, Chuang-Hung; Yu, Ruey-Fang; Cheng, Wen-Po; Liu, Chun-Ru

2012-01-01

Highlights: ► ANN models can effectively control both UV and UV-TiO 2 disinfections for wastewater reuse. ► Comparing to UV disinfection, UV-TiO 2 disinfection can save 13.2–15.7% of UV dosage and capacity. ► SS decreases disinfection efficiency when UV doses were 2 . - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO 2 can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO 2 disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO 2 disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO 2 disinfections. A novel ANN control strategy is applied to control UV and UV-TiO 2 disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO 2 disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO 2 disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2–15.7%.

Second-order advantage with excitation-emission photoinduced fluorimetry for the determination of the antiepileptic carbamazepine in environmental waters.

Science.gov (United States)

Lozano, Valeria A; Escandar, Graciela M

2013-06-11

A photochemically induced fluorescence system combined with second-order chemometric analysis for the determination of the anticonvulsant carbamazepine (CBZ) is presented. CBZ is a widely used drug for the treatment of epilepsy and is included in the group of emerging contaminant present in the aquatic environment. CBZ is not fluorescent in solution but can be converted into a fluorescent compound through a photochemical reaction in a strong acid medium. The determination is carried out by measuring excitation-emission photoinduced fluorescence matrices of the products formed upon ultraviolet light irradiation in a laboratory-constructed reactor constituted by two simple 4 W germicidal tubes. Working conditions related to both the reaction medium and the photoreactor geometry are optimized by an experimental design. The developed approach enabled the determination of CBZ at trace levels without the necessity of applying separation steps, and in the presence of uncalibrated interferences which also display photoinduced fluorescence and may be potentially present in the investigated samples. Different second-order algorithms were tested and successful resolution was achieved using multivariate curve resolution-alternating least-squares (MCR-ALS). The study is employed for the discussion of the scopes and yields of each of the applied second-order chemometric tools. The quality of the proposed method is probed through the determination of the studied emerging pollutant in both environmental and drinking water samples. After a pre-concentration step on a C18 membrane using 50.0 mL of real water samples, a prediction relative error of 2% and limits of detection and quantification of 0.2 and 0.6 ng mL(-1) were respectively obtained. Copyright © 2013 Elsevier B.V. All rights reserved.

Can biowarfare agents be defeated with light?

Science.gov (United States)

Vatansever, Fatma; Ferraresi, Cleber; de Sousa, Marcelo Victor Pires; Yin, Rui; Rineh, Ardeshir; Sharma, Sulbha K; Hamblin, Michael R

2013-01-01

Biological warfare and bioterrorism is an unpleasant fact of 21st century life. Highly infectious and profoundly virulent diseases may be caused in combat personnel or in civilian populations by the appropriate dissemination of viruses, bacteria, spores, fungi, or toxins. Dissemination may be airborne, waterborne, or by contamination of food or surfaces. Countermeasures may be directed toward destroying or neutralizing the agents outside the body before infection has taken place, by destroying the agents once they have entered the body before the disease has fully developed, or by immunizing susceptible populations against the effects. A range of light-based technologies may have a role to play in biodefense countermeasures. Germicidal UV (UVC) is exceptionally active in destroying a wide range of viruses and microbial cells, and recent data suggests that UVC has high selectivity over host mammalian cells and tissues. Two UVA mediated approaches may also have roles to play; one where UVA is combined with titanium dioxide nanoparticles in a process called photocatalysis, and a second where UVA is combined with psoralens (PUVA) to produce “killed but metabolically active” microbial cells that may be particularly suitable for vaccines. Many microbial cells are surprisingly sensitive to blue light alone, and blue light can effectively destroy bacteria, fungi, and Bacillus spores and can treat wound infections. The combination of photosensitizing dyes such as porphyrins or phenothiaziniums and red light is called photodynamic therapy (PDT) or photoinactivation, and this approach cannot only kill bacteria, spores, and fungi, but also inactivate viruses and toxins. Many reports have highlighted the ability of PDT to treat infections and stimulate the host immune system. Finally pulsed (femtosecond) high power lasers have been used to inactivate pathogens with some degree of selectivity. We have pointed to some of the ways light-based technology may be used to defeat

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.

Disinfection of Spacecraft Potable Water Systems by Photocatalytic Oxidation Using UV-A Light Emitting Diodes

Science.gov (United States)

Birmele, Michele N.; O'Neal, Jeremy A.; Roberts, Michael S.

2011-01-01

Ultraviolet (UV) light has long been used in terrestrial water treatment systems for photodisinfection and the removal of organic compounds by several processes including photoadsorption, photolysis, and photocatalytic oxidation/reduction. Despite its effectiveness for water treatment, UV has not been explored for spacecraft applications because of concerns about the safety and reliability of mercury-containing UV lamps. However, recent advances in ultraviolet light emitting diodes (UV LEDs) have enabled the utilization of nanomaterials that possess the appropriate optical properties for the manufacture of LEDs capable of producing monochromatic light at germicidal wavelengths. This report describes the testing of a commercial-off-the-shelf, high power Nichia UV-A LED (250mW A365nnJ for the excitation of titanium dioxide as a point-of-use (POD) disinfection device in a potable water system. The combination of an immobilized, high surface area photocatalyst with a UV-A LED is promising for potable water system disinfection since toxic chemicals and resupply requirements are reduced. No additional consumables like chemical biocides, absorption columns, or filters are required to disinfect and/or remove potentially toxic disinfectants from the potable water prior to use. Experiments were conducted in a static test stand consisting of a polypropylene microtiter plate containing 3mm glass balls coated with titanium dioxide. Wells filled with water were exposed to ultraviolet light from an actively-cooled UV-A LED positioned above each well and inoculated with six individual challenge microorganisms recovered from the International Space Station (ISS): Burkholderia cepacia, Cupriavidus metallidurans, Methylobacterium fujisawaense, Pseudomonas aeruginosa, Sphingomonas paucimobilis and Wautersia basilensis. Exposure to the Nichia UV-A LED with photocatalytic oxidation resulted in a complete (>7-log) reduction of each challenge bacteria population in UV-A LEDs and semi

Inactivation of bacterial spores by combination processes: ultraviolet plus gamma radiation. [Streptococcus faecium, micrococcus radiodurans, clostridium botulinum

Energy Technology Data Exchange (ETDEWEB)

Grecz, N; Durban, E

1973-01-01

Bacterial spores, viruses and some vegetative bacteria such as Streptococcus faecium and Micrococcus radiodurans are distinguished by high radiation resistance. In order to lay a theoretical basis for biomedical sterilization applications, we have investigated the combined action of uv and gamma rays. Spores of two strains of C. botulinum were selected, a highly radiation resistant strain, 33A having a D/sub 10/-value of 0.32 Mrad, and a relatively radiation sensitive strain, 51B having a D/sub 10/-value of 0.12 Mrad. Strain 33A exhibits an extensive initial ''shoulder'' in its uv as well as gamma ray survival curves; strain 51B shows only a slight shoulder. The shoulder in the gamma ray survival curve of spores of strain 33A could be reduced or completely eliminated by preirradiation with uv. Simultaneously the D/sub 10/-value for gamma inactivation of spores of 33A was reduced substantially. For example, the gamma resistance was reduced almost to half of its original D/sub 10/-value by uv-preirradiation for only one minute under an 8 watt GE germicidal lamp. The effect of uv-preirradiation on the radiation sensitive strain 51B was less pronounced. In fact, there was about seven fold higher positive interaction (synergism) between uv and gamma radiation in 33A spores than in 51B spores. The experiments suggest that interference with DNA repair enzymes in the radiation resistant strain are responsible for lethal synergism between uv and gamma radiation. A hypothesis is developed attempting to explain the combined effect of these two radiations in terms of a special summation of known DNA lesions in the cell. These observations emphasize the potential practical advantages of combining uv and gamma rays for effective sterilization of certain biomedical devices, drugs and biologicals.

Second-order advantage with excitation–emission photoinduced fluorimetry for the determination of the antiepileptic carbamazepine in environmental waters

International Nuclear Information System (INIS)

Lozano, Valeria A.; Escandar, Graciela M.

2013-01-01

Graphical abstract: -- Highlights: •A simple and safe method for the emerging contaminant carbamazepine is developed. •MCR-ALS algorithm allows us the quantification in very interfering media. •Determination is accomplished in natural waters using green-chemistry principles. -- Abstract: A photochemically induced fluorescence system combined with second-order chemometric analysis for the determination of the anticonvulsant carbamazepine (CBZ) is presented. CBZ is a widely used drug for the treatment of epilepsy and is included in the group of emerging contaminant present in the aquatic environment. CBZ is not fluorescent in solution but can be converted into a fluorescent compound through a photochemical reaction in a strong acid medium. The determination is carried out by measuring excitation–emission photoinduced fluorescence matrices of the products formed upon ultraviolet light irradiation in a laboratory-constructed reactor constituted by two simple 4 W germicidal tubes. Working conditions related to both the reaction medium and the photoreactor geometry are optimized by an experimental design. The developed approach enabled the determination of CBZ at trace levels without the necessity of applying separation steps, and in the presence of uncalibrated interferences which also display photoinduced fluorescence and may be potentially present in the investigated samples. Different second-order algorithms were tested and successful resolution was achieved using multivariate curve resolution-alternating least-squares (MCR-ALS). The study is employed for the discussion of the scopes and yields of each of the applied second-order chemometric tools. The quality of the proposed method is probed through the determination of the studied emerging pollutant in both environmental and drinking water samples. After a pre-concentration step on a C18 membrane using 50.0 mL of real water samples, a prediction relative error of 2% and limits of detection and

Induction of highly immunogenic variants of Lewis lung carcinoma tumor by ultraviolet irradiation

International Nuclear Information System (INIS)

Peppoloni, S.; Herberman, R.B.; Gorelik, E.

1985-01-01

This study was undertaken to determine whether in vitro treatment of Lewis lung carcinoma (3LL) cells with ultraviolet (UV) radiation could increase their immunogenicity. Tumor cells were irradiated with UV light from a germicidal lamp (254 nm; UV-C) at a dose of 720 J/sq m. After 2 weeks of culture, the surviving cell population was cloned by limiting dilution. Cell suspensions of each clone were injected intrafootpad in C57BL/6 mice at a dose of 2.5 X 10(5) cells per mouse. Eighty independent clones were tested. Fifty-one clones showed decreased tumorigenicity and failed to grow in 20 to 95% of immunocompetent mice, whereas they produced tumors in 100% of irradiated (550 R) and athymic nude mice. These clones were designated tum- (nontumorigenic) clones. In contrast, all 25 clones selected from the untreated parental 3LL induced progressively growing tumors in 100% of the mice. After two courses of UV treatment, the uncloned 3LL population was rejected in 45% of inoculated mice. Mice rejecting an inoculum of a tum- clone were completely resistant to subsequent challenge with higher doses of the same or unrelated tum- clones. This resistance was fully expressed even after irradiation of immune mice with 550 R. Mice immune to a tum- clone also were able to prevent the growth of various tum+ clones or untreated 3LL tumor cells. When tum- and tum+ clone cells were simultaneously inoculated intrafootpad in opposite legs, rejection of tum- clone resulted also in the prevention of the growth of tum+ clone. Spleen cells of immune mice caused rapid elimination of radiolabeled 3LL tumor cells from the place of their inoculation (intrafootpad) and prevented tumor growth

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%.

Monitoring and control of UV and UV-TiO{sub 2} disinfections for municipal wastewater reclamation using artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Lin, Chuang-Hung [Department of Architecture, National United University, Miao-Li 360, Taiwan, ROC (China); Yu, Ruey-Fang, E-mail: rfyu@nuu.edu.tw [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China); Cheng, Wen-Po; Liu, Chun-Ru [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan, ROC (China)

2012-03-30

Highlights: Black-Right-Pointing-Pointer ANN models can effectively control both UV and UV-TiO{sub 2} disinfections for wastewater reuse. Black-Right-Pointing-Pointer Comparing to UV disinfection, UV-TiO{sub 2} disinfection can save 13.2-15.7% of UV dosage and capacity. Black-Right-Pointing-Pointer SS decreases disinfection efficiency when UV doses were <10,000 {mu}W s/cm{sup 2}. - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO{sub 2} can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO{sub 2} disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO{sub 2} disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO{sub 2} disinfections. A novel ANN control strategy is applied to control UV and UV-TiO{sub 2} disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO{sub 2} disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO{sub 2} disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2-15.7%.

Second-order advantage with excitation–emission photoinduced fluorimetry for the determination of the antiepileptic carbamazepine in environmental waters

Energy Technology Data Exchange (ETDEWEB)

Lozano, Valeria A.; Escandar, Graciela M., E-mail: escandar@iquir-conicet.gov.ar

2013-06-11

Graphical abstract: -- Highlights: •A simple and safe method for the emerging contaminant carbamazepine is developed. •MCR-ALS algorithm allows us the quantification in very interfering media. •Determination is accomplished in natural waters using green-chemistry principles. -- Abstract: A photochemically induced fluorescence system combined with second-order chemometric analysis for the determination of the anticonvulsant carbamazepine (CBZ) is presented. CBZ is a widely used drug for the treatment of epilepsy and is included in the group of emerging contaminant present in the aquatic environment. CBZ is not fluorescent in solution but can be converted into a fluorescent compound through a photochemical reaction in a strong acid medium. The determination is carried out by measuring excitation–emission photoinduced fluorescence matrices of the products formed upon ultraviolet light irradiation in a laboratory-constructed reactor constituted by two simple 4 W germicidal tubes. Working conditions related to both the reaction medium and the photoreactor geometry are optimized by an experimental design. The developed approach enabled the determination of CBZ at trace levels without the necessity of applying separation steps, and in the presence of uncalibrated interferences which also display photoinduced fluorescence and may be potentially present in the investigated samples. Different second-order algorithms were tested and successful resolution was achieved using multivariate curve resolution-alternating least-squares (MCR-ALS). The study is employed for the discussion of the scopes and yields of each of the applied second-order chemometric tools. The quality of the proposed method is probed through the determination of the studied emerging pollutant in both environmental and drinking water samples. After a pre-concentration step on a C18 membrane using 50.0 mL of real water samples, a prediction relative error of 2% and limits of detection and

INVESTIGATION OF BACTERIOSTATIC PROPERTIES OF CHLORINATED COMPOUNDS FOR BEET-SUGAR INDUSTRY

Directory of Open Access Journals (Sweden)

N. G. Kulneva

2014-01-01

Full Text Available Summary. One of the major causes of decline in the quality of granulated sugar is bacterial contamination of sugar beet. This is due to the fact that the beet-sugar industry is a good object for the development of different groups of microorganisms. The main sources of infection of products of sugar manufacture can be soil, water, air, packaging, packaging materials, vehicles, clothing, equipment. The higher the beet contamination with the microorganisms, the more they decompose sucrose and secrete metabolic byproducts. In this regard, there is a need to reduce the negative impact of various groups of microorganisms and to minimize the loss of sucrose from decomposition. In accordance with the problem given the studies to determine the bacteriostatic properties of chlorinated compounds for sugar production were carried out. We used the cultivated fluid colonized with a pure culture of Leuconostoc mesenteroides and reagent treated as an object of study. In the experiments, we determined the accumulation of biomass of L. mesenteroides with nephelometric method by measuring the optical density of bacterial suspension. It was found out that after 24 hours of bacterial culturing the level of optical density in the control and active acidity were considerably higher compared with the sample treated with germicide. The number of microorganisms in the nutrient medium was determined by Vinogradsky-Shulgina-Brid’s. According to the study in the control is 1,7*10^16, in experiment with the introduction of the chlorinated compound it is 5,8*10^14. The experimental results show that the investigated chlorinated compound has bacteriostatic action against grampositive cocci saprophytic of L. mesenteroides and can be recommended for use in a sugar beet production.

On the Stability of Deinoxanthin Exposed to Mars Conditions during a Long-Term Space Mission and Implications for Biomarker Detection on Other Planets

Directory of Open Access Journals (Sweden)

Stefan Leuko

2017-09-01

Full Text Available Outer space, the final frontier, is a hostile and unforgiving place for any form of life as we know it. The unique environment of space allows for a close simulation of Mars surface conditions that cannot be simulated as accurately on the Earth. For this experiment, we tested the resistance of Deinococcus radiodurans to survive exposure to simulated Mars-like conditions in low-Earth orbit for a prolonged period of time as part of the Biology and Mars experiment (BIOMEX project. Special focus was placed on the integrity of the carotenoid deinoxanthin, which may serve as a potential biomarker to search for remnants of life on other planets. Survival was investigated by evaluating colony forming units, damage inflicted to the 16S rRNA gene by quantitative PCR, and the integrity and detectability of deinoxanthin by Raman spectroscopy. Exposure to space conditions had a strong detrimental effect on the survival of the strains and the 16S rRNA integrity, yet results show that deinoxanthin survives exposure to conditions as they prevail on Mars. Solar radiation is not only strongly detrimental to the survival and 16S rRNA integrity but also to the Raman signal of deinoxanthin. Samples not exposed to solar radiation showed only minuscule signs of deterioration. To test whether deinoxanthin is able to withstand the tested parameters without the protection of the cell, it was extracted from cell homogenate and exposed to high/low temperatures, vacuum, germicidal UV-C radiation, and simulated solar radiation. Results obtained by Raman investigations showed a strong resistance of deinoxanthin against outer space and Mars conditions, with the only exception of the exposure to simulated solar radiation. Therefore, deinoxanthin proved to be a suitable easily detectable biomarker for the search of Earth-like organic pigment-containing life on other planets.

The influence of the wavelength of ultraviolet radiation on survival, mutation induction and DNA repair in irradiated Chinese hamster cells

International Nuclear Information System (INIS)

Zelle, B.; Reynolds, R.J.; Kottenhagen, M.J.; Schuite, A.; Lohmann, P.H.M.

1980-01-01

Chinese hamster ovary cells were used to compare the cytotoxicity and mutagenicity of far-UV radiation emitted by a low-pressure mercury, germicidal lamp (wavelength predominantly 254 nm) with that of near UV radiation emitted by a fluorescent lamp with a continuous spectrum (Westinghouse Sun Lamp), of which only the radiation with wavelengths greater than 290 nm or greater than 310 nm was transmitted to the cells. The radiation effects were compared on the basis of an equal number of pyrimidine dimers, the predominant lesion induced in DNA by far-UV, for the induction of which much more energy is needed with near-UV than with 254-nm radiation. The numbers of dimers induced were determined by a biochemical method detecting UV-endonuclease-susceptible sites. The equivalence of these sites with pyrimidine dimers was established, qualitatively and quantitatively, in studies with enzymic photoreactivation in vitro and chromatographic analysis of dimers. On the basis of induced dimers, more cells were killed by UE 310-nm UV than by UE 290-nm UV; both forms of radiation were more cytotoxic than 254-nm UV when equal numbers of dimers were induced. Moreover, 5-6 times as many mutants were induced per dimer by UE 310-nm UV than by UE 290-nm UV; the latter appeared approximately as mutagenic as 254-nm UV. The differences in lethality and mutagenicity were not caused by differences in repair of dimers: cells with an equal number of dimers induced by either 254-nm or near-UV showed the same removal of sites susceptible to a UV endonuclease specific for dimers, as well as an identical amount of repair replication. The results indicate that near-UV induces, besides pyrimidine dimers, other lesions that appear to be of high biological significance. (orig.)

Trace Contaminant Control: An In-Depth Study of a Silica-Titania Composite for Photocatalytic Remediation of Closed-Environment Habitat Air

Science.gov (United States)

Coutts, Janelle L.

2013-01-01

This collection of studies focuses on a PCO system for the oxidation of a model compound, ethanol, using an adsorption-enhanced silica-TiO2 composite (STC) as the photocatalyst; studies are aimed at addressing the optimization of various parameters including light source, humidity, temperature, and possible poisoning events for use as part of a system for gaseous trace-contaminant control system in closed-environment habitats. The first goal focused on distinguishing the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the PCO of ethanol. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp O max=365 nm) at its maximum light intensity or a UV-C germicidal lamp O. max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM s-1 ) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol C02 mol photons-1 ). UV-C irradiation also led to decreased intermediate concentration in the effluent compared to UV -A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy. The effect of temperature and relative humidity on the STC-catalyzed degradation of ethanol was also determined using the UV-A light source at its maximum intensity.

Biodegradation of high concentrations of phenol by baker’s yeast in anaerobic sequencing batch reactor

Directory of Open Access Journals (Sweden)

Ali Asghar Najafpoor

2015-06-01

Full Text Available Background: Phenol, as a pure substance, is used in many fields because of its disinfectant, germicidal, local anesthetic, and peptizing properties. Aqueous solutions of phenol are produced as waste in industries and discharged into the environment. Therefore, elevated concentrations of phenol may be found in air or water because of industrial discharge or the use of phenolic products. Method: The strains of Saccharomyces cerevisiae used in this project were natural strains previously purchased from Razavy company. They were grown at 30°C on Petri plates containing yeast extract glucose (YGC and then purified by being spread onto new plates, and isolated colonies were obtained. These colonies provided the basis of selection. Prepared strains were applied in anaerobic sequencing batch reactors (ASBRs as first seed. The experiment conditions were optimized using response surface methodology (RSM. After the determined runs were performed using Design-Expert software, data were analyzed using mentioned software as well. Results: This study evaluated the capability of baker’s yeast to remove phenol in high concentrations. The tested strains showed excellent tolerance to phenol toxicity at concentrations up to 6100 mg/L. Study of the batch degradation process showed that the phenol removal rate could exceed 99.9% in 24 hours at a concentration of 1000 mg/L. The results showed catechol is the first intermediate product of phenol degradation. In survey results of the Design–Expert software, R2 and Adeq precision were 0.97 and 25.65, respectively. Conclusion: The results demonstrated that ASBR performs robustly under variable influent concentrations of inhibitory compounds. The high removal performance despite the high phenol concentration may be a result of reactor operating strategies. Based on the progressive increase of inlet phenol concentration, allowing for an enhanced biomass acclimation in a short time, results at the microbiological levels

Continuous-flow solar UVB disinfection reactor for drinking water.

Science.gov (United States)

Mbonimpa, Eric Gentil; Vadheim, Bryan; Blatchley, Ernest R

2012-05-01

Access to safe, reliable sources of drinking water is a long-standing problem among people in developing countries. Sustainable solutions to these problems often involve point-of-use or community-scale water treatment systems that rely on locally-available resources and expertise. This philosophy was used in the development of a continuous-flow, solar UVB disinfection system. Numerical modeling of solar UVB spectral irradiance was used to define temporal variations in spectral irradiance at several geographically-distinct locations. The results of these simulations indicated that a solar UVB system would benefit from incorporation of a device to amplify ambient UVB fluence rate. A compound parabolic collector (CPC) was selected for this purpose. Design of the CPC was based on numerical simulations that accounted for the shape of the collector and reflectance. Based on these simulations, a prototype CPC was constructed using materials that would be available and inexpensive in many developing countries. A UVB-transparent pipe was positioned in the focal area of the CPC; water was pumped through the pipe to allow exposure of waterborne microbes to germicidal solar UVB radiation. The system was demonstrated to be effective for inactivation of Escherichia coli, and DNA-weighted UV dose was shown to govern reactor performance. The design of the reactor is expected to scale linearly, and improvements in process performance (relative to results from the prototype) can be expected by use of larger CPC geometry, inclusion of better reflective materials, and application in areas with greater ambient solar UV spectral irradiance than the location of the prototype tests. The system is expected to have application for water treatment among communities in (developing) countries in near-equatorial and tropical locations. It may also have application for disaster relief or military field operations, as well as in water treatment in areas of developed countries that receive

Free chlorine loss during spraying of membraneless acidic electrolyzed water and its antimicrobial effect on airborne bacteria from poultry house

Directory of Open Access Journals (Sweden)

Yang Zhao

2014-06-01

Full Text Available introduction. Spray-application of membraneless acidic electrolyzed water (MLAEW is a novel technique for disinfection in livestock houses. This study investigated the loss of free chlorine (FC – the major germicidal component in MLAEW over distance during spraying, as affected by air temperature and initial FC concentration. The anti-microbial effect of MLAEW on airborne bacteria from an aviary laying-hen house was examined. materials and methods. MLAEW was prepared at two FC concentrations: app. 15 and 60 mg L -1 , and sprayed at three air temperatures (18, 25, 32 °C. The original MLAEW solution and MLAEW aerosols collected at 0, 25, and 50 cm from the spray nozzle were analyzed for FC concentrations. Bacteria were immersed into these MLAEW samples and numerated for viable count after 0.5, 2 and 5-min treatments. results. MLAEW aerosols collected at 0 cm lost 11.7–13.2% FC, compared with the original MLAEW solution. This initial loss was affected neither by the initial FC concentration (P = 0.13 nor by air temperature (P = 0.57. The rate of FC loss during travelling was 0.79–0.87 % per cm of aerosol travel distance (% cm -1 at 18 °C, 1.08–1.15 % cm -1 at 25 °C, and 1.35–1.49% cm -1 at 32 °C. This travelling loss was affected by air temperature (P = 0.02, but not by initial FC concentration (P = 0.38. Bacteria were completely inactivated at 0.5 min when treated with MLAEW samples with FC > 16.8 mg L -1 , in 2 min when FC > 13.8 mg L -1 , and in 5 min when FC > 7.2 mg L -1 . conclusion. Airborne bacteria from aviary hen house can be effectively inactivated by MLAEW with adequate FC concentration and contact time. During spraying, the anti-microbial efficacy of MLAEW aerosols decreased over distance due to FC loss which exacerbated at higher air temperatures.

CARAWAY (Carum carvi L.

Directory of Open Access Journals (Sweden)

I. T. Ushakova

2016-01-01

Full Text Available Description information on the origin, biological features, nutritional and medical benefits of caraway has been given. Caraway Carum carvi L. is a biennial, herb plant. It is lightdemanding and winter-hardy. First year it grows a rosette of leaves, the second year it produces the flower-bearing stems and later seeds. The medicinal raw material is seeds which are picked just before the time of full maturity. The seeds content up to 20 % of proteins, 25.5 % of fatty oil, 8 % of essential oil, and vitamins, flavonoids, minerals are also present. The seeds and essential oil are used in medicine, in soap manufacture, distillery, confectionery making, bread bakery, perfumery, cosmetics products and agriculture. The caraway seeds are used in veterinary medicine to treat some disease in animals. The caraway fruit possess germicidal, antispasmodic, anesthetic, cholagogic, bileexpelling effects. The seeds can be used as diuretic, stomachic and carminative agents. The seeds of caraway increase milk production in livestock, and also are useful for human's nourishing. Usage of caraway assists to discharge sputum and mucus at lung diseases. Caraway is the excellent melliferous  plant, since the flowers bear much nectar. Production of honey can reach up to 100 kg per one hectare on average. Leaves and shoots of caraway are used in cuisine for salad recipes and to add flavor to meat and fish meal. The fleshy roots could be also consumed as root vegetable. Caraway fruits as a fragrance component are added for cucumber salting, cabbage fermentation and kvass preparation. This article presents the agricultural features for caraway cultivation in middle Russian region. The cultivar ‘Peresvet’ has been bred at VNIISSOK and included in State Register of Breeding Achievements of Russian Federation.

Bromination vis-a-vis chlorination as a biocide feasibility study

International Nuclear Information System (INIS)

Upadhyay, S.K.; Nagaigh, N.; Mittal, S.

2000-01-01

Water is used extensively as a cooling medium in various heat transfer equipment's of a power industry such as condenser, heat exchangers and cooling towers. At elevated temperature, the breeding of microbiological growth can form slimes, underneath of this, accelerated corrosion can take place resulting into sudden and catastrophic failure of equipment's. The microbiological growth unchecked in the various systems especially in low velocity areas can lead to large growth of micro organisms such as algae which can even reduce the flow of the fluid thus affecting the efficiency of plant equipment's. Therefore, chlorination is a mandatory requirement in industrial cooling water to reduce biofouling in heat transfer equipment's. The chlorination in drinking water produces germicidal effect and thus reduces the bacterial counts. At NAPS the water quality is good and mild doses of chlorine (5 ppm) two times a day, as envisaged in design is noticed to be satisfactory. The chlorination of recirculating condenser cooling water presently is being done with the established doses for a fixed time twice a day. Some of the problems noticed with the chlorination process are : Corrosion of constructional material of chlorination plant and equipment's and pipelines causing large input of efforts on maintenance for keeping high availability of the chlorination plant. In addition to this, the leakages in the equipment could be a potential safety hazard. The effectiveness of chlorine is observed to be less in alkaline pH (above 9.0) as encountered at NAPS. This results is large quantities of chlorine injection for extended periods. The cost of chlorine and bleaching powder keeps fluctuating in the market as noticed in past few years. Many a times this results in scarcity of chlorine/bleaching powder causing interruption in biofouling control programme. Hence it was felt prudent to work on the alternative biocides which could be cost effective, non-polluting and nature and user

Analysis of the potencial of natural illumination for the savings and efficient use of the energy in buildings located in hot climates; Analisis del potencial de la iluminacion natural para ahorro y uso eficiente de la energia en las edificaciones en climas calidos

Energy Technology Data Exchange (ETDEWEB)

Garcia Chavez, J. R. [Universidad Autonoma Metropolitana-Azcapotzalco, Division de Ciencias y Artes para el Diseno, Departamento de Medio Ambiente, (Mexico)

1997-12-31

Daylight is an essential factor in lightening buildings. Its use is not only oriented to supply illumination to the spaces to provide adequate lightening levels for the optimum execution of their occupants` tasks, but also to supply the appropriate illumination level required in each case for specific functions, as well as to contribute to the psychophysiological health of its users and provide a favorable ambient and the germicide action in the ultraviolet component of the sunlight and besides a portion of vitamin {sup D,} that is needed for people`s health. On the other hand, the rational and efficient use of daylight can contribute to the diminish the consumption of electric power, that is used for the artificial lightning of buildings. This situation is particularly important in hot climates, where the consumption of electricity for lightening interior spaces is huge, mainly in non-dwelling buildings. In this paper the possibilities of the utilization of daylight are explored and analyzed for the purpose of achieving energy savings and the visual thermal and lightning comfort in buildings. [Espanol] La luz natural diurna es un factor indispensable en los edificios. Su uso no solamente esta orientado a proveer de iluminacion a los espacios para proporcionar niveles de iluminancia adecuados para la optima realizacion de las tareas visuales de los ocupantes, sino tambien para proporcionar la calidad luminica que se requiere para cada caso y funcion especificas, asi como contribuir a la salud psicofisiologica de los usuarios al brindarles un ambiente favorable y la accion germicida en la componente ultravioleta luminica y ademas, un contenido de vitamina {sup D,} necesario para la salud de las personas. Por otra parte, el uso sensato y eficiente de la luz natural diurna puede contribuir a reducir el consumo de energia electrica que se utiliza para el alumbrado artificial de los edificios. Esta situacion es de particular importancia en climas calidos, donde los

New airborne pathogen transport model for upper-room UVGI spaces conditioned by chilled ceiling and mixed displacement ventilation: Enhancing air quality and energy performance

International Nuclear Information System (INIS)

Kanaan, Mohamad; Ghaddar, Nesreen; Ghali, Kamel; Araj, Georges

2014-01-01

Highlights: • A model of bacteria transport is developed in CC/DV conditioned spaces with UVGI. • The model identifies buoyant, partially mixed, and fully mixed transport zones. • The predicted bacteria concentration agreed well with CFD results. • The higher the supply flow rate, the more restrictive is return air mixing ratio. • Upper-room UVGI results in higher return mixing and 33% in energy savings. - Abstract: The maximum allowable return air ratio in chilled ceiling (CC) and mixed displacement ventilation (DV) system for good air quality is regulated by acceptable levels of CO 2 concentration not to exceed 700 ppm and airborne bacterial count to satisfy World Health Organization (WHO) requirement for bacterial count not to exceed 500 CFU/m 3 . Since the CC/DV system relies on buoyancy effects for driving the contaminated air upwards, infectious particles will recirculate in the upper zone allowing effective utilization of upper-room ultraviolet germicidal irradiation (UVGI) to clean return air. The aim of this work is to develop a new airborne bacteria transport plume-multi-layer zonal model at low computational cost to predict bacteria concentration distribution in mixed CC/DV conditioned room without and with upper-room UVGI installed. The results of the simplified model were compared with layer-averaged concentration predictions of a detailed and experimentally-validated 3-D computational fluid dynamics (CFD) model. The comparison showed good agreement between bacteria transport model results and CFD predictions of room air bacteria concentration with maximum error of ±10.4 CFU/m 3 in exhaust air. The simplified model captured the vertical bacteria concentration distribution in room air as well as the locking effect of highest concentration happening at the stratification level. The developed bacteria transport model was used in a case study to determine the return air mixing ratio that minimizes energy consumption and maintains acceptable IAQ

Analysis of the potencial of natural illumination for the savings and efficient use of the energy in buildings located in hot climates; Analisis del potencial de la iluminacion natural para ahorro y uso eficiente de la energia en las edificaciones en climas calidos

Energy Technology Data Exchange (ETDEWEB)

Garcia Chavez, J R [Universidad Autonoma Metropolitana-Azcapotzalco, Division de Ciencias y Artes para el Diseno, Departamento de Medio Ambiente, (Mexico)

1998-12-31

Daylight is an essential factor in lightening buildings. Its use is not only oriented to supply illumination to the spaces to provide adequate lightening levels for the optimum execution of their occupants` tasks, but also to supply the appropriate illumination level required in each case for specific functions, as well as to contribute to the psychophysiological health of its users and provide a favorable ambient and the germicide action in the ultraviolet component of the sunlight and besides a portion of vitamin {sup D,} that is needed for people`s health. On the other hand, the rational and efficient use of daylight can contribute to the diminish the consumption of electric power, that is used for the artificial lightning of buildings. This situation is particularly important in hot climates, where the consumption of electricity for lightening interior spaces is huge, mainly in non-dwelling buildings. In this paper the possibilities of the utilization of daylight are explored and analyzed for the purpose of achieving energy savings and the visual thermal and lightning comfort in buildings. [Espanol] La luz natural diurna es un factor indispensable en los edificios. Su uso no solamente esta orientado a proveer de iluminacion a los espacios para proporcionar niveles de iluminancia adecuados para la optima realizacion de las tareas visuales de los ocupantes, sino tambien para proporcionar la calidad luminica que se requiere para cada caso y funcion especificas, asi como contribuir a la salud psicofisiologica de los usuarios al brindarles un ambiente favorable y la accion germicida en la componente ultravioleta luminica y ademas, un contenido de vitamina {sup D,} necesario para la salud de las personas. Por otra parte, el uso sensato y eficiente de la luz natural diurna puede contribuir a reducir el consumo de energia electrica que se utiliza para el alumbrado artificial de los edificios. Esta situacion es de particular importancia en climas calidos, donde los

Particle integrity, sampling, and application of a DNA-tagged tracer for aerosol transport studies

Energy Technology Data Exchange (ETDEWEB)

Kaeser, Cynthia Jeanne [Michigan State Univ., East Lansing, MI (United States)

2017-07-21

Aerosols are an ever-present part of our daily environment and have extensive effects on both human and environmental health. Particles in the inhalable range (1-10 μm diameter) are of particular concern because their deposition in the lung can lead to a variety of illnesses including allergic reactions, viral or bacterial infections, and cancer. Understanding the transport of inhalable aerosols across both short and long distances is necessary to predict human exposures to aerosols. To assess the transport of hazardous aerosols, surrogate tracer particles are required to measure their transport through occupied spaces. These tracer particles must not only possess similar transport characteristics to those of interest but also be easily distinguished from the background at low levels and survive the environmental conditions of the testing environment. A previously-developed DNA-tagged particle (DNATrax), composed of food-grade sugar and a DNA oligonucleotide as a “barcode” label, shows promise as a new aerosol tracer. Herein, the use of DNATrax material is validated for use in both indoor and outdoor environments. Utilizing passive samplers made of materials commonly found in indoor environments followed by quantitative polymerase chain reaction (qPCR) assay for endpoint particle detection, particles detection was achieved up to 90 m from the aerosolization location and across shorter distances with high spatial resolution. The unique DNA label and PCR assay specificity were leveraged to perform multiple simultaneous experiments. This allowed the assessment of experimental reproducibility, a rare occurrence among aerosol field tests. To transition to outdoor testing, the solid material provides some protection of the DNA label when exposed to ultraviolet (UV) radiation, with 60% of the DNA remaining intact after 60 minutes under a germicidal lamp and the rate of degradation declining with irradiation time. Additionally, exposure of the DNATrax material using

Failure Analysis of Pitted Copper Pipes Used in Underground Water and Preventive Measures

Science.gov (United States)

Nam, Gi-ho; Lee, Jong-kwon; Kim, Kyung-ja

2018-05-01

This study performed an experiment on the causes of pitting corrosion in a copper tubing used for a sprinkler system. Corrosion products of a copper tubing that sustained pitting corrosion were collected and cultured in Culture medium [Luria-Bertani, Brain heart infusion, Tryptic soy broth (TSB), R2A]. Four types of bacteria were found through identification: Micrococcus luteus sp (species)., Staphylococcus sp., Sphingomonas sp., and Bacillus sp. The copper toxicity test was performed for each microorganism. Among the four microorganisms, Micrococcus luteus sp. showed good growth in the environment containing copper ions. On the immersion test, changes in pH and Optical density were measured; On the inductively coupled plasma optical emission spectrometry test, the copper concentration of each culture medium was measured. The surface of each copper sample was observed using a scanning electron microscope. The corrosion potential of a copper sample, after 48 h exposure of the TSB medium containing Micrococcus luteus sp., was measured using a potentiodynamic polarization experiment. The next experiment was conducted to prevent microbial corrosion by suppressing the growth of microorganisms. Six 30 ml TSB culture media with controlled pH value of 4, 5, 6, 7, 8, and 9 through HCl and NaOH were manufactured. Then the microorganisms were cultured in 37 °C 133 rpm, of which the growth status was checked every 24 h for 3 days. It was found that microorganisms did not grow on culture media with the pH value of 6 and lower. The same experiment conducted on culture media controlled with acetic acid, nitric acid, and sulfuric acid, also showed no growth of microorganisms on media with pH value of 6 and lower. Six 5 ml TSB culture media each containing 0.5, 0.25, 0.125, 0.0625, 0.0312%, and 0.0156% NaOCl and NaOBr as germicides were manufactured. 0.01 μl of microorganisms were inoculated on the media and cultured in 37 °C for 48 h. It was found that microorganisms did not

Photocatalytic and biocidal activities of novel coating systems of mesoporous and dense TiO{sub 2}-anatase containing silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Roldán, María V. [Laboratorio de Materiales Cerámicos, FCEIA-UNR, IFIR-CONICET, Pellegrini 250, Rosario S2000BTP (Argentina); Oña, Paula de [Laboratorio de Microbiología Molecular, FCByF-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Castro, Yolanda; Durán, Alicia [Instituto de Cerámica y Vidrio (CSIC), Campus de Cantoblanco, 28049, Madrid (Spain); Faccendini, Pablo; Lagier, Claudia [IQUIR-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Grau, Roberto, E-mail: robertograu@fulbrightmail.org [Laboratorio de Microbiología Molecular, FCByF-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Pellegri, Nora S., E-mail: pellegri@fceia.unr.edu.ar [Laboratorio de Materiales Cerámicos, FCEIA-UNR, IFIR-CONICET, Pellegrini 250, Rosario S2000BTP (Argentina)

2014-10-01

Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise a layer of SiO{sub 2} followed by a layer of mesoporous or dense TiO{sub 2}-anatase, and doping with silver nanoparticles (Ag NPs). The coatings were synthesized via a sol–gel technique by combining colloidal Ag NPs with TiO{sub 2} and SiO{sub 2} sols. The photocatalytic activity was studied through methyl orange decomposition under UV light. Results showed a great increase of photocatalytic activity by Ag NPs doping. The most active photocatalyst corresponded to the Ag–SiO{sub 2}/TiO{sub 2} mesoporous system, associated with the porosity of the coatings and with the decrease of e–h recombination for the presence of Ag NPs. All the TiO{sub 2} coatings showed a strong bactericidal activity against planktonic forms of Gram-negative (enterohemorrhagic Escherichia coli) and Gram-positive (Listeria monocytogenes) pathogens, as well as a strong germicidal effect against deadly spores of human gas gangrene- and anthrax-producing bacteria (Clostridium perfringens and Bacillus anthracis, respectively). The bactericidal and sporocidal activity was improved by doping the coatings with Ag NPs, even more when nanoparticles were in the outer layer of TiO{sub 2}, because they are more accessible to the environment. The mechanisms responsible for the increase of photocatalytic and bactericidal behaviors related to Ag NP doping were studied by spectroscopic ellipsometry, UV–vis spectroscopy, photoluminescence and anodic stripping voltammetry. It was found that the separation of the electron–hole pair contributed to the enhancement of photocatalysis, whereas the effect of the local electric field reinforcement was probably present. A possible involvement of a decrease of band-gap energy and dispersion by silver nanoparticles is ruled out. bactericidal efficacy was increased by Ag{sup +} ion release. Overall, the results

El cloruro de benzalconio: inaceptable para esterilizar o desinfectar instrumental médico o dental Benzalkonium chloride is unacceptable to sterilize or disinfect medical or dental instruments

Directory of Open Access Journals (Sweden)

Enrique Acosta-Gío

2001-12-01

Full Text Available Objetivo. Comparar la actividad esporicida del cloruro de benzalconio (CB con la del glutaraldehído. Material y métodos. Estudio comparativo, hecho en el Laboratorio de Microbiología de la Facultad de Odontología, Universidad Nacional Autónoma de México (UNAM. Se expusieron esporas de Bacillus subtilis ATCC 9372 a estos germicidas (1 espora x µl sobre un filtro de 0.22 µm. Al completarse el tiempo de contacto, se lavaron las esporas y los filtros fueron incubados sobre agar nutritivo por 72 h a 37ºC. Resultados. El CB no eliminó las esporas de B. subtilis a la concentración de uso, ni aun al incrementar a 15 h su exposición (900 veces el tiempo recomendado. El glutaraldehído al 2% destruyó las esporas después de 10 h. La urea y el cloruro de sodio no mostraron actividad esporicida. Conclusiones. Los resultados confirman que el CB carece de actividad esporicida y ratifican que este compuesto cuaternario de amonio no tiene aplicación como agente esterilizante o como desinfectante de instrumental médico y dental. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.htmlObjective. To compare the sporicidal activity of benzalkonium chloride (BKC with that of glutaraldehyde. Material and Methods. A comparative study was conducted at the microbiology laboratory of Facultad de Odontología, Universidad Nacional Autónoma de México. Bacillus subtilis ATCC 9372 spores were exposed to these germicides (1 spore x mL on a 0.22 mm filter. After completing the contact time the spores were washed and the filters were incubated on nutrient agar for 72 h at 37ºC. Results. BKC did not eliminate B. subtilis spores at the concentration used, not even after increasing contact time to 15 h (900-fold the recommended time. Two percent glutaraldehyde destroyed spores only after 10 h of contact. Urea and sodium chloride showed no sporicidal activity. Conclusions. The results confirm that BKC lacks sporicidal

Failure Analysis of Pitted Copper Pipes Used in Underground Water and Preventive Measures

Science.gov (United States)

Nam, Gi-ho; Lee, Jong-kwon; Kim, Kyung-ja

2018-03-01

This study performed an experiment on the causes of pitting corrosion in a copper tubing used for a sprinkler system. Corrosion products of a copper tubing that sustained pitting corrosion were collected and cultured in Culture medium [Luria-Bertani, Brain heart infusion, Tryptic soy broth (TSB), R2A]. Four types of bacteria were found through identification: Micrococcus luteus sp (species)., Staphylococcus sp., Sphingomonas sp., and Bacillus sp. The copper toxicity test was performed for each microorganism. Among the four microorganisms, Micrococcus luteus sp. showed good growth in the environment containing copper ions. On the immersion test, changes in pH and Optical density were measured; On the inductively coupled plasma optical emission spectrometry test, the copper concentration of each culture medium was measured. The surface of each copper sample was observed using a scanning electron microscope. The corrosion potential of a copper sample, after 48 h exposure of the TSB medium containing Micrococcus luteus sp., was measured using a potentiodynamic polarization experiment. The next experiment was conducted to prevent microbial corrosion by suppressing the growth of microorganisms. Six 30 ml TSB culture media with controlled pH value of 4, 5, 6, 7, 8, and 9 through HCl and NaOH were manufactured. Then the microorganisms were cultured in 37 °C 133 rpm, of which the growth status was checked every 24 h for 3 days. It was found that microorganisms did not grow on culture media with the pH value of 6 and lower. The same experiment conducted on culture media controlled with acetic acid, nitric acid, and sulfuric acid, also showed no growth of microorganisms on media with pH value of 6 and lower. Six 5 ml TSB culture media each containing 0.5, 0.25, 0.125, 0.0625, 0.0312%, and 0.0156% NaOCl and NaOBr as germicides were manufactured. 0.01 μl of microorganisms were inoculated on the media and cultured in 37 °C for 48 h. It was found that microorganisms did not

Optical emission spectroscopy for quantification of ultraviolet radiations and biocide active species in microwave argon plasma jet at atmospheric pressure

Energy Technology Data Exchange (ETDEWEB)

Wattieaux, G., E-mail: gaetan.wattieaux@laplace.univ-tlse.fr; Yousfi, M.; Merbahi, N.

2013-11-01

This work deals with absorption and mainly emission spectrometry of a microwave induced surfatron plasma jet launched in ambient air and using an Argon flow carrier gas. The Ar flow rate varies between 1 and 3 L/min and the microwave power between 40 and 60 W. The analysis of the various spectra has led to the determination of the ozone and atomic oxygen concentrations, ultraviolet (UV) irradiance separating UVA, UVB and UVC, gas temperature, plasma electron density and excitation temperature. Most of these diagnostics are spatially resolved along the plasma jet axis. It is shown more particularly that rotational temperature obtained from OH(A-X) spectra ranges between 800 K to 1000 K while the apparent temperature of the plasma jet remains lower than about 325 K which is compatible with biocide treatment without significant thermal effect. The electron density reaches 1.2 × 10{sup 14} cm{sup −3}, the excitation temperature is about 4000 K, the UVC radiation represents only 5% of the UV radiations emitted by the device, the ozone concentration is found to reach 88 ± 27 ppm in the downstream part of the plasma jet at a distance of 30 mm away from the quartz tube outlet of the surfatron and the atomic oxygen concentration lies between 10 and 80 ppm up to a distance of 20 mm away from the quartz tube outlet. Ozone is identified as the main germicidal active species produced by the device since its concentration is in accordance with bacteria inactivation durations usually reported using such plasma devices. Human health hazard assessment is carried out all along this study since simple solutions are reminded to respect safety standards for exposures to ozone and microwave leakage. In this study, an air extraction unit is used and a Faraday cage is set around the quartz tube of the surfatron and the plasma jet. These solutions should be adopted by users of microwave induced plasma in open air conditions because according to the literature, this is not often the

Optical emission spectroscopy for quantification of ultraviolet radiations and biocide active species in microwave argon plasma jet at atmospheric pressure

International Nuclear Information System (INIS)

Wattieaux, G.; Yousfi, M.; Merbahi, N.

2013-01-01

This work deals with absorption and mainly emission spectrometry of a microwave induced surfatron plasma jet launched in ambient air and using an Argon flow carrier gas. The Ar flow rate varies between 1 and 3 L/min and the microwave power between 40 and 60 W. The analysis of the various spectra has led to the determination of the ozone and atomic oxygen concentrations, ultraviolet (UV) irradiance separating UVA, UVB and UVC, gas temperature, plasma electron density and excitation temperature. Most of these diagnostics are spatially resolved along the plasma jet axis. It is shown more particularly that rotational temperature obtained from OH(A-X) spectra ranges between 800 K to 1000 K while the apparent temperature of the plasma jet remains lower than about 325 K which is compatible with biocide treatment without significant thermal effect. The electron density reaches 1.2 × 10 14 cm −3 , the excitation temperature is about 4000 K, the UVC radiation represents only 5% of the UV radiations emitted by the device, the ozone concentration is found to reach 88 ± 27 ppm in the downstream part of the plasma jet at a distance of 30 mm away from the quartz tube outlet of the surfatron and the atomic oxygen concentration lies between 10 and 80 ppm up to a distance of 20 mm away from the quartz tube outlet. Ozone is identified as the main germicidal active species produced by the device since its concentration is in accordance with bacteria inactivation durations usually reported using such plasma devices. Human health hazard assessment is carried out all along this study since simple solutions are reminded to respect safety standards for exposures to ozone and microwave leakage. In this study, an air extraction unit is used and a Faraday cage is set around the quartz tube of the surfatron and the plasma jet. These solutions should be adopted by users of microwave induced plasma in open air conditions because according to the literature, this is not often the case

Effect of UV C irradiation on P53 in FADD+/+ and FADD-/- cells

International Nuclear Information System (INIS)

Matic, Igor; Radnic, Maja; Marijanovic, Inga; Furcic, Ivana; Nagy, Biserka

2008-01-01

The dominant paradigm of tumor biology is that evasion from apoptosis is one of the crucial features of malignant diseases and that the efficiency of cancer therapy depends on P53-dependent apoptosis. Because of the importance of apoptotic pathways in protecting cells against malignant transformation, disruption of apoptosis is extremely common in cancer cells, and is frequently due to mutations in the P53 tumor suppressor gene. Fas-associated death domain (FADD) is an adapter protein that is required for apoptosis induced by all known death receptors. FADD is implicated in death receptor-independent apoptotic response, such as DNA damage. We used embryonic fibroblasts derived from FADD knockout mice and their genetic counterparts. We predicted that UV exposure induces a loss of FADD function and leads to mutations in P53. Loss of FADD expression causes deregulation of apoptosis and expansion of mutated cells and initiation of cancer. We predicted that FADD dysfunction may be potentially advantageous for tumor growth and that FADD can act as a tumor suppressor. Cells were irradiated with UV C light (254 nm) using a germicidal lamp (Upland, CA). The culture media was drained before the irradiation and fresh media was added after. In the first experiment we irradiated cells with a dose of 25 J/m 2 and after 5 days we isolated genomic DNA but part of the cells were irradiated again with the same dose. After 5 days DNA were isolated so the cumulative irradiation dose was 50 J/m 2 . In the second experiment cells were irradiated ones with the dose of 40 J/m 2 and DNA was isolated after 18 days. Lethal dosage for each cell line is 50 J/m 2 . Genomic DNA was analyzed by allele-specific polymerase chain reaction (AS-PCR) for CC to TT mutation at codons 154-155 and 175-176 in exon 5 and for C to T mutations at codons 270 and 275 in exon 8 of the P53 gene. The mutant-specific forward primer was used for each mutation. The reverse primers for amplification of mutations were

Studies on the electrochemical disinfection of water containing Escherichia coli using a Dimensionally Stable Anode

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Isabel Celeste Caíres Pereira Gusmão

2010-10-01

Full Text Available The aim of this work was to investigate the disinfectant effect of electrolysis on chlorine-free water, artificially contaminated with Escherichia coli (CCT-1457 and to evaluate the bactericidal activity of electrolysis and kinetic behavior of a single-cell reactor, with a DSA (Dimensionally Stable Anode electrode to develop a scaled-up system. A high-density E. coli suspension (10(6 CFU mL-1 was electrolyzed in this reactor at 25, 50 and 75 mA cm-2 for up to 60 min, at flow rates of 200 and 500 L h-1. Bacterial survival fell by 98.9% without addition of chlorinated compounds and a power consumption rate not more than 5.60 kWh m-3 at flow rate of 200 L h-1 and 75 mA cm-2. The process produced a germicidal effect that reached this inactivation rate within a relatively short contact time. Also, a solution of electrolyzed 0.08 M Na2SO4 added to the inoculum showed residual bactericidal effect. The efficiency of disinfection was regulated by both the contact time and current density applied, and a kinetic function for the survival rate was developed for the purpose of scaling up.Água contaminada é uma das maiores origens de doenças em seres humanos. Em todo o mundo, a cloração é o método mais utilizado para promover desinfecção em águas de abastecimento devido ao seu efeito residual, quando adequadamente calculado. Contudo, se a água apresentar matéria orgânica, pode haver a geração de organoclorados, os quais são genotóxicos e carcinogênicos. Sob esta óptica, investigamos o efeito bactericida da aplicação da eletrólise em água sem cloro contaminada com Escherichia coli (CCT-1457. O objetivo deste estudo foi avaliar o poder de desinfecção e o comportamento cinético da eletrólise realizada em reator de compartimento único e usando eletrodos ADE (Anodo Dimensionalmente Estável, visando ampliação de escala. Uma suspensão contendo elevada concentração de E. coli (10(6 UFC mL-1 foi submetida ao tratamento no reator em 25

CLINICAL EVALUATION OF PREOPERATIVE SKIN PREPARATION WITH AQUEOUS POVIDONE IODINE ONLY AND IN COMBINATION WITH ALCHOLIC CHLORHEXIDINE IN PATIENTS UNDERGOING ELECTIVE AND EMERGENCY SURGERIES

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Latchu

2015-10-01

Full Text Available INTRODUCTION: Many techniques are there for skin preparation before surgery, the commonest being initial scrub with antiseptic soap solution, followed by painting the prepared area with antiseptic paint solution. But degerming of the skin can be done with antiseptics us ed for less than one minute which is as effective as five minute scrub with germicidal soap solution followed by painting with antiseptics . AIMS AND OBJECTIVES : 1. To evaluate the efficacy of povidone iodine alone and antiseptic agent containing alcoholic chlorhexidine with povidone iodine in preoperative skin preparation by taking swab culture. 2. To compare the rate of postoperative wound infection in both the groups . METHODS: STUDY DESIGN: Comparative study conducted on 100 patients in two groups. STUDY SETTING: Sri Venkateswara Medical College Tirupathi SOURCE OF DATA: 100 Patients (50 in each Group undergoing elective and emergency surgery admitted in the Department of General Surgery in S.V.R.R. Government General Hospital, Tirupati from 2013 to 2014. INCLUSION CRITERIA: 1. Patients undergoing elective & emergency surgery in department of general surgery. 2. Patients with no focus of infection anywhere on the body. 3. Patients irrespective of their age and sex. 4. Patients neither immunocompromised nor on any long term steroids. 5. Patients undergoing mes h repair of hernia are also included. EXCLUSION CRITERIA: 1. Immuno compromised patients and patients on long term steroids. 2. Patients with septicemia. 3. Patients suffering from malignancies or undergoing chemotherapy or radiation therapy. 4. Contaminat ed surgeries in which viscus was opened were excluded from the study. 5. Patients with co - morbid medical conditions like diabetes, hypertension etc. METHOD OF COLLECTION OF DATA: In each case preoperatively, detailed history was taken and routine investiga tions like haemoglobin, total count, differential count, ESR, RBS and chest X - ray, ultrasound were done to

Nuclear techniques in food and agriculture and international cooperation in their use; Les sciences nucleaires dans l'alimentation et l'agriculture et la cooperation internationale dans ce domaine

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Fried, M.; Sigurbjörnsson, B. [Joint FAO/IAEA Division of Atomic Energy in Food and Agriculture, International Atomic Energy Agency, Vienna (Austria)

1970-01-15

'insectes stérilisés aboutissent rapidement à la réduction de cette population et peuvent finalement entraîner la destruction complète de l'espèce dans la zone. La lucilie bouchère, qui s'attaque au bétail» a ainsi été éliminée aux Etats-Unis et on espère pouvoir détruire de la même façon la mouche méditerranéenne des fruits, qui s'attaque aux citrus, la mouche de l'olive, la carpocapse, qui s'attaque aux pommes, la mouche tsé-tsé et plusieurs autres insectes. Les rayonnements peuvent être utilisés pour atténuer les larves des parasites des animaux. Avec les parasites ayant ainsi perdu leur virulence, on prépare des vaccins animaux. Il s'agit en fait de la seule méthode actuellement connue de production de tels vaccins. Des indicateurs isotopiques sont utilisés pour étudier le mouvement et le métabolisme des substances nutritives chez les animaux d'élevage et sont particulièrement précieux pour l'étude des oligoéléments essentiels. L'avantage que seuls possèdent les indicateurs isotopiques de permettre la détection de quantités infimes de produits chimiques est la raison d'être d'un nouveau programme de recherches sur les résidus de pesticides nuisibles dans les aliments d'origine végétale et animale. L’effet stérilisant et germicide des rayonnements possède une valeur irremplaçable pour la prévention ou le retard de l'altération d'un grand nombre de denrées alimentaires. La conservation par irradiation peut, par exemple, être utilisée, même après emballage, pour les denrées périssables ne supportant ni la cuisson ni la congélation. Afin de promouvoir sur le plan international l'application des sciences nucléaires dans l'alimentation et l'agriculture, la Division mixte FAO/AIEA de l'énergie atomique dans l'alimentation et l'agriculture exécute un programme de travail commun, approuvé par les deux organisations. Pour l'exécution des travaux dans tous les domaines, la Division a très souvent recours à la formule