The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Jack R Harkema - One of the best experts on this subject based on the ideXlab platform.
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endotoxin potentiates ozone induced mucous cell metaplasia in rat nasal epithelium
Toxicology and Applied Pharmacology, 1998Co-Authors: Michelle V. Fanucchi, Jon A Hotchkiss, Jack R HarkemaAbstract:Abstract People are exposed to a combination of environmental Pollutants throughout their lives. Repeated exposures of one Common Pollutant, ozone, have been reported to cause the development of mucous cell metaplasia in the nasal transitional epithelium (NTE) of rats. The present study was designed to test the hypothesis that exposure to bacterial endotoxin, another toxicant ubiquitous to the environment, potentiates this metaplastic response in rat NTE. Rats were exposed to 0 or 0.5 ppm ozone 8 h/day for 3 days. After ozone exposure, rats were intranasally instilled with saline containing 0 or 100 μg/ml endotoxin once daily for 2 days. Rats were killed 6 h or 3 days after the last intranasal instillation. Nasal tissue was processed for light microscopy and image analysis, or for isolation of total RNA. Mucous cell metaplasia was not detected in air/endotoxin-exposed rats, was observed in ozone/saline-exposed rats, and was most severe in ozone/endotoxin-exposed rats. At 6 h after instillation, amounts of intraepithelial mucosubstances (IM) were 4-fold greater in NTE of ozone/endotoxin-exposed rats as compared to controls. These IM levels were similar to those of ozone/saline-exposed rats. Mucin-specific mRNA (rMuc-5AC) levels were elevated in all treatment groups at this timepoint. At 3 days after instillation, amounts of IM in ozone/endotoxin-exposed rats were 10-fold greater than in controls and 5-fold greater than in ozone/saline-exposed rats. rMuc-5AC mRNA levels remained elevated in the ozone/endotoxin-exposed rats. Despite the fact that bacterial endotoxin alone does not cause a phenotypic change in rat NTE, it can augment the mucous cell metaplasia induced by a previous exposure to ozone.
Shahid Hussain - One of the best experts on this subject based on the ideXlab platform.
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Microwave plasma removal of sulphur hexafluoride
Journal of hazardous materials, 2008Co-Authors: Marilena T. Radoiu, Shahid HussainAbstract:Sulphur hexafluoride (SF(6)) gas is a Common Pollutant emitted during the plasma etching of thin films and plasma cleaning chemical vapor deposition (CVD) production processes used in the semiconductor industry. In this paper a method using microwave (2.45GHz frequency) plasmas sustained at atmospheric pressure for the abatement of SF(6) is investigated experimentally for various gas mixture constituents and operating conditions, with respect to its ability to decompose SF(6) to less harmful molecules. The destruction and removal efficiencies (DRE) of plasma abatement of SF(6) at concentrations between 1.7 and 5% in nitrogen in the presence of water vapor were studied as a function of the total gas flow rate and microwave power. Water vapor proved to be an effective source of free radical species that reacts with the radicals and ions resulting from SF(6) fragmentation in the plasma and also, it proved to reduce the process by-products. It was measured that approximately 25% of the initial SF(6) is converted to SO(2). Destruction and removal efficiencies of SF(6) up to 99.9% have been achieved.
Venkateswarlu Chimmiri - One of the best experts on this subject based on the ideXlab platform.
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Critical review of abatement of ammonia from wastewater
Journal of Molecular Liquids, 2018Co-Authors: Rama Rao Karri, J.n. Sahu, Venkateswarlu ChimmiriAbstract:Abstract Ammonia being a most Common Pollutant found in water streams. As the presence of ammonia and its associated compounds in effluent wastewater discharged to water bodies pose a severe threat to aquatic life and human health by consumption of seafood, removal of Pollutants from wastewater is of paramount importance. A number of conventional methods have been adopted for the removal of these Pollutants with varying degree of success. This article reviews the technologies implemented for removal of ammonia and its associated compounds from wastewater based on the physicochemical methods and biochemical treatment methods like biological treatment, membrane filtration, ion exchange, chemical precipitation, adsorption and some other technologies such as photocatalytic oxidation, aeration, and air stripping. Merits and demerits of each of the techniques were discussed. This paper also reviews the impact of process parameters on the ammonia removal efficiency is thoroughly discussed.
Michelle V. Fanucchi - One of the best experts on this subject based on the ideXlab platform.
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endotoxin potentiates ozone induced mucous cell metaplasia in rat nasal epithelium
Toxicology and Applied Pharmacology, 1998Co-Authors: Michelle V. Fanucchi, Jon A Hotchkiss, Jack R HarkemaAbstract:Abstract People are exposed to a combination of environmental Pollutants throughout their lives. Repeated exposures of one Common Pollutant, ozone, have been reported to cause the development of mucous cell metaplasia in the nasal transitional epithelium (NTE) of rats. The present study was designed to test the hypothesis that exposure to bacterial endotoxin, another toxicant ubiquitous to the environment, potentiates this metaplastic response in rat NTE. Rats were exposed to 0 or 0.5 ppm ozone 8 h/day for 3 days. After ozone exposure, rats were intranasally instilled with saline containing 0 or 100 μg/ml endotoxin once daily for 2 days. Rats were killed 6 h or 3 days after the last intranasal instillation. Nasal tissue was processed for light microscopy and image analysis, or for isolation of total RNA. Mucous cell metaplasia was not detected in air/endotoxin-exposed rats, was observed in ozone/saline-exposed rats, and was most severe in ozone/endotoxin-exposed rats. At 6 h after instillation, amounts of intraepithelial mucosubstances (IM) were 4-fold greater in NTE of ozone/endotoxin-exposed rats as compared to controls. These IM levels were similar to those of ozone/saline-exposed rats. Mucin-specific mRNA (rMuc-5AC) levels were elevated in all treatment groups at this timepoint. At 3 days after instillation, amounts of IM in ozone/endotoxin-exposed rats were 10-fold greater than in controls and 5-fold greater than in ozone/saline-exposed rats. rMuc-5AC mRNA levels remained elevated in the ozone/endotoxin-exposed rats. Despite the fact that bacterial endotoxin alone does not cause a phenotypic change in rat NTE, it can augment the mucous cell metaplasia induced by a previous exposure to ozone.
Curtis P. Berlinguette - One of the best experts on this subject based on the ideXlab platform.
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A comparison of several nanoscale photocatalysts in the degradation of a Common Pollutant using LEDs and conventional UV light.
Water research, 2009Co-Authors: Jyoti P. Ghosh, Ruohong Sui, Cooper H. Langford, Gopal Achari, Curtis P. BerlinguetteAbstract:A comparative study on the photocatalytic activities of four different catalysts, P-25 TiO(2), TiO(2) nanofibers, tin-doped TiO(2) nanofibers under UV light irradiation at 350 nm, and coumarin (C-343) coated TiO(2) nanofibers at 436 nm light emitting diodes (LED) is reported. Catalysts performance has been compared based on their reflectance spectrum and activity. A Common water contaminant 4-chlorophenol was used as a substrate to compare the activity of the different catalysts under both direct and dye sensitized conditions. Results indicated that amongst the four different catalysts the activity of P-25 was the highest. However the activity of C-343 coated TiO(2) nanofibers in the LED (436 nm) based reactor was competitive. Identification of reaction intermediates implied that the reaction pathways under UV (band gap) and visible (dye sensitized) irradiation were different. Nonetheless, ring opening took place in all reactions with both maleic and dihydroxymaleic have been identified as intermediates. The study indicates that ordered arrays of TiO(2) irradiated by panels of arrays of low cost high intensity LEDs might be used for the design of reactors. The near monochromaticity, long life, and operation under direct currents are advantages of using LEDs.