The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Philip Demokritou - One of the best experts on this subject based on the ideXlab platform.
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synthesis and physicochemical transformations of size sorted graphene oxide during simulated digestion and its Toxicological Assessment against an in vitro model of the human intestinal epithelium
Small, 2020Co-Authors: Dimitrios Bitounis, Dorsa Parviz, Xiaoqiong Cao, Carlo A. Amadei, Chad D. Vecitis, Elsie M. Sunderland, Brian D. Thrall, Mingliang Fang, Michael S. Strano, Philip DemokritouAbstract:In the last decade, along with the increasing use of graphene oxide (GO) in various applications, there is also considerable interest in understanding its effects on human health. Only a few experimental approaches can simulate common routes of exposure, such as ingestion, due to the inherent complexity of the digestive tract. This study presents the synthesis of size-sorted GO of sub-micrometer- or micrometer-sized lateral dimensions, its physicochemical transformations across mouth, gastric, and small intestinal simulated digestions, and its Toxicological Assessment against a physiologically relevant, in vitro cellular model of the human intestinal epithelium. Results from real-time characterization of the simulated digestas of the gastrointestinal tract using multi-angle laser diffraction and field-emission scanning electron microscopy show that GO agglomerates in the gastric and small intestinal phase. Extensive morphological changes, such as folding, are also observed on GO following simulated digestion. Furthermore, X-ray photoelectron spectroscopy reveals that GO presents covalently bound N-containing groups on its surface. It is shown that the GO employed in this study undergoes reduction. Toxicological Assessment of the GO small intestinal digesta over 24 h does not point to acute cytotoxicity, and examination of the intestinal epithelium under electron microscopy does not reveal histological alterations. Both sub-micrometer- and micrometer-sized GO variants elicit a 20% statistically significant increase in reactive oxygen species generation compared to the untreated control after a 6 h exposure.
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Synthesis and Physicochemical Transformations of Size‐Sorted Graphene Oxide during Simulated Digestion and Its Toxicological Assessment against an In Vitro Model of the Human Intestinal Epithelium
Small (Weinheim an der Bergstrasse Germany), 2020Co-Authors: Dimitrios Bitounis, Dorsa Parviz, Xiaoqiong Cao, Carlo A. Amadei, Chad D. Vecitis, Elsie M. Sunderland, Brian D. Thrall, Mingliang Fang, Michael S. Strano, Philip DemokritouAbstract:In the last decade, along with the increasing use of graphene oxide (GO) in various applications, there is also considerable interest in understanding its effects on human health. Only a few experimental approaches can simulate common routes of exposure, such as ingestion, due to the inherent complexity of the digestive tract. This study presents the synthesis of size-sorted GO of sub-micrometer- or micrometer-sized lateral dimensions, its physicochemical transformations across mouth, gastric, and small intestinal simulated digestions, and its Toxicological Assessment against a physiologically relevant, in vitro cellular model of the human intestinal epithelium. Results from real-time characterization of the simulated digestas of the gastrointestinal tract using multi-angle laser diffraction and field-emission scanning electron microscopy show that GO agglomerates in the gastric and small intestinal phase. Extensive morphological changes, such as folding, are also observed on GO following simulated digestion. Furthermore, X-ray photoelectron spectroscopy reveals that GO presents covalently bound N-containing groups on its surface. It is shown that the GO employed in this study undergoes reduction. Toxicological Assessment of the GO small intestinal digesta over 24 h does not point to acute cytotoxicity, and examination of the intestinal epithelium under electron microscopy does not reveal histological alterations. Both sub-micrometer- and micrometer-sized GO variants elicit a 20% statistically significant increase in reactive oxygen species generation compared to the untreated control after a 6 h exposure.
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development and characterization of electronic cigarette exposure generation system ecig egs for the physico chemical and Toxicological Assessment of electronic cigarette emissions
Inhalation Toxicology, 2016Co-Authors: Jiayuan Zhao, Georgios Pyrgiotakis, Philip DemokritouAbstract:AbstractElectronic cigarettes (e-cig) have been introduced as a nicotine replacement therapy and have gained increasing attention and popularity. However, while findings on possible Toxicological implications continue to grow, major knowledge gaps on both the complex chemistry of the exposure and toxicity exist, prohibiting public health assessors from assessing risks. Here, a versatile electronic cigarette exposure generation system (Ecig-EGS) has been developed and characterized. Ecig-EGS allows generation of real world e-cig emission profiles under controlled operational conditions, real time monitoring and time-integrated particle/gas sampling for physico-chemical characterization, and Toxicological Assessment (both in vitro and in vivo). The platform is highly versatile and can be used with all e-cig types. It enables generation of precisely controlled e-cig exposure while critical operational parameters and environmental mixing conditions can be adjusted in a systematic manner to assess their impact...
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Development and characterization of electronic-cigarette exposure generation system (Ecig-EGS) for the physico-chemical and Toxicological Assessment of electronic cigarette emissions.
Inhalation toxicology, 2016Co-Authors: Jiayuan Zhao, Georgios Pyrgiotakis, Philip DemokritouAbstract:Electronic cigarettes (e-cig) have been introduced as a nicotine replacement therapy and have gained increasing attention and popularity. However, while findings on possible Toxicological implications continue to grow, major knowledge gaps on both the complex chemistry of the exposure and toxicity exist, prohibiting public health assessors from assessing risks. Here, a versatile electronic cigarette exposure generation system (Ecig-EGS) has been developed and characterized. Ecig-EGS allows generation of real world e-cig emission profiles under controlled operational conditions, real time monitoring and time-integrated particle/gas sampling for physico-chemical characterization, and Toxicological Assessment (both in vitro and in vivo). The platform is highly versatile and can be used with all e-cig types. It enables generation of precisely controlled e-cig exposure while critical operational parameters and environmental mixing conditions can be adjusted in a systematic manner to assess their impact on complex chemistry and toxicity of emissions. Results proved the versatility and reproducibility of Ecig-EGS. E-cig emission was found to contain 106-107 particles/cm3 with the mode diameter around 200 nm, under air change rate of 60/h. Elevated CO2 and volatile organic specie generation was also observed. Furthermore, environmental mixing conditions also influenced e-cig emission profile. The versatility of Ecig-EGS will enable linking of operational and environmental parameters with exposure chemistry and toxicology and help in assessing health risks.
Guillermina Hernandez Raquet - One of the best experts on this subject based on the ideXlab platform.
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Chemical and Toxicological Assessment of a full-scale biosolid compost.
Environmental Toxicology and Chemistry, 2012Co-Authors: Dominique Patureau, Mathieu Muller, Sonia Dagnino, Claire Lhoutellier, Jean-philippe Delgenès, Patrick Balaguer, Nadine Delgenès, Guillermina Hernandez RaquetAbstract:The impact of a full-scale biosolid composting plant on the fate of a broad range of priority organic pollutants was investigated. Chemical analysis was performed at different steps of the process during two seasons. Simultaneously, the Toxicological quality was assessed using estrogen α-, dioxin-, and pregnane X-receptor reporter cell lines. Mass-balance calculation highlighted the removal of easily degradable pollutants during composting. The important variations observed for each compound and for the two seasons might be explained by pollutant-fate dependency on process parameters like temperature. The final compost displayed low pregnane X activity but high estrogenic activity. The dioxin-like activity stayed constant through the process. The chemical and Toxicological results highlight the importance of combining both approaches to accurately assess the compost quality. Such compilation of data on full-scale processes may be also very helpful for the environmental risk Assessment of new organic waste disposal practices. Environ. Toxicol. Chem. 2012; 31: 2748–2756. © 2012 SETAC
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Chemical and Toxicological Assessment of a full-scale biosolid compost
Environmental Toxicology and Chemistry, 2012Co-Authors: Dominique Patureau, Nadine Cathala-delgenès, Mathieu Muller, Sonia Dagnino, Claire Lhoutellier, Jean-philippe Delgenès, Patrick Balaguer, Guillermina Hernandez RaquetAbstract:The impact of a full-scale biosolid composting plant on the fate of a broad range of priority organic pollutants was investigated. Chemical analysis was performed at different steps of the process during two seasons. Simultaneously, the Toxicological quality was assessed using estrogen alpha-, dioxin-, and pregnane X-receptor reporter cell lines. Mass-balance calculation highlighted the removal of easily degradable pollutants during composting. The important variations observed for each compound and for the two seasons might be explained by pollutant-fate dependency on process parameters like temperature. The final compost displayed low pregnane X activity but high estrogenic activity. The dioxin-like activity stayed constant through the process. The chemical and Toxicological results highlight the importance of combining both approaches to accurately assess the compost quality. Such compilation of data on full-scale processes may be also very helpful for the environmental risk Assessment of new organic waste disposal practices.
Dimitrios Bitounis - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and Physicochemical Transformations of Size‐Sorted Graphene Oxide during Simulated Digestion and Its Toxicological Assessment against an In Vitro Model of the Human Intestinal Epithelium
Small (Weinheim an der Bergstrasse Germany), 2020Co-Authors: Dimitrios Bitounis, Dorsa Parviz, Xiaoqiong Cao, Carlo A. Amadei, Chad D. Vecitis, Elsie M. Sunderland, Brian D. Thrall, Mingliang Fang, Michael S. Strano, Philip DemokritouAbstract:In the last decade, along with the increasing use of graphene oxide (GO) in various applications, there is also considerable interest in understanding its effects on human health. Only a few experimental approaches can simulate common routes of exposure, such as ingestion, due to the inherent complexity of the digestive tract. This study presents the synthesis of size-sorted GO of sub-micrometer- or micrometer-sized lateral dimensions, its physicochemical transformations across mouth, gastric, and small intestinal simulated digestions, and its Toxicological Assessment against a physiologically relevant, in vitro cellular model of the human intestinal epithelium. Results from real-time characterization of the simulated digestas of the gastrointestinal tract using multi-angle laser diffraction and field-emission scanning electron microscopy show that GO agglomerates in the gastric and small intestinal phase. Extensive morphological changes, such as folding, are also observed on GO following simulated digestion. Furthermore, X-ray photoelectron spectroscopy reveals that GO presents covalently bound N-containing groups on its surface. It is shown that the GO employed in this study undergoes reduction. Toxicological Assessment of the GO small intestinal digesta over 24 h does not point to acute cytotoxicity, and examination of the intestinal epithelium under electron microscopy does not reveal histological alterations. Both sub-micrometer- and micrometer-sized GO variants elicit a 20% statistically significant increase in reactive oxygen species generation compared to the untreated control after a 6 h exposure.
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synthesis and physicochemical transformations of size sorted graphene oxide during simulated digestion and its Toxicological Assessment against an in vitro model of the human intestinal epithelium
Small, 2020Co-Authors: Dimitrios Bitounis, Dorsa Parviz, Xiaoqiong Cao, Carlo A. Amadei, Chad D. Vecitis, Elsie M. Sunderland, Brian D. Thrall, Mingliang Fang, Michael S. Strano, Philip DemokritouAbstract:In the last decade, along with the increasing use of graphene oxide (GO) in various applications, there is also considerable interest in understanding its effects on human health. Only a few experimental approaches can simulate common routes of exposure, such as ingestion, due to the inherent complexity of the digestive tract. This study presents the synthesis of size-sorted GO of sub-micrometer- or micrometer-sized lateral dimensions, its physicochemical transformations across mouth, gastric, and small intestinal simulated digestions, and its Toxicological Assessment against a physiologically relevant, in vitro cellular model of the human intestinal epithelium. Results from real-time characterization of the simulated digestas of the gastrointestinal tract using multi-angle laser diffraction and field-emission scanning electron microscopy show that GO agglomerates in the gastric and small intestinal phase. Extensive morphological changes, such as folding, are also observed on GO following simulated digestion. Furthermore, X-ray photoelectron spectroscopy reveals that GO presents covalently bound N-containing groups on its surface. It is shown that the GO employed in this study undergoes reduction. Toxicological Assessment of the GO small intestinal digesta over 24 h does not point to acute cytotoxicity, and examination of the intestinal epithelium under electron microscopy does not reveal histological alterations. Both sub-micrometer- and micrometer-sized GO variants elicit a 20% statistically significant increase in reactive oxygen species generation compared to the untreated control after a 6 h exposure.
Dominique Patureau - One of the best experts on this subject based on the ideXlab platform.
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Chemical and Toxicological Assessment of a full-scale biosolid compost.
Environmental Toxicology and Chemistry, 2012Co-Authors: Dominique Patureau, Mathieu Muller, Sonia Dagnino, Claire Lhoutellier, Jean-philippe Delgenès, Patrick Balaguer, Nadine Delgenès, Guillermina Hernandez RaquetAbstract:The impact of a full-scale biosolid composting plant on the fate of a broad range of priority organic pollutants was investigated. Chemical analysis was performed at different steps of the process during two seasons. Simultaneously, the Toxicological quality was assessed using estrogen α-, dioxin-, and pregnane X-receptor reporter cell lines. Mass-balance calculation highlighted the removal of easily degradable pollutants during composting. The important variations observed for each compound and for the two seasons might be explained by pollutant-fate dependency on process parameters like temperature. The final compost displayed low pregnane X activity but high estrogenic activity. The dioxin-like activity stayed constant through the process. The chemical and Toxicological results highlight the importance of combining both approaches to accurately assess the compost quality. Such compilation of data on full-scale processes may be also very helpful for the environmental risk Assessment of new organic waste disposal practices. Environ. Toxicol. Chem. 2012; 31: 2748–2756. © 2012 SETAC
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Chemical and Toxicological Assessment of a full-scale biosolid compost
Environmental Toxicology and Chemistry, 2012Co-Authors: Dominique Patureau, Nadine Cathala-delgenès, Mathieu Muller, Sonia Dagnino, Claire Lhoutellier, Jean-philippe Delgenès, Patrick Balaguer, Guillermina Hernandez RaquetAbstract:The impact of a full-scale biosolid composting plant on the fate of a broad range of priority organic pollutants was investigated. Chemical analysis was performed at different steps of the process during two seasons. Simultaneously, the Toxicological quality was assessed using estrogen alpha-, dioxin-, and pregnane X-receptor reporter cell lines. Mass-balance calculation highlighted the removal of easily degradable pollutants during composting. The important variations observed for each compound and for the two seasons might be explained by pollutant-fate dependency on process parameters like temperature. The final compost displayed low pregnane X activity but high estrogenic activity. The dioxin-like activity stayed constant through the process. The chemical and Toxicological results highlight the importance of combining both approaches to accurately assess the compost quality. Such compilation of data on full-scale processes may be also very helpful for the environmental risk Assessment of new organic waste disposal practices.
Jacqueline Wiesner - One of the best experts on this subject based on the ideXlab platform.
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thujone and thujone containing herbal medicinal and botanical products Toxicological Assessment
Regulatory Toxicology and Pharmacology, 2013Co-Authors: Olavi Pelkonen, Khaled Abass, Jacqueline WiesnerAbstract:Abstract Thujone, a major component of the notoriously famous absinthe drink, is neurotoxic, although the current view rather downgrades its risk to humans. In animal studies, thujone inhibits the gamma-aminobutyric acid A (GABAA) receptor causing excitation and convulsions in a dose-dependent manner, although there are uncertainties about the doses required in humans. Toxicity of thujone has been extensively studied. Neurotoxicity is the principal toxic outcome in acute and chronic studies. There is some equivocal evidence of carcinogenicity in rats. Metabolism of thujone has been elucidated both in vitro and in vivo in several species and in vitro in human liver preparations. CYP2A6 is the principal metabolic enzyme, followed by CYP3A4 and, to a lesser extent, CYP2B6. CYP-associated metabolism may give rise to some potential pharmacogenetic and metabolic interaction consequences. Although the data base for determining exposure limits is of variable usefulness, the best estimates for allowable daily intakes via herbal preparations and diet are of the order of 3–7 mg/day. There are still important gaps in the knowledge required to assess thujone toxicity, the most important ones being human dose-concentration-effect relationships including the elucidation of bioavailability, and the actual Toxicological consequences of potential pharmacogenetic variations and environmental factors.
