The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Simon C George - One of the best experts on this subject based on the ideXlab platform.
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biomarker signatures of upper cretaceous latrobe group hydrocarbon source rocks gippsland basin australia distribution and palaeoenvironment significance of aliphatic Hydrocarbons
International Journal of Coal Geology, 2018Co-Authors: Lian Jiang, Simon C GeorgeAbstract:Abstract Upper Cretaceous (Maastrichtian and Campanian) hydrocarbon source rocks from the Latrobe Group, Gippsland Basin (Australia) have been analysed using gas chromatography–mass spectrometry (GC–MS) in order to understand their geochemical characteristics and to reconstruct palaeovegetation and palaeoclimate changes. n-Alkanes ranging from C10 to C37 dominate the aliphatic Hydrocarbons in the rock extracts. Both the carbon preference index and the odd-to-even predominance values of n-alkanes are higher than 1.0, suggesting an input from terrigenous higher plants. Low wax indices (mostly 3.0), a low gammacerane index (
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Hydrocarbons preserved in a 2 7 ga outcrop sample from the fortescue group pilbara craton western australia
Geobiology, 2015Co-Authors: Simon C George, Yosuke Hoshino, David T Flannery, Malcolm R WalterAbstract:The Hydrocarbons preserved in an Archean rock were extracted, and their composition and distribution in consecutive slices from the outside to the inside of the rock were examined. The 2.7 Ga rock was collected from the Fortescue Group in the Pilbara region, Western Australia. The bitumen I (solvent-extracted rock) and bitumen II (solvent-extracted hydrochloric acid-treated rock) fractions have different hydrocarbon compositions. Bitumen I contains only trace amounts of aliphatic Hydrocarbons and virtually no aromatic Hydrocarbons. In contrast, bitumen II contains abundant aliphatic and aromatic Hydrocarbons. The difference seems to reflect the weathering history and preservational environment of the investigated rock. Aliphatic Hydrocarbons in bitumen I are considered to be mainly from later hydrocarbon inputs, after initial deposition and burial, and are therefore not indigenous. The lack of aromatic Hydrocarbons in bitumen I suggests a severe weathering environment since uplift and exposure of the rock at the Earth's surface in the Cenozoic. On the other hand, the high abundance of aromatic Hydrocarbons in bitumen II suggests that bitumen II Hydrocarbons have been physically isolated from removal by their encapsulation within carbonate minerals. The richness of aromatic Hydrocarbons and the relative scarcity of aliphatic Hydrocarbons may reflect the original compositions of organic materials biosynthesised in ancient organisms in the Archean era, or the high thermal maturity of the rock. Cyanobacterial biomarkers were observed in the surficial slices of the rock, which may indicate that endolithic cyanobacteria inhabited the surface outcrop. The distribution of aliphatic and aromatic Hydrocarbons implies a high thermal maturity, which is consistent with the lack of any specific biomarkers, such as hopanes and steranes, and the prehnite-pumpellyite facies metamorphic grade.
N N Bakhshi - One of the best experts on this subject based on the ideXlab platform.
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performance of aluminophosphate molecular sieve catalysts for the production of Hydrocarbons from wood derived and vegetable oils
Energy & Fuels, 1995Co-Authors: Sai P R Katikaneni, John Adjaye, N N BakhshiAbstract:A wood-derived oil and canola oil (termed bio-oils) were converted catalytically over aluminophosphate catalysts, namely, SAPO-5, SAPO-11 and MgAPO-36. The catalysts were prepared and then characterized using BET surface area, pore size, X-ray powder diffraction, ammonia temperature-programmed adsorption and desorption, and NMR measurements. The test runs were performed in a fixed bed microreactor which was operated at 3.6 weight hourly space velocity (WHSV) and temperature ranges of 330-410 °C for wood-derived oil (WDO) and 375-550 °C for canola oil. The objective was to investigate the potential for the production of both liquid and gaseous hydrocarbon products from the conversion of bio-oils using aluminophosphate catalysts. With WDO, between 12 and 23 wt % of an organic liquid product (OLP) was obtained which contained an optimum of 61.5, 56.8, and 57.0 wt % (for SAPO-5, SAPO-11, and MgAPO-36, respectively) liquid Hydrocarbons. All three catalysts were selective for both aromatic and aliphatic Hydrocarbons in comparable proportions. With canola oil, between 12 and 48 wt % OLP was obtained. The optimum yields of Hydrocarbons were 65.8, 51.1, and 45.3 wt % of OLP for SAPO-5, SAPO-11, and MgAPO-36, respectively. SAPO-5 and SAPO-11 were highly selective for aromatic Hydrocarbons. On the other hand, MgAPO-36 produced high fractions of aliphatic Hydrocarbons at temperatures below 450 °C and high aromatic Hydrocarbons at temperatures above 450 °C. Furthermore, 8-17 and 5-63 wt % gas was produced with WDO and canola oil, respectively. The gas composition consisted mostly of C 1 -C 4 Hydrocarbons. The results showed that the conversion of bio-oils to Hydrocarbons with aluminophosphate catalyst was low as compared to HZSM-5 catalyst. However, some potential exists for the production of Hydrocarbons such as benzene (with WDO) and toluene and xylenes (with canola oil) as well as important gaseous Hydrocarbons such as ethylene, propylene, and n-butane.
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performance of aluminophosphate molecular sieve catalysts for the production of Hydrocarbons from wood derived and vegetable oils
Energy & Fuels, 1995Co-Authors: Sai P R Katikaneni, John Adjaye, N N BakhshiAbstract:A wood-derived oil and canola oil (termed bio-oils) were converted catalytically over aluminophosphate catalysts, namely, SAPO-5, SAPO-11 and MgAPO-36. The catalysts were prepared and then characterized using BET surface area, pore size, X-ray powder diffraction, ammonia temperature-programmed adsorption and desorption, and NMR measurements. The test runs were performed in a fixed bed microreactor which was operated at 3.6 weight hourly space velocity (WHSV) and temperature ranges of 330-410 °C for wood-derived oil (WDO) and 375-550 °C for canola oil. The objective was to investigate the potential for the production of both liquid and gaseous hydrocarbon products from the conversion of bio-oils using aluminophosphate catalysts. With WDO, between 12 and 23 wt % of an organic liquid product (OLP) was obtained which contained an optimum of 61.5, 56.8, and 57.0 wt % (for SAPO-5, SAPO-11, and MgAPO-36, respectively) liquid Hydrocarbons. All three catalysts were selective for both aromatic and aliphatic Hydrocarbons in comparable proportions. With canola oil, between 12 and 48 wt % OLP was obtained. The optimum yields of Hydrocarbons were 65.8, 51.1, and 45.3 wt % of OLP for SAPO-5, SAPO-11, and MgAPO-36, respectively. SAPO-5 and SAPO-11 were highly selective for aromatic Hydrocarbons. On the other hand, MgAPO-36 produced high fractions of aliphatic Hydrocarbons at temperatures below 450 °C and high aromatic Hydrocarbons at temperatures above 450 °C. Furthermore, 8-17 and 5-63 wt % gas was produced with WDO and canola oil, respectively. The gas composition consisted mostly of C 1 -C 4 Hydrocarbons. The results showed that the conversion of bio-oils to Hydrocarbons with aluminophosphate catalyst was low as compared to HZSM-5 catalyst. However, some potential exists for the production of Hydrocarbons such as benzene (with WDO) and toluene and xylenes (with canola oil) as well as important gaseous Hydrocarbons such as ethylene, propylene, and n-butane.
Richard T Di Giulio - One of the best experts on this subject based on the ideXlab platform.
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the role of the aryl hydrocarbon receptor pathway in mediating synergistic developmental toxicity of polycyclic aromatic Hydrocarbons to zebrafish
Toxicological Sciences, 2006Co-Authors: Sonya M Billiard, Alicia R Timmelaragy, Deena Wassenberg, Crystal J Cockman, Richard T Di GiulioAbstract:Planar halogenated aromatic Hydrocarbons (pHAHs), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), show strong binding affinity for the aryl hydrocarbon receptor (AHR) and are potent inducers of cytochrome P4501A (CYP1A). It is widely accepted that dioxin toxicity is largely AHR mediated; however, the role of CYP1A activity in causing that toxicity is less clear. Another class of AHR agonists of increasing concern because of their known toxicity and ubiquity in the environment is the polycyclic aromatic Hydrocarbons (PAHs). Like dioxin, some PAHs also cause toxicity to early life stages of vertebrates. Symptoms include increased cardiovascular dysfunction, pericardial and yolk sac edemas, subcutaneous hemorrhages, craniofacial deformities, reduced growth, and increased mortality rates. Although developmental effects are comparable between these two types of AHR agonists, the roles of both the AHR and CYP1A activity in PAH toxicity are unknown. As observed in previous studies with killifish (Fundulus heteroclitus), we demonstrate here that coexposure of zebrafish (Danio rerio) embryos to the PAH-type AHR agonist beta-naphthoflavone (BNF) and the CYP1A inhibitor alpha-naphthoflavone (ANF) significantly enhanced toxicity above that observed for single-compound exposures. In order to elucidate the role of the AHR pathway in mediating synergistic toxicity of PAH mixtures to early life stages, we used a morpholino approach to knock down expression of zebrafish AHR2 and CYP1A proteins during development. We observed that while knock down of AHR2 reduces cardiac toxicity of BNF combined with ANF to zebrafish embryos, CYP1A knockdown markedly enhanced toxicity of BNF alone and BNF + ANF coexposures. These data support earlier chemical inducer/inhibitor studies and also suggest that mechanisms underlying developmental toxicity of PAH-type AHR agonists are different from those of pHAHs. Identifying the pathways involved in PAH toxicity will provide for more robust, mechanistic-based tools for risk assessment of single compounds and complex environmental mixtures.
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the role of the aryl hydrocarbon receptor pathway in mediating synergistic developmental toxicity of polycyclic aromatic Hydrocarbons to zebrafish
Toxicological Sciences, 2006Co-Authors: Sonya M Billiard, Alicia R Timmelaragy, Deena Wassenberg, Crystal J Cockman, Richard T Di GiulioAbstract:Planar halogenated aromatic Hydrocarbons (pHAHs), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), show strong binding affinity for the aryl hydrocarbon receptor (AHR) and are potent inducers of cytochrome P4501A (CYP1A). It is widely accepted that dioxin toxicity is largely AHR mediated; however, the role of CYP1Aactivityincausingthattoxicityislessclear.Anotherclassof AHR agonistsofincreasing concernbecause oftheirknowntoxicity and ubiquity in the environment is the polycyclic aromatic Hydrocarbons(PAHs).Likedioxin,somePAHsalsocausetoxicitytoearly life stages of vertebrates. Symptoms include increased cardiovascular dysfunction, pericardial and yolk sac edemas, subcutaneous hemorrhages, craniofacial deformities, reduced growth, and increased mortality rates. Although developmental effects are comparable between these two types of AHR agonists, the roles of both the AHR and CYP1A activity in PAH toxicity are unknown. As observed in previous studies with killifish (Fundulus heteroclitus), we demonstrate here that coexposure of zebrafish (Danio rerio) embryos to the PAH-type AHR agonist b-naphthoflavone (BNF) and the CYP1A inhibitor a-naphthoflavone (ANF) significantly enhanced toxicity above that observed for single-compound exposures. In order to elucidate the role of the AHR pathway in mediating synergistic toxicity of PAH mixtures to early life stages, we used a morpholino approach to knock down expression of zebrafish AHR2 and CYP1A proteins during development. We observed that while knock down of AHR2 reduces cardiac toxicity of BNF combined with ANF to zebrafish embryos, CYP1A knockdown markedly enhanced toxicity of BNF alone and BNF + ANF coexposures. These data support earlier chemical inducer/inhibitor studies and also suggest that mechanisms underlying developmental toxicity of PAH-type AHR agonists are different from those of pHAHs. Identifying the pathways involved in PAH toxicity will provide for more robust, mechanistic-based tools for risk assessment
Sai P R Katikaneni - One of the best experts on this subject based on the ideXlab platform.
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performance of aluminophosphate molecular sieve catalysts for the production of Hydrocarbons from wood derived and vegetable oils
Energy & Fuels, 1995Co-Authors: Sai P R Katikaneni, John Adjaye, N N BakhshiAbstract:A wood-derived oil and canola oil (termed bio-oils) were converted catalytically over aluminophosphate catalysts, namely, SAPO-5, SAPO-11 and MgAPO-36. The catalysts were prepared and then characterized using BET surface area, pore size, X-ray powder diffraction, ammonia temperature-programmed adsorption and desorption, and NMR measurements. The test runs were performed in a fixed bed microreactor which was operated at 3.6 weight hourly space velocity (WHSV) and temperature ranges of 330-410 °C for wood-derived oil (WDO) and 375-550 °C for canola oil. The objective was to investigate the potential for the production of both liquid and gaseous hydrocarbon products from the conversion of bio-oils using aluminophosphate catalysts. With WDO, between 12 and 23 wt % of an organic liquid product (OLP) was obtained which contained an optimum of 61.5, 56.8, and 57.0 wt % (for SAPO-5, SAPO-11, and MgAPO-36, respectively) liquid Hydrocarbons. All three catalysts were selective for both aromatic and aliphatic Hydrocarbons in comparable proportions. With canola oil, between 12 and 48 wt % OLP was obtained. The optimum yields of Hydrocarbons were 65.8, 51.1, and 45.3 wt % of OLP for SAPO-5, SAPO-11, and MgAPO-36, respectively. SAPO-5 and SAPO-11 were highly selective for aromatic Hydrocarbons. On the other hand, MgAPO-36 produced high fractions of aliphatic Hydrocarbons at temperatures below 450 °C and high aromatic Hydrocarbons at temperatures above 450 °C. Furthermore, 8-17 and 5-63 wt % gas was produced with WDO and canola oil, respectively. The gas composition consisted mostly of C 1 -C 4 Hydrocarbons. The results showed that the conversion of bio-oils to Hydrocarbons with aluminophosphate catalyst was low as compared to HZSM-5 catalyst. However, some potential exists for the production of Hydrocarbons such as benzene (with WDO) and toluene and xylenes (with canola oil) as well as important gaseous Hydrocarbons such as ethylene, propylene, and n-butane.
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performance of aluminophosphate molecular sieve catalysts for the production of Hydrocarbons from wood derived and vegetable oils
Energy & Fuels, 1995Co-Authors: Sai P R Katikaneni, John Adjaye, N N BakhshiAbstract:A wood-derived oil and canola oil (termed bio-oils) were converted catalytically over aluminophosphate catalysts, namely, SAPO-5, SAPO-11 and MgAPO-36. The catalysts were prepared and then characterized using BET surface area, pore size, X-ray powder diffraction, ammonia temperature-programmed adsorption and desorption, and NMR measurements. The test runs were performed in a fixed bed microreactor which was operated at 3.6 weight hourly space velocity (WHSV) and temperature ranges of 330-410 °C for wood-derived oil (WDO) and 375-550 °C for canola oil. The objective was to investigate the potential for the production of both liquid and gaseous hydrocarbon products from the conversion of bio-oils using aluminophosphate catalysts. With WDO, between 12 and 23 wt % of an organic liquid product (OLP) was obtained which contained an optimum of 61.5, 56.8, and 57.0 wt % (for SAPO-5, SAPO-11, and MgAPO-36, respectively) liquid Hydrocarbons. All three catalysts were selective for both aromatic and aliphatic Hydrocarbons in comparable proportions. With canola oil, between 12 and 48 wt % OLP was obtained. The optimum yields of Hydrocarbons were 65.8, 51.1, and 45.3 wt % of OLP for SAPO-5, SAPO-11, and MgAPO-36, respectively. SAPO-5 and SAPO-11 were highly selective for aromatic Hydrocarbons. On the other hand, MgAPO-36 produced high fractions of aliphatic Hydrocarbons at temperatures below 450 °C and high aromatic Hydrocarbons at temperatures above 450 °C. Furthermore, 8-17 and 5-63 wt % gas was produced with WDO and canola oil, respectively. The gas composition consisted mostly of C 1 -C 4 Hydrocarbons. The results showed that the conversion of bio-oils to Hydrocarbons with aluminophosphate catalyst was low as compared to HZSM-5 catalyst. However, some potential exists for the production of Hydrocarbons such as benzene (with WDO) and toluene and xylenes (with canola oil) as well as important gaseous Hydrocarbons such as ethylene, propylene, and n-butane.
Sonya M Billiard - One of the best experts on this subject based on the ideXlab platform.
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the role of the aryl hydrocarbon receptor pathway in mediating synergistic developmental toxicity of polycyclic aromatic Hydrocarbons to zebrafish
Toxicological Sciences, 2006Co-Authors: Sonya M Billiard, Alicia R Timmelaragy, Deena Wassenberg, Crystal J Cockman, Richard T Di GiulioAbstract:Planar halogenated aromatic Hydrocarbons (pHAHs), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), show strong binding affinity for the aryl hydrocarbon receptor (AHR) and are potent inducers of cytochrome P4501A (CYP1A). It is widely accepted that dioxin toxicity is largely AHR mediated; however, the role of CYP1A activity in causing that toxicity is less clear. Another class of AHR agonists of increasing concern because of their known toxicity and ubiquity in the environment is the polycyclic aromatic Hydrocarbons (PAHs). Like dioxin, some PAHs also cause toxicity to early life stages of vertebrates. Symptoms include increased cardiovascular dysfunction, pericardial and yolk sac edemas, subcutaneous hemorrhages, craniofacial deformities, reduced growth, and increased mortality rates. Although developmental effects are comparable between these two types of AHR agonists, the roles of both the AHR and CYP1A activity in PAH toxicity are unknown. As observed in previous studies with killifish (Fundulus heteroclitus), we demonstrate here that coexposure of zebrafish (Danio rerio) embryos to the PAH-type AHR agonist beta-naphthoflavone (BNF) and the CYP1A inhibitor alpha-naphthoflavone (ANF) significantly enhanced toxicity above that observed for single-compound exposures. In order to elucidate the role of the AHR pathway in mediating synergistic toxicity of PAH mixtures to early life stages, we used a morpholino approach to knock down expression of zebrafish AHR2 and CYP1A proteins during development. We observed that while knock down of AHR2 reduces cardiac toxicity of BNF combined with ANF to zebrafish embryos, CYP1A knockdown markedly enhanced toxicity of BNF alone and BNF + ANF coexposures. These data support earlier chemical inducer/inhibitor studies and also suggest that mechanisms underlying developmental toxicity of PAH-type AHR agonists are different from those of pHAHs. Identifying the pathways involved in PAH toxicity will provide for more robust, mechanistic-based tools for risk assessment of single compounds and complex environmental mixtures.
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the role of the aryl hydrocarbon receptor pathway in mediating synergistic developmental toxicity of polycyclic aromatic Hydrocarbons to zebrafish
Toxicological Sciences, 2006Co-Authors: Sonya M Billiard, Alicia R Timmelaragy, Deena Wassenberg, Crystal J Cockman, Richard T Di GiulioAbstract:Planar halogenated aromatic Hydrocarbons (pHAHs), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), show strong binding affinity for the aryl hydrocarbon receptor (AHR) and are potent inducers of cytochrome P4501A (CYP1A). It is widely accepted that dioxin toxicity is largely AHR mediated; however, the role of CYP1Aactivityincausingthattoxicityislessclear.Anotherclassof AHR agonistsofincreasing concernbecause oftheirknowntoxicity and ubiquity in the environment is the polycyclic aromatic Hydrocarbons(PAHs).Likedioxin,somePAHsalsocausetoxicitytoearly life stages of vertebrates. Symptoms include increased cardiovascular dysfunction, pericardial and yolk sac edemas, subcutaneous hemorrhages, craniofacial deformities, reduced growth, and increased mortality rates. Although developmental effects are comparable between these two types of AHR agonists, the roles of both the AHR and CYP1A activity in PAH toxicity are unknown. As observed in previous studies with killifish (Fundulus heteroclitus), we demonstrate here that coexposure of zebrafish (Danio rerio) embryos to the PAH-type AHR agonist b-naphthoflavone (BNF) and the CYP1A inhibitor a-naphthoflavone (ANF) significantly enhanced toxicity above that observed for single-compound exposures. In order to elucidate the role of the AHR pathway in mediating synergistic toxicity of PAH mixtures to early life stages, we used a morpholino approach to knock down expression of zebrafish AHR2 and CYP1A proteins during development. We observed that while knock down of AHR2 reduces cardiac toxicity of BNF combined with ANF to zebrafish embryos, CYP1A knockdown markedly enhanced toxicity of BNF alone and BNF + ANF coexposures. These data support earlier chemical inducer/inhibitor studies and also suggest that mechanisms underlying developmental toxicity of PAH-type AHR agonists are different from those of pHAHs. Identifying the pathways involved in PAH toxicity will provide for more robust, mechanistic-based tools for risk assessment
