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Trimethylbenzenes (Interagency Science Discussion Draft)

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Data/Software
Data/ Software

Results of the BMD analyses for 1,2,4-TMB, 1,2,3-TMB, and 1,3,5-TMB

Author: U.S. EPA (2016) HERO ID: 3103169

[Less] : This zipfile contains all input files (.dax files), analysis files (.opt, .ssn, .(d), and .002 files), . . . [More] : This zipfile contains all input files (.dax files), analysis files (.opt, .ssn, .(d), and .002 files), and output files (.out, .emf, and .plt files) used in and generated by the BMD analyses on endpoints considered for the derivation of reference values for 1,2,4-TMB, 123, and 1,3,5-TMB in the Interagency Science Discussion draft of the Toxicological Review for Trimethylbenzenes. This zipfile also contains all BMDS Wizard files (macro enabled Excel workbooks, .xlsm) that were used in the BMD modeling analyses. These BMDS Wizard files store within them all the modeling results for an individual endpoint, and can be used to interpret these endpoint-specific results holistically, rather than inspecting model-specific .out and .plt files. Lastly, this zipfile contains a modeling report (.docx) for each modeling analysis; these reports were used to create the BMD Modeling appendix (Appendix D) in the Supplemental Information Document for Trimethylbenzenes.

Data/Software
Data/ Software

PBPK data files for TMB (updated February 2016)

Author: U.S. EPA (2016) [Data files]. Research Triangle Park, NC: U.S. Environmental Protection Agency. [PBPK] HERO ID: 3103168

[Less] This model code package contains the PBPK files used in the testing and validation of the PBPK model . . . [More] This model code package contains the PBPK files used in the testing and validation of the PBPK model used in the Toxicological Review for Trimethylbenzenes, as well the files used in the PBPK extrapolations of inhalation data for the purpose of deriving reference concentrations, and the route-to-route extrapolation of inhalation data to oral exposures for the purpose of deriving reference doses.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Hemimellitene (1,2,3-trimethylbenzene) in the liver, lung, kidney, and blood, and dimethylbenzoic acid isomers in the liver, lung, kidney and urine of rats after single and repeated inhalation exposure to hemimellitene

Authors: Świercz, R; Majcherek, W; Wąsowicz, W (2016) International Journal of Occupational Medicine and Environmental Health 29:113-128. HERO ID: 3044616

[Less] OBJECTIVES: The aim of the study has been to explore hemimellitene distribution in blood, liver, lung . . . [More] OBJECTIVES: The aim of the study has been to explore hemimellitene distribution in blood, liver, lung and kidney as well as toxicokinetics of its elimination from blood of rats after single and repeated inhalation exposure to this compound. Tissue distribution and excretion with urine of 2-dimethylbenzoic acids (2,3-DMBA and 2,6-DMBA) were also evaluated.

MATERIAL AND METHODS: Male outbred IMP:WIST rats were used in the experiment. The animals were exposed to hemimellitene vapors at the nominal concentration of 25 ppm, 100 ppm, and 250 ppm in the dynamic inhalation chambers for 6 h for single exposure purpose and for 4 weeks (6 h/day for 5 day/week) for repeated exposure purposes.

RESULTS: Significantly lower concentrations of hemimellitene were detected in the blood and tissues of animals after repeated inhalation exposure of animals to hemimellitene vapors, which points to reduced retention of the chemical in the lungs of the experimental rats. The trend of hemimellitene elimination from the blood depended solely on exposure intensity, irrespective of exposure time, both after single and repeated exposure. As regards the 2 determined hemimellitene metabolites, the major trend of the metabolic transformation involved formation of 2,3-DMBA.

CONCLUSIONS: The significantly higher urinary 2,3-DMBA concentration after repeated exposure shows that hemimellitene induces enzymatic processes in the rat.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Toxicity of seven priority hazardous and noxious substances (HNSs) to marine organisms: Current status, knowledge gaps and recommendations for future research

Authors: Rocha, AC; Reis-Henriques, MA; Galhano, V; Ferreira, M; Guimarães, L (2016) Science of the Total Environment 542:728-749. [Review] HERO ID: 3068437

[Less] Shipping industry and seaborne trade have rapidly increased over the last fifty years, mainly due to . . . [More] Shipping industry and seaborne trade have rapidly increased over the last fifty years, mainly due to the continuous increasing demand for chemicals and fuels. Consequently, despite current regulations, the occurrence of accidental spills poses an important risk. Hazardous and noxious substances (HNSs) have been raising major concern among environmental managers and scientific community for their heterogeneity, hazardous potential towards aquatic organisms and associated social-economic impacts. A literature review on ecotoxicological hazards to aquatic organisms was conducted for seven HNSs: acrylonitrile, n-butyl acrylate, cyclohexylbenzene, hexane, isononanol, trichloroethylene and xylene. Information on the mechanisms of action of the selected HNS was also reviewed. The main purpose was to identify: i) knowledge gaps in need of being addressed in future research; and ii) a set of possible biomarkers suitable for ecotoxicological assessment and monitoring in both estuarine and marine systems. Main gaps found concern the scarcity of information available on ecotoxicological effects of HNS towards marine species and their poorly understood mode of action in wildlife. Differences were found between the sensitivity of freshwater and seawater organisms, so endpoints produced in the former may not be straightforwardly employed in evaluations for the marine environment. The relationship between sub-individual effects and higher level detrimental alterations (e.g. behavioural, morphological, reproductive effects and mortality) are not fully understood. In this context, a set of biomarkers associated to neurotoxicity, detoxification and anti-oxidant defences is suggested as potential indicators of toxic exposure/effects of HNS in marine organisms. Overall, to support the development of contingency plans and the establishment of environmental safety thresholds, it will be necessary to undertake targeted research on HNS ecotoxicity in the marine environment. Research should address these issues under more realistic exposure scenarios reflecting the prevailing spatial and temporal variability in ecological and environmental conditions.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Emission reduction potential in a light-duty diesel engine fueled by JP-8

Authors: Lee, J; Lee, J; Chu, S; Choi, H; Min, K (2015) HERO ID: 3017974

[Less] In this research, the effects of EGR (exhaust gas recirculation) and multiple injection strategy with . . . [More] In this research, the effects of EGR (exhaust gas recirculation) and multiple injection strategy with two pilots on the emissions and combustion characteristics of JP-8 fueled light-duty diesel engine were systemically investigated. Also, the potential of reducing NOx (nitrogen oxides) and PM (particulate matter) emissions with JP-8 in a light-duty diesel engine was evaluated. To understand the combustion phenomenon of JP-8, two different injection modes (single injection and multiple injection with two pilots) were applied. Under the single injection mode, the difference in the ignition delay between using JP-8 and diesel fuel became clear. Differently, under multiple injections with two pilots, the ignition delays of both cases were nearly the same due to the higher in the cylinder temperature cause by the combustion of the pilot injections. Finally, under multiple injection mode, more EGR (exhaust gas recirculation) could be applied to JP-8 combustion than in conventional diesel combustion while maintaining the same mass fraction burned 50% (MFB 50) to attain the same fuel conversion efficiency. As a result, NOx and PM emissions could be reduced by half when using JP-8 without decreasing the fuel conversion efficiency. (C) 2015 Elsevier Ltd. All rights reserved.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Effect of Cetane Improver on Combustion and Emission Characteristics of Coal-Derived Sasol Isomerized Paraffinic Kerosene in a Single Cylinder Diesel Engine

Authors: Zheng, Z; Joshi, U; Henein, N; Sattler, E (2015) HERO ID: 2953943

[Less] Sasol isomerized paraffinic kerosene (IPK) is a coal-derived synthetic fuel under consideration as a . . . [More] Sasol isomerized paraffinic kerosene (IPK) is a coal-derived synthetic fuel under consideration as a blending stock with JP-8 for use in military ground vehicles. Since Sasol IPK is a low ignition quality fuel with derived cetane number (DCN) of 31, there is a need to improve its ignition quality. This paper investigates the effect of adding different amounts of Lubrizol 8090 cetane improver to Sasol IPK on increasing its DCN. The experimental investigation was conducted in a single cylinder research type diesel engine. The engine is equipped with a common rail injection system and an open engine control unit. Experiments covered different injection pressures and intake air temperatures. Analysis of test results was made to determine the effect of cetane improver percentage in the coal-derived Sasol IPK blend on auto-ignition, combustion and emissions of carbon monoxide (CO), total unburned hydrocarbon (HC), oxides of nitrogen (NOx), and particulate matter (PM). In addition, the effect of cetane improver on the apparent activation energy of the global auto-ignition reactions was determined.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Aerobic oxidation of p-cresols to 4-hydroxy benzaldehydes catalyzed by cobaltous chloride/NHPI/salen-Cu(II) catalytic system

Authors: Ma, W; Zhang, Y; Li, X; Zhao, J (2015) HERO ID: 3044703

[Less] Oxidation of 2-methoxy-p-cresol, p-cresol, 2-bromo-p-cresol to their corresponding 4-hydroxybenzaldehydes . . . [More] Oxidation of 2-methoxy-p-cresol, p-cresol, 2-bromo-p-cresol to their corresponding 4-hydroxybenzaldehydes with atmospheric molecular oxygen as oxidant and a combination of cobaltous chloride and N-hydroxyphthalimide (NHPI) as catalyst in methanol has been investigated for the first time. The results indicated that the reaction progress was related to the substituents in the structures of the substrates: the electron-donating group methoxy favors the aerobic reaction but the electron-withdrawing group Br is detrimental to the reaction. The introduction of salen-Cu(II) complexes as the third component into the cobaltous chloride/NHPI catalytic system can considerably improve the aerobic oxidation of p-cresol and 2-brom-p-cresol to the corresponding 4-hydroxybenzaldes.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Ignition delay times of conventional and alternative fuels behind reflected shock waves

Authors: Zhu, Y; Li, S; Davidson, DF; Hanson, RK (2015) HERO ID: 2896779

[Less] The auto-ignition characteristics of two distillate jet fuels and fifteen alternative fuels (including . . . [More] The auto-ignition characteristics of two distillate jet fuels and fifteen alternative fuels (including fuel blends) were investigated using shock-tube/laser-absorption methods. Ignition delay times were measured behind reflected shock waves over a range of temperatures, 1047-1520 K, and equivalence ratios, 0.25-2.2, in two pressure and mixture regimes: for fuel/air mixtures at 2.07-8.27 atm, and for fuel/4% oxygen(O-2)/ argon(Ar) mixtures at 15.9-44.0 atm. In both pressure ranges, the ignition delay times of the alternative fuels and the blends with conventional fuels were found to be similar to those of conventional fuels but with some small systematic differences manifesting the different fuel types. In particular, for alternative aviation fuels, alcohol-to-jet fuels were found to be generally less reactive than Fischer-Tropsch paraffinic kerosenes or hydro-processed renewable jet fuels. Comparisons were also made of the ignition delay time data with detailed kinetic modeling for selected fuels. These comparisons show that existing multi-component surrogate/mechanism combinations can successfully predict the behavior of these fuels over the conditions studied. For those fuels lacking kinetic models, the current ignition delay time measurements provide useful target data for development and validation of relevant surrogate mixtures and reaction mechanisms. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Synthesis, characterization and applications of vinyl functionalized N-heterocyclic carbene supported ruthenium(II) derivatives

Authors: Suresh, P; Munisamy, V; Prabusankar, G (2015) HERO ID: 2899377

[Less] New ruthenium(II) N-heterocyclic carbene complexes of the general formula [ArCH2(VIm)RuCl2(p-cymene)] . . . [More] New ruthenium(II) N-heterocyclic carbene complexes of the general formula [ArCH2(VIm)RuCl2(p-cymene)] (VIm = vinylimidazole; Ar = mesitylene (5) or napthalene (6)) are obtained from the transmetallation reaction between [MesCH(2)(VIm)AgBr] (Mes = mesitylene (3)) or [NpCH2(VIm)AgCl] (Np = napthalene (4)) and [(p-cymene)RuCl2](2). The silver carbene complexes (3) and (4) are synthesized from the direct reaction between the corresponding pi-functionalized imidazolium salts, [MesCH(2)(VIm)Br] (1) or [NpCH2(VIm)Cl] (2), with silver oxide in good yield. The compounds (1), (2), (5) and (6) are characterized by elemental analysis, FT-lR and multinuclear (H-1 and C-13) NMR spectroscopy. Furthermore, ligand (1) is characterized by single crystal X-ray diffraction technique. The coordination mode and possible olefin-Ru pi-interaction in (5) and (6) are investigated. The complexes (5) and (6) are stable and soluble in dichloromethane and chloroform.Compounds (5) and (6) are catalytically active towards the hydrogen transfer reactions.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Synthesis and mechanical characterization of mechanically strong, polyurea-crosslinked, ordered mesoporous silica aerogels

Authors: Churu, G; Zupancic, B; Mohite, D; Wisner, C; Luo, H; Emri, I; Sotiriou-Leventis, C; Leventis, N; Lu, H (2015) HERO ID: 2897771

[Less] Mechanically strong polymer-crosslinked templated silica aerogel (CTSA) monoliths with ordered tubular . . . [More] Mechanically strong polymer-crosslinked templated silica aerogel (CTSA) monoliths with ordered tubular mesopores were synthesized through an acid-catalyzed, surfactant-templated sol-gel process followed by covalent crosslinking of the elementary building blocks with polyurea. Specifically, a structure-directing reagent (triblock copolymer, Pluronic P123) was used in combination with variable amounts of a micelle-swelling reagent (1,3,5-trimethylbenzene) to regulate the size, shape, morphology of the elementary building blocks, as well as the pore size distribution of acid-catalyzed silica. The structure was subsequently treated with variable concentrations of a diisocyanate that reacts with surface -OH groups as well as residual gelation water adsorbed on the surface of silica. The developing polymer (polyurea) adheres to the walls of the mesoporous tubes and leaves macropores open. Rather than using a typical supercritical fluid (typically from CO2) drying protocol, the polymer-crosslinked materials of this study are strong enough to withstand stresses imposed by evaporating solvents and were dried from pentane under ambient pressure. The morphostructural properties of CTSAs were characterized before and after compression testing using a battery of methods including SEM, TEM and small-angle X-ray scattering. Mechanical properties were investigated using quasi-static compression tests, tensile, high-strain-rate dynamic tests as well as shear creep measurements. In addition, dynamic mechanical analysis as well as heat transfer tests was conducted. The Young's modulus was found to be about 800 MPa while the specific energy absorption was as high as 123 J/g, making this material a prime candidate for ballistic protection.

Mechanically strong polymer-crosslinked templated silica aerogel (CTSA) monoliths with ordered tubular mesopores were synthesized through an acid-catalyzed, surfactant-templated sol-gel process followed by covalent crosslinking of the elementary building blocks with polyurea, leaving macropores open. Using pentane under ambient pressure drying protocol, the CTSAs are strong enough to withstand stresses imposed by evaporating solvents. The mechanical and morphostructural properties of CTSAs were characterized using SEM, TEM and small-angle X-ray scattering (SAXS). The Young's modulus was found to be about 800 MPa while the specific energy absorption was as high as 123 J/g, making this material a prime candidate for energy absorption under impact.TEM/SEM images and SAXS of X-MP4-T045-11/94 templated aerogel. (a) TEM images before compression; (b) TEM images after 85 % compressive strain; (c) SAXS data at different strain. (d) SEM images before compression; (e) SEM images after 23 % strain; (f) SEM images after 83 % strain. Insets of (e) and (f) are the compressive stress-strain curves.