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Trimethylbenzenes (Interagency Science Discussion Draft)

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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

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 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.

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

Mesoporous calcium-silicon xerogels with mesopore size and pore volume influence hMSC behaviors by load and sustained release of rhBMP-2

Authors: Song, W; Li, X; Qian, Jun; Lv, G; Yan, Y; Su, J; Wei, Jie (2015) International Journal of Nanomedicine 10:1715-1726. HERO ID: 2898472

[Less] Mesoporous calcium-silicon xerogels with a pore size of 15 nm (MCS-15) and pore volume of 1.43 cm(3)/g . . . [More] Mesoporous calcium-silicon xerogels with a pore size of 15 nm (MCS-15) and pore volume of 1.43 cm(3)/g were synthesized by using 1,3,5-mesitylene (TMB) as the pore-expanding agent. The MCS-15 exhibited good degradability with the weight loss of 50 wt% after soaking in Tris-HCl solution for 56 days, which was higher than the 30 wt% loss shown by mesoporous calcium-silicon xerogels with a pore size of 4 nm (MCS-4). The pore size and pore volume of MCS-15 had significant influences on load and release of recombinant human bone morphogenetic protein-2 (rhBMP-2). The MCS-15 had a higher capacity to encapsulate a large amount of rhBMP-2; it could adsorb 45 mg/g of rhBMP-2 in phosphate-buffered saline after 24 hours, which was more than twice that with MCS-4 (20 mg/g). Moreover, the MCS-15 system exhibited sustained release of rhBMP-2 as compared with MCS-4 system (showing a burst release). The MCS-15/rhBMP-2 system could promote the proliferation and differentiation of human mesenchymal stem cells, showing good cytocompatibility and bioactivity. The results indicated that MCS-15, with larger mesopore size and higher pore volume, might be a promising carrier for loading and sustained release of rhBMP-2, which could be used as bone repair material with built-in osteoinduction function in bone reconstruction.

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

Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities

Authors: Van Wyngarden, AL; Perez-Montano, S; Bui, JVH; Li, ESW; Nelson, TE; Ha, KT; Leong, L; Iraci, LT (2015) Atmospheric Chemistry and Physics 15:4225-4239. HERO ID: 2902441

[Less] Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric . . . [More] Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt %) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H2SO4) with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions) that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and H-1 nuclear magnetic resonance (NMR) spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal) and 1,3,5-trimethylbenzene that was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher-order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence of products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal and methylglyoxal have the potential to produce significant organic aerosol mass and therefore could potentially impact chemical, optical and/or cloud-forming properties of aerosols, especially if the products partition to the aerosol surface.

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

Catalytic Upgrading of 5-Hydroxymethylfurfural to Drop-in Biofuels by Solid Base and Bifunctional Metal-Acid Catalysts

Authors: Bohre, A; Saha, B; Abu-Omar, MM (2015) ChemSusChem 8:4022-4029. HERO ID: 3044606

[Less] Design and synthesis of effective heterogeneous catalysts for the conversion of biomass intermediates . . . [More] Design and synthesis of effective heterogeneous catalysts for the conversion of biomass intermediates into long chain hydrocarbon precursors and their subsequent deoxygenation to hydrocarbons is a viable strategy for upgrading lignocellulose into distillate range drop-in biofuels. Herein, we report a two-step process for upgrading 5-hydroxymethylfurfural (HMF) to C9 and C11 fuels with high yield and selectivity. The first step involves aldol condensation of HMF and acetone with a water tolerant solid base catalyst, zirconium carbonate (Zr(CO3 )x ), which gave 92 % C9 -aldol product with high selectivity at nearly 100 % HMF conversion. The as-synthesised Zr(CO3 )x was analysed by several analytical methods for elucidating its structural properties. Recyclability studies of Zr(CO3 )x revealed a negligible loss of its activity after five consecutive cycles over 120 h of operation. Isolated aldol product from the first step was hydrodeoxygenated with a bifunctional Pd/Zeolite-β catalyst in ethanol, which showed quantitative conversion of the aldol product to n-nonane and 1-ethoxynonane with 40 and 56 % selectivity, respectively. 1-Ethoxynonane, a low oxygenate diesel range fuel, which we report for the first time in this paper, is believed to form through etherification of the hydroxymethyl group of the aldol product with ethanol followed by opening of the furan ring and hydrodeoxygenation of the ether intermediate.

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

Comprehensive Analysis of Structure Activity Relationships of α-Ketoheterocycles as sn-1-Diacylglycerol Lipase α Inhibitors

Authors: Janssen, FJ; Baggelaar, MP; Hummel, JJ; Overkleeft, HS; Cravatt, BF; Boger, DL; van der Stelt, M (2015) HERO ID: 3044598

[Less] Diacylglycerol lipase α (DAGLα) is responsible for the formation of the endocannabinoid 2-arachidonoylglycerol . . . [More] Diacylglycerol lipase α (DAGLα) is responsible for the formation of the endocannabinoid 2-arachidonoylglycerol (2-AG) in the central nervous system. DAGLα inhibitors are required to study the physiological role of 2-AG. Previously, we identified the α-ketoheterocycles as potent and highly selective DAGLα inhibitors. Here, we present the first comprehensive structure-activity relationship study of α-ketoheterocycles as DAGLα inhibitors. Our findings indicate that the active site of DAGLα is remarkably sensitive to the type of heterocyclic scaffold with oxazolo-4N-pyridines as the most active framework. We uncovered a fundamental substituent effect in which electron-withdrawing meta-oxazole substituents increased inhibitor potency. (C6-C9)-acyl chains with a distal phenyl group proved to be the most potent inhibitors. The integrated SAR data was consistent with the proposed binding pose in a DAGLα homology model. Altogether our results may guide the design of future DAGLα inhibitors as leads for molecular therapies to treat neuroinflammation, obesity and related metabolic disorders.