Abstract  Vapor-liquid equilibrium at atmospheric pressure has been determined for the title ternary system. The data were correlated by various equations and the appropriate parameters are reported. © 1988, American Chemical Society. All rights reserved.

Abstract  Unleaded gasoline (UG), a complex mixture of over 300 hydrocarbons, induced liver tumors selectively in female mice and exhibited liver tumor promoting activity. UG also induced cell proliferation and cytochrome P-450-related enzyme activities in mouse liver, properties commonly associated with liver tumor promoters. To determine if the mitogenic and/or cytochrome P-450-inducing properties of UG reside in individual fractions of UG, UG was separated into four fractions on the basis of boiling point (BP): fraction 1, BP < 66 degrees C; fraction 2, 66 degrees C < BP < 100 degrees C; fraction 3, 100 degrees C < BP < 132 degrees C; fraction 4, BP > 132 degrees C. Fractions 1 and 2 were combined to form "light UG" (BP < 100 degrees C), and fractions 3 and 4 were combined to form "heavy UG" (BP > 100 degrees C). Female B6C3F1 mice were implanted with osmotic pumps containing 5-bromo-2'-deoxyuridine (BrdU) on d 1, treated by intragastric intubation with corn oil or 3000 mg/kg/d of light, heavy, or whole UG on d 2-4, and euthanized on d 5. Pentoxyresorufin O-dealkylase (PROD) and ethoxyresorufin O-deethylase (EROD) activities were assayed in hepatic microsomes, and hepatocyte BrdU labeling index (LI) was determined in liver sections. Whole UG and heavy UG caused comparable increases in hepatic PROD and EROD activities and the hepatocyte LI. Light UG caused relatively small increases in hepatic PROD and EROD activities and did not increase the hepatocyte LI. When fractions 3 and 4 were tested separately in the above treatment protocol, both fractions strongly induced hepatic PROD and weakly induced hepatic EROD activities. However, only fraction 3 increased the hepatocyte LI. To isolate mitogenic components in fraction 3, equimolar doses of individual chemicals in fraction 3 were tested in the above treatment protocol. Toluene did not increase the hepatocyte LI, whereas 2,2,3-trimethylpentane (TMP), 2,2,4-TMP, and 2,3,4-TMP all dramatically increased the hepatocyte LI. Thus, while the hepatic cytochrome P-450-inducing activity of UG was concentrated in components of UG with BPs > 100 degrees C, this activity apparently resides in UG components with a wide range of BPs. The mitogenic activity of UG, in contrast, was highly concentrated in components of UG with BPs ranging from approximately 100 to 132 degrees C, and quite possibly in specific TMPs.

Abstract  Two new hole-transporting materials, namely HFB-Cz and HFB-Dpa, were designed and synthesized by attaching carbazole and diphenylamine units to the hexakis(9,9-dihexyl-9H-fluoren-2-yl)benzene (HFB) core via Buchwald-Hartwig coupling reaction. The long alkyl chain and core rigidity endow these compounds with good solution processability and high thermal stability. HFB-Cz and HFB-Dpa exhibit significantly high glass transition temperatures (225 and 154 degrees C) relative to widely used hole-transporting materials, such as N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4, 4'-diamine (TPD, 65 degrees C) and 1,4-bis((1-naphthylphenyl)amino)biphenyl (NPB, 96 degrees C). Solution-processed green OLED devices using HFB-Cz and HFB-Dpa as hole-transporting materials exhibit very high efficiencies with a maximum current efficiency up to 6.2 cd A(-1). These efficiencies are substantially higher than the NPB-based control device, and are among the highest for the hole-transporting materials in similar device configuration.

Abstract  The in vitro metabolism of 1-propyl halides (chloride, bromide, and iodide) by hepatic microsomes from phenobarbital-induced rats was examined. The following metabolites were detected: propene, 1,2-epoxypropane, 1,2-propanediol, propionic acid, and undefined species bound to protein (for propyl chloride). The addition of exogenous glutathione to the incubation mixture led to the production of S-(1'-propyl)glutathione and S-(2'-hydroxy-1'-propyl)glutathione. The ratio of the metabolites resulting from C1-C2 functionalization [propene, 1,2-propanediol, and S-(2'-hydroxy-1'-propyl)glutathione] to that resulting from C1 functionalization (propionic acid) increased as the halide progressed down the halide order chloride bromide, and iodide. Mechanisms which rationalize the distribution of propyl halide metabolites as a function of the halide are discussed. The preferred mechanism interprets that the results obtained are a consequence of the partitioning of the initial metabolic transformation between alpha-hydroxylation and halogen oxygenation pathways.

Abstract  Many states are considering, and some states have actively pursued, banning the use of perchloroethylene (PERC) in dry cleaning establishments. Proposed legislation has led many dry cleaners to consider the use of products that contain greater than 90% n-propyl bromide (n-PB; also called 1-bromopropane or 1-BP). Very little information is known about toxicity and exposure to n-PB. Some n-PB-containing products are marketed as nonhazardous and "green" or "organic." This has resulted in some users perceiving the solvent as nontoxic and has resulted in at least one significant poisoning incident in New Jersey. In addition, many dry cleaning operators may not realize that the machine components and settings must be changed when converting from PERC to n-PB containing products. Not performing these modifications may result in overheating and significant leaks in the dry cleaning equipment. A preliminary investigation was conducted of the potential exposures to n-PB and isopropyl bromide (iso-PB; also called 2-bromopropane or 2-BP) among dry cleaners in New Jersey who have converted their machines from PERC to these new solvent products. Personal breathing zone and area samples were collected using the National Institute for Occupational Safety and Health Sampling and Analytical Method 1025, with a slight modification to gas chromatography conditions to facilitate better separation of n-PB from iso-PB. During the preliminary investigation, exposures to n-PB among some workers in two of three shops were measured that were greater than the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) for n-PB. The highest exposure measured among a dry cleaning machine operator was 54 parts per million (ppm) as an 8-hr time-weighted average, which is more than 5 times the ACGIH TLV of 10 ppm. The preliminary investigation also found that the work tasks most likely to result in the highest short-term exposures included the introduction of solvent to the machine, maintenance of the machine, unloading and handling of recently cleaned clothes, and interrupting the wash cycle of the machine. In addition, this assessment suggested that leaks may have contributed to exposure and may have resulted from normal machine wear over time, ineffective maintenance, and from the incompatibility of n-PB with gasket materials.

Abstract  This paper reports a new HTL material that has high glass-transition temperatures (T-g) and excellent thermal properties. The synthesized material was N,N'-diethyl-3,3'-bicarbazyl (DEBC), N,N'-diphenyl-3,3'-bicarbazyl (DPBC) and N,N'-dinaphthyl-3,3'-bicarbazyl (DNBC). The device that used DPBC as HTL showed the highest efficiency of 4.95 cd/A and 2.22 Im/W at 10 mA/cm(2). This is an improvement by more than 10% from the luminance efficiency of NPB, a commercialized material.

Abstract  Simple and rapid chemical indices of soil nitrogen (N)-supplying capacity are necessary for fertilizer recommendations. In this study, pot experiment involving rice, anaerobic incubation, and chemical analysis were conducted for paddy soils collected from nine locations in the Taihu Lake region of China. The paddy soils showed large variability in N-supplying capacity as indicated by the total N uptake (TNU) by rice plants in a pot experiment, which ranged from 639.7 to 1,046.2 mg N pot(-1) at maturity stage, representing 5.8% of the total soil N on average. Anaerobic incubation for 3, 14, 28, and 112 days all resulted in a significant (P < 0.01) correlation between cumulative mineral NH (4) (+) -N and TNU, but generally better correlations were obtained with increasing incubation time. Soil organic C, total soil N, microbial C, and ultraviolet absorbance of NaHCO(3) extract at 205 and 260 nm revealed no clear relationship with TNU or cumulative mineral NH (4) (+) -N. Soil C/N ratio, acid KMnO(4)-NH (4) (+) -N, alkaline KMnO(4)-NH (4) (+) -N, phosphate-borate buffer extractable NH (4) (+) -N (PB-NH (4) (+) -N), phosphate-borate buffer hydrolyzable NH (4) (+) -N (PB(HYDR)-NH (4) (+) -N) and hot KCl extractable NH (4) (+) -N (H(KCl)-NH (4) (+) -N) were all significantly (P < 0.05) related to TNU and cumulative mineral NH (4) (+) -N of long-term incubation (> 28 days). However, the best chemical index of soil N-supplying capacity was the soil C/N ratio, which showed the highest correlation with TNU at maturity stage (R = -0.929, P < 0.001) and cumulative mineral NH (4) (+) -N (R = -0.971, P < 0.001). Acid KMnO(4)-NH (4) (+) -N plus native soil NH (4) (+) -N produced similar, but slightly worse predictions of soil N-supplying capacity than the soil C/N ratio.

Abstract  1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br((-))] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br((-)) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers.

Abstract  We present trajectory-based estimates of Ozone Depletion Potentials (ODPs) for very short-lived halogenated source gases as a function of surface emission location. The ODPs are determined by the fraction of source gas and its degradation products which reach the stratosphere, depending primarily on tropospheric transport and chemistry, and the effect of the resulting reactive halogen in the stratosphere, which is determined by stratospheric transport and chemistry, in particular by stratospheric residence time. Reflecting the different timescales and physico-chemical processes in the troposphere and stratosphere, the estimates are based on calculation of separate ensembles of trajectories for the troposphere and stratosphere. A methodology is described by which information from the two ensembles can be combined to give the ODPs.

The ODP estimates for a species with a fixed 20 d life-time, representing a compound like n-propyl bromide, are presented as an example. The estimated ODPs show strong geographical and seasonal variation, particularly within the tropics. The values of the ODPs are sensitive to the inclusion of a convective parametrization in the trajectory calculations, but the relative spatial and seasonal variation is not. The results imply that ODPs are largest for emissions from south and south-east Asia during Northern Hemisphere summer and from the western Pacific during Northern Hemisphere winter. Large ODPs are also estimated for emissions throughout the tropics with non-negligible values also extending into northern mid-latitudes, particularly in the summer. These first estimates, whilst made under some simplifying assumptions, show larger ODPs for certain emission regions, particularly south Asia in NH summer, than have typically been reported by previous studies which used emissions distributed evenly over land surfaces.

Abstract  While scientific knowledge of the potential health significance of chemical exposures has grown, experimental methods for predicting the carcinogenicity of environmental agents have not been substantially updated in the last two decades. Current methodologies focus first on identifying genotoxicants under the premise that agents capable of directly damaging DNA are most likely to be carcinogenic to humans. Emphasis on the distinction between genotoxic and non-genotoxic carcinogens is also motivated by assumed implications for the dose-response curve; it is purported that genotoxicants would lack a threshold in the low dose region, in contrast to non-genotoxic agents. However, for the vast majority of carcinogens, little if any empirical data exist to clarify the nature of the cancer dose-response relationship at low doses in the exposed human population. Recent advances in scientific understanding of cancer biology-and increased appreciation of the multiple impacts of carcinogens on this disease process-support the view that environmental chemicals can act through multiple toxicity pathways, modes and/or mechanisms of action to induce cancer and other adverse health outcomes. Moreover, the relationship between dose and a particular outcome in an individual could take multiple forms depending on genetic background, target tissue, internal dose and other factors besides mechanisms or modes of action: inter-individual variability and susceptibility in response are, in turn, key determinants of the population dose-response curve. New bioanalytical approaches (e.g., transcriptomics, proteomics, and metabolomics) applied in human, animal and in vitro studies could better characterize a wider array of hazard traits and improve the ability to predict the potential carcinogenicity of chemicals. Published by Elsevier B.V

Abstract  Lots of chemicals are produced in chemical industry and used everywhere as convenient and indispensable materials in daily life and industry. Moreover, many new chemicals are needed to produce competitive new goods such as new medicines, new dyestuffs, new agricultural chemicals and others. Main chemicals used in industry have reached to more than 50,000 kinds. And many workers are exposed to chemicals and injured all over the world. To protect the workers in small workplaces against hazardous chemicals is one of the most important tasks of occupational health. n-Hexane, lead and 1-bromopropane poisoning are shown as examples for health hazards and preventive measures in small workplaces. Preventive measure such as TLV or OEL, Material Safety Data sheets, health check-up, comprehensive cooperation among employers, workers, researchers, industrial physicians and administrative officers, and information on toxicity are discussed.

Abstract  On January 21, 2015, The United States Environmental Protection Agency (US EPA) announced the receipt of a complete petition requested the chemical n-Propyl Bromide (nPB, CAS # 106-94-5) be added to the list of hazardous air pollutants (HAPs) listed in Section 112 (b)(1) of the Clean Air Act (CAA) (CFR Vol. 80, No. 25, 6676-6679; Docket ID No. EPA-HQ-OAR-2014-0471). US EPA indicated that petitioners modeled air emissions from five facilities that use nPB. US EPA has solicited comments on the technical merits of this information. Trinity performed a critical evaluation of the methodologies and assumptions used by the petitioners to estimate emissions from each of the five facilities modeled by Exponent. Trinity also obtained current usage and emission data and estimated current emissions for facilities that were modeled by Gradient.

Abstract  Occupational exposure to trichloroethylene (TRIC) and perchloroethylene (PERC) in metal degreasing is analyzed by calculating airborne concentrations for a large set of possible exposure scenarios (Scenario-Based Risk Assessment, SceBRA). Different types of degreasing machines ranging from open-top machines used until the 1980s to closed-loop nonvented machines used since the 1990s are investigated; the scope of the study is Germany. Concentrations are calculated for different kinds of releases (emissions from open baths, leakage, release of contaminated air during loading and unloading) with a dynamic two-box model for the near-field and the far-field. The concentration estimates are in good agreement with measured data. The airborne concentrations are compared to maximum workplace concentrations (MAK values). The full set of scenarios shows for which situations MAK values were exceeded and how the transition to newer degreasing machines reduced the occupational exposure by more than one order of magnitude. In addition, numbers of exposed workers are estimated for different years. While more than 25,000 workers in the near-field were exposed to TRIC and PERC in 1985, the number is below 3000 since 1996, which is mainly due to technology changes, rationalization, automatization, and replacement of TRIC and PERC by nonchlorinated solvents.

Abstract  Benzophenone (BP)-type UV filters are commonly used in our daily life. 2-hydroxy-4-methoxy benzophenone (BP-3), 4-hydroxy benzophenone (4-HBP), 2,4-dihydroxy benzophenone (BP-1), 2,2',4,4'-tetrahydroxy benzophenone (BP-2) and 2,2'-dihydroxy-4-methoxy benzophenone (BP-8) were measured in urine samples from Chinese young adults. The results indicated that Chinese young adults were widely exposed to BP-3, BP-1, and 4-HBP, with the median concentrations of 0.55, 0.21, and 0.08 ng/mL, respectively. No significant difference was found between males and females, between urban and rural population. The correlations between urinary concentrations provided important indications for sources and metabolic pathways of target compounds. The estimated daily excretion doses of BP-3, 4-HBP, BP-1, BP-2 and BP-8 were 27.2, 2.24, 5.86, 0.76 and 0.30 ng/kg-bw/day, respectively. The ratio of exposure to excretion must be considered for the exposure assessment with chemicals based on urine measurement. This is the first nationwide study on BP-derivatives with young adults in China. (C) 2015 Elsevier Ltd. All rights reserved.