Abstract  1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting solvents and suspect carcinogens and is in aerosol products, adhesives and solvents used for metal, precision and electronics cleaning. Toxicity of 1-BP is poorly understood, but it may be a neurologic, reproductive and hematologic toxin. Sparse exposure information prompted this exposure assessment study using air sampling, and measurement of urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving removal of bromide (Br) from the propyl group. One research objective was to evaluate the utility of urinary Br analysis for assessing 1-BP exposure using a relatively inexpensive, commercially available method. Complete 48 h urine specimens were obtained from 30 workers on two consecutive days at two facilities using 1-BP adhesives to construct polyurethane foam seat cushions and from seven unexposed control subjects. All of the workers' urine was collected into composite samples representing three daily time intervals (at work; after work but before bedtime; and upon wake-up) and analyzed for Br ion by inductively coupled plasma-mass spectrometry. Full-shift breathing zone samples were collected for 1-BP on Anasorb carbon molecular sieve sorbent tubes and analyzed by gas chromatography-flame ionization detection via NIOSH method 1025. Geometric mean (GM) breathing zone concentrations of 1-BP were 92 parts per million (p.p.m.) for adhesive sprayers and 11 p.p.m. for other jobs. For sprayers, urinary Br concentrations ranged from 77 to 542 milligrams per gram of creatinine [mg (g-cr)^-1] at work; from 58 to 308 mg (g-cr)^-1 after work; and from 46 to 672 mg (g-cr)^-1 in wake-up samples. Pre-week urinary Br concentrations for sprayers were substantially higher than for the non-sprayers and controls, with GMs of 102, 31 and 3.8 mg (g-cr)^-1, respectively. An association of 48 h urinary Br concentration with 1-BP exposure was statistically significant (r² = 0.89) for all jobs combined. This study demonstrates that urinary elimination is an important excretion pathway for 1-BP metabolism, and Br may be a useful biomarker of exposure.

Abstract  A new bipolar molecule containing hole-transporting and electron-transporting moieties has been synthesized and characterized. Using the bipolar molecule as a hole-transproter, a typical bilayer device yields a maximum current efficiency of 5.6 cd/A, which is much better than that of an NPB-based device.

Abstract  Ethylene oxide (EO) and propylene oxide (PO) are direct acting mutagens with high Swain-Scott s-values, which indicate that they react preferentially with ring nitrogens in the DNA. We have previously described that in the X-linked recessive lethal (RL) assay in Drosophila postmeiotic male germ cells EO is, per unit exposure dose, 5-10 times more mutagenic than PO. Furthermore, at the higher dose range of EO tested, 62.5-1000 ppm, up to 20-fold enhanced mutation rates were measured in the absence of maternal nucleotide excision repair (NER) compared to repair proficient conditions. The lower dose range of EO tested, 2-7.8 ppm, still produced a small increased mutation rate but without a significant elevated effect when the NER system is being suppressed. The lowest dose of PO tested, 15.6 ppm, produced only in NER- condition an increased mutation rate. The aim of the present study was to compare the mutagenic effect of EO and PO in the RL assay under XPG proficient and deficient conditions with the formation of N-7-(2-hydroxyethyl)guanine (7-HEG) and N-7-(2-hydroxypropyl)guanine (7-HPG), respectively, the major DNA adducts formed. The formation of 7-HEG and 7-HPG was investigated in Drosophila males exposed to EO and PO as a measure of internal dose for exposures ranging from 2 to 1000 or 2000 ppm, respectively, for 24h. Analysis of 7-HEG and 7-HPG, using a highly sensitive 32P-postlabelling assay, showed a linear increase of adduct levels over the entire dose range. The non-linear dose-response relationship for mutations could therefore not be explained by a reduced inhalation or increased detoxification at higher exposure levels. In analogy with the four times higher reactivity of EO the level of N-7-guanine alkylation per ppm was for EO 3.5-fold higher than that for PO. Per unit N-7-guanine alkylation EO was found to be slightly more mutagenic than PO, whereas PO was the more potent clastogenic agent. While this research has not identified the DNA lesions that cause the increase in repair deficient flies, it supports the hypothesis that efficient error-free repair of some N-alkylation products can explain why these agents tend to be weakly genotoxic or even inactive in repair-competent (premeiotic) germ cells of the mouse and the Drosophila fly.

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  In order to evaluate the response of antioxidant defense system of three sugar beet genotypes to drought stress and enhancing management of soil water content, a two-years field experiment was conducted at the Research Site of Sugar Beet Seed Institute in Karaj, Iran during 2008 and 2009. Irrigation treatments arranged in main plots during growing seasons included: 80 mm (I(1): as control), 130 mm (I(2)) and 180 mm (I(3)) evaporation from A class pan under surface irrigation method, 30 mm (I(4)), 80 mm (I(5)), 130 mm (I(6)) and 180 mm (I(7): as severe drought) evaporation with 100% volume of water requirement under trickle irrigation (Tape) method and 30 mm (I(8)) evaporation with 75% volume of water requirement under trickle irrigation (Tape) method. Genotypes included: 7112 (G(1)), BP-Karaj (G(2)) and BP-Mashhad (G(3)) were in sub plots. Results of the study showed that drought stress decreased root yield (RY) increased the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) in sugar beet leaves. There were significant differences among genotypes for antioxidant enzyme activity. Also, irrigation x genotype interactions showed significant difference on CAT and GPX activities. There was a negative correlation between enzymes activities and RY. Results of the study also indicated that water deficit stress causes production of reactive oxygen species (ROSs), which results in greater membrane permeability i.e., malondialdehyde (MDA) content and oxidative stress in the plants. Moreover, genotypes having greater levels of antioxidants showed better resistance to drought stress. (C) 2011 Friends Science Publishers

Abstract  The humoral immune response against sheep red blood cells (SRBC) is one of the most sensitive and frequently used end-points in evaluating the immunotoxicity of drugs and chemicals in experimental animals. Currently, most immunotoxicology studies measure the SRBC IgM antibody response by quantitating the number of SRBC-specific IgM antibody-forming cells using the hemolytic plaque assay. On the other hand, measurement of serum SRBC-specific IgM could be an easier, more cost effective endpoint in evaluating the SRBC antibody response in rodents. A validated method to measure SRBC-specific IgM, however, has not been developed. Thus, the objectives of the studies presented were to develop and validate an enzyme-linked immunosorbent assay (ELISA) for SRBC-specific IgM. Hemoglobin-free, detergent-solubilized membrane preparations were chosen as antigen for the ELISA. Various sources of SRBC were found to be equally useful, and as little as 0.1 micrograms of protein per well was optimal. Kinetic studies of the IgM response showed the peak day to be on Day 5 (mice) and Day 6 (rats). To validate the usefulness of the method for immunotoxicologic studies, serum SRBC-specific IgM levels and number of SRBC-specific plaque-forming cells were compared in rats and mice treated with two well-characterized immunosuppressive agents: benzo[a]pyrene and cyclophosphamide. Administration of these chemicals was found to produce very similar dose-dependent decreases in serum SRBC IgM and IgM-specific plaque-forming cells. These two endpoints were equally sensitive to the effects of the immunosuppressive drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

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  A series of carbazole derivatives was synthesized and their electrical and photophysical properties were investigated. It is shown that the triplet energy levels of these hosts are higher than that of the most popular blue phosphorescent material iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C(2')] picolinate (FIrpic) and the most extensively used phosphorescent host material 4,4'-N,N'-dicarbazole-biphenyl (CBP). These new host materials also showed good thermal stability and high glass transition temperatures (T(g)) ranging from 78 to 115 degrees C as the linkage group between the carbazoles was altered. Photophysical measurements indicate that the energy transfer between these new hosts and FIrpic is more efficient than that between CBP and FIrpic. Devices incorporating these novel carbazole derivatives as the host material doped with FIrpic were fabricated with the configurations of ITO/NPB (40 nm)/host:FIrpic (30 nm)/BCP (15 nm)/AlQ (30 nm)/LiF (1 nm)/Al (150 nm). High efficiencies (up to 13.4 cd/A) have been obtained when 1,4-bis (4-(9H-carbazol-9-yl)phenyl)cyclohexane (CBPCH) and bis(4-(9H-carbazol-9-yl)phenyl) ether (CBPE) were used as the host, respectively. Efficiencies obtained from these devices are significantly higher than the efficiency obtained with CBP as the host. At a bias voltage of similar to 20 V the maximum luminances of 20 342 and 17 766 cd/m(2) were achieved for CBPCH- and CBPE-based devices, respectively, which demonstrates that CBPCH and CBPE can be excellent host materials for blue electrophosphorescent OLEDs.

Abstract  By conjugating carbazole moiety to the different positions of the rigid skeleton 1,2-dipheny1-1H-phenanthro[9,10-d]imidazole, a series of hybrid bipolar phosphorescent hosts was synthesized, and their photophysical properties were investigated. The introduction of a rigid phenanthroimidazole moiety greatly improves their morphological stability, with high decomposition temperatures (T-d) and high glass transition temperatures (T-g) in the range of 394-417 and 113-243 degrees C, respectively. The highly efficient green and orange phosphorescent organic light-emitting diodes (PhOLEDs) have been achieved by employing these compounds as the phosphorescent hosts. For the device of ITO/MoO3 (10 nm)/NPB (80 nm)/TCTA (5 nm)/mPhBINCP:9 wt % Ir(ppy)(3) (20 nm)/TmPyPB (45 nm)/LiF (1 nm)/Al (100 nm), a maximum luminous efficiency (eta(c,max)) of 77.6 cd/A, maximum power efficiency (eta(p,max)) of 80.3 lm/W, and maximum external quantum efficiency (eta(EQA,max)) of 21% were obtained. Furthermore, these hosts are also applicable for the orange phosphorescent emitter (fbi)(2)Ir(acac), a yellow PhOLEDs with pPhBICP as host, for which a performance of eta(c,max) of 57.2 cd/A, eta(EQE,max) of 19.3%, and eta(p,max) of 59.8 lm/W was achieved. These results demonstrated that the phenanthroimidazole unit is an excellent electron-transporting group for constructing the bipolar phosphorescent host.

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  Neglecting health effects from indoor pollutant emissions and exposure, as currently done in Life Cycle Assessment (LCA), may result in product or process optimizations at the expense of workers' or consumers' health. To close this gap, methods for considering indoor exposure to chemicals are needed to complement the methods for outdoor human exposure assessment already in use. This paper summarizes the work of an international expert group on the integration of human indoor and outdoor exposure in LCA, within the UNEP/ SETAC Life Cycle Initiative. A new methodological framework is proposed for a general procedure to include human-health effects from indoor exposure in LCA. Exposure models from occupational hygiene and household indoor air quality studies and practices are critically reviewed and recommendations are provided on the appropriateness of various model alternatives in the context of LCA. A single-compartment box model is recommended for use as a default in LCA, enabling one to screen occupational and household exposures consistent with the existing models to assess outdoor emission in a multimedia environment. An initial set of model parameter values was collected. The comparison between indoor and outdoor human exposure per unit of emission shows that for many pollutants, intake per unit of indoor emission may be several orders of magnitude higher than for outdoor emissions. It is concluded that indoor exposure should be routinely addressed within LCA.

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.