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  To ascertain the neurotoxicity of 2-bromopropane and 1-bromopropane, three doses of 2-bromopropane (1.1, 3.7 and 11.0 mmol/kg), two doses of 1-bromopropane (3.7 and 11.0 mmol/kg), and a dose of 2,5-hexanedione (2,5-HD) as a positive reference (2.6 mmol/kg) dissolved in olive oil were subcutaneously injected into rats once a day, 5 d/wk for 4 weeks. A control group were injected with olive oil alone. The maximum motor conduction velocity (MCV) and the motor latency (ML) in rat tail nerve, as indexes of the electrophysiological changes, were investigated for 4 weeks. From 2 weeks after the injections, the MCV in the 1-bromopropane and 2-bromopropane-treated groups began to decrease in a dose-dependent fashion. These dose-related decreases continued, and the MCV in the groups injected with 1-bromopropane (11.0 mmol/kg) and 2-bromopropane (3.7 and 11.0 mmol/kg) decreased significantly compared with that in the control group. The ML in the 1-bromopropane and 2-bromopropane-treated groups increased in reverse correlation with the MCV decreases. The changes in ML occurred earlier than the MCV changes in the 1-bromopropane and 2-bromopropane-treated groups. The potency of the peripheral neurotoxic changes induced by 1-bromopropane and 2-bromopropane at the doses used in the present study was weaker than that observed in the positive reference 2,5-HD (2.6 mmol/kg) group.

Abstract  A number of the compounds proposed as replacements for substances controlled under the Montreal Protocol have extremely short atmospheric lifetimes, on the order of days to a few months. An important example is n-propyl bromide (also referred to as 1-bromopropane, CH2BrCH2CH3 or simplified as 1-C3H7Br or nPB). This compound, useful as a solvent, has an atmospheric lifetime of less than 20 days due to its reaction with hydroxyl. Because nPB contains bromine, any amount reaching the stratosphere has the potential to affect concentrations of stratospheric ozone. The definition of Ozone Depletion Potentials (ODP) needs to be modified for such short-lived compounds to account for the location and timing of emissions. It is not adequate to treat these chemicals as if they were uniformly emitted at all latitudes and longitudes as normally done for longer-lived gases. Thus, for short-lived compounds, policymakers will need a table of ODP values instead of the single value generally provided in past studies. This study uses the MOZART2 three-dimensional chemical-transport model in combination with studies with our less computationally expensive two-dimensional model to examine potential effects of nPB on stratospheric ozone. Multiple facets of this study examine key questions regarding the amount of bromine reaching the stratosphere following emission of nPB. Our most significant findings from this study for the purposes of short-lived replacement compound ozone effects are summarized as follows. The degradation of nPB produces a significant quantity of bromoacetone which increases the amount of bromine transported to the stratosphere due to nPB. However, much of that effect is not due to bromoacetone itself, but instead to inorganic bromine which is produced from tropospheric oxidation of nPB, bromoacetone, and other degradation products and is transported above the dry and wet deposition processes of the model. The MOZART2 nPB results indicate a minimal correction of the two-dimensional results in order to derive our final results: an nPB chemical lifetime of 19 days and an Ozone Depletion Potential range of 0.033 to 0.040 for assumed global emissions over landmasses, 19 days and 0.021 to 0.028, respectively, for assumed emissions in the industrialized regions of the Northern Hemisphere, and 9 days and 0.087 to 0.105, respectively, for assumed emission in tropical Southeast Asia.

Abstract  Vapor-liquid equilibrium at 101.3 kPa has been determined for the ternary system acetonitrile + methyl acetate + propyl bromide. The data were correlated by the Redlich-Kister and Wisniak-Tamir equations, and the appropriate parameters are reported. The activity coefficients of the ternary system can be predicted from those of the pertinent binary systems. No ternary azeotrope is present.

Abstract  In this paper, we focus on improvement of the monovalent cation perm-selectivity of a perfluorinated cation-exchange membrane, Nafion 117, by depositing an anion-exchange layer using a plasma surface modification process. The anion-exchange layer was deposited from 4-vinylpyridine monomer vapor followed by quaternization with 1-bromopropane. The transference number of divalent cation (Fe2+) through the membrane, t(Fe), decreased with increasing thickness of the plasma polymer layer at the expense of enhanced membrane resistance. A large interfacial resistance was observed between Nafion and the plasma polymer layer which was ascribed to the implantation of cationic species containing nitrogen. To avoid the formation of an interfacial layer, a novel method of plasma-induced surface modification was devised. After a Nafion 117 sheet was placed on an RF (radio-frequency) electrode and sputtered with an oxygen or argon plasma in order to produce active sites on the Nafion, 4-vinylpyridine or 3-(2-aminoethyl)aminopropyltrimethoxysilane vapor was introduced into the reactor to react with radical sites. t(Fe) decreased with increasing RF power. t(Fe) through Nafion modified with 3-(2-aminoethyl)aminopropyltrimethoxysilane was lower than that for Nafion modified with 4-vinylpyridine, probably due to its weak Si-C bond. Nafion treated by the plasma surface modification method exhibited a very high monovalent cation perm-selectivity compared with Nafion treated by the plasma polymerization method.

Abstract  Centrifuge extraction and Rotavapor recovery were used to determine the effect of solvent type (trichloroethylene and four n-propyl bromide products) on recovered asphalt binder properties. Mix variables included three binders mixed with each of two aggregate sources (one gradation). When recovered binder properties were compared to the original binder properties, the trichloroethylene solvent combined with the extraction and recovery processes occasionally produced higher (i.e., stiffer) recovered binders. One n-propyl bromide product appeared to be incompatible with the polymer-modified PG 76-22. This incompatibility was seen as a distinct stringy, rubber-like residue in the extractor. Fourier transform infrared analysis showed that this same product also seemed to inhibit or actually limit normal heat-related changes. Overall, the data indicate that n-propyl bromide solvents can be used as direct replacements for the chlorinated solvents historically used for hot-mix asphalt extraction and binder recovery.

Abstract  This paper presents methods for the surface modification of cotton woven fabric and polypropylene non-woven in order to make them antibacterial. In the case of cotton fabric, its surface was functionalised with chloroacetate groups by means of chloroacetyl chloride, using pyridine as a catalyst, followed by the quaternalisation of the chloroacetate groups with poly(4-vinylpyridine). In the second process polypropylene nonwoven was impregnated with a multimonomer containing vinyl groups, which were then changed into tertiary amine groups by the addition of diethylamine. These groups were quaternalised with propyl bromide. In the next method colloidal silver was incorporated into the nanolayers formed from polyelectrolytes on the polypropylene non-woven. Quantitative tests of bacteriological activity of the modified woven fabric and non-woven showed both bacteriostatic and bactericidal activities in relation to Escherichia coli. In addition, colloidal platinum was incorporated into previously deposited polyelectrolyte nanolayers in order to impart catalytic properties to fibers. The results obtained clearly show the catalytic action of such systems, the oxygen release from the hydrogen peroxide solution being an example.

Abstract  The heat capacity and parameters of fusion of 1-bromobutane (BuBr) were measured in the temperature range (5 to 370) K using adiabatic calorimetry. The thermodynamic functions for the compound in the crystal and liquid states were calculated from these data. On the basis of the experimental spectroscopic data and the results of quantum-chemical calculations, the ideal-gas properties for BuBr were calculated by methods of statistical thermodynamics. The obtained entropy S(m)degrees(g; 298.15 K) = 366.9 J.K(-1).mol(-1) is in excellent agreement with the value 367.0 +/- 1.2 J.K(-1).mol(-1) obtained from the experimental data. The ideal-gas thermodynamic properties were also calculated for isomeric bromobutanes and 1-butyl-3-methylimdiazolium bromide ionic liquids that allowed us to find the changes of thermodynamic properties in the reactions of synthesis of 1-butyl-3-methylimidazolium bromide isomers. The literature data on the enthalpies of formation for isomeric bromobutanes were collected, and the recommended values were developed. It was demonstrated that the synthesis of ionic liquids from bromoalkanes and 1-methylimidazole in the gas phase, unlike the liquid-phase reaction, is not a thermodynamically favorable process. It possesses more positive enthalpy changes and more negative entropy changes compared to the synthesis in the liquid phase.

Abstract  The rate constant for the gas phase reaction of OH radicals with BTP (2-bromo-3,3,3-trifluoropropene, CH2 = CBrCF3) was measured using a flash photolysis resonance-fluorescence technique over the temperature range 220 K to 370 K. The Arrhenius plot was found to exhibit noticeable curvature. The temperature dependence of the rate constant can be represented as k(BTP)(220 - 370 K) = 4.85 x 10(-13) x (T/298)(0.92) x exp{+613/T} cm(3) molecule(-1) s(-1). For atmospheric modeling purposes, k(BTP)(T) can be equally well represented by the standard Arrhenius expression k(BTP)(220 - 298 K) = 1.05 x 10(-12) x exp{+381/T} cm(3) molecule(-1) s(-1). The IR absorption cross-sections of BTP were also measured between 450 cm(-1) and 1900 cm(-1). BTP atmospheric lifetime, Ozone Depletion Potential (ODP), and Global Warming Potential (GWP) were evaluated in the Whole Atmosphere Community Climate Model for land emissions from 30 to 60 degrees N and from 60 degrees S to 60 degrees N. The global, annual average atmospheric lifetime of BTP in the former scenario was 7.0 days, its ODP was 0.0028, and its GWP (100-yr time horizon) was 0.0050; in the latter scenario, the global, annual average BTP lifetime was 4.3 days, ODP was 0.0052, and 100-yr GWP was 0.0028. The short lifetime, low ODP, and low GWP indicate that BTP should have minimal effects on ozone and climate. Little BTP reaches the stratosphere in either emission scenario, but 27% of the ozone loss in the 30 to 60 degrees N scenario and 46% of the ozone loss in the 60 degrees S to 60 N scenario occurs above the tropopause due to Br-y from BTP.

Abstract  The purposes of the present study are (1) to develop a sensitive analytical method to measure 1-bromopropane (1-BP) in urine, (2) to examine if 1-BP or bromide ion (Br) in urine is a useful biomarker of exposure to 1-BP, and (3) to identify the lowest 1-BP exposure concentration the method thus established can biomonitor. A factory survey was carried out on Friday, and 33 workers (all men) in cleaning and painting workshops participated; each worker was equipped with a diffusive sampler (carbon cloth KF-1500 as an adsorbent) to monitor 1-BP vapour for an 8-h shift, and offered a urine sample at the end of the shift for measurement of 1-BP and Br in urine. In addition, 10 non-exposed men offered urine samples as controls. The performance of the carbon cloth diffusive sampler was examined to confirm that the sampler is suitable for monitoring time-weighted average 1-BP vapour exposure. A head-space GC technique was employed for analysis of 1-BP in urine, whereas Br in urine was analysed by ECD-GC after derivatization to methyl bromide. The workers were exposed to vapours of seven other solvents (i.e. toluene, xylenes, ethylbenzene, acetone, etc.) in addition to 1-BP vapour; the 1-BP vapour concentration was 1.4 ppm as GM and 28 ppm as the maximum. Multiple regression analysis however showed that 1-BP was the only variable that influenced urinary 1-BP significantly. There was a close correlation between 1-BP in urine and 1-BP in air; the correlation coefficient (r) was >0.9 with a narrow variation range, and the regression line passed very close to the origin so that 2 ppm 1-BP exposure can be readily biomonitored. The correlation of Br in urine with 1-BP in air was also significant, but the r (about 0.7) was smaller than that for 1-BP, and the background Br level was also substantial (about 8 mg l-1). Thus, it was concluded that 1-BP in end-of-shift urine is a reliable biomarker of occupational exposure to 1-BP vapour, and that Br in urine is less reliable.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM NOTE RESEARCH ARTICLE WISTAR RAT MALE FEMALE 1-BROMOPROPANE TOXICOKINETICS TOXICITY HEPATIC METABOLISM PARTITION COEFFICIENT ANEMIA AMENORRHEA OLIGOSPERMIA HEPATIC MICROSOMES 2-BROMOPROPANE TOXICOLOGY BLOOD AND LYMPHATIC DISEASE REPRODUCTIVE SYSTEM DISEASE-FEMALE REPRODUCTIVE SYSTEM DISEASE-MALE KOREA PALEARCTIC REGION

Abstract  To investigate the effects on the central nervous system of subchronic exposure to 1-bromopropane (1-BP), which is a substitute for chlorofluorocarbons, we measured the hippocampal excitability of 1-BP-treated rats electrophysiologically. Male Wistar rats were exposed to 1-BP for 6-h in a day in an exposure chamber (1,500 ppm) for 4 wk. After the 1-, 3- and 4-wk inhalation, field excitatory postsynaptic potentials (fEPSPs), population spikes (PSs), fEPSP/spike (E/S) curve, paired-pulse profiles of fEPSP slopes and PS amplitudes recorded from CA1 pyramidal neurons, and dentate granule cells of the hippocampal slice obtained from the rats were analyzed. In 1-BP treated rats, E/S potentiation and a lower subthreshold of PSs were observed in the dentate gyrus (DG) after the 3 and 4-wk inhalation. Paired-pulse inhibition was reduced at 5-50 ms in the CA1 and at 5-20 ms in the DG after all of the inhalation. These changes were not associated with paired-pulse inhibition of fEPSPs. In the DG, the paired-pulse inhibition at the short interpulse intervals in rats exposed to 1-BP was pronounced by an application of A type gamma aminobutyric acid (GABA) receptor agonist pentobarbital. Impaired paired-pulse inhibition of granule cells at the short interpulse intervals was recovered after the application of N-methyl-D-aspartate (NMDA) type glutamate receptor antagonist DL-2-amino-5-phosphonopentanoic acid. Convulsing rats observed after the 4-wk inhalation exhibited multiple PSs in the DG, and their second component was abolished by an application of this antagonist. Inhalation of 1-BP increased the neuronal excitability in the hippocampal CA1 and the DG. The hyperexcitability of the granule cells in the DG was at least due to an over-activation of NMDA receptors.

Abstract  A Monte Carlo simulation using a diffusion based exposure assessment model was employed to aid forecasting of solvent vapour concentrations in the workspace during wipe cleaning of metal components. Range values for the important variables were chosen so as to be appropriated for wipe cleaning with either highly volatile solvents such as Vertrel-MCA or HFE71DE or with less volatile solvents such as n-propylbromide (nPBr). Emphasis is put on confirming that the range values of variables and the distributions taken are applicable to the workplace environment so that the simulation values obtained are reasonable estimates of the true vapour concentrations. The results obtained using Monte Carlo forecasts are considered most useful when taken in conjunction with the relevant occupational exposure limits for the solvents in question.

Abstract  In this study, a lipase from the liver of Cyprinus carpi Linnaeus (1758) living in Todurge Lake (Sivas) was purified with purification parameters of 90.38 mu mol/dk.mg protein specific activity and 75.50 fold purity. The purification procedure consisted of preparation of homogenate, precipitation with polyethylene glycol-6000 (PEG-6000) and chromatographic techniques including in Q sepharose, sephacryl S 200 HR and phenyl sepharose CL-4B, respectively. The purified lipase showed a single band with approximately a molecular weight of 74 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). pH and temperature optimums for the purified enzyme were determined as 8 and 37 degrees C using p-nitrophenyl butirate (p-NPB) as substrate. K-m and V-max values were found as 0.17 mM p-NPB and 2.6 mu mol/ml.dk, respectively. It was observed that surface active agents, such as sodium dodecyl sulfate (SDS), Triton X-100 and Nataurocholate act as inhibitor on lipase activity.

Abstract  Heterotrophic bacterial and phytoplankton biomass, production, specific growth rates, and growth efficiencies were studied in the Northern region of the Cananeia-Iguape estuarine system, which has recently experienced an intense eutrophication due to anthropogenic causes. Two surveys were carried out during spring and neap tide periods of the dry season of 2005 and the rainy season of 2006. This region receives large freshwater inputs with organic seston and phosphate concentrations that reach as high as 1.0 mg l(-1) and 20.0 mu M, respectively. Strong decreasing gradients of seston and dissolved inorganic nutrients were observed from the river/estuary boundary to the estuary/coastal interface. Gradients were also observed in phytoplankton and bacterial production rates. The production rates of phytoplankton were 5.6-fold higher (mean 8.5 mu g Cl(-1) h(-1)) during the dry season. Primary production rates (PP) positively correlated with salinity and euphoric depth, indicating that phytoplankton productivity was light-limited. On the other hand, bacterial biomass (BB) and production rates (BP) were 1.9- and 3.7-fold higher, respectively, during the rainy season, with mean values of up to 40.4 mu g Cl(-1) and 7.9 mu g Cl(-1) h-1, respectively. Despite such a high BP, bacterial abundance remained <2 x 106 cells ml(-1), indicating that bacterial production and removal were coupled. Mean specific growth rates ranged between 0.9 and 5.5 d(-1). BP was inversely correlated with salinity and positively correlated with temperature, organic matter, exopolymer particles, and particulate-attached bacteria; this last accounted for as much as 89.6% of the total abundance. During the rainy season, BP was generally much higher than PP, and values of BP/PP > 20 were registered during high freshwater input, suggesting that under these conditions, bacterial activity was predominantly supported by allochthonous inputs of organic carbon. In addition, BB probably represented the main pathway for the synthesis of high-quality (low C:N) biomass that may have been available to the heterotrophic components of the plankton food web, particularly nanoheterotrophs. (C) 2008 Elsevier Ltd. All rights reserved.

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  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  In this study, the properties of blue organic light-emitting diodes (OLEDs), employing quantum well-like structure (QWS) that includes four different blue emissive materials of 4,4'-bis(2,2'-diphenylyinyl)-1,1'-biphenyl (DPVBi), 9,10-di(naphth-2-yl)anthracene (ADN), 2-(N,N-diphenyl-amino)-6-[4-(N,N-diphenyl amine)styryl]naphthalene (DPASN), and bis(2-methyl-8-quinolinolate)-4-(phenyl phenolato) aluminum (BAlq), were investigated. Conventional QWS blue OLEDs composed of multiple emissive layers and charge blocking layer with lower highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy level, and devices with triple emissive layers for more significant hole-electron recombination and a wider region for exciton generation were designed. The properties of triple emissive layered blue OLEDs with the structure of indium tin oxide (ITO) /N,N'-diphenyl-N,N'-bis(1-naphthyl-phenyl)-(1,1'-biphenyl)-4,4'-diamine (NPB) (700 Ǻ)/X (100 Ǻ)/BAlq (100 Ǻ)/X (100 Ǻ)/4,7-diphenyl-1,10-phenanthroline (Bphen) (300 Ǻ)/lithium quinolate (Liq) (20 Ǻ)/aluminum (Al) (1,200 Ǻ) (X = DPVBi, ADN, DPASN) were examined. HOMO-LUMO energy levels of DPVBi, ADN, DPASN, and BAlq are 2.8 to 5.9, 2.6 to 5.6, 2.3 to 5.2, and 2.9 to 5.9 eV, respectively. The OLEDs with DPASN/BAlq/DPASN QWS with maximum luminous efficiency of 5.32 cd/A was achieved at 3.5 V.