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Sample records for 1-3-picolinium-12-triethylammonium-dodecane dibromide tmpd

  1. Discovery of a novel nicotinic receptor antagonist for the treatment of nicotine addiction: 1-(3-Picolinium)-12-triethylammonium-dodecane dibromide (TMPD).

    PubMed

    Dwoskin, Linda P; Joyce, B Matthew; Zheng, Guangrong; Neugebauer, Nichole M; Manda, Vamshi K; Lockman, Paul; Papke, Roger L; Bardo, Michael T; Crooks, Peter A

    2007-10-15

    Limitations in efficacy and high relapse rates of currently available smoking cessation agents reveal the need for more efficacious pharmacotherapies. One strategy is to develop subtype-selective nicotinic receptor (nAChR) antagonists that inhibit nicotine-evoked dopamine (DA) release, the primary neurotransmitter involved in nicotine reward. Simple alkylation of the pyridino N-atom converts nicotine from a potent agonist into a potent antagonist. The classical antagonists, hexamethonium and decamethonium, differentiate between peripheral nAChR subtypes. Using a similar approach, we interconnected varying quaternary ammonium moieties with a lipophilic linker to provide N,N'-bis-nicotinium analogs, affording a lead compound, N,N'-dodecyl-1,12-diyl-bis-3-picolinium dibromide (bPiDDB), which inhibited nicotine-evoked DA release and decreased nicotine self-administration. The current work describes a novel compound, 1-(3-picolinium)-12-triethylammonium-dodecane dibromide (TMPD), a hybrid of bPiDDB and decamethonium. TMPD completely inhibited (IC(50)=500 nM) nicotine-evoked DA release from superfused rat striatal slices, suggesting that TMPD acts as a nAChR antagonist at more than one subtype. TMPD (1 microM) inhibited the response to acetylcholine at alpha3beta4, alpha4beta4, alpha4beta2, and alpha1beta1varepsilondelta receptors expressed in Xenopus oocytes. TMPD had a 2-fold higher affinity than choline for the blood-brain barrier choline transporter, suggesting brain bioavailability. TMPD did not inhibit hyperactivity in nicotine sensitized rats, but significantly and specifically decreased nicotine self-administration. Together, the results suggest that TMPD may have the ability to reduce the rewarding effect of nicotine with minimal side effects, a pharmacological profile indicative of potential clinical utility for the treatment of tobacco dependence.

  2. Volatilization of ethylene dibromide from water

    USGS Publications Warehouse

    Rathbun, R.E.; Tai, D.Y.

    1987-01-01

    Overall mass-transfer coefficients for the volatilization of ethylene dibromide from water were measured simultaneously with the oxygen absorption coefficient in a laboratory stirred tank. Coefficients were measured as a function of mixing conditions in the water for two windspeeds. The ethylene dibromide mass-transfer coefficient depended on windspeed; the ethylene dibromide liquid-film coefficient did not, in agreement with theory. A constant relation existed between the liquid-film coefficients for ethylene dibromide and oxygen.

  3. The effects of diquat dibromide on biological wastewater treatment plants.

    PubMed

    Randall, C W; Cokgor, E U; Kisoglu, Z; Punrattanasin, W; Erdal, U; Sriwiriyarat, T

    2003-01-01

    The objective of the study was to investigate the fate and effects of diquat dibromide which is the active ingredient in formulations used to control the growth of roots into sewers when applied as Razorooter and mixed with raw sewage, settled sewage, and activated sludge, and when introduced into activated sludge wastewater treatment systems. Both fully aerobic and biological nutrient removal (BNR) activated sludge systems were used for experimental purpose, and both continuous flow and batch reactors were used. The sorption of diquat by both raw sewage particles and activated sludge suspended solids was determined. Diquat dibromide concentrations ranged from 0.93 to 12.6 mg/L in the influent flow. Both the fully aerobic and two full biological nutrient removal systems were fed municipal sewage spiked with diquat dibromide, and operated at a mixed liquor temperature of 10 degrees C and an MCRT of 10 days. One of the BNR systems was a control system. The results showed that only about 20% of the diquat in raw sewage flow was removed by adsorptions to the sewage solids, but 80% or more of the diquat was removed in activated sludge systems. When the influent diquat dibromide concentration was approximately 1mg/L, over 99% of the diquat dibromide was removed by the activated sludge process. Some of the removal was believed to be by biodegradation. The diquat dibromide used in this study had no observable detrimental effects on any of the biological processes of the continuous flow fully aerobic and BNR activated systems.

  4. Genetic effects of ethylene dibromide in Drosophila melanogaster

    SciTech Connect

    Kale, P.; Baum, J.W.

    1981-01-01

    Drosophila, an organism known to be one of the best among the available systems for mutation detection, can be used for detecting very low concentrations of airborne mutagens. Using ethylene dibromide (EDB), it was demonstrated that Drosophila could detect concentrations as low as 0.2 ppM in air when exposed for a relatively short period of 11 hrs. The exposure period can be prolonged to as many as 700 hrs using Drosophila. Response was proportional to integrated exposure in ppM-hr at low exposure values. It is, therefore, possible to detect airborne mutagens in the parts per billion range using proper germ cell stages in this system. Drosophila may, therefore, be used as a biological monitor to detect mutagenicity of air in polluted areas. Thus, the system may complement Tradescantia, another sensitive system being used for this purpose. Ethylene dibromide was selected as a test chemical in these studies since its mutagenic properties had previously been demonstrated in Drosophila and in Tradescantia. In Tradescantia, extensive data on the dose vs. mutation relation were available and these data were considered useful in evaluating the comparative sensitivity of the two systems for detecting airborne mutagens.

  5. Toxicity of carbaryl, diquat dibromide, and fluoranthene, individually and in mixture, to larval grass shrimp, Palaemonetes pugio.

    PubMed

    Chung, Katy W; Chandler, Allison R; Key, Peter B

    2008-05-01

    This study examined the toxicity of two pesticides (carbaryl and diquat dibromide) and one polycyclic aromatic hydrocarbon (fluoranthene), both singly and in mixture, to grass shrimp larvae (Palaemonetes pugio). These three chemicals are all present in coastal environments and can easily enter estuarine ecosystems. Fluoranthene was the most toxic chemical with a 96-h LC50 value of 32.45 microg/L, followed by carbaryl (43.02 microg/L) and diquat dibromide (1624 microg/L). In the chemical mixture tests, the binary carbaryl/diquat dibromide mixture and the ternary carbaryl/diquat dibromide/fluoranthene mixture had additive results.

  6. Semen study of papaya workers exposed to ethylene dibromide

    SciTech Connect

    Ratcliffe, J.M.; Schrader, S.M.; Steenland, K.; Clapp, D.; Turner, T.

    1984-01-01

    A cross sectional semen and cytogenetic study was performed on male workers exposed to ethylene-dibromide (EDB) in the papaya fumigation industry in Hawaii. Semen analyses were conducted on 46 men in six fumigation facilities with an average length of employment of 5 years and airborne exposures to EDB ranging from 16 to 213 parts per billion. Statistically significant decreases in sperm count per ejaculate and the percentage of viable and motile sperm and increases in the proportion of specific morphological abnormalities were observed among exposed men when compared with controls. Semen volume and sperm concentration were also lower in the exposed group. No effect of exposure to EDB on sperm velocity, the overall proportion of sperm with normal morphology or YFF bodies was noted. The authors conclude that based on the decreases in sperm count, viability and motility and increases in certain types of morphological abnormalities among workers exposed to EDB, EDB may increase the risk of reproductive impairment in workers at exposure levels near the NIOSH recommended limit of 45 parts per billion and far below the current OSHA standard of 20 parts per million.

  7. Dose-response studies with ethylene dibromide. [Hydra oligactis

    SciTech Connect

    Adams, J.A.

    1987-04-01

    This study represents the first of a series of Descriptive-Reproductive-Toxicology Studies currently underway in the authors laboratory. Ethylene Dibromide (EDB) is suspected of causing infertility (especially in males), carcinogenesis, mutagenesis, and possibly teratogenesis. Coupling the suspected undesirable effects of EDB exposure with the fact that the chemical has broad utility (soil fumigant, fruit and grain fumigant, gasoline additive, etc.), EDB is an important agricultural and industrial toxin. In this study Hydra oligactis are exposed to EDB in an attempt to determine the acute toxicity of the chemical. Since Hydra is organized at the tissue level only, the toxin can be applied as a component of an artificial pond water (APW) medium. The EDB stock solution is 19:1 Acetone (emulsifier): EDB. Direct dilutions are made and exposures are continuous. The medium is exchanged daily after feeding. The LC50 at 48 hours incubation with EDb is 70 mgL . Compared to the LC50's for two common commercial PCB mixtures, Aroclors 1254 and 1016, EDb is shown to be a highly toxic chemical. The respective LC50's for the PCB's are 20 mgL (Aroclor 1254) and 5 mgL (Aroclor 1016) at 72 hrs. Sublethal EDB toxicity is currently being studied.

  8. 75 FR 6658 - Malathion, Diquat Dibromide, Metam-potassium and Metam-sodium; Notice of Receipt of Requests to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-10

    ... AGENCY Malathion, Diquat Dibromide, Metam-potassium and Metam-sodium; Notice of Receipt of Requests to... registrations containing the pesticides malathion, diquat dibromide, metam-potassium, and metam-sodium. The... would terminate metam-sodium and metam- potassium soil fumigant uses (agricultural application) for...

  9. Development of an inhalation unit risk factor for ethylene dibromide.

    PubMed

    Schaefer, Heather R; Myers, Jessica L

    2017-09-11

    The Texas Commission on Environmental Quality (TCEQ) follows standard scientific methods to develop up-to-date toxicity factors for chemicals emitted in the state of Texas. An inhalation unit risk factor (URF) was developed for ethylene dibromide (EDB, CAS 106-93-4) based on an increased incidence of nasal cavity adenocarcinomas observed in female rats in a 2-year inhalation cancer bioassay conducted by the National Toxicology Program (NTP). The NTP study provided evidence of several EDB-induced tumors in male and female rats and in female mice. Tumor incidences that were statistically increased at the low dose and that showed a statistically significant increasing trend were considered in identifying the critical effect. Following benchmark concentration (BMC) modeling and animal-to-human dosimetric adjustments, the increased incidence of nasal cavity adenocarcinomas observed in female rats was determined to be the most sensitive tumorigenic effect in the most sensitive species and sex and was utilized as the carcinogenic endpoint for the development of the URF. The 95% lower confidence limit of the BMC at the 10% excess risk level (BMCL10 of 292.8 ppb) was determined for calculation of the URF. The resulting URF based on increased nasal cavity adenocarcinomas observed in female rats is 3.4E-04 per ppb (4.4E-05 per µg/m(3)). The lifetime air concentration corresponding to a no significant excess risk level of one in 100,000 is 0.029 ppb (0.22 µg/m(3)), which is considered sufficiently health-protective for use in protecting the general public against the potential carcinogenic effects of chronic exposure to EDB in ambient air.

  10. Differentiation of diastereotopic bromine atoms in SN2 reactions of gem-dibromides.

    PubMed

    Münster, Niels; Harms, Klaus; Koert, Ulrich

    2012-02-11

    A novel directed S(N)2 reaction of conformationally biased gem-dibromides and an arenesulfinate anion is described. The reaction results in the diastereoselective formation of α-bromosulfones. The selectivity originates from pre-coordination of the nucleophile to a free hydroxyl group in the γ-position.

  11. Anaerobic Biodegradation of Ethylene Dibromide and 1,2-Dichloroethane in the Presence of Fuel Hydrocarbons

    EPA Science Inventory

    Field evidence from underground storage tank sites where leaded gasoline leaked indicates the lead scavengers 1,2- dibromoethane (ethylene dibromide, or EDB) and 1,2- dichloroethane (1,2-DCA) may be present in groundwater at levels that pose unacceptable risk. These compounds are...

  12. Synthesis of an Advanced Intermediate of the Jatrophane Diterpene Pl-4: A Dibromide Coupling Approach

    PubMed Central

    2013-01-01

    The preparation of an advanced intermediate toward the synthesis of the jatrophane diterpene Pl-4 is described. The key step is a regioselective chelation-controlled lithiation of the (Z)-configured bromide in the corresponding vinyl dibromide precursor. The method outlined within this Article is suitable for the facile access of sterically hindered internal vinyl halides for further coupling reactions. PMID:23895274

  13. Anaerobic Biodegradation of Ethylene Dibromide and 1,2-Dichloroethane in the Presence of Fuel Hydrocarbons

    EPA Science Inventory

    Field evidence from underground storage tank sites where leaded gasoline leaked indicates the lead scavengers 1,2- dibromoethane (ethylene dibromide, or EDB) and 1,2- dichloroethane (1,2-DCA) may be present in groundwater at levels that pose unacceptable risk. These compounds are...

  14. Phosphorus-Containing Bis-allenes: Synthesis and Heterocyclization Reactions Mediated by Iodine or Copper Dibromide.

    PubMed

    Essid, I; Laborde, C; Legros, F; Sevrain, N; Touil, S; Rolland, M; Ayad, T; Volle, J-N; Pirat, J-L; Virieux, D

    2017-03-30

    Bisphosphorylallenes were easily obtained in multigram scale from the Wittig-type rearrangement of bispropargyl alcohols. Unlike other conjugated bis-allenes, these reagents underwent a double cyclization mediated by iodine or copper dibromide leading to the formation of bis-1,2-oxaphospholenes.

  15. 76 FR 27317 - Ziram, Diquat Dibromide, and Chloropicrin; Order for Amendments To Terminate Uses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-11

    ... (seed SL AG. crop only). 2749-531 Diquat Manufacturing Diquat Dibromide...... Sorghum and soybean (seed... seed beds using handheld fumigation devices. 8536-2 Chloropicrin 100 Chloropicrin Mushroom casing soil, Fumigant. potting soil, and small area seed beds using handheld fumigation devices. 8622-43 Metapicrin...

  16. Food contamination with styrene dibromide via packaging migration of leachate from polystyrene cold-storage insulation.

    PubMed

    Bendall, Justin G

    2007-04-01

    During distribution through an offshore transportation and cold-storage network, a multitonne consignment of cheese became contaminated, as apparent by a surface taint on some of the cheese blocks. Analysis of the volatile aroma compounds revealed that the taint was caused by styrene dibromide, estimated to be present in the tainted cheese at less than nanogram per gram concentrations. Condensed water, which had accumulated within the polystyrene insulation over a period of years, had been released by physical damage to the walls of an old cold store, and organic contaminants from the leached water had migrated through the packaging material of the cheese bags. Because styrene dibromide is toxic and mutagenic, its presence was intolerable in food intended for human consumption, and the consignment of cheese was ordered to be destroyed.

  17. Gas-film coefficients for the volatilization of ethylene dibromide from water

    USGS Publications Warehouse

    Rathbun, R.E.; Tal, D.Y.

    1986-01-01

    Gas-film coefficients for the volatilization of ethylene dibromide (EDB) and water were determined in the laboratory as a function of wind speed and temperature. The ratio of the coefficients was independent of wind speed and increased slightly with temperature. Use of this ratio with an environmentally determined gas-film coefficient for the evaporation of water permits determination of the gas-film coefficient for the volatilization of EDB from environmental waters.

  18. Efficacy of pentane, toluene, and benzene to support aerobic cometabolism of ethylene dibromide.

    PubMed

    Danko, Anthony S; Leitão, Patrícia O; Verce, Matthew F; Freedman, David L

    2012-11-15

    The ability of pentane, benzene, and toluene to support aerobic cometabolism of ethylene dibromide (1,2-dibromoethane, EDB) was evaluated. A pentane enrichment culture cometabolized EDB, with a transformation capacity of 0.35 μmol EDB/mg biomass (66.2 μg EDB/mg biomass) in the absence of growth substrate. It also cometabolized EDB while actively growing on pentane. However, enrichment cultures grown on benzene or toluene could not cometabolize EDB, with or without their respective growth substrates. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Induction of delayed mutations by benzene and ethylene dibromide in drosophila

    SciTech Connect

    Kale, P.; Kale, R.

    1995-08-01

    Two carcinogens, ethylene dibromide and benzene, were used to induce delayed (germinal mosaic) sex-linked recessive lethal mutations in spermatozoa and spermatids of adult Drosophila males. Significant numbers of delayed mutations (in F{sub 3}) were scored in absence of conventional (in F{sub 2}) mutations. A large proportion of nonlethal F{sub 2} cultures carried delayed mutations, so much so that, in some cultures, all F{sub 2} females were carriers of mutations. The mechanism through which single strand damage to treated X chromosomes can result in such delayed lethals is discussed. These observations indicate that the delayed mutation test should be used for testing the mutagenicity of environmental compounds, especially carcinogens, which tested negative in the conventional sex-linked recessive lethal mutation test. The data will support the relationship between mutagenesis and carcinogenesis and, also will further enhance the sensitivity of the Drosophila mutation assay. 12 refs., 4 tabs.

  20. On-Surface Formation of Cumulene by Dehalogenative Homocoupling of Alkenyl gem-Dibromides.

    PubMed

    Sun, Qiang; Tran, Bay V; Cai, Liangliang; Ma, Honghong; Yu, Xin; Yuan, Chunxue; Stöhr, Meike; Xu, Wei

    2017-09-25

    The on-surface activation of carbon-halogen groups is an efficient route to produce radicals for constructing various hydrocarbons and carbon nanostructures. To date, the employed halide precursors have only one halogen attached to a carbon atom. It is thus of interest to study the effect of attaching more than one halogen atom to a carbon atom with the aim of producing multiple unpaired electrons. By introducing an alkenyl gem-dibromide, cumulene products were fabricated on a Au(111) surface by dehalogenative homocoupling reactions. The reaction products and pathways were unambiguously characterized by a combination of high-resolution scanning tunneling microscopy and non-contact atomic force microscopy measurements together with density functional calculations. This study further supplements the database of on-surface synthesis strategies and provides a facile manner for incorporation of more complicated carbon scaffolds into surface nanostructures. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Ethylene dibromide: Biochemical effects and environmental concerns. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1993-05-01

    The bibliography contains citations concerning the toxicity and environmental issues pertaining to the fumigant ethylene dibromide. Topics include effects on liver activity, respiratory systems and DNA synthesis in laboratory animals, comparisons and synergistic effects with other pesticides, and occupational health considerations. The distribution of the compound in the environment and its effectiveness as a fumigant are also considered. (Contains a minimum of 100 citations and includes a subject term index and title list.)

  2. Effects of ethylene dibromide on hydra oligactis: parent and offspring toxicity study

    SciTech Connect

    Wilson, B.A.; Adams, J.A.

    1988-04-01

    Ethylene Dibromide (EDB) has become increasingly prevalent in the environment due to its uses as soil, fruit, and grain fumigants, lead scavengers in petrol, and industrial solvent. Because of its increasing environmental prevalence and its proposed toxic effects of EDB on Hydras, parents (P1) which have been pre-exposed to an established sublethal concentration for 14 days. The effect of nonexposed offspring (F1/P2) taken from pre-exposed parents (P1) versus their untreated offspring (F2) will also be evaluated. This mortality study revealed that the LC50 of both parents and F1's shifted from 50 mg/L, to 106.25 mg/L and 118.75 mg/L respectively, which suggest that exposed Hydras possibly become more tolerant to EDB. In the F2 generation, after 48 and 72 hrs 10% mortality was observed in the 200 mg/L group, 30% at 250 mg/L and 20% at 300 mg/L which indicated that the resistance to EDB toxicity is inheritable. There is also a strong dose-response correlation between EDB concentration and mortality.

  3. Dual Carbon-Bromine Stable Isotope Analysis Allows Distinguishing Transformation Pathways of Ethylene Dibromide.

    PubMed

    Kuntze, Kevin; Kozell, Anna; Richnow, Hans H; Halicz, Ludwik; Nijenhuis, Ivonne; Gelman, Faina

    2016-09-20

    The present study investigated dual carbon-bromine isotope fractionation of the common groundwater contaminant ethylene dibromide (EDB) during chemical and biological transformations, including aerobic and anaerobic biodegradation, alkaline hydrolysis, Fenton-like degradation, debromination by Zn(0) and reduced corrinoids. Significantly different correlation of carbon and bromine isotope fractionation (ΛC/Br) was observed not only for the processes following different transformation pathways, but also for abiotic and biotic processes with, the presumed, same formal chemical degradation mechanism. The studied processes resulted in a wide range of ΛC/Br values: ΛC/Br = 30.1 was observed for hydrolysis of EDB in alkaline solution; ΛC/Br between 4.2 and 5.3 were determined for dibromoelimination pathway with reduced corrinoids and Zn(0) particles; EDB biodegradation by Ancylobacter aquaticus and Sulfurospirillum multivorans resulted in ΛC/Br = 10.7 and 2.4, respectively; Fenton-like degradation resulted in carbon isotope fractionation only, leading to ΛC/Br ∞. Calculated carbon apparent kinetic isotope effects ((13)C-AKIE) fell with 1.005 to 1.035 within expected ranges according to the theoretical KIE, however, biotic transformations resulted in weaker carbon isotope effects than respective abiotic transformations. Relatively large bromine isotope effects with (81)Br-AKIE of 1.0012-1.002 and 1.0021-1.004 were observed for nucleophilic substitution and dibromoelimination, respectively, and reveal so far underestimated strong bromine isotope effects.

  4. Semen quality in papaya workers with long term exposure to ethylene dibromide.

    PubMed Central

    Ratcliffe, J M; Schrader, S M; Steenland, K; Clapp, D E; Turner, T; Hornung, R W

    1987-01-01

    To examine whether long term occupational exposure to ethylene dibromide (EDB) affects semen quality a cross sectional study of semen quality was conducted among 46 men employed in the papaya fumigation industry in Hawaii, with an average duration of exposure of five years and a geometric mean breathing zone exposure to airborne EDB of 88 ppb (eight hour time weighted average) and peak exposures of up to 262 ppb. The comparison group consisted of 43 unexposed men from a nearby sugar refinery. Statistically significant decreases in sperm count per ejaculate, the percentage of viable and motile sperm, and increases in the proportion of sperm with specific morphological abnormalities (tapered heads, absent heads, and abnormal tails) were observed among exposed men by comparison with controls after consideration of smoking, caffeine and alcohol consumption, subject's age, abstinence, history of urogenital disorders, and other potentially confounding variables. No effect of exposure to EDB on sperm velocity, the overall proportion of sperm with normal morphology, or YFF bodies was observed. These data strongly suggest that EDB may increase the risk of reproductive impairment in workers at exposure levels near the National Institute for Occupational Safety and Health recommended limit of 45 ppb (as an eight hour time weighted average) and far below the current standard of the Occupational Safety and Health Administration of 20 ppm. PMID:3297130

  5. Structure, spectroscopy and DFT calculations of 1,2-di(3-hydroxymethylpyridinium)ethane dibromide

    NASA Astrophysics Data System (ADS)

    Komasa, Anna; Barczyński, Piotr; Ratajczak-Sitarz, Małgorzata; Katrusiak, Andrzej; Dega-Szafran, Zofia; Szafran, Mirosław

    2016-09-01

    The molecular structure of 1,2-di(3-hydroxymethylpyridinium)ethane dibromide (1) has been characterized by X-ray diffraction, B3LYP/6-311++G(d,p) calculations, FTIR, Raman and NMR spectra. The crystals are monoclinic, space group C2/c. 1,2-Di(3-hydroxymethylpyridinium)ethane dication and hydrogen-bonded bromide anions in crystals are located at the inversion center. The both CH2OH groups are engaged in two equal length hydrogen bonds with bromide anions. Two structures (2) and (3) were optimized at the B3LYP/6-311++G(d,p) level of theory. The optimized complex (2) resembles the crystal structure, while complex (3) is preferred energetically. The O⋯Br- hydrogen bonds distances are: 3.289(2) Å in crystals (1), but in the optimized structures (2) and (3) they are 3.303 Å and 3.461 Å, respectively. The investigated complex is additionally stabilized by the N+⋯Br- electrostatic attractions. The potential energy distributions (PED) were used for the assignments of IR and Raman frequencies in the experimental and calculated spectra of the title compound. The FTIR spectrum of (1) is consistent with the X-ray results. Interpretation of the 1H and 13C NMR spectra in DMSO-d6 has been based on 2D experiments. The calculated GIAO/B3LYP/6-311++G(d,p) magnetic shielding constants have been used to predict 1H and 13C chemical shifts for the optimized structures of (2) and (3).

  6. Movement and fate of ethylene dibromide (EDB) in ground water in Seminole County, Georgia

    USGS Publications Warehouse

    McConnell, J.B.

    1987-01-01

    An investigation to assess the movement and fate of ethylene dibromide (EDB) in the Upper Floridan aquifer (formerly the principal artesian aquifer) was conducted, because a previous investigation conducted in August 1983, had found EDB contamination of the aquifer in about a 4 sq mi area in central Seminole County, Georgia. Analyses of water from wells resampled in June 1985 indicate that EDB was present in the groundwater 2 yr after last being applied as a soil fumigant. The investigation revealed that groundwater recharge and irrigation pumping between August 1983 and June 1985 did not substantially change the areal extent of EDB in the Upper Floridan aquifer but concentrations of EDB seem to be declining. The highest concentrations again were found in two irrigation wells near Buck Hole, a sinkhole in a swampy depression in central Seminole County. EDB concentrations in these two wells ranged from 1.5 to 13 micrograms/L. Samples from two of three wells in the residuum near Buck Hole also had detectable concentrations of EDB. The presence of EDB in water samples from wells tapping the residuum and wells tapping the Upper Floridan aquifer indicates that agriculturally applied EDB has moved downward from the surface soils through the residuum and into the aquifer. Results of aquifer tests conducted in a similar geohydrologic setting suggest that local pumping from the highly transmissive aquifer may accelerate downward movement of water and EDB. Potentiometric surface maps of the Upper Floridan aquifer indicate that east of Fishpond Drain, where the highest concentrations of EDB were detected, the direction of groundwater flow and the direction of potential EDB transport generally is south-southeasterly. However, the movement of an EDB plume from the area of relatively high concentrations near Buck Hole along inferred groundwater flow lines was not detected. (Author 's abstract)

  7. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    SciTech Connect

    Malinina, A. A. Malinin, A. N.

    2015-03-15

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ{sub max} = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10{sup −15} m{sup 3}/s.

  8. Forestomach lesions induced by butylated hydroxyanisole and ethylene dibromide: a scientific and regulatory perspective.

    PubMed

    Moch, R W

    1988-01-01

    Selected pathology lesions from 9 studies, 5 with butylated hydroxyanisole (BHA) and 4 with ethylene dibromide (EDB) are reviewed and their relative importance in regulatory evaluation is discussed. When Fischer 344 (F344) rats were fed BHA at 0.5% and 2.0% of the diet for 2 years, an increased number of rats of both sexes had epithelial hyperplasia of the forestomach at both treatment levels, compared to controls. At the 2.0% level, an increased number of rats had forestomach papilloma or forestomach squamous cell carcinoma. In a second study, in which F344 rats were fed BHA at 1.0% and 2.0% of the diet for 2 years, increased numbers of rats in both treatment groups were reported to have hyperplasia or papilloma of the forestomach. At the 2.0% level, increased numbers of rats developed squamous cell carcinoma of the forestomach. More Syrian golden hamsters fed BHA at 1.0% and 2.0% of the diet for 2 years reportedly had hyperplasia, papilloma or squamous cell carcinoma of the forestomach than did nontreated animals. Ingestion of BHA at 0.5% and 1.0% of the diet by B6C3F1 mice for 2 years was reported to produce an increase of animals with hyperplasia or papilloma of the forestomach at both dosage levels, compared to nontreated mice. When beagle dogs were fed BHA at 1.0% and 1.3% of the diet for 180 days, no lesions/tumors of the distal esophagus or stomach were identified at gross necropsy or by light or electron microscopy. When EDB was administered by gavage to Osborne-Mendel rats and B6C3F1 mice under conditions of the National Toxicology Bioassay Program, more rats and mice, both male and female, developed squamous cell carcinoma of the forestomach than did nontreated groups. EDB administered via inhalation to F344 rats and B6C3F1 mice did not cause squamous cell carcinoma of the forestomach; however, other neoplasms occurred which were considered to be treatment-related. Information gleaned from the BHA and EDB studies with multiple animal species facilitated

  9. Investigation of ethylene dibromide (EDB) in ground water in Seminole County, Georgia

    USGS Publications Warehouse

    McConnell, James B.; Hicks, D.W.; Lowe, L. E.; Cohen, S.Z.; Jovanovich, A.P.

    1984-01-01

    An investigation of ground water in Seminole County, Georgia, for ethylene dibromide (EDB) was conducted in August 1983 by the U.S. Geological Survey in cooperation with the Exposure Assessment Branch of the U.S. Environmental Protection Agency. The purpose of the investigation was to determine whether EDB, which was previously detected in ground-water samples from four neighboring wells, was localized in the vicinity of the wells or was more widespread in the ground-water system. EDB was detected in 6 of 19 wells sampled. Concentrations ranged from 0.03 to 11.8 micrograms per liter. Five of the six samples that contained EDB were collected from irrigation wells, and one was collected from a domestic well. Concentrations of 4.5 and 11.8 micrograms per liter were found in two irrigation wells located near Buck Hole, a sinkhole in a swampy depression in central Seminole County. EDB was not detected in samples from the remaining 10 irrigation and 3 domestic wells and the surface-water site (detection level less than 0.01 microgram per liter). Nine core samples were collected from a borehole near one of the irrigation wells that had high EDB concentrations. EDB was found in a core sample near the surface and in samples from depths of 24 to 25, 34 to 35, and 39 to 40 feet in the residuum. EDB concentrations in the core samples ranged from 0.06 to 2.4 micrograms per kilogram. EDB in the aquifer was found in a 4-square-mile area of the county in the vicinity of Buck Hole. EDB application information and the local hydrogeology indicate that EDB contamination in ground water in Seminole County probably is due to soil fumigation with EDB. Apparently, EDB moves downward through the residuum and, through undetermined pathways, enters the aquifer. However, because the high concentration of EDB in the aquifer seems to be localized in the Buck Hole area, the possibility of contamination from an EDB fumigant spill cannot be disregarded at this time.

  10. Acute Intramuscular Toxicity (LD50) of 1,1’-Methylenebis (4- (Hydroxyimino) Methyl) Pyridinium Dibromide, (MMB-4) in Male Mice

    DTIC Science & Technology

    1983-04-01

    METHODS Test Substance Chemical name: 1,1 ’-Methylenebis[4-[(hydroxyimino) methyl] pyridinium] dibromide, (01MB-4) (TAO03) Chemical Abstract Service...name: 1,1 ’-Methylenebis[4-[(hydroxyimino)methyl] pyridiniumldibromide, (CMIB-1 𔃾 Chemical Abstract Service Registry Number: None Molecular formula

  11. Industrial-hygiene report, walk-through survey, papaya packing/shipping facilities, Hilo, Hawaii, July 1983. [Ethylene dibromide exposure

    SciTech Connect

    Clapp, D.

    1983-07-01

    Worker exposure to ethylene dibromide (EDB) was investigated at three papaya packing and shipping facilities in Hilo, Hawaii. Breathing-zone samples were collected in the three facilities over a three day period. Blind spikes were submitted as a control on time and temperature effects. Blank samples were also prepared. Spike results reflected the effects of time and temperature in shipment from Hawaii to Massachusetts. All spikes were roughly comparable and showed a recovery of about 68%. Overnight laboratory results were adjusted upward by 72% and NIOSH laboratory results by 68%. Six out of 38 samples exceeded the NIOSH recommended amount of 130 ppb. The author concludes that there is a chronic, low-concentration exposure to EDB for all workers in the papaya industry in Hilo. An epidemiological study of reproductive and cytogenetic effects of EDB exposure on these workers is recommended.

  12. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    SciTech Connect

    Malinina, A. A. Malinin, A. N.

    2013-12-15

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10{sup −14} m{sup 3}/s for a reduced electric field of E/N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λ{sub max} = 502 nm) was observed in this experiment.

  13. Spectral characteristics of a broadband exciplex spontaneous emission source upon mixtures of the cadmium dibromide vapor with gases

    NASA Astrophysics Data System (ADS)

    Guivan, M. M.; Malinin, A. N.

    2007-03-01

    The spectral characteristics of radiation from atmospheric-pressure gas-discharge plasma in mixtures of cadmium dibromide vapor with gases (Ne, Ar, Kr, Xe, and N2), as well as the temporal characteristics of the voltage and current, have been investigated. A barrier discharge at the repetition frequency of sine voltage pulses up to 140 kHz has been used to create the gas-discharge plasma and excite the components of the working mixture. The discharge radiation has been analyzed in the spectral range 200-900 nm with a high resolution (0.05 nm). In the spectra, we have revealed radiation from exciplex molecules CdBr( B → X) and CdBr( C → X), atomic lines of cadmium and inert gases, and, in mixtures with xenon, radiation of exciplex molecules XeBr( B → X, B → A). The XeBr( B → X) radiation prevailed in the spectra at mixture temperatures up to 200°C. The further increase of the temperature resulted in the prevalence of the CdBr( B → X) radiation. The most intense CdBr( B → X) radiation was observed in mixtures of CdBr2/Xe. When the temperature of the mixture was higher than 250°C, the discharge radiation had a silvery-white color. Regularities in the spectral characteristics of the radiation from the gas-discharge plasma are discussed. The high-frequency atmospheric-pressure barrier discharge in mixtures of cadmium dibromide with gases, excited by sine voltage pulses, can be used in multiwave and broadband excilamps, operating in the UV and visible regions.

  14. Dexamethasone inhibits induction of liver tumor necrosis factor-alpha mRNA and liver growth induced by lead nitrate and ethylene dibromide.

    PubMed Central

    Ledda-Columbano, G. M.; Columbano, A.; Cannas, A.; Simbula, G.; Okita, K.; Kayano, K.; Kubo, Y.; Katyal, S. L.; Shinozuka, H.

    1994-01-01

    We have recently demonstrated that a single injection of the mitogen lead nitrate to rats induced a rapid increase of tumor necrosis factor-alpha (TNF-alpha) mRNA in the liver and suggested that this cytokine may be involved in triggering hepatocyte proliferation in this model of direct hyperplasia. In this study, we examined whether a similar induction of liver TNF-alpha mRNA could be observed preceding the onset of hepatocyte proliferation induced by ethylene dibromide, another hepatocyte mitogen. In addition, we used dexamethasone, a well known inhibitor of TNF-alpha production, to determine whether its administration could suppress hepatocyte proliferation induced by lead nitrate and ethylene dibromide. A single intragastric administration of ethylene dibromide (100 mg/kg) to male Wistar rats enhanced liver TNF-alpha mRNA after 4 and 7 hours, which then returned to control levels by 24 hours. TNF-alpha mRNA was detectable only in a nonparenchymal cell fraction of the liver. Pretreatment of rats with a single dose of dexamethasone (2 mg/kg) 60 minutes before lead nitrate (100 mumol/kg) or ethylene dibromide completely abolished the increased levels of liver TNF-alpha mRNA induced by these agents. Inhibition by dexamethasone of TNF-alpha mRNA was associated with an inhibition of liver cell proliferation induced by these mitogens, as measured by [3H]thymidine incorporation into hepatic DNA, mitotic index, and DNA content. These results further support the hypothesis that TNF-alpha may be involved in triggering hepatocyte proliferation induced by primary mitogens. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:7943184

  15. Real-time analysis of diaquat dibromide monohydrate in water with a SERS-based integrated microdroplet sensor

    NASA Astrophysics Data System (ADS)

    Gao, Rongke; Choi, Namhyun; Chang, Soo-Ik; Lee, Eun Kyu; Choo, Jaebum

    2014-07-01

    We report the fast and sensitive trace analysis of diaquat dibromide monohydrate (DQ) in water using a surface-enhanced Raman scattering (SERS)-based microdroplet sensor. This sensor is composed of two compartments: the first one is for droplet generation for fresh silver nanoparticle (AgNP) synthesis and the second for droplet merging for SERS detection. Silver ions were nucleated and grown to large size AgNPs in droplets, and then each droplet was synchronously merged with another droplet containing DQ for SERS detection. This two-phase liquid-liquid segmented flow system prevented memory effects caused by the precipitation of nanoparticle aggregates on channel walls because the aqueous droplets were isolated by a continuous oil phase. The limit of detection (LOD) of DQ in water was determined to be below 5 nM, which satisfies the maximum contaminant level defined by the United States EPA. This method was also validated successfully in DQ-spiked tap water. The SERS-based integrated sensing system is expected to be useful as an in-the-field sensing platform for fast and reproducible trace analysis of environmental pollutants in water.We report the fast and sensitive trace analysis of diaquat dibromide monohydrate (DQ) in water using a surface-enhanced Raman scattering (SERS)-based microdroplet sensor. This sensor is composed of two compartments: the first one is for droplet generation for fresh silver nanoparticle (AgNP) synthesis and the second for droplet merging for SERS detection. Silver ions were nucleated and grown to large size AgNPs in droplets, and then each droplet was synchronously merged with another droplet containing DQ for SERS detection. This two-phase liquid-liquid segmented flow system prevented memory effects caused by the precipitation of nanoparticle aggregates on channel walls because the aqueous droplets were isolated by a continuous oil phase. The limit of detection (LOD) of DQ in water was determined to be below 5 nM, which satisfies the

  16. Ethylene dibromide and disulfiram: studies in vivo and in vitro on the mechanism of the observed synergistic carcinogenic response.

    PubMed

    Elliott, B M; Ashby, J

    1980-01-01

    Two possible mechanisms for the reported carcinogenic synergism between ethylene dibromide (EDB) and disulfiram have been investigated in vivo and in vitro, the first involving increased production of an EDB-derived glutathione mustard and the second increased production of bromoacetaldehyde. Consistent with both of these suggested mechanisms, repeated administrations of disulfiram to rats inreased liver glutathione-S-transferase activity and decreased liver low Km aldehyde dehydrogenase activity. However, when added to a rat liver S-9 fraction in vitro, disulfiram decreased transferase activity and only depressed the dehydrogenase activity after a period of preincubation. Although the mutagenic potency of EDB to Salmonella typhimurium was slightly enhanced in vitro by the addition of a rat liver S-9 fraction, the further addition of disulfiram to the assay medium produced no additional change. Similarly, the addition of a range of S-9 and S-0.5 liver fractions derived from disulfiram-treated rats also failed to enhance significantly its mutagenic potency over the normal S-9 fraction. The general implications of these findings are discussed.

  17. Contamination of groundwater by the fumigants ethylene dibromide (EDB) and dibromochloropropane (DBCP) near McBee, South Carolina

    USGS Publications Warehouse

    Landmeyer, James E.; Campbell, Bruce G.

    2010-01-01

    McBee is a small town of about 700 people located in Chesterfield County, South Carolina, in the Sandhills region of the upper Coastal Plain. The halogenated organic compounds ethylene dibromide (EDB) and dibromochloropropane (DBCP) have been detected in several public and domestic supply and irrigation wells since 2002 at concentrations above their U.S. Environmental Protection Agency Maximum Contaminant Limits of 0.05 and 0.2 microgram per liter (µg/L), respectively. The source(s) and release histories of EDB and DBCP to local groundwater are unknown, but believed to be related to their historical use between the 1940s and their ban in the late 1970s as fumigants to control nematode damage in peach orchards. However, gasoline and jet-fuel supplies also contained EDB and are an alternative source of contamination to groundwater. The detection of EDB and DBCP in water wells has raised health concerns because groundwater is the sole source of water supply in the McBee area. In April 2010, forensic, geochemical-based investigation was initiated by the U.S. Geological Survey in cooperation with the Alligator Rural Water & Sewer Company to provide additional data regarding EDB and DBCP in local groundwater. The investigation includes an assessment of the use, release, and disposal history of EDB and DBCP in the area, the distribution of EDB and DBCP concentrations in the unsaturated zone, and transport and fate in groundwater.

  18. Study on the bindings of dichlorprop and diquat dibromide herbicides to human serum albumin by spectroscopic methods.

    PubMed

    Tunç, Sibel; Duman, Osman; Soylu, Inanç; Kancı Bozoğlan, Bahar

    2014-05-30

    The interactions of dichlorprop (DCP) and diquat dibromide (DQ) herbicides with human serum albumin (HSA) protein were studied by UV absorption, fluorescence, synchronous fluorescence and circular dichroism (CD) spectroscopy. Both DCP and DQ quenched the fluorescence emission spectrum of HSA through the static quenching mechanism. The Stern-Volmer quenching constant, binding constant, the number of binding sites and thermodynamic parameters were determined at 288K, 298K, 310K and 318K. In HSA-DCP and HSA-DQ systems, an increase in temperature led to a decrease in the Stern-Volmer quenching constant and binding constant. One binding site was obtained for DCP and DQ on HSA. It was found that DCP can bind to HSA with higher affinity than DQ. Negative ΔH and positive ΔS values were obtained for the binding processes between protein and herbicide molecules. This result displayed that electrostatic interactions play a major role in the formation of HSA-DCP and HSA-DQ complexes. The binding processes were exothermic reactions and spontaneous. In addition, synchronous fluorescence and CD spectra of HSA revealed that the binding of DCP to HSA did not cause a significant conformational change in protein, but the interaction of DQ with HSA led to an alteration in the protein structure. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Ethylene dibromide (EDB) trends in the upper Floridan Aquifer, Seminole County, Georgia, October 1981 to November 1987

    USGS Publications Warehouse

    McConnell, J.B.

    1988-01-01

    Results of an investigation to assess the persistence and trends of ethylene dibromide (EDB) in the Upper Floridan aquifer, in Georgia indicate that in November 1987, EDB was present in the groundwater 4 years after it was last applied as a soil fumigant in the intensively farmed area of central Seminole County. At that time, EDB was detected in water samples from one domestic well and four irrigation wells. Concentrations ranged from less than 0.01 micrograms/L to 3.3 micrograms/L. The investigation in November 1987 revealed the groundwater contamination was limited to the 4-sq-mi area in the vicinity of Buck Hole, a sinkhole in a swampy depression in the central part of the County. In three of the five wells in which EDB was detected, concentrations have not changed significantly since August 1983. However, in one irrigation well near Buck Hole, the concentration decreased from 110 to 0.7 microgram/L since October 1981. In another irrigation well near Buck Hole, the concentration decreased from 26 to about 2.5 microgram/L during that period. The groundwater level data indicate that from Buck Hole, the hydraulic gradient in the Upper Floridan aquifer is about 2.8 ft/mi toward the east. However, the movement of EDB from the area of relatively high concentration near Buck Hole in the direction of inferred flow lines is not apparent. Although concentration gradients were not detected along flow lines, the movement of water induced by pumping wells W4 and W5 produced short-term decreasing and increasing trends in EDB Concentrations in wells W4 and W5, respectively. (USGS)

  20. Undetected Groundwater Contamination at Underground Storage Tank Sites by the Gasoline Lead Scavengers Ethylene Dibromide and 1,2-Dichloroethane

    NASA Astrophysics Data System (ADS)

    Falta, R. W.

    2004-05-01

    Ethylene dibromide (EDB) is a synthetic organic chemical that was produced in large amounts for use as a leaded gasoline additive and pesticide. The chlorinated solvent 1,2-dichlorethane (1,2-DCA) is widely used in the chemical industry, and was also added to leaded gasoline. EDB and 1,2-DCA are classified as probable human carcinogens by the United States Environmental Protection Agency (EPA), and EDB's use as a pesticide was suspended in 1984. The current EPA maximum contaminant level (MCL) for EDB in drinking water is 0.05 ug/l, and the MCL for 1,2-DCA is 5 ug/l. EDB has proven to be both mobile and persistent in groundwater, and contamination of groundwater by EDB was documented in several states beginning in the early 1980s. The majority of this contamination is attributed to agricultural uses of EDB, however approximately 90 percent of the EDB produced was used as a leaded gasoline additive, and it was present in virtually all leaded gasoline sold in the US. 1,2-DCA is commonly found as a groundwater contaminant, and it is both mobile and persistent. Past site investigations and remediation efforts at underground storage tank sites contaminated by leaded gasoline have rarely addressed the potential for EDB or 1,2-DCA contamination. However, the concentrations of EDB and 1,2-DCA in leaded gasoline were high enough to produce groundwater concentrations of thousands of ug/l. For this reason, there is a substantial likelihood that undetected EDB and 1,2-DCA plumes above the MCL may exist at many sites where leaded gasoline leaked or spilled. An initial review of field data from underground storage tank sites in two states suggests that this problem is widespread.

  1. Emission of mercury monobromide exciplex in gas-discharge plasma based on mixture of mercury dibromide vapor with sulfur hexafluoride and helium

    NASA Astrophysics Data System (ADS)

    Malinina, A. A.; Shuaibov, A. K.

    2011-02-01

    We present the results of investigations of an emission of a mercury monobromide exciplex in gas-discharge plasma of an atmospheric pressure barrier discharge based on a mixture of mercury dibromide vapor, sulfur hexafluoride, and helium. We optimized the emission power of mercury monobromide exciplexes with respect to the partial pressures of the working mixture. An average emission power of 0.42 W (λmax = 502 nm) is achieved in a cylindrical emission source with a small working volume (0.8 cm3) at a pumping pulse repetition rate of 6 kHz. We determined electron energy distribution functions, transport characteristics, specific discharge power losses for electron processes, electron concentration and temperature, as well as rate constants of elastic and inelastic scattering of electrons by components of the working mixture in relation to the ratio of the field strength to the total concentration of components of the working mixture. We discuss processes that increase the population of the mercury monobromide exciplex. Gas-discharge plasma created in a mixture of mercury dibromide vapor with sulfur hexafluoride and helium can be used as a working medium of an emission source in the blue-green spectral range for the use in scientific research in biotechnology, photonics, and medicine, as well as for creating indicator gas-discharge panels.

  2. Improving the understanding of DNA-propanediyl-1,3-bis(dodecyldimethylammonium) dibromide interaction using thermodynamic, structural and kinetic approaches.

    PubMed

    Grueso, Elia; Kuliszewska, Edyta; Prado-Gotor, Rafael; Perez-Tejeda, Pilar; Roldan, Emilio

    2013-12-14

    A kinetic, thermodynamic and structural study of the interaction of the gemini surfactant propanediyl-1,3-bis(dimethyldodecylammonium dibromide) (12-3-12.2Br) with calf thymus DNA was carried out at several ionic strengths (NaCl) in aqueous solutions. A new 12-3-12(2+)-selective membrane was prepared in order to gain insight into the factors that control the binding of 12-3-12.2Br to DNA. We used ethidium bromide (EB) as a fluorescence probe to follow the kinetics of the interaction by using the stopped-flow fluorescence technique. The results can be explained in terms of a reaction mechanism involving two consecutive reversible (fast and slow) steps. The fast step was attributed to the union/separation of the surfactant with/from the DNA polynucleotide. Changes in the kinetic constants in the forward and backward directions were discussed in terms of the Brönsted-Pitzer equation and of the increase in hydrophobic interactions of the surfactant tails as a consequence of salting-out effects, respectively. The slow step corresponds to a conformational change of the surfactant-DNA complex to a more compacted form. The equilibrium constant, calculated from the forward and reverse rate constants of these steps, agrees with the results obtained from potentiometric titration using a 12-3-12-(2+) selective electrode.

  3. Use of new field methods of semen analysis in the study of occupational hazards to reproduction: the example of ethylene dibromide

    SciTech Connect

    Schrader, S.M.; Ratcliffe, J.M.; Turner, T.W.; Hornung, R.W.

    1987-12-01

    Increasing attention has been paid to the use of semen analysis as an indicator of exposure to potential mutagenic and reproductive hazards. In the infertility clinic setting, semen evaluations include the measurement of sperm concentration, volume, pH, motility, velocity and morphology, the analysis of seminal plasma to evaluate accessory sex gland function and, in some cases, the in vitro evaluation of fertilization capacity and sperm-cervical mucus interaction. To date, however, the study of semen characteristics of occupationally exposed populations has been confined principally to the measurement of sperm concentration and sperm morphology. This has been largely due to the unavailability of portable equipment suitable for the measurement of other semen characteristics and the difficulty of obtaining fresh semen samples in the field setting. National Institute for Occupational Safety and Health researchers have developed mobile laboratory facilities which enable us to evaluate fresh samples, in the field, for semen characteristics in addition to concentration and morphology. This paper describes the application of these methods using the example of our recent cross-sectional study of workers occupationally exposed to ethylene dibromide in the papaya fumigation industry. We discuss our findings in the context of the usefulness of semen analysis as an indicator of occupational hazards to male reproduction.

  4. 1,2 Dibromo-3-chloropropane (DBCP) and ethylene dibromide (EDB) in well water in the Fresno/Clovis metropolitan area, California.

    PubMed

    Kloos, H

    1996-01-01

    Ground-water contamination with the pesticides 1,2 dibromo-3-chloropropane (DBCP) and ethylene dibromide (EDB) affects Fresno/Clovis city in California. The spatial and temporal distribution of DBCP and EDB in public wells in Fresno/Clovis was examined, using mapping and time-series analyses of chemical test results, during the time periods 1979-1980 and 1992-1993. Health risks were estimated from mean concentrations, lifetime cancer risks were estimated, and monitoring and control programs were reviewed. Mean DBCP concentrations in selected wells declined from 0.56 ppb in 1979-1980 to 0.18 ppb in 1992-1993. Closure of wells and wellhead filtration caused levels to be reduced further (i.e., to 0.06 ppb). Mean EDB concentrations declined from 0.25 ppb to 0.15 ppb during the same time periods. The estimated lifetime cancer risk for DBCP was 1 excess death per 125 000 population in 1992-1993, but this risk varied within the city. The risk for EDB was 1 excess death per 2.2 million. Recommendations were made for the modeling of pesticide movement in ground water and for epidemiological studies.

  5. A comparison of the ability of a new bispyridinium oxime--1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium)butane dibromide and currently used oximes to reactivate nerve agent-inhibited rat brain acetylcholinesterase by in vitro methods.

    PubMed

    Kuca, K; Kassa, J

    2003-12-01

    The efficacy of a new bispyridinium oxime 1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium)butane dibromide, called K048, and currently used oximes (pralidoxime, obidoxime, the oxime HI-6) to reactivate acetylcholinesterase inhibited by various nerve agents (sarin, tabun, cyclosarin, VX) was tested by in vitro methods. The new oxime K048 was found to be a more efficacious reactivator of nerve agent-inhibited acetylcholinesterase than pralidoxime (in the case of VX, tabun and cyclosarin), obidoxime (cyclosarin and tabun) and HI-6 (tabun) but it did not reach the efficacy of currently used oximes for the reactivation of acetylcholinesterase inhibited by sarin. Thus, the oxime K048 seems to be a relatively efficacious broad spectrum acetylcholinesterase reactivator and, therefore, it could be useful for the treatment of a nerve agent-exposed population if information about detection of the type of nerve agent is not available.

  6. 75 FR 29435 - Diquat Dibromide; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ..., 1995.'' This statement was originally included as a footnote to import tolerances for banana and coffee... banana and coffee tolerances. The updated footnote to the table in paragraph (a)(3) reads ``There are no... cation in or on the following food commodites: Commodity Parts per million Banana\\1\\ 0.05 Coffee, bean...

  7. THE CRYSTAL STRUCTURE OF DIPHENYLTELLURIUM DIBROMIDE,

    DTIC Science & Technology

    TELLURIUM COMPOUNDS, *ORGANOMETALLIC COMPOUNDS, CRYSTAL STRUCTURE , CRYSTAL STRUCTURE , BROMIDES, SYMMETRY(CRYSTALLOGRAPHY), X RAY DIFFRACTION, FOURIER ANALYSIS, LEAST SQUARES METHOD, MOLECULAR STRUCTURE, CHEMICAL BONDS.

  8. One-electron oxidation in irradiated carbon tetrachloride solutions of ZnTPP, TMPD, and phenols. [Pulsed irradiation

    SciTech Connect

    Grodkowski, J.; Neta, P.

    1984-03-15

    One-electron oxidation of phenol, p-methoxphenol, N,N,N',N'-tetramethyl-p-phenylenediamine, chlorpromazine, and zinc tetraphenolporphyrin (ZnTPP) was studied by pulse radiolysis in carbon tetrachloride solutions. Phenols form phenoxyl radicals and the other compounds form cation radicals with yields strongly dependent on solute concentration. The highest yield in deoxygenated solutions approached G = 4. In the presence of oxygen an additional oxidation step is observed owing to CCl/sub 3/O/sub 2/ radicals and the overall oxidation yield approached G = 8. ZnTPP was found to be oxidized to the cation radical without any side effects, unlike oxidation in 1,2-dichloroethane which was accompanied by demetallation owing to HCl production.

  9. Ethylene Dibromide Mineralization in Soils under Aerobic Conditions

    PubMed Central

    Pignatello, Joseph J.

    1986-01-01

    1,2-Dibromoethane (EDB), which is a groundwater contaminant in areas where it was once used as a soil fumigant, was shown to be degraded aerobically by microorganisms in two types of surface soils from an EDB-contaminated groundwater discharge area. At initial concentrations of 6 to 8 μg/liter, EDB was degraded in a few days to near or below the detection limit of 0.02 μg/liter. At 15 to 18 mg/liter, degradation was slower. Bromide ion release at the higher concentrations was 1.4 ± 0.3 and 2.1 ± 0.2 molar equivalents for the two soils. Experiments with [14C]EDB showed that EDB was converted to approximately equal amounts of CO2 and apparent cellular carbon; only small amounts of added 14C were not attributable to these products or unreacted EDB. These results are encouraging, because they indicate that groundwater bacteria may hasten the removal of EDB from contaminated aerobic groundwater supplies. This report also provides evidence for soil-mediated chemical transformations of EDB. PMID:16347020

  10. New Antimony Lanthanide Disulfide Dibromides LnSbS

    SciTech Connect

    Gout, D.; Jobic, S.; Evain, M.; Brec, R.

    2001-05-01

    CeSbS{sub 2}Br{sub 2} (I), Ce{sub 1/2}La{sub 1/2}SbS{sub 2}Br{sub 2} (II), and LaSbS{sub 2}Br{sub 2} (III) have been synthesized at 700 C from a mixture of LnBr{sub 3}, Ln{sub 2}S{sub 3}, Sb, and S and characterized by single-crystal X-ray diffraction. The three phases are isostructural (space group P2{sub 1}/c, Z=4) and crystallize in a novel, dense, bidimensional structure with cell parameters a=8.709(3) {angstrom}, b=9.187(2) {angstrom}, c=17.397(5) {angstrom} {beta}=104.26(3) for I, a=8.739(7) {angstrom}, b=9.219(7) {angstrom}, c=17.41(2) {angstrom}, =104.3(1) for II, and a=8.785(1) {angstrom}, b=9.236(2) {angstrom}, c=17.372(3) {angstrom}, {beta}=104.09(2) for III. In these compounds, [Ln S{sub 5}Br{sub 4}] and [Ln S{sub 3}Br{sub 6}] (Ln=Ce, La) distorted tricapped trigonal prisms define infinite {sub {infinity}}{sup 2}[LnS{sub 2}Br{sub 2}] layers counterbalanced and capped by antimony cations. In good accordance with the structural features, the charge balance in these materials is to be written Ln{sup III}Sb{sup III}S{sup -II}{sub 2}Br{sup -I}{sub 2}. These compounds exhibit a yellow hue with a measured absorption threshold of 2.42(1), 2.55(1), and 2.72(1) eV for I, II, and III, respectively. In the two cerium containing bromothioantimonates I and II, the origin of the color is assigned to a Ce-4f{yields}Ce-5d electronic transition, which shifts to higher energy from I to II due either to a matrix effect (increase of the mean Ln-S distances under the substitution of Ce for La) or to an atomic ordering between Ce and La cations on the Ln(1) and Ln(2) crystallographic sites. In contrast, the electronic transition at play in III involves a charge transfer from the bromine and sulfur ions to the antimony ions, the latter contributing substantially to the lowermost levels of the conduction band.

  11. Ionothermal synthesis, crystal structure and solid-state NMR spectroscopy of a new organically templated gallium oxalatophosphate: (H2TMPD)0.5[Ga3(C2O4)0.5(PO4)3] (TMPD=N,N,N',N'-tetramethyl-1,3-propanediamine).

    PubMed

    Tang, Ming-Feng; Liu, Yi-Hui; Chang, Pai-Ching; Liao, Yi-Chen; Kao, Hsien-Ming; Lii, Kwang-Hwa

    2007-10-28

    A new organically templated gallium oxalatophosphate, (C7H20N2)0.5[Ga3(C2O4)0.5(PO4)3], has been synthesized by using a low-melting-point eutectic mixture of choline chloride and oxalic acid as a solvent and characterized by single-crystal X-ray diffraction, thermogravimetric analysis and solid-state NMR spectroscopy. It is the first example of ionothermal synthesis of organically templated metal oxalatophosphate. The structure contains double 6-ring units of the composition Ga6(PO4)6 which are connected by oxalate ligands and P-O-Ga bonds to form a 3-D framework. The charge-compensating organic ammonium cations which are disordered over two positions are located at the intersections of two types of 8-ring channels. 1H MAS and 13C CPMAS NMR studies confirm the presence of N,N,N',N'-tetramethyl-1,3-propanediammonium cation. The 71Ga and 31P MAS NMR spectra are also consistent with the crystal structure analysis results.

  12. Field-observed ethylene dibromide in an aquifer after two decades

    NASA Astrophysics Data System (ADS)

    Pignatello, Joseph J.; Frink, Charles R.; Marin, Paul A.; Droste, Edward X.

    1990-01-01

    The fate and transport of the soil fumigant, 1,2-dibromoethane (EDB) was studied at a former tobacco field in Simsbury, Connecticut where it was last used in 1967. The subsurface consists of glacial deposits of stratified sand, gravel, and silt underlain by a fractured sandstone/siltstone bedrock. Contaminant plumes in the bedrock had migrated only slightly from beneath the tobacco field after nearly two decades, consistent with calculated flow velocities. Contaminant levels in the overburden aquifer were much lower, which was consistent with higher calculated flow velocities resulting in off-site discharge to a nearby stream, and possibly with faster biodegradation. EDB concentrations in both zones were stable over the study period (1.5-2yr). Earlier demonstration of relatively fast biodegradation of 14C-EDB in aquifer core samples were contradicted by the plume stabilities observed here. EDB was found in vadose cores, particularly topsoils, at concentrations up to 32μg kg -1. These residues could not be extracted with water, even after 20 d, and were unavailable for biodegradation. By contrast added 14C-EDBwas mineralized almost completely in 22 d. EDB was also found in overburden aquifer cores, in some cases at concentrations much greater than predicted from equilibrium partition experiments. The results show that kinetically slow, nonequilibrium sorption is a factor in the decades-long persistence of this chemical in the topsoil and possibly in the aquifer.

  13. 75 FR 74714 - DCNA (dicloran), Ziram, Diquat Dibromide, and Chloropicrin; Notice of Receipt of Requests to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-01

    ... terminate or delete uses. The requests would delete DCNA use on potatoes, ziram use on blackberries, diquat..... DCNA Potato. 10163-226 Botran 5F Fungicide.... DCNA Potato. 10163-195 Botran Technical....... DCNA Potato. 45728-12 Ziram Granuflo Ziram Blackberries. Fungicide. 58266-2 TRI-CLOR FUMIGANT...

  14. 75 FR 17712 - Malathion and Diquat Dibromide; Cancellation Order for Amendments to Terminate Uses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-07

    ... certain uses of these product registrations. These are not the last products containing these pesticides... INFORMATION CONTACT: Eric Miederhoff, Pesticide Re- evaluation Division, Office of Pesticide Programs... agricultural advocates; the chemical industry; pesticide users; and members of the public interested in the...

  15. Biological and Abiotic Transformations of Ethylene Dibromide and 1,2-Dichloroethane in Ground Water at Leaded Gasoline Spill Sites

    EPA Science Inventory

    Tetra-ethyl lead was widely used in leaded automobile gasoline from 1923 until 1987. To prevent lead deposits from fouling the engine, 1,2-dibromoethane (EDB) and 1,2-dichloroethane (1,2-DCA) were added to the gasoline to act as lead scavengers. The Maximum Contaminant Levels...

  16. Biodegradation of ethylene dibromide (1,2-dibromoethane [EDB]) in microcosms simulating in situ and biostimulated conditions.

    PubMed

    McKeever, Robert; Sheppard, Diane; Nüsslein, Klaus; Baek, Kyung-Hwa; Rieber, Khalil; Ergas, Sarina J; Forbes, Rose; Hilyard, Mark; Park, Chul

    2012-03-30

    Although 1,2-dibromoethane (EDB) is a common groundwater contaminant, there is the lack of knowledge surrounding EDB biodegradation, especially under aerobic conditions. We have performed an extensive microcosm study to investigate the biodegradation of EDB under simulated in situ and biostimulated conditions. The materials for soil microcosms were collected from an EDB-contaminated aquifer at the Massachusetts Military Reservation in Cape Cod, MA. This EDB plume has persisted for nearly 40 years in both aerobic and anaerobic EDB zones of the aquifer. Microcosms were constructed under environmentally relevant conditions (field EDB and DO concentrations; incubated at 12°C). The results showed that natural attenuation occurred under anaerobic conditions but not under aerobic conditions, explaining why aerobic EDB contamination is so persistent. EDB degradation rates were greater under biostimulated conditions for both the aerobic and anaerobic microcosms. Particularly for aerobic biostimulation, methane-amended microcosms degraded EDB, on average, at a first order rate eight times faster than unamended microcosms. The best performing replicate achieved an EDB degradation rate of 7.0 yr(-1) (half-life (t(1/2))=0.10 yr). Residual methane concentrations and the emergence of methanotrophic bacteria, measured by culture independent bacterial analysis, provided strong indications that EDB degradation in aerobic methane-amended microcosms occurred via cometabolic degradation. These results indicate the potential for enhanced natural attenuation of EDB and that methane could be considered co-substrate for EDB bioremediation for the EDB-contaminated groundwater in aerobic zone. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. 3,3'-Di-n-propyl-1,1'-[p-phenyl-enebis(methyl-ene)]diimidazolium dibromide.

    PubMed

    Haque, Rosenani A; Nasri, S Fatimah; Hemamalini, Madhukar; Fun, Hoong-Kun

    2011-08-01

    The asymmetric unit of the title compound, C(20)H(28)N(4) (2+)·2Br(-), consists of half a 3,3'-di-n-propyl-1,1'-[p-phenyl-enenis(methyl-ene)]diimidazolium cation and a bromide anion. The cation is located on an inversion center and adopts an ⋯AAA⋯ trans conformation. In the crystal, the cation is linked to the anions via weak C-H⋯Br hydrogen bonds.

  18. Biological and Abiotic Transformations of Ethylene Dibromide and 1,2-Dichloroethane in Ground Water at Leaded Gasoline Spill Sites

    EPA Science Inventory

    Tetra-ethyl lead was widely used in leaded automobile gasoline from 1923 until 1987. To prevent lead deposits from fouling the engine, 1,2-dibromoethane (EDB) and 1,2-dichloroethane (1,2-DCA) were added to the gasoline to act as lead scavengers. The Maximum Contaminant Levels...

  19. An acridine derivative, [4,5-bis{(N-carboxy methyl imidazolium)methyl}acridine] dibromide, shows anti-TDP-43 aggregation effect in ALS disease models

    PubMed Central

    Prasad, Archana; Raju, Gembali; Sivalingam, Vishwanath; Girdhar, Amandeep; Verma, Meenakshi; Vats, Abhishek; Taneja, Vibha; Prabusankar, Ganesan; Patel, Basant K.

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease associated with aggregation of TAR DNA-binding protein-43 (TDP-43) in neuronal cells and manifests as motor neuron dysfunction & muscle atrophy. The carboxyl-terminal prion-like domain of TDP-43 can aggregate in vitro into toxic β-sheet rich amyloid-like structures. So far, treatment options for ALS are very limited and Riluzole, which targets glutamate receptors, is the only but highly ineffective drug. Therefore, great interest exists in developing molecules for ALS treatment. Here, we have examined certain derivatives of acridine containing same side chains at position 4 & 5, for inhibitory potential against TDP-43 aggregation. Among several acridine derivatives examined, AIM4, which contains polar carboxyl groups in the side arms, significantly reduces TDP-43-YFP aggregation in the powerful yeast model cell and also abolishes in vitro amyloid-like aggregation of carboxyl terminal domain of TDP-43, as observed by AFM imaging. Thus, AIM4 can be a lead molecule potentiating further therapeutic research for ALS. PMID:28000730

  20. Optical characteristics and parameters of the plasma of a barrier discharge excited in a mixture of mercury dibromide vapor with nitrogen and helium

    NASA Astrophysics Data System (ADS)

    Malinina, A. A.; Guivan, N. N.; Shimon, L. L.; Shuaibov, A. K.

    2010-09-01

    Results are presented from experimental and theoretical studies of the optical characteristics and parameters of the plasma of an atmospheric-pressure barrier discharge excited in a HgBr2: N2: He mixture, which was used as the working medium of a small-size (with a radiation area of 8 cm2) exciplex gas-discharge radiation source. The mean radiation power of 87 mW was achieved at the radiation wavelength λmax = 502 nm. The electron energy distribution function, the transport characteristics, the specific energy lost in the processes involving electrons, the electron temperature and density, and the rate constants of elastic and inelastic electron scattering by the components of the working mixture were calculated as functions of the reduced field E/ N. The plasma of a discharge excited in a HgBr2: N2: He mixture can be used as the working medium of a small-size blue-green radiation source. Such a source can find application in biotechnology, photonics, and medicine and can also be used to manufacture gas-discharge display panels.

  1. Effect of Diquat (1,1′-Ethylene-2,2′-Dipyridylium Dibromide) on the Photosynthetic Growth of Rhodospirillum rubrum

    PubMed Central

    Kaneshiro, Tsuneo; Zweig, Gunter

    1965-01-01

    Diquat (2 × 10-4m) inhibited both aerobic and anaerobic growth of Rhodospirillum rubrum. With photosynthetic cultures, diquat affected the synthesis of bacteriochlorophyll more readily than cell mass (turbidity). Diquat retarded the synthesis of bacteriochlorophyll and some protein more readily than that of other cellular constituents such as ribonucleic acid, deoxyribonucleic acid, and cell mass. With cells deficient in phosphate, diquat inhibited the uptake-conversion of inorganic phosphate completely only when 3-(3,4-dichlorophenyl)-1,1′-dimethyl urea and ascorbate were also present. PMID:5866040

  2. Use of a quantitative oxidase test for characterizing oxidative metabolism in bacteria.

    PubMed Central

    Jurtshuk, P; McQuitty, D N

    1976-01-01

    It was possible to quantitate the terminal oxidase(s) reaction using bacterial resting-cell suspensions and demonstrate the usefulness of this reaction for taxonomic purposes. Resting-cell suspensions of physiologically diverse bacteria were examined for their capabilities of oxidizing N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) using a manometric assay. For organisms having this capability, it was possible to calculate the conventional TMPD oxidase Q(O2) value (microliters of O2 consumed per hour per milligram [dry weight]). All cultures were grown heterotrophically at 30 C, under identical nutritional conditions, and were harvested at the late-logarithmic growth phase. The TMPD oxidase Q(O2) values showed perfect correlation with the Kovacs oxidase test and, in addition, it was possible to define quantitatively that point which separated oxidase-positive from oxidase-negative bacteria. Oxidase-negative bacteria exhibited a TMPD oxidase Q(O2) value (after correcting for the endogenous by substraction) of less than or equal 33 and had an uncorrected TMPD/endogenous ratio of less than or equal 5. The TMPD oxidase Q(O2) values were also correlated with the data obtained for the Hugh-Leifson Oxferm test. In general, bacteria that exhibited a respiratory mechanism had high TMPD oxidase values, whereas fermentative organsims had low TMPD oxidase activity. All exceptions to this are noted. This quantitative study also demonstrated that organisms that (i) lack a type c cytochrome, or (ii) lack a cytochrome-containing electron transport system, like the lactic acid bacteria, exhibited low or negligible TMPD oxidase Q(O2) values. From the 79 bacterial species (36 genera) examined, it appears that this quantitative oxidase test has taxonomic value that can differentiate the oxidative relationships between bacteria at the subspecies, species, and genera levels. PMID:1275489

  3. Crystal structure of (±)-[trans-cyclo­hexane-1,2-diylbis(aza­nedi­yl)]di­phospho­nium dibromide dichloro­methane disolvate

    PubMed Central

    Rodríguez Álvarez, Aurora; Tlahuext, Hugo; Grévy, Jean-Michel

    2016-01-01

    The cation of the title solvated salt, C42H42N2P2 2+·2Br−·2CH2Cl2, lies on a crystallographic twofold rotation axis. The 1,2-di­amino­cyclo­hexane fragment has a chair conformation with two N atoms in a transoid conformation [N—C—C—N = 163.4 (2)°]. In the crystal, the cations are linked to the anions by N—H⋯Br and C—H⋯Br hydrogen bonds, forming a chain structure along the c axis. The di­chloro­methane mol­ecule takes part in the hydrogen-bond network through C—H⋯π and C—H⋯Br inter­actions. PMID:27375889

  4. Effect of spacer length on the interfacial behavior of N,N'-bis(dimethylalkyl)-α,ω-alkanediammonium dibromide gemini surfactants in the absence and presence of ZnO nanoparticles.

    PubMed

    Fereidooni Moghadam, Tahereh; Azizian, Saeid; Wettig, Shawn

    2017-01-15

    In this paper the interfacial behavior of aqueous solutions of cationic gemini surfactants of the, N,N'-bis(dimethylalkyl)-α,ω-alkanediammoniumdibromide type (known as the 12-s-12 series), in the absence and presence of ZnO nanoparticles was studied. Equilibrium and dynamic interfacial tension between n-decane and aqueous surfactant solutions were investigated. It was concluded that the synergistic effect between surfactants and nanoparticles increases the surfactant efficiency with respect to reducing the interfacial tension. Moreover, the magnitude of the effect of ZnO nanoparticles on the interfacial tension decreases with increasing length of the spacer group in the gemini surfactant structure. Dynamic studies illustrate that the migration mechanism of gemini surfactants (regardless of the presence of ZnO) from the bulk to the interface was controlled by both diffusion and adsorption. The effect of spacer length on the contact angle and emulsion stability both with and without nanoparticles was also studied. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Assessment of ethylene dibromide, dibromochloropropane, other volatile organic compounds, radium isotopes, radon, and inorganic compounds in groundwater and spring water from the Crouch Branch and McQueen Branch aquifers near McBee, South Carolina, 2010-2012

    USGS Publications Warehouse

    Landmeyer, James E.; Campbell, Bruce G.

    2014-01-01

    The water-quality data collected between 2010 and 2012, in conjunction with groundwater flow pathways and historical aerial photographs of land uses near McBee, indicate an area where EDB-, DBCP-, 1,2-dichloropropane-, 1,3-dichloropropane-, and carbon disulfide-contaminated groundwater exists in the Crouch Branch aquifer in the Cedar Creek Basin and north of McBee and is most likely related to the past use of these compounds between the early 1900s and the 1980s as soil fumigants in predominately agricultural areas north of McBee. The highest EDB concentration detected (18.6 micrograms per liter) during the 3-year study was in a groundwater sample from an agricultural-supply well located north of McBee. Other VOCs, such as dichloromethane and 1,1,2-trichloroethane, also were detected in groundwater samples from this EDB-contaminated agricultural-supply well but are from unknown source(s). The fact that the agricultural area north of McBee is located in a recharge area for the Crouch Branch aquifer most likely facilitated the groundwater contamination in this area. DBCP-contaminated groundwater detected in three public-supply wells south of McBee in the deeper McQueen Branch aquifer appears to be related to past soil fumigation practices that used DBCP in agricultural areas located south of McBee. One of the three DBCP-contaminated public-supply wells also contained EDB, most likely present in groundwater due to the release of leaded gasolines that contained EDB as a fuel additive between the 1940s and 1970s. A gasoline-source of EDB, rather than a soil-fumigation source, is supported by the co-detection in groundwater from the well of 1,2-dichloroethane, a lead scavenger compound also added to leaded gasoline. Groundwater pumped from two public-supply wells located within and to the east of the McBee town limits and one domestic-supply well east of McBee was characterized by the detection of 1,1-dichloroethane, trichloroethylene, 1,1-dichloroethylene, and perchloroethylene. Groundwater flow pathways determined for these wells indicate that the potential source(s) of these compounds detected in one public-supply well and the domestic-supply well may be located within the McBee town limits, and that the potential source(s) of these compounds detected in the public-supply well to the east of McBee may be located in an area north of McBee formerly used for agriculture, but used for industry since at least the 1970s. Radium isotopes (defined in this study as the sum of radium-226 and radium-228 concentrations) and radon were detected in all wells sampled in the McBee area between 2010 and 2012. Wells characterized by radium isotope concentrations in groundwater that exceeded the MCL of 5.0 picocuries per liter were also characterized by specific conductance values greater than 30 microsiemens per centimeter and clustered north of McBee in a predominately agricultural area, and in agricultural and urban areas located within and east of McBee. The elevated specific conductance values measured in groundwater from these wells most likely are due to recharge by water mineralized by fertilizer application in agricultural areas, or due to the recharge by water mineralized by septic-tank drain-field effluent near urban areas. Radon was detected in groundwater from all wells sampled, and radon concentrations in groundwater from three monitoring wells exceeded the proposed MCL of 300 picocuries per liter. Concentrations of uranium in groundwater in the McBee area increased with increased groundwater-sample depth, most likely due to the proximity of the sample-collection location to basement rock that contains uranium-bearing minerals.

  6. Crystal structure of N-[3-(di-methyl-aza-nium-yl)prop-yl]-N',N',N'',N''-tetra-methyl-N-(N,N,N',N'-tetra-methyl-form-am-id-in-ium-yl)-guanidinium dibromide hydroxide monohydrate.

    PubMed

    Tiritiris, Ioannis; Kantlehner, Willi

    2015-12-01

    The asymmetric unit of the title hydrated salt, C15H37N6 (3+)·2Br(-)·OH(-)·H2O, contains one cation, three partial-occupancy bromide ions, one hydroxide ion and one water mol-ecule. Refinement of the site-occupancy factors of the three disordered bromide ions converges with occupancies 0.701 (2), 0.831 (2) and 0.456 (2) summing to approximately two bromide ions per formula unit. The structure was refined as a two-component inversion twin with volume fractions 0.109 (8):0.891 (8) for the two domains. The central C3N unit of the bis-amidinium ion is linked to the aliphatic propyl chain by a C-N single bond. The other two bonds in this unit have double-bond character as have the four C-N bonds to the outer NMe2 groups. In contrast, the three C-N bonds to the central N atom of the (di-methyl-aza-nium-yl)propyl group have single-bond character. Delocalization of the two positive charges occurs in the N/C/N and C/N/C planes, while the third positive charge is localized on the di-methyl-ammonium group. The crystal structure is stabilized by O-H⋯O, N-H⋯Br, O-H⋯Br and C-H⋯Br hydrogen bonds, forming a three-dimensional network.

  7. Ciprofloxacin photosensitized oxidation of 2'-deoxyguanosine-5'-monophosphate in neutral aqueous solution.

    PubMed

    Liu, Yancheng; Zhang, Peng; Li, Haixia; Wang, Wenfeng

    2012-01-01

    Laser flash photolysis studies have been carried out to investigate the reactions of ciprofloxacin (CPX) with 2'-deoxyguanosine-5'-monophosphate (dGMP), N, N, N', N'-tetramethyl-p-phenylenediamine (TMPD) and ferulic acid (FCA) in neutral aqueous solutions, respectively. CPX triplet state ((3)CPX*) can be quenched by TMPD, FCA and dGMP, with rate constants of 1.8 × 10(9), 1.5 × 10(9) and 5.8 × 10(7) dm(3) mol(-1) s(-1), respectively. TMPD radical cation (TMPD(·+)) and FCA radical cation (FCA(·+)) were observed directly. The formation rate of CPX radical anion (CPX(·-)) was determined to be 1.5 × 10(9) dm(3) mol(-1) s(-1). Redox reaction of dGMP was investigated through competing reactions using TMPD and FCA as probe. The triplet energy of CPX was determined to be 262 kJ mol(-1). Electron transfer from TMPD, FCA and dGMP to (3)CPX* was proposed. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  8. Kinetic and ligand binding evidence for two heme A-based terminal oxidases in plasma membranes from Bacillus subtilis.

    PubMed

    Hill, B C; Vo, L; Albanese, J

    1993-02-15

    Detergent-solubilized plasma membranes from Bacillus subtilis have been characterized for their cytochrome oxidase content. Triton X-100-solubilized membranes show high O2 turnover with ascorbate plus TMPD. Reduced-oxidized difference spectroscopy of ascorbate-TMPD-reduced membranes reveals the presence of cytochrome c and cytochrome a. An additional, b-type cytochrome appears when the membranes are reduced with dithionite. Time-resolved difference spectra taken during reduction by ascorbate-TMPD reveal two kinetic forms of heme A-containing cytochromes. There is a high-turnover form that is rapidly reduced upon anaerobiosis, and a second type which is only slowly reduced upon anaerobiosis. The slowly reduced oxidase is distinguished by an alpha-band blue-shifted to 600 nm relative to the 603-nm position observed for high-turnover oxidase. Addition of CO to ascorbate-TMPD-reduced membranes gives a spectrum typical of ferrocytochrome a3-CO, and the intensity corresponds to the total ferrocytochrome a3 concentration. Photolysis of ascorbate-TMPD-reduced, CO-bound membranes indicates that both species are photosensitive with similar rates of recombination. Addition of CO to dithionite-reduced membranes shows an additional CO reactive center that has a spectrum characteristic of cytochrome o. Cyanide blocks complete reduction of high-turnover oxidase by ascorbate plus TMPD, but does not appear to effect slowly reduced oxidase. These results indicate the presence of two different types of cytochrome aa3 oxidase in plasma membranes of B. subtilis.

  9. 27 CFR 21.56 - Formula No. 29.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... intermediates. 551.Acetaldehyde. 552.Other aldehydes. 561.Ethyl ether. 562.Other ethers. 571.Ethylene dibromide. 572.Ethylene gas. 573.Xanthates. 575.Drugs and medicinal chemicals. 579.Other chemicals....

  10. 78 FR 59019 - Product Cancellation Order for Certain Pesticide Registrations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ... Pendimethalin. Herbicide. 000241-00403 Pendimethalin Pendimethalin. Manufacturing Concentrate Herbicide. 000264-00807 Calypso 70WG Thiacloprid. Insecticide. 009688-00198 Chemsico Herbicide Prometon, Diquat Concentrate DP. dibromide. 009688-00218 Chemsico Herbicide Prometon, Diquat RTU DP. dibromide. 053883-00135...

  11. Reduction of Hg2+ with reduced mammalian cytochrome c by cytochrome c oxidase purified from a mercury-resistant acidithiobacillus ferrooxidans strain, MON-1.

    PubMed

    Sugio, Tsuyoshi; Fujii, Mitsuko; Ninomiya, Yumika; Kanao, Tadayoshi; Negishi, Atsunori; Takeuchi, Fumiaki

    2008-07-01

    Acidithiobacillus ferrooxidans AP19-3, ATCC 23270, and MON-1 are mercury-sensitive, moderately mercury-resistant, and highly mercury-resistant strains respectively. It is known that 2,3,5,6-tetramethyl-p-phenylendiamine (TMPD) and reduced cytochrome c are used as electron donors specific for cytochrome c oxidase. Resting cells of strain MON-1 had TMPD oxidase activity and volatilized metal mercury with TMPD as an electron donor. Cytochrome c oxidase purified from strain MON-1 reduced mercuric ions to metalic mercury with reduced mammalian cytochrome c as well as TMPD. These mercury volatilization activities with reduced cytochrome c and TMPD were completely inhibited by 1 mM NaCN. These results indicate that cytochrome c oxidase is involved in mercury reduction in A. ferrooxidans cells. The cytochrome c oxidase activities of strains AP19-3 and ATCC 23270 were completely inhibited by 1 muM and 5 muM of mercuric chloride respectively. In contrast, the activity of strain MON-1 was inhibited 33% by 5 muM, and 70% by 10 muM of mercuric chloride, suggesting that the levels of mercury resistance in A. ferrooxidans strains correspond well with the levels of mercury resistance of cytochrome c oxidase.

  12. Induction of autoimmunity by pristane and other naturally-occurring hydrocarbons

    PubMed Central

    Reeves, Westley H.; Lee, Pui Y.; Weinstein, Jason S.; Satoh, Minoru; Lu, Li

    2009-01-01

    Tetramethylpentadecane (TMPD, or commonly known as pristane)-induced lupus is a murine model of systemic lupus erythematosus (SLE). Renal disease and autoantibody production strictly depend on signaling through the interferon (IFN)-I receptor. The major source of IFN-I is immature monocytes bearing high levels of the surface marker Ly6C. Interferon production is mediated exclusively by signaling through TLR7 and the adapter protein MyD88. It is likely that endogenous TLR7 ligands such as components of small nuclear ribonucleoprotein complexes are involved in triggering disease. Lupus autoantibodies are produced in ectopic lymphoid tissue developing in response to TMPD. This model is well suited for examining links between dysregulated IFN-I production and the pathogenesis of human SLE, which like TMPD-lupus, is associated with high levels of IFN-I. PMID:19699150

  13. Crystal structure of N-[3-(di­methyl­aza­nium­yl)prop­yl]-N′,N′,N′′,N′′-tetra­methyl-N-(N,N,N′,N′-tetra­methyl­form­am­id­in­ium­yl)­guanidinium dibromide hydroxide monohydrate

    PubMed Central

    Tiritiris, Ioannis; Kantlehner, Willi

    2015-01-01

    The asymmetric unit of the title hydrated salt, C15H37N6 3+·2Br−·OH−·H2O, contains one cation, three partial-occupancy bromide ions, one hydroxide ion and one water mol­ecule. Refinement of the site-occupancy factors of the three disordered bromide ions converges with occupancies 0.701 (2), 0.831 (2) and 0.456 (2) summing to approximately two bromide ions per formula unit. The structure was refined as a two-component inversion twin with volume fractions 0.109 (8):0.891 (8) for the two domains. The central C3N unit of the bis­amidinium ion is linked to the aliphatic propyl chain by a C—N single bond. The other two bonds in this unit have double-bond character as have the four C—N bonds to the outer NMe2 groups. In contrast, the three C—N bonds to the central N atom of the (di­methyl­aza­nium­yl)propyl group have single-bond character. Delocalization of the two positive charges occurs in the N/C/N and C/N/C planes, while the third positive charge is localized on the di­methyl­ammonium group. The crystal structure is stabilized by O—H⋯O, N—H⋯Br, O—H⋯Br and C—H⋯Br hydrogen bonds, forming a three-dimensional network. PMID:26870507

  14. Bis(2,2'-bipyridine)[1,9-bis(diphenylphos-phanyl)-1,2,3,4,6,7,8,9-octahydropyrim-ido[1,2-a]pyrimidin-5-ium]ruthenium(II) hexa-fluorido-phosphate dibromide di-chloro-methane disolvate monohydrate.

    PubMed

    Shang, Congcong; Vendier, Laure; Sutra, Pierre; Igau, Alain

    2013-11-06

    In the cation of the title complex, [Ru(C31H32N3P2)(C10H8N2)2](PF6)(Br)2·2CH2Cl2·H2O, the ruthenium ion is coordinated in a distorted octa-hedral geometry by two 2,2'-bi-pyridine (bpy) ligands and a chelating cationic N-di-phenyl-phosphino-1,3,4,6,7,8-hexa-hydro-2-pyrimido[1,2-a]pyrimidine [(PPh2)2-hpp] ligand. The tricationic charge of the complex is balanced by two bromide and one hexa-fluorido-phosphate counter-anions. The compound crystallized with two mol-ecules of di-chloro-methane (one of which is equally disordered about a Cl atom) and a water mol-ecule. In the crystal, one of the Br anions bridges two water mol-ecules via O-H⋯Br hydrogen bonds, forming a centrosymmetric diamond-shaped R (4) 2(8) motif. The cation and anions and the solvent mol-ecules are linked via C-H⋯F, C-H⋯Br, C-H⋯Cl and C-H⋯O hydrogen bonds, forming a three-dimensional network.

  15. Kinetics of manganese(III) acetate in acetic acid: Generation of Mn(III) with Co(III), Ce(IV), and dibromide radicals; reactions of Mn(III) with Mn(II), Co(II), hydrogen bromide, and alkali bromides

    SciTech Connect

    Jiao, X.D.; Espenson, J.H.

    2000-04-03

    The reaction of cobalt(III) acetate with excess manganese(II) acetate in acetic acid occurs in two stages, since the two forms Co(IIIc) and Co(IIIs) are not rapidly equilibrated and thus react independently. The rate constants at 24.5 C are {kappa}{sub c} = 37.1 {+-} 0.6 L mol{sup {minus}1} s{sup {minus}1} and {kappa}{sub s} = 6.8 {+-} 0.2 L mol{sup {minus}1} s{sup {minus}1} at 24.5 C in glacial acetic acid. The Mn(III) produced forms a dinuclear complex with the excess of Mn(II). This was studied independently and is characterized by the rate constant (3.43 {+-} 0.01) x 10{sup 2} L mol{sup {minus}1} s{sup {minus}1} at 24.5 C. A similar interaction between Mn(III) and Co(II) is substantially slower, with {kappa} = (3.73 {+-} 0.05) x 10{sup {minus}1} L mol{sup {minus}1} s{sup {minus}1} at 24.5 C. Mn(II) is also oxidized by Ce(IV), according to the rate law {minus}d[Ce(IV)]/dt = {kappa}[Mn(II)]{sup 2}[Ce(IV)], where {kappa} = (6.0 {+-} 0.2) x 10{sup 4} L{sup 2} mol{sup {minus}2} s{sup {minus}1}. The reaction between Mn(II) and HBr{sub 2}{sup {sm_bullet}}, believed to be involved in the mechanism by which Mn(III) oxidizes HBr, was studied by laser photolysis; the rate constant is (1.48 {+-} 0.04) x 10{sup 8} L mol{sup {minus}1} s{sup {minus}1} at {approximately}23 C in HOAc. Oxidation of Co(II) by HBr{sub 2}{sup {sm_bullet}} has the rate constant (3.0 {+-} 0.1) x 10{sup 7} L mol{sup {minus}1} s{sup {minus}1}. The oxidation of HBr by Mn(III) is second order with respect to [HBr]; {kappa} = (4.10 {+-} 0.08) x 10{sup 5} L{sup 2} mol{sup {minus}2} s{sup {minus}1} at 4.5 C in 10% aqueous HOAc. Similar reactions with alkali metal bromides were studied; their rate constants are 17--23 times smaller. This noncomplementary reaction is believed to follow that rate law so that HBr{sub 2}{sup {sm_bullet}} and not Br{sup {sm_bullet}} (higher in Gibbs energy by 0.3 V) can serve as the intermediate. The analysis of the reaction steps then requires that the oxidation of HBr{sub 2}{sup {sm_bullet}} to Br{sub 2} by Mn(III) be diffusion controlled, which is consistent with the driving force and seemingly minor reorganization.

  16. 40 CFR Table 36 to Subpart G of... - Compound Lists Used for Compliance Demonstrations for Enhanced Biological Treatment Processes...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Ethylene Glycol MonobutylEther Acetate Chloroprene. Ethylene Glycol MonomethylEther Acetate Cumene (isopropylbenzene). Ethylene Glycol Dimethyl Ether Dibromoethane 1,2. Hexachlorobenzene Dichlorobenzene 1,4.... Ethylbenzene. Ethylene Oxide. Ethylene Dibromide. Hexachlorobutadiene. Hexachloroethane. Hexane-n....

  17. 40 CFR Table 36 to Subpart G of... - Compound Lists Used for Compliance Demonstrations for Enhanced Biological Treatment Processes...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Ethylene Glycol MonobutylEther Acetate Chloroprene. Ethylene Glycol MonomethylEther Acetate Cumene (isopropylbenzene). Ethylene Glycol Dimethyl Ether Dibromoethane 1,2. Hexachlorobenzene Dichlorobenzene 1,4.... Ethylbenzene. Ethylene Oxide. Ethylene Dibromide. Hexachlorobutadiene. Hexachloroethane. Hexane-n....

  18. 40 CFR Table 36 to Subpart G of... - Compound Lists Used for Compliance Demonstrations for Enhanced Biological Treatment Processes...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Ethylene Glycol MonobutylEther Acetate Chloroprene. Ethylene Glycol MonomethylEther Acetate Cumene (isopropylbenzene). Ethylene Glycol Dimethyl Ether Dibromoethane 1,2. Hexachlorobenzene Dichlorobenzene 1,4.... Ethylbenzene. Ethylene Oxide. Ethylene Dibromide. Hexachlorobutadiene. Hexachloroethane. Hexane-n. Methyl...

  19. 40 CFR 142.62 - Variances and exemptions from the maximum contaminant levels for organic and inorganic chemicals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Dibromochloropropane X X (27) 2,4-D X (28) Ethylene dibromide X X (29) Heptachlor X (30) Heptachlor epoxide X (31... for the inorganic chemicals listed in § 141.62: BAT for Inorganic Compounds Listed in §...

  20. Optical and electrochemical properties of ordered macroporous gold array on the ITO surface

    NASA Astrophysics Data System (ADS)

    Lu, Huidan; Liu, Yongping; Han, Guo-Cheng

    2011-06-01

    The electrochemical and optical properties of transparent, two-dimensional macroporous gold film were investigated. Colloidal crystal templates were assembled onto indium-doped tin oxide (ITO) glass surface through vertical depositing method. Following gold electrodeposition, they were removed by dissolution with tetrahydrofuran (THF). The highly ordered macroporous gold array was achieved. It was characterized by scanning electron microscope (SEM) and ultraviolet visible (UV-vis) spectrophotometry. The optical transparency of the gold film was near 25% and fairly constant between 300 and 900 nm. The macroporous gold film electrode was mounted into a thin-layer transmission cell. The electrochemical response was evaluated by thin-layer cyclic voltammograms (CV) of the Fe (CN) 63-/Fe (CN) 64- couple. Thin-layer cell exhibits good shape of waves and nearly symmetric cathodic and anodic waves. E0' value and n of TMPD + rad /TMPD (TMPD is acronyms for N,N,N',N'-tetramethyl-p-phenylenediamine, and TMPD + rad is its mono-cation radical) couple were determined. Furthermore, results demonstrated electrolytic equilibrium was faster reached in macroporous gold film than ITO electrode.

  1. Laser diagnostics of an evaporating electrospray

    NASA Astrophysics Data System (ADS)

    Yi, Tongxun

    2014-01-01

    An electrospray atomizer generates monodisperse, dilute sprays when working in the cone-jet mode. Evolution of an electrospray with droplet diameter below 10 μm is studied with phase Doppler particle analyzer (PDPA) and the exciplex-PLIF technique. The evaporation rate constant is determined from droplet velocity and diameter measured with a PDPA and is found to sharply increase with the velocity slip and the coflow temperature. Fluorescence around 400 nm, usually referred to as TMPD fluorescence, is calibrated with a heated, laminar, coflow vapor jet diluted with nitrogen. The TMPD fluorescence yield nonlinearly increases with temperature up to 538 K and then declines. Single-shot images show that fluorescence around 400 nm is mainly generated from TMPD vapor and that from droplets can be neglected as a first analysis; however, fluorescence around 490 nm, usually referred to as exciplex fluorescence, is generated from both droplets and fuel vapor immediately around droplets. Exciplex fluorescence is correlated with PDPA measurements and TMPD fluorescence. Effects of temperature, fuel composition, overlap of fluorescent spectra, and chemical equilibrium for exciplex formation are discussed. Technical challenges for quantitative exciplex-PLIF measurements are highlighted.

  2. Isolation and purification of the cytochrome oxidase of Azotobacter vinelandii.

    PubMed

    Jurtshuk, P; Mueller, T J; Wong, T Y

    1981-09-14

    A membrane-bound cytochrome oxidase for Azobacter vinelandii was purified 20-fold using a detergent-solubilization procedure. Activity was monitored using as ascorbate-TMPD oxidation assay. The oxidase was 'solubilized' from a sonic-type electron-transport particle (R3 fraction) using Triton X-100 and deoxycholate. Low detergent concentrations first solubilized the flavoprotein oxidoreductases, then higher concentrations of Triton X-100 and KCl solubilized the oxidase, which was precipitated at 27-70% (NH4)2SO4. The highly purified cytochrome oxidase has a V of 60-78 microgatom O consumed/min per mg protein. TMPD oxidation by the purified enzyme was inhibited by CO, KCN, NaN3 and NH2OH; NaNO2 (but not NaNO3) also had a potent inhibitory effect. Spectral analyses revealed two major hemoproteins, the c-type cytochrome c4 and cytochrome o; cytochromes a1 and d were not detected. The Azotobacter cytochrome oxidase is an integrated cytochrome c4-o complex, TMPD-dependent cytochrome oxidase activity being highest in preparations having a high c-type cytochrome content. This TMPD-dependent cytochrome oxidase serves as a major oxygen-activation site for the A. vinelandii respiratory chain. It appears functionally analogous to cytochrome a+a3 oxidase of mammalian mitochondria.

  3. Indoor molds, bacteria, microbial volatile organic compounds and plasticizers in schools--associations with asthma and respiratory symptoms in pupils.

    PubMed

    Kim, J L; Elfman, L; Mi, Y; Wieslander, G; Smedje, G; Norbäck, D

    2007-04-01

    We investigated asthma and atopy in relation to microbial and plasticizer exposure. Pupils in eight primary schools in Uppsala (Sweden) answered a questionnaire, 1014 (68%) participated. Totally, 7.7% reported doctor-diagnosed asthma, 5.9% current asthma, and 12.2% allergy to pollen/pets. Wheeze was reported by 7.8%, 4.5% reported daytime breathlessness, and 2.0% nocturnal breathlessness. Measurements were performed in 23 classrooms (May-June), 74% had <1000 ppm CO(2) indoors. None had visible mold growth or dampness. Mean total microbial volatile organic compound (MVOC) concentration was 423 ng/m(3) indoors and 123 ng/m(3) outdoors. Indoor concentration of TMPD-MIB (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, Texanol) and TMPD-DIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate, TXIB), two common plasticizers, were 0.89 and 1.64 microg/m(3), respectively. MVOC and plasticizer concentration were correlated (r = 0.5; P < 0.01). Mold concentration was 360 cfu/m(3) indoors and 980 cfu/m(3) outdoors. At higher indoor concentrations of total MVOC, nocturnal breathlessness (P < 0.01) and doctor-diagnosed asthma (P < 0.05) were more common. Moreover, there were positive associations between nocturnal breathlessness and 3-methylfuran (P < 0.01), 3-methyl-1-butanol (P < 0.05), dimethyldisulfide (P < 0.01), 2-heptanone (P < 0.01), 1-octen-3-ol (P < 0.05), 3-octanone (P < 0.05), TMPD-MIB (P < 0.05), and TMPD-DIB (P < 0.01). TMPD-DIB was positively associated with wheeze (P < 0.05), daytime breathlessness (P < 0.05), doctor-diagnosed asthma (P < 0.05), and current asthma (P < 0.05). In conclusion, exposure to MVOC and plasticizers at school may be a risk factor for asthmatic symptoms in children. Despite generally good ventilation and lack of visible signs of mold growth, we found an association between respiratory symptoms and indoor MVOC concentration. In addition, we found associations between asthmatic symptoms and two common plasticizers. The highest levels of MVOC

  4. Some redox chemistry of HPO ⨪2 and ̽PO 2-3 radicals. A pulse radiolysis study

    NASA Astrophysics Data System (ADS)

    Packer, John E.; Anderson, Robert F.

    The HO̽ radical oxidises hypophosphite and phosphite anions to HPO ⨪2 and ̽PO 2-3 respectively, but Br ⨪2 and N̽ 3 do not. The rates of oxidation of HPO ⨪2 by a series of oxidising agents of known one electron redox potentials decrease with decreasing potential while the corresponding rates for oxidation of ̽PO 2-3 remain close to the diffusion controlled limit. ̽PO 2-3 will oxidise cysteine but HPO⨪ 2 does not. ̽PO 2-3 did not oxidise ABTS, ascorbate, or the anion of the vitamin E analogue, trolox. It reduced traces of TMPD +̽ in TMPD rather than oxidising the substrate. The one electron redox potentials for oxidation and reduction of ̽PO 2-3 are calculated in light of recently published redox data on penicillamine.

  5. The preparation of 3-substituted-1,5-dibromopentanes as precursors to heteracyclohexanes

    PubMed Central

    Ringstrand, Bryan; Oltmanns, Martin; Batt, Jeffrey A; Jankowiak, Aleksandra; Denicola, Richard P

    2011-01-01

    Summary The methodology to prepare 3-substituted 1,5-dibromopentanes I and their immediate precursors, which include 3-substituted 1,5-pentanediols VII or 4-substituted tetrahydropyrans VIII, is surveyed. Such dibromides I are important intermediates in the preparation of liquid crystalline derivatives containing 6-membered heterocyclic rings. Four dibromides 1a–1d containing simple alkyl and more complex fragments at the 3-position were prepared. 3-Propyl- and 3-pentyl-pentane-1,5-diol (2a,b) were prepared starting from either glutaconate or malonate diesters, while tetrahydropyrans 3c and 3d were obtained from tetrahydro-4H-pyran-4-one. The advantages and disadvantages of each route are discussed. Dibromides 1c and 1d were used to prepare sulfonium zwitterions 11c and 11d. PMID:21512596

  6. On the location of the H+-extruding steps in site 2 of the mitochondrial electron transport chain.

    PubMed

    Alexandre, A; Galiazzo, F; Lehninger, A L

    1980-11-25

    The location of the H+-translocating reactions within energy-conserving Site 2 of the mitochondrial electron transport chain was evaluated from two sets of data. In the first, the H+/2e- ejection ratios and Ca2+/2e- uptake ratios were compared for electron flow from succinate dehydrogenase, whose active site is on the matrix side of the inner membrane and from glycerol phosphate dehydrogenase, whose active site is on the cytosolic side. In intact rat liver mitochondria both substrates yielded H+/2e- ejection ratios close to 4.0 and Ca2+/2e- uptake ratios close to 1.0 during antimycin-sensitive reduction of ferricyanide. With rat liver mitoplasts and ferricytochrome c as electron acceptor, both substrates again gave the same stoichiometric ratios. The second approach involved determination of the sidedness of H+ formation during electron flow from succinate to ferricyanide via bypass of the antimycin block of the cytochrome b.c1 complex provided by N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), under conditions in which the TMPD-TMPD+ couple does not act as a membrane-penetrating protonophore. Electron flow in this system was inhibited by 2-then-oyltrifluoroacetone, indicating that TMPD probably accepts electrons from ubiquinol. The 2 H+ formed in this system were not delivered into the matrix but appeared directly in the medium in the absence of a protonophore. To accommodate the available evidence on Site 2 substrates, it is concluded that the substrate hydrogens are first transferred to ubiquinone, 2 H+ per 2e then appear in the medium by protolytic dehydrogenation of a species of ubiquinol or ubiquinol-protein having the appropriate sidedness (designated Site 2A), and the other 2 H+ are translocated from the matrix to the medium on passage of 2e- through the cytochrome b x c1 complex (designated Site 2B).

  7. Flat-Band Potential of n-Type Semiconducting Molybdenum Disulfide by Cyclic Voltammetry of Two-Electron Reductants: Interface Energetics and the Sustained Photooxidation of Chloride.

    DTIC Science & Technology

    1979-07-18

    Cyclic voltammetry has been used to locate the band edges of n-type MoS2 in CH3CN/ and EtOH/n-Bu4Nc104 solutions. The crucial experiments concern the...study of the cyclic voltammetry of biferrocene (BF) and N,N,N’,N’-tetramethyl-p-phenylenediamine (TMPD) each of which has two, reversible, one

  8. Na(+)-translocating cytochrome bo terminal oxidase from Vitreoscilla: some parameters of its Na+ pumping and orientation in synthetic vesicles.

    PubMed

    Park, C; Moon, J Y; Cokic, P; Webster, D A

    1996-09-10

    Vitreoscilla cytochrome bo ubiquinol oxidase is similar in some properties to the Escherichia coli enzyme, but unlike the latter, the Vitreoscilla oxidase functions as a primary Na+ pump. When purified Vitreoscilla cytochrome bo is incorporated into liposomes made from Vitreoscilla phospholipids and energized with a quinol substrate, it translocates Na+, not H+, across the vesicle membrane. Since protonophores CCCP (carbonyl cyanide m-chlorophenylhydrazone) and DTHB (3,5-di-tert-butyl-4-hydroxybenzaldehyde) stimulated the Na+ pumping, it is unlikely that it is a secondary effect due to the presence of Na+/H+ antiporter activity in the preparations. The efficiency of the Na+ pumping was 3.93 Na+ pumped per O2 consumed when ascorbate/TMPD was used as the substrate. The cytochrome has a K(m) and Kcat for Na+ of 2.9 mM and 277 s-1, respectively. When ferricytochrome c was entrapped within liposomes prepared from Vitreoscilla phospholipids, it was reduced by Q1H2 (ubiquinol-1) but not by ascorbate/TMPD (N,N,N',N'-tetramethyl-1,4-phenylenediamine). Although Q1H2 was oxidized by cytochrome bo in solution at a rate approximately 14 times that of the latter substrate, the rate of accumulation of Na+ within cytochrome bo vesicles driven by the membrane impermeable ascorbate/TMPD was 1.23 times that of the membrane permeable ubiquinol. These data allowed a calculation that in these synthetic proteoliposomes the cytochrome bo molecules are only 51% directed inward; a value of 61% inward-directed was estimated by measuring the ascorbate/TMPD oxidase activity of the proteoliposomes before and after disrupting them with Triton X-100. A random orientation of the E. coli cytochrome bo oxidase in proteoliposomes has also been reported.

  9. Mitochondrial Respiratory Chain Dysfunction in Dorsal Root Ganglia of Streptozotocin-Induced Diabetic Rats and Its Correction by Insulin Treatment

    PubMed Central

    Chowdhury, Subir K. Roy; Zherebitskaya, Elena; Smith, Darrell R.; Akude, Eli; Chattopadhyay, Sharmila; Jolivalt, Corinne G.; Calcutt, Nigel A.; Fernyhough, Paul

    2010-01-01

    OBJECTIVE Impairments in mitochondrial physiology may play a role in diabetic sensory neuropathy. We tested the hypothesis that mitochondrial dysfunction in sensory neurons is due to abnormal mitochondrial respiratory function. RESEARCH DESIGN AND METHODS Rates of oxygen consumption were measured in mitochondria from dorsal root ganglia (DRG) of 12- to- 22-week streptozotocin (STZ)-induced diabetic rats, diabetic rats treated with insulin, and age-matched controls. Activities and expression of components of mitochondrial complexes and reactive oxygen species (ROS) were analyzed. RESULTS Rates of coupled respiration with pyruvate + malate (P + M) and with ascorbate + TMPD (Asc + TMPD) in DRG were unchanged after 12 weeks of diabetes. By 22 weeks of diabetes, respiration with P + M was significantly decreased by 31–44% and with Asc + TMPD by 29–39% compared with control. Attenuated mitochondrial respiratory activity of STZ-diabetic rats was significantly improved by insulin that did not correct other indices of diabetes. Activities of mitochondrial complexes I and IV and the Krebs cycle enzyme, citrate synthase, were decreased in mitochondria from DRG of 22-week STZ-diabetic rats compared with control. ROS levels in perikarya of DRG neurons were not altered by diabetes, but ROS generation from mitochondria treated with antimycin A was diminished compared with control. Reduced mitochondrial respiratory function was associated with downregulation of expression of mitochondrial proteins. CONCLUSIONS Mitochondrial dysfunction in sensory neurons from type 1 diabetic rats is associated with impaired rates of respiratory activity and occurs without a significant rise in perikaryal ROS. PMID:20103706

  10. Conductivity Modifications of Graphene by Electron Donative Organic Molecules

    NASA Astrophysics Data System (ADS)

    Masujima, Hiroaki; Mori, Takehiko; Hayamizu, Yuhei

    2017-03-01

    Graphene has been studied for the application of transparent electrodes in flexible electrical devices with semiconductor organics. Control of the charge carrier density in graphene is crucial to reduce the contact resistance between graphene and the active layer of organic semiconductor. Chemical doping of graphene is an approach to change the carrier density, where the adsorbed organic molecules donate or accept electrons form graphene. While various acceptor organic molecules have been demonstrated so far, investigation about donor molecules is still poor. In this work, we have investigated doping effect in graphene field-effect transistors functionalized by organic donor molecules such as dibenzotetrathiafulvalene (DBTTF), hexamethyltetrathiafulvalene (HMTTF), 1,5-diaminonaphthalene (DAN), and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). Based on conductivity measurements of graphene transistors, the former three molecules do not have any significant effect to graphene transistors. However, TMPD shows effective n-type doping. The doping effect has a correlation with the level of highest occupied molecular orbital (HOMO) of each molecule, where TMPD has the highest HOMO level.

  11. Cyanide-resistant respiration in Euglena gracilis does not correlate with mitochondrial cytochrome O content

    SciTech Connect

    Devars, S.; Uribe, A.; Torres-Marquez, M.E.; Gonzalez-Halphen, D. ); Moreno-Sanchez, P. )

    1991-03-15

    Basal respiration Euglena gracilis cells grown in the dark with distinct carbon sources showed different sensitivity to KCN: 1-10% inhibition by 0.1 mM KCM for cells grown with glutamate+malate (g+m) and 40-55% for those grown with peptone+acetate (p+a). The basal respiration was stimulated 1.6 to 2.4 times by TMPD: the values reached by cells grown in g+m resembled those of p+a cells, suggesting a similar maximal cytochrome oxidase activity in both types. Dixon plots for KCM showed two components in basal and TMPD-stimulated respiration with K{sub i} values of 4-10 and 70-80 {mu}M for TMPC-stimulated respiration and 20-50 and 400-600 {mu}M for basal activity. Thus, the distinct sensitivities to KCN seems not to be due to a different content of aa{sub 3} in the cells, not to different K{sub i} for the inhibitor. Diphenyl amine, an inhibitor of alternate respiratory pathways, inhibited 85-95% basal respiration with a single K{sub i} value of 0.15-0.2 mM and 40-60% TMPD-stimulated activity. Determination of cytochrome o content, the postulated alternate oxidase, showed no differences in the cells grown with distinct carbon sources. Then the different sensitivity to cyanide is more likely related to the oxidation of different substrates.

  12. Preparation and Characterization of Macro- & Monomers for Azide & Alkyne Cycloaddition Polyerization

    USDA-ARS?s Scientific Manuscript database

    In 1970 Robert Harper and colleagues, showed that poly(ethylene oxide)s and Poly(propylene oxide)s (PEOs and PPOs, respectively) are effective softeners for cotton fabrics (Textile Chemist and Colorist, 1970, 2(1), 37-41. Using this information, we developed PEO and PPO dibromides and diepoxides to ...

  13. Synthesis of (±)-Bistellettadine A

    PubMed Central

    Yu, Min; Pochapsky, Susan S.

    2010-01-01

    Esterification of the trienoic acid with o-xylylene dibromide gave the bis ester that underwent a templated Diels-Alder reaction to afford the macrodiolide stereospecifically in a single step. The synthesis of bistellettadine A was completed in four steps by hydrolysis and side chain elaboration. PMID:20078082

  14. Removal of EDB and 1,2-DCA by Abiotic Reaction with Iron(II) Sulfide

    EPA Science Inventory

    Ethylene Dibromide (EDB) and 1,2-Dichloroethane (1,2-DCA) were used as lead scavengers in leaded motor gasoline in the USA until the late 1980s. Leaded gasoline in contact with ground water should produce concentrations of EDB near 1900 µg/L, and concentrations of 1,2-DCA near 3...

  15. 78 FR 12313 - Notice of Receipt of Requests To Voluntarily Cancel Certain Pesticide Registrations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ... name 000241-00391 Pendulum 3.3 Herbicide..... Pendimethalin. 000241-00403 Pendimethalin Manufacturing Pendimethalin. Concentrate Herbicide. 000264-00807 Calypso 70WG Insecticide... Thiacloprid. 000655-00802 Prentox Larva-Lur Contains Propoxur. Propoxur. 009688-00198 Chemsico Herbicide Prometon, Diquat dibromide...

  16. Removal of EDB and 1,2-DCA by Abiotic Reaction with Iron(II) Sulfide

    EPA Science Inventory

    Ethylene Dibromide (EDB) and 1,2-Dichloroethane (1,2-DCA) were used as lead scavengers in leaded motor gasoline in the USA until the late 1980s. Leaded gasoline in contact with ground water should produce concentrations of EDB near 1900 µg/L, and concentrations of 1,2-DCA near 3...

  17. 27 CFR 21.56 - Formula No. 29.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... intermediates. 551.Acetaldehyde. 552.Other aldehydes. 561.Ethyl ether. 562.Other ethers. 571.Ethylene dibromide... less than 20 percent acetaldehyde, or 1 gallon of ethyl acetate having an ester content of 100 percent... pounds if solid, or 1 gallon if liquid, of any chemical. When material other than acetaldehyde or...

  18. New Development of Polymer-Based Cotton for Breathable Material

    USDA-ARS?s Scientific Manuscript database

    Recently, we converted the poly (ethylene oxide) dibromide to poly (ethylene oxide) diazides and reacted to study cycloaddition polymerization with bisphenol-A dipropargyl ether to produce elastomers compatible with cotton (Polymer Preprints, 2005, 46(1), 737-738). The reactants were characterized w...

  19. Operation of platinum-palladium catalysts with leaded gasoline.

    PubMed Central

    Teague, D M; Clougherty, L B; Speca, A N

    1975-01-01

    The effect of various fuel additives on the ability of platinum-palladium catalytic converters to remove the carbon monoxide and hydrocarbon components of automotive exhaust has been examined. Engine dynamometer studies suggest that these catalysts may be successfully used in conjunction with fuels of relatively high tetraethyllead concentrations, provided the ethylene dibromide portion of the scavenger is excluded. PMID:50929

  20. SUCCESSFUL APPLICATION OF AIR SPARGING TO REMEDIATE ETHYLENE DEBROMIDE (EDB) IN GROUND WATER INKANSAS

    EPA Science Inventory

    Although Ethylene Dibromide (EDB) was banned in conventional motor fuel in the USA by 1990, EDB continues to contaminate ground water at many old gasoline service station sites. Although EDB contamination is widespread, there is little performance data on technology to remediat...

  1. Evaluation of Diquat against an acute experimental infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus

    USDA-ARS?s Scientific Manuscript database

    A trial was performed to evaluate the efficacy of diquat (6,7-Dihydrodipyrido[1,2-a:2',1'-c]pyrazinediium dibromide) against an acute experimental infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus. Diquat is an Environmental Protection Agency-approved herbicide and has t...

  2. Focused Feasibility Study Final Quality Assurance Program Plan

    DTIC Science & Technology

    1993-10-01

    other hydrocarbons attached, including specificaly: Ethylene Heptenes Cyclopentene Cyclodecene Propylene Octenes Cyclohexene Methylpentn Butylenes...8217 0.007’ Diquat 0.028 0.022 Endothall 0.18 0.16 Endrn 0.0022 0.00021 0.0022 Epichlorohydrin 02 Ethylene dibromide 02 0.00005’ Glyphosate 0.7d 0.7

  3. Cancer prevention: Strategies in the workplace

    SciTech Connect

    Becker, C.E.; Coye, M.J.

    1986-01-01

    This article discusses cancer prevention strategies for the workplace. Contents include: The exposure-potency index; ranking carcinogenic hazards of volatile industrial chemicals; ethylene dibromide toxicity and fatal consequences; danger of handling oncological agents, asbestos contamination of drinking water; sunlight and occupation skin cancer; smoking and occupational lung cancer; and controversies in the assessment of carcinogenic risk of formaldehyde.

  4. Potential hazards of fumigant residues.

    PubMed Central

    Fishbein, L

    1976-01-01

    A spectrum of fumigants (primarily ethylene dibromide, 1,2-dibromo-3-chloropropane, ethylene oxide, symdibromotetetrachloroethane, 1,3-dichloropropene, dichlorovos, carbon tetrachloride, methyl bromide) as well as their degradation products in foodstuffs and soil have been examined mainly in regard to the potential mutagenicity of their residues. PMID:789068

  5. Adsorption on bacterial spores depending on the aggregation properties of antimicrobial tensides.

    PubMed

    Cupková, V; Devínsky, F; Mlynarcík, D; Lacko, I; Bittererová, J

    1991-01-01

    A change in interaction with spores of Bacillus cereus occurred in the range of critical concentrations of micelle formation. With 1-methyldodecyldimethylamine-N-oxide and N,N'-bis(dodecyldimethyl)-1,2-ethanediammonium dibromide, the induced release of dipicolinic acid was blocked and the adsorption dynamics changed, respectively.

  6. SUCCESSFUL APPLICATION OF AIR SPARGING TO REMEDIATE ETHYLENE DEBROMIDE (EDB) IN GROUND WATER INKANSAS

    EPA Science Inventory

    Although Ethylene Dibromide (EDB) was banned in conventional motor fuel in the USA by 1990, EDB continues to contaminate ground water at many old gasoline service station sites. Although EDB contamination is widespread, there is little performance data on technology to remediat...

  7. 40 CFR Table 8 to Subpart Ggg of... - Fraction Measured (Fm) for HAP Compounds in Wastewater Streams

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Ethylene dibromide (Dibromomethane) 106934 1.00 Ethylene glycol dimethyl ether 110714 0.86 Ethylene glycol monobutyl ether acetate 112072 0.043 Ethylene glycol monomethyl ether acetate 110496 0.093 Ethylene oxide... Dichloroethane (1,2-) (Ethylene dichloride) 107062 1.00 Dichloroethylether (Bis(2-Chloroethyl ether)) 111444 0.76...

  8. 40 CFR Table 9 to Subpart G of... - Organic HAP's Subject to the Wastewater Provisions for Process Units at New and Existing Sources...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Ethylene dibromide (Dibromomethane) 106934 0.99 Ethylene glycol dimethyl ether 110714 0.90 Ethylene glycol monobutyl ether acetate 112072 0.76 Ethylene glycol monomethyl ether acetate 110496 0.28 Ethylene oxide...-) (Ethylene dichloride) 107062 0.99 Dichloroethyl ether (Bis(2-chloroethyl)ether) 111444 0.87 Dichloropropene...

  9. Light-induced generation of electric potential difference in membranes of purple and green sulfur bacteria.

    PubMed

    Krasinskaya, N P; Samuilov, V D

    1977-06-01

    When associated with a planar phospholipid membrane, chromatophores isolated from photosynthetic sulfur bacteria Chromatium minutissimum, Ectothiorhodospira shaposhnikovii, and Chlorobium limicola f. thiosulfatophilum were shown to generate a light-induced transmembrane electric potential difference measured by a direct method using macroelectrodes and a voltmeter. The maximal photoelectric responses were observed upon the addition of 1,4-naphthoquinone in combination with phenazine methosulfate (or TMPD) and ascorbate. The photoeffects were inhibited by CCCP and gramicidin. The data demonstrate that similar mechanisms of photoelectric generation function in membranes of the different bacteria studied.

  10. [Arrhenius diagrams of respiratory enzymes of liver mitochondria from bass (Morone labrax)].

    PubMed

    Borgatti, A R; Trigari, G; Pagliarani, A; Ventrella, V

    1982-12-15

    Arrhenius plot of glutamate, succinate and ascorbate+TMPD oxidation in bass liver mitochondria show a break at different temperatures. Above the break activation energies (Ea) of the three enzymes. Above the break activation energies (Ea) of the three enzymes examined are similar and comparable with literature data in poikilotermic and homeothermic animals. Below the break the Ea are again comparable with poikiloterm and homeotherm ones except for succinate-oxidase whose Ea is surprisingly higher. The data are suggested to be due to the features of the enzymes or to the microenvironmental physical state.

  11. Matrix isolation and ESR study of unstable intermediate generated by radiation techniques from metal carbonyl complexes

    NASA Astrophysics Data System (ADS)

    Buttafava, A.; Faucitano, A.; Martinotti, F.

    Exposure of MeTHF solutions of M(CO) 6 (M=Cr, Mo, W) to γ-rays or photoionization with TMPD at 77 K gives paramagnetic species attributed to 17 electron radical anions M(CO) overlineṡ. The excess energy arising from the primary electron capture process is responsible of the fast M—CO bond breaking which prevents the trapping of 19-electron species M(CO) overlineṡ. Experimental and EHT-MO calculated g-tensors of the pentacoordinated anions are consistent with a square pyramidal C4ν structure having the unpaired electron in a molecular orbital with a high dz2 character.

  12. Root-knot Nematode Management and Yield of Soybean as Affected by Winter Cover Crops, Tillage Systems, and Nematicides.

    PubMed

    Minton, N A; Parker, M B

    1987-01-01

    Management of Meloidogyne incognita on soybean as affected by winter small grain crops or fallow, two tillage systems, and nematicides was studied. Numbers of M. incognita did not differ in plots planted to wheat and rye. Yields of soybean planted after these crops also did not differ. Numbers of M. incognita were greater in fallow than in rye plots, but soybean yield was not affected by the two treatments. Soybean yields were greater in subsoil-plant than in moldboard plowed plots. Ethylene dibromide reduced nematode population densities more consistently than aldicarb and phenamiphos. Also, ethylene dibromide increased yields the most and phenamiphos the least. There was a positive correlation (P = 0.001) of seed size (weight of 100 seeds) with yield (r = 0.79), indicating that factors affecting yield also affected seed size.

  13. Health-hazard evaluation report HETA 84-311-1575, grain elevators, Superior, Wisconsin, and Duluth, Minnesota

    SciTech Connect

    Ahrenholz, S.H.

    1985-04-01

    Personal air samples were analyzed for carbon disulfide, ethylene dibromide, carbon tetrachloride, and grain dust at grain elevators. The survey was requested by a representative of Local 118 of the American Federation of Grain Millers to evaluate exposures to grain fumigants and dust among workers at the two sites. All concentrations of carbon disulfide, carbon tetrachloride, and ethylene dibromide were below the detection limit. Grain-dust concentrations ranged from 0.34 to 38 milligrams per cubic meter (mg/m/sup 3/). The American Conference of Governmental Industrial Hygienists threshold limit value for airborne grain dust is 4 mg/m/sup 3/. Short-term sampling for the fumigants was performed; however, the results were inconclusive. The author concludes that a health hazard due to overexposure to grain dust exists at the grain elevators. Recommendations were made.

  14. Current Intelligence Bulletins: summaries, September 1987

    SciTech Connect

    Not Available

    1987-09-01

    Brief summaries of 49 NIOSH Current Intelligence Bulletins were provided in a cumulative listing. Permissible Exposure Limits were included where applicable, and notes were provided with some summaries indicating further action or data since original publication. Topics covered include chloroprene, trichloroethylene, ethylene-dibromide, chrome pigment, asbestos, hexamethylphosphoric-triamide, polychlorinated-biphenyls, 4,4'-diaminodiphenylmethane, chloroform, radon daughters, dimethylcarbamoyl-chloride, diethylcarbamoyl-chloride, explosive azide hazard, arsenic, nitrosamines, metabolic precursors of beta-naphthylamine, 2-nitropropane, acrylonitrile, 2,4-diaminoanisole, tetrachloroethylene, trimellitic-anhydride, ethylene-thiourea, ethylene-dibromide, disulfiram, dyes, ethylene-dichloride, chloroethanes, vinyl halides, glycidyl ethers, epichlorohydrin, smoking, arsine, radiofrequency sealers, formaldehyde, ethylene-oxide, silica flour, vibration syndrome, glycol ethers, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,3-butadiene, cadmium, monohalomethanes, dinitrotoluenes, methylene-chloride, 4,4'-methylenedianiline, organic solvents, and injuries and amputations from working with power presses.

  15. Degradation of halogenated aliphatic compounds by the ammonia-oxidizing bacterium nitrosomonas europaea

    SciTech Connect

    Vannelli, T.; Logan, M.; Arciero, D.M.; Hooper, A.B. )

    1990-04-01

    Suspensions of Nitrosomonas europaea catalyzed the ammonia-stimulated aerobic transformation of the halogenated aliphatic compounds dichloromethane, dibromomethane, trichloromethane (chloroform), bromoethane, 1,2-dibromoethane (ethylene dibromide), 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochloroethylene (vinyl chloride), gem-dichloroethylene, cis- and trans-dichloroethylene, cis-dibromoethylene, trichloroethylene, and 1,2,3-trichloropropane. Tetrachloromethane (carbon tetrachloride), tetrachloroethylene (perchloroethylene), and trans-dibromoethylene were not degraded.

  16. Degradation of halogenated aliphatic compounds by the ammonia-oxidizing bacterium Nitrosomonas europaea

    SciTech Connect

    Vannelli, T.; Logan, M.; Arciero, D.M.; Hooper, A.B.

    1990-01-01

    Suspensions of Nitrosomonas europaea catalyzed the ammonia-stimulated aerobic transformation of the halogenated aliphatic compounds dichloromethane, dibromomethane, trichloromethane (chloroform), bromoethane, 1,2-dibromoethane (ethylene dibromide), 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochloroethylene (vinyl chloride), gem-dichloroethylene, cis- and trans-dichloroethylene, cis-dibromoethylene, trichloroethylene, and 1,2,3-trichloropropane. Tetrachloromethane (carbon tetrachloride), tetrachloroethylene (perchloroethylene), and trans-dibromoethylene were not degraded.

  17. Pretreatment with pyridinium oximes improves antidotal therapy against tabun poisoning.

    PubMed

    Lucić Vrdoljak, Ana; Calić, Maja; Radić, Bozica; Berend, Suzana; Jun, Daniel; Kuca, Kamil; Kovarik, Zrinka

    2006-11-10

    Oximes K033 [1,4-bis(2-hydroxyiminomethylpyridinium) butane dibromide] and K048 [1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium) butane dibromide] were tested as pretreatment drugs in tabun-poisoned mice followed by treatment with atropine plus K033, K048, K027 [1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide], TMB-4 [1,3-bis(4-hydroxyiminomethylpyridinium) propane dibromide] and HI-6 [(1-(2-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium)-2-oxapropane dichloride)]. Oxime doses of 25% or 5% of its LD(50) were used for pretreatment 15 min before tabun-poisoning and for treatment 1 min after tabun administration to mice. The best therapeutic effect was obtained when oxime K048 (25% of its LD(50)) was used in both pretreatment and treatment with atropine. This regiment insured survival of all tested animals after the application of 10 LD(50) of tabun. In addition, since butyrylcholinesterase (BChE; EC 3.1.1.8) is considered an endogenous bioscavenger of anticholinesterase compounds and its interactions with oximes could be masked by AChE interactions, we evaluated kinetic parameters for interactions of tested oximes with native and tabun-inhibited human plasma BChE and compared them with results obtained previously for human erythrocyte acetylcholinesterase (AChE; EC 3.1.1.7). Progressive inhibition of BChE by tabun was slightly faster than that of AChE. The reactivation of tabun-inhibited BChE by oximes was very slow, and BChE binding affinity for oximes was lower than AChE's. Therefore, BChE could scavenge tabun prior to AChE inhibition, but fast oxime-assisted reactivation of tabun-inhibited AChE or protection of AChE by oxime against inhibition with tabun would not be obstructed by interaction between BChE and oximes.

  18. Synthesis of Energetic Materials

    DTIC Science & Technology

    1988-03-01

    the diacetoxy pyrazine reacted with urea to give a bicyclic urea derivative, which was nitrated with nitric acid-acetic anhydride to yield the...imidazolidine and pyrazine dibromides, work with these compounds was discontinued. 3 Scheme I. Bic yclicnitramine Carbonates and Derivatives No&M CkH--3 0 O> Nu O... pyrazine . We anticipated that a more basic nitrogen species, such as an amide, used in excess, might intercept these cations, thus supressing the

  19. Pathogenicity of Macroposthonia xenoplax to Walnut

    PubMed Central

    Lownsbery, B. F.; Moody, E. H.; Moretto, A.; Noel, G. R.; Burlando, T. M.

    1978-01-01

    Preplanting treatment of soil naturally infested with Macroposthonia xenoplax with 1,2-dibromoethane (ethylene dibromide) significantly increased the growth rate of Juglans hindsii seedlings. When seedlings of J. hindsii, J. regia CV "Serf" and J. regia CV Eureka were inoculated with M. xenoplax, their growth was signilicantly less than that of nematode-free controls. This retarded growth rate was accompanied hy feeder root necrosis, longitudinal cracks in the older roots, and distinct lesions in the secondary phloem. PMID:19305847

  20. The application of a monolithic triphenylphosphine reagent for conducting Ramirez gem-dibromoolefination reactions in flow

    PubMed Central

    Roper, Kimberley A; Berry, Malcolm B

    2013-01-01

    Summary The application of a monolithic form of triphenylphosphine to the Ramirez gem-dibromoolefination reaction using flow chemistry techniques is reported. A variety of gem-dibromides were synthesised in high purity and excellent yield following only removal of solvent and no further off-line purification. It is also possible to perform the Appel reaction using the same monolith and the relationship between the mechanisms of the two reactions is discussed. PMID:24062843

  1. Antidotal treatment of GF-agent intoxication in mice with bispyridinium oximes.

    PubMed

    Sevelová, Lucie; Kuca, Kamil; Krejcová-Kunesová, Gabriela

    2005-02-01

    It was shown that intoxications with GF-agent are rather resistant to convential oxime therapy; therefore, the development of new oximes in an effort to improve this unsatisfactory situation continues. Upon screening in vitro reactivation test for oximes, that were either newly synthesized at our department, or those that have never been tested for reactivation of GF-inhibited acetylcholinesterase (AChE), three oximes {(1,4-bis(4-hydroxyiminomethylpyridinium)butane dibromide) (K033); (1-(2-hydroxyiminomethylpyridinium)-3-(3-carbamoylpyridinium)-2-oxa-propane dichloride) (HS-6); and (1-(2-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium)-but-2-ene dibromide) (BI-6)} with the highest reactivation potency were chosen for in vivo testing in our study. 1,3-Bis(4-hydroxyiminomethylpyridinium)-2-oxa-propane dibromide) (obidoxime); (1-(2-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium)-2-oxa-propane dichloride) (HI-6); and (1,1-bis(4-hydroxyiminomethylpyridinium)-methane dibromide) (methoxime) were chosen for comparison as a standard antidotal treatment. All the oximes were applied at the same proportion of their LD50 value (5%), and because of the different acute toxicity of the oximes, the molar concentrations of their solutions for intramuscular (i.m.) administration were considerably different. The highest therapeutic ratio was achieved for therapeutic regimen consisting of HI-6 and atropine. The significantly (P < 0.05) lowest effectivity in treatment of supralethal GF-agent poisoning in comparison with all the other therapeutic regimens, was surprisingly observed for methoxime. HS-6, K033 and BI-6 as well as obidoxime were comparably effective antidotes against GF-agent intoxication and their therapeutic ratios were similar.

  2. The application of a monolithic triphenylphosphine reagent for conducting Ramirez gem-dibromoolefination reactions in flow.

    PubMed

    Roper, Kimberley A; Berry, Malcolm B; Ley, Steven V

    2013-01-01

    The application of a monolithic form of triphenylphosphine to the Ramirez gem-dibromoolefination reaction using flow chemistry techniques is reported. A variety of gem-dibromides were synthesised in high purity and excellent yield following only removal of solvent and no further off-line purification. It is also possible to perform the Appel reaction using the same monolith and the relationship between the mechanisms of the two reactions is discussed.

  3. Research on Colorant Systems Whose Characteristics May Be Reversed

    DTIC Science & Technology

    1974-06-01

    electrochromic display devices . Other similar c:ompounds have also been used for slmilar usege, and Jince they are of different. colors according to the...problem was not a profitable one. In view of the successful operation of other devices described in this report, the pursuance of the... viologen dibromide that gives a purple color. Since the dark blue color deposits on the electrode, the viologen derivatives can be used either as

  4. A comparative study on the solubility and stability of p-phenylenediamine-based organic redox couples for non-aqueous flow batteries

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-seung; Lee, Keon-Joon; Han, Young-Kyu; Ryu, Ji Heon; Oh, Seung M.

    2017-04-01

    A methyl-substituted p-phenylenediamine (PD), N,N,N‧,N‧-tetramethyl-p-phenylenediamine (TMPD), is examined as a positive redox couple with high energy density for non-aqueous Li-flow batteries. Methyl substitution affects the solubility of the redox couple, as the solubility is increased by a factor of ten, to a maximum solubility of 5.0 M in 1.0 M lithium tetrafluoroborate-propylene carbonate supporting electrolyte due to elimination of the hydrogen bonding between the solute molecules. The methyl substitution also enhances the chemical stability of the cation radical and di-cation being generated from PD, as the redox center is shielded by the methyl groups. Furthermore, this organic redox couple demonstrate two-electron redox reactions at 3.2 and 3.8 V (vs. Li/Li+); therefore, the volumetric capacity is twice higher compared to conventional one-electron involved redox couples. In a non-flowing Li/TMPD coin-cell, this organic redox couple demonstrates very stable cycleability as a positive redox couple for non-aqueous flow batteries.

  5. The different behaviors of three oxidative mediators in probing the redox activities of the yeast Saccharomyces cerevisiae.

    PubMed

    Zhao, Jinsheng; Wang, Min; Yang, Zhenyu; Wang, Zhong; Wang, Huaisheng; Yang, Zhengyu

    2007-07-30

    The different behaviors of three lipophilic mediators including 2-methyl-1,4-naphthalenedione(menadione), 2,6-dichlorophenolindophenol (DCPIP) and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) in probing the redox activity of the yeast Saccharomyces cerevisiae were studied by several comparative factor-influencing experiments. Hydrophilic ferricyanide was employed as an extracellular electron acceptor, and constituted dual mediator system with each of three lipophilic mediators. Limiting-current microelectrode voltammetry was used to measure the quantity of ferrocyanide accumulations, giving a direct measure of the redox activity. It was found that under anaerobic condition, menadione interacts with anaerobic respiration pathway, whereas DCPIP and TMPD interact with fermentation pathway in the yeast. Based on the understanding of the interaction between the yeast and each of three mediators, three mediators were respectively employed in evaluating the toxicity of acetic acid on S. cerevisiae and, the results for the first showed that the mediators are complementary to each other when used as electron carriers in biotoxicity assay.

  6. Fully printed flexible and disposable wireless cyclic voltammetry tag.

    PubMed

    Jung, Younsu; Park, Hyejin; Park, Jin-Ah; Noh, Jinsoo; Choi, Yunchang; Jung, Minhoon; Jung, Kyunghwan; Pyo, Myungho; Chen, Kevin; Javey, Ali; Cho, Gyoujin

    2015-01-29

    A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to -500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health.

  7. Fully printed flexible and disposable wireless cyclic voltammetry tag

    PubMed Central

    Jung, Younsu; Park, Hyejin; Park, Jin-Ah; Noh, Jinsoo; Choi, Yunchang; Jung, Minhoon; Jung, Kyunghwan; Pyo, Myungho; Chen, Kevin; Javey, Ali; Cho, Gyoujin

    2015-01-01

    A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to −500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health. PMID:25630250

  8. Tetrahydrocannabinol induces brain mitochondrial respiratory chain dysfunction and increases oxidative stress: a potential mechanism involved in cannabis-related stroke.

    PubMed

    Wolff, Valérie; Schlagowski, Anna-Isabel; Rouyer, Olivier; Charles, Anne-Laure; Singh, François; Auger, Cyril; Schini-Kerth, Valérie; Marescaux, Christian; Raul, Jean-Sébastien; Zoll, Joffrey; Geny, Bernard

    2015-01-01

    Cannabis has potential therapeutic use but tetrahydrocannabinol (THC), its main psychoactive component, appears as a risk factor for ischemic stroke in young adults. We therefore evaluate the effects of THC on brain mitochondrial function and oxidative stress, key factors involved in stroke. Maximal oxidative capacities V max (complexes I, III, and IV activities), V succ (complexes II, III, and IV activities), V tmpd (complex IV activity), together with mitochondrial coupling (V max/V 0), were determined in control conditions and after exposure to THC in isolated mitochondria extracted from rat brain, using differential centrifugations. Oxidative stress was also assessed through hydrogen peroxide (H2O2) production, measured with Amplex Red. THC significantly decreased V max (-71%; P < 0.0001), V succ (-65%; P < 0.0001), and V tmpd (-3.5%; P < 0.001). Mitochondrial coupling (V max/V 0) was also significantly decreased after THC exposure (1.8±0.2 versus 6.3±0.7; P < 0.001). Furthermore, THC significantly enhanced H2O2 production by cerebral mitochondria (+171%; P < 0.05) and mitochondrial free radical leak was increased from 0.01±0.01 to 0.10±0.01% (P < 0.001). Thus, THC increases oxidative stress and induces cerebral mitochondrial dysfunction. This mechanism may be involved in young cannabis users who develop ischemic stroke since THC might increase patient's vulnerability to stroke.

  9. Differential effects of endurance training and creatine depletion on regional mitochondrial adaptations in rat skeletal muscle.

    PubMed Central

    Roussel, D; Lhenry, F; Ecochard, L; Sempore, B; Rouanet, J L; Favier, R

    2000-01-01

    To examine the combined effects of 2-week endurance training and 3-week feeding with beta-guanidinopropionic acid (GPA) on regional adaptability of skeletal muscle mitochondria, intermyofibrillar mitochondria (IFM) and subsarcolemmal mitochondria (SSM) were isolated from quadriceps muscles of sedentary control, trained control, sedentary GPA-fed and trained GPA-fed rats. Mitochondrial oxidative phosphorylation was assessed polarographically by using pyruvate plus malate, succinate (plus rotenone), and ascorbate plus N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) (plus antimycin) as respiratory substrates. Assays of cytochrome c oxidase and F(1)-ATPase activities were also performed. In sedentary control rats, IFM exhibited a higher oxidative capacity than SSM, whereas F(1)-ATPase activities were similar. Training increased the oxidative phosphorylation capacity of mitochondria with both pyruvate plus malate and ascorbate plus TMPD as substrates, with no differences between IFM and SSM. In contrast, the GPA diet mainly improved the overall SSM oxidative phosphorylation capacity, irrespective of the substrate used. Finally, the superimposition of training to feeding with GPA strongly increased both oxidase and enzymic activities in SSM, whereas no cumulative effects were found in IFM mitochondria. It therefore seems that endurance training and feeding with GPA, which are both known to alter the energetic status of the muscle cell, might mediate distinct biochemical adaptations in regional skeletal muscle mitochondria. PMID:10947970

  10. Programmed cell death in plants: protective effect of phenolic compounds against chitosan and H2O2.

    PubMed

    Samuilov, V D; Vasil'ev, L A; Dzyubinskaya, E V; Kiselevsky, D B; Nesov, A V

    2010-02-01

    Addition of chitosan or H2O2 caused destruction of nuclei of epidermal cells (EC) in the epidermis isolated from pea leaves. Phenol, a substrate of the apoplastic peroxidase-oxidase, in concentrations of 10(-10)-10(-6) M prevented the destructive effect of chitosan. Phenolic compounds 2,4-dichlorophenol, catechol, and salicylic acid, phenolic uncouplers of oxidative phosphorylation pentachlorophenol and 2,4-dinitrophenol, and a non-phenolic uncoupler carbonyl cyanide m-chlorophenylhydrazone, but not tyrosine or guaiacol, displayed similar protective effects. A further increase in concentrations of the phenolic compounds abolished their protective effects against chitosan. Malate, a substrate of the apoplastic malate dehydrogenase, replenished the pool of apoplastic NADH that is a substrate of peroxidase-oxidase, prevented the chitosan-induced destruction of the EC nuclei, and removed the deleterious effect of the increased concentration of phenol (0.1 mM). Methylene Blue, benzoquinone, and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) capable of supporting the optimal catalytic action of peroxidase-oxidase cancelled the destructive effect of chitosan on the EC nuclei. The NADH-oxidizing combination of TMPD with ferricyanide promoted the chitosan-induced destruction of the nuclei. The data suggest that the apoplastic peroxidase-oxidase is involved in the antioxidant protection of EC against chitosan and H2O2.

  11. Toxicological properties of trialkyl phosphorothioate and dialkyl alkyl- and arylphosphonothioate esters.

    PubMed

    Fukuto, T R

    1983-01-01

    Impurities such as O,S,S-trimethyl phosphorodithioate (TMPD) and the S-methyl isomer of malathion (isomalathion) strongly potentiated the mammalian toxicity of malathion. In contrast, impurities present in the phosphoramidothioate insecticide acephate had an antagonizing effect on its mammalian toxicity. The potentiation of the toxicity of malathion was attributed to inhibition of mammalian liver and serum carboxylesterase. O,O,S-Trimethyl phosphorothioate (TMP), another impurity present in technical malathion and in other organophosphorus insecticides, proved to be highly toxic. Rats given a single oral dose of TMP at a level as low as 20 mg/kg died over a period of three weeks, with death occurring with non-cholinergic signs of poisoning. TMPD also caused similar delayed death in rats. O,O,O-Trimethyl phosphorothioate (TMP=S), also another impurity in technical malathion and a structural isomer of TMP, was a potent antagonist to the delayed toxicity of TMP. Examination of a number of related trialkyl phosphorothioate and dialkyl alkylphosphonothioate esters revealed several of these compounds to be highly toxic to rats.

  12. Construction and characterization of a mutant of alkaliphilic Bacillus firmus OF4 with a disrupted cta operon and purification of a novel cytochrome bd.

    PubMed Central

    Gilmour, R; Krulwich, T A

    1997-01-01

    The caa3-type terminal oxidase of Bacillus firmus OF4 has been proposed to play an important role in the growth and bioenergetics of this alkaliphile (A. A. Guffanti and T. A. Krulwich, J. Biol. Chem. 267:9580-9588, 1992). A mutant strain was generated in which the cta operon encoding the oxidase was disrupted by insertion of a spectinomycin resistance cassette. The mutant was unable to oxidize ascorbate in the presence of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). Absorption spectra of membranes confirmed the loss of the enzyme and indicated the presence of a cytochrome bd-type terminal oxidase. The mutant could grow on glucose but was unable to grow on malate or other nonfermentative carbon sources, despite the presence of the cytochrome bd. The cytochrome bd was purified from the mutant. The enzyme consisted of two subunits and, with menadiol as substrate, consumed oxygen with a specific activity of 12 micromol of O2 x min(-1) x mg(-1). In contrast to both cytochromes bd of Escherichia coli, the enzyme did not utilize TMPD as an electron source. A number of additional features, including subunit size and spectral properties, distinguish this cytochrome bd from its counterparts in E. coli and Azotobacter vinelandii. PMID:9006044

  13. Fully printed flexible and disposable wireless cyclic voltammetry tag

    NASA Astrophysics Data System (ADS)

    Jung, Younsu; Park, Hyejin; Park, Jin-Ah; Noh, Jinsoo; Choi, Yunchang; Jung, Minhoon; Jung, Kyunghwan; Pyo, Myungho; Chen, Kevin; Javey, Ali; Cho, Gyoujin

    2015-01-01

    A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to -500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health.

  14. Analysis of sulfonamides, trimethoprim, fluoroquinolones, quinolones, triphenylmethane dyes and methyltestosterone in fish and shrimp using liquid chromatography-mass spectrometry.

    PubMed

    Storey, Joseph M; Clark, Susan B; Johnson, Aaron S; Andersen, Wendy C; Turnipseed, Sherri B; Lohne, Jack J; Burger, Robert J; Ayres, Patrick R; Carr, Justin R; Madson, Mark R

    2014-12-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening method is described for the detection and identification of 26 veterinary drugs in fish and other aquaculture products. The analytes include: 13 sulfonamides, trimethoprim, 3 fluoroquinolones, 3 quinolones, 3 triphenylmethane dyes, 2 leuco dye metabolites, and 1 hormone. In this method, tissue is mixed with EDTA-McIlvaine buffer, double-extracted with acetonitrile, p-toluenesulfonic (p-TSA) acid and N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD), and analyzed using LC-MS/MS. Inclusion of p-TSA and TMPD in the extraction procedure was critical for simultaneous analysis of dyes with the other groups of veterinary drugs. The proposed procedure was validated as both a quantitative analysis method and as a semi-quantitative screening method for multiple fish and shrimp matrices. The method was applied to eight types of fish (catfish, eel, pangasius, sablefish, tilapia, swai, salmon, and trout) and shrimp at the appropriate level of concern: 10ng/g for sulfonamides, trimethoprim, and quinolones, 5ng/g for fluoroquinolones, 1ng/g for dyes and their metabolites, and 0.4ng/g for methyltestosterone.

  15. Bypasses of the antimycin a block of mitochondrial electron transport in relation to ubisemiquinone function.

    PubMed

    Alexandre, A; Lehninger, A L

    1984-10-26

    Two different bypasses around the antimycin block of electron transport from succinate to cytochrome c via the ubiquinol-cytochrome c oxidoreductase of intact rat liver mitochondria were analyzed, one promoted by N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and the other by 2,6-dichlorophenolindophenol (DCIP). Both bypasses are inhibited by myxothiazol, which blocks electron flow from ubiquinol to the Rieske iron-sulfur center, and by 2-hydroxy-3-undecyl-1,4-naphthoquinone, which inhibits electron flow from the iron-sulfur center to cytochrome c1. In the bypass promoted by TMPD its oxidized form (Wurster's blue) acts as an electron acceptor from some reduced component prior to the antimycin block, which by exclusion of other possibilities is ubisemiquinone. In the DCIP bypass its reduced form acts as an electron donor, by reducing ubisemiquinone to ubiquinol; reduced DCIP is regenerated again at the expense of either succinate or ascorbate. The observations described are consistent with and support current models of the Q cycle. Bypasses promoted by artificial electron carriers provide an independent approach to analysis of electron flow through ubiquinol-cytochrome c oxidoreductase.

  16. Current Intelligence Bulletins: summaries

    SciTech Connect

    Not Available

    1986-07-24

    Summaries are provided for the 47 Current Intelligence Bulletins issued to date by NIOSH; any revisions in NIOSH policy made after a bulletin was issued are included. Subjects of the bulletins include the following: chloroprene; trichloroethylene; ethylene-dibromide; chrome pigment; asbestos exposure; hexamethylphosphoric-triamide; polychlorinated biphenyls; 4,4'-diaminodipheylmethane; chloroform; radon daughters; dimethylcarbamoyl-chloride; diethylcarbamoyl-chloride; explosive azide hazard; inorganic arsenic; nitrosamines; metabolic precursors of beta-naphtylamine; 2-nitropropane; acryonitrile; 2,4-diaminoanisole; tetrachloroethylene; trimellitic-anhydride; ethylene-thiourea; ethylene-dibromide and disulfiram, toxic interaction; direct blue 6, direct black 38, direct brown 95, benzidine derived dyes; ethylene-dichloride; NIAX catalyst ESN; chloroethanes, review of toxicity; vinyl halides, carcinogenicity; glycidyl ethers; epichlorohydrin; smoking and the occupational environment; arsine poisoning in the workplace; radiofrequency sealers and heaters; formaldehyde; ethylene-oxide; silica flour; ethylene-dibromide; vibration syndrome; glycol ethers; 2,3,7,8-tetrachlorodibenzo-p-dioxin; 1,3-butadiene; cadmium; monohalomethanes; dinitrotoluenes; polychlorinated biphenyls in electrical equipment fires or failures; methylene-chloride; and 4,4' methylenedianiline.

  17. Anion- and pH-dependent activation of the soluble form of dopamine beta-hydroxylase.

    PubMed

    Terland, Ole; Flatmark, Torgeir

    2003-02-01

    The present study presents evidence for the conclusion that the catalytic activity of dopamine beta-hydroxylase (DBH; dopamine beta-mono-oxygenase, EC 1.14.17.1) is regulated independently by pH and by anions. In the absence of activating anions (i.e. in 50 mM Mes buffer) the activity was essentially zero at low pH (5.1-5.3) when assayed with the artificial electron donors ferrocyanide (0.25 mM), N, N, N', N'-tetramethyl-p-phenylenediamine (TMPD, 2 mM) or N, N-dimethyl-p-phenylenediamine (1 mM) and tyramine (8 mM) as the substrate to be hydroxylated. However, in the presence of activating anions (e.g. 0.05-0.6 M Cl(-) in 50 mM Mes buffer, 0.1 M phosphate buffer or 0.2 M acetate buffer) a high catalytic activity was observed at pH 5.1-5.3. The pronounced effect of anions at this pH may be related to the postulated anion-induced conformational change of DBH [Syvertsen, Melø and Ljones (1987) Biochim. Biophys. Acta 914, 6-18] resulting in a facilitated access of the substrates to the active site(s). The anion-activated DBH was inhibited when assayed with ferrocyanide and activated when assayed with TMPD as electron donors by increasing the pH (5.1 to 6.0). By contrast, in the absence of anions the activity increased from essentially zero at pH 5.1-5.3 to high values at pH 6.0, irrespective of the electron donor used. The data suggest that the conformational change induced by anion activation exposes a negatively charged group at or near the electron-donor-binding site(s) imposing an electrostatic repulsion towards ferrocyanide (four negative charges) and an electrostatic attraction towards the positively charged TMPD, thus explaining the different pH-activity curves obtained for the two electron donors. In contrast to the artificial electron donors, the physiological donor ascorbate [Terland and Flatmark (1975) FEBS Lett. 59, 52-56] supports hydroxylation of tyramine at low pH also in the absence of Cl(-), acetate or phosphate, confirming that ascorbate also

  18. Effects of allelopathic compounds of corn pollen on respiration and cell division of watermelon.

    PubMed

    Cruz Ortega, R; Anaya, A L; Ramos, L

    1988-01-01

    The effects of the allelopathic compounds of an "'ethanolic extract" of corn pollen on growth, respiration, and cellular division of watermelon (Citrullus lanatus, var. peacock improved) were studied. Bioassays with the ethanolic extract showed an inhibition of radicle and hypocotyl growth. The effects on respiration were observed in isolated watermelon hypocotyl mitochondria. The ethanolic extract acts as an inhibitor of the electron pathway, decreasing oxygen consumption in state 3, with malate and succinate substrates. The specific inhibition site probably is located before the cytochromec. Ascorbate-TMPD as substrate reversed the inhibitory effect of the ethanolic extract. An evaluation of the mitotic index was made in slide preparations of previously treated meristematic cells. A decrease in mitotic activity of more than 50% was found, as well as irregular and pycnotic nuclei. The data obtained from this study reflect an important mechanism of action of the allelopathic compounds of corn pollen.

  19. [Reconstruction of the function of membrane potential formation by isolated pigment-protein complexes of Rhodospirillum rubrum].

    PubMed

    Barskiĭ, E L; Kondrashin, A A; Samuilov, V D; Skulachev, V P

    1976-03-01

    The pigment-protein complexes, containing the photosynthetic reaction centers and chlorophyll antenna, were isolated from non-sulfur purple bacteria Rhodospirillum rubrum, by use of cholate. Absorption spectra and quantum yield of photo-oxidation of bacteriochlorophyll P870 of complexes were similar to those of chromatophores. The procedure of reconstitution of proteoliposomes from phospholipids and complexes was proposed. The proteoliposomes incubated with CoQ6 and TMPD upon illumination are generating the transmembrane electric potential difference (plus inside proteoliposomes). The electric potential difference was registered by three independent methods: by transmembrane electrophoresis of penetrating anions PCB-, by direct measurement with using voltmeter in system "proteoliposome--planar membrane" and electrochromic absorption band shifts of bacteriochlorophyll.

  20. [Light-induced oxygen uptake by chromatophores and subchromatophore pigment-protein complexes of Rhodospirillum rubrum].

    PubMed

    Remennikov, V G; Samuilov, V D

    1977-11-01

    Chromatophores of R. rubrum incubated with electron donors, e. g. reduced diaminodurene, TMPD, phenazine methosulphate, cytochrome c or ferrocyanide, are able to catalyze O2 uptake upon illumination. This process is inhibited by o-phenanthroline as well as upon extraction of quinones from chromatophores, but not by antimycin A, rotenone or CN-. The O2 uptake sensitive to the action of o-phenanthroline is also observed in the illuminated subchromatophore P870 reaction center complexes and reaction center plus light-harvesting antenna complexes incubated with electron donors, quinones and detergents. The data obtained are in agreement with a suggestion that the photooxidase activity of chromatophores and subchromatophore pigment-protein complexes is due to the interaction of photoreduced ubiquinone with O2.

  1. Interaction of carbonyl cyanide m-chlorophenylhydrazone with the photosystem II acceptor side.

    PubMed

    Samuilov, V D; Barsky, E L

    1993-04-05

    We show that CCCP, known as an uncoupler of photophosphorylation and an ADRY agent, inhibits FeCy photoreduction and coupled O2 evolution by isolated chloroplasts equally (I50 approximately 2 microM), but is practically without effect on the O2 evolution coupled with SiMo reduction within the 0.2-10 microM concentration range. CCCP has no effect on the nanosecond chlorophyll fluorescence in chloroplasts incubated at low light intensity, but decreases it at high light intensity. The electron transfer from reduced TMPD or duroquinol to methylviologen is resistant to CCCP. The efficiency of the CCCP inhibitory action on the FeCy photoreduction depends on the rate of electron flow, which is controlled by the light intensity. The data obtained show that CCCP is oxidized by the photosystem II donor side and is reduced by QP, competing for electrons with FeCy and the cytochrome blf complex.

  2. Apparent Km of mitochondria for oxygen computed from Vmax measured in permeabilized muscle fibers is lower in water enriched in oxygen by electrolysis than injection.

    PubMed

    Zoll, Joffrey; Bouitbir, Jamal; Sirvent, Pascal; Klein, Alexis; Charton, Antoine; Jimenez, Liliana; Péronnet, François R; Geny, Bernard; Richard, Ruddy

    2015-01-01

    It has been suggested that oxygen (O2) diffusion could be favored in water enriched in O2 by a new electrolytic process because of O2 trapping in water superstructures (clathrates), which could reduce the local pressure/content relationships for O2 and facilitate O2 diffusion along PO2 gradients. Mitochondrial respiration was compared in situ in saponin-skinned fibers isolated from the soleus muscles of Wistar rats, in solution enriched in O2 by injection or the electrolytic process 1) at an O2 concentration decreasing from 240 µmol/L to 10 µmol/L (132 mmHg to 5 mmHg), with glutamate-malate or N, N, N', N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD)-ascorbate (with antimycin A) as substrates; and 2) at increasing adenosine diphosphate (ADP) concentration with glutamate-malate as substrate. As expected, maximal respiration decreased with O2 concentration and, when compared to glutamate-malate, the apparent Km O2 of mitochondria for O2 was significantly lower with TMPD-ascorbate with both waters. However, when compared to the water enriched in O2 by injection, the Km O2 was significantly lower with both electron donors in water enriched in O2 by electrolysis. This was not associated with any increase in the sensitivity of mitochondria to ADP; no significant difference was observed for the Km ADP between the two waters. In this experiment, a higher affinity of the mitochondria for O2 was observed in water enriched in O2 by electrolysis than by injection. This observation is consistent with the hypothesis that O2 diffusion can be facilitated in water enriched in O2 by the electrolytic process.

  3. Isoelectric focusing and crossed immunoelectrophoresis of heme proteins in the Escherichia coli cytoplasmic membrane.

    PubMed Central

    Kranz, R G; Gennis, R B

    1982-01-01

    Isoelectric focusing (IEF), agarose electrophoresis, and crossed immunoelectrophoresis (CIE) were used to resolve the heme-containing proteins of the Escherichia coli cytoplasmic membrane after solubilization by Triton X-100. Two bands in IEF stained for heme with pI values of 4.7 and 5.3. One of the bands, with an isoelectric point of pH 5.3, was present only when the cells were grown to late log or stationary phase and possessed N,N,N,'N'-tetramethyl-p-phenylene-diamine (TMPD) oxidase activity. The pI 4.7 band was present in cells harvested in both mid-log and stationary phases. Agarose electrophoresis, using larger samples, revealed the same two components apparent by IEF, and, in addition, a third component. The heme-containing fractions were extracted after agarose electrophoresis and subjected to further study. The component which was present in cells grown to stationary phase contained hemes b, a1, and d. The other two fractions contained only b heme. One of these corresponded to the component with pI 4.7 in IEF and had catalase activity. Antisera were raised against Triton X-100-solubilized cytoplasmic membranes and against the focused TMPD oxidase complex. With these anti-sera, CIE in the presence of Triton X-100 revealed four precipitin complexes containing heme. Three of these corresponded to the components identified by IEF and agarose electrophoresis. We demonstrate that the combined use of IEF and CIE is valuable for analysis of membrane proteins. In particular, this work represents a substantial initial step toward a structural elucidation of the E. coli aerobic respiratory chain. Images PMID:6277868

  4. Stimulation of Menaquinone-Dependent Electron Transfer in the Respiratory Chain of Bacillus subtilis by Membrane Energization

    PubMed Central

    Azarkina, N.; Konstantinov, A. A.

    2002-01-01

    At a pH of ≤7, respiration of Bacillus subtilis cells on endogenous substrates shut down almost completely upon addition of an uncoupler (carbonyl cyanide m-chlorophenylhydrazone [CCCP]) and a K+-ionophore (valinomycin). The same effect was observed with cell spheroplasts lacking the cell wall. The concentration of CCCP required for 50% inhibition of the endogenous respiration in the presence of K+-valinomycin was below 100 nM. Either CCCP or valinomycin alone was much less efficient than the combination of the two. The inhibitory effect was easily reversible and depended specifically on the H+ and K+ concentrations in the medium. Similar inhibition was observed with respect to the reduction of the artificial electron acceptors 2,6-dichlorophenolindophenol (DCPIP) and N,N,N′,N′-tetramethyl-p-phenylenediamine cation (TMPD+), which intercept reducing equivalents at the level of menaquinol. Oxidation of the reduced DCPIP or TMPD in the bacterial cells was not sensitive to uncoupling. The same loss of the electron transfer activities as induced by the uncoupling was observed upon disruption of the cells during isolation of the membranes; the residual activities were not further inhibited by the uncoupler and ionophores. We conclude that the menaquinone-dependent electron transfer in the B. subtilis respiratory chain is facilitated, thermodynamically or kinetically, by membrane energization. A requirement for an energized state of the membrane is not a specific feature of succinate oxidation, as proposed in the literature, since it was also observed in a mutant of B. subtilis lacking succinate:quinone reductase as well as for substrates other than succinate. Possible mechanisms of the energy-dependent regulation of menaquinone-dependent respiration in B. subtilis are discussed. PMID:12218020

  5. Isoelectric focusing and crossed immunoelectrophoresis of heme proteins in the Escherichia coli cytoplasmic membrane

    SciTech Connect

    Kranz, R.G.; Gennis, R.B.

    1982-04-01

    Isoelectric focusing (IEF), agarose electrophoresis, and crossed immunoelectrophoresis (CIE) were used to resolve the heme-containing proteins of the Escherichia coli cytoplasmic membrane after solubilization by Triton X-100. Two bands in IEF stained for heme with pI values of 4.7 and 5.3. One of the bands, with an isoelectric point of pH 5.3, was present only when the cells were grown to late log or stationary phase and possessed N,N,N,'N'-tetramethyl-p-phenylenediamine (TMPD) oxidase activity. The pI 4.7 band was present in cells harvested in both mid-log and stationary phases. Agarose electrophoresis, using larger samples, revealed the same two components apparent by IEF, and, in addition, a third component. The heme-containing fractions were extracted after agarose electrophoresis and subjected to further study. The component which was present in cells grown to stationary phase contained hemes b, a/sub 1/, and d. The other two fractions contained only b heme. One of these corresponded to the component with pI 4.7 in IEF and had catalase activity. Antisera were raised against Triton X-100-solubilized cytoplasmic membranes and against the focused TMPD oxidase complex. With these anti-sera, CIE in the presence of Triton X-100 revealed four precipitin complexes containing heme. Three of these corresponded to the components identified by IEF and agarose electrophoresis. We demonstrate that the combined use of IEF and CIE is valuable for analysis of membrane proteins. In particular, this work represents a substantial initial step toward a structural elucidation of the E. coli aerobic respiratory chain.

  6. The aerobic electron transport system of Eikenella corrodens.

    PubMed

    Jaramillo, Rubén D; Barraza, Beatriz C; Polo, Alma; Sará, Martín; Contreras, Martha; Escamilla, J Edgardo

    2002-10-01

    The respiratory system of the fastidious beta-proteobacterium Eikenella corrodens grown with limited oxygen was studied. Membranes showed the highest oxidase activity with ascorbate plus N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) or succinate and the lowest activity with NADH and formate. The presence of a bc1-type complex was suggested by the inhibition exerted by 2-heptyl-4-hydroxyquinoline-N-oxide (HOQNO), myxothiazol, and antimycin A on respiration with succinate and by the effect of the latter two inhibitors on the succinate-reduced difference spectra. Respiration with succinate or ascorbate-TMPD was abolished by low KCN concentrations, suggesting the presence of a KCN-sensitive terminal oxidase. Cytochromes b and c were spectroscopically detected after reduction with physiological or artificial electron donors, whereas type a and d cytochromes were not detected. The CO difference spectrum of membranes reduced by dithionite and its photodissociation spectrum (77 K) suggested the presence of a single CO compound that had the spectral features of a cytochrome o-like pigment. High-pressure liquid chromatography analysis of membrane haems confirmed the presence of haem B; in contrast, haems A and O were not detected. Peroxidase staining of membrane type c cytochromes using SDS-PAGE revealed the presence of five bands with apparent molecular masses of 44, 33, 30, 26, and 14 kDa. Based on our results, a tentative scheme of the respiratory chain in E. corrodens, comprising (i) dehydrogenases for succinate, NADH, and formate, (ii) a ubiquinone, (iii) a cytochrome bc1, and (iv) a type-cbb' cytochrome c oxidase, is proposed.

  7. Cyanide-resistant respiration in Taenia crassiceps metacestode (cysticerci) is explained by the H2O2-producing side-reaction of respiratory complex I with O2.

    PubMed

    del Arenal, I Patricia; Rubio, M Esther; Ramírez, Jorge; Rendón, Juan L; Escamilla, J Edgardo

    2005-09-01

    The nature of the cyanide-resistant respiration of Taenia crassiceps metacestode was studied. Mitochondrial respiration with NADH as substrate was partially inhibited by rotenone, cyanide and antimycin in decreasing order of effectiveness. In contrast, respiration with succinate or ascorbate plus N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was more sensitive to antimycin and cyanide. The saturation kinetics for O2 with NADH as substrate showed two components, which exhibited different oxygen affinities. The high-O2-affinity system (Km app=1.5 microM) was abolished by low cyanide concentration; it corresponded to cytochrome aa3. The low-O2-affinity system (Km app=120 microM) was resistant to cyanide. Similar O2 saturation kinetics, using succinate or ascorbate-TMPD as electron donor, showed only the high-O2-affinity cyanide-sensitive component. Horse cytochrome c increased 2-3 times the rate of electron flow across the cyanide-sensitive pathway and the contribution of the cyanide-resistant route became negligible. Mitochondrial NADH respiration produced significant amounts of H2O2 (at least 10% of the total O2 uptake). Bovine catalase and horse heart cytochrome c prevented the production and/or accumulation of H2O2. Production of H2O2 by endogenous respiration was detected in whole cysticerci using rhodamine as fluorescent sensor. Thus, the CN-resistant and low-O2-affinity respiration results mainly from a spurious reaction of the respiratory complex I with O2, producing H2O2. The meaning of this reaction in the microaerobic habitat of the parasite is discussed.

  8. In Vitro Evaluation of the Biocompatibility of Newly Synthesized Bis-Quaternary Ammonium Compounds with Spacer Structures Derived from Pentaerythritol or Hydroquinone.

    PubMed

    Yamamoto, Masashi; Takami, Takashi; Matsumura, Reiko; Dorofeev, Alexander; Hirata, Yoshihiko; Nagamune, Hideaki

    2016-01-01

     With the object of developing new biocides milder for human use than the current antiseptics, we synthesized a series of bis-quaternary ammonium compounds (bis-QACs). The antimicrobial activity of the newly synthesized bis-QACs and common biocides used as antiseptics was compared by examining minimum inhibitory concentrations and minimum bactericidal concentrations (MBCs). Moreover, the cytotoxicity of these compounds against human cells was determined to calculate the biocompatibility index (BI) of these compounds. BI was the ratio of the concentration of a biocide giving a 50% lethal effect on normal human epidermal keratinocytes to its MBC against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The commonly used antiseptics tested were benzalkonium chloride (BAC), octenidine dihydrochloride (OCT), chlorhexidine digluconate (CHG) and polyhexamethylene biguanide (PHMB). In comparison with these antiseptics, it was shown that some of new bis-QACs exhibited a wider and more potent antimicrobial spectrum than OCT. The cytotoxicity of these bis-QACs was equal or lower compared to that of the quaternary ammonium compounds (BAC and OCT), although these bis-QACs showed higher toxicity than the biguanide-based compounds (CHG and PHMB). Finally, the comparison of BIs revealed that new bis-QACs such as N-dodecyl {4,4'-(2,4,8,10-tetraoxaspiro[5.5]undecan-3,9-diyl) }dipyridinium dibromide (4TOSU-12), 3,3'-[1,4-Phenylenebis (oxy)]bis (1-dodecylpyridinium) dibromide (3PHBO-12) and 3-(3-Hydroxy-2-(hydroxymethyl)-2-{[(1-dodecylpyridinium-3-yl) oxy]methyl}propoxy)-1-dodecylpyridinium dibromide (3HHDMP-12) had equal or greater biocompatibility than the commonly used biocides tested. Thus, these results strongly suggested that 4TOSU-12, 3PHBO-12 and 3HHDMP-12 could be useful as antiseptics for topical application to the skin.

  9. Regio- and stereoselective isomerization of hexabromocyclododecanes (HBCDs): kinetics and mechanism of gamma- to alpha-HBCD isomerization.

    PubMed

    Heeb, Norbert V; Schweizer, W Bernd; Mattrel, Peter; Haag, Regula; Gerecke, Andreas C; Schmid, Peter; Zennegg, Markus; Vonmont, Heinz

    2008-11-01

    Hexabromocyclododecanes (HBCDs) are high production volume chemicals (>20000 ty(-1)) used as flame retardants for plastics and textiles. Lately, we reported on the stereoselective isomerization of beta-HBCDs. Herein we present insights into the mechanism and kinetics of (+)gamma- to (+)alpha- and of (-)gamma- to (-)alpha-HBCD isomerization. Only two of the six bromine atoms migrated, indicating that rearrangements of gamma- to alpha-HBCDs are regio- and stereoselective as well. The apparent first-order isomerization rate constants increased from 0.0013 to 0.0031 to 0.0070 min(-1) at 120, 130, and 140 degrees C, respectively, corresponding to half-lives of 540, 230, and 99 min. Thus, a thermal treatment of materials containing gamma-HBCDs at temperatures >100 degrees C may induce the formation of alpha-HBCDs and, hence, may alter the diastereomeric ratio of a HBCD mixture. The inversion of vicinal dibromides in like-configurations (RR/SS) prevailed, whereas unlike-configurations (RS/SR) were not affected. An intramolecular, stereoselective migration of neighboring bromine atoms via a four-center transition state would explain the observed stereoisomer pattern and first-order kinetics. Despite the fact that vicinal dibromides in HBCDs prefer synclinal (gauche) conformations, antiperiplanar (staggered) conformations are assumed to facilitate concerted 1.2-shifts of both bromine atoms. A conformation analysis revealed that under kinetic control, only those bromine atoms in the more flexible part of the molecules are migrating, whereas those in the conserved triple-turn motive were not affected. Thus, this structural motive, common to all alpha-, beta-, and gamma-HBCDs, is more rigid and less reactive than the flexible part, containing the reacting dibromides in like-configurations.

  10. In vitro and in vivo evaluation of pyridinium oximes: mode of interaction with acetylcholinesterase, effect on tabun- and soman-poisoned mice and their cytotoxicity.

    PubMed

    Calić, Maja; Vrdoljak, Ana Lucić; Radić, Bozica; Jelić, Dubravko; Jun, Daniel; Kuca, Kamil; Kovarik, Zrinka

    2006-02-15

    The increased concern about terrorist use of nerve agents prompted us to search for new more effective oximes against tabun and soman poisoning. We investigated the interactions of five bispyridinium oximes: K027 [1-(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide], K048 [1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium) butane dibromide], K033 [1,4-bis(2-hydroxyiminomethylpyridinium) butane dibromide], TMB-4 [1,3-bis(4-hydroxyiminomethylpyridinium) propane dibromide] and HI-6 [(1-(2-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium)-2-oxapropane dichloride)] with human erythrocyte acetylcholinesterase (AChE; E.C. 3.1.1.7) and their effects on tabun- and soman-poisoned mice. All the oximes reversibly inhibited AChE, and the enzyme-oxime dissociation constants were between 17 and 180 microM. Tabun-inhibited AChE was completely reactivated by TMB-4, K027 and K048, with the overall reactivation rate constants of 306, 376 and 673 min(-1)M(-1), respectively. The reactivation of tabun-inhibited AChE by K033 reached 50% after 24h, while HI-6 failed to reactivate any AChE at all. Soman-inhibited AChE was resistant to reactivation by 1mM oximes. All studied oximes protected AChE from phosphorylation with both soman and tabun. In vivo experiments showed that the studied oximes were relatively toxic to mice; K033 was the most toxic (LD50=33.4 mg/kg), while K027 was the least toxic (LD50=672.8 mg/kg). The best antidotal efficacy was obtained with K048, K027 and TMB-4 for tabun poisoning, and HI-6 for soman poisoning. Moreover, all tested oximes showed no cytotoxic effect on several cell lines in concentrations up to 0.8mM. The potency of the oximes K048 and K027 to protect mice from five-fold LD50 of tabun and their low toxicity make these compounds leading in the therapy of tabun poisoning. The combination of HI-6 and atropine is the therapy of choice for soman poisoning.

  11. Kinetics of Mediated Electron Transfer Between Viologen Groups in a Self-Assembled Monolayer and Metal Complexes in Solution

    DTIC Science & Technology

    1993-05-12

    was prepared in a similar manner to 1V1OSH. Bis [N-(n-decyl)-N’-(10-mercaptodecyl)-4,4’-bypridinium] disulfide dibromide (0OV10S-) 2 was prepared as...previously reported (5). Bis [N-(cholesteryl)-N’-(5-mercaptopentyl)-4,4’bipyridium] disulfide tosylate iodide (ChoV5S-) 2 Cholesteryl p-toluene...and excess Proton Sponge which was extracted by washing with 1% HCL 3 times. Bis [N-(n-lH,1H,2H,2H-perfluorododecyl)-N’-(5-mercaptopentyl)-4, 4

  12. Testimony presented to the Massachusetts Department of Public Health, March 19, 1984, Jamaica Plain, Massachusetts

    SciTech Connect

    Griesemer, R.A.

    1984-03-19

    The testimony relates the witness' experience as Director of the Carcinogenesis Bioassay Program at the National Cancer Institute relating to experiments performed with ethylene dibromide (EDB). NCI conducted carcinogenicity bioassays of EDB in rats and mice by both the oral and inhalation routes of exposure. EDB produced multiple kinds of cancer at multiple body sites, in three strains of rats and two strains of mice, in both sexes, at high incidences, with short latent periods, and by three routes of exposure (oral, inhalation, and skin application). (ACR)

  13. Dissociative excitation of the manganese atom quartet levels by collisions e-MnBr2

    NASA Astrophysics Data System (ADS)

    Smirnov, Yu M.

    2017-04-01

    Dissociative excitation of quartet levels of the manganese atom was studied in collisions of electrons with manganese dibromide molecules. Eighty-two cross-sections for transitions originating at odd levels and eleven cross-sections for transitions originating at even levels have been measured at an incident electron energy of 100 eV. An optical excitation function has been recorded in the electron energy range of 0–100 eV for transitions originating from 3d 64p z 4 F° levels. For the majority of transitions, a comparison of the resulting cross-section values to cross-sections produced by direct excitation is provided.

  14. Irradiation and fumigation effects on flavor, aroma and composition of grapefruit products

    SciTech Connect

    Moshonas, M.G.; Shaw, P.E.

    1982-05-01

    Effects were evaluated on grapefruit treated to meet quarantine restrictions against Caribbean fruit fly infestation. Differences were found in flavor of fresh sections, fresh juice, and aroma of peel oil when obtained from fruit irradiated with x-rays, as compared with products from nonirradiated fruit. Flavor differences were found in all pasteurized juices from fruit irradiated at 50-60 krad. Vitamin C levels were significantly lower in juice from most irradiated fruit. Flavor differences were found in fresh and pasteurized juice from fruit treated with methyl bromide, and in pasteurized juice from fruit treated with ethylene dibromide. Aroma differences were found in peel oil from fruit treated with phosphine.

  15. Occupational exposure to 1,3-dichloropropene (Telone II) in Hawaiian pineapple culture

    SciTech Connect

    Albrecht, W.N.

    1987-09-01

    1,3-dichloropropene (DCP), the primary constituent of Telone II, is a subsoil fumigant that has supplanted 1,2-dibromo-3-chloropropane (DBCP) and ethylene dibromide (EDB) as primary fumigant in Hawaiian pineapple culture. To determine the potential for adverse health effects, an environmental survey was done to assess worker exposures. Exposures were predominantly below 1 ppm, which is the no-effect level determined with experimental animals, and the Threshold Limit Value (TLV) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH).

  16. New Synthetic Approach for the Incorporation of 3,2-Hydroxypyridinone (HOPO) Ligands: Synthesis of Structurally Diverse Poly HOPO Chelators

    PubMed Central

    Arumugam, Jayanthi; Brown, Hayley A.; Jacobs, Hollie K.; Gopalan, Aravamudan S.

    2011-01-01

    The HOPO sulfonamide reagent, 3, was prepared from commercial 2,3-dihydroxypyridine in four steps in good yields. Sulfonamide 3 readily underwent selective alkylation with dibromides in the presence of base or could be coupled to alcohols using Mitsunobu conditions. The utility of this nucleophilic HOPO reagent was demonstrated by the synthesis some tris and tetraHOPO chelators. This approach for tethering HOPO ligands is unique and flexible as shown by the preparation of HOPO/iminocarboxylic acid chelator 17. PMID:21709749

  17. 3,3′-Dimethyl-1,1′-[(1,3-dihy­droxy­propane-2,2-di­yl)dimethyl­idene]diimidazolium bis­(hexa­fluoro­phosphate)

    PubMed Central

    Yuan, Ai-Lin; Wang, Chang-Sheng; Zhuang, Ling-Hua; Wang, Guo-Wei

    2010-01-01

    The title compound, C13H22N4O2 2+·2PF6 −, was prepared by the anion exchange of the dibromide ionic liquid with potassium hexa­fluoro­phosphate. The two imidazole rings are each planar (r.m.s. deviations = 0.0016 and 0.0060 Å) and make a dihedral angle of 45.3 (18)°. Intra­molecular O—H⋯F hydrogen bonds occur. Inter­molecular C—H⋯F, O—H⋯O and C—H⋯O hydrogen bonds stabilize the crystal structure. PMID:21589562

  18. SERDP and ESTCP Workshop on Long Term Management of Contaminated Groundwater Sites

    DTIC Science & Technology

    2013-11-01

    attenuation EACO Enhanced Attenuation: Chlorinated Organics EDB ethylene dibromide EI/EC Emerging Issues and Emerging Contaminants ESTCP Environmental...Plumes of Chlorinated Ethylenes Frank Schwartz (The Ohio State University) 1685-09 Coupled Diffusion & Reaction Processes in Rock Matrices...Potential Impact of Changes in the Toxicity and Regulatory Standards of  Chlorinated  Solvents on Long Term Site Management, Remediation Efficiency and Cost

  19. Inhibition of Choline Transport by Redox-active Cholinomimetic Bis-catechol Reagents

    PubMed Central

    Cai, Shuang; Mukherjee, Jhindan; Viranga Tillekeratne, L. M.; Hudson, Richard A.; Kirchhoff, Jon R.

    2007-01-01

    Both N,N′-(2,3-dihydroxybenzyl)-N,N,N′,N′-tetramethyl-1,6-hexanediamine dibromide (DTH, 6) and N,N′-(2,3-dihydroxybenzyl)-N,N,N′,N′-tetramethyl-1,10-decanediamine dibromide (DTD, 7), which are symmetrical bis-catechol substituted hexamethonium and decamethonium analogues, respectively, were found to inhibit high affinity choline transport in mouse brain synaptosomes. Inhibitory properties were evaluated using an extraordinarily sensitive capillary electrophoresis method employing electrochemical detection at an enzyme-modified microelectrode. Dose-response curves were generated for each inhibitor and IC50 values were determined to be 76 μM for 6 and 21 μM for 7. Lineweaver-Burk analysis revealed that both molecules inhibit high affinity choline uptake by a mixed inhibition mechanism. The KI values for 6 and 7 were determined to be 73 ± 1 and 31 ± 2 μM, respectively. The inhibition properties were further compared to a series of mono-catechol analogues, 3-[(trimethylammonio)methyl]catechol (1), N,N-dimethylepinephrine (4) and 6-hydroxy-N,N-dimethylepinephrine (5), as well as the well-characterized hemicholinium inhibitors, hemicholinium-15 (HC-15, 8) and hemicholinum-3 (HC-3, 9). PMID:17827016

  20. The influence of antidotal treatment of low-level tabun exposure on cognitive functions in rats using a water maze.

    PubMed

    Kassa, J; Kunesova, G

    2006-01-01

    In this study, the influence of antidotal treatment of tabun poisoning on cognitive function, in the case of low-level tabun exposure, was studied. The impairment of cognitive function was evaluated by the measurement of spatial learning and memory in rats poisoned with a sublethal dose of tabun and treated with atropine alone or in combination with newly developed oximes {K027 [1-(4-hydroxyiminomethyl- pyridinium)-3-(4-carbamoylpyridinium) propane dibromide] and K048 [1-(4-hydroxyimino- methylpyridinium)-3-(4-carbamoylpyridinium) butane dibromide]} or currently available oxime (trimedoxime), using the Morris water maze. While atropine alone caused an impairment of studied cognitive functions, the addition of an oxime to atropine contributes to the improvement of cognitive performance of treated tabun-poisoned rats regardless of the type of oxime. The differences in the ameliorative effects of oximes on atropine-induced mnemonic deficits were not significant. Therefore, each low-level nerve agent exposure should be treated by complex antidotal treatment consisting of anticholinergic drug and oxime.

  1. Agents related to a potent activator of the acetylcholine receptor of Electrophorus electricus.

    PubMed

    Wassermann, N H; Erlanger, B F

    1981-09-01

    The synthesis of a number of compounds related to trans-3,3'-bis[alpha-(trimethylammonium)methyl]azobenzene dibromide (trans-3,3'-BisQ) (1) is described. Among the compounds are: [14C]-trans-3,3'-BisQ (1) diiodide, cis-3,3'-BisQ (2) dibromide, the trans-2,2' (7) and 4,4' (11) isomers of BisQ, 2,2', (12), 3,3' (13) and 4,4' (14) isomers of bis-benzyldimethylammonium analogues, and related compounds in which the azo bridge between the two aromatic rings is replaced by diketo and amide bridges. Of them all trans-3,3'-BisQ (1) was the most active cholinergic compound in the electroplax system of Electrophorus electricus; the pure cis isomer (2) was without activity. Intermediate activities were found for some of the other compounds and others were inhibitors. The relationship of the structure of these agents to a proposed conformation and topography of the binding site of the acetylcholine receptor (AChR) is discussed.

  2. Comprehensive study of tartrazine/cationic surfactant interaction.

    PubMed

    Shahir, Afshin Asadzadeh; Javadian, Soheila; Razavizadeh, Bi Bi Marzieh; Gharibi, Hussein

    2011-12-15

    Interaction of a food dye, tartrazine, with some cationic conventional and gemini surfactants, tetradecyltrimethylammonium bromide (TTAB), N,N'-ditetradecyl-N,N,N',N'-tetramethyl-N,N'-butanediyl-diammonium dibromide (14,4,14), and N,N'-didodecyl-N,N,N',N'-tetramethyl-N,N'-butanediyl-diammonium dibromide (12,4,12), were first investigated comprehensively employing conductometry, tensiometry, and UV-visible spectroscopy. Tartrazine was found to behave in the same manner as aromatic counterions. The formation of ion pairs reflected as a considerable increase of the surfactant efficiency in tensiometry plots and their stoichiometry were determined by Job's method of continuous variations. For the tartrazine/TTAB system, nonionic DS(3), ionic DS(2-), and/or DS(2)(-) ion pairs, their small premicelles, and tartrazine-rich micelles were constituted as well as dye-containing TTAB-rich micelles. Insoluble J-aggregates of DS(-) ion pairs and cylindrical surfactant-rich micelles were also formed in tartrazine/gemini surfactant systems and recognized by transmission electron microscopy. The zeta potential and the size of the aggregates were determined using dynamic light scattering and confirmed the suggested models for the processes happening in each system. Cyclic voltammetry was applied successfully to track all of these species using tartrazine's own reduction peak current for the first time.

  3. Enhanced metabolism of halogenated hydrocarbons in transgenic plants containing mammalian cytochrome P450 2E1

    PubMed Central

    Doty, Sharon Lafferty; Shang, Tanya Q.; Wilson, Angela M.; Tangen, Jeff; Westergreen, Aram D.; Newman, Lee A.; Strand, Stuart E.; Gordon, Milton P.

    2000-01-01

    Chlorinated solvents, especially trichloroethylene (TCE), are the most widespread groundwater contaminants in the United States. Existing methods of pumping and treating are expensive and laborious. Phytoremediation, the use of plants for remediation of soil and groundwater pollution, is less expensive and has low maintenance; however, it requires large land areas and there are a limited number of suitable plants that are known to combine adaptation to a particular environment with efficient metabolism of the contaminant. In this work, we have engineered plants with a profound increase in metabolism of the most common contaminant, TCE, by introducing the mammalian cytochrome P450 2E1. This enzyme oxidizes a wide range of important pollutants, including TCE, ethylene dibromide, carbon tetrachloride, chloroform, and vinyl chloride. The transgenic plants had a dramatic enhancement in metabolism of TCE of up to 640-fold as compared with null vector control plants. The transgenic plants also showed an increased uptake and debromination of ethylene dibromide. Therefore, transgenic plants with this enzyme could be used for more efficient remediation of many sites contaminated with halogenated hydrocarbons. PMID:10841534

  4. Enhanced metabolism of halogenated hydrocarbons in transgenic plants containing mammalian cytochrome P450 2E1.

    PubMed

    Doty, S L; Shang, T Q; Wilson, A M; Tangen, J; Westergreen, A D; Newman, L A; Strand, S E; Gordon, M P

    2000-06-06

    Chlorinated solvents, especially trichloroethylene (TCE), are the most widespread groundwater contaminants in the United States. Existing methods of pumping and treating are expensive and laborious. Phytoremediation, the use of plants for remediation of soil and groundwater pollution, is less expensive and has low maintenance; however, it requires large land areas and there are a limited number of suitable plants that are known to combine adaptation to a particular environment with efficient metabolism of the contaminant. In this work, we have engineered plants with a profound increase in metabolism of the most common contaminant, TCE, by introducing the mammalian cytochrome P450 2E1. This enzyme oxidizes a wide range of important pollutants, including TCE, ethylene dibromide, carbon tetrachloride, chloroform, and vinyl chloride. The transgenic plants had a dramatic enhancement in metabolism of TCE of up to 640-fold as compared with null vector control plants. The transgenic plants also showed an increased uptake and debromination of ethylene dibromide. Therefore, transgenic plants with this enzyme could be used for more efficient remediation of many sites contaminated with halogenated hydrocarbons.

  5. Near-field air concentrations of pesticides in potato agriculture in Prince Edward Island.

    PubMed

    Garron, Christine A; Davis, Kimberly C; Ernst, William R

    2009-06-01

    Pesticides in air have become of increasing concern in recent years. This study examined downwind air concentrations of carbofuran, methamidophos, mancozeb and diquat dibromide resulting from spray drift within 24 h of application, within 100 m of potato fields. Concentrations ranged from less than 0.05 microg m(-3) in prespray samples to 6.37 microg m(-3) for methamidophos at 3 h post-spray. For most applications, air concentrations decreased with distance from the field and with time after application. Methamidophos concentrations in the air downwind continued to increase up to 3 h after spray. Air concentrations during spray were positively correlated with application rate (r = 0.904), and air concentrations at 1 h and 3 h post-spray were positively correlated with vapour pressure (r = 1.000 and r = 0.999 respectively). Carbofuran, methamidophos and diquat dibromide concentrations during spray were above some Canadian and international health protection guidelines. Although pesticide air concentrations measured in this study are generally consistent with other studies, maximum concentrations are greater than those that have been measured elsewhere, and some are above published air quality guidelines. An evaluation of the degree of risk posed by these and other pest control products to human and wildlife receptors is recommended.

  6. Methods for strand-specific DNA detection with cationic conjugated polymers suitable for incorporation into DNA chips and microarrays.

    PubMed

    Liu, Bin; Bazan, Guillermo C

    2005-01-18

    A strand-specific DNA sensory method is described based on surface-bound peptide nucleic acids and water-soluble cationic conjugated polymers. The main transduction mechanism operates by taking advantage of the net increase in negative charge at the peptide nucleic acid surface that occurs upon single-stranded DNA hybridization. Electrostatic forces cause the oppositely charged cationic conjugated polymer to bind selectively to the "complementary" surfaces. This approach circumvents the current need to label the probe or target strands. The polymer used in these assays is poly[9,9'-bis(6''-N,N,N-trimethylammonium)hexyl)fluorene-co-alt-4,7-(2,1,3-benzothiadiazole) dibromide], which was specifically designed and synthesized to be compatible with excitation sources used in commonly used DNA microarray readers. Furthermore, the utility of poly[9,9'-bis(6''-N,N,N-trimethylammonium)-hexyl)fluorene-co-alt-4,7-(2,1,3-benzothiadiazole) dibromide] has been demonstrated in homogenous and solid-state assays that involve fluorescence resonance energy transfer to a reporter dye (Cy5) and that can benefit from the light harvesting properties observed in water-soluble conjugated polymers.

  7. Reconstitution of biological molecular generators of electric current. Bacteriochlorophyll and plant chlorophyll complexes.

    PubMed

    Barsky, E L; Dancshazy, Z; Drachey, L A; Il'ina, M D; Jasaitis, A A; Kondrashin, A A; Samuilov, V D; Skulachev, V P

    1976-11-25

    1. Electric generation by bacteriochlorophyll reaction center complexes from Rhodospirillum rubrum and by photosystem I complexes from pea chloroplasts has been studied. 2. The methods for the proteoliposome reconstitution from azolectin and bacteriochlorophyll- or plant chlorophyll-containing protein complexes have been elaborated. Light-dependent electric responses of the proteoliposomes were detected using (a) phenyldicarbaundecarborane anion (PCB-) probe and (b) direct measurement by a voltmeter in the proteoliposome-planar phospholipid membrane system. 3. Both PCB- and direct measurements demonstrated that bacteriochlorophyll proteoliposomes are competent in light-dependent electric generation (plus outside proteoliposomes). The photoelectric effect was shown to increase on addition of tetramethyl-p-phenylenediamine (TMPD), CoQ6, and vitamin K3, and to decrease on addition of ferricyanide, o-phenanthroline and a protonophorous uncoupler. Estimation of the photoelectromotive force of the bacteriochlorophyll proteoliposome-planar membrane system gave a value of about 0.2 V. The action spectrum of the photoelectric effect was similar to the absorption spectrum of the bacteriochlorophyll complex. 4. Reconstitution of proteoliposomes containing bacteriochlorophyll centers and bacteriorhodopsin resulted in the system generating an electric field whose direction can be changed by varying the spectral composition of the light: the red light, exciting bacteriochlorophyll, induces negative, and the green light, exciting bacteriorhodopsin, induces positive charging of the proteoliposome interior. 5. Association of isolated R. rubrum chromatophores with planar phospholipid membrane was found to give a system demonstrating light-induced electric generation as high as 215 mV in the presence of napthoquinone, TMPD (or phenazine methosulfate, PMS), and ascorbate. Under the same conditions, addition of inorganic pyrophosphate or ATP results in formation of an electric field of

  8. Fish embryo toxicity test: identification of compounds with weak toxicity and analysis of behavioral effects to improve prediction of acute toxicity for neurotoxic compounds.

    PubMed

    Klüver, Nils; König, Maria; Ortmann, Julia; Massei, Riccardo; Paschke, Albrecht; Kühne, Ralph; Scholz, Stefan

    2015-06-02

    The fish embryo toxicity test has been proposed as an alternative for the acute fish toxicity test, but concerns have been raised for its predictivity given that a few compounds have been shown to exhibit a weak acute toxicity in the fish embryo. In order to better define the applicability domain and improve the predictive capacity of the fish embryo test, we performed a systematic analysis of existing fish embryo and acute fish toxicity data. A correlation analysis of a total of 153 compounds identified 28 compounds with a weaker or no toxicity in the fish embryo test. Eleven of these compounds exhibited a neurotoxic mode of action. We selected a subset of eight compounds with weaker or no embryo toxicity (cyanazine, picloram, aldicarb, azinphos-methyl, dieldrin, diquat dibromide, endosulfan, and esfenvalerate) to study toxicokinetics and a neurotoxic mode of action as potential reasons for the deviating fish embryo toxicity. Published fish embryo LC50 values were confirmed by experimental analysis of zebrafish embryo LC50 according to OECD guideline 236. Except for diquat dibromide, internal concentration analysis did not indicate a potential relation of the low sensitivity of fish embryos to a limited uptake of the compounds. Analysis of locomotor activity of diquat dibromide and the neurotoxic compounds in 98 hpf embryos (exposed for 96 h) indicated a specific effect on behavior (embryonic movement) for the neurotoxic compounds. The EC50s of behavior for neurotoxic compounds were close to the acute fish toxicity LC50. Our data provided the first evidence that the applicability domain of the fish embryo test (LC50s determination) may exclude neurotoxic compounds. However, neurotoxic compounds could be identified by changes in embryonic locomotion. Although a quantitative prediction of acute fish toxicity LC50 using behavioral assays in fish embryos may not yet be possible, the identification of neurotoxicity could trigger the conduction of a conventional fish

  9. Influence of inorganic and organic nutrients on aerobic biodegradation and on the adaptation response of subsurface microbial communities

    SciTech Connect

    Swindoll, C.M.; Aelion, C.M.; Pfaender, F.K.

    1988-01-01

    The influence of inorganic and organic amendments on the mineralization of ethylene dibromide, rho-nitrophenol, phenol, and toluene was examined in subsurface soil samples from a pristine aquifer near Lula, Oklahoma. The responses indicate that the metabolic abilities and nutrient requirements of ground water microorganisms vary substantially within an aquifer. In some samples, additions of inorganic nutrients resulted in a more rapid adaptation to the test substrate and a higher rate of metabolism, indicating that metabolism may have been limited by these nutrients. In other samples from the same aquifer layer, inorganic amendments had little or no influence on mineralization. In general, the addition of multiple inorganic nutrients resulted in a greater enhancement of degradation than did the addition of single substances. Additions of alternate carbon sources, such as glucose or amino acids, inhibited the mineralization of the xenobiotic substrates. This inhibition appears to be the result of the preferential utilization of the more easily degradable carbon amendments.

  10. Reactivation of human brain homogenate cholinesterases inhibited by Tabun using newly developed oximes K117 and K127.

    PubMed

    Kuca, Kamil; Cabal, Jiri; Jung, Yung Sik; Musilek, Kamil; Soukup, Ondrej; Jun, Daniel; Pohanka, Miroslav; Musilova, Lucie; Karasová, Jana; Novotný, Ladislav; Hrabinova, Martina

    2009-09-01

    Newly developed acetylcholinesterase reactivators K117 [1,5-bis(4-hydroxyiminomethylpyridinium)-3-oxapentane dichloride] and K127 [(1-(4-hydroxyiminomethylpyridinium)-5-(4-carbamoylpyridinium)-3-oxapentane dibromide)] were tested for their potency to reactivate tabun-inhibited human brain cholinesterases. Pralidoxime and trimedoxime were chosen as standard reference reactivators. Human tissue was used, as that was closer on the real treatment of human beings. As a result, oxime K127 was found as the best tested reactivator according to the constant k(r), characterizing the overall reactivation process. On the contrary, the maximal reactivation ability expressed as percentage of reactivation was the best for trimedoxime. This differences were caused as a result of using the enzyme from different species. Due to this, experiments on human tissue should be conducted after in vitro and in vivo tests on animals to eliminate such important failures of promising oximes.

  11. Monooxime reactivators of acetylcholinesterase with (E)-but-2-ene linker: preparation and reactivation of tabun- and paraoxon-inhibited acetylcholinesterase.

    PubMed

    Musilek, Kamil; Holas, Ondrej; Jun, Daniel; Dohnal, Vlastimil; Gunn-Moore, Frank; Opletalova, Veronika; Dolezal, Martin; Kuca, Kamil

    2007-11-01

    Acetylcholinesterase reactivators are crucial antidotes for the treatment of organophosphate intoxication. Fifteen new monooxime reactivators of acetylcholinesterase with a (E)-but-2-ene linker were developed in an effort to extend the properties of K-oxime (E)-1-(4-carbamoylpyridinium)-4-(4-hydroxyiminomethylpyridinium)-but-2-ene dibromide (K203). The known reactivators (pralidoxime, HI-6, obidoxime, K075, K203) and the new compounds were tested in vitro on a model of tabun- and paraoxon-inhibited AChE. Monooxime reactivators were not able to exceed the best known compounds for tabun poisoning, but some of them did show reactivation comparable with known compounds for paraoxon poisoning. However, extensive differences were found by a SAR study for various substitutions on the non-oxime part of the reactivator molecule.

  12. Postharvest-applied agrochemicals and their residues in fresh fruits and vegetables.

    PubMed

    Papadopoulou-Mourkidou, E

    1991-01-01

    Many agrochemicals are applied postharvest on fruits and vegetables to extend their lives and preserve quality during storage, transport, and marketing. Persistence and distribution of residues on the edible portions of produce have been reported for citrus fruits, pome fruits, stone fruits, mangos, strawberries, bananas, kiwi fruits, avocados, some minor fruit commodities, and bell peppers and tomatoes. Data on the persistance and residues of the fungicides benomyl, biphenyl, sec-butylamine, captan, carbendazim, dicloran, fosetyl-aluminum, guazatine, imazalli, iprodione, metalaxyl, o-phenylphenol, prochloraz, thiabendazole, thiophanate-methyl, triadimeton, and vinclozolin, the fumigants ethylene dibromide, methyl bromide, and sulfur dioxide, the insecticides dimethoate and fenthion, the antiscald compounds diphenylamine and ethoxyquin, and the growth regulators 2,4-D and daminozide are presented and discussed.

  13. Troubled waters: a Florida nightmare

    SciTech Connect

    Cooper, W.

    1984-12-01

    Results of studies of pollution of groundwater in Florida are reported. Vast amounts of the underground water were found to be polluted with ethylene dibromide (EDB) used by Florida farmers since the 1950s as an insecticide. Pollution levels of water in the middle of the citrus belt were found to be as high as 775 ppB when 0.02 ppB has been set by the Florida Agriculture Department as the level for concern. EDB can be removed using activated charcoal filters, or new wells can tap aquifers separated from contaminated ones by beds of impermeable clay. Evidences of contamination of water in specific sites by cresote, sulfuric acid, and heavy metals such as lead and arsenic are mentioned.

  14. Enhancement of Shelf Life of Button Mushroom, Agaricus bisporus (Higher Basidiomycetes) by Fumigant Application of Lippia alba Essential Oil.

    PubMed

    Vishwakarma, Pratima; Pandey, Abhay K; Mishra, Priyanka; Singh, Pooja; Tripathi, N N

    2015-01-01

    Eleven essential oils isolated from higher plant species were assessed against the four isolates of Verticillium fungicola found on fruiting bodies of Agaricus bisporus. Eucalyptus citriodora and Lippia alba oils were more efficacious and completely inhibited the mycelial growth of fungal isolates. L. alba oil was fungistatic and fungicidal at 10- and 20-µL concentrations against all of the isolates, respectively, and was more potent than E. citriodora oil as well as some prevalent synthetic fungicides such as benomyl, ethylene dibromide, and phosphine. Eighty microliters of L. alba oil protected 500 g of fruiting bodies of A. bisporus for up to 7 d from infection of the fungus under in vivo conditions. The findings strengthen the possibility of L. alba oil as a plant-based protectant to enhance the shelf life of A. bisporus fruiting bodies.

  15. Exploratory studies aimed at a synthesis of vinigrol. 4. Probe of possible means for direct connection of the side arms and of ring-contraction alternatives.

    PubMed

    Paquette, Leo A; Liu, Zuosheng; Efremov, Ivan

    2005-01-21

    Attempts have been made to gain access to the vinigrol structural framework by way of three routes. These include reductive transannular cyclization, adaptation of the Ramberg-Backlund rearrangement, and deployment of the lactam-sulfoxide ring contraction protocol. While the first of these options involves direct transannular C-C bond formation, the other two embody the concept of larger ring construction as a prelude to ring contraction. The initial installation of a sulfur atom involves prior thiacyclononane formation, a process believed to be potentially easier to accomplish. However, arrival at 13, 14, or 17 was not achieved. Installation of the heterocyclic ring contained in 31 proved to be equally problematic. Increased disassembly of the molecular structure as featured in dibromide 20 did allow for direct conversion to sulfone 22. This advanced building block proved not be conducive to in situ alpha-chlorination and extrusion of the sulfur atom.

  16. Electron attachment to 14 halogenated alkenes and alkanes, 300-600 K.

    PubMed

    Shuman, Nicholas S; Friedman, Jeffrey F; Miller, Thomas M; Viggiano, A A

    2012-10-28

    Thermal electron attachment to 14 alkenes and alkanes with bromine, fluorine, and iodine substituents has been studied over the temperature range 300-600 K using a flowing-afterglow Langmuir-probe apparatus. Rate coefficients and anion products are reported, most for the first time. Among these were 3 isomers of C(3)F(5)Br and the 2 isomers of C(3)F(7)I. Four dibromide compounds were studied, all of which yield Br(2)(-) product in addition to Br(-) product. The results are analyzed using a statistical kinetic modeling approach, which is able to reproduce both attachment rate coefficients and product branching ratios within experimental uncertainty. The kinetic modeling indicates that factor of 2 differences in attachment rate coefficients to the isomeric species can be explained by subtle variations in the potential surfaces.

  17. Electron attachment to halogenated alkenes and alkanes, 300-600 K

    NASA Astrophysics Data System (ADS)

    Miller, Thomas M.; Friedman, Jeffrey F.; Shuman, Nicholas S.; Viggiano, Albert A.

    2012-10-01

    Rate coefficients (ka) and ion product distributions have been measured for 14 alkenes and alkanes with bromine, fluorine, and iodine substituents over the temperature range T = 300-600 K using a flowing-afterglow Langmuir-probe apparatus (FALP), most for the first time. Among these are 3 isomers of C3F5Br and 2 isomers of C3F7I. Four dibromide compounds yield Br2^- in addition to Br^-. The results follow the expected trends: ka values near the capture limit decrease slightly with T according to Vogt-Wannier theory, while ka increase with T for molecules which have small ka at 300 K. The results are analyzed using a statistical kinetic modeling approach, which is able to reproduce ka values and product branching within experimental uncertainty. The modeling indicates that factor of 2 differences in ka for the isomeric species can be explained by subtle variations in the potential surfaces.

  18. Electron attachment to 14 halogenated alkenes and alkanes, 300-600 K

    NASA Astrophysics Data System (ADS)

    Shuman, Nicholas S.; Friedman, Jeffrey F.; Miller, Thomas M.; Viggiano, A. A.

    2012-10-01

    Thermal electron attachment to 14 alkenes and alkanes with bromine, fluorine, and iodine substituents has been studied over the temperature range 300-600 K using a flowing-afterglow Langmuir-probe apparatus. Rate coefficients and anion products are reported, most for the first time. Among these were 3 isomers of C3F5Br and the 2 isomers of C3F7I. Four dibromide compounds were studied, all of which yield Br2- product in addition to Br- product. The results are analyzed using a statistical kinetic modeling approach, which is able to reproduce both attachment rate coefficients and product branching ratios within experimental uncertainty. The kinetic modeling indicates that factor of 2 differences in attachment rate coefficients to the isomeric species can be explained by subtle variations in the potential surfaces.

  19. Removing EDB with GAC filters

    SciTech Connect

    Narbaitz, R.M.; Baratta, A.; Parsons, F.Z. )

    1994-08-01

    Nearly 1,000 point-of-entry granular activated carbon (GAC) filters are efficiently removing ethylene dibromide (EDB) from contaminated groundwater throughout Florida. This article discusses the design, performance, and operational problems of the filters and assesses the possibility of extending the interval between GAC replacement from the current six months. Few breakthroughs have occurred in these filters, and most were caused by desorption during periods of sharp decreases in well-water EDB concentrations. Because GAC loading data from the literature described the program data very well, they were used in conjunction with the equilibrium column model to predict the performance of the program's filters for different GAC replacement periods. Based on the most conservative estimates, maintenance for 50% of the filters could be extended to every nine months.

  20. Innovative technology for expedited site remediation of extensive surface and subsurface contamination

    SciTech Connect

    Audibert, J.M.E.; Lew, L.R.

    1994-12-31

    Large scale surface and subsurface contamination resulted from numerous releases of feed stock, process streams, waste streams, and final product at a major chemical plant. Soil and groundwater was contaminated by numerous compounds including lead, tetraethyl lead, ethylene dibromide, ethylene dichloride, and toluene. The state administrative order dictated that the site be investigated fully, that remedial alternative be evaluated, and that the site be remediated within a year period. Because of the acute toxicity and extreme volatility of tetraethyl lead and other organic compounds present at the site and the short time frame ordered by the regulators, innovative approaches were needed to carry out the remediation while protecting plant workers, remediation workers, and the public.

  1. NIOSH current intelligence bulletins: summaries

    SciTech Connect

    Not Available

    1988-09-01

    Summaries were offered of the current intelligence bulletins issued from January 20, 1975 to August of 1988. They include information on the following topics: chloroprene, trichloroethylene, ethylene dibromide, chrome pigment, asbestos, hexamethylphosphoric triamide, polychlorinated biphenyls, 4,4'-diaminodiphenylmethane, chloroform, radon daughters, dimethylcarbamoyl chloride, diethylcarbamoyl-chloride, explosive azide hazard, inorganic arsenic, nitrosamines in cutting fluids, metabolic precursors of beta-naphthylamine, 2-nitropropane, acrylonitrile, 2,4-diaminoanisole, tetrachloroethylene, trimellitic anhydride, ethylene thiourea, disulfiram, direct-blue-6, direct-black-38, direct-brown-95, benzidine derived dyes, ethylene dichloride, NIAX catalyst ESN, chloroethanes, vinyl halides, glycidyl ethers, epichlorohydrin, smoking, arsine poisoning, radiofrequency sealers and heaters, formaldehyde, ethylene oxide, silica flour, vibration syndrome, glycol ethers, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,3-butadiene, cadmium, monohalomethanes, dinitrotoluenes, methylene chloride, 4,4'-methylenedianiline, organic solvent neurotoxicity, mechanical power press injuries, and the carcinogenic effects of diesel exhaust.

  2. Self-assembly of conjugated polymer on hybrid nanospheres for cellular imaging applications.

    PubMed

    Xia, Bihua; Wang, Xiaoyu; He, Fang; Cui, Qianling; Li, Lidong

    2012-11-01

    A new kind of hybrid core-shell nanosphere was fabricated by combining the in situ formation of Au nanoparticles and covalent cross-linking of biocompatible carboxymethyl starch dialdehyde (CMSD) and chitosan (CTS). When the fluorescent dye poly[9,9'-bis(6″-(N,N,N-trimethylammonium)-hexyl)fluorene-2,7-ylenevinylene-co-alt-1,4-phenylene dibromide] (PFV) was assembled on the surface of the hybrid nanospheres through electrostatic attraction, these biocompatible hybrid nanospheres exhibited metal-enhanced fluorescence effects. The fluorescence intensity of (CTS-Au)@CMSD/PFV hybrid nanosphere is 1.43 times that of CTS-CMSD/PFV hybrid nanospheres lacking Au nanoparticle. In addition, the (CTS-Au)@CMSD/PFV hybrid nanospheres exhibit excellent biodegradability upon exposure to enzymatic aqueous solution and good biocompatibility when cocultured with HeLa cervical carcinoma cells; these advantages make them attractive for cellular imaging and biological analysis and detection.

  3. Simple synthesis of P(Cbz-alt-TBT) and PCDTBT by combining direct arylation with suzuki polycondensation of heteroaryl chlorides.

    PubMed

    Lombeck, Florian; Matsidik, Rukiya; Komber, Hartmut; Sommer, Michael

    2015-01-01

    Direct arylation (DA) of 2-chlorothiophene and 2-chloro-3-hexylthiophene with 4,7-dibromo-2,1,3-benzothiadiazole is used to synthesize 4,7-bis(5-chloro-2-thienyl)-2,1,3-benzothiadiazole (TBTCl2) and 4,7-bis(5-chloro-4-hexyl-2-thienyl)-2,1,3-benzothiadiazole (DH-TBTCl2) in one step. Suitable conditions of the Suzuki polycondensations (SPC) of TBTCl2 and DH-TBTCl2 with the carbazole comonomer CbzPBE2 are established, furnishing PCDTBT and P(Cbz-alt-TBT) with high molecular weight and yield. Compared with control samples made from the corresponding dibromides, high-temperature NMR and UV-vis spectroscopy indicate similar properties for PCDTBT but an increased content of Cbz-Cbz homocouplings for P(Cbz-alt-TBT).

  4. Ultrasound assisted the preparation of 1-butoxy-4-nitrobenzene under a new multi-site phase-transfer catalyst--kinetic study.

    PubMed

    Harikumar, Kuppuswamy; Rajendran, Venugopal

    2014-01-01

    In the present research work deals with the preparation of 1-butoxy-4-nitrobenzene was successfully carried out by 4-nitrophenol with n-butyl bromide using aqueous potassium carbonate and catalyzed by a new multi-site phase-transfer catalyst (MPTC) viz., N(1),N(4)-diethyl-N(1),N(1),N(4),N(4)-tetraisopropylbutane-1,4-diammonium dibromide, under ultrasonic (40 kHz, 300 W) assisted organic solvent condition. The pseudo first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (40 kHz, 300 W) in a batch reactor, it shows that the overall reaction greatly enhanced with ultrasound irradiation than without ultrasound. The present study provides a method to synthesize nitro aromatic ethers by ultrasound assisted liquid-liquid multi-site phase-transfer catalysis condition. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Gated Channels and Selectivity Tuning of CO2 over N2 Sorption by Post-Synthetic Modification of a UiO-66-Type Metal-Organic Framework.

    PubMed

    Kronast, Alexander; Eckstein, Sebastian; Altenbuchner, Peter T; Hindelang, Konrad; Vagin, Sergei I; Rieger, Bernhard

    2016-08-26

    The highly porous and stable metal-organic framework (MOF) UiO-66 was altered using post-synthetic modifications (PSMs). Prefunctionalization allowed the introduction of carbon double bonds into the framework through a four-step synthesis from 2-bromo-1,4-benzenedicarboxylic acid; the organic linker 2-allyl-1,4-benzenedicarboxylic acid was obtained. The corresponding functionalized MOF (UiO-66-allyl) served as a platform for further PSMs. From UiO-66-allyl, epoxy, dibromide, thioether, diamine, and amino alcohol functionalities were synthesized. The abilities of these compounds to adsorb CO2 and N2 were compared, which revealed the structure-selectivity correlations. All synthesized MOFs showed profound thermal stability together with an increased ability for selective CO2 uptake and molecular gate functionalities at low temperatures.

  6. Total synthesis of SR 121463 A, a highly potent and selective vasopressin v(2) receptor antagonist.

    PubMed

    Venkatesan, H; Davis, M C; Altas, Y; Snyder, J P; Liotta, D C

    2001-06-01

    SR 121463 A, 1, is a promising nonpeptide prototype for potent and selective antagonism of the vasopressin V(2) receptor subtype and, thus, a candidate for control of the clinically debilitating condition of hyponatremia and its associated syndromes. In the present work, we present a novel and stereoselective synthesis that stems from the preparation of three key intermediates: the substituted benzenesulfonyl chloride 2, the N-protected oxindole 3, and protected dibromide 4. The synthesis of 1 has been achieved in good overall yield, each step proceeding in greater than 80% yield. In addition, intermediate 2 and the syn isomer of 1 were prepared with complete control of stereochemistry. The latter reduction appears to proceed by lithium cation mediated chelation control. Molecular mechanics calculations with the MM3* and MMFF force fields underscore geometric and energetic aspects of the reaction.

  7. Total synthesis of lepadiformine alkaloids using N-Boc α-amino nitriles as trianion synthons.

    PubMed

    Perry, Matthew A; Morin, Matthew D; Slafer, Brian W; Rychnovsky, Scott D

    2012-04-06

    Lepadiformine A, B, and C were synthesized in an enantiomerically pure form using a reductive cyclization strategy. N-Boc α-amino nitriles were deprotonated and alkylated with enantiomerically pure dibromides to afford the first ring. The products were manipulated to introduce phosphate leaving groups, and subsequent reductive lithiation followed by intramolecular alkylation formed the second ring with high stereoselectivity. The third ring was formed by intramolecular displacement of a mesylate by the deprotected amine. Lepadiformine A and B contain a hydroxymethyl group adjacent to the amine. This appendage was introduced in a sequence using a Polonovski-Potier reaction as the key step. The synthetic strategy is stereoselective and convergent and demonstrates the utility of N-Boc α-amino nitriles as linchpins for alkaloid synthesis.

  8. Total Synthesis of Lepadiformine Alkaloids using N-Boc α-Amino Nitriles as Trianion Synthonsa

    PubMed Central

    Perry, Matthew A.; Morin, Matthew D.; Slafer, Brian W.

    2012-01-01

    Lepadiformine A, B and C were synthesized in enantiomerically pure form using a reductive cyclization strategy. N-Boc α-amino nitriles were deprotonated and alkylated with enantiomerically pure dibromides to afford the first ring. The products were manipulated to introduce phosphate leaving-groups, and subsequent reductive lithiation followed by intramolecular alkylation formed the second ring with high stereoselectivity. The third ring was formed by intramolecular displacement of a mesylate by the deprotected amine. Lepadiformine A and B contain a hydroxymethyl group adjacent to the amine. This appendage was introduced in a sequence using a Polonovski-Potier reaction as the key step. The synthetic strategy is stereoselective and convergent, and demonstrates the utility of N-Boc α-amino nitriles as linchpins for alkaloid synthesis. PMID:22413935

  9. Pathogenicity of Criconemoides xenoplax to Prune and Plum Rootstocks

    PubMed Central

    Mojtahedi, H.; Lownsbery, B. F.

    1975-01-01

    Elimination of Criconemoides xenoplax from a prune orchard soil by fumigation with ethylene dibromide at the rate of 42 μliter/liter of soil (equivalent to about 13 gal/acre) improved the growth of Myrobalan plum, Addition of this nematode to Myrobalan seedlings or young 'Marianna 2624' plants propagated from cuttings resulted in destruction of cortical root tissue, darkening of roots, alteration of water stress, lowering of nutrient levels in leaves, and reduction in plant weight. C. xenoplax increased on all nine Prunus cerasifera varieties and hybrids tested, including those used commonly as rootstocks for prunes and plums. Rhizoctonia solani isolated from Myrobalan seedlings infected with C. xenoplax caused lesions on the hypocotyls of young Myrobalan seedlings in the laboratory, but had no effect on older seedlings in the greenhouse, and did not alter the effect of C. xenoplax. PMID:19308143

  10. Pathogenicity of Criconemoides xenoplax to Prune and Plum Rootstocks.

    PubMed

    Mojtahedi, H; Lownsbery, B F

    1975-04-01

    Elimination of Criconemoides xenoplax from a prune orchard soil by fumigation with ethylene dibromide at the rate of 42 muliter/liter of soil (equivalent to about 13 gal/acre) improved the growth of Myrobalan plum, Addition of this nematode to Myrobalan seedlings or young 'Marianna 2624' plants propagated from cuttings resulted in destruction of cortical root tissue, darkening of roots, alteration of water stress, lowering of nutrient levels in leaves, and reduction in plant weight. C. xenoplax increased on all nine Prunus cerasifera varieties and hybrids tested, including those used commonly as rootstocks for prunes and plums. Rhizoctonia solani isolated from Myrobalan seedlings infected with C. xenoplax caused lesions on the hypocotyls of young Myrobalan seedlings in the laboratory, but had no effect on older seedlings in the greenhouse, and did not alter the effect of C. xenoplax.

  11. Public health assessment for petitioned public health assessment, Union Carbide (Byers Warehouse), St. Joseph, Buchanan County, Missouri, Region 7. Final report

    SciTech Connect

    Not Available

    1993-05-04

    In response to a petition from a St. Joseph, Missouri resident, the Agency for Toxic Substances and Disease Registry (ATSDR) conducted a public health assessment of the Union Carbide (Byers Warehouse) site in St. Joseph, Missouri. The basement of Byers Warehouse was used by Vulcan Chemicals to store ethylene dibromide (EDB), chloroform, and carbon tetrachloride (CCI4). The first and second floors were used by Union Carbide to store 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4,5-trichlorophenoxyproprionic acid (2,4,5-TP). The Byers Warehouse (Union Carbide) Petition site is not a current public health hazard. That conclusion is based on the complete removal of the toxic substances stored in the warehouse, and the lack of any current or future completed exposure pathways. Past storage of herbicides and other chemical products represented a public health hazard.

  12. Photochemical etching during ultraviolet photolytic deposition of metal films on semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Steven P.; Miller, D. L.

    1986-01-01

    UV photochemical deposition of Sn films on GaAs (001) surfaces from a variety of tin-containing compounds (tetramethyltin, tetrabutyltin, dibutyltin dibromide, stannic chloride, hexamethylditin, dibutyltin sulfide, and iodotrimethyltin) was studied. X-ray photoelectron spectroscopy showed that during the initial stages of deposition from the halogenated compounds, the GaAs surface was photochemically etched, most likely by a halogen radical species. The photochemical etching resulted in an arsenic deficient surface which was particularly dramatic for the case of SnCl4. These results have important implications for the choice of sources for photochemical deposition when the metal-semiconductor interface is important and for photochemical etching if stoichiometric surfaces are required.

  13. Photoinduced Intramolecular formal [4 + 2] Cycloaddition of Aryl-Substituted o-Vinylstyryl-2-oxazoles To Form Benzo[f]quinoline Derivatives: Experimental Results and Theoretical Interpretation.

    PubMed

    Šagud, Ivana; Antol, Ivana; Marinić, Željko; Šindler-Kulyk, Marija

    2015-10-02

    A new approach to benzo[f]quinoline derivatives has been found by an effective formal [4 + 2] photocycloaddition process from novel aryl-substituted o-vinylstyryl-2-oxazoles. All of the o-vinylstyryl-2-oxazoles were synthesized by a multicomponent Wittig reaction from the diphosphonium salt of α,α'-o-xylene dibromide, formaldehyde, and 5-tolyl-, 4-phenyl-5-methyl-, and 4,5-diphenyloxazole-2-carbaldehydes. TD-DFT calculations revealed that the intramolecular photocyclization in 2-(2-vinylstyryl)oxazoles to form benzo[f]quinoline derivatives proceeds on the S1 PES via a stepwise pathway, namely by 10π followed by 6π ring closure. On that path the existence of an S0/S1 conical intersection was indicated. The reactivity of the photocyclization steps depends on the substitution pattern at positions 4 and 5 of the oxazole ring, where the aryl group in position 5 deactivates the reaction.

  14. Ionol (BHT). Distribution in the organism, metabolism, and biological effect. II. Biological effects of ionol (survey)

    SciTech Connect

    Degterev, I.A.; Zaikov, G.E.

    1986-08-01

    In these experiments, a 25 mg/kg dose of ionol, administered to mice immediately after transplantation of melanoma B-16 or injection of tumor cells, inhibited the growth of pigmented B-16 cells and somewhat decreased the number of metastases. Ionol inhibited the mutagenic effect of benz(a)pyrene in vitro and in a culture of Salmonella typhimurium. In a mix with butylhydroxyanisole and propyl gallate, it decreased the number of mutations induced by gamma irradiation in the same culture. It protected mice from dominant lethal mutations and hereditary translocations induced by ethyl methanesulfonate (EMS). When ionol was present in the feed in a dose of 0.75% it reduced the lethal effect in mice of dimethylnitrosamine, EMS, ethylene dibromide and cyclophosphamide.

  15. NIOSH (National Institute for Occupational Safety and Health) manual of analytical methods (Third Edition). Second supplement

    SciTech Connect

    Not Available

    1987-08-15

    This supplement contains air and biological analytical methods which have been evaluated by NIOSH for use in determining concentrations of the following substances: acetaldehyde, alkaline dusts, aminoethanol compounds, arsenic, asbestos fibers, soluble barium, benzene, beryllium, biphenyl, bromotrifluoromethane, 1,3-butadiene, cadmium, chlorinated diphenyl ether, chloroacetic acid, diborane, dichlorodifluoromethane, 1,2-dichlorotetrafluoroethane, ethylene dibromide, ethylene oxide, fibers, furfural, halogenated hydrocarbons, iodine, methyl chloride, methyl ethyl ketone peroxide, methylene chloride, mineral oil mist, naphthylamines, nickel carbonyl, nitroethane, nitromethane, 2-nitropropane, organotin compounds, phosphorus, polychlorobenzenes, polychlorobiphenyls, pyridine, stibine, sulfur dioxide, tetrachlorodifluoroethanes, 1,1,2,2-tetrachloroethaylene, tetraethyl lead, toluene, toluene-2,4-diisocyanate, trichloroethylene, trichlorofluoromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, vanadium oxide, and vinylidene chloride.

  16. Synthesis of novel E-2-chlorovinyltellurium compounds based on the stereospecific anti-addition of tellurium tetrachloride to acetylene.

    PubMed

    Musalova, Maria V; Potapov, Vladimir A; Amosova, Svetlana V

    2012-05-15

    The reaction of tellurium tetrachloride with acetylene proceeds in a stereospecific anti-addition manner to afford the novel products E-2-chlorovinyltellurium trichloride and E,E-bis(2-chlorovinyl)tellurium dichloride. Reaction conditions for the selective preparation of each of these products were found. The latter was obtained in 90% yield in CHCl(3) under a pressure of acetylene of 10-15 atm, whereas the former product was formed in up to 72% yield in CCl(4) under a pressure of acetylene of 1-3 atm. Synthesis of the previously unknown E,E-bis(2-chlorovinyl) telluride, E,E-bis(2-chlorovinyl) ditelluride, E-2-chlorovinyl 1,2,2-trichloroethyl telluride and E,E-bis(2-chlorovinyl)-tellurium dibromide is described.

  17. A theoretical study of the oxidation of Hg0 to HgBr2 in the troposphere.

    PubMed

    Goodsite, M E; Plane, J M C; Skov, H

    2004-03-15

    The oxidation of elemental mercury (Hg0) to the divalent gaseous mercury dibromide (HgBr2) has been proposed to account for the removal of Hg0 during depletion events in the springtime Arctic. The mechanism of this process is explored in this paper by theoretical calculations of the relevant rate coefficients. Rice-Ramsberger-Kassel-Marcus (RRKM) theory, together with ab initio quantum calculations where required, are used to estimate the following: recombination rate coefficients of Hg with Br, I, and O; the thermal dissociation rate coefficient of HgBr; and the recombination rate coefficients of HgBr with Br, I, OH, and O2. A mechanism based on the initial recombination of Hg with Br, followed by the addition of a second radical (Br, I, or OH) in competition with thermal dissociation of HgBr, is able to account for the observed rate of Hg0 removal, both in Arctic depletion events and at lower latitudes.

  18. 1,1′-[(1,3-Dihydroxypropane-2,2-diyl)dimethylene]dipyridinium bis­(hexa­fluoro­phosphate)

    PubMed Central

    Yuan, Ai-lin; Zheng, Chun-ling; Zhuang, Ling-hua; Wang, Chang-sheng; Wang, Guo-wei

    2011-01-01

    The title compound, C15H20N2O2 2+·2PF6 −, was prepared by anion exchange of two bromide ions in the ionic liquid 2,2′-bis-(pyridinium-1-ylmeth­yl)-propane-1,3-diol dibromide with potassium hexa­fluoro­phosphate. The two pyridine rings are planar (r.m.s. deviations = 0.008 and 0.00440 Å) and make a dihedral angle of 44.0 (2)°. Intermolecular O—H⋯F and C—H⋯F interactions occur. The four F atoms in each anion were refined as disordered over two sets of sites with an occupancy ration of 0.700 (19):0.300 (19). PMID:21754422

  19. 1,1'-[(1,3-Dihydroxypropane-2,2-diyl)dimethylene]dipyridinium bis-(hexa-fluoro-phosphate).

    PubMed

    Yuan, Ai-Lin; Zheng, Chun-Ling; Zhuang, Ling-Hua; Wang, Chang-Sheng; Wang, Guo-Wei

    2011-05-01

    The title compound, C(15)H(20)N(2)O(2) (2+)·2PF(6) (-), was prepared by anion exchange of two bromide ions in the ionic liquid 2,2'-bis-(pyridinium-1-ylmeth-yl)-propane-1,3-diol dibromide with potassium hexa-fluoro-phosphate. The two pyridine rings are planar (r.m.s. deviations = 0.008 and 0.00440 Å) and make a dihedral angle of 44.0 (2)°. Intermolecular O-H⋯F and C-H⋯F interactions occur. The four F atoms in each anion were refined as disordered over two sets of sites with an occupancy ration of 0.700 (19):0.300 (19).

  20. Best Demonstrated Available Technology (BDAT) background document for newly listed wastes: K107, k108, k109, k110, k111, k112, u328, u353, k117, k118, k136, k123, k124, k125, k126, k131, k132, u359. Final technical report

    SciTech Connect

    1992-06-30

    The U.S. Environmental Protection Agency (the Agency or EPA) is establishing best demonstrated available technology (BDAT) treatment standards for the following listed hazardous wastes identified in Title 40, Code of Federal Regulations, Sections 261.32 and 261.33(f) (40 CFR 261.32 and 261.33(f)): 1,1-Dimethylhydrazine (UDMH) Production Wastes: K107, K108, K109, and K110; Dinitrotoluene (DNT) and Toluenediamine (TDA) Production Wastes: K111, K112, U328, and U353; Ethylene Dibromide (EDB) Production Wastes: K117, K118, and K136; Ethylenebisdithiocarbamic acid (EBDC) Production Wastes: K123, K124, K125, and K126; Methyl Bromide Production Wastes: K131 and K132; and 2-Ethoxyethanol Waste: U359.

  1. Ultrasound-assisted phase-transfer catalysis: benzoylation of sodium 4-acetylphenoxide by dual-site phase-transfer catalyst in a tri-liquid system.

    PubMed

    Yang, Hung-Ming; Chiu, Chun-Cheng

    2011-01-01

    A novel dual-site phase-transfer catalyst (PTC) was prepared and used to conduct the benzoylation of sodium 4-acetylphenoxide by ultrasound-assisted third-liquid phase-transfer catalysis. The catalyst 1,4-bis(tributylammoniomethyl)benzene dibromide (BTBAMBB) was synthesized from the reaction of p-xylylene dibromide and tributylamine in toluene at 70°C. The dual-site PTC was employed to form the third-liquid phase by extra addition of 0.04-0.05 mol of NaCl into 10 cm(3) of water. In the condition of 0.0425 mol of NaCl at 30°C, the catalytic intermediate in the third-liquid phase reached a maximum value. Almost 80% of the catalyst was transferred from the aqueous phase into the third-liquid phase. The distributions of the catalytic intermediate and dual-site PTC between phases and the kinetics of benzoylation of sodium 4-acetylphenoxide catalyzed by BTBAMBB with ultrasound irradiation were performed. The pseudo-first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (28 kHz/300 W) in a batch reactor, the yield of product 4-acetylphenyl benzoate in the organic phase was 98.1% in 2 min at 30°C and 250 rpm with the apparent rate constant k(app) to be 0.0075 s(-1), which was 6 times faster than that without using ultrasound (yield=14.4%, k(app)=0.0013 s(-1)). The present study provides a green method to synthesize esters by ultrasound-assisted third-liquid phase-transfer catalysis. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Characterization of a white-colour DBD-driven cadmium bromide exciplex lamp

    NASA Astrophysics Data System (ADS)

    Guivan, Mykola M.; Guyvan, Anna M.

    2010-10-01

    The emission spectra from an atmospheric-pressure gas-discharge plasma in mixtures of cadmium dibromide vapour with gases (Ne, Ar, Kr, Xe and N2), as well as the temporal characteristics of voltage and current, have been investigated. A dielectric barrier discharge at a repetition frequency of sinusoidal voltage pulses up to 140 kHz was used to create the gas-discharge plasma. The discharge radiation has been analysed in the spectral range 200-900 nm with a resolution of 0.05 nm. In the spectra, the study has revealed radiation from CdBr(B-X, C-X) exciplex molecules, atomic lines of cadmium and rare gases, and in mixtures with xenon, radiation of XeBr(B-X, B-A) exciplex molecules. The most intense CdBr(B-X) radiation was observed in CdBr2/Xe mixtures. A discharge radiation of a silvery-white colour was observed when the temperature of the mixture was above 250 °C. The XeBr(B-X) radiation predominated in the spectra at temperatures of the mixture up to 200 °C. A further increase in the temperature resulted in the prevalence of the CdBr(B-X) radiation. Regularities in the spectral characteristics of the radiation from the gas-discharge plasma are discussed. The high-frequency atmospheric-pressure barrier discharge in mixtures of cadmium dibromide with gases can be used in multiwave exciplex lamps, operating in the UV and visible regions.

  3. Assessment of potential aquatic herbicide impacts to California aquatic ecosystems.

    PubMed

    Siemering, Geoffrey S; Hayworth, Jennifer D; Greenfield, Ben K

    2008-10-01

    A series of legal decisions culminated in 2002 with the California State Water Resources Control Board funding the San Francisco Estuary Institute to develop and implement a 3-year monitoring program to determine the potential environmental impacts of aquatic herbicide applications. The monitoring program was intended to investigate the behavior of all aquatic pesticides in use in California, to determine potential impacts in a wide range of water-body types receiving applications, and to help regulators determine where to direct future resources. A tiered monitoring approach was developed to achieve a balance between program goals and what was practically achievable within the project time and budget constraints. Water, sediment, and biota were collected under "worst-case" scenarios in close association with herbicide applications. Applications of acrolein, copper sulfate, chelated copper, diquat dibromide, glyphosate, fluridone, triclopyr, and 2,4-D were monitored. A range of chemical analyses, toxicity tests, and bioassessments were conducted. At each site, risk quotients were calculated to determine potential impacts. For sediment-partitioning herbicides, sediment quality triad analysis was performed. Worst-case scenario monitoring and special studies showed limited short-term and no long-term toxicity directly attributable to aquatic herbicide applications. Risk quotient calculations called for additional risk characterizations; these included limited assessments for glyphosate and fluridone and more extensive risk assessments for diquat dibromide, chelated copper products, and copper sulfate. Use of surfactants in conjunction with aquatic herbicides was positively associated with greater ecosystem impacts. Results therefore warrant full risk characterization for all adjuvant compounds.

  4. Regio- and stereoselective isomerization of hexabromocyclododecanes (HBCDs): kinetics and mechanism of beta-HBCD racemization.

    PubMed

    Heeb, Norbert V; Schweizer, W Bernd; Mattrel, Peter; Haag, Regula; Kohler, Martin; Schmid, Peter; Zennegg, Markus; Wolfensberger, Max

    2008-04-01

    Hexabromocyclododecanes (HBCDs) are high production volume chemicals currently produced in quantities exceeding 20000ty(-1). They are used as flame retardants for plastics and textiles. HBCDs are thermally labile compounds, rapidly decomposing at temperatures above 250 degrees C to form bromine radicals, which scavenge other radicals formed during pyrolysis. But certain HBCD stereoisomers must reach the environment without decomposition, because their levels in soils, sediments, and biota are increasing worldwide. The fate of individual HBCD stereoisomers during production, product use, disposal, and transformation in the environment remains unclear. Herein we report on the thermally induced, highly selective isomerization of (+) and (-)beta-HBCD. Regio- and stereoselective migration of only two of the six bromine atoms resulted in the racemization of both beta-HBCDs. First order rate constants (k(rac)) increased from 0.005, 0.011, 0.021, to 0.055min(-1) at 130, 140, 150, and 160 degrees C, corresponding to half life times tau(1/2) of 143, 63, 29, and 14min, respectively. From the deduced kinetic model, we conclude that any thermal treatment of enantiomerically enriched beta-HBCDs in the range of 100-160 degrees C will result in a loss of most optical activity within few hours. The simultaneous inversion of two asymmetric centers occurred with perfect stereocontrol. Selectively, vicinal dibromides with the RR- and the SS-configurations migrated at these temperatures. An intramolecular reaction mechanism with a four-center transition state is postulated, based on the obtained stereoisomer pattern and the observed reaction kinetics. Crystal structure analysis revealed that all vicinal dibromides in beta-HBCDs prefer synclinal (gauche) conformations. However, an antiperiplanar (staggered) conformation is assumed to facilitate the concerted 1.2-shifts of both bromine atoms, resulting in an inversion of both neighboring carbon atoms. First experiments with other HBCD

  5. The isolation of coupled mitochondria from Physarum polycephalum and their response to Ca2+.

    PubMed

    Holmes, R P; Stewart, P R

    1979-01-11

    A method for the isolation of coupled mitochondria from the acellular slime mould Physarum polycephalum is described. The mitochondria oxidize respiratory substrates at rates comparable to those of mitochondria from other microorganisms and show similar responses to respiratory inhibitors. ADP/O values approach similar values to those obtained with mitochondria from higher organisms: 3 with NAD-linked substrates, 2 with succinate, and 1 with ascorbate-TMPD. Mitochondria actively take up low concentrations of Ca2+ with stimulation of their respiration. With succinate or pyruvate-malate as substrates respiratory responses are depressed by Ca2+ concentrations in excess of 200 micron in the presence or absence of phosphate. Exogenous NADH is unique in supporting the uptake of large amounts of Ca2+ in the presence of phosphate and in showing an unusual 'uncoupled' response in the absence of phosphate. A sigmoidal relationship occurs between initial velocity of Ca2+ uptake and Ca2+ concentration with a maximum velocity of approx. 15 nmol/s per mg protein and half maximum velocity occurring at approx. 50 micron Ca2+.

  6. Synchronization of calcium waves by mitochondrial substrates in Xenopus laevis oocytes

    NASA Astrophysics Data System (ADS)

    Jouaville, Laurence S.; Ichas, François; Holmuhamedov, Ekhson L.; Camacho, Patricia; Lechleiter, James D.

    1995-10-01

    INXenopus oocytes, as well as other cells, inositol-l,4,5-tris-phosphate (Ins(l,4,5)P3)-induced Ca2+ release1-4 is an excitable process that generates propagating Ca2+ waves5-7 that annihilate upon collision8-12. The fundamental property responsible for excitability13 appears to be the Ca2+ dependency of the Ins(l,4,5)P3 receptor9. Here we report that Ins(l,4,5)P3-induced Ca2+ wave activity is strengthened by oxidizable substrates that energize mitochondria, increasing Ca2+ wave amplitude, velocity and interwave period. The effects of pyruvate/malate are blocked by ruthenium red at the Ca2+ uniporter, by rotenone at complex I, and by antimycin A at complex III, and are subsequently rescued at complex IV by ascorbate tetramethylphenylenediamine (TMPD)14. Our data reveal that potential-driven mitochondrial Ca2+ uptake is a major factor in the regulation of Ins(l,4,5)P3-induced Ca2+ release and clearly demonstrate a physiological role of mitochondria in intracellular Ca2+ signalling.

  7. Correlation between surface free energy and anchoring energy of 6CHBT on polyimide surface

    NASA Astrophysics Data System (ADS)

    Borycki, Jerzy; Okulska-Bozek, Malgorzata; Kedzierski, Jerzy; Kojdecki, Marek A.

    2002-06-01

    Polyimides were prepared in the classical two-step method via poly(amic acids). Poly(amic acids) were obtained from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'- (hexafluoroisopropylidene)diphthalic anhydride (6FDA), pyromellitic dianhydride (PMDA), 3,3',4,4'- diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'- oxydiphthalic anhydride (ODPA) and amines 4,4'-oxydianiline (ODA), 1,3-phenylenediamine (MPD), 1,4-phenylenediamine (PPD), 4,4'-diaminodiphenylmethane (MDA), 4,4'- ethylenedianiline (DAB), 2,4,6-trimethyl-1,3- phenylenediamine (TMPD), 4-methyl-1,3-phenylenediamine (MMPD) and 2,3,5,6-tetramethyl-1,4-phenylenediamine (DAD) in dimethylformamide. The indium tin oxide (ITO)-glass plates were spin-coated with the poly(amic acids) solutions and dried. A thermal imidization process was then carried out at 250 degree(s)C for 4 h. In this study the anchoring energies of 6CHBT molecules were evaluated on rubbing aligning layers of PI films. The polar anchoring energy coefficient was determined by wedge cell method. The surface free energy and its components of polyimide layers were determined by measuring the contact angles of water, ethylene glycol, formamide and diiodomethane drops on the rubbing polymer surfaces. The Lifshitz-van der Waals and acidic-basic components of surface free energies were found from van Oss equation.

  8. Time-dependent density functional methods for Raman spectra in open-shell systems.

    PubMed

    Aquino, Fredy W; Schatz, George C

    2014-01-16

    We present an implementation of a time-dependent density functional theory (TD-DFT) linear response module in NWChem for unrestricted DFT calculations and apply it to the calculation of resonant Raman spectra in open-shell molecular systems using the short-time approximation. The new source code was validated and applied to simulate Raman spectra on several doublet organic radicals (e.g., benzyl, benzosemiquinone, TMPD, trans-stilbene anion and cation, and methyl viologen) and the metal complex copper phthalocyanine. We also introduce a divide-and-conquer approach for the evaluation of polarizabilities in relatively large systems (e.g., copper phthalocyanine). The implemented tool gives comparisons with experiment that are similar to what is commonly found for closed-shell systems, with good agreement for most features except for small frequency shifts, and occasionally large deviations for some modes that depend on the molecular system studied, experimental conditions not being accounted in the modeling such as solvation effects and extra solvent-based peaks, and approximations in the underlying theory. The approximations used in the quantum chemical modeling include (i) choice of exchange-correlation functional and basis set; (ii) harmonic approximation used in the frequency analysis to determine vibrational normal modes; and (iii) short-time approximation (omission of nuclear motion effects) used in calculating resonant Raman spectra.

  9. Effect of chronic ethanol consumption on the maximal respiratory capacity of rat liver mitochondria

    SciTech Connect

    Spach, P.I.; Cunningham, C.C.

    1986-05-01

    Previous observations suggest strongly that lowered ATP synthetase activity is responsible for the decrease in succinate-driven state 3 (+ ADP) respiration in liver mitochondria from rats fed ethanol chronically (ethanol mitochondria). In the present study uncoupler-stimulated respiration was measured to determine if ethanol-induced decreases in the concentrations of electron transport components were rate limiting for respiration in coupled ethanol mitochondria. Mitochondria were isolated from pair fed rats. Lowered state 3 respiration was observed in ethanol mitochondria with succinate, glutamate-malate, ..cap alpha..-ketoglutarate, and ascorbate-TMPD; cytochrome oxidase activity was decreased 25%. In contrast, uncoupler-stimulated rates were unchanged. These results demonstrate that maximal respiratory capacity is maintained in ethanol mitochondria, even when cytochrome oxidase is lowered. State 3 respiration at site 3, while significantly lowered in ethanol mitochondria, is still significantly higher than succinate-driven state 3 respiration in control mitochondria. These observations are, therefore, consistent with the suggestion that respiratory activity in coupled ethanol mitochondria (state 3 respiration) is limited by activities of other components of the oxidative-phosphorylation system, possibly the ATP synthetase complex.

  10. Methylmalonate inhibits succinate-supported oxygen consumption by interfering with mitochondrial succinate uptake.

    PubMed

    Mirandola, S R; Melo, D R; Schuck, P F; Ferreira, G C; Wajner, M; Castilho, R F

    2008-02-01

    The effect of methylmalonate (MMA) on mitochondrial succinate oxidation has received great attention since it could present an important role in energy metabolism impairment in methylmalonic acidaemia. In the present work, we show that while millimolar concentrations of MMA inhibit succinate-supported oxygen consumption by isolated rat brain or muscle mitochondria, there is no effect when either a pool of NADH-linked substrates or N,N,N',N'-tetramethyl-p-phenylendiamine (TMPD)/ascorbate were used as electron donors. Interestingly, the inhibitory effect of MMA, but not of malonate, on succinate-supported brain mitochondrial oxygen consumption was minimized when nonselective permeabilization of mitochondrial membranes was induced by alamethicin. In addition, only a slight inhibitory effect of MMA was observed on succinate-supported oxygen consumption by inside-out submitochondrial particles. In agreement with these observations, brain mitochondrial swelling experiments indicate that MMA is an important inhibitor of succinate transport by the dicarboxylate carrier. Under our experimental conditions, there was no evidence of malonate production in MMA-treated mitochondria. We conclude that MMA inhibits succinate-supported mitochondrial oxygen consumption by interfering with the uptake of this substrate. Although succinate generated outside the mitochondria is probably not a sig-nificant contributor to mitochondrial energy generation, the physiopathological implications of MMA-induced inhibition of substrate transport by the mitochondrial dicarboxylate carrier are discussed.

  11. Patterns of product inhibition for bacterial nitrite reductase.

    PubMed

    Dhesi, R; Timkovich, R

    1984-09-28

    Product inhibition has been examined in the turnover kinetics of cytochrome cd1 from Pseudomonas aeruginosa (ATCC 19429) and from Paracoccus denitrificans1 (ATCC 13456). A common characteristic was a decrease in rate during the time course of assays that was not due to substrate depletion or irreversible inactivation. The product of nitrite reduction, nitric oxide (NO), acted as a product inhibitor in anaerobic assays with an apparent Ki of 0.2 microM, but only if the enzyme was first preincubated with NO for 15 min. The enzyme was inhibited by the oxidized form of electron donors and this could account for the decrease in rate during an assay. For the donors hydroquinone, ascorbate, TMPD, and azurin, measured values of the inhibition constant were at least ten fold lower than measured Km's. Cytochromes c as donors demonstrated a complex pattern of product inhibition by the ferric form. Although numerical values of Ki in these cases were not obtained, trends indicated that apparent values would be less than Km.

  12. Studies on cytochrome c oxidase activity of the cytochrome c1aa3 complex from Thermus thermophilus.

    PubMed

    Yoshida, T; Fee, J A

    1984-01-25

    Cytochrome oxidase from T. thermophilus is isolated as a noncovalent complex of cytochromes c1 and aa3 in which the four redox components of aa3 appear to be associated with a single approximately 55,000-D subunit while the heme C is associated with a approximately 33,000-D peptide (Yoshida, T., Lorence, R. M., Choc, M. G., Tarr, G. E., Findling, K. L., and Fee, J. A. (1983) J. Biol. Chem. 258, 112-123). We have examined the steady state transfer of electrons from ascorbate to oxygen by cytochrome c1aa3 as mediated by horse heart, Candida krusei, and T. thermophilus (c552) cytochromes c as well as tetramethylphenylenediamine (TMPD). These mediators exhibit simple Michaelis-Menten kinetic behavior yielding Vmax and KM values characteristic of the experimental conditions. Three classes of kinetic behavior were observed and are qualitatively discussed in terms of a reaction scheme. The data show that tetramethylphenyldiamine and cytochromes c react with the enzyme at independent sites; it is suggested that cytochrome c1 may efficiently transfer electrons to cytochrome aa3. When incorporated into phospholipid vesicles, the highly purified cytochrome c1aa3 was found to translocate one proton into the exterior medium for each molecule of cytochrome c552 oxidized. The combined results suggest that this bacterial enzyme functions in a manner generally identical with the more complex eucaryotic enzyme.

  13. Functional reconstitution of the solubilized Arabidopsis thaliana STP1 monosaccharide-H+ symporter in lipid vesicles and purification of the histidine tagged protein from transgenic Saccharomyces cerevisiae.

    PubMed

    Stolz, J; Stadler, R; Opekarová, M; Sauer, N

    1994-08-01

    Complete DNA sequences encoding the Arabidopsis thaliana STP1 monosaccharide/H+ symporter or a histidine-tagged STP1-His6 protein were expressed in baker's yeast Saccharomyces cerevisiae. Both wild-type STP1 and the recombinant his-tagged protein were located in the plasma membranes of transformed yeast cells. The C-terminal modification caused no loss of transport activity compared with the wild-type protein. Anti-STP1-antibodies were used to confirm the identity of the protein in yeast and to compare the apparent molecular weights of STP1 proteins in membrane extracts from yeast or Arabidopsis thaliana. Purified yeast plasma membranes were fused with proteoliposomes consisting of Escherichia coli lipids and beef heart cytochrome-c oxidase. Addition of ascorbate/TMPD/cytochrome-c to these fused vesicles caused an immediate formation of membrane potential (inside negative; monitored with [3H]tetraphenylphosphonium cations) and a simultaneous, uncoupler-sensitive influx of D-glucose into the energized vesicles. STP1-His6 protein is functionally active after solubilization with octyl-beta-D-glucoside, which was shown by insertion of the protein into proteoliposomes by detergent dilution and determination of the resulting transport capacity. Detergent extracts from either total membranes or plasma membranes of transgenic yeast cells were used for one-step purification of the STP1-His6 protein on Ni(2+)-NTA columns. The identity of the purified protein was checked by immunoblotting and N-terminal sequencing.

  14. Involvement of chloroplasts in the programmed death of plant cells.

    PubMed

    Samuilov, V D; Lagunova, E M; Dzyubinskaya, E V; Izyumov, D S; Kiselevsky, D B; Makarova, Ya V

    2002-06-01

    The effect of cyanide, an apoptosis inducer, on pea leaf epidermal peels was investigated. Illumination stimulated the CN--induced destruction of guard cells (containing chloroplasts and mitochondria) but not of epidermal cells (containing mitochondria only). The process was prevented by antioxidants (alpha-tocopherol, 2,5-di-tret-butyl-4-hydroxytoluene, and mannitol), by anaerobiosis, by the protein kinase C inhibitor staurosporine, and by cysteine and serine protease inhibitors. Electron acceptors (menadione, p-benzoquinone, diaminodurene, TMPD, DCPIP, and methyl viologen) suppressed CN--induced apoptosis of guard cells, but not epidermal cells. Methyl viologen had no influence on the removal of CN--induced nucleus destruction in guard cells under anaerobic conditions. The light activation of CN--induced apoptosis of guard cells was suppressed by DCMU (an inhibitor of the electron transfer in Photosystem II) and by DNP-INT (an antagonist of plastoquinol at the Qo site of the chloroplast cytochrome b6f complex). It is concluded that apoptosis initiation in guard cells depends on the simultaneous availability of two factors, ROS and reduced quinones of the electron transfer chain. The conditions for manifestation of programmed cell death in guard and epidermal cells of the pea leaf were significantly different.

  15. Inhibition of cumene hydroperoxide-induced lipid peroxidation by a novel pyridoindole antioxidant in rat liver microsomes.

    PubMed

    Stefek, M; Masarykova, M; Benes, L

    1992-06-01

    The ability of stobadine, a novel pyridoindole antioxidant, to inhibit lipid peroxidation induced by cumene hydroperoxide was investigated in rat liver microsomes. In the micromolar range stobadine effectively inhibited lipid peroxidation as measured by the formation of thiobarbituric acid reactive products. The peroxidation-related degradation of microsomal cytochrome P-450 was prevented by stobadine in the same pattern. Another line of evidence in support of the antioxidant action of stobadine was given by its inhibition of cumene hydroperoxide-induced oxygen consumption in microsomal incubations. Inhibition of lipid peroxidation was not a function of decreased bioactivation of cumene hydroperoxide, as stobadine did not affect the rate of cytochrome P-450 dependent cleavage of cumene hydroperoxide. Neither had stobadine any effect on cytochrome P-450 peroxidase function characterized by the rate of cumene hydroperoxide-dependent oxidation of TMPD, and no direct spectral interaction with microsomal cytochrome P-450 was observed in the micromolar region. We suggest that it is the ability of stobadine to scavenge alkoxyl and peroxyl radicals that is predominantly responsible for the observed antioxidant effect.

  16. Electrochromic absorbance changes of photosynthetic pigments in Rhodopseudomonas sphaeroides. I. Stimulation by secondary electron transport at low temperature.

    PubMed

    de Grooth, B G; Amesz, J

    1977-11-17

    Light-induced absorbance changes were measured at temperatures between --30 and --55 degrees C in chromatophores of Rhodopseudomonas sphaeroides. Absorbance changes due to photooxidation of reaction center bacteriochlorophyll (P-870) were accompanied by a red shift of the absorption bands of a carotenoid. The red shift was inhibited by gramicidin D. The kinetics of P-870 indicated electron transport from the "primary" to a secondary electron acceptor. This electron transport was slowed down by lowering the temperature or increasing the pH of the suspension. Electron transport from soluble cytochrome c to P-870+ occurred in less purified chromatophore preparations. This electron transport was accompanied by a relatively large increase of the carotenoid absorbance change. This agrees with the hypothesis that P-870 is located inside the membrane, so that an additional membrane potential is generated upon transfer of an electron from cytochrome to P-870+. A strong stimulation of the carotenoid changes (more than 10-fold in some experiments) and pronounced band shifts of bacteriochlorophyll B-850 were observed upon illumination in the presence of artifical donor-acceptor systems. Reduced N-methylphenazonium methosulphate (PMS) and N,N,N',N'-tetramethyl-p-phenylene-diamine (TMPD) were fairly efficient donors, whereas endogenous ubiquinone and oxidized PMS acted as secondary acceptor. These results indicate the generation of large membrane potentials at low temperature, caused by sustained electron transport across the chromatophore membrane. The artificial probe, merocyanine MC-V did not show electrochromic band shifts at low temperature.

  17. Suppression of systemic autoimmunity by the innate immune adaptor STING

    PubMed Central

    Sharma, Shruti; Campbell, Allison M.; Chan, Jennie; Schattgen, Stefan A.; Orlowski, Gregory M.; Nayar, Ribhu; Huyler, Annie H.; Nündel, Kerstin; Mohan, Chandra; Berg, Leslie J.; Shlomchik, Mark J.; Marshak-Rothstein, Ann; Fitzgerald, Katherine A.

    2015-01-01

    Cytosolic DNA-sensing pathways that signal via Stimulator of interferon genes (STING) mediate immunity to pathogens and also promote autoimmune pathology in DNaseII- and DNaseIII-deficient mice. In contrast, we report here that STING potently suppresses inflammation in a model of systemic lupus erythematosus (SLE). Lymphoid hypertrophy, autoantibody production, serum cytokine levels, and other indicators of immune activation were markedly increased in STING-deficient autoimmune-prone mice compared with STING-sufficient littermates. As a result, STING-deficient autoimmune-prone mice had significantly shorter lifespans than controls. Importantly, Toll-like receptor (TLR)-dependent systemic inflammation during 2,6,10,14-tetramethylpentadecane (TMPD)-mediated peritonitis was similarly aggravated in STING-deficient mice. Mechanistically, STING-deficient macrophages failed to express negative regulators of immune activation and thus were hyperresponsive to TLR ligands, producing abnormally high levels of proinflammatory cytokines. This hyperreactivity corresponds to dramatically elevated numbers of inflammatory macrophages and granulocytes in vivo. Collectively these findings reveal an unexpected negative regulatory role for STING, having important implications for STING-directed therapies. PMID:25646421

  18. Repetitive Transient Depolarizations of the Inner Mitochondrial Membrane Induced by Proton Pumping

    PubMed Central

    Hattori, Tomohiro; Watanabe, Koichi; Uechi, Yukiko; Yoshioka, Hisashi; Ohta, Yoshihiro

    2005-01-01

    Single mitochondria show the spontaneous fluctuations of ΔΨm. In this study, to examine the mechanism of the fluctuations, we observed ΔΨm in single isolated heart mitochondria using time-resolved fluorescence microscopy. Addition of malate, succinate, or ascorbate plus TMPD to mitochondria induced polarization of the inner membrane followed by repeated cycles of rapid depolarizations and immediate repolarizations. ADP significantly decreased the frequency of the rapid depolarizations, but the ADP effect was counteracted by oligomycin. On the other hand, the rapid depolarizations did not occur when mitochondria were polarized by the efflux of K+ from the matrix. The rapid depolarizations became frequent with the increase in the substrate concentration or pH of the buffer. These results suggest that the rapid depolarizations depend on the net translocation of protons from the matrix. The frequency of the rapid depolarizations was not affected by ROS scavengers, Ca2+, CsA, or BA. In addition, the obvious increase in the permeability of the inner membrane to calcein (MW 623) that was entrapped in the matrix was not observed upon the transient depolarization. The mechanisms of the spontaneous oscillations of ΔΨm are discussed in relation to the matrix pH and the permeability transitions. PMID:15653749

  19. Examining the impact of the precision of address geocoding on estimated density of crime locations

    NASA Astrophysics Data System (ADS)

    Harada, Yutaka; Shimada, Takahito

    2006-10-01

    This study examines the impact of the precision of address geocoding on the estimated density of crime locations in a large urban area of Japan. The data consist of two separate sets of the same Penal Code offenses known to the police that occurred during a nine-month period of April 1, 2001 through December 31, 2001 in the central 23 wards of Tokyo. These two data sets are derived from older and newer recording system of the Tokyo Metropolitan Police Department (TMPD), which revised its crime reporting system in that year so that more precise location information than the previous years could be recorded. Each of these data sets was address-geocoded onto a large-scale digital map, using our hierarchical address-geocoding schema, and was examined how such differences in the precision of address information and the resulting differences in address-geocoded incidence locations affect the patterns in kernel density maps. An analysis using 11,096 pairs of incidences of residential burglary (each pair consists of the same incidents geocoded using older and newer address information, respectively) indicates that the kernel density estimation with a cell size of 25×25 m and a bandwidth of 500 m may work quite well in absorbing the poorer precision of geocoded locations based on data from older recording system, whereas in several areas where older recording system resulted in very poor precision level, the inaccuracy of incident locations may produce artifactitious and potentially misleading patterns in kernel density maps.

  20. Evidence for the presence of prostaglandin H synthase like enzyme in female Setaria cervi and its inhibition by diethylcarbamazine.

    PubMed

    Rathaur, Sushma; Singh, Alka; Yadav, Marshleen; Rai, Reeta

    2009-07-01

    Experimental evidence has shown that Setaria cervi a bovine filarial parasite contains significant amount of prostaglandin H synthase like activity in the somatic extract of its different life stages. A protein with characteristics of prostaglandin H synthase was purified to homogeneity from female somatic extract using a combination of affinity and gel filtration chromatography. Molecular weight of purified enzyme was 70kDa as determined by SDS-PAGE. Purified enzyme showed high activity with arachidonic acid and TMPD substrates suggests the presence of both cyclooxygenase and peroxidase activity in enzyme. Fluorescence spectroscopy and hemin-associated peroxidase activity confirmed presence of heme in purified enzyme. The K(m) and V(max) values using arachidonic acid were determined to be 79+/-1.5microM and 0.165+/-0.2U/ml, respectively. Further, indomethacin and aspirin, specific inhibitors for PGHS, significantly inhibited the enzyme activity. Diethylcarbamazine, an antifilarial drug inhibited the microfilarial PGHS like activity as well as their motility. Here we are reporting for the first time PGHS like activity in filarial parasite and its inhibition with DEC which provide that this enzyme could be used as a drug target.

  1. Apparent Km of mitochondria for oxygen computed from Vmax measured in permeabilized muscle fibers is lower in water enriched in oxygen by electrolysis than injection

    PubMed Central

    Zoll, Joffrey; Bouitbir, Jamal; Sirvent, Pascal; Klein, Alexis; Charton, Antoine; Jimenez, Liliana; Péronnet, François R; Geny, Bernard; Richard, Ruddy

    2015-01-01

    Background It has been suggested that oxygen (O2) diffusion could be favored in water enriched in O2 by a new electrolytic process because of O2 trapping in water superstructures (clathrates), which could reduce the local pressure/content relationships for O2 and facilitate O2 diffusion along PO2 gradients. Materials and methods Mitochondrial respiration was compared in situ in saponin-skinned fibers isolated from the soleus muscles of Wistar rats, in solution enriched in O2 by injection or the electrolytic process 1) at an O2 concentration decreasing from 240 µmol/L to 10 µmol/L (132 mmHg to 5 mmHg), with glutamate–malate or N, N, N′, N′-tetramethyl-p-phenylenediamine dihydrochloride (TMPD)–ascorbate (with antimycin A) as substrates; and 2) at increasing adenosine diphosphate (ADP) concentration with glutamate–malate as substrate. Results As expected, maximal respiration decreased with O2 concentration and, when compared to glutamate–malate, the apparent Km O2 of mitochondria for O2 was significantly lower with TMPD–ascorbate with both waters. However, when compared to the water enriched in O2 by injection, the Km O2 was significantly lower with both electron donors in water enriched in O2 by electrolysis. This was not associated with any increase in the sensitivity of mitochondria to ADP; no significant difference was observed for the Km ADP between the two waters. Conclusion In this experiment, a higher affinity of the mitochondria for O2 was observed in water enriched in O2 by electrolysis than by injection. This observation is consistent with the hypothesis that O2 diffusion can be facilitated in water enriched in O2 by the electrolytic process. PMID:26203225

  2. The effect of incomplete fuel-air mixing on the lean limit and emissions characteristics of a Lean Prevaporized Premixed (LPP) combustor

    NASA Technical Reports Server (NTRS)

    Santavicca, D. A.; Steinberger, R. L.; Gibbons, K. A.; Citeno, J. V.; Mills, S.

    1993-01-01

    Results are presented from an experimental study of the effect of incomplete fuel-air mixing on the lean limit and emissions characteristics of a lean, prevaporized, premixed (LPP), coaxial mixing tube combustor. Two-dimensional exciplex fluorescence was used to characterize the degree of fuel vaporization and mixing at the combustor inlet under non-combusting conditions. These tests were conducted at a pressure of 4 atm., a temperature of 400 C, a mixer tube velocity of 100 m/sec and an equivalence ratio of .8, using a mixture of tetradecane, 1 methyl naphthalene and TMPD as a fuel simulant. Fuel-air mixtures with two distinct spatial distributions were studied. The exciplex measurements showed that there was a significant amount of unvaporized fuel at the combustor entrance in both cases. One case, however, exhibited a very non-uniform distribution of fuel liquid and vapor at the combustor entrance, i.e., with most of the fuel in the upper half of the combustor tube, while in the other case, both the fuel liquid and vapor were much more uniformly distributed across the width of the combustor entrance. The lean limit and emissions measurements were all made at a pressure of 4 atm. and a mixer tube velocity of 100 m/sec, using Jet A fuel and both fuel-air mixture distributions. Contrary to what was expected, the better mixed case was found to have a substantially leaner operating limit. The two mixture distributions also unexpectedly resulted in comparable NO(x) emissions, for a given equivalence ratio and inlet temperature, however, lower NO(x) emissions were possible in the better mixed case due to its leaner operating limit.

  3. Protection of rat skeletal muscle fibers by either L-carnitine or coenzyme Q10 against statins toxicity mediated by mitochondrial reactive oxygen generation.

    PubMed

    La Guardia, P G; Alberici, L C; Ravagnani, F G; Catharino, R R; Vercesi, A E

    2013-01-01

    Mitochondrial redox imbalance has been implicated in mechanisms of aging, various degenerative diseases and drug-induced toxicity. Statins are safe and well-tolerated therapeutic drugs that occasionally induce myotoxicity such as myopathy and rhabdomyolysis. Previous studies indicate that myotoxicity caused by statins may be linked to impairment of mitochondrial functions. Here, we report that 1-h incubation of permeabilized rat soleus muscle fiber biopsies with increasing concentrations of simvastatin (1-40 μM) slowed the rates of ADP-or FCCP-stimulated respiration supported by glutamate/malate in a dose-dependent manner, but caused no changes in resting respiration rates. Simvastatin (1 μM) also inhibited the ADP-stimulated mitochondrial respiration supported by succinate by 24% but not by TMPD/ascorbate. Compatible with inhibition of respiration, 1 μM simvastatin stimulated lactate release from soleus muscle samples by 26%. Co-incubation of muscle samples with 1 mM L-carnitine, 100 μM mevalonate or 10 μM coenzyme Q10 (Co-Q10) abolished simvastatin effects on both mitochondrial glutamate/malate-supported respiration and lactate release. Simvastatin (1 μM) also caused a 2-fold increase in the rate of hydrogen peroxide generation and a decrease in Co-Q10 content by 44%. Mevalonate, Co-Q10 or L-carnitine protected against stimulation of hydrogen peroxide generation but only mevalonate prevented the decrease in Co-Q10 content. Thus, independently of Co-Q10 levels, L-carnitine prevented the toxic effects of simvastatin. This suggests that mitochondrial respiratory dysfunction induced by simvastatin, is associated with increased generation of superoxide, at the levels of complexes-I and II of the respiratory chain. In all cases the damage to these complexes, presumably at the level of 4Fe-4S clusters, is prevented by L-carnitine.

  4. Radiolytic reductions and oxidations in dimethyl sulfoxide solutions. Solvent effects on reactivity of halogen atom complexes

    SciTech Connect

    Kumar, M.; Neta, P.

    1992-04-16

    Radiolysis of dimethyl sulfoxide (DMSO) solutions containing various additives was used to achieve clean one-electron reduction or oxidation of solutes. Pulse radiolysis of benzoquinone in DMSO solutions containing acetone and triethylamine permitted conversion of all primary radicals into reducing species. The total yield of reduction in the {gamma}-radiolysis of methyl viologen solutions was found to be 0.37 {mu}mol/J. In the pulse radiolysis of TMPD and triphenylamine in aerated DMSO containing LiCl and/or CCl{sub 4}, all the primary radicals were converted into oxidizing species and gave a maximum yield of 0.39 {mu}mol/J. In the latter systems, oxidation, was partly by halogen atom complexes. The reactivity of complexes of DMSO (DMSO-Cl DMSO-Br) and of halide ions (Br{sub 2}{sup {sm_bullet}{minus}}, I{sub 2}{sup {sm_bullet}{minus}}) was examined for several organic compounds. DMSO-Cl oxidizes chlorpromazine triphenylamine, and zinc porphyrin with rate constants of the order of 10{sup 7}-10{sup 8} M{sup {minus}1}s{sup {minus}1}, and the rates increase upon addition of CH{sub 2}Cl{sub 2} as well as upon addition of water and formamide. DMSO-Cl also reacts with olefins by addition of Cl to the double bond; the rate constants increase upon increasing the electron-donating properties of the substituents on the double bond. The rate constants for oxidation of chlorpromazine by Br{sub 2}{sup {sm_bullet}{minus}} and I{sub 2}{sup {sm_bullet}{minus}} increase by more than 2 orders of magnitude upon changing the solvent from DMSO gradually to water. The change was less with acetonitrile/water mixtures, and the difference is probably due to differences in ion solvation. 28 refs., 3 figs., 4 tabs.

  5. Protection of rat skeletal muscle fibers by either L-carnitine or coenzyme Q10 against statins toxicity mediated by mitochondrial reactive oxygen generation

    PubMed Central

    La Guardia, P. G.; Alberici, L. C.; Ravagnani, F. G.; Catharino, R. R.; Vercesi, A. E.

    2013-01-01

    Mitochondrial redox imbalance has been implicated in mechanisms of aging, various degenerative diseases and drug-induced toxicity. Statins are safe and well-tolerated therapeutic drugs that occasionally induce myotoxicity such as myopathy and rhabdomyolysis. Previous studies indicate that myotoxicity caused by statins may be linked to impairment of mitochondrial functions. Here, we report that 1-h incubation of permeabilized rat soleus muscle fiber biopsies with increasing concentrations of simvastatin (1–40 μM) slowed the rates of ADP-or FCCP-stimulated respiration supported by glutamate/malate in a dose-dependent manner, but caused no changes in resting respiration rates. Simvastatin (1 μM) also inhibited the ADP-stimulated mitochondrial respiration supported by succinate by 24% but not by TMPD/ascorbate. Compatible with inhibition of respiration, 1 μM simvastatin stimulated lactate release from soleus muscle samples by 26%. Co-incubation of muscle samples with 1 mM L-carnitine, 100 μM mevalonate or 10 μM coenzyme Q10 (Co-Q10) abolished simvastatin effects on both mitochondrial glutamate/malate-supported respiration and lactate release. Simvastatin (1 μM) also caused a 2-fold increase in the rate of hydrogen peroxide generation and a decrease in Co-Q10 content by 44%. Mevalonate, Co-Q10 or L-carnitine protected against stimulation of hydrogen peroxide generation but only mevalonate prevented the decrease in Co-Q10 content. Thus, independently of Co-Q10 levels, L-carnitine prevented the toxic effects of simvastatin. This suggests that mitochondrial respiratory dysfunction induced by simvastatin, is associated with increased generation of superoxide, at the levels of complexes-I and II of the respiratory chain. In all cases the damage to these complexes, presumably at the level of 4Fe-4S clusters, is prevented by L-carnitine. PMID:23720630

  6. Effects of isoquinoline derivatives structurally related to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on mitochondrial respiration.

    PubMed

    McNaught, K S; Thull, U; Carrupt, P A; Altomare, C; Cellamare, S; Carotti, A; Testa, B; Jenner, P; Marsden, C D

    1996-06-14

    Isoquinoline derivatives exert 1-methyl-4-phenylpyridinium (MPP+)-like activity as inhibitors of complex I and alpha-ketoglutarate dehydrogenase activity in rat brain mitochondrial fragments. We now examine the ability of 19 isoquinoline derivatives and MPP+ to accumulate and inhibit respiration in intact rat liver mitochondria, assessed using polarographic techniques. None of the compounds examined inhibited respiration supported by either succinate + rotenone or tetramethylparaphenylenediamine (TMPD) + ascorbate. However, with glutamate + malate as substrates, 15 isoquinoline derivatives and MPP+ inhibited state 3 and, to a lesser extent, state 4 respiration in a time-dependent manner. None of the isoquinoline derivatives were more potent than MPP+. 6,7-Dimethoxy-1-styryl-3,4-dihydroisoquinoline uncoupled mitochondrial respiration. Qualitative structure-activity relationship studies revealed that isoquinolinium cations were more active than isoquinolines in inhibiting mitochondrial respiration; these, in turn, were more active than dihydroisoquinolines and 1,2,3,4-tetrahydroisoquinolines. Three-dimensional quantitative structure-activity relationship studies using Comparative Molecular Field Analysis showed that the inhibitory potency of isoquinoline derivatives was determined by steric, rather than electrostatic, properties of the compounds. A hypothetical binding site was identified that may be related to a rate-limiting transport process, rather than to enzyme inhibition. In conclusion, isoquinoline derivatives are less potent in inhibiting respiration in intact mitochondria than impairing complex I activity in mitochondrial fragments. This suggests that isoquinoline derivatives are not accumulated by mitochondria as avidly as MPP+. The activity of charged and neutral isoquinoline derivatives implicates both active and passive processes by which these compounds enter mitochondria, although the quaternary nitrogen moiety of the isoquinolinium cations favours

  7. Structural and functional alterations in mitochondrial membrane in picrotoxin-induced epileptic rat brain.

    PubMed

    Acharya, Munjal M; Katyare, Surendra S

    2005-03-01

    Mitochondrial function is a key determinant of both excitability and viability of neurons. Present studies were carried out to decipher cerebral mitochondrial oxidative energy metabolism and membrane function in the chronic condition of generalized seizures induced by picrotoxin (PTX) in rats. PTX-induced convulsions resulted in decreased respiration rates (14-41%) with glutamate, pyruvate + malate, and succinate as substrate. The ADP phosphorylation rates were drastically reduced by 44-65%. An opposite trend was observed with ascorbate + N,N,N',N'-tetramethyl-p-phenylenediamine [corrected] (TMPD) as substrate. In general, uncoupling of the mitochondrial electron transport was observed after PTX treatment. Malate dehydrogenase (MDH) and succinate dehydrogenase (SDH) activities were decreased by 20-80%; also, there was significant reduction in cytochrome b content after PTX treatment, while the F(o)F(1) ATPase (complex V) activity increased in basal and 2,4-dinitrophenol (DNP)-stimulated condition, indicating increased membrane fragility. The substrate kinetics analysis had shown that K(m) and V(max) of the higher affinity kinetic component of ATPase increased significantly by 1.2- to 1.4-fold in epileptic condition. Temperature kinetic analysis revealed 1.2-fold increase in energies of activation with decreased transition temperature. The total phospholipid (TPL) and cholesterol (CHL) contents decreased significantly with lowering of diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS), while lysophospholipid (lyso), sphingomyelin (SPM), and phosphatidylcholine components were found to be elevated. Brain mitochondrial membrane was somewhat more fluidized in epileptic animals. Possible consequences of mitochondrial respiratory chain (MRC) dysfunction are discussed. In conclusion, impairment of MRC function along with structural alterations suggests novel pathophysiological mechanisms important for

  8. Cytochrome bd from Escherichia coli catalyzes peroxynitrite decomposition.

    PubMed

    Borisov, Vitaliy B; Forte, Elena; Siletsky, Sergey A; Sarti, Paolo; Giuffrè, Alessandro

    2015-02-01

    Cytochrome bd is a prokaryotic respiratory quinol oxidase phylogenetically unrelated to heme-copper oxidases, that was found to promote virulence in some bacterial pathogens. Cytochrome bd from Escherichia coli was previously reported to contribute not only to proton motive force generation, but also to bacterial resistance to nitric oxide (NO) and hydrogen peroxide (H2O2). Here, we investigated the interaction of the purified enzyme with peroxynitrite (ONOO(-)), another harmful reactive species produced by the host to kill invading microorganisms. We found that addition of ONOO(-) to cytochrome bd in turnover with ascorbate and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) causes the irreversible inhibition of a small (≤15%) protein fraction, due to the NO generated from ONOO(-) and not to ONOO(-) itself. Consistently, addition of ONOO(-) to cells of the E. coli strain GO105/pTK1, expressing cytochrome bd as the only terminal oxidase, caused only a minor (≤5%) irreversible inhibition of O2 consumption, without measurable release of NO. Furthermore, by directly monitoring the kinetics of ONOO(-) decomposition by stopped-flow absorption spectroscopy, it was found that the purified E. coli cytochrome bd in turnover with O2 is able to metabolize ONOO(-) with an apparent turnover rate as high as ~10 mol ONOO(-) (mol enzyme)(-1) s(-1) at 25°C. To the best of our knowledge, this is the first time that the kinetics of ONOO(-) decomposition by a terminal oxidase has been investigated. These results strongly suggest a protective role of cytochrome bd against ONOO(-) damage. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Kinetic study of the quenching reaction of singlet oxygen by common synthetic antioxidants (tert-butylhydroxyanisol, tert-di-butylhydroxytoluene, and tert-butylhydroquinone) as compared with alpha-tocopherol.

    PubMed

    Kim, Ji In; Lee, Jun Hyun; Choi, Dong Seong; Won, Bo Mi; Jung, Mun Yhung; Park, Jiyong

    2009-06-01

    Effects of synthetic phenolic antioxidants (BHA, BHT, and TBHQ) on the methylene blue (MB) sensitized photooxidation of linoleic acid as compared with that of alpha-tocopherol have been studied. Their antioxidative mechanism was studied by both ESR spectroscopy in a 2,2,6,6-tetramethylpiperidone (TMPD)-methylene blue (MB) system and spectroscopic analysis of rubrene oxidation induced by a chemical source of singlet oxygen. Total singlet oxygen quenching rate constants (k(ox-Q)+k(q)) were determined using a steady state kinetic equation. TBHQ showed the strongest protective activity against the MB sensitized photooxidation of linoleic acid, followed by BHA and BHT. TBHQ (1 x 10(-3) M) exhibited 86.5% and 71.4% inhibition of peroxide and conjugated diene formations, respectively, in linoleic acid photooxidation after 60-min light illumination. The protective activity of TBHQ against the photosensitized oxidation of linoleic acid was almost comparable to that of alpha-tocopherol. The data obtained from ESR and rubrene oxidation studies clearly showed the strong singlet oxygen quenching ability of TBHQ. The k(ox-Q)+k(q) of BHA, BHT, and TBHQ were determined to be 3.37 x 10(7), 4.26 x 10(6), and 1.67 x 10(8) M(-1) s(-1), respectively. The k(ox-Q)+k(q) of TBHQ was within the same order of magnitude of that of alpha-tocopherol, a known efficient singlet oxygen quencher. There was a high negative correlation (r(2) = -0.991) between log (k(ox-Q)+k(q)) and reported oxidation potentials for the synthetic antioxidants, indicating their charge-transfer mechanism for singlet oxygen quenching. This is the 1st report on the kinetic study on k(ox-Q)+k(q) of TBHQ in methanol as compared with other commonly used commercial synthetic antioxidants and alpha-tocopherol.

  10. Quantitative imaging of a non-combusting diesel spray using structured laser illumination planar imaging

    NASA Astrophysics Data System (ADS)

    Berrocal, E.; Kristensson, E.; Hottenbach, P.; Aldén, M.; Grünefeld, G.

    2012-12-01

    Due to its transient nature, high atomization process, and rapid generation of fine evaporating droplets, diesel sprays have been, and still remain, one of the most challenging sprays to be fully analyzed and understood by means of non-intrusive diagnostics. The main limitation of laser techniques for quantitative measurements of diesel sprays concerns the detection of the multiple light scattering resulting from the high optical density of such a scattering medium. A second limitation is the extinction of the incident laser radiation as it crosses the spray, as well as the attenuation of the signal which is to be detected. All these issues have strongly motivated, during the past decade, the use of X-ray instead of visible light for dense spray diagnostics. However, we demonstrate in this paper that based on an affordable Nd:YAG laser system, structured laser illumination planar imaging (SLIPI) can provide accurate quantitative description of a non-reacting diesel spray injected at 1,100 bar within a room temperature vessel pressurized at 18.6 bar. The technique is used at λ = 355 nm excitation wavelength with 1.0 mol% TMPD dye concentration, for simultaneous LIF/Mie imaging. Furthermore, a novel dual-SLIPI configuration is tested with Mie scattering detection only. The results confirm that a mapping of both the droplet Sauter mean diameter and extinction coefficient can be obtained by such complementary approaches. These new insights are provided in this article at late times after injection start. It is demonstrated that the application of SLIPI to diesel sprays provides valuable quantitative information which was not previously accessible.

  11. Real-time monitoring of oxygen uptake in hepatic bioreactor shows CYP450-independent mitochondrial toxicity of acetaminophen and amiodarone.

    PubMed

    Prill, Sebastian; Bavli, Danny; Levy, Gahl; Ezra, Elishai; Schmälzlin, Elmar; Jaeger, Magnus S; Schwarz, Michael; Duschl, Claus; Cohen, Merav; Nahmias, Yaakov

    2016-05-01

    Prediction of drug-induced toxicity is complicated by the failure of animal models to extrapolate human response, especially during assessment of repeated dose toxicity for cosmetic or chronic drug treatments. In this work, we present a 3D microreactor capable of maintaining metabolically active HepG2/C3A spheroids for over 28 days in vitro under stable oxygen gradients mimicking the in vivo microenvironment. Mitochondrial respiration was monitored using two-frequency phase modulation of phosphorescent microprobes embedded in the tissue. Phase modulation is focus independent and unaffected by cell death or migration. This sensitive measurement of oxygen dynamics revealed important information on the drug mechanism of action and transient subthreshold effects. Specifically, exposure to antiarrhythmic agent, amiodarone, showed that both respiration and the time to onset of mitochondrial damage were dose dependent showing a TC50 of 425 μm. Analysis showed significant induction of both phospholipidosis and microvesicular steatosis during long-term exposure. Importantly, exposure to widely used analgesic, acetaminophen, caused an immediate, reversible, dose-dependent loss of oxygen uptake followed by a slow, irreversible, dose-independent death, with a TC50 of 12.3 mM. Transient loss of mitochondrial respiration was also detected below the threshold of acetaminophen toxicity. The phenomenon was repeated in HeLa cells that lack CYP2E1 and 3A4, and was blocked by preincubation with ascorbate and TMPD. These results mark the importance of tracing toxicity effects over time, suggesting a NAPQI-independent targeting of mitochondrial complex III might be responsible for acetaminophen toxicity in extrahepatic tissues.

  12. Fatty acid synthase inhibitors induce apoptosis in non-tumorigenic melan-a cells associated with inhibition of mitochondrial respiration.

    PubMed

    Rossato, Franco A; Zecchin, Karina G; La Guardia, Paolo G; Ortega, Rose M; Alberici, Luciane C; Costa, Rute A P; Catharino, Rodrigo R; Graner, Edgard; Castilho, Roger F; Vercesi, Aníbal E

    2014-01-01

    The metabolic enzyme fatty acid synthase (FASN) is responsible for the endogenous synthesis of palmitate, a saturated long-chain fatty acid. In contrast to most normal tissues, a variety of human cancers overexpress FASN. One such cancer is cutaneous melanoma, in which the level of FASN expression is associated with tumor invasion and poor prognosis. We previously reported that two FASN inhibitors, cerulenin and orlistat, induce apoptosis in B16-F10 mouse melanoma cells via the intrinsic apoptosis pathway. Here, we investigated the effects of these inhibitors on non-tumorigenic melan-a cells. Cerulenin and orlistat treatments were found to induce apoptosis and decrease cell proliferation, in addition to inducing the release of mitochondrial cytochrome c and activating caspases-9 and -3. Transfection with FASN siRNA did not result in apoptosis. Mass spectrometry analysis demonstrated that treatment with the FASN inhibitors did not alter either the mitochondrial free fatty acid content or composition. This result suggests that cerulenin- and orlistat-induced apoptosis events are independent of FASN inhibition. Analysis of the energy-linked functions of melan-a mitochondria demonstrated the inhibition of respiration, followed by a significant decrease in mitochondrial membrane potential (ΔΨm) and the stimulation of superoxide anion generation. The inhibition of NADH-linked substrate oxidation was approximately 40% and 61% for cerulenin and orlistat treatments, respectively, and the inhibition of succinate oxidation was approximately 46% and 52%, respectively. In contrast, no significant inhibition occurred when respiration was supported by the complex IV substrate N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). The protection conferred by the free radical scavenger N-acetyl-cysteine indicates that the FASN inhibitors induced apoptosis through an oxidative stress-associated mechanism. In combination, the present results demonstrate that cerulenin and orlistat induce

  13. Calcineurin transgenic mice have mitochondrial dysfunction and elevated superoxide production.

    PubMed

    Sayen, M R; Gustafsson, Asa B; Sussman, Mark A; Molkentin, Jeffery D; Gottlieb, Roberta A

    2003-02-01

    Introduction of the constitutively active calcineurin gene into neonatal rat cardiomyocytes by adenovirus resulted in decreased mitochondrial membrane potential (P < 0.05). Infection of H9c2 cells with calcineurin adenovirus resulted in increased superoxide production (P < 0.001). Transgenic mice with cardiac-specific expression of a constitutively active calcineurin cDNA (CalTG mice) exhibit a two- to threefold increase in heart size that progresses to heart failure. We prepared mitochondria enriched for the subsarcolemmal population from the hearts of CalTG mice and transgene negative littermates (control). Intact, well-coupled mitochondria prepared from one to two mouse hearts at a time yielded sufficient material for functional studies. Mitochondrial oxygen consumption was measured with a Clark-type oxygen electrode with substrates for mitochondrial complex II (succinate) and complex IV [tetramethylpentadecane (TMPD)/ascorbate]. CalTG mice exhibited a maximal rate of electron transfer in heart mitochondria that was reduced by approximately 50% (P < 0.002) without a loss of respiratory control. Mitochondrial respiration was unaffected in tropomodulin-overexpressing transgenic mice, another model of cardiomyopathy. Western blotting for mitochondrial electron transfer subunits from mitochondria of CalTG mice revealed a 20-30% reduction in subunit 3 of complex I (ND3) and subunits I and IV of cytochrome oxidase (CO-I, CO-IV) when normalized to total mitochondrial protein or to the adenine nucleotide transporter (ANT) and compared with littermate controls (P < 0.002). Impaired mitochondrial electron transport was associated with high levels of superoxide production in the CalTG mice. Taken together, these data indicate that calcineurin signaling affects mitochondrial energetics and superoxide production. The excessive production of superoxide may contribute to the development of cardiac failure.

  14. Participation of chloroplasts in plant apoptosis.

    PubMed

    Samuilov, Vitaly D; Lagunova, Elena M; Kiselevsky, Dmitry B; Dzyubinskaya, Elena V; Makarova, Yana V; Gusev, Mikhail V

    2003-01-01

    Mitochondria are known to participate in the initiation of programmed cell death (PCD) in animals and in plants. The role of chloroplasts in PCD is still unknown. We describe a new system to study PCD in plants; namely, leaf epidermal peels. The peel represents a monolayer consisting of cells of two types: phototrophic (guard cells) and chemotrophic (epidermal cells). The peels from pea (Pisum sativum L.) leaves were treated by cyanide as an inducer of PCD. We found an apoptosis-enhancing effect of illumination on chloroplast-containing guard cells, but not on chloroplastless epidermal cells. Antioxidants and anaerobiosis prevented the CN(-)-induced apoptosis of cells of both types in the dark and in the light. On the other hand, methyl viologen and menadione known as ROS-generating reagents as well as the Hill reaction electron acceptors (BQ, DAD, TMPD, or DPIP) that are not oxidized spontaneously by O2 were shown to prevent the CN(-)-induced nucleus destruction in guard cells. Apoptosis of epidermal cells was potentiated by these reagents, and they had no influence on the CN- effect. The light-dependent activation of CN(-)-induced apoptosis of guard cells was suppressed by DCMU, stigmatellin or DNP-INT, by a protein kinase inhibitor staurosporine as well as by cysteine and serine protease inhibitors. The above data suggest that apoptosis of guard cells is initiated upon a combined action of two factors, i.e., ROS and reduced plastoquinone of the photosynthetic electron transfer chain. As to reduction of ubiquinone in the mitochondrial respiratory chain, it seems to be antiapoptotic for the guard cell.

  15. Inhibition of photosynthetic oxygen evolution by protonophoric uncouplers.

    PubMed

    Samuilov, V D; Renger, G; Paschenko, V Z; Oleskin, A V; Gusev, M V; Gubanova, O N; Vasil'ev, S S; Barsky, E L

    1995-01-01

    The protonophoric uncouplers carbonyl cyanide m-chlorophenylhydrazone (CCCP), 2,3,4,5,6-pentachlorophenol (PCP) and 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole (TTFB) inhibited the Hill reaction with K3[Fe(CN)6] (but not with SiMo) in chloroplast and cyanobacterial membranes (the I50 values were approx. 1-2, 4-6 and 0.04-0.10 μM, respectively). The inhibition is due to oxidation of the uncouplers on the Photosystem II donor side (ADRY effect) and their subsequent reduction on the acceptor side, ie. to the formation of a cyclic electron transfer chain around Photosystem II involving the uncouplers as redox carriers. The relative amplitude of nanosecond chlorophyll fluorescence in chloroplasts was increased by DCMU or HQNO and did not change upon addition of uncouplers, DBMIB or DNP-INT; the HQNO effect was not removed by the uncouplers. The uncouplers did not inhibit the electron transfer from reduced TMPD or duroquinol to methylviologen which is driven by Photosystem I. These data show that CCCP, PCP and TTFB oxidized on the Photosystem II donor side are reduced by the membrane pool of plastoquinone (Qp) which is also the electron donor for K3 [Fe(CN)6] in the Hill reaction as deduced from the data obtained in the presence of inhibitors. Inhibition of the Hill reaction by the uncouplers was maximum at the pH values corresponding to the pK of these compounds. It is suggested that the tested uncouplers serve as proton donors, and not merely as electron donors on the oxidizing side of Photosystem II.

  16. Nek5 interacts with mitochondrial proteins and interferes negatively in mitochondrial mediated cell death and respiration.

    PubMed

    Melo Hanchuk, Talita D; Papa, Priscila Ferreira; La Guardia, Paolo G; Vercesi, Anibal E; Kobarg, Jörg

    2015-06-01

    Mitochondria are involved in energy supply, signaling, cell death and cellular differentiation and have been implicated in several human diseases. Neks (NIMA-related kinases) represent a family of mammal protein kinases that play essential roles in cell-cycle progression, but other functions have recently been related. A yeast two-hybrid (Y2H) screen was performed to identify and characterize Nek5 interaction partners and the mitochondrial proteins Cox11, MTX-2 and BCLAF1 were retrieved. Apoptosis assay showed protective effects of stable hNek5 expression from Hek293-T's cell death after thapsigargin treatment (2 μM). Nek5 silenced cells as well as cells expressing a "kinase dead" version of Nek5, displayed an increase in ROS formation after 4 h of thapsigargin treatment. Mitochondrial respiratory chain activity was found decreased upon stable hNek5expression. Cells silenced for hNek5 on the other hand presented 1.7 fold increased basal rates of respiration, especially at the electrons transfer steps from TMPD to cytochrome c and at the complex II. In conclusion, our data suggest for the first time mitochondrial localization and functions for Nek5 and its participation in cell death and cell respiration regulation. Stable expression of hNek5 in Hek293T cells resulted in enhanced cell viability, decreased cell death and drug resistance, while depletion of hNek5by shRNA overcame cancer cell drug resistance and induced apoptosis in vitro. Stable expression of hNek5 also inhibits thapsigargin promoted apoptosis and the respiratory chain complex IV in HEK293T cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Biochemical and Biophysical Characterization of the Two Isoforms of cbb3-Type Cytochrome c Oxidase from Pseudomonas stutzeri

    PubMed Central

    Xie, Hao; Buschmann, Sabine; Langer, Julian D.; Ludwig, Bernd

    2014-01-01

    The cbb3-type cytochrome c oxidases (cbb3-CcOs) are members of the heme-copper oxidase superfamily that couple the reduction of oxygen to translocation of protons across the membrane. The cbb3-CcOs are present only in bacteria and play a primary role in microaerobic respiration, being essential for nitrogen-fixing endosymbionts and for some human pathogens. As frequently observed in Pseudomonads, Pseudomonas stutzeri contains two independent ccoNO(Q)P operons encoding the two cbb3 isoforms, Cbb3-1 and Cbb3-2. While the crystal structure of Cbb3-1 from P. stutzeri was determined recently and cbb3-CcOs from other organisms were characterized functionally, less emphasis has been placed on the isoform-specific differences between the cbb3-CcOs. In this work, both isoforms were homologously expressed in P. stutzeri strains from which the genomic version of the respective operon was deleted. We purified both cbb3 isoforms separately by affinity chromatography and increased the yield of Cbb3-2 to a similar level as Cbb3-1 by replacing its native promoter. Mass spectrometry, UV-visible (UV-Vis) spectroscopy, differential scanning calorimetry, as well as oxygen reductase and catalase activity measurements were employed to characterize both cbb3 isoforms. Differences were found concerning the thermal stability and the presence of subunit CcoQ. However, no significant differences between the two isoforms were observed otherwise. Interestingly, a surprisingly high turnover of at least 2,000 electrons s−1 and a high Michaelis-Menten constant (Km ∼ 3.6 mM) using ascorbate–N,N,N′,N′-tetramethyl-p-phenylenediamine dihydrochloride (TMPD) as the electron donor were characteristic for both P. stutzeri cbb3-CcOs. Our work provides the basis for further mutagenesis studies of each of the two cbb3 isoforms specifically. PMID:24214947

  18. Fatty Acid Synthase Inhibitors Induce Apoptosis in Non-Tumorigenic Melan-A Cells Associated with Inhibition of Mitochondrial Respiration

    PubMed Central

    Rossato, Franco A.; Zecchin, Karina G.; La Guardia, Paolo G.; Ortega, Rose M.; Alberici, Luciane C.; Costa, Rute A. P.; Catharino, Rodrigo R.; Graner, Edgard; Castilho, Roger F.; Vercesi, Aníbal E.

    2014-01-01

    The metabolic enzyme fatty acid synthase (FASN) is responsible for the endogenous synthesis of palmitate, a saturated long-chain fatty acid. In contrast to most normal tissues, a variety of human cancers overexpress FASN. One such cancer is cutaneous melanoma, in which the level of FASN expression is associated with tumor invasion and poor prognosis. We previously reported that two FASN inhibitors, cerulenin and orlistat, induce apoptosis in B16-F10 mouse melanoma cells via the intrinsic apoptosis pathway. Here, we investigated the effects of these inhibitors on non-tumorigenic melan-a cells. Cerulenin and orlistat treatments were found to induce apoptosis and decrease cell proliferation, in addition to inducing the release of mitochondrial cytochrome c and activating caspases-9 and -3. Transfection with FASN siRNA did not result in apoptosis. Mass spectrometry analysis demonstrated that treatment with the FASN inhibitors did not alter either the mitochondrial free fatty acid content or composition. This result suggests that cerulenin- and orlistat-induced apoptosis events are independent of FASN inhibition. Analysis of the energy-linked functions of melan-a mitochondria demonstrated the inhibition of respiration, followed by a significant decrease in mitochondrial membrane potential (ΔΨm) and the stimulation of superoxide anion generation. The inhibition of NADH-linked substrate oxidation was approximately 40% and 61% for cerulenin and orlistat treatments, respectively, and the inhibition of succinate oxidation was approximately 46% and 52%, respectively. In contrast, no significant inhibition occurred when respiration was supported by the complex IV substrate N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD). The protection conferred by the free radical scavenger N-acetyl-cysteine indicates that the FASN inhibitors induced apoptosis through an oxidative stress-associated mechanism. In combination, the present results demonstrate that cerulenin and orlistat

  19. The effect of incomplete fuel-air mixing on the lean limit and emissions characteristics of a Lean Prevaporized Premixed (LPP) combustor

    NASA Technical Reports Server (NTRS)

    Santavicca, D. A.; Steinberger, R. L.; Gibbons, K. A.; Citeno, J. V.; Mills, S.

    1993-01-01

    Results are presented from an experimental study of the effect of incomplete fuel-air mixing on the lean limit and emissions characteristics of a lean, prevaporized, premixed (LPP), coaxial mixing tube combustor. Two-dimensional exciplex fluorescence was used to characterize the degree of fuel vaporization and mixing at the combustor inlet under non-combusting conditions. These tests were conducted at a pressure of 4 atm., a temperature of 400 C, a mixer tube velocity of 100 m/sec and an equivalence ratio of .8, using a mixture of tetradecane, 1 methyl naphthalene and TMPD as a fuel simulant. Fuel-air mixtures with two distinct spatial distributions were studied. The exciplex measurements showed that there was a significant amount of unvaporized fuel at the combustor entrance in both cases. One case, however, exhibited a very non-uniform distribution of fuel liquid and vapor at the combustor entrance, i.e., with most of the fuel in the upper half of the combustor tube, while in the other case, both the fuel liquid and vapor were much more uniformly distributed across the width of the combustor entrance. The lean limit and emissions measurements were all made at a pressure of 4 atm. and a mixer tube velocity of 100 m/sec, using Jet A fuel and both fuel-air mixture distributions. Contrary to what was expected, the better mixed case was found to have a substantially leaner operating limit. The two mixture distributions also unexpectedly resulted in comparable NO(x) emissions, for a given equivalence ratio and inlet temperature, however, lower NO(x) emissions were possible in the better mixed case due to its leaner operating limit.

  20. SO(2) saturation of the room temperature ionic liquid [C(2)mim][NTf(2)] much reduces the activation energy for diffusion.

    PubMed

    Barrosse-Antle, Laura E; Hardacre, Christopher; Compton, Richard G

    2009-01-29

    The physical effect of high concentrations of reversibly dissolved SO(2) on [C(2)mim][NTf(2)] was examined using cyclic voltammetry, chronoamperometry, and ESR spectroscopy. Cyclic voltammetry of the oxidation of solutions of ferrocene, N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), and chloride in the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium bis(trifluoromethanesufonyl)imide ([C(2)mim][NTf(2)]) reveals an increase in limiting current of each species corresponding to the addition of increasing concentrations of sulfur dioxide. Quantitative chronoamperometry reveals an increase in each species' diffusion coefficient with SO(2) concentration. When chronoamperometric data were obtained for ferrocene in [C(2)mim][NTf(2)] at a range of temperatures, the translational diffusion activation energy (29.0 +/- 0.5 kJ mol(- 1)) was found to be in good agreement with previous studies. Adding SO(2) results in apparent near-activationless translational diffusion. A significant decrease in the activation energy of rotational diffusion with the SO(2) saturation of a 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) solution in [C(2)mim][NTf(2)] (29.9 +/- 2.0 to 7.7 +/- 5.3 kJ mol(- 1)) was observed using electron spin resonance (ESR) spectroscopy. The reversible physical absorption of SO(2) by [C(2)mim][NTf(2)] should have no adverse effect on the ability of that ionic liquid to be employed as a solvent in an electrochemical gas sensor, and it is possible that the SO(2)-mediated reduction of RTIL viscosity could have intrinsic utility.

  1. Pyrrolnitrin from Burkholderia cepacia: antibiotic activity against fungi and novel activities against streptomycetes.

    PubMed

    el-Banna, N; Winkelmann, G

    1998-07-01

    A bacterial strain identified as Burkholderia cepacia NB-1 was isolated from water ponds in the botanical garden in Tübingen, Germany, and was found to produce a broad spectrum phenylpyrrole antimicrobial substance active against filamentous fungi, yeasts and Gram-positive bacteria. In batch culture containing glycerol and L-glutamic acid, the isolate NB-1 produced the antibiotic optimally late in the growth phase and accumulated a main portion in their cells. Isolation and purification of the antibiotic from Burkholderia (Pseudomonas) cepacia NB-1 by acetone extraction, gel filtration on Sephadex LH-20 and preparative HPLC yielded 0.54 mg l-1 of a pure substance. Spectroscopic data (HPLC, MS and NMR) confirmed that the compound was pyrrolnitrin [3-chloro-4-(2'-nitro-3'-chloro-phenyl) pyrrole]. Pyrrolnitrin has an inhibitory effect on the electron transport system, as demonstrated by isolated mitochondria from Neurospora crassa 74 A. This inhibition was relieved by N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD), indicating that pyrrolnitrin blocked the electron transfer between the dehydrogenases and the cytochrome components of the respiratory chain. Among Gram-positive bacteria, pyrrolnitrin was most active against certain Streptomyces species, especially S. antibioticus, which has not previously been described in the literature. In the presence of pyrrolnitrin, aerial mycelium and spore formation of Strep. antibioticus was suppressed, although growth continued via substrate mycelium. The new findings of inhibition of streptomycetes and their secondary metabolism by pyrrolnitrin may contribute to the fact that Pseudomonas species predominate in soil and compete even with antibiotic-producing Streptomyces.

  2. Rapid determination of fumigant and industrial chemical residues in food.

    PubMed

    Daft, J L

    1988-01-01

    A gas chromatographic (GC) method is described for the determination of 22 fumigant and industrial chemical residues in a variety of foods. The fumigants and industrial chemicals determined are methyl bromide, methylene chloride, carbon disulfide, chloroform, 1,1-dichloroethane, ethylene dichloride, methyl chloroform, carbon tetrachloride, methylene bromide, propylene dichloride, 2,3-dichloropropene, trichloroethylene, 1,3-dichloropropylene, 1,1,2-trichloroethane, chloropicrin, ethylene dibromide, tetrachloroethylene, propylene dibromide, 1,1,2,2-tetrachloroethane, p-dichlorobenzene, o-dichlorobenzene, and 1,2-dibromo-3-chloropropane. Except for the latter three, the fumigants are determined at 90 degrees C on 3.6 m 20% loaded OV-101 columns with electron-capture and Hall-electroconductivity detectors. The other 3 compounds (o-dichlorobenzene, p-dichlorobenzene, and 1,2-dibromo-3-chloropropane), which elute beyond 30 min on the above columns, are determined at 90 degrees C on 1.8 m 5% loaded OV-101 columns with the same detectors. The ng/g-level fortifications have an overall mean analyte recovery of 70% and a coefficient of variation of 40%. The variety of foods examined includes both fatty and nonfatty food types (e.g., off-the-shelf cooked and uncooked grain-based items, dairy products, fresh and canned fruits and vegetables, and meats). Samples are extracted and cleaned up according to fat content and food type. Samples containing less than 71% fat are extracted by using an aqueous: nonaqueous shakeout (20% acetone solution under isooctane). Most extracts (isooctanes) are analyzed directly. Extracts from samples containing from 21 to 70% fat (e.g., ground beef, pecans, and corn chips) are cleaned up further on micro-Florisil columns to remove excess fat. A few other samples containing more than 71% fat or oil (e.g., butter, salad dressing, and vegetable oil) are diluted directly in isooctane and, depending on the degree of dilution, can be cleaned up further on

  3. Equilibrium and kinetics studies of reactions of manganese acetate, cobalt acetate, and bromide salts in acetic acid solutions.

    PubMed

    Jiao, X D; Metelski, P D; Espenson, J H

    2001-06-18

    The oxidation of hydrogen bromide and alkali metal bromide salts to bromine in acetic acid by cobalt(III) acetate has been studied. The oxidation is inhibited by Mn(OAc)(2) and Co(OAc)(2), which lower the bromide concentration through complexation. Stability constants for Co(II)Br(n)() were redetermined in acetic acid containing 0.1% water as a function of temperature. This amount of water lowers the stability constant values as compared to glacial acetic acid. Mn(II)Br(n)() complexes were identified by UV-visible spectroscopy, and the stability constants for Mn(II)Br(n)() were determined by electrochemical methods. The kinetics of HBr oxidation shows that there is a new pathway in the presence of M(II)Br(n)(). Analysis of the concentration dependences shows that CoBr(2) and MnBr(2) are the principal and perhaps sole forms of the divalent metals that react with Co(III) and Mn(III). The interpretation of these data is in terms of this step (M, N = Mn or Co): M(OAc)(3) + N(II)Br(2) + HOAc --> M(OAc)(2) + N(III)Br(2)OAc. The second-order rate constants (L mol(-)(1) s(-)(1)) for different M, N pairs in glacial acetic acid are 4.8 (Co, Co at 40 degrees C), 0.96 (Mn, Co at 20 degrees C), 0.15 (Mn(III).Co(II), Co at 20 degrees C), and 0.07 (Mn, Mn at 20 degrees C). Following that, reductive elimination of the dibromide radical is proposed to occur: N(III)Br(2)OAc + HOAc --> N(OAc)(2) + HBr(2)(*). This finding implicates the dibromide radical as a key intermediate in this chemistry, and indeed in the cobalt-bromide catalyzed autoxidation of methylarenes, for which some form of zerovalent bromine has been identified. The selectivity for CoBr(2) and MnBr(2) is consistent with a pathway that forms this radical rather than bromine atoms which are at a considerably higher Gibbs energy. Mn(OAc)(3) oxidizes PhCH(2)Br, k = 1.3 L mol(-)(1) s(-)(1) at 50.0 degrees C in HOAc.

  4. Expression and characterization of recombinant Locusta migratoria manilensis acetylcholinesterase 1 in Pichia pastoris.

    PubMed

    Zhou, Xiaoxia; Xia, Yuxian

    2011-05-01

    The acetylcholinesterase 1 from Locusta migratoria manilensis (LmAChE1) was successfully expressed in methylotrophic yeast Pichia pastoris KM71. The maximum expression of recombinant LmAChE1 (reLmAChE1) was achieved after 9 days of induction at 2.5% methanol. The reLmAChE1 was first precipitated with ammonium sulfate (50% saturation) and then was purified with nickel affinity chromatography. The enzyme was purified 3.2×10(3)-fold with a yield of 68% and a specific activity of 8.1 U/mg. The purified reLmAChE1 exhibited highest activity at 30°C in 100 mM phosphate buffer (pH 7.4), and its activity could be inhibited by eserine sulfate and pentan-3-one-dibromide (BW284c51). Substrate specificity analysis showed that the purified reLmAChE1 preferred acetylthiocholine (ATC) and propionylthiocholine (BTC) rather than butyrylthiocholine (BTC). When ATC was used as substrate, the K(m) and V(max) values for the reLmAChE1 were 24.8 μM and 9.5 μmol/min/mg, respectively.

  5. Adaptation of microbial communities from an uncontaminated aquifer to degrade organic pollutants

    SciTech Connect

    Aelion, C.M.

    1988-01-01

    This study examined the ability of the microbial community from an uncontaminated aquifer to degrade and adapt to a variety of organic pollutants. Adaptation was defined functionally as an increase in the rate of mineralization of {sup 14}C-radiolabeled substrates with exposure to the chemical. Several patterns of microbial response to xenobiotic compounds were exhibited. For some compounds, such as chlorobenzene, 1,2,4-trichlorobenzene and toluene, limited mineralization was detected during greater than 8 months of incubation. Intermediate rates of biodegradation, and a linear increase in the percentage of substrate mineralized with time were observed for m-cresol, m-aminophenol and aniline. A maximum of 10 to 15% of the label added was respired during the 3 to 5 months incubation. Phenol, ethylene dibromide and p-chlorophenol were rapidly mineralized, to a maximum of 20 to 35% of the label added within the first few weeks of incubation. Of all the compounds examined, only p-nitrophenol and m-nitrophenol elicited an adaptation response in the microbial community.

  6. Adaptation to and biodegradation of xenobiotic compounds by microbial communities from a pristine aquifer

    SciTech Connect

    Aelion, C.M.; Swindoll, C.M.; Pfaender, F.K.

    1987-09-01

    The ability of subsurface microbial communities to adapt to the biodegradation of xenobiotic compounds was examined in aquifer solids samples from a pristine aquifer. An increase in the rates of mineralization of /sup 14/C labeled substrates with exposure was used as an indication of adaptation. For some compounds, such as chlorobenzene and 1,2,4-trichlorobenzene, slight mineralization was observed but no adaptation was apparent during incubations of over 8 months. Other compounds demonstrated three patterns of response. For m-cresol, m-aminophenol, and aniline intermediate rates of biodegradation and a linear increase in the percent mineralized with time were observed. Phenol, p-chlorophenol, and ethylene dibromide were rapidly metabolized initially, with a nonlinear increase in the percent mineralized with time, indicating that the community was already adapted to the biodegradation of these compounds. Only p-nitrophenol demonstrated a typical adaptation response. In different samples of soil from the same layer in the aquifer, the adaptation period to p-nitrophenol varied from a few days to as long as 6 weeks. In most cases the concentration of xenobiotic added, over the range from a few nanograms to micrograms per gram, made no difference in the response. Most-probably-number counts demonstrated that adaptation is accompanied by an increase in specific degrader numbers. This study has shown that diverse patterns of response occur in the subsurface microbial community.

  7. Protonation process of conjugated polyelectrolytes on enhanced power conversion efficiency in the inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Yi, Chao; Hu, Rong; Ren, He; Hu, Xiaowen; Wang, Shu; Gong, Xiong; Cao, Yong

    2014-01-01

    In this study, two conjugated polyelectrolytes, polythiophene derivative (PTP) and poly[(9,9-bis [6‧-N, N, N-trimethylammonium] hexyl)-fluorenylene-phenylene] dibromide (PFP), are utilized to modify the surface properties of ZnO electron extraction layer (EEL) in the inverted polymer solar cells (PSCs). Both higher short-circuit current densities and larger open-circuit voltages were observed from the inverted PSCs with ZnO/PFP or ZnO/PTP as compared with those only with ZnO EEL. The protonation process for PTP and PFP in solution is distinguished. Overall, more than 40% enhanced power conversion efficiency (PCE) from the inverted PSCs with ZnO/PFP, in which the PFP could be fully ionized in deionized water, and more than 30% enhanced PCE from the inverted PSCs with ZnO/PTP, as the case that the PTP could not be fully ionized in deionized water, as compared with the inverted PSCs with ZnO EEL were observed, respectively. These results demonstrate that the conjugated polyelectrolytes play an important role in enhancement of device performance of inverted PSCs and that the protonation process of the conjugated polyelectrolytes is critical to the modification for EEL in PSCs.

  8. Population dynamics of plant nematodes in cultivated soil: effects of combinations of cropping systems and nematicides.

    PubMed

    Murphy, W S; Brodie, B B; Good, J M

    1974-07-01

    The population density of Meloidogyne incognita was significantly reduced in land that was fallowed or cropped to crotalaria, marigold, bermudagrass, or bahiagrass. The rate of population decline caused by different cropping systems was influenced by initial population densities. Crotalaria, marigold, and bare fallow were about equally effective in reducing the density of M. incognita below dctectable lcvels, usually requiring 1-3 yr. Bahiagrass and bcrmudagrass required 4-5 yr or longer to reduce M. incognita below a detectable level. A high population density of Trichodorus christiei developed in land cropped 5 yr to bermudagrass, bahiagrass, okra, and marigold. Population densities of Pratylenchus brachyurus and Xiphinema americanum increased in land cropped to crotalaria or bermudagrass. Belonolabnus Iongicaudatus was detected only in land cropped to bermudagrass, The effectiveness of nematicides in reducing M. incognita infection was rclatcd to nematode population density resulting from 5 yr of different cropping systems. Treatment with aldicarb reduced M. incognita below detectable levels following all cropping systems; treatment with ethoprop following all cropping systems except okra, treatment wflh ethylene dibromide following bahiagrass or fallow; and treatment with DBCP only after 5 yr of fallow. Tomato transplant growth was affected .by both cropping systems and nematicide treatment. Transplants grown after crotalaria and bahiagrass were significantly larger than those grown after other crops. Also, treatment with aldicarb and ethoprop significantly increased transplant size.

  9. Effects and carry-over benefits of nematicides in soil planted to a sweet corn-squash-vetch cropping system.

    PubMed

    Johnson, A W; Leonard, R A

    1995-12-01

    The effects of irrigation on the efficacy of nematicides on Meloidogyne incognita race 1 population densities, yield of sweet corn, and the carry-over of nematicidal effect in the squash crop were determined in a sweet corn-squash-vetch cropping system for 3 years. Fenamiphos 15G and aldicarb 15G were applied at 6.7 kg a.i./ha and incorporated 15 cm deep with a tractor-mounted rototiller. Ethylene dibromide (EDB) was injected at 18 kg a.i./ha on each side of the sweet corn rows (total 36 kg a.i./ha) at planting for nematode control. Supplemental sprinkler irrigation (1.52-4.45 cm), applied in addition to natural rainfall (4.60-10.80 cm) within l0 days after application of nematicides, did not affect nematicide efficacy against M. incognita or yield of sweet corn. Soil treatment with fenamiphos, EDB, and aldicarb increased the number and total weight of sweet corn ears and the weight per ear each year over untreated controls (P

  10. Turbulence effects on volatilization rates of liquids and solutes

    USGS Publications Warehouse

    Lee, J.-F.; Chao, H.-P.; Chiou, C.T.; Manes, M.

    2004-01-01

    Volatilization rates of neat liquids (benzene, toluene, fluorobenzene, bromobenzene, ethylbenzene, m-xylene, o-xylene, o-dichlorobenzene, and 1-methylnaphthalene) and of solutes (phenol, m-cresol, benzene, toluene, ethylbenzene, o-xylene, and ethylene dibromide) from dilute water solutions have been measured in the laboratory over a wide range of air speeds and water-stirring rates. The overall transfer coefficients (KL) for individual solutes are independent of whether they are in single- or multi-solute solutions. The gas-film transfer coefficients (kG) for solutes in the two-film model, which have hitherto been estimated by extrapolation from reference coefficients, can now be determined directly from the volatilization rates of neatliquids through anew algorithm. The associated liquid-film transfer coefficients (KL) can then be obtained from measured KL and kG values and solute Henry law constants (H). This approach provides a novel means for checking the precision of any kL and kG estimation methods for ultimate prediction of KL. The improved kG estimation enables accurate K L predictions for low-volatility (i.e., low-H) solutes where K L and kGH are essentially equal. In addition, the prediction of KL values for high-volatility (i.e., high-H) solutes, where KL ??? kL, is also improved by using appropriate reference kL values.

  11. Health assessment for FMC Fresno National Priorities List (NPL) Site, Fresno, California, Region 9. CERCLIS No. CAD000629998. Preliminary report

    SciTech Connect

    Not Available

    1989-01-18

    The FMC Corporation Agricultural Chemical Group (FMC) Fresno plant has been proposed for the National Priorities List. FMC uses the plant to formulate pesticide products. Surface soil, subsurface soil, and ground water were sampled on- and off-site. No air sampling has been conducted. The soil samples identified several areas of contamination. Ground water samples show site related contaminants in the two upper water bearing zones of the Older Alluium Aquifer. The following contaminants are of public concern in the surface soil, subsurface soil, and groundwater: Toxaphene, DDD, DDT, DDE, BHC-beta, lindane, aldrin, endosulfan I, dieldrin, endosulfan II, methoxychlor, nitrate, 1,2-dichloropropane, pentachlorophenol, methyl ethyl ketone, methylene chloride, trichloroethylene, benefin, dibromochloropropane, casoron, and ethylene dibromide. The site is considered to be of public health concern because of the risk to human health caused by the likelihood of exposure to hazardous substances via inhalation of fugitive dust, ingestion of fugitive dust, soil, and ground water, and direct dermal contact with soil and ground water.

  12. Evaluation of oxime k203 as antidote in tabun poisoning.

    PubMed

    Kovarik, Zrinka; Vrdoljak, Ana Lucić; Berend, Suzana; Katalinić, Maja; Kuc, Kamil; Musilek, Kamil; Radić, Bozica

    2009-03-01

    We studied bispyridinium oxime K203 [(E)-1-(4-carbamoylpyridinium)-4-(4-hydroxyiminomethylpyridinium)-but-2-ene dibromide] with tabun-inhibited human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in vitro, and its antidotal effect on tabun-poisoned mice and rats in vivo. We compared it with oximes K048 and TMB-4, which have proven the most efficient oxime antidotes in tabun poisoning by now. Tabun-inhibited AChE was completely reactivated by K203, with the overall reactivation rate constant of 1806 L mol(-1) min(-1). This means that K203 is a very potent reactivator of tabun-inhibited AChE. In addition, K203 reversibly inhibited AChE (Ki = 0.090 mmol L(-1)) and BChE (K(i) = 0.91 mmol L(-1)), and exhibited its protective effect against phosphorylation of AChE by tabun in vitro. In vivo, a quarter of the LD50 K203 dose insured survival of all mice after the application of as many as 8 LD50 doses of tabun, which is the highest dosage obtained compared to K048 and TMB-4. Moreover, K203 showed high therapeutic potency in tabun-poisoned rats, preserving cholinesterase activity in rat plasma up to 60 min after poisoning. This therapeutic improvement obtained by K203 in tabun-poisoning places this oxime in the spotlight for further development.

  13. The antidotal efficacy of the bispyridinium oximes K027 and TMB-4 against tabun poisoning in mice.

    PubMed

    Berend, Suzana; Radić, Bozica; Kuca, Kamil; Lucić Vrdoljak, Ana

    2010-09-06

    A toxic effect of highly toxic nervous agents is irreversible inhibition of vitally important enzyme acethylcholinesterase (AChE). Inhibition of AChE results in accumulation of acetylcholine (ACh) at the synaptic cleft of the cholinergic neurons, leading to overstimulation of cholinergic receptors. The highly toxic nature of tabun has been known for many years, but there are still serious limitations to the antidotal therapy. In this paper a bispyridinium compound K027 [1-(4-hydroxyiminomethylpyridinium)-3-(-4-carbamoylpyridinium) propane dibromide] was tested as potential antidote in tabun poisoned mice. Oxime TMB-4 was included for comparison. The therapeutic efficacy of applied antidotal regimens was tested as pretreatment given 15 min before tabun poisoning and/or as therapy given 1 min after tabun poisoning. Using oxime K027 (25% of its LD(50)) plus atropine as both, pretreatment and therapy, we showed that this combination can protect mice 8 times better than the therapy alone. Under these experimental conditions we confirmed good antidotal efficacy of K027. Moreover, its low acute toxicity is as much as beneficial effect in contrast to high toxicity of currently used TMB-4.

  14. Ultrasound assisted free radical polymerization of glycidyl methacrylate by a new disite phase-transfer catalyst system: A kinetic study.

    PubMed

    Sankar, Kavitha; Rajendran, Venugopal

    2012-11-01

    The kinetics of multi-site phase-transfer catalyzed free radical polymerisation of glycidyl methacrylate (GMA) using potassium peroxy disulphate (PDS) as water soluble initiator and newly synthesized 1,4-dihexadecylpyrazine-1,4-diium dibromide as multi-site phase-transfer catalyst (MPTC) has been investigated in ethyl acetate/water two phase system at constant temperature 65±1°C under nitrogen atmosphere and ultrasound irradiation conditions. The rate of polymerization increases with an increase in concentrations of GMA, PDS and MPTC. The order with respect to monomer, initiator and MPTC were found to be 1.0, 0.5 and 1.0, respectively. The comparative study reveals that the Rp of GMA determined in the presence of PTC combined with ultrasound has shown more enhancements in the activity than PTC alone. Based on the observed results a suitable mechanism has been proposed to account for the experimental observations and its significance was discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Sonication effect on the reaction of 4-bromo-1-methylbenzene with sodium sulfide in liquid-liquid multi-site phase-transfer catalysis condition - kinetic study.

    PubMed

    Abimannan, Pachaiyappan; Selvaraj, Varathan; Rajendran, Venugopal

    2015-03-01

    The synthesis of di-p-tolylsulfane from the reaction of 4-bromo-1-methylbenzene (BMB) with sodium sulfide was carried out using a multi-site phase-transfer catalyst (MPTC) viz., 1,4-dihexyl-1,4-diazoniabicyclo[2.2.2]octanium dibromide and ultrasonic irradiation in a liquid-liquid reaction condition. The overall reaction rate is greatly enhanced when catalyzed by multi-site phase-transfer catalyst (MPTC) combined with sonication (40 kHz, 300 W) in a batch reactor than catalyzed by MPTC without sonication. Effects on the reaction due to various operating conditions, such as agitation speed, different ultrasound frequencies, different phase-transfer catalysts, different organic solvents, the amount of MPTC, temperature, amount of sodium sulfide, effect of sodium hydroxide, volume of n-hexane and the concentration of 4-bromo-1-methylbenzene. The reaction obeys a pseudo first-order rate law and a suitable mechanism was proposed based on the experimental observation. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. The hazard evaluation system and information service: a physician's resource in toxicology and occupational medicine.

    PubMed

    Hooper, K

    1982-12-01

    Hazard evaluation is an emerging science. The Hazard Evaluation System and Information Service (HESIS), part of California's program in preventive occupational health, is a resource for clinicians who wish to stay abreast of the relationship between toxicology and occupational health. For example, advances in assays for cancer or reproductive effects in test animals enable us to identify with greater confidence significant cancer or reproductive hazards among the increasing variety of workplace exposures. Occupational experiences with dibromochloropropane (DBCP), Kepone, bis(chloromethyl) ether, benzidine and vinyl chloride demonstrate the shortcomings of relying on human data. The latency period of cancer, limited sensitivity of epidemiologic studies and severity of effects require us to use animal test data to evaluate the potential cancer and reproductive risks of workplace substances. HESIS gives appropriate weight to experimental data in hazard evaluations of chemicals such as ethylene oxide, ethylene dibromide, polychlorinated biphenyls and the glycol ethers. A similar approach is apparent in the California Department of Health Services' recently released Carcinogen Identification Policy.

  17. Opposing effects of oxidative challenge and carotenoids on antioxidant status and condition-dependent sexual signalling

    PubMed Central

    Tomášek, Oldřich; Gabrielová, Barbora; Kačer, Petr; Maršík, Petr; Svobodová, Jana; Syslová, Kamila; Vinkler, Michal; Albrecht, Tomáš

    2016-01-01

    Several recent hypotheses consider oxidative stress to be a primary constraint ensuring honesty of condition-dependent carotenoid-based signalling. The key testable difference between these hypotheses is the assumed importance of carotenoids for redox homeostasis, with carotenoids being either antioxidant, pro-oxidant or unimportant. We tested the role of carotenoids in redox balance and sexual signalling by exposing adult male zebra finches (Taeniopygia guttata) to oxidative challenge (diquat dibromide) and manipulating carotenoid intake. As the current controversy over the importance of carotenoids as antioxidants could stem from the hydrophilic basis of commonly-used antioxidant assays, we used the novel measure of in vivo lipophilic antioxidant capacity. Oxidative challenge reduced beak pigmentation but elicited an increase in antioxidant capacity suggesting resource reallocation from signalling to redox homeostasis. Carotenoids counteracted the effect of oxidative challenge on lipophilic (but not hydrophilic) antioxidant capacity, thereby supporting carotenoid antioxidant function in vivo. This is inconsistent with hypotheses proposing that signalling honesty is maintained through either ROS-induced carotenoid degradation or the pro-oxidant effect of high levels of carotenoid-cleavage products acting as a physiological handicap. Our data further suggest that assessment of lipophilic antioxidant capacity is necessary to fully understand the role of redox processes in ecology and evolution. PMID:27000655

  18. Hydroxyl radical substitution in halogenated carbonyls: oxalic acid formation.

    PubMed

    Christiansen, Carrie J; Dalal, Shakeel S; Francisco, Joseph S; Mebel, Alexander M; Gaffney, Jeffrey S

    2010-03-04

    An ab initio study of OH radical substitution reactions in halogenated carbonyls is conducted. Hydroxyl radical substitution into oxalyl dichloride [ClC(O)C(O)Cl] and oxalyl dibromide [BrC(O)C(O)Br], resulting in the formation of oxalic acid, is presented. Analogous substitution reactions in formyl chloride [ClCH(O)], acetyl chloride [ClC(O)CH(3)], formyl bromide [BrCH(O)], and acetyl bromide [BrC(O)CH(3)] are considered. Energetics of competing hydrogen abstraction reactions for all applicable species are computed for comparison. Geometry optimizations and frequency computations are performed using the second-order Møller-Plesset perturbation theory (MP2) and the 6-31G(d) basis set for all minimum species and transition states. Single point energy computations are performed using fourth-order Møller-Plesset perturbation theory (MP4) and coupled cluster theory [CCSD(T)]. Potential energy surfaces, including activation energies and enthalpies, are determined from the computations. These potential energy surfaces show that OH substitution into ClC(O)C(O)Cl and BrC(O)C(O)Br, resulting in the formation of oxalic acid and other minor products, is energetically favorable. Energetics of analogous reactions with ClCH(O), BrCH(O), ClC(O)CH(3), and BrC(O)CH(3) are also computed.

  19. Hitching a Ride on Vesicles: Cauliflower Mosaic Virus Movement Protein Trafficking in the Endomembrane System1[W][OPEN

    PubMed Central

    Carluccio, Anna Vittoria; Zicca, Stefania; Stavolone, Livia

    2014-01-01

    The transport of a viral genome from cell to cell is enabled by movement proteins (MPs) targeting the cell periphery to mediate the gating of plasmodesmata. Given their essential role in the development of viral infection, understanding the regulation of MPs is of great importance. Here, we show that cauliflower mosaic virus (CaMV) MP contains three tyrosine-based sorting signals that interact with an Arabidopsis (Arabidopsis thaliana) μA-adaptin subunit. Fluorophore-tagged MP is incorporated into vesicles labeled with the endocytic tracer N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide. The presence of at least one of the three endocytosis motifs is essential for internalization of the protein from the plasma membrane to early endosomes, for tubule formation, and for CaMV infection. In addition, we show that MP colocalizes in vesicles with the Rab GTPase AtRAB-F2b, which is resident in prevacuolar late endosomal compartments that deliver proteins to the vacuole for degradation. Altogether, these results demonstrate that CaMV MP traffics in the endocytic pathway and that virus viability depends on functional host endomembranes. PMID:24477592

  20. The bilateral action between EQ14-2-14 gemini surfactant and bovine serum albumin by DPI and 1H NMR

    NASA Astrophysics Data System (ADS)

    Wu, Gang; Jiang, Xiaohui; Zhou, Limei; Yang, Lijun; Wang, Ya; Xia, Guangqiang; Chen, Zhengjun; Duan, Ming

    2013-08-01

    Gemini surfactant diglycol bis-N-tetradecyl nicotinate dibromide (designed as EQ14-2-14) has been synthesized. The interaction between EQ14-2-14 and bovine serum albumin (BSA) was studied by dual polarization interferometry (DPI), proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier transform infrared spectroscopy (FTIR) and molecular docking. Owing to the binding of EQ14-2-14, the thickness and mass of BSA increased; refractive index (RI) and density firstly raised and then tended to a plateau. In addition, a decrease of α-helix was observed from 54.01% to 31.56% with an increase in random structure from 7.86% to 21.76%. Due to BSA intertwining, the proton resonance signals of EQ14-2-14 shifted up-field and relaxation time decreased with increasing concentration of BSA. The study of molecular docking indicated that EQ14-2-14 embedded into subdomain II of BSA by π-π stacking between the electron-deficit pyridinium rings in EQ14-2-14 and the electron-abundant pyrrole ring in Trp residues of BSA, by hydrogen bonding and by hydrophobic interaction. Therefore the present work offers a whole view of the interaction of BSA with a new gemini surfactant.

  1. Selective palladation of a large (32 ring atom) macrocyclic ligand at a bis(N-heterocyclic carbene) coordination pocket through transmetallation of the corresponding mercury(II) derivative.

    PubMed

    Meyer, Kim; Dalebrook, Andrew F; Wright, L James

    2012-12-14

    Treatment of N(2),N(6)-bis(6-acrylamidopyridin-2-yl)pyridine-2,6-dicarboxamide with benzimidazole gives the acyclic aza-Michael addition product N(2),N(6)-bis(6-(3-(1H-benzo[d]imidazol-1-yl)propanamido)pyridin-2-yl)pyridine-2,6-dicarboxamide (2). The macrocycle N(1),N(7)-pyridine-2,6-dimethyl-N(2),N(6)-bis(6-(3-(1H-benzo[d]imidazol-1-yl)propanamido)pyridin-2-yl)pyridine-2,6-dicarboxamide dibromide ([H(2)L(2)]Br(2)) is formed through the double alkylation of 2 with 2,6-bis(bromomethyl)pyridine. The imidazole analogues of 2 and [H(2)L(2)]Br(2) (1 and [H(2)L(1)]Br(2), respectively) have also been prepared. Mercuration of the two benzimidazolium groups in [H(2)L(2)]Br(2) with mercury(II) acetate in the presence of [N(CH(3))(4)](2)[HgBr(4)] proceeds to give [HgL(2)][HgBr(4)] in good yield. The ability of [HgL(2)][HgBr(4)] to readily partake in transmetallation reactions is demonstrated by the reaction that occurs with PdCl(2)(COD) to form [PdClL(2)][PF(6)]. The structures of 2, [HgL(2)][HgBr(4)] and [PdClL(2)][PF(6)] have been determined.

  2. DNA single-strand breaks, double-strand breaks, and crosslinks in rat testicular germ cells: Measurements of their formation and repair by alkaline and neutral filter elution

    SciTech Connect

    Bradley, M.O.; Dysart, G. )

    1985-06-01

    This work describes a neutral and alkaline elution method for measuring DNA single-strand breaks (SSBs), DNA double-strand breaks (DSBs), and DNA-DNA crosslinks in rat testicular germ cells after treatments in vivo or in vitro with both chemical mutagens and gamma-irradiation. The methods depend upon the isolation of testicular germ cells by collagenase and trypsin digestion, followed by filtration and centrifugation. {sup 137}Cs irradiation induced both DNA SSBs and DSBs in germ cells held on ice in vitro. Irradiation of the whole animal indicated that both types of DNA breaks are induced in vivo and can be repaired. A number of germ cell mutagens induced either DNA SSBs, DSBs, or cross-links after in vivo and in vitro dosing. These chemicals included methyl methanesulfonate, ethyl methanesulfonate, ethyl nitrosourea, dibromochlorpropane, ethylene dibromide, triethylene melamine, and mitomycin C. These results suggest that the blood-testes barrier is relatively ineffective for these mutagens, which may explain in part their in vivo mutagenic potency. This assay should be a useful screen for detecting chemical attack upon male germ-cell DNA and thus, it should help in the assessment of the mutagenic risk of chemicals. In addition, this approach can be used to study the processes of SSB, DSB, and crosslink repair in DNA of male germ cells, either from all stages or specific stages of development.

  3. Adsorption of cationic monomeric and gemini surfactants on montmorillonite and adsolubilization of vitamin E.

    PubMed

    Sakai, Kenichi; Nakajima, Erimi; Takamatsu, Yuichiro; Sharma, Suraj C; Torigoe, Kanjiro; Yoshimura, Tomokazu; Esumi, Kunio; Sakai, Hideki; Abe, Masahiko

    2008-01-01

    Adsorption of a cationic gemini surfactant (1,2-bis(dodecyldimethylammonio) ethane dibromide, 12-2-12) and the corresponding monomeric surfactant (dodecyltrimethylammonium bromide, DTAB) on montmorillonite has been characterized with a combination of adsorption isotherm, interlayer spacing and FT-IR spectroscopic data. Adsolubilization of vitamin E into the adsorbed surfactant layers has also been studied. The adsorption isotherm data reveal that the adsorption of the two surfactants is driven by the two factors: one is the cation exchange that occurs on the interlayer basal planes and the other is the hydrophobic interaction between hydrocarbon chains of the surfactants. Although the adsorbed amount measured in the saturation region (in mol g(-1)) is almost identical for the two surfactants, the conformation of the intercalated surfactant molecules differs significantly from each other. The adsorption of DTAB results in a lateral bilayer arrangement in the limited interlayer space, whereas 12-2-12 gives a normal bilayer arrangement in the expanded interlayer space. Adsolubilization of vitamin E takes place into the adsorbed surfactant layers, and interestingly, all the vitamin E molecules added in the montmorillonite suspensions are hybridized at lower surfactant concentrations due to the great specific surface area of the clay material. Since the maximum adsolubilization amount is usually obtained just below the critical micelle concentration, the gemini surfactant is deemed to be more efficient than the corresponding monomeric one to achieve the great adsolubilization amount.

  4. Manganese powder promoted highly efficient and selective synthesis of fullerene mono- and biscycloadducts at room temperature

    NASA Astrophysics Data System (ADS)

    Si, Weili; Zhang, Xuan; Lu, Shirong; Yasuda, Takeshi; Asao, Naoki; Han, Liyuan; Yamamoto, Yoshinori; Jin, Tienan

    2015-09-01

    Discovery of an efficient, practical, and flexible synthetic method to produce various important electron acceptors for low-cost organic photovoltaics (OPVs) is highly desirable. Although the most commonly used acceptor materials, such as PC61BM, PC71BM, IC60BA, bisPC61BM have been proved to be promising for the OPVs, they are still very expensive mainly due to their low production yields and limited synthetic methods. Herein, we report an unprecedented and innovative synthetic method of a variety of fullerene mono- and biscycloadducts by using manganese powder as a promotor. The reaction of fullerenes with various dibromides proceeds efficiently and selectively under very mild conditions to give the corresponding cycloadducts in good to excellent yields. The combination of manganese power with DMSO additive is crucial for the successful implementation of the present cycloaddition. Notably, the standard OPV acceptors, such as PCBMs, have been obtained in extraordinarily high yields, which cannot be achieved under the previously reported methods.

  5. The role of threshold limit values in U.S. air pollution policy.

    PubMed

    Robinson, J C; Paxman, D G

    1992-01-01

    This paper analyzes the role of threshold limit values (TLVs) in national air pollution policy during the 1980s, a period in which the Environmental Protection Agency (EPA) sought to delegate to individual states the authority to evaluate and regulate airborne toxic substances. We focus on 20 carcinogens and 11 substances with non-genotoxic health effects that were regulated by local air toxics programs using TLVs. Data from EPA's National Air Toxics Information Clearinghouse indicate that maximum TLV-based Ambient Air Level guidelines (AALs) frequently exceed minimum TLV-based AALs by a factor of greater than 1,000. Cancer potency data from EPA's Integrated Risk Information System suggest significant risks remain at TLV-based AALs. Cancer risks at the median TLV-based AAL exceed 1,000 cases per million exposed persons for cadmium (1,040), nickel and its compounds (1,420), propylene oxide (1,550), coke oven emissions (1,860), benzene (2,500), arsenic and its compounds (7,300), N-nitrosodimethylamine (21,000), asbestos (21,500), and ethylene dibromide (55,000). We also summarize published studies that report non-genotoxic health effects in workers exposed at levels near the TLV for 11 substances whose AALs were based on TLVs. Contrary to the assumption frequently made by state air toxics program, TLVs cannot be taken to represent no observed effect levels (NOELs) for regulatory purposes.

  6. Investigation of mortality from cancer and other causes of death among workers employed at an east Texas chemical plant

    SciTech Connect

    Sweeney, M.H.; Beaumont, J.J.; Waxweiler, R.J.; Halperin, W.E.

    1986-01-01

    The cause-specific mortality of 2,510 males employed at an east Texas chemical plant was examined in a historical prospective study to evaluate a suspected increase in deaths from multiple myeloma and brain cancer. Potential exposures from chemicals, either used in manufacturing processes or produced during the study period 1952-1977, included the fuel additive tetraethyl lead, ethylene dibromide and dichloride, inorganic lead, and vinyl chloride monomer. Overall mortality for all workers (156 observed vs. 211.14 expected) and for workers first employed between 1952 and 1959 (131 observed vs. 167.33 expected) when tetraethyl lead was the single major product was lower than expected when compared to the United States general population. There were no significant increases in mortality from malignancies or other causes of death. The deficits may be due to the small number of total deaths, and the low power for detecting excess risk of mortality from multiple myeloma (Z1-beta = 27, alpha = .05), brain cancer (Z1-beta = 31, alpha = .05), or other rare causes of death; lack of complete workplace exposure data for production workers; and the absence of historical measurements on the extent of environmental exposure to tetraethyl lead and other chemicals.

  7. Cholinesterase in the parasitic nematode, Stephanurus dentatus. Characterization and sex dependence of a secretory cholinesterase.

    PubMed

    Rhoads, M L

    1981-09-10

    An antigenic secretory protein with cholinesterase activity was isolated from the excretory gland cells of Stephanurus dentatus and was purified by gel filtration and ion exchange chromatography. The antigenicity of the cholinesterase was demonstrated by an esterase-active immunoprecipitate formed with S. dentatus antiserum and by the ability of the antiserum to protect the enzyme from heat inactivation. The enzyme was found to be secreted by the adult nematodes during in vitro cultivation. The level of cholinesterase activity and its release from the excretory gland cells of the parasite were 27-fold greater in the male than in the female. Ninety per cent of the enzyme activity was localized in the soluble fraction of the gland cells. The molecular weight of the enzyme, estimated by sucrose density gradient centrifugation, was 100,000. Two molecular forms were separated by isoelectrofocusing, with isoelectric points of 7.0 and 6.9. At optimum substrate concentrations, the rate of hydrolysis of acetylthiocholine was 8 times greater than that of butyrylthiocholine; the Michaelis constants were 560 microM and 81 microM for acetylthiocholine and butyrylthiocholine, respectively. The enzyme exhibited substrate inhibition at substrate concentrations greater than 10 mM and was inhibited by eserine sulfate, 1,5-bis(4-allyldimethylammoniumphenyl)-pentan-3-one dibromide, Tris, and acetone. The enzyme was highly unstable in dilute protein solutions.

  8. Novel spectrophotometric method for detection and estimation of butanol in acetone-butanol-ethanol fermenter.

    PubMed

    Maiti, Sampa; Sarma, Saurabh Jyoti; Brar, Satinder Kaur; Bihan, Yann Le; Drogui, Patrick; Buelna, Gerardo; Verma, Mausam; Soccol, Carlos Ricardo

    2015-08-15

    A new, simple, rapid and selective spectrophotometric method has been developed for detection and estimation of butanol in fermentation broth. The red colored compound, produced during reduction of diquat-dibromide-monohydrate with 2-mercaptoethanol in aqueous solution at high pH (>13), becomes purple on phase transfer to butanol and gives distinct absorption at λ520nm. Estimation of butanol in the fermentation broth has been performed by salting out extraction (SOE) using saturated K3PO4 solution at high pH (>13) followed by absorbance measurement using diquat reagent. Compatibility and optimization of diquat reagent concentration for detection and estimation of butanol concentration in the fermentation broth range was verified by central composite design. A standard curve was constructed to estimate butanol in acetone-ethanol-butanol (ABE) mixture under optimized conditions. The spectrophotometric results for butanol estimation, was found to have 87.5% concordance with the data from gas chromatographic analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Opposing effects of oxidative challenge and carotenoids on antioxidant status and condition-dependent sexual signalling.

    PubMed

    Tomášek, Oldřich; Gabrielová, Barbora; Kačer, Petr; Maršík, Petr; Svobodová, Jana; Syslová, Kamila; Vinkler, Michal; Albrecht, Tomáš

    2016-03-22

    Several recent hypotheses consider oxidative stress to be a primary constraint ensuring honesty of condition-dependent carotenoid-based signalling. The key testable difference between these hypotheses is the assumed importance of carotenoids for redox homeostasis, with carotenoids being either antioxidant, pro-oxidant or unimportant. We tested the role of carotenoids in redox balance and sexual signalling by exposing adult male zebra finches (Taeniopygia guttata) to oxidative challenge (diquat dibromide) and manipulating carotenoid intake. As the current controversy over the importance of carotenoids as antioxidants could stem from the hydrophilic basis of commonly-used antioxidant assays, we used the novel measure of in vivo lipophilic antioxidant capacity. Oxidative challenge reduced beak pigmentation but elicited an increase in antioxidant capacity suggesting resource reallocation from signalling to redox homeostasis. Carotenoids counteracted the effect of oxidative challenge on lipophilic (but not hydrophilic) antioxidant capacity, thereby supporting carotenoid antioxidant function in vivo. This is inconsistent with hypotheses proposing that signalling honesty is maintained through either ROS-induced carotenoid degradation or the pro-oxidant effect of high levels of carotenoid-cleavage products acting as a physiological handicap. Our data further suggest that assessment of lipophilic antioxidant capacity is necessary to fully understand the role of redox processes in ecology and evolution.

  10. Occupational exposure and effects on the male reproductive system.

    PubMed

    Queiroz, Erika Kaltenecker Retto de; Waissmann, William

    2006-03-01

    A significant increase in the incidence of male infertility has been described in the international literature, raising questions about its causes. Part of this effect may result from synthetic toxic substances acting on the endocrine system (endocrine disruptors), many of which are routinely used in work processes. We provide a critical review of the specialized literature on work-related chemical substances capable of causing male infertility. Pesticides such as DDT, linuron, and others, heavy metals like mercury, lead, cadmium, and copper, and substances from various industrial uses and residues such as dioxins, polychlorinated biphenyls (PCBs), ethylene dibromide (EDB), phthalates, polyvinyl chloride (PVC), and ethanol are among the main endocrine disruptors that can cause male infertility. Based on the literature, gonadal dysfunction and congenital malformation are the main alterations caused by these substances in the male reproductive system. We conclude that despite the relative lack of studies on this issue, the relevance of such risk calls for further studies as well as measures to prevent workers' exposure to the various substances.

  11. Adaptive downregulation of pheomelanin-related Slc7a11 gene expression by environmentally induced oxidative stress.

    PubMed

    Galván, Ismael; Inácio, Ângela; Romero-Haro, Ana Angela; Alonso-Alvarez, Carlos

    2017-02-01

    Pheomelanin is a sulphur-containing yellow-to-reddish pigment whose synthesis consumes the main intracellular antioxidant (glutathione; GSH) and its precursor cysteine. Cysteine used for pheomelanogenesis cannot be used for antioxidant protection. We tested whether the expression of Slc7a11, the gene regulating the transport of cysteine to melanocytes for pheomelanogenesis, is environmentally influenced when cysteine/GSH are most required for antioxidant protection. We found that zebra finches Taeniopygia guttata developing pheomelanin-pigmented feathers during a 12-day exposure to the pro-oxidant diquat dibromide downregulated the expression of Slc7a11 in feather melanocytes, but not the expression of other genes that affect pheomelanogenesis by mechanisms different from cysteine transport such as MC1R and Slc45a2. Accordingly, diquat-treated birds did not suffer increased oxidative stress. This indicates that some animals have evolved an adaptive epigenetic lability that avoids damage derived from pheomelanogenesis. This mechanism should be explored in human Slc7a11 to help combat some cancer types related to cysteine consumption.

  12. Highly stable ionic-covalent cross-linked sulfonated poly(ether ether ketone) for direct methanol fuel cells

    NASA Astrophysics Data System (ADS)

    Lei, Linfeng; Zhu, Xingye; Xu, Jianfeng; Qian, Huidong; Zou, Zhiqing; Yang, Hui

    2017-05-01

    A novel ionic cross-linked sulfonated poly(ether ether ketone) containing equal content of sulfonic acid and pendant tertiary amine groups (TA-SPEEK) has been initially synthesized for the application in direct methanol fuel cells (DMFCs). By adjusting the ratio of p-xylene dibromide to tertiary amine groups of TA-SPEEK, a series of ionic-covalent cross-linked membranes (C-SPEEK-x) with tunable degree of cross-linking are prepared. Compared with the pristine membrane, the ionic and ionic-covalent cross-linked proton exchange membranes (PEMs) exhibit reduced methanol permeability and improved mechanical properties, dimensional and oxidative stability. The proton conductivity and methanol selectivity of protonated TA-SPEEK and C-SPEEK-x at 25 °C is up to 0.109 S cm-1 and 3.88 × 105 S s cm-3, respectively, which are higher than that of Nafion 115. The DMFC incorporating C-SPEEK-25 exhibits a maximum power density as high as 35.3 mW cm-2 with 4 M MeOH at 25 °C (31.8 mW cm-2 for Nafion 115). Due to the highly oxidative stability of the membrane, no obvious performance degradation of the DMFC is observed after more than 400 h operation, indicating such cost-effective ionic-covalent cross-linked membranes have substantial potential as alternative PEMs for DMFC applications.

  13. DFT investigation of the mecahanism and stereochemistry of electrophilic transannular addition reaction of bromine to tricyclo[4.2.2.02,5]deca-3,7-diene.

    PubMed

    Abbasoglu, Rza; Misir, Miraç Nedim

    2012-03-01

    Full geometric optimization of tricyclo[4.2.2.02,5]deca-3,7-diene (TDD) has been done by DFT/B3LYP methods and the structure of the molecule was investigated. Cyclobuten double bond (I) of molecule is syn pyramidalized, and bicyclookten double bond (II) is also exo pyramidalized. The double bond (I) is more pyramidalized than the double bond (II) and it has higher reactivity. The TDD-Br2 system has been investigated by B3LYP/6-311++G(d,p) method and their stable configurations have been determined. The cationic intermediates and products obtained as a result of the addition reaction has been studied using B3LYP/6-311G(d,p) and B3LYP/6-311++G(d,p) methods. Bridged bromonium cation is more stable than U-type cation. Considering that the bridged cation does not isomerize to the less stable U-type cation, it is not possible for the U-type product to be obtained in the reaction. The bridged bromonium cation transformed into the more stable N-type cation and the N-type product was obtained via this cation. The thermodynamic stability of the anti, exo and anti, endo isomers of N-type dibromide molecule were almost identical. N-type product is 11.759 kcal mol more stable than U-type product.

  14. Conventional Study on Novel Dicationic Ionic Liquid Inclusion with β-Cyclodextrin

    PubMed Central

    Mohamad, Sharifah; Surikumaran, Hemavathy; Raoov, Muggundha; Marimuthu, Tilagam; Chandrasekaram, Kumuthini; Subramaniam, Puvaneswary

    2011-01-01

    This study focuses on the synthesis and characterization of the inclusion complex of β-Cyclodextrin (β-CD) with dicationic ionic liquid, 3,3′-(1,4-Phenylenebis [methylene]) bis(1-methyl-1H-imidazol-3-ium) di(bromide) (PhenmimBr). The inclusion complex was prepared at room temperature utilizing conventional kneading technique. Proton (1H) NMR and 2D (1H–1H) COSY NMR were the primary characterization tools employed to verify the formation of the inclusion complex. COSY spectra showed strong correlations between protons of imidazolium and protons of β-CD which indicates that the imidazolium ring of PhenmimBr has entered the cavity of β-CD. UV absorption indicated that β-CD reacts with PhenmimBr to form a 2:1 β-CD-PhenmimBr complex with an apparent formation constant of 2.61 × 105 mol&−2 L2. Other characterization studies such as UV, FT-IR, XRD, TGA, DSC and SEM studies were also used to further support the formation of the β-CD-PhenmimBr inclusion complex. PMID:22016662

  15. Electrochemistry and electrocatalysis with vitamin B sub 12 in an AOT water-in-oil microemulsion

    SciTech Connect

    Owlia, Azita; Wang, Zhenghao; Rusling, J.F. )

    1989-07-05

    Vitamin B{sub 12a} solubilized in water pools of highly resistive water-in-oil (w/o) microemulsions of 0.2 M Aerosol OT (AOT, bis(2-ethylhexyl) sulfosuccinate)/4 M water/isooctane gave separate reductions of base-on cob(III)alamine to base-on cob(II)alamine (E{sub 1/2} = {minus}0.03 V vs SCE) and base-on cob(II)alamine to base-off cob(I)alamine (E{sub 1/2} = {minus} 0.87 V). Diffusion coefficients suggested that vitamin B{sub 12} induces the formation of surfactant aggregates in w/o microemulsions that are larger than in solute-free systems. Relative reactivities toward reductions of three oil-soluble alkyl vicinal dihalides by electrochemically generated cob(I) alamine were modified in the microemulsion compared to isotropic water-acetonitrile. Changes in relative reactivity are not explained by simple partition of vicinal dibromides between isooctane and water and suggest specific interactions with surfactant aggregates or significant reaction in the bulk isooctane phase.

  16. Ryanodine receptors are expressed in epidermal keratinocytes and associated with keratinocyte differentiation and epidermal permeability barrier homeostasis.

    PubMed

    Denda, Sumiko; Kumamoto, Junichi; Takei, Kentaro; Tsutsumi, Moe; Aoki, Hirofumi; Denda, Mitsuhiro

    2012-01-01

    Ryanodine receptors (RyRs) have an important role as calcium channels in the regulation of intracellular calcium levels in the nervous system and muscle. In the present study, we investigated the expression of RyR in human epidermis. Immunohistochemical studies and reverse transcription-PCR indicated the expression of RyR type 1, 2, and 3 proteins in epidermal keratinocytes. The expression level of each RyR subtype was higher in differentiating keratinocytes than in proliferative cells. We also demonstrated the functional expression of RyR by calcium imaging. In cultured human keratinocytes, application of the RyR agonist 4-chloro-m-cresol (CMC) induced elevation of the intracellular calcium concentration, and co-application of the RyR antagonist 1,1'-diheptyl-4,4'-bipyridinium dibromide (DHBP) blocked the elevation. Application of CMC accelerated keratinocyte differentiation in vitro. On the other hand, topical application of CMC after tape-stripping of hairless mouse skin delayed barrier recovery, whereas application of an RyR antagonist, dantrolene or DHBP, accelerated the barrier recovery. These results suggest that RyR expressed in epidermal keratinocytes is associated with both differentiation of keratinocytes and epidermal barrier homeostasis.

  17. Adaptor Protein Complex 2–Mediated Endocytosis Is Crucial for Male Reproductive Organ Development in Arabidopsis[W

    PubMed Central

    Kim, Soo Youn; Xu, Zheng-Yi; Song, Kyungyoung; Kim, Dae Heon; Kang, Hyangju; Reichardt, Ilka; Sohn, Eun Ju; Friml, Jiří; Juergens, Gerd; Hwang, Inhwan

    2013-01-01

    Fertilization in flowering plants requires the temporal and spatial coordination of many developmental processes, including pollen production, anther dehiscence, ovule production, and pollen tube elongation. However, it remains elusive as to how this coordination occurs during reproduction. Here, we present evidence that endocytosis, involving heterotetrameric adaptor protein complex 2 (AP-2), plays a crucial role in fertilization. An Arabidopsis thaliana mutant ap2m displays multiple defects in pollen production and viability, as well as elongation of staminal filaments and pollen tubes, all of which are pivotal processes needed for fertilization. Of these abnormalities, the defects in elongation of staminal filaments and pollen tubes were partially rescued by exogenous auxin. Moreover, DR5rev:GFP (for green fluorescent protein) expression was greatly reduced in filaments and anthers in ap2m mutant plants. At the cellular level, ap2m mutants displayed defects in both endocytosis of N-(3-triethylammonium-propyl)-4-(4-diethylaminophenylhexatrienyl) pyridinium dibromide, a lypophilic dye used as an endocytosis marker, and polar localization of auxin-efflux carrier PIN FORMED2 (PIN2) in the stamen filaments. Moreover, these defects were phenocopied by treatment with Tyrphostin A23, an inhibitor of endocytosis. Based on these results, we propose that AP-2–dependent endocytosis plays a crucial role in coordinating the multiple developmental aspects of male reproductive organs by modulating cellular auxin level through the regulation of the amount and polarity of PINs. PMID:23975898

  18. Occupational cancer in Spain.

    PubMed Central

    González, C A; Agudo, A

    1999-01-01

    The knowledge of specific problems of occupational cancer in Spain is scarce. The environment of the workplace has improved over the last few years after a long period distinguished by bad working conditions, incomplete legislation, and insufficient safety measures and control. It has been estimated that 3,083,479 workers (25.4% of employees) were exposed to carcinogens. The most common occupational exposures to carcinogenic agents were solar radiation, environmental tobacco smoke, silica, and wood dust. The highest number of employees were exposed to silica crystalline (404,729), diesel engine exhaust (274,321), rubber products (99,804), benzene (89,932), ethylene dibromide (81,336), agents used in furniture and cabinet making (72,068), and formaldehyde (71,189). The percentage of total cancer deaths attributed to occupational exposure was 4% (6% in men, 0.9% in women). Compared with other European countries, the incidence of lung cancer and leukemia in Spain are one of the lowest, but it is rapidly increasing. The incidence of urinary bladder and larynx cancer, on the contrary, are one of the highest. Few studies on occupational cancer have been conducted in Spain. The main problems are the availability of death certificates and the quality of the information on occupation in mortality of statistics. It is necessary to improve methods of assessment of exposures using expert hygienists and biologic markers of exposure and diseases. Reduction of cancer by limiting or avoiding exposure to known occupational carcinogens is still necessary. PMID:10350510

  19. Ratios of biliary glutathione disulfide (GSSG) to glutathione (GSH): a potential index to screen drug-induced hepatic oxidative stress in rats and mice.

    PubMed

    Cao, Lei; Waldon, Daniel; Teffera, Yohannes; Roberts, John; Wells, Mary; Langley, Meghan; Zhao, Zhiyang

    2013-03-01

    Hepatotoxicity of drug candidates is one of the major concerns in drug screening in early drug discovery. Detection of hepatic oxidative stress can be an early indicator of hepatotoxicity and benefits drug selection. The glutathione (GSH) and glutathione disulfide (GSSG) pair, as one of the major intracellular redox regulating couples, plays an important role in protecting cells from oxidative stress that is caused by imbalance between prooxidants and antioxidants. The quantitative determination of the GSSG/GSH ratios and the concentrations of GSH and GSSG have been used to indicate oxidative stress in cells and tissues. In this study, we tested the possibility of using the biliary GSSG/GSH ratios as a biomarker to reflect hepatic oxidative stress and drug toxicity. Four compounds that are known to alter GSH and GSSG levels were tested in this study. Diquat (diquat dibromide monohydrate) and acetaminophen were administered to rats. Paraquat and tert-butyl hydroperoxide were administered to mice to induce changes of biliary GSH and GSSG. The biliary GSH and GSSG were quantified using calibration curves prepared with artificial bile to account for any bile matrix effect in the LC-MS analysis and to avoid the interference of endogenous GSH and GSSG. With four examples (in rats and mice) of drug-induced changes in the kinetics of the biliary GSSG/GSH ratios, this study showed the potential for developing an exposure response index based on biliary GSSG/GSH ratios for predicting hepatic oxidative stress.

  20. Evaluation of diquat against an acute experimental infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus (Rafinesque).

    PubMed

    Darwish, A M; Mitchell, A J

    2009-05-01

    A trial was performed to evaluate the efficacy of diquat (6,7-dihydrodipyrido[1,2-a:2',1'-c]pyrazinediium dibromide) against an acute experimental infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus. Diquat is an Environmental Protection Agency-approved herbicide and has the potential to be legally and practically used against columnaris. Channel catfish were challenged, by cutaneous abrasion, and waterborne exposure to F. columnare and treated once at 22-h post-challenge with 2.5, 5.0, 10.0 and 15 mg L(-1) of diquat active ingredient for 6 h. At the conclusion of the trial, 21-day post-challenge, diquat at 5.0, 10.0 and 15 mg L(-1) significantly (P < 0.05) reduced the mortality of infected fish from 95% in the challenged non-treated fish to 68%, 59% and 49%, respectively. In vitro, the minimum inhibitory concentration (MIC) of 23 isolates of F. columnare was assayed. The majority of the isolates had an MIC value of 5 microg mL(-1) (15 of the 23 isolates). Infected fish exhibited acute clinical signs similar to a natural infection. The skin had severe ulcerative necrotizing dermatitis and the muscles had severe necrotizing myositis. The gills had severe multifocal necrotizing branchitis. The results demonstrate that diquat would reduce mortalities caused by an acute columnaris infection.

  1. Reduction of 1,2-dibromoethane in the presence of zero-valent iron

    SciTech Connect

    Rajagopal, V.K.; Burris, D.R.

    1999-08-01

    The degradation reaction of 1,2-dibromoethane (ethylene dibromide or EDB) in water was studied in the presence of zero-valent iron (acid-cleaned, cast iron) in well-mixed batch aqueous systems. The observed products were ethylene and bromide ions. Carbon and bromine mass recoveries of >95% were obtained. Bromoethane and vinyl bromide were not observed. The reduction rates of bromoethane and vinyl bromide with iron indicate that they should have been observed if they were significant reaction intermediates for EDB. The results indicate that reductive {beta}-elimination may be the dominant reaction pathway. Reaction kinetics are rapid and pseudo-first order. The activation energy was determined to be 50 kJ/mol, indicating that the reaction rate may not be aqueous phase diffusion controlled but rather controlled by the chemical reaction rate on the iron surface. Metallic iron may be a suitable treatment approach for EDB-contaminated groundwater in above-ground, as well as in situ applications, due to rapid kinetics and nontoxic products.

  2. Efficient gene transfection using novel cationic polymers poly(hydroxyalkylene imines).

    PubMed

    Zaliauskiene, Lolita; Bernadisiute, Ula; Vareikis, Ausvydas; Makuska, Ricardas; Volungeviciene, Ieva; Petuskaite, Agne; Riauba, Laurynas; Lagunavicius, Arunas; Zigmantas, Sarunas

    2010-09-15

    A series of novel cationic polymers poly(hydroxyalkylene imines) were synthesized and tested for their ability to transfect cells in vitro and in vivo. Poly(hydroxyalkylene imines), in particular, poly(2-hydroxypropylene imine) (pHP), poly(2-hydroxypropylene imine ethylene imine) (pHPE), and poly(hydroxypropylene imine propylene imine) (pHPP) were synthesized by polycondensation reaction from 1,3-diamino-2-propanol and the appropriate dibromide. Electron microscopic examination demonstrated that the resulting polymers condensed DNA into toroid shape complexes of 100-150 nm in size. Transfection studies showed that all three polymers were able to deliver genetic material into the cell, with pHP being superior to pHPP and pHPE. pHP acted as an efficient gene delivery agent in a variety of different cell lines and outcompeted most of the widely used polymer or lipid based transfection reagents. Intravenous administration of pHP-DNA polyplexes in mice followed by the reporter gene analysis showed that the reagent was suitable for in vivo applications. In summary, the results indicate that pHP is a new efficient reagent for gene delivery in vitro and in vivo.

  3. Photochemical approach to functionalized benzobicyclo[3.2.1]octene structures via fused oxazoline derivatives from 4- and 5-(o-vinylstyryl)oxazoles

    PubMed Central

    Šagud, Ivana; Božić, Simona; Marinić, Željko

    2014-01-01

    Summary Novel cis/trans-4- and cis/trans-5-(2-vinylstyryl)oxazoles have been synthesized by Wittig reactions from the diphosphonium salt of α,α’-o-xylene dibromide, formaldehyde and 4- and 5-oxazolecarbaldehydes, respectively. In contrast, trans-5-(2-vinylstyryl)oxazole has been synthesized by the van Leusen reaction from trans-3-(2-vinylphenyl)acrylaldehyde which is prepared from o-vinylbenzaldehyde and (formylmethylene)triphenylphosphorane. The 4- and 5-(2-vinylstyryl)oxazoles afford, by photochemical intramolecular cycloaddition, diverse fused oxazoline-benzobicyclo[3.2.1]octadienes, which are identified and characterized by spectroscopic methods. The photoproducts formed are relatively unstable and spontaneously or on silica gel undergo oxazoline ring opening followed by formation of formiato- or formamido-benzobicyclo[3.2.1]octenone derivatives. On irradiation of 4-(2-vinylstyryl)oxazole small quantities of electrocyclization product, 4-(1,2-dihydronaphthalen-2-yl)oxazole, are isolated and spectroscopically characterized. PMID:25246981

  4. Isolation of yeast mutants defective for localization of vacuolar vital dyes

    PubMed Central

    Zheng, Bing; Wu, Jennifer N.; Schober, Wendy; Lewis, Dorothy E.; Vida, Thomas

    1998-01-01

    An application of flow cytometric sorting is used for isolation of Saccharomyces cerevisiae mutants that mislocalize vacuolar vital dyes. This screen is based on the ability of a lipophilic styryl compound, N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide (FM4–64), to label endocytic intermediates from the plasma membrane to the vacuole membrane at 15°C. Cells stained at 15°C for both FM4–64 and carboxydichlorofluorescein diacetate (a vacuolar luminal vital stain), had a pronounced shift in red/green fluorescence from cells stained at 30° or 38°C. Flow cytometric selection based on this characteristic shift allowed the isolation of 16 mutants. These comprised 12 complementation groups, which we have designated SVL for styryl dye vacuolar localization. These groups were put into three classes. Class I mutants contain very large vacuoles; class II mutants have very fragmented vacuoles; and class III mutants show the strongest svl phenotype with punctate/diffuse FM4–64 staining. Limited genetic overlap was observed with previously isolated mutants, namely svl2/vps41, svl6/vps16, and svl7/fab1. The remaining svl mutants appear to represent novel genes, two of which showed temperature-sensitive vacuole staining morphology. Another mutant, svl8, displayed defects in uptake and sorting of phosphatidylcholine and phosphatidylethanolamine. Our flow cytometric strategy may be useful for isolation of other mutants where mislocalization of fluorescent compounds can be detected. PMID:9751732

  5. Trade-off between carotenoid-based sexual ornamentation and sperm resistance to oxidative challenge.

    PubMed

    Tomášek, Oldřich; Albrechtová, Jana; Němcová, Martina; Opatová, Pavlína; Albrecht, Tomáš

    2017-01-25

    It has been hypothesized that carotenoid-based sexual ornamentation signals male fertility and sperm competitive ability as both ornamentation and sperm traits may be co-affected by oxidative stress, resulting in positive covariation (the 'redox-based phenotype-linked fertility hypothesis'; redox-based PLFH). On the other hand, the 'sperm competition theory' (SCT) predicts a trade-off between precopulatory and postcopulatory traits. Here, we manipulate oxidative status (using diquat dibromide) and carotenoid availability in adult zebra finch (Taeniopygia guttata) males in order to test whether carotenoid-based beak ornamentation signals, or is traded off against, sperm resistance to oxidative challenge. Initial beak colouration, but not its change during the experiment, was associated with effect of oxidative challenge on sperm velocity, such that more intense colouration predicted an increase in sperm velocity under control conditions but a decline under oxidative challenge. This suggests a long-term trade-off between ornament expression and sperm resistance to oxidative challenge. Shortening of the sperm midpiece following oxidative challenge further suggests that redox homeostasis may constrain sperm morphometry. Carotenoid supplementation resulted in fewer sperm abnormalities but had no effect on other sperm traits. Overall, our data challenge the redox-based PLFH, partially support the SCT and highlight the importance of carotenoids for normal sperm morphology.

  6. Readily releasable vesicles recycle at the active zone of hippocampal synapses.

    PubMed

    Schikorski, Thomas

    2014-04-08

    During the synaptic vesicle cycle, synaptic vesicles fuse with the plasma membrane and recycle for repeated exo/endocytic events. By using activity-dependent N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino) styryl) pyridinium dibromide dye uptake combined with fast (<1 s) microwave-assisted fixation followed by photoconversion and ultrastructural 3D analysis, we tracked endocytic vesicles over time, "frame by frame." The first retrieved synaptic vesicles appeared 4 s after stimulation, and these endocytic vesicles were located just above the active zone. Second, the retrieved vesicles did not show any sign of a protein coat, and coated pits were not detected. Between 10 and 30 s, large labeled vesicles appeared that had up to 5 times the size of an individual synaptic vesicle. Starting at around 20 s, these large labeled vesicles decreased in number in favor of labeled synaptic vesicles, and after 30 s, labeled vesicles redocked at the active zone. The data suggest that readily releasable vesicles are retrieved as noncoated vesicles at the active zone.

  7. Photochemical approach to functionalized benzobicyclo[3.2.1]octene structures via fused oxazoline derivatives from 4- and 5-(o-vinylstyryl)oxazoles.

    PubMed

    Sagud, Ivana; Božić, Simona; Marinić, Zeljko; Sindler-Kulyk, Marija

    2014-01-01

    Novel cis/trans-4- and cis/trans-5-(2-vinylstyryl)oxazoles have been synthesized by Wittig reactions from the diphosphonium salt of α,α'-o-xylene dibromide, formaldehyde and 4- and 5-oxazolecarbaldehydes, respectively. In contrast, trans-5-(2-vinylstyryl)oxazole has been synthesized by the van Leusen reaction from trans-3-(2-vinylphenyl)acrylaldehyde which is prepared from o-vinylbenzaldehyde and (formylmethylene)triphenylphosphorane. The 4- and 5-(2-vinylstyryl)oxazoles afford, by photochemical intramolecular cycloaddition, diverse fused oxazoline-benzobicyclo[3.2.1]octadienes, which are identified and characterized by spectroscopic methods. The photoproducts formed are relatively unstable and spontaneously or on silica gel undergo oxazoline ring opening followed by formation of formiato- or formamido-benzobicyclo[3.2.1]octenone derivatives. On irradiation of 4-(2-vinylstyryl)oxazole small quantities of electrocyclization product, 4-(1,2-dihydronaphthalen-2-yl)oxazole, are isolated and spectroscopically characterized.

  8. Readily releasable vesicles recycle at the active zone of hippocampal synapses

    PubMed Central

    Schikorski, Thomas

    2014-01-01

    During the synaptic vesicle cycle, synaptic vesicles fuse with the plasma membrane and recycle for repeated exo/endocytic events. By using activity-dependent N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino) styryl) pyridinium dibromide dye uptake combined with fast (<1 s) microwave-assisted fixation followed by photoconversion and ultrastructural 3D analysis, we tracked endocytic vesicles over time, “frame by frame.” The first retrieved synaptic vesicles appeared 4 s after stimulation, and these endocytic vesicles were located just above the active zone. Second, the retrieved vesicles did not show any sign of a protein coat, and coated pits were not detected. Between 10 and 30 s, large labeled vesicles appeared that had up to 5 times the size of an individual synaptic vesicle. Starting at around 20 s, these large labeled vesicles decreased in number in favor of labeled synaptic vesicles, and after 30 s, labeled vesicles redocked at the active zone. The data suggest that readily releasable vesicles are retrieved as noncoated vesicles at the active zone. PMID:24706824

  9. Peroxisome Degradation by Microautophagy in Pichia pastoris: Identification of Specific Steps and Morphological Intermediates

    PubMed Central

    Sakai, Yasuyoshi; Koller, Antonius; Rangell, Linda K.; Keller, Gilbert A.; Subramani, Suresh

    1998-01-01

    We used the dye N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenylhexatrienyl) pyridinium dibromide (FM4-64) and a fusion protein, consisting of the green fluorescent protein appended to the peroxisomal targeting signal, Ser-Lys-Leu (SKL), to label the vacuolar membrane and the peroxisomal matrix, respectively, in living Pichia pastoris cells and followed by fluorescence microscopy the morphological and kinetic intermediates in the vacuolar degradation of peroxisomes by microautophagy and macroautophagy. Structures corresponding to the intermediates were also identified by electron microscopy. The kinetics of appearance and disappearance of these intermediates is consistent with a precursor–product relationship between intermediates, which form the basis of a model for microautophagy. Inhibitors affecting different steps of microautophagy did not impair peroxisome delivery to the vacuole via macroautophagy, although inhibition of vacuolar proteases affected the final vacuolar degradation of green fluorescent protein (S65T mutant version [GFP])-SKL via both autophagic pathways. P. pastoris mutants defective in peroxisome microautophagy (pag mutants) were isolated and characterized for the presence or absence of the intermediates. These mutants, comprising 6 complementation groups, support the model for microautophagy. Our studies indicate that the microautophagic degradation of peroxisomes proceeds via specific intermediates, whose generation and/or processing is controlled by PAG gene products, and shed light on the poorly understood phenomenon of peroxisome homeostasis. PMID:9566964

  10. Hydrogen-bonding motifs and thermotropic polymorphism in redetermined halide salts of hexamethylenediamine.

    PubMed

    van Blerk, Charmaine; Kruger, Gert J

    2008-10-01

    The redetermined crystal structures of hexane-1,6-diammonium dichloride, C(6)H(18)N(2)(2+) x 2 Cl(-), (I), hexane-1,6-diammonium dibromide, C(6)H(18)N(2)(2+) x 2 Br(-), (II), and hexane-1,6-diammonium diiodide, C(6)H(18)N(2)(2+) x 2 I(-), (III), are described, focusing on their hydrogen-bonding motifs. The chloride and bromide salts are isomorphous, with both demonstrating a small deviation from planarity [173.89 (10) and 173.0 (2) degrees, respectively] in the central C-C-C-C torsion angle of the hydrocarbon backbone. The chloride and bromide salts also show marked similarities in their hydrogen-bonding interactions, with subtle differences evident in the hydrogen-bond lengths reported. Bifurcated interactions are exhibited between the N-donor atoms and the halide acceptors in the chloride and bromide salts. The iodide salt is very different in molecular structure, packing and intermolecular interactions. The hydrocarbon chain of the iodide straddles an inversion centre and the ammonium groups on the diammonium cation of the iodide salt are offset from the planar hydrocarbon backbone by a torsion angle of 69.6 (4) degrees. All three salts exhibit thermotropic polymorphism, as is evident from differential scanning calorimetry analysis and variable-temperature powder X-ray diffraction studies.

  11. A common mechanism for coenzyme cobalamin-dependent reductive dehalogenases.

    PubMed

    Johannissen, Linus O; Leys, David; Hay, Sam

    2017-02-22

    Distinct mechanisms have been proposed for the biological dehalogenation catalyzed by cobalamin-dependent enzymes, with two recent crystallographic studies suggesting different mechanisms based on the observed interaction between the organohalide substrate and cobalamin. In one case, involving an aromatic dibromide substrate in NpRdhA, a novel Co(II)-Br interaction was observed using EPR, suggesting a mechanism involving a [CoXR] adduct. However, in the case of trichloroethylene in PceA, a significantly longer Co-Cl distance was observed in X-ray crystal structures, suggesting a dissociative electron transfer mechanism. Subsequent DFT models of these reactions have not reproduced these differences in binding modes. Here, we have performed molecular docking and DFT calculations to investigate and compare the interaction between different organohalides and cobalamin in both NpRdhA and PceA. In each case, despite differences in binding in the Co(II) state, the reaction likely proceeds via formation of a [CoXR] adduct in the Co(I) state that weakens the breaking carbon-halide bond, suggesting this could be a general mechanism for cobalamin-dependent dehalogenation.

  12. Rayleigh, Ramsay, Rutherford and Raman--their connections with, and contributions to, the discovery of the Raman effect.

    PubMed

    Clark, Robin J H

    2013-02-21

    The key contributions of the four great Nobel Laureates - Lord Rayleigh, Sir William Ramsay, Lord Rutherford and Sir Chandrasekhara Raman - to the understanding of light scattering, to the identification and classification of the rare gases, and to the discovery in 1928 of the Raman effect are outlined. The interactions between these scientists are explored, in particular those of Rayleigh with Ramsay (in establishing the physics and chemistry of the rare gases), Ramsay with Rutherford (on studies of the radioactivity of radium dibromide and on the discovery of radon and its position in the periodic table), and Rutherford with Raman (in supporting Raman's career via the Royal Society and as a nominee for the Nobel Prize). The resilience and dedication of these scientific pioneers is emphasised, noting in particular that Rutherford and Raman emerged with success from unlikely backgrounds and from countries far removed from the then centres of scientific excellence. Key developments from 1928 onwards in the light sources used for the excitation of Raman spectra and in the detectors of Raman scattered radiation are outlined. Attention is drawn to the mounting number of scientific areas which continue to be opened up by Raman microscopy and many other derived techniques such as SERS, TERS, etc.

  13. Molecular binding behavior of water-soluble calix[4]arenes with asymmetric 4,4'-bipyridinium guests in aqueous solution: regioselective recognition or not?

    PubMed

    Wang, Kui; Cui, Jian-Hua; Xing, Si-Yang; Dou, Hong-Xi

    2016-11-22

    The molecular binding behavior of water-soluble calix[4]arenes (p-sulfonatocalix[4]arene (SC4A) and p-sulfonatothiacalix[4]arene (STC4A)) with two asymmetric 4,4'-bipyridinium guests (N-methyl-N'-adamantane carbomethyl-4,4'-bipyridinium dibromide (MVAd(2+)) and N-methyl-N'-(naphthalen-2-ylmethyl)-4,4'-bipyridinium bromide iodide (MVNp(2+))) was systematically studied using NMR spectroscopy and microcalorimetry in a neutral aqueous solution. Either the methyl group or the adamantane moiety in MVAd(2+) could enter into the SC4A and STC4A cavities, without regioselectivity. The STC4A cavity can also accommodate MVNp(2+), either through incorporation of the methyl group or the naphthalene moiety, without regioselectivity. However, we were surprised to find that MVNp(2+) could only be included within the SC4A cavity through incorporation of the methyl group, with regioselectivity, which is rare for a flexible host. Furthermore, both SC4A and STC4A can form stable inclusion complexes with the two investigated asymmetric 4,4'-bipyridinium guests, driven by very favorable enthalpy changes, and the thermodynamic origins of the host selectivities for MVAd(2+) and MVNp(2+) can be well explained through their binding modes. The finding of this novel regioselective recognition is promising for potential applications in the development of more sophisticated biomimetic materials.

  14. Matching kinetics of synaptic vesicle recycling and enhanced neurotransmitter influx by Ca2+ in brain plasma membrane vesicles.

    PubMed

    Kovács, I; Szárics, E; Nyitrai, G; Blandl, T; Kardos, J

    1998-11-01

    Using native plasma membrane vesicle suspensions from the rat cerebral cortex under conditions designed to alter intravesicular [Ca2+], we found that Ca2+ induced 47 +/- 5% more influx of [3H]GABA, [3H]D-aspartate and [3H]glycine at 37 degrees C with half-times 1.7 +/- 0.5, 1.3 +/- 0.4 and 1.3 +/- 0.4 min, respectively. We labelled GABA transporter sites with the uptake inhibitor, [3H]-(R,S)-N-[4,4-bis(3-methyl-2-thienyl)but-3-en-1-yl]nipecotic acid and found that Ca2+ induced a partial dissociation of the bound inhibitor from GABA transporter sites with a similar half-time. By means of rapid kinetic techniques applied to native plasma membrane vesicle suspensions, containing synaptic vesicles stained with the amphipathic fluorescent styryl membrane probe N-(3-triethylammoniumpropyl)-4-[4-(dibutylamino)styryl]pyrid inium dibromide, we have measured the progress of the release and reuptake of synaptic vesicles in response to Ca2+ and high-[K+] depolarization in the 0.0004-100 s range of time. Synaptic vesicle exocytosis, strongly influenced by external [Ca2+], appeared with the kinetics accelerated by depolarization. These results are consistent with the potential involvement of Ca2+ in taking low-affinity transporters to the plasma membrane surface via exocytosis.

  15. Use of X-Chromosome Inactivation Pattern to Analyze the Clonality of 14 Female Cases of Kaposi Sarcoma

    PubMed Central

    Yuan, Ding; XiuJuan, Wu; Yan, Zhang; JunQin, Liang; Fang, Xiang; Shirong, Yu; Xiaojing, Kang; Yanyan, Feng; Weidong, Wu; Dong, Luo; Qingli, Lu; DeZhi, Zhang; XiongMing, Pu

    2015-01-01

    Background Kaposi sarcoma (KS) has features of both neoplastic growth and hyperplastic proliferation. It is the most common tumor seen in patients with HIV infection. Whether KS is a real tumor or a benign hyperplastic disease is not known. Material/Methods Tissues from KS and cutaneous hemangioma lesion DNA were extracted, and then digested with methylation-sensitive restriction endonuclease HpaII. Human androgen receptor gene (HUMARA) was amplified with PCR method and the product was separated on 10% denaturing polyacrylamide gels and stained with ethylene dibromide (EB) to show the polymorphism of HUMARA. Phosphoglycerate kinase (PGK) was amplified and the product was digested by BStXI, agarose gel and EB stained to show the polymorphism of PGK. Finally, we analyzed the clonality of KS. Results In the 14 patients with KS, heterozygosity of the HUMARA gene was observed in 12 (85.7%) cases. Loss of heterozygosity of HUMARA gene on X-chromosome (without HpaII digestion there were 2 bands, after HpaII digestion there were just 1 of the bands), representing monoclonal origin, was present in 11 cases of Kaposi sarcoma. Heterozygosity of the PGK gene was observed in 5 (35.7%) cases, which all represent monoclonal origin. There was no significant difference according to country, stage, or HIV and HHV-8 (P>0.05). Conclusions The current findings suggest that Kaposi sarcoma is a clonal neoplasm, not a reactive proliferation. PMID:26076995

  16. Use of X-Chromosome Inactivation Pattern to Analyze the Clonality of 14 Female Cases of Kaposi Sarcoma.

    PubMed

    Yuan, Ding; XiuJuan, Wu; Yan, Zhang; JunQin, Liang; Fang, Xiang; Shirong, Yu; Xiaojing, Kang; Yanyan, Feng; Weidong, Wu; Dong, Luo; Qingli, Lu; DeZhi, Zhang; XiongMing, Pu

    2015-06-16

    Kaposi sarcoma (KS) has features of both neoplastic growth and hyperplastic proliferation. It is the most common tumor seen in patients with HIV infection. Whether KS is a real tumor or a benign hyperplastic disease is not known. Tissues from KS and cutaneous hemangioma lesion DNA were extracted, and then digested with methylation-sensitive restriction endonuclease HpaII. Human androgen receptor gene (HUMARA) was amplified with PCR method and the product was separated on 10% denaturing polyacrylamide gels and stained with ethylene dibromide (EB) to show the polymorphism of HUMARA. Phosphoglycerate kinase (PGK) was amplified and the product was digested by BStXI, agarose gel and EB stained to show the polymorphism of PGK. Finally, we analyzed the clonality of KS. In the 14 patients with KS, heterozygosity of the HUMARA gene was observed in 12 (85.7%) cases. Loss of heterozygosity of HUMARA gene on X-chromosome (without HpaII digestion there were 2 bands, after HpaII digestion there were just 1 of the bands), representing monoclonal origin, was present in 11 cases of Kaposi sarcoma. Heterozygosity of the PGK gene was observed in 5 (35.7%) cases, which all represent monoclonal origin. There was no significant difference according to country, stage, or HIV and HHV-8 (P>0.05). The current findings suggest that Kaposi sarcoma is a clonal neoplasm, not a reactive proliferation.

  17. A class Vb chitin synthase in Colletotrichum graminicola is localized in the growing tips of multiple cell types, in nascent septa, and during septum conversion to an end wall after hyphal breakage.

    PubMed

    Amnuaykanjanasin, A; Epstein, L

    2006-05-01

    Previous complementation of a chitin synthase class Vb null mutant (Colletotrichum graminicola chsA) indicated that the encoded protein is responsible for approximately 30% of the conidial chitin, is essential for conidial wall strength in media with high water potential, and contributes to strength of hyphal tips. We complemented a chsA null mutant with chsA fused to the green-fluorescent protein (sgfp) gene driven by a heterologous constitutively expressed promoter. Comparisons of the strain with the ectopic chsA-sgfp to the wild type indicated that ChsA-sGFP serves the same biological functions as ChsA in that like the wild type, the chsADelta chsA::sgfp (EC) had conidia that did not explode and hyphal tips that did not swell. Confocal microscopy of ChsA-sGFP (EC) cells stained with the membrane stain FM 4-64 (N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide) indicated that ChsA is localized in the plasma membrane of the following: growing apices of hyphal branches, conidiophores, and falcate and oval conidia; in nascent septa; and in septa that are being converted to an end wall after hyphal breakage. The data support the hypothesis that chsA either directly or indirectly encodes the information for its localization, that ChsA is localized in the plasma membrane, and that the class Vb enzyme produces chitin synthase in multiple cells and after wall breakage.

  18. Amplified fluorescent sensing of DNA using graphene oxide and a conjugated cationic polymer.

    PubMed

    Xing, Xiao-Jing; Liu, Xue-Guo; He, Yue; Lin, Yi; Zhang, Cui-Ling; Tang, Hong-Wu; Pang, Dai-Wen

    2013-01-14

    We explore the interactions between a fluorescein (FAM)-labeled single-stranded DNA (P), graphene oxide (GO), and a cationic conjugated polymer, poly [(9,9-bis(6'-N,N,N-trimethylammonium)hexyl)-fluorenylene phenylene dibromide] (PFP). It is found that the fluorescence change of P-GO-PFP system is dependent on the addition order of P and PFP. When adding PFP into P/GO complex, the fluorescence resonance energy transfer (FRET) from PFP to P is inefficient. If P is added to PFP/GO complex, efficient FRET is obtained. This may be attributed to the equal binding ability for P and PFP to GO. The results of time-resolved fluorescence and fluorescence anisotropy support the different fluorescent response under different addition order of P and PFP to GO. Based on the above phenomenon, we demonstrate a method to reduce the high background signal of a traditional PFP-based DNA sensor by introducing GO. In comparison to the use of single PFP, the combination of PFP with GO-based method shows enhanced sensitivity with a detection limit as low as 40 pM for target DNA detection.

  19. Genotoxicity testing of five herbicides in the Drosophila wing spot test.

    PubMed

    Kaya, B; Yanikoglu, A; Creus, A; Marcos, R

    2000-02-16

    Four triazine herbicides: amitrole, metribuzin, prometryn and terbutryn, and the bipyridal compound diquat dibromide have been evaluated for genotoxicity in the wing somatic mutation and recombination test of Drosophila melanogaster, following standard procedures. Third-instar larvae trans-heterozygous for the third chromosome recessive markers multiple wing hairs (mwh) and flare-3 (flr(3)) were chronically fed with different concentrations of the test compounds. Feeding ended with pupation of the surviving larvae. Genetic changes induced in somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Point mutation, chromosome breakage and mitotic recombination produce single spots; while twin spots are produced only by mitotic recombination. Exposure to 0.5 mM and 1 mM of amitrole clearly increased the frequency of small single, large single and total spots. Terbutryn, at the concentration of 5 mM, induced a slight increase in the frequency of small single and total spots, but this result could be false positive. The other three herbicides tested did not show any genotoxic effect. When heterozygous larvae for mwh and the multiple inverted TM3 balancer chromosomes were treated, significant increases in the frequency of mutant spots were only detected for amitrole. The observed spot frequencies were lower than those found in mwh/flr(3)50%) of the total spot induction was due to mitotic recombination.

  20. In vitro reactivation of sarin-inhibited human acetylcholinesterase (AChE) by bis-pyridinium oximes connected by xylene linkers.

    PubMed

    Acharya, Jyotiranjan; Dubey, Devendra Kumar; Srivastava, Ashish Kumar; Raza, Syed Kalbey

    2011-02-01

    A series of bis-pyridinium oximes connected by xylene linkers were synthesized and their in vitro reactivation potential was evaluated against human acetylcholinesterase (hAChE) inhibited by nerve agent sarin and the data were compared with 2-PAM and obidoxime. Among the synthesized compounds, N,N'-p-xylene-bis-[(2,2'-hydroxyiminomethyl)pyridinium] dibromide (3c) was found to be the most potent reactivator for hAChE inhibited by sarin. The oxime 3c exhibited 45% regeneration of inhibited hAChE, in comparison to 34% and 24% regeneration by 2-PAM and obidoxime, respectively, at a concentration of 10(-3) M within 10 min. The higher reactivation efficacies of these oximes were attributed to their acid dissociation constants (pKa). The pKa values of all the oximes were determined spectrophotometrically and correlated with their observed reactivation potential. This method involving the in vitro reactivation of inhibited hAChE may be useful for the screening of new oximes as reactivators.

  1. Chemical modification of a nanocrystalline TiO2 film for efficient electric connection of glucose oxidase.

    PubMed

    Sousa, Camila P; Polo, André S; Torresi, Roberto M; de Torresi, Susana I Córdoba; Alves, Wendel A

    2010-06-15

    A novel biosensor for glucose was prepared by adsorption of 1,1'-bis(4-carboxybenzyl)-4,4'-bipyridinium di-bromide compound (H(2)BpybcBr(2)) onto the surface of a nanocrystalline TiO(2) film deposited onto FTO glasses, which was used as a platform to assemble the enzyme glucose oxidase to the electrode surface. The H(2)BpybcBr(2)/TiO(2)/FTO modified electrode was characterized by scanning electron microscopy, X-ray fluorescence image, cyclic voltammograms and spectroelectrochemical measurements. The immobilization of GOD on functionalized TiO(2) film led to stable amperometric biosensing for glucose with a linear range from 153 micromol L(-1) to 1.30 mmol L(-1) and a detection limit of 51 micromol L(-1). The apparent Michaelis-Menten constant (K(m)) was estimated to be 3.76 mmol L(-1), which suggested a high enzyme-substrate affinity. The maximum electrode sensitivity was 1.25 microA mmol L(-1). The study proved that the combination of viologen mediators with TiO(2) film retains the electrocatalytic activity of the enzyme, and also enhances the electron transfer process, and hence regenerating the enzyme in the reaction with glucose.

  2. Fusion pore expansion is a slow, discontinuous, and Ca2+-dependent process regulating secretion from alveolar type II cells

    PubMed Central

    Haller, Thomas; Dietl, Paul; Pfaller, Kristian; Frick, Manfred; Mair, Norbert; Paulmichl, Markus; Hess, Michael W.; Fürst, Johannes; Maly, Karl

    2001-01-01

    In alveolar type II cells, the release of surfactant is considerably delayed after the formation of exocytotic fusion pores, suggesting that content dispersal may be limited by fusion pore diameter and subject to regulation at a postfusion level. To address this issue, we used confocal FRAP and N-(3-triethylammoniumpropyl)-4-(4-[dibutylamino]styryl) pyridinium dibromide (FM 1-43), a dye yielding intense localized fluorescence of surfactant when entering the vesicle lumen through the fusion pore (Haller, T., J. Ortmayr, F. Friedrich, H. Volkl, and P. Dietl. 1998. Proc. Natl. Acad. Sci. USA. 95:1579–1584). Thus, we have been able to monitor the dynamics of individual fusion pores up to hours in intact cells, and to calculate pore diameters using a diffusion model derived from Fick's law. After formation, fusion pores were arrested in a state impeding the release of vesicle contents, and expanded at irregular times thereafter. The expansion rate of initial pores and the probability of late expansions were increased by elevation of the cytoplasmic Ca2+ concentration. Consistently, content release correlated with the occurrence of Ca2+ oscillations in ATP-treated cells, and expanded fusion pores were detectable by EM. This study supports a new concept in exocytosis, implicating fusion pores in the regulation of content release for extended periods after initial formation. PMID:11604423

  3. A flexible approach to strained sandwich compounds: chiral [1]ferrocenophanes with boron, gallium, silicon, and tin in bridging positions.

    PubMed

    Sadeh, Saeid; Schatte, Gabriele; Müller, Jens

    2013-09-27

    The enantiomerically pure dibromoferrocene 3 [(Sp,Sp )-1,1'-dibromo-2,2'-di(isopropyl)ferrocene], equipped with two iPr groups in α positions, was prepared using known "Ugi amine" chemistry. Species 3 was targeted in order to gain access to new [1]ferrocenophanes ([1]FCPs) to be used as monomers for ring-opening polymerization. The iPr groups on the sandwich unit were introduced to stabilize bridging moieties, as well as to increase solubilities of targeted metallopolymers. The planar chiral dibromide 3 can quantitatively be lithiated at 0°C [2 equiv nBuLi, hexanes/thf (9:1), 30 min]. Salt-metathesis reactions with respective element dichloride species gave chiral [1]FCPs with a variety of bridging moieties [ERx =Ga[2-(Me2NCH2)C6H4] (4 a), SiMe2 (4 b), SntBu2 (4 c), BNiPr2 (4 d)]. The new [1]FCPs were fully characterized including single-crystal X-ray analysis. The stabilizing iPr groups on the Cp rings increase the thermal stabilities of 4 b-d compared to known [1]FCPs, equipped with the same bridging moieties. All three compounds 4 b-d are volatile and could be isolated by vacuum sublimation. Our new approach to [1]FCPs has the potential to overcome many of the existing difficulties in ferrocenophane chemistry, such as limited stability of starting monomers and low solubilities of resulting polyferrocenes.

  4. Chiral bora[1]ferrocenophanes: syntheses, mechanistic insights, and ring-opening polymerizations.

    PubMed

    Sadeh, Saeid; Bhattacharjee, Hridaynath; Khozeimeh Sarbisheh, Elaheh; Quail, J Wilson; Müller, Jens

    2014-12-01

    A series of new boron-bridged [1]ferrocenophanes ([1]FCPs) was prepared by salt-metathesis reactions between enantiomerically pure dilithioferrocenes and amino(dichloro)boranes (Et2 NBCl2 , iPr2 NBCl2 , or tBu(Me3 Si)NBCl2 ). The dilithioferrocenes were prepared in situ by lithium-bromine exchange from the respective planar-chiral dibromides (Sp ,Sp )-[1-Br-2-(HR2 C)H3 C5 ]2 Fe (R=Me or Et). In most of the cases, mixtures of the targeted [1]FCPs 4 and the unwanted 1,1'-bis(boryl)ferrocenes 5 were formed. The product ratio depends on the bulkiness of the amino group, the speed of addition of the amino(dichloro)borane, the alkyl group on Cp rings, and in particular on the reaction temperature. The formation of strained [1]FCPs is strongly favored by increased reaction temperatures. Secondly, CHEt2 groups at Cp rings favored the formation of the targeted [1]FCPs stronger than CHMe2 groups. These discoveries open up new possibilities to further suppress the formation of unwanted byproducts by a careful choice of the reaction temperature and through tailoring the bulkiness of CHR2 groups on ferrocene. Thermal ring-opening polymerizations of selected boron-bridged [1]FCPs gave metallopolymers with a Mw of 10 kDa (GPC).

  5. The Hazard Evaluation System and Information Service: A Physician's Resource in Toxicology and Occupational Medicine

    PubMed Central

    Hooper, Kim

    1982-01-01

    Hazard evaluation is an emerging science. The Hazard Evaluation System and Information Service (HESIS), part of California's program in preventive occupational health, is a resource for clinicians who wish to stay abreast of the relationship between toxicology and occupational health. For example, advances in assays for cancer or reproductive effects in test animals enable us to identify with greater confidence significant cancer or reproductive hazards among the increasing variety of workplace exposures. Occupational experiences with dibromochloropropane (DBCP), Kepone, bis(chloromethyl) ether, benzidine and vinyl chloride demonstrate the shortcomings of relying on human data. The latency period of cancer, limited sensitivity of epidemiologic studies and severity of effects require us to use animal test data to evaluate the potential cancer and reproductive risks of workplace substances. HESIS gives appropriate weight to experimental data in hazard evaluations of chemicals such as ethylene oxide, ethylene dibromide, polychlorinated biphenyls and the glycol ethers. A similar approach is apparent in the California Department of Health Services' recently released Carcinogen Identification Policy. PMID:6819719

  6. Genotoxicity study of a new tetraalkylammonium derivative of 6-methyluracil (agent No. 547).

    PubMed

    Karamova, Nazira S; Ivanchenko, Olga B; Ilinskaya, Olga N; Zobov, Vladimir V; Reznik, Vladimir S

    2002-03-01

    Agent No. 547 (1,3-bis[omega-(diethyl-ortho-nitrobenzylammonio)-pentyl]-6-methyluracil dibromide), a newly synthesized inhibitor of mammalian-specific acetyltcholinesterase (EC 3.1.1.7) was investigated for genotoxicity using the DNA-repair test, Ames test and in vivo micronucleus test with mouse peripheral blood erythrocytes. Agent No. 547 did not cause significant changes in growth of repair-deficient Escherichia coli tester strains. The compound was non-mutagenic in Salmonella typhimurium strains TA98 and TA100 with and without rat microsomal activation mixture. However, we observed a marked increase in number of His(+) revertants for both tester strains in preincubation assays. The results obtained in the micronucleus test indicate that agent No. 547 possesses significant clastogenic activity. At the high dose tested (0.5 mg/kg), the compound induced a seven-fold increase in the number of micronuclei over the spontaneous background 48 h after treatment. The results suggest that further work should be promoted to identify the metabolic pathways involved in genotoxicity of agent No. 547 in mammalian cells and to evaluate the real risk of its exposure.

  7. Ranking the potential carcinogenic hazards to workers from exposures to chemicals that are tumorigenic in rodents.

    PubMed Central

    Gold, L S; Backman, G M; Hooper, N K; Peto, R

    1987-01-01

    For 41 chemicals there exist both reasonable data on carcinogenic potency in experimental animals and also a defined Permissible Exposure Level (PEL), which is the upper limit of legally permissible chronic occupational exposure for U.S. workers. These 41 agents are ranked by an index that compares the permitted chronic human exposure to the chronic dose rate that induces tumors in 50% of laboratory animals. This index, the Permitted Exposure/Rodent Potency index, or PERP, does not estimate absolute risks directly, but rather suggests the relative hazards that such substances may pose. The PERP values for these 41 substances differ by more than 100,000-fold from each other. The PERP does not take into account the actual level of exposure or the number of exposed workers. Nevertheless, it might be reasonable to give priority attention to the reduction of allowable worker exposures to substances that appear most hazardous by this index and that some workers may be exposed to full-time near the PEL. Ranked by PERP, these chemicals are: ethylene dibromide, ethylene dichloride, 1,3-butadiene, tetrachloroethylene, propylene oxide, chloroform, formaldehyde, methylene chloride, dioxane, and benzene. PMID:3447901

  8. Effect of TiO2 particle size on the performance of viologen-anchored TiO2 electrochromic device.

    PubMed

    Kim, Yong Joo; Jeong, Hyun Ki; Seo, Jung Kyu; Chai, Seung Yong; Kim, Young Seok; Lim, Goo Il; Cho, Min Ho; Lee, Ik-Mo; Choi, Young S; Lee, Wan In

    2007-11-01

    The effect of TiO2 particle size on the performance of the electrochromic device (ECD) has been investigated in this work by applying the TiO2 nanoparticles in 7, 15, and 30 nm sizes. The phosphonated viologen, bis(2-phosphonoethyl)-4,4'-bipyridinium dibromide, was anchored on the TiO2 surfaces for the construction of ECD. The ECD derived from 7 nm-sized TiO2 demonstrated the highest contrast ratio with high optical transparency, whereas it showed the slowest switching response. The enhancement of coloration efficiency with decrease of TiO2 particle size is due to the increased amount of the anchored viologen on TiO2 electrode. On the other hand, the relatively slower switching response would be caused by the difficulty of diffusion for the electrolytes and counter-ions through the small pores of the nanocrystalline TiO2 electrode derived from 7 nm-sized nanoparticles.

  9. Glucose and lactate are equally effective in energizing activity-dependent synaptic vesicle turnover in purified cortical neurons.

    PubMed

    Morgenthaler, F D; Kraftsik, R; Catsicas, S; Magistretti, P J; Chatton, J-Y

    2006-08-11

    This study examines the role of glucose and lactate as energy substrates to sustain synaptic vesicle cycling. Synaptic vesicle turnover was assessed in a quantitative manner by fluorescence microscopy in primary cultures of mouse cortical neurons. An electrode-equipped perfusion chamber was used to stimulate cells both by electrical field and potassium depolarization during image acquisition. An image analysis procedure was elaborated to select in an unbiased manner synaptic boutons loaded with the fluorescent dye N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl)pyridinium dibromide (FM1-43). Whereas a minority of the sites fully released their dye content following electrical stimulation, others needed subsequent K(+) depolarization to achieve full release. This functional heterogeneity was not significantly altered by the nature of metabolic substrates. Repetitive stimulation sequences of FM1-43 uptake and release were then performed in the absence of any metabolic substrate and showed that the number of active sites dramatically decreased after the first cycle of loading/unloading. The presence of 1 mM glucose or lactate was sufficient to sustain synaptic vesicle cycling under these conditions. Moreover, both substrates were equivalent for recovery of function after a phase of decreased metabolic substrate availability. Thus, lactate appears to be equivalent to glucose for sustaining synaptic vesicle turnover in cultured cortical neurons during activity.

  10. Changes in polyphasic chlorophyll a fluorescence induction curve upon inhibition of donor or acceptor side of photosystem II in isolated thylakoids.

    PubMed

    Bukhov, Nikolai G; Egorova, Elena A; Govindachary, Sridharan; Carpentier, Robert

    2004-07-09

    The action of various inhibitors affecting the donor and acceptor sides of photosystem II (PSII) on the polyphasic rise of chlorophyll (Chl) fluorescence was studied in thylakoids isolated from pea leaves. Low concentrations of diuron and stigmatellin increased the magnitude of J-level of the Chl fluorescence rise. These concentrations barely affected electron transfer from PSII to PSI as revealed by the unchanged magnitude of the fast component (t(1/2) = 24 ms) of P700+ dark reduction. Higher concentrations of diuron and stigmatellin suppressed electron transport from PSII to PSI, which corresponded to the loss of thermal phase, the Chl fluorescence rise from J-level to the maximal, P-level. The effect of various concentrations of carbonylcyanide m-chlorophenylhydrazone (CCCP), which abolishes S-state cycle and binds at the plastoquinone site on QB, the secondary quinone acceptor PSII, on the Chl fluorescence rise was very similar to that of diuron and stigmatellin. Low concentrations of diuron, stigmatellin, or CCCP given on the background of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), which is shown to initiate the appearance of a distinct I-peak in the kinetics of Chl fluorescence rise measured in isolated thylakoids [BBA 1607 (2003) 91], increased J-step yield to I-step level and retarded Chl fluorescence rise from I-step to P-step. The increased J-step fluorescence rise caused by these three types of inhibitors is attributed to the suppression of the non-photochemical quenching of Chl fluorescence by [S2+ S3] states of the oxygen-evolving complex and oxidized P680, the primary donor of PSII reaction centers. In the contrary, the decreased fluorescence yield at P step (J-P, passing through I) is related to the persistence of a "plastoquinone"-type quenching owing to the limited availability of photochemically generated electron equivalents to reduce PQ pool in PSII centers where the S-state cycle of the donor side is modified by the inhibitor treatments.

  11. Transport of triplet excitons along continuous 100 nm polyfluorene chains

    DOE PAGES

    Xi, Liang; Bird, Matthew; Mauro, Gina; ...

    2014-12-03

    Triplet excitons created in poly-2,7-(9,9-dihexyl)fluorene (pF) chains with end trap groups in solution are efficiently transported to and captured by the end groups. The triplets explore the entire lengths of the chains, even for ~100 nm long chains enabling determination of the completeness of end capping. The results show that the chains continuous: they may contain transient barriers or traps, such as those from fluctuations of dihedral angles, but are free of major defects that stop motion of the triplets. Quantitative determinations are aided by the addition of a strong electron donor, TMPD, which removes absorption bands of the end-trappedmore » triplets. For chains having at least one end trap, triplet capture is quantitative on the 1 µs timescale imposed by the use of the donor. Fractions of chains having no end traps were 0.15 for pF samples with anthraquinone (AQ) end traps and 0.063 with naphthylimide (NI) end traps. These determinations agreed with measurements by NMR for short (<40 polymer repeat units (PRU)) chains, where NMR determinations are accurate. The results find no evidence for traps or barriers to transport of triplets, and places limits on the possible presence of defects as impenetrable barriers to less than one per 300 PRU. The present results present a paradigm different from the current consensus, derived from observations of singlet excitons, that conjugated chains are divided into “segments,” perhaps by some kind of defects. For the present pF chains, the segmentation either does not apply to triplet excitons or is transient so that the defects are healed or surmounted in times much shorter than 1 µs. Triplets on chains without end trap groups transfer to chains with end traps on a slower time scale. Rate constants for these bimolecular triplet transfer reactions were found to increase with the length of the accepting chain, as did rate constants for triplet transfer to the chains from small molecules like biphenyl. As a

  12. Transport of triplet excitons along continuous 100 nm polyfluorene chains

    SciTech Connect

    Xi, Liang; Bird, Matthew; Mauro, Gina; Asaoka, Sadayuki; Cook, Andrew R.; Chen, Hung -Cheng; Miller, John R.

    2014-12-03

    Triplet excitons created in poly-2,7-(9,9-dihexyl)fluorene (pF) chains with end trap groups in solution are efficiently transported to and captured by the end groups. The triplets explore the entire lengths of the chains, even for ~100 nm long chains enabling determination of the completeness of end capping. The results show that the chains continuous: they may contain transient barriers or traps, such as those from fluctuations of dihedral angles, but are free of major defects that stop motion of the triplets. Quantitative determinations are aided by the addition of a strong electron donor, TMPD, which removes absorption bands of the end-trapped triplets. For chains having at least one end trap, triplet capture is quantitative on the 1 µs timescale imposed by the use of the donor. Fractions of chains having no end traps were 0.15 for pF samples with anthraquinone (AQ) end traps and 0.063 with naphthylimide (NI) end traps. These determinations agreed with measurements by NMR for short (<40 polymer repeat units (PRU)) chains, where NMR determinations are accurate. The results find no evidence for traps or barriers to transport of triplets, and places limits on the possible presence of defects as impenetrable barriers to less than one per 300 PRU. The present results present a paradigm different from the current consensus, derived from observations of singlet excitons, that conjugated chains are divided into “segments,” perhaps by some kind of defects. For the present pF chains, the segmentation either does not apply to triplet excitons or is transient so that the defects are healed or surmounted in times much shorter than 1 µs. Triplets on chains without end trap groups transfer to chains with end traps on a slower time scale. Rate constants for these bimolecular triplet transfer reactions were found to increase with the length of the accepting chain, as did rate constants for triplet transfer to the chains from small molecules like biphenyl. As a result, a

  13. Control of Meloidogyne javanica and M. arenaria on kenaf and roselle with genetic resistance and nematicides.

    PubMed

    Minton, N A; Adamson, W C

    1979-01-01

    Kenaf (Hibiscus cannabinus) and roselle (H. sabdarifla) were evaluated in nematicide-treated and untreated field soil naturally infested with either Meloidogyne javanica or M. arenaria. Root-knot indices indicated that the kenaf breeding line j-l-113 had moderate resistance to M. javanica and low resistance to M. arenaria. Kenaf cv Everglades 71 was highly susceptible to both M. javanica and M. arenaria, and roselle breeding line A59-56 was highly resistant. Both nematode species reproduced on all plant entries, but more larvae were recovered from the soil in plots planted to Everglades 71 than in plots planted to j-l-l13 or A59-56. In untreated soil infested with M. javanica, dry-matter yields were greater (P = 0.05) for j-l-l13 and A59-56 than for Everglades 71. The percentages of live plants at harvest were: j-l-l13, 88; A59-56, 93; and Everglades 71, 9. Ethylene dibromide (1,2-dibromoethane) at 73.9 kg a.i./ha and DBCP (1,2-dibromo-3-chloropropane) at 17.6 kg a.i./ha increased dry-matter yields significantly for all entries planted in soil infested with M. arenaria. Carbofuran (2.3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) at 5.9 kg a.i./ha did not increase the dry-matter yields of any entry. None of the nematicides increased the growth of any entry significantly in soil infested with M. javanica.

  14. Dietary administration of diquat for 13 weeks does not result in a loss of dopaminergic neurons in the substantia nigra of C57BL/6J mice.

    PubMed

    Minnema, Daniel J; Travis, Kim Z; Breckenridge, Charles B; Sturgess, Nicholas C; Butt, Mark; Wolf, Jeffrey C; Zadory, Dan; Herberth, Mark T; Watson, Scott L; Cook, Andrew R; Botham, Philip A

    2016-03-01

    Male and female C57BL/6J mice were administered diquat dibromide (DQ∙Br2) in their diets at concentrations of 0 (control), 12.5 and 62.5 ppm for 13 weeks to assess the potential effects of DQ on the nigrostriatal dopaminergic system. Achieved dose levels at 62.5 ppm were 6.4 and 7.6 mg DQ (ion)/kg bw/day for males and females, respectively. A separate group of mice was administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) ip as a positive control. The comparative effects of DQ and MPTP on the substantia nigra pars compacta (SNpc) and/or striatum were assessed using neurochemical, neuropathological and stereological endpoints. Morphological and stereological assessments were performed by investigators who were "blinded" to dose group. DQ had no effect on striatal dopamine concentration or dopamine turnover. There was no evidence of neuronal degeneration, astrocytic or microglial activation, or a reduction in the number of tyrosine hydroxylase positive (TH(+)) neurons in the SNpc or neuronal processes in the striatum of DQ-treated mice. These results are consistent with the rapid clearance of DQ from the brain following a single dose of radiolabeled DQ. In contrast, MPTP-treated mice exhibited decreased striatal dopamine concentration, reduced numbers of TH(+) neurons in the SNpc, and neuropathological changes, including neuronal necrosis, as well as astrocytic and microglial activation in the striatum and SNpc. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Efficacy of irradiation vs thermal methods as quarantine treatments for tropical fruits

    NASA Astrophysics Data System (ADS)

    Moy, James H.

    1993-07-01

    Ionizing radiation can be effectively applied to fruits and vegetables for several purposes. The most feasible and potentially useful application is probably for disinfestation as a quarantine treatment. All stages of a fruit fly will become sterile upon being irradiated at a minimum dose of 0.15 kGy, the dose level approved by the USDA in January 1989 for treating Hawaiian papayas as a quarantine procedure. This is also well below the dose level approved in April, 1986 by the U.S. Food and Drug Administration for irradiating fresh foods for disinfestation and delaying maturation. Research on irradiation of several tropical fruits such as papayas, mangoes, lychees showed that the chemical, sensory and nutrient qualities of these fruits were well retained at 1.0 kGy, and the fruits would ripen normally or slightly delayed. Since September, 1984, thermal methods used by the papaya industry after ethylene dibromide was banned require treatment time of up to 7 hrs and have caused quality problems. Some of the fruits treated by the hot air or the double-dip hot water method lack flavor and had lumpy texture. The vapor heat method as now used is quite expensive. Irradiation studies have proved the efficacy of the process to disinfest tropical fruits of fruit files. Market test of irradiated Hawaiian papayas in 1987 showed that consumers preferred irradiated papayas over hot water treated papayas by 11 to 1. Thus the only hurdle to overcome in using irradiation for tropical fruits is to convince the consumers that irradiated fruits are wholesome and safe for human consumption, which has been amply proven with scientific data obtained during the past three decades, and further proven with the marketing of irradiated fruits in the U.S.A. since early 1992.

  16. Structures of di-substituted and charged cavitands

    NASA Astrophysics Data System (ADS)

    Aniol, Alexandra; Mallick, Bert; Winter, Manuela; Feigel, Martin

    2017-09-01

    Calix[4]resorcinarene based cavitands build from resorcinol or 2-methylresorcinol were synthesized with a focus on systems having less than four substituents at the upper rim. The structures of the synthesized di-substituted calix[4]resorcinarenes, 2 (5,17-Dibromo-4(24),6(10),12(16),18(22)-tetramethylendioxy-2,8,14,20-tetrapentylresorcin[4]arene) and 4 (5,11-Bis[urotropinyliummethyl]-17,23-dimethyl-4(24),6(10),12(16),18(22)-tetramethylendioxy-2,8,14,20-tetrapentylresorcin[4]arene-dibromide), together with the tetra-substituted calix[4]resorcinarene 1 (5,11,17,23-Tetrabromo-4(24),6(10),12(16),18(22)-tetramethylendioxy-2,8,14,20-tetrapentylresorcin[4]arene) were investigated via 1H, 13C NMR and X-ray single crystal diffraction. The stereochemistry of the anti-dibromo-resorcinarene-cavitand 2 and of the syn-bis(urotropinyliummethyl)-cavitand 4 was anticipated by their NMR-data and is confirmed by X-ray derived structures. Small solvent molecules (n-pentane and chloroform resp.) are included in the resorcinarene cavities of 1, 2 and 4. Compound 4 builds a crystal in which polar layers of the substituents at the upper rim of the cavitand, consisting of the charged urotropinyl units and their bromide counter ions, alternate with lipophilic layers filled with the pentyl chains at the lower rim of the cavitand. So a multiple bilayer structure is formed via head to head and tail to tail arrangements as found in the crystal structures of membrane lipids.

  17. Enhancing aerobic biodegradation of 1,2-dibromoethane in groundwater using ethane or propane and inorganic nutrients

    NASA Astrophysics Data System (ADS)

    Hatzinger, Paul B.; Streger, Sheryl H.; Begley, James F.

    2015-01-01

    1,2-Dibromoethane (ethylene dibromide; EDB) is a probable human carcinogen that was previously used as both a soil fumigant and a scavenger in leaded gasoline. EDB has been observed to persist in soils and groundwater, particularly under oxic conditions. The objective of this study was to evaluate options to enhance the aerobic degradation of EDB in groundwater, with a particular focus on possible in situ remediation strategies. Propane gas and ethane gas were observed to significantly stimulate the biodegradation of EDB in microcosms constructed with aquifer solids and groundwater from the FS-12 EDB plume at Joint Base Cape Cod (Cape Cod, MA), but only after inorganic nutrients were added. Ethene gas was also effective, but rates were appreciably slower than for ethane and propane. EDB was reduced to < 0.02 μg/L, the Massachusetts state Maximum Contaminant Level (MCL), in microcosms that received ethane gas and inorganic nutrients. An enrichment culture (BE-3R) that grew on ethane or propane gas but not EDB was obtained from the site materials. The degradation of EDB by this culture was inhibited by acetylene gas, suggesting that degradation is catalyzed by a monooxygenase enzyme. The BE-3R culture was also observed to biodegrade 1,2-dichloroethane (DCA), a compound commonly used in conjunction with EDB as a lead scavenger in gasoline. The data suggest that addition of ethane or propane gas with inorganic nutrients may be a viable option to enhance degradation of EDB in groundwater aquifers to below current state or federal MCL values.

  18. Occurrence and Potential Human-Health Relevance of Volatile Organic Compounds in Drinking Water from Domestic Wells in the United States

    PubMed Central

    Rowe, Barbara L.; Toccalino, Patricia L.; Moran, Michael J.; Zogorski, John S.; Price, Curtis V.

    2007-01-01

    Background As the population and demand for safe drinking water from domestic wells increase, it is important to examine water quality and contaminant occurrence. A national assessment in 2006 by the U.S. Geological Survey reported findings for 55 volatile organic compounds (VOCs) based on 2,401 domestic wells sampled during 1985–2002. Objectives We examined the occurrence of individual and multiple VOCs and assessed the potential human-health relevance of VOC concentrations. We also identified hydrogeologic and anthropogenic variables that influence the probability of VOC occurrence. Methods The domestic well samples were collected at the wellhead before treatment of water and analyzed for 55 VOCs. Results were used to examine VOC occurrence and identify associations of multiple explanatory variables using logistic regression analyses. We used a screening-level assessment to compare VOC concentrations to U.S. Environmental Protection Agency maximum contaminant levels (MCLs) and health-based screening levels. Results We detected VOCs in 65% of the samples; about one-half of these samples contained VOC mixtures. Frequently detected VOCs included chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene. VOC concentrations generally were < 1 μg/L. One or more VOC concentrations were greater than MCLs in 1.2% of samples, including dibromochloropropane, 1,2-dichloropropane, and ethylene dibromide (fumigants); perchloroethene and trichloroethene (solvents); and 1,1-dichloroethene (organic synthesis compound). Conclusions Drinking water supplied by domestic wells is vulnerable to low-level VOC contamination. About 1% of samples had concentrations of potential human-health concern. Identifying factors associated with VOC occurrence may aid in understanding the sources, transport, and fate of VOCs in groundwater. PMID:18007981

  19. A comparative study and evaluation of sulfamethoxazole adsorption onto organo-montmorillonites.

    PubMed

    Lu, Laifu; Gao, Manglai; Gu, Zheng; Yang, Senfeng; Liu, Yuening

    2014-12-01

    Three organo-montmorillonites were prepared using surfactants, and their adsorption behaviors toward sulfamethoxazole (SMX) were investigated. The surfactants used were cetyltrimethyl ammonium bromide (CTMAB), 3-(N,N-dimethylhexadecylammonio) propane sulfonate (HDAPS) and 1,3-bis(hexadecyldimethylammonio)-propane dibromide (BHDAP). The properties of the organo-montmorillonites were characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption-desorption isotherm measurements. Results showed that the interlayer spacing of montmorillonite was increased and the surface area as well as the morphology were changed. Batch adsorption experiments showed that the surfactant loading amount had a great effect on the adsorption of SMX. The adsorption process was pH dependent and the maximum adsorption capacity was obtained at pH3 for HDAPS-Mt, while CTMAB-Mt and BHDAP-Mt showed a high removal efficiency at 3-11. The adsorption capacity increased with the initial SMX concentration and contact time but decreased with increasing solution ionic strength. Kinetic data were best described by the pseudo second-order model. Equilibrium data were best represented by the Langmuir model, and the Freundlich constant (n) indicated a favorable adsorption process. The maximum adsorption capacity of SMX was 235.29 mg/g for CTMAB-Mt, 155.28 mg/g for HDAPS-Mt and 242.72 mg/g for BHDAP-Mt. Thermodynamic parameters were calculated to evaluate the spontaneity and endothermic or exothermic nature. The adsorption mechanism was found to be dominated by electrostatic interaction, while hydrophobic interaction played a secondary role.

  20. On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

    PubMed Central

    Mazzanti, Virginia; Cacciarini, Martina; Broman, Søren L; Parker, Christian R; Schau-Magnussen, Magnus; Bond, Andrew D

    2012-01-01

    Summary Background: The dihydroazulene (DHA)/vinylheptafulvene (VHF) system (with two cyano groups at C1) functions as a photo-/thermoswitch. Direct ionic bromination of DHA has previously furnished a regioselective route to a 7,8-dibromide, which by elimination was converted to a 7-bromo-substituted DHA. This compound has served as a central building block for functionalization of the DHA by palladium-catalyzed cross-coupling reactions. The current work explores another bromination protocol for achieving the isomeric 3-bromo-DHA and also explores the outcome of additional bromination of this compound as well as of the known 7-bromo-DHA. Results: Radical bromination on two different VHFs by using N-bromosuccinimide/benzoyl peroxide and light, followed by a ring-closure reaction generated the corresponding 3-bromo-DHAs, as confirmed in one case by X-ray crystallography. According to a 1H NMR spectroscopic study, the ring closure of the brominated VHF seemed to occur readily under the reaction conditions. A subsequent bromination–elimination protocol provided a 3,7-dibromo-DHA. In contrast, treating the known 7-bromo-DHA with bromine generated a very labile species that was converted to a new 3,7-dibromoazulene, i.e., the fully unsaturated species. Azulenes were also found to form from brominated compounds when left standing for a long time in the solid state. Kinetics measurements reveal that the 3-bromo substituent enhances the rate of the thermal conversion of the VHF to DHA, which is opposite to the effect exerted by a bromo substituent in the seven-membered ring. Conclusion: Two general procedures for functionalizing the DHA core with a bromo substituent (at positions 3 and 7, respectively) are now available with the DHA as starting material. PMID:23015846

  1. Allosteric binding sites on muscarinic acetylcholine receptors.

    PubMed

    Wess, Jürgen

    2005-12-01

    In this issue of Molecular Pharmacology, Tränkle et al. (p. 1597) present new findings regarding the existence of a second allosteric site on the M2 muscarinic acetylcholine receptor (M2 mAChR). The M2 mAChR is a prototypic class A G protein-coupled receptor (GPCR) that has proven to be a very useful model system to study the molecular mechanisms involved in the binding of allosteric GPCR ligands. Previous studies have identified several allosteric muscarinic ligands, including the acetylcholinesterase inhibitor tacrine and the bis-pyridinium derivative 4,4'-bis-[(2,6-dichloro-benzyloxy-imino)-methyl]-1,1'-propane-1,3-diyl-bis-pyridinium dibromide (Duo3), which, in contrast to conventional allosteric muscarinic ligands, display concentration-effect curves with slope factors >1. By analyzing the interactions of tacrine and Duo3 with other allosteric muscarinic agents predicted to bind to the previously identified ;common' allosteric binding site, Tränkle et al. provide evidence suggesting that two allosteric agents and one orthosteric ligand may be able to bind to the M2 mAChR simultaneously. Moreover, studies with mutant mAChRs indicated that the M2 receptor epitopes involved in the binding of tacrine and Duo3 may not be identical. Molecular modeling and ligand docking studies suggested that the additional allosteric site probably represents a subdomain of the receptor's allosteric binding cleft. Because allosteric binding sites have been found on many other GPCRs and drugs interacting with these sites are thought to have great therapeutic potential, the study by Tränkle et al. should be of considerable general interest.

  2. Occurrence and potential human-health relevance of volatile organic compounds in drinking water from domestic wells in the United States.

    USGS Publications Warehouse

    Rowe, B.L.; Toccalino, P.L.; Moran, M.J.; Zogorski, J.S.; Price, C.V.

    2007-01-01

    BACKGROUND: As the population and demand for safe drinking water from domestic wells increase, it is important to examine water quality and contaminant occurrence. A national assessment in 2006 by the U.S. Geological Survey reported findings for 55 volatile organic compounds (VOCs) based on 2,401 domestic wells sampled during 1985-2002. OBJECTIVES: We examined the occurrence of individual and multiple VOCs and assessed the potential human-health relevance of VOC concentrations. We also identified hydrogeologic and anthropogenic variables that influence the probability of VOC occurrence. METHODS: The domestic well samples were collected at the wellhead before treatment of water and analyzed for 55 VOCs. Results were used to examine VOC occurrence and identify associations of multiple explanatory variables using logistic regression analyses. We used a screening-level assessment to compare VOC concentrations to U.S. Environmental Protection Agency maximum contaminant levels (MCLs) and health-based screening levels. RESULTS: We detected VOCs in 65% of the samples; about one-half of these samples contained VOC mixtures. Frequently detected VOCs included chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene. VOC concentrations generally were < 1 microg/L. One or more VOC concentrations were greater than MCLs in 1.2% of samples, including dibromochloropropane, 1,2-dichloropropane, and ethylene dibromide (fumigants); perchloroethene and trichloroethene (solvents); and 1,1-dichloroethene (organic synthesis compound). CONCLUSIONS: Drinking water supplied by domestic wells is vulnerable to low-level VOC contamination. About 1% of samples had concentrations of potential human-health concern. Identifying factors associated with VOC occurrence may aid in understanding the sources, transport, and fate of VOCs in groundwater.

  3. Nanoporous array anodic titanium-supported co-polymeric ionic liquids as high performance solid-phase microextraction sorbents for hydrogen bonding compounds.

    PubMed

    Jia, Jing; Liang, Xiaojing; Wang, Licheng; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2013-12-13

    A nanoporous array anodic titanium-supported co-polymeric ionic liquids (NAAT/PILs) solid-phase microextraction (SPME) fiber was prepared in situ on the titanium wire. NAAT was selected as the substrate, in view of its high surface-to-volume ratio, easy preparation, mechanical stability, and rich titanol groups on its surface which can anchor silica coupling agent containing vinyl and then introduce ionic liquid copolymers as sorbents. In this work, 1-vinyl-3-nonanol imidazolium bromide ([C9OHVIm]Br) and 1,4-di(3-vinylimidazolium) butane dibromide ([(VIM)2C4]2[Br]) were synthesized and used as monomer and crosslinker, respectively. Extraction properties of the NAAT/PILs fiber for polar alcohols and volatile fatty acids (VFAs) in aqueous matrix were examined using gaseous sampling-SPME (GS-SPME) and headspace SPME (HS-SPME) mode, respectively. Combining the superior properties of NAAT substrate and the strong hydrogen bond interaction of PILs to polar compounds, the NAAT/PILs SPME fiber showed much higher adsorption affinity to aliphatic alcohols than bare NAAT and pure PILs fibers. The detection limits (LOD) of established GS-SPME-GC-FID method are in the range of 0.35-17.30ngL(-1) with a linear range from 0.01 to 500ngmL(-1). Also, it showed high extraction performance toward volatile fatty acids (VFAs) compounds from aqueous matrix. Under the optimized SPME conditions, wide linear ranges were obtained with correlation coefficients (R(2)) greater than 0.99 and limits of detection were in the range of 0.85-8.74ngL(-1). Moreover, real-world samples were analyzed and good results were obtained.

  4. Data related uncertainty in near-surface vulnerability assessments for agrochemicals in the San Joaquin Valley.

    PubMed

    Loague, Keith; Blanke, James S; Mills, Melissa B; Diaz-Diaz, Ricardo; Corwin, Dennis L

    2012-01-01

    Precious groundwater resources across the United States have been contaminated due to decades-long nonpoint-source applications of agricultural chemicals. Assessing the impact of past, ongoing, and future chemical applications for large-scale agriculture operations is timely for designing best-management practices to prevent subsurface pollution. Presented here are the results from a series of regional-scale vulnerability assessments for the San Joaquin Valley (SJV). Two relatively simple indices, the retardation and attenuation factors, are used to estimate near-surface vulnerabilities based on the chemical properties of 32 pesticides and the variability of both soil characteristics and recharge rates across the SJV. The uncertainties inherit to these assessments, derived from the uncertainties within the chemical and soil data bases, are estimated using first-order analyses. The results are used to screen and rank the chemicals based on mobility and leaching potential, without and with consideration of data-related uncertainties. Chemicals of historic high visibility in the SJV (e.g., atrazine, DBCP [dibromochloropropane], ethylene dibromide, and simazine) are ranked in the top half of those considered. Vulnerability maps generated for atrazine and DBCP, featured for their legacy status in the study area, clearly illustrate variations within and across the assessments. For example, the leaching potential is greater for DBCP than for atrazine, the leaching potential for DBCP is greater for the spatially variable recharge values than for the average recharge rate, and the leaching potentials for both DBCP and atrazine are greater for the annual recharge estimates than for the monthly recharge estimates. The data-related uncertainties identified in this study can be significant, targeting opportunities for improving future vulnerability assessments.

  5. Characterization of monoclonal antibodies that strongly inhibit Electrophorus electricus acetylcholinesterase.

    PubMed

    Remy, M H; Frobert, Y; Grassi, J

    1995-08-01

    In this study, we describe three different monoclonal antibodies (mAbs Elec-403, Elec-408, and Elec-410) directed against Electrophorus electricus acetylcholinesterase (AChE) which were selected as inhibitors for this enzyme. Two of these antibodies (Elec-403 and Elec-410), recognized overlapping but different epitopes, competed with snake venom toxin fasciculin for binding to the enzyme, and thus apparently recognized the peripheral site of AChE. In addition, the binding of Elec-403 was antagonized by 1,5-bis(4-allyldimethylammoniumphenyl)pentan-3-one dibromide (BW284C51) and propidium, indicating that the corresponding epitope encompassed the anionic site involved in the binding of these low-molecular-mass inhibitors. The third mAb (Elec-408), was clearly bound to another site on the AChE molecule, and its inhibitory effect was cumulative with those of Elec-403, Elec-410, and fasciculin. All mAbs bound AChE with high affinity and were as strong inhibitors with an apparent Ki values less than 0.1 nM. Elec-403 was particularly efficient with an inhibitory activity similar to that of fasciculin. Inhibition was observed with both charged (acetylthiocholine) and neutral substrates (o-nitrophenyl acetate) and had the characteristics of a non-competitive process. Elec-403 and Elec-410 probably exert their effect by triggering allosteric transitions from the peripheral site to the active site. The epitope recognized by mAb Elec-408 has not been localized, but it may correspond to a new regulatory site on AChE.

  6. Self-Assembly in Aqueous Oppositely Charged Gemini Surfactants: A Correlation between Morphology and Solubilization Efficacy.

    PubMed

    Singh, Sneha; Bhadoria, Arti; Parikh, Kushan; Yadav, Sanjay Kumar; Kumar, Sugam; Aswal, V K; Kumar, Sanjeev

    2017-09-21

    Micellization behavior of oppositely charged gemini surfactants (anionic surfactant; phosphoric acid, P,P'-1,4-butanedieyl, P,P'-didodecylester, disodium salt (12-4-12A), and cationic surfactant; butanediyl-1,4, bis (N,N-hexadecyl ammonium) dibromide (16-4-16) or (D-isosorbate-1,4-diyl bis(N,N-dimethyl-N-hexadecylammonium acetoxy) dichloride (16-Isb-16)) has been studied (individually or of a gemini mixture) by conductivity and surface tension measurements. Critical micelle concentration (CMC) data show both synergistic (for 12-4-12A + 16-Isb-16) and antagonistic (for 12-4-12A + 16-4-16) interactions between the two components. Small angle neutron scattering (SANS) measurement shows formation of various aggregates, spherical (or ellipsoidal), rod-shaped, and vesicular, by changing the mole fraction (at fixed total surfactant concentration, 10 mM). Viscosity, zeta (ζ)-potential, and transmission electron microscopy (TEM) data are found in conformity of SANS results. Surprisingly, two morphologies (vesicles and rod-shaped micelles) show stability in a wide temperature range (303-343 K). The behavior has been explained on the basis of temperature induced dehydration and depletion of micellar charge. Aqueous gemini mixtures, of different morphologies, have been used for the determination of solubilization efficacy (using UV-visible spectrophotometer) toward polycyclic aromatic hydrocarbons (PAHs: anthracene; pyrene or fluorene). Molar solubilization ratio (MSR) data suggest that vesicles enhance the solubilization efficacy. SANS analysis shows that vesicle bilayer thickness increases upon PAH solubilization. The order of bilayer thickness increase is found to be anthracene > pyrene > fluorene, which is in the same order as the aqueous solubility of PAHs. This is the first report which correlates morphology to the solubilization efficacy.

  7. Structural and transfection properties of amine-substituted gemini surfactant-based nanoparticles

    SciTech Connect

    Wettig,S.; Badea, I.; Donkuru, M.; Verrall, R.; Foldvari, M.

    2007-01-01

    Increases in DNA transfection efficiencies for non-viral vectors can be achieved through rational design of novel cationic building blocks. Based on previous results examining DNA condensation by polyamines, novel gemini surfactants have been designed that incorporate aza or imino substituents within the spacer group in order to increase interactions with DNA and potentially improve their DNA transfection ability. Transfection efficiencies and cell toxicity of gemini nanoparticles constructed from plasmid DNA, gemini surfactant, and a neutral lipid were measured in COS7 cells using a luciferase assay. Structural properties of nanoparticles were examined by using circular dichroism, particle size, zeta potential, and small-angle X-ray scattering (SAXS) measurements. The incorporation of aza and imino substituents within the spacer group was observed to enhance the transfection ability of gemini surfactants. Incorporation of an imino group in the structure of the 1,9-bis(dodecyl)-1,1,9,9-tetramethyl-5-imino-1,9-nonanediammonium dibromide surfactant (12-7NH-12) resulted in a statistically significant (p < 0.01) 9-fold increase in transfection compared to an unsubstituted gemini surfactant and a 3-fold increase compared to the corresponding aza-substituted compound. A pH-dependent transition in size and zeta potential was observed to occur at pH 5.5 for complexes formed from the 12-7NH-12 compound. SAXS results show weakly ordered structures and the presence of multiple phases. The incorporation of a pH-active imino group within the spacer of the gemini surfactant results in a significant increase in transfection efficiency that can be related to both pH-induced changes in nanoparticle structure and the formation of multiple phases that more readily allow for membrane fusion that may facilitate DNA release.

  8. Laboratory investigations of the photochemical decay of alkylbromides trapped in ice

    NASA Astrophysics Data System (ADS)

    Schrems, Otto; Okaikwei, Bismark; Bluszcz, Thaddäus

    2014-05-01

    Photochemical reactions of atmospheric trace gases taking place at the surface of atmospheric ice particles and in bulk ice are important in tropospheric chemistry but also in polar and alpine snowpack chemistry. Consequently, the understanding of the uptake und incorporation of tropospheric trace gases in water ice as well as their interactions with water molecules is very important for the understanding of processes which occur in ice particles and at the air/ice interface. Reactive atmospheric trace gases trapped in ice are subject of photochemical reactions when irradiated with solar UV radiation. Among such compounds bromine species are highly interesting due to their potential of depleting ozone both in the stratosphere and troposphere. Methyl bromide (CH3Br) is the largest bromine carrier to the stratosphere. It has both natural and anthropogenic sources. In this contribution we will present the results of our laboratory studies of alkyl bromides (methyl bromide (CH3Br), methyl dibromide (CH2Br2), n-propyl bromide (C3H7Br), 1,2-dibromoethane C2H4Br2)), trapped in water ice. We have simulated the UV photochemistry of these brominated alkanes isolated in ice films kept at 16 K and for comparison in solid argon matrices. The photoproducts formed in the ice have been identified by means of FTIR spectroscopy. Reflection absorption infrared spectroscopy (RAIRS) is especially useful to study nascent ice surfaces, kinetics of adsorption/decomposition, and heterogeneous catalysis. Among the observed photoproducts we could identify carbon monoxide and carbon dioxide for each alkyl bromide studied. The photoproduct HBr is dissociated in the bulk ice. Based on the experimental observations possible reaction mechanisms will be discussed.

  9. Simulation of the effect of remediation on EDB and 1,2-DCA plumes at sites contaminated by leaded gasoline

    NASA Astrophysics Data System (ADS)

    Henderson, James K.; Falta, Ronald W.; Freedman, David L.

    2009-08-01

    An analytical model is used to simulate the effects of partial source removal and plume remediation on ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) plumes at contaminated underground storage tank (UST) sites. The risk posed by EDB, 1,2-DCA, and commingled gasoline hydrocarbons varies throughout the plume over time. Dissolution from the light nonaqueous phase liquid (LNAPL) determines the concentration of each contaminant near the source, but biological decay in the plume has a greater influence as distance downgradient from the source increases. For this reason, compounds that exceed regulatory standards near the source may not in downgradient plume zones. At UST sites, partial removal of a residual LNAPL source mass may serve as a stand alone remedial technique if dissolved concentrations in the source zone are within several orders of magnitude of the applicable government or remedial standards. This may be the case with 1,2-DCA; however, EDB is likely to be found at concentrations that are orders of magnitude higher than its low Maximum Contaminant Level (MCL) of 0.05 μg/L (micrograms per liter). For sites with significant EDB contamination, even when plume remediation is combined with source depletion, significant timeframes may be required to mitigate the impact of this compound. Benzene and MTBE are commonly the focus of remedial efforts at UST sites, but simulations presented here suggest that EDB, and to a lesser extent 1,2-DCA, could be the critical contaminants to consider in the remediation design process at many sites.

  10. Dissolution and regeneration of hide powder/cellulose composite in Gemini imidazolium ionic liquid.

    PubMed

    Wang, Guowei; Guo, Jiarong; Zhuang, Linghua; Wang, Yan; Xu, Bin

    2015-05-01

    Gemini imidazolium ionic liquid, 3,3'-[1,2-ethanediylbis (oxy-2,1-ethanediyl)]-bis[1-methyl-imidazolium]-dibromide ([C6O2(mim)2][Br]2), was used for the dissolution and regeneration of white hide powder (from pigskin), and blend white hide powder with cellulose for the easy production of white hide powder/cellulose composite. Dissolution performance of white hide powder in [C6O2(mim)2][Br]2 was studied. The native white hide powder and [C6O2(mim)2][Br]2 regenerated white hide powder were characterized by FT-IR, XRD, DSC-TG and FE-SEM. The results showed that [C6O2(mim)2][Br]2 was a good solvent to white hide powder. The dissolution time was 55 min when the white hide powder was 8% at 120°C. The dissolution time of [C6O2(mim)2][Br]2 for white hide powder was shorter than those of common ionic liquids. The triple helical structure of white hide powder was partly destroyed during [C6O2(mim)2][Br]2 dissolution. The possible mechanism of white hide powder dissolution in [C6O2(mim)2][Br]2 and the regeneration of white hide powder in methanol had been proposed. White hide powder/cellulose composites were successfully dissolved in [C6O2(mim)2][Br]2. The performance of white hide powder/cellulose film was measured by FT-IR and TG. The tensile strength, and elongation at break of white hide powder/cellulose composite films were tested. This work demonstrated that the white hide powder/cellulose composite exhibited some potential in collagen-based tissue engineering.

  11. The chemical behavior of terminally tert-butylated polyolefins.

    PubMed

    Klein, Dagmar; Hopf, Henning; Jones, Peter G; Dix, Ina; Hänel, Ralf

    2015-01-01

    The chemical behavior of various oligoenes 2 has been studied. The catalytic hydrogenation of diene 3 yielded monoene 4. Triene 7 was hydrogenated to diene 8, monoene 9 and saturated hydrocarbon 10. Bromine addition to 3 and 7 yielded the dibromides 17 and 18, respectively, i.e., the oligoene system has been attacked at its terminal olefinic carbon atoms. Analogously, the higher vinylogs 19 and 20 yielded the 1,8- and 1,10-bromine adduts 23 and 24, respectively, when less than 1 equivalent of bromine was employed. Treatment of tetraene 19 with excess bromine provided tetrabromide 25. In epoxidation reactions, both with meta-chloroperbenzoic acid (MCPBA) and dimethyldioxirane (DMDO) two model oligoenes were studied: triene 7 and tetraene 19. Whereas 7 furnished the rearrangement product 31 with MCPBA, it yielded the symmetrical epoxide 32 with DMDO. Analogously, 19 was converted to mono-epoxide 33 with MCPBA and to 34 with DMDO. Diels-Alder addition of 7 with N-phenyltriazolinedione (PTAD) did not take place. Extension of the conjugated π-system to the next higher vinylog, 19, caused NPTD-addition to the symmetrical adduct 37 in good yield. Comparable results were observed on adding NPTD (equivalent amount) to pentaene 20 and hexaene 21. Using 36 in excess provided the 2:1-adduct 40 from 21 and led to a complex mixture of adducts from heptaene 22. With tetracyanoethylene (TCNE) as the dienophile, tetraolefin 19 yielded the symmetrical adduct 43, although the reaction temperature had to be increased. Pentaene 20 and hexaene 21 led to corresponding results, adducts 44 and 45 being produced in acceptable yields. With nonaene 42 and TCNE the 2:1-adduct 48 was generated according to its spectroscopic data. Exploratory photochemical studies were carried out with tetraene 19 as the model compound. On irradiation this reacted with oxygen to the stable endo-peroxide 52.

  12. The chemical behavior of terminally tert-butylated polyolefins

    PubMed Central

    Klein, Dagmar; Jones, Peter G; Dix, Ina; Hänel, Ralf

    2015-01-01

    Summary The chemical behavior of various oligoenes 2 has been studied. The catalytic hydrogenation of diene 3 yielded monoene 4. Triene 7 was hydrogenated to diene 8, monoene 9 and saturated hydrocarbon 10. Bromine addition to 3 and 7 yielded the dibromides 17 and 18, respectively, i.e., the oligoene system has been attacked at its terminal olefinic carbon atoms. Analogously, the higher vinylogs 19 and 20 yielded the 1,8- and 1,10-bromine adduts 23 and 24, respectively, when less than 1 equivalent of bromine was employed. Treatment of tetraene 19 with excess bromine provided tetrabromide 25. In epoxidation reactions, both with meta-chloroperbenzoic acid (MCPBA) and dimethyldioxirane (DMDO) two model oligoenes were studied: triene 7 and tetraene 19. Whereas 7 furnished the rearrangement product 31 with MCPBA, it yielded the symmetrical epoxide 32 with DMDO. Analogously, 19 was converted to mono-epoxide 33 with MCPBA and to 34 with DMDO. Diels–Alder addition of 7 with N-phenyltriazolinedione (PTAD) did not take place. Extension of the conjugated π-system to the next higher vinylog, 19, caused NPTD-addition to the symmetrical adduct 37 in good yield. Comparable results were observed on adding NPTD (equivalent amount) to pentaene 20 and hexaene 21. Using 36 in excess provided the 2:1-adduct 40 from 21 and led to a complex mixture of adducts from heptaene 22. With tetracyanoethylene (TCNE) as the dienophile, tetraolefin 19 yielded the symmetrical adduct 43, although the reaction temperature had to be increased. Pentaene 20 and hexaene 21 led to corresponding results, adducts 44 and 45 being produced in acceptable yields. With nonaene 42 and TCNE the 2:1-adduct 48 was generated according to its spectroscopic data. Exploratory photochemical studies were carried out with tetraene 19 as the model compound. On irradiation this reacted with oxygen to the stable endo-peroxide 52. PMID:26425183

  13. Electrocatalysis with vitamin B sub 12 in water-in-oil microemulsions at carbon-fiber microelectrodes

    SciTech Connect

    Owlia, A.

    1989-01-01

    Microemulsions are clear, thermodynamically stable dispersions containing oil, surfactant and water. They are crude models of biological membranes and can be used to investigate some of the organizational influence of membranes in lipid and protein synthesis, energy transduction, ion and group transport, etc. This thesis concerns the investigation of microemulsion properties as media in which catalytic reduction of vicinal dibromides can take place with the electrochemically generated Co(I) form of Vitamin B{sub 12}. Methods to study fundamental properties of resistive w/o AOT/H{sub 2}O/isoctane were developed. Microelectrodes of approximate radius of 6 {mu}m were prepared and characterized. Nonlinear regression was applied to the analysis of steady state voltammograms obtained at carbon-fiber microelectrodes. Reversible regression models were used to analyze data for oxidation of ferrocene in acetonitrile with and without added electrolyte. An estimate of cell resistance in highly resistive media was obtained by including ohmic drop in the model for reversible electron transfer. The electrocatalytic reduction of 1,2-dibromoethane (EDB), 1,2-dibromobutane (DBB), and trans-1,2-dibromocyclohexane (DBCH) with Vitamin B{sub 12} in pH {le} 3 water MeCN and w/o microemulsions of AOT/H{sub 2}O/isoctane at carbon fiber microelectrode was investigated. The microviscosity of w/o microemulsions were estimated from the Stokes-Einstein equation using ferrocene as a probe. Results show that the diffusion of molecules in the microemulsions are similar to their diffusion in organic phase (isoctane). Nonlinear regression analysis of the data for AOT w/o microemulsions describing the dependence of D{prime} on C{sub x} enables an estimate of micelle diffusion coefficients.

  14. Effects of the workplace on fertility and related reproductive outcomes.

    PubMed Central

    Baranski, B

    1993-01-01

    This report reviews the recent literature on the adverse effects of occupational factors on fertility and related reproductive outcomes. Few studies fulfill the criteria of good study design because of small sample size, insensitive measures of effect, selection, recall, and observation bias, weak if any control of confounding factors, bad definition of exposure, inability to analyze a dose-response relationship, and inadequate statistical analysis. The high prevalence of unsuccessful reproductive outcomes in the general population makes the design of human fertility studies difficult. Although a number of publications indicate that certain occupational factors and settings adversely affect both male and female fertility, it is virtually impossible to estimate the proportion of infertility due to occupational factors in the general population. The collected data suggest that the exposure to the following substances or occupational settings may affect a function of male genital system, leading to sperm abnormalities, hyperestrogenism, impotence, infertility, and/or increased spontaneous abortion rate in wives of exposed workers: alkylmercury, antimonide, anesthetic gases, boron, carbon disulfide, chlorodecone, chloroprene, some carbamates (carbaryl), diaminostilbene, 1,2-dibromo-3-chloropropane, ethylene glycol ethers, ethylene dibromide, inorganic lead, manganese, methyl chloride, organic solvents, synthetic estrogens and progestins, tetraethyllead, combined exposure to styrene and acetone, welding operations, and heat. The majority of reviewed papers on female fertility concerns the alterations of menstrual cycle and pregnancy complications rather than occupational exposure-induced female infertility. The literature supports the hypothesis that, in general, working women have a tendency of higher risk of unsuccessful reproductive outcomes, although the existing data are not sufficient. PMID:8243410

  15. Mecamylamine, dihydro-β-erythroidine, and dextromethorphan block conditioned responding evoked by the conditional stimulus effects of nicotine

    PubMed Central

    Struthers, Amanda M.; Wilkinson, Jamie L.; Dwoskin, Linda P.; Crooks, Peter A.; Bevins, Rick A.

    2009-01-01

    Current smokers express the desire to quit. However, the majority find it difficult to remain abstinent. As such, research efforts continually seek to develop more effective treatment. One such area of research involves the interoceptive stimulus effects of nicotine as either a discriminative stimulus in an operant drug discrimination task, or more recently as a conditional stimulus (CS) in a discriminated goal-tracking task. The present work investigated the potential role nicotinic acetylcholine receptors in the CS effects of nicotine (0.4 mg/kg) using antagonists with differential selectivity for β2*, α7*, α6β2*, and α3β4* receptors. Methyllycaconitine (MLA) had no effect on nicotine-evoked conditioned responding. Mecamylamine and dihydro-β-erythroidine (DHβE) dose dependently blocked responding evoked by the nicotine CS. In a time-course assessment of mecamylamine and DHβE, each blocked conditioned responding when given 5 min before testing and still blocked conditioned responding when administered 200 min before testing. Two novel bis-picolinium analogs (N, N’-(3, 3′-(dodecan-1,12-diyl)-bis-picolinium dibromide [bPiDDB], and N, N’-(decan-1,10-diyl)-bis-picolinium diiodide [bPiDI]) did not block nicotine-evoked conditioned responding. Finally, pretreatment with low dose combinations of mecamylamine, dextromethorphan, and/or bupropion were used to target α3β4* receptors. No combination blocked conditioned responding evoked by the training dose of nicotine. However, a combination of mecamylamine and dextromethorphan partially blocked nicotine-evoked conditioned responding to a lower dose of nicotine (0.1 mg/kg). These results indicate that β2* and potentially α3β4* nicotinic acetylcholine receptors play a role in the CS effects of nicotine and are potential targets for the development of nicotine cessation aids. PMID:19778551

  16. Bromine enrichment in marsh sediments as a marker of environmental changes driven by Grand Solar Minima and anthropogenic activity (Caminha, NW of Portugal).

    PubMed

    Moreno, J; Fatela, F; Leorri, E; Araújo, M F; Moreno, F; De la Rosa, J; Freitas, M C; Valente, T; Corbett, D R

    2015-02-15

    A sediment core collected in Caminha tidal marsh, NW Portugal, was used to assess bromine (Br) signal over the last ca. 1,700 years. The Br temporal variability reflects its close relationship with soil/sediment organic matter (OM) and also alterations in Br biogeochemical recycling in marsh environment. The highest Br enrichment in sediments was found during the Maunder Solar Minimum, a major solar event characterized by lower irradiance (TSI) and temperature, increased cloudiness and albedo. The obtained results suggest that those climate-induced changes weakened the natural mechanisms that promote Br biochemical transformations, driven by both living plants metabolism and plant litter degradation, with the ensuing generation of volatile methyl bromide (CH3Br). It seems that the prevailing climate conditions during the Maunder favoured the retention of more Br in marsh ecosystem, ultimately decreasing the biogenic Br emissions to the atmosphere. During the 20th century, the Br pattern in sediments appears to mirror likewise anthropogenic sources. The significant correlation (p<0.05) between Br/OM ratios and Pb contents in sediments after 1934 suggests a common source. This is most probably related with the rise, massive consumption and prohibition of leaded gasoline, where ethylene dibromide was added as lead scavenger to antiknock mixtures. More regionally, the concerted use of flame retardants on forest fire management, covering the 1980s through mid-1990s in the north of Portugal and Galicia, could be responsible for the observed increase of sediment Br (relatively to Pb) pool of this tidal marsh. Although man-made brominated compounds are being phased-out since the inception of the 1992 Montreal Protocol, the Caminha tidal marsh sedimentary record showed that Br levels only started to decline after 2002.

  17. Pesticide poisoning trend analysis of 13 years: a retrospective study based on telephone calls at the National Poisons Information Centre, All India Institute of Medical Sciences, New Delhi.

    PubMed

    Peshin, Sharda Shah; Srivastava, Amita; Halder, Nabanita; Gupta, Yogendra Kumar

    2014-02-01

    The study was designed to analyze the incidence and pattern of pesticide poisoning calls reported to the National Poisons Information Centre (NPIC), AIIMS, New Delhi and highlight the common classes of pesticides involved in poisoning. The telephone calls received by the Centre during the thirteen year period (1999-2012) were entered into a preset proforma and then into a retrievable database. A total of 4929 calls of pesticide poisoning were recorded. The data was analyzed with respect to age, gender, mode and type of poisoning. The age ranged from 1 to 65 years with the preponderance of males (M = 62.19%, F = 37.80%). The age group mainly involved in poisoning was 18-35 years. While 59.38% calls pertained to household pesticides, 40.61% calls related to agricultural pesticides. The common mode of poisoning was intentional (64.60%) followed by accidental (34.40%) and unknown (1%). Amongst the household pesticides, the highest number of calls were due to pyrethroids (26.23%) followed by rodenticides (17.06%), organophosphates (6.26%), carbamates (4.95%) and others (4.86%). In agricultural pesticides group, the organophosphates (9.79%) ranked the first followed by, aluminium phosphide (9.65%), organochlorines (9.31%), pyrethroids (3.87%), herbicides, weedicides and fungicides (3.20%), ethylene dibromide (2.82%), and others (1.70%). The data analysis shows a high incidence of poisoning due to household pesticides as compared to agricultural pesticides, clearly emphasizing the need for creating awareness and education about proper use and implementation of prevention programmes.

  18. Synthesis, characterization, and variable range hopping transport of pyrite (FeS₂) nanorods, nanobelts, and nanoplates.

    PubMed

    Cabán-Acevedo, Miguel; Liang, Dong; Chew, Kit S; Degrave, John P; Kaiser, Nicholas S; Jin, Song

    2013-02-26

    We report the growth, structural, and electrical characterization of single-crystalline iron pyrite (FeS₂) nanorods, nanobelts, and nanoplates synthesized via sulfidation reaction with iron dichloride (FeCl₂) and iron dibromide (FeBr₂). The as-synthesized products were confirmed to be single-crystal phase pure cubic iron pyrite using powder X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. An intermediate reaction temperature of 425 °C or a high sulfur vapor pressure under high temperatures was found to be critical for the formation of phase pure pyrite. Field effect transport measurements showed that these pyrite nanostructures appear to behave as a moderately p-doped semiconductor with an average resistivity of 2.19 ± 1.21 Ω·cm, an improved hole mobility of 0.2 cm² V⁻¹ s⁻¹, and a lower carrier concentration on the order of 10¹⁸-10¹⁹ cm⁻³ compared with previous reported pyrite nanowires. Temperature-dependent electrical transport measurements reveal Mott variable range hopping transport in the temperature range 40-220 K and transport via thermal activation of carriers with an activation energy of 100 meV above room temperature (300-400 K). Most importantly, the transport properties of the pyrite nanodevices do not change if highly pure (99.999%) precursors are utilized, suggesting that the electrical transport is dominated by intrinsic defects in pyrite. These single-crystal pyrite nanostructures are nice platforms to further study the carrier conduction mechanisms, semiconductor defect physics, and surface properties in depth, toward improving the physical properties of pyrite for efficient solar energy conversion.

  19. In vitro induction of sister chromatid exchanges and chromosomal aberrations in peripheral lymphocytes of the oyster toadfish and American eel

    SciTech Connect

    Ellingham, T.J.; Christensen, E.A.; Maddock, M.B.

    1986-01-01

    A series of experiments was conducted to characterize the proliferation of oyster toadfish lymphocytes in medium containing 5-bromodeoxyuridine (BrdUrd) and to determine the effectiveness of cytogenetic endpoints for assessing the genotoxic effects of in vitro exposure of toadfish and eel lymphocytes to known mammalian clastogens. Although the rate of proliferation of toadfish lymphocytes was low compared to that of mammalian lymphocytes, the effects of increasing BrdUrd concentrations were similar. Mitomycin C (MMC) and ethylene dibromide (EDB) induced concentration-dependent increases in chromatid-type exchange and SCE frequencies with least effective concentrations for SCE induction by MMC (6.8 x 10/sup -9/ M) and EDB (2.6 x 10/sup -4/ M) that were comparable to or slightly lower than those that have been obtained with mammalian in vitro systems. In vitro exposure of toadfish lymphocytes to dimethoate (DIM) induced a concentration-dependent increase in SCE frequency with a least effective concentration of 2.8 x 10/sup -3/ M that was much higher than that observed with mammalian in vitro systems. In vitro exposure of American eel lymphocytes to MMC also induced a concentration-dependent increase in the frequency of chromosomal aberrations and SCEs with a least effective concentration for SCE induction of 2.0 x 10/sup -9/ M. These results indicate that cytogenetic endpoints can be effectively scored with cultured lymphocytes from these and perhaps other fish species with comparable karyotypes that contain an average of at least 0.07 pg DNA/chromosome.

  20. A broadband excimer source of visible radiation with barrier discharge pumping

    NASA Astrophysics Data System (ADS)

    Malinin, A. N.; Polyak, A. V.

    2003-12-01

    We investigate the characteristics of a broadband cylindrical excimer source of visible radiation with a surface area of 230 cm2 excited by a pulse-periodic barrier discharge based on multicomponent mixtures (mercury diiodide and dibromide with helium and admixtures of molecular nitrogen and xenon). The working mixture components were excited by a pulse-periodic (pulse repetition rate 500 5000 Hz, pulse duration ˜150 ns) barrier discharge. We detected radiation from excimer HgI* and HgBr* molecules, the second positive system of molecular nitrogen, and mercury and xenon atoms. The amplitude, duration, and trailing edge of the radiation pulses in the HgI2:HgBr2:Xe:He and HgI2: HgBr2:N2:He mixtures with admixtures of xenon and molecular nitrogen were found to change compared to the HgI2:HgBr2:He mixture. The optimal partial pressure of helium lies within the range 162 195 kPa. The most intense radiation from HgI* and HgBr* molecules (in a ratio of more than 3: 1) is observed in the HgI2:HgBr2: Xe:He mixture. The mean and pulse radiation powers are 45 W and 93 kW, respectively, at a pumping pulse repetition rate of 5000 Hz and an efficiency of 30%. We discuss the spectral and temporal characteristics of the radiation source and the dependence of the radiation intensity of excimer molecules of mercury monoiodide and monobromide on the partial pressures of xenon and nitrogen. We point out that the radiation source is of considerable interest for applications in biotechnology and medicine.

  1. Effect of light on self-assembly of aqueous mixtures of sodium dodecyl sulfate and a cationic, bolaform surfactant containing azobenzene.

    PubMed

    Hubbard, F Pierce; Abbott, Nicholas L

    2007-04-24

    We report light and small-angle neutron scattering measurements that characterize microstructures formed in aqueous surfactant solutions (up to 1.0 wt % surfactant) containing mixtures of sodium dodecyl sulfate (SDS) and the light-sensitive bolaform surfactant, bis(trimethylammoniumhexyloxy)azobenzene dibromide (BTHA) as a function of composition, equilibration time, and photostationary state (i.e., solutions rich in cis-BTHA or trans-BTHA). We observed formation of vesicles in both SDS-rich and trans-BTHA-rich regions of the microstructure diagram, with vesicles present over a particularly broad range of compositions for trans-BTHA-rich solutions. Illumination of mixtures of BTHA and SDS with a broadband UV light source leads to formation of photostationary states where the fraction of BTHA present as cis isomer (75-80% cis-BTHA) is largely independent of the mixing ratio of SDS and BTHA. For a relatively limited set of mixing ratios of SDS and BTHA, we observed UV illumination of SDS-rich vesicles to result in the reversible transformation of the vesicles to micellar aggregates and UV illumination of BTHA-rich vesicles to result in irreversible precipitation. Surprisingly, however, for many mixtures of trans-BTHA and SDS that formed solutions containing vesicles, illumination with UV light (which was confirmed to lead to photoisomerization of BTHA) resulted in only a small decrease in the number of vesicles in solution, relatively little change in the sizes of the remaining vesicles, and coexistance of the vesicles with micelles. These observations are consistent with a physical model in which the trans and cis isomers of BTHA present at the photostationary state tend to segregate between the different microstructures coexisting in solution (e.g., vesicles rich in trans-BTHA and SDS coexist with micelles rich in cis-BTHA and SDS). The results presented in this paper provide guidance for the design of light-tunable surfactants systems.

  2. Occurrence and potential human-health relevance of volatile organic compounds in drinking water from domestic wells in the United States

    USGS Publications Warehouse

    Rowe, B.L.; Toccalino, P.L.; Moran, M.J.; Zogorski, J.S.; Price, C.V.

    2011-01-01

    BACKGROUND: As the population and demand for safe drinking water from domestic wells increase, it is important to examine water quality and contaminant occurrence. A national assessment in 2006 by the U.S. Geological Survey reported findings for 55 volatile organic compounds (VOCs) based on 2,401 domestic wells sampled during 1985-2002. OBJECTIVES: We examined the occurrence of individual and multiple VOCs and assessed the potential human-health relevance of VOC concentrations. We also identified hydrogeologic and anthropogenic variables that influence the probability of VOC occurrence. METHODS: The domestic well samples were collected at the wellhead before treatment of water and analyzed for 55 VOCs. Results were used to examine VOC occurrence and identify associations of multiple explanatory variables using logistic regression analyses. We used a screening-level assessment to compare VOC concentrations to U.S. Environmental Protection Agency maximum contaminant levels (MCLs) and health-based screening levels. RESULTS: We detected VOCs in 65% of the samples; about one-half of these samples contained VOC mixtures. Frequently detected VOCs included chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene. VOC concentrations generally were < 1 ??g/L. One or more VOC concentrations were greater than MCLs in 1.2% of samples, including dibromochloropropane, 1,2-dichloropropane, and ethylene dibromide (fumigants); perchloroethene and trichloroethene (solvents); and 1,1-dichloroethene (organic synthesis compound). CONCLUSIONS: Drinking water supplied by domestic wells is vulnerable to low-level VOC contamination. About 1% of samples had concentrations of potential human-health concern. Identifying factors associated with VOC occurrence may aid in understanding the sources, transport, and fate of VOCs in groundwater.

  3. Effect of diquat on the antioxidant system and cell growth in human neuroblastoma cells.

    PubMed

    Slaughter, Mark R; Thakkar, Hansa; O'Brien, Peter J

    2002-01-15

    Oxidative stress elicits an adaptive antioxidant response, which varies with tissue type. Diquat, a potent redox cycler that generates reactive oxygen species, has been used to study oxidative stress; however, its effect on the antioxidant system has not been characterized in neuronal cells. Accordingly, we measured antioxidant parameters and cell growth in human neuroblastoma SH-SY5Y cells cultured for 48 h in medium containing 5, 10, or 25 microM diquat dibromide or phosphate-buffered saline. Viable cells were assayed for glutathione (GSH) and activities of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPX), and glucose-6-phosphate dehydrogenase (GPDH). Mitochondrial function was evaluated by glutamate dehydrogenase (GDH) activity and MTT reduction. Diquat caused a marked concentration-related decrease in viable cell count ( by 26, 51, and 87% at 5, 10, and 25 microM diquat). Cell viability was only affected at 10 and 25 microM diquat and did not fully account for the decreased viable cell count. Concentration-related increases also occurred with GSH levels and a majority of antioxidant enzymes activities; however, the mode and magnitude varied with parameter. Increases in GSH, CAT, SOD, and GR were maximal at 25 microM diquat (to 3-, 6-, 2-, and 1.5-fold control values, respectively). GPDH activity was maximal at 10 microM diquat and then decreased to 86% of control activity at 25 microM diquat. GPX activity showed a concentration-related decrease (to 35% of control). Activity of the mitochondrial enzyme GDH increased 3-fold at 25 microM diquat, along with a lesser increase in MTT reduction. We conclude that diquat reduces cell growth in neuroblastoma cells and induces an adaptive antioxidant response, which are concentration dependent and occur at sublethal concentrations. At higher concentrations, diquat alters mitochondrial function and becomes increasingly toxic. ©2002 Elsevier Science (USA).

  4. Effects of diquat, an aquatic herbicide, on the development of mallard embryos.

    PubMed

    Sewalk, C J; Brewer, G L; Hoffman, D J

    2001-01-12

    Bipyridylium herbicides produce embryotoxic and teratogenic effects in dipteran, amphibian, avian, and mammalian organisms. Diquat dibromide, a bipyridylium compound, is commonly used as an aquatic herbicide. Mallard (Anas platyrhynchos) eggs were exposed to diquat by immersing the eggs for 10 s in solutions of 0.88, 3.5, 7, 14, or 56 g/L on either d 4 or 21 of incubation. Application of diquat on d 4 yielded an estimated LC50 of 19.5 g/L through 18 d of incubation, and 9.6 g/L through hatching. Body and organ weights, and bone lengths of hatchlings did not differ between control and treatment groups with the exception of a slight increase in brain weight in the 14 g/L group. Malformations in diquat-treated embryos included defects of the brain, eye, bill, limb, and pelvis; skeletal scoliosis; and incomplete ossification. Subcutaneous edema was also present. Significant manifestations of oxidative stress were apparent in hatchlings and included increased hepatic thiobarbituric acid-reactive substances (TBARS) (lipid peroxidation) and decreased brain reduced glutathione (GSH). Brain protein-bound sulfhydryls (PBSH) increased. Diquat applied on d 21 of incubation yielded an estimated LC50 of 12.6 g/L through hatching. Exposure at this late stage of development did not produce deformities. Body and organ weights and, bone lengths of hatchlings did not differ between control and treatment groups. Significant manifestations of oxidative stress in hatchlings included decreased brain GSH, increased oxidized glutathione (GSSG), and ratio of GSSG to GSH. This study suggests that concentrations of diquat commonly used for aquatic weed control, when based upon the dilution effect of average water depth of the application area, would probably have little impact on mallard embryos. However, concentrations applied above ground to weeds and cattails along ditches could adversely affect the survival and development of mallard embryos, and presumably other avian species nesting in

  5. Nrf2 protects against diquat-induced liver and lung injury.

    PubMed

    Wu, Kai Connie; Zhang, Youcai; Klaassen, Curtis D

    2012-10-01

    Diquat is an herbicide that generates superoxide anions through redox cycling. Nuclear factor erythroid-derived 2- like 2 (Nrf2) is a transcription factor that up-regulates cytoprotective genes in response to oxidative stress. To investigate the protective effect of Nrf2 against diquat-induced toxicity, wild-type, Nrf2-null and Kelch-like ECH-associated protein 1-knockdown (Keap1-KD) mice with enhanced Nrf2 activity were treated with diquat dibromide (125 mg/kg, i.p.). Blood and tissues were collected at 1, 2, 4 and 6 hours after treatment. Administration of diquat resulted in lipid peroxidation and lethality in wild-type mice, which were more in Nrf2-null mice and less in Keap1-KD mice. Diquat produced liver injury in Nrf2-null mice, as evidenced by increased serum ALT activity and extensive hepatic necrosis, but not in wild-type and Keap1-KD mice. Diquat produced more severe lung injury in Nrf2-null than in wild-type mice, as evidenced by increased lung weight and alveolar collapse. In contrast, Keap1-KD mice had attenuated lung edema and no histopathological alterations. To further investigate the mechanism of the protective effects of Nrf2, lung and liver glutathione (GSH) concentrations were quantified. Diquat decreased GSH in lung and liver in wild-type mice, and the decrease was more in Nrf2-null mice, and less in Keap1-KD mice. After diquat treatment, the mRNA of the GSH synthesis enzyme Gclc was increased in Keap1-KD, but not in Nrf2-null mice. Collectively, Nrf2 plays an important role in preventing diquat-induced liver and lung injury, and this protective effect results from Nrf2-regulated elevation of cellular GSH and expression of GSH synthetic genes.

  6. Nrf2 regulates an adaptive response protecting against oxidative damage following diquat-mediated formation of superoxide anion.

    PubMed

    Osburn, William O; Wakabayashi, Nobunao; Misra, Vikas; Nilles, Tricia; Biswal, Shyam; Trush, Michael A; Kensler, Thomas W

    2006-10-01

    Mouse embryonic fibroblasts derived from Nrf2-/- mice (N0) and Nrf2+/+ mice (WT) have been used to characterize both basal and diquat (DQ)-induced oxidative stress levels and to examine Nrf2 activation during exposure to DQ-generated superoxide anion. Microarray analysis revealed that N0 cells have similar constitutive mRNA expression of genes responsible for the direct metabolism of reactive oxygen species but decreased expression of genes responsible for the production of reducing equivalents, repair of oxidized proteins and defense against lipid peroxidation, compared to WT cells. Nonetheless, the basal levels of ROS flux and oxidative damage biomarkers in WT and N0 cells were not different. Diquat dibromide (DQ), a non-electrophilic redox cycling bipyridylium herbicide, was used to generate intracellular superoxide anion. Isolated mitochondria from both cell lines exposed to DQ produced equivalent amounts of ROS, indicating a similar cellular capacity to generate ROS. However, N0 cells exposed to DQ for 24-h exhibited markedly decreased cell viability and aconitase activity as well as increased lipid peroxidation and glutathione oxidation, relative to WT cells. 2',7'-Dichlorofluorescein fluorescence was not increased in WT and N0 cells after 30-min of DQ exposure. However, increased levels of ROS were detected in N0 cells but not WT cells after 13-h of DQ treatment. Additionally, total glutathione concentrations increased in WT, but not N0 cells following a 24-h exposure to DQ. DQ exposure resulted in activation of an antioxidant response element-luciferase reporter gene, as well as induction of Nrf2-regulated genes in WT, but not N0 cells. Thus the enhanced sensitivity of N0 cells does not reflect basal differences in antioxidative capacity, but rather an impaired ability to mount an adaptive response to sustained oxidative stress.

  7. Nrf2 Regulates an Adaptive Response Protecting Against Oxidative Damage Following Diquat-Mediated Formation of Superoxide Anion

    PubMed Central

    Osburn, William O.; Wakabayashi, Nobunao; Misra, Vikas; Nilles, Tricia; Biswal, Shyam; Trush, Michael A.; Kensler, Thomas W.

    2006-01-01

    Mouse embryonic fibroblasts derived from Nrf2 −/− mice (N0) and Nrf2 +/+ mice (WT) have been used to characterize both basal and diquat (DQ)-induced oxidative stress levels and to examine Nrf2 activation during exposure to DQ-generated superoxide anion. Microarray analysis revealed that N0 cells have similar constitutive mRNA expression of genes responsible for the direct metabolism of reactive oxygen species but decreased expression of genes responsible for the production of reducing equivalents, repair of oxidized proteins and defense against lipid peroxidation, compared to WT cells. Nonetheless, the basal levels of ROS flux and oxidative damage biomarkers in WT and N0 cells were not different. Diquat dibromide (DQ), a non-electrophilic redox cycling bipyridylium herbicide, was used to generate intracellular superoxide anion. Isolated mitochondria from both cell lines exposed to DQ produced equivalent amounts of ROS, indicating a similar cellular capacity to generate ROS. However, N0 cells exposed to DQ for 24-hr exhibited markedly decreased cell viability and aconitase activity as well as increased lipid peroxidation and glutathione oxidation, relative to WT cells. 2′,7′-Dichlorofluorescein fluorescence was not increased in WT and N0 cells after 30-min of DQ exposure. However, increased levels of ROS were detected in N0 cells but not WT cells after 13-hr of DQ treatment. Additionally, total glutathione concentrations increased in WT, but not N0 cells following a 24-hr exposure to DQ. DQ exposure resulted in activation of an antioxidant response element-luciferase reporter gene, as well as induction of Nrf2-regulated genes in WT, but not N0 cells. Thus the enhanced sensitivity of N0 cells does not reflect basal differences in antioxidative capacity, but rather an impaired ability to mount an adaptive response to sustained oxidative stress. PMID:16962985

  8. Diquat-induced cytotoxicity on Vero and HeLa cell lines: effect of melatonin and dihydromelatonin.

    PubMed

    Moravčík, Roman; Okuliarová, Monika; Kováčová, Elena; Zeman, Michal

    2014-12-01

    Diquat dibromide is a moderately toxic contact herbicide belonging to the bipyridyl group of redox-active compounds that induce a strong oxidative damage. Melatonin (MEL) can protect against oxidative damage under in vivo conditions, probably through its anti-oxidative capacity and ability to induce expression of anti-oxidative enzymes. The objective of this study was to investigate effects of diquat on viability of Vero and HeLa cells and possible protective effects of MEL and its analogue 2,3-dihydromelatonin (DMEL). Cell viability was evaluated with the MTT test. First, we analyzed dose-dependent effects of diquat on cell viability using the concentration range of 0.1-100 μM. Second, we used the diquat dose which reduced cell viability by 50% and treated cells with either MEL or DMEL (both in the concentration range of 1-100 μM) in the presence or absence of diquat. In addition, effects of both diquat and MEL on oxidative stress in HeLa cells were measured by flow cytometry using 2',7'-dichlorofluorescin diacetate. We confirmed the expected negative effects of diquat on viability of Vero and HeLa cells. Melatonin and DMEL were able to prevent diquat reduced viability of Vero cells in rather low concentrations (1 μM) and DMEL exerted substantially stronger protective effects than MEL. However in HeLa cells, we did not find the same effects and MEL even reduced their viability. Moreover, treatment of HeLa cells with high concentrations of MEL (100 μM) exaggerated the pro-oxidative effects of diquat. The results suggest that in addition to the expected anti-oxidative effects, MEL exerts a pro-oxidative action which is cell type and dose dependent.

  9. Isotopic Signature Transfer and Mass Pattern Prediction (IsoStamp): An Enabling Technique for Chemically-Directed Proteomics

    PubMed Central

    2011-01-01

    Directed proteomics applies mass spectrometry analysis to a subset of information-rich proteins. Here we describe a method for targeting select proteins by chemical modification with a tag that imparts a distinct isotopic signature detectable in a full-scan mass spectrum. Termed isotopic signature transfer and mass pattern prediction (IsoStamp), the technique exploits the perturbing effects of a dibrominated chemical tag on a peptide’s mass envelope, which can be detected with high sensitivity and fidelity using a computational method. Applying IsoStamp, we were able to detect femtomole quantities of a single tagged protein from total mammalian cell lysates at signal-to-noise ratios as low as 2.5:1. To identify a tagged-peptide’s sequence, we performed an inclusion list-driven shotgun proteomics experiment where peptides bearing a recoded mass envelope were targeted for fragmentation, allowing for direct site mapping. Using this approach, femtomole quantities of several targeted peptides were identified in total mammalian cell lysate, while traditional data-dependent methods were unable to identify as many peptides. Additionally, the isotopic signature imparted by the dibromide tag was detectable on a 12-kDa protein, suggesting applications in identifying large peptide fragments, such as those containing multiple or large posttranslational modifications (e.g., glycosylation). IsoStamp has the potential to enhance any proteomics platform that employs chemical labeling for targeted protein identification, including isotope coded affinity tagging, isobaric tagging for relative and absolute quantitation, and chemical tagging strategies for posttranslational modification. PMID:21604797

  10. Biofilm prevention by dicephalic cationic surfactants and their interactions with DNA.

    PubMed

    Piecuch, A; Lamch, Ł; Paluch, E; Obłąk, E; Wilk, K A

    2016-09-01

    The studies were aimed to contribute to the elucidation of the relationships between structure of the double-headed cationic surfactants-N,N-bis[3,3'-(dimethylamine)- propyl]alkylamide dihydrochlorides and N,N-bis[3,3'-(trimethylammonio)propyl]alkylamide dibromides (alkyl: n-C9 H19 , n-C11 H23 , n-C13 H27 , n-C15 H31 ) and their antibacterial and biofilm preventing activity. The minimal inhibitory and bactericidal concentrations (MIC and MBC) of dicephalic surfactants against Staphylococcus epidermidis and Pseudomonas aeruginosa were tested using standard methods. Pseudomonas aeruginosa was resistant to studied compounds but MBC values against Staph. epidermidis reached 0·48-0·01 mmol l(-1) . The influence of dicephalic surfactants on bacterial biofilm and adhesion to the various surfaces was investigated with crystal violet staining or colony counting. The reduction in bacterial adhesion was observed, especially in the case of glass and stainless steel. The condensation of the DNA was shown in the ethidium bromide intercalation assay. Dicephalic surfactants exhibited antibacterial activity against Staph. epidermidis. The activity of studied compounds depended on the hydrocarbon chain length and the counterion. Surfactants deposited on different materials reduced Staph. epidermidis adhesion, dependently on the surfactant structure and the substratum. Dicephalic surfactants showed the ability of DNA compaction. This study points the possibility of application of dicephalic surfactants as the surface-coating agents to prevent biofilm formation. These compounds efficiently condensed DNA and are potential candidates for further studies towards the transfection. © 2016 The Society for Applied Microbiology.

  11. Derivation of aquatic screening benchmarks for 1,2-dibromoethane.

    PubMed

    Kszos, L A; Talmage, S S; Morris, L G W; Konetsky, B K; Rottero, T

    2003-07-01

    Ethylene dibromide (1,2-dibromoethane or EDB) was primarily used in the United States as an additive in leaded gasoline and as a soil and grain fumigant for worm and insect control until it was banned in 1983. Historical releases of EDB have resulted in detectable EDB in groundwater and drinking wells, and recently concentrations up to 16 microg/L were detected in ground water at two fuel spill plumes in the vicinity of the Massachusetts Military Reservation Base on Cape Cod, Massachusetts. Because the ground water in this area is used to flood cranberry bogs for the purposes of harvesting, the U.S. Air Force sponsored the development of aquatic screening benchmarks for EDB. Acute toxicity tests with Pimephales promelas (fathead minnow), Daphnia magna, and Ceriodaphnia dubia were conducted to provide data needed for development of screening benchmarks. Using a closed test-system to prevent volatilization of EDB, the 48-h LC50S (concentration that kills 50% of the test organisms) for P. promelas, D. magna, and C. dubia were 4.3 mg/L, 6.5 mg/L, and 3.6 mg/L, respectively. The screening benchmark for aquatic organisms, derived as the Tier II chronic water quality criteria, is 0.031 mg EDB/L. The sediment screening benchmark, based on equilibrium partitioning, is 2.45 mg EDB/kg of organic carbon in the sediment. The screening benchmarks developed here are an important component of an ecological risk assessment, during which perhaps hundreds of chemicals must be evaluated for their potential to cause ecological harm.

  12. Sorption of selected organic compounds from water to a peat soil and its humic-acid and humin fractions: Potential sources of the sorption nonlinearity

    USGS Publications Warehouse

    Chiou, C.T.; Kile, D.E.; Rutherford, D.W.; Sheng, G.; Boyd, S.A.

    2000-01-01

    The sorption isotherms of ethylene dibromide (EDB), diuron (DUN), and 3,5-dichlorophenol (DCP) from water on the humic acid and humin fractions of a peat soil and on the humic-acid of a muck soil have been measured. The data were compared with those of the solutes with the whole peat from which the humic-acid (HA) and humin (HM) fractions were derived and on which the sorption of the solutes exhibited varying extents of nonlinear capacities at low relative concentrations (C(e)/S(w)). The HA fraction as prepared by the density-fractionated method is relatively pure and presumably free of high- surface-area carbonaceous material (HSACM) that is considered to be responsible for the observed nonlinear sorption for nonpolar solutes (e.g., EDB) on the peat; conversely, the base-insoluble HM fraction as prepared is presumed to be enriched with HSACM, as manifested by the greatly higher BET- (N2) surface area than that of the whole peat. The sorption of EDB on HA exhibits no visible nonlinear effect, whereas the sorption on HM shows an enhanced nonlinearity over that on the whole peat. The sorption of polar DUN and DCP on HA and HM display nonlinear effects comparable with those on the whole peat; the effects are much more significant than those with nonpolar EDB. These results conform to the hypothesis that adsorption onto a small amount of strongly adsorbing HSACM is largely responsible for the nonlinear sorption of nonpolar solutes on soils and that additional specific interactions with the active groups of soil organic matter are responsible for the generally higher nonlinear sorption of the polar solutes.

  13. Diquat associated with copper sources for algae control: Efficacy and ecotoxicology.

    PubMed

    Garlich, Nathalia; Da Cruz, Claudinei; Da Silva, Adilson F; Carraschi, Silvia P; Malaspina, Igor C; Pitelli, Robinson A; Bianco, Silvano

    2016-01-01

    The aims of this research were to evaluate the efficacy of copper oxychloride (CuCl2.3Cu(OH)2), copper hydroxide (Cu(OH)2) and diquat (1.1'-ethylene-2.2'-bipyridyldiylium dibromide), isolated and in association with 0.1% of both copper sources, in the control of the unicellular algae Ankistrodesmus gracilis and the filamentous algae Pithophora kewesis, and to determine the acute toxicity of the tested chemicals in Hyphressobrycon eques, Pomacea canaliculata, Lemna minor and Azolla caroliniana. The efficacy was estimated by the methods of chlorophyll a and pheophytin a readings, changed into growth inhibition percentage. Both algae were exposed to the following concentrations: 0.2; 0.4; 0.8; 1.2 mg L(-1) of diquat and its association with the copper sources; and 0.1; 0.3; 0.5; 0.7; 1.0 and 1.5 mg L(-1) in the isolated applications of copper hydroxide and copper oxychloride. An untreated control was kept. The acute toxicity was estimatedby 50% lethal concentration (LC50). The copper sources were effective for A. gracilis control, at rates as high as 0.1 mg L(-1) (>95% efficacy). Isolated diquat and its association with copper hydroxide were both effective at rates as high as 0.4 mg L(-1), with 95 and 88% control efficacy, respectively. The copper oxychloride was effective at 0.2 mg L(-1), with 93% efficacy. None of the tested chemicals and associations was effective on P. kewesis control. The most sensitive non target organism to the tested chemicals was L. minor; the less sensitive was H. eques.

  14. Growth Inhibition and Apoptosis Induction by (+)-Cyanidan-3-ol in Hepatocellular Carcinoma

    PubMed Central

    Monga, Jitender; Pandit, Saurabh; Chauhan, Rajinder Singh; Chauhan, Chetan Singh; Chauhan, Shailender Singh; Sharma, Manu

    2013-01-01

    The objective of this study was to evaluate the cytotoxicity of (+)-cyanidan-3-ol (CD-3) in human hepatocellular carcinoma cell line (HepG2) and chemopreventive potential against hepatocellular carcinoma (HCC) in Balb/c mice. The HepG2 cell line was treated with CD-3 at various concentrations and the proliferation of the HepG2 cells was measure by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT), sulforhodamine B (SRB) and lactate dehydrogenase (LDH) assays. Cell apoptosis was detected by Hoechst 33258 (HO), Acridine orange/ethylene dibromide (AO/EB) staining, DNA fragmentation analysis and the apoptosis rate was detected by flow cytometry. The HCC tumor model was established in mice by injecting N-nitrosodiethylamine/carbon tetrachloride (NDEA/CCl4) and the effect of CD-3 on tumor growth in-vivo was studied. The levels of liver injury markers, tumor markers, and oxidative stress were measured. The expression levels of apoptosis-related genes in in-vitro and in vivo models were determined by RT-PCR and ELISA. The CD-3 induced cell death was considered to be apoptotic by observing the typical apoptotic morphological changes under fluorescent microscopy and DNA fragmentation analysis. Annexin V/PI assay demonstrated that apoptosis increased with increase in the concentration of CD-3. The expression levels of apoptosis-related genes that belong to bcl-2 and caspase family were increased and AP-1 and NF-κB activities were significantly suppressed by CD-3. Immunohistochemistry data revealed less localization of p53, p65 and c-jun in CD-3 treated tumors as compared to localization in NDEA/CCl4 treated tumors. Taken together, our data demonstrated that CD-3 could significantly inhibit the proliferation of HepG2 cells in-vitro and suppress HCC tumor growth in-vivo by apoptosis induction. PMID:23894334

  15. Closure report for Building 875 sump encased in concrete

    SciTech Connect

    Montemayor, W.

    1991-08-01

    This report will document the post-closure activities for the 875-R1U1 Waste-Solvent Underground Storage Tank located at Lawrence Livermore National Laboratory (LLNL), Site 300. The aforementioned tank waspreviously identified and registered with the California Water Resources Control Board as 875-31R. The underground tank system consists of a 55-gallon steel drum encased in concrete. The underground tank was used to collect dripping and spillage from the above-concrete drum rack storage area. The closure of this underground tank was permitted as Tank Identification No. 39-1945-21 by W.R. Snavely of SJCPHS-EHS. The last tank test, performed on February 1988, showed that the underground tank was leak tight. On May 1988, the sludge at the bottom of the tank was removed and disposed of as hazardous waste. The residual 1.5 inches of oily water in the tank was removed and the tank was washed with soap and water on December 11, 1989. The rinsate and residual sludge was disposed of as hazardous waste. The empty tank and the encasing concrete were extracted from the ground on November 5, 1990. No underground piping was associated with the removal of this underground tank since the tank was used to collect the dripping and spillage from the above-concrete drum rack. Three soil samples were collected in split tubes from approximately 1 foot below the bottom of the tank. The soil samples were collected and analyzed for Total Petroleum Hydrocarbon (TPH)-Gasoline, TPH-Diesel, Total Extractable Petroleum, Benzene, Toluene, Xylene, Ethyl Benzene, Tetraethyl Lead, Metals, Polychlorinated Biphenyls (PCB), and Ethylene Dibromide. Results indicated that the underground tank was leak tight. The concrete encasing was removed from the 55-gallon tank and disposed of as a municipal waste. The 55-gallon tank is currently stored at the Hazardous Waste Storage Area located in Lawrence Livermore National Laboratory, Livermore, California and is waiting as a hazardous waste.

  16. Occurrence and potential human-health relevance of volatile organic compounds in drinking water from domestic wells in the United States.

    PubMed

    Rowe, Barbara L; Toccalino, Patricia L; Moran, Michael J; Zogorski, John S; Price, Curtis V

    2007-11-01

    As the population and demand for safe drinking water from domestic wells increase, it is important to examine water quality and contaminant occurrence. A national assessment in 2006 by the U.S. Geological Survey reported findings for 55 volatile organic compounds (VOCs) based on 2,401 domestic wells sampled during 1985-2002. We examined the occurrence of individual and multiple VOCs and assessed the potential human-health relevance of VOC concentrations. We also identified hydrogeologic and anthropogenic variables that influence the probability of VOC occurrence. The domestic well samples were collected at the wellhead before treatment of water and analyzed for 55 VOCs. Results were used to examine VOC occurrence and identify associations of multiple explanatory variables using logistic regression analyses. We used a screening-level assessment to compare VOC concentrations to U.S. Environmental Protection Agency maximum contaminant levels (MCLs) and health-based screening levels. We detected VOCs in 65% of the samples; about one-half of these samples contained VOC mixtures. Frequently detected VOCs included chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene. VOC concentrations generally were < 1 microg/L. One or more VOC concentrations were greater than MCLs in 1.2% of samples, including dibromochloropropane, 1,2-dichloropropane, and ethylene dibromide (fumigants); perchloroethene and trichloroethene (solvents); and 1,1-dichloroethene (organic synthesis compound). Drinking water supplied by domestic wells is vulnerable to low-level VOC contamination. About 1% of samples had concentrations of potential human-health concern. Identifying factors associated with VOC occurrence may aid in understanding the sources, transport, and fate of VOCs in groundwater.

  17. Effects of diquat, an aquatic herbicide, on the development of mallard embryos

    USGS Publications Warehouse

    Sewalk, C.J.; Brewer, G.L.; Hoffman, D.J.

    2001-01-01

    Bipyridylium herbicides produce embryotoxic and teratogenic effects in dipteran, amphibian, avian, and mammalian organisms. Diquat dibromide, a bipyridylium compound, is commonly used as an aquatic herbicide. Mallard (Anas platyrhynchos) eggs were exposed to diquat by immersing the eggs for 10s in solutions of 0.88, 3.5, 7, 14, or 56 g/L on either the fourth or twenty-first day of incubation. Application of diquat on day 4 yielded an estimated LC50 of 19.5 g/L through 18 days of incubation, and 9.6 g/L through hatching. Body and organ weights, and bone lengths of hatchlings did not differ between control and treatment groups with the exception of a slight increase in brain weight in the 14 g/L group. Malformations in diquat-treated embryos included defects of the brain, eye, bill, limb, and pelvis; skeletal scoliosis; and incomplete ossification. Subcutaneous edema was also present. Significant manifestations of oxidative stress were apparent in hatchlings and included increased hepatic thiobarbituric acid reactive substances (TBARS) (lipid peroxidation) and decreased brain reduced glutathione (GSH). Brain protein-bound sulfhydryls (PBSH) increased. Diquat applied on day 21 of incubation yielded an estimated LC50 of 12.6 g/L through hatching. Exposure at this late stage of development did not produce deformities. Body and organ weights, and, bone lengths of hatchlings did not differ between control and treatment groups. Significant manifestations of oxidative stress in hatchlings included decreased brain GSH, increased oxidized glutathione (GSSG) and ratio of GSSG:GSH. This study suggests that concentrations of diquat commonly used for aquatic weed control, when based upon the expected dilution effect of average water depth of the application area, would probably have little impact on mallard embryos. However, concentrations applied above ground to weeds and cattails along the edge of waters and ditches could adversely affect the survival and development of mallard

  18. Chemical alternatives for soil fumigation with methyl bromide on tobacco seedbeds in nematode and weed control.

    PubMed

    Kutywayo, V

    2003-01-01

    The proposed phase out of methyl bromide necessitated the evaluation of a number of chemical alternatives to replace it. The recommended rate of application for methyl bromide, 50 g/m2 was evaluated over three years against various rates of 65% 1,3-Dichloropropene mixed with 35% chloropicrin (1,3-D/C-35); a combination of metham sodium and ethylene dibromide (EDB) and 65% 1,3-Dichloropropene (1,3-D) alone. Chloropicrin and 1,3-D have long been registered and used in Zimbabwe as individual chemicals and their combination as a single product had never been tested. 1,3-D/C-35 at 36.9 ml/m2 was as effective as methyl bromide in nematode and weed control and led to similar seed germination and seedling growth rate. A combination of EDB at 21 ml/m2 and metham sodium at 35 ml/m2 was also equally effective. The use of 1,3-D alone at 35 ml/m2 gave unsatisfactory weed control and led to a reduced seedling growth rate. Metham sodium alone at 35 ml/m2 gave comparable weed control, seed germination and seedling growth comparable with methyl bromide. However nematode control evaluated using a gall rating scale was reduced. 1,3-D/C-35 at 36.9 ml/m2 and metham sodium at 35 ml/m2 used in combination with EDB at 21 ml/m2 are therefore, possible replacements for methyl bromide soil fumigation in tobacco seedbeds.

  19. OS048 Mitochondrial content and function in placental cells and tissuesof preeclampsia and IUGR.

    PubMed

    Mando', C; Marino, M A; Miriam, F; Palma, C De; Borelli, M; Trabattoni, D; Stampalija, T; Ferrazzi, E; Clementi, E; Cetin, I

    2012-07-01

    Early onset placenta Preeclampsia (ePE) with Intrauterine Growth Restriction (IUGR) is associated with insufficient placental function, leading to decreased nutrient and oxygen (O2) availability for the fetus [1]. Mitochondria (mt) are the cell energy producers. Mt dysfunctions could be involved in altered placental metabolism leading to ePE and IUGR. We previously demonstrated higher levels of mtDNA in human IUGR placentas [2]. Here we investigate mtDNA levels in ePE and PE without IUGR placentas, and we present an innovative technique, High Resolution Respirometry (HRR), on cytotrophoblast cells (CTC) from PE, IUGR and control placentas (C), measuring cell O2 consumption which represents respiratory chain efficiency. mtDNA was measured by Real-Time PCR in 20 PE placentas, with (n=14) or without (n=6) IUGR, and 45 C. CTC were isolated from 4 PE, 4 IUGR and 6 C and characterized by flow cytometry, staining samples with anti-cytokeratin-7 and anti-vimentin antibodies. Cells were located in chambers with atmospheric O2levels; 2 different protocols were used, with or without digitonin permeabilization, allowing to measure the O2 consumption of the respiratory chain complexes singularly or all together. Substrates and inhibitors of different respiratory chain complexes were sequentially administered (succinate, ADP, oligomycin, FCCP, rotenone, antimycin A, glutamate, malate, myxothiazol, TMPD, ascorbate, pyruvate, cytochrome C, differently combined depending on the protocol) and O2 consumption levels were recorded. Data were normalized by Citrate Synthase (CS) activity and CTC mtDNA content. PE placentas: mtDNA content was significantly increased in ePE+IUGR (p=0.02) vs C; opposite to this, mtDNA was decreased in PE without IUGR (p=0.03). CTC: single mt O2 consumption (obtained by normalizing data both by CS activity and mtDNA) was slightly increased both in PE and IUGR. The global cell respiration was increased, though not significantly. The trend towards higher O2

  20. ALDEHYDE AND OTHER VOLATILE ORGANIC CHEMICAL EMISSIONS IN FOUR FEMA TEMPORARY HOUSING UNITS ? FINAL REPORT

    SciTech Connect

    Salazar, Olivia; Maddalena, Randy L.; Russell, Marion; Sullivan, Douglas P.; Apte, Michael G.

    2008-05-04

    Four unoccupied FEMA temporary housing units (THUs) were studied to assess their indoor emissions of volatile organic compounds including formaldehyde. Measurement of whole-THU VOC and aldehyde emission factors (mu g h-1 per m2 of floor area) for each of the four THUs were made at FEMA's Purvis MS staging yard using a mass balance approach. Measurements were made in the morning, and again in the afternoon in each THU. Steady-state indoor formaldehyde concentrations ranged from 378 mu g m-3 (0.31ppm) to 632 mu g m-3 (0.52 ppm) in the AM, and from 433 mu g m-3 (0.35 ppm) to 926 mu g m-3 (0.78 ppm) in the PM. THU air exchange rates ranged from 0.15 h-1 to 0.39 h-1. A total of 45 small (approximately 0.025 m2) samples of surface material, 16 types, were collected directly from the four THUs and shipped to Lawrence Berkeley Laboratory. The material samples were analyzed for VOC and aldehyde emissions in small stainless steel chambers using a standard, accurate mass balance method. Quantification of VOCs was done via gas chromatography -- mass spectrometry and low molecular weight aldehydes via high performance liquid chromatography. Material specific emission factors (mu g h-1 per m2 of material) were quantified. Approximately 80 unique VOCs were tentatively identified in the THU field samples, of which forty-five were quantified either because of their toxicological significance or because their concentrations were high. Whole-trailer and material specific emission factors were calculated for 33 compounds. The THU emission factors and those from their component materials were compared against those measured from other types of housing and the materials used in their construction. Whole THU emission factors for most VOCs were typically similar to those from comparative housing. The three exceptions were exceptionally large emissions of formaldehyde and TMPD-DIB (a common plasticizer in vinyl products), and somewhat elevated for phenol. Of these three compounds

  1. Structure-activity analysis of aging and reactivation of human butyrylcholinesterase inhibited by analogues of tabun.

    PubMed

    Carletti, Eugénie; Aurbek, Nadine; Gillon, Emilie; Loiodice, Mélanie; Nicolet, Yvain; Fontecilla-Camps, Juan-Carlos; Masson, Patrick; Thiermann, Horst; Nachon, Florian; Worek, Franz

    2009-06-12

    hBChE [human BChE (butyrylcholinesterase)] naturally scavenges OPs (organophosphates). This bioscavenger is currently in Clinical Phase I for pretreatment of OP intoxication. Phosphylated ChEs (cholinesterases) can undergo a spontaneous time-dependent process called 'aging' during which the conjugate is dealkylated, leading to creation of an enzyme that cannot be reactivated. hBChE inhibited by phosphoramidates such as tabun displays a peculiar resistance to oxime-mediated reactivation. We investigated the basis of oxime resistance of phosphoramidyl-BChE conjugates by determining the kinetics of inhibition, reactivation (obidoxime {1,1'-(oxybis-methylene) bis[4-(hydroxyimino) methyl] pyridinium dichloride}, TMB-4 [1,3-trimethylene-bis(4-hydroxyiminomethylpyridinium) dibromide], HLö 7 {1-[[[4-(aminocarbonyl) pyridinio]methoxy]methyl]-2,4-bis-[(hydroxyimino)methyl] pyridinium dimethanesulfonate)}, HI-6 {1-[[[4-(aminocarbonyl) pyridinio] methoxy] methyl]-2-[(hydroxyimino)methyl]pyridinium dichloride monohydrate} and aging, and the crystal structures of hBChE inhibited by different N-monoalkyl and N,N-dialkyl tabun analogues. The refined structures of aged hBChE conjugates show that aging proceeds through O-dealkylation of the P(R) enantiomer of N,N-diethyl and N-propyl analogues, with subsequent formation of a salt bridge preventing reactivation, similarly to a previous observation made on tabun-ChE conjugates. Interestingly, the N-methyl analogue projects its amino group towards the choline-binding pocket, so that aging proceeds through deamination. This orientation results from a preference of hBChE's acyl-binding pocket for larger than 2-atoms linear substituents. The correlation between the inhibitory potency and the N-monoalkyl chain length is related to increasingly optimized interactions with the acyl-binding pocket as shown by the X-ray structures. These kinetics and X-ray data lead to a structure-activity relationship that highlights steric and electronic

  2. Final report : results of the 2007 targeted investigation at Hilton, Kansas.

    SciTech Connect

    LaFreniere, L. M.; Environmental Science Division

    2008-04-29

    The Commodity Credit Corporation (CCC), an agency of the U.S. Department of Agriculture (USDA), operated a grain storage facility in Hilton, Kansas, in 1954-1965. In 1992, carbon tetrachloride was first identified, at a concentration of 910 {micro}g/L, in groundwater from well GW01 at Hilton. This discovery occurred in association with the sale of the private grain storage facility on which well GW01 is located to the current owner, the Mid-Kansas Cooperative Association. The Kansas Department of Health and Environment conducted investigations at Hilton in 1992-1994. In 1996-1997, Argonne National Laboratory conducted Phase I and Phase II investigations on behalf of the CCC/USDA to characterize the distribution of the carbon tetrachloride contamination identified in well GW01, the stratigraphic units potentially hosting contaminant migration, and local hydrogeology in the Hilton area. The 2007 targeted investigation reported here focused specifically on the former CCC/USDA property at Hilton, west of the railroad tracks. (Until a property record search in 2005, the location of the CCC/USDA's former facility at Hilton was not known with certainty.) The objectives of the investigation, as implemented, were to (1) investigate for carbon tetrachloride contamination in the shallower soil and shallow aquifer units below the former CCC/USDA property and (2) investigate groundwater flow patterns. The key results of the 2007 targeted investigation are as follows: (1) No carbon tetrachloride or chloroform contamination was found in soil or groundwater below the former CCC/USDA facility. (2) The 2007 groundwater level data support a southwesterly direction for groundwater flow in the main Hilton aquifer (Equus Beds), consistent with findings of previous investigations. Contaminated well GW01 was confirmed to be upgradient from the former CCC/USDA facility. (3) The contaminants carbon tetrachloride, chloroform, and 1,2-dibromoethane (ethylene dibromide) were found in

  3. Pharmacologically Distinct Nicotinic Acetylcholine Receptors Drive Efferent-Mediated Excitation in Calyx-Bearing Vestibular Afferents

    PubMed Central

    Kewin, Kevin; Jordan, Paivi M.; Cameron, Peter; Klapczynski, Marcin; McIntosh, J. Michael; Crooks, Peter A.; Dwoskin, Linda P.; Lysakowski, Anna

    2015-01-01

    Electrical stimulation of vestibular efferent neurons rapidly excites the resting discharge of calyx/dimorphic (CD) afferents. In turtle, this excitation arises when acetylcholine (ACh), released from efferent terminals, directly depolarizes calyceal endings by activating nicotinic ACh receptors (nAChRs). Although molecular biological data from the peripheral vestibular system implicate most of the known nAChR subunits, specific information about those contributing to efferent-mediated excitation of CD afferents is lacking. We sought to identify the nAChR subunits that underlie the rapid excitation of CD afferents and whether they differ from α9α10 nAChRs on type II hair cells that drive efferent-mediated inhibition in adjacent bouton afferents. We recorded from CD and bouton afferents innervating the turtle posterior crista during electrical stimulation of vestibular efferents while applying several subtype-selective nAChR agonists and antagonists. The α9α10 nAChR antagonists, α-bungarotoxin and α-conotoxin RgIA, blocked efferent-mediated inhibition in bouton afferents while leaving efferent-mediated excitation in CD units largely intact. Conversely, 5-iodo-A-85380, sazetidine-A, varenicline, α-conotoxin MII, and bPiDDB (N,N-dodecane-1,12-diyl-bis-3-picolinium dibromide) blocked efferent-mediated excitation in CD afferents without affecting efferent-mediated inhibition in bouton afferents. This pharmacological profile suggested that calyceal nAChRs contain α6 and β2, but not α9, nAChR subunits. Selective blockade of efferent-mediated excitation in CD afferents distinguished dimorphic from calyx afferents by revealing type II hair cell input. Dimorphic afferents differed in having higher mean discharge rates and a mean efferent-mediated excitation that was smaller in amplitude yet longer in duration. Molecular biological data demonstrated the expression of α9 in turtle hair cells and α4 and β2 in associated vestibular ganglia. PMID:25716861

  4. In silico studies on the role of mutant Y337A to reactivate tabun inhibited mAChE with K048.

    PubMed

    Chandar, Nellore Bhanu; Ghosh, Shibaji; Lo, Rabindranath; Banjo, Semire; Ganguly, Bishwajit

    2015-12-05

    Organophosphorus compound (OP) tabun is resistant to reactivate by many oxime drugs after the formation of OP-conjugate with AChE. The reactivation of tabun-inhibited mAChE and site-directed mutants by bispyridinium oxime, K048 (N-[4-(4-hydroxyiminomethylpyridinio)butyl]-4-carbamoylpyridinium dibromide) showed that the mutations significantly poor the overall reactivation efficacy of K048. We have unravelled the lowered efficacy of K048 with the tabun-mutant mAChE(Y337A) using docking and steered molecular dynamics (SMD) simulations. The computed results showed some interesting features for the interaction of drug molecule K048 with tabun-mAChE(wild-type) and tabun-mutant mAChE(Y337A). The SMD simulations showed that the active pyridinium ring of K048 is directed towards the phosphorus atom conjugated to the active serine (SUN203) of tabun-mAChE(wild-type). The cradle shaped residues Tyr337-Phe338 present in the choline binding site stabilize the active pyridinium ring of K048 with π-π interaction and the residue Trp86 involved in T-shaped cation-π interaction. However, in the case of tabun-mutant mAChE(Y337A).K048 conjugate, the replacement of aromatic Tyr337 with the aliphatic alanine unit in the choline binding site, however, loses one of the π-π interaction between the active pyridinium ring of K048 and the Tyr337. The placement of aliphatic alanine unit resulted in the displacement of the side chain of Phe338 towards the His447. Such displacement is causing the inaccessibility of the drug towards the phosphorus atom conjugated to the active serine (SUN203) of tabun-mutant mAChE(Y337A). Furthermore, the unbinding of the K048 with SMD studies showed that the active pyridinium ring of the drug undergoes a complete turn along the gorge axis and is directed away from the phosphorus atom conjugated to the active serine of the tabun-mutant mAChE(Y337A). Such effects inside the gorge of tabun-mutant mAChE(Y337A) would lower the efficacy of the drug molecule (K048

  5. Vapor intrusion risk of lead scavengers 1,2-dibromoethane (EDB) and 1,2-dichloroethane (DCA).

    PubMed

    Ma, Jie; Li, Haiyan; Spiese, Richard; Wilson, John; Yan, Guangxu; Guo, Shaohui

    2016-06-01

    Vapor intrusion of synthetic fuel additives represented a critical yet still neglected problem at sites impacted by petroleum fuel releases. This study used an advanced numerical model to simulate the vapor intrusion risk of lead scavengers 1,2-dibromoethane (ethylene dibromide, EDB) and 1,2-dichloroethane (DCA) under different site conditions. We found that simulated EDB and DCA indoor air concentrations can exceed USEPA screening level (4.7 × 10(-3) μg/m(3) for EDB and 1.1 × 10(-1) μg/m(3) for DCA) if the source concentration is high enough (is still within the concentration range found at leaking UST site). To evaluate the chance that vapor intrusion of EDB might exceed the USEPA screening levels for indoor air, the simulation results were compared to the distribution of EDB at leaking UST sites in the US. If there is no degradation of EDB or only abiotic degradation of EDB, from 15% to 37% of leaking UST sites might exceed the USEPA screening level. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the screening criteria for petroleum hydrocarbon may not provide sufficient protectiveness for fuel releases containing EDB and DCA. Based on a thorough literature review, we also compiled previous published data on the EDB and DCA groundwater source concentrations and their degradation rates. These data are valuable in evaluating EDB and DCA vapor intrusion risk. In addition, a set of refined attenuation factors based on site-specific information (e.g., soil types, source depths, and degradation rates) were provided for establishing site-specific screening criteria for EDB and DCA. Overall, this study points out that lead scavengers EDB and DCA may cause vapor intrusion problems. As more field data of EDB and DCA become available, we recommend that USEPA consider including these data in the existing PVI database and possibly revising the PVI Guidance as necessary. Copyright © 2016 Elsevier Ltd. All

  6. Comparative toxicity of sodium carbonate peroxyhydrate to freshwater organisms.

    PubMed

    Geer, Tyler D; Kinley, Ciera M; Iwinski, Kyla J; Calomeni, Alyssa J; Rodgers, John H

    2016-10-01

    Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP. Hydrogen peroxide exposures were confirmed using the I3(-) method. SCP margins of safety for these organisms were compared with published toxicity data to provide context for other commonly used algaecides and herbicides (e.g. copper formulations, endothall, and diquat dibromide). Algal responses (cell density and chlorophyll a concentrations) and animal mortality were measured after 96h aqueous exposures to SCP in laboratory-formulated water to estimate EC50 and LC50 values, as well as potency slopes. Despite a shorter test duration, M. aeruginosa was more sensitive to hydrogen peroxide as SCP (96h EC50:0.9-1.0mgL(-)(1) H2O2) than the eukaryotic alga P. subcapitata (7-d EC50:5.2-9.2mgL(-1) H2O2), indicating potential for selective control of prokaryotic algae. For the three non-target animals evaluated, measured 96-h LC50 values ranged from 1.0 to 19.7mgL(-1) H2O2. C. dubia was the most sensitive species, and the least sensitive species was P. promelas, which is not likely to be affected by concentrations of hydrogen peroxide as SCP that would be used to control noxious algae (e.g. M. aeruginosa). Based on information from peer-reviewed literature, other algaecides could be similarly selective for cyanobacteria. Of the

  7. Nephropathy associated with animal, plant, and chemical toxins in the tropics.

    PubMed

    Jha, Vivekanand; Chugh, Kirpal S

    2003-01-01

    accidental occupational exposure in industrial work places (eg, chromic acid), or after suicidal or homicidal use (eg, copper sulphate, ethylene dibromide, ethylene glycol). Late presentation and multiorgan dysfunction are associated with a high mortality. A high index of suspicion, careful history taking, and an awareness of local practices are essential for proper diagnosis and management of toxic nephropathies in the tropics.

  8. Long-Cycling Aqueous Organic Redox Flow Battery (AORFB) toward Sustainable and Safe Energy Storage.

    PubMed

    Hu, Bo; DeBruler, Camden; Rhodes, Zayn; Liu, T Leo

    2017-01-25

    Redox flow batteries (RFBs) are a viable technology to store renewable energy in the form of electricity that can be supplied to electricity grids. However, widespread implementation of traditional RFBs, such as vanadium and Zn-Br2 RFBs, is limited due to a number of challenges related to materials, including low abundance and high costs of redox-active metals, expensive separators, active material crossover, and corrosive and hazardous electrolytes. To address these challenges, we demonstrate a neutral aqueous organic redox flow battery (AORFB) technology utilizing a newly designed cathode electrolyte containing a highly water-soluble ferrocene molecule. Specifically, water-soluble (ferrocenylmethyl)trimethylammonium chloride (FcNCl, 4.0 M in H2O, 107.2 Ah/L, and 3.0 M in 2.0 NaCl, 80.4 Ah/L) and N(1)-ferrocenylmethyl-N(1),N(1),N(2),N(2),N(2)-pentamethylpropane-1,2-diaminium dibromide, (FcN2Br2, 3.1 M in H2O, 83.1 Ah/L, and 2.0 M in 2.0 M NaCl, 53.5 Ah/L) were synthesized through structural decoration of hydrophobic ferrocene with synergetic hydrophilic functionalities including an ammonium cation group and a halide anion. When paired with methyl viologen (MV) as an anolyte, resulting FcNCl/MV and FcN2Br2/MV AORFBs were operated in noncorrosive neutral NaCl supporting electrolytes using a low-cost anion-exchange membrane. These ferrocene/MV AORFBs are characterized as having high theoretical energy density (45.5 Wh/L) and excellent cycling performance from 40 to 100 mA/cm(2). Notably, the FcNCl/MV AORFBs (demonstrated at 7.0 and 9.9 Wh/L) exhibited unprecedented long cycling performance, 700 cycles at 60 mA/cm(2) with 99.99% capacity retention per cycle, and delivered power density up to 125 mW/cm(2). These AORFBs are built from earth-abundant elements and are environmentally benign, thus representing a promising choice for sustainable and safe energy storage.

  9. Interaction of a cationic gemini surfactant with DNA and with sodium poly(styrene sulphonate) at the air/water interface: a neutron reflectometry study.

    PubMed

    Vongsetskul, T; Taylor, D J F; Zhang, J; Li, P X; Thomas, R K; Penfold, J

    2009-04-07

    The interactions between a dicationic gemini surfactant with a six-hydrocarbon spacer (1,2-bis(dodecyldimethyl-ammonio)hexane dibromide, C12C6C12Br2) and anionic polyelectrolyte DNA or sodium (polystyrene sulfonate) (NaPSS) at the air/solution interface have been studied and compared using neutron reflectometry together with surface tension. In the presence of the dichained cationic gemini surfactant, DNA and NaPSS display very different adsorption behaviors. The DNA/gemini mixtures show adsorption behavior very similar to that of DNA/C12TAB mixtures, with enhanced surfactant adsorption at low concentrations and thick structured layers at higher concentrations. However, for the NaPSS/gemini mixtures the amount of gemini at the surface is reduced relative to that in the absence of NaPSS at concentrations below the cmc. These differences in adsorption behavior are attributed to differences in the molecular structure and flexibility of the two polyanions. NaPSS is relatively hydrophobic and flexible enough to form bulk-phase polymer-micelle complexes with the gemini surfactant at low surfactant concentrations, whereas the adsorption of surface complexes is much less favorable because the dications on the gemini would require adjacent bulky pendant charges on the NaPSS to be oriented toward the surface. This would force the NaPSS to bend significantly whereas it is more favorable for the NaPSS to adopt an extended conformation at the surface. Thus, surfactant is actually removed from the surface to form bulk-phase complexes. In contrast with NaPSS, DNA has a far more rigid structure, and the charges on the backbone are at fixed intervals, factors that make the formation of surface DNA-monomer complexes much more favorable than bulk-phase DNA-micelle complexes. Finally, a short-chain sample of NaPSS consisting of only five to six segments adsorbs very strongly at the surface with the gemini to form more extensive layered structures than have previously been observed

  10. Kinetics of 1,2-Dichloroethane and 1,2-Dibromoethane Biodegradation in Anaerobic Enrichment Cultures

    PubMed Central

    Yu, Rong; Peethambaram, Hari S.; Falta, Ronald W.; Verce, Matthew F.; Henderson, James K.; Bagwell, Christopher E.; Brigmon, Robin L.

    2013-01-01

    1,2-Dichloroethane (1,2-DCA) and 1,2-dibromoethane (ethylene dibromide [EDB]) contaminate groundwater at many hazardous waste sites. The objectives of this study were to measure yields, maximum specific growth rates (μ̂), and half-saturation coefficients (KS) in enrichment cultures that use 1,2-DCA and EDB as terminal electron acceptors and lactate as the electron donor and to evaluate if the presence of EDB has an effect on the kinetics of 1,2-DCA dehalogenation and vice versa. Biodegradation was evaluated at the high concentrations found at some industrial sites (>10 mg/liter) and at lower concentrations found at former leaded-gasoline sites (1.9 to 3.7 mg/liter). At higher concentrations, the Dehalococcoides yield was 1 order of magnitude higher when bacteria were grown with 1,2-DCA than when they were grown with EDB, while μ̂'s were similar for the two compounds, ranging from 0.19 to 0.52 day−1 with 1,2-DCA to 0.28 to 0.36 day−1 for EDB. KS was larger for 1,2-DCA (15 to 25 mg/liter) than for EDB (1.8 to 3.7 mg/liter). In treatments that received both compounds, EDB was always consumed first and adversely impacted the kinetics of 1,2-DCA utilization. Furthermore, 1,2-DCA dechlorination was interrupted by the addition of EDB at a concentration 100 times lower than that of the remaining 1,2-DCA; use of 1,2-DCA did not resume until the EDB level decreased close to its maximum contaminant level (MCL). In lower-concentration experiments, the preferential consumption of EDB over 1,2-DCA was confirmed; both compounds were eventually dehalogenated to their respective MCLs (5 μg/liter for 1,2-DCA, 0.05 μg/liter for EDB). The enrichment culture grown with 1,2-DCA has the advantage of a more rapid transition to 1,2-DCA after EDB is consumed. PMID:23263950

  11. bPiDI: a novel selective α6β2* nicotinic receptor antagonist and preclinical candidate treatment for nicotine abuse

    PubMed Central

    Wooters, Thomas E; Smith, Andrew M; Pivavarchyk, Marharyta; Siripurapu, Kiran B; McIntosh, J Michael; Zhang, Zhenfa; Crooks, Peter A; Bardo, Michael T; Dwoskin, Linda P

    2011-01-01

    BACKGROUND AND PURPOSE Nicotinic acetylcholine receptors (nAChRs) containing α6β2 subunits expressed by dopamine neurons regulate nicotine-evoked dopamine release. Previous results show that the α6β2* nAChR antagonist, N,N′-dodecane-1,12-diyl-bis-3-picolinium dibromide (bPiDDB) inhibits nicotine-evoked dopamine release from dorsal striatum and decreases nicotine self-administration in rats. However, overt toxicity emerged with repeated bPiDDB treatment. The current study evaluated the preclinical pharmacology of a bPiDDB analogue. EXPERIMENTAL APPROACH The C10 analogue of bPiDDB, N,N-decane-1,10-diyl-bis-3-picolinium diiodide (bPiDI), was evaluated preclinically for nAChR antagonist activity. KEY RESULTS bPiDI inhibits nicotine-evoked [3H]dopamine overflow (IC50 = 150 nM, Imax = 58%) from rat striatal slices. Schild analysis revealed a rightward shift in the nicotine concentration–response curve and surmountability with increasing nicotine concentration; however, the Schild regression slope differed significantly from 1.0, indicating surmountable allosteric inhibition. Co-exposure of maximally inhibitory concentrations of bPiDI (1 µM) and the α6β2* nAChR antagonist α-conotoxin MII (1 nM) produced inhibition not different from either antagonist alone, indicating that bPiDI acts at α6β2* nAChRs. Nicotine treatment (0.4 mg·kg−1·day−1, 10 days) increased more than 100-fold the potency of bPiDI (IC50 = 1.45 nM) to inhibit nicotine-evoked dopamine release. Acute treatment with bPiDI (1.94–5.83 µmol·kg−1, s.c.) specifically reduced nicotine self-administration relative to responding for food. Across seven daily treatments, bPiDI decreased nicotine self-administration; however, tolerance developed to the acute decrease in food-maintained responding. No observable body weight loss or lethargy was observed with repeated bPiDI. CONCLUSIONS AND IMPLICATIONS These results are consistent with the hypothesis that α6β2* nAChR antagonists have potential

  12. Silver(I) complexes of mono- and bidentate N-heterocyclic carbene ligands: synthesis, crystal structures, and in vitro antibacterial and anticancer studies.

    PubMed

    Haque, Rosenani A; Choo, Sze Yii; Budagumpi, Srinivasa; Iqbal, Muhammad Adnan; Al-Ashraf Abdullah, Amirul

    2015-01-27

    A series of benzimidazole-based N-heterocyclic carbene (NHC) proligands {1-benzyl-3-(2-methylbenzyl)-benzimidazolium bromide/hexafluorophosphate (1/4), 1,3-bis(2-methylbenzyl)-benzimidazolium bromide/hexafluorophosphate (2/5) and 1,3-bis(3-(2-methylbenzyl)-benzimidazolium-1-ylmethylbenzene dibromide/dihexafluorophosphate (3/6)} has been synthesized by the successive N-alkylation method. Ag complexes {1-benzyl-3-(2-methylbenzyl)-benzimidazol-2-ylidenesilver(I) hexafluorophosphate (7), 1,3-bis(2-methylbenzyl)-benzimidazol-2-ylidenesilver(I) hexafluorophosphate (8) and 1,3-bis(3-(2-methylbenzyl)-benzimidazol-2-ylidene)-1-ylmethylbenzene disilver(I) dihexafluorophosphate (9)} of NHC ligands have been synthesized by the treatment of benzimidazolium salts with Ag2O at mild reaction conditions. Both, NHC proligands and Ag-NHC complexes have been characterized by (1)H and (13)C{(1)H} NMR and FTIR spectroscopy and elemental analysis technique. Additionally, the structure of the NHC proligand 5 and the mononuclear Ag complexes 7 and 8 has been elucidated by the single crystal X-ray diffraction analysis. Both the complexes exhibit the same general structural motif with linear coordination geometry around the Ag centre having two NHC ligands. Preliminary in vitro antibacterial potentials of reported compounds against a Gram negative (Escherichia coli) and a Gram positive (Bacillus subtilis) bacteria evidenced the higher activity of mononuclear silver(I) complexes. The anticancer studies against the human derived colorectal cancer (HCT 116) and colorectal adenocarcinoma (HT29) cell lines using the MTT assay method, revealed the higher activity of Ag-NHC complexes. The benzimidazolium salts 4-6 and Ag-NHC complexes 7-9 displayed the following IC50 values against the HCT 116 and HT29 cell lines, respectively, 31.8 ± 1.9, 15.2 ± 1.5, 4.8 ± 0.6, 10.5 ± 1.0, 18.7 ± 1.6, 1.20 ± 0.3 and 245.0 ± 4.6, 8.7 ± 0.8, 146.1 ± 3.1, 7.6 ± 0.7, 5.5 ± 0.8, 103.0 ± 2.3 μM.

  13. Understanding the Kinetics and Spectroscopy of Photoredox Catalysis and Transition-Metal-Free Alternatives.

    PubMed

    Pitre, Spencer P; McTiernan, Christopher D; Scaiano, Juan C

    2016-06-21

    more efficient for this reaction than Ru(bpy)3Cl2, which upon further examination using transient spectroscopic techniques we were able to relate to the reductive quenching ability of the aliphatic amine. Recently we were also successful in applying methylene blue for radical trifluoromethylation reactions, which is discussed in detail. Finally, we have also demonstrated that common organic electron donors, such as α-sexithiophene, can be used in photoredox processes, which we demonstrate using the dehalogenation of vic-dibromides as a model system. This is a particularly interesting system because well-defined, long-lived intermediates allowed us to fully characterize the catalytic cycle. Once again, through an in-depth kinetic analysis we were able to gain valuable insights into our reaction mechanism, which demonstrates how powerful a tool proper kinetic analysis can be in the design and optimization of photoredox processes.

  14. Pesticide Exposure and Depression among Male Private Pesticide Applicators in the Agricultural Health Study

    PubMed Central

    Beard, John D.; Umbach, David M.; Hoppin, Jane A.; Richards, Marie; Alavanja, Michael C.R.; Blair, Aaron; Sandler, Dale P.

    2014-01-01

    Background: Pesticide exposure may be positively associated with depression. Few previous studies have considered the episodic nature of depression or examined individual pesticides. Objective: We evaluated associations between pesticide exposure and depression among male private pesticide applicators in the Agricultural Health Study. Methods: We analyzed data for 10 pesticide classes and 50 specific pesticides used by 21,208 applicators enrolled in 1993–1997 who completed a follow-up telephone interview in 2005–2010. We divided applicators who reported a physician diagnosis of depression (n = 1,702; 8%) into those who reported a previous diagnosis of depression at enrollment but not follow-up (n = 474; 28%), at both enrollment and follow-up (n = 540; 32%), and at follow-up but not enrollment (n = 688; 40%) and used polytomous logistic regression to estimate odds ratios (ORs) and 95% CIs. We used inverse probability weighting to adjust for potential confounders and to account for the exclusion of 3,315 applicators with missing covariate data and 24,619 who did not complete the follow-up interview. Results: After weighting for potential confounders, missing covariate data, and dropout, ever-use of two pesticide classes, fumigants and organochlorine insecticides, and seven individual pesticides—the fumigants aluminum phosphide and ethylene dibromide; the phenoxy herbicide (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T); the organochlorine insecticide dieldrin; and the organophosphate insecticides diazinon, malathion, and parathion—were all positively associated with depression in each case group, with ORs between 1.1 and 1.9. Conclusions: Our study supports a positive association between pesticide exposure and depression, including associations with several specific pesticides. Citation: Beard JD, Umbach DM, Hoppin JA, Richards M, Alavanja MCR, Blair A, Sandler DP, Kamel F. 2014. Pesticide exposure and depression among male private pesticide applicators in the

  15. Biomolecule-nanoparticle hybrid systems for bioelectronic applications.

    PubMed

    Willner, Itamar; Willner, Bilha; Katz, Eugenii

    2007-01-01

    Recent advances in nanobiotechnology involve the use of biomolecule-nanoparticle (NP) hybrid systems for bioelectronic applications. This is exemplified by the electrical contacting of redox enzymes by means of Au-NPs. The enzymes, glucose oxidase, GOx, and glucose dehydrogenase, GDH, are electrically contacted with the electrodes by the reconstitution of the corresponding apo-proteins on flavin adenine dinucleotide (FAD) or pyrroloquinoline quinone (PQQ)-functionalized Au-NPs (1.4 nm) associated with electrodes, respectively. Similarly, Au-NPs integrated into polyaniline in a micro-rod configuration associated with electrodes provides a high surface area matrix with superior charge transport properties for the effective electrical contacting of GOx with the electrode. A different application of biomolecule-Au-NP hybrids for bioelectronics involves the use of Au-NPs as carriers for a nucleic acid that is composed of hemin/G-quadruplex DNAzyme units and a detecting segment complementary to the analyte DNA. The functionalized Au-NPs are employed for the amplified DNA detection, and for the analysis of telomerase activity in cancer cells, using chemiluminescence as a readout signal. Biomolecule-semiconductor NP hybrid systems are used for the development of photoelectrochemical sensors and optoelectronic systems. A hybrid system consisting of acetylcholine esterase (AChE)/CdS-NPs is immobilized in a monolayer configuration on an electrode. The photocurrent generated by the system in the presence of thioacetylcholine as substrate provides a means to probe the AChE activity. The blocking of the photocurrent by 1,5-bis(4-allyldimethyl ammonium phenyl)pentane-3-one dibromide as nerve gas analog enables the photoelectrochemical analysis of AChE inhibitors. Also, the association CdS-NP/double-stranded DNA hybrid systems with a Au-electrode, and the intercalation of methylene blue into the double-stranded DNA, generates an organized nanostructure of switchable

  16. Supramolecular interactions in biologically relevant compounds. 2-Pyrazineformamide thiosemicarbazones and some products of their cyclization

    NASA Astrophysics Data System (ADS)

    Castiñeiras, Alfonso; García-Santos, Isabel; Nogueiras, Silvia; Rodríguez-González, Iria; Rodríguez-Riobó, Raúl

    2014-09-01

    Reaction of 2-cyanopyrazine with thiosemicarbazide or N-methylthiosemicarbazide afforded the (Z)-2-(amino(pyrazin-2-yl)methylene)hydrazinecarbothioamide (HPzAm4DH) and (Z)-2-(amino(pyrazin-2-yl)methylene)-N-methylhydrazine carbothioamide (HPzAm4M), respectively. (2Z,N‧E)-N‧-(4-Oxothiazolidin-2-ylidene)pyrazine-2-carbohydrazonamide (HPzAmot, 5) and (2Z,N‧E)-N‧-(3-methyl-4-oxothiazolidin-2-ylidene)pyrazine-2-carbohydrazonamide (MPzAmot, 7) have been synthesized from these thiosemicarbazones with chloroacetic or bromoacetic acids, using a conventional synthetic methodology and microwave-assisted organic reaction enhancement. The crystal structures of the thiosemicarbazones and their solvates [HPzAm4DHṡ1/2 MeOH (1), HPzAm4DHṡH2O (2), HPzAm4M (3), HPzAm4Mṡ2H2O (4)] and the 1,3-thiazolidin-4-ones (5 and 7) have been studied by X-ray diffractometry. All of the compounds were characterized by elemental analysis, mass spectrometry, FT-IR and 1H and 13C NMR spectroscopy. Several by-products have also been isolated in a crystalline form, namely 3-((Z,E)-N‧-(4-oxothiazolidin-2-ylidene)carbamohydrazonium-yl)pyrazin-1-ium dibromide monohydrate, (H3PzAmot)Br2ṡH2O (6), 2-((5-(pyrazin-2-yl)-1H-1,2,4-triazol-3-yl)thio)acetic acid, (H2Pz124ttAc) (8), 2-amino-5-(pyrazin-2-yl)-1,3,4-thiadiazol-3-ium chloride monohydrate, (HPz134tda)ClṡH2O (9), and 2-(methylamino)-5-(pyrazin-2-yl)-1,3,4-thiadiazol-3-ium chloride N-methyl-5-(pyrazin-2-yl)-1,3,4-thiadiazol-2-amine solvate, (HMPz134tda)Clṡ(MPz134tda) (10). The structures of these compounds were also analyzed by X-ray diffractometry. The microwave-assisted organic reaction method for synthesis is easy, convenient, and ecofriendly when compared to the traditional synthetic methods. Crystal analysis revealed that the compounds have extended 3D supramolecular networks through high levels of H-bonding and weak molecular interactions between the molecular moieties and solvent molecules. The novel synthons, which are

  17. Easy access to silicon(0) and silicon(II) compounds.

    PubMed

    Mondal, Kartik Chandra; Samuel, Prinson P; Tretiakov, Mykyta; Singh, Amit Pratap; Roesky, Herbert W; Stückl, A Claudia; Niepötter, Benedikt; Carl, Elena; Wolf, Hilke; Herbst-Irmer, Regine; Stalke, Dietmar

    2013-04-15

    Two different synthetic methodologies of silicon dihalide bridged biradicals of the general formula (L(n)•)2SiX2 (n = 1, 2) have been developed. First, the metathesis reaction between NHC:SiX2 and L(n): (L(n): = cyclic akyl(amino) carbene in a 1:3 molar ratio leads to the products 2 (n = 1, X = Cl), 4 (n = 2, X = Cl), 6 (n = 1, X = Br), and 7 (n = 2, X = Br). These reactions also produce coupled NHCs (3, 5) under C-C bond formation. The formation of the coupled NHCs (L(m) = cyclic alkyl(amino) carbene substituted N-heterocyclic carbene; m = 3, n = 1 (3) and m = 4, n =2 (5)) is faster during the metathesis reaction between NHC:SiBr2 and L(n): when compared with that of NHC:SiCl2. Second, the reaction of L(1):SiCl4 (8) (L(1): =:C(CH2)(CMe2)2N-2,6-iPr2C6H3) with a non-nucleophilic base LiN(iPr)2 in a 1:1 molar ratio shows an unprecedented methodology for the synthesis of the biradical (L(1)•)2SiCl2 (2). The blue blocks of silicon dichloride bridged biradicals (2, 4) are stable for more than six months under an inert atmosphere and in air for one week. Compounds 2 and 4 melt in the temperature range of 185 to 195 °C. The dibromide (6, 7) analogue is more prone to decomposition in the solution but comparatively more stable in the solid state than in the solution. Decomposition of the products has been observed in the UV-vis spectra. Moreover, compounds 2 and 4 were further converted to stable singlet biradicaloid dicarbene-coordinated (L(n):)2Si(0) (n = 1 (9), 2 (10)) under KC8 reduction. Compounds 2 and 4 were also reduced to dehalogenated products 9 and 10, respectively when treated with RLi (R = Ph, Me, tBu). Cyclic voltametry measurements show that 10 can irreversibly undergo both one electron oxidation and reduction.

  18. Evaluation of estrogenic activities of aquatic herbicides and surfactants using an rainbow trout vitellogenin assay.

    PubMed

    Xie, Lingtian; Thrippleton, Kelly; Irwin, Mary Ann; Siemering, Geoffrey S; Mekebri, Abdou; Crane, David; Berry, Kevin; Schlenk, Daniel

    2005-10-01

    Estrogenic potencies of four herbicides (triclopyr, 2,4-dichlorophenoxyacetic acid (2,4-D), diquat dibromide, glyphosate), two alkylphenol ethoxylate-containing surfactants (R-11 and Target Prospreader Activator (TPA)), and the binary mixture of surfactants with the herbicides were evaluated using an in vivo rainbow trout vitellogenin assay. Juvenile rainbow trout exposed to 2,4-D (1.64 mg/l) for 7 days had a 93-fold increase in plasma vitellogenin (Vtg) levels compared with untreated fish, while rainbow trout exposed to other pesticides alone did not show elevated vitellogenin levels compared to the control fish. When combined with surfactants, trends indicated enhanced estrogenicity for all combinations, but only 2,4-D and triclopyr caused significant induction of Vtg. Concentration-response studies demonstrated that the lowest observed effect concentrations (LOECs) for 2,4-D and triclopyr were 0.164 mg/l and 1 mg/l, respectively. In terms of measured 4-nonylphenol (4-NP), the LOECs of R-11 and TPA were 20 micro/l and 9.5 microg/l, respectively. Binary mixtures of TPA and 2,4-D showed a greater than additive estrogenic response at the lowest concentrations tested, but a less than additive response at the highest combined concentrations. Binary mixtures of TPA with triclopyr also caused greater than additive Vtg responses in two middle concentrations when compared to TPA or triclopyr alone. When trout were exposed to water collected from a site where triclopyr was used in combination with TPA, a concentration-dependent increase in Vtg expression was observed. Measured values of 4-NP were 3.7 microg/l, and triclopyr concentrations were below detection (<5 ng/l). Estradiol equivalents (EEQs) of the lake water were calculated from an estradiol concentration-response curve and were similar (8.5 +/- 7.7 ng/l) to the mean values for the combined triclopyr + TPA treatments (9.9-12.2 ng/l) in the laboratory, suggesting the estrogenicity of the water may have been due to

  19. Cation siting in low-silica zeolites with potential applications in pressure swing adsorption technology and structural studies of novel tectosilicates

    NASA Astrophysics Data System (ADS)

    Burton, Allen Wayne

    prepared in the presence of tetramethylene bis(N-methylpyrrolidinium) dibromide. The structure solution of MCM-47 shows it is composed of noncovalently bound layers. The structure refinement and 1H MAS NMR experiment indicate these layers are bound together by strong hydrogen bonds between siloxy and silanol groups. MCM-47 can be delaminated to yield a high surface area material with potential applications in the catalysis of large molecules.

  20. Endothelial Cell-Surface Gp60 Activates Vesicle Formation and Trafficking via Gi-Coupled Src Kinase Signaling Pathway

    PubMed Central

    Minshall, Richard D.; Tiruppathi, Chinnaswamy; Vogel, Stephen M.; Niles, Walter D.; Gilchrist, Annette; Hamm, Heidi E.; Malik, Asrar B.

    2000-01-01

    We tested the hypothesis that the albumin-docking protein gp60, which is localized in caveolae, couples to the heterotrimeric GTP binding protein Gi, and thereby activates plasmalemmal vesicle formation and the directed migration of vesicles in endothelial cells (ECs). We used the water-soluble styryl pyridinium dye N-(3-triethylaminopropyl)-4-(p-dibutylaminostyryl) pyridinium dibromide (FM 1-43) to quantify vesicle trafficking by confocal and digital fluorescence microscopy. FM 1-43 and fluorescently labeled anti-gp60 antibody (Ab) were colocalized in endocytic vesicles within 5 min of gp60 activation. Vesicles migrated to the basolateral surface where they released FM 1-43, the fluid phase styryl probe. FM 1-43 fluorescence disappeared from the basolateral EC surface without the loss of anti-gp60 Ab fluorescence. Activation of cell-surface gp60 by cross-linking (using anti-gp60 Ab and secondary Ab) in EC grown on microporous filters increased transendothelial 125I-albumin permeability without altering liquid permeability (hydraulic conductivity), thus, indicating the dissociation of hydraulic conductivity from the albumin permeability pathway. The findings that the sterol-binding agent, filipin, prevented gp60-activated vesicle formation and that caveolin-1 and gp60 were colocalized in vesicles suggest the caveolar origin of endocytic vesicles. Pertussis toxin pretreatment and expression of the dominant negative construct encoding an 11–amino acid Gαi carboxyl-terminal peptide inhibited endothelial 125I-albumin endocytosis and vesicle formation induced by gp60 activation. Expression of dominant negative Src (dn-Src) and overexpression of wild-type caveolin-1 also prevented gp60-activated endocytosis. Caveolin-1 overexpression resulted in the sequestration of Gαi with the caveolin-1, whereas dn-Src inhibited Gαi binding to caveolin-1. Thus, vesicle formation induced by gp60 and migration of vesicles to the basolateral membrane requires the interaction of gp60

  1. The Arabidopsis apyrase AtAPY1 is localized in the Golgi instead of the extracellular space

    PubMed Central

    2012-01-01

    Background The two highly similar Arabidopsis apyrases AtAPY1 and AtAPY2 were previously shown to be involved in plant growth and development, evidently by regulating extracellular ATP signals. The subcellular localization of AtAPY1 was investigated to corroborate an extracellular function. Results Transgenic Arabidopsis lines expressing AtAPY1 fused to the SNAP-(O6-alkylguanine-DNA alkyltransferase)-tag were used for indirect immunofluorescence and AtAPY1 was detected in punctate structures within the cell. The same signal pattern was found in seedlings stably overexpressing AtAPY1-GFP by indirect immunofluorescence and live imaging. In order to identify the nature of the AtAPY1-positive structures, AtAPY1-GFP expressing seedlings were treated with the endocytic marker stain FM4-64 (N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenyl-hexatrienyl)-pyridinium dibromide) and crossed with a transgenic line expressing the trans-Golgi marker Rab E1d. Neither FM4-64 nor Rab E1d co-localized with AtAPY1. However, live imaging of transgenic Arabidopsis lines expressing AtAPY1-GFP and either the fluorescent protein-tagged Golgi marker Membrin 12, Syntaxin of plants 32 or Golgi transport 1 protein homolog showed co-localization. The Golgi localization was confirmed by immunogold labeling of AtAPY1-GFP. There was no indication of extracellular AtAPY1 by indirect immunofluorescence using antibodies against SNAP and GFP, live imaging of AtAPY1-GFP and immunogold labeling of AtAPY1-GFP. Activity assays with AtAPY1-GFP revealed GDP, UDP and IDP as substrates, but neither ATP nor ADP. To determine if AtAPY1 is a soluble or membrane protein, microsomal membranes were isolated and treated with various solubilizing agents. Only SDS and urea (not alkaline or high salt conditions) were able to release the AtAPY1 protein from microsomal membranes. Conclusions AtAPY1 is an integral Golgi protein with the substrate specificity typical for Golgi apyrases. It is therefore not likely to

  2. An epidemiological study of poisoning cases reported to the National Poisons Information Centre, All India Institute of Medical Sciences, New Delhi.

    PubMed

    Srivastava, Amita; Peshin, Sharda Shah; Kaleekal, Thomas; Gupta, Suresh Kumar

    2005-06-01

    A retrospective analysis of poisoning calls received by the National Poisons Information Centre showed a total of 2719 calls over a period of three years (April 1999-March 2002). The queries were made on poisoning management (92%) and information (8%) about various products and functioning of the centre. The data were analysed with respect to age, sex, mode and type of poisoning. The agents belonged to various groups: household products, agricultural pesticides, industrial chemicals, drugs, plants, animal bites and stings, miscellaneous and unknown groups respectively. The age ranged from less than 1 to 70 years, with the highest incidence in the range of 14-40 years, with males (57%) outnumbering females (43%). The most common mode of poisoning was suicidal (53%), followed by accidental (47%). The route of exposure was mainly oral (88%). Dermal (5%), inhalation and ocular exposure contributed 7% to the total. The highest incidence of poisoning was due to household agents (44.1%) followed by drugs (18.8%), agricultural pesticides (12.8%), industrial chemicals (8.9%), animals bites and stings (4.7%), plants (1.7%), unknown (2.9%) and miscellaneous groups (5.6%). Household products mainly comprised of pyrethroids, rodenticides, carbamates, phenyl, detergents, corrosives etc. Drugs implicated included benzodiazepines, anticonvulsants, analgesics, antihistamines, tricyclic antidepressants, thyroid hormones and oral contraceptives. Among the agricultural pesticides, aluminium phosphide was the most commonly consumed followed by organochlorines, organophosphates, ethylene dibromide, herbicides and fungicides. Copper sulphate and nitrobenzene were common among industrial chemicals. The bites and stings group comprised of snake bites, scorpion, wasp and bee stings. Poisoning due to plants was low, but datura was the most commonly ingested. An alarming feature of the study was the high incidence of poisoning in children (36.5%). The age ranged from less than 1 to 18 years

  3. Assessing the therapeutic efficacy of oxime therapies against percutaneous organophosphorus pesticide and nerve agent challenges in the Hartley guinea pig

    PubMed Central

    Snider, Thomas H.; Wilhelm, Christina M.; Babin, Michael C.; Platoff, Gennady E.; Yeung, David T.

    2016-01-01

    Given the rapid onset of symptoms from intoxication by organophosphate (OP) compounds, a quick-acting, efficacious therapeutic regimen is needed. A primary component of anti-OP therapy is an oxime reactivator to rescue OP-inhibited acetylcholinesterases. Male guinea pigs, clipped of hair, received neat applications of either VR, VX, parathion, or phorate oxon (PHO) at the 85th percentile lethal dose, and, beginning with presentation of toxicosis, received the human equivalent dose therapy by intramuscular injection with two additional follow-on treatments at 3-hr intervals. Each therapy consisted of atropine free base at 0.4 mg/kg followed by one of eight candidate oximes. Lethality rates were obtained at 24 hr after VR, VX and PHO challenges, and at 48 hr after challenge with parathion. Lethality rates among symptomatic, oxime-treated groups were compared with that of positive control (OP-challenged and atropine-only treated) guinea pigs composited across the test days. Significant (p ≤ 0.05) protective therapy was afforded by 1,1-methylene bis(4(hydroxyimino- methyl)pyridinium) dimethanesulfonate (MMB4 DMS) against challenges of VR (p ≤ 0.001) and VX (p ≤ 0.05). Lethal effects of VX were also significantly (p ≤ 0.05) mitigated by treatments with oxo-[[1-[[4-(oxoazaniumylmethylidene)pyridin-1-yl] methoxymethyl]pyridin-4-ylidene]methyl]azanium dichloride (obidoxime Cl2) and 1-(((4-(aminocarbonyl) pyridinio)methoxy)methyl)-2,4-bis((hydroxyimino)methyl)pyridinium dimethanesulfonate (HLö-7 DMS). Against parathion, significant protective therapy was afforded by obidoxime dichloride (p ≤ 0.001) and 1,1′-propane-1,3-diylbis{4-[(E)-(hydroxyimino)methyl]pyridinium} dibromide (TMB-4, p ≤ 0.01). None of the oximes evaluated was therapeutically effective against PHO. Across the spectrum of OP chemicals tested, the oximes that offered the highest level of therapy were MMB4 DMS and obidoxime dichloride. PMID:26558457

  4. Conformational properties of the acetylcholine receptor as revealed by studies with constrained depolarizing ligands

    PubMed Central

    Wassermann, N. H.; Bartels, E.; Erlanger, B. F.

    1979-01-01

    Conformational aspects of the acetylcholine receptor (AcChoR) of Electrophorus electricus have been examined by studies of its interaction with structurally related, constrained aromatic bis quaternary compounds. Among the compounds synthesized was 3,3′-bis[α-(trimethylammonium)-methyl]azobenzene dibromide (3,3′-bisQ). This compound is photochromic and can exist in a cis or trans isomeric form, both of which have now been isolated in pure form. Trans-3,3′-bisQ is the most potent activator known, producing a 60-mV depolarization at 0.2 μM and 50% activity at 0.06 μM. The cis isomer is less than 1% as active. Its high activity and constrained structure suggest that trans-3,3′-bisQ can be considered to be a “template” of the combining site of AcChoR, when the latter is in the activated state. The following conclusions can then be drawn concerning the AcChoR binding site. (i) Depolarization can occur by interaction with reagents that are essentially inflexible. (ii) The binding site has a planar hydrophobic region that interacts with methylene groups of acetylcholine and with hydrophobic areas in general. (iii) In the same plane as the hydrophobic area is a site that interacts with electron-donating functional groups including the carbonyl oxygen of acetylcholine and the azo nitrogens of trans-3,3′-bisQ. (iv) About 1.5 Å out of the plane of the hydrophobic and the electron acceptor site is an anionic site; when the AcChoR is in the activated state, this site is separated from the electron acceptor site by 5.2 Å and from another anionic site by 11 Å. (v) The anionic sites are located within a cleft of limited size, sufficient to accommodate quaternary methyl groups. (vi) Although depolarization can occur with reagents that possess only hydrophobic and cationic groups if their geometric arrangement is proper, the highest activity resides in compounds capable of all of the interactions cited above. Images PMID:284340

  5. Quality of Water from Domestic Wells in Principal Aquifers of the United States, 1991-2004

    USGS Publications Warehouse

    DeSimone, Leslie A.

    2009-01-01

    gross alpha-particle radioactivity (uncorrected) each were present at levels greater than MCLs or HBSLs in samples from about 5 to 7 percent of the wells; boron, fluoride, uranium, and gross beta-particle radioactivity were present at levels greater than MCLs or HBSLs in about 1 to 2 percent of the wells. Total coliform and Escherichia coli bacteria were detected in about 34 and 8 percent, respectively, of sampled wells. Thus, with the exception of nitrate and fecal indicator bacteria, the contaminants that were present in the sampled wells most frequently at concentrations greater than human-health benchmarks were naturally occurring. Anthropogenic organic compounds were frequently detected at low concentrations, using typical analytical detection limits of 0.001 to 0.1 micrograms per liter, but were seldom present at concentrations greater than MCLs or HBSLs. The most frequently detected compounds included the pesticide atrazine, its degradate deethylatrazine, and the volatile organic compounds chloroform, methyl tert-butyl ether, perchloroethene, and dichlorofluoromethane. Only 7 of 168 organic compounds were present in samples at concentrations greater than MCLs or HBSLs, each in less than 1 percent of wells. These were diazinon, dibromochloroprane, dinoseb, dieldrin, ethylene dibromide, perchloroethene, and trichloroethene. Overall, concentrations of any organic compound greater than MCLs or HBSLs were present in 0.8 percent of wells, and concentrations of any organic compound greater than one-tenth of MCLs or HBSLs were present in about 3 percent of wells. Several other properties and contaminants were measured at values or concentrations outside of recommended ranges for drinking water for aesthetic quality (for example, taste or odor) or other non-health reasons. About 16 percent of the sampled wells had pH values less than (14.4 percent) or greater than (1.9 percent) the USEPA recommended range of 6.5 to 8.5. Total dissolved solids were greater than th

  6. Impact of the redox-cycling herbicide diquat on transcript expression and antioxidant enzymatic activities of the freshwater snail Lymnaea stagnalis.

    PubMed

    Bouétard, Anthony; Besnard, Anne-Laure; Vassaux, Danièle; Lagadic, Laurent; Coutellec, Marie-Agnès

    2013-01-15

    The presence of pesticides in the environment results in potential unwanted effects on non-target species. Freshwater organisms inhabiting water bodies adjacent to agricultural areas, such as ditches, ponds and marshes, are good models to test such effects as various pesticides may reach these habitats through several ways, including aerial drift, run-off, and drainage. Diquat is a non-selective herbicide used for crop protection or for weed control in such water bodies. In this study, we investigated the effects of diquat on a widely spread aquatic invertebrate, the holarctic freshwater snail Lymnaea stagnalis. Due to the known redox-cycling properties of diquat, we studied transcript expression and enzymatic activities relative to oxidative and general stress in the haemolymph and gonado-digestive complex (GDC). As diquat is not persistent, snails were exposed for short times (5, 24, and 48 h) to ecologically relevant concentrations (22.2, 44.4, and 222.2 μg l(-1)) of diquat dibromide. RT-qPCR was used to quantify the transcription of genes encoding catalase (cat), a cytosolic superoxide dismutase (Cu/Zn-sod), a selenium-dependent glutathione peroxidase (gpx), a glutathione reductase (gred), the retinoid X receptor (rxr), two heat shock proteins (hsp40 and hsp70), cortactin (cor) and the two ribosomal genes r18S and r28s. Enzymatic activities of SOD, Gpx, Gred and glutathione S-transferase (GST) were investigated in the GDC using spectrophoto/fluorometric methods. Opposite trends were obtained in the haemolymph depending on the herbicide concentration. At the lowest concentration, effects were mainly observed after 24 h of exposure, with over-transcription of cor, hsp40, rxr, and sod, whereas higher concentrations down-regulated the expression of most of the studied transcripts, especially after 48 h of exposure. In the GDC, earlier responses were observed and the fold-change magnitude was generally much higher: transcription of all target genes increased

  7. Water-quality assessment of the Connecticut, Housatonic, and Thames river basins study unit; analysis of available data on nutrients, suspended sediments, and pesticides, 1972-92

    USGS Publications Warehouse

    Zimmerman, Marc James; Grady, S.J.; Trench, E.C.; Flanagan, S.M.; Nielsen, M.G.

    1996-01-01

    -water nutrient and pesticide data were compiled from several Federal and State agencies, primarily the U.S. Geological Survey, U.S. Environmental Protection Agency, and Connecticut Department of Health Services. Nutrient data were available for several thousand wells; nitrite plus nitrate as nitrogen was the most commonly reported constituent. Most wells with nutrient data are in Massachusetts and Connecticut. Relative to nutrient data in ground and surface water, pesticide data are less common. Pesticide data were available for slightly more than 200 surface-water sites and less than 500 wells; about 95 percent of the wells are completed in stratified-drift or till aquifers. Data for 81 pesticide compounds were available in various data bases. 2,4-D and silvex were the most commonly detected herbicides in surface water and dieldrin and diazinon were the most commonly detected insecticides. Most surface-water pesticide samples and detections are from bed sediment, but much of the data are not recent. Ethylene dibromide (EDB), a soil fumigant used in tobacco farming was detected in 268 well in a 50 square-mile area of north-central Connecticut; EDB contamination also was detected in wells in Massachusetts. Atrazine, an herbicide commonly used in corn farming, commonly was detected in wells installed in tilled agricultural fields. Corn herbicides were commonly detected in the northern par( of the study unit, although the sampling has been less frequent than in the southern part of the study unit. Pesticides were seldom detected in public-supply wells in Connecticut. Urban sites with relatively high population densities and high concentrations of dischargers were characterized by having the highest nutrient concentrations and loads when adjusted for differences in drainage area or population. Particularly, the Pequabuck, Naugatuck, and Quinnipiac River Basins were characterized by high nutrient concentrations--median total nitrogen concentrations ranged from 3.3 to 4.2 mg

  8. Carbene-anchored/pendent-imidazolium species as precursors to di-N-heterocyclic carbene-bridged mixed-metal complexes.

    PubMed

    Zamora, Matthew T; Ferguson, Michael J; McDonald, Robert; Cowie, Martin

    2009-09-21

    Reaction of a series of linked diimidazolium dibromide salts with one-half equivalent of [Rh(mu-OAc)(COD)](2) under reflux conditions generates a series of carbene-anchored/pendent-imidazolium complexes, [RhBr(COD)((R)C(H)-eta(1)-C(eth))][Br] ((Me)C(H)-eta(1)-C(eth) = ethylene[(N-methyl)imidazolium][(N-methyl)imidazole-2-ylidene] and (tBu)C(H)-eta(1)-C(eth) = ethylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]) via deprotonation of one end of the diimidazolium salt and coordination of the resulting carbene to Rh. Reaction of these complexes with carbon monoxide or the appropriate diphosphine yields either [RhBr(CO)(2)((R)C(H)-eta(1)-C(eth))][Br] (R = Me, (t)Bu) or [RhBr(P( intersection)P)((Me)C(H)-eta(1)-C(eth))][Br] (P( intersection)P = Ph(2)PCH(2)PPh(2), Ph(2)PCH(2)CH(2)PPh(2), Et(2)PCH(2)PEt(2)), respectively. The resulting diphosphine complexes readily decompose in solution. A series of palladium complexes [PdI(3-n)(PR(3))(n)(L)][I](n) (n = 1,2) and [PdI(P( intersection)P)(L)][I](2) (L = (tBu)C(H)-eta(1)-C(meth), (tBu)C(H)-eta(1)-C(eth); (tBu)C(H)-eta(1)-C(meth) = methylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]), containing the linked NHC-imidazolium moiety, have also been prepared by reacting the triiodo complexes, [PdI(3)((tBu)C(H)-eta(1)-C(meth))] and [PdI(3)((tBu)C(H)-eta(1)-C(eth))] with several mono- and diphosphines. Attempts to generate mixed Rh/Pd complexes using Pd(OAc)(2) to deprotonate the pendent arm of several of the above carbene-anchored/pendent-imidazolium complexes of Rh have proven unsuccessful. However, a targeted di-NHC-bridged heterobimetallic complex [PdI(2)(PEt(3))(mu-(tBu)CC(meth))RhI(COD)] ((tBu) CC(meth) = 1,1'-methylene-3,3'-di-tert-butyldiimidazol-2,2'-diylidene) can be generated by deprotonation of the imidazolium group in [PdI(2)(PEt(3))((tBu)C(H)-eta(1)-C(meth))][I] using half an equivalent of [Rh(mu-OAc)(COD)](2). The X-ray structure determination of this Pd/Rh complex confirms the