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Sample records for chlorinated lipid species

  1. Chlorinated Phospholipids and Fatty Acids: (Patho)physiological Relevance, Potential Toxicity, and Analysis of Lipid Chlorohydrins

    Science.gov (United States)

    2016-01-01

    Chlorinated phospholipids are formed by the reaction of hypochlorous acid (HOCl), generated by the enzyme myeloperoxidase under inflammatory conditions, and the unsaturated fatty acyl residues or the head group. In the first case the generated chlorohydrins are both proinflammatory and cytotoxic, thus having a significant impact on the structures of biomembranes. The latter case leads to chloramines, the properties of which are by far less well understood. Since HOCl is also widely used as a disinfecting and antibacterial agent in medicinal, industrial, and domestic applications, it may represent an additional source of danger in the case of abuse or mishandling. This review discusses the reaction behavior of in vivo generated HOCl and biomolecules like DNA, proteins, and carbohydrates but will focus on phospholipids. Not only the beneficial and pathological (toxic) effects of chlorinated lipids but also the importance of these chlorinated species is discussed. Some selected cleavage products of (chlorinated) phospholipids and plasmalogens such as lysophospholipids, (chlorinated) free fatty acids and α-chloro fatty aldehydes, which are all well known to massively contribute to inflammatory diseases associated with oxidative stress, will be also discussed. Finally, common analytical methods to study these compounds will be reviewed with focus on mass spectrometric techniques. PMID:28090245

  2. Chlorinated Phospholipids and Fatty Acids: (Pathophysiological Relevance, Potential Toxicity, and Analysis of Lipid Chlorohydrins

    Directory of Open Access Journals (Sweden)

    Jenny Schröter

    2016-01-01

    Full Text Available Chlorinated phospholipids are formed by the reaction of hypochlorous acid (HOCl, generated by the enzyme myeloperoxidase under inflammatory conditions, and the unsaturated fatty acyl residues or the head group. In the first case the generated chlorohydrins are both proinflammatory and cytotoxic, thus having a significant impact on the structures of biomembranes. The latter case leads to chloramines, the properties of which are by far less well understood. Since HOCl is also widely used as a disinfecting and antibacterial agent in medicinal, industrial, and domestic applications, it may represent an additional source of danger in the case of abuse or mishandling. This review discusses the reaction behavior of in vivo generated HOCl and biomolecules like DNA, proteins, and carbohydrates but will focus on phospholipids. Not only the beneficial and pathological (toxic effects of chlorinated lipids but also the importance of these chlorinated species is discussed. Some selected cleavage products of (chlorinated phospholipids and plasmalogens such as lysophospholipids, (chlorinated free fatty acids and α-chloro fatty aldehydes, which are all well known to massively contribute to inflammatory diseases associated with oxidative stress, will be also discussed. Finally, common analytical methods to study these compounds will be reviewed with focus on mass spectrometric techniques.

  3. Impact of January 2005 solar proton events on chlorine species

    Directory of Open Access Journals (Sweden)

    A. Damiani

    2012-01-01

    Full Text Available Sudden changes in stratospheric chlorine species in the polar northern atmosphere, caused by the Solar Proton Events (SPEs of 17 and 20 January 2005, have been investigated and compared with version 4 of the Whole Atmosphere Community Climate Model (WACCM4. We used Aura Microwave Limb Sounder (MLS measurements to monitor the variability of ClO, HCl, HOCl and Michelson Interferometer for Passive Atmospheric Sounder (MIPAS on ENVISAT to retrieve ClONO2. SPE-induced chlorine activation has been identified. HCl decrease occurred at nearly all the investigated altitudes with the lowest values (of less than 0.25 ppbv on 21 January. HOCl was found to be the main active chlorine species under nighttime conditions (with increases of more than 0.2 ppbv whereas both HOCl and ClO enhancements (about 0.1 ppbv have been observed at the polar night terminator. Further, small ClO decreases (of less than 0.1 ppbv and ClONO2 enhancements (about 0.2 ppbv have been observed at higher latitudes (i.e., at nighttime roughly above 2 hPa.

    While WACCM4 reproduces most of the SPE-induced variability in the chlorine species fairly well, in some particular regions discrepancies between the modeled and measured temporal evolution of the abundances of chlorine species were found. HOCl changes are modelled very well with respect to both magnitude and geographic distribution. ClO decreases are reproduced at high latitudes, whereas ClO enhancements in the terminator region are underestimated and attributed to background variations. WACCM4 also reproduces the HCl depletion in the mesosphere but it does not show the observed decrease below about 2 hPa. Finally, WACCM4 simulations indicate that the observed ClONO2 increase is dominated by background variability, although SPE-induced production might contribute by 0.1 ppbv.

  4. Impact of January 2005 solar proton events on chlorine species

    Directory of Open Access Journals (Sweden)

    A. Damiani

    2012-05-01

    Full Text Available Sudden changes in stratospheric chlorine species in the polar northern atmosphere, caused by the Solar Proton Events (SPEs of 17 and 20 January 2005, have been investigated and compared with version 4 of the Whole Atmosphere Community Climate Model (WACCM4. We used Aura Microwave Limb Sounder (MLS measurements to monitor the variability of ClO, HCl, HOCl and Michelson Interferometer for Passive Atmospheric Sounder (MIPAS on ENVISAT to retrieve ClONO2. SPE-induced chlorine activation has been identified. HCl decrease occurred at nearly all the investigated altitudes (i.e., 10–0.5 hPa with the strongest decrease (of about 0.25 ppbv on 21 January. HOCl was found to be the main active chlorine species under nighttime conditions (with increases of more than 0.2 ppbv whereas both HOCl and ClO enhancements (about 0.1 ppbv have been observed at the polar night terminator. Further, small ClO decreases (of less than 0.1 ppbv and ClONO2 enhancements (about 0.2 ppbv have been observed at higher latitudes (i.e., at nighttime roughly above 2 hPa.

    While WACCM4 reproduces most of the SPE-induced variability in the chlorine species fairly well, in some particular regions discrepancies between the modeled and measured temporal evolution of the abundances of chlorine species were found. HOCl changes are modelled very well with respect to both magnitude and geographic distribution. ClO decreases are reproduced at high latitudes, whereas ClO enhancements in the terminator region are underestimated and attributed to background variations. WACCM4 also reproduces the HCl depletion in the mesosphere but it does not show the observed decrease below about 2 hPa. Finally, WACCM4 simulations indicate that the observed ClONO2 increase is dominated by background variability, although SPE-induced production might contribute by 0.1 ppbv.

  5. Roles of reactive chlorine species in trimethoprim degradation in the UV/chlorine process: Kinetics and transformation pathways.

    Science.gov (United States)

    Wu, Zihao; Fang, Jingyun; Xiang, Yingying; Shang, Chii; Li, Xuchun; Meng, Fangang; Yang, Xin

    2016-11-01

    The UV/chlorine process, which forms several reactive species including hydroxyl radicals (HO) and reactive chlorine species (RCS) to degrade contaminants, is being considered to be an advanced oxidation process. This study investigated the kinetics and mechanism of the degradation of trimethoprim (TMP) by the UV/chlorine process. The degradation of TMP was much faster by UV/chlorine compared to UV/H2O2. The degradation followed pseudo first-order kinetics, and the rate constant (k') increased linearly as the chlorine dosage increased from 20 μM to 200 μM and decreased as pH rose from 6.1 to 8.8. k' was not affected by chloride and bicarbonate but decreased by 50% in the presence of 1-mg/L NOM. The contribution of RCS, including Cl, Cl2(-) and ClO, to the degradation removal rate was much higher than that of HO and increased from 67% to 87% with increasing pH from 6.1 to 8.8 under the experimental condition. The increasing contribution of RCS to the degradation with increasing pH was attributable to the increase in the ClO concentration. Kinetic modeling and radical scavenging tests verified that ClO mainly attacked the trimethoxybenzyl moiety of TMP. RCS reacted with TMP much faster than HOCl/OCl(-) to form chlorinated products (i.e., m/z 325) and chlorinated disinfection byproducts such as chloroform, chloral hydrate, dichloroacetonitrile and trichloronitromethane. The hydroxylation and demethylation of m/z 325 driven by HO generated m/z 327 and m/z 341. Meanwhile, reactions of m/z 325 with HO and RCS/HOCl/OCl(-) generated dichlorinated and hydroxylated products (i.e., m/z 377). All the chlorinated products could be further depleted to produce products with less degree of halogenation in the UV/chlorine process, compared to dark chlorination. The acute toxicity to Vibrio fischeri by UV/chlorine was lower than chlorination at the same removal rate of TMP. This study demonstrated the importance of RCS, in particular, ClO, in the degradation of micropollutants

  6. Chlorine

    Science.gov (United States)

    ... but it is also used to make pesticides (insect killers), rubber, and solvents. Chlorine is used in ... the following signs and symptoms may develop: Blurred vision Burning pain, redness, and blisters on the skin ...

  7. Fatty acids and algal lipids as precursors of chlorination by-products

    Institute of Scientific and Technical Information of China (English)

    Yan Liang; Yuen Shan Lui; Huachang Hong

    2012-01-01

    Six common algal fatty acids (FAs) with different numbers of double bonds,lipophilic fractions and proteins extracted from the diatom Navicula pelliculosa and algal cells were chlorinated to evaluate their potential in generating disinfection by-products (DBPs).The result showed that the more double bonds in the FAs,the higher the amounts of chloroform and dichloroacetic acid (DCAA) produced,but such a pattern was not observed for trichloroacetic acid (TCAA).Based on the previously reported composition of fatty acids in algal lipids,the DBP generation potentials of algal lipids were calculated.These predicted values were much lower than those measured in the chlorinated algal lipophilic fraction,suggesting unknown lipophilic fraction(s) served as potent DBPs precursors.Another calculation attempted to predict DBP production in algal cells based on algal lipid and protein composition,given quantified measured DBP production per unit algal lipid and proteins.The analysis showed that the observed DBP production was similar to that predicted (< 35% difference),suggesting that algal biochemical compositions may serve as a bioindicator for preliminary estimation of chloroform,DCAA and TCAA formation upon chlorinating algae.

  8. Synergistic effect between UV and chlorine (UV/chlorine) on the degradation of carbamazepine: Influence factors and radical species.

    Science.gov (United States)

    Wang, Wen-Long; Wu, Qian-Yuan; Huang, Nan; Wang, Ting; Hu, Hong-Ying

    2016-07-01

    For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants. In this study, the synergistic treatment with UV irradiation and chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species (OH and Cl), and this process could be well depicted by pseudo first order kinetic. The degradation rate constants (kobs,CBZ) of CBZ increased linearly with increasing UV irradiance and chlorine dosage. The degradation of CBZ by UV/chlorine in acidic solutions was more efficient than that in basic solutions mainly due to the effect of pH on the dissociation of HOCl and OCl(-) and then on the quantum yields and radical species quenching of UV/chlorine. When pH was increased from 5.5 to 9.5, the rate constants of degradation of CBZ by OH decreased from 0.65 to 0.14 min(-1) and that by Cl decreased from 0.40 to 0.11 min(-1). The rate constant for the reaction between Cl and CBZ was 5.6 ± 1.6 × 10(10) M(-1) s(-1). Anions of HCO3(-) (1-50 mM) showed moderate inhibition of CBZ degradation by UV/chlorine, while Cl(-) did not. UV/chlorine could efficiently degrade CBZ in wastewater treatment plant effluent, although the degradation was inhibited by about 30% compared with that in ultrapure water with chlorine dosage of 0.14-0.56 mM. Nine main oxidation products of the CBZ degradation by UV/chlorine were identified using the HPLC-QToF MS/MS. Initial oxidation products arose from hydroxylation, carboxylation and hydrogen atom abstraction of CBZ by OH and Cl, and were then further oxidized to generate acylamino cleavage and decarboxylation products of acridine and acridione.

  9. Chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Talmage, Sylvia Smith [ORNL

    2009-01-01

    Following a brief description of the use of chlorine as a chemical warfare agent in World War I, this chapter summarizes physical and chemical data and recent clinical and controlled laboratory studies on the irritant and lethal effects of chlorine. The mechanism of toxicity for both irritation and lethal effects is described. The mathematical relationship between concentration and exposure duration for a set endpoint is given for both an irritancy response and mortality. This information can be used to assist in time-scaling for the set endpoint to other exposure durations. Risk assessment addresses the potential for greater effects in sensitive populations such as asthmatics. A concentration of 0.5 ppm for up to 8 hours is a no-adverse-effect concentration in most sensitive subjects; whereas, a concentration of 1.0 ppm induces some sensory irritation and transient changes in respiratory tract airflow parameters. Treatment and intervention of exposed individuals is dependent upon symptoms

  10. Multi-species biofilms defined from drinking water microorganisms provide increased protection against chlorine disinfection.

    Science.gov (United States)

    Schwering, Monika; Song, Joanna; Louie, Marie; Turner, Raymond J; Ceri, Howard

    2013-09-01

    A model biofilm, formed of multiple species from environmental drinking water, including opportunistic pathogens, was created to explore the tolerance of multi-species biofilms to chlorine levels typical of water-distribution systems. All species, when grown planktonically, were killed by concentrations of chlorine within the World Health Organization guidelines (0.2-5.0 mg l(-1)). Higher concentrations (1.6-40-fold) of chlorine were required to eradicate biofilm populations of these strains, ~70% of biofilms tested were not eradicated by 5.0 mg l(-1) chlorine. Pathogenic bacteria within the model multi-species biofilms had an even more substantial increase in chlorine tolerance; on average ~700-1100 mg l(-1) chlorine was required to eliminate pathogens from the biofilm, 50-300-fold higher than for biofilms comprising single species. Confocal laser scanning microscopy of biofilms showed distinct 3D structures and multiple cell morphologies and arrangements. Overall, this study showed a substantial increase in the chlorine tolerance of individual species with co-colonization in a multi-species biofilm that was far beyond that expected as a result of biofilm growth on its own.

  11. Sequential flow injection determination of chlorine species using a triiodide-selective electrode detector.

    Science.gov (United States)

    Saad, Bahruddin; Wai, Wan Tatt; Ali, Abdussalam Salhin M; Saleh, Muhammad Idiris

    2006-01-01

    A flow injection analysis (FIA) method for the determination of four residual chlorine species, namely combined available chlorine (CAC), free available chlorine (FAC), total available chlorine (TAC) and chlorite (ClO2-) was developed using a flow-through triiodide-selective electrode as a detector. An important strategy of speciation studies utilized the kinetic discrimination of reactions between the CAC and FAC with Fe2+, which was applied to the speciation of FAC, CAC and TAC. The speciation of available chlorine species and chlorite (an oxychlorine species) was achieved by using the same set-up, but using flow streams of different pH. The effects of the pH of the carrier stream, the flow rate and the sample volume were studied. The method exhibited linearity from 2.8 x 10(-6) to 2.8 x 10(-4) M active chlorine (expressed as OCl-) with a detection limit of 1.4 x 10(-6) M. The selectivity of the method was studied by examining the minimum pH for the oxidation of iodide by other oxidants, and also by assessing the potentiometric selectivity coefficients. The proposed method was successfully applied to the determination of chlorine species in tap water, and disinfecting formulations where good agreement occurred between the proposed and standard methods were found.

  12. Myeloperoxidase-catalyzed chlorination: the quest for the active species.

    Science.gov (United States)

    Ramos, Daniel R; García, M Victoria; Canle L, Moisés; Santaballa, J Arturo; Furtmüller, Paul G; Obinger, Christian

    2008-01-01

    Myeloperoxidase (MPO) is a dominating enzyme of circulating polymorphonuclear neutrophils that catalyzes the two-electron oxidation of chloride, thereby producing the strong halogenating agent hypochlorous acid (ClO(-)/HOCl). In absence of MPO the tripeptide Pro-Gly-Gly reacts with HOCl faster than the amino acid taurine (2-aminoethanesulfonic acid, Tau), while the MPO-mediated chlorination shows reverse order. A comparative study of the enzymatic oxidation of both substrates at pH 4.0-6.0, varying H2O2 concentration is presented. Initial and equilibrium rates studies have been carried on, reaction rates in the latter being slower due to the chemical equilibrium between MPO-I and MPO-II-HO2. A maximum of chlorination rate is observed for Pro-Gly-Gly and Tau when [H2O2] approximately 0.3-0.7 mM and pH approximately 4.5-5.0. Several mechanistic possibilities are considered, the proposed one implies that chlorination takes place via two pathways. One, for bulkier substrates, involves chlorination by free HOCl outside the heme cavity; ClO(-) is released from the active center, diffuses away the heme cavity, and undergoes protonation to HOCl. The other implies the existence of compound I-Cl(-) complex (MPO-I-Cl), capable of chlorinating smaller substrates in the heme pocket. Electronic structure calculations show the size of Pro-Gly-Gly comparable to the available gap in the substrate channel, this tripeptide being unable to reach the active site, and its chlorination is only possible by free HOCl outside the enzyme.

  13. The roles of reactive species in micropollutant degradation in the UV/free chlorine system.

    Science.gov (United States)

    Fang, Jingyun; Fu, Yun; Shang, Chii

    2014-01-01

    The UV/free chlorine process forms reactive species such as hydroxyl radicals (HO(•)), chlorine atoms (Cl(•)), Cl2(•-), and O(•-). The specific roles of these reactive species in aqueous micropollutant degradation in the UV/chlorine process under different conditions were investigated using a steady-state kinetic model. Benzoic acid (BA) was chosen as the model micropollutant. The steady-state kinetic model developed fitted the experimental data well. The results showed that HO(•) and Cl(•) contributed substantially to BA degradation, while the roles of the other reactive species such as Cl2(•-) and O(•-) were negligible. The overall degradation rate of BA decreased as the pH increased from 6 to 9. In particular, the relative contributions of HO(•) and Cl(•) to the degradation changed from 34.7% and 65.3% respectively at pH 6 to 37.9% and 62% respectively at pH 9 under the conditions evaluated. Their relative contributions also changed slightly with variations in chlorine dosage, BA concentration and chloride concentration. The scavenging effect of natural organic matter (NOM) on Cl(•) was relatively small compared to that on HO(•), while bicarbonate preferentially reduced the contribution of Cl(•). This study is the first to demonstrate the contributions of different reactive species to the micropollutant degradation in the UV/chlorine system under environmentally relevant conditions.

  14. Production of hydrogen by Clostridium species in the presence of chlorinated solvents.

    Science.gov (United States)

    Bowman, Kimberly S; Rainey, Fred A; Moe, William M

    2009-01-01

    Although anaerobic bioremediation of chlorinated organic contaminants in the environment often requires exogenous supply of hydrogen as an electron donor, little is known about the ability of hydrogen-producing bacteria to grow in the presence of chlorinated solvents. In this study, 18 Clostridium strains including nine uncharacterized isolates originating from chlorinated solvent contaminated groundwater were tested to determine their ability to fermentatively produce hydrogen in the presence of three common chlorinated aliphatic groundwater contaminants: 1,2-dichloroethane (DCA), 1,1,2-trichloroethane (TCA), and tetrachloroethene (PCE). All strains produced hydrogen in the presence of at least 7.4 mM DCA, 2.4 mM TCA, and 0.31 mM PCE. Some strains produced hydrogen in media containing concentrations as high as 29.7 mM DCA, 9.8 mM TCA, and 1.1 mM PCE. None of the strains biotransformed chlorinated solvents under the conditions tested. Results demonstrate that many Clostridium species are chlorinated solvent tolerant, producing hydrogen even in the presence of high concentrations of DCA, TCA, and PCE. These findings have important implications for bioremediation of contaminated soil and groundwater.

  15. Chlorine dioxide disinfection of single and dual species biofilms, detached biofilm and planktonic cells.

    Science.gov (United States)

    Behnke, Sabrina; Camper, Anne K

    2012-01-01

    Disinfection efficacy testing is usually done with planktonic cells or more recently, biofilms. While disinfectants are much less effective against biofilms compared to planktonic cells, questions regarding the disinfection tolerance of detached biofilm clusters remain largely unanswered. Burkholderia cepacia and Pseudomonas aeruginosa were grown in chemostats and biofilm tubing reactors, with the tubing reactor serving as a source of detached biofilm clusters. Chlorine dioxide susceptibility was assessed for B. cepacia and P. aeruginosa in these three sample types as monocultures and binary cultures. Similar doses of chlorine dioxide inactivated samples of chemostat and tubing reactor effluent and no statistically significant difference between the log(10) reductions was found. This contrasts with chlorine, shown previously to be generally less effective against detached biofilm particles. Biofilms were more tolerant and required chlorine dioxide doses ten times higher than chemostat and tubing reactor effluent samples. A second species was advantageous in all sample types and resulted in lower log(10) reductions when compared to the single species cultures, suggesting a beneficial interaction of the species.

  16. Lipid releasing characteristics of microalgae species through continuous ultrasonication.

    Science.gov (United States)

    Natarajan, Ramya; Ang, Wei Ming Russell; Chen, Xue; Voigtmann, Michael; Lau, Raymond

    2014-04-01

    In this study, the lipid releasing characteristics of several microalgae species through continuous ultrasonication was examined. Two marine microalgae species, Tetraselmis suecica and Nannochloropsis sp., and one freshwater species, Chlorella sp. were ultrasonicated directly after cultivation. The cell disruption efficiency and lipids releasing pattern from microalgae cells were measured under various ultrasonication conditions. It was found that cell disruption efficiency correlates well with ultrasonication energy consumption despite the ultrasonication conditions. Lipids in Chlorella sp. that has rigid cell walls were released to the aqueous phase after cell disruption. T. suecica and Nannochloropsis sp. that have flexible cell membranes tend to coil up and retain the membrane lipids after disruption. Continuous ultrasonication can be a potential method to release the lipids in rigid walled microalgae species without expensive dewatering steps.

  17. Short-chain chlorinated paraffins in terrestrial bird species inhabiting an e-waste recycling site in South China.

    Science.gov (United States)

    Luo, Xiao-Jun; Sun, Yu-Xin; Wu, Jiang-Ping; Chen, She-Jun; Mai, Bi-Xian

    2015-03-01

    Short-chain chlorinated paraffins (SCCPs) are under review by the Stockholm Convention on Persistent Organic Pollutants. Currently, limited data are available about SCCPs in terrestrial organisms. In the present study, SCCP concentration in the muscles of seven terrestrial bird species (n = 38) inhabiting an e-waste recycling area in South China was determined. This concentration varied from 620 to 17,000 ng/g lipid. Resident birds accumulated significantly higher SCCP concentrations than migratory birds (p < 0.01). Trophic magnification was observed for migratory bird species but not for resident, which was attributed to high heterogeneity of SCCP in e-waste area. Two different homologue group patterns were observed in avian samples. The first pattern was found in five bird species dominated by C10 and C11 congeners, while the second was found in the remains, which show rather equal abundance of homologue groups. This may be caused by two sources of SCCPs (local and e-waste) in the study area.

  18. Kinetic model for predicting the concentrations of active halogens species in chlorinated saline cooling waters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Haag, W.R.; Lietzke, M.H.

    1981-08-01

    A kinetic model has been developed for describing the speciation of chlorine-produced oxidants in seawater as a function of time. The model is applicable under a broad variety of conditions, including all pH range, salinities, temperatures, ammonia concentrations, organic amine concentrations, and chlorine doses likely to be encountered during power plant cooling water chlorination. However, the effects of sunlight are not considered. The model can also be applied to freshwater and recirculating water systems with cooling towers. The results of the model agree with expectation, however, complete verification is not feasible at the present because analytical methods for some of the predicted species are lacking.

  19. Pairing of cholesterol with oxidized phospholipid species in lipid bilayers

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Loubet, Bastien; Olzynska, Agnieszka

    2014-01-01

    We claim that (1) cholesterol protects bilayers from disruption caused by lipid oxidation by sequestering conical shaped oxidized lipid species such as 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PZPC) away from phospholipid, because cholesterol and the oxidized lipid have complementary...... shapes and (2) mixtures of cholesterol and oxidized lipids can self-assemble into bilayers much like lysolipid–cholesterol mixtures. The evidence for bilayer protection comes from molecular dynamics (MD) simulations and dynamic light scattering (DLS) measurements. Unimodal size distributions of extruded...... vesicles (LUVETs) made up of a mixture of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and PZPC containing high amounts of PZPC are only obtained when cholesterol is present in high concentrations. In simulations, bilayers containing high amounts of PZPC become porous, unless cholesterol is also present...

  20. Assessment of chlorine tolerance profile of Citrobacter species recovered from wastewater treatment plants in Eastern Cape, South Africa.

    Science.gov (United States)

    Owoseni, Mojisola; Okoh, Anthony

    2017-04-01

    This present study assessed the chlorine tolerance of some Citrobacter species recovered from secondary effluents from the clarifiers of two wastewater treatment plants in the Eastern Cape, South Africa. The bacterial survival, chlorine lethal dose and inactivation kinetics at lethal doses were examined. Inactivation of the test bacteria (n = 20) at the recommended dose of 0.5 mg/l for 30 min exposure showed a progressive reduction in bacterial population from 4 to 5 log reduction and residuals ranged between 0.12 and 0.46 mg/l. The bactericidal activity of chlorine increased at higher dosages with a substantial reduction in viability of the bacteria and complete inactivation of the bacterial population at a lethal dose of 0.75 and 1.0 mg/l in 30 min. For the inactivation kinetics, bactericidal activity of chlorine increased with time showing a 3.67-5.4 log reduction in 10 min, 4.0-5.6 log reduction in 20 min and above 6.3 log reductions to complete sterilization of bacterial population over 30 min for all the entire test Citrobacter isolates used in this study. Furthermore, there was a strong correlation (R (2) > 0.84) between bacteria inactivation and increase in contact time. This study appears to have provided support for laboratory evidence of bacterial tolerance to chlorine disinfection at current recommended dose (0.5 mg/l for 30 min), and chlorine concentration between 0.75 and 1.0 mg/l was found to have a better disinfecting capacity to check tolerance of Citrobacter species.

  1. Oxidation of diclofenac with chlorine dioxide in aquatic environments: influences of different nitrogenous species.

    Science.gov (United States)

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai; Ni, Tianjun

    2015-06-01

    The oxidation of diclofenac (DCF), a non-steroidal anti-inflammatory drug and emerging water pollutant, with chlorine dioxide was investigated under simulated water disinfection conditions. The reaction kinetics as functions of the initial concentrations of DCF, different nitrogenous species, and different pE values were experimentally determined. The results demonstrated that DCF reacted rapidly with ClO2, where more than 75 % of DCF (≤3.00 μM) was removed by 18.94 μM ClO2 within 60 s. All of the reactions followed pseudo first-order kinetics with respect to DCF, and the rate constant, k obs, exhibited a significant decrease from 4.21 × 10(-2) to 8.09 × 10(-3) s(-1), as the initial DCF concentration was increased from 1.00 to 5.00 μM. Furthermore, the degradation kinetics of DCF was clearly dependent on nitrogen-containing ion concentrations in the reaction solution. Ammonium and nitrite ions inhibited the DCF degradation by ClO2, whereas nitrate ion clearly initiated its promotion. In contrast, the inhibitory effect of NO2 (-) was more robust than that of NH4 (+). When the values of pE were gradually increased, the transformation of NH4 (+) to NO2 (-), and subsequently to NO3 (-), would occur, the rate constants were initially decreased, and then increased. When NH4 (+) and NO2 (-) coexisted, the inhibitory effect on the DCF degradation was less than the sum of the partial inhibitory effect. However, when NO2 (-) and NO3 (-) coexisted, the actual inhibition rate was greater than the theoretical estimate. These results indicated that the interaction of NH4 (+) and NO2 (-) was antagonistic, while the coexistence of NO2 (-) and NO3 (-) was observed to have a synergistic effect in aqueous environments.

  2. Fate of chlorinated fatty acids in migrating sockeye salmon and their transfer to arctic grayling

    DEFF Research Database (Denmark)

    Mu, Huiling; Ewald, G.; Nilsson, E.;

    2004-01-01

    organohalogen compounds in the salmon were halogenated fatty acids, predominantly chlorinated species that accounted for up to 35% of the extractable, organically bound chlorine (EOCl) in the fish tissues. The amount of chlorinated fatty acids in the salmon muscle decreased as a result of spawning migration....... The decrease was correlated with that of triacylglycerols in the salmon muscle, indicating the chlorinated fatty acids to be mobilized and metabolized to approximately the same extent as the other fatty acids. Chlorinated fatty acids were also transferred to the maturing roe in a manner similar...... to that of the unchlorinated fatty acids. Lipids of the Arctic grayling (Thymallus arcticus), a fish resident to the spawning lake of the salmon, contained higher concentrations of chlorinated fatty acids than grayling in a lake without migratory salmon. This may reflect a food-chain transfer of the chlorinated fatty acids...

  3. A DFT study of the interaction between large PAHs and atomic chlorine or hydrogen chloride molecule: Toward a modelling of the influence of chlorinated species on the trapping of water by soot

    Science.gov (United States)

    Garcia-Fernandez, C.; Radola, B.; Martin-Gondre, L.; Picaud, S.; Rayez, M. T.; Rayez, J. C.; Ouf, F. X.; Rubayo-Soneira, J.

    2017-02-01

    First-principle calculations have been performed to characterize the interaction of chlorinated species (HCl and Cl) with large polycyclic aromatic hydrocarbon (PAH) molecules and radicals. Whereas the characterization of the interaction process on the face of the PAH molecules requires taking into account long-range dispersion interactions in the calculations, trapping at the edge of PAH radicals involves stronger interactions that lead to the dissociation of the HCl molecule. Then, the first steps of water adsorption on the corresponding chlorinated species has been characterized, showing that chlorine may act as an efficient nucleation center for water molecules on such aromatic systems mimicking part of the carbonaceous surfaces that are likely present in soot. These results represent a first but necessary step for a better understanding of soot behavior in industrial or domestic fire situations.

  4. Reactive Oxygen Species, Lipid Peroxidation and Antioxidative Defense Mechanism

    Directory of Open Access Journals (Sweden)

    Hossam S. EL-BELTAGI

    2013-05-01

    Full Text Available Lipid peroxidation can be defined as the oxidative deterioration of lipids containing any number of carbon-carbon double bonds. Lipid peroxidation is a well-established mechanism of cellular injury in both plants and animals, and is used as an indicator of oxidative stress in cells and tissues. Lipid peroxides are unstable and decompose to form a complex series of compounds including reactive carbonyl compounds. The oxidation of linoleates and cholesterol is discussed in some detail. Analytical methods for studying lipid peroxidation were mentioned. Various kinds of antioxidants with different functions inhibit lipid peroxidation and the deleterious effects caused by the lipid peroxidation products.

  5. Associations of Pseudomonas species and forage grasses enhance degradation of chlorinated benzoic acids in soil

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, S. D.

    1998-12-01

    Using chlorinated benzoic acid (CBA) as a model compound, this study attempted to show that microorganisms and plants can be used as bioremediation agents to clean up contaminated soil sites in a cost effective and environmentally friendly manner. CBA was used because it is present in soils contaminated with polychlorinated biphenyls (PCBs), or chlorinated pesticides. Sixteen forage grasses were screened in combination with 12 bacterial inoculants for their ability to promote the degradation of CBA in soil. Five associations of plants and bacteria were found to degrade CBA to a greater extent than plants without bacterial inoculants. Bacterial inoculants were shown to stimulate CBA degradation by altering the microbial community present on the root surface and thereby increasing the ability of this community to degrade CBA.

  6. Observation of Chlorine and other RHS Species in the Marine Boundary Layer at Cape Verde Atmospheric Observatory

    Science.gov (United States)

    Pöhler, Denis; Tschritter, Jens; Lampel, Johannes; Frieß, Udo; Platt, Ulrich

    2014-05-01

    Reactive halogen species (RHS) have a significant influence on the marine atmosphere as they react with ozone, change the oxidation capacity and may form particles. However, their release processes, the emissions and concentrations of different RHS species are mostly uncertain. Only a few measurements exist and results are sometimes very different. Most studies focused on iodine and bromine species. Chlorine was mostly not investigated as it is typically more difficult to measure and it was expected that it has a smaller impact on the marine atmosphere and thus less significant. Recent model studies show that this assumption is probably not correct and more information of chlorine is needed to understand the processes in the marine atmosphere. We present results from measurements at the Cape Verde atmospheric research station (CVAO) during the HALOCAVE campaign in 2010 (June to October) using the LP-DOAS technique. Simultaneous measurements of a series of trace gases ranging from RHS like BrO, IO, ClO, OClO and other species like NO2, O3, CHOCHO, HCHO, SO2, HONO, NO3 have been performed along different measurement paths. In contrast to previous observations we could not observe IO above the detection limit of 0.5ppt. Also simultaneous CE-DOAS measurements could not observe IO above the detection limit of 1.0ppt. Profile retrievals of IO MAX-DOAS measurements show a concentration between 0.2 to 0.5ppt and thus in agreement with our LP-DOAS observations but not with previous findings. For BrO we found with the LP-DOAS concentrations up to 5ppt, a characteristic daily cycle with high variability from day to day indicating various metrological parameters to be significant for the bromine emission. ClO could not be observed above the relative high detection limit of approx. 25ppt. However, we found significant OClO concentrations in the night of up to 8ppt, which is most likely formed from ClO. This indicates significant chlorine concentrations in the marine atmosphere

  7. Partitioning and budget of inorganic and organic chlorine species observed by MIPAS-B and TELIS in the Arctic in March 2011

    Directory of Open Access Journals (Sweden)

    G. Wetzel

    2015-02-01

    Full Text Available The Arctic winter 2010/11 was characterized by a persisting vortex with extremely cold temperatures in the lower stratosphere above northern Scandinavia leading to a strong activation of chlorine compounds (ClOx like Cl, Cl2, ClO, ClOOCl, OClO, and HOCl which rapidly destroyed ozone when sunlight returned after winter solstice. MIPAS (Michelson Interferometer for Passive Atmospheric Sounding and TELIS (Terahertz and submillimeter Limb Sounder balloon measurements obtained in northern Sweden on 31 March 2011 inside the polar vortex have provided vertical profiles of inorganic and organic chlorine species as well as diurnal variations of ClO around sunrise over the whole altitude range in which chlorine is undergoing activation and deactivation. This flight was performed at the end of the winter during the last phase of ClOx deactivation. The complete inorganic and organic chlorine partitioning and budget in the stratosphere has been derived by combining MIPAS-B and TELIS simultaneously observed molecules. A total chlorine amount of 3.41 ± 0.30 ppbv is inferred from the measurements. This value is in line with previously carried out stratospheric observations confirming the slightly decreasing chlorine trend in the stratosphere. Observations are compared and discussed with the output of a multi-year simulation performed with the Chemistry Climate Model EMAC (ECHAM5/MESSy Atmospheric Chemistry. The simulated stratospheric total chlorine amount is in accordance with the MIPAS-B/TELIS observation taking into account the fact that some chlorine source gases and very short lived species are not included in the model.

  8. Depletion of ozone and reservoir species of chlorine and nitrogen oxide in the lower Antarctic polar vortex measured from aircraft

    Science.gov (United States)

    Jurkat, T.; Voigt, C.; Kaufmann, S.; Grooß, J.-U.; Ziereis, H.; Dörnbrack, A.; Hoor, P.; Bozem, H.; Engel, A.; Bönisch, H.; Keber, T.; Hüneke, T.; Pfeilsticker, K.; Zahn, A.; Walker, K. A.; Boone, C. D.; Bernath, P. F.; Schlager, H.

    2017-06-01

    Novel airborne in situ measurements of inorganic chlorine, nitrogen oxide species, and ozone were performed inside the lower Antarctic polar vortex and at its edge in September 2012. We focus on one flight during the Transport and Composition of the LMS/Earth System Model Validation (TACTS/ESMVal) campaign with the German research aircraft HALO (High-Altitude LOng range research aircraft), reaching latitudes of 65°S and potential temperatures up to 405 K. Using the early winter correlations of reactive trace gases with N2O from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), we find high depletion of chlorine reservoir gases up to ˜40% (0.8 ppbv) at 12 km to 14 km altitude in the vortex and 0.4 ppbv at the edge in subsided stratospheric air with mean ages up to 4.5 years. We observe denitrification of up to 4 ppbv, while ozone was depleted by 1.2 ppmv at potential temperatures as low as 380 K. The advanced instrumentation aboard HALO enables high-resolution measurements with implications for the oxidation capacity of the lowermost stratosphere.

  9. Removal of Methylene Blue Dye from Aqueous Solution Using a Newly Synthesized TiO2-SiO2 Photocatalyst in the Presence of Active Chlorine Species

    Science.gov (United States)

    Joseph, C. G.; Elilarasi, L.

    2017-06-01

    Industrialization and urbanization demand high amount of water consumption, which contributes to their polluted condition. Thus, there is a need to develop a sustainable wastewater remediation technique in order to provide sustainable use of clean water for future generations without ramifications to the economic sectors. The newly synthesized TiO2-SiO2 photocatalyst was used to remediate Methylene Blue contaminated aqueous solution in the presence of active chlorine species. The doping of SiO2 into TiO2 enhanced the removal rate of Methylene Blue dye from the solution by increasing the surface area, thermal stability and surface acidity of the TiO2. The active chlorine species further enhanced the removal rate of Methylene Blue dye from the solution by contributing more reactive species, chlorine radicals, which broke down the dye molecules. The experiments were conducted via Taguchi analysis. The findings show that combining TiO2, SiO2 and active chlorine species enhanced the removal percentage of Methylene Blue dye compared to using TiO2 alone by 70%. About 70% of 50ppm Methylene Blue was degraded by 1 g of TiO2-SiO2 in the presence of 0.3 ppm Ca(OCl)2 under 9 Watts solar irradiation within 3 hours. The enhanced dye removal method brings photocatalysis a step closer to sustainable wastewater remediation methods.

  10. Bipolar tetraether lipids derived from thermoacidophilic archaeon Sulfolobus acidocaldarius for membrane stabilization of chlorin e6 based liposomes for photodynamic therapy.

    Science.gov (United States)

    Mahmoud, Gihan; Jedelská, Jarmila; Strehlow, Boris; Bakowsky, Udo

    2015-09-01

    The initial burst release of water-soluble photosensitizers is one of the major problems encountered the development of controlled release formulations. In this study, the freely water soluble chlorin e6 (Ce6) was assembled with cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) to improve its loading efficiency in the liposomal bilayer. Tetraether lipids (TELs) derived from Sulfolobus acidocaldarius were added to DOTAP:Ce6 assembly in a concentration range of 2.5×10(-4)-1.6×10(-3)M to stabilize the membrane rigidity of the liposomes and to provide controlled release system. From the comparative spectroscopic experiments, it has been shown that the assembled DOTAP:Ce6 along with addition of TELs have improved the loading efficiency of Ce6 in TELs-liposomes and obviously modified the release profile of Ce6. The in vitro cell viability of Ce6 in mouse neuro-blastoma (Neuro-2a) and ovarian cell carcinoma (SK-OV-3) confirmed neglected dark cytotoxicity and presented potential photo-induced cytotoxicity with the effect was being more pronounced in Neuro 2a than in SK-OV-3. In-situ IV-injection of chick chorioallantoic membrane (CAM) showed hemorrhage and necrosis 30 min post irradiation at 1.8 mol% TELs (19.9J/cm(2)). Higher TELs of 2.2 and 3.7 mol% in particular demonstrated localized vascular destruction within the irradiated area. Our results suggest that TELs favored slower release rates of Ce6. This, in turn, tetraether lipids can be considered as a versatile class of lipids for photodynamic modality for destruction of cancer cells and tumor vasculature while sparing the quiescent ones.

  11. Low-Chlorinated Non-Dioxin-like Polychlorinated Biphenyls Present in Blood and Breast Milk Induce Higher Levels of Reactive Oxygen Species in Neutrophil Granulocytes than High-Chlorinated Congeners.

    Science.gov (United States)

    Berntsen, Hanne Friis; Fonnum, Frode; Walaas, Sven Ivar; Bogen, Inger Lise

    2016-12-01

    Despite their ban several decades ago, polychlorinated biphenyls (PCBs) still pose a health threat to human beings due to their persistent and accumulative nature and continued presence in the environment. Non-dioxin-like (NDL)-PCBs have earlier been found to have effects on the immune system, including human neutrophil granulocytes. The aim of this study was to investigate the differences between ortho-chlorinated NDL-PCBs with a low or high degree of chlorination in their capability to induce the production of reactive oxygen species (ROS) in human neutrophil granulocytes in vitro. We used some of the congeners occurring at the highest levels in blood, breast milk and food: PCB 52 representing the low-chlorinated congeners and PCB 180 the high-chlorinated congeners. In addition, the extensively studied PCB 153 was included as a reference compound. ROS production was assessed with the luminol-amplified chemiluminescence and DCF fluorescence assays. The involvement of intracellular signalling mechanisms was investigated using different pharmacological substances. At high concentrations (10-20 μM), PCB 52 induced more ROS than PCB 153 and PCB 180. The role of extracellular signal-regulated kinase (ERK) 1/2 and/or ERK 5 signalling in PCB-induced ROS production was implicated through the reduction in ROS in the presence of the specific inhibitor U0126, whereas reduced ROS production after the use of SB203580 and SP600125 indicated the involvement of the p38 mitogen-activated protein kinase (MAPK) and c-Jun amino-terminal kinase (JNK) pathways, respectively. In addition, the calcineurin inhibitor FK-506, the intracellular calcium chelator BAPTA-AM and the antioxidant vitamin E reduced the levels of ROS. The intracellular signalling mechanisms involved in ROS production in human neutrophil granulocytes appeared to be similar for PCB 52, PCB 153 and PCB 180. Based on the results from the present and previous studies, we conclude that for abundant ortho-chlorinated PCBs

  12. Reactions of aqueous chlorine and chlorine dioxide with model food compounds.

    Science.gov (United States)

    Fukayama, M Y; Tan, H; Wheeler, W B; Wei, C I

    1986-01-01

    Chlorine and chlorine dioxide (ClO2), common disinfecting and bleaching chemicals used in the food industry, are potent oxidizing and chlorinating agents. Unfortunately, little is known about the nature of the reactions of chlorine with organic food constituents. This presentation reviews published information concerning the reactions of chlorine gas (Cl2[g]), aqueous chlorine, and ClO2 with model food compounds, the fate of chlorine during the chlorination of specific food products, and the potential toxicity of the reaction products. Fatty acids and their methyl esters react with chlorine with the degree of incorporation corresponding to their degree of unsaturation. Aqueous chlorine oxidizes and chlorinates lipids and amino acids much more readily than ClO2. Several amino acids are highly susceptible to oxidation and chlorination by chlorine compounds. Reactions of chlorine and ClO2 with several food products, including flour and shrimp, have also been characterized. In one model system, 99% of Cl2(g) either reacted with components of flour or was consumed by oxidation/chlorination reactions. The lipids extracted from the chlorinated flour contained significant amounts of chlorine. Exposure of shrimp to hypochlorous acid (HOCl) solution resulted in significant incorporation of chlorine into the edible portion. Although significant quantities of chlorine can be incorporated into specific model compounds and food products, the health risks associated with exposure to chlorinated organic products are unknown. Preliminary studies using the Ames Salmonella/microsome mutagenicity assay indicate that the reaction products from mixtures of aqueous chlorine and various lipids or tryptophan are nonmutagenic. Nevertheless, additional studies are warranted, so that the toxicological significance of these reaction products can be understood more fully. PMID:3545804

  13. Chlorine dioxide as a treatment for ballast water to control invasive species: shipboard testing.

    Science.gov (United States)

    Maranda, Lucie; Cox, Annie M; Campbell, Robert G; Smith, David C

    2013-10-15

    The efficacy of chlorine dioxide (ClO2) in eliminating organisms present in estuarine ballast water of a containership was determined under actual operating conditions by comparing the survival of planktonic communities present in waters of treated and control ballast tanks. Sampling was via ballast-tank hatches. The treatment (5 mg L(-1)ClO2 without pre-filtration) delivered by a prototype ClO2-generating system was generally effective against planktonic assemblages, although bacterial communities rebounded after a few days. Regardless of temperature, ClO2 was very effective against phytoplankton; the effect was immediate, without resurgence. Some zooplankters in the ≥ 50-μm fraction may survive the biocide, especially those able to find refuge within a protective coating (e.g., cysts, resting eggs, and shells) or in sediment. In order to boost efficacy, a pre-filtration step is recommended (now installed as standard equipment) to lower the intake of the ≥ 50-μm fraction and lessen the challenge posed by this size class.

  14. Reaction products of chlorine dioxide.

    Science.gov (United States)

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxide treatment of organic materials are oxidized species, some of which also contain chlorine. The relative amounts of species types may depend on the amount of chlorine dioxide residual maintained and the concentration and nature of the organic material present in the source water. The trend toward lower concentrations of chlorinated by-products with increasing ClO2 concentration, which was observed with phenols, has not been observed with natural humic materials as measured by the organic halogen parameter. Organic halogen concentrations have been shown to increase with increasing chlorine dioxide dose, but are much lower than those observed when chlorine is applied. Aldehydes have been detected as apparent by-products of chlorine dioxide oxidation reactions in a surface water that is a drinking water source. Some other nonchlorinated products of chlorine dioxide treatment may be quinones and epoxides. The extent of formation of these moieties within the macromolecular humic structure is also still unknown. PMID:7151750

  15. Accurate Quantification of Lipid Species by Electrospray Ionization Mass Spectrometry — Meets a Key Challenge in Lipidomics

    Directory of Open Access Journals (Sweden)

    Kui Yang

    2011-11-01

    Full Text Available Electrospray ionization mass spectrometry (ESI-MS has become one of the most popular and powerful technologies to identify and quantify individual lipid species in lipidomics. Meanwhile, quantitative analysis of lipid species by ESI-MS has also become a major obstacle to meet the challenges of lipidomics. Herein, we discuss the principles, advantages, and possible limitations of different mass spectrometry-based methodologies for lipid quantification, as well as a few practical issues important for accurate quantification of individual lipid species. Accordingly, accurate quantification of individual lipid species, one of the key challenges in lipidomics, can be practically met.

  16. Comparison of Nitrogen Depletion and Repletion on Lipid Production in Yeast and Fungal Species

    Directory of Open Access Journals (Sweden)

    Shihui Yang

    2016-08-01

    Full Text Available Although it is well known that low nitrogen stimulates lipid accumulation, especially for algae and some oleaginous yeast, few studies have been conducted in fungal species, especially on the impact of different nitrogen deficiency strategies. In this study, we use two promising consolidated bioprocessing (CBP candidates to examine the impact of two nitrogen deficiency strategies on lipid production, which are the extensively investigated oleaginous yeast Yarrowia lipolytica, and the commercial cellulase producer Trichoderma reesei. We first utilized bioinformatics approaches to reconstruct the fatty acid metabolic pathway and demonstrated the presence of a triacylglycerol (TAG biosynthesis pathway in Trichoderma reesei. We then examined the lipid production of Trichoderma reesei and Y. lipomyces in different media using two nitrogen deficiency strategies of nitrogen natural repletion and nitrogen depletion through centrifugation. Our results demonstrated that nitrogen depletion was better than nitrogen repletion with about 30% lipid increase for Trichoderma reesei and Y. lipomyces, and could be an option to improve lipid production in both oleaginous yeast and filamentous fungal species. The resulting distinctive lipid composition profiles indicated that the impacts of nitrogen depletion on yeast were different from those for fungal species. Under three types of C/N ratio conditions, C16 and C18 fatty acids were the predominant forms of lipids for both Trichoderma reesei and Y. lipolytica. While the overall fatty acid methyl ester (FAME profiles of Trichoderma reesei were similar, the overall FAME profiles of Y. lipolytica observed a shift. The fatty acid metabolic pathway reconstructed in this work supports previous reports of lipid production in T. reesei, and provides a pathway for future omics studies and metabolic engineering efforts. Further investigation to identify the genetic targets responsible for the effect of nitrogen depletion on

  17. Minor lipid components of some Acacia species: potential dietary health benefits of the unexploited seeds

    Directory of Open Access Journals (Sweden)

    Nasri Nizar

    2012-05-01

    Full Text Available Abstract Background Oilseed samples from four Acacia species ( A. cyclops, A. ligulata, A. salicina and A. cyanophylla were analyzed in order to evaluate the potential nutritional value of their unexploited seeds. Methods Samples were collected from different Tunisian geographic locations. Seed oils were extracted and carotenoids, tocopherols and sterols were analyzed using chromatographic methods. Results The studied Acacia seeds seem to be quite rich in lipids (from 6% to 12%. All Acacia species contain mainly the xanthophylls zeaxanthin and lutein compounds: from ca. 38 mg.kg-1 of total lipids (A. cyclops to ca. 113 mg.kg-1 of total lipids (A. cyanophylla. Total tocopherols varied from ca. 221 mg.kg-1 of total lipids (A. cyclops to ca. 808 mg.kg-1 of total lipids (A. ligulata. Sterols are highly present and their contents ranged between ca. 7 g. kg-1 of total lipids (A. salicina and 11 g. kg-1 of total lipids (A. cyclops. Conclusion This study highlights that these unexploited seeds might have a potential nutritional value and encourages researchers to more explore and find developments for these plants for healthy purposes.

  18. Effect of heavy metals on plasma membrane lipids and antioxidant enzymes of Zygophyllum species

    Directory of Open Access Journals (Sweden)

    Amal Ahmed Morsy

    2012-01-01

    Full Text Available Background: Heavy metals are major environmental pollutant when they present in high concentration in soil and have toxic effects on growth and development of plants. Industrial activities result in heavy metal pollution of large areas of land, which greatly affects natural vegetation. Understanding the mechanism of how plants combat heavy metals adverse effects is hence of great importance. Materials and Methods: Two different localities were chosen; one locality was in the vicinity of gypsum factory and the other one was 25 km away from the factory. Two Zygophyllum species (Z. album and Z. coccineum were naturally grown in the studied areas. The effects of soil heavy metal stress on shoot heavy metal concentrations, lipid peroxidation, antioxidant enzyme activities and the root plasma membrane (PM lipid composition were analyzed. Results: Heavy metal concentrations and Lipid peroxidation increased in the shoot of both species grown in the polluted area. The activities of ascorbate oxidase (ASO, guaiacal peroxidase (GPX, ascorbate peroxidase (APX and superoxide dismutase (SOD were increased whereas these of catalase (CAT were decreased in both species under the polluted conditions. PM total lipids, phospholipids, glycolipids and sterols were decreased in Z. album and Z. coccineum as a result of the polluted soil. Heavy metal stress increased phosphatidylethanolamine (PE and decreased phosphatidylinositol (PI and phophatidylglycerol (PG, with no significant change in phosphatidylcholine (PC in the root PM of both species. Phosphatidylserine (PS decreased in the PM of Z. album whereas it increased in the PM of Z. coccineum under the pollution conditions. Heavy metal stress changed the composition and concentration of fatty acids of the root PM, resulting in increased sat/unsat ratio of both species. Conclusion: the results suggest that efficient antioxidant machinery and favorable PM lipid homeostasis are important to enable Zygophyllum species

  19. Evaluation of disinfection by-product formation potential (DBPFP) during chlorination of two algae species--Blue-green Microcystis aeruginosa and diatom Cyclotella meneghiniana.

    Science.gov (United States)

    Liao, Xiaobin; Liu, Jinjin; Yang, Mingli; Ma, Hongfang; Yuan, Baoling; Huang, Ching-Hua

    2015-11-01

    Microcystis aeruginosa (blue-green alga) commonly blooms in summer and Cyclotella meneghiniana (diatom) outbreaks in fall in the reservoirs that serve as drinking water sources in Southeast China. Herein, an evaluation of disinfection by-product formation potential (DBPFP) from them during chlorination should be conducted. Five DBPs including trichloromethane (TCM), trichloronitromethane (TCNM), dichloroacetonitrile (DCAN), 1,1-dichloropropanone (1,1-DCP) and 1,1,1-trichloropropanone (1,1,1-TCP) were monitored. The formation potential of TCM and TCNM was enhanced with the increase of reaction time and chlorine dosage, whereas that of DCAN, 1,1-DCP and 1,1,1-TCP increased first and then fell with continuing reaction time. M. aeruginosa showed higher DBPFP than C. meneghiniana, the yield of DBPs varied with components of algal cells. The DBPFP order from components of M. aeruginosa was cell suspension (CS) ≈ intracellular organic matter (IOM) > extracellular organic matter (EOM) > cell debris (CD), which indicated that IOM was the main DBP precursors for M. aeruginosa. The yields of DBPs from components of C. meneghiniana were in the order of CS>IOM≈ CD ≈ EOM, suggesting that three components made similar contributions to the total DBP formation. The amount of IOM with higher DBPFP leaked from both algae species increased with the chlorine dosage, indicating that chlorine dosage should be considered carefully in the treatment of eutrophic water for less destroying of the cell integrity. Though fluorescence substances contained in both algae species varied significantly, the soluble microbial products (SMPs) and aromatic protein-like substances were the main cellular components that contributed to DBP formation for both algae.

  20. Comparing the chlorine disinfection of detached biofilm clusters with those of sessile biofilms and planktonic cells in single- and dual-species cultures.

    Science.gov (United States)

    Behnke, Sabrina; Parker, Albert E; Woodall, Dawn; Camper, Anne K

    2011-10-01

    Although the detachment of cells from biofilms is of fundamental importance to the dissemination of organisms in both public health and clinical settings, the disinfection efficacies of commonly used biocides on detached biofilm particles have not been investigated. Therefore, the question arises whether cells in detached aggregates can be killed with disinfectant concentrations sufficient to inactivate planktonic cells. Burkholderia cepacia and Pseudomonas aeruginosa were grown in standardized laboratory reactors as single species and in coculture. Cluster size distributions in chemostats and biofilm reactor effluent were measured. Chlorine susceptibility was assessed for planktonic cultures, attached biofilm, and particles and cells detached from the biofilm. Disinfection tolerance generally increased with a higher percentage of larger cell clusters in the chemostat and detached biofilm. Samples with a lower percentage of large clusters were more easily disinfected. Thus, disinfection tolerance depended on the cluster size distribution rather than sample type for chemostat and detached biofilm. Intact biofilms were more tolerant to chlorine independent of species. Homogenization of samples led to significantly increased susceptibility in all biofilm samples as well as detached clusters for single-species B. cepacia, B. cepacia in coculture, and P. aeruginosa in coculture. The disinfection efficacy was also dependent on species composition; coculture was advantageous to the survival of both species when grown as a biofilm or as clusters detached from biofilm but, surprisingly, resulted in a lower disinfection tolerance when they were grown as a mixed planktonic culture.

  1. Reactions of aqueous chlorine and chlorine dioxide with model food compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fukayama, M.Y.; Tan, H.; Wheeler, W.B.; Wei, C.

    1986-11-01

    This presentation reviews published information concerning the reactions of chlorine gas (CL/sub 2/(g)), aqueous chlorine, and ClO/sub 2/ with model food compounds, the fate of chlorine during the chlorination of specific food products, and the potential toxicity of the reaction products. Fatty acids and their methyl esters react with chlorine with the degree of incorporation corresponding to their degree of unsaturation. Aqueous chlorine oxidizes and chlorinates lipids and amino acids much more readily than ClO/sub 2/. Several amino acids are highly susceptible to oxidation and chlorination by chlorine compounds. Reactions of chlorine and ClO/sub 2/ with several food products, including flour and shrimp, have also been characterized. Although significant quantities of chlorine can be incorporated into specific model compounds and food products, the health risks associated with exposure to chlorinated organic products are unknown. Preliminary studies using the Ames Salmonella/microsome mutagenicity assay indicate that the reaction products from mixtures of aqueous chlorine and various lipids or tryptophan are nonmutagenic. Nevertheless, additional studies are warranted, so that the toxicological significance of these reaction products can be understood more fully.

  2. Lipid Status of the Two High Latitude Fish Species, Leptoclinus maculatus and Lumpenus fabricii

    Directory of Open Access Journals (Sweden)

    Nina N. Nemova

    2013-03-01

    Full Text Available A comparative study of the lipid status (i.e., the total lipid and phospholipid concentrations and the percentage of fatty acids of the total lipids of adult specimens of daubed shanny (Leptoclinus maculatus from Svalbard waters (Isfjord and slender eel blenny (Lumpenus fabricii from the White Sea (Onega Bay and Tersky shore was performed to study the metabolism and functions of lipids of these fishes in ontogeny and under various ecological conditions. Slender eel blenny from both areas of the White Sea were distinguished by a high level of sphingomyelin compared with the daubed shanny from Svalbard, and the amount of total phospholipids was higher in slender eel blenny from Onega Bay than in slender eel blenny from the Tersky shore. The extent of saturation and the signature of polyenic fatty acids varied according to the specific species of the Stichaeidae family under study. These results demonstrate the differences in the trophoecological and hydrobiological conditions of habitations of these species and highlighted the importance of considering certain trends in the lipid profiles of these fishes as specific features of the organization of the ecological and biochemical mechanisms of adaptation.

  3. MERCURY REACTIONS IN THE PRESENCE OF CHLORINE SPECIES: HOMOGENOUS GAS PHASE AND HETEROGENOUS GAS-SOLID PHASE

    Science.gov (United States)

    The kinetics of mercury chlorination (with HC1) were studied using a flow reactor system with an on-line Hg analyzer and spciation sampling using a set of impingers. Kinetic parameters, such as reaction order (a), activation energy (Eu) and the overall rate constant (k') were es...

  4. A Compartmental Comparison of Major Lipid Species in a Coral-Symbiodinium Endosymbiosis: Evidence that the Coral Host Regulates Lipogenesis of Its Cytosolic Lipid Bodies.

    Directory of Open Access Journals (Sweden)

    Hung-Kai Chen

    Full Text Available The lipid body (LB formation in the host coral gastrodermal cell cytoplasm is a hallmark of the coral-Symbiodinium endosymbiosis, and such lipid-based entities are not found in endosymbiont-free cnidarian cells. Therefore, the elucidation of lipogenesis regulation in LBs and how it is related to the lipid metabolism of the host and endosymbiont could provide direct insight to understand the symbiosis mechanism. Herein, the lipid composition of host cells of the stony coral Euphyllia glabrescens, as well as that of their cytoplasmic LBs and in hospite Symbiodinium populations, was examined by high performance liquid chromatography (HPLC and gas chromatography/mass spectrometry (GC/MS, and six major lipid species were identified: wax esters, sterol esters, triacylglycerols, cholesterols, free fatty acids, and phospholipids. Their concentrations differed significantly between host coral cells, LBs, and Symbiodinium, suggesting compartmental regulation. WE were only present in the host coral and were particularly highly concentrated in LBs. Amongst the four species of WE, the monoene R = C18:1/R = C16 was found to be LB-specific and was not present in the host gastrodermal cell cytoplasm. Furthermore, the acyl pool profiles of the individual LB lipid species were more similar, but not equal to, those of the host gastrodermal cells in which they were located, indicating partially autonomous lipid metabolism in these LBs. Nevertheless, given the overall similarity in the host gastrodermal cell and LB lipid profiles, these data suggest that a significant portion of the LB lipids may be of host coral origin. Finally, lipid profiles of the in hospite Symbiodinium populations were significantly distinct from those of the cultured Symbiodinium, potentially suggesting a host regulation effect that may be fundamental to lipid metabolism in endosymbiotic associations involving clade C Symbiodinium.

  5. Lipid content and composition of oocytes from five coral species: potential implications for future cryopreservation efforts.

    Directory of Open Access Journals (Sweden)

    Chiahsin Lin

    Full Text Available Given the previously documented importance of lipid concentration and composition in the successful cryopreservation of gorgonian corals, these parameters were assessed in oocytes of five species of scleractinian coral; Platygyra daedalea, Echinopora gemmacea, Echinophyllia aspera, Oxypora lacera and Astreopora expansa. Wax esters, phosphatidylethanolamine, phosphatidylcholine, and fatty acids were all measured at detectable levels, and the latter were produced at significantly elevated quantities in E. gemmacea, E. aspera, and O. lacera. On the other hand, phosphatidylethanolamine, phosphatidylcholine, and wax ester were found at significantly higher concentrations in A. expansa oocytes. Triacylglycerol was not present in any species. Interestingly, the total lipid content of oocytes from all five scleractinians was significantly lower than that of oocytes of two gorgonian species, Junceella juncea and Junceella fragilis. As higher total lipid concentrations may be correlated with greater degrees of cellular membrane fluidity at lower temperatures, it stands to reason that gorgonian coral oocytes may be more likely to survive the cryopreservation process than oocytes of scleractinian corals.

  6. Profiling of lipid species by normal-phase liquid chromatography, nanoelectrospray ionization, and ion trap-orbitrap mass spectrometry

    DEFF Research Database (Denmark)

    Sokol, Elena; Almeida, Reinaldo; Hannibal-Bach, Hans Kristian

    2013-01-01

    chromatography-Fourier transform mass spectrometry (LC-FTMS) and LC-ITMS(2) (ion trap tandem mass spectrometry) for profiling and structural analysis of lipid species. The workflow uses a normal-phase LC system for efficient separation of apolar and polar lipid species combined with sensitive and specific...... analysis powered by a chip-based nanoelectrospray ion source and a hybrid ion trap-orbitrap mass spectrometer. The workflow was executed using a primary LC-FTMS survey routine for identification and profiling of lipid species based on high-mass accuracy and retention time followed by a targeted LC-ITMS(2......Detailed analysis of lipid species can be challenging due to their structural diversity and wide concentration range in cells, tissues, and biofluids. To address these analytical challenges, we devised a reproducible, sensitive, and integrated lipidomics workflow based on normal-phase liquid...

  7. First isolation of an antifungal lipid transfer peptide from seeds of a Brassica species.

    Science.gov (United States)

    Lin, Peng; Xia, Lixin; Ng, T B

    2007-08-01

    An antifungal peptide with a molecular mass of 9412 and an N-terminal sequence exhibiting notable homology to those of lipid transfer proteins was isolated from seeds of the vegetable Brassica campestris. The purification protocol entailed ion exchange chromatography on Q-Sepharose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography by fast protein liquid chromatography (FPLC) on Mono S, and gel filtration by FPLC on a Superdex peptide column. The antifungal peptide was adsorbed on Affi-gel blue gel and Mono S. It inhibited mycelial growth in Fusarium oxysporum and Mycosphaerella arachidicola with an IC(50) value of 8.3 microM and 4.5 microM, respectively. It exhibited dose-dependent binding to lyso-alpha-lauroyl phosphatidylcholine. The present findings constitute the first report on a non-specific lipid transfer protein from the seeds of a Brassica species.

  8. Aminoguanidine inhibits reactive oxygen species formation, lipid peroxidation, and oxidant-induced apoptosis.

    Science.gov (United States)

    Giardino, I; Fard, A K; Hatchell, D L; Brownlee, M

    1998-07-01

    Aminoguanidine (AG) treatment, like nerve growth factor (NGF) treatment, prevents diabetes-induced apoptosis of retinal Müller cells in the rat eye, but the mechanism involved is unknown. In this study, the effects of preincubation with AG on oxidant-induced apoptosis, oxidant-induced intracellular reactive oxygen species (ROS) production, and lipid peroxidation were determined in rat retinal Müller cells and compared with the effects of NGF, a protein that protects neuronal cells from oxidative stress. The effect of AG on rabbit vitreous lipid peroxide levels was also determined. After exposure to increasing concentrations of H2O2, there was a corresponding increase in the percentage of apoptotic Müller cells. Preincubation with AG for 48 h completely inhibited oxidant-induced apoptosis in response to 10 micromol/l H2O2 (+AG 0 vs. 10 micromol/l, NS), and reduced the percentage of apoptotic cells in response to 50 micromol/l H2O2 by 50% (+AG vs. -AG, P NGF. Both AG and NGF preincubation prevented the twofold increase in oxidant-induced lipid peroxides. The fivefold increase in oxidant-induced ROS production was decreased 100% by NGF, but only 61% by AG preincubation. The twofold increase in vitreous lipid peroxide level in diabetic rabbits was completely prevented by AG treatment. AG reduced H2O2-induced benzoate hydroxylation in a dose-dependent manner. Intracellular glutathione content was unchanged. These data demonstrate that AG can act as an antioxidant in vivo, quenching hydroxyl radicals and lipid peroxidation in cells and tissues and preventing oxidant-induced apoptosis.

  9. Reactive oxygen species, lipid peroxidation and enzymatic defence systems in human spermatozoa.

    Science.gov (United States)

    Griveau, J F; Dumont, E; Renard, P; Callegari, J P; Le Lannou, D

    1995-01-01

    The reactive oxygen species, hydrogen peroxide (H2O2) and superoxide anion (O2o-), were generated with a xanthine-xanthine oxidase system and their effect on human sperm function was studied. The action of reactive oxygen species on selected human spermatozoa resulted in a decreased capacity for ionophore-induced acrosome reaction, a decrease in sperm motility, an increase in the concentration of lipid hydroperoxides and a loss of membrane polyunsaturated fatty acids. H2O2 was the key intermediate of the deleterious effects exerted by the xanthine and xanthine oxidase. Among these parameters, the acrosome reaction appeared most susceptible to the reactive oxygen species generated by the xanthine-xanthine oxidase system, and was decreased without sperm motility being affected. Treatment with H2O2 was shown to inactivate several enzymatic activities involved in the antioxidant defence of spermatozoa: glutathione peroxidase, superoxide dismutase and glucose-6-phosphate dehydrogenase. H2O2 and O2o- were shown to be involved in the lipid alterations triggered by the xanthine-xanthine oxidase system. Singlet oxygen is proposed to intervene in the lipoperoxidation process. The inefficacy of mannitol in protecting spermatozoa suggests that hydroxyl radicals were not produced in the extracellular medium.

  10. Characterization of lipid model membranes designed for studying impact of ceramide species on drug diffusion and penetration.

    Science.gov (United States)

    Ochalek, M; Heissler, S; Wohlrab, J; Neubert, R H H

    2012-05-01

    The stratum corneum (SC) intercellular lipid matrix plays a crucial role in the skin barrier function. In the present study, lipid model membranes mimicking its phase behavior were prepared and characterized using different analytical techniques (i.a. SAXD, HPTLC, ESEM, confocal Raman imaging, ATR-FTIR spectroscopy) in order to obtain well-standardized model membranes for diffusion and penetration studies. The lipid model membranes should be used in the future for studying the impact of each ceramide species on the diffusion and penetration of drugs. The SAXD study confirmed that the lipids within artificial lipid systems are arranged similarly to the lipids in the human SC. The polarization microscopic and ESEM images showed the homogenous deposition of lipids on the polycarbonate filter. Both the HPTLC and confocal Raman imaging studies proved the homogenous distribution of individual lipid classes within the lipid model membranes. First in vitro diffusion experiments (performed using an ATR-FTIR diffusion cell) of the hydrophilic compound, urea, revealed that the lipid model membrane represents even stronger diffusion barrier than the human SC. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Characterisation Of Polysacharides And Lipids From Selected Green Algae Species By FTIR-ATR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Bartošová Alica

    2015-06-01

    Full Text Available Fourier transform infrared (FTIR spectroscopy was used in this study to identify and determine spectral features of Chromochloris zofingiensis (Dönz Fucíková et L.A. Lewis (SAG 211-14, Gottingen, Germany, Acutodesmus obliguus (Turpin Hegewald (SAG 276-1, Gottingen, Germany and Chlorella sorokiniana (K. Brandt Pröschold et Darienko (SAG 211-40c, Gottingen, Germany. Polysaccharides and lipids from these three algae species were determined using Fourier Transformed Infrared Spectroscopy (FTIR with ATR accessory with diamante crystal in spectral range from 400 – 4000 cm−1 and resolution 4.

  12. Strategies to enhance the production of photosynthetic pigments and lipids in chlorophycae species

    Directory of Open Access Journals (Sweden)

    Juan Roberto Benavente-Valdés

    2016-06-01

    Full Text Available Microalgae are a major natural source for a vast array of valuable compounds as lipids, proteins, carbohydrates, pigments among others. Despite many applications, only a few species of microalgae are cultured commercially because of poorly developed of cultivation process. Nowadays some strategies of culture have been used for enhancing biomass and value compounds yield. The most strategies applied to microalgae are classified into two groups: nutrimental and physical. The nutrimental are considered as change in media composition as nitrogen and phosphorous limitation and changes in carbon source, while physical are described as manipulation in operational conditions and external factors such as application of high-light intensities, medium salinity and electromagnetic fields. The exposition to electromagnetic field is a promising technique that can improve the pigments and biomass yield in microalgae culture. Therefore, is important to describe the advantages and applications of the overall process. The aim of this review was to describe the main culture strategies used to improve the photosynthetic and lipids content in chlorophyceae species.

  13. Analytical strategy for the determination of various arsenic species in landfill leachate containing high concentrations of chlorine and organic carbon by HPLC-ICPMS

    Science.gov (United States)

    Bae, J.; An, J.; Kim, J.; Jung, H.; Kim, K.; Yoon, C.; Yoon, H.

    2012-12-01

    As a variety of wastes containing arsenic are disposed of in landfills, such facilities can play a prominent role in disseminating arsenic sources to the environment. Since it is widely recognized that arsenic toxicity is highly dependent on its species, accurate determination of various arsenic species should be considered as one of the essential goals to properly account for the potential health risk of arsenic in human and the environment. The inductively coupled plasma mass spectrometry linked to high performance liquid chromatography (HPLC-ICPMS) is acknowledged as one of the most important tools for the trace analysis of metallic speciation because of its superior separation capability and detectability. However, the complexity of matrices can cause severe interferences in the analysis results, which is the problem often encountered with HPLC-ICPMS system. High concentration of organic carbon in a sample solution causes carbon build-up on the skimmer and sampling cone, which reduces analytical sensitivity and requires a high maintenance level for its cleaning. In addition, argon from the plasma and chlorine from the sample matrix may combine to form 40Ar35Cl, which has the same nominal mass to charge (m/z) ratio as arsenic. In this respect, analytical strategy for the determination of various arsenic species (e.g., inorganic arsenite and arsenate, monomethylarsonic acid, dimethylarsinic acid, dimethyldithioarsinic acid, and arsenobetaine) in landfill leachate containing high concentrations of chlorine and organic carbon was developed in the present study. Solid phase extraction disk (i.e., C18 disk), which does not significantly adsorb any target arsenic species, was used to remove organic carbon in sample solutions. In addition, helium (He) gas was injected into the collision reaction cell equipped in ICPMS to collapse 40Ar35Cl into individual 40Ar and 35Cl. Although He gas also decreased arsenic intensity by blocking 75As, its signal to noise ratio

  14. Ultrastructural and flow cytometric analyses of lipid accumulation in microalgae: Annual report, Solar Energy Research Institute, Aquatic Species Program

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, J.A.; Hand, R.E. Jr.; Mann, R.C.

    1986-01-01

    Lipid accumulation in three species of microalgae was investigated with flow cytometry (FCM) and transmission electron microscopy (TEM). Previous studies using batch cultures of algae have led to the assumption that lipid accumulation in microalgae is a gradual process requiring at least several days for completion. However, FCM reveals, through changes in the chlorophyll:lipid ratio, that the time span required for individual cells to change metabolic state is short. Simultaneous FCM measurements of chlorophyll and nile red (neutral lipid) fluorescence in individual cells of nitrogen-deficient Isochrysis populations revealed a bimodal population distribution as one stage in the lipid accumulation process. The fact that two discrete populations exist, with few cells in an intermediate stage, suggests rapid response to a lipid trigger. Interpretations of light and electron microscopic observations are consistent with this hypothesis. The time required for an entire population to achieve maximum lipid content is considerably longer than that required for a single cell, due to the variation in response time among cells. In this study high lipid cultures were sometimes obtained by using FCM to separate high lipid cells from the remainder of the population. FCM holds much promise for strain enhancement but considerable developmental work, directed at providing more consistent results, remains to be done. 8 refs., 33 figs.

  15. Optimization of a Nile Red method for rapid lipid determination in autotrophic, marine microalgae is species dependent.

    Science.gov (United States)

    Balduyck, Lieselot; Veryser, Cedrick; Goiris, Koen; Bruneel, Charlotte; Muylaert, Koenraad; Foubert, Imogen

    2015-11-01

    Several studies have been conducted to develop rapid methods for quantification of lipid content in microalgae, as an alternative for time consuming gravimetric methods. Different studies showed that lipid staining with Nile Red in whole cell suspensions and subsequently quantification by the use of a spectrofluorometric device is a promising method, but a profound optimization and validation is rare. It has already been proven that the correlation curve for quantification is species dependent, but it has not yet been investigated whether this is also the case for the optimization of the Nile Red assay protocol. Therefore, two autotrophic, marine microalgae, Nannochloropsis oculata and T-Isochrysis lutea, strongly differing in e.g. cell wall structure, were selected in this study to investigate whether optimization of the Nile Red assay is species dependent. Besides this, it was checked for one of these species, Nannochloropsis, whether the lipid content, determined by the Nile Red assay, could indeed be correlated with the neutral and/or total lipid content determined by gravimetric methods. It was found that optimization of the Nile Red assay was strongly species dependent. Consequently, optimization has to be done for each species before using the assay. For Nannochloropsis, a good correlation was found between total and neutral lipid content obtained by the Nile Red assay and by gravimetric methods.

  16. Characterization of a Native Algae Species Chlamydomonas debaryana: Strain Selection, Bioremediation Ability, and Lipid Characterization

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2014-08-01

    Full Text Available Native microalgal species may offer a favorable combination of both wastewater treatment and biofuel production. In this research, a green microalgae, Chlamydomonas debaryana, was isolated from a local lagoon, screened for its lipid content using flow cytometry, and further identified with microscopic observations and DNA sequence analysis. When using swine wastewater as a medium, the biomass yields were between 0.6 and 1.62 g/L, giving a median value of 1.11 g/L. By increasing mass transfer rates and providing sufficient light intensity, the microalgal growth was intrinsically enhanced. The growth of C. debaryana reduced most nutritional contents of the wastewater except iron. When combining the microalgal growth and nutrient removal, C. debaryana was able to utilize 1.3 to 1.6×103 mg COD (chemical oxygen demand/g biomass, 55 to 90 ppm ammonia/g biomass, and 48 to 89 ppm phosphorous/g biomass, The lipid content of C. debaryana was 19.9 ± 4.3% of cell dry weight. The transesterified microalgal oil mostly consisted of 14 kinds of fatty acids, ranging from C5 to C22, which can be refined into renewable jet fuel or used as sources of omega-3 and omega-6 fatty acids.

  17. Lipid Peroxidation and Antioxidative Enzymes of Two Turfgrass Species Under Salinity Stress

    Institute of Scientific and Technical Information of China (English)

    R.XU; M.YAMADA; H.FUJIYAMA

    2013-01-01

    Salinity stress is a major factor limiting the growth of turfgrass irrigated with recycled wastewater.The change in lipid peroxidation in terms of malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD),catalase (CAT),ascorbate peroxide (APX) and glutathione reductase (GR) in the shoots and roots of Kentucky bluegrass and tall fescue were investigated under salinity stress.Plants were subjected to 0,50,100,150 and 200 mmol L-1 NaCl for 40 d.The MDA content under salinity stress was lower in tall fescue than in Kentucky bluegrass in both shoots and roots.Activities of SOD in the shoots of both species increased with salinity stress.The activities of CAT and APX decreased in Kentucky bluegrass,but no significant difference in the activities of CAT and APX was observed in tall fescue.The activities of SOD,CAT and APX in the shoots of tall rescue were higher than those in Kentucky bluegrass.In the roots of Kentucky bluegrass,SOD and GR activities increased and CAT and APX activities decreased in comparison with the control.In the roots of tall rescue,salinity increased the activities of SOD,CAT,and APX.These results suggested that tall fescue exhibited a more effective protection mechanism and mitigated oxidative stress and lipid peroxidation by maintaining higher SOD,CAT and APX activities than Kentucky bluegrass.

  18. Variation in lipid extractability by solvent in microalgae. Additional criterion for selecting species and strains for biofuel production from microalgae.

    Science.gov (United States)

    Mendoza, Héctor; Carmona, Laura; Assunção, Patricia; Freijanes, Karen; de la Jara, Adelina; Portillo, Eduardo; Torres, Alicia

    2015-12-01

    The lipid extractability of 14 microalgae species and strains was assessed using organic solvents (methanol and chloroform). The high variability detected indicated the potential for applying this parameter as an additional criterion for microalgae screening in industrial processes such as biofuel production from microalgae. Species without cell walls presented higher extractability than species with cell walls. Analysis of cell integrity by flow cytometry and staining with propidium iodide showed a significant correlation between higher resistance to the physical treatments of cell rupture by sonication and the lipid extractability of the microalgae. The results highlight the cell wall as a determining factor in the inter- and intraspecific variability in lipid extraction treatments. Copyright © 2015. Published by Elsevier Ltd.

  19. Cadmium induces reactive oxygen species generation and lipid peroxidation in cortical neurons in culture.

    Science.gov (United States)

    López, E; Arce, C; Oset-Gasque, M J; Cañadas, S; González, M P

    2006-03-15

    Cadmium is a toxic agent that it is also an environmental contaminant. Cadmium exposure may be implicated in some humans disorders related to hyperactivity and increased aggressiveness. This study presents data indicating that cadmium induces cellular death in cortical neurons in culture. This death could be mediated by an apoptotic and a necrotic mechanism. The apoptotic death may be mediated by oxidative stress with reactive oxygen species (ROS) formation which could be induced by mitochondrial membrane dysfunction since this cation produces: (a) depletion of mitochondrial membrane potential and (b) diminution of ATP levels with ATP release. Necrotic death could be mediated by lipid peroxidation induced by cadmium through an indirect mechanism (ROS formation). On the other hand, 40% of the cells survive cadmium action. This survival seems to be mediated by the ability of these cells to activate antioxidant defense systems, since cadmium reduced the intracellular glutathione levels and induced catalase and SOD activation in these cells.

  20. Gaseous, chlorine-free chlorine dioxide for drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, G. [Miami Univ., Oxford, OH (United States); Rosenblatt, A. [CDG Technology Inc., New York, NY (United States)

    1996-11-01

    The benefits of applying chlorine dioxide (ClO{sub 2}) for the oxidative treatment of drinking water are well established. Chlorine dioxide treated finished water typically has substantially lower trihalomethane (THM) levels because ClO{sub 2} will not form chlorinated organic species as a by-product of disinfection. The THMs that are formed are probably due to chlorine from the generator or chlorine used to maintain a post-disinfection residual. An emerging regulatory issue concerning the formation of disinfection by-products (DBPs) is causing the water industry to set standards for the generation and delivery of ClO{sub 2}. The Federal Register (11 February 1994) contains language developed to limit the production of the unwanted inorganic by-products chlorite (ClO{sub 2}{sup -}), chlorate (ClO{sub 3}{sup -}), and bromate (BrO{sub 3}{sup -}) ions by requiring utilities to maintain high (95%) generation efficiencies and by limiting the amount of excess Cl{sub 2} that can be used during the generation process. The efficiency and excess Cl{sub 2} regulations may be problematic for utilities that over-chlorinate to attain chlorine dioxide high yields. Many utilities will have to decide either to reduce the amount of Cl{sub 2} used to react with sodium chlorite (NaClO{sub 2}), thereby increasing the ClO{sub 2}{sup -} residual in finished water, or over-chlorinate to increase yields and surpass the excess Cl{sub 2} limits.

  1. A comparative study on the effect of Curcumin and Chlorin-p6 on the diffusion of two organic cations across a negatively charged lipid bilayer probed by second harmonic spectroscopy

    Science.gov (United States)

    Saini, R. K.; Varshney, G. K.; Dube, A.; Gupta, P. K.; Das, K.

    2014-09-01

    The influence of Curcumin and Chlorin-p6 (Cp6) on the real time diffusion kinetics of two organic cations, LDS (LDS-698) and Malachite Green (MG) across a negatively charged phospholipid bilayer is investigated by Second Harmonic (SH) spectroscopy. The diffusion time constant of LDS at neutral pH in liposomes containing either Curcumin or Cp6 is significantly reduced, the effect being more pronounced with Curcumin. At acidic pH, the quantum of reduction in the diffusion time constant of MG by both the drugs was observed to be similar. The relative changes in the average diffusion time constants of the cations with increasing drug concentration at pH 5.0 and 7.4 shows a substantial pH effect for Curcumin induced membrane permeability, while a modest pH effect was observed for Cp6 induced membrane permeability. Based on available evidence this can be attributed to the increased interaction between the drug and the polar head groups of the lipid at pH 7.4 where the drug resides closer to the lipid-water interface.

  2. A Novel Approach to Prepare Well-Defined Silica-Supported Polyoxometalate Species by Reaction with a Chlorinated Support

    Directory of Open Access Journals (Sweden)

    Eva Grinenval

    2013-01-01

    Full Text Available Polyoxometalates were grafted covalently on SBA-15 by a two-step procedure. The dehydroxylated mesoporous silica was first modified by reaction with methyltrichlorosilane in presence of triethylamine. The resulting solid was fully characterized and contained a mixture of mono- and digrafted species . These surface Si–Cl bonds can react with lacunary polyoxometalates as in solution, yielding to a ≡Si–O–POM linkage. However, solid state MAS NMR shows that only the digrafted species react with the polyoxometalate. This new grafting method opens the way to the synthesis of a new class of catalysts which could operate in solution without leaching.

  3. Lipid Classes, Fatty Acid Composition, and Glycerolipid Molecular Species of the Red Alga Gracilaria vermiculophylla, a Prostaglandin-Producing Seaweed.

    Science.gov (United States)

    Honda, Masaki; Ishimaru, Takashi; Itabashi, Yutaka

    2016-01-01

    The red alga Gracilaria vermiculophylla is a well-known producer of prostaglandins, such as PGE2 and PGF2α. In this study, the characteristics of glycerolipids as substrates of prostaglandin production were clarified, and the lipid classes, fatty acid composition, and glycerolipid molecular species were investigated in detail. The major lipid classes were monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), and sulfoquinovosyldiacylglycerol (SQDG), as well as phosphatidylcholine (PC), which accounted for 43.0% of the total lipid profile. Arachidonic acid (20:4n-6), a prostaglandin precursor, and palmitic acid (16:0) were the predominant fatty acids in the total lipid profile. The 20:4n-6 content was significantly high in MGDG and PC (more than 60%), and the 16:0 content was significantly high in DGDG and SQDG (more than 50%). Chiral-phase high-performance liquid chromatography determined that fatty acids were esterified at the sn-1 and sn-2 positions of those lipids. The main glycerolipid molecular species were 20:4n-6/20:4n-6 (sn-1/sn-2) for MGDG (56.5%) and PC (40.0%), and 20:4n-6/16:0 for DGDG (75.4%) and SQDG (58.4%). Thus, it was considered that the glycerolipid molecular species containing one or two 20:4n-6 were the major substrates for prostaglandin production in G. vermiculophylla.

  4. Transformation of iopamidol during chlorination.

    Science.gov (United States)

    Wendel, Friedrich M; Lütke Eversloh, Christian; Machek, Edward J; Duirk, Stephen E; Plewa, Michael J; Richardson, Susan D; Ternes, Thomas A

    2014-11-01

    The transformation of the iodinated X-ray contrast media (ICM) iopamidol, iopromide, iohexol, iomeprol, and diatrizoate was examined in purified water over the pH range from 6.5 to 8.5 in the presence of sodium hypochlorite, monochloramine, and chlorine dioxide. In the presence of aqueous chlorine, only iopamidol was transformed. All other ICM did not show significant reactivity, regardless of the oxidant used. Chlorination of iopamidol followed a second order reaction, with an observed rate constant of up to 0.87 M(-1) s(-1) (±0.021 M(-1) s(-1)) at pH 8.5. The hypochlorite anion was identified to be the reactive chlorine species. Iodine was released during the transformation of iopamidol, and was mainly oxidized to iodate. Only a small percentage (less than 2% after 24 h) was transformed to known organic iodinated disinfection byproducts (DBPs) of low molecular weight. Some of the iodine was still present in high-molecular weight DBPs. The chemical structures of these DBPs were elucidated via MSn fragmentation and NMR. Side chain cleavage was observed as well as the exchange of iodine by chlorine. An overall transformation pathway was proposed for the degradation of iopamidol. CHO cell chronic cytotoxicity tests indicate that chlorination of iopamidol generates a toxic mixture of high molecular weight DBPs (LC50 332 ng/μL).

  5. MD-2 Residues Tyrosine 42, Arginine 69, Aspartic Acid 122, and Leucine 125 Provide Species Specificity for Lipid IVA*

    Science.gov (United States)

    Meng, Jianmin; Drolet, Joshua R.; Monks, Brian G.; Golenbock, Douglas T.

    2010-01-01

    Lipopolysaccharide (LPS) activates the innate immune response through the Toll-like receptor 4 (TLR4)·MD-2 complex. A synthetic lipid A precursor, lipid IVA, induces an innate immune response in mice but not in humans. Both TLR4 and MD-2 are required for the agonist activity of lipid IVA in mice, with TLR4 interacting through specific surface charges at the dimerization interface. In this study, we used site-directed mutagenesis to identify the MD-2 residues that determine lipid IVA species specificity. A single mutation of murine MD-2 at the hydrophobic pocket entrance, E122K, substantially reduced the response to lipid IVA. Combining the murine MD-2 E122K with the murine TLR4 K367E/S386K/R434Q mutations completely abolished the response to lipid IVA, effectively converting the murine cellular response to a human-like response. In human cells, however, simultaneous mutations of K122E, K125L, Y41F, and R69G on human MD-2 were required to promote a response to lipid IVA. Combining the human MD-2 quadruple mutations with the human TLR4 E369K/Q436R mutations completely converted the human MD-2/human TLR4 receptor to a murine-like receptor. Because MD-2 residues 122 and 125 reside at the dimerization interface near the pocket entrance, surface charge differences here directly affect receptor dimerization. In comparison, residues 42 and 69 reside at the MD-2/TLR4 interaction surface opposite the dimerization interface. Surface charge differences there likely affect the binding angle and/or rigidity between MD-2 and TLR4, exerting an indirect influence on receptor dimerization and activation. Thus, surface charge differences at the two MD-2/TLR4 interfaces determine the species-specific activation of lipid IVA. PMID:20592019

  6. The Search for a Lipid Trigger: The Effect of Salt Stress on the Lipid Profile of the Model Microalgal Species Chlamydomonas reinhardtii for Biofuels Production.

    Science.gov (United States)

    Hounslow, Emily; Kapoore, Rahul Vijay; Vaidyanathan, Seetharaman; Gilmour, D James; Wright, Phillip C

    2016-11-01

    Algal cells produce neutral lipid when stressed and this can be used to generate biodiesel. Salt stressed cells of the model microalgal species Chlamydomonas reinhardtii were tested for their suitability to produce lipid for biodiesel. The starchless mutant of C. reinhardtii (CC-4325) was subjected to salt stress (0.1, 0.2 and 0.3 M NaCl) and transesterification and GC analysis were used to determine fatty acid methyl ester (FAME) content and profile. Fatty acid profile was found to vary under salt stress conditions, with a clear distinction between 0.1 M NaCl, which the algae could tolerate, and the higher levels of NaCl (0.2 and 0.3 M), which caused cell death. Lipid content was increased under salt conditions, either through long-term exposure to 0.1 M NaCl, or short-term exposure to 0.2 and 0.3 M NaCl. Palmitic acid (C16:0) and linolenic acid (C18:3n3) were found to increase significantly at the higher salinities. Salt increase can act as a lipid trigger for C. reinhardtii.

  7. Stress induced lipid production in Chlorella vulgaris: relationship with specific intracellular reactive species levels.

    Science.gov (United States)

    Menon, Kavya R; Balan, Ranjini; Suraishkumar, G K

    2013-06-01

    Microalgae have significant potential to be an important alternative energy source, but the challenges to the commercialization of bio-oil from microalgae need to be overcome for the potential to be realized. The application of stress can be used to improve bio-oil yields from algae. Nevertheless, the understanding of stress effects is fragmented due to the lack of a suitable, direct quantitative marker for stress. The lack of understanding seems to have limited the development of stress based strategies to improve bio-oil yields, and hence the commercialization of microalgae-based bio-oil. In this study, we have proposed and used the specific intracellular reactive species levels (siROS) particularly hydroxyl and superoxide radical levels, separately, as direct, quantitative, markers for stress, irrespective of the type of stress induced. Although ROS reactions are extremely rapid, the siROS level can be assumed to be at pseudo-steady state compared to the time scales of metabolism, growth and production, and hence they can be effective stress markers at particular time points. Also, the specific intracellular (si-) hydroxyl and superoxide radical levels are easy to measure through fluorimetry. Interestingly, irrespective of the conditions employed in this study, that is, nutrient excess/limitation or different light wavelengths, the cell concentrations are correlated to the siROS levels in an inverse power law fashion. The composite plots of cell concentration (y) and siROS (x) yielded the correlations of y = k1  · x(-0.7) and y = k2  · x(-0.79) , for si-hydroxyl and si-superoxide radical levels, respectively. The specific intracellular (si-) neutral lipid levels, which determine the bio-oil productivity, are related in a direct power law fashion to the specific hydroxyl radical levels. The composite plot of si-neutral lipid levels (z) and si-hydroxyl radical level (x) yielded a correlation of z = k3  · x(0.65) . More interestingly, a

  8. UVA photoirradiation of nitro-polycyclic aromatic hydrocarbons-induction of reactive oxygen species and formation of lipid peroxides.

    Science.gov (United States)

    Xia, Qingsu; Yin, Jun-Jie; Zhao, Yuewei; Wu, Yuh-Sen; Wang, Yu-Qui; Ma, Liang; Chen, Shoujun; Sun, Xin; Fu, Peter P; Yu, Hongtao

    2013-03-14

    Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) are a class of genotoxic environmental contaminants. We have long been interested in determining the mechanisms by which nitro-PAHs induce genotoxicity. Although the metabolic activation of nitro-PAHs leading to toxicological activities has been well studied, the photo-induced activation of nitro-PAHs has seldom been reported. In this paper, we report photo-induced lipid peroxidation by 19 nitro-PAHs. The results indicated that all but two of the nitro-PAHs can induce lipid peroxidation. Mechanistic studies suggest that lipid peroxidation by nitro-PAHs is mediated by free radicals generated in the reaction. There was no structural correlation between the nitro-PAHs and their ability to induce lipid peroxidation upon UVA irradiation, or between the HOMO-LUMO gap and the ability to cause lipid peroxidation. Most of the nitro-PAHs are less potent in terms of causing lipid peroxidation than their parent PAHs. The lack of correlation is attributed to the complex photophysics and photochemistry of the nitro-PAHs and the yield of reactive oxygen species (ROS) and other factors.

  9. UVA Photoirradiation of Nitro-Polycyclic Aromatic Hydrocarbons—Induction of Reactive Oxygen Species and Formation of Lipid Peroxides †

    Science.gov (United States)

    Xia, Qingsu; Yin, Jun J.; Zhao, Yuewei; Wu, Yuh-Sen; Wang, Yu-Qui; Ma, Liang; Chen, Shoujun; Sun, Xin; Fu, Peter P.; Yu, Hongtao

    2013-01-01

    Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) are a class of genotoxic environmental contaminants. We have long been interested in determining the mechanisms by which nitro-PAHs induce genotoxicity. Although the metabolic activation of nitro-PAHs leading to toxicological activities has been well studied, the photo-induced activation of nitro-PAHs has seldom been reported. In this paper, we report photo-induced lipid peroxidation by 19 nitro-PAHs. The results indicated that all but two of the nitro-PAHs can induce lipid peroxidation. Mechanistic studies suggest that lipid peroxidation by nitro-PAHs is mediated by free radicals generated in the reaction. There was no structural correlation between the nitro-PAHs and their ability to induce lipid peroxidation upon UVA irradiation, or between the HOMO-LUMO gap and the ability to cause lipid peroxidation. Most of the nitro-PAHs are less potent in terms of causing lipid peroxidation than their parent PAHs. The lack of correlation is attributed to the complex photophysics and photochemistry of the nitro-PAHs and the yield of reactive oxygen species (ROS) and other factors. PMID:23493032

  10. Starch and lipid accumulation in eight strains of six Chlorella species under comparatively high light intensity and aeration culture conditions.

    Science.gov (United States)

    Takeshita, Tsuyoshi; Ota, Shuhei; Yamazaki, Tomokazu; Hirata, Aiko; Zachleder, Vilém; Kawano, Shigeyuki

    2014-04-01

    The microalgae family Chlorella species are known to accumulate starch and lipids. Although nitrogen or phosphorous deficiencies promote starch and lipids formation in many microalgae, these deficiencies also limit their growth and productivity. Therefore, the Chlorellaceae strains were attempted to increase starch and lipids productivity under high-light-intensity conditions (600-μmol photons m(-2)s(-1)). The 12:12-h light-dark (LD) cycle conditions elicited more stable growth than the continuous light (LL) conditions, whereas the starch and lipids yields increased in LL conditions. The amount of starch and lipids per cell increased in Chlorella viscosa and Chlorella vulgaris in sulfur-deficient medium, and long-chain fatty acids with 20 or more carbon atoms accumulated in cells grown in sulfur-deficient medium. Accumulation of starch and lipids was investigated in eight strains. The accumulation was strain-dependent, and varied according to the medium and light conditions. Five of the eight Chlorella strains exhibited similar accumulation patterns.

  11. Dietary Conjugated Linoleic Acid and Hepatic Steatosis: Species-Specific Effects on Liver and Adipose Lipid Metabolism and Gene Expression

    Directory of Open Access Journals (Sweden)

    Diwakar Vyas

    2012-01-01

    Full Text Available Objective. To summarize the recent studies on effect of conjugated linoleic acid (CLA on hepatic steatosis and hepatic and adipose lipid metabolism highlighting the potential regulatory mechanisms. Methods. Sixty-four published experiments were summarized in which trans-10, cis-12 CLA was fed either alone or in combination with other CLA isomers to mice, rats, hamsters, and humans were compared. Summary and Conclusions. Dietary trans-10, cis-12 CLA induces a severe hepatic steatosis in mice with a more muted response in other species. Regardless of species, when hepatic steatosis was present, a concurrent decrease in body adiposity was observed, suggesting that hepatic lipid accumulation is a result of uptake of mobilized fatty acids (FA from adipose tissue and the liver's inability to sufficiently increase FA oxidation and export of synthesized triglycerides. The potential role of liver FA composition, insulin secretion and sensitivity, adipokine, and inflammatory responses are discussed as potential mechanisms behind CLA-induced hepatic steatosis.

  12. Replacement of retinyl esters by polyunsaturated triacylglycerol species in lipid droplets of hepatic stellate cells during activation.

    Directory of Open Access Journals (Sweden)

    Nicole Testerink

    Full Text Available Activation of hepatic stellate cells has been recognized as one of the first steps in liver injury and repair. During activation, hepatic stellate cells transform into myofibroblasts with concomitant loss of their lipid droplets (LDs and production of excessive extracellular matrix. Here we aimed to obtain more insight in the dynamics and mechanism of LD loss. We have investigated the LD degradation processes in rat hepatic stellate cells in vitro with a combined approach of confocal Raman microspectroscopy and mass spectrometric analysis of lipids (lipidomics. Upon activation of the hepatic stellate cells, LDs reduce in size, but increase in number during the first 7 days, but the total volume of neutral lipids did not decrease. The LDs also migrate to cellular extensions in the first 7 days, before they disappear. In individual hepatic stellate cells. all LDs have a similar Raman spectrum, suggesting a similar lipid profile. However, Raman studies also showed that the retinyl esters are degraded more rapidly than the triacylglycerols upon activation. Lipidomic analyses confirmed that after 7 days in culture hepatic stellate cells have lost most of their retinyl esters, but not their triacylglycerols and cholesterol esters. Furthermore, we specifically observed a large increase in triacylglycerol-species containing polyunsaturated fatty acids, partly caused by an enhanced incorporation of exogenous arachidonic acid. These results reveal that lipid droplet degradation in activated hepatic stellate cells is a highly dynamic and regulated process. The rapid replacement of retinyl esters by polyunsaturated fatty acids in LDs suggests a role for both lipids or their derivatives like eicosanoids during hepatic stellate cell activation.

  13. Comprehensive and quantitative profiling of lipid species in human milk, cow milk and a phospholipid-enriched milk formula by GC and MS/MSALL

    OpenAIRE

    Sokol, Olena; Ulven, Trond; Færgeman, Nils J.; Ejsing, Christer S.

    2015-01-01

    Here we present a workflow for in-depth analysis of milk lipids that combines gas chromatography (GC) for fatty acid (FA) profiling and a shotgun lipidomics routine termed MS/MSALL for structural characterization of molecular lipid species. To evaluate the performance of the workflow we performed a comparative lipid analysis of human milk, cow milk, and Lacprodan® PL-20, a phospholipid-enriched milk protein concentrate for infant formula. The GC analysis showed that human milk and Lacprodan h...

  14. Nitrogen starvation for lipid accumulation in the microalga species Desmodesmus sp.

    Science.gov (United States)

    Rios, L F; Klein, B C; Luz, L F; Maciel Filho, R; Wolf Maciel, M R

    2015-01-01

    Recently, to obtain lipids from microalgae has been the object of extensive research, since it is viewed as a promising feedstock for biodiesel production, especially when compared with crops such as soybean and sunflower, in terms of theoretical performance. The reduction of nutrient availability in culture media, especially nitrogen, stresses the microorganisms and affects cell growth, thus inducing lipid accumulation. This is an interesting step in biodiesel feedstock obtention from microalgae and should be better understood. In this study, four levels of nitrogen concentration in the BG-11 culture medium were evaluated in the growth of the chlorophycean microalga Desmodesmus sp. Both cell growth and lipid content were monitored over 7 days of cultivation, which yielded a final cell density of 33 × 10(6) cells mL(-1) with an initial NaNO3 concentration of 750 mg L(-1) in the medium and a maximum lipid content of 23 % with total nitrogen starvation. It was observed that the microalgae presented high lipid accumulation in the fourth day of cultivation with nitrogen starvation, although with moderate cell growth.

  15. Reactive Oxygen Species-Induced TXNIP Drives Fructose-Mediated Hepatic Inflammation and Lipid Accumulation Through NLRP3 Inflammasome Activation

    Science.gov (United States)

    Zhang, Xian; Zhang, Jian-Hua; Chen, Xu-Yang; Hu, Qing-Hua; Wang, Ming-Xing; Jin, Rui; Zhang, Qing-Yu; Wang, Wei; Wang, Rong; Kang, Lin-Lin; Li, Jin-Sheng; Li, Meng

    2015-01-01

    Abstract Aims: Increased fructose consumption predisposes the liver to nonalcoholic fatty liver disease (NAFLD), but the mechanisms are elusive. Thioredoxin-interacting protein (TXNIP) links oxidative stress to NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation and this signaling axis may be involved in fructose-induced NAFLD. Here, we explore the role of reactive oxygen species (ROS)-induced TXNIP overexpression in fructose-mediated hepatic NLRP3 inflammasome activation, inflammation, and lipid accumulation. Results: Rats were fed a 10% fructose diet for 8 weeks and treated with allopurinol and quercetin during the last 4 weeks. Five millimolars of fructose-exposed hepatocytes (primary rat hepatocytes, rat hepatic parenchymal cells [RHPCs], HLO2, HepG2) were co-incubated with antioxidants or caspase-1 inhibitor or subjected to TXNIP or NLRP3 siRNA interference. Fructose induced NLRP3 inflammasome activation and pro-inflammatory cytokine secretion, janus-activated kinase 2/signal transducers and activators of transcription 3-mediated inflammatory signaling, and expression alteration of lipid metabolism-related genes in cultured hepatocytes and rat livers. NLRP3 silencing and caspase-1 suppression blocked these effects in primary rat hepatocytes and RHPCs, confirming that inflammasome activation alters hepatocyte lipid metabolism. Hepatocellular ROS and TXNIP were increased in animal and cell models. TXNIP silencing blocked NLRP3 inflammasome activation, inflammation, and lipid metabolism perturbations but not ROS induction in fructose-exposed hepatocytes, whereas antioxidants addition abrogated TXNIP induction and diminished the detrimental effects in fructose-exposed hepatocytes and rat livers. Innovation and Conclusions: This study provides a novel mechanism for fructose-induced NAFLD pathogenesis by which the ROS-TXNIP pathway mediates hepatocellular NLRP3 inflammasome activation, inflammation and lipid accumulation. Antioxidant

  16. Non-Saponifiable Lipid Composition of Four Salt-Secretor and Non-Secretor Mangrove Species from North Sumatra, Indonesia

    Directory of Open Access Journals (Sweden)

    Julayha

    2012-08-01

    Full Text Available Non-saponifiable lipid (NSL of the fresh leaves and roots from two salt-secretor mangrove species, namely Aegiceras corniculatum (L. Blanco and Avicennia alba Bl. and two non-secretor mangroves, i.e. Acrostichum aureum L. and Excoecaria agallocha L. was analyzed with special emphasize to triterpenoids and phytosterols. Identification of the triterpenoids and phytosterols was confirmed by comparison of their retention time on the GC column with those of authentic standards and on the interpretation of GC-MS spectra. Triterpenoids and phytosterols comprised the major proportion of NSL. The triterpenoids and phytosterols mainly consisted of 7 and 4 compounds. Triterpenoids were the largest constituent of Ac. aureum and Ae. corniculatum leaves and roots, and E. agallocha roots. In contrast to these triterpenoids-rich species, phytosterols were relatively dominant in the roots of Av. alba. The species of Av. alba and E. agallocha in the leaves were distinguished from the others in that both species contained a larger quantity of phytol. Ae. corniculatum contained a large amount of betulin and α-amyrin in the roots, as well as lupeol in the roots of Av. alba. The diversity in the NSL composition noted with mangrove species in both the leaves and roots suggested that NSL of mangrove leaves and roots can be used as chemotaxonomical character to differentiate species.

  17. Simultaneous increases in specific growth rate and specific lipid content of Chlorella vulgaris through UV-induced reactive species.

    Science.gov (United States)

    Balan, Ranjini; Suraishkumar, G K

    2014-01-01

    A challenge in algae-based bio-oil production is to simultaneously enhance specific growth rates and specific lipid content. We have demonstrated simultaneous increases in both the above in Chlorella vulgaris through reactive species (RS) induced under ultraviolet (UV) A and UVB light treatments. We postulated that the changes in photosystem (PS) stoichiometry and antenna size were responsible for the increases in specific growth rate. UVB treatment excited PSII, which resulted in a twofold to sevenfold increase in PSII/PSI ratio compared to control. An excited PSII caused a 2.7-fold increase in the specific levels of superoxide and a twofold increase in the specific levels of hydroxyl radicals. We have established that the increased specific intracellular RS (si-RS) levels increased the PSII antenna size by a significant 10-fold as compared to control. In addition, the 8.2-fold increase in specific lipid content was directly related to the si-RS levels. We have also demonstrated that the RS induced under UVA treatment led to a 3.2-fold increase in the saturated to unsaturated fatty acid ratio. Based on the findings, we have proposed and demonstrated a UV-based strategy, which achieved an 8.8-fold increase in volumetric lipid productivity.

  18. Neutral lipid accumulation at elevated temperature in conditional mutants of two microalgae species

    DEFF Research Database (Denmark)

    Yao, Shuo; Brandt, Anders Bøving; Egsgaard, Helge

    2012-01-01

    Triacylglycerols, an energy storage compound in microalgae, are known to be accumulated after nitrogen starvation of microalgae cells. Microalgae could be of importance for future biodiesel production due to their fast growth rate and high oil content. In collections of temperature sensitive...... accumulation in microalgae and suggest possibilities for biodiesel production by specific induction of lipid accumulation in miroalgal cultures by cell-cycle inhibition....

  19. Comprehensive and quantitative profiling of lipid species in human milk, cow milk and a phospholipid-enriched milk formula by GC and MS/MSALL

    Science.gov (United States)

    Sokol, Elena; Ulven, Trond; Færgeman, Nils J; Ejsing, Christer S

    2015-01-01

    Here we present a workflow for in-depth analysis of milk lipids that combines gas chromatography (GC) for fatty acid (FA) profiling and a shotgun lipidomics routine termed MS/MSALL for structural characterization of molecular lipid species. To evaluate the performance of the workflow we performed a comparative lipid analysis of human milk, cow milk, and Lacprodan® PL-20, a phospholipid-enriched milk protein concentrate for infant formula. The GC analysis showed that human milk and Lacprodan have a similar FA profile with higher levels of unsaturated FAs as compared to cow milk. In-depth lipidomic analysis by MS/MSALL revealed that each type of milk sample comprised distinct composition of molecular lipid species. Lipid class composition showed that the human and cow milk contain a higher proportion of triacylglycerols (TAGs) as compared to Lacprodan. Notably, the MS/MSALL analysis demonstrated that the similar FA profile of human milk and Lacprodan determined by GC analysis is attributed to the composition of individual TAG species in human milk and glycerophospholipid species in Lacprodan. Moreover, the analysis of TAG molecules in Lacprodan and cow milk showed a high proportion of short-chain FAs that could not be monitored by GC analysis. The results presented here show that complementary GC and MS/MSALL analysis is a powerful approach for characterization of molecular lipid species in milk and milk products. Practical applications : Milk lipid analysis is routinely performed using gas chromatography. This method reports the total fatty acid composition of all milk lipids, but provides no structural or quantitative information about individual lipid molecules in milk or milk products. Here we present a workflow that integrates gas chromatography for fatty acid profiling and a shotgun lipidomics routine termed MS/MSALL for structural analysis and quantification of molecular lipid species. We demonstrate the efficacy of this complementary workflow by a

  20. Quantitative profiling of PE, MMPE, DMPE, and PC lipid species by multiple precursor ion scanning: A tool for monitoring PE metabolism

    DEFF Research Database (Denmark)

    Bilgin, Mesut; Markgraf, Daniel F; Duchoslav, Eva

    2011-01-01

    We report a method for the simultaneous identification and quantification of phosphatidylethanolamine (PE), monomethyl-phosphatidylethanolamine (MMPE), dimethyl-phosphatidylethanolamine (DMPE), and phosphatidylcholine (PC) species in lipid extracts. The method employs a specific "mass-tag" strategy...... metabolism in Saccharomyces cerevisiae. Finally, we benchmarked the mass-tag strategy by specific and sensitive profiling of intermediate MMPE and DMPE species in liver....

  1. Enhancement of Muscle Mitochondrial Oxidative Capacity and Alterations in Insulin Action Are Lipid Species Dependent

    OpenAIRE

    Turner, Nigel; Hariharan, Krit; TidAng, Jennifer; Frangioudakis, Georgia; Beale, Susan M.; Wright, Lauren E.; Zeng, Xiao Yi; Leslie, Simon J; LI Jing-ya; Kraegen, Edward W.; Cooney, Gregory J.; Ye, Ji-Ming

    2009-01-01

    OBJECTIVE Medium-chain fatty acids (MCFAs) have been reported to be less obesogenic than long-chain fatty acids (LCFAs); however, relatively little is known regarding their effect on insulin action. Here, we examined the tissue-specific effects of MCFAs on lipid metabolism and insulin action. RESEARCH DESIGN AND METHODS C57BL6/J mice and Wistar rats were fed either a low-fat control diet or high-fat diets rich in MCFAs or LCFAs for 4–5 weeks, and markers of mitochondrial oxidative capacity, l...

  2. Comprehensive and quantitative profiling of lipid species in human milk, cow milk and a phospholipid-enriched milk formula by GC and MS/MSALL

    DEFF Research Database (Denmark)

    Sokol, Olena; Ulven, Trond; Færgeman, Nils J.

    2015-01-01

    Here we present a workflow for in-depth analysis of milk lipids that combines gas chromatography (GC) for fatty acid (FA) profiling and a shotgun lipidomics routine termed MS/MSALL for structural characterization of molecular lipid species. To evaluate the performance of the workflow we performed...... a comparative lipid analysis of human milk, cow milk, and Lacprodan® PL-20, a phospholipid-enriched milk protein concentrate for infant formula. The GC analysis showed that human milk and Lacprodan have a similar FA profile with higher levels of unsaturated FAs as compared to cow milk. In-depth lipidomic....... This method reports the total fatty acid composition of all milk lipids, but provides no structural or quantitative information about individual lipid molecules in milk or milk products. Here we present a workflow that integrates gas chromatography for fatty acid profiling and a shotgun lipidomics routine...

  3. Comparison of lipid membrane-water partitioning with various organic solvent-water partitions of neutral species and ionic species: Uniqueness of cerasome as a model for the stratum corneum in partition processes.

    Science.gov (United States)

    Zhang, Keda; Fahr, Alfred; Abraham, Michael H; Acree, William E; Tobin, Desmond J; Liu, Xiangli

    2015-10-15

    Lipid membrane-water partitions (e.g., immobilized artificial membrane systems where the lipid membrane is a neutral phospholipid monolayer bound to gel beads) were compared to various organic solvent-water partitions using linear free energy relationships. To this end, we also measured the retention factors of 36 compounds (including neutral and ionic species) from water to liposomes made up of 3-sn-phosphatidylcholine and 3-sn-phosphatidyl-l-serine (80:20, mol/mol), employing liposome electrokinetic chromatography in this work. The results show that lipid membranes exhibit a considerably different chemical environment from those of organic solvents. For both neutral species and ionic species, partitions into the more polar hydroxylic solvents are chemically closer to partition into the lipid membrane as compared to partitions into the less polar hydroxylic solvents and into aprotic solvents. This means that solutes partition into the polar parts of lipid membranes, regardless of whether they are charged or not. In addition, cerasome (i.e., liposome composed mainly of stratum corneum lipids) was compared with regular phospholipid liposomes as a possible model for human stratum corneum in partitions. It was found that the cerasome-water partition exhibits a better chemical similarity to skin permeation. This is probably due to the unique structures of ceramides that occur in cerasome and in the stratum corneum lipid domain. We further show that membranes in membrane-water partitions exhibit very different properties.

  4. Water Treatment Technology - Chlorination.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chlorination provides instructional materials for nine competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purpose and process of chlorination, chlorine…

  5. Live-cell quantification and comparison of mammalian oocyte cytosolic lipid content between species, during development, and in relation to body composition using nonlinear vibrational microscopy.

    Science.gov (United States)

    Jasensky, Joshua; Boughton, Andrew P; Khmaladze, Alexander; Ding, Jun; Zhang, Chi; Swain, Jason E; Smith, George W; Chen, Zhan; Smith, Gary D

    2016-08-01

    Cytosolic lipids participate in the growth, development, and overall health of mammalian oocytes including many roles in cellular homeostasis. Significant emphasis has been placed on the study of lipids as a dynamic organelle, which in turn requires the development of tools and techniques to quantitate and compare how lipid content relates to cellular structure, function, and normalcy. Objectives of this study were to determine if nonlinear vibrational microscopy (e.g., coherent anti-Stokes Raman scattering or CARS microscopy) could be used for live-cell imaging to quantify and compare lipid content in mammalian oocytes during development and in relation to body composition; and compare its efficacy to methods involving cellular fixation and staining protocols. Results of this study demonstrate that CARS is able to identify lipids in live mammalian oocytes, and there exists quantifiable and consistent differences in percent lipid composition across ooctyes of different species, developmental stages, and in relation to body composition. Such a method of live-cell lipid quantification has (i) experimental power in basic cell biology, (ii) practical utility for identifying developmental predictive biomarkers while advancing biology-based oocyte/embryo selection, and (iii) ability to yield rationally supporting technology for decision-making in rodents, domestic species, and human assisted reproduction and/or fertility preservation.

  6. Reactive Oxygen Species-Mediated Cellular Stress Response and Lipid Accumulation in Oleaginous Microorganisms: The State of the Art and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Xiao-Jun Ji

    2017-05-01

    Full Text Available Microbial oils, which are mainly extracted from yeasts, molds, and algae, have been of considerable interest as food additives and biofuel resources due to their high lipid content. While these oleaginous microorganisms generally produce only small amounts of lipids under optimal growth conditions, their lipid accumulation machinery can be induced by environmental stresses, such as nutrient limitation and an inhospitable physical environmental. As common second messengers of many stress factors, reactive oxygen species (ROS may act as a regulator of cellular responses to extracellular environmental signaling. Furthermore, increasing evidence indicates that ROS may act as a mediator of lipid accumulation, which is associated with dramatic changes in the transcriptome, proteome, and metabolome. However, the specific mechanisms of ROS involvement in the crosstalk between extracellular stress signaling and intracellular lipid synthesis require further investigation. Here, we summarize current knowledge on stress-induced lipid biosynthesis and the putative role of ROS in the control of lipid accumulation in oleaginous microorganisms. Understanding such links may provide guidance for the development of stress-based strategies to enhance microbial lipid production.

  7. Long-lived reactive species formed on proteins induce changes in protein and lipid turnover.

    Science.gov (United States)

    Davies, Michael

    2014-10-01

    Proteins are major targets for oxidative damage in vivo due to their high abundance and rapid rates of reaction with both one-electron (radical) and two-electron oxidants (e.g. singlet oxygen, hypochlorous acid, peroxynitrous acid, reactive aldehydes). The turnover of both native and modified proteins is critical for maintenance of cell homeostasis, with this occurring via multiple pathways including proteasomes (for cytosolic species), the Lon protease (in mitochondria), and the endo-lysosomal systems (both extra- and intra-cellular species). Evidence has been presented for both enhanced and diminished rates of catabolism of modified proteins, as well as altered turnover of native (unmodified) proteins as a result of damage to these systems, potentially as a result of the accumulation of damaged proteins. In recent studies we have shown that long-lived reactive species forms on proteins (hydroperoxides, chloramines and aldehydes) can modify the activity of proteasomal and lysosomal enzymes. Some of the above species are efficient inhibitors of the tryptic and chymotryptic activities of the 26S proteasome, as well as lysosomal cathepsin and acid lipase activities. These are key species in the turnover of both proteins and lipoproteins. The loss of enzyme activity is accompanied in many cases, by oxidation of critical thiol residues via molecular reactions. For reactive aldehydes (either free or protein-bound) direct enzyme inhibition can occur as well as modulation of protein levels and, in the case of lysosomes, changes in lysosomal numbers. Overall, these data indicate that the formation of reactive species on proteins can modulate cell function by multiple pathways including interference with the turnover of native proteins (including critical cell signalling molecules) and alterations in the rate of clearance of modified proteins. Both pathways may contribute to the development of a number of human pathologies associated with oxidative damage.

  8. Mass cultivation of various algal species and their evaluation as a potential candidate for lipid production.

    Science.gov (United States)

    Sharif, Nadia; Munir, Neelma; Saleem, Faiza; Aslam, Farheen; Naz, Shagufta

    2015-01-01

    Microalgae have been proposed as a promising source for biodiesel production. Focusing on algal strains for biodiesel production, efforts should be made to search new strains. Experiments were carried out to investigate the effects of growth parameters (nutrients, pH, light, aeration and temperature) and the oil percentage of eight algal strains (Chlorella sp., Cladophora sp., Hydrodictylium sp., Oedogonium sp., Oscillatoria sp., Spirogyra sp., Stigeocolonium sp., Ulothrix sp.). Results show that 6.5-7.5 is the optimum pH for the growth of all algal species. Temperature showed a greater variation (25°40°C). Ulothrix sp. gave more biomass productivity and is the most suitable strain for biodiesel production due to higher oil percentage (62%). Least biomass production was observed for Stigeocolonium sp. and least oil content was obtained from Hydrodictylium sp. It was observed that among these eight algal strains for biodiesel production, Ulothrix and Chlorella are the most promising algae species.

  9. Chlorination of Pyridinium Compounds

    Science.gov (United States)

    Daumer, Kathleen M.; Khan, Ahsan U.; Steinbeck, Marla J.

    2010-01-01

    Reactive oxygen species produced by activated neutrophils and monocytes are thought to be involved in mediating the loss of collagen and other matrix proteins at sites of inflammation. To evaluate their potential to oxidize the pyridinoline (Pyd) cross-links found in collagen types I and II, we reacted hydrogen peroxide (H2O2), hypochlorous acid/hypochlorite (HOCl/OCl−), and singlet oxygen (O2(1Δg)) with the Pyd substitutes, pyridoxamine dihydrochloride and vitamin B6, which share the same chemical structure and spectral properties of Pyd cross-links. Neither H2O2 (125–500 µm) nor O2(1Δg) (10–25 µm) significantly changed the spectral properties of pyridoxamine or vitamin B6. Reaction of HOCl/OCl− (12.5–50 µm) with pyridoxamine at pH 7.2 resulted in a concentration-dependent appearance of two new absorbance peaks and a decrease in fluorescence at 400 nm (excitation 325 nm). The new absorbance peaks correlated with the formation of an N-chloramine and the product of its subsequent reaction with pyridoxamine. In contrast, the extent to which HOCl reacted with vitamin B6, which lacks a primary amine group, was variable at this pH. At lysosomal pH 5.5, Cl2/HOCl/OCl− reacted with both pyridoxamine and vitamin B6. Four of the chlorinated products of this reaction were identified by gas chromatography-mass spectrometry and included 3-chloropyridinium, an aldehyde, and several chlorinated products with disrupted rings. To evaluate the effects of Cl2/HOCl/OCl− on Pyd cross-links in collagen, we exposed bone collagen type I and articular cartilage type II to HOCl. Treatment of either collagen type with HOCl at pH 5.0 or 7.2 resulted in the oxidation of amine groups and, for collagen type II, the specific decrease in Pyd cross-link fluorescence, suggesting that during inflammation both oxidations may be used by neutrophils and monocytes to promote the loss of matrix integrity. PMID:10940296

  10. Reaction products of chlorine dioxide.

    OpenAIRE

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxi...

  11. Reaction products of chlorine dioxide.

    OpenAIRE

    Stevens, A. A.

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxi...

  12. An allometric study of fatty acids and sensitivity to lipid peroxidation of brain microsomes and mitochondria isolated from different bird species.

    Science.gov (United States)

    Gutiérrez, A M; Reboredo, G R; Mosca, S M; Catalá, A

    2008-07-01

    The objective of this investigation was to examine the relationship between body size, fatty acid composition and sensitivity to lipid peroxidation of mitochondria and microsomes isolated from the brain of different size bird species: manon, quail, pigeon, duck and goose, representing a 372-fold range of body mass. Fatty acids of total lipids were determined using gas chromatography and lipid peroxidation was evaluated using a chemiluminescence assay. The allometric study of the fatty acids present in brain mitochondria and microsomes of the different bird species showed a small number of significant allometric trends. In mitochondria the percentage of monounsaturated fatty acids, was significantly lower in the larger birds (r=-0.965; Pmicrosomes but not in mitochondria may indicate a preferential incorporation of this fatty acid in the brain endoplasmic reticulum of the larger bird species. The brain of all birds studied had a high content of docosahexaenoic acid. However brain mitochondria but not microsomes isolated from all the birds analyzed showed a significant decrease of arachidonic and docosahexaenoic acids during lipid peroxidation. The allometric analyses of chemiluminescence were not statistically significant. In conclusion our results show absence of correlation between the sensitivity to lipid peroxidation of brain mitochondria and microsomes with body size and maximum life span.

  13. Lipid composition and antioxidant activities of the seed oil from three Mlvaceae species

    Directory of Open Access Journals (Sweden)

    Tešević V.

    2012-01-01

    Full Text Available The oil content and fatty acids, unsaponifiable composition and antioxidant activities of the seed oil from three Malvaceae species (Malva sylvestris L., Malva sylvestris L. var. mauritiana and Althaea officinalis L. from Serbia were determined. The oil yields from the seeds varied from 7.18 to 9.60%. The main fatty acids of the seed oils were linoleic acid (44.14-54.49%, oleic acid (13.00-16.99% and palmitic acid (11.45-24.29%. A small amount of cyclopropenoid acids, up to 1.85% was also established. The predominant sterol in all seed oils was β-sitosterol (11.51-17.34 mg/g of oil. The antioxidant potential of all the investigated seed oils was evaluated by radical scavenging activity using 2,2-diphenyl-1- picrylhydrazyl (DPPH assay.

  14. Chlorinated and nitrogenous disinfection by-product formation from ozonation and post-chlorination of natural organic matter surrogates.

    Science.gov (United States)

    Bond, Tom; Templeton, Michael R; Rifai, Omar; Ali, Hussain; Graham, Nigel J D

    2014-09-01

    Ozonation before chlorination is associated with enhanced formation of chloropicrin, a halonitromethane disinfection by-product (DBP), during drinking water treatment. In order to elucidate reasons for this, five natural organic matter (NOM) surrogates were treated using both chlorination and ozonation-chlorination under controlled laboratory conditions. Selected surrogates comprised two phenolic compounds, two free amino acids and one dipeptide; these were resorcinol, 3-aminophenol, L-aspartic acid, β-alanine and ala-ala, respectively. Quantified DBPs included chloropicrin, chloroform, dichloroacetonitrile and trichloroacetonitrile. Relative to chlorination alone, increases in the formation of chloropicrin from ozonation-chlorination varied from 138% for 3-aminophenol to 3740% for ala-ala for the four amine surrogates. This indicates that ozone is more effective than chlorine in mediating a rate-limiting oxidation step in chloropicrin formation, most plausibly involving conversion of an amine group to a nitro group. While both hydrophilic and hydrophobic surrogates acted as chloropicrin precursors, ala-ala was the most reactive precursor following ozonation-chlorination. Since peptides are far commoner in drinking water sources than free amino acids, further research into chemical oxidation of these species by ozone and chlorine is recommended. In contrast, oxidation with ozone prior to chlorination reduced chloroform formation moderately for the two phenolic compounds.

  15. Interspecific variation in vitamin E levels and the extent of lipid peroxidation in pioneer and non-pioneer species used in tropical forest restoration.

    Science.gov (United States)

    Contin, Daniele R; Munné-Bosch, Sergi

    2016-09-01

    Reforestation projects have gained interest over recent years due to the loss of biodiversity in tropical regions as a result of large deforestation by anthropogenic actions. However, better knowledge on the tolerance of plant species to environmental stresses is needed for reforestation success. Here, we evaluated the photoprotective and antioxidant capacity, in terms of vitamin E accumulation, of five pioneer (Platypodium elegans Vogel, Schinus terebinthifolius Raddi, Lafoensia pacari A. St.-Hil, Cecropia pachystachya Trécul. and Aegiphila sellowiana Cham.) and five non-pioneer (Myracrodruon urundeuva Allemão, Cedrela fissilis Vell., Genipa americana L., Copaifera langsdorffii Desf. and Hymenaea courbaril L.) species, in relation to the extent of lipid peroxidation in leaves. Furthermore, we examined differences between sun and shade leaves on vitamin E accumulation and the extent of lipid peroxidation. Pioneer plants showed on average 33% higher malondialdehyde levels, an indicator of lipid peroxidation, than non-pioneer species, but no significant differences in vitamin E contents. In contrast, a marked interspecific variation was observed in the levels of α-tocopherol and its precursor, γ-tocopherol. Natural variation revealed interesting relationships between vitamin E levels and the extent of lipid peroxidation in leaves. The pioneer species, P. elegans, did not accumulate α-tocopherol and displayed the highest levels of malondialdehyde. Sun and shade leaves accumulated vitamin E levels to a similar extent, except for the pioneer L. pacari and the non-pioneer C. langsdorffii, the former accumulating more α-tocopherol in sun leaves and the latter in shade leaves. We conclude that interspecific variation is higher than both leaf type and successional-group variation in terms of vitamin E accumulation and the extent of lipid peroxidation, and that vitamin E levels, particularly those of α-tocopherol, negatively correlate with the extent of lipid

  16. Intra- and intermembrane distribution of chlorin e6 derivatives

    Science.gov (United States)

    Zorin, Vladimir P.; Zorina, Tatyana E.; Mikhalovsky, Iosif S.; Khludeyev, Ivan I.

    1995-01-01

    The parameters of chlorin e6 and trimethylester of chlorin e6 incorporation and distribution in suspensions of unilamellar liposomes of DMPC, DPPC, and DSPC, as well as efficiency of the pigment redistribution from liposomes to cellular membranes have been studied. Determination of the fraction of pigments' fluorescence which is accessible to quenching by a watersoluble quencher indicates that for both chlorins the outer monolayer of the liposomal membrane is more populated than the inner one. Gel-liquid crystalline phase transition induces a shift of a part of the pigments' molecules toward the inner monolayer. By means of ultrafiltration technique it is shown that chlorins binding to liposomal membrane occurs as partitioning between water and lipid phases. The partition coefficient is affected strongly by the type of pigment, the phase state of the lipid bilayer. Similar results were obtained when the influence of the physical state of the lipid bilayer on the rate of chlorins redistribution from liposomes to cellular membrane was studied. These findings show that diffusive mobility of the sensitizer in suspensions of cellular and model membranes is a complex process which is dependent on structural features of both the pigment and its biological carriers.

  17. Chlorination of organophosphorus pesticides in natural waters.

    Science.gov (United States)

    Acero, Juan L; Benítez, F Javier; Real, Francisco J; González, Manuel

    2008-05-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 degrees C and pH 7 were determined to be 110.9, 0.004 and 191.6 M(-1) s(-1) for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L(-1) was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety.

  18. Pesticide contaminants in selected species of edible wild mushrooms from the north-eastern part of Poland.

    Science.gov (United States)

    Gałgowska, Michalina; Pietrzak-Fiećko, Renata

    2017-03-04

    The aim of this study was to determine the level of chlorinated hydrocarbon residues in selected edible mushrooms from north-eastern Poland. The experiment was carried out on 45 samples consisting of 15 fruiting bodies each of the following species: Boletus edulis, Imleria badia and Cantharellus cibarius. Dried samples were subjected to extraction of lipids with a Soxhlet and a standard procedure-based on the decomposition of lipids by concentrated sulfuric acid and the release of organic insecticides to the hexane layer-was used to determine chlorinated hydrocarbons. The quantitative determination of DDT, DDE, DDD and γ-HCH were conducted using gas chromatography with electron capture detection (GC-ECD). Chlorinated hydrocarbons were found in all tested samples. The contents of these compounds varied between all three species. Mean content of γ-HCH in B. edulis, I. badia and C. cibarius was: 2.60; 4.83; 7.52 µg kg(-1) of lipids, while the content of ΣDDT was: 57.02; 25.20; 127.10 µg kg(-1) of lipids, respectively. These results show that mushrooms from the north-eastern part of Poland can be used as potential bio-indicators of environmental contamination with chlorinated hydrocarbons. Moreover, the studied fungi could still be used as food due to the low levels of analyzed organochlorine compounds.

  19. Comparative analyses of three Chlorella species in response to light and sugar reveal distinctive lipid accumulation patterns in the Microalga C. sorokiniana.

    Science.gov (United States)

    Rosenberg, Julian N; Kobayashi, Naoko; Barnes, Austin; Noel, Eric A; Betenbaugh, Michael J; Oyler, George A

    2014-01-01

    While photosynthetic microalgae, such as Chlorella, serve as feedstocks for nutritional oils and biofuels, heterotrophic cultivation can augment growth rates, support high cell densities, and increase triacylglycerol (TAG) lipid content. However, these species differ significantly in their photoautotrophic and heterotrophic characteristics. In this study, the phylogeny of thirty Chlorella strains was determined in order to inform bioprospecting efforts and detailed physiological assessment of three species. The growth kinetics and lipid biochemistry of C. protothecoides UTEX 411, C. vulgaris UTEX 265, and C. sorokiniana UTEX 1230 were quantified during photoautotrophy in Bold's basal medium (BBM) and heterotrophy in BBM supplemented with glucose (10 g L-1). Heterotrophic growth rates of UTEX 411, 265, and 1230 were found to be 1.5-, 3.7-, and 5-fold higher than their respective autotrophic rates. With a rapid nine-hour heterotrophic doubling time, Chlorella sorokiniana UTEX 1230 maximally accumulated 39% total lipids by dry weight during heterotrophy compared to 18% autotrophically. Furthermore, the discrete fatty acid composition of each strain was examined in order to elucidate lipid accumulation patterns under the two trophic conditions. In both modes of growth, UTEX 411 and 265 produced 18:1 as the principal fatty acid while UTEX 1230 exhibited a 2.5-fold enrichment in 18:2 relative to 18:1. Although the total lipid content was highest in UTEX 411 during heterotrophy, UTEX 1230 demonstrated a two-fold increase in its heterotrophic TAG fraction at a rate of 28.9 mg L(-1) d(-1) to reach 22% of the biomass, corresponding to as much as 90% of its total lipids. Interestingly, UTEX 1230 growth was restricted during mixotrophy and its TAG production rate was suppressed to 18.2 mg L-1 d-1. This constraint on carbon flow raises intriguing questions about the impact of sugar and light on the metabolic regulation of microalgal lipid biosynthesis.

  20. Comparative analyses of three Chlorella species in response to light and sugar reveal distinctive lipid accumulation patterns in the Microalga C. sorokiniana.

    Directory of Open Access Journals (Sweden)

    Julian N Rosenberg

    Full Text Available While photosynthetic microalgae, such as Chlorella, serve as feedstocks for nutritional oils and biofuels, heterotrophic cultivation can augment growth rates, support high cell densities, and increase triacylglycerol (TAG lipid content. However, these species differ significantly in their photoautotrophic and heterotrophic characteristics. In this study, the phylogeny of thirty Chlorella strains was determined in order to inform bioprospecting efforts and detailed physiological assessment of three species. The growth kinetics and lipid biochemistry of C. protothecoides UTEX 411, C. vulgaris UTEX 265, and C. sorokiniana UTEX 1230 were quantified during photoautotrophy in Bold's basal medium (BBM and heterotrophy in BBM supplemented with glucose (10 g L-1. Heterotrophic growth rates of UTEX 411, 265, and 1230 were found to be 1.5-, 3.7-, and 5-fold higher than their respective autotrophic rates. With a rapid nine-hour heterotrophic doubling time, Chlorella sorokiniana UTEX 1230 maximally accumulated 39% total lipids by dry weight during heterotrophy compared to 18% autotrophically. Furthermore, the discrete fatty acid composition of each strain was examined in order to elucidate lipid accumulation patterns under the two trophic conditions. In both modes of growth, UTEX 411 and 265 produced 18:1 as the principal fatty acid while UTEX 1230 exhibited a 2.5-fold enrichment in 18:2 relative to 18:1. Although the total lipid content was highest in UTEX 411 during heterotrophy, UTEX 1230 demonstrated a two-fold increase in its heterotrophic TAG fraction at a rate of 28.9 mg L(-1 d(-1 to reach 22% of the biomass, corresponding to as much as 90% of its total lipids. Interestingly, UTEX 1230 growth was restricted during mixotrophy and its TAG production rate was suppressed to 18.2 mg L-1 d-1. This constraint on carbon flow raises intriguing questions about the impact of sugar and light on the metabolic regulation of microalgal lipid biosynthesis.

  1. Reactions of tetracycline antibiotics with chlorine dioxide and free chlorine.

    Science.gov (United States)

    Wang, Pei; He, Yi-Liang; Huang, Ching-Hua

    2011-02-01

    Tetracyclines (TCs) are a group of widely used antibiotics that have been frequently found in the aquatic environment. The potential reactions of TCs with common water disinfection oxidants such as chlorine dioxide (ClO(2)) and free available chlorine (FAC) have not been studied in depth and are the focus of this study. The oxidation kinetics of tetracycline, oxytetracycline, chlorotetracycline and iso-chlorotetracycline by ClO(2) and FAC are very rapid (with large apparent second-order rate constants k(app) = 2.24 × 10(5)-1.26 × 10(6) M(-1) s(-1) with ClO(2) and k(app) = 1.12 × 10(4)-1.78 × 10(6) M(-1) s(-1) with FAC at pH 7.0) and highly dependent on pH. Species-specific rate constants are obtained by kinetic modeling that incorporates pH-speciation of TCs and the oxidants (for FAC), and reveal that TCs primarily react with ClO(2) and FAC by their unprotonated dimethylamino group and deprotonated phenolic-diketone group. The modest difference in reactivity among the four TCs toward the oxidants is consistent with expectation and can be explained by structural influences on the two reactive moieties. Product evaluation shows that oxidation of TCs by ClO(2) leads to (hydr)oxylation and breakage of TC molecules, while oxidation of TCs by FAC leads to chlorinated and (hydr)oxylated products without any substantial ring breakage. Results of this study indicate that rapid transformation of TCs by oxidants such as ClO(2) and FAC under water and wastewater treatment conditions can be expected. © 2010 Elsevier Ltd. All rights reserved.

  2. Lipid and protein accumulation in developing seeds of three lupine species: Lupinus luteus L., Lupinus albus L., and Lupinus mutabilis Sweet.

    Science.gov (United States)

    Borek, Slawomir; Pukacka, Stanisława; Michalski, Krzysztof; Ratajczak, Lech

    2009-01-01

    A comparative study was carried out on the dynamics of lipid accumulation in developing seeds of three lupine species. Lupine seeds differ in lipid content; yellow lupine (Lupinus luteus L.) seeds contain about 6%, white lupine (Lupinus albus L.) 7-14%, and Andean lupine (Lupinus mutabilis Sweet) about 20% of lipids by dry mass. Cotyledons from developing seeds were isolated and cultured in vitro for 96 h on Heller medium with 60 mM sucrose (+S) or without sucrose (-S). Each medium was additionally enriched with 35 mM asparagine or 35 mM NaNO3. Asparagine caused an increase in protein accumulation and simultaneously decreased the lipid content, but nitrate increased accumulation of both protein and lipid. Experiments with [1-14C]acetate and [2-14C]acetate showed that the decrease in lipid accumulation in developing lupine seeds resulted from exhaustion of lipid precursors rather than from degradation or modification of the enzymatic apparatus. The carbon atom from the C-1 position of acetate was liberated mainly as CO2, whereas the carbon atom from the C-2 position was preferentially used in anabolic pathways. The dominant phospholipid in the investigated lupine seed storage organs was phosphatidylcholine. The main fatty acid in yellow lupine cotyledons was linoleic acid, in white lupine it was oleic acid, and in Andean lupine it was both linoleic and oleic acids. The relationship between stimulation of lipid and protein accumulation by nitrate in developing lupine cotyledons and enhanced carbon flux through glycolysis caused by the inorganic nitrogen form is discussed.

  3. Unravelling molecular mechanisms from floral initiation to lipid biosynthesis in a promising biofuel tree species, Pongamia pinnata using transcriptome analysis

    Science.gov (United States)

    Sreeharsha, Rachapudi V.; Mudalkar, Shalini; Singha, Kambam T.; Reddy, Attipalli R.

    2016-01-01

    Pongamia pinnata (L.) (Fabaceae) is a promising biofuel tree species which is underexploited in the areas of both fundamental and applied research, due to the lack of information either on transcriptome or genomic data. To investigate the possible metabolic pathways, we performed whole transcriptome analysis of Pongamia through Illumina NextSeq platform and generated 2.8 GB of paired end sequence reads. The de novo assembly of raw reads generated 40,000 contigs and 35,000 transcripts, representing leaf, flower and seed unigenes. Spatial and temporal expression profiles of photoperiod and floral homeotic genes in Pongamia, identified GIGANTEA (GI) - CONSTANS (CO) - FLOWERING LOCUS T (FT) as active signal cascade for floral initiation. Four prominent stages of seed development were selected in a high yielding Pongamia accession (TOIL 1) to follow the temporal expression patterns of key fatty acid biosynthetic genes involved in lipid biosynthesis and accumulation. Our results provide insights into an array of molecular events from flowering to seed maturity in Pongamia which will provide substantial basis for modulation of fatty acid composition and enhancing oil yields which should serve as a potential feedstock for biofuel production. PMID:27677333

  4. Reactive oxygen species facilitate translocation of hormone sensitive lipase to the lipid droplet during lipolysis in human differentiated adipocytes.

    Directory of Open Access Journals (Sweden)

    Sarah A Krawczyk

    Full Text Available In obesity, there is an increase in reactive oxygen species (ROS within adipose tissue caused by increases in inflammation and overnutrition. Hormone sensitive lipase (HSL is part of the canonical lipolytic pathway and critical for complete lipolysis. This study hypothesizes that ROS is a signal that integrates regulation of lipolysis by targeting HSL. Experiments were performed with human differentiated adipocytes from the subcutaneous depot. Antioxidants were employed as a tool to decrease ROS, and it was found that scavenging ROS with diphenyliodonium, N-acetyl cysteine, or resveratrol decreased lipolysis in adipocytes. HSL phosphorylation of a key serine residue, Ser552, as well as translocation of this enzyme from the cytosol to the lipid droplet upon lipolytic stimulation were both abrogated by scavenging ROS. The phosphorylation status of other serine residues on HSL were not affected. These findings are significant because they document that ROS contributes to the physiological regulation of lipolysis via an effect on translocation. Such regulation could be useful in developing new obesity therapies.

  5. Reactive oxygen species facilitate translocation of hormone sensitive lipase to the lipid droplet during lipolysis in human differentiated adipocytes.

    Science.gov (United States)

    Krawczyk, Sarah A; Haller, Jorge F; Ferrante, Tom; Zoeller, Raphael A; Corkey, Barbara E

    2012-01-01

    In obesity, there is an increase in reactive oxygen species (ROS) within adipose tissue caused by increases in inflammation and overnutrition. Hormone sensitive lipase (HSL) is part of the canonical lipolytic pathway and critical for complete lipolysis. This study hypothesizes that ROS is a signal that integrates regulation of lipolysis by targeting HSL. Experiments were performed with human differentiated adipocytes from the subcutaneous depot. Antioxidants were employed as a tool to decrease ROS, and it was found that scavenging ROS with diphenyliodonium, N-acetyl cysteine, or resveratrol decreased lipolysis in adipocytes. HSL phosphorylation of a key serine residue, Ser552, as well as translocation of this enzyme from the cytosol to the lipid droplet upon lipolytic stimulation were both abrogated by scavenging ROS. The phosphorylation status of other serine residues on HSL were not affected. These findings are significant because they document that ROS contributes to the physiological regulation of lipolysis via an effect on translocation. Such regulation could be useful in developing new obesity therapies.

  6. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    OpenAIRE

    Taylor, Robert H; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains wer...

  7. Differences between Lipids Extracted from Five Species Are Not Sufficient To Explain Biomagnification of Nonpolar Organic Chemicals

    DEFF Research Database (Denmark)

    Jahnke, Annika; Holmbäck, Jan; Andersson, Rina Argelia

    2015-01-01

    headspace from spiked olive oil to determine their sorptive capacities. Lipids from seal blubber and pork bacon solely composed of triglycerides had capacities similar to that of olive oil; lipids from mussels, herring, and guillemot egg had quantifiable fractions of phospholipids and cholesterol and showed...... capacities reduced by factors of up to 2.3-fold. Generally, the sorptive capacities of the lipids were not elevated relative to the olive oil controls and are unlikely to explain a substantial part of biomagnification....

  8. Bioaccumulation factors for chlorinated benzenes, chlorinated butadienes and hexachloroethane

    Energy Technology Data Exchange (ETDEWEB)

    Burkhard, L.P. [Environmental Protection Agency, Duluth, MN (United States). National Health and Environmental Effects Research Lab.; Sheedy, B.R. [AScI Corp., Duluth, MN (United States); McCauley, D.J.; DeGraeve, G.M. [Battelle-Great Lakes Environmental Center, Traverse City, MI (United States)

    1997-08-01

    A field study was performed that measured bioaccumulation factors (BAFs) for chlorinated benzenes, chlorinated butadienes, and hexachloroethane in four species, Fundulus heteroclitus (mummichog), Callinectes sapidus (blue crabs), Brevoortia patronus (gulf menhaden), and Micropoganias undulatus (Atlantic croaker). The measured BAFs were not significantly different among the fishes. The measured BAFs for the C. sapidus were in good agreement with those measured for the fishes except for hexachloroethane (HCE), E- and Z-1,1,2,3,4-pentachlorobuta-1,3-diene (E-and Z-PeCBD), and hexachlorobuta-1,3-diene (HCBD). Their measured BAFs were approximately an order of magnitude smaller than those measured for the fishes. The measured BAFs were also in good agreement with BAFs reported/derived from the literature and to BAFs predicted using two methods of the Environmental Protection Agency (EPA) except for HCE, E- and Z-PeCBD, and HCBD in the C. sapidus. These BAFs were much smaller than the reported/derived and predicted BAFs. The smaller BAFs for HCE, E- and Z-PeCBD, and HCBD were consistent with the metabolism abilities for the C. sapidus, and metabolism processes are believed to be the cause for the smaller BAFs. The predicted BAFs were within a factor of five of the measured BAFs for 90% (n = 48) and 94% (n = 32) using the two methods of the EPA.

  9. Development of a Site-Specific Kinetic Model for Chlorine Decay and the Formation of Chlorination By-Products in Seawater

    Directory of Open Access Journals (Sweden)

    Suhur Saeed

    2015-07-01

    Full Text Available Chlorine is used commonly to prevent biofouling in cooling water systems. The addition of chlorine poses environmental risks in natural systems due to its tendency to form chlorination by-products (CBPs when exposed to naturally-occurring organic matter (NOM. Some of these CBPs can pose toxic risks to aquatic and benthic species in the receiving waters. It is, therefore, important to study the fate of residual chlorine and CBPs to fully understand the potential impacts of chlorination to the environment. The goal of this study was to develop improved predictions of how chlorine and CBP concentrations in seawater vary with time, chlorine dose and temperature. In the present study, chlorination of once-through cooling water at Ras Laffan Industrial City (RLIC, Qatar, was studied by collecting unchlorinated seawater from the RLIC cooling water system intake, treating it with chlorine and measuring time series of chlorine and CBP concentrations. Multiple-rate exponential curves were used to represent fast and slow chlorine decay and CBP formation, and site-specific chlorine kinetic relationships were developed. Through extensive analysis of laboratory measurements, it was found that only some of the control parameters identified in the literature were important for predicting residual chlorine and CBP concentrations for this specific location. The new kinetic relationships were able to significantly improve the predictability and validity of Generalized Environmental Modeling System for Surfacewaters (GEMSS-chlorine kinetics module (CKM, a three-dimensional hydrodynamic and chlorine kinetics and transport model when applied for RLIC outfall studies using actual field measurements.

  10. A comparison of iodinated trihalomethane formation from chlorine, chlorine dioxide and potassium permanganate oxidation processes.

    Science.gov (United States)

    Zhang, Tian-Yang; Xu, Bin; Hu, Chen-Yan; Lin, Yi-Li; Lin, Lin; Ye, Tao; Tian, Fu-Xiang

    2015-01-01

    This study compared the formation of iodinated trihalomethanes (I-THMs) from iodide-containing raw waters oxidized by chlorine, chlorine dioxide (ClO₂) and potassium permanganate (KMnO₄) at different oxidant concentrations, reaction times, pHs, initial iodide concentrations and bromide to iodide mass ratios. Among the six investigated I-THMs, iodoform was the major species formed during the oxidation using chlorine, ClO₂ and KMnO₄. When oxidant concentration increased from 0.1 to 3.0 mg/L, the formation of I-THMs increased and then decreased for chlorine and ClO₂, but kept increasing for KMnO₄. As the reaction time went by, I-THM concentration increased to a plateau within 10 h (ClO₂ within only 1 h, especially) for all the three oxidants. I-THM formation gradually increased from pH 3.0 to 9.0 and remained stable at pH values higher than 7.5 for chlorine; however, for ClO₂ and KMnO₄ the highest I-THM formation showed at pH 7.0 and 7.5, respectively. As initial iodide concentration increased from 20 to 800 μg/L, the total amount and species of I-THMs increased for the three oxidants. Iodide contributed to I-THM formation much more significantly than bromide.

  11. 藻有机物在含溴离子条件下氯化消毒HAAs的生成种类%Haloacetic acids species from the chlorination of algal organic matter in the presence of bromide

    Institute of Scientific and Technical Information of China (English)

    魏源源; 刘燕; 刘翔; 代瑞华

    2011-01-01

    藻类污染和溴离子存在是影响沿海地区水库水源消毒副产物形成的重要因素。在和无溴离子存在条件下,以藻细胞模拟生化成分(BSA、鱼油和淀粉),铜绿微囊藻细胞及其胞外有机物为前躯物进行氯化消毒对比实验,从藻细胞生化成分的角度探究藻有机物作为消毒副产物前躯物时,且水中存在溴离子的条件下,氯化消毒形成卤乙酸(HAAs)的种类情况。结果表明,3种模拟生化成分在溴离子存在条件下,形成的溴代HAAs仅为溴氯乙酸或二溴乙酸的1种或2种。与BSA和淀粉为前躯物时形成溴代HAAs的产物种类相比,溴离子对鱼油为前躯物时形成溴代HAAs产物种类的影响更大。模拟生化成分预测NHaAs副产物种类与具体藻种形成的HAAs副产物种类之间具有较好的吻合度。%Bromide and algal pollution are important factors influencing disinfection byproducts (DBPs) formation and speciation in reservoir water in coastal areas. The chlorination of model algal cellular compounds (bovine serum albumin, fish oil and starch), Microcystis aeruginosa and its extra-cellular organic matters (EOMs) were conducted in the absence and presence of bromide. The main aim of the present study is to explore their potential as precursors for haloacetic acids (HAAs) speciation upon chlorination in the presence of bromide. The results showed that bromochloroacetic acid (BCAA) or/and dibromoacetic acid (DBAA) was/were produced as for brominated HAAs (Br-HAAs) from the three model compounds in the presence of bromide. The effect of bromide on Br-HAAs speciation upon fish oil chlorination was more evident than with BSA and starch. There was a good correlation between the species predicted from the model compounds and those obtained from specific algal species.

  12. Fatty acids modulate Toll-like receptor 4 activation through regulation of receptor dimerization and recruitment into lipid rafts in a reactive oxygen species-dependent manner.

    Science.gov (United States)

    Wong, Scott W; Kwon, Myung-Ja; Choi, Augustine M K; Kim, Hong-Pyo; Nakahira, Kiichi; Hwang, Daniel H

    2009-10-02

    The saturated fatty acids acylated on Lipid A of lipopolysaccharide (LPS) or bacterial lipoproteins play critical roles in ligand recognition and receptor activation for Toll-like Receptor 4 (TLR4) and TLR2. The results from our previous studies demonstrated that saturated and polyunsaturated fatty acids reciprocally modulate the activation of TLR4. However, the underlying mechanism has not been understood. Here, we report for the first time that the saturated fatty acid lauric acid induced dimerization and recruitment of TLR4 into lipid rafts, however, dimerization was not observed in non-lipid raft fractions. Similarly, LPS and lauric acid enhanced the association of TLR4 with MD-2 and downstream adaptor molecules, TRIF and MyD88, into lipid rafts leading to the activation of downstream signaling pathways and target gene expression. However, docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid, inhibited LPS- or lauric acid-induced dimerization and recruitment of TLR4 into lipid raft fractions. Together, these results demonstrate that lauric acid and DHA reciprocally modulate TLR4 activation by regulation of the dimerization and recruitment of TLR4 into lipid rafts. In addition, we showed that TLR4 recruitment to lipid rafts and dimerization were coupled events mediated at least in part by NADPH oxidase-dependent reactive oxygen species generation. These results provide a new insight in understanding the mechanism by which fatty acids differentially modulate TLR4-mediated signaling pathway and consequent inflammatory responses which are implicated in the development and progression of many chronic diseases.

  13. A study of lipid- and water-soluble arsenic species in liver of Northeast Arctic cod (Gadus morhua) containing high levels of total arsenic

    DEFF Research Database (Denmark)

    Sele, Veronika; Sloth, Jens Jørgen; Julshamn, Kale;

    2015-01-01

    In the present study liver samples (n = 26) of Northeast Arctic cod (Gadus morhua), ranging in total arsenic concentrations from 2.1 to 240 mg/kg liver wet weight (ww), were analysed for their content of total arsenic and arsenic species in the lipid-soluble and water-soluble fractions. The arsenic...... concentrations in the lipid fractions ranged from 1.8 to 16.4 mg As/kg oil of liver, and a linear correlation (r(2) = 0.80, p arsenic concentrations in liver and the total arsenic concentrations in the respective lipid fractions of the same livers. The relative proportion...... of arsenolipids was considerably lower in liver samples with high total arsenic levels (33-240 mg/kg ww), which contained from 3 to 7% of the total arsenic in the lipid-soluble fraction. In contrast liver samples with low arsenic concentrations (2.1-33 mg/kg ww) contained up to 50% of the total arsenic as lipid...

  14. Chlorine dioxide and hemodialysis

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.P. (Dartmouth Coll., Hanover, NH (USA). Dept. of Pharmacology and Toxicology)

    1989-05-01

    Because it has little or no tendency to generate carcinogenic trihalomethanes such as chloroform, chlorine dioxide is an attractive alternative to chlorine for drinking water disinfection. There are, however, concerns about its acute toxicity, and the toxic effects of its by-products, chlorite and chlorate. The human experience with chlorine dioxide in both controlled, prospective studies and in actual use situations in community water supplies have as yet failed to reveal adverse health effects. The EPA has recommended standards of 0.06 mg/L for chlorine dioxide and standards of 0.007 mg/L for chlorite and chlorate in drinking water. Among groups who may be at special risk from oxychlorines in drinking water are patients who must undergro chronic extracorporeal hemodialysis. Although even units for home hemodialysis are supposed to be equipped with devices which effectively remove oxychlorines, there is a always a possibility of operator error or equipment failure. When the equipment is adequately maintained, it is likely that dialysis patients will have more intensive exposures from drinking water than from dialysis fluids despite the much larger volumes of water that are involved in dialysis. This paper discusses a hemodialysis and the standards and effects of oxychlorines. 90 refs., 2 tabs.

  15. Evaluation of the simultaneous production of lutein and lipids using a vertical alveolar panel bioreactor for three Chlorella species 

    OpenAIRE

    2014-01-01

    The concept of a biorefinery improves the economic efficiency of a biofuel production process from microalgae by recovering high value added compounds. Lutein is a carotenoid currently extracted from petals of Tagetes erecta with an established market in poultry and in human nutritional supplements. For the very first time, an extended study on the lipid and lutein production over three Chlorella species as well as cell disruption methods was performed. Chlorella vulgaris, Chlorella zofingien...

  16. Responses of plant biomass, photosynthesis and lipid peroxidation to warming and precipitation change in two dominant species (Stipa grandis and Leymus chinensis) from North China Grasslands

    OpenAIRE

    Song, Xiliang; Wang, Yuhui; Lv, Xiaomin

    2016-01-01

    Abstract Influential factors of global change affect plant carbon uptake and biomass simultaneously. Although the effects from warming and precipitation change have been extensive studied separately, the responses of plant biomass, photosynthesis, and lipid peroxidation to the interaction of these factors are still not fully understood. In this study, we examined the physiological responses of two dominant plant species from grasslands of northern China with different functional traits to com...

  17. Silver-Catalyzed C(sp(3))-H Chlorination.

    Science.gov (United States)

    Ozawa, Jun; Kanai, Motomu

    2017-03-17

    A silver-catalyzed chlorination of benzylic, tertiary, and secondary C(sp(3))-H bonds was developed. The reaction proceeded with as low as 0.2 mol % catalyst loading at room temperature under air atmosphere with synthetically useful functional group compatibility. The regioselectivity and reactivity tendencies suggest that the chlorination proceeded through a radical pathway, but an intermediate alkylsilver species cannot be ruled out.

  18. Bromoform production in tropical open-ocean waters: OTEC chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Hartwig, E.O.; Valentine, R.

    1981-09-01

    The bromoform, and other volatile organics produced while chlorinating both the evaporator and condenser seawater during operation of the one megawatt (1 MW) OTEC-1 test facility are reported. Although many halogenated compounds might be produced as a result of chlorination, the quantitative analyses in this study focused on volatile EPA priority pollutants. Bromoform is the compound specifically recognized as a potential pollutant. Its concentration may be indicative of other halogenated species.

  19. Synthesis and phototoxicity of isomeric 7,9-diglutathione pyrrole adducts: Formation of reactive oxygen species and induction of lipid peroxidation

    Directory of Open Access Journals (Sweden)

    Liang Ma

    2015-09-01

    peroxidation is mediated by reactive oxygen species (ROS. These results suggest that 7,9-diGS-DHPs are phototoxic, generating lipid peroxidation mediated by ROS.

  20. Reversed flow injection spectrophotometric determination of low residuals of chlorine dioxide in water using chlorophenol red

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel,simple,rapid,sensitive and highly selective flow injection procedure for the spectrophotometrie determination of chlorine dioxide in the presence of other chlorine species,viz,free chlorine,chlorite,chlorate and hypoehlorite,is developed.The method is based on the discoloration reaction between chlorine dioxide and chlorophenol red and can overcome the shortcomings existed in direct speetrophotometrie determination for chlorine dioxide owing to the serious interference of free and combined chlorine.The procedure gave a linear calibration graph over the range 0-0.71 mg/L of chlorine dioxide.With a detection limit of 0.024 mg/L and a sample throughput of 60 samples/h.

  1. Lipids and lipid binding proteins: a perfect match.

    Science.gov (United States)

    Glatz, Jan F C

    2015-02-01

    Lipids serve a great variety of functions, ranging from structural components of biological membranes to signaling molecules affecting various cellular functions. Several of these functions are related to the unique physico-chemical properties shared by all lipid species, i.e., their hydrophobicity. The latter, however, is accompanied by a poor solubility in an aqueous environment and thus a severe limitation in the transport of lipids in aqueous compartments such as blood plasma and the cellular soluble cytoplasm. Specific proteins which can reversibly and non-covalently associate with lipids, designated as lipid binding proteins or lipid chaperones, greatly enhance the aqueous solubility of lipids and facilitate their transport between tissues and within tissue cells. Importantly, transport of lipids across biological membranes also is facilitated by specific (membrane-associated) lipid binding proteins. Together, these lipid binding proteins determine the bio-availability of their ligands, and thereby markedly influence the subsequent processing, utilization, or signaling effect of lipids. The bio-availability of specific lipid species thus is governed by the presence of specific lipid binding proteins, the affinity of these proteins for distinct lipid species, and the presence of competing ligands (including pharmaceutical compounds). Recent studies suggest that post-translational modifications of lipid binding proteins may have great impact on lipid-protein interactions. As a result, several levels of regulation exist that together determine the bio-availability of lipid species. This short review discusses the significance of lipid binding proteins and their potential application as targets for therapeutic intervention.

  2. Temporal evolution of chlorine and related species observed with ground-based FTIR at Syowa Station, Antarctica during late winter and spring in 2007 and 2011

    Science.gov (United States)

    Nakajima, Hideaki; Saeki, Kosuke; Murata, Isao; Nagahama, Yoshihiro; Takeda, Masanori

    2017-04-01

    Vertical profiles of O3, HNO3, and HCl and vertical column of ClONO2 were retrieved from solar spectra taken with a ground-based Fourier-Transform infrared spectrometer (FTIR) installed at Syowa Station, Antarctica (69.0S, 39.6E) from March to December, 2007 and September to November, 2011. We analyzed temporal variation of these species combined with ClO data taken by Aura/MLS (Microwave Limb Sounder) satellite sensor at 18 and 22 km over Syowa Station. In early July, polar stratospheric clouds (PSCs) started to be formed over Syowa Station. With the return of sunlight at Syowa Station in early July, ClONO2 and HCl showed depleted values while ClO showed enhanced values. At two altitudes (18 and 22 km), when ClO concentrations started to decline in early September, HCl started to increase rapidly, while the increase in ClONO2 was gradual. The Cly partitioning between HCl, ClONO2, and ClO showed difference at different altitudes. At the altitudes of 18 km, where ozone was almost depleted, ClO and HNO3 amounts are low, so conversion to HCl was favored rather than ClONO2. Whereas, at 22 km, sufficient ozone still remained, at an amount that ClONO2 formation from ClO and NOy species continued to occur at this altitude.

  3. Pycnogenol® inhibits lipid accumulation in 3T3-L1 adipocytes with the modulation of reactive oxygen species (ROS) production associated with antioxidant enzyme responses.

    Science.gov (United States)

    Lee, Ok-Hwan; Seo, Min-Jung; Choi, Hyeon-Son; Lee, Boo-Yong

    2012-03-01

    Pycnogenol® is a group of flavonoids with antioxidant effects. Adipogenesis is the process of adipocyte differentiation. It causes the increase of lipids as well as ROS (reactive oxygen species). Lipid accumulation and ROS production were determined in 3 T3-L1 adipocyte, and the effect of Pycnogenol® was evaluated. Lipid accumulation was elevated in adipocyte treated with hydrogen peroxide, one of the ROS. Pycnogenol® showed an inhibitory effect on the lipid accumulation and ROS production during the adipogenesis. We also investigated the molecular events associated with ROS production and lipid accumulation. Our results showed that Pycnogenol® inhibited the mRNA expression of pro-oxidant enzymes, such as NOX4 (NADPH (nicotinamide adenine dinucleotide phosphate hydrogen) oxidase 4), and the NADPH-producing G6PDH (glucose-6-phosphate dehydrogenase) enzyme. In addition, Pycnogenol® suppressed the mRNA abundance of adipogenic transcription factors, PPAR-γ (peroxisome proliferator-activated receptor γ) and C/EBP-α (CCAAT/enhancer binding protein α), and their target gene, aP2 (adipocyte protein 2) responsible for fatty acid transportation. On the other hand, Pycnogenol® increased the abundance of antioxidant proteins such as Cu/Zn-SOD (copper-zinc superoxide dismutase), Mn-SOD (manganese superoxide dismutase), GPx (glutathione peroxidase) and GR (glutathione reductase). Our results suggest that Pycnogenol® inhibits lipid accumulation and ROS production by regulating adipogenic gene expression and pro-/antioxidant enzyme responses in adipocytes.

  4. REVIEWING AND IDENTIFYING AMINO ACIDS OF HUMAN, MURINE, CANINE AND EQUINE TLR4 / MD-2 RECEPTOR COMPLEXES CONFERRING ENDOTOXIC INNATE IMMUNITY ACTIVATION BY LPS/LIPID A, OR ANTAGONISTIC EFFECTS BY ERITORAN, IN CONTRAST TO SPECIES-DEPENDENT MODULATION BY LIPID IVA

    Directory of Open Access Journals (Sweden)

    Thomas Scior

    2013-02-01

    Full Text Available There is literature evidence gathered throughout the last two decades reflecting unexpected species differences concerning the immune response to lipid IVa which provides the opportunity to gain more detailed insight by the molecular modeling approach described in this study. Lipid IVa is a tetra-acylated precursor of lipid A in the biosynthesis of lipopolysaccharide (LPS in Gram-negative bacteria. Lipid A of the prototypic E. coli-type is a hexa-acylated structure that acts as an agonist in all tested mammalian species by innate immunorecognition via the Toll-like receptor 4 (TLR4/myeloid differentiation factor 2 (MD-2 receptor complex. In contrast, lipid IVa is proinflammatory in mouse cells (agonism but it remains inactive to human macrophages and even antagonizes the action of potent agonists like E. coli-type lipid A. This particular ambivalent activity profile of lipid IVa has been confirmed in other mammalian species: in equine cells Lipid IVa also acts in a weak agonistic manner, whereas being inactive and antagonizing the lipid A-induced activation of canine TLR4/MD-2. Intriguingly, the respective TLR4 amino acid sequences of the latter species are more identical to the human (67%, 68% than to the murine (62%, 58% ortholog. In order to address the unpaired activity-sequence dualism for human, murine, canine and equine species regarding the activity of lipid IVa as compared to LPS and lipid A and, we review the literature and computationally pinpoint the differential biological effects of lipid IVa versus LPS and lipid A to specific amino acid residues. In contrast to lipid IVa the structurally related synthetic compound Eritoran (E5564 acts consistently in an antagonistic manner in these mammalian species and serves as a reference ligand for molecular modeling in this study. The combined evaluation of data sets provided by prior studies and in silico homology mapping of differential residues of TLR4/MD-2 complexes lends detailed insight

  5. Reviewing and identifying amino acids of human, murine, canine and equine TLR4 / MD-2 receptor complexes conferring endotoxic innate immunity activation by LPS/lipid A, or antagonistic effects by Eritoran, in contrast to species-dependent modulation by lipid IVa

    Directory of Open Access Journals (Sweden)

    Christian Alexander

    2013-02-01

    Full Text Available There is literature evidence gathered throughout the last two decades reflecting unexpected species differences concerning the immune response to lipid IVa which provides the opportunity to gain more detailed insight by the molecular modeling approach described in this study. Lipid IVa is a tetra-acylated precursor of lipid A in the biosynthesis of lipopolysaccharide (LPS in Gram-negative bacteria. Lipid A of the prototypic E. coli-type is a hexa-acylated structure that acts as an agonist in all tested mammalian species by innate immunorecognition via the Toll-like receptor 4 (TLR4/myeloid differentiation factor 2 (MD-2 receptor complex. In contrast, lipid IVa is proinflammatory in mouse cells (agonism but it remains inactive to human macrophages and even antagonizes the action of potent agonists like E. coli -type lipid A. This particular ambivalent activity profile of lipid IVa has been confirmed in other mammalian species: in equine cells Lipid IVa also acts in a weak agonistic manner, whereas being inactive and antagonizing the lipid A-induced activation of canine TLR4/MD-2. Intriguingly, the respective TLR4 amino acid sequences of the latter species are more identical to the human (67%, 68% than to the murine (62%, 58% ortholog. In order to address the unpaired activity-sequence dualism for human, murine, canine and equine species regarding the activity of lipid IVa as compared to LPS and lipid A and, we review the literature and computationally pinpoint the differential biological effects of lipid IVa versus LPS and lipid A to specific amino acid residues. In contrast to lipid IVa the structurally related synthetic compound Eritoran (E5564 acts consistently in an antagonistic manner in these mammalian species and serves as a reference ligand for molecular modeling in this study. The combined evaluation of data sets provided by prior studies and in silico homology mapping of differential residues of TLR4/MD-2 complexes lends detailed

  6. Reviewing and identifying amino acids of human, murine, canine and equine TLR4 / MD-2 receptor complexes conferring endotoxic innate immunity activation by LPS/lipid A, or antagonistic effects by Eritoran, in contrast to species-dependent modulation by lipid IVa.

    Science.gov (United States)

    Scior, Thomas; Alexander, Christian; Zaehringer, Ulrich

    2013-01-01

    There is literature evidence gathered throughout the last two decades reflecting unexpected species differences concerning the immune response to lipid IVa which provides the opportunity to gain more detailed insight by the molecular modeling approach described in this study. Lipid IVa is a tetra-acylated precursor of lipid A in the biosynthesis of lipopolysaccharide (LPS) in Gram-negative bacteria. Lipid A of the prototypic E. coli-type is a hexa-acylated structure that acts as an agonist in all tested mammalian species by innate immunorecognition via the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD-2) receptor complex. In contrast, lipid IVa is proinflammatory in mouse cells (agonism) but it remains inactive to human macrophages and even antagonizes the action of potent agonists like E. coli-type lipid A. This particular ambivalent activity profile of lipid IVa has been confirmed in other mammalian species: in equine cells Lipid IVa also acts in a weak agonistic manner, whereas being inactive and antagonizing the lipid A-induced activation of canine TLR4/MD-2. Intriguingly, the respective TLR4 amino acid sequences of the latter species are more identical to the human (67%, 68%) than to the murine (62%, 58%) ortholog. In order to address the unpaired activity-sequence dualism for human, murine, canine and equine species regarding the activity of lipid IVa as compared to LPS and lipid A and, we review the literature and computationally pinpoint the differential biological effects of lipid IVa versus LPS and lipid A to specific amino acid residues. In contrast to lipid IVa the structurally related synthetic compound Eritoran (E5564) acts consistently in an antagonistic manner in these mammalian species and serves as a reference ligand for molecular modeling in this study. The combined evaluation of data sets provided by prior studies and in silico homology mapping of differential residues of TLR4/MD-2 complexes lends detailed insight into the

  7. Gelidium elegans, an edible red seaweed, and hesperidin inhibit lipid accumulation and production of reactive oxygen species and reactive nitrogen species in 3T3-L1 and RAW264.7 cells.

    Science.gov (United States)

    Jeon, Hui-Jeon; Seo, Min-Jung; Choi, Hyeon-Son; Lee, Ok-Hwan; Lee, Boo-Yong

    2014-11-01

    Gelidium elegans is an edible red alga native to the intertidal area of northeastern Asia. We investigated the effect of G. elegans extract and its main flavonoids, rutin and hesperidin, on lipid accumulation and the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in 3T3-L1 and RAW264.7 cells. Our data show that G. elegans extract decreased lipid accumulation and ROS/RNS production in a dose-dependent manner. The extract also inhibited the mRNA expression of adipogenic transcription factors, such as peroxisome proliferator-activated receptor gamma and CCAAT/enhancer-binding protein alpha, while enhancing the protein expression of the antioxidant enzymes superoxide dismutases 1 and 2, glutathione peroxidase, and glutathione reductase compared with controls. In addition, lipopolysaccharide-induced nitric oxide production was significantly reduced in G. elegans extract-treated RAW264.7 cells. In analysis of the effects of G. elegans flavonoids on lipid accumulation and ROS/RNS production, only hesperidin showed an inhibitory effect on lipid accumulation and ROS production; rutin did not affect adipogenesis and ROS status. The antiadipogenic effect of hesperidin was evidenced by the downregulation of peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha, and fatty acid binding protein 4 gene expression. Collectively, our data suggest that G. elegans is a potential food source containing antiobesity and antioxidant constituents.

  8. Fatty acid composition and Ω3/Ω6 ratios of the muscle lipids of six fish species in Sugla Lake, Turkey

    Directory of Open Access Journals (Sweden)

    Cakmak Selim Yavuz

    2012-01-01

    Full Text Available Fatty acid composition of the muscle lipids of Carassius gibelio, Pseudophoxinus anatolicus, Sander lucioperca, Tinca tinca, Vimba vimba tenella and Capoeta capoeta in Sugla Lake were determined. In all species, palmitic acid (13.25- 18.54% of total fatty acids and oleic acid (11.93-34.23% of total fatty acids were identified as major saturated fatty acid (SFA and monounsaturated fatty acid (MUFA, respectively. Docosahexaenoic acid (DHA was found to be the major polyunsaturated fatty acid (PUFA in T. tinca, C. capoeta, C. gibelio, P. anatolicus and S. lucioperca while the predominant PUFA of V. vimba tenella was eicosapentaenoic acid (EPA. S. lucioperca contained more ω3 fatty acids than the other fish species. The percentages of total ω3 fatty acids were higher than those of total ω6 fatty acids in all species. Since P. anatolicus is endemic and endangered, this species should be protected and produced for future marketing.

  9. 氯分种类对垃圾焚烧过程重金属迁移特性的影响%Effect of chlorine species on transfer characteristics of heavy metals during municipal solid waste incineration

    Institute of Scientific and Technical Information of China (English)

    曹晓非; 徐觉慧; 李和平; 刘静

    2014-01-01

    在管式反应炉上,通过加入有机氯(PVC)和无机氯(NaCl)研究了垃圾焚烧时氯对重金属迁移特性的影响。结果表明,氯分在低温下对重金属挥发几乎没有影响,只有在较高的焚烧温度下氯分才对重金属的挥发特性产生影响,且垃圾焚烧过程中氯分存在使重金属更易向飞灰或烟气中迁移,垃圾中有机氯对重金属迁移特性的影响要大于无机氯。氯的存在会显著改变分布在飞灰和烟气或底渣和飞灰间的重金属的分布特性。%Effects of chlorine on heavy metals distribution at different temperatures are studied with mixed wastes incinerated in a quartz tube by adding organic chlorine(PVC) and inorganic chlorine (NaCl).The results indicate that the chlorine content in wastes has no influences on heavy metals distribution at lower temperature.Only at higher temperature the influences can be detected.When chlorine is contained in wastes incineration,heavy metals will transfer to fly ash or flue gas more easily.The organic chlorine has more impacts on heavy metals transfer characteristics than inorganic chlorine.The chlorine can obviously alter distribution characteristics of the heavy metals that disperse between fly ash and flue gas or between bottom ash and fly ash.

  10. [Comparison of the quality and toxicity of wastewater after chlorine and chlorine dioxide disinfections].

    Science.gov (United States)

    Wang, Li-sha; Zhang, Tong; Hu, Hong-ying

    2005-11-01

    The effects of chlorine and chlorine dioxide disinfections on quality and toxicity of wastewater were compared. The experiment results showed that chlorine disinfection had no obvious effect on wastewater color, while chlorine dioxide disinfection decreased wastewater color observably. The DOC of wastewater did not change much after chlorine and chlorine dioxide disinfections. Chlorine disinfection significantly increased UV230 of wastewater and chlorine dioxide disinfection slightly decreased UV230 of wastewater. When the disinfectants dosage was 30 mg/L, UV230 increased about 0.7 cm(-1) after chlorine disinfection and decreased about 0.05 cm(-1) after chlorine dioxide disinfection. The acute toxicity of wastewater increased with increasing disinfectants dosage for both chlorine and chlorine dioxide disinfections and the acute toxicity after chlorine disinfection is much stronger than that after chlorine dioxide disinfection. The genotoxicity of wastewater increased slightly after chlorine disinfection and decreased slightly after chlorine dioxide disinfection.

  11. Effects of plant species, stage of maturity, and level of formic acid addition on lipolysis, lipid content, and fatty acid composition during ensiling.

    Science.gov (United States)

    Koivunen, E; Jaakkola, S; Heikkilä, T; Lampi, A-M; Halmemies-Beauchet-Filleau, A; Lee, M R F; Winters, A L; Shingfield, K J; Vanhatalo, A

    2015-09-01

    Forage type and management influences the nutritional quality and fatty acid composition of ruminant milk. Replacing grass silage with red clover (RC; L.) silage increases milk fat 18:3-3 concentration. Red clover has a higher polyphenol oxidase (PPO) activity compared with grasses, which has been suggested to decrease lipolysis and . The present study characterized the abundance and fatty acid composition of esterified lipid and NEFA before and after ensiling of grass and RC to investigate the influence of forage species, growth stage, and extent of fermentation on lipolysis. A randomized block design with a 2 × 3 × 4 factorial arrangement of treatments was used. Treatments comprised RC or a mixture of timothy ( L.) and meadow fescue ( Huds.) harvested at 3 growth stages and treated with 4 levels of formic acid (0, 2, 4, and 6 L/t). Lipid in silages treated with 0 or 6 L/t formic acid were extracted and separated into 4 fractions by TLC. Total PPO activity in fresh herbage and the content of soluble bound phenols in all silages were determined. Concentrations of 18:3-3 and total fatty acids (TFA) were higher ( ensilage of RC decreases lipolysis . For both plant species, total PPO activity was not associated with the extent of lipolysis . However, bound phenols formed via PPO activity appear to have a role in protecting lipid and protein against degradation in grass and lowering proteolysis of RC during ensiling.

  12. Reactions of aqueous chlorine and chlorine dioxide with model food compounds.

    OpenAIRE

    Fukayama, M Y; Tan, H; Wheeler, W B; Wei, C I

    1986-01-01

    Chlorine and chlorine dioxide (ClO2), common disinfecting and bleaching chemicals used in the food industry, are potent oxidizing and chlorinating agents. Unfortunately, little is known about the nature of the reactions of chlorine with organic food constituents. This presentation reviews published information concerning the reactions of chlorine gas (Cl2[g]), aqueous chlorine, and ClO2 with model food compounds, the fate of chlorine during the chlorination of specific food products, and the ...

  13. Effect of chlorine and fluorine elements on mercury species and its distribution in flue gas%氯、氟离子对烟气中汞形态和分布的影响

    Institute of Scientific and Technical Information of China (English)

    殷立宝; 余亮英; 徐齐胜; 熊扬恒

    2014-01-01

    在100 kPa、50~950℃的条件下,采用化学热力平衡分析方法研究了煤燃烧过程中 F 离子和Cl 离子对痕量元素汞的形态及其分布的影响。结果表明:在煤燃烧的较高温度区域,单质汞是汞的主要形式;随着烟气温度的降低,单质汞将发生化学反应生成二价汞的化合物,形式主要为 HgCl2(g);氯离子含量的增加可以增强汞的蒸发,有利于排放控制,而氟元素对汞在烟气中的行为特性几乎无影响。%The effect of F- and Cl- formed during coal combustion on mercury species and its distribution at 100 kPa and 50 ℃ to 950 ℃ was investigated by using the chemical thermodynamic equilibrium method. The results indicate that elemental mercury is the main form in the maximum temperature zone of coal combustion.With the reduction of temperature,the elemental mercury will convert into bivalent mercury compound,which is mainly HgCl2 (g),through chemical reaction.In addition,the increase of chlorine ele-ment can lead to acceleration in mercury evaporation.However,the fluorine element nearly has no influence on mercury's behavior in the flue gas.

  14. Electrochemical decomposition of chlorinated hydrocarbons

    OpenAIRE

    McGee, Gerard Anthony

    1993-01-01

    This work involves the characterisation of the electrochemical decomposition of chlorinated hydrocarbons. A variety of methods were employed involving the use of catalytic reagents to enhance the rate at which chlorinated organic compounds are reduced. The first reagent used was oxygen which was electrochemically reduced to superoxide in nonaqueous solvents. Superoxide is a reactive intermediate and decomposes chlorinated hydrocarbons. However it was found that since the rate of reaction betw...

  15. Replacement of Retinyl Esters by Polyunsaturated Triacylglycerol Species in Lipid Droplets of Hepatic Stellate Cells during Activation

    NARCIS (Netherlands)

    Testerink, N.; Ajat, M.A.; Houweling, M.; Brouwers, J.F.; Pully, V.V.; Manen, van H.J.; Otto, C.; Helms, J.B.; Vaandrager, A.B.

    2012-01-01

    Activation of hepatic stellate cells has been recognized as one of the first steps in liver injury and repair. During activation, hepatic stellate cells transform into myofibroblasts with concomitant loss of their lipid droplets (LDs) and production of excessive extracellular matrix. Here we aimed t

  16. Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress.

    Science.gov (United States)

    Colville, Louise; Bradley, Emma L; Lloyd, Antony S; Pritchard, Hugh W; Castle, Laurence; Kranner, Ilse

    2012-11-01

    The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography-mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss.

  17. A comparison of chlorinated organic material produced by chlorine and chlorine dioxide bleaching

    Energy Technology Data Exchange (ETDEWEB)

    McKaque, A.B.; Reeve, D.W. [Univ. of Toronto (Canada)

    1995-12-31

    Chlorine and chlorine dioxide react differently with pulp during bleaching and produce different types of organic by-products. The main differences are the large reduction in the amount of AOX (adsorbable organic halogen) in the effluent and EOX (extractable organic halogen) in the pulp. This talk reviews the differences in the amounts and types of chlorinated organic by-products produced by the two different bleaching agents.

  18. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    Science.gov (United States)

    Taylor, Robert H.; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains were more resistant to chlorine than were cells of the more rapidly growing strains. Water-grown cells were 10-fold more resistant than medium-grown cells. Disinfectant resistance may be one factor promoting the persistence of M. avium in drinking water. PMID:10742264

  19. Photodynamic activity of the boronated chlorin e6 amide in artificial and cellular membranes.

    Science.gov (United States)

    Antonenko, Yuri N; Kotova, Elena A; Omarova, Elena O; Rokitskaya, Tatyana I; Ol'shevskaya, Valentina A; Kalinin, Valery N; Nikitina, Roza G; Osipchuk, Julia S; Kaplan, Mikhail A; Ramonova, Alla A; Moisenovich, Mikhail M; Agapov, Igor I; Kirpichnikov, Mikhail P

    2014-03-01

    Photodynamic tumor-destroying activity of the boronated chlorin e6 derivative BACE (chlorin e6 13(1)-N-{2-[N-(1-carba-closo-dodecaboran-1-yl)methyl]aminoethyl}amide-15(2), 17(3)-dimethyl ester), previously described in Moisenovich et al. (2010) PLoS ONE 5(9) e12717, was shown here to be enormously higher than that of unsubstituted chlorin e6, being supported by the data on much higher photocytotoxicity of BACE in M-1 sarcoma cell culture. To validate membrane damaging effect as the basis of the enhanced tumoricidal activity, BACE was compared with unsubstituted chlorin e6 in the potency to photosensitize dye leakage from liposomes, transbilayer lipid flip-flop, inactivation of gramicidin A ionic channels in planar lipid membranes and erythrocyte hemolysis. In all the models comprising artificial and cellular membranes, the photodynamic effect of BACE exceeded that of chlorin e6. BACE substantially differed from chlorin e6 in the affinity to liposomes and erythrocytes, as monitored by fluorescence spectroscopy, flow cytometry and centrifugation. The results support the key role of membrane binding in the photodynamic effect of the boronated chlorin e6 amide.

  20. Thermodynamic equilibrium diagram of the chlorine-titanium system

    Institute of Scientific and Technical Information of China (English)

    DU Ailing; GUO Xiaofei; ZHANG Heming; LIU Jiang

    2005-01-01

    The chemical and electrochemical equilibria of the chlorine-titanium system in the presence of gaseous phase were investigated. Many species, which consisted of chlorine and titanium, were considered. Various thermodynamic equilibria were calculated in the different pressures at different temperatures. The calculated results were shown as log p-1/T and E-T diagrams. These diagrams may be used as important tools for corrosion study and titanium production. The diagrams are also used to thermodynamically determine the existence areas of various species and so on.

  1. Observations of Major Stratospheric Chlorine Species.

    Science.gov (United States)

    1983-10-24

    AFGL as cryofrosts within the two tri-samplers for subsequent warm -up and analyses. Chemiluminescence anal- ysis to determine oxides of nitrogen...Atmlos. Envrirov. 15:1559-1568. 12. The Stratosphr 91 Theorys and Measurements, \\ orld Meteorological Or- gaizt o Globa TO one -1 es earch

  2. Uptake, turnover and distribution of chlorinated fatty acids in aquatic biota

    Energy Technology Data Exchange (ETDEWEB)

    Bjoern, Helena

    1999-09-01

    Chlorinated fatty acids (CIFAs) are the major contributors of extractable, organically bound chlorine in fish lipids. A known anthropogenic source of CIFAs is chlorine bleached pulp production. Additional anthropogenic sources may exist, e.g., chlorine-containing discharge from industrial and household waste and they may also occur naturally. CIFAs have a wide geographic distribution. They have, for instance, been identified in fish both from Alaskan and Scandinavian waters. In toxicological studies of CIFAs, the most pronounced effects have been found in reproductive related processes. CIFAs have also been shown to disrupt cell membrane functions. The present study was carried out to further characterise the ecotoxicological properties of CIFAs and their presence in biota. To investigate the biological stability of CIFAs, two experiments were carried out using radiolabelled chlorinated and non-chlorinated fatty acids. In both experiments, CIFAs were taken up from food by fish and assimilated to lipids. From the first experiment it was concluded that the chlorinated fatty acid investigated was turned over in the fish to a lower degree than the non-chlorinated analogue. In the second experiment, the transfer of a chlorinated fatty acid was followed over several trophic levels and the chlorinated fatty acid was transferred to the highest trophic level. In samples with differing loads of persistent organic pollutants (POPs) from both fish and marine mammals, high concentrations and diversity of CIFAs were detected. This was also observed in samples with low POP concentration. Chlorohydroxy fatty acids made up a considerable portion of the CIFAs in certain samples, both from limnic fish and marine mammals. CIFAs in fish were found to be bound in complex lipids such as triacylglycerols (storage lipids) and phospholipids, as well as in acyl sterols (membrane lipids). In the marine mammals investigated, high concentrations of CIFAs were mainly bound in phospholipids. If

  3. Localization of methyl-branched ceramide [EOS] species within the long-periodicity phase in stratum corneum lipid model membranes: A neutron diffraction study.

    Science.gov (United States)

    Eichner, Adina; Sonnenberger, Stefan; Dobner, Bodo; Hauß, Thomas; Schroeter, Annett; Neubert, Reinhard H H

    2016-11-01

    The outermost layer of the mammalian skin, the stratum corneum (SC), is a very thin structure and realizes simultaneously the main barrier properties. The penetration barrier for xenobiotica is mostly represented by a complex lipid matrix. There is great interest in the subject of getting information about the arrangement of the lipids, which are mainly ceramides (CER), free fatty acids (FFA) and cholesterol (CHOL). SC lipid model membranes containing synthetically derived lipids in a non-physiological ratio were investigated. To compare the study to a former experiment, a methyl-branched ceramide [EOS] species in presence of the ultra-long chain CER[AP], CHOL and behenic acid (23/10/33/33, wt%) was applied. The membrane structure was studied using the very versatile technique of neutron diffraction. We were able to identify a long-periodicity phase (LPP) with a size of 114Å or 118Å with CER[EOS]-br in a ratio of >60wt% of the ceramides. Furthermore, we figured out two additional coexisting short-periodicity phases (SPP) with repeat distances of 48Å and 45Å, respectively. Partial deuterations of CER[EOS]-br and CER[AP] enabled the localization of the molecules within the multiphase system. CER[EOS]-d3 was present in the LPP, but absent in both SPP. CER[AP]-d3 was determined in both short phases but not localized within the LPP. Besides, we revealed influences of humidity and time with respect to the long-periodicity phase. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Shock-tube pyrolysis of chlorinated hydrocarbons - Formation of soot

    Science.gov (United States)

    Frenklach, M.; Hsu, J. P.; Miller, D. L.; Matula, R. A.

    1986-01-01

    Soot formation in pyrolysis of chlorinated methanes, their mixtures with methane, and chlorinated ethylenes were studied behind reflected shock waves by monitoring the attenuation of an He-Ne laser beam. An additional single-pulse shock-tube study was conducted for the pyrolysis of methane, methyl chloride, and dichloromethane. The experiments were performed at temperatures 1300-3000 K, pressures of 0.4-3.6 bar, and total carbon atom concentrations of 1-5 x 10 to the 17th atoms cu cm. The amounts of soot produced in the pyrolysis of chlorinated hydrocarbons are larger than that of their nonchlorinated counterparts. The sooting behavior and product distribution can be generally explained in terms of chlorine-catalyzed chemical reaction mechanisms. The pathway to soot from chlorinated methanes and ethylenes with high H:Cl ratio proceeds via the formation of C2H, C2H2, and C2H3 species. For chlorinated hydrocarbons with low H:Cl ratio, the formation of C2 and its contribution to soot formation at high temperatures becomes significant. There is evidence for the importance of CHCl radical and its reactions in the pyrolysis of dichloromethane.

  5. Shock-tube pyrolysis of chlorinated hydrocarbons - Formation of soot

    Science.gov (United States)

    Frenklach, M.; Hsu, J. P.; Miller, D. L.; Matula, R. A.

    1986-01-01

    Soot formation in pyrolysis of chlorinated methanes, their mixtures with methane, and chlorinated ethylenes were studied behind reflected shock waves by monitoring the attenuation of an He-Ne laser beam. An additional single-pulse shock-tube study was conducted for the pyrolysis of methane, methyl chloride, and dichloromethane. The experiments were performed at temperatures 1300-3000 K, pressures of 0.4-3.6 bar, and total carbon atom concentrations of 1-5 x 10 to the 17th atoms cu cm. The amounts of soot produced in the pyrolysis of chlorinated hydrocarbons are larger than that of their nonchlorinated counterparts. The sooting behavior and product distribution can be generally explained in terms of chlorine-catalyzed chemical reaction mechanisms. The pathway to soot from chlorinated methanes and ethylenes with high H:Cl ratio proceeds via the formation of C2H, C2H2, and C2H3 species. For chlorinated hydrocarbons with low H:Cl ratio, the formation of C2 and its contribution to soot formation at high temperatures becomes significant. There is evidence for the importance of CHCl radical and its reactions in the pyrolysis of dichloromethane.

  6. Disinfection kinetics of murine norovirus using chlorine and chlorine dioxide.

    Science.gov (United States)

    Lim, Mi Young; Kim, Ju-Mi; Ko, Gwangpyo

    2010-05-01

    We determined the disinfection efficiency of chlorine and chlorine dioxide (ClO(2)) using murine norovirus (MNV) and coliphage MS2 as surrogates for human norovirus. Experiments were performed in oxidant demand-free buffer (pH 7.2) at 5 degrees C and 20 degrees C. The extent of virus inactivation by a disinfectant was quantified using three different analytical methods: plaque, short template real-time TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR), and long template RT-PCR assays. Rapid inactivation of MNV by both chlorine and chlorine dioxide was observed by the plaque assay. According to the efficiency factor Hom model, Ct values of 0.314mg/Lmin and 0.247mg/Lmin were required for a 4-log reduction of MNV at 5 degrees C by chlorine and chlorine dioxide, respectively. Lower Ct values were required at 20 degrees C. Both long template and short template RT-PCR assays significantly underestimated the virus inactivation compared to the plaque assay. Our study demonstrates that adequate treatment of water with either chlorine or ClO(2) is likely to effectively control the waterborne transmission of human norovirus.

  7. Inactivation of Chironomid Larvae with Chlorine Dioxide and Chlorine

    Institute of Scientific and Technical Information of China (English)

    SUN Xin-bin; CUI Fu-yi

    2008-01-01

    Chironomid larvae propagate prolifically in eutrophic water body and they cannot be exterminated by conventional disinfection process.The inactivation effects of chlorine and chlorine dioxide on Chironomid larvae were investigated and some boundary values in practice were determined under conditions of various oxidant dosage,organic precursor concentration and pH value.In addition,removal effect of differmt pre-oxidation combined with coagulation process on Chironomid larvae in law water was evaluated.It was found that chlorine dioxide possessed better inactivation effect than chlorine.Complete inactivation of Chironomid larvae in raw water was resulted by 1.5mg/L of chlorine dioxide with 30min of contact time. Additionally,the ocgallic precursor concentration,pH value had little influence on the inactivation effect.The coagulation jar test showed that Chironomid larvae in the raw water could be completely ronxwed by chlorine dioxide pre-oxidation in combination with the omgulation process at chlorine dioxide dosage of 0.8 mg/L.

  8. Chlorine activation in the dark polar vortices

    Science.gov (United States)

    Grooß, Jens-Uwe; Spang, Reinhold; Wegner, Tobias; Rolf, Müller

    2017-04-01

    Simulations of polar stratospheric chemistry have been performed with the state-of-the-art Lagrangian Chemistry Transport Model CLaMS for both Antarctic and Arctic winters. CLaMS includes a Lagrangian sedimentation scheme that is able to successfully simulate the vertical NOy redistribution due to the sedimentation of large NAT particles. In general, observations of stratospheric trace species are very well reproduced by the model. However, during the time of the onset of chlorine activation, the simulations significantly over-estimate the HCl mixing ratio inside the polar vortex core where little sunlight is available. This discrepancy is seen in both hemispheres and points to some unrecognized process in stratospheric chemistry. The spatial and temporal development of the discrepancy is investigated in detail in order to search for possible processes missing in the model. HCl depletion rates derived from MLS observations correlate well with ice PSC detections derived from MIPAS. Possible reasons for this discrepancy in chlorine activation will be discussed. Since the discrepancy is mainly seen during the beginning of the chlorine activation period where the ozone loss rates are low, the impact on the overall ozone loss over the course of the winter and spring is rather low.

  9. Identification of molecular species of simple lipids by normal phase liquid chromatography-positive electrospray tandem mass spectrometry, and application of developed methods in comprehensive analysis of low erucic acid rapeseed oil lipids

    Science.gov (United States)

    Kalo, P. J.; Ollilainen, V.; Rocha, J. M.; Malcata, F. X.

    2006-07-01

    Mono-, di- and triacylglycerol (MAG, DAG, TAG), sterol ester (SE), free sterol (S) and free fatty acid (FFA) standards were analyzed in the presence of ammonium ions and ammonia by flow injection MS2 and MS3, and by normal phase-liquid chromatography (NP-LC) MS2 positive electrospray ionization (ESI) mass spectrometry (MS). The MS data recorded for ammonium adducts ([M + NH4]+) of TAGs, DAGs, and MAGs were consistent with stepwise fragmentation mechanisms. In the first step, ammonium ion in [M + NH4]+ donates proton to acylglycerol and ammonia is released. In the second step, FFA is cleaved from protonated TAG, water from protonated 1,3-DAG and MAG, both FFA and water from protonated 1,2-DAG, hence leading to formation of [DAG]+ ion from TAG and 1,3-DAG, [DAG]+ and [MAG]+ ions from 1,2-DAG, and [MAG]+ ion from MAG. In the third step, [DAG]+ ion of TAG is fragmented to yield [Acyl]+, [Acyl + 74]+, [DAG - 74]+ ions, [DAG] ion of 1,3-DAG to [Acyl]+ ions, and [MAG]+ ion of MAG to protonated FAs, which are decomposed to water and [Acyl]+ ions in the fourth step. A stepwise mechanism for fragmentation of FFA was also evident from MS2 and MS3 data. Molecular species of low erucic acid rapeseed oil simple lipids were identified from characteristic ions produced in the NP-LC-ESI-MS2 of [M + NH4]+ ions. The percentage composition of the molecular species of each lipid class was calculated from integrated extracted ion chromatograms of [(M + NH4)]+ ions of SE, TAG, MAG, and FFA, of the sum of [(M + NH4)]+ and [(M + NH4) - NH3 - H2O]+ ions of both regioisomers of DAGs, and of sterol fragment ions of S.

  10. Natural Chlorinated Auxins Labeled with Radioactive Chloride in Immature Seeds

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1975-01-01

    Immature seeds were harvested from 15 species grown in perlite/vermiculite containing 36Cl-, but with very low levels of cold Cl-. Autoradiograms of one- and two-dimensional thin layer chromatograms of butanol extracts of lyophilized seeds indicated several radioactive compounds besides the 36Cl......- in many species. In pea the radioactivity cochromatographed with 4-(or 6-)chloroindolyl-3-acetic acid and its methyl ester; in other species radioactivity was found near these chlorinated indolyl-acetic acid markers....

  11. Chlorination byproducts, their toxicodynamics and removal from drinking water.

    Science.gov (United States)

    Gopal, Krishna; Tripathy, Sushree Swarupa; Bersillon, Jean Luc; Dubey, Shashi Prabha

    2007-02-01

    No doubt that chlorination has been successfully used for the control of water borne infections diseases for more than a century. However identification of chlorination byproducts (CBPs) and incidences of potential health hazards created a major issue on the balancing of the toxicodynamics of the chemical species and risk from pathogenic microbes in the supply of drinking water. There have been epidemiological evidences of close relationship between its exposure and adverse outcomes particularly the cancers of vital organs in human beings. Halogenated trihalomethanes (THMs) and haloacetic acids (HAAs) are two major classes of disinfection byproducts (DBPs) commonly found in waters disinfected with chlorine. The total concentration of trihalomethanes and the formation of individual THM species in chlorinated water strongly depend on the composition of the raw water, on operational parameters and on the occurrence of residual chlorine in the distribution system. Attempts have been made to develop predictive models to establish the production and kinetics of THM formations. These models may be useful for operational purposes during water treatment and water quality management. It is also suggested to explore some biomarkers for determination of DBP production. Various methods have been suggested which include adsorption on activated carbons, coagulation with polymer, alum, lime or iron, sulfates, ion exchange and membrane process for the removal of DBPs. Thus in order to reduce the public health risk from these toxic compounds regulation must be inforced for the implementation of guideline values to lower the allowable concentrations or exposure.

  12. Chlorine dioxide as phenol and H2S scavenger - formation of halogenated phenols and subsequent environmental risk

    Energy Technology Data Exchange (ETDEWEB)

    Melbye, Alf G.; Faksness, Liv-Guri; Knudsen, Boerre Leif

    2006-03-15

    Formation of halogenated phenols as side products from treatment of produced water with aqueous chlorine dioxide has been investigated. The literature describes formation of halogenated hydrocarbons in effluent treatment using chlorine, hypochlorite and chlorine dioxide. A new chlorine dioxide product, originally intended as a H2S scavenger in the oil and gas industry, has been tested both as a phenol scavenger and H2S-scavenger for produced water applications. The concern about the possible formation of halogenated by-products initiated laboratory testing of chlorine dioxide as phenol and H2S scavenger for produced water applications. The tests also included synthetic matrixes containing phenols, and the tests show that halogenated phenols, mainly brominated species, are found in produced water after treatment with chlorine dioxide. Due to potential environmental risk from halogenated organic contaminants, the use of chlorine dioxide as phenol and H2S scavenger is not recommended. (Author)

  13. Lipid exchange by ultracentrifugation

    DEFF Research Database (Denmark)

    Drachmann, Nikolaj Düring; Olesen, Claus

    2014-01-01

    Lipids play an important role in maintaining P-type ATPase structure and function, and often they are crucial for ATPase activity. When the P-type ATPases are in the membrane, they are surrounded by a mix of different lipids species with varying aliphatic chain lengths and saturation......, and the complex interplay between the lipids and the P-type ATPases are still not well understood. We here describe a robust method to exchange the majority of the lipids surrounding the ATPase after solubilisation and/or purification with a target lipid of interest. The method is based on an ultracentrifugation...... step, where the protein sample is spun through a dense buffer containing large excess of the target lipid, which results in an approximately 80-85 % lipid exchange. The method is a very gently technique that maintains protein folding during the process, hence allowing further characterization...

  14. Improved method generates more chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, R.W.; Kosinski, A.J.; Baker, R.J.

    1980-10-01

    The addition of acid can greatly improve the chlorine-chlorite process and enhance the use of chlorine dioxide as an alternative to chlorine for disinfection. The process is economical for use in taste and odor control, and for manganese, oxidation. The maximum yield is obtained using no excess chlorine, and the amount of unreacted sodium chlorite and chlorine in the product stream is reduced. (1 diagram, 4 graphs, 9 references)

  15. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  16. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  17. Extractions of High Quality RNA from the Seeds of Jerusalem Artichoke and Other Plant Species with High Levels of Starch and Lipid

    Directory of Open Access Journals (Sweden)

    Tanupat Mornkham

    2013-04-01

    Full Text Available Jerusalem artichoke (Helianthus tuberosus L. is an important tuber crop. However, Jerusalem artichoke seeds contain high levels of starch and lipid, making the extraction of high-quality RNA extremely difficult and the gene expression analysis challenging. This study was aimed to improve existing methods for extracting total RNA from Jerusalem artichoke dry seeds and to assess the applicability of the improved method in other plant species. Five RNA extraction methods were evaluated on Jerusalem artichoke seeds and two were modified. One modified method with the significant improvement was applied to assay seeds of diverse Jerusalem artichoke accessions, sunflower, rice, maize, peanut and marigold. The effectiveness of the improved method to extract total RNA from seeds was assessed using qPCR analysis of four selected genes. The improved method of Ma and Yang (2011 yielded a maximum RNA solubility and removed most interfering substances. The improved protocol generated 29 to 41 µg RNA/30 mg fresh weight. An A260/A280 ratio of 1.79 to 2.22 showed their RNA purity. Extracted RNA was effective for downstream applications such as first-stranded cDNA synthesis, cDNA cloning and qPCR. The improved method was also effective to extract total RNA from seeds of sunflower, rice, maize and peanut that are rich in polyphenols, lipids and polysaccharides.

  18. Taraxasterol inhibits cigarette smoke-induced lung inflammation by inhibiting reactive oxygen species-induced TLR4 trafficking to lipid rafts.

    Science.gov (United States)

    Xueshibojie, Liu; Duo, Yu; Tiejun, Wang

    2016-10-15

    Taraxasterol, a pentacyclic-triterpene isolated from Taraxacum officinale, has been demonstrated to have anti-inflammatory effects. However, the protective effects of taraxasterol against cigarette smoke (CS)-induced lung inflammation have not been reported. This study aimed to investigate the protective effects and mechanism of taraxasterol on CS-induced lung inflammation in mice. CS-induced mouse lung inflammation model was used to investigate the protective effects of taraxasterol in vivo. Human bronchial epithelial cells (HBECs) were used to investigate the protective mechanism of taraxasterol in vitro. The results showed that taraxasterol attenuated CS-induced lung pathological changes, inflammatory cells infiltration, inflammatory cytokines TNF-α, IL-6 and IL-1β production. Taraxasterol also up-regulated CS-induced glutathione (GSH) production. In vitro, taraxasterol was found to inhibit CS-induced reactive oxygen species production, recruitment of TLR4 into lipid rafts, NF-κB activation, and IL-8 production. Furthermore, our results showed that antioxidant N-acetyl-L-cysteine (NAC) significantly inhibited CS-induced recruitment of TLR4 into lipid rafts as well as IL-8 production. In conclusion, our results suggested that taraxasterol had protective effects of CS-induced lung inflammation.

  19. Extractions of High Quality RNA from the Seeds of Jerusalem Artichoke and Other Plant Species with High Levels of Starch and Lipid.

    Science.gov (United States)

    Mornkham, Tanupat; Wangsomnuk, Preeya Puangsomlee; Fu, Yong-Bi; Wangsomnuk, Pinich; Jogloy, Sanun; Patanothai, Aran

    2013-04-29

    Jerusalem artichoke (Helianthus tuberosus L.) is an important tuber crop. However, Jerusalem artichoke seeds contain high levels of starch and lipid, making the extraction of high-quality RNA extremely difficult and the gene expression analysis challenging. This study was aimed to improve existing methods for extracting total RNA from Jerusalem artichoke dry seeds and to assess the applicability of the improved method in other plant species. Five RNA extraction methods were evaluated on Jerusalem artichoke seeds and two were modified. One modified method with the significant improvement was applied to assay seeds of diverse Jerusalem artichoke accessions, sunflower, rice, maize, peanut and marigold. The effectiveness of the improved method to extract total RNA from seeds was assessed using qPCR analysis of four selected genes. The improved method of Ma and Yang (2011) yielded a maximum RNA solubility and removed most interfering substances. The improved protocol generated 29 to 41 µg RNA/30 mg fresh weight. An A260/A280 ratio of 1.79 to 2.22 showed their RNA purity. Extracted RNA was effective for downstream applications such as first-stranded cDNA synthesis, cDNA cloning and qPCR. The improved method was also effective to extract total RNA from seeds of sunflower, rice, maize and peanut that are rich in polyphenols, lipids and polysaccharides.

  20. Degradation of carbamazepine by UV/chlorine advanced oxidation process and formation of disinfection by-products.

    Science.gov (United States)

    Zhou, Shiqing; Xia, Ying; Li, Ting; Yao, Tian; Shi, Zhou; Zhu, Shumin; Gao, Naiyun

    2016-08-01

    Pharmaceuticals in water are commonly found and are not efficiently removed by current treatment processes. Degradation of antiepileptic drug carbamazepine (CBZ) by UV/chlorine advanced oxidation process was systematically investigated in this study. The results showed that the UV/chlorine process was more effective at degrading CBZ than either UV or chlorination alone. The CBZ degradation followed pseudo-first order reaction kinetics, and the degradation rate constants (kobs) were affected by the chlorine dose, solution pH, and natural organic matter concentration to different degrees. Degradation of CBZ greatly increased with increasing chlorine dose and decreasing solution pH during the UV/chlorine process. Additionally, the presence of natural organic matter in the solution inhibited the degradation of CBZ. UV photolysis, chlorination, and reactive species (hydroxyl radical •OH and chlorine atoms •Cl) were identified as responsible for CBZ degradation in the UV/chlorine process. Finally, a degradation pathway for CBZ in the UV/chlorine process was proposed and the formation potentials of carbonaceous and nitrogenous disinfection by-products were evaluated. Enhanced formation of trichloroacetic acid, dichloroacetonitrile, and trichloronitromethane precursors should be considered when applying UV/chlorine advanced oxidation process to drinking water.

  1. Chlorination of tramadol: Reaction kinetics, mechanism and genotoxicity evaluation.

    Science.gov (United States)

    Cheng, Hanyang; Song, Dean; Chang, Yangyang; Liu, Huijuan; Qu, Jiuhui

    2015-12-01

    Tramadol (TRA) is one of the most detected analgesics in environmental matrices, and it is of high significance to study the reactivity of TRA during chlorination considering its potential toxicity to the environment. The chlorine/TRA reaction is first order with respect to the TRA concentration, and a combination of first-order and second-order with respect to chlorine concentration. The pH dependence of the observed rate constants (kobs) showed that the TRA oxidation reactivity increased with increasing pH. kobs can be quantitatively described by considering all active species including Cl2, Cl2O and HOCl, and the individual rate constants of HOCl/TRA(0), HOCl/TRAH(+), Cl2/TRA and Cl2O/TRA reactions were calculated to be (2.61±0.29)×10(3)M(-1)s(-1), 14.73±4.17M(-1)s(-1), (3.93±0.34)×10(5)M(-1)s(-1) and (5.66±1.83)×10(6)M(-1)s(-1), respectively. Eleven degradation products were detected with UPLC-Q-TOF-MS, and the corresponding structures of eight products found under various pH conditions were proposed. The amine group was proposed to be the initial attack site under alkaline pH conditions, where reaction of the deprotonated amine group with HOCl is favorable. Under acidic and neutral pH conditions, however, two possible reaction pathways were proposed. One is an electrophilic substitution on the aromatic ring, and another is an electrophilic substitution on the nitrogen, leading to an N-chlorinated intermediate, which can be further oxidized. Finally, the SOS/umu test showed that the genotoxicity of TRA chlorination products increased with increasing dosage of chlorine, which was mostly attributed to the formation of some chlorine substitution products.

  2. Degradation of DEET and Caffeine under UV/Chlorine and Simulated Sunlight/Chlorine Conditions.

    Science.gov (United States)

    Sun, Peizhe; Lee, Wan-Ning; Zhang, Ruochun; Huang, Ching-Hua

    2016-12-20

    Photoactivation of aqueous chlorine could promote degradation of chlorine-resistant and photochemically stable chemicals accumulated in swimming pools. This study investigated the degradation of two such chemicals, N,N-diethyl-3-methylbenzamide (DEET) and caffeine, by low pressure ultraviolet (UV) light and simulated sunlight (SS) activated free chlorine (FC) in different water matrices. Both DEET and caffeine were rapidly degraded by UV/FC and SS/FC but exhibited different kinetic behaviors. The degradation of DEET followed pseudo-first-order kinetics, whereas the degradation of caffeine accelerated with reaction. Mechanistic study revealed that, under UV/FC, ·OH and Cl· were responsible for degradation of DEET, whereas ClO· related reactive species (ClOrrs), generated by the reaction between FC and ·OH/Cl·, played a major role in addition to ·OH and Cl· in degrading caffeine. Reaction rate constants of DEET and caffeine with the respective radical species were estimated. The imidazole moiety of caffeine was critical for the special reactivity with ClOrrs. Water matrix such as pH had a stronger impact on the UV/FC process than the SS/FC process. In saltwater matrix under UV/FC and SS/FC, the degradation of DEET was significantly inhibited, but the degradation of caffeine was much faster than that in nonsalty solutions. The interaction between Br(-) and Cl(-) may play an important role in the degradation of caffeine by UV/FC in saltwater. Reaction product analysis showed similar product patterns by UV/FC and SS/FC and minimal formation of chlorinated intermediates and disinfection byproducts.

  3. Reserve carbohydrates and lipids from the seeds of four tropical tree species with different sensitivity to desiccation

    Directory of Open Access Journals (Sweden)

    Juliana Iura de Oliveira Mello

    2010-08-01

    Full Text Available Considering the importance of water content for the conservation and storage of seeds, and the involvement of soluble carbohydrates and lipids for embryo development, a comparative study was carried out among the seeds of Inga vera (ingá, Eugenia uniflora (pitanga, both classified as recalcitrant, and Caesalpinia echinata (brazilwood and Erythrina speciosa (mulungu, considered as orthodox seeds. Low concentrations of cyclitols (0.3-0.5%, raffinose family oligosaccharides (ca. 0.05% and unsaturated fatty acids (0-19% were found in the seeds of ingá and pitanga, while larger amounts of cyclitols (2-3% and raffinose (4.6-13% were found in brazilwood and mulungu, respectively. These results, in addition to higher proportions of unsaturated fatty acids (53-71% in orthodox seeds, suggested that sugars and lipids played important role in water movement, protecting the embryo cell membranes against injuries during dehydration.Os compostos de reserva das sementes, além de suprirem energia para o desenvolvimento embrionário, desempenham importantes funções relacionadas à proteção celular contra secagem e congelamento. Considerando a importância do teor de água para a conservação e para o armazenamento de sementes de espécies arbóreas e o envolvimento dos carboidratos solúveis e de lipídios nesses processos, foi realizada uma análise comparativa desses compostos em sementes de Inga vera (ingá e Eugenia uniflora (pitanga, consideradas recalcitrantes, e em Caesalpinia echinata (pau-brasil e Erythrina speciosa (mulungu, com comportamento ortodoxo. Baixas concentrações de ciclitóis (0,3-0,5%, de oligossacarídeos da série da rafinose (0,05% e de ácidos graxos insaturados (0-19% foram encontradas em sementes de ingá e pitanga, enquanto maiores quantidades de ciclitóis (2-3% e de rafinose (4,6-13% foram encontradas nas sementes de pau-brasil e mulungu, respectivamente. Estes resultados, juntamente com as altas proporções de

  4. Responses of plant biomass, photosynthesis and lipid peroxidation to warming and precipitation change in two dominant species (Stipa grandis and Leymus chinensis) from North China Grasslands.

    Science.gov (United States)

    Song, Xiliang; Wang, Yuhui; Lv, Xiaomin

    2016-03-01

    Influential factors of global change affect plant carbon uptake and biomass simultaneously. Although the effects from warming and precipitation change have been extensive studied separately, the responses of plant biomass, photosynthesis, and lipid peroxidation to the interaction of these factors are still not fully understood. In this study, we examined the physiological responses of two dominant plant species from grasslands of northern China with different functional traits to combinations of five simulated warming patterns and five simulated precipitation patterns in environment-controlled chambers. Our results showed that the biomass, net CO 2 assimilation rate (P n), maximal efficiency of photosystem II photochemistry (F v/F m), and chlorophyll content (Chl) of Stipa grandis and Leymus chinensis were enhanced by moderate warming and plus precipitation, but they declined drastically with high temperature and drought. High temperature and drought also led to significant malondialdehyde (MDA) accumulation, which had a negative correlation with leaf biomass. The lower level of lipid peroxidation in leaves of S. grandis suggests that this species is better protected from oxidative damage under heat stress, drought stress and their interactive conditions than L. chinensis. Using the subordinate function values method, we found S. grandis to be more sensitive to climate change than L. chinensis and the gross biomass and root biomass of S. grandis and the leaf biomass of L. chinensis were most sensitive to climate change. Furthermore, the P n of both S. grandis and L. chinensis had a significant linear relationship with F v/F m and Chl, indicating that carbon assimilation may be caused by nonstomatal limitations.

  5. The geochemistry of stable chlorine and bromine isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Eggenkamp, Hans [Onderzock and Beleving, Bussum (Netherlands)

    2014-11-01

    First book solely dedicated to the geochemistry of chlorine and bromine isotopes. Detailed description of analytical techniques, including their advantages and disadvantages. Indication of research fields where measurement of these isotopes is especially useful. This book provides detailed information on the history, analysis and applications of chlorine and bromine isotope geochemistry. Chlorine and bromine are geochemically unique as they prefer to exist as single charged negative ions. For this reason isotope fractionation reflects mostly processes that are not related to changes in the redox state and this fractionation is generally modest. The book will describe the processes that are most easily detected using these isotopes. Also isotope variations, and processes that cause them, measured in oxidised species such as perchlorates and in organic molecules will be described in this book.

  6. Chlorination of Carbon Nanotubes Obtained on the Different Metal Catalysts

    Directory of Open Access Journals (Sweden)

    Iwona Pełech

    2013-01-01

    Full Text Available In this paper, a chlorination method is proposed for simultaneous purification and functionalization of carbon nanotubes, thus increasing their ability to use. Carbon nanotubes were obtained by CVD method through ethylene decomposition on the nanocrystalline iron or cobalt or bimetallic iron-cobalt catalysts. The effects of temperature (50, 250, and 450°C in the case of carbon nanotubes obtained on the Fe-Co catalyst and type of catalyst (Fe, Co, Fe/Co on the effectiveness of the treatment and functionalization were tested. The phase composition of the samples was determined using the X-ray diffraction method. The quantitative analysis of metal impurity content was validated by means of the thermogravimetric analysis. Using X-ray Photoelectron Spectroscopy (XPS, Energy Dispersive Spectroscopy (EDS analysis, and also Mohr titration method, the presence of chlorine species on the surface of chlorinated samples was confirmed.

  7. Cleaning without chlorinated solvents

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.M.; Simandl, R.F.

    1994-12-31

    Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

  8. Coagulation properties of anelectrochemically prepared polyaluminum chloride containing active chlorine

    Institute of Scientific and Technical Information of China (English)

    HU Chengzhi; LIU Huijuan; QU Jiuhui

    2006-01-01

    With high content of the Al13 species and the active chloride, an electrochemically prepared polyaluminum chloride (E-PACl) presents integrated efficiency of coagulation and oxidation. The coagulation properties of E-PACl were systemically investigated through jar tests in the various water quality conditions. The active chlorine in E-PACl can significantly influence the coagulation behavior due to the active chlorine preoxidation, which can change the surface charge characteristic of organic matter (OM) in water. The active chlorine preoxidation could improve the E-PACl coagulation efficiency if the water possessed the characteristics of relatively low OM content (2 mg/L) and high hardness (278 mg CaCO3/L). In the water with medium content of OM (5 mg/L), dosage would be a crucial factor to decide whether the active chlorine in E-PACl aided coagulation process or not. Comparing with alkaline condition, active chlorine would show a more significant influence on the coagulation process in acidic region.

  9. Lipid Profile

    Science.gov (United States)

    ... AACC products and services. Advertising & Sponsorship: Policy | Opportunities Lipid Profile Share this page: Was this page helpful? Also ... as: Lipid Panel; Coronary Risk Panel Formal name: Lipid Profile Related tests: Cholesterol ; HDL Cholesterol ; LDL Cholesterol ; Triglycerides ; ...

  10. Fatty Acid Composition of the Muscle Lipids of Five Fish Species in Işıklı and Karacaören Dam Lake, Turkey

    Directory of Open Access Journals (Sweden)

    Ozcan Baris Citil

    2014-01-01

    Full Text Available Total fatty acid composition of muscle lipids in some fish species (Cyprinus carpio (Işıklı Dam Lake, Tinca tinca (Işıklı Dam Lake, Scardinius erythrophthalmus (Işıklı Dam Lake, Cyprinus carpio (Karacaören Dam Lake, and Carassius carassius (Karacaören Dam Lake was determined by gas chromatography. Polyunsaturated fatty acids (PUFAs of Cyprinus carpio (Işıklı Dam Lake were found higher than PUFA of other species. Palmitic acid was the highest saturated fatty acid (SFA in Tinca tinca (24.64%. Oleic acid was the highest monounsaturated fatty acid (MUFAs in Cyprinus carpio (Işıklı Dam Lake (19.25%. The most abundant polyunsaturated fatty acid in Scardinius erythrophthalmus was docosahexaenoic acid (DHA (17.94%. Total ω3 fatty acid composition was higher than the total ω6 fatty acids of Cyprinus carpio in both dam lakes. ω3/ω6 rates in Cyprinus carpio (Işıklı Dam Lake, Tinca tinca, Scardinius erythrophthalmus, Cyprinus carpio (Karacaören, and Carassius carassius were 2.12, 1.19, 2.15, 2.87, and 2.82, respectively.

  11. pH significantly affects removal of trace antibiotics in chlorination of municipal wastewater.

    Science.gov (United States)

    Li, Bing; Zhang, Tong

    2012-07-01

    The effect of pH on chlorination behaviors of 12 antibiotics, including β-lactams, sulfonamides, fluoroquinolones, tetracyclines, macrolides, and others at environmentally relevant concentrations was systematically examined in the effluent matrix of activated sludge process. The removal of most antibiotics (except cefalexin and tetracycline) significantly depended on pH in the range of 5.5-8.5. The elimination rates of ciprofloxacin, norfloxacin, anhydro-erythromycin, and roxithromycin increased while that of sulfamethoxazole decreased significantly with the increase of pH. Sulfadiazine, ofloxacin, and trimethoprim exhibited the highest reactivity with free available chlorine under the pH of 6-7, 7, and 7.5, respectively. Not only the free available chlorine species (HOCl and OCl⁻), but also the antibiotics species (cationic, neutral and anionic) affected the overall reaction rate. Anionic antibiotic species are usually much more reactive (1-3 orders of magnitude greater) than cationic antibiotic species toward free available chlorine. Although OCl⁻ is a weaker oxidant than HOCl, chlorination of sulfadiazine, sulfamethoxazole, ciprofloxacin, norfloxacin, and trimethoprim with OCl⁻ became significant at pH > 7.5. The observed kinetics rate constants calculated from species-specific rate constants could accurately (0.91 removal in chlorination of activated sludge effluent with similar DOC and ammonia concentration to this study at a given pH value. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Chlorinated paraffins: properties, uses, and pollution potential

    National Research Council Canada - National Science Library

    Zitko, V; Arsenault, E

    1974-01-01

    The chemistry and applications of high molecular weight paraffins (C10-C30, 20-70% chlorine) are reviewed and data on solvent partitioning, thin layer chromatography and biodegredation of chlorinated paraffins are presented...

  13. Novel photosensitizers trigger rapid death of malignant human cells and rodent tumor transplants via lipid photodamage and membrane permeabilization.

    Directory of Open Access Journals (Sweden)

    Mikhail M Moisenovich

    Full Text Available BACKGROUND: Apoptotic cascades may frequently be impaired in tumor cells; therefore, the approaches to circumvent these obstacles emerge as important therapeutic modalities. METHODOLOGY/PRINCIPAL FINDINGS: Our novel derivatives of chlorin e(6, that is, its amide (compound 2 and boronated amide (compound 5 evoked no dark toxicity and demonstrated a significantly higher photosensitizing efficacy than chlorin e(6 against transplanted aggressive tumors such as B16 melanoma and M-1 sarcoma. Compound 5 showed superior therapeutic potency. Illumination with red light of mammalian tumor cells loaded with 0.1 µM of 5 caused rapid (within the initial minutes necrosis as determined by propidium iodide staining. The laser confocal microscopy-assisted analysis of cell death revealed the following order of events: prior to illumination, 5 accumulated in Golgi cysternae, endoplasmic reticulum and in some (but not all lysosomes. In response to light, the reactive oxygen species burst was concomitant with the drop of mitochondrial transmembrane electric potential, the dramatic changes of mitochondrial shape and the loss of integrity of mitochondria and lysosomes. Within 3-4 min post illumination, the plasma membrane became permeable for propidium iodide. Compounds 2 and 5 were one order of magnitude more potent than chlorin e(6 in photodamage of artificial liposomes monitored in a dye release assay. The latter effect depended on the content of non-saturated lipids; in liposomes consisting of saturated lipids no photodamage was detectable. The increased therapeutic efficacy of 5 compared with 2 was attributed to a striking difference in the ability of these photosensitizers to permeate through hydrophobic membrane interior as evidenced by measurements of voltage jump-induced relaxation of transmembrane current on planar lipid bilayers. CONCLUSIONS/SIGNIFICANCE: The multimembrane photodestruction and cell necrosis induced by photoactivation of 2 and 5 are

  14. Assessment of the chlorinated hydrocarbons residues contamination in edible mushrooms from the North-Eastern part of Poland.

    Science.gov (United States)

    Gałgowska, Michalina; Pietrzak-Fiećko, Renata; Felkner-Poźniakowska, Barbara

    2012-11-01

    The aim of the study was to determine the content of chlorinated hydrocarbon residues in edible mushrooms from the north-eastern part of Poland. Material consisted of two species of fungi: Xerocomus mushrooms (Xerocomus badius), Boletus mushrooms (Boletus edulis). The dried samples (cups and cut-up material) were extracted with Soxhlet method in order to obtain lipid substances. In the fat chlorinated hydrocarbons were determined by Ludwicki et al. (1996) method. The separation and quantitative determination of DDT, DDE, DDD and γ-HCH were conducted with the method of gas chromatography using an electron capture detector - ECD. In all tested samples the presence of γ-HCH, DDT and its metabolites (DDE, DDD) was detected. The higher content of γ-HCH was found in Xerocomus mushrooms (average 0.125 μg/kg of mushrooms); in the Boletus mushrooms -0.11 μg/kg of mushrooms. The content of ΣDDT in cups of Xerocomus mushrooms was more than 2-fold higher than in those of Boletus mushrooms (3.78:1.71 mg/kg of mushrooms). The opposite relationship was observed for cut-up material. The higher concentration of ΣDDT was found in Boletus mushrooms (2.26 mg/kg of mushrooms) while in Xerocomus mushrooms this content was 0.91 mg/kg of mushrooms. Despite the fact that chlorinated hydrocarbons were determined in all samples under study, their contents do not exceed acceptable levels indicating that the consumption of mushrooms does not pose a health risk to consumers from the organochlorine compounds.

  15. Colorectal cancers and chlorinated water

    Institute of Scientific and Technical Information of China (English)

    Ahmed Mahmoud El-Tawil

    2016-01-01

    Published reports have revealed increased risk of colorectal cancers in people exposed to chlorinated drinking water or chemical derivatives of chlorination. Oestrogen plays a dual positive functions for diminishing the possibilities of such risk by reducing the entrance, and increasing the excretion, of these chemicals. In addition, there are supplementary measures that could be employed in order to reduce this risk further, such as boiling the drinking water, revising the standard concentrations of calcium, magnesium and iron in the public drinking water and prescribing oestrogen in susceptible individuals. Hypo-methylation of genomic DNA could be used as a biological marker for screening for the potential development of colorectal cancers.

  16. Dandelion (Taraxacum officinale) flower extract suppresses both reactive oxygen species and nitric oxide and prevents lipid oxidation in vitro.

    Science.gov (United States)

    Hu, C; Kitts, D D

    2005-08-01

    Flavonoids and coumaric acid derivatives were identified from dandelion flower (Taraxacum officinale). Characteristics of chain-breaking antioxidants, such as extended lag phase and reduced propagation rate, were observed in oxidation of linoleic acid emulsion with the addition of dandelion flower extract (DFE). DFE suppressed both superoxide and hydroxyl radical, while the latter was further distinguished by both site-specific and non-specific hydroxyl radical inhibition. DPPH-radical-scavenging activity and a synergistic effect with alpha-tocopherol were attributed to the reducing activity derived from phenolic content of DFE. A significant (p < 0.05) and concentration-dependent, reduced nitric oxide production from acterial-lipopolysaccharide-stimulated mouse macrophage RAW264.7 cells was observed with the addition of DFE. Moreover, peroxyl-radical-induced intracellular oxidation of RAW264.7 cells was inhibited significantly (p < 0.05) by the addition of DFE over a range of concentrations. These results showed that the DFE possessed marked antioxidant activity in both biological and chemical models. Furthermore, the efficacy of DFE in inhibiting both reactive oxygen species and nitric oxide were attributed to its phenolic content.

  17. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    OpenAIRE

    Korich, D. G.; Mead, J R; Madore, M S; Sinclair, N A; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactiv...

  18. Disinfectants: Chlorine and chlorine dioxide. (Latest citations from the Life Sciences Collection database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    The bibliography contains citations concerning the antimicrobial properties of chlorine and chlorine dioxide. The use of chlorine for the inactivation of viruses, bacteria, and fungi in wastewater treatment plants is discussed, including the mode of action and factors influencing inactivation. The use of chlorine dioxide as an alternative to chlorine disinfection in swimming pools and water supplies, and possible adverse effects are also discussed. (Contains a minimum of 157 citations and includes a subject term index and title list.)

  19. Reactions of chlorine with inorganic and organic compounds during water treatment-Kinetics and mechanisms: a critical review.

    Science.gov (United States)

    Deborde, Marie; von Gunten, Urs

    2008-01-01

    Numerous inorganic and organic micropollutants can undergo reactions with chlorine. However, for certain compounds, the expected chlorine reactivity is low and only small modifications in the parent compound's structure are expected under typical water treatment conditions. To better understand/predict chlorine reactions with micropollutants, the kinetic and mechanistic information on chlorine reactivity available in literature was critically reviewed. For most micropollutants, HOCl is the major reactive chlorine species during chlorination processes. In the case of inorganic compounds, a fast reaction of ammonia, halides (Br(-) and I(-)), SO(3)(2-), CN(-), NO(2)(-), As(III) and Fe(II) with HOCl is reported (10(3)-10(9)M(-1)s(-1)) whereas low chlorine reaction rates with Mn(II) were shown in homogeneous systems. Chlorine reactivity usually results from an initial electrophilic attack of HOCl on inorganic compounds. In the case of organic compounds, second-order rate constants for chlorination vary over 10 orders of magnitude (i.e. organic compounds are possible pathways. However, from a kinetic point of view, usually only electrophilic attack is significant. Chlorine reactivity limited to particular sites (mainly amines, reduced sulfur moieties or activated aromatic systems) is commonly observed during chlorination processes and small modifications in the parent compound's structure are expected for the primary attack. Linear structure-activity relationships can be used to make predictions/estimates of the reactivity of functional groups based on structural analogy. Furthermore, comparison of chlorine to ozone reactivity towards aromatic compounds (electrophilic attack) shows a good correlation, with chlorine rate constants being about four orders of magnitude smaller than those for ozone.

  20. Chapter 21. chlorine dioxide

    Science.gov (United States)

    Submerging terminal leafy cuttings of Rhododendron L. 'Gumpo White' ('Gumpo White' azalea) in 50 °C water for 21 min was previously shown to eliminate binucleate Rhizoctonia species, the cause of azalea web blight, from plant tissues. Prior to considering commercial use of this practice, a better un...

  1. Tretinoin-loaded lipid-core nanocapsules decrease reactive oxygen species levels and improve bovine embryonic development during in vitro oocyte maturation.

    Science.gov (United States)

    Lucas, Caroline Gomes; Remião, Mariana Härter; Komninou, Eliza Rossi; Domingues, William Borges; Haas, Cristina; Leon, Priscila Marques Moura de; Campos, Vinicius Farias; Ourique, Aline; Guterres, Silvia S; Pohlmann, Adriana R; Basso, Andrea Cristina; Seixas, Fabiana Kömmling; Beck, Ruy Carlos Ruver; Collares, Tiago

    2015-12-01

    In vitro oocyte maturation (IVM) protocols can be improved by adding chemical supplements to the culture media. Tretinoin is considered an important retinoid in embryonic development and its association with lipid-core nanocapsules (TTN-LNC) represents an innovative way of improving its solubility, and chemical stability, and reducing its toxicity. The effects of supplementing IVM medium with TTN-LNC was evaluated by analyzing production of reactive oxygen species (ROS), S36-phosphorilated-p66Shc levels and caspase activity in early embryonic development, and expression of apoptosis and pluripotency genes in blastocysts. The lowest concentration tested (0.25μM) of TTN-LNC generated higher blastocyst rate, lower ROS production and S36-p66Shc amount. Additionally, expression of BAX and SHC1 were lower in both non-encapsulated tretinoin (TTN) and TTN-LNC-treated groups. Nanoencapsulation allowed the use of smaller concentrations of tretinoin to supplement IVM medium thus reducing toxic effects related with its use, decreasing ROS levels and apoptose frequency, and improving the blastocyst rates.

  2. New grape stems' isolated phenolic compounds modulate reactive oxygen species, glutathione, and lipid peroxidation in vitro: Combined formulations with vitamins C and E.

    Science.gov (United States)

    Queiroz, Marcelo; Oppolzer, David; Gouvinhas, Irene; Silva, Amélia M; Barros, Ana I R N A; Domínguez-Perles, Raúl

    2017-07-01

    The antioxidant potential of grape (Vitis vinífera L.) stems has been reported in the last decade although no identification of the individual compounds responsible for such action has been done. In this work, polyphenolic extract of grape stems was processed resorting to semi-preparative HPLC, allowing to obtain 5 purified polyphenols (caftaric acid, malvidin-3-O-glucoside, quercetin-3-O-glucuronide, mailvidin-3-O-(6-O-caffeoyl)-glucoside, and Σ-viniferin), which were fully characterized by HPLC-PDA-ESI-MS(n). Isolated compounds were featured on their radical scavenging capacity (DPPH and ABTS), cell viability, anti-inflammatory activity, and capacity to modulate the level of reactive oxygen species, glutathione, lipid peroxidation, and overall oxidative stress in a biological model (human keratinocytes) in vitro, under basal and oxidative conditions. The results obtained noticed the combinations malvidin-3-O-glucoside+Vitamin E and quercetin-3-O-glucuronide+vitamin C as the most effective, allowing to improve the capacity of complete extracts or individual compounds, and being candidates to be used in the development of new functional products. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Modeling and kinetic characterization of wastewater disinfection using chlorine and UV irradiation.

    Science.gov (United States)

    Mounaouer, Brahmi; Abdennaceur, Hassen

    2016-10-01

    Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine alone, ultraviolet radiation alone, and a combined disinfection process (chlorine-UV radiation). Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 11229, Salmonella typhi ATCC 14028, and Clostridium perfringens were selected to evaluate the efficiency of different disinfection processes. The aim of the present study was to characterize the kinetics of chlorine (as NaHOCl) consumption, to evaluate responses of these bacterial species to the chlorination, the ultraviolet (UV) radiation, and the chlorine/UV disinfection processes in secondary wastewater using a batch laboratory reactor. Another target of this work was to study the modeling of the kinetic of water disinfection by chlorination and/or UV irradiation. Two kinetic models (Chick-Watson and Hom) were tested as to ability to scale disinfection of these bacterial species by different ultraviolet and/or chlorine doses. The results of the kinetics of chlorine consumption showed that monochloramines and trichloramines were the most important forms of residual chlorine as compared to free chlorine and dichloramines. The kinetics of inactivation of all examined bacterial strains showed that the application of the model of Hom in its original form was not representative of this kinetics of inactivation. Modification of this model, considering an initial decline of bacteria during the contact of water with chlorine, improved the results of the model. By the same, results revealed that the involved processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of microorganisms and the use of nearly constant UV radiation intensity. In fact, the results have pointed out that the application of the Chick-Watson law is known to be inadequate to describe

  4. Kinetics and pathways of ibuprofen degradation by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Xiang, Yingying; Fang, Jingyun; Shang, Chii

    2016-03-01

    The UV/chlorine advanced oxidation process (AOP), which forms reactive species such as hydroxyl radicals (HO) and reactive chlorine species (RCS) such as chlorine atoms (Cl) and Cl2(-), is being considered as an alternative to the UV/H2O2 AOP for the degradation of emerging contaminants. This study investigated the kinetics and pathways of the degradation of a recalcitrant pharmaceutical and personal care product (PPCP)-ibuprofen (IBP)-by the UV/chlorine AOP. The degradation of IBP followed the pseudo first-order kinetics. The first-order rate constant was 3.3 times higher in the UV/chlorine AOP than in the UV/H2O2 AOP for a given chemical molar dosage at pH 6. The first-order rate constant decreased from 3.1 × 10(-3) s(-1) to 5.5 × 10(-4) s(-1) with increasing pH from 6 to 9. Both HO and RCS contributed to the degradation, and the contribution of RCS increased from 22% to 30% with increasing pH from 6 to 9. The degradation was initiated by HO-induced hydroxylation and Cl-induced chlorine substitution, and sustained through decarboxylation, demethylation, chlorination and ring cleavage to form more stable products. Significant amounts of chlorinated intermediates/byproducts were formed from the UV/chlorine AOP, and four chlorinated products were newly identified. The yield of total organic chlorine (TOCl) was 31.6 μM after 90% degradation of 50 μM IBP under the experimental conditions. The known disinfection by-products (DBPs) comprised 17.4% of the TOCl. The effects of water matrix in filtered drinking water on the degradation were not significant, demonstrating the practicality of the UV/chlorine AOP for the control of some refractory PPCPs. However, the toxicity of the chlorinated products should be further assessed.

  5. Environmental factors regulating soil organic matter chlorination

    Science.gov (United States)

    Svensson, Teresia; Montelius, Malin; Reyier, Henrik; Rietz, Karolina; Karlsson, Susanne; Lindberg, Cecilia; Andersson, Malin; Danielsson, Åsa; Bastviken, David

    2016-04-01

    Natural chlorination of organic matter is common in soils. Despite the widespread abundance of soil chlorinated soil organic matter (SOM), frequently exceeding soil chloride abundance in surface soils, and a common ability of microorganisms to produce chlorinated SOM, we lack fundamental knowledge about dominating processes and organisms responsible for the chlorination. To take one step towards resolving the terrestrial chlorine (Cl) puzzle, this study aims to analyse how environmental factors influence chlorination of SOM. Four factors were chosen for this study: soil moisture (W), nitrogen (N), chloride (Cl) and organic matter quality (C). These factors are all known to be important for soil processes. Laboratory incubations with 36Cl as a Cl tracer were performed in a two soil incubation experiments. It was found that addition of chloride and nitrogen seem to hamper the chlorination. For the C treatment, on the other hand, the results show that chlorination is enhanced by increased availability of labile organic matter (glucose and maltose). Even higher chlorination was observed when nitrogen and water were added in combination with labile organic matter. The effect that more labile organic matter strongly stimulated the chlorination rates was confirmed by the second separate experiment. These results indicate that chlorination was not primarily a way to cut refractory organic matter into digestible molecules, representing one previous hypothesis, but is related with microbial metabolism in other ways that will be further discussed in our presentation.

  6. Gas Phase Sulfur, Chlorine and Potassium Chemistry in Biomass Combustion

    DEFF Research Database (Denmark)

    Løj, Lusi Hindiyarti

    2007-01-01

    conditions. These trace species contained in the biomass structure will be released to the gas phase during combustion and contribute to the problems generated during the process. The investigation during this PhD project is done to stepwise improve the understanding in the chemistry and reduce...... the uncertainties. In the present work, the detailed kinetic model for gas phase sulfur, chlorine, alkali metal, and their interaction has been updated. The K/O/H/Cl chemistry, S chemistry, and their interaction can reasonably predict a range of experimental data. In general, understanding of the interaction......Gas Phase Sulfur, Chlorine and Alkali Metal Chemistry in Biomass Combustion Concern about aerosols formation, deposits, corrosion, and gaseous emissions during biomass combustion, especially straw, continues to be a driving force for investigation on S, Cl, K-containing species under combustions...

  7. Effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Chlorine content and position of chlorinated phenols have many significant effects on the reactivity of oxido-reduction. The effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate were evaluated through different kinetics studies. Since chlorine was an electron withdrawing atom, the substitution of chlorine on the aromatic ring decreased the oxidation rate constant by σ-electron withdrawing conductive effect; at the same time, the substitution of chlorine at ortho or para position on the aromatic ring increased the oxidation rate constant by π-electron donating conjugative effect, and the conjugative effect could counteract the negative impact of the conductive effect to some extent. On the other hand, the substitution of chlorine at ortho position on the aromatic ring decreased the oxidation rate constant by steric hindrance effect. The oxidation rate constants of phenol and chlorinated phenols studied decreased as follow order: 4-chlorophenol>2,4-dichlorophenol>phenol>2,6-dichlorophenol.

  8. Bioorthogonal chemical reporters for analyzing protein lipidation and lipid trafficking.

    Science.gov (United States)

    Hang, Howard C; Wilson, John P; Charron, Guillaume

    2011-09-20

    Protein lipidation and lipid trafficking control many key biological functions in all kingdoms of life. The discovery of diverse lipid species and their covalent attachment to many proteins has revealed a complex and regulated network of membranes and lipidated proteins that are central to fundamental aspects of physiology and human disease. Given the complexity of lipid trafficking and the protein targeting mechanisms involved with membrane lipids, precise and sensitive methods are needed to monitor and identify these hydrophobic molecules in bacteria, yeast, and higher eukaryotes. Although many analytical methods have been developed for characterizing membrane lipids and covalently modified proteins, traditional reagents and approaches have limited sensitivity, do not faithfully report on the lipids of interest, or are not readily accessible. The invention of bioorthogonal ligation reactions, such as the Staudinger ligation and azide-alkyne cycloadditions, has provided new tools to address these limitations, and their use has begun to yield fresh insight into the biology of protein lipidation and lipid trafficking. In this Account, we discuss how these new bioorthogonal ligation reactions and lipid chemical reporters afford new opportunities for exploring the biology of lipid-modified proteins and lipid trafficking. Lipid chemical reporters from our laboratory and several other research groups have enabled improved detection and large-scale proteomic analysis of fatty-acylated and prenylated proteins. For example, fatty acid and isoprenoid chemical reporters in conjunction with bioorthogonal ligation methods have circumvented the limited sensitivity and hazards of radioactive analogues, allowing rapid and robust fluorescent detection of lipidated proteins in all organisms tested. These chemical tools have revealed alterations in protein lipidation in different cellular states and are beginning to provide unique insights in mechanisms of regulation. Notably, the

  9. Ultrafast measurements of chlorine dioxide photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ludowise, P.D.

    1997-08-01

    Time-resolved mass spectrometry and time-resolved photoelectron spectroscopy are used to study the ultrafast photodissociation dynamics of chlorine dioxide, an important constituent in stratospheric ozone depletion. Chapter 1 introduces these pump/probe techniques, in which a femtosecond pump pulse excites a molecule to a dissociative state. At a later time, a second femtosecond probe pulse ionizes the molecule. The resulting mass and photoelectron spectra are acquired as a function of the delay between the pump and probe pulses, which follows the evolution of the molecule on the excited state. A comparison to other techniques used to study reaction dynamics is discussed. Chapter 2 includes a detailed description of the design and construction of the experimental apparatus, which consists of a femtosecond laser system, a molecular beam time-of-flight spectrometer, and a data acquisition system. The time-of-flight spectrometer is specifically designed to have a short flight distance to maximize the photoelectron collection efficiency without degrading the resolution, which is limited by the bandwidth of the femtosecond laser system. Typical performance of the apparatus is demonstrated in a study of the time-resolved photoelectron spectroscopy of nitric oxide. The results of the time-resolved mass spectrometry experiments of chlorine dioxide are presented in Chapter 3. Upon excitation to the A {sup 2}A{sub 2} state near 3.2 eV, the molecule dissociates through an indirect two-step mechanism. The direct dissociation channel has been predicted to be open, but is not observed. A quantum beat is observed in the OClO{sup +} species, which is described as a vibrational coherence of the optically prepared A {sup 2}A{sub 2} state. Chapter 4 presents the results of the time-resolved photoelectron experiments of chlorine dioxide. At short delay time, the quantum beat of the OClO{sup +} species is observed in the X {sup 1}A{sub 1} state of the ion. At infinite delay, the signal

  10. Clustering chlorine reactivity of haloacetic acid precursors in inland lakes.

    Science.gov (United States)

    Zeng, Teng; Arnold, William A

    2014-01-01

    Dissolved organic matter (DOM) represents the major pool of organic precursors for harmful disinfection byproducts, such as haloacetic acids (HAAs), formed during drinking water chlorination, but much of it remains molecularly uncharacterized. Knowledge of model precursors is thus a prerequisite for understanding the more complex whole water DOM. The utility of HAA formation potential data from model DOM precursors, however, is limited due to the lack of comparability to water samples. In this study, the formation kinetics of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two predominant HAA species, were delineated upon chlorination of seventeen model DOM precursors and sixty-eight inland lake water samples collected from the Upper Midwest region of the United States. Of particular interest was the finding that the DCAA and TCAA formation rate constants could be grouped into four statistically distinct clusters reflecting the core structural features of model DOM precursors (i.e., non-β-diketone aliphatics, β-diketone aliphatics, non-β-diketone phenolics, and β-diketone phenolics). A comparative approach built upon hierarchical cluster analysis was developed to gain further insight into the chlorine reactivity patterns of HAA precursors in inland lake waters as defined by the relative proximity to four model precursor clusters. This work highlights the potential for implementing an integrated kinetic-clustering approach to constrain the chlorine reactivity of DOM in source waters.

  11. Degradation of natural organic matter by UV/chlorine oxidation: Molecular decomposition, formation of oxidation byproducts and cytotoxicity.

    Science.gov (United States)

    Wang, Wen-Long; Zhang, Xue; Wu, Qian-Yuan; Du, Ye; Hu, Hong-Ying

    2017-11-01

    The degradation of natural organic matters (NOMs) by the combination of UV and chlorine (UV/chlorine) was investigated in this study. UV/chlorine oxidation can effectively degrade NOMs, with the degradation of chromophores (∼80%) and fluorophores (76.4-80.8%) being more efficient than that of DOC (15.1-18.6%). This effect was attributed to the chromophores and fluorophores (double bonds, aromatic groups and phenolic groups) being preferentially degraded by UV/chlorine oxidation, particularly reactive groups with high electron donating capacity. Radical species •OH and •Cl were generated during UV/chlorine oxidation, with the contribution of •OH 1.4 times as high as that of •Cl. The degradation kinetics of different molecular weight (MW) fractions suggests that UV/chlorine oxidation degrades high MW fractions into low MW fractions, with the degradation rates of high MW fractions (>3000 Da) 4.5 times of those of medium MW fractions (1000-3000 Da). In comparison with chlorination alone, UV/chlorine oxidation did not increase the formation (30 min) and formation potential (24 h) of trihalomethanes, but instead promoted the formation and formation potential of haloacetic acids and chloral hydrate. Adsorbable organic halogen (AOX) formed from UV/chlorine oxidation of NOM were 0.8 times higher than those formed from chlorination. Cytotoxicity studies indicated that the cytotoxicity of NOM increased after both chlorination and UV/chlorine oxidation, which may be due to the formation of AOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Examination of the kinetics of degradation of the antineoplastic drug 5-fluorouracil by chlorine and bromine.

    Science.gov (United States)

    Li, Wei; Tanumihardja, Jessica; Masuyama, Takaaki; Korshin, Gregory

    2015-01-23

    This study examined the degradation of the widely used antineoplastic drug 5-fluorouracil (5FU) by chlorine and bromine. 5FU was determined to interact readily with free chlorine and bromine but was stable in the presence of chloramine. The removal of 5FU followed a second-order kinetic pattern. Apparent rates (kapp) of 5FU removal by chlorine and bromine were strongly pH dependent and had maximum 14.8M(-1)s(-1) and 1.9×10(3)M(-1)s(-1)kapp values, respectively at pH 7. Modeling of the dependence of the kapp values vs. pH indicated the presence of a relatively acidic (pK 6.4 vs. 8.5 of 5FU per se) 5FU intermediate generated in the presence of halogen species. Spectrophotometric measurements confirmed the increased acidity of 5FU chlorination products and allowed proposing a degradation pathway of 5FU by chlorine. This pathway suggests that 5FU chlorination proceeds via chlorine incorporation at the 6th carbon in the heterocyclic ring of 5FU.

  13. Oxidative Dissolution of Silver Nanoparticles by Chlorine: Implications to Silver Nanoparticle Fate and Toxicity.

    Science.gov (United States)

    Garg, Shikha; Rong, Hongyan; Miller, Christopher J; Waite, T David

    2016-04-05

    The kinetics of oxidative dissolution of silver nanoparticles (AgNPs) by chlorine is investigated in this work, with results showing that AgNPs are oxidized in the presence of chlorine at a much faster rate than observed in the presence of dioxygen and/or hydrogen peroxide. The oxidation of AgNPs by chlorine occurs in air-saturated solution in stoichiometric amounts with 2 mol of AgNPs oxidized for each mole of chlorine added. Dioxygen plays an important role in OCl(-)-mediated AgNP oxidation, especially at lower OCl(-) concentrations, with the mechanism shifting from stoichiometric oxidation of AgNPs by OCl(-) in the presence of dioxygen to catalytic removal of OCl(-) by AgNPs in the absence of dioxygen. These results suggest that the presence of chlorine will mitigate AgNP toxicity by forming less-reactive AgCl(s) following AgNP oxidation, although the disinfection efficiency of OCl(-) may not be significantly impacted by the presence of AgNPs because a chlorine-containing species is formed on OCl(-) decay that has significant oxidizing capacity. Our results further suggest that the antibacterial efficacy of nanosilver particles embedded on fabrics may be negated when treated with detergents containing strong oxidants, such as chlorine.

  14. Chlorine Disinfection of Atypical Mycobacteria Isolated from a Water Distribution System

    Science.gov (United States)

    Le Dantec, Corinne; Duguet, Jean-Pierre; Montiel, Antoine; Dumoutier, Nadine; Dubrou, Sylvie; Vincent, Véronique

    2002-01-01

    We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C · t value (product of the disinfectant concentration and contact time) of 60 mg · min · liter−1, frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C · t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4°C to 25°C) and a decrease in pH result in better inactivation. PMID:11872446

  15. Transformation of humic acid and halogenated byproduct formation in UV-chlorine processes.

    Science.gov (United States)

    Li, Tong; Jiang, Yan; An, Xiaoqiang; Liu, Huijuan; Hu, Chun; Qu, Jiuhui

    2016-10-01

    The synergistic effect of ultraviolet light (UV) and chlorine on the structural transformation of Humic Acid (HA) and formation of chloro-disinfection byproducts (DBPs) in water were investigated, with chlorination as a reference. The transformation and mineralization of HA were enhanced upon co-exposure to UV and chlorine. Electron spin resonance (ESR) studies revealed that hydroxyl radical (OH) and chlorine radical (Cl) were predominant active species in a pH range from 4 to 7, while Cl dominated at pH 2 and pH higher than 7. The impact of different radicals on the transformation of HA was investigated by UV254, fluorescence and TOC measurements. OH were found to be responsible for the removal of chromophoric groups and mineralization of HA, while Cl mainly reacted with HA and intermediates from HA degradation. Due to the competitive and synergistic reaction of OH and Cl with HA, higher removal of HA and lower formation of chloro-DBPs appeared in UV-chlorine than chlorination, thus the combined UV-chlorine processes should be a promising method for water purification.

  16. SCREENING AND LIPID ANALYSES OF HIGH OLEAGINOUS CHLORELLA SPECIES%高产油小球藻的筛选及其油脂分析

    Institute of Scientific and Technical Information of China (English)

    徐进; 徐旭东; 方仙桃; 胡晗华

    2012-01-01

    Chlorella species which have strong adaptability distributes widely in various habitats, especially in the freshwater. Their assimilation product is mainly starch, but environmental stress can trigger lipid accumulation within the cells. The predominant fatty acids are C16 and C18 in Chlorella species, which are suitable feedstocks for biodiesel production. A number of Chlorella strains were isolated from fresh water of China, and their triacylglycerol contents were analyzed by thin layer chromatography. Out of 21 oleaginous Chlorella strains, a high oleaginous stain, NMX37N, was identified. It grew at temperatures from 15 to 35℃ but not at 40℃, and the optimum conditions, at 25 ℃ and 250 μmol photons/m2·s, it grew with a specific growth rate of 0.53/d. Batch culture experiments showed that the content of triacylglycerols in Chlorella sp. NMX37N increased with time and reached to the highest at the late stationary phase when the nitrate was exhausted. The total lipid content was 33% of dry cell weight when Chlorella sp. NMX37N grew under batch culture conditions for 40d. A two-step culture method, namely, transfer to the nitrogen deficiency condition at the late exponential phase (about 20d), gave a higher total lipid (36%) compared with the batch culture method. The main fatty acids (70%) in total lipids and triacylglycerols of Chlorella sp. NMX37N were C16 : 0 and C18 : 2. In addition, there were no long-chain fatty acids, such as C20, in Chlorella sp. NMX37N. The results indicated that the triacylglycerols in Chlorella sp. NMX37N may serve as excellent feedstocks for biodiesel production.%小球藻广泛分布于各种生境,特别是淡水环境中,适应性强.其同化产物主要是淀粉,但在环境胁迫条件下可显著积累中性脂,其脂肪酸类型主要为C16 和C18,适合作为生物柴油的原料.我们从中国部分地区水体中分离纯化到若干株小球藻,通过薄层层析比较分析了21 株产油小球藻的油脂含量,

  17. Comparative toxicity of insecticides to Choristoneura species (Lepidoptera: Tortricidae)

    Science.gov (United States)

    Jacqueline L. Robertson; Nancy L. Gillette; Barbara A. Lucas; Robert M. Russell; N.E. Savin

    1978-01-01

    Selected carbamate, chlorinated hydrocarbon, organophosphorous, and pyrethroid insecticides were tested on six Choristoneura species: conflictana (Walker), fumiferana (Clemens), lambertiana ponderosana Obraztsov, occidentalis Freeman, pinus Freeman, and...

  18. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  19. The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

    Science.gov (United States)

    Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

    2016-08-01

    Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

  20. Pathways of Lipid Metabolism in Marine Algae, Co-Expression Network, Bottlenecks and Candidate Genes for Enhanced Production of EPA and DHA in Species of Chromista

    Directory of Open Access Journals (Sweden)

    Alice Mühlroth

    2013-11-01

    Full Text Available The importance of n-3 long chain polyunsaturated fatty acids (LC-PUFAs for human health has received more focus the last decades, and the global consumption of n-3 LC-PUFA has increased. Seafood, the natural n-3 LC-PUFA source, is harvested beyond a sustainable capacity, and it is therefore imperative to develop alternative n-3 LC-PUFA sources for both eicosapentaenoic acid (EPA, 20:5n-3 and docosahexaenoic acid (DHA, 22:6n-3. Genera of algae such as Nannochloropsis, Schizochytrium, Isochrysis and Phaedactylum within the kingdom Chromista have received attention due to their ability to produce n-3 LC-PUFAs. Knowledge of LC-PUFA synthesis and its regulation in algae at the molecular level is fragmentary and represents a bottleneck for attempts to enhance the n-3 LC-PUFA levels for industrial production. In the present review, Phaeodactylum tricornutum has been used to exemplify the synthesis and compartmentalization of n-3 LC-PUFAs. Based on recent transcriptome data a co-expression network of 106 genes involved in lipid metabolism has been created. Together with recent molecular biological and metabolic studies, a model pathway for n-3 LC-PUFA synthesis in P. tricornutum has been proposed, and is compared to industrialized species of Chromista. Limitations of the n-3 LC-PUFA synthesis by enzymes such as thioesterases, elongases, acyl-CoA synthetases and acyltransferases are discussed and metabolic bottlenecks are hypothesized such as the supply of the acetyl-CoA and NADPH. A future industrialization will depend on optimization of chemical compositions and increased biomass production, which can be achieved by exploitation of the physiological potential, by selective breeding and by genetic engineering.

  1. iNOS null MRL+/+ mice show attenuation of trichloroethene-mediated autoimmunity: contribution of reactive nitrogen species and lipid-derived reactive aldehydes.

    Science.gov (United States)

    Wang, Gangduo; Wakamiya, Maki; Wang, Jianling; Ansari, G A S; Firoze Khan, M

    2015-12-01

    Earlier studies from our laboratory in MRL+/+ mice suggest that free radicals, especially overproduction of reactive nitrogen species (RNS) and lipid-derived reactive aldehydes (LDRAs), are associated with trichloroethene (TCE)-mediated autoimmune response. The current study was undertaken to further assess the contribution of RNS and LDRAs in TCE-mediated autoimmunity by using iNOS-null MRL+/+ mice. iNOS-null MRL+/+ mice were obtained by backcrossing iNOS-null mice (B6.129P2-Nos2(tm1Lau)/J) to MRL +/+ mice. Female MRL+/+ and iNOS-null MRL+/+ mice were given TCE (10 mmol/kg, i.p., every 4(th) day) for 6 weeks; their respective controls received corn oil only. TCE exposure led to significantly increased iNOS mRNA in livers, iNOS protein in livers and sera, increased nitrotyrosine (NT) formation in both livers and sera, induction of MDA-/HNE-protein adducts in livers and their respective antibodies in sera along with significant increases in serum antinuclear antibodies (ANA) and anti-dsDNA in MRL+/+ mice. Even though in iNOS-null MRL+/+ mice, the iNOS and NT levels were negligible in both TCE-treated and untreated groups, TCE treatment still led to significant increases in MDA-/HNE-protein adducts and their respective antibodies along with increases in serum ANA and anti-dsDNA compared to controls. Most remarkably, the increases in serum ANA and anti-dsDNA induced by TCE in the iNOS-null MRL+/+ mice were significantly less pronounced compared to that in MRL+/+ mice. Our results provide further evidence that both RNS and LDRAs contribute to TCE-induced autoimmunity in MRL+/+ mice, and iNOS deficiency attenuates this autoimmune response.

  2. Combined toxicity effects of chlorine, ammonia, and temperature on marine plankton. Progress report, February 1, 1975--September 15, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Ryther, J. H.; Goldman, J. C.

    1975-10-01

    Research on the combined effects of chlorine, ammonia, and temperature on marine plankton have been carried out for 7/sup 1///sub 2/ months. Continuous-flow bioassay units have been constructed for larval species, juvenile fish, and phytoplankton. A detailed study on lobster (Homarus americanus) larvae and other studies on killifish (Fundulus heteroclitus) larvae and juveniles, and juvenile scup (Stenotomus versicolor) and winter flounder (Pseudopleuronectes americanus) have been performed. Results to date indicate that there is an apparent and, as yet undetermined, chlorine demand of seawater; there is a differential toxic effect of chlorine and chloramines--lobsters were more sensitive to chloramines, whereas the fish species were more affected by free chlorine; respiration results indicate that significant stress occurs at toxicant levels below the onset of mortality, thus raising questions regarding the applicability of standard bioassay data; temperature elevation exerts a strong synergistic effect on chlorine-chloramine toxicity; and effects of exposure to halogen toxicity appear irreversible as revealed by persistent reductions in metabolic activity. It appears that chlorine toxicity to marine biota can occur even though chlorine residuals cannot be detected by current analytical techniques. These results support the findings of others that chlorine toxicity is a serious environmental pollutant. (auth)

  3. THREE-DIMENSIONAL MAPPING OF DIFFERENTIAL AMINO ACIDS OF HUMAN, MURINE, CANINE AND EQUINE TLR4/MD-2 RECEPTOR COMPLEXES CONFERRING ENDOTOXIC ACTIVATION BY LIPID A, ANTAGONISM BY ERITORAN AND SPECIES-DEPENDENT ACTIVITIES OF LIPID IVA IN THE MAMMALIAN LPS SENSOR SYSTEM

    Directory of Open Access Journals (Sweden)

    Thomas Scior

    2013-05-01

    Full Text Available A literature review concerning the unexpected species differences of the vertebrate innate immune response to lipid IVA was published in CSBJ prior to the present computational study to address the unpaired activity-sequence correlation of prototypic E. coli -type lipid A and its precursor lipid IVA regarding human, murine, equine and canine species. To this end, their sequences and structures of hitherto known Toll-like receptor 4 (TLR4 and myeloid differentiation factor 2 (MD-2 complexes were aligned and their differential side chain patterns studied. If required due to the lack of the corresponding X-ray crystallographic data, three-dimensional models of TLR4/MD-2/ligand complexes were generated using mono and dimeric crystal structures as templates and in silico docking of the prototypic ligands lipid A, lipid IVA and Eritoran. All differential amino acids were mapped to pinpoint species dependency on an atomic scale, i.e. the possible concert of mechanistically relevant side chains. In its most abstract and general form the three-dimensional (3D- models devise a triangular interface or “wedge” where molecular interactions between TLR4, MD-2 and ligand itself take place. This study identifies two areas in the wedge related to either agonism or antagonism reflecting why ligands like lipid IVA can possess a species dependent dual activity. Lipid IVA represents an imperfect (underacylated and backbone-flipped, low affinity ligand of mammalian TLR4/MD-2 complexes. Its specific but weak antagonistic activity in the human system is in particular due to the loss of phosphate attraction in the wedge-shaped region conferred by nonhomologous residue changes when compared to crystal and modeled structures of the corresponding murine and equine TLR4/MD-2 complexes. The counter-TLR4/MD-2 unit was also taken into account since agonist-mediated dimerization in a defined m-shaped complex composed of two TLR4/MD-2/agonist subunits triggers intracellular

  4. Three-dimensional mapping of differential amino acids of human, murine, canine and equine TLR4/MD-2 receptor complexes conferring endotoxic activation by lipid A, antagonism by Eritoran and species-dependent activities of Lipid IVA in the mammalian LPS sensor system.

    Science.gov (United States)

    Scior, Thomas; Lozano-Aponte, Jorge; Figueroa-Vazquez, Vianihuini; Yunes-Rojas, Julian A; Zähringer, Ulrich; Alexander, Christian

    2013-01-01

    A literature review concerning the unexpected species differences of the vertebrate innate immune response to lipid IVA was published in CSBJ prior to the present computational study to address the unpaired activity-sequence correlation of prototypic E. coli -type lipid A and its precursor lipid IVA regarding human, murine, equine and canine species. To this end, their sequences and structures of hitherto known Toll-like receptor 4 (TLR4) and myeloid differentiation factor 2 (MD-2) complexes were aligned and their differential side chain patterns studied. If required due to the lack of the corresponding X-ray crystallographic data, three-dimensional models of TLR4/MD-2/ligand complexes were generated using mono and dimeric crystal structures as templates and in silico docking of the prototypic ligands lipid A, lipid IVA and Eritoran. All differential amino acids were mapped to pinpoint species dependency on an atomic scale, i.e. the possible concert of mechanistically relevant side chains. In its most abstract and general form the three-dimensional (3D-) models devise a triangular interface or "wedge" where molecular interactions between TLR4, MD-2 and ligand itself take place. This study identifies two areas in the wedge related to either agonism or antagonism reflecting why ligands like lipid IVA can possess a species dependent dual activity. Lipid IVA represents an imperfect (underacylated and backbone-flipped), low affinity ligand of mammalian TLR4/MD-2 complexes. Its specific but weak antagonistic activity in the human system is in particular due to the loss of phosphate attraction in the wedge-shaped region conferred by nonhomologous residue changes when compared to crystal and modeled structures of the corresponding murine and equine TLR4/MD-2 complexes. The counter-TLR4/MD-2 unit was also taken into account since agonist-mediated dimerization in a defined m-shaped complex composed of two TLR4/MD-2/agonist subunits triggers intracellular signaling during the

  5. The potential feasibility of chlorinic photosynthesis on exoplanets.

    Science.gov (United States)

    Haas, Johnson R

    2010-11-01

    The modern search for life-bearing exoplanets emphasizes the potential detection of O(2) and O(3) absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl(-) to form halocarbon or dihalogen products, coupled with CO(2) assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.

  6. Catalytic hydrogen-chlorine exchange between chlorinated hydrocarbons under oxygen-free conditions

    NARCIS (Netherlands)

    van der Heijden, A.W.A.M.; Podkolzin, S.G.; Jones, M.E.; Bitter, J.H.; Weckhuysen, B.M.

    2008-01-01

    Chlorinated hydrocarbons (CHCs) remain important industrial chemical intermediates and solvents, especially for the exploration of the potential of La-based materials for the conversion of chlorinated waste compounds.[1] The production of industrially important CHCs frequently occurs with concurrent

  7. Efficacy of chlorine dioxide mouthwash against halitosis

    Science.gov (United States)

    Bestari, M. D.; Sunarto, H.; Kemal, Y.

    2017-08-01

    To ascertain the effectiveness of using chlorine dioxide mouthwash in addressing halitosis. Forty people were divided equally into the test group (required to gargle with mouthwash containing chlorine dioxide) and the control group (required to gargle with aquadest). The volatile sulfur compound (VSC) and organoleptic scores were measured before gargling and 30 min, 2 h, 4 h, and 6 h after. The Wilcoxon test analysis showed a significant difference (pChlorine dioxide mouthwash is effective in addressing halitosis.

  8. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  9. The chlorination of cyclopentanone and cyclohexanone

    NARCIS (Netherlands)

    Maatman, Hendrik

    1980-01-01

    In this thesis the results of an investigation of the chlorination of cyclopentanone and cyclohexanone in the solvent carbontetrachloride and catalyzed by hydrogen chloride are described. ... Zie: Summary

  10. High resolution spectrophotometry for identification of chlorine dioxide in concentrated chlorine solutions.

    Science.gov (United States)

    Gauw, R D; Emmert, G L; Bubnis, B; Gordon, G

    1999-12-06

    Electrolyzed salt brine generators hold great promise for water disinfection in small communities and remote locations. Electrolysis cell liquors have been reported to contain chlorine, chlorine dioxide and ozone. High resolution spectrophotometry was used to observe the presence (or absence) of a unique spectral absorbance pattern present in solutions containing 1-2 mg/l chlorine dioxide.

  11. Depletion of chlorine into HCl ice in a protostellar core

    CERN Document Server

    Kama, M; Lopez-Sepulcre, A; Wakelam, V; Dominik, C; Ceccarelli, C; Lanza, M; Lique, F; Ochsendorf, B B; Lis, D C; Caballero, R N; Tielens, A G G M

    2014-01-01

    The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances $<10^{-5}$ has not yet been well studied. Our aim here is to study the depletion of chlorine in the protostellar core, OMC-2 FIR 4. We observed transitions of HCl and H2Cl+ towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H$_{2}$ hyperfine collisional excitation rate coefficients. A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9e-11, a factor of only 0.001 that of volatile elemental chlorine. The H2Cl+ lines are detected in absorption and trace a tenuous fo...

  12. Phytoscreening of BTEX and chlorinated solvents by tree coring

    DEFF Research Database (Denmark)

    Nielsen, Mette Algreen; Broholm, Mette Martina; Trapp, Stefan

    Background/Objectives. Site characterization is often time consuming and a financial burden for the site owners, which raises a demand for rapid and inexpensive screening methods. Tree coring is a phytoscreening method useful for detection of contamination with organic compounds. The method takes......(s). The measured concentrations are also compared to concentrations detected in soil and/or groundwater. Furthermore, the two screening technologies Tree coring and Soil air sampling have been compared to evaluate the feasibility of the tree coring method. Results/Lessons Learned. The method of tree coring can...... detect contamination with BTEX and chlorinated solvents in the shallow subsurface. The uptake of BTEX into trees varies to a greater extent with the site conditions and tree species than chlorinated solvents, which lead to greater uncertainty. Tree coring is semi-quantitative, low...

  13. Chlorine dioxide and by-products in water distribution systems

    OpenAIRE

    Ferreira, Francisco Cardoso

    1991-01-01

    Chlorine dioxide is used as both a pre-oxidant and/or a post-disinfectant in several water treatment plants in the United States. Chlorine dioxide is associated with its byproducts chlorite and chlorate. Chlorine dioxide, chlorine, chlori te and chlorate were sampled in four distribution systems where chlorine dioxide is used for disinfection purposes: Charleston, WV, Columbus, GA, New Castle, PA, and Skagit, WA. The fate of chlorine dioxide and its by-products in dist...

  14. Natural chlorine and fluorine in the atmosphere, water and precipitation

    Science.gov (United States)

    Friend, James P.

    1990-01-01

    The geochemical cycles of chlorine and fluorine are surveyed and summarized as framework for the understanding of the global natural abundances of these species in the atmosphere, water, and precipitation. In the cycles the fluxes into and out of the atmosphere can be balanced within the limits of our knowledge of the natural sources and sinks. Sea salt from the ocean surfaces represent the predominant portion of the source of chlorine. It is also an important source of atmospheric fluorine, but volcanoes are likely to be more important fluorine sources. Dry deposition of sea salt returns about 85 percent of the salt released there. Precipitation removes the remainder. Most of the sea salt materials are considered to be cyclic, moving through sea spray over the oceans and either directly back to the oceans or deposited dry and in precipitation on land, whence it runs off into rivers and streams and returns to the oceans. Most of the natural chlorine in the atmosphere is in the form of particulate chloride ion with lesser amounts as gaseous inorganic chloride and methyl chloride vapor. Fluorine is emitted from volcanoes primarily as HF. It is possible that HF may be released directly form the ocean surface but this has not been confirmed by observation. HCl and most likely HF gases are released into the atmosphere by sea salt aerosols. The mechanism for the release is likely to be the provision of protons from the so-called excess sulfate and HNO3. Sea salt aerosol contains fluorine as F(-), MgF(+), CaF(+), and NaF. The concentrations of the various species of chlorine and fluorine that characterize primarily natural, unpolluted atmospheres are summarized in tables and are discussed in relation to their fluxes through the geochemical cycle.

  15. Inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine.

    OpenAIRE

    Berman, D; Hoff, J C

    1984-01-01

    The kinetics of inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine were studied at 5 degrees C with a purified preparation of single virions and a preparation of cell-associated virions. Inactivation of the virus preparations with chlorine and chlorine dioxide was studied at pH 6 and 10. The monochloramine studies were done at pH 8. With 0.5 mg of chlorine per liter at pH 6, more than 4 logs (99.99%) of the single virions were inactivated in less than 15 s...

  16. The photoreactivity of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Vaida, V. [Univ. of Colorado, Boulder, CO (United States); Simon, J.D. [Univ. of California, San Diego, La Jolla, CA (United States)

    1995-06-09

    Determining the detailed photoreactivity of radicals that are of importance in atmospheric processes requires information from both laboratory and field measurements and theoretical calculations. Laboratory experiments and quantum calculations have been used to develop a comprehensive understanding of the photoreactivity of chlorine dioxide (OClO). The photoreactivity is strongly dependent on the medium (gas phase, liquid solution, or cryogenic matrix). These data reveal details of the complex chemistry of OClO. The potential role of this radical in stratospheric ozone depletion is discussed in accord with these laboratory measurements. 53 refs., 4 figs.

  17. Bank security dye packs: synthesis, isolation, and characterization of chlorinated products of bleached 1-(methylamino)anthraquinone.

    Science.gov (United States)

    Egan, James M; Rickenbach, Michael; Mooney, Kim E; Palenik, Chris S; Golombeck, Rebecca; Mueller, Karl T

    2006-11-01

    Banknote evidence is often submitted after a suspect has attempted to disguise or remove red dye stain that has been released because of an anti-theft device that activates after banknotes have been unlawfully removed from bank premises. Three chlorinated compounds have been synthesized as forensic chemical standards to indicate bank security dye bleaching as a suspect's intentional method for masking a robbery involving dye pack release on banknotes. A novel, facile synthetic method to provide three chlorinated derivatives of 1-(methylamino)anthraquinone (MAAQ) is presented. The synthetic route involved Ultra Clorox bleach as the chlorine source, iron chloride as the catalyst, and MAAQ as the starting material and resulted in a three-component product mixture. Two mono-chlorinated isomers (2-chloro-1-(methylamino)anthraquinone and 4-chloro-1-(methylamino)anthraquinone) and one di-chlorinated compound (2,4-dichloro-1-(methylamino)anthraquinone) of the MAAQ parent molecule were detected by gas chromatography mass spectrometry (GC-MS), and subsequently isolated by liquid chromatography (LC) with postcolumn fraction collection. Although GC-MS is sensitive enough to detect all of the chlorinated products, it is not definitive enough to identify the structural isomers. Liquid-state nuclear magnetic resonance (NMR) spectroscopy was utilized to elucidate structurally the ortho- and para-mono-chlorinated isomers once enough material was properly isolated. A reaction mechanism involving iron is proposed to explain the presence of chlorinated MAAQ species on stolen banknotes after attempted bleaching.

  18. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability

    Energy Technology Data Exchange (ETDEWEB)

    Korich, D.G.; Mead, J.R.; Madore, M.S.; Sinclair, N.A.; Sterling, C.R. (Univ. of Arizona, Tucson (USA))

    1990-05-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water.

  19. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    Science.gov (United States)

    Korich, D G; Mead, J R; Madore, M S; Sinclair, N A; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water. PMID:2339894

  20. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  1. Mutagenic compounds from chlorination of humic substances

    Science.gov (United States)

    Holmbom, Bjarne

    Chlorination of natural humic substances, as well as of lignin, produces a myriad of non-chlorinated and chlorinated compounds. The identification of an important class of strongly mutagenic compounds is reviewed. The most important Ames mutagen in chlorinated drinking waters of various origin is the compound 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone ("MX"). This compound occurs at neutral pH in the acyclic form, i.e. in the form of Z-2-chloro-3-(dichloromethyl)-4-oxobutenoic acid. Its E-isomer (E-MX) is present in chlorinated drinking waters at a similar concentration, but is less mutagenic in Ames test. Both oxidised and reduced forms of MX and E-MX are also present in chlorinated waters. The present knowledge of the chemistry and toxicology of these mutagens is examined. The formation and possible elimination of the chlorination mutagens is discussed. The need of understanding the mechanisms of formation of these mutagens from humic substances during drinking water chlorination is emphasized.

  2. Chlorination products: emerging links with allergic diseases.

    Science.gov (United States)

    Bernard, A

    2007-01-01

    Exposure of the human population to chlorination products has considerably increased during the 20(th) century especially after the 1960s with the development of public and leisure pools. The present article summarizes current knowledge regarding the human exposure to chlorination products and reviews studies suggesting that these chemicals might be involved in the development or exacerbation of allergic diseases. Populations regularly in contact with chlorination products such as swimmers, lifeguards or workers using chlorine as cleaning or bleaching agent show increased risks of allergic diseases or of respiratory disorders frequently associated with allergy. Experimental evidence suggests that chlorination products promote allergic sensitization by compromising the permeability or the immunoregulatory function of epithelial barriers. These findings led to the chlorine hypothesis proposing that the rise of allergic diseases could result less from the declining exposure to microbial agents (the hygiene hypothesis) than from the increasing and largely uncontrolled exposure to products of chlorination, the most widely used method to achieve hygiene in the developed world. Giving the increasing popularity of water recreational areas, there is an obvious need to assess the effects of chlorine-based oxidants on human health and their possible implication in the epidemic of allergic diseases.

  3. Comparative evaluation of effects of ozonated and chlorinated thermal discharges on estuarine and fresh water organisms. First quarterly progress report, April 1979

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, C.R.; DelMonaco, J.L.; Singletary, J.H.; Sugam, R.J.; Meldrim, J.W.; Holmstrom, E.R.; Balog, G.F.

    1979-01-01

    The biological evaluation program incorporates three types of experimental tests: acute (96 hour) toxicity studies; behavioral (avoidance) response studies; and physiological (cough) response studies. In addition, specimens used in testing are examined for physical damage resulting from exposure to chlorine or ozoen. The objective of the acute (96 hour) toxicity study is to determine the respective lethal levels (LC/sub 50/) of chlorinated and ozonated waters. The objective of the behavioral (avoidance) response study is to determine what (if any) concentrations of ozone and of chlorine will be avoided. The objective of physiological (cough) response study is to determine what concentrations of ozone and of chlorine are physiologically detected. Ozonated and chlorinated waters were evaluated in all studies for both the addition of increased temperature and without it. Results indicate that ozone is less toxic than chlorine under the test conditions used. The lethal levels vary according to species of water quality measurements at Bergen Generating Station, New York are tabulated. (JBG)

  4. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berztiss, D.; Hennesen, K.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1998-12-31

    In contrast to internal oxidation, sulfidation and carburization, very little information is available regarding internal chlorination, especially diffusion of chlorine in metallic alloys. This paper describes results of experiments on Ni-Cr alloys (<10 wt% Cr) exposed in an atmosphere containing radioactive HCl. The diffusion of chlorine in the alloy can be determined by measurement of residual {beta}-activity from the sample surface. Successively thin layers (0.5-10 {mu}m) of the alloy were removed by lapping and the surface activity was measured to obtain a depth profile. Both single and polycrystalline materials were tested. Through this work it should be determined if there is in fact solubility and diffusion of chlorine in Ni-based alloys as some authors have proposed or if the ingress of chlorine is mainly a grain boundary phenomenon. (orig.)

  5. Chloride and organic chlorine in forest soils: storage, residence times, and influence of ecological conditions.

    Science.gov (United States)

    Redon, Paul-Olivier; Abdelouas, Abdesselam; Bastviken, David; Cecchini, Sébastien; Nicolas, Manuel; Thiry, Yves

    2011-09-01

    Recent studies have shown that extensive chlorination of natural organic matter significantly affects chlorine (Cl) residence time in soils. This natural biogeochemical process must be considered when developing the conceptual models used as the basis for safety assessments regarding the potential health impacts of 36-chlorine released from present and planned radioactive waste disposal facilities. In this study, we surveyed 51 French forested areas to determine the variability in chlorine speciation and storage in soils. Concentrations of total chlorine (Cl(tot)) and organic chlorine (Cl(org)) were determined in litterfall, forest floor and mineral soil samples. Cl(org) constituted 11-100% of Cl(tot), with the highest concentrations being found in the humus layer (34-689 mg Cl(org) kg(-1)). In terms of areal storage (53 - 400 kg Cl(org) ha(-1)) the mineral soil dominated due to its greater thickness (40 cm). Cl(org) concentrations and estimated retention of organochlorine in the humus layer were correlated with Cl input, total Cl concentration, organic carbon content, soil pH and the dominant tree species. Cl(org) concentration in mineral soil was not significantly influenced by the studied environmental factors, however increasing Cl:C ratios with depth could indicate selective preservation of chlorinated organic molecules. Litterfall contributions of Cl were significant but generally minor compared to other fluxes and stocks. Assuming steady-state conditions, known annual wet deposition and measured inventories in soil, the theoretical average residence time calculated for total chlorine (inorganic (Cl(in)) and organic) was 5-fold higher than that estimated for Cl(in) alone. Consideration of the Cl(org) pool is therefore clearly important in studies of overall Cl cycling in terrestrial ecosystems.

  6. Lipid somersaults

    DEFF Research Database (Denmark)

    Günther-Pomorski, Thomas; Menon, Anant K.

    2016-01-01

    Membrane lipids diffuse rapidly in the plane of the membrane but their ability to flip spontaneously across a membrane bilayer is hampered by a significant energy barrier. Thus spontaneous flip-flop of polar lipids across membranes is very slow, even though it must occur rapidly to support divers...

  7. Comparative evaluation of 13 yeast species in the Yarrowia clade on lignocellulosic biomass hydrolysate and genetic engineering of inhibitor tolerant strains for lipid and biofuel production

    Science.gov (United States)

    Yarrowia lipolytica is an oleaginous yeast that has garnered interest for commercial production of single cell oil and other fatty acid-derived chemicals because of its GRAS status and genetic tractability. Three recent peer-reviewed studies have highlighted the possibility of lipid production by th...

  8. Formation and distribution of disinfection by-products during chlorine disinfection in the presence of bromide ion

    Institute of Scientific and Technical Information of China (English)

    LI Bo; QU JiuHui; LIU HuiJuan; ZHAO Xu

    2008-01-01

    The influences of contact time and pH value on the formation and distribution of four species of triha-lomethanes and five species of haloacetic acids during chlorination in the presence of bromine were investigated. Results showed that the distribution of molar fraction of trihalomethanes varied with contact time due to the change of bromide ion concentration during chlorination. Most of the triha-lomethanes comprising bromine-containing species and the favored products of the haloacetic acids were chlorine-containing species after 24 h of chlorination. The extent of bromine incorporation in tri-halomethanes and haloacetic acids both decreased with time. The contact time also had influence on the formation rate of different species of haloacetic acids. The formation and distribution of triha-lomethanes and haloacetic acids strongly depended on the chlorination pH value. All of the triha-lomethanes species formation increased with the increase of pH value except the bromoform that had not been detected. The molar fraction of bromodichloromethane and dibromochloromethane contain-ing bromine increased with pH value while chloroform without bromine decreased. Under the pH range studied in this experiment, the predominant haloacetic acids species were trichloroacetic acid and dichloroacetic acid which all decreased with the increase of pH value and the level of TCAA was higher than that of DCAA.

  9. Enumeration and characterization of standard plate count bacteria in chlorinated and raw water supplies.

    Science.gov (United States)

    LeChevallier, M W; Seidler, R J; Evans, T M

    1980-11-01

    Nearly 700 standard plate count (SPC) bacteria were isolated from drinking water and untreated surface water and identified according to a scheme developed to permit the rapid, simple classification of microorganisms to genus, species, or group. Actinomycetes and Aeromonas species were the two most common groups of SPC bacteria in chlorinated distribution water. Aeromonas spp. and Enterobacter agglomerans were the two most common groups of SPC bacteria in raw water. Identification of bacterial populations before and after contact with chlorine (1 to 2 mg/liter) for 1 h revealed that chlorination selected for gram-positive bacteria. Water that contained high densities of bacteria known to be antagonistic to coliforms had low coliform isolation rates. The membrane filtration technique for enumerating SPC bacteria recovered significantly higher numbers (P standard pour plate technique.

  10. Control of modiolid mussels in cooling water systems by continuous chlorination.

    Science.gov (United States)

    Rajagopal, S; Venugopalan, V P; van der Velde, G; Jenner, H A

    2006-08-01

    Modiolid mussels such as Modiolus philippinarum and Modiolus metcalfei constitute a numerically significant group in fouling communities, especially in tropical and subtropical industrial cooling water systems. Nevertheless, there are hardly any published reports on the tolerance of these species to chlorination or biofouling control measures, This article provides data on the mortality pattern (LT(50) and LT(100)) and physiological activities (oxygen consumption, filtration rate, foot activity, and byssus thread production) of different size groups of M. philippinarum (7- to 30-mm shell lengths) and M. metcalfei (6- to 26-mm shell lengths) exposed to different concentrations of residual chlorine (0.25, 0.50, 0.75, and 1.00 mg/L for sublethal responses; 1, 2, 3, and 5 mg/L for mortality). It is shown that exposure time for 100% mortality of M. philippinarum and M. metcalfei significantly decreased with increasing residual chlorine concentration. For example, 30-mm size group M. philippinarum exposed to 1 mg/L chlorine residual took 402 h to reach 100% mortality, whereas those exposed to 5 mg/L chlorine took 108 h. Among the two mussels, M. philippinarum showed slightly higher tolerance (9-20%) to chlorine when compared to M. metcalfei. The effect of mussel size on mortality of M. philippinarum was significant, with the larger size group mussels showing greater resistance than smaller ones. However, in M. metcalfei, size of the mussel does not seem to be a determinant of its chlorine tolerance. All size groups of M. philippinarum and M. metcalfei showed progressive reduction in physiological activities (oxygen consumption, filtration rate, foot activity index, and byssus thread production) when chlorine residuals gradually increased from 0 to 1 mg/L. Reduction in physiological activities was strongly correlated with chlorine concentration. A comparison of present data with data available for other coexisting mussel species suggests that M. philippinarum and M

  11. Diffusion of chlorin-p6 across phosphatidyl choline liposome bilayer probed by second harmonic generation.

    Science.gov (United States)

    Saini, R K; Dube, A; Gupta, P K; Das, K

    2012-04-12

    We have investigated the diffusion of the photosensitizer Chlorin-p(6) (Cp(6)) across a egg lecithin lipid bilayer at different pH by the Second Harmonic Generation (SHG) method. Cp(6) has three ionizable carboxylic acid groups, and consequently, neutral and several ionic forms of Cp(6) are expected to be present in the pH range 3-8. The absorption spectra of Cp(6) get considerably modified in the presence of liposomes as the pH is decreased indicating that the drug liposome binding is pH dependent. The first pK(a) of interconversion (D-C) has been identified at pH ~7.0 by fluorescence measurement in an earlier work. In this work, the second pK(a) of interconversion (C-B) has been identified at pH ~4.8 by the hyper-Rayleigh scattering method. At acidic pH (3, 4, and 5), where species A, B, and C are dominant, the addition of liposomes to a Cp(6) solution generates an instantaneous rise (less than 1 s) in the second harmonic (SH) signal followed by decays whose time constants ranged from ten to hundreds of seconds. The instantaneous rise is attributed to the adsorption of Cp(6) to the outer lipid bilayer, and the decay is attributed to the diffusion of the neutral and charged (A and B) species of the drug. The observed fast and slow time constants for diffusion in the pH range 3-5 are attributed to the neutral (A) and ionic form (B) of Cp(6), respectively. At pH 6, the intensity of the generated SH signals on the addition of liposome reduced, and at physiological pH, it was too weak to be detected. These results are consistent with previous studies that show that the interaction between Cp(6) and egg-PC liposomes is pH dependent. At lower pH due to the presence of the hydrophobic species (A and B) of Cp(6), its interaction with liposomes is strong, and at higher pH, the abundance of the negatively charged hydrophilic species (C and D) decreases the interaction with the like charged liposomes. We have also studied the effect of increasing the bilayer rigidity by

  12. Chlorination of Wastewater, Manual of Practice No. 4.

    Science.gov (United States)

    Water Pollution Control Federation, Washington, DC.

    This manual reviews chlorination practices in the treatment and disposal of wastes from the earliest known applications. The application of chlorination for various purposes is described but no attempt has been made to compare chlorination with other methods. Included are chapters on the development and practice of wastewater chlorination,…

  13. Electron affinity of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, L.M.; Pentecost, T.; Koppenol, W.H. (Louisiana State Univ., Baton Rouge (USA))

    1989-12-14

    The flowing afterglow technique was used to determine the electron affinity of chlorine dioxide. A value of 2.37 {plus minus} 0.10 eV was found by bracketing between the electron affinities of HS* and SF{sub 4} as a lower limit and that of NO{sub 2} as an upper limit. This value is in excellent agreement with 2.32 eV predicted from a simple thermodynamic cycle involving the reduction potential of the ClO{sub 2}/ClO{sub 2}{sup {minus}} couple and a Gibbs hydration energy identical with that of SO{sub 2}{sup {sm bullet}{minus}}.

  14. Phosphate valorization by dry chlorination route

    OpenAIRE

    Kanari N.; Menad N.; Diot F.; Allain E.; Yvon J.

    2016-01-01

    International audience; This work deals with the extraction of phosphorus chlorinated compounds from phosphate materials using chlorination with gaseous chlorine. An industrial sample of dicalcium phosphate dihydrate, after transformation into calcium pyrophosphate (Ca 2 P 2 O 7), is subjected to reactions with Cl 2 +CO+N 2 and Cl 2 +C+N 2 at temperatures ranging from 625 to 950 °C using boat experiments. Gathering results of the thermodynamic predictions and TG/DT analysis with those of SEM ...

  15. A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

    OpenAIRE

    Taylor, G. R.; Butler, M.

    1982-01-01

    Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the ...

  16. A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

    OpenAIRE

    Taylor, G R; Butler, M.

    1982-01-01

    Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the ...

  17. The critical role of lipid rafts nanodomains in the cross-talk between calcium and reactive oxygen and nitrogen species in cerebellar granule neurons apoptosis by extracellular potassium deprivation

    Directory of Open Access Journals (Sweden)

    Carlos Gutierrez-Merino

    2016-01-01

    Full Text Available The apoptosis of cerebellar granule neurons (CGN induced by low-potassium in serum free medium in vitro has become a widely used model for neuronal apoptosis during in vivo brain development. In this review we shall summarize first the basic features of this model for neuronal apoptosis. Next, we shall focus on the L-type calcium channels (LTCC inactivation as the primary pro-apoptotic signal in low K+-induced CGN death. This apoptotic process can be split into two major and sequential cellular signaling phases: one reversible phase that offers a temporal window for therapeutic interventions to prevent neuronal death, and an irreversible later phase. Therefore, we shall comment next the critical role of reactive oxygen species (ROS production and major ROS sources triggering the entry of CGN in the irreversible stages of low K+-induced apoptosis. Then, we shall present the experimental evidences showing clustering of LTCC and ROS producing enzymes in plasma membrane lipid rafts of CGN matured in vitro, which have opened new perspectives for cell signaling in the early and reversible phase of this apoptosis. The role of lipid rafts nanodomains as fast response calcium/nitric oxide transducers of the switch of CGN to low K+ medium will be discussed next. The two major conclusions drawn from this review are: (1 deregulation of the pool of cytochrome b5 reductase associated to plasma membrane-lipid rafts, at least in part due to overexpression of cytochrome b5, can account for the critical superoxide anion overshot which triggers the entry in the irreversible phase of low K+ apoptosis of CGN, and (2 LTCC inactivation is rapidly transduced by lipid rafts nanodomains into a large drop of cytosolic calcium, a switch-off of nitric oxide production and subsequent inactivation of survival signaling pathways dependent on the activity of CaMKII, PKA and Akt/PKB kinases.

  18. Ozone depletion and chlorine loading potentials

    Science.gov (United States)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  19. Behavior of chlorine during coal pyrolysis

    Science.gov (United States)

    Shao, D.; Hutchinson, E.J.; Cao, H.; Pan, W.-P.; Chou, C.-L.

    1994-01-01

    The behavior of chlorine in Illinois coals during pyrolysis was evaluated by combined thermo-gravimetry-Fourier transform infrared spectroscopy-ion chromatography (TG-FTIR-IC) techniques. It was found that more than 90% of chlorine in Illinois coals (IBC-103, 105, 106, and 109) was liberated as HCl gas during pyrolysis from 300 to 600??C, with the rate reaching a maximum at 440 ??C. Similarity of the HCl and NH3 release profiles during pyrolysis of IBC-109 supports the hypothesis that the chlorine in coal may be associated with nitrogen and the chlorine is probably bonded to the basic nitrogen sites on the inner walls of coal micropores. ?? 1994 American Chemical Society.

  20. Microbial transformation of chlorinated aromatics in sediments

    NARCIS (Netherlands)

    Beurskens, J.E.M.

    1995-01-01

    Numerous contaminants like heavy metals, polycyclic aromatic hydrocarbons (PAHs), chlorinated benzenes (CBs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo- p -dioxins (PCDDs) and polychlorinated furans (PCDFs) are detected in the major rivers in the Netherl

  1. Chlorine Salts at the Phoenix Landing Site

    Science.gov (United States)

    Hanley, J.; Horgan, B.

    2016-09-01

    Although chlorine salts (perchlorates, chlorides) are known to exist at the Phoenix landing site, their distribution and type have not been positively identified yet. We look for these salts through a novel NIR remote sensing technique.

  2. Modeling Trihalomethane Formation Potential from Wastewater Chlorination

    Science.gov (United States)

    1994-09-01

    chemically with each other, and with living organisms, particularly bacteria ( Manahan , 1991:435). To ensure effective disinfection, to meet the CWA...halogens are strong oxidants and are highly reactive ( Manahan , 1991:504). Chlorine is never found uncombined in nature, it exists only as the...HOCI) according to the following reaction: Cl2 (gas) + H20 =• HOC1 + H+ + Cl The hydrogen is oxidized and the chlorine gas is reduced ( Manahan , 1991

  3. Hydrochloric acid recycling from chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Sowieja, D. [Sulzer Escher Wyss GmbH, Ravensburg (Germany); Schaub, M. [Sulzer Chemtech Ltd., Winterthur (Switzerland)

    1993-12-31

    Chlorinated hydrocarbons present a major ecological hazard since most of them are only poorly biodegradable. Incineration is an economical process for their destruction, however the usually recovered sodium or calcium chlorides do not present a value and their disposal may even be very costly. Recovery of hydrochloric acid may therefore present an economical solution, mainly were large quantities of highly chlorinated compounds can be processed (author) 6 refs., 4 figs., 1 tab.

  4. Chlorinated drinking water for lightweight laying hens

    Directory of Open Access Journals (Sweden)

    A.F. Schneider

    Full Text Available ABSTRACT The study aimed to evaluate the effect of different levels of chlorine in drinking water of laying hens on zootechnical performance, eggs shell quality, hemogasometry levels and calcium content in tibia. 144 Hy-Line laying hens, 61 weeks old, were used distributed in 24 metabolism cages. They were subjected to water diets, for a period of 28 days, using sodium hypochlorite as a chlorine source in order to obtain the following concentrations: 5ppm (control, 20ppm, 50ppm, and 100ppm. Their performance was evaluated through water consumption, feed intake, egg production and weight, egg mass, feed conversion. Shell quality was measured by specific gravity. At the end of the experiment, arterial blood was collected for blood gas level assessment and a poultry of each replicate was sacrificed to obtain tibia and calcium content measurement. There was a water consumption reduction from 20ppm of chlorine and feed intake reduction in poultry receiving water with 100ppm of chlorine. The regression analysis showed that the higher the level of chlorine in water, the higher the reduction in consumption. There were no differences in egg production and weight, egg mass, feed conversion, specific gravity, tibia calcium content, and hemogasometry levels (hydrogenionic potential, carbon dioxide partial pressure, oxygen partial pressure, sodium, potassium, chloride, bicarbonate, carbon dioxide total concentration, anion gap and oxygen saturation. The use of levels above 5ppm of chlorine is not recommended in the water of lightweight laying hens.

  5. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection.

    Science.gov (United States)

    Chusaksri, Sarinma; Sutthivaiyakit, Somyote; Sedlak, David L; Sutthivaiyakit, Pakawadee

    2012-03-30

    Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3'-N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25°C and pH 7 were 0.76 ± 0.16, 0.52 ± 0.11, 0.39 ± 0.02, 0.27 ± 0.04 and 0.23 ± 0.05 M(-1)s(-1) for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be incomplete.

  6. Kinetics of aqueous chlorination of some pharmaceuticals and their elimination from water matrices.

    Science.gov (United States)

    Acero, Juan L; Benitez, F Javier; Real, Francisco J; Roldan, Gloria

    2010-07-01

    Apparent rate constants for the reactions of four selected pharmaceutical compounds (metoprolol, naproxen, amoxicillin, and phenacetin) with chlorine in ultra-pure (UP) water were determined as a function of the pH. It was found that amoxicillin (in the whole pH range 3-12), and naproxen (in the low pH range 2-4) presented high reaction rates, while naproxen (in the pH range 5-9), and phenacetin and metoprolol (in the pH range 2.5-12 for phenacetin, and 3-10 for metoprolol) followed intermediate and slow reaction rates. A mechanism is proposed for the chlorination reaction, which allowed the evaluation of the intrinsic rate constants for the elementary reactions of the ionized and un-ionized species of each selected pharmaceutical with chlorine. An excellent agreement is obtained between experimental and calculated rate constants by this mechanism.The elimination of these substances in several waters (a groundwater, a surface water from a public reservoir, and two effluents from municipal wastewater treatment plants) was also investigated at neutral pH. The efficiency of the chlorination process with respect to the pharmaceuticals elimination and the formation THMs was also established. It is generally observed that the increasing presence of organic and inorganic matter in the water matrices demand more oxidant agent (chlorine), and therefore, less chlorine is available for the oxidation of these compounds. Finally, half-life times and oxidant exposures (CT) required for the removal of 99% of the four pharmaceuticals are also evaluated. These parameters are useful for the establishment of safety chlorine doses in oxidation or disinfection stages of pharmaceuticals in treatment plants.

  7. Role of forage species and conservation method in ruminal lipid metabolism, mammary lipogenesis and milk fatty acid composition in lactating cows

    OpenAIRE

    Halmemies-Beauchet-Filleau, Anni

    2013-01-01

    The objective of the research described in this thesis was to develop forage-rich diets for dairy cows for altering milk fatty acid composition, with the potential to improve human health. Emphasis was placed on the potential to decrease milk fat medium chain saturated fatty acids (SFA; 12:0, 14:0 and 16:0) and increase cis-9 18:1 and polyunsaturated fatty acids (PUFA) concentrations, 18:3n-3 in particular. Experiments encompassed detailed investigations of ruminal and mammary lipid metabolis...

  8. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Chusaksri, Sarinma [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Kasetsart, Bangkok 10900 (Thailand); Sutthivaiyakit, Somyote [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Sedlak, David L., E-mail: sedlak@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Sutthivaiyakit, Pakawadee, E-mail: fscipws@ku.ac.th [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Kasetsart, Bangkok 10900 (Thailand)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Mechanism of chlorine reaction with phenylurea compounds has been studied. Black-Right-Pointing-Pointer It depends on both chlorinating species and substitutents on the compounds. Black-Right-Pointing-Pointer Main products were identified using LC-MS/MS and authentic standards. Black-Right-Pointing-Pointer Their transformation under normal drinking water disinfection was predicted. - Abstract: Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3 Prime -N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25 Degree-Sign C and pH 7 were 0.76 {+-} 0.16, 0.52 {+-} 0.11, 0.39 {+-} 0.02, 0.27 {+-} 0.04 and 0.23 {+-} 0.05 M{sup -1} s{sup -1} for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be

  9. Evaluation of chlorine, chlorine dioxide, and a peroxyacetic acid-based sanitizer for effectiveness in killing Bacillus cereus and Bacillus thuringiensis spores in suspensions, on the surface of stainless steel, and on apples.

    Science.gov (United States)

    Kreske, Audrey C; Ryu, Jee-Hoon; Beuchat, Larry R

    2006-08-01

    Chlorine (10 to 200 microg/ml), chlorine dioxide (10 to 200 microg/ml), and a peroxyacetic acid-based sanitizer (40 and 80 microg/ ml) were evaluated for effectiveness in killing spores of Bacillus cereus and Bacillus thuringiensis in suspensions and on the surface of stainless steel and apples. Water and 5% horse serum were used as carriers for spore inoculum applied to the surface of stainless steel coupons, and 5% horse serum was used as a carrier for inoculum applied to apples. Inocula were dried on stainless steel for 5 h and on apples for 22 to 24 h before treating with sanitizers. At the concentrations of sanitizers tested, sensitivities of planktonic B. cereus and B. thuringiensis spores were similar. A portion of the spores surviving treatment with chlorine and, more markedly, chlorine dioxide had decreased tolerance to heat. Planktonic spores of both species were more sensitive to sanitizers than were spores on the surface of stainless steel or apples. At the same concentrations, chlorine was more effective than chlorine dioxide in killing spores in suspension and on stainless steel. The lethality of chlorine dioxide was markedly reduced when inoculum on stainless steel coupons was suspended in 5% horse serum as a carrier rather than water. Chlorine and chlorine dioxide at concentrations of 10 to 100 microg/ml were equally effective in killing spores on apples. Significant reductions of > or = 3.8 to 4.5 log CFU per apple were achieved by treatment with 100 microg/ml of either of the two sanitizers. The peroxyacetic acid sanitizer (40 and 80 microg/ml) was ineffective in killing Bacillus spores in the test systems investigated. Results provide information on the effectiveness of sanitizers commonly used in the food processing industry in killing Bacillus spores in suspension, on a food-contact surface, and on a ready-to-eat food.

  10. A new kind of Molotov? Gasoline-pool chlorinator mixtures.

    Science.gov (United States)

    Hutches, Katherine; Lord, James

    2012-07-01

    This paper investigates the reaction between pool chlorinators and gasoline. In particular, the propensity for self-ignition and the resulting chemical products were studied. An organic pool chlorinator was combined with gasoline in varying proportions in an attempt to form a hypergolic mixture. None of the combinations resulted in self-ignition, but larger quantities of chlorinator produced vigorous light-colored smoke and a solid mass containing isocyanuric acid and copper chloride. Additionally, the chlorinating abilities of different commercially available pool chlorinators were explored. When Ca(ClO)(2) and sodium dichloro-s-triazinetrione-based chlorinators were used, the presence of gasoline was still visible after 10 days, despite limited chlorination. The trichloro-s-triazinetrione-based chlorinator, however, caused efficient chlorination of the C(2)- and C(3)-alkylbenzenes, making gasoline no longer identifiable.

  11. Blending water- and nutrient-source wastewaters for cost-effective cultivation of high lipid content microalgal species Micractinium inermum NLP-F014.

    Science.gov (United States)

    Park, Seonghwan; Kim, Jeongmi; Yoon, Youngjin; Park, Younghyun; Lee, Taeho

    2015-12-01

    The possibility of utilizing blended wastewaters from different streams was investigated for cost-efficient microalgal cultivation. The influent of a domestic wastewater treatment plant and the liquid fertilizer from a swine wastewater treatment plant were selected as water- and nutrient-source wastewaters, respectively. The growth of Micractinium inermum NLP-F014 in the blended wastewater medium without any pretreatment was comparable to that in Bold's Basal Medium. The optimum blending ratio of 5-15% (vv(-1)) facilitated biomass production up to 5.7 g-dry cell weight (DCW) L(-1), and the maximum biomass productivity (1.03 g-DCWL(-1)d(-1)) was achieved after three days of cultivation. Nutrient depletion induced lipid accumulation in the cell up to 39.1% (ww(-1)) and the maximum lipid productivity was 0.19 g-FAMEL(-1)d(-1). These results suggest that blending water- and nutrient-source wastewaters at a proper ratio without pretreatment can significantly cut costs in microalgae cultivation for biodiesel production.

  12. Determination of lipid-bound sulfate by ion chromatography and its application to quantification of sulfolipids from kidneys of various mammalian species.

    Science.gov (United States)

    Tadano-Aritomi, K; Hikita, T; Suzuki, A; Toyoda, H; Toida, T; Imanari, T; Ishizuka, I

    2001-10-01

    A variety of procedures have been developed for determining the sulfate ester content of various biomolecules. Ion chromatography (IC), that is, quantitation of ionic substances by ion conductimetry after separation by anion-exchange chromatography, has been increasingly utilized for the determination of inorganic sulfate in clinical and environmental samples. We adopted suppressed-mode IC to the determination of lipid- or glycolipid-bound sulfate released by acid hydrolysis and found that it has the advantage of increased precision for wide concentration ranges (30 pmol to approximately micromol) and lack of interference from other lipids. To minimize deterioration of the separation column, the lipophilic constituents in the acid hydrolysate were removed by a two-phase partition system of chloroform-methanol-water. The inorganic sulfate was quantitatively extracted into the aqueous phase by replacing water with an alkaline buffer. By this method, the concentration of sulfolipids was determined in the kidney of mammals with various body mass. Sulfolipids were more concentrated in the kidney of smaller animals, which have higher maximum urine concentrating activity per gram of body mass, supporting the hypothesis of the function of sulfolipids as an ion barrier on the luminal surface of renal tubules.

  13. Formation pathways of brominated products from benzophenone-4 chlorination in the presence of bromide ions

    Institute of Scientific and Technical Information of China (English)

    Ming Xiao; Dongbin Wei; Liping Li; Qi Liu; Huimin Zhao; Yuguo Du

    2014-01-01

    The brominated products,formed in chlorination treatment of benzophenone-4 in the presence of bromide ions,were identified,and the formation pathways were proposed.Under disinfection conditions,benzophenone-4 would undertake electrophilic substitution generating mono-or di-halogenated products,which would be oxidized to esters and further hydrolyzed to phenol derivatives.The generated catechol intermediate would be transformed into furan-like heterocyclic product.The product species were pH-dependent,while benzophenone-4 ehmination was chlorine dose-dependent.When the chlorination treatment was performed on ambient water spiked with benzophenone-4 and bromide ions,most of brominated byproducts could be detected,and the acute toxicity significantly increased as well.

  14. Maxillofacial prostheses of chlorinated polyethylene.

    Science.gov (United States)

    May, P D

    1978-05-01

    There is clearly a need for maxillofacial prosthetic materials with improved properties. The chlorinated polyethylenes are thermoplastic elastomers which have particularly promising properties, and were used by us to prepare improved maxillofacial prostheses. Suitable CPE resins were compounded with other polymers and with pigments on a heated rubber mill to form thin sheets in a variety of shades. These were heated at 190 degrees C for 10 min and placed between heated linotype mold halves. The prosthesis was formed in a hand press. Sometimes heating and pressing were repeated. After cooling in water, the prosthesis was removed and hand-shaded with oil-soluble dyes. Physical properties were evaluated using standard techniques; skin irritation studies were conducted by 14-day insult patch tests on rabbits. Clinical evaluations were conducted on human volunteers. Parallel evaluations were conducted on commerically available materials for comparison. The CPE was superior to all of the three commerical materials in most properties, and comparable to the better of the three in the remaining properties. On balance, CPE was significantly superior. Early results indicate that the materials and techniques required are easily handled in the dental lab and that the final prosthesis has excellent aesthetic and patient acceptability.

  15. Chlorine Abundances in Cool Stars

    CERN Document Server

    Maas, Z G; Hinkle, K

    2016-01-01

    Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\\mu$m. The high resolution L-band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4m telescope. The average [$^{35}$Cl/Fe] abundance in stars with --0.72$<$[Fe/H]$<$0.20 is [$^{35}$Cl/Fe]=(--0.10$\\pm$0.15) dex. The mean difference between the [$^{35}$Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16$\\pm$0.15) dex. The [$^{35}$Cl/Ca] ratio has an offset of $\\sim$0.35 dex above model predictions suggesting chemical evolution models are under producing Cl at the high metallicity range. Abundances of C, N, O, Si, and Ca were also measured in our spectral region and are consistent with F and G dwarfs. The Cl versus O abundances from our sample match Cl abundances measured in planetary nebula and \\ion{H}{2} regions. In one star where both H$^{35}$Cl a...

  16. Formation potentials of typical DBPs and changes of genotoxicity for chlorinated tertiary effluent pretreated by ozone

    Institute of Scientific and Technical Information of China (English)

    CAO Nan; MIAO Tingting; LI Kuixiao; ZHANG Yu; YANG Min

    2009-01-01

    The effects of ozonation on the formation potential of typical disinfection byproducts (DBPs) and the changes of genotoxicity during post chlorination of tertiary effluent from a sewage treatment plant were investigated. Ozonation enhanced the yields of all detected chlorine DBPs except CHCl3. At a chlorine dose of 5 mg/L, the three brominated THMs and five HAAs increased, while chloroform decreased with the increase of ozone dose from 0 to 10 mg/L (ozone dose in consumption base). At a chlorine dose of 10 mg/L, the two mixed bromochloro species THMs and two dominant HAAs (DCAA and TCAA) firstly increased and then decreased with the increase of ozone dose, with the turning point approximately occurring at an ozone dose of 5 mg/L. The genotoxicity detected using umu test, on the other hand, was removed from 7 μg 4-NQO/L to a negligible level by ozonation under an ozone dose of 5 mg/L. Chlorination could further remove the genotoxicity to some extent. It was found that SUVA (UV absorbance divided by DOC concentration) might be used as an indicative parameter for monitoring the removal of genotoxicity during the oxidation.

  17. Reactions of polynuclear aromatic hydrocarbons with chlorine and chlorine dioxide in coal tar lined pipes

    Energy Technology Data Exchange (ETDEWEB)

    Merkel, T.; Maier, M.; Sacher, F.; Maier, D. [University of Karlsruhe, Karlsruhe (Germany). Engler Bunte Institut

    1997-12-31

    In the presence of disinfectants, PAH are remobilised from the coal tar lining of water distribution mains. Reactions of the PAH with chlorine and chlorine dioxide can lead to chlorinated PAH that might show higher mutagenic effects that the parent PAH. Detection limits in the lower nanogram-per-litre level for the determination of PAH and chlorinated PAH were achieved by using solid phase micro extraction and a gas chromatographic mass spectrometric device. Thus, the reactions of four PAH (anthracene, fluoranthene, fluorene and phenanthrene) with chlorine and chlorine dioxide under conditions and at concentrations of common practice in the drinking water distribution system could be investigated. In batch experiments with demineralised and drinking water at pH 7, the concentrations of fluoranthene, fluorene and phenanthrene remained constant, whereas anthracene reacted quantitatively with both disinfectants. The reaction of anthracene followed by pseudo-first order kinetics. In these reactions no chlorinated products could be detected, only monohydroxyanthracene and anthraquinone were identified. The toxic effect of a set of chlorinated and oxidised PAH was also examined.

  18. Rapeseed lecithin hydroxylation by chlorine replacing with hydroxyl groups in chlorinated phospholipids.

    Science.gov (United States)

    Górecki, Michał; Sosada, Marian; Boryczka, Monika; Fraś, Pawel; Pasker, Beata

    2012-01-01

    Rapeseed lecithin ethanol soluble fraction (LESF) was hydroxylated with 30% hydrogen peroxide in the presence of acetic acid. The product was compared to the one obtained by method based on nucleophilic substitution reaction of phospholipids chlorine derivatives. In this approach, hydrogen chloride was added to double bonds in unsaturated acyl groups of phospholipids. Next, chlorine was replaced with hydroxyl groups via the alkaline hydrolysis of chlorine derivatives. The surface active properties of the products obtained with the usage of two methods of rapeseed LESF hydroxylation were determined. The minimal surface tension (eta(min), mN/m) and the critical micelle concentration (CMC, g/L) of LESF hydroxylated with hydrogen peroxide (20.2 mN/m, 6.0 g/L) and obtained by chlorine replacing with hydroxyl groups in chlorinated phospholipids (25.0 mN/m, 9.8 g/L) were compared to LESF (31.8 mN/m, 17.8 g/L). Hydroxylated LESF obtained by lecithin chlorination and chlorine replacing with hydroxyl groups in the chlorine derivatives has no peroxides and the good surface active properties. The product as an effective emulsifier can be used in pharmacy and cosmetics.

  19. Bromate ion formation in dark chlorination and ultraviolet/chlorination processes for bromide-containing water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Bormate (BrO3-) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions,particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet (UV)/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards (10 μg/L). UV irradiation enhanced the decay of free chlorine, and,simultaneously, 6.6%-32% of Br- was oxidized to BrO3-. And the formation of bromate exhibited three stages: rapid stage, slow stage and plateau. Under the experimental conditions (pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L), low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.

  20. Effects of chlorine and chlorine dioxide on human rotavirus infectivity and genome stability.

    Science.gov (United States)

    Xue, Bin; Jin, Min; Yang, Dong; Guo, Xuan; Chen, Zhaoli; Shen, Zhiqiang; Wang, Xinwei; Qiu, Zhigang; Wang, Jingfeng; Zhang, Bin; Li, Junwen

    2013-06-15

    Despite the health risks posed by waterborne human rotavirus (HRV), little information is available concerning the effectiveness of chlorine or chlorine dioxide (ClO2), two common disinfectants of public water sources, against HRV and their effects on its genome remain poorly understood. This study investigated the effects of chlorine and ClO2 on purified HRV by using cell culture and RT-PCR to assess virus infectivity and genetic integrity, respectively. The disinfection efficacy of ClO2 was found to be higher than that of chlorine. According to the efficiency factor Hom model, Ct value (mg/L min) ranges required for a 4-log reduction of HRV at 20 °C by chlorine and ClO2 were 5.55-5.59 and 1.21-2.47 mg/L min, respectively. Detection of the 11 HRV genome segments revealed that damage to the 1227-2354 bp of the VP4 gene was associated with the disappearance of viral infectivity by chlorine. However, no complete accordance between culturing and RT-PCR assays was observed after treatment of HRV with ClO2. These results collectively indicate that the current practice of chlorine disinfection may be inadequate to manage the risk of waterborne HRV infection, and offer the potential to monitor the infectivity of HRV adapting PCR-based protocols in chlorine disinfection. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Possible role of reactive chlorine in microbial antagonism and organic matter chlorination in terrestrial environments

    NARCIS (Netherlands)

    Bengtson, P.; Bastviken, D.; De Boer, W.; Öberg, G.

    2009-01-01

    Several studies have demonstrated that extensive formation of organically bound chlorine occurs both in soil and in decaying plant material. Previous studies suggest that enzymatic formation of reactive chlorine outside cells is a major source. However, the ecological role of microbial-induced extra

  2. Photo-assisted electrochemical degradation of simulated textile effluent coupled with simultaneous chlorine photolysis.

    Science.gov (United States)

    de Mello Florêncio, Thaíla; de Araújo, Karla Santos; Antonelli, Raissa; de Toledo Fornazari, Ana Luiza; da Cunha, Paula Cordeiro Rodrigues; da Silva Bontempo, Letícia Helena; de Jesus Motheo, Artur; Granato, Ana Claudia; Malpass, Geoffroy Roger Pointer

    2016-10-01

    The influence of chloride ion concentration during the photo-assisted electrochemical degradation of simulated textile effluent, using a commercial Ti/Ru0.3Ti0.7O2 anode, was evaluated. Initially, the effect of applied current and supporting electrolyte concentration on the conversion of chloride ions to form reactive chlorine species in 90 min of experiment was analyzed in order to determine the maximum production of reactive chlorine species. The optimum conditions encountered (1.5 A and 0.3 mol dm(-3) NaCl) were subsequently employed for the degradation of simulated textile effluent. The efficiency of the process was determined through the analysis of chemical oxygen demand (COD), total organic carbon (TOC), of the presence of organochlorine products and phytotoxicity. Photo-assisted electrochemical degradation was more efficient for COD and TOC removal than the electrochemical technique alone. With simultaneous UV irradiation, a reduced quantity of reactive chlorine was produced, indicating that photolysis of the chlorine species led to the formation of hydroxyl radicals. This fact turns a simple electrochemical process into an advanced oxidation process.

  3. Chlorine dioxide treatment for zebra mussel control

    Energy Technology Data Exchange (ETDEWEB)

    Rybarik, D. [Dairyland Power Cooperative, La Crosse, WI (United States); Byron, J. [Nalco Chemical Company, Naperville, IL (United States); Germer, M. [Rio Linda Chemical Company, Sacramento, CA (United States)

    1995-06-01

    Chlorine is recognized and commonly used biocide for power plant cooling water and service water treatment programs, including the control of zebra mussels. Chlorine dioxide has recently become a popular method of zebra mussel control because of its economy, safety, environmental acceptability, and effectiveness when compared to other mussel control methods. This control technique was recently demonstrated at Dairyland Power Cooperative`s Alma Generating Station on the east bank of the upper Mississippi River in Alma, Wisconsin. The project was assisted with EPRI Tailored Collaboration Program funds. The Dairyland Power Alam Generating Station consists of five generating units that utilize raw, untreated Mississippi River water for condenser, circulating, and service water supplies. The first units were built in 1947, with the final and largest unit being completed in 1960. Total station generating capacity is 200 MW. Because of recent increases in the zebra mussel density at the station intake, Dairyland Power selected the team of Nalco and Rio Linda to perform a chlorine dioxide treatment of the station`s new water systems to eradicate and control the mussels before their presence created operational difficulties. This paper will present the results of the treatment including treatment theory, design and construction of the treatment system, the method of chlorine dioxide generation, treatment concentration, analytical methods o monitoring chlorine dioxide generation, residuals and trihalomethane (THM) concentrations, protocol for monitoring treatment mortality, and the effects of chlorine dioxide and detoxification on other water chemistry parameters and equipment materials. The goal of this paper is to inform and assist users with establishing consistent and uniform practices for safely utilizing and monitoring chlorine dioxide in the eradication and control of zebra mussels.

  4. Non-heme manganese catalysts for on-demand production of chlorine dioxide in water and under mild conditions.

    Science.gov (United States)

    Hicks, Scott D; Kim, Doyeon; Xiong, Silei; Medvedev, Grigori A; Caruthers, James; Hong, Seungwoo; Nam, Wonwoo; Abu-Omar, Mahdi M

    2014-03-05

    Two non-heme manganese complexes are used in the catalytic formation of chlorine dioxide from chlorite under ambient temperature at pH 5.00. The catalysts afford up to 1000 turnovers per hour and remain highly active in subsequent additions of chlorite. Kinetic and spectroscopic studies revealed a Mn(III)(OH) species as the dominant form under catalytic conditions. A Mn(III)(μ-O)Mn(IV) dinuclear species was observed by EPR spectroscopy, supporting the involvement of a putative Mn(IV)(O) species. First-order kinetic dependence on the manganese catalyst precludes the dinuclear species as the active form of the catalyst. Quantitative kinetic modeling enabled the deduction of a mechanism that accounts for all experimental observations. The chlorine dioxide producing cycle involves formation of a putative Mn(IV)(O), which undergoes PCET (proton coupled electron-transfer) reaction with chlorite to afford chlorine dioxide. The ClO2 product can be efficiently removed from the aqueous reaction mixture via purging with an inert gas, allowing for the preparation of pure chlorine dioxide for on-site use and further production of chlorine dioxide.

  5. Short-chain chlorinated paraffins in marine organisms from the Pearl River Estuary in South China: Residue levels and interspecies differences.

    Science.gov (United States)

    Sun, Runxia; Luo, Xiaojun; Tang, Bin; Li, Zongrui; Huang, Liqian; Wang, Tao; Mai, Bixian

    2016-05-15

    There is limited information available on the bioaccumulation of short-chain chlorinated paraffins (SCCPs), a complicated group of persistent organic pollutants (POPs) candidates listed in the Stockholm Convention, in estuarine ecosystem. This study analyzed SCCPs in marine organisms (five fish and six invertebrates) from the Pearl River Estuary in South China. The concentrations of total SCCPs ranged from 210 to 21,000 ng · g(-1) lipid weight, with relatively higher levels in benthic invertebrates (shrimp, crabs and bivalves) than in non-benthic species (pelagic and mesopelagic fish and squid). SCCPs were biomagnified from prey fish (tapertail anchovy, Coilia mystus) to predator fish (Bombay duck, Harpadon nehereus), and the biomagnification factors (BMFs) of SCCP congeners ranged from 1.1 (C10H16Cl6) to 3.4 (C13H18Cl10). Species-specific homologue group patterns were also observed, with significantly lower proportions of C10 congeners in the shrimp, bivalves and Bombay duck than in the other species.

  6. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine

    Institute of Scientific and Technical Information of China (English)

    Meiquan Cai; Liqiu Zhang; Fei Qi; Li Feng

    2013-01-01

    Owing to its low cost,free chlorine is one of the most common disinfectants for wastewater and drinking water treatment.However,the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades.Antipyrine (ANT),an anti-inflammatory analgesic,has been frequently detected in the aquatic environment.In this work.the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments.The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L,free chlorine dosage from 0.30 to 1.31 mg/L,and pH from 1.5 to 9.0.The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry.The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L,ANT 0.5 mg/L,pH 7.0).Higher oxidant dosage,lower ANT initial concentration and low pH favor the ANT removal.The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-l,2-dihydro1,5-dimethyl-2-phenyl-3H-pyrazol-3-one),which can be further chlorinated by free chlorine.In addition,the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  7. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine.

    Science.gov (United States)

    Cai, Meiquan; Zhang, Liqiu; Qi, Fei; Feng, Li

    2013-01-01

    Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  8. Influence of Plants on Chlorine Cycling in Terrestrial Environments

    Science.gov (United States)

    Montelius, Malin; Thiry, Yves; Marang, Laura; Ranger, Jacques; Cornelis, Jean-Thomas; Svensson, Teresia; Bastviken, David

    2016-04-01

    Chlorine (Cl), one of the 20 most abundant elements on Earth, is crucial for life as a regulator of cellular ionic strength and an essential co-factor in photosynthesis. Chlorinated organic compounds (Clorg) molecules are surprisingly abundant in soils, in fact many studies during the last decades show that Clorg typically account for more than 60% of the total soil Cl pool in boreal and temperate forest soils and frequently exceed chloride (Cl-) levels. The natural and primarily biotic formation of this Clorg pool has been confirmed experimentally but the detailed content of the Clorg pool and the reasons for its high abundance remains puzzling and there is a lack of Cl budgets for different ecosystems. Recently, the radioisotope 36Cl has caused concerns because of presence in radioactive waste, a long half-life (301 000 years), potential high mobility, and limited knowledge about Cl residence times, speciation and uptake by organisms in terrestrial environments. The chlorination of organic molecules may influence the pool of available Cl- to organisms and thereby the Cl cycling dynamics. This will prolong residence times of total Cl in the soil-vegetation system, which affects exposure times in radioactive 36Cl isotope risk assessments. We tested to what extent the dominating tree species influences the overall terrestrial Cl cycling and the balance between Cl- and Clorg. Total Cl and Clorg were measured in different tree compartments and soil horizons in the Breuil experimental forest, Bourgogne, established in 1976 and located at Breuil-Chenue in Eastern France. The results from this field experiment show how the dominating tree species affected Cl cycling and accumulation over a time period of 30 years. Cl uptake by trees as well as content of both total Cl and Clorg in soil humus was much higher in experimental plots with coniferous forests compared to deciduous forests. The amounts of Clorg found in plant tissue indicate significant Clorg production inside

  9. Phosphate valorization by dry chlorination route

    Directory of Open Access Journals (Sweden)

    Kanari N.

    2016-01-01

    Full Text Available This work deals with the extraction of phosphorus chlorinated compounds from phosphate materials using chlorination with gaseous chlorine. An industrial sample of dicalcium phosphate dihydrate, after transformation into calcium pyrophosphate (Ca2P2O7, is subjected to reactions with Cl2+CO+N2 and Cl2+C+N2 at temperatures ranging from 625 to 950°C using boat experiments. Gathering results of the thermodynamic predictions and TG/DT analysis with those of SEM and XRD examinations of the chlorinated residues allowed the interpretation of phenomena and reactions mechanism occurring during the calcium pyrophosphate carbochlorination. Reaction rate of Ca2P2O7 by Cl2+CO+N2 at 950°C is slowed down due to the formation of a CaCl2 liquid layer acting as a barrier for the diffusion of the reactive gases and further reaction progress. While, the carbochlorination with Cl2+C+N2 led to almost full chlorination of Ca2P2O7 at 750°C and the process proceeds with an apparent activation energy of about 104 kJ/mol between 625 and 750°C. Carbochlorination technique can be considered as an alternative and selective route for the valorization of low grade phosphates and for the phosphorus extraction from its bearing materials.

  10. Temporal Decrease in Upper Atmospheric Chlorine

    Science.gov (United States)

    Froidevaux, L.; Livesey, N. J.; Read, W. G.; Salawitch, R. J.; Waters, J. W.; Drouin, B.; MacKenzie, I. A.; Pumphrey, H. C.; Bernath, P.; Boone, C.; hide

    2006-01-01

    We report a steady decrease in the upper stratospheric and lower mesospheric abundances of hydrogen chloride (HCl) from August 2004 through January 2006, as measured by the Microwave Limb Sounder (MLS) aboard the Aura satellite. For 60(deg)S to 60(deg)N zonal means, the average yearly change in the 0.7 to 0.1 hPa (approx.50 to 65 km) region is -27 +/- 3 pptv/year, or -0.78 +/- 0.08 percent/year. This is consistent with surface abundance decrease rates (about 6 to 7 years earlier) in chlorine source gases. The MLS data confirm that international agreements to reduce global emissions of ozone-depleting industrial gases are leading to global decreases in the total gaseous chlorine burden. Tracking stratospheric HCl variations on a seasonal basis is now possible with MLS data. Inferred stratospheric total chlorine (CITOT) has a value of 3.60 ppbv at the beginning of 2006, with a (2-sigma) accuracy estimate of 7%; the stratospheric chlorine loading has decreased by about 43 pptv in the 18-month period studied here. We discuss the MLS HCl measurements in the context of other satellite-based HCl data, as well as expectations from surface chlorine data. A mean age of air of approx. 5.5 years and an age spectrum width of 2 years or less provide a fairly good fit to the ensemble of measurements.

  11. Suppression of chlorine activation on aviation-produced volatile particles

    Directory of Open Access Journals (Sweden)

    S. K. Meilinger

    2002-07-01

    Full Text Available We examine the effect of nm-sized aircraft-induced aqueous sulfuric acid (H2SO4/H2O particles on atmospheric ozone as a function of temperature. Our calculations are based on a previously derived parameterization for the regional-scale perturbations of the sulfate surface area density due to air traffic in the North Atlantic Flight Corridor (NAFC and a chemical box model. We confirm large scale model results that at temperatures T > 210 K additional ozone loss -- mainly caused by hydrolysis of BrONO2 and N2O5 -- scales in proportion with the aviation-produced increase of the background aerosol surface area. However, at lower temperatures (< 210 K we isolate two effects which efficiently reduce the aircraft-induced perturbation: (1 background particles growth due to H2O and HNO3 uptake enhance scavenging losses of aviation-produced liquid particles and (2 the Kelvin effect efficiently limits chlorine activation on the small aircraft-induced droplets by reducing the solubility of chemically reacting species. These two effects lead to a substantial reduction of heterogeneous chemistry on aircraft-induced volatile aerosols under cold conditions. In contrast we find contrail ice particles to be potentially important for heterogeneous chlorine activation and ozone depletion. These features have not been taken into consideration in previous global studies of the atmospheric impact of aviation. Therefore, to parameterize them in global chemistry and transport models, we propose the following parameterisation: scale the hydrolysis reactions by the aircraft-induced surface area increase, and neglect heterogeneous chlorine reactions on liquid plume particles but not on ice contrails and aircraft induced ice clouds.

  12. Suppression of chlorine activation on aviation-produced volatile particles

    Directory of Open Access Journals (Sweden)

    S. K. Meilinger

    2002-01-01

    Full Text Available We examine the effect of nanometer-sized aircraft-induced aqueous sulfuric acid (H2SO4/H2O particles on atmospheric ozone as a function of temperature. Our calculations are based on a previously derived parameterization for the regional-scale perturbations of the sulfate surface area density due to air traffic in the North Atlantic Flight Corridor (NAFC and a chemical box model. We confirm large scale model results that at temperatures T>210 K additional ozone loss -- mainly caused by hydrolysis of BrONO2 and N2O5 -- scales in proportion with the aviation-produced increase of the background aerosol surface area. However, at lower temperatures (2O and HNO3 uptake enhance scavenging losses of aviation-produced liquid particles and (2 the Kelvin effect efficiently limits chlorine activation on the small aircraft-induced droplets by reducing the solubility of chemically reacting species. These two effects lead to a substantial reduction of heterogeneous chemistry on aircraft-induced volatile aerosols under cold conditions. In contrast we find contrail ice particles to be potentially important for heterogeneous chlorine activation and reductions in ozone levels. These features have not been taken into consideration in previous global studies of the atmospheric impact of aviation. Therefore, to parameterize them in global chemistry and transport models, we propose the following parameterisation: scale the hydrolysis reactions by the aircraft-induced surface area increase, and neglect heterogeneous chlorine reactions on liquid plume particles but not on ice contrails and aircraft induced ice clouds.

  13. The molecular face of lipid rafts in model membranes

    NARCIS (Netherlands)

    Risselada, H. Jelger; Marrink, Siewert J.

    2008-01-01

    Cell membranes contain a large number of different lipid species. Such a multicomponent mixture exhibits a complex phase behavior with regions of structural and compositional heterogeneity. Especially domains formed in ternary mixtures, composed of saturated and unsaturated lipids together with

  14. Role of long-chain acyl-CoA synthetase 4 in formation of polyunsaturated lipid species in hepatic stellate cells

    NARCIS (Netherlands)

    Tuohetahuntila, Maidina; Spee, Bart; Kruitwagen, Hedwig S; Wubbolts, Richard; Brouwers, Jos F; van de Lest, Chris H; Molenaar, Martijn R; Houweling, Martin; Helms, J Bernd; Vaandrager, Arie B

    2015-01-01

    Hepatic stellate cell (HSC) activation is a critical step in the development of chronic liver disease. We previously observed that the levels of triacylglycerol (TAG) species containing long polyunsaturated fatty acids (PUFAs) are increased in in vitro activated HSCs. Here we investigated the cause

  15. The effects of low level chlorination and chlorine dioxide on biofouling control in a once-through service water system

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, W.E. Jr. [Alabama Power Co./GSC No. 8, Birmingham, AL (United States); Laylor, M.M. [Univ. of Alabama, Birmingham, AL (United States)

    1995-06-01

    Continuous chlorination has been successfully used for the control of Corbicula at a nuclear power plant located on the Chattahoochee River in southeastern Alabama, since 1986. The purpose of this study was to investigate further minimization of chlorine usage and determine if chlorine dioxide is a feasible alternative. Four continuous biocide treatments were evaluated for macro and microfouling control effectiveness, operational feasibility, and environmental acceptability. One semi-continuous chlorination treatment was also evaluated for macrofouling control effectiveness. Higher treatment residuals were possible with chlorine dioxide than with chlorination due to the river discharge limitations. At the levels tested, continuous chlorine dioxide was significantly more effective in providing both macro and microfouling control. Semi-continuous chlorination was just as effective as continuous chlorination for controlling macrofouling. The Corbicula treatment programs that were tested should all provide sufficient control for zebra mussels. Chlorine dioxide was not as cost effective as chlorination for providing macrofouling control. The semi-continuous treatment save 50% on chemical usage and will allow for the simultaneous treatment of two service water systems. Chlorite levels produced during the chlorine dioxide treatments were found to be environmentally acceptable. Levels of trihalomethanes in the chlorinated service water were less than the maximum levels allowed in drinking water.

  16. Chlorine isotopes potential as geo-chemical tracers

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Pradhan, U.K.; Banerjee, R.

    The potential of chlorine isotopes as tracers of geo-chemical processes of earth and the oceans is highlighted based on systematic studies carried out in understanding the chlorine isotope fractionation mechanism, its constancy in seawater and its...

  17. Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Olsen, Jørn; Villeneuve, Sara

    2013-01-01

    To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF).......To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF)....

  18. Microbiological aspects of the removal of chlorinated hydrocarbons from air

    NARCIS (Netherlands)

    Dolfing, Jan; Wijngaard, Arjan J. van den; Janssen, Dick B.

    1993-01-01

    Chlorinated hydrocarbons are widely used synthetic chemicals that are frequently present in industrial emissions. Bacterial degradation has been demonstrated for several components of this class of compounds. Structural features that affect the degradability include the number of chlorine atoms and

  19. Microbiological aspects of the removal of chlorinated hydrocarbons from air

    NARCIS (Netherlands)

    Dolfing, Jan; Wijngaard, Arjan J. van den; Janssen, Dick B.

    1993-01-01

    Chlorinated hydrocarbons are widely used synthetic chemicals that are frequently present in industrial emissions. Bacterial degradation has been demonstrated for several components of this class of compounds. Structural features that affect the degradability include the number of chlorine atoms and

  20. Distribution coefficients of chlorinated hydrocarbons between muscle tissue and liver in fish. A contribution to the Federal database of environmental samples (UPB); Verteilungskoeffizienten chlorierter Kohlenwasserstoffe zwischen Muskulatur und Leber bei Fischen. Ein Beitrag zur Umweltprobenbank des Bundes (UPB)

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, K.W.; Oxynos, K.; Schmitzer, J. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Oekologische Chemie; Marth, P.; Kettrup, A. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Oekologische Chemie; Technische Univ. Muenchen, Freising (Germany). Lehrstuhl fuer Oekologische Chemie und Umweltanalytik; Wolf, A. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany). Klinische Kooperationsgruppe Umweltdermatologie und Allergologie; Technische Univ. Muenchen (Germany). Klinik und Poliklinik fuer Dermatologie und Allergologie am Biederstein; Hahn, K. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (DE). Inst. fuer Medizinische Informatik und Systemforschung (MEDIS)

    1999-09-01

    Measured distribution coefficients (KL{sub M/L}) related to lipid concentrations between the muscle (C{sub ML}) and liver (C{sub LL}) tissue of two fish species (Abramis brama, Zoarces viviparus) exhibit nominal values of unity according to the relationship KL{sub M/L}=C{sub ML}/C{sub LL}=1 for persistent compounds such as highly chlorinated PCB and values above one for degradable compounds for example chlorinated cyclohexanes or DDT. The corresponding theory is presented. The relationship holds for samples for single fish as well as for pooled samples. (orig.) [German] Lipidbezogene Verteilungskoeffizienten (KL{sub M/L}) zwischen Muskelkonzentrationen- (C{sub ML}) und Leberkonzentrationen (C{sub LL}) zweier Friedfischarten Brassen (Abramis brama) und Aalmutter (Zoarces viviparus) ergeben theoriekonform (KL{sub M/L}=C{sub ML}/C{sub LL}=1) nominale Werte um 1 fuer persistente (hochchlorierte PCB) und Werte ueber 1 fuer metabolisierbare lipophile Umweltchemikalien wie chlorierte Cyclohexane oder DDT. (orig.)

  1. Identification of intermediates leading to chloroform and C-4 diacids in the chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Erkelens, Corrie; Galan, L.

    1985-01-01

    The chlorination of terrestrial humic acid was studied at pH 7. 2 with varying chlorine to carbon ratios. The principal products are chloroform, di- and trichloroacetic acid, and chlorinated C-4 diacids. At a high chlorine dose many new chlorination products were detected, among them chlorinated aro

  2. Trophic ecology of two cold-water coral species from the Mediterranean Sea revealed by lipid biomarkers and compound-specific isotope analyses

    Science.gov (United States)

    Naumann, Malik S.; Tolosa, Imma; Taviani, Marco; Grover, Renaud; Ferrier-Pagès, Christine

    2015-12-01

    Scleractinian cold-water corals (CWC) act as key ecosystem engineers in deep-sea reef environments worldwide. However, our current understanding of their trophic ecology is still limited, particularly in understudied temperate oceanic regions such as the Mediterranean Sea. Hence, this study investigated the trophic ecology of the CWC Desmophyllum dianthus and Madrepora oculata by employing lipid biomarker techniques and compound-specific isotope analyses on coral tissues, suspended particulate organic matter (sPOM), and surface sediment sampled in a Mediterranean CWC habitat. CWC exhibited high contents of poly- and monounsaturated fatty acids (FA) (≥49 and 32 % of FA, respectively) and cholesterol (≥67 % of sterols), while sPOM and sediment samples were enriched in saturated FA (≥44 % of FA) and sitosterol (≥35 % of sterols). CWC contained some rare very long-chained polyunsaturated FA (>C22) and ergosterol absent in sPOM and sediment samples. Our results indicate that Mediterranean CWC mainly consume living food items, rather than detrital sPOM or resuspended sediment, and provide evidence for preferred feeding on omnivorous and carnivorous zooplankton. Overall, these findings provide new insights to the trophic ecology of two common CWC from the Mediterranean Sea.

  3. Chlorine: Undergraduate Research on an Element of Controversy

    Science.gov (United States)

    Chang, Hasok

    2009-04-01

    If chemical elements were people, chlorine would be a celebrity. Although intrinsically no more or less important than any other element, chlorine has had a knack of making headlines. The genre of "object biography" has been quite successful in popular science recently. We took this opportunity to write a "biographical" study of chlorine. Chlorine's wide range of interesting controversies is well suited for attracting and maintaining the enthusiasm of the diverse range of students we teach in our department.

  4. Diurnal variation of stratospheric chlorine monoxide - A critical test of chlorine chemistry in the ozone layer

    Science.gov (United States)

    Solomon, P. M.; De Zafra, R.; Parrish, A.; Barrett, J. W.

    1984-01-01

    Ground-based observations of a mm-wave spectral line at 278 GHz have yielded stratospheric chlorine monoxide column density diurnal variation records which indicate that the mixing ratio and column density of this compound above 30 km are about 20 percent lower than model predictions based on 2.1 parts/billion of total stratospheric chlorine. The observed day-to-night variation is, however, in good agreement with recent model predictions, both confirming the existence of a nighttime reservoir for chlorine and verifying the predicted general rate of its storage and retrieval.

  5. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

    In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

  6. Kinetics and mechanism of styrene epoxidation by chlorite: role of chlorine dioxide.

    Science.gov (United States)

    Leigh, Jessica K; Rajput, Jonathan; Richardson, David E

    2014-07-07

    An investigation of the kinetics and mechanism for epoxidation of styrene and para-substituted styrenes by chlorite at 25 °C in the pH range of 5-6 is described. The proposed mechanism in water and water/acetonitrile includes seven oxidation states of chlorine (-I, 0, I, II, III, IV, and V) to account for the observed kinetics and product distributions. The model provides an unusually detailed quantitative mechanism for the complex reactions that occur in mixtures of chlorine species and organic substrates, particularly when the strong oxidant chlorite is employed. Kinetic control of the reaction is achieved by the addition of chlorine dioxide to the reaction mixture, thereby eliminating a substantial induction period observed when chlorite is used alone. The epoxidation agent is identified as chlorine dioxide, which is continually formed by the reaction of chlorite with hypochlorous acid that results from ClO produced by the epoxidation reaction. The overall stoichiometry is the result of two competing chain reactions in which the reactive intermediate ClO reacts with either chlorine dioxide or chlorite ion to produce hypochlorous acid and chlorate or chloride, respectively. At high chlorite ion concentrations, HOCl is rapidly eliminated by reaction with chlorite, minimizing side reactions between HOCl and Cl2 with the starting material. Epoxide selectivity (>90% under optimal conditions) is accurately predicted by the kinetic model. The model rate constant for direct reaction of styrene with ClO2(aq) to produce epoxide is (1.16 ± 0.07) × 10(-2) M(-1) s(-1) for 60:40 water/acetonitrile with 0.20 M acetate buffer. Rate constants for para substituted styrenes (R = -SO3(-), -OMe, -Me, -Cl, -H, and -NO2) with ClO2 were determined. The results support the radical addition/elimination mechanism originally proposed by Kolar and Lindgren to account for the formation of styrene oxide in the reaction of styrene with chlorine dioxide.

  7. Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Wang, Juan [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhang, Yahe; Shi, Quan [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Zhang, Haifeng; Zhang, Yu [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Yang, Min, E-mail: yangmin@rcees.ac.cn [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2016-06-01

    Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AI{sub mod}), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water. - Highlights: • The formulas of 206 iodinated DBPs in chloraminated drinking water were proposed. • More than 68% of the I-DBPs might have aromatic or polycyclic aromatic structures. • Precursors with high aromaticity is preferential to form iodinated DBPs.

  8. Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry.

    Science.gov (United States)

    Wang, Xin; Wang, Juan; Zhang, Yahe; Shi, Quan; Zhang, Haifeng; Zhang, Yu; Yang, Min

    2016-06-01

    Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AImod), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water.

  9. Efficiency of Chlorine Dioxide as a Bactericide1

    Science.gov (United States)

    Benarde, Melvin A.; Israel, Bernard M.; Olivieri, Vincent P.; Granstrom, Marvin L.

    1965-01-01

    We found chlorine dioxide to be a more effective disinfectant than chlorine in sewage effluent at pH 8.5. Chlorine dioxide was also found to be a more stable bactericide in relation to pH in the range studied. Images Fig. 1 PMID:5325940

  10. Bioaccumulation of persistent organic pollutants (POPs) in fish species from Lake Koka, Ethiopia: The influence of lipid content and trophic position

    Energy Technology Data Exchange (ETDEWEB)

    Deribe, Ermias, E-mail: ermias.weldemariam@umb.no [Norwegian University of Life Sciences, Department of Plant and Environmental Sciences, P.O. Box 5003, N-1432, As (Norway); Hawassa University, Faculty of Natural Sciences, Department of Applied Biology, P.O. Box 5, Awassa (Ethiopia); Rosseland, Bjorn Olav; Borgstrom, Reidar [Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, N-1432, As (Norway); Salbu, Brit [Norwegian University of Life Sciences, Department of Plant and Environmental Sciences, P.O. Box 5003, N-1432, As (Norway); Gebremariam, Zinabu [Higher Education Strategy Center (HESC) P.O. Box 32742, Addis Ababa (Ethiopia); Hawassa University, Faculty of Natural Sciences, Department of Applied Biology, P.O. Box 5, Awassa (Ethiopia); Dadebo, Elias [Hawassa University, Faculty of Natural Sciences, Department of Applied Biology, P.O. Box 5, Awassa (Ethiopia); Norli, Hans Ragnar [Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant Protection Division, Pesticide Chemistry Section, Hogskoleveien 7, N-1432 As (Norway); Eklo, Ole Martin [Norwegian University of Life Sciences, Department of Plant and Environmental Sciences, P.O. Box 5003, N-1432, As (Norway); Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant Protection Division, Pesticide Chemistry Section, Hogskoleveien 7, N-1432 As (Norway)

    2011-12-01

    The concentrations and bioaccumulation of persistent organic pollutants (POPs) were determined in four fish species from Lake Koka, Ethiopia, representing 2-3 levels in the food chain of the lake. Dichlorodiphenyltrichloroethanes (DDTs), endosulfans, polychlorinated biphenyls (PCBs) and chlorpyrifos were identified, with DDTs as the most predominant pesticide, with concentration ranging from 0.05 to 72.53 ng g{sup -1} wet weight (ww). All fish tissue samples collected from different species of the lake contained residues of DDTs. The maximum level of DDTs was found in the fattiest, African sharptooth catfish (Clarias gariepinus) sampled from the lake, with a mean concentration of 15.15 ng g{sup -1}ww. The significant (P < 0.05) relationship between concentrations of DDTs and {delta}{sup 15}N indicates that DDTs biomagnified in the food web of the lake. The 4,4 Prime -DDE to 4,4 Prime -DDT ratio in Oreochromis niloticus (0.6) and Cyprinus carpio (0.5) were below 1, indicating ongoing use of DDTs in the study area and recent exposure of these fish species.

  11. Phytotoxicity of chlorinated benzenes to Typha angustifolia and Phragmites communis.

    Science.gov (United States)

    Ma, Xingmao; Havelka, Megan M

    2009-02-01

    Healthy growth of plants is a prerequisite for successful application of phytoremediation technologies. Typha angustifolia and Phragmites communis are common wetland plants and have shown potential for phytoremediation of hexachlorobenzene (HCB). However, the lack of phytotoxicity data impedes their application in field sites. This study investigated the phytotoxicity of HCB, and its two metabolites: 1,3,5-trichlorobenzene (1,3,5-TCB) and 1,4-dichlorobenzene (1,4-DCB) to Typha and the phytotoxicity of 1,3,5-TCB to Phragmites. The phytotoxicity of 1,3,5-TCB is species-dependent, with Typha demonstrating significantly higher tolerance than Phragmites. The concentration of 1,3,5-TCB causing zero growth of Phragmites was determined to be 1575 mg TCB/kg dry sediment. The concentration has to be doubled to completely inhibit the growth of Typha. Adverse effects of chlorinated benzenes in sediments on Typha increased with decreasing chlorine atoms. The concentrations causing zero growth of Typha are 5765 mg HCB/kg dry soil, 3157 mg 1,3,5-TCB/kg dry soil, and 1325 mg 1,4-DCB/kg dry soil. The higher toxicity of 1,4-DCB than 1,3,5-TCB and HCB in sediment was ascribed to its higher availability and easiness to be taken up by plants. The conclusion was supported by both growth rate calculations and plant height measurements. (c) 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.

  12. Vortex-wide chlorine activation by a mesoscale PSC event in the Arctic winter of 2009/10

    Science.gov (United States)

    Wegner, Tobias; Pitts, Michael C.; Poole, Lamont R.; Tritscher, Ines; Grooß, Jens-Uwe; Nakajima, Hideaki

    2016-04-01

    In the Arctic polar vortex of the 2009/10 winter temperatures were low enough to allow widespread formation of polar stratospheric clouds (PSCs). These clouds occurred during the initial chlorine activation phase which provided the opportunity to investigate the impact of PSCs on chlorine activation. Satellite observations of gas-phase species and PSCs are used in combination with trajectory modeling to assess this initial activation. The initial activation occurred in association with the formation of PSCs over the east coast of Greenland at the beginning of January 2010. Although this area of PSCs covered only a small portion of the vortex, it was responsible for almost the entire initial activation of chlorine vortex wide. Observations show HCl (hydrochloric acid) mixing ratios decreased rapidly in and downstream of this region. Trajectory calculations and simplified heterogeneous chemistry modeling confirmed that the initial chlorine activation continued until ClONO2 (chlorine nitrate) was completely depleted and the activated air masses were advected throughout the polar vortex. For the calculation of heterogeneous reaction rates, surface area density is estimated from backscatter observations. Modeled heterogeneous reaction rates along trajectories intersecting with the PSCs indicate that the initial phase of chlorine activation occurred in just a few hours. These calculations also indicate that chlorine activation on the binary background aerosol is significantly slower than on the PSC particles and the observed chlorine activation can only be explained by an increase in surface area density due to PSC formation. Furthermore, there is a strong correlation between the magnitude of the observed HCl depletion and PSC surface area density.

  13. Inactivation of three genera of dominant fungal spores in groundwater using chlorine dioxide: Effectiveness, influencing factors, and mechanisms.

    Science.gov (United States)

    Wen, Gang; Xu, Xiangqian; Huang, Tinglin; Zhu, Hong; Ma, Jun

    2017-08-18

    Fungi in aquatic environments received more attention recently; therefore, the characteristics of inactivation of fungal spores by widely used disinfectants are quite important. Nonetheless, the inactivation efficacy of fungal spores by chlorine dioxide is poorly known. In this study, the effectiveness of chlorine dioxide at inactivation of three dominant genera of fungal spores isolated from drinking groundwater and the effects of pH, temperature, chlorine dioxide concentration, and humic acid were evaluated. The inactivation mechanisms were explored by analyzing the leakage of intracellular substances, the increase in extracellular adenosine triphosphate (ATP), deoxyribonucleic acid (DNA), and proteins as well as the changes in spore morphology. The kinetics of inactivation by chlorine dioxide fitted the Chick-Watson model, and different fungal species showed different resistance to chlorine dioxide inactivation, which was in the following order: Cladosporium sp.>Trichoderma sp. >Penicillium sp., which are much more resistant than Escherichia coli. Regarding the three genera of fungal spores used in this study, chlorine dioxide was more effective at inactivation of fungal spores than chlorine. The effect of disinfectant concentration and temperature was positive, and the impact of pH levels (6.0 and 7.0) was insignificant, whereas the influence of water matrices on the inactivation efficiency was negative. The increased concentration of characteristic extracellular substances and changes of spore morphology were observed after inactivation with chlorine dioxide and were due to cell wall and cell membrane damage in fungal spores, causing the leakage of intracellular substances and death of a fungal spore. Copyright © 2017. Published by Elsevier Ltd.

  14. Chlorination of nickel ore by gaseous chlorine in the presence of active additives

    Directory of Open Access Journals (Sweden)

    Ilić Ilija B.

    2003-01-01

    Full Text Available Paper presents a thermodynamic analysis of chemical reactions occurring during chlorination with and without additives for both nickel oxides and nickel ferrites, which are component parts of nickel ore. The experimental research investigated the influence of temperature in the range from 600 up to 1000 °C and time (up to 3 h on the chlorination degree of nickel ores with and without additives. It was found that the introduction of additives such as C, S, BaS and NaCl intensified the chlorination of nickel ore. The results can be applied and may help determine the optimal conditions for the chlorination of low-grade ferrous nickel ores.

  15. Alterations of retinol-binding protein 4 species in patients with different stages of chronic kidney disease and their relation to lipid parameters

    DEFF Research Database (Denmark)

    Henze, Andrea; Frey, Simone K; Raila, Jens;

    2010-01-01

    Retinol-binding protein 4 (RBP4) is elevated in patients with chronic kidney disease (CKD) and has been discussed as marker of kidney function. In addition to an elevated concentration, the existence of truncated RBP4 species, RBP4-L (truncated at last C-terminal leucine) and RBP4-LL (truncated......) was assessed in serum of 45 healthy controls and 52 patients with stage 2-5 of CKD using ELISA and RBP4 immunoprecipitation with subsequent MALDI-TOF-MS analysis. A reduction of glomerular filtration rate was accompanied by a gradual elevation of RBP4 serum levels and relative amounts of RBP4-LL. Correlation...

  16. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    OpenAIRE

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested o...

  17. Method and apparatus for producing chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Santillie, P.W.; Ramras, D.M.

    1984-05-29

    A continuous method and apparatus are described for the efficient production of gaseous chlorine dioxide by the reaction between gaseous sulfur dioxide and an aqueous solution of a metallic chlorate. The chlorate solution and a highly concentrated sulfur dioxide gas are introduced into a packed columnar chamber at closely adjacent locations at the bottom of the chamber so as to flood the chamber and maximize both the contact area and contact time of the two reactants. Throughout the reaction the chamber is subjected to high vacuum imposed by an eductor which exhausts the chlorine dioxide gas and spent reactants. For use of the chlorine dioxide to produce potable water or treat foodstuffs, the chlorine dioxide and spent reactants are exhausted from the chamber separately by respective eductors substantially balanced with respect to each other to impose comparable vacuums upon the chamber. Because of the high efficency of the reaction, substantial heat is generated therefrom which is absorbed by a coolant flowing through a jacket surrounding the chamber. The flow rate of the coolant and flow rate of the reactants into the chamber are porportional due to the dependency of the reactant flow rate on the coolant flow rate.

  18. Photoabsorption and photoionization of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Flesch, R.; Ruehl, E.; Hottmann, K.; Baumgaertel, H. (Freie Universitaet Berlin (Germany))

    1993-01-28

    Photoprocesses of chlorine dioxide in the near-UV have become highly important for stratospheric photoprocesses at high latitudes, especially in Antarctica. Chlorine dioxide has been identified among other absorbers because of its specific absorption cross section in the near-UV. Possible contributions of chlorine dioxide photochemistry to polar ozone depletion have been discussed recently. The high-resolution He I photoelectron spectrum and the absolute (vacuum-UV) absorption cross section (6-25 eV) as well as the ionic fragmentation of chlorine dioxide (OCIO) are reported. The photoelectron spectrum is interpreted in terms of exchange splitting effects of the various singlet and triplet cation states as well as by comparison to chemically related molecules. The vacuum-UV absorption spectrum shows different Rydberg series converging to the cation states. These Rydberg series and their vibrational progressions are assigned by term value arguments, dipole selection rules, and comparison with the photoelectron spectrum. Photoionization mass spectrometry is used for measurements of the ionization and fragmentation threshold of OCIO. The major fragment is ClO[sup +] which occurs above 13.4 eV. Thermomechanical data such as heats of formation and bond dissociation energies are derived. No evidence for isomerization of OClO[sup +] is found, as observed for the electronically excited neutral molecule. 54 refs., 6 figs., 7 tabs.

  19. Inhibitor treatment program for chlorine dioxide corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Edmondson, J.G.; Holder, E.P.

    1991-11-12

    This patent describes a method of inhibiting corrosion by chlorine dioxide in oil field waterflood systems by adding a sufficient amount of a corrosion inhibiting composition. It comprises a phosphonate, a copolymer consisting of repeating units of acrylic acid/allyl hydroxy propyl sulfonate ether, and a permangante.

  20. Chlorinated organic compounds in urban river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Soma, Y.; Shiraishi, H.; Inaba, K. [National Inst. of Environmental Studies, Tsukuba, Ibaraki (Japan)

    1995-12-31

    Among anthropogenic chemicals, many chlorinated organic compounds have been used as insecticides and detected frequently as contaminants in urban river sediments so far. However, the number and total amount of chemicals produced commercially and used are increasing year by year, though each amount of chemicals is not so high. New types of contaminants in the environment may be detected by the use of newly developed chemicals. Chlorinated organic compounds in the urban river sediments around Tokyo and Kyoto, large cities in Japan, were surveyed and recent trends of contaminants were studied. Contaminants of the river sediments in industrial areas had a variety, but PCB (polychlorinated biphenyls) was detected in common in industrial areas. Concentration of PCB related well to the number of factories on both sides of rivers, although the use of PCB was stopped 20 years ago. In domestic areas, Triclosan (5-chloro-2-(2,4-dichlorophenoxy)-phenol) and Triclocarban (3,4,4{prime}-trichlorocarbanilide)(both are contained in soap or shampoo for fungicides), p-dichlorobenzene (insecticides for wears) and TCEP(tris-chloroethyl phosphate) were detected. EOX(extracted organic halogen) in the sediments was 5 to 10 times of chlorinated organic compounds detected by GC/MS. Major part of organic halogen was suggested to be included in chlorinated organics formed by bleaching or sterilization.

  1. Occurrence, bioaccumulation and long-range transport of short-chain chlorinated paraffins on the Fildes Peninsula at King George Island, Antarctica.

    Science.gov (United States)

    Li, Huijuan; Fu, Jianjie; Zhang, Aiqian; Zhang, Qinghua; Wang, Yawei

    2016-09-01

    As a candidate persistent organic pollutant of the Stockholm Convention, short-chain chlorinated paraffins (SCCPs) have recently received particular attention. In this study, we investigated, for the first time, the concentrations of SCCPs in biota samples collected from the Fildes Peninsula at King George Island and Ardley Island, Antarctica. The concentrations of SCCPs ranged from 3.5 to 256.6ng/g (dry weight, dw), with a mean of 76.6±61.8ng/g dw, which was lower than those detected in mid- and low-latitude regions. The long-range transport behaviour of SCCPs was confirmed by both the detection of SCCPs in Antarctic remote areas and their special congener profiles. Short carbon chain (C10) congeners predominated in the Antarctic samples, which accounted for 56.1% of the total SCCP contamination. Such enrichment of C10 congeners indicated the high potential for the long-range transport of shorter chain congeners. In addition, SCCPs tended to be enriched in the species with high lipid contents. The biomagnification potential of SCCPs was found between Archeogastropoda (Agas) and Neogastropoda (Ngas), and the biomagnification factors of shorter chain congeners of SCCPs were higher than that of the longer chain ones. Considering that the endemic species in polar regions may be sensitive and vulnerable to the adverse effects of environmental contaminants, more attention should be paid on the bioaccumulation and toxicological risks of SCCPs in polar environments.

  2. Modelling Of Chlorine Inductive Discharges

    Science.gov (United States)

    Chabert P.; Despiau-Pujo, E.

    2010-07-01

    .02, which is much lower than the value predicted for stainless steel walls (? = 0.6). This is consistent with reactor wall contaminations classi- cally observed in such discharges. The plasma electronegativity decreases with RF power and increases with Cl2 content. At high pressure, the power absorption and distribution of charged particles become more localized below the quartz window. Although the experi- mental trends are well reproduced by the model, the calculated charged particle densities are systematically overestimated by a factor of 3-5. The reasons for this discrepancy are discussed in the paper. Experimental studies have also shown that low-pressure inductive discharges operating with electronegative gases are subject to instabilities near the transition between capacitive (E) and inductive (H) modes. A global model, consisting of two particle balance equations and one energy balance equation, has been previously proposed to describe the instability mechanism in SF6/ArSF6 (Lieberman et al. 1999). This model, which agrees qualitatively well with experimental observations, leaves significant quantitative differences. In this work, this global model is revisited with Cl2 as the feedstock gas (Despiau-Pujo and Chabert 2009). An alternative treatment of the inductive power deposition is evaluated and chlorine chemistry is included. Old and new models are systematically compared. The alternative inductive coupling description slightly modifies the results. The effect of gas chemistry is even more pronounced. The instability window is smaller in pressure and larger in absorbed power, the frequency is higher and the amplitudes of oscillations are reduced. The feedstock gas is weakly dissociated (~16%) and Cl2+ is the dominant positive ion, which is consistent with the moderate electron density during the instability cycle.

  3. Depletion of chlorine into HCl ice in a protostellar core. The CHESS spectral survey of OMC-2 FIR 4

    Science.gov (United States)

    Kama, M.; Caux, E.; López-Sepulcre, A.; Wakelam, V.; Dominik, C.; Ceccarelli, C.; Lanza, M.; Lique, F.; Ochsendorf, B. B.; Lis, D. C.; Caballero, R. N.; Tielens, A. G. G. M.

    2015-02-01

    Context. The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances OMC-2 FIR 4. Methods: We observed transitions of HCl and H2Cl+ towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H2 hyperfine collisional excitation rate coefficients. Results: A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9 × 10-11, a factor of only 10-3 that of volatile elemental chlorine. The H2Cl+ lines are detected in absorption and trace a tenuous foreground cloud, where we find no depletion of volatile chlorine. Conclusions: Gas-phase HCl is the tip of the chlorine iceberg in protostellar cores. Using a gas-grain chemical model, we show that the hydrogenation of atomic chlorine on grain surfaces in the dark cloud stage sequesters at least 90% of the volatile chlorine into HCl ice, where it remains in the protostellar stage. About 10% of chlorine is in gaseous atomic form. Gas-phase HCl is a minor, but diagnostically key reservoir, with an abundance of ≲10-10 in most of the protostellar core. We find the [35Cl]/[37Cl] ratio in OMC-2 FIR 4 to be 3.2 ± 0.1, consistent with the solar system value. Appendices are available in electronic form at http://www.aanda.org

  4. Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis.

    Science.gov (United States)

    Hering, Thea; Mühldorf, Bernd; Wolf, Robert; König, Burkhard

    2016-04-18

    Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic precursors for metal-catalyzed cross-couplings. Nature chlorinates with chloride anions, FAD-dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket.

  5. Turbidity and chlorine demand reduction using alum and moringa flocculation before household chlorination in developing countries.

    Science.gov (United States)

    Preston, Kelsey; Lantagne, Daniele; Kotlarz, Nadine; Jellison, Kristen

    2010-03-01

    Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l(-1) sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.

  6. Kinetic models and pathways of ronidazole degradation by chlorination, UV irradiation and UV/chlorine processes.

    Science.gov (United States)

    Qin, Lang; Lin, Yi-Li; Xu, Bin; Hu, Chen-Yan; Tian, Fu-Xiang; Zhang, Tian-Yang; Zhu, Wen-Qian; Huang, He; Gao, Nai-Yun

    2014-11-15

    Degradation kinetics and pathways of ronidazole (RNZ) by chlorination (Cl2), UV irradiation and combined UV/chlorine processes were investigated in this paper. The degradation kinetics of RNZ chlorination followed a second-order behavior with the rate constants calculated as (2.13 ± 0.15) × 10(2) M(-2) s(-1), (0.82 ± 0.52) × 10(-2) M(-1) s(-1) and (2.06 ± 0.09) × 10(-1) M(-1) s(-1) for the acid-catalyzed reaction, as well as the reactions of RNZ with HOCl and OCl(-), respectively. Although UV irradiation degraded RNZ more effectively than chlorination did, very low quantum yield of RNZ at 254 nm was obtained as 1.02 × 10(-3) mol E(-1). RNZ could be efficiently degraded and mineralized in the UV/chlorine process due to the generation of hydroxyl radicals. The second-order rate constant between RNZ and hydroxyl radical was determined as (2.92 ± 0.05) × 10(9) M(-1) s(-1). The degradation intermediates of RNZ during the three processes were identified with Ultra Performance Liquid Chromatography - Electrospray Ionization - mass spectrometry and the degradation pathways were then proposed. Moreover, the variation of chloropicrin (TCNM) and chloroform (CF) formation after the three processes were further evaluated. Enhanced formation of CF and TCNM precursors during UV/chlorine process deserves extensive attention in drinking water treatment.

  7. Wheat leaf lipids during heat stress: II. Lipids experiencing coordinated metabolism are detected by analysis of lipid co-occurrence.

    Science.gov (United States)

    Narayanan, Sruthi; Prasad, P V Vara; Welti, Ruth

    2016-03-01

    Identifying lipids that experience coordinated metabolism during heat stress would provide information regarding lipid dynamics under stress conditions and assist in developing heat-tolerant wheat varieties. We hypothesized that co-occurring lipids, which are up-regulated or down-regulated together through time during heat stress, represent groups that can be explained by coordinated metabolism. Wheat plants (Triticum aestivum L.) were subjected to 12 days of high day and/or night temperature stress, followed by a 4-day recovery period. Leaves were sampled at four time points, and 165 lipids were measured by electrospray ionization-tandem mass spectrometry. Correlation analysis of lipid levels in 160 leaf samples from each of two wheat genotypes revealed 13 groups of lipids. Lipids within each group co-occurred through the high day and night temperature stress treatments. The lipid groups can be broadly classified as groups containing extraplastidic phospholipids, plastidic glycerolipids, oxidized glycerolipids, triacylglycerols, acylated sterol glycosides and sterol glycosides. Current knowledge of lipid metabolism suggests that the lipids in each group co-occur because they are regulated by the same enzyme(s). The results suggest that increases in activities of desaturating, oxidizing, glycosylating and acylating enzymes lead to simultaneous changes in levels of multiple lipid species during high day and night temperature stress in wheat.

  8. Computational Modeling of Lipid Metabolism in Yeast

    Directory of Open Access Journals (Sweden)

    Vera Schützhold

    2016-09-01

    Full Text Available Lipid metabolism is essential for all major cell functions and has recently gained increasing attention in research and health studies. However, mathematical modeling by means of classical approaches such as stoichiometric networks and ordinary differential equation systems has not yet provided satisfactory insights, due to the complexity of lipid metabolism characterized by many different species with only slight differences and by promiscuous multifunctional enzymes.Here, we present a object-oriented stochastic model approach as a way to cope with the complex lipid metabolic network. While all lipid species are treated objects in the model, they can be modified by the respective converting reactions based on reaction rules, a hybrid method that integrates benefits of agent-based and classical stochastic simulation. This approach allows to follow the dynamics of all lipid species with different fatty acids, different degrees of saturation and different headgroups over time and to analyze the effect of parameter changes, potential mutations in the catalyzing enzymes or provision of different precursors. Applied to yeast metabolism during one cell cycle period, we could analyze the distribution of all lipids to the various membranes in time-dependent manner.The presented approach allows to efficiently treat the complexity of cellular lipid metabolism and to derive conclusions on the time- and location-dependent distributions of lipid species and their properties such as saturation. It is widely applicable, easily extendable and will provide further insights in healthy and diseased states of cell metabolism.

  9. Validation study for crediting chlorine in criticality analyses for spent nuclear fuel disposition

    Energy Technology Data Exchange (ETDEWEB)

    Sobes, Vladimir [ORNL; Scaglione, John M [ORNL; Wagner, John C [ORNL; Dunn, Michael E [ORNL

    2015-01-01

    Spent nuclear fuel (SNF) management practices in the United States rely on dry storage systems that include both canister- and cask-based systems. The United States Department of Energy Used Fuel Disposition Campaign is examining the feasibility of direct disposal of dual-purpose (storage and transportation) canisters (DPCs) in a geological repository. One of the major technical challenges for direct disposal is the ability to demonstrate the subcriticality of the DPCs loaded with SNF for the repository performance period (e.g., 10,000 years or more) as the DPCs may undergo degradation over time. Specifically, groundwater ingress into the DPC (i.e., flooding) could allow the system to achieve criticality in scenarios where the neutron absorber plates in the DPC basket have degraded. However, as was shown by Banerjee et al., some aqueous species in the groundwater provide noticeable reactivity reduction for these systems. For certain amounts of particular aqueous species (e.g., chlorine, lithium) in the groundwater, subcriticality can be demonstrated even for DPCs with complete degradation of the neutron absorber plates or a degraded fuel basket configuration. It has been demonstrated that chlorine is the leading impurity, as indicated by significant neutron absorption in the water that is available in reasonable quantities for the deep geological repository media under consideration. This paper presents the results of an investigation of the available integral experiments worldwide that could be used to validate DPC disposal criticality evaluations, including credit for chlorine. Due to the small number of applicable critical configurations, validation through traditional trending analysis was not possible. The bias in the eigenvalue of the application systems due only to the chlorine was calculated using TSURFER analysis and found to be on the order of 100 percent mille (1 pcm = 10-5 keff). This study investigated the design of a series of

  10. Validation Study for Crediting Chlorine in Criticality Analyses for US Spent Nuclear Fuel Disposition

    Energy Technology Data Exchange (ETDEWEB)

    Sobes, Vladimir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Scaglione, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wagner, John C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dunn, Michael E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    Spent nuclear fuel (SNF) management practices in the United States rely on dry storage systems that include both canister- and cask-based systems. The United States Department of Energy Used Fuel Disposition Campaign is examining the feasibility of direct disposal of dual-purpose (storage and transportation) canisters (DPCs) in a geological repository. One of the major technical challenges for direct disposal is the ability to demonstrate the subcriticality of the DPCs loaded with SNF for the repository performance period (e.g., 10,000 years or more) as the DPCs may undergo degradation over time. Specifically, groundwater ingress into the DPC (i.e., flooding) could allow the system to achieve criticality in scenarios where the neutron absorber plates in the DPC basket have degraded. However, as was shown by Banerjee et al., some aqueous species in the groundwater provide noticeable reactivity reduction for these systems. For certain amounts of particular aqueous species (e.g., chlorine, lithium) in the groundwater, subcriticality can be demonstrated even for DPCs with complete degradation of the neutron absorber plates or a degraded fuel basket configuration. It has been demonstrated that chlorine is the leading impurity, as indicated by significant neutron absorption in the water that is available in reasonable quantities for the deep geological repository media under consideration. This paper presents the results of an investigation of the available integral experiments worldwide that could be used to validate DPC disposal criticality evaluations, including credit for chlorine. Due to the small number of applicable critical configurations, validation through traditional trending analysis was not possible. The bias in the eigenvalue of the application systems due only to the chlorine was calculated using TSURFER analysis and found to be on the order of 100 percent mille (1 pcm = 10-5 keff). This study investigated the design of a series of

  11. Comparative chlorine and temperature tolerance of the oyster Crassostrea madrasensis: implications for cooling system fouling.

    Science.gov (United States)

    Rajagopal, S; Venugopalan, V P; van der Velde, G; Jenner, H A

    2003-04-01

    Crassostrea madrasensis is an important fouling oyster in tropical industrial cooling water systems. C. madrasensis individuals attach to surfaces by cementing one of their two valves to the substratum. Therefore, oyster fouling creates more problems than mussel fouling in the cooling conduits of power stations, because unlike the latter, the shell of the former remains attached to the substratum even after the death of the animal. However, there are no published reports on the tolerance of this species to chlorination and heat treatment. The mortality pattern and physiological behaviour (oxygen consumption and filtration rate) of three size groups (13 mm, 44 mm and 64 mm mean shell length) of C. madrasensis were studied at different residual chlorine concentrations (0.25, 0.5, 0.75, 1, 2, 3 to 5 mg 1-1) and temperatures (30 degrees C to 45 degrees C). The effect of shell size (= age) on C. madrasensis mortality in the presence of chlorine and taking into account temperature was significant, with the largest size group oysters showing highest resistance. At 1 mg l-1 residual chlorine, the 13 mm and 64 mm size group oysters, took 504 h (21 d) and 744 h (31 d), respectively to reach 100% mortality. At 39 degrees C, the 13 mm size group oysters took 218 min to reach 100% mortality, whereas the 64 mm size group oysters took 325 min. The oxygen consumption and filtration rate of C. madrasensis showed progressive reduction with increasing residual chlorine concentrations. However, the filtration rate and oxygen consumption responses of C. madrasensis were not significantly different between 30 degrees C (control) and 37.5 degrees C. There was a sharp decrease in the filtration rate and oxygen consumption at 38.5 degrees C. A comparison of the present mortality data with previous reports on other bivalves suggests that the chlorine tolerance of C. madrasensis lies in between that of Perna viridis and Perna perna, while its temperature tolerance is significantly higher

  12. Reactive chlorine chemistry in the boundary layer of coastal Antarctica

    Science.gov (United States)

    Zielcke, Johannes; Poehler, Denis; Friess, Udo; Hay, Tim; Eger, Philipp; Kreher, Karin; Platt, Ulrich

    2015-04-01

    A unique feature of the polar troposphere is the strong impact of halogen photochemistry, in which reactive halogen species are responsible for ozone depletion as well as the oxidation of elemental mercury and dimethyl sulphide. The source, however, as well as release and recycling mechanisms of these halogen species - for some species even abundances - are far from being completely known, especially of chlorine and iodine compounds. Here we present active long-path differential optical absorption spectroscopy (LP-DOAS) measurements conducted during austral spring 2012 at Ross Island, Antarctica, observing several species (BrO, O3, NO2, IO, ClO, OBrO, OClO, OIO, I2, CHOCHO, HCHO, HONO). For the first time, ClO was detected and quantified in the marine boundary layer of coastal Antarctica, with typical mixing ratios around 20 pptv and maxima around 50 pptv. Meteorological controls on the mixing ratio of ClO as well as the interplay with other halogen compounds will be discussed, such as the lack of observed OClO (< 1 pptv). The results seem to reflect previously in chamber studies observed dependences on ozone levels and solar irradiance.

  13. Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Linxi; Campo, Pablo; Kupferle, Margaret J., E-mail: margaret.kupferle@uc.edu

    2015-02-11

    Graphical abstract: - Highlights: • By-products from anodic oxidation of phenol in the presence of chloride are investigated. • Chlorinated oligomer formation is demonstrated by LC-QTOF-MS. • They have structures similar to triclosan and polychlorinated dibenzo-p-dioxins. - Abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5 mM and 50 mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl{sup −} led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins.

  14. Contrasting effects of sulfur dioxide on cupric oxide and chloride during thermochemical formation of chlorinated aromatics.

    Science.gov (United States)

    Fujimori, Takashi; Nishimoto, Yoshihiro; Shiota, Kenji; Takaoka, Masaki

    2014-12-01

    Sulfur dioxide (SO2) gas has been reported to be an inhibitor of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) formation in fly ash. However, other research has suggested little or no inhibitory effect of SO2 gas. Although these studies focused on reactions between SO2 gas and gas-phase chlorine (Cl) species, no attention was paid to thermochemical gas-solid reactions. In this study, we found contrasting effects of SO2 gas depending on the chemical form of copper (CuO vs CuCl2) with a solid-phase inorganic Cl source (KCl). Chlorinated aromatics (PCDD/Fs, polychlorinated biphenyls, and chlorobenzenes) increased and decreased in model fly ash containing CuO + KCl and CuCl2 + KCl, respectively, with increased SO2 injection. According to in situ Cu K-edge and S K-edge X-ray absorption spectroscopy, Cl gas and CuCl2 were generated and then promoted the formation of highly chlorinated aromatics after thermochemical reactions of SO2 gas with the solid-phase CuO + KCl system. In contrast, the decrease in aromatic-Cls in a CuCl2 + KCl system with SO2 gas was caused mainly by the partial sulfation of the Cu. The chemical form of Cu (especially the oxide/chloride ratio) may be a critical factor in controlling the formation of chlorinated aromatics using SO2 gas.

  15. Electrochemically activated water as an alternative to chlorine for decentralized disinfection

    KAUST Repository

    Ghebremichael, Kebreab A.

    2011-06-01

    Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive oxygen species such as ozone and hydroxyl radicals in addition to chlorine. This study compares sodium hypochlorite (NaOCl) and ECA in terms of disinfection efficacy, trihalomethanes (THMs) formation, stability and composition. The studies were carried out under different process conditions (pH 5,7 and 9, disinfectant concentrations of 2-5 mg/L and dissolved organic carbon (DOC) concentration of 2-4 mg/L). The results indicated that in the presence of low DOC (<2 mg/L) ECA showed better disinfection efficacy for Escherichia coli inactivation, formed lower THM and had better stability compared with NaOCl at both pH 5 and 7. Stability studies of stock solutions showed that over a period of 30 days, ECA decayed by only 5% while NaOCl decayed by 37.5% at temperatures of 4 °C. In a fresh ECA of 200 mg/L chlorine, about 5.3 mg/L ozone and 36.9 mg/L ClO2 were detected. The study demonstrates that ECA could be a suitable alternative to NaOCl where decentralized production and use are required. © IWA Publishing 2011.

  16. Oxidative elimination of cyanotoxins: comparison of ozone, chlorine, chlorine dioxide and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Onstad, Gretchen D; Kull, Tomas P J; Metcalf, James S; Acero, Juan L; von Gunten, Urs

    2007-08-01

    As the World Health Organization (WHO) progresses with provisional Drinking Water Guidelines of 1 microg/L for microcystin-LR and a proposed Guideline of 1 microg/L for cylindrospermopsin, efficient treatment strategies are needed to prevent cyanotoxins such as these from reaching consumers. A kinetic database has been compiled for the oxidative treatment of three cyanotoxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), and anatoxin-a (ANTX) with ozone, chlorine, chlorine dioxide and permanganate. This kinetic database contains rate constants not previously reported and determined in the present work (e.g. for permanganate oxidation of ANTX and chlorine dioxide oxidation of CYN and ANTX), together with previously published rate constants for the remaining oxidation processes. Second-order rate constants measured in pure aqueous solutions of these toxins could be used in a kinetic model to predict the toxin oxidation efficiency of ozone, chlorine, chlorine dioxide and permanganate when applied to natural waters. Oxidants were applied to water from a eutrophic Swiss lake (Lake Greifensee) in static-dose testing and dynamic time-resolved experiments to confirm predictions from the kinetic database, and to investigate the effects of a natural matrix on toxin oxidation and by-product formation. Overall, permanganate can effectively oxidize ANTX and MC-LR, while chlorine will oxidize CYN and MC-LR and ozone is capable of oxidizing all three toxins with the highest rate. The formation of trihalomethanes (THMs) in the treated water may be a restriction to the application of sufficiently high-chlorine doses.

  17. STUDY OF THE EFFECT OF CHLORINE ADDITION ON MERCURY OXIDATION BY SCR CATALYST UNDER SIMULATED SUBBITUMINOUS COAL FLUE GAS

    Science.gov (United States)

    An entrained flow reactor is used to study the effect of addition of chlorine-containing species on the oxidation of elemental mercury (Hgo)by a selective catalytic reduction (SCR) catalyst in simulated subbituminous coal combustion flue gas. The combustion flue gas was doped wit...

  18. Comparative efficacy of chlorine and chlorine dioxide regimes for condenser slime control in seawater cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, P.S.; Veeramani, P.; Ershath, M.; Rajamohan, R.; Harinath, Y.V.; Mohan, T.V.K.; Venugopalan, V.P. [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamil nadu (India)

    2010-07-01

    Chlorination has long been used as an effective and economic biocide for biofouling control in seawater cooling systems. However, the efficacy of chlorine is reduced in the presence of organic content of seawater and the inability of chlorine to effectively penetrate biofilms. Chlorine dioxide is being projected as a possible alternative to chlorine. Experiments were carried out with the help of a seawater circulating facility, in which direct comparison of the efficacy of the two biocides was possible using test condenser tube assemblies. The test condenser tubes made of titanium, SS 316L and Cu-Ni 90/10 were dosed with chlorine and chlorine dioxide. Each dose was evaluated for 30 days. Continuous and intermittent additions of chlorine (0.38 - 0.45 mg L{sup -1} TRO) and chlorine dioxide (0.4 - 0.5 mg L{sup -1}) were used, along with control. The flow velocity in the tubes was maintained at 1.5 m/s. Results of the study showed that the efficacy of the biocide to control biofilms depended on the biocide and the material. Continuous chlorination resulted in 75% reduction of viable counts on titanium, followed by 24% reduction on CuNi and 6% reduction on SS 316L surfaces, as compared to the control. When compared to continuous chlorination, increase in bacterial density in the tubes was observed at different regimes of intermittent chlorination. On SS 316L and Cu-Ni surfaces, intermittent chlorination for 1h, once every 3 h, appeared to give adequate protection. Continuous addition of chlorine dioxide resulted in 99% reduction of viable counts on titanium surfaces, followed by 28% reduction on SS 316 L surfaces and 52% reduction on Cu-Ni surfaces, as compared to the controls. The data indicate that the efficacy of biocides to control biofilms depend on not only the biocide and its frequency of application but also the material of construction. (author)

  19. Chlorine hazard evaluation for the zinc-chlorine electric vehicle battery. Final technical report. [50 kWh

    Energy Technology Data Exchange (ETDEWEB)

    Zalosh, R. G.; Bajpai, S. N.; Short, T. P.; Tsui, R. K.

    1980-04-01

    Hazards associated with conceivable accidental chlorine releases from zinc-chlorine electric vehicle batteries are evaluated. Since commercial batteries are not yet available, this hazard assessment is based on both theoretical chlorine dispersion models and small-scale and large-scale spill tests with chlorine hydrate (which is the form of chlorine storage in the charged battery). Six spill tests involving the chlorine hydrate equivalent of a 50-kWh battery indicate that the danger zone in which chlorine vapor concentrations intermittently exceed 100 ppM extends at least 23 m directly downwind of a spill onto a warm (30 to 38/sup 0/C) road surface. Other accidental chlorine release scenarios may also cause some distress, but are not expected to produce the type of life-threatening chlorine exposures that can result from large hydrate spills. Chlorine concentration data from the hydrate spill tests compare favorably with calculations based on a quasi-steady area source dispersion model and empirical estimates of the hydrate decomposition rate. The theoretical dispersion model was combined with assumed hydrate spill probabilities and current motor vehicle accident statistics in order to project expected chlorine-induced fatality rates. These calculations indicate that expected chlorine fataility rates are several times higher in a city such as Los Angeles with a warm and calm climate than in a colder and windier city such as Boston. Calculated chlorine-induced fatality rate projections for various climates are presented as a function of hydrate spill probability in order to illustrate the degree of vehicle/battery crashworthiness required to maintain chlorine-induced fatality rates below current vehicle fatality rates due to fires and asphyxiations. 37 figures, 19 tables.

  20. Reductive dechlorination of chlorinated ethenes by iron metal and iron sulfide minerals

    Energy Technology Data Exchange (ETDEWEB)

    Sivavec, T.M.; Horney, D.P.; Baghel, S.S. [GE Corporate Research and Development, Schenectady, NY (United States)

    1995-12-31

    Reduced forms of iron and sulfur, such as Fe(II), iron(II) sulfide and hydrogen sulfide, are abundant natural reductants in anaerobic soils and sediments. Redox reactions between these reductants and organic pollutants are often greatly accelerated in natural systems because of microbial mediation or because the electron transfer is mediated by the cycling of Fe(II)/Fe(III). For example, recent studies have shown that surface-bound, reduced iron species play the important role of electron transfer mediator in reductions promoted by iron-reducing bacteria. It has been postulated that the reduction of chlorinated hydrocarbons by iron metal may occur by a reaction of surface-bound Fe(II) at the iron metal-water interface. The surface-bound Fe(II) species at the passive oxide-water interface may serve as mediator for the transfer of electrons from Fe{sup 0} to adsorbed chlorinated hydrocarbon. Fast reduction rates for chlorinated hydrocarbons observed in this system may be attributed to the facile regeneration of reducing surface Fe(II) species due to the close proximity of the bulk reductant (Fe{sup 0}) to the electron carrier, surface-bound Fe(II). Evidence in support of this proposed mechanism is presented.

  1. Lipid signaling in plants

    NARCIS (Netherlands)

    Munnik, T.

    2010-01-01

    This book highlights the current status of plant lipid signaling. Written by leading researchers in the field, the chapters include detailed information on the measurement, regulation and function of phospholipases, lipid kinases, lipid phosphatases, inositolpolyphosphates, polyphosphoinositides, ph

  2. Lipid Metabolism Disorders

    Science.gov (United States)

    ... metabolic disorder, something goes wrong with this process. Lipid metabolism disorders, such as Gaucher disease and Tay-Sachs disease, involve lipids. Lipids are fats or fat-like substances. They ...

  3. Plant lipid signaling protocols

    NARCIS (Netherlands)

    Munnik, T.; Heilmann, I.

    2013-01-01

    Eukaryotic cells are surrounded by membranes consisting of various lipids, including sterols, sphingolipids, glycolipids, and phospholipids. Besides structural functions, membranes also contain lipids with regulatory and signaling roles. Such lipids include polyphosphoinositides, the low-abundant

  4. UV/chlorine as an advanced oxidation process for the degradation of benzalkonium chloride: Synergistic effect, transformation products and toxicity evaluation.

    Science.gov (United States)

    Huang, Nan; Wang, Ting; Wang, Wen-Long; Wu, Qian-Yuan; Li, Ang; Hu, Hong-Ying

    2017-05-01

    Benzalkonium chlorides (BACs), as typical cationic surfactants and biocides widely applied in household and industrial products, have been frequently detected as micropollutants in many aquatic environments. In this study, the combination of UV irradiation and chlorine (UV/chlorine), a newly interested advanced oxidation process, was used to degrade dodecylbenzyldimethylammonium chloride (DDBAC). UV/chlorine showed synergistic effects on DDBAC degradation comparing to UV irradiation or chlorination alone. Radical quenching experiments indicated that degradation of DDBAC by UV/chlorine involved both UV photolysis and radical species oxidation, which accounted for 48.4% and 51.6%, respectively. Chlorine dosage and pH are essential parameters affecting the treatment efficiency of UV/chlorine. The pseudo first order rate constant (kobs, DDBAC) increased from 0.046 min(-1) to 0.123 min(-1) in response to chlorine dosage at 0-150 mg/L, and the degradation percentage of DDBAC within 12 min decreased from 81.4% to 56.6% at pH 3.6-9.5. Five main intermediates were identified and semi-quantified using HPLC-MS/MS and a possible degradation pathway was proposed. The degradation mechanisms of DDBAC by UV/chlorine included cleavage of the benzyl-nitrogen bond and hydrogen abstraction of the alkyl chain. Trichloromethane (TCM), chloral hydrate (CH), trichloropropanone (TCP), dichloropropanone (DCP) and dichloroacetonitrile (DCAN) were detected using GC-ECD. The formation of chlorinated products increased rapidly initially, then decreased (TCM, TCP, DCP and DCAN) or remained stable (CH) with extended treatment. The actual formation of TCM peaked at 30 min (50.3 μg/L), while other chlorinated products did not exceed 10 μg/L throughout the process. Based on the luminescent bacterial assay, DDBAC solution underwent almost complete detoxification subjected to UV/chlorine treatment for 120 min, which is more effective than UV irradiation or chlorination alone.

  5. Revisiting the thermochemistry of chlorine fluorides

    CERN Document Server

    Sánchez, H R

    2016-01-01

    In this work, accurate calculations of standard enthalpies of formation of chlorine fluorides (ClF$_n$, n=1--7; Cl$_2$F and Cl$_3$F$_2$) were performed through the isodesmic reactions scheme. It is argued that, for many chlorine fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not capable to predict enthalpy values nearing chemical accuracy if atomization scheme is used. This is underpinned by a thorough analysis of total atomization energy results and the inspection of multireference features of these compounds. Other thermodynamic quantities were also calculated at different temperatures. In order to complement the energetic description, elimination curves were studied through density functional theory as a computationally affordable alternative to highly correlated wave function-based methods.

  6. Behavioral toxicology, risk assessment, and chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista de Duffard, A.M.; Duffard, R. [Laboratorio de Toxicologia Experimental, Santa Fe (Argentina)

    1996-04-01

    Behavioral end points are being used with greater frequency in neurotoxicology to detect and characterize the adverse effects of chemicals on the nervous system. Behavioral measures are particularly important for neurotoxicity risk assessment since many known neurotoxicants do not result in neuropathology. The chlorinated hydrocarbon class consists of a wide variety of chemicals including polychlorinated biphenyls, clioquinol, trichloroethylene, hexachlorophene, organochlorine insecticides (DDT, dicofol, chlordecone, dieldrin, and lindane), and phenoxyherbicides. Each of these chemicals has effects on motor, sensory, or cognitive function that are detectable using functional measures such as behavior. Furthermore, there is evidence that if exposure occurs during critical periods of development, many of the chlorinated hydrocarbons are developmental neurotoxicants. Developmental neurotoxicity is frequently expressed as alterations in motor function or cognitive abilities or charges in the ontogeny of sensorimotor reflexes. Neurotoxicity risk assessment should include assessments of the full range of possible neurotoxicological effects, including both structural and functional indicators of neurotoxicity. 121 refs., 1 tab.

  7. Chlorine decay and trihalomethane formation following ferrate(VI) preoxidation and chlorination of drinking water.

    Science.gov (United States)

    Li, Cong; Luo, Feng; Dong, Feilong; Zhao, Jingguo; Zhang, Tuqiao; He, Guilin; Cizmas, Leslie; Sharma, Virender K

    2017-08-19

    This paper presents the effect of preoxidation with ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) prior to chlorination on chlorine decay and formation of disinfection by-products in filtered raw water from a full-scale drinking water treatment plant. The rate of chlorine decay became significantly faster as the concentration of ferrate(VI) increased. Chlorine degradation followed two first-order decay reactions with rate constants k1 and k2 for fast and slow decay, respectively. Kinetic modeling established the relationships between k1 and k2 and varying dosages of chlorine and ferrate(VI). When ferrate(VI) was used as a pre-oxidant, the levels of trihalomethanes (trichloromethane (TCM), dichlorobromomethane (DCBM), dibromochloromethane (DBCM), and tribromomethane (TBM)) in water samples decreased as the ferrate(VI) concentration increased. The concentrations of these trihalomethanes followed the order TCM > DCBM ≈ DBCM > TBM. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Thermal diffusion of chlorine in uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Pipon, Y.; Toulhoat, N.; Moncoffre, N.; Jaffrezic, H.; Gavarini, S. [Inst. de Physique Nucleaire de Lyon (IPNL), Villeurbanne (France); Martin, P. [Commissariat a l' Energie Atomique (CEA), Centre de Cadarache, DEN/DEC/SESC/LLCC, Saint-Paul lez Durance (France); Raimbault, L. [Centre d' Informatique Geologique (CIG), Ecole des Mines, Fontainebleau (France); Scheidegger, A.M. [Lab. for Waste Management, Nuclear Energy and Safety Dept. (NES), Paul Scherrer Inst. Villigen PSI (Switzerland)

    2006-07-01

    In a nuclear reactor, isotopes such as {sup 35}Cl present as impurities in the nuclear fuel are activated by thermal neutron capture. During interim storage or geological disposal of nuclear fuel, the activation products such as {sup 36}Cl may be released from the fuel to the geo/biosphere and contribute to the ''instant release fraction'' as they are likely to migrate in defects and grain boundaries. In order to differentiate diffusion mechanisms due to ''athermal'' processes during irradiation from thermally activated diffusion, both irradiation and thermal effects must be assessed. This work concerns the measurement of the thermal diffusion coefficient of chlorine in UO{sub 2}. {sup 37}Cl was implanted at a 10{sup 13} at/cm{sup 2} fluence in depleted UO{sub 2} samples which were then annealed in the 900-1200 C temperature range and finally analyzed by secondary ion mass spectrometry (SIMS) to obtain {sup 37}Cl depth profiles. The migration process appears to be rather complex, involving mechanisms such as atomic, grain boundary, directed diffusion along preferential patterns as well as trapping into sinks before successive effusion. However, using a diffusion model based on general equation of transport, apparent diffusion coefficients could be calculated for 1000 and 1100 C and a mean activation energy of 4.3 eV is proposed. This value is one of the lowest values compared to those found in literature for other radionuclides pointing out a great ability of chlorine to migrate in UO{sub 2} at relatively low temperatures. In order to unequivocally determine the diffusion behaviour of both implanted and pristine chlorine before and after thermal annealing, the structural environment of chlorine in UO{sub 2} was examined using micro X-ray fluorescence (micro-XRF) and micro X-ray absorption spectroscopy (micro-XAS). (orig.)

  9. Report on the chlorine solar neutrino experiment.

    Science.gov (United States)

    Davis, R., Jr.; Lande, K.; Cleveland, B. T.; Ullman, J.; Rowley, J. K.

    New results from the chlorine solar neutrino experiment are presented. Observations of the solar neutrino flux over the period 1970 to 1988 show an average 37Ar production rate of 2.33±0.25 SNU. The 37Ar production rate exhibits an apparent anti-correlation with the solar activity cycle. The current measurements (1986 - 1988) made during minimum solar activity give an 37Ar production rate of 4.2±0.8 SNU.

  10. The gas phase chlorination of ethane

    Energy Technology Data Exchange (ETDEWEB)

    Olsbye, Unni; Myhrvold, Elisabeth M.; Slagtern, Aase; Dahl, Ivar M. [SINTEF Applied Chemistry, Oslo (Norway)

    1999-07-01

    Light alkanes are dehydrogenated to their corresponding olefins before further reactions to more valuable chemicals. The conversion of ethane to ethene in a steam cracker requires the addition of a substantial amount of heat (90 kJ/mol). Oxidative processes for ethane dehydrogenation could in principle be carried out adiabatically, however, the oxidation selectivity towards hydrogen is too low in existing systems, which leads to low ethene selectivities. This paper discusses the potential for light alkane derivatization through chlorination.

  11. Hydraulic fracturing with chlorine dioxide cleanup

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.A.; Newlove, J.C.; Horton, R.L.

    1990-10-23

    This patent describes a method for fracturing a subterranean formation penetrated by a wellbore. It comprises: injecting a fracturing fluid into the formation to form a vertical fracture therein, the fracturing fluid being gelled with a polymer selected from guar, guar derivatives, acrylamide, acrylamide derivatives, cellulose, cellulose derivatives, and mixtures thereof and crosslinked with an organometallic crosslinking compound and having temperature stability above about 175{degrees} F.; packing the fracture with particulate propping agent; backflowing fluids from the formation through the propped fracture to remove a portion of the polymer; injecting at matrix rates sufficient aqueous solution of chlorine dioxide down the wellbore and into the propped fracture to penetrate at least 60 feet of the propped fracture length and contact polymer in the fracturing fluid and polymer residue in the propped fracture and on the fracture walls, the amount of the chlorine dioxide in the aqueous medium being sufficient to degrade polymer in the fracturing fluid and polymer residue; permitting the chlorine dioxide to remain in contact with the polymer in the fracturing fluid and with the polymer residue on the fracture walls and in the fracture for sufficient time to degrade the polymer thereby reducing the fracturing fluid viscosity and dissolving portions of the polymer residue; and flowing formation fluid from the formation through the propped fracture and into the wellbore to remove substantial portions of the polymer and degraded polymer from the fracture.

  12. Chlorine Monoxide in the Antarctic Spring Stratosphere.

    Science.gov (United States)

    Jaramillo-Ayerbe, Mauricio

    1988-06-01

    A series of observations of stratospheric chlorine monoxide (ClO) were carried out during the austral springs of 1986 and 1987 in McMurdo Station, Antarctica, as part of two experimental campaigns sent to investigate the seasonal decrease in ozone over the antarctic continent (the ozone "hole"). Measurements of the vertical distribution of ClO were obtained by high resolution ground-based emission spectroscopy at 278 GHz, using the Stony Brook mm-wave receiver. They show the presence of an anomalous layer of lower stratospheric ClO which is not observed at other latitudes. This anomalous layer is centered at ~20 km altitude and exhibits a pronounced diurnal variation, reaching a maximum at midday and disappearing at night. During the period of Sep. 20-24, 1987, the lower-stratospheric ClO had a maximum volume mixing ratio of 1.8_sp{+0cdot5}{ -0cdot9} ppbv. A normal ClO layer centered at ~36 km was also observed, with concentrations and diurnal behavior similar to those seen in tropical latitudes. These findings are evidence of anomalous chlorine chemistry taking place in the lower stratosphere during the antarctic spring, and indicate that increasing anthropogenic chlorine is a prime causative agent in the formation of the ozone hole.

  13. Monitoring the trihalomethanes present in water after treatment with chlorine under laboratory condition.

    Science.gov (United States)

    Paim, A P S; Souza, J B; Adorno, M A T; Moraes, E M

    2007-02-01

    In this work assays involving chlorinated water samples, which were previous spiked with humic substances or algae blue green and following the production of the THMs for 30 days is described. To implement the assays, five portions of 1,000 ml of water were stored in glass bottles. The water samples were treated with solutions containing 2, 3, 4 and 5 mg l(-1) chlorine. The samples aliquots (60 ml) were transferred into the glass vials, 10 ml were removed to have a headspace and 100 microl of the 10 mg l(-1) pentafluortoluene bromide solution was added to each vial. The extraction step was performed by adding 10 g of Na(2)SO(4) followed by 5 ml of n-pentane. The vials were stopped with a TFE-faced septum and sealed with aluminum caps. The generated THMs were determined by gas chromatography with electron capture detector using reference solutions with concentration ranging from 8 to 120 microg l(-1) THMs. Three assays were monitored during 30 days and chloroform was the predominant compound found in the water samples, while other species of THMs were not detected. The results showed that when the chlorine concentration was increased in water samples containing algae the concentration of THM varied randomly. Nevertheless, in water samples containing humic substances the increase of the THM concentration presented a relationship with the chlorine concentration. It was also observed that chloroform concentration increased with the elapsed time up to one and six days to water samples spiked with humic substances and algae blue green, respectively and decreased along 30 days. By other hand, assays performed using water samples containing decanted algae material showed that THM was not generated by the chlorine addition.

  14. Non-enzymatically derived minor lipids found in Escherichia coli lipid extracts.

    Science.gov (United States)

    Garrett, Teresa A; Raetz, Christian R H; Son, Jennifer D; Richardson, Travis D; Bartling, Craig; Guan, Ziqiang

    2011-11-01

    Electrospray ionization mass spectrometry is a powerful technique to analyze lipid extracts especially for the identification of new lipid metabolites. A hurdle to lipid identification is the presence of solvent contaminants that hinder the identification of low abundance species or covalently modify abundant lipid species. We have identified several non-enzymatically derived minor lipid species in lipid extracts of Escherichia coli; phosphatidylmethanol, ethyl and methyl carbamates of PE and N-succinyl PE were identified in lipid extracts of E. coli. Phosphatidylmethanol (PM) was identified by exact mass measurement and collision induced dissociation tandem mass spectrometry (MS/MS). Extraction in the presence of deuterated methanol leads to a 3 atomic mass unit shift in the [M-H](-) ions of PM indicating its formation during extraction. Ethyl and methyl carbamates of PE, also identified by exact mass measurement and MS/MS, are likely to be formed by phosgene, a breakdown product of chloroform. Addition of phosgene to extractions containing synthetic PE significantly increases the levels of PE-MC detected in the lipid extracts by ESI-MS. Extraction in the presence of methylene chloride significantly reduced the levels of these lipid species. N-succinyl PE is formed from reaction of succinyl-CoA with PE during extraction. Interestingly N-succinyl PE can be formed in an aqueous reaction mixture in the absence of added E. coli proteins. This work highlights the reactivity of the amine of PE and emphasizes that careful extraction controls are required to ensure that new minor lipid species identified using mass spectrometry are indeed endogenous lipid metabolites.

  15. Electric plasma discharge combustion synthesis of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Dotson, R. L.; Geren, G. W.

    1984-09-18

    A process for the production of chlorine dioxide comprises feeding an inert gas to a reaction zone and applying an electrical discharge to the inert gas to produce a high temperature plasma. Chlorine gas and oxygen gas are supplied simultaneously to the reaction zone and reacted in the plasma to produce a gaseous mixture comprised of chlorine dioxide, chlorine, oxygen and inert gas, the molar ratio of oxygen to chlorine in the reaction zone being at least about 2.5;1. The gaseous mixture is recovered from the reaction zone. Chlorine dioxide, which may be recovered as a gas or reacted to produce an alkali metal chlorite, is employed as a bleaching agent and a water treatment agent.

  16. Disinfection efficacy of chlorine and peracetic acid alone or in combination against Aspergillus spp. and Candida albicans in drinking water.

    Science.gov (United States)

    Sisti, Maurizio; Brandi, Giorgio; De Santi, Mauro; Rinaldi, Laura; Schiavano, Giuditta F

    2012-03-01

    The aim of the present study was to evaluate the fungicidal activity of chlorine and peracetic acid in drinking water against various pathogenic Aspergillus spp. and Candida albicans strains. A. nidulans exhibited the greatest resistance, requiring 10 ppm of chlorine for 30 min contact time for a complete inactivation. Under the same experimental conditions, peracetic acid was even less fungicidal. In this case, A. niger proved to be the most resistant species (50 ppm for 60 min for complete inactivation). All Aspergillus spp. were insensitive to 10 ppm even with extended exposure (>5 h). The combination of chlorine and peracetic acid against Aspergillus spp. did not show synergistic effects except in the case of A. flavus. Complete growth inhibition of C. albicans was observed after about 3 h contact time with 0.2 ppm. C. albicans was less sensitive to peracetic acid. Hence the concentrations of chlorine that are usually present in drinking water distribution systems are ineffective against several Aspergillus spp. and peracetic acid cannot be considered an alternative to chlorine for disinfecting drinking water. The combination of the two biocides is not very effective in eliminating filamentous fungi at the concentrations permitted for drinking water disinfection.

  17. Formation potentials of typical disinfection byproducts and changes of genotoxicity for chlorinated tertiary effluent pretreated by ozone.

    Science.gov (United States)

    Cao, Nan; Miao, Tingting; Li, Kuixiao; Zhang, Yu; Yang, Min

    2009-01-01

    The effects of ozonation on the formation potential of typical disinfection byproducts (DBPs) and the changes of genotoxicity during post chlorination of tertiary effluent from a sewage treatment plant were investigated. Ozonation enhanced the yields of all detected chlorine DBPs except CHCl3. At a chlorine dose of 5 mg/L, the three brominated THMs and five HAAs increased, while chloroform decreased with the increase of ozone dose from 0 to 10 mg/L (ozone dose in consumption base). At a chlorine dose of 10 mg/L, the two mixed bromochloro species THMs and two dominant HAAs (DCAA and TCAA) increased firstly and then decreased with the increase of ozone dose, with the turning point approximately occurring at an ozone dose of 5 mg/L. The genotoxicity detected using umu test, on the other hand, was removed from 7 microg 4-NQO/L to a negligible level by ozonation under an ozone dose of 5 mg/L. Chlorination could further remove the genotoxicity to some extent. It was found that SUVA (UV absorbance divided by DOC concentration) might be used as an indicative parameter for monitoring the removal of genotoxicity during the oxidation.

  18. Enhancement of photocatalytic activity of TiO2 film electrode by in situ photoelectro-generating active chlorine

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The photoelectrocatalytic activity of TiO2 film electrodes in the degradation of nitrite ion was greatly enhanced in the presence of chlorine ion. The influences of NaCl concentration and initial pH value on the degradation rate of NO2- and active chlorine production were studied. The results show that the decay rate of NO2- and the accumulation rate of active chlorine increase with increasing NaCl concentration. At pH<8, both the decay of NO2- and active chlorine formation rates are enhanced with increasing NaCl concentration, while at pH> 10, they are suppressed. In addition, contrast to conventionally accepted view, in which an advantage of anatase over the rutile modification of TiO2 is in terms of photoactivity, it is found that a thermal oxidation rutile TiO2 electrode is more suitable for both photogenerating active chlorine and degrading NO2- in the presence of Cl-. The correlative mechanism was also discussed in detail. Specific adsorption of Cl- on the electrode causes its energy band edges to move towards positive value and also lower the photocurrent,thus less OH· radicals are produced. However,more active species of Cl· that have longer lifetime are available to take part in the oxidation of NO2-, thus improving its degradation rate.

  19. Method of improving formation permeability using chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, L.A.; Williams, D.A.

    1991-07-16

    This patent describes a method of treating a sandstone formation containing clays or silicates. It comprises injection a treating liquid into the formation comprising an aqueous solution of: from 50 to 4,200 ppm chlorine dioxide and from 1 to 85 volume percent of carbon dioxide; permitting the chlorine dioxide to react with material in the formation; and thereafter injecting into the formation an acid solution capable of dissolving the reaction products of chlorine dioxide and the clays and silicates.

  20. The removal of phenols from oily wastewater by chlorine dioxide

    OpenAIRE

    Hsu, Chung-Jung

    1988-01-01

    Treatability studies were performed on oily wastewaters produced by petroleum and canning industries. Chlorine dioxide was used for the removal of phenolic compounds from these oily wastewaters. Most of phenolic compounds can be destroyed by chlorine dioxide within 15 minutes if CI02-to-phenol ratios of higher than 5.0 are provided. Factors such as pH, temperature, and COD have little effect on phenol removal. The effectiveness of chlorine dioxide treatment depends critic...

  1. Predicting bromide incorporation in a chlorinated indoor swimming pool.

    Science.gov (United States)

    Chowdhury, Shakhawat; Mazumder, Abu Jafar; Husain, Tahir

    2016-06-01

    The water in and air above swimming pools often contain high levels of disinfection byproducts (DBPs) due to chemical reactions between chlorine- or bromine-based disinfectants and organic/inorganic matter in the source water and released from swimmers. Exposure to these DBPs, though inevitable, can pose health threats to humans. In this study, DBPs in tap water (S1), and water from a chlorinated indoor swimming pool before (S2) and after swimming (S3) were measured. The brominated species constituted the majority of DBPs formed in S1, S2, and S3. Trihalomethanes (THMs) in S3 was 6.9 (range 2.9-11.1) and 1.4 (range 0.52-2.9) times those in S1 and S2, respectively; and the haloacetic acids (HAAs) in S3 was 4.2 (range 2.5-7.5) and 1.2 (range 0.6-2.6) times those in S1 and S2, respectively. The mean THMs in air above the swimming pool before (S2-A) and after swimming (S3-A) were 72.2 and 93.0 μg/m(3), respectively, and their ranges were 36.3-105.8 and 44.1-133.6 μg/m(3), respectively. The average percentages of bromide incorporation (BI) into THMs in S1, S2, and S3 were 3.0, 9.3, and 10.6 %, respectively; and the BI into HAAs in S1, S2, and S3 were 6.6, 12.0, and 12.2 %, respectively. Several models were trained for predicting the BI into THMs and HAAs. The results indicate that additional information is required to develop predictive models for BI in swimming pools.

  2. Treatment of algae-induced tastes and odors by chlorine, chlorine dioxide and permanganate

    OpenAIRE

    Buffin, Lisa Webster

    1992-01-01

    Chlorine (C12(sq»' chlorine dioxide (Cl02 ) and potassium permanganate (KMn04) were evaluated as oxidants for the removal of grassy and cucumber odors associated with the pure compounds, cis-3-hexenol and trans-2, cis-6-nonadienal, respectively, and for the removal of fishy odors associated with a culture of an alga, Synura petersenii. The effects of the oxidants on the pure compounds were assessed both by Flavor Profile Analysis (FPA) and gas chromatography/mass spectrometry (GC/MS). The ef...

  3. Cyclopalladated Ferrocenylimine Catalyzed Chlorination of 2-Arylbenzoxazoles%Cyclopalladated Ferrocenylimine Catalyzed Chlorination of 2-Arylbenzoxazoles

    Institute of Scientific and Technical Information of China (English)

    冷瑜婷; 杨帆; 吴养洁; 李克

    2011-01-01

    An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlori- nation was not a ligand-directed ortho-C--H activation, but an electrophilic substitution process at the para-position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.

  4. Carbon and chlorine isotopologue fractionation of chlorinated hydrocarbons during diffusion in water and low permeability sediments

    Science.gov (United States)

    Wanner, Philipp; Hunkeler, Daniel

    2015-05-01

    To identify reactive processes in diffusion dominated water-saturated systems using compound-specific isotope analysis (CSIA), the effect of the diffusive transport process on isotope ratios needs to be known. This study aims to quantify the magnitude of carbon and chlorine isotopologue fractionation of two chlorinated hydrocarbons (trichloroethene (TCE) and 1,2-dichloroethane (1,2-DCA)) during diffusion in the aqueous phase and to relate for the first time laboratory with field results. Diffusion coefficient ratios in the aqueous phase were experimentally quantified with a modified Stokes diffusion cell. The experiment revealed a significant shift of carbon and chlorine isotopologue ratios of TCE and 1,2-DCA during diffusion. For both TCE and 1,2-DCA, the magnitude of the shift of chlorine isotopologue ratios was larger (TCE: D132/D130 = 0.99963 ± 0.00003; 1,2-DCA: D102/D100 = 0.99939 ± 0.00003) in comparison to carbon isotopologue ratios (TCE: D131/D130 = 0.99978 ± 0.00006; 1,2-DCA: D101/D100 = 0.99977 ± 0.00004), which is consistent with the larger mass difference between stable chlorine compared to carbon isotopes. Determined diffusion coefficients for carbon and chlorine isotopologues of TCE and 1,2-DCA follow an inverse power law form (D ∝m-β) with β < 0.5 revealing that the magnitude of isotopologue fractionation of TCE and 1,2-DCA is lower than in the previously postulated kinetic theory (D ∝m-0.5). To relate laboratory with field results, a water-saturated clay core from a VOC contaminated site was retrieved and subsampled as a function of depth to assess possible shifts in isotopologue ratios during downward diffusion of VOCs into the low permeable clay. Observed small shifts of TCE carbon and chlorine isotopologue ratio profiles were consistent with laboratory determined diffusion coefficient ratios, demonstrated by a 1D-diffusion model. Further 1D-simulations for shorter diffusion periods (5-10 years) than observed in the retrieved clay core

  5. Mechanisms of inactivation of poliovirus by chlorine dioxide and iodine.

    OpenAIRE

    Alvarez, M.E.; O'Brien, R.T.

    1982-01-01

    Chlorine dioxide and iodine inactivated poliovirus more efficiently at pH 10.0 than at pH 6.0. Sedimentation analyses of viruses inactivated by chlorine dioxide and iodine at pH 10.9 showed that viral RNA separated from the capsids, resulting in the conversion of virions from 156S structures to 80S particles. The RNAs release from both chlorine dioxide- and iodine-inactivated viruses cosedimented with intact 35S viral RNA. Both chlorine dioxide and iodine reacted with the capsid proteins of p...

  6. High levels of molecular chlorine in the Arctic atmosphere

    Science.gov (United States)

    Liao, Jin; Huey, L. Gregory; Liu, Zhen; Tanner, David J.; Cantrell, Chris A.; Orlando, John J.; Flocke, Frank M.; Shepson, Paul B.; Weinheimer, Andrew J.; Hall, Samuel R.; Ullmann, Kirk; Beine, Harry J.; Wang, Yuhang; Ingall, Ellery D.; Stephens, Chelsea R.; Hornbrook, Rebecca S.; Apel, Eric C.; Riemer, Daniel; Fried, Alan; Mauldin, Roy L.; Smith, James N.; Staebler, Ralf M.; Neuman, J. Andrew; Nowak, John B.

    2014-02-01

    Chlorine radicals can function as a strong atmospheric oxidant, particularly in polar regions, where levels of hydroxyl radicals are low. In the atmosphere, chlorine radicals expedite the degradation of methane and tropospheric ozone, and the oxidation of mercury to more toxic forms. Here we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We report high levels of molecular chlorine, of up to 400 pptv. Concentrations peaked in the early morning and late afternoon, and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone are required for molecular chlorine formation. Using a time-dependent box model, we estimate that the chlorine radicals produced from the photolysis of molecular chlorine oxidized more methane than hydroxyl radicals, on average, and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyses mercury oxidation and the breakdown of tropospheric ozone. We therefore suggest that molecular chlorine exerts a significant effect on the atmospheric chemistry of the Arctic.

  7. Effect of ferric and bromide ions on the formation and speciation of disinfection byproducts during chlorination

    Institute of Scientific and Technical Information of China (English)

    Shaogang Liu; Zhiliang Zhu; Yanling Qiu; Jianfu Zhao

    2011-01-01

    The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts (DBPs) during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower content of total organic carbon (TOC) and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions,four trihalomethanes (THMs), nine haloacetic acids (HAAs), total organic halogen (TOX) and its halogen species fractions, including total organic chlorine (TOC1) and total organic bromide (TOBr), were determined. The results showed that co-existent ferric and bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species,which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide ions in raw water samples produced higher percentages of unknown TOBr.

  8. Effect of ferric and bromide ions on the formation and speciation of disinfection byproducts during chlorination.

    Science.gov (United States)

    Liu, Shaogang; Zhu, Zhiliang; Qiu, Yanling; Zhao, Jianfu

    2011-01-01

    The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts (DBPs) during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower content of total organic carbon (TOC) and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions, four trihalomethanes (THMs), nine haloacetic acids (HAAs), total organic halogen (TOX) and its halogen species fractions, including total organic chlorine (TOC1) and total organic bromide (TOBr), were determined. The results showed that co-existent ferric and bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species, which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide ions in raw water samples produced higher percentages of unknown TOBr.

  9. Hybrid Lipid as Biological Surfactants

    Science.gov (United States)

    Brewster, Robert; Pincus, Phil; Safran, Sam

    2009-03-01

    Systems capable of forming finite-sized, equilibrium domains are of biological interest in the context of membrane rafts where it has been observed that certain cellular functions are mediated by small (nanometric to tens of nanometers) domains with specific lipid composition that differs from the average composition of the membrane. These small domains are composed mainly of lipids with completely saturated hydrocarbon tails that show good orientational order in the membrane. The surrounding phase consists mostly of lipids with at least one unsaturated bond in the hydrocarbon tails which forces a ``kink'' in the chain and inhibits ordering. In vitro, this phase separation can be replicated; however, the finite domains coarsen into macroscopic domains with time. We have extended a model for the interactions of lipids in the membrane, akin to that developed in the group of Schick (Elliott et al., PRL 2006 and Garbes Putzel and Schick, Biophys. J. 2008), which depends entirely on the local ordering of hydrocarbon tails. We generalize this model to an additional species and identify a biologically relevant component, a lipid with one fully saturated hydrocarbon chain and one chain with at least one unsaturated bond, that may serve as a line-active component, capable of reducing the line tension between domains to zero, thus stabilizing finite sized domains in equilibrium.

  10. Removal of endocrine disruptors and non-steroidal anti-inflammatory drugs through wastewater chlorination: the effect of pH, total suspended solids and humic acids and identification of degradation by-products.

    Science.gov (United States)

    Noutsopoulos, Constantinos; Koumaki, Elena; Mamais, Daniel; Nika, Maria-Christina; Bletsou, Anna A; Thomaidis, Nikolaos S

    2015-01-01

    Endocrine disrupting chemicals (EDCs) and non-steroidal anti-inflammatory drugs (NSAIDs) are two groups of emerging pollutants the significance of which rests on their persistent detection in the aquatic environment and their possible adverse effects. Wastewater treatment plants are one of the major ways for transporting such chemicals in the aquatic environment. Chlorination is usually the last stage of treatment before wastewater being disposed to the aquatic environment. This work focuses on the evaluation of the effect of chlorine dose and specific wastewater characteristics (pH, total suspended solids and humic acids) on the removal of target EDCs and NSAIDs through chlorination. Another objective of this study is the identification of chlorination by-products of specific EDCs and NSAIDs and their dependence on contact time. Based on the results it is concluded that the effect of chlorine dose and humic acids concentration on the degradation of target compounds during chlorination is minimal. On the contrary, pH is a critical parameter which highly affects process performance. Moreover, it is concluded that not only the free available chlorine species, but also the properties of EDCs and NSAIDs under different pH conditions can affect chlorination process performance. The effect of TSS on the degradation of the target compounds during chlorination is more profound for chemicals with high Kow values and therefore higher affinity to partition to the particulate phase (i.e. nonylphenols, triclosan). Several degradation by-products were identified through chlorination of nonylphenol, bisphenol A and diclofenac. The dependence of these by-products on chlorination contact time is also demonstrated. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice.

    Science.gov (United States)

    Sasada, Tatsunari; Hinoi, Takao; Saito, Yasufumi; Adachi, Tomohiro; Takakura, Yuji; Kawaguchi, Yasuo; Sotomaru, Yusuke; Sentani, Kazuhiro; Oue, Naohide; Yasui, Wataru; Ohdan, Hideki

    2015-01-01

    The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc) knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma--caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc(+/flox), abbreviated to CPC;Apc) or microsatellite (CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox)) instability, respectively--were administered chlorinated (10.0 mg/L chlorine) or tap (0.7 mg/L chlorine) water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox) mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to differences

  12. Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice.

    Directory of Open Access Journals (Sweden)

    Tatsunari Sasada

    Full Text Available The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma--caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc(+/flox, abbreviated to CPC;Apc or microsatellite (CDX2P9.5-G19Cre;Apc(flox/flox and CDX2P9.5-G22Cre;Apc(flox/flox instability, respectively--were administered chlorinated (10.0 mg/L chlorine or tap (0.7 mg/L chlorine water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apc(flox/flox and CDX2P9.5-G22Cre;Apc(flox/flox mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to

  13. Electrodiffusion of lipids on membrane surfaces

    Science.gov (United States)

    Zhou, Y. C.

    2012-05-01

    Lateral translocation of lipids and proteins is a universal process on membrane surfaces. Local aggregation or organization of lipids and proteins can be induced when the random lateral motion is mediated by the electrostatic interactions and membrane curvature. Although the lateral diffusion rates of lipids on membranes of various compositions are measured and the electrostatic free energies of predetermined protein-membrane-lipid systems can be computed, the process of the aggregation and the evolution to the electrostatically favorable states remain largely undetermined. Here we propose an electrodiffusion model, based on the variational principle of the free energy functional, for the self-consistent lateral drift-diffusion of multiple species of charged lipids on membrane surfaces. Finite sizes of lipids are modeled to enforce the geometrical constraint of the lipid concentration on membrane surfaces. A surface finite element method is developed to appropriate the Laplace-Beltrami operators in the partial differential equations of the model. Our model properly describes the saturation of lipids on membrane surfaces, and correctly predicts that the MARCKS peptide can consistently sequester three multivalent phosphatidylinositol 4,5-bisphosphate lipids through its basic amino acid residues, regardless of a wide range of the percentage of monovalent phosphatidylserine in the membrane.

  14. High Levels of Molecular Chlorine found in the Arctic Atmosphere

    Science.gov (United States)

    Liao, J.; Huey, L. G.; Liu, Z.; Tanner, D.; Cantrell, C. A.; Orlando, J. J.; Flocke, F. M.; Shepson, P. B.; Weinheimer, A. J.; Hall, S. R.; Beine, H.; Wang, Y.; Ingall, E. D.; Thompson, C. R.; Hornbrook, R. S.; Apel, E. C.; Fried, A.; Mauldin, L.; Smith, J. N.; Staebler, R. M.; Neuman, J. A.; Nowak, J. B.

    2014-12-01

    Chlorine radicals are a strong atmospheric oxidant, particularly in polar regions where levels of hydroxyl radicals can be quite low. In the atmosphere, chlorine radicals expedite the degradation of methane and tropospheric ozone and the oxidation of mercury to more toxic forms. Here, we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We detected high levels of molecular chlorine of up to 400 pptv. Concentrations peaked in the early morning and late afternoon and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone are required for molecular chlorine formation. Using a time-dependent box model, we estimated that the chlorine radicals produced from the photolysis of molecular chlorine on average oxidized more methane than hydroxyl radicals and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyzed mercury oxidation and the breakdown of tropospheric ozone. Therefore, we propose that molecular chlorine exerts a significant effect on the atmospheric chemistry in the Arctic. While the formation mechanisms of molecular chlorine are not yet understood, the main potential sources of chlorine include snowpack, sea salt, and sea ice. There is recent evidence of molecular halogen (Br2 and Cl2) formation in the Arctic snowpack. The coverage and composition of the snow may control halogen chemistry in the Arctic. Changes of sea ice and snow cover in the changing climate may affect air-snow-ice interaction and have a significant impact on the levels of radicals, ozone, mercury and methane in the Arctic troposphere.

  15. Effects of chlorine and chlorine dioxide on mutagenic activity of Lake Kinnereth water

    Energy Technology Data Exchange (ETDEWEB)

    Guttman-Bass, N.; Bairey-Albuquerque, M.; Ulitzur, S.; Chartrand, A.; Rav-Acha, C.

    1987-03-01

    Water from Lake Kinnereth (Israel) was tested for the presence of mutagenic activity, with and without disinfection by chlorine and chlorine dioxide. The samples were assayed for activity with two Ames Salmonella typhimurium tester strains, TA 104 and TA 100, and by a luminescent genotoxic assay with a dark mutant strain of Photobacterium fischeri. The water concentrates were mutagenic in strain TA 104 and in the luminescent assay, reaching positive mutagenic activities in the equivalent of 20 mL of water. Chlorination did not greatly affect the net mutagenic activity, although ClO/sub 2/ apparently reduced it. Humic acids were isolated from lake sediment and were assayed with and without disinfection in distilled water and in lake water from which the organic components were removed. The humic acids were mutagenic in both test systems, and treatment with Cl/sub 2/ generally decreased the net activity. ClO/sub 2/ also tended to decrease the mutagenic activity, and cytotoxic effects were observed in some of the samples. Conversely, commercial humic acid was mutagenic only after chlorination on strain TA 100. 54 references, 3 figures, 6 tables.

  16. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    Science.gov (United States)

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii. PMID:21602398

  17. Skeletal and chlorine effects on 13C-NMR chemical shifts of chlorinated polycyclic systems

    Directory of Open Access Journals (Sweden)

    Costa V.E.U.

    1999-01-01

    Full Text Available In order to establish a comparative analysis of chemical shifts caused by ring compression effects or by the presence of a chlorine atom on strained chlorinated carbons, a series of the chlorinated and dechlorinated polycyclic structures derived from "aldrin" (5 and "isodrin" (14 was studied. Compounds were classified in four different groups, according to their conformation and number of ring such as: endo-exo and endo-endo tetracyclics, pentacyclics and hexacyclics. The 13C chemical shift comparison between the chlorinated and dechlorinated compounds showed that when C-9 and C-10 are olefinic carbons, it occurs a shielding of 0.5-2.4 ppm for endo-endo tetracyclics and of 4.7-7.6 ppm for endo-exo tetracyclic. The chemical shift variation for C-11 reaches 49-53 ppm for endo-exo and endo-endo tetracyclics, 54 ppm for pentacyclic and 56-59 ppm for hexacyclic compounds. From these data, it was possible to observe the influence of ring compression on the chemical shifts.

  18. Cellular response of the amoeba Acanthamoeba castellanii to chlorine, chlorine dioxide, and monochloramine treatments.

    Science.gov (United States)

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-07-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii.

  19. Scenarios Evaluation Tool for Chlorinated Solvent MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, Karen; Michael J. Truex; Charles J. Newell; Brian Looney

    2007-02-28

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  20. Advantages and disadvantages of chemical oxidation and disinfection by ozone and chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Fiessinger, F.; Richard, Y.; Montiel, A.; Musquere, P.

    1981-04-01

    Ozone and chlorine dioxide present definite advantages and disadvantages over chlorination. Chlorination, particularly for the removal of ammonia and the maintenance of a disinfectant residual in the distribution system has decisive advantages and will be difficult to replace. Ozone and chlorine dioxide seem to produce fewer carcinogenic by-products but the risk for acute toxicity, especially from the chlorites which follow chlorine dioxide, is higher than with chlorine. Chlorine dioxide and more particularly ozone should be considered as useful complements to chlorination, but no strong oxidative treatment should be applied before most of the organic matter has been removed.

  1. Chlorine and gallium solar neutrino experiments

    Science.gov (United States)

    Bahcall, J. N.; Cleveland, B. T.; Davis, R., Jr.; Rowley, J. K.

    1985-05-01

    The authors reevaluate the expected capture rates and their uncertainties for the chlorine and gallium solar neutrino experiments using improved laboratory data and new theoretical calculations. They also derive a minimum value for the flux of solar neutrinos that is expected provided only (1) that the sun is currently producing energy by fusing light nuclei at the rate that it is emitting energy in the form of photons from its surface and (2) that nothing happens to solar neutrinos on their way to earth. These results are used - together with Monte Carlo simulations - to determine how much gallium is required for a solar neutrino experiment.

  2. Formation of Emerging Disinfection By-products by Chlorination/Chloramination of Seawater Impacted by Algal Organic Matter

    KAUST Repository

    Nihemaiti, Maolida

    2015-08-31

    The aim of this work was to study the formation of haloacetamides (HAcAms) and other DBPs during chlorination and chloramination of algal organic matter (AlOM). The HAcAms formation potentials of different precursors (amino acids, simulated algal blooms grown in the Red Sea) were evaluated. Experiments with simulated algal blooms were conducted in the presence of bromide ion (synthetic seawater containing 800 μg/L Br−) to assess the formation of brominated analogues of HAcAms in conditions close to the disinfection of real seawater. Chlorination produced more HAcAms than chloramination from real algae (Synecococcus sp.), thus indicating that the nitrogen of HAcAms comes predominantly from DON through the decarboxylation of amino acids rather than from NH2Cl. Dibrominated species of DBPs (i.e., DBAcAm, DBAA and DBAN) were the dominant species formed by both chlorination and chloramination of algal bloom samples. Chloramination of the amino acid asparagine produced an important amount of DCAcAm as compared to chlorination, indicating the existence of a specific reaction pathway.

  3. Modelling of the natural chlorine cycling in a coniferous stand: implications for chlorine-36 behaviour in a contaminated forest environment.

    Science.gov (United States)

    Hoof, Catherine Van den; Thiry, Yves

    2012-05-01

    Considered as one of the most available radionuclide in soil-plant system, ³⁶Cl is of potential concern for long-term management of radioactive wastes, due to its high mobility and its long half-life. To evaluate the risk of dispersion and accumulation of ³⁶Cl in the biosphere as a consequence of a potential contamination, there is a need for an appropriate understanding of the chlorine cycling dynamics in the ecosystems. To date, a small number of studies have investigated the chlorine transfer in the ecosystem including the transformation of chloride to organic chlorine but, to our knowledge, none have modelled this cycle. In this study, a model involving inorganic as well as organic pools in soils has been developed and parameterised to describe the biogeochemical fate of chlorine in a pine forest. The model has been evaluated for stable chlorine by performing a range of sensitivity analyses and by comparing the simulated to the observed values. Finally a range of contamination scenarios, which differ in terms of external supply, exposure time and source, has been simulated to estimate the possible accumulation of ³⁶Cl within the different compartments of the coniferous stand. The sensitivity study supports the relevancy of the model and its compartments, and has highlighted the chlorine transfers affecting the most the residence time of chlorine in the stand. Compared to observations, the model simulates realistic values for the chlorine content within the different forest compartments. For both atmospheric and underground contamination scenarios most of the chlorine can be found in its organic form in the soil. However, in case of an underground source, about two times less chlorine accumulates in the system and proportionally more chlorine leaves the system through drainage than through volatilisation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Bacterial oxidation of low-chlorinated compounds under anoxic conditions

    NARCIS (Netherlands)

    Dijk, J.A.

    2005-01-01

    Chlorinated hydrocarbons belong to the most frequently encountered contaminants in soil and groundwater. Many of them were found to be toxic and recalcitrant, which causes a potential threat to the environment. Therefore, it is of great importance that sites contaminated with chlorinated hydrocarbon

  5. Chlorine Dioxide Induced Multiple Chemical Sensitivity: MMPI Validity Problems.

    Science.gov (United States)

    Tentoni, Stuart C.

    This paper discusses Minnesota Multiphasic Personality Inventory (MMPI) data obtained from individuals exposed to chlorine dioxide in the workplace who developed Multiple Chemical Sensitivity Syndrome. The paper explores current research on chlorine dioxide exposed persons who were misdiagnosed on the basis of MMPI interpretations. Difficulties…

  6. Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinshan; Xue, Jinling; Xu, Bi; Xie, Jiani [Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084 (China); Qiao, Juan, E-mail: qjuan@tsinghua.edu.cn [Department of Chemistry, Tsinghua University, Beijing 100084 (China); Lu, Yun, E-mail: luyun@tsinghua.edu.cn [Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084 (China)

    2016-02-13

    Highlights: • Chlorination is effective to reduce the inflammation inducing capacity of LPS in lung. • LAL-detected endotoxin activity is not correlated to the potency of inflammation induction. • Alkyl chain of LPS was chlorinated in chlorination process. • LPS aggregate size decreases after chlorination. - Abstract: Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies.

  7. 75 FR 23303 - Chlorinated Isocyanurates From China and Spain

    Science.gov (United States)

    2010-05-03

    ... COMMISSION Chlorinated Isocyanurates From China and Spain AGENCY: United States International Trade... isocyanurates from China and Spain. SUMMARY: The Commission hereby gives notice that it has instituted reviews... revocation of the antidumping duty orders on chlorinated isocyanurates from China and Spain would be...

  8. 75 FR 51113 - Chlorinated Isocyanurates From China and Spain

    Science.gov (United States)

    2010-08-18

    ... COMMISSION Chlorinated Isocyanurates From China and Spain AGENCY: United States International Trade... chlorinated isocyanurates from China and Spain. SUMMARY: The Commission hereby gives notice of the scheduling... from China and Spain would be likely to lead to continuation or recurrence of material injury within...

  9. Chlorine Dioxide Induced Multiple Chemical Sensitivity: MMPI Validity Problems.

    Science.gov (United States)

    Tentoni, Stuart C.

    This paper discusses Minnesota Multiphasic Personality Inventory (MMPI) data obtained from individuals exposed to chlorine dioxide in the workplace who developed Multiple Chemical Sensitivity Syndrome. The paper explores current research on chlorine dioxide exposed persons who were misdiagnosed on the basis of MMPI interpretations. Difficulties…

  10. Chlorine-containing natural compounds in higher plants

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1986-01-01

    More than 130 chlorine-containing compounds have been isolated from higher plants and ferns; about half are polyacetylenes, thiophenes and sesquiterpene lactones from the Asteraceae. A chlorinated chlorophyll may be an important part of photosystem 1. High biological activity is found in 4...

  11. Experimental and Theoretical Studies of Atmosphereic Inorganic Chlorine Chemistry

    Science.gov (United States)

    Sander, Stanley P.; Friedl, Randall R.

    1993-01-01

    Over the last five years substantial progress has been made in defining the realm of new chlorine chemistry in the polar stratosphere. Application of existing experimental techniques to potentially important chlorine-containing compounds has yielded quantitative kinetic and spectroscopic data as well as qualitative mechanistic insights into the relevant reactions.

  12. Bacterial oxidation of low-chlorinated compounds under anoxic conditions

    NARCIS (Netherlands)

    Dijk, J.A.

    2005-01-01

    Chlorinated hydrocarbons belong to the most frequently encountered contaminants in soil and groundwater. Many of them were found to be toxic and recalcitrant, which causes a potential threat to the environment. Therefore, it is of great importance that sites contaminated with chlorinated

  13. 78 FR 66767 - Chlorinated Isocyanurates From China and Japan

    Science.gov (United States)

    2013-11-06

    ... COMMISSION Chlorinated Isocyanurates From China and Japan Determinations On the basis of the record \\1... injured by reason of imports from China and Japan of chlorinated isocyanurates, provided for in... than fair value (LTFV) from Japan and subsidized by the Government of China.\\2\\ \\1\\ The record is...

  14. Bacterial oxidation of low-chlorinated compounds under anoxic conditions

    NARCIS (Netherlands)

    Dijk, J.A.

    2005-01-01

    Chlorinated hydrocarbons belong to the most frequently encountered contaminants in soil and groundwater. Many of them were found to be toxic and recalcitrant, which causes a potential threat to the environment. Therefore, it is of great importance that sites contaminated with chlorinated hydrocarbon

  15. Effects of short-chain chlorinated paraffins on soil organisms.

    Science.gov (United States)

    Bezchlebová, Jitka; Cernohlávková, Jitka; Kobeticová, Klára; Lána, Jan; Sochová, Ivana; Hofman, Jakub

    2007-06-01

    Despite the fact that chlorinated paraffins have been produced in relatively large amounts, and high concentrations have been found in sewage sludge applied to soils, there is little information on their concentrations in soils and the effect on soil organisms. The aim of this study was to investigate the toxicity of chlorinated paraffins in soils. The effects of short-chain chlorinated paraffins (64% chlorine content) on invertebrates (Eisenia fetida, Folsomia candida, Enchytraeus albidus, Enchytraeus crypticus, Caenorhabditis elegans) and substrate-induced respiration of indigenous microorganisms were studied. Differences were found in the sensitivity of the tested organisms to short-chain chlorinated paraffins. F. candida was identified as the most sensitive organism with LC(50) and EC(50) values of 5733 and 1230 mg/kg, respectively. Toxicity results were compared with available studies and the predicted no effect concentration (PNEC) of 5.28 mg/kg was estimated for the soil environment, based on our data.

  16. Biodegradability of Chlorinated Anilines in Waters

    Institute of Scientific and Technical Information of China (English)

    CHAO WANG; GUAN-GHUA LU; YAN-JIE ZHOU

    2007-01-01

    Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes,Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2,4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.

  17. Degradation of sulfamethoxazole using ozone and chlorine dioxide - Compound-specific stable isotope analysis, transformation product analysis and mechanistic aspects.

    Science.gov (United States)

    Willach, Sarah; Lutze, Holger V; Eckey, Kevin; Löppenberg, Katja; Lüling, Michelle; Terhalle, Jens; Wolbert, Jens-Benjamin; Jochmann, Maik A; Karst, Uwe; Schmidt, Torsten C

    2017-10-01

    The sulfonamide antibiotic sulfamethoxazole (SMX) is a widely detected micropollutant in surface and groundwaters. Oxidative treatment with e.g. ozone or chlorine dioxide is regularly applied for disinfection purposes at the same time exhibiting a high potential for removal of micropollutants. Especially for nitrogen containing compounds such as SMX, the related reaction mechanisms are largely unknown. In this study, we systematically investigated reaction stoichiometry, product formation and reaction mechanisms in reactions of SMX with ozone and chlorine dioxide. To this end, the neutral and anionic SMX species, which may occur at typical pH-values of water treatment were studied. Two moles of chlorine dioxide and approximately three moles of ozone were consumed per mole SMX degraded. Oxidation of SMX with ozone and chlorine dioxide leads in both cases to six major transformation products (TPs) as revealed by high-resolution mass spectrometry (HRMS). Tentatively formulated TP structures from other studies could partly be confirmed by compound-specific stable isotope analysis (CSIA). However, for one TP, a hydroxylated SMX, it was not possible by HRMS alone to identify whether hydroxylation occurred at the aromatic ring, as suggested in literature before, or at the anilinic nitrogen. By means of CSIA and an analytical standard it was possible to identify sulfamethoxazole hydroxylamine unequivocally as one of the TPs of the reaction of SMX with ozone as well as with chlorine dioxide. H-abstraction and electron transfer at the anilinic nitrogen are suggested as likely initial reactions of ozone and chlorine dioxide, respectively, leading to its formation. Oxidation of anionic SMX with ozone did not show any significant isotopic fractionation whereas the other reactions studied resulted in a significant carbon isotope fractionation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Chlorinated Persistent Organic Pollutants, Obesity, and Type 2 Diabetes

    Science.gov (United States)

    Porta, Miquel; Jacobs, David R.; Vandenberg, Laura N.

    2014-01-01

    Persistent organic pollutants (POPs) are lipophilic compounds that travel with lipids and accumulate mainly in adipose tissue. Recent human evidence links low-dose POPs to an increased risk of type 2 diabetes (T2D). Because humans are contaminated by POP mixtures and POPs possibly have nonmonotonic dose-response relations with T2D, critical methodological issues arise in evaluating human findings. This review summarizes epidemiological results on chlorinated POPs and T2D, and relevant experimental evidence. It also discusses how features of POPs can affect inferences in humans. The evidence as a whole suggests that, rather than a few individual POPs, background exposure to POP mixtures—including organochlorine pesticides and polychlorinated biphenyls—can increase T2D risk in humans. Inconsistent statistical significance for individual POPs may arise due to distributional differences in POP mixtures among populations. Differences in the observed shape of the dose-response curves among human studies may reflect an inverted U-shaped association secondary to mitochondrial dysfunction or endocrine disruption. Finally, we examine the relationship between POPs and obesity. There is evidence in animal studies that low-dose POP mixtures are obesogenic. However, relationships between POPs and obesity in humans have been inconsistent. Adipose tissue plays a dual role of promoting T2D and providing a relatively safe place to store POPs. Large prospective studies with serial measurements of a broad range of POPs, adiposity, and clinically relevant biomarkers are needed to disentangle the interrelationships among POPs, obesity, and the development of T2D. Also needed are laboratory experiments that more closely mimic real-world POP doses, mixtures, and exposure duration in humans. PMID:24483949

  19. Dissection of the mechanism of manganese porphyrin-catalyzed chlorine dioxide generation.

    Science.gov (United States)

    Umile, Thomas P; Wang, Dong; Groves, John T

    2011-10-17

    Chlorine dioxide, an industrially important biocide and bleach, is produced rapidly and efficiently from chlorite ion in the presence of water-soluble, manganese porphyrins and porphyrazines at neutral pH under mild conditions. The electron-deficient manganese(III) tetra-(N,N-dimethyl)imidazolium porphyrin (MnTDMImP), tetra-(N,N-dimethyl)benzimidazolium (MnTDMBImP) porphyrin, and manganese(III) tetra-N-methyl-2,3-pyridinoporphyrazine (MnTM23PyPz) were found to be the most efficient catalysts for this process. The more typical manganese tetra-4-N-methylpyridiumporphyrin (Mn-4-TMPyP) was much less effective. Rates for the best catalysts were in the range of 0.24-32 TO/s with MnTM23PyPz being the fastest. The kinetics of reactions of the various ClO(x) species (e.g., chlorite ion, hypochlorous acid, and chlorine dioxide) with authentic oxomanganese(IV) and dioxomanganese(V)MnTDMImP intermediates were studied by stopped-flow spectroscopy. Rate-limiting oxidation of the manganese(III) catalyst by chlorite ion via oxygen atom transfer is proposed to afford a trans-dioxomanganese(V) intermediate. Both trans-dioxomanganese(V)TDMImP and oxoaqua-manganese(IV)TDMImP oxidize chlorite ion by 1-electron, generating the product chlorine dioxide with bimolecular rate constants of 6.30 × 10(3) M(-1) s(-1) and 3.13 × 10(3) M(-1) s(-1), respectively, at pH 6.8. Chlorine dioxide was able to oxidize manganese(III)TDMImP to oxomanganese(IV) at a similar rate, establishing a redox steady-state equilibrium under turnover conditions. Hypochlorous acid (HOCl) produced during turnover was found to rapidly and reversibly react with manganese(III)TDMImP to give dioxoMn(V)TDMImP and chloride ion. The measured equilibrium constant for this reaction (K(eq) = 2.2 at pH 5.1) afforded a value for the oxoMn(V)/Mn(III) redox couple under catalytic conditions (E' = 1.35 V vs NHE). In subsequent processes, chlorine dioxide reacts with both oxomanganese(V) and oxomanganese(IV)TDMImP to afford chlorate

  20. Synergetic Inactivation of Microorganisms in Drinking Water by Short-term Free Chlorination and Subsequent Monochloramination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli,Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

  1. Chlorine inactivation of Tubifex tubifex in drinking water and the synergistic effect of sequential inactivation with UV irradiation and chlorine.

    Science.gov (United States)

    Nie, Xiao-Bao; Li, Zhi-Hong; Long, Yuan-Nan; He, Pan-Pan; Xu, Chao

    2017-06-01

    The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × timereaction) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, Ea, induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (CODMn) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and CODMn concentrations contributed to the inactivation of T. tubifex.

  2. Effects of chlorine or chlorine dioxide during immersion chilling on recovery of bacteria from broiler carcasses and chiller water

    Science.gov (United States)

    A study was conducted to determine the microbiological impact of immersion chilling broiler carcasses with chlorine or chlorine dioxide. Eviscerated, pre-chill commercial broiler carcasses were cut into left and right halves along the keel bone, and each half was rinsed (HCR) in 100 mL of 0.1% pept...

  3. Change in genotoxicity of wastewater during chlorine dioxide and chlorine disinfections and the influence of ammonia nitrogen

    Institute of Scientific and Technical Information of China (English)

    WANG Lisha; HU Hongying; WANG Chao; Koichi Fujie

    2007-01-01

    The effects of chlorine dioxide and chlorine disinfections on the genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test.The experiment results showed that when chlorine dioxide dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater first decreased rapidly and then tended to be stable,while when the chlorine dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater changed diversely for different samples.It was then found that ammonia nitrogen did not affect the change of genotoxicity during chlorine dioxide disinfection of wastewater,while it greatly affected the change of genotoxicity during chlorine disinfection of wastewater.When the concentration of ammonia nitrogen was low(<10-20mg/L),the genotoxicity of wastewater decreased after chlorine disinfection,and when the concentration of ammonia nitrogen was high(>10-20 mg/L),the genotoxicity of wastewater increased after chlorine disinfection.

  4. LC-ESI-MS/MS identification of polar lipids of two thermophilic Anoxybacillus bacteria containing a unique lipid pattern.

    Science.gov (United States)

    Rezanka, Tomáš; Kambourova, Margarita; Derekova, Anna; Kolouchová, Irena; Sigler, Karel

    2012-07-01

    Phospholipids and glycolipids from two recently described species belonging to the thermophilic genus Anoxybacillus were analyzed by liquid chromatography-electrospray tandem mass spectrometry (LC/ESI-MS/MS). Analysis of total lipids from the facultatively anaerobic A. bogrovensis on a HILIC (Hydrophilic Interaction LIquid Chromatography) column succeeded in separating diacyl- and plasmalogen phospholipids. The LC/ESI-MS/MS analysis of the strict aerobe A. rupiensis revealed the presence of different unique polar lipids, predominantly alanyl-, lysyl-, and glucosyl-phosphatidylglycerols and cardiolipins. Each of the classes of polar lipids was then analyzed by means of the ESI-MS/MS and more than 140 molecular species of six lipid classes from A. bogrovensis and nearly 200 molecular species of nine classes of polar lipids from A. rupiensis were identified. Five classes of unidentified polar lipids were detected in both strains. Plasmalogens were thus determined for the first time in a facultatively anaerobic bacterium, i.e. A. bogrovensis.

  5. LipidPioneer : A Comprehensive User-Generated Exact Mass Template for Lipidomics

    Science.gov (United States)

    Ulmer, Candice Z.; Koelmel, Jeremy P.; Ragland, Jared M.; Garrett, Timothy J.; Bowden, John A.

    2017-03-01

    Lipidomics, the comprehensive measurement of lipid species in a biological system, has promising potential in biomarker discovery and disease etiology elucidation. Advances in chromatographic separation, mass spectrometric techniques, and novel substrate applications continue to expand the number of lipid species observed. The total number and type of lipid species detected in a given sample are generally indicative of the sample matrix examined (e.g., serum, plasma, cells, bacteria, tissue, etc.). Current exact mass lipid libraries are static and represent the most commonly analyzed matrices. It is common practice for users to manually curate their own lists of lipid species and adduct masses; however, this process is time-consuming. LipidPioneer, an interactive template, can be used to generate exact masses and molecular formulas of lipid species that may be encountered in the mass spectrometric analysis of lipid profiles. Over 60 lipid classes are present in the LipidPioneer template and include several unique lipid species, such as ether-linked lipids and lipid oxidation products. In the template, users can add any fatty acyl constituents without limitation in the number of carbons or degrees of unsaturation. LipidPioneer accepts naming using the lipid class level (sum composition) and the LIPID MAPS notation for fatty acyl structure level. In addition to lipid identification, user-generated lipid m/z values can be used to develop inclusion lists for targeted fragmentation experiments. Resulting lipid names and m/z values can be imported into software such as MZmine or Compound Discoverer to automate exact mass searching and isotopic pattern matching across experimental data.

  6. LipidPioneer : A Comprehensive User-Generated Exact Mass Template for Lipidomics

    Science.gov (United States)

    Ulmer, Candice Z.; Koelmel, Jeremy P.; Ragland, Jared M.; Garrett, Timothy J.; Bowden, John A.

    2017-01-01

    Lipidomics, the comprehensive measurement of lipid species in a biological system, has promising potential in biomarker discovery and disease etiology elucidation. Advances in chromatographic separation, mass spectrometric techniques, and novel substrate applications continue to expand the number of lipid species observed. The total number and type of lipid species detected in a given sample are generally indicative of the sample matrix examined (e.g., serum, plasma, cells, bacteria, tissue, etc.). Current exact mass lipid libraries are static and represent the most commonly analyzed matrices. It is common practice for users to manually curate their own lists of lipid species and adduct masses; however, this process is time-consuming. LipidPioneer, an interactive template, can be used to generate exact masses and molecular formulas of lipid species that may be encountered in the mass spectrometric analysis of lipid profiles. Over 60 lipid classes are present in the LipidPioneer template and include several unique lipid species, such as ether-linked lipids and lipid oxidation products. In the template, users can add any fatty acyl constituents without limitation in the number of carbons or degrees of unsaturation. LipidPioneer accepts naming using the lipid class level (sum composition) and the LIPID MAPS notation for fatty acyl structure level. In addition to lipid identification, user-generated lipid m/z values can be used to develop inclusion lists for targeted fragmentation experiments. Resulting lipid names and m/z values can be imported into software such as MZmine or Compound Discoverer to automate exact mass searching and isotopic pattern matching across experimental data.

  7. Sensitivity of an atmospheric photochemistry model to chlorine perturbations including consideration of uncertainty propagation

    Science.gov (United States)

    Stolarski, R. S.; Douglass, A. R.

    1986-01-01

    Models of stratospheric photochemistry are generally tested by comparing their predictions for the composition of the present atmosphere with measurements of species concentrations. These models are then used to make predictions of the atmospheric sensitivity to perturbations. Here the problem of the sensitivity of such a model to chlorine perturbations ranging from the present influx of chlorine-containing compounds to several times that influx is addressed. The effects of uncertainties in input parameters, including reaction rate coefficients, cross sections, solar fluxes, and boundary conditions, are evaluated using a Monte Carlo method in which the values of the input parameters are randomly selected. The results are probability distributions for present atmosheric concentrations and for calculated perturbations due to chlorine from fluorocarbons. For more than 300 Monte Carlo runs the calculated ozone perturbation for continued emission of fluorocarbons at today's rates had a mean value of -6.2 percent, with a 1-sigma width of 5.5 percent. Using the same runs but only allowing the cases in which the calculated present atmosphere values of NO, NO2, and ClO at 25 km altitude fell within the range of measurements yielded a mean ozone depletion of -3 percent, with a 1-sigma deviation of 2.2 percent. The model showed a nonlinear behavior as a function of added fluorocarbons. The mean of the Monte Carlo runs was less nonlinear than the model run using mean value of the input parameters.

  8. Formation of assimilable organic carbon during oxidation of natural waters with ozone, chlorine dioxide, chlorine, permanganate, and ferrate.

    Science.gov (United States)

    Ramseier, Maaike K; Peter, Andreas; Traber, Jacqueline; von Gunten, Urs

    2011-02-01

    Five oxidants, ozone, chlorine dioxide, chlorine, permanganate, and ferrate were studied with regard to the formation of assimilable organic carbon (AOC) and oxalate in absence and presence of cyanobacteria in lake water matrices. Ozone and ferrate formed significant amounts of AOC, i.e. more than 100 μg/L AOC were formed with 4.6 mg/L ozone and ferrate in water with 3.8 mg/L dissolved organic carbon. In the same water samples chlorine dioxide, chlorine, and permanganate produced no or only limited AOC. When cyanobacterial cells (Aphanizomenon gracile) were added to the water, an AOC increase was detected with ozone, permanganate, and ferrate, probably due to cell lysis. This was confirmed by the increase of extracellular geosmin, a substance found in the selected cyanobacterial cells. AOC formation by chlorine and chlorine dioxide was not affected by the presence of the cells. The formation of oxalate upon oxidation was found to be a linear function of the oxidant consumption for all five oxidants. The following molar yields were measured in three different water matrices based on oxidant consumed: 2.4-4.4% for ozone, 1.0-2.8% for chlorine dioxide and chlorine, 1.1-1.2% for ferrate, and 11-16% for permanganate. Furthermore, oxalate was formed in similar concentrations as trihalomethanes during chlorination (yield ∼ 1% based on chlorine consumed). Oxalate formation kinetics and stoichiometry did not correspond to the AOC formation. Therefore, oxalate cannot be used as a surrogate for AOC formation during oxidative water treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Chlorosome-Inspired Synthesis of Templated Metallochlorin-Lipid Nanoassemblies for Biomedical Applications.

    Science.gov (United States)

    Ng, Kenneth K; Takada, Misa; Harmatys, Kara; Chen, Juan; Zheng, Gang

    2016-04-26

    Chlorosomes are vesicular light-harvesting organelles found in photosynthetic green sulfur bacteria. These organisms thrive in low photon flux environments due to the most efficient light-to-chemical energy conversion, promoted by a protein-less assembly of chlorin pigments. These assemblies possess collective absorption properties and can be adapted for contrast-enhanced bioimaging applications, where maximized light absorption in the near-infrared optical window is desired. Here, we report a strategy for tuning light absorption toward the near-infrared region by engineering a chlorosome-inspired assembly of synthetic metallochlorins in a biocompatible lipid scaffold. In a series of synthesized chlorin analogues, we discovered that lipid conjugation, central coordination of a zinc metal into the chlorin ring, and a 3(1)-methoxy substitution were critical for the formation of dye assemblies in lipid nanovesicles. The substitutions result in a specific optical shift, characterized by a bathochromically shifted (72 nm) Qy absorption band, along with an increase in absorbance and circular dichroism as the ratio of dye-conjugated lipid was increased. These alterations in optical spectra are indicative of the formation of delocalized excitons states across each molecular assembly. This strategy of tuning absorption by mimicking the structures found in photosynthetic organisms may spur new opportunities in the development of biophotonic contrast agents for medical applications.

  10. The use of chlorine dioxide for zebra mussel control - A perspective of treatment histories

    Energy Technology Data Exchange (ETDEWEB)

    Smolik, N.; Rusznak, L.; Anderson, J.; Hale, L. [Ashland Chemical Coman, Drew Division, Booton, NJ (United States)

    1995-06-01

    It is of utmost importance to provide updated performance results of various chemical treatments presently being utilized for zebra mussel control. Zebra mussels have a distinctive ability to endure environmental changes by reproducing effectively and attaching to various hard surfaces. These traits are cause for concern and have resulted in some operating difficulties for industries bordering infested waterways. Various methods are being employed by industries to deal with the problems associated with these species. One of the options is control via chemical treatment. Prior field test studies showed that chlorine dioxide was determined to be an effective molluscicidal agent for adult zebra mussel eradication. Continuous feed of chlorine dioxide at treatment levels ranging from 0.25 - 5.0 ppm above the oxidant demand provided 100% adult zebra mussel mortality which required between 2.9 - 8.8 days of treatment. Previous studies also showed that water temperature was an essential parameter in determining the time required to achieve 100% mortality of adult zebra mussels. Further field applications were undertaken at three electric utility sites located in the midwest. These facilities were concerned with the potential for zebra mussels to reduce efficiency and availability by blocking water flow or plugging equipment. Treatment applications at these facilities consisted of a continuous feed of chlorine dioxide ranging from 0.15 - 0.5 ppm above the oxidant demand. Significant mortality was achieved in monitored mussels tested at each utility in a period ranging from two to four days. This time period was directly related to a number of parameters, with the predominant one being water temperature. Data from these field applications is presented in this paper and confirms that chlorine dioxide is an effective molluscicide for adult zebra mussel control.

  11. A chemical thermodynamics review applied to V{sub 2}O{sub 5} chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Brocchi, E.A., E-mail: ebrocchi@puc-rio.br [Materials Engineering Department (PUC-Rio), Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro (Brazil); Navarro, R.C.S., E-mail: rogerioncs@gmail.com [Materials Engineering Department (PUC-Rio), Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro (Brazil); Moura, F.J. [Materials Engineering Department (PUC-Rio), Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro (Brazil)

    2013-05-10

    Highlights: ► A chemical thermodynamics review of V{sub 2}O{sub 5} chlorination based on available thermodynamics data and software. ► Discuss the importance of ΔG° × T plots to study the viability of chlorination reactions. ► Reinforce the relationship between ΔG° × T and predominance diagrams, when plotted with thermodynamic consistency. ► Application of different computational methods with diverse complexity for studying the nature of equilibrium states. ► Speciation calculations to study the effect of temperature, partial pressure of O{sub 2} and Cl{sub 2} over chemical equilibrium. - Abstract: This work is mainly related to the thermodynamic study of the V{sub 2}O{sub 5} carbon-chlorination. In this context, three different approaches of diverse complexity level were employed. First, the formation of individual vanadium chlorides and oxychlorides were considered on the basis of the well known ΔG° × T diagrams. It is suggested that these simple constructions can help in understanding the formation sequence of vanadium chlorinated species. Moreover, the relative stability of the most stable vanadium chloride (VCl{sub 4}) and oxychloride (VOCl{sub 3}) was addressed based on available thermodynamics data. Finally, a gas phase speciation calculation was performed in order to obtain, simultaneously, the concentration of all possible vanadium chlorides and oxychlorides as a function of temperature, Cl{sub 2} and O{sub 2} partial pressures. It is demonstrated that, although diverse in the complexity level, the three methods considered have a strong relation with each other, and converge to a better insight into the nature of the chemical equilibrium states achievable for the reaction system under study. The same approach can be applied to any other reaction system of technological importance.

  12. Doxorubicin Lipid Complex Injection

    Science.gov (United States)

    Doxorubicin lipid complex is used to treat ovarian cancer that has not improved or that has worsened after treatment with other medications. Doxorubicin lipid complex is also used to treat Kaposi's ...

  13. Irinotecan Lipid Complex Injection

    Science.gov (United States)

    Irinotecan lipid complex is used in combination with other medications to treat pancreatic cancer that has spread to other ... worsened after treatment with other chemotherapy medications. Irinotecan lipid complex is in a class of antineoplastic medications ...

  14. Daunorubicin Lipid Complex Injection

    Science.gov (United States)

    Daunorubicin lipid complex is used to treat advanced Kaposi's sarcoma (a type of cancer that causes abnormal tissue to ... body) related to acquired immunodeficiency syndrome (AIDS). Daunorubicin lipid complex is in a class of medications called ...

  15. Vincristine Lipid Complex Injection

    Science.gov (United States)

    Vincristine lipid complex is used to treat a certain type of acute lymphoblastic leukemia (ALL; a type of cancer ... least two different treatments with other medications. Vincristine lipid complex is in a class of medications called ...

  16. Parenteral Nutrition and Lipids.

    Science.gov (United States)

    Raman, Maitreyi; Almutairdi, Abdulelah; Mulesa, Leanne; Alberda, Cathy; Beattie, Colleen; Gramlich, Leah

    2017-04-14

    Lipids have multiple physiological roles that are biologically vital. Soybean oil lipid emulsions have been the mainstay of parenteral nutrition lipid formulations for decades in North America. Utilizing intravenous lipid emulsions in parenteral nutrition has minimized the dependence on dextrose as a major source of nonprotein calories and prevents the clinical consequences of essential fatty acid deficiency. Emerging literature has indicated that there are benefits to utilizing alternative lipids such as olive/soy-based formulations, and combination lipids such as soy/MCT/olive/fish oil, compared with soybean based lipids, as they have less inflammatory properties, are immune modulating, have higher antioxidant content, decrease risk of cholestasis, and improve clinical outcomes in certain subgroups of patients. The objective of this article is to review the history of IVLE, their composition, the different generations of widely available IVLE, the variables to consider when selecting lipids, and the complications of IVLE and how to minimize them.

  17. Extraction of lipids from microalgae using CO2-expanded methanol and liquid CO2.

    Science.gov (United States)

    Paudel, Ashok; Jessop, Michael J; Stubbins, Spencer H; Champagne, Pascale; Jessop, Philip G

    2015-05-01

    The use of CO2-expanded methanol (cxMeOH) and liquid carbon dioxide (lCO2) is proposed to extract lipids from Botryococcus braunii. When compressed CO2 dissolves in methanol, the solvent expands in volume, decreases in polarity and so increases in its selectivity for biodiesel desirable lipids. Solid phase extraction of the algal extract showed that the cxMeOH extracted 21 mg of biodiesel desirable lipids per mL of organic solvent compared to 3mg/mL using either neat methanol or chloroform/methanol mixture. The non-polar lCO2 showed a high affinity for non-polar lipids. Using lCO2, it is possible to extract up to 10% neutral lipids relative to the mass of dry algae. Unlike extractions using conventional solvents, these new methods require little to no volatile, flammable, or chlorinated organic solvents. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Pourbaix diagrams for the system copper-chlorine at 5-100 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Beverskog, B. [Studsvik Material AB, Nykoeping (Sweden); Puigdomenech, I. [Studsvik Eco and Safety AB, Nykoeping (Sweden)

    1998-04-01

    Pourbaix diagrams for the copper-chlorine system in the temperature interval 5-100 deg C have been revised. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of each dissolved element, 10{sup -4} and 10{sup -6} molal for copper and 0.2 and 1.5 molal for chlorine have been used in the calculations. Chloride is the predominating chlorine species in aqueous solutions. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. CuCl{sub 2} {center_dot} 3Cu(OH){sub 2} is the only copper-chloride solid phase that forms at the concentrations of chlorine studied. However, its stability area decreases with increasing temperature. The ion CuCl{sub 2}{sup -} predominates at all temperatures at [Cl(aq)]{sub tot}=0.2 molal and this reduces the immunity and passivity areas. A corrosion region exists between the immunity and passivity regions at 100 deg C at [Cu(aq)]{sub tot}=10{sup -6} and [Cl(aq)]{sub tot}=0.2 molal. At the chlorine concentration of 1.5 molal the corrosion region exists in the whole temperature range investigated. The ion CuCl{sub 3}{sup 2-} predominates at 5-25 and 100 deg C, while CuCl{sub 2}{sup -} predominates at 50-80 deg C at [Cl(aq)]{sub tot=}1-5 molal. A copper concentration of 10{sup -4} molal reduces the corrosion areas due to expansion of the immunity and passivity areas. However, a corrosion region still exists between the immunity and passivity regions at all investigated temperatures at pH{sub {Tau}}<9.5 and 1.5 molal chloride concentration. According to our calculations the copper canisters in the deep nuclear waste repository should not corrode at the copper concentration of 10{sup -6} molal and the chloride concentration of 0.2 molal. However, at 80-100 deg C the equilibrium potentials postulated for the Swedish nuclear repository are dangerously close to a corrosion situation. According to

  19. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pipon, Y. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France) and Universite Claude Bernard Lyon-1, Institut Universitaire de Technologie (IUT A), 94, boulevard Niels Bohr, 69622 Villeurbanne cedex (France)]. E-mail: pipon@ipnl.in2p3.fr; Bererd, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Universite Claude Bernard Lyon-1, Institut Universitaire de Technologie (IUT A), 94, boulevard Niels Bohr, 69622 Villeurbanne cedex (France); Moncoffre, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Peaucelle, C. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Toulhoat, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Commissariat a l' Energie Atomique (CEA), DEN/Saclay, 91191 Gif sur Yvette cedex (France); Jaffrezic, H. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Raimbault, L. [Ecole des Mines de Paris, Centre de Geosciences, 35 rue Saint Honore, F-77305 Fontainebleau cedex (France); Sainsot, P. [Institut National des Sciences Appliquees de Lyon (INSA), UMR 5514, F-69621 Villeurbanne cedex (France); Carlot, G. [Commissariat a l' Energie Atomique (CEA), Centre de Cadarache, DEN/DEC/SESC/LLCC, 13108 Saint-Paul lez Durance (France)

    2007-04-15

    The radiation enhanced diffusion of chlorine in UO{sub 2} during heavy ion irradiation is studied. In order to simulate the behaviour of {sup 36}Cl, present as an impurity in UO{sub 2}, {sup 37}Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV {sup 127}I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 x 10{sup -14} cm{sup 2} s{sup -1}, reflect the high mobility of chlorine in UO{sub 2} during irradiation with fission products.

  20. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    Science.gov (United States)

    Pipon, Y.; Bérerd, N.; Moncoffre, N.; Peaucelle, C.; Toulhoat, N.; Jaffrézic, H.; Raimbault, L.; Sainsot, P.; Carlot, G.

    2007-04-01

    The radiation enhanced diffusion of chlorine in UO2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36Cl, present as an impurity in UO2, 37Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 127I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 × 10-14 cm2 s-1, reflect the high mobility of chlorine in UO2 during irradiation with fission products.

  1. Does chlorination of seawater reverse osmosis membranes control biofouling?

    Science.gov (United States)

    Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

    2015-07-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  2. Efficacy of chlorine dioxide tablets on inactivation of cryptosporidium oocysts.

    Science.gov (United States)

    Murphy, Jennifer L; Haas, Charles N; Arrowood, Michael J; Hlavsa, Michele C; Beach, Michael J; Hill, Vincent R

    2014-05-20

    The ability of chlorine dioxide (ClO2) to achieve 2-log inactivation of Cryptosporidium in drinking water has been documented. No studies have specifically addressed the effects of ClO2 on C. parvum oocyst infectivity in chlorinated recreational water venues (e.g., pools). The aim of this research was to determine the efficacy of ClO2 as an alternative to existing hyperchlorination protocols that are used to achieve a 3-log inactivation of Cryptosporidium in such venues. To obtain a 3-log inactivation of C. parvum Iowa oocysts, contact times of 105 and 128 min for a solution containing 5 mg/L ClO2 with and without the addition of 2.6 mg/L free chlorine, respectively, were required. Contact times of 294 and 857 min for a solution containing 1.4 mg/L ClO2 with and without the addition of 3.6 mg/L free chlorine, respectively, were required. The hyperchlorination control (21 mg/L free chlorine only) required 455 min for a 3-log inactivation. Use of a solution containing 5 mg/L ClO2 and solutions containing 5 or 1.4 mg/L ClO2 with the addition of free chlorine appears to be a promising alternative to hyperchlorination for inactivating Cryptosporidium in chlorinated recreational water venues, but further studies are required to evaluate safety constraints on use.

  3. Removal effect on Mesocyclops leukarti and mutagenicity with chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    ZUO Jin-long; CUI Fu-yi; QU Bo; ZHU Gui-bing

    2006-01-01

    Mesocyclops leukarti of zooplankton propagates excessively in eutrophic water body and it cannot be effectively inactivated by the conventional drinking water treatment process. In order to tackle this problem, a study of removal effect on Mesocyclops leukarti with chlorine dioxide in a waterworks was performed. The results showed that Mesocyclops leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation combined with the conventional drinking water treatment process.Higher oxidizability and molecular state of chlorine dioxide in water is the key to the inactivation of Mesocyclops leukarti. The chlorite, disinfection by-products (DBPs) of chlorine dioxide, was stable at 0.45 mg/L, which is lower than that critical value of the USEPA. GC-MS examination showed that the quantity of organic substance in the water treated by chlorine dioxide obviously decreased. Ames test further revealed that the mutagenicity was reduced by chlorine dioxide with respect to prechlorine. The propagation ofMesocyclops leukarti can be inactivated effectively and safely by chlorine dioxide pre-oxidation.

  4. Does Chlorination of Seawater Reverse Osmosis Membranes Control Biofouling?

    KAUST Repository

    Khan, Muhammad Tariq

    2015-04-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full–scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  5. Simulating stable carbon and chlorine isotope ratios in dissolved chlorinated groundwater pollutants with BIOCHLOR-ISO

    Science.gov (United States)

    Höhener, Patrick

    2016-12-01

    BIOCHLOR is a well-known simple tool for evaluating the transport of dissolved chlorinated solvents in groundwater, ideal for rapid screening and teaching. This work extends the BIOCHLOR model for the calculation of stable isotope ratios of carbon and chlorine isotopes in chloroethenes. An exact solution for the three-dimensional reactive transport of a chain of degrading compounds including sorption is provided in a spreadsheet and applied for modeling the transport of individual isotopes 12C, 13C, 35Cl, 37Cl from a constant source. The model can consider secondary isotope effects that can occur in the breaking of Csbnd Cl bonds. The model is correctly reproducing results for δ13C and δ37Cl modeled by a previously published 1-D numerical model without secondary isotope effects, and is also reproducing results from a microcosm experiment with secondary chlorine isotope effects. Two applications of the model using field data from literature are further given and discussed. The new BIOCHLOR-ISO model is distributed as a spreadsheet (MS EXCEL) along with this publication.

  6. Safety of water treatment by chlorine dioxide oxidation of aromatic hydrocarbons commonly found in water

    Energy Technology Data Exchange (ETDEWEB)

    Taymaz, K.; Williams, D.T.; Benoit, F.M.

    1979-01-01

    The safety of water treatment by chlorine dioxide oxidation of aromatic hydrocarbons commonly found in water and industrial wastewaters in the US was studied by observing the reactions of naphthalene and methylnaphthalenes in essentially chlorine-free, aqueous chlorine dioxide solutions. Naphthalene and methylnaphthalenes yielded chlorinated derivatives and oxidation products. Further research is recommended.

  7. Characterization of Chlorinated Ethene Degradation in a Vertical Flow Constructed Wetland

    Science.gov (United States)

    2007-03-01

    pathway for chlorinated volatiles in phytoremediation applications. Although transpiration of chlorinated solvents has been confirmed in studies ... case study publications and conference presentations providing support for the use of constructed wetlands for the treatment of chlorinated solvent...groundwater. This study characterized and evaluated the concentration of chlorinated ethenes within a vertical flow constructed wetland, fed with PCE

  8. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems.

  9. Nanoparticle-lipid bilayer interactions studied with lipid bilayer arrays

    Science.gov (United States)

    Lu, Bin; Smith, Tyler; Schmidt, Jacob J.

    2015-04-01

    The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which can provide insight into the nature of the particle-membrane interaction through variation of membrane and solution properties not possible with cell-based assays. However, the scope of these studies can be limited because of the low throughput characteristic of lipid bilayer platforms. We have recently described an easy to use, parallel lipid bilayer platform which we have used to electrically investigate the activity of 60 nm diameter amine and carboxyl modified polystyrene nanoparticles (NH2-NP and COOH-NP) with over 1000 lipid bilayers while varying lipid composition, bilayer charge, ionic strength, pH, voltage, serum, particle concentration, and particle charge. Our results confirm recent studies finding activity of NH2-NP but not COOH-NP. Detailed analysis shows that NH2-NP formed pores 0.3-2.3 nm in radius, dependent on bilayer and solution composition. These interactions appear to be electrostatic, as they are regulated by NH2-NP surface charge, solution ionic strength, and bilayer charge. The ability to rapidly measure a large number of nanoparticle and membrane parameters indicates strong potential of this bilayer array platform for additional nanoparticle bilayer studies.The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which

  10. Aqueous reactions of chlorine dioxide with hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Rav-Acha, C.; Choshen, E.

    1987-11-01

    In contrast to mechanisms proposed earlier in the literature, according to which chlorine dioxide (ClO/sub 2/) reacts with various hydrocarbons in aqueous media by abstracting allylic or benzylic hydrogens, it is shown that ClO/sub 2/ reacts with olefins through initial electron transfer. Hydrocarbons that can undergo facile oxidation, such as polycyclic aromatic hydrocarbons (PAH) and some olefins, react with ClO/sub 2/ quite rapidly, while saturated aliphatic hydrocarbons, some aromatic hydrocarbons, and olefins substituted with electron-withdrawing groups remain unreactive. This was substantiated by comparing the reactivities toward ClO/sub 2/ of a variety of hydrocarbons, including aliphatic and aromatic hydrocarbons, saturated and unsaturated acids, PAH, or cyclic and acyclic olefins. The results were supported by a detailed kinetic and product study of the reaction between ClO/sub 2/ and some model compounds.

  11. Effects of continuous chlorination on entrained estuarine plankton

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, S.J.; Foulk, H.R.

    1980-01-01

    Technical report: The effects of continuous chlorination in running sea water on entrained plankton were examined. The concentration of ATP was used as an indicator of biomass because: it is present in all living cells; the concentration is proportional to the living biomass; and dead cells lose ATP rapidly. Effects were measured by bioluminescence; luciferin-luciferase reagents from firefly lanterns were used to analyze ATP concentration. Results indicate that ATP measurement is an accurate, effective means of evaluating damage done to planktonic organisms by continuous chlorination. Further studies of the effects of low-concentration, continuous chlorination are recommended. (13 references, 1 table)

  12. Release of Chlorine and Sulfur during Biomass Torrefaction and Pyrolysis

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Flensborg, Julie Pauline; Shoulaifar, Tooran Khazraie

    2014-01-01

    The release of chlorine (Cl) and sulfur (S) during biomass torrefaction and pyrolysis has been investigated via experiments in two laboratory-scale reactors: a rotating reactor and a fixed bed reactor. Six biomasses with different chemical compositions covering a wide range of ash content and ash...... reporting that biomasses with a lower chlorine content release a higher fraction of chlorine during the pyrolysis process. A significant sulfur release (about 60%) was observed from the six biomasses investigated at 350 degrees C. The initial sulfur content in the biomass did not influence the fraction...

  13. Chlorine Dioxide Gas Treatment of Cantaloupe and Residue Analysis

    OpenAIRE

    Kaur, Simran

    2013-01-01

    Chlorine dioxide is a selective oxidant and powerful antimicrobial agent. Previous work has shown that treatment of cantaloupe with chlorine dioxide gas at 5 mg/L for 10 minutes results in a 4.6 and 4.3 log reduction of E. coli O157:H7 and L. monocytogenes respectively. A significant reduction (p Current analytical methods for chlorine dioxide and chloroxyanions are only applicable to aqueous samples. Some of these methods have been used to determine surface residues in treated products by...

  14. A comparison of six different ballast water treatment systems based on UV radiation, electrochlorination and chlorine dioxide.

    Science.gov (United States)

    Stehouwer, Peter Paul; Buma, Anita; Peperzak, Louis

    2015-01-01

    The spread of aquatic invasive species through ballast water is a major ecological and economical threat. Because of this, the International Maritime Organization (IMO) set limits to the concentrations of organisms allowed in ballast water. To meet these limits, ballast water treatment systems (BWTSs) were developed. The main techniques used for ballast water treatment are ultraviolet (UV) radiation and electrochlorination (EC). In this study, phytoplankton regrowth after treatment was followed for six BWTSs. Natural plankton communities were treated and incubated for 20 days. Growth, photosystem II efficiency and species composition were followed. The three UV systems all showed similar patterns of decrease in phytoplankton concentrations followed by regrowth. The two EC and the chlorine dioxide systems showed comparable results. However, UV- and chlorine-based treatment systems showed significantly different responses. Overall, all BWTSs reduced phytoplankton concentrations to below the IMO limits, which represents a reduced risk of aquatic invasions through ballast water.

  15. Atmospheric reactivity of alcohols, thiols and fluoroalcohols with chlorine atoms

    Science.gov (United States)

    Garzon Ruiz, Andres

    Alcohols, thiols and fluoroalcohols are volatile organic compounds (VOCs) which are emitted to the atmosphere from both natural (vegetation, oceans, volcanoes, etc.) and anthropogenic sources (fuels, solvents, wastewater, incinerators, refrigerants, etc.). These pollutants can be eliminated from the troposphere by deposition on the terrestrial surface, direct photolysis or reaction with different tropospheric oxidants. Reactions of VOCs with tropospheric oxidants are involved in the well-known atmospheric phenomenon of photochemical smog or the production of tropospheric ozone. The oxidation of these VOCs in the troposphere is mainly initiated by reaction with OH radicals during the daytime and with NO radicals at night. However, in recent years, the oxidation by chlorine atoms (Cl) has gained great importance in the study of atmospheric reactions because they may exert some influence in the boundary layer, particularly in marine and coastal environments. In general, Cl atoms are much more reactive species than OH and NO; radicals and therefore low concentrations of Cl may compete with OH and NO3 in hydrocarbon oxidation processes. The main source of tropospheric Cl atoms is believed to be the photolysis of chlorine-containing molecules generated by heterogeneous reactions of sea salt aerosols. It has also been proposed that Cl atoms, produced in the photolysis of Cl2 emitted from industrial processes, may enhance hydrocarbon oxidation rates and ozone production in urban environments. In this work, a kinetic, theoretical and mechanistic study of the reaction of several alcohols, thiols, and fluoroalcohols with Cl atoms has been carried out. Pulsed laser photolysis-fluorescence resonance (PLP-RF) technique was used for the kinetic study as a function of temperature and pressure. An environmental chamber-Fourier transform infrared (FTIR) system was also employed in the kinetic studies. Tropospheric lifetimes of these pollutants were estimated using obtained kinetic

  16. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of chlorinated pesticides in aquatic tissue by capillary-column gas chromatography with electron-capture detection

    Science.gov (United States)

    Leiker, Thomas J.; Madsen, J.E.; Deacon, J.R.; Foreman, W.T.

    1995-01-01

    A method for the determination of chlorinated organic compounds in aquatic tissue by dual capillary-column gas chromatography with electron-capture detection is described. Whole-body-fish or corbicula tissue is homogenized, Soxhlet extracted, lipid removed by gel permeation chromatography, and fractionated using alumina/silica adsorption chromatography. The extracts are analyzed by dissimilar capillary-column gas chromatography with electron-capture detection. The method reporting limits are 5 micrograms per kilogram (μg/kg) for chlorinated compounds, 50 μg/kg for polychlorinated biphenyls, and 200 μg/kg for toxaphene.

  17. Chlorine-36 and chlorine concentrations within several compartments of a deciduous forest ecosystem in Meuse/Haute-Marne (France)

    Science.gov (United States)

    Pupier, Julie; Benedetti, Lucilla; Bourles, Didier; Leclerc, Elisabeth; Thiry, Yves

    2013-04-01

    Chlorine-36 is a cosmogenic nuclide mainly produced in the atmosphere by interactions between energetic particles originating from the cosmic radiations and 40Ar. Because of its long half-life (T1-2 = 3.01 105 yr) and its high mobility, chlorine-36 is a critical radionuclide concerning radioactive waste repository sites. Moreover, it has been shown that inorganic chlorine could be enriched along the trophic chain due to its high solubility and bioavailability (Ashworth and Shaw, 2006). Additionally, many studies during the last decades have established that due to chlorination process, organic chlorine may account for a large proportion of the total soil chlorine pool (more than 80 % in surface soils of temperate ecosystems. Redon et al., 2012). The aim of this study is thus to measure chlorine-36 in all the compartments of the biogeochemical cycle, to better understand its recycling in the biosphere. The study site is the experimental beech forest site of the Andra long-term monitoring and testing system (OPE*). It is located at Montiers-sur-Saulx, North-East of France and is associated to the future radioactive waste repository site of Bure. Since March 2012, rainwater above (rainfall collected from a 45 m high tower built on purpose) and below (throughfall and stemflow) the canopy, has been collected monthly, as well as soil solutions (gravitational and bound waters) at four depths (0, 10, 30, 60 cm deep). Chlorine-36 and chlorine have been measured in the rainfall samples between March and July 2012 and in water solutions collected from all compartments of the biosphere using isotope dilution mass spectrometry at the french AMS national facility ASTER located at CEREGE. The results yielded from the rainfall samples allow to study the temporal fluctuations of chlorine-36 in the atmosphere, which represents the main inflow of chlorine-36 in its biogeochemical cycle. The first results indicate a flow increase during the late spring-early summer. Santos et al

  18. Selective determination of chlorine dioxide using gas diffusion flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hollowell, D.A.; Pacey, G.E.; Gordon, G.

    1985-12-01

    An automated absorbance technique for the determination of aqueous chlorine dioxide has been developed by utilizing gas diffusion flow injection analysis. A gas diffusion membrane is used to separate the donor (sampling) stream from the acceptor (detecting) stream. The absorbance of chlorine dioxide is monitored at 359 nm. The first method uses distilled water as the acceptor stream and gives a detection limit of 0.25 mg/L chlorine dioxide. This system is over 550 times more selective for chlorine dioxide than chlorine. To further minimize chlorine interference, oxalic acid is used in the acceptor stream. The detection limit for this system is 0.45 mg/L chlorine dioxide. This second system is over 5400 times more selective for chlorine dioxide than chlorine. Both methods show excellent selectivity for chlorine dioxide over iron and manganese compounds, as well as other oxychlorinated compounds such as chlorite and perchlorate ions. 18 references, 7 figures, 3 tables.

  19. RESEARCH ON MATHEMATICAL SIMULATION OF RESIDUAL CHLORINE DECAY AND OPTIMIZATION OF CHLORINATION ALLOCATION OF URBAN WATER DISTRIBUTION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    TIAN Yi-mei; CHI Hai-yan; LI Hong; SHAN Jin-lin; ZHAI Chun-nian

    2005-01-01

    The concentration of Residual Chlorine (RC) frequently violates the standard in situations of urban water distribution system with large water supply area and long time of distribution.If chlorine dosage increases within water treatment plant, although RC in distribution system could meet water quality standard, Disinfection By-Products (DBPs) such as hydrocarbon halide rises.In the paper, a mathematical model of chlorine allocation optimization was presented based on reaction kinetics mechanism and optimization theory to solve the problem.The model includes the objective function of minimizing annual operation cost and constraints of RC standard and rational chlorination station distribution, and solving by 0-1 Integer Programming (IP).The model had been applied to a real water distribution system.The simulation results of the model showed that adding chlorine in water distribution system remarkably improved water quality and reduced the operation cost by 49.3% per year less than chlorine dosed only in water treatment plant to meet RC standard.The results prove adding chlorine in water distribution system based on the model can bring both technological and economic advancement.

  20. A comparative study on the effect of Curcumin and Chlorin-p6 on the transport of the LDS cation across a negatively charged POPG bilayer: Effect of pH

    Science.gov (United States)

    Varshney, G. K.; Kintali, S. R.; Gupta, P. K.; Das, K.

    2017-02-01

    We report the use of interface selective Second Harmonic generation technique to investigate the transport of the LDS cation across POPG liposomes in the pH range of 4.0 to 8.0 in the presence and absence of two amphiphilic drugs, Curcumin and Chlorin-p6 (Cp6). Our results show that bilayer permeability of liposomes is significantly affected by the presence of the drugs and pH of the medium as evidenced by significant changes in the transport kinetics of the LDS. Studies carried out in the pH range 4.0-8.0 show that while Cp6 significantly enhanced the transport of LDS at pH 4.0, the transport of the cation was seen to increase with increasing pH, with maximum effect at pH 7.4 for Curcumin. The pH dependent bilayer localization of both the drugs was investigated by conducting steady state FRET studies using DPH labeled lipids as donors. The FRET results and the relative population of the various ionic/nonionic species of the drugs at different pH suggest that distance dependent interaction between the various ionic species of the drugs and polar head groups of the lipid is responsible for the observed pH dependence enhancement of the drug induced membrane permeability. Another interesting observation was that the stability of Curcumin in presence of POPG liposomes was observed to degrade significantly near physiological pH (7.4 and 8.0). Although this degradation did not affect the liposome integrity, interestingly this was observed to enhance the transport of the LDS cation across the bilayer. That the degradation products of Curcumin are equally effective as the drug itself in enhancing the membrane permeability lends additional support to the current opinion that the bioactive degradation products of the drug may have a significant contribution to its observed pharmacological effects.

  1. Nutrients and neurodevelopment: lipids.

    Science.gov (United States)

    González, Horacio F; Visentin, Silvana

    2016-10-01

    Nutrients, lipids in particular, make up the central nervous system structure and play major functional roles: they stimulate development, migration, and nerve cell differentiation. They are part of gray matter, white matter, nerve nuclei, and synaptogenesis. Breast milk contains lipids which are crucial for infant brain development. The lipid profile of breast milk was used as a guideline for the development of breast milk substitutes. However, to date, no substitute has matched it. Complementary feeding should include docosahexaenoic acid, arachidonic acid, other polyunsaturated fatty acids, saturated fatty acids, and complex lipids found in milk fat. The lipid composition of breast milk depends on maternal intake and nutritional status during pregnancy and breast-feeding. It has a great impact on development. Our goal is to review scientific literature regarding the role of lipids on infant brain development and the importance of breast milk lipid composition, maternal diet, and complementary feeding.

  2. Science and policy in risk assessments of chlorinated ethenes.

    Science.gov (United States)

    Rudén, Christina

    2006-09-01

    In this article the use of data obtained from standardized experimental methods, for example, as specified in OECD guidelines for the testing of chemicals, epidemiology data, and mechanism data obtained from nonstandardized experimental methods in carcinogen risk assessment is scrutinized using the most recent risk assessments made by International Agency for Research on Cancer (IARC), the MAK(MAK)-Kommission, World Health Organization (WHO), European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC), and American Conference of Governmental Industrial Hygienists (ACGIH) for the four chlorinated ethenes as examples. The analysis shows that there was little controversy among these risk assessors about the interpretation of standardized animal data. On the other hand, they differ in their interpretation of epidemiology data, in particular in their assessment of statistical significance including the use of meta-analyses, and in quality evaluation of studies initiated on the basis of a priori concerns for carcinogenicity. The selection of mechanism data for species extrapolation is diverse among these risk assessors. Furthermore, in some cases they refrain from transparently motivating significant claims about mechanisms of toxicity by avoiding to give (explicit) references to the sources of information forming the basis of these claims or conclusions. This practice is not according to the scientific standards that should be required of a risk assessment document, and it makes it difficult to follow the argumentation and consequently to scrutinize the scientific accuracy of the conclusions drawn. In this article it is concluded that in some of these risk assessment documents, the use of mechanism data is not according to the scientific standards that should be required. It is furthermore concluded that if the use of mechanism data in these documents are representative of risk assessments in general, then there is an urgent need for further development and

  3. Lipid Structure in Triolein Lipid Droplets

    DEFF Research Database (Denmark)

    Chaban, Vitaly V; Khandelia, Himanshu

    2014-01-01

    Lipid droplets (LDs) are primary repositories of esterified fatty acids and sterols in animal cells. These organelles originate on the lumenal or cytoplasmic side of endoplasmic reticulum (ER) membrane and are released to the cytosol. In contrast to other intracellular organelles, LDs are composed...... of a mass of hydrophobic lipid esters coved by phospholipid monolayer. The small size and unique architecture of LDs makes it complicated to study LD structure by modern experimental methods. We discuss coarse-grained molecular dynamics (MD) simulations of LD formation in systems containing 1-palmitoyl-2...... to coarse-grained simulations, the presence of PE lipids at the interface has a little impact on distribution of components and on the overall LD structure. (4) The thickness of the lipid monolayer at the surface of the droplet is similar to the thickness of one leaflet of a bilayer. Computer simulations...

  4. Fate of free chlorine in drinking water during distribution in premise plumbing.

    Science.gov (United States)

    Zheng, Muzi; He, Chunguang; He, Qiang

    2015-12-01

    Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise plumbing. As the first effort to assessing the fate of chlorine in premise plumbing using actual premise plumbing pipe sections, three piping materials frequently used in premise plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three pipe materials tested. The most rapid chlorine decay was observed in copper pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free chlorine residual if copper piping is used. PVC pipes exhibited the least reactivity with free chlorine, indicative of the advantage of PVC as a premise plumbing material for maintaining free chlorine residual. The reactivity of copper piping with free chlorine was significantly hindered by the accumulation of pipe deposits. In contrast, the impact on chlorine decay by pipe deposits was not significant in galvanized iron and PVC pipes. Findings in this study are of great importance for the development of effective strategies for the control of free chlorine residual and prevention of microbiological contamination in premise plumbing.

  5. CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS

    Science.gov (United States)

    This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

  6. Complete Non-Radioactive Operability Tests for Cladding Hull Chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Emory D [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnson, Jared A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hylton, Tom D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brunson, Ronald Ray [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunt, Rodney Dale [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); DelCul, Guillermo Daniel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bradley, Eric Craig [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Spencer, Barry B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-04-01

    Non-radioactive operability tests were made to test the metal chlorination reactor and condenser and their accessories using batch chlorinations of non-radioactive cladding samples and to identify optimum operating practices and components that need further modifications prior to installation of the equipment into the hot cell for tests on actual used nuclear fuel (UNF) cladding. The operability tests included (1) modifications to provide the desired heating and reactor temperature profile; and (2) three batch chlorination tests using, respectively, 100, 250, and 500 g of cladding. During the batch chlorinations, metal corrosion of the equipment was assessed, pressurization of the gas inlet was examined and the best method for maintaining solid salt product transfer through the condenser was determined. Also, additional accessing equipment for collection of residual ash and positioning of the unit within the hot cell were identified, designed, and are being fabricated.

  7. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquife

  8. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and

  9. Effectiveness of chlorination and ozonation methods on pure ...

    African Journals Online (AJOL)

    2005-01-16

    Jan 16, 2005 ... Volume of the solvent acetone/tetrachloroethylene. (mℓ). V. Volume of .... several industrial activated sludge systems (Converti et al.,. 1995) ...... WHITE GC (1999) Handbook of Chlorination and Alternative Disin- fectants (4th ...

  10. Kinetics of Chlorine Decay in Water Distribution Systems

    Institute of Scientific and Technical Information of China (English)

    周建华; 薛罡; 赵洪宾; 汪永辉; 郭美芳

    2004-01-01

    A combined first and second-order model, which includes bulk decay and wall decay, was developed to describe chlorine decay in water distribution systems. In the model the bulk decay has complex relationships with total organic carbon (TOC), the initial chlorine concentration and the temperature. Except for the initial stages they can be simplified into a linear increase with TOC, a linear decrease with initial chlorine concentration and an exponential relationship with the temperature. The model also explains why chlorine decays rapidly in the initial stages. The parameters of model are determined by deriving the best fitness with experimental data. And the accuracy of model has been verified by using the experimental data and the monitoring data in a distribution system.

  11. CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS

    Science.gov (United States)

    This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

  12. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfectant byproducts (DNPS) at a pilot plant in Evansville, IN, that uses chlorine dioxide as a primary disinfectant. nconventional multispectral identification techniques (gas chromatography combined with high- and low-resolu...

  13. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE DISINFECTION BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfection byproducts (DBPs) at a pilot plant in Evansville, IN, which uses chlorine dioxide as a primary disinfectant. Unconventional multispectral identification techniques (gas chromatography combined with high- and low reso...

  14. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfectant byproducts (DNPS) at a pilot plant in Evansville, IN, that uses chlorine dioxide as a primary disinfectant. nconventional multispectral identification techniques (gas chromatography combined with high- and low-resolu...

  15. Modeling of residual chlorine in water distribution system

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Water quality within water distribution system may vary with both location and time. Water quality models are used to predict the spatial and temporal variation of water quality throughout water system. A model of residual chlorine decay in water pipe has been developed,given the consumption of chlorine in reactions with chemicals in bulk water, bio-films on pipe wall, in corrosion process, and the mass transport of chlorine from bulk water to pipe wall. Analytical methods of the flow path from water sources to the observed point and the water age of every observed node were proposed. Model is used to predict the decay of residual chlorine in an actual distribution system. Good agreement between calculated and measured values was obtained.

  16. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquife

  17. The role of natural chlorinated hydroquinone metabolites in ligninolytic fungi

    NARCIS (Netherlands)

    Teunissen, P.J.M.

    1999-01-01

    Ligninolytic Basidiomycetes have been reported to produce a wide variety of chloroaromatic compounds as secondary metabolites, which are structurally similar to environmental pollutants. Among these are chlorinated hydroquinone metabolites (CHM), such as 2-chloro-1,4-dimethoxybenzene

  18. Medium-chain chlorinated paraffins (MCCPs): a review of bioaccumulation potential in the aquatic environment.

    Science.gov (United States)

    Thompson, Roy; Vaughan, Martin

    2014-01-01

    Chlorinated paraffins (CPs) are high molecular weight organochlorine compounds that have been used in a variety of industrial applications for many years. Medium-chain chlorinated paraffins (MCCPs) (CAS 85535-85-9; Alkanes, C14-17 , chloro) are currently under investigation as potential persistent bioaccumulative toxic (PBT) compounds. In this article, the bioaccumulation potential of MCCPs is assessed using a tiered framework proposed after a recent Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop in 2008. The framework proposes the use of physicochemical properties and modeling assessment, bioconcentration/bioaccumulation (BCF/BAF) assessment, biomagnification (BMF) assessment, and trophic magnification factor (TMF) assessment. It is hoped that use of this framework could harmonize and improve the efficiency and effectiveness of the chemical substance evaluation screening process for PBT properties. When applied to MCCPs, the following conclusions were made: empirical physiochemical data is available negating the use of models; laboratory BCFs range from 1000 to 15 000 (growth-corrected lipid normalized values) for 2 MCCP structures; field BAFs were an order of magnitude higher than the trigger criterion for "B status possible"; although results may not meet acceptance criteria for field studies, laboratory-derived BMFs for a number of C14-17 chlorinated alkanes were less than the trigger value of 1 (based on whole-body concentrations) whereas field-derived BMFs were less than 1 (based on lipid corrected values [generally used for field data] excluding one measure for sculpin, [Cottus cognatus]-Diporeia that was based on only one detectable sample); and finally, TMFs were less than the trigger criterion value of 1, which are considered the most convincing evidence for bioaccumulative properties of a compound and the "Gold Standard" measure of bioaccumulation. This article also discusses the uncertainties surrounding the published data

  19. Assessment of the risk of transporting liquid chlorine by rail

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, W.B.

    1980-03-01

    This report presents the risk of shipping liquid chlorine by rail. While chlorine is not an energy material, there are several benefits to studying chlorine transportation risks. First, chlorine, like energy materials, is widely used as a feedstock to industry. Second, it is the major purification agent in municipal water treatment systems and therefore, provides direct benefits to the public. Finally, other risk assessments have been completed for liquid chlorine shipments in the US and Europe, which provide a basis for comparison with this study. None of the previous PNL energy material risk assessments have had other studies for comparison. For these reasons, it was felt that a risk assessment of chlorine transportation by rail could provide information on chlorine risk levels, identify ways to reduce these risks and use previous studies on chlorine risks to assess the strengths and weaknesses of the PNL risk assessment methodology. The risk assessment methodology used in this study is summarized. The methodology is presented in the form of a risk assessment model which is constructed for ease of periodic updating of the data base so that the risk may be reevaluated as additional data become available. The report is sectioned to correspond to specific analysis steps identified in the model. The transport system and accident environment are described. The response of the transport system to accident environments is described. Release sequences are postulated and evaluated to determine both the likelihood and possible consequences of a release. Supportive data and analyses are given in the appendices. The risk assessment results are related to the year 1985 to allow a direct comparison with other reports in this series.

  20. SCENARIOS EVALUATION TOOL FOR CHLORINATED SOLVENT MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; Brian02 Looney, B; Michael J. Truex; Charles J. Newell

    2006-08-16

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  1. Chlorine dioxide project allows Stora to clean up, use hardwoods

    Energy Technology Data Exchange (ETDEWEB)

    Butters, G.

    1988-10-01

    Effluent fouling into the Strait of Canso between Nova Scotia mainland and Cape Breton Island has caused Stora Forest Industries Ltd. to develop a $5.6 million solution to its chlorine and acid problems. In 1987, Stora produced about 160,000 tonnes of market pulp where their resource base increasingly consisted of hardwood. The company uses hardwood chips for a growing percentage of its annual pulp production and for its hog fuel boiler, but became faced with having to use more local hardwoods which contributes to the resin problem. Their solution was to construct a 12-tpd chlorine dioxide generator, a process using dry sodium chlorate added to concentrated H/sub 2/SO/sub 4/, The products are chlorine dioxide and highly concentrated sulphuric acid resulting from the elimination of water at the starting point. This will eliminate the acid effluent from the generator and the sulphuric acid will be recycled to the top of the chlorine dioxide generation process. In the new process, ClCO/sub 2/ replaces 70% of the chlorine in the first stage, with 100% substitution a goal. In addition to eliminating the chlorine, other benefits include an increase in pulp production, a nominal increase in pulp strength, lower production costs, and an economic incentive to harvest the area's mixed-wood stands.

  2. Zebra mussel control using periodic chlorine dioxide treatments

    Energy Technology Data Exchange (ETDEWEB)

    Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Coyle, J. [Central Illinois Public Service, Merdosia, IL (United States); Crone, D. [Illinois Power Company, Alton, IL (United States)] [and others

    1996-08-01

    This paper summarizes the EPRI report (TR-105202) on the same topic as well as presents changes in current thinking on the suitability (applicability) of chlorine dioxide for fouling control. Chlorine dioxide was tested as a zebra mussel biocide at two steam electric generating stations in Illinois and one in Indiana. The purpose of these studies was to determine the efficacy of chlorine dioxide in killing zebra mussels and to develop site specific treatment programs for the three utilities. The Electric Power Research Institute (EPRI) Zebra Mussel Consortium sponsored the testing of this recent use of chlorine dioxide. The raw water system at Central Illinois Public Service`s Meredosia Station, on the Illinois River, received applications of chlorine dioxide in April, July, and September 1994. The raw water system at Illinois Power Company`s Wood River Station, on the Mississippi River, received applications in July 1993, January, April, May, July, and September 1994. The Gallagher Station, on the Ohio River, was treated in July and October 1994. Chlorine dioxide was generated on-site and injected into the water intake structure. Both cooling and service water systems were treated at the facilities. 6 refs., 13 figs.

  3. Disinfection of swine wastewater using chlorine, ultraviolet light and ozone.

    Science.gov (United States)

    Macauley, John J; Qiang, Zhimin; Adams, Craig D; Surampalli, Rao; Mormile, Melanie R

    2006-06-01

    Veterinary antibiotics are widely used at concentrated animal feeding operations (CAFOs) to prevent disease and promote growth of livestock. However, the majority of antibiotics are excreted from animals in urine, feces, and manure. Consequently, the lagoons used to store these wastes can act as reservoirs of antibiotics and antibiotic-resistant bacteria. There is currently no regulation or control of these systems to prevent the spread of these bacteria and their genes for antibiotic resistance into other environments. This study was conducted to determine the disinfection potential of chlorine, ultraviolet light and ozone against swine lagoon bacteria. Results indicate that a chlorine dose of 30 mg/L could achieve a 2.2-3.4 log bacteria reduction in lagoon samples. However, increasing the dose of chlorine did not significantly enhance the disinfection activity due to the presence of chlorine-resistant bacteria. The chlorine resistant bacteria were identified to be closely related to Bacillus subtilis and Bacillus licheniformis. A significant percentage of lagoon bacteria were not susceptible to the four selected antibiotics: chlortetracycline, lincomycin, sulfamethazine and tetracycline (TET). However, the presence of both chlorine and TET could inactivate all bacteria in one lagoon sample. The disinfection potential of UV irradiation and ozone was also examined. Ultraviolet light was an effective bacterial disinfectant, but was unlikely to be economically viable due to its high energy requirements. At an ozone dose of 100 mg/L, the bacteria inactivation efficiency could reach 3.3-3.9 log.

  4. Kinetics and mechanism of the chlorine dioxide-trithionate reaction.

    Science.gov (United States)

    Cseko, György; Horváth, Attila K

    2012-03-22

    The trithionate-chlorine dioxide reaction has been studied spectrophotometrically in a slightly acidic medium at 25.0 ± 0.1 °C in acetate/acetic acid buffer monitoring the decay of chlorine dioxide at constant ionic strength (I = 0.5 M) adjusted by sodium perchlorate. We found that under our experimental conditions two limiting stoichiometries exist and the pH, the concentration of the reactants, and even the concentration of chloride ion affects the actual stoichiometry of the reaction that can be augmented by an appropriate linear combination of these limiting processes. It is also shown that although the formal kinetic order of trithionate is strictly one that of chlorine dioxide varies between 1 and 2, depending on the actual chlorine dioxide excess and the pH. Moreover, the otherwise sluggish chloride ion, which is also a product of the reaction, slightly accelerates the initial rate of chlorine dioxide consumption and may therefore act as an autocatalyst. In addition to that, overshoot-undershoot behavior is also observed in the [(·)ClO(2)]-time curves in the presence of chloride ion at chlorine dioxide excess. On the basis of the experiments, a 13-step kinetic model with 6 fitted kinetic parameter is proposed by nonlinear parameter estimation. © 2012 American Chemical Society

  5. Chlorobenzene outputs from combustion of chlorinated organic and inorganic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Green, A.E.S.; Vitali, J.A.; Miller, T.L. [Univ. of Florida, Gainesville, FL (United States)

    1994-12-31

    The authors consider the gas phase formation of chlorinated benzenes and phenols as precursors of chlorinated dioxins and furans from the combustion of solid fuels containing organically bound chlorine. The model investigated is intended to apply to the combustion of medical waste, municipal waste and coals containing chlorine. Assuming a temperature-time profile drawn from incinerator experiments, the authors use kinetic modeling with known reaction rates to further investigate four models of chlorinated benzene formation. Since reaction rates for most chlorination processes are now known, the authors choose simple systems of reaction rates that yield outputs that can be made approximately compatible with results of the Pittsfield-Vicon incinerator and Clean Combustion Technology Laboratory experiments. The authors also consider recent measurements of HCI emissions from crematoria and the implication of this work with respect to the benefits of material substitution in medical and municipal waste incineration. These benefits should also accompany the dechlorination of coals. The authors note the disparity between the prevailing USA position and the emerging position of Germany on the issue of halogenated plastics. The authors also note that Europe and Asia are beginning to address solid fuel issues as a consolidated discipline. This pattern should be helpful in broadening the understanding of solid fuels combustion processes and in ferreting out erroneous data and conclusions. This is important in view of the recent concern about the role of low dioxin exposure levels on fetal development and the immune system.

  6. Prompt gamma analysis of chlorine in concrete for corrosion study

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2006-02-15

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine {gamma}-rays and calcium {gamma}-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine {gamma}-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  7. Prompt gamma analysis of chlorine in concrete for corrosion study.

    Science.gov (United States)

    Naqvi, A A; Nagadi, M M; Al-Amoudi, O S B

    2006-02-01

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine gamma-rays and calcium gamma-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine gamma-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  8. Fish tissue lipid-C:N relationships for correcting ä13C values and estimating lipid content in aquatic food web studies

    Science.gov (United States)

    Normalizing 13C values of animal tissue for lipid content is necessary to accurately interpret food web relationships from stable isotope analysis. This is because lipids are 13C-depleted relative to proteins and carbohydrates, and because lipid content varies among speci...

  9. Maternal transfer of emerging brominated and chlorinated flame retardants in European eels

    Energy Technology Data Exchange (ETDEWEB)

    Sühring, Roxana, E-mail: roxana.suehring@hzg.de [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Freese, Marko [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Schneider, Mandy [Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Schubert, Sophia; Pohlmann, Jan-Dag [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Alaee, Mehran [Water Science and Technology Directorate, Environment Canada, Burlington, Ontario, L7R4A6 Canada (Canada); Wolschke, Hendrik [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Hanel, Reinhold [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Ebinghaus, Ralf [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Marohn, Lasse [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany)

    2015-10-15

    The European eel (Anguilla anguilla) is regarded as a critically endangered species. Scientists are in agreement that the “quality of spawners” is a vital factor for the survival of the species. This quality can be impaired by parasites, disease and pollution. Especially endocrine disrupting organic chemicals pose a potential threat to reproduction and development of offspring. To our knowledge, the findings in this publication for the first time describe maternal transfer of contaminants in eels. We analysed the concentrations of in total 53 polybrominated diphenyl ethers (PBDEs) and their halogenated substitutes in muscle, gonads and eggs of artificially matured European eels and in muscle and gonads of untreated European eels that were used for comparison. We found evidence that persistent organic pollutants such as PBDEs, as well as their brominated and chlorinated substitutes are redistributed from muscle tissue to gonads and eggs. Concentrations ranged from 0.001 ng g{sup −1} ww for sum Dechlorane metabolites (DPMA, aCL{sub 10}DP, aCl{sub 11}DP) to 2.1 ng g{sup −1} ww for TBA in eggs, 0.001 ng g{sup −1} ww for Dechlorane metabolites to 9.4 ng g{sup −1} ww for TBA in gonads and 0.002 ng g{sup −1} ww for Dechlorane metabolites to 54 ng g{sup −1} ww for TBA in muscle tissue. Average egg muscle ratios (EMRs) for compounds detectable in artificially matured eels from both Schlei Fjord and Ems River ranged from 0.01 for Dechlorane 602 (DDC-DBF) to 10.4 for PBEB. Strong correlations were found between flame retardant concentrations and lipid content in the analysed tissue types, as well as transfer rates and octanol–water partitioning coefficient, indicating that these parameters were the driving factors for the observed maternal transfer. Furthermore, indications were found, that TBP-DBPE, TBP-AE, BATE and TBA have a significant uptake from the surrounding water, rather than just food and might additionally be formed by metabolism or

  10. Occurrences of nitrosamines in chlorinated and chloraminated drinking water in three representative cities, China.

    Science.gov (United States)

    Luo, Qian; Wang, Donghong; Wang, Zijian

    2012-10-15

    An investigation of the occurrence of nine nitrosamines in drinking water following different water treatment processes was conducted using samples from seven drinking water treatment plants in three cities and tap waters in one city in China. The total nitrosamine levels ranged from not detected (n.d.) to 43.45 ng/L. The species and concentrations of the nine nitrosamines varied with disinfection methods and source waters. N-nitrosodimethylamine (NDMA), which is the nitrosamines of greatest concern, was identified in raw water, disinfecting water, finished water and tap water samples, ranging from 0.8 to 21.6, 0.12 to 24.2, n.d. to 8.8, and n.d. to 13.3 ng/L, respectively. Chloramination alone produced the most significant amounts of NDMA, while ozonation followed by chloramination led to moderately reduced levels. Additionally, chlorination produced relatively less NDMA, while low pressure ultraviolet radiation followed by chlorination could also significantly reduce them. Total organic carbon is one of the most important factors influencing nitrosamines formation in disinfecting water. In contrast, the addition of chlorine following any other disinfection was found to increase the formation of the other eight species of nitrosamines. The three nitrosamines recommended for monitoring by the US EPA were detected in the tap water samples, but most were present at levels below those that pose a risk to human health. Nevertheless, the occurrence and concentration of nitrosamines regulated in the Drinking Water Contaminant Candidate List could cause some potential human effects and therefore warrant attention.

  11. Polynuclear aromatic and chlorinated hydrocarbons in mussels from the coastal zone of Ushuaia, Tierra del Fuego, Argentina.

    Science.gov (United States)

    Amin, Oscar A; Comoglio, Laura I; Sericano, José L

    2011-03-01

    Mussels (Mytilus edulis chilensis) were collected from 12 coastal locations in Ushuaia Bay, Argentina, and the surrounding area in October 1999 and again in October 2003. Concentrations of polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and selected chlorinated pesticides were determined to assess the impact of a fast-growing population in the area. Total PAH concentrations ranged from 2.24 to an extremely high concentration of 2,420 µg/g lipid measured in mussels collected near an oil jetty used to discharge to shore storage tanks. The composition of PAHs in these samples indicates that the source of these compounds inside Ushuaia Bay is predominantly petrogenic, with some pyrogenic background, whereas mostly pyrogenic-related PAHs were evident in areas outside the bay. Total concentrations of PCBs ranged between 12.8 and 8,210 ng/g lipid, with the highest concentration, detected inside Ushuaia harbor, representing a 10-fold increase when compared with historical data. Chlorinated pesticides were detected at comparatively lower concentrations, with 4-4'- 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene being the most common. The aggressive increase in population and related activities observed in the city of Ushuaia over the last two decades might have affected the environmental quality of the local bay. Moreover, the oceanographic and atmospheric conditions existing in Ushuaia Bay and surrounding areas may favor the accumulation and long-term presence of these organic pollutants in all compartments of this fragile environment. Copyright © 2011 SETAC.

  12. The synergistic effect of Escherichia coli inactivation by sequential disinfection with low level chlorine dioxide followed by free chlorine.

    Science.gov (United States)

    Yang, Wu; Yang, Dong; Zhu, Sui-Yi; Chen, Bo-Yan; Huo, Ming-Xin; Li, Jun-Wen

    2012-12-01

    To the best of our knowledge, there was little information available on pathogen removal using low level disinfectant followed by free chlorine in sequential disinfection (SD). This study investigated Escherichia coli inactivation by four types of disinfection: single step disinfection (SSD), SD, traditional sequential disinfection (TSD) and mixed disinfectant disinfection (MDD). Results indicated that SD had higher ability to inactivate E. coli than the others, indicating there was a positive synergistic effect on chlorine disinfection by prior dosing with a low level of chlorine dioxide (ClO(2)). The ONPG assay suggested that the permeability of cell wall rather than the viability of E. coli were changed under 0.02 mg/l ClO(2) treatment. The coexistence of residual ClO(2) and free chlorine also plays an active synergistic effect. Additionally, temperature had a positive effect on E. coli inactivation in SD, while inactivation was reduced in alkaline compared to neutral and acidic conditions.

  13. Purification of highly chlorinated dioxins degrading enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, K.; Furuichi, T.; Koike, K.; Kuboshima, M. [Hokkaido Univ. (Japan). Division of Environment Resource Engineering, Graduate School of Engineering

    2004-09-15

    Soil contamination caused by dioxins in and around sites of incinerators for municipal solid waste (MSW) is a concern in Japan. For example, scattering wastewater from a wet gas scrubber at an MSW incinerator facility in Nose, Osaka caused soil and surface water contamination. The concentration of dioxins in the soil was about 8,000 pg-TEQ/g. Other contamination sites include soils on which fly ash has been placed directly or improperly stored and landfill sites that have received bottom and fly ash over a long period. Some countermeasures are required immediately at these dioxins-contaminated sites. We have previously developed bioreactor systems for dioxin-contaminated water and soil. We have shown that a fungus, Pseudallescheria boydii (P. boydii), isolated from activated sludge treating wastewater that contained dioxins, has the ability to degrade highly chlorinated dioxins. A reaction product of octachlorinated dibenzo-p-dioxin (OCDD) was identified as heptachlorinated dibenzo-p-dioxin. Therefore, one of the pathways for degradation of OCDD by this fungus was predicted to be as follows: OCDD is transformed by dechlorination and then one of the remaining aromatic rings is oxidized. To apply P. boydii to on-site technologies (e.g., bioreactor systems), as well as in situ technologies, enzyme treatment using a dioxin-degrading enzyme from P. boydii needs to be developed because P. boydii is a weak pathogenic fungus, known to cause opportunistic infection. As a result, we have studied enzyme purification of nonchlorinated dioxin, namely, dibenzo-pdioxin (DD). However, we did not try to identify enzymes capable of degrading highly chlorinated dioxins. This study has elucidated a method of enzyme assay for measuring OCDD-degrading activity, and has attempted to purify OCDD-degrading enzymes from P. boydii using enzyme assay. In addition, as first step toward purifying 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-TCDD degradation tests were carried out

  14. The Ins and Outs of Lipid Flip-Flop.

    Science.gov (United States)

    Allhusen, John S; Conboy, John C

    2017-01-17

    Our current view of cellular membranes centers on the fluid-mosaic model, which envisions the cellular membrane as a "liquidlike" bilayer of lipids, cholesterol, and proteins that freely diffuse in two dimensions. In stark contrast, the exchange of materials between the leaflets of a bilayer was presumed to be prohibited by the large enthalpic barrier associated with translocating hydrophilic materials, such as a charged lipid headgroup, through the hydrophobic membrane core. This static picture with regard to lipid translocation (or "flip-flop" as it is affectionately known) has been a long-held belief in the study of membrane dynamics. The current accepted membrane model invokes specific protein flippase (inward moving), floppase (outward moving), and scramblase (bidirectional) enzymes that assist in the movement of lipids between the leaflets of cellular membranes. The low rate of protein-free lipid flip-flop has also been a cornerstone of our understanding of the bilateral organization of cellular membrane components, specifically the asymmetric distribution of lipid species found in the luminal and extracellular leaflets of the plasma membrane of eukaryotic cells. Much of the previous work contributing to our current understanding of lipid flip-flop has utilized fluorescent- or spin-labeled lipids. However, there is growing evidence that these lipid probes do not accurately convey the dynamics and thermodynamics of native (unlabeled) lipid motion. This Account summarizes our research efforts directed toward developing a deep physical and chemical understanding of protein-free lipid flip-flop in phospholipid membrane models using sum-frequency vibrational spectroscopy (SFVS). Our use of SFVS enables the direct measurement of native lipid flip-flop in model membranes. In particular, we have explored the kinetic rates and activation thermodynamics of lipid translocation as a means of deciphering the underlying chemical and physical directors governing this

  15. Efficacy of chlorine, acidic electrolyzed water and aqueous chlorine dioxide solutions to decontaminate Escherichia coli O157:H7 from lettuce leaves

    Science.gov (United States)

    This study compared the efficacy of chlorine (20 – 200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20 – 200 ppm chlorite ion concentration, Sanova), and aqueous chlorine dioxide (20 – 200 ppm chlorite ion concentration, TriNova) washes in reducing population...

  16. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ren, Hongqiang, E-mail: hqren@nju.edu.cn; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p = 0.007–0.014, n = 6),as well as contact time (p = 0.0001, n = 10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30–1.49 logs) could be achieved at FC dosage of 30 mg L{sup −1}. The transformation kinetic data for ARGs removal (log C{sub 0} / C) followed the second-order reaction kinetic model with FC dosage (R{sup 2} = 0.6829–0.9999) and contact time (R{sup 2} = 0.7353–8634), respectively. Higher ammonia nitrogen (NH{sub 3}–N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl{sub 2}:NH{sub 3}–N ratio was over 7.6:1, a significant reduction of ARGs (1.20–1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36–0.40 at a fluence of 249.5 mJ cm{sup −2}, which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters. - Highlights: • Chlorine is more effective than UV irradiation in removing ARGs from MWTP effluent. • The chlorination reaction followed the second-order reaction kinetic model. • Higher NH{sub 3}–N contents result in lower ARGs removal in the chlorination process. • FC is more effective than CC on the inactivation of ARGs. • UV irradiation followed by chlorination shows high efficiency in removing ARGs.

  17. Site-selective photofragmentation of chlorinated polymeric films observed around the chlorine K-edge

    Energy Technology Data Exchange (ETDEWEB)

    Arantes, C., E-mail: csilva@inmetro.gov.br [Divisão de Metrologia de Materiais, Instituto Nacional de Metrologia, Qualidade e Tecnologia, Xerém 25250-020, Duque de Caxias, RJ (Brazil); Mendes, L.A.V. [Instituto de Física, Universidade Federal da Bahia, Ondina, 40210-340 Salvador, BA (Brazil); Pinho, R.R. [Departamento de Física-ICE, Universidade Federal de Juiz de Fora, Campus Universitário, 36036-330 Juiz de Fora, MG (Brazil); Ferreira, M. [PEMM/COPPE, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-972 Rio de Janeiro, RJ (Brazil); Souza, G.G.B. de; Rocha, A.B.; Rocco, M.L.M. [Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-909 Rio de Janeiro, RJ (Brazil)

    2013-03-29

    Highlights: ► PVC and PVDC were studied by PSID and NEXAFS techniques at the Chlorine 1s-edge. ► PVC film presented isotope ratio of 3:1 in the PSID spectrum. ► Cl{sup +} ion yield curves reproduce the photoabsorption spectrum for both polymers. ► Site-selectivity of C–Cl bond breaking due to an efficient spectator Auger decay. - Abstract: Photon stimulated ion desorption (PSID) and Near-edge X-ray absorption fine structure (NEXAFS) studies have been performed on poly(vinyl chloride) (PVC) and poly(vinyl dichloride) (PVDC) around the chlorine 1s-edge. Experiments were performed using a synchrotron source operating in the single-bunch mode and a time-of-flight mass spectrometry for ion analysis. Cl{sup +} ion yields, as a function of the photon energy, reproduce the photoabsorption spectrum, showing significant increase at the 1s-resonance. Edge-jump ratios, defined as the ratio between edge-jumps (intensity ratio of the yields between above and below the absorption edge) of two different transitions, for Cl{sup +} ion yields were much higher than the equivalent electron yields, indicating site-selectivity in C–Cl bond breaking for both polymers, as a result of efficient spectator Auger decay. The expected isotope ratio of 3:1 for chlorine was measured for PVC. The interpretation of the NEXAFS spectrum was assisted by quantum mechanical calculations at a multireference perturbation theory level.

  18. Factors affecting the formation of nitrogenous disinfection by-products during chlorination of aspartic acid in drinking water.

    Science.gov (United States)

    Chen, Wei; Liu, Zhigang; Tao, Hui; Xu, Hang; Gu, Yanmei; Chen, Zhaolin; Yu, Jingjing

    2017-01-01

    The formation of emerging nitrogenous disinfection by-products (N-DBPs) from the chlorination of aspartic acid (Asp) was investigated. The yield of dichloroacetonitrile (DCAN) was higher than other N-DBPs, such as dichloroacetamide(DCAcAm) and chloropicrin (TCNM) during the chlorination of Asp. The formation of DCAN, DCAcAm, and TCNM all showed a trend of first increasing and then decreasing during the chlorination of Asp with increasing contact time. The dosage of chlorine had an impact on the formation of DCAN, DCAcAm, and TCNM. The highest yields of DCAN and DCAcAm appeared when the Cl2/Asp molar ratio was about 20, the yield of TCNM increased with increasing the Cl2/Asp molar ratio from 5 to 30 and TCNM was not produced when the ratio was less than 5. Cyanogen chloride (CNCl) was detected when the Cl2/Asp molar ratio was lower than 5. N-DBPs formation was influenced by pH. DCAN formation increased with increasing pH from 5 to 6 and then decreased with increasing pH from 6 to 9, but DCAcAm and TCNM increased with increasing pH from 5 to 8 and then decreased. Higher temperatures reduced the formation of DCAN and DCAcAm, but increased TCNM formation. DCAN and DCAcAm formation decreased, and relatively stable TCNM formation increased, with increasing free chlorine contact time during chloramination. N-nitrosodimethylamine (NDMA) was produced during chloramination of Asp and increased with prolonged chloramination contact time. The presence of bromide ions enhanced the yields of haloacetonitriles and shifted N-DBPs to more brominated species.

  19. Combustion of chlorinated volatile organic compounds (VOCs) using bimetallic chromium-copper supported on modified H-ZSM-5 catalyst.

    Science.gov (United States)

    Abdullah, Ahmad Zuhairi; Bakar, Mohamad Zailani Abu; Bhatia, Subhash

    2006-02-28

    The paper reports on the performance of chromium or/and copper supported on H-ZSM-5(Si/Al = 240) modified with silicon tetrachloride (Cr1.5/SiCl4-Z, Cu1.5/SiCl4-Z and Cr1.0Cu0.5/SiCl4-Z) as catalysts in the combustion of chlorinated VOCs (Cl-VOCs). A reactor operated at a gas hourly space velocity (GHSV) of 32,000 h(-1), a temperature between 100 and 500 degrees C with 2500 ppm of dichloromethane (DCM), trichloromethane (TCM) and trichloroethylene (TCE) is used for activity studies. The deactivation study is conducted at a GHSV of 3800 h(-1), at 400 degrees C for up to 12 h with a feed concentration of 35,000 ppm. Treatment with silicon tetrachloride improves the chemical resistance of H-ZSM-5 against hydrogen chloride. TCM is more reactive compared to DCM but it produces more by-products due to its high chlorine content. The stabilization of TCE is attributed to resonance effects. Water vapor increases the carbon dioxide yield through its role as hydrolysis agent forming reactive carbocations and acting as hydrogen-supplying agent to suppress chlorine-transfer reactions. The deactivation of Cr1.0Cu0.5/SiCl4-Z is mainly due to the chlorination of its metal species, especially with higher Cl/H feed. Coking is limited, particularly with DCM and TCM. In accordance with the Mars-van Krevelen model, the weakening of overall metal reducibility due to chlorination leads to a loss of catalytic activity.

  20. Microbial perchlorate reduction: A precise laboratory determination of the chlorine isotope fractionation and its possible biochemical basis

    Science.gov (United States)

    Ader, Magali; Chaudhuri, Swades; Coates, John D.; Coleman, Max

    2008-05-01

    Perchlorate-reducing bacteria fractionate chlorine stable isotopes giving a powerful approach to monitor the extent of microbial consumption of perchlorate in contaminated sites undergoing remediation or natural perchlorate containing sites. This study reports the full experimental data and methodology used to re-evaluate the chlorine isotope fractionation of perchlorate reduction in duplicate culture experiments of Azospira suillum strain PS at 37 °C (Δ 37Cl Cl --ClO 4-) previously reported, without a supporting data set by Coleman et al. [Coleman, M.L., Ader, M., Chaudhuri, S., Coates, J.D., 2003. Microbial Isotopic Fractionation of Perchlorate Chlorine. Appl. Environ. Microbiol. 69, 4997-5000] in a reconnaissance study, with the goal of increasing the accuracy and precision of the isotopic fractionation determination. The method fully described here for the first time, allows the determination of a higher precision Δ 37Cl Cl --ClO 4- value, either from accumulated chloride content and isotopic composition or from the residual perchlorate content and isotopic composition. The result sets agree perfectly, within error, giving average Δ 37Cl Cl --ClO 4- = - 14.94 ± 0.15‰. Complementary use of chloride and perchlorate data allowed the identification and rejection of poor quality data by applying mass and isotopic balance checks. This precise Δ 37Cl Cl --ClO 4- value can serve as a reference point for comparison with future in situ or microcosm studies but we also note its similarity to the theoretical equilibrium isotopic fractionation between a hypothetical chlorine species of redox state + 6 and perchlorate at 37 °C and suggest that the first electron transfer during perchlorate reduction may occur at isotopic equilibrium between an enzyme-bound chlorine and perchlorate.

  1. Ficusmicrochlorin A-C, two new methoxy lactone chlorins and an anhydride chlorin from the leaves of Ficus microcarpa.

    Science.gov (United States)

    Lin, Huan-You; Chiu, Hsi-Lin; Lu, Te-Ling; Tzeng, Chih-Ying; Lee, Tzong-Huei; Lee, Ching-Kuo; Shao, Yi-Yuan; Chen, Chiy-Rong; Chang, Chi-I; Kuo, Yueh-Hsiung

    2011-01-01

    Two new methoxy lactone chlorins ficusmicrochlorin A (1) and ficusmicrochlorin B (2), and one new anhydride chlorin ficusmicrochlorin C (3), along with eight known pheophytins were isolated from the leaves of Ficus microcarpa. Their structures were determined by the extensive 1D- and 2D-NMR techniques. New pheophytin compound was rarely obtained from natural sources. In the past ten years, only three new natural pheophytins were characterized.

  2. Plasma lipid concentrations for some Brazilian lizards.

    Science.gov (United States)

    Gillett, M P; Lima, V L; Costa, J C; Sibrian, A M

    1979-01-01

    1. Plasma concentrations of cholesterol, cholesteryl esters, phospholipids and triglycerides were determined for ten species of Brazilian lizards, Iguana iguana, Tropidurus torquatos and T. semitaeniatus (Iguanidae), Tupinambis teguixin, Ameiva ameiva and Cnemidophorus ocellifer (Teiidae), Mabuya maculata (Scincidae), Hemidactylus mabouia (Gekkonidae), Amphisbaenia vermicularis and Leposternon polystegum (Amphisbaenidae). 2. Considerable inter- and intra-species variations in plasma lipid concentrations were observed. 3. The percentage of total cholesterol esterified and the individual phospholipid composition of plasma were relatively constant for each species. 4. Over 60% of the cholesteryl esters present in plasma from three species each of iguanid and teiid lizards were polyenoic.

  3. Fate of PBDEs during food processing: Assessment of formation of mixed chlorinated/brominated diphenyl ethers and brominated dioxins/furans.

    Science.gov (United States)

    Roszko, Marek; Szymczyk, Krystyna; Jędrzejczak, Renata

    2015-01-01

    The aim of this study was to evaluate effects of food processing on PBDE levels, in particular influence of heat treatment on degradation of PBDEs, including possible formation of chlorinated diphenyl ethers or brominated dioxins/furans as degradation products. It was shown that PBDEs heated in the presence of chlorine (from either organic or inorganic sources) formed mixed chlorinated/brominated diphenyl ethers. However, no PCDEs were formed in the presence of lipids. Lipid medium increased stability of PBDEs exposed to UV irradiation. Profile of congeners formed in result of the debromination reaction was significantly different than profiles observed by some other authors in aliphatic organic solvents. Grilling processes increased concentrations (calculated on the fresh product basis) of the studied compounds by 4-8/22-34% for electric/coal grill, respectively. Depending on the congener and on the applied heat treatment, PBDE mass in pork meat after grilling dropped by 26-53%. No detectable quantities of either brominated dioxins or furans were formed during thermal processing of food containing typical levels of PBDEs.

  4. Polyene-lipids: a new tool to image lipids

    DEFF Research Database (Denmark)

    Kuerschner, Lars; Ejsing, Christer S.; Ekroos, Kim

    2005-01-01

    conjugated double bonds as a new type of lipid tag. Polyene-lipids exhibit a unique structural similarity to natural lipids, which results in minimal effects on the lipid properties. Analyzing membrane phase partitioning, an important biophysical and biological property of lipids, we demonstrated...... the superiority of polyene-lipids to both NBD- and BODIPY-tagged lipids. Cells readily take up various polyene-lipid precursors and generate the expected end products with no apparent disturbance by the tag. Applying two-photon excitation microscopy, we imaged the distribution of polyene-lipids in living...

  5. Transformation of cefazolin during chlorination process: products, mechanism and genotoxicity assessment.

    Science.gov (United States)

    Li, Liping; Wei, Dongbin; Wei, Guohua; Du, Yuguo

    2013-11-15

    Large quantities of cephalosporins have entered into aquatic environment in recent years, posing potential adverse effect to human health and ecological safety. In this study, cefazolin, one of widely used cephalosporins, was targeted to explore its transformation behaviors in chlorination disinfection process. With the help of ultra high performance liquid chromatography and high resolution mass spectroscopy, one chlorinated product and four oxidation products were detected in cefazolin chlorination system. The corresponding transformation pathways of cefazolin were proposed. Two kinds of reactions occurred in chlorination system, one was oxidation of thioether-sulfur to sulfoxide and di-sulfoxide, and the other was base-catalyzed electrophilic substitution of alpha-H of amide by chlorine atom. The pH value determined the occurrence of reaction types, and increasing chlorine dose promoted transformation of cefazolin. More importantly, genotoxicity in SOS/umu assay had an elevation after chlorination, which might be attributed to the formation of chlorinated product and sulfoxide during chlorination process.

  6. Stable Chlorine Isotope Study: Application to Early Solar System Materials

    Science.gov (United States)

    Mala,ira. M/; Nyquist, L. E.; Reese, Y.; Shih, C-Y; Fujitani, T.; Okano, O.

    2010-01-01

    A significantly large mass fractionation between two stable chlorine isotopes is expected during planetary processes In addition, in view of the isotopic heterogeneity of other light elements, the chlorine isotopes can potentially be used as a tracer for the origins and evolutionary processes of early solar system materials. Due to analytical difficulties, however, current chlorine isotope studies on planetary materials are quite controversial among IRMS (gas source mass spectrometry) and/or TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1-3]. Although a cross-calibration of IRMS and TIMS indicates that both techniques are sufficiently consistent with each other [4], some authors have claimed that the Cl-37/Cl-35 ratio of geological samples obtained by TIMS technique are, in general, misleadingly too high and variable compared to those of IRMS [3]. For example, almost no differences of Cl isotope composition were observed among mantle materials and carbonaceous meteorites by [3]. On the other hand, according to more recent IRMS work [2], significant Cl isotope variations are confirmed for mantle materials. Therefore, additional careful investigation of Cl isotope analyses are now required to confirm real chlorine isotope variations for planetary materials including carbonaceous chondrites [5]. A significantly large mass fractionation between two stable chlorine isotopes is expected during planetary processes In addition, in view of the isotopic heterogeneity of other light elements, the chlorine isotopes can potentially be used as a tracer for the origins and evolutionary processes of early solar system materials. Due to analytical difficulties, however, current chlorine isotope studies on planetary materials are quite controversial among IRMS (gas source mass spectrometry) and/or TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1-3]. Although a cross-calibration of IRMS and TIMS indicates that both techniques are sufficiently consistent with each

  7. Electrochemical Membrane Reactors for Sustainable Chlorine Recycling

    Directory of Open Access Journals (Sweden)

    Ulrich Kunz

    2012-07-01

    Full Text Available Polymer electrolyte membranes have found broad application in a number of processes, being fuel cells, due to energy concerns, the main focus of the scientific community worldwide. Relatively little attention has been paid to the use of these materials in electrochemical production and separation processes. In this review, we put emphasis upon the application of Nafion membranes in electrochemical membrane reactors for chlorine recycling. The performance of such electrochemical reactors can be influenced by a number of factors including the properties of the membrane, which play an important role in reactor optimization. This review discusses the role of Nafion as a membrane, as well as its importance in the catalyst layer for the formation of the so-called three-phase boundary. The influence of an equilibrated medium on the Nafion proton conductivity and Cl crossover, as well as the influence of the catalyst ink dispersion medium on the Nafion/catalyst self-assembly and its importance for the formation of an ionic conducting network in the catalyst layer are summarized.

  8. Electrochemical Membrane Reactors for Sustainable Chlorine Recycling

    Science.gov (United States)

    Vidakovic-Koch, Tanja; Martinez, Isai Gonzalez; Kuwertz, Rafael; Kunz, Ulrich; Turek, Thomas; Sundmacher, Kai

    2012-01-01

    Polymer electrolyte membranes have found broad application in a number of processes, being fuel cells, due to energy concerns, the main focus of the scientific community worldwide. Relatively little attention has been paid to the use of these materials in electrochemical production and separation processes. In this review, we put emphasis upon the application of Nafion membranes in electrochemical membrane reactors for chlorine recycling. The performance of such electrochemical reactors can be influenced by a number of factors including the properties of the membrane, which play an important role in reactor optimization. This review discusses the role of Nafion as a membrane, as well as its importance in the catalyst layer for the formation of the so-called three-phase boundary. The influence of an equilibrated medium on the Nafion proton conductivity and Cl− crossover, as well as the influence of the catalyst ink dispersion medium on the Nafion/catalyst self-assembly and its importance for the formation of an ionic conducting network in the catalyst layer are summarized. PMID:24958294

  9. Effect of soil moisture on chlorine deposition.

    Science.gov (United States)

    Hearn, John; Eichler, Jeffery; Hare, Christopher; Henley, Michael

    2014-02-28

    The effect of soil moisture on chlorine (Cl(2)) deposition was examined in laboratory chamber experiments at high Cl(2) exposures by measuring the concentration of chloride (Cl(-)) in soil columns. Soil mixtures with varying amounts of clay, sand, and organic matter and with moisture contents up to 20% (w/w) were exposed to ≈3×10(4)ppm Cl(2) vapor. For low water content soils, additional water increased the reaction rate as evidenced by higher Cl(-) concentration at higher soil moisture content. Results also showed that the presence of water restricted transport of Cl(2) into the soil columns and caused lower overall deposition of Cl(2) in the top 0.48-cm layer of soil when water filled ≈60% or more of the void space in the column. Numerical solutions to partial differential equations of Fick's law of diffusion and a simple rate law for Cl(2) reaction corroborated conclusions derived from the data. For the soil mixtures and conditions of these experiments, moisture content that filled 30-50% of the available void space yielded the maximum amount of Cl(2) deposition in the top 0.48cm of soil. Published by Elsevier B.V.

  10. Chlorinated hydrocarbon contaminants in arctic marine mammals.

    Science.gov (United States)

    Norstrom, R J; Muir, D C

    1994-09-16

    By 1976, the presence of chlorinated hydrocarbon contaminants (CHCs) had been demonstrated in fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), hooded seal (Cystophora cristata), bearded seal (Erignathus barbatus), walrus (Obdobenus rosmarus divergens), beluga (Delphinapterus leucas), porpoise (Phocoena phocoena) and polar bear (Ursus maritimus) in various parts of the Arctic. In spite of this early interest, very little subsequent research on contaminants in Arctic marine mammals was undertaken until the mid-1980s. Since that time, there has been an explosion of interest, resulting in a much expanded data base on contaminants in Arctic marine mammals. Except in the Russian Arctic, data have now been obtained on the temporospatial distribution of PCBs and other contaminants in ringed seal, beluga and polar bear. Contaminants in narwhal (Monodon monoceros) have also now been measured. On a fat weight basis, the sum of DDT-related compounds (S-DDT) and PCB levels are lowest in walrus (St. Lawrence and ringed seal in the Baltic Sea, indicate that overall contamination of the Arctic marine ecosystem is 10-50 times less than the most highly contaminated areas in the northern hemisphere temperate latitude marine environment. Geographic distribution of residue levels in polar bears indicates a gradual increase from Alaska east to Svalbard, except PCB levels are significantly higher in eastern Greenland and Svalbard. Information on temporal trends is somewhat contradictory.(ABSTRACT TRUNCATED AT 400 WORDS)

  11. Environmental behaviour of short-chain chlorinated paraffins in aquatic and terrestrial ecosystems of Ny-Ålesund and London Island, Svalbard, in the Arctic.

    Science.gov (United States)

    Li, Huijuan; Fu, Jianjie; Pan, Wenxiao; Wang, Pu; Li, Yingming; Zhang, Qinghua; Wang, Yawei; Zhang, Aiqian; Liang, Yong; Jiang, Guibin

    2017-07-15

    The environmental behaviour of short-chain chlorinated paraffins (SCCPs) was investigated in both aquatic and terrestrial ecosystems in the Arctic. The mean concentrations of SCCPs in the aquatic and terrestrial samples were 178.9ng/g dry weight (dw) and 157.2ng/g dw, respectively. Short carbon chain (C10) and less-chlorinated (Cl6) congener groups were predominant in the Arctic samples, accounting for 48.6% and 34.8% of the total SCCPs, respectively. The enrichment of lighter SCCP congener groups (i.e., fewer chlorine atoms with shorter carbon chain lengths) indicated that the fractionation process occurred during long-range transport. The biomagnification factor (BMF) was 0.46 from gammarid to cod, which indicated that the SCCPs did not biomagnify between these two species. The soil-vegetation bioaccumulation factor (BAF) of SCCPs was 29.9, and C13 and Cl7, 8 congener groups tended to accumulate in the terrestrial vegetation. Regression analysis (BAFs=10.9×#C+5.6×#Cl-125.2, R=0.53, P<0.01) showed that the number of carbon and chlorine atoms influenced the bioaccumulative behaviour of SCCPs and suggested that the number of carbon atoms had a greater influence on the BAFs of SCCPs in the terrestrial ecosystem than did the number of chlorine atoms.

  12. Mechanistic aspects of ingested chlorine dioxide on thyroid function: impact of oxidants on iodide metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Bercz, J.P.; Jones, L.L.; Harrington, R.M.; Bawa, R.; Condie, L.

    1986-11-01

    Toxicological studies dealing with recent findings of health effects of drinking water disinfectants are reviewed. Experiments with monkeys and rodents indicate that the biological activity of ingested disinfectants is expressed via their chemical interaction with the mucosal epithelia, secretory products, and nutritional contents of the alimentary tract. Evidence exists that a principal partner of this redox interaction is the iodide of nutritional origin that is ubiquitous in the gastrointestinal tract. Thus the observation that subchronic exposure to chlorine dioxide (ClO/sub 2/) in drinking water decreases serum thyroxine levels in mammalian species can be best explained with changes produced in the chemical form of the bioavailable iodide. Ongoing and previously reported mechanistic studies indicate that oxidizing agents such as chlorine-based disinfectants oxidize the basal iodide content of the gastrointestinal tract. The resulting reactive iodine species readily attaches to organic matter by covalent bonding. Evidence suggests that the extent to which such iodinated organics are formed is proportional to the magnitude of the electromotive force and stoichiometry of the redox couple between iodide and the disinfectant. Because the extent of thyroid uptake of the bioavailable iodide does not decrease during ClO/sub 2/ ingestion, it seems that ClO/sub 2/ does not cause iodide deficiency of sufficient magnitude to account for the decease in hormonogenesis. Absorption of one or more of iodinated molecules, e.g., nutrient, hormones, or cellular constituents of the alimentary tract having thyromimetic or thyroid inhibitory properties, is a better hypothesis for the effects seen.

  13. Photochemical partitioning of the reactive nitrogen and chlorine reservoirs in the high-latitude stratosphere

    Science.gov (United States)

    Kawa, S. R.; Fahey, D. W.; Heidt, L. E.; Pollock, W. H.; Solomon, S.; Anderson, D. E.; Loewenstein, M.; Proffitt, M. H.; Margitan, J. J.; Chan, K. R.

    1992-01-01

    The correlated set of measurements in the lower stratosphere from polar missions of the NASA ER-2 is used to derive partitioning of the major components of the reactive nitrogen and inorganic chlorine reservoirs. The results provide a consistent method for comparing distributions, and hence the controlling processes, between different areas of the near-polar regions. Clear evidence of the effects of heterogeneous processes in the atmosphere is found. Values for NO2, ClONO2, N2O5, and Cl2O2 are derived in a simplified steady-state model based on in situ NO, ClO, O3, temperature, and pressure measurements, laboratory-measured reaction rates; and modeled photodissociation rates. Values for the reservoir totals are independently derived from measurements of N2O, organic chlorine, and total reactive nitrogen. The relative abundances of the measured and derived species within the reservoirs are calculated, and the longer-lived species HCl and HNO3 are estimated as the residuals of their respective reservoirs.

  14. A systematic survey of lipids across mouse tissues

    Science.gov (United States)

    Jain, Mohit; Ngoy, Soeun; Sheth, Sunil A.; Swanson, Raymond A.; Rhee, Eugene P.; Liao, Ronglih; Clish, Clary B.; Mootha, Vamsi K.

    2014-01-01

    Lipids are a diverse collection of macromolecules essential for normal physiology, but the tissue distribution and function for many individual lipid species remain unclear. Here, we report a mass spectrometry survey of lipid abundance across 18 mouse tissues, detecting ∼1,000 mass spectrometry features, of which we identify 179 lipids from the glycerolipids, glycerophospholipids, lysophospholipids, acylcarnitines, sphingolipids, and cholesteryl ester classes. Our data reveal tissue-specific organization of lipids and can be used to generate testable hypotheses. For example, our data indicate that circulating triglycerides positively and negatively associated with future diabetes in humans are enriched in mouse adipose tissue and liver, respectively, raising hypotheses regarding the tissue origins of these diabetes-associated lipids. We also integrate our tissue lipid data with gene expression profiles to predict a number of substrates of lipid-metabolizing enzymes, highlighting choline phosphotransferases and sterol O-acyltransferases. Finally, we identify several tissue-specific lipids not present in plasma under normal conditions that may be of interest as biomarkers of tissue injury, and we show that two of these lipids are released into blood following ischemic brain injury in mice. This resource complements existing compendia of tissue gene expression and may be useful for integrative physiology and lipid biology. PMID:24518676

  15. Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

    Directory of Open Access Journals (Sweden)

    Takashi Furukawa

    2017-07-01

    Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

  16. CHLORINATION OF AMINO ACIDS: REACTION PATHWAYS AND REACTION RATES.

    Science.gov (United States)

    How, Zuo Tong; Linge, Kathryn; Busetti, Francesco; Joll, Cynthia A

    2017-03-15

    Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected by-products. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modelling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4x104 M-1 s-1) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9x102 M-1 s-1), although some N-monochlorovaline degraded into isobutyraldehyde (1.0x10-4 s-1). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3x10-4 s-1) and N-chloroisobutyraldimine (1.2x10-4 s-1). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odour threshold concentration, resulting in aesthetic challenges and an unknown health risk.

  17. Comparison of chlorine and chlorine dioxide toxicity of fathead minnows and bluegill

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.; Soracco, R.J.; Mayack, L.A.; Shealy, R.L.; Broadwell, T.L.; Steffen, R.F.

    1983-01-01

    The comparative toxicity of total residual chlorine (TRC) and chlorine dioxide (ClO/sub 2/) was evaluated by conducting 96 h flow-through bioassays with three types of fish. The fish were subjected to an intermittent exposure regime in which biocide residuals were present for approximately 2-h periods beginning at 0, 24, 48 and 72 h into the tests. These conditions simulated the antifouling procedure (1 h day/sup -1/ biocide addition) used to control biofouling of nuclear reactor heat exchangers at the Savannah River Plant near Aiken, South Carolina. LC/sub 50/ values showed that ClO/sub 2/ was approximately 2 to 4 times more toxic than TRC to: (1) juvenile and 1-year-old fathead minnows (Pimphales promelas); and (2) young-of-the-year bluegill (Lepomis macrochirus). The TRC mean 96-h LC/sub 50/ values were: 0.08 mg l/sup -1/ for juvenile fathead minnows, 0.35 mg l/sup -1/ for adult fathead minnows and 0.44 mg l/sup -1/ for young-of-the-year bluegills. The ClO/sub 2/ mean LC/sub 50/ values were: 0.02 mg l/sup -1/ for juvenile fathead minnows, 0.17 mg l/sup -1/ for adult fathead minnows and 0.15 mg l/sup -1/ for young-of-the-year bluegills. 31 references, 1 figure, 3 tables.

  18. Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein

    Energy Technology Data Exchange (ETDEWEB)

    Vrablik, Tracy L. [Washington State Univ., Pullman, WA (United States); Petyuk, Vladislav A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Larson, Emily M. [Washington State Univ., Pullman, WA (United States); Smith, Richard D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Watts, Jennifer [Washington State Univ., Pullman, WA (United States)

    2015-06-27

    Lipid droplets are cytoplasmic organelles that store neutral lipids for membrane synthesis and energy reserves. In this study, we characterized the lipid and protein composition of purified C. elegans lipid droplets. These lipid droplets are composed mainly of triacylglycerols, surrounded by a phospholipid monolayer composed primarily of phosphatidylcholine and phosphatidylethanolamine. The fatty acid composition of the triacylglycerols was rich in fatty acid species obtained from the dietary E. coli, including cyclopropane fatty acids and cis-vaccenic acid. Unlike other organisms, C. elegans lipid droplets contain very little cholesterol or cholesterol esters. Comparison of the lipid droplet proteomes of wild type and high-fat daf-2 mutant strains shows a relative decrease of MDT-28 abundance in lipid droplets isolated from daf-2 mutants. Functional analysis of lipid droplet proteins identified in our proteomic studies indicated an enrichment of proteins required for growth and fat homeostasis in C. elegans.

  19. The physiology of lipid storage and use in reptiles.

    Science.gov (United States)

    Price, Edwin R

    2016-06-27

    Lipid metabolism is central to understanding whole-animal energetics. Reptiles store most excess energy in lipid form, mobilise those lipids when needed to meet energetic demands, and invest lipids in eggs to provide the primary source of energy to developing embryos. Here, I review the mechanisms by which non-avian reptiles store, transport, and use lipids. Many aspects of lipid absorption, transport, and storage appear to be similar to birds, including the hepatic synthesis of lipids from glucose substrates, the transport of triglycerides in lipoproteins, and the storage of lipids in adipose tissue, although adipose tissue in non-avian reptiles is usually concentrated in abdominal fat bodies or the tail. Seasonal changes in fat stores suggest that lipid storage is primarily for reproduction in most species, rather than for maintenance during aphagic periods. The effects of fasting on plasma lipid metabolites can differ from mammals and birds due to the ability of non-avian reptiles to reduce their metabolism drastically during extended fasts. The effect of fasting on levels of plasma ketones is species specific: β-hydroxybutyrate concentration may rise or fall during fasting. I also describe the process by which the bulk of lipids are deposited into oocytes during vitellogenesis. Although this process is sometimes ascribed to vitellogenin-based transport in reptiles, the majority of lipid deposition occurs via triglycerides packaged in very-low-density lipoproteins (VLDLs), based on physiological, histological, biochemical, comparative, and genomic evidence. I also discuss the evidence for non-avian reptiles using 'yolk-targeted' VLDLs during vitellogenesis. The major physiological states - feeding, fasting, and vitellogenesis - have different effects on plasma lipid metabolites, and I discuss the possibilities and potential problems of using plasma metabolites to diagnose feeding condition in non-avian reptiles.

  20. Electrochemical reduction characteristics and the mechanism of chlorinated hydrocarbons at the copper electrode

    Institute of Scientific and Technical Information of China (English)

    XU Wenying; GAO Tingyao; ZHOU Rongfeng; MA Lumin

    2007-01-01

    The electrochemical reduction characteristies of chlorinated hyrdrocarbons were investigated by cyclic voltammetry technique.The reduction mechanism and activity of the chlorinated hydrocarbons at the copper electrode were explored.The relationship between the structure of chlorinated hydrocarbons and their reductive activity were discussed.The experimental results showed that chlorinated alkanes and a portion of chlorinated aromatic hydrocarbons could be reduced directly at the copper electrode.However,chlorinated aromatic hydrocarbons were not easy to reduce at the copper electrode.The results provided a theoretical basis for the catalyzed iron inner electrolysis method.

  1. Study on metal corrosion caused by chlorine dioxide of various purities

    Institute of Scientific and Technical Information of China (English)

    崔崇威; 黄君礼; 许晶

    2004-01-01

    Weight lost method was used to comparatively study the corrosion behavior of four different metals under the dosage of chlorine dioxide, chlorine and their mixture respectively. The experimental results indicated that chlorine causes the most serious corrosion of carbon steel, and the higher the concentration of chlorine, the more serious the corrosion. On the contras, metals corrosion is the least serious in the case of chlorine dioxide.The results further revealed that chlorine dioxide is the most effective water treatment reagent, making it the best choice to use extensively in circulated cooling water disinfection and corrosion control.

  2. Do Lipids Retard the Evaporation of the Tear Fluid?

    DEFF Research Database (Denmark)

    Rantamaki, A. H.; Javanainen, M.; Vattulainen, I.

    2012-01-01

    . Lipids were applied to an air-water interface, and the evaporation rate through the lipid layer was defined as water loss from the interface. A thick layer of olive oil and a monolayer of long-chain alcohol were used as controls. The artificial TFLLs were composed of 1 to 4 lipid species: polar...... phosphatidylcholine (PC), nonpolar cholesteryl ester, triglycerides, and wax ester (WE). Brewster angle microscopy (BAM) and interfacial shear rheometry (ISR) were used to assess the lateral structure and shear stress response of the lipid layers, respectively. RESULTS. Olive oil and long-chain alcohol decreased...

  3. Multiple-barrier disinfection by chlorination and UV irradiation for desalinated drinking waters: chlorine photolysis and accelerated lamp-sleeve fouling effects.

    Science.gov (United States)

    Wait, Isaac W

    2008-11-01

    Experiments were conducted to quantify interaction effects between UV irradiation and chlorination for desalinated drinking water. The rate of chlorine photolysis in desalinated water was characterized using a low-pressure UV lamp and chlorine doses typical of drinking water treatment and was found to be lower than reported photolysis rates for treated surface water. Results indicate that, for most desalinated water applications, reduction in free chlorine is likely to be limited, but, depending on the UV dose used, not necessarily negligible. Investigation of the potential for reactor lamp-sleeve fouling included mineral speciation and solubility modeling and showed that chlorination of desalinated water before UV disinfection may increase lamp-sleeve fouling, particularly for point-of-use reactors. UV irradiation before chlorination may minimize fouling. Overall results point to the variable nature of UV lamp-sleeve fouling and chlorine photolysis and an intrinsic dependence on local water chemistry conditions.

  4. Lipid bilayers and interfaces

    NARCIS (Netherlands)

    Kik, R.A.

    2007-01-01

    In biological systems lipid bilayers are subject to many different interactions with other entities. These can range from proteins that are attached to the hydrophilic region of the bilayer or transmembrane proteins that interact with the hydrophobic region of the lipid bilayer. Interaction between

  5. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection.

    Science.gov (United States)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju; Ren, Hongqiang; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p=0.007-0.014, n=6),as well as contact time (p=0.0001, n=10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30-1.49 logs) could be achieved at FC dosage of 30 mg L(-1). The transformation kinetic data for ARGs removal (log C0/C) followed the second-order reaction kinetic model with FC dosage (R(2)=0.6829-0.9999) and contact time (R(2)=0.7353-8634), respectively. Higher ammonia nitrogen (NH3-N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl2:NH3-N ratio was over 7.6:1, a significant reduction of ARGs (1.20-1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36-0.40 at a fluence of 249.5 mJ cm(-2), which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters.

  6. Rapid Determination of HAAs Formation Potential of the Reaction of Humic Acid with Chlorine or Chlorine Dioxide

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-liang; GE Yuan-xin; ZHANG Rong-hua; MA Hong-mei; HAO Jian-fu

    2007-01-01

    On the basis of gas chromatography(GC) coupled with a short capillary column and an electron capture detector(ECD), a simple and rapid method for the determination of five haloacetic acids(HAAs) in drinking water was developed by the optimization of derivation conditions and the modification of gas chromatographic program. HAAs formation potential(HAAFP) of the reaction of humic acid with chlorine was determined via this method. The major advantages of the method are the simplicity of chromatographic temperature program and the short run time of GC. Dichloroacetic acid(DCAA) and Trichloroacetic acid(TCAA), which were detected in the determination of HAAFP, were rapidly formed in the first 72 h of the reaction of humic acid with chlorine. HAAFP of the reaction of humic acid with chlorine increased with the increase in the concentrations of humic acid and chlorine. The average HAAFP of the reaction of humic acid with chlorine was 39.9 μg/mg TOC under the experimental conditions. When the concentration of humic acid was 4 mg/L, the concentration of HAAs, which were produced in the reaction of humic acid with chorine, may exceed MCL of 60 μg/L HAAs as the water quality standards for urban water supply of China and the first stage of US EPA disin