WorldWideScience

Sample records for chloramines

  1. Inactivation of Helicobacter pylori by Chloramination

    Science.gov (United States)

    Three strains of Helicobacter pylori (H. pylori) were studied to determine their resistance to chloramination. H. pylori is an organism listed on the U.S. Environmental Protection Agency’s (USEPA) Contaminant Control List (CCL). H. pylori was exposed to 2ppm of pre-formed monoc...

  2. Formation of organic chloramines during chlor(am)ination and UV/chlor(am)ination of algae organic matter in drinking water.

    Science.gov (United States)

    Zhang, Tian-Yang; Lin, Yi-Li; Xu, Bin; Cheng, Tuo; Xia, Sheng-Ji; Chu, Wen-Hai; Gao, Nai-Yun

    2016-10-15

    Surface water are frequently subjected to problems of algal blooms and release of algae organic matter (AOM) from the algae cells, which cause many water quality issues. This study investigated the formation of organic chloramines and nitrogenous disinfection by-products (N-DBPs) during chlor(am)ination and UV/chlor(am)ination of AOM in drinking water. AOM caused higher organic chloramine formation than humic acid and fulvic acid during chlor(am)ination. The formation of organic chloramines increased first and then decreased with the increase of free chlorine dosage, but kept increasing with the increase of NH2Cl dosage. During AOM chlorination, the formation of organic chloramines kept decreasing as the reaction time went by, and the maximum organic chloramine proportion (79.1%) in total chlorine occurred at 8 h. However, during AOM chloramination, the formation of organic chloramines increased first, decreased in the following and then increased again as the reaction time went by, and the maximum organic chloramine proportion (22.1%) in total chlorine occurred at 24 h. UV irradiation pretreatment did not effectively influence organic chloramine formation during AOM chlor(am)ination, but accelerated the degradation of organic chloramines during chloramination. Besides, UV pretreatment enhanced the formation of N-DBPs during the subsequent chlor(am)ination of AOM, especially dichloroacetonitrile.

  3. Chloramine-induced anaphylaxis while showering: a case report

    Directory of Open Access Journals (Sweden)

    D’Alò Simona

    2012-09-01

    Full Text Available Abstract Introduction Sodium-N-chlorine-p-toluene sulfonamide, commonly known as chloramine-T, is a derivative of chlorine which is widely used as a disinfectant. For many years, chloramine-T has been described as a cause of immediate-type hypersensitivity, especially with regard to asthma and rhinitis, and as a cause of occupational dermatoses in cleaning personnel in hospitals, although no anaphylactic reaction has yet been reported. Hence, to the best of our knowledge we present the first case of anaphylaxis to chloramine-T with evidence of specific immunoglobulin E antibodies. Case presentation We describe the case of a 25-year-old Caucasian woman who was in good health and with a negative history for atopy, including no respiratory symptoms of rhinitis or asthma, and with no professional exposure to chloramine-T. She, while showering, applied a chloramine-T solution to a skin area with folliculitis on her leg, and within a few minutes developed generalized urticaria and angioedema, followed by vomiting and collapse with loss of consciousness. A skin prick test with a chloramine-T solution at 10mg/mL concentration was positive, and specific immunoglobulin E to chloramine-T was quantified at a value of 2.9 optical density as measured by the enzyme allergosorbent test technique. Conclusion The strict cause-effect relationship and the results of the skin test and the in vitro test make certain the causative role of chloramine-T in this case of anaphylaxis. This suggests that chloramine-T, based on its wide use as a disinfectant, should be considered a possible cause in anaphylaxis of unknown origin.

  4. NDMA formation by chloramination of ranitidine: Kinetics and mechanism

    KAUST Repository

    Le Roux, Julien

    2012-10-16

    The kinetics of decomposition of the pharmaceutical ranitidine (a major precursor of NDMA) during chloramination was investigated and some decomposition byproducts were identified by using high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). The reaction between monochloramine and ranitidine followed second order kinetics and was acid-catalyzed. Decomposition of ranitidine formed different byproducts depending on the applied monochloramine concentration. Most identified products were chlorinated and hydroxylated analogues of ranitidine. In excess of monochloramine, nucleophilic substitution between ranitidine and monochloramine led to byproducts that are critical intermediates involved in the formation of NDMA, for example, a carbocation formed from the decomposition of the methylfuran moiety of ranitidine. A complete mechanism is proposed to explain the high formation yield of NDMA from chloramination of ranitidine. These results are of great importance to understand the formation of NDMA by chloramination of tertiary amines. © 2012 American Chemical Society.

  5. Reaction of protein chloramines with DNA and nucleosides

    DEFF Research Database (Denmark)

    Hawkins, Clare L; Pattison, David I; Davies, Michael Jonathan

    2002-01-01

    Stimulated phagocyte cells produce the oxidant HOCl, via the release of the enzyme myeloperoxidase and hydrogen peroxide. HOCl is important in bacterial cell killing, but excessive or misplaced generation can damage the host tissue and may lead to the development of certain diseases such as cance......, 50-80% of the HOCl is predicted to react with histone lysine and histidine residues to yield chloramines. The yield and stability of such chloramines predicted by these modelling studies agrees well with experimental data. Decomposition of these species gives protein-derived, nitrogen......-centred radicals, probably on the lysine side chains, as characterized by the EPR and spin-trapping experiments. It is shown that isolated lysine, histidine, peptide and protein chloramines can react with plasmid DNA to cause strand breaks. The protection against such damage afforded by the radical scavengers...... to give nucleobase radicals. Further evidence for the formation of such covalent cross-links has been obtained from experiments performed using (3)H-lysine and (14)C-histidine chloramines. These results are consistent with the predictions of the kinetic model and suggest that histones are major targets...

  6. Organic chloramines in drinking water: An assessment of formation, stability, reactivity and risk.

    Science.gov (United States)

    How, Zuo Tong; Linge, Kathryn L; Busetti, Francesco; Joll, Cynthia A

    2016-04-15

    Although organic chloramines are known to form during the disinfection of drinking water with chlorine, little information is currently available on their occurrence or toxicity. In a recent in vitro study, some organic chloramines (e.g. N-chloroglycine) were found to be cytotoxic and genotoxic even at micromolar concentrations. In this paper, the formation and stability of 21 different organic chloramines, from chlorination of simple amines and amino acids, were studied, and the competition between 20 amino acids during chlorination was also investigated. For comparison, chlorination of two amides was also conducted. The formation and degradation of selected organic chloramines were measured using either direct UV spectroscopic or colorimetric detection. Although cysteine, methionine and tryptophan were the most reactive amino acids towards chlorination, they did not form organic chloramines at the chlorine to precursor molar ratios that were tested. Only 6 out of the 21 organic chloramines formed had a half-life of more than 3 h, although this group included all organic chloramines formed from amines. A health risk assessment relating stability and reactivity data from this study to toxicity and precursor abundance data from the literature indicated that only N-chloroglycine is likely to be of concern due to its stability, toxicity and abundance in water. However, given the stability of organic chloramines formed from amines, more information about the toxicity and precursor abundance for these chloramines is desirable.

  7. Effect of X-ray Contrast Media, Chlorination, and Chloramination on Zebrafish Development

    Science.gov (United States)

    Effect of X-ray Contrast Media, Chlorination, and Chloramination on Zebrafish Development Little is known about the vertebrate developmental toxicity of chlorinated or chloraminated drinking water (DW), iodinated X-ray contrast media (ICM, a common contaminate of DW) or how the c...

  8. Preparation and evaluation of radio labelled recombinant human interleukin 2 by improved chloramine T method

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Masahiro; Kominami, Goro; Kono, Masao (Shionogi and Co. Ltd., Osaka (Japan). Research Lab.)

    1991-03-01

    Iodination by improved chloramine T method was investigated. Iodine was activated with very small quantity of chloramine T (21 fold excess to iodine in molar ratio) and then recombinant interleukin-2 (rIL-2) was added to the mixture. Characteristics of the labelled rIL-2 after purification by reversed-phase HPLC was superior to those by usual chloramine T method or lactoperoxidase method. The specific activity was 0.74-1.11 MBq/{mu}g and the immunoreactivity, biological activity and binding ability to rIL-2 receptors were similar to the intrinsic rIL-2. The improved chloramine T method is useful for iodination of unstable peptides and proteins. (author).

  9. Modeling the formation of TOCl, TOBr and TOI during chlor(am)ination of drinking water.

    Science.gov (United States)

    Zhu, Xiaohu; Zhang, Xiangru

    2016-06-01

    The use of chlorine and chloramines in drinking water disinfection may produce innumerable halogenated disinfection byproducts (DBPs). Because of the impossibility of measuring the concentration and evaluating the toxicity of each individual halogenated DBP in a water sample, total organic halogen (TOX) as a collective parameter and a toxicity indicator for all the halogenated DBPs has been gaining popularity in recent years. TOX can be divided into total organic chlorine (TOCl), total organic bromine (TOBr), and total organic iodine (TOI). Previously, the authors' group studied the formation kinetics of TOCl and TOBr in chlor(am)ination using two models. In this study, we further explored the formation kinetics of TOI as well as TOCl and TOBr during chlor(am)ination by carefully selecting a series of iodine-related reactions and incorporating them into the two kinetic models. The models well predicted the levels of TOCl, TOBr, TOI, and total chlorine residual during chlorination and chloramination of simulated raw waters. According to the modeling results, 57.1-73.6% of the total generated iodinated DBPs in chlorination was converted to their chlorinated and brominated analogues by the substitution with hypochlorous acid and hypobromous acid; while in chloramination, with the presence of excessive monochloramine, the formed hypoiodous acid might react with monochloramine to form an iodine-substituted intermediate (proposed as chloroiodamine), which was responsible for 41.4-49.8% of the total generated iodinated DBPs, and meantime 51.9-52.6% of the total generated iodinated DBPs underwent deiodination via the base-catalyzed hydrolysis. The models were successfully applied in determining the lag time between the dosages of chlorine and ammonia, a challenging issue in chlorine-chloramine sequential treatment. This study provided important insights into kinetic reactions that control the formation of overall halogenated DBPs in chlor(am)ination.

  10. [Formation of Disinfection By-Products During Chlor(am)ination of Danjiangkou Reservoir Water and Comparison of Disinfection Processes].

    Science.gov (United States)

    Zhang, Min-sheng; Xu, Bin; Zhang, Tian-yang; Cheng, Tuo; Xia, Sheng-ji; Chu, Wen-hai

    2015-09-01

    This study discussed the formation of volatile carbonaceous disinfection by-products (DBPs) and nitrogenous DBPs during chlor(am) ination of Danjingkou Reservoir water which was the source of the Middle Route Project of South-to-North Water Diversion Project. The effects of disinfection methods, disinfectant dosage, reaction time, pH values and bromide ion concentration were investigated. And the disinfection parameters were optimized. Four DBPs, including chloroform (CF), bromodichloromethane (BDCM), dichloroacetonitrile(DCAN) and trichloronitromethane(TCNM), were observed during the chlorination. But only CF and TCNM were detected during the chloramination of water. The disinfection by-product (DBP) concentration from chlorination is 7. 5 times higher than that from chloramination, and the yield of DBPs from short time chlorination then chloramination is in between the first two methods. All kinds of DBPs detected increased with the dosage of increasing chlorine, but the increases slowed down when the dosage was higher than 2 mg . L -1. The formation of CF varied a little as the dosage of chloramine increasing. TCNM was detected when the chloramine dosage was greater than 2 mg . L -1. As reaction time going on, chlorine decayed much faster than chloramine, while DBP formation under chlorination was faster than that of chloramination. THM produced by chlorine increased with the increasing pH, while chloramination showed no obvious changes. As the bromide ion increasing, the species of DBPs transformed from chlorinated DBPs to brominated ones, and the total yield of DBPs increased during both chlorination and chloramination, but the former one was obviously more than that of the latter one. In order to reduce the risk of DBP formation, the chloramination is suggested in the treatment of water from Danjiangkou Reservoir. And if chlorination is applied, the disinfectant dosage should be controlled seriously.

  11. Chloramination of nitrogenous contaminants (pharmaceuticals and pesticides): NDMA and halogenated DBPs formation

    OpenAIRE

    Le Roux, Julien; Gallard, Hervé; Croué, Jean-Philippe

    2011-01-01

    ©IWA Publishing 2011. The definitive peer-reviewed and edited version of this article is published in Water Research 45(10), Pages 3164–3174, 2011, DOI: 10.1016/j.watres.2011.03.035 and is available at www.iwapublishing.com.; International audience; Disinfection with chloramines is often used to reduce the production of regulated disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). However, chloramination can lead to the formation of N-nitrosamines, incl...

  12. Impact of Chloramination on the Development of Laboratory-Grown Biofilms Fed with Filter-Pretreated Groundwater

    KAUST Repository

    Ling, Fangqiong

    2013-01-01

    This study evaluated the continuous impact of monochloramine disinfection on laboratory-grown biofilms through the characterization of biofilm architecture and microbial community structure. Biofilm development and disinfection were achieved using CDC (Centers for Disease Control and Prevention) biofilm reactor systems with polyvinyl chloride (PVC) coupons as the substratum and sand filter-pretreated groundwater as the source of microbial seeding and growth nutrient. After 2 weeks of growth, the biofilms were subjected to chloramination for 8 more weeks at concentrations of 7.5±1.4 to 9.1±0.4 mg Cl2 L-1. Control reactors received no disinfection during the development of biofilms. Confocal laser scanning microscopy and image analysis indicated that chloramination could lead to 81.4-83.5% and 86.3-95.6% reduction in biofilm biomass and thickness, respectively, but could not eliminate biofilm growth. 16S rRNA gene terminal restriction fragment length polymorphism analysis indicated that microbial community structures between chloraminated and non-chloraminated biofilms exhibited different successional trends. 16S rRNA gene pyrosequencing analysis further revealed that chloramination could select members of Actinobacteria and Acidobacteria as the dominant populations, whereas natural development leads to the selection of members of Nitrospira and Bacteroidetes as dominant biofilm populations. Overall, chloramination treatment could alter the growth of multi-species biofilms on the PVC surface, shape the biofilm architecture, and select a certain microbial community that can survive or proliferate under chloramination.

  13. Dichloroacetonitrile and dichloroacetamide can form independently during chlorination and chloramination of drinking waters, model organic matters, and wastewater effluents.

    Science.gov (United States)

    Huang, Huang; Wu, Qian-Yuan; Hu, Hong-Ying; Mitch, William A

    2012-10-01

    The increasing usage of organic nitrogen-rich wastewater- or algal-impacted waters, and chloramines for secondary disinfection, raises concerns regarding the formation of haloacetonitriles, haloacetamides and other nitrogenous disinfection byproducts (N-DBPs). Previous research obtained contradictory results regarding the relative importance of chlorination or chloramination for promoting these byproducts, but applied chlorine and chloramines at different doses and exposure periods. Additionally, mechanistic work, mostly using model precursors, suggested that haloacetonitrile and haloacetamide formation should be correlated because hydrolysis of haloacetonitriles forms haloacetamides. In this work, the formation of dichloroacetonitrile (DCAN) and dichloroacetamide (DCAcAm) were compared across a range of chlorine and chloramine exposures for drinking waters, wastewater effluents, algal extracellular polymeric substances (EPS), NOM isolates and model precursors. While chlorination favored formation of DCAN over DCAcAm, chloramination nearly always formed more DCAcAm than DCAN, suggesting the existence of haloacetamide formation pathways that are independent of the hydrolysis of haloacetonitriles. Experiments with asparagine as a model precursor also suggested DCAcAm formation without a DCAN intermediate. Application of (15)N-labeled monochloramine indicated initial rapid formation of both DCAN and DCAcAm by pathways where the nitrogen originated from organic nitrogen precursors. However, slower formation occurred by pathways involving chloramine incorporation into organic precursors. While wastewater effluents and algal EPS tended to be more potent precursors for DCAN during chlorination, humic materials were more potent precursors for DCAcAm during chlorination and for both DCAN and DCAcAm during chloramination. These results suggest that, rather than considering haloacetamides as haloacetonitrile hydrolysis products, they should be treated as a separate N

  14. Effects of ozone pretreatment on the formation of disinfection by-products and its associated bromine substitution factors upon chlorination/chloramination of Tai Lake water.

    Science.gov (United States)

    Wang, Fangyuan; Ruan, Mengyong; Lin, Hongjun; Zhang, Yu; Hong, Huachang; Zhou, Xiaoling

    2014-03-15

    This study investigated the effects of preozonation on disinfection by-products (DBPs) formation during chlorination and chloramination of the water collected from Tai Lake. Results showed that the high ozone dose (0.6-1.0 mg O₃/mg DOC) pretreatment reduced the yields of trihaloacetic acids (reduced 62-63% in chlorination), dihaloacetonitriles (reduced 53-55% and 14-26% in chlorination and chloramination, respectively) and trihaomethanes (reduced 19% in chloramination), but markedly increased the formation of halonitromethanes (increased 4.7-5.6 times in chlorination and 2.1-2.7 times in chloramination), haloketones (increased 4.8-7.1 times in chlorination and 2.5-2.9 times in chloramination) and dihaloacetic acids (increased 1.5-2.4 times in chlorination and 0.3-0.6 times in chloramination). Thus the high ozone dose pretreatment should be avoided during chlorination/chloramination of Tai Lake water. Also, chloramination (with and without preozonation) produced much lower DBPs yields as compared with chlorination (with and without preozonation), indicating that chloramine was a better choice to control the DBPs yields. Further analysis also revealed that the bromine substitution factors (BSFs) of DBPs varied with disinfection mode. In chlorinamination, the BSFs generally showed a decrease trend with the ozone dose, yet in chlorination, the BSFs mostly exhibited first an increase and then a decrease trend. Moreover, the BSFs of DBPs in chloramination (with or without preozonation) were dominantly lower than those in chlorination (with or without preozonation).

  15. Draft Genome Sequences of Six Mycobacterium immunogenum, Strains Obtained from a Chloraminated Drinking Water Distribution System Simulator

    Science.gov (United States)

    We report the draft genome sequences of six Mycobacterium immunogenum isolated from a chloraminated drinking water distribution system simulator subjected to changes in operational parameters. M. immunogenum, a rapidly growing mycobacteria previously reported as the cause of hyp...

  16. Chloramination of nitrogenous contaminants (pharmaceuticals and pesticides): NDMA and halogenated DBPs formation.

    Science.gov (United States)

    Le Roux, Julien; Gallard, Hervé; Croué, Jean-Philippe

    2011-05-01

    Disinfection with chloramines is often used to reduce the production of regulated disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). However, chloramination can lead to the formation of N-nitrosamines, including N-nitrosodimethylamine (NDMA), a probable human carcinogen. Previous research used dimethylamine (DMA) as a model precursor of NDMA, but certain widely used tertiary dimethylamines (e.g. the pharmaceutical ranitidine) show much higher conversion rates to NDMA than DMA. This study investigates the NDMA formation potential of several tertiary amines including pharmaceuticals and herbicides. The reactivity of these molecules with monochloramine (NH(2)Cl) is studied through the formation of NDMA, and other halogenated DBPs such as haloacetonitriles (HANs) and AOX (Adsorbable Organic Halides). Several compounds investigated formed NDMA in greater amounts than DMA, revealing the importance of structural characteristics of tertiary amines for NDMA formation. Among these compounds, the pharmaceutical ranitidine showed the highest molar conversion to NDMA. The pH and dissolved oxygen content of the solution were found to play a major role for the formation of NDMA from ranitidine. NDMA was formed in higher amounts at pH around pH 8 and a lower concentration of dissolved oxygen dramatically decreased NDMA yields. These findings seem to indicate that dichloramine (NHCl(2)) is not the major oxidant involved in the formation of NDMA from ranitidine, results in contradiction with the reaction mechanisms proposed in the literature. Dissolved oxygen was also found to influence the formation of other oxygen-containing DBPs (i.e. trichloronitromethane and haloketones). The results of this study identify several anthropogenic precursors of NDMA, indicating that chloramination of waters impacted by these tertiary amines could lead to the formation of significant amounts of NDMA and other non-regulated DBPs of potential health concern (e

  17. Survival of cool and warm freshwater fish following chloramine-T exposure

    Science.gov (United States)

    Gaikowski, M.P.; Larson, W.J.; Gingerich, W.H.

    2008-01-01

    Chloramine-T is presently available in the USA to control mortalities associated with bacterial gill disease or external columnaris only through an Investigational New Animal Drug Permit authorized by the US Food and Drug Administration (FDA). Its US approval hinges on FDA's acceptance of several key data, including those describing animal safety. Chloramine-T is presently applied in US aquaculture, by permit only, once daily on consecutive or alternate days for 1??h at 10 to 20??mg/L to control mortalities associated with bacterial gill disease or external columnaris. Our objective was to determine the safety of chloramine-T bath exposures at multiples of the proposed maximum treatment concentration (i.e., 0, 20, 60, 100, and 200??mg/L) administered on four consecutive days at 20????C to lake sturgeon Acipenser fulvescens, northern pike Esox lucius, and walleye Sander vitreum, or at 27????C to channel catfish Ictalurus punctatus, and largemouth bass Micropterus salmoides. All fish were tested as five to eight week old fry except for walleye and channel catfish which were tested as both fry and fingerling (fingerlings were at least four weeks older than the fry tested). Walleye and channel catfish were selected to evaluate the effects of life stage (fry vs. fingerling), temperature (walleye - 15, 20, or 25????C; channel catfish - 22, 27, or 32????C), exposure duration (60 vs. 180??min), and water chemistry (walleye only - reconstituted soft water vs. well water). Except for channel catfish fry, survival was significantly reduced only when fish were treated at 100 or 200??mg/L. Channel catfish fry survival was significantly reduced when exposed at 60??mg/L for 180??min at 27????C. Based on our mortality data, chloramine-T administered once daily for 60??min on four consecutive days at concentrations of up to 20??mg/L is not likely to adversely affect survival of cool or warmwater fish cultured in freshwater. Crown Copyright ?? 2007.

  18. 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.

  19. Chloramination of nitrogenous contaminants (pharmaceuticals and pesticides): NDMA and halogenated DBPs formation

    KAUST Repository

    Le Roux, Julien

    2011-05-01

    Disinfection with chloramines is often used to reduce the production of regulated disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). However, chloramination can lead to the formation of N-nitrosamines, including N-nitrosodimethylamine (NDMA), a probable human carcinogen. Previous research used dimethylamine (DMA) as a model precursor of NDMA, but certain widely used tertiary dimethylamines (e.g. the pharmaceutical ranitidine) show much higher conversion rates to NDMA than DMA. This study investigates the NDMA formation potential of several tertiary amines including pharmaceuticals and herbicides. The reactivity of these molecules with monochloramine (NH2Cl) is studied through the formation of NDMA, and other halogenated DBPs such as haloacetonitriles (HANs) and AOX (Adsorbable Organic Halides). Several compounds investigated formed NDMA in greater amounts than DMA, revealing the importance of structural characteristics of tertiary amines for NDMA formation. Among these compounds, the pharmaceutical ranitidine showed the highest molar conversion to NDMA. The pH and dissolved oxygen content of the solution were found to play a major role for the formation of NDMA from ranitidine. NDMA was formed in higher amounts at pH around pH 8 and a lower concentration of dissolved oxygen dramatically decreased NDMA yields. These findings seem to indicate that dichloramine (NHCl2) is not the major oxidant involved in the formation of NDMA from ranitidine, results in contradiction with the reaction mechanisms proposed in the literature. Dissolved oxygen was also found to influence the formation of other oxygen-containing DBPs (i.e. trichloronitromethane and haloketones). The results of this study identify several anthropogenic precursors of NDMA, indicating that chloramination of waters impacted by these tertiary amines could lead to the formation of significant amounts of NDMA and other non-regulated DBPs of potential health concern (e

  20. Using chloramine as a coagulant aid in enhancing coagulation of Yellow River water in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Considering that contaminated raw water mostly contains high Ammonia-N and a majority of water treatment plants use prechlorination process in China, efficiency of chloramines as a coagulant aid in enhancing coagulation was investigated by Jar stirring and pilot-scale tests, using Yellow River water containing high concentration of natural organic matters (NOM) and bromide in winter. The jar tests results showed that, compared with no preoxidation, preformed chloramine apparently decreased the turbidity of settled and filtered water with low dosage (2.0 mg/L), and the aid-coagulation efficiency was further enhanced with the increase of chlorine (Cl2) to Ammonia-N (N) ratio. Pilot-scale studies indicated that, in comparison to the case without preoxidation, the turbidity removal efficiency of flotation and filtration effluent water was significantly improved, the particle counts of filtered water were decreased 63.4%, the average rate of filter head loss was reduced 18.2%, and filter run time was prolonged 15.7%. Therefore, chloramine preoxidation may substantially enhance the particle separation efficiency.

  1. Formation and cytotoxicity of a new disinfection by-product (DBP) phenazine by chloramination of water containing diphenylamine

    Institute of Scientific and Technical Information of China (English)

    Wenjun Zhou; Linjie Lou; Lifang Zhu; Zhimin Li; Lizhong Zhu

    2012-01-01

    Disinfection by-products (DBPs) in drinking water have caused worldwide concern due to their potential earcinogenic effects.The formation of phenazine from diphenylamine (DPhA) chloramination was studied and its cytotoxicities for two human cancer cells were also investigated.Phenazine was detected synchronously with the consumption of DPhA by chloramination,which further confirmed that the new DBP phenazine can be produced along with N-nitrosodiphenylamine (NDPhA) from DPhA chloramination.The formation of phenazine had a maximum molar yield with solution pH increasing from 5.0 to 9.0,with phernazine as the main product for DPhA chloramination at lower pH,but higher pH favored the formation of NDPhA.Thus,solution pH is the key factor in controlling the formation of phenazine and NDPhA.Both the initial DPhA and chloramine concentrations did not show a significant effect on the molar yields of phenazine,although increasing the chloramine concentration could speed up the reacdon rate of DPhA with chloramines.The cytotoxicity assays showed that phenazine had significant cell-specific toxicity towards T24 (bladder cancer cell lines) and HepG2 (hepatic tumor cell lines) cells with IC50 values of 0.50 and 2.04 mmol/L,respectively,and T24 ceils being more sensitive to phenazine than HepG2 ceils.The IC50 values of phenazine,DPhA,and NDPhA for T24 cells were of the same order of magnitude and the cytotoxicity of phenazine for T24 cells was slightly lower than that of NDPhA (IC50,0.16 mmol/L),suggesting that phenazine in drinking water may have an adverse effect on human health.

  2. Acid-base and ionic fluxes in rainbow trout (Oncorhynchus mykiss) during exposure to chloramine-T

    Energy Technology Data Exchange (ETDEWEB)

    Powell, M.D.; Perry, S.F. [Department of Biology, University of Ottawa, 30 Marie Curie Ottawa, Ontario, K1N 6N5 (Canada)

    1998-09-01

    The effects of chloramine-T and its degradation products, sodium hypochlorite (NaOCl) and para-toluenesulphonamide (pTSA), on whole body acid-base and branchial and renal ion (Na{sup +}and Cl{sup -}) fluxes were examined in rainbow trout (Oncorhynchus mykiss). Exposure to chloramine-T (3.5 h, 18 mg l{sup -1}) resulted in increases in plasma total CO{sub 2} but no coincident rise in P{sub a}CO{sub 2} or reduction in blood pH. Exposure of fish to 2, 9 or 18 mg l{sup -1} chloramine-T (3.5 h duration) resulted in a reduction in net acid uptake suggesting the development of a metabolic alkalosis. Exposure to the chloramine-T breakdown product pTSA (dissolved in DMSO) resulted in increased net acid uptake (decreased acid excretion) suggesting a metabolic acidosis. Whole body ion fluxes demonstrated increases in the losses of both Na{sup +}and Cl{sup -} with chloramine-T, NaOCl and pTSA. However, the effect of DMSO alone could not be isolated. Confirmatory studies using fish in which the urinary bladder (to allow collection of urine) and dorsal aorta (to allow injection of [{sup 14}C]polyethylene glycol 4000 ([{sup 14}C]PEG), an extracellular fluid marker) were catheterised, revealed that changes in whole body ion fluxes during chloramine-T exposure could not be explained by increased renal efflux through urine flow, glomerular filtration or renal clearance. Branchial effluxes of [{sup 14}C]PEG were not significantly affected by chloramine-T exposure suggesting that the changes in whole body ionic fluxes were caused by transcellular rather than paracellular processes. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. [Genotoxicity of drinking water during chlorine and chloramine disinfection and the influence of disinfection conditions using the umu-test].

    Science.gov (United States)

    Liu, Qing; Zhang, Li-Ping; Liu, Wen-Jun; Nie, Xue-Biao; Zhang, Su-Xia; Zhang, Shun

    2010-01-01

    In this study, the effects of disinfectant dosage, reaction time and the ratio of Cl2 to N of disinfectant on genotoxicity of effluent of ozone-biological activated carbon (O3-BAC) during chlorine or chloramine disinfection were investigated using umu-test. It was found that, the genotoxicity of effluent of O3-BAC before disinfection ranged from 20-70 ng/L, and it increased after disinfection by chlorine or chloramines. With the same reaction time(24 h), genotoxicity after chlorination (40-95 ng/L) was higher than that after chloramination (20-40 ng/L) under same initial dosage. For chlorination, with initial dosage increasing from 0 mg/L to 10 mg/L, genotoxicity increased firstly, and got the maximum value at about 0.5-1 mg/L dosage, then decreased and got the minimum value at about 3-5 mg/L dosage, and finally increased again. For chloramination, genotoxicity didn't change that much. With the dosage of 3 mg/L and reaction time increasing from 0 h to 72 h, no matter for chlorine or chloramines disinfection, genotoxicity of effluent of O3-BAC both increased firstly, and got the maximum value at about 2 h, then decreased and got the minimum value at about 18 h, and finally increased again, and genotoxicity after chlorine disinfection (83-120 ng/L) was higher than that after chloramines disinfection (20-62 ng/L) under same reaction time. Further more, effects of the different ratios of Cl2 to N of disinfectant on genotoxicity of effluent of O3-BAC were also studied. Results of this study demonstrate that under test conditions, chloramine disinfection is safer than chlorine disinfection in the aspect of genotoxicity for drinking water, and the changes of genotoxicity are different from those of total HAAs.

  4. Ammonia-oxidizing bacteria in a chloraminated distribution system: seasonal occurrence, distribution and disinfection resistance.

    Science.gov (United States)

    Wolfe, R L; Lieu, N I; Izaguirre, G; Means, E G

    1990-02-01

    Nitrification in chloraminated drinking water can have a number of adverse effects on water quality, including a loss of total chlorine and ammonia-N and an increase in the concentration of heterotrophic plate count bacteria and nitrite. To understand how nitrification develops, a study was conducted to examine the factors that influence the occurrence of ammonia-oxidizing bacteria (AOB) in a chloraminated distribution system. Samples were collected over an 18-month period from a raw-water source, a conventional treatment plant effluent, and two covered, finished-water reservoirs that previously experienced nitrification episodes. Sediment and biofilm samples were collected from the interior wall surfaces of two finished-water pipelines and one of the covered reservoirs. The AOB were enumerated by a most-probable-number technique, and isolates were isolated and identified. The resistance of naturally occurring AOB to chloramines and free chlorine was also examined. The results of the monitoring program indicated that the levels of AOB, identified as members of the genus Nitrosomonas, were seasonally dependent in both source and finished waters, with the highest levels observed in the warm summer months. The concentrations of AOB in the two reservoirs, both of which have floating covers made of synthetic rubber (Hypalon; E.I. du Pont de Nemours & Co., Inc., Wilmington, Del.), had most probable numbers that ranged from less than 0.2 to greater than 300/ml and correlated significantly with temperature and levels of heterotrophic plate count bacteria. No AOB were detected in the chloraminated reservoirs when the water temperature was below 16 to 18 degrees C. The study indicated that nitrifiers occur throughout the chloraminated distribution system. Higher concentrations of AOB were found in the reservoir and pipe sediment materials than in the pipe biofilm samples. The AOB were approximately 13 times more resistant to monochloramine than to free chlorine. After 33 min

  5. The role of aromatic precursors in the formation of haloacetamides by chloramination of dissolved organic matter.

    Science.gov (United States)

    Le Roux, Julien; Nihemaiti, Maolida; Croué, Jean-Philippe

    2016-01-01

    Water treatment utilities are diversifying their water sources and often rely on waters enriched in nitrogen-containing compounds (e.g., ammonia, organic nitrogen such as amino acids). The disinfection of waters exhibiting high levels of nitrogen has been associated with the formation of nitrogenous disinfection byproducts (N-DBPs) such as haloacetonitriles (HANs) and haloacetamides (HAcAms). While the potential precursors of HANs have been extensively studied, only few investigations are available regarding the nature of HAcAm precursors. Previous research has suggested that HAcAms are hydrolysis products of HANs. Nevertheless, it has been recently suggested that HAcAms can be formed independently, especially during chloramination of humic substances. When used as a disinfectant, monochloramine can also be a source of nitrogen for N-DBPs. This study investigated the role of aromatic organic matter in the formation of N-DBPs (HAcAms and HANs) upon chloramination. Formation kinetics were performed from various fractions of organic matter isolated from surface waters or treated wastewater effluents. Experiments were conducted with (15)N-labeled monochloramine ((15)NH2Cl) to trace the origin of nitrogen. N-DBP formation showed a two-step profile: (1) a rapid formation following second-order reaction kinetics and incorporating nitrogen atom originating from the organic matrix (e.g., amine groups); and (2) a slower and linear increase correlated with exposure to chloramines, incorporating inorganic nitrogen ((15)N) from (15)NH2Cl into aromatic moieties. Organic matter isolates showing high aromatic character (i.e., high SUVA) exhibited high reactivity characterized by a major incorporation of (15)N in N-DBPs. A significantly lower incorporation was observed for low-aromatic-content organic matter. (15)N-DCAcAm and (15)N-DCAN formations exhibited a linear correlation, suggesting a similar behavior of (15)N incorporation as SUVA increases. Chloramination of aromatic model

  6. The role of aromatic precursors in the formation of haloacetamides by chloramination of dissolved organic matter

    KAUST Repository

    Le Roux, Julien

    2015-10-21

    Water treatment utilities are diversifying their water sources and often rely on waters enriched in nitrogen-containing compounds (e.g., ammonia, organic nitrogen such as amino acids). The disinfection of waters exhibiting high levels of nitrogen has been associated with the formation of nitrogenous disinfection byproducts (N-DBPs) such as haloacetonitriles (HANs) and haloacetamides (HAcAms). While the potential precursors of HANs have been extensively studied, only few investigations are available regarding the nature of HAcAm precursors. Previous research has suggested that HAcAms are hydrolysis products of HANs. Nevertheless, it has been recently suggested that HAcAms can be formed independently, especially during chloramination of humic substances. When used as a disinfectant, monochloramine can also be a source of nitrogen for N-DBPs. This study investigated the role of aromatic organic matter in the formation of N-DBPs (HAcAms and HANs) upon chloramination. Formation kinetics were performed from various fractions of organic matter isolated from surface waters or treated wastewater effluents. Experiments were conducted with 15N-labeled monochloramine (15NH2Cl) to trace the origin of nitrogen. N-DBP formation showed a two-step profile: (1) a rapid formation following second-order reaction kinetics and incorporating nitrogen atom originating from the organic matrix (e.g., amine groups); and (2) a slower and linear increase correlated with exposure to chloramines, incorporating inorganic nitrogen (15N) from 15NH2Cl into aromatic moieties. Organic matter isolates showing high aromatic character (i.e., high SUVA) exhibited high reactivity characterized by a major incorporation of 15N in N-DBPs. A significantly lower incorporation was observed for low-aromatic-content organic matter. 15N-DCAcAm and 15N-DCAN formations exhibited a linear correlation, suggesting a similar behavior of 15N incorporation as SUVA increases. Chloramination of aromatic model compounds (i

  7. Real-time ArcGIS and heterotrophic plate count based chloramine disinfectant control in water distribution system.

    Science.gov (United States)

    Bai, Xiaohui; Zhi, Xinghua; Zhu, Huifeng; Meng, Mingqun; Zhang, Mingde

    2015-01-01

    This study investigates the effect of chloramine residual on bacteria growth and regrowth and the relationship between heterotrophic plate counts (HPCs) and the concentration of chloramine residual in the Shanghai drinking water distribution system (DWDS). In this study, models to control HPCs in the water distribution system and consumer taps are also developed. Real-time ArcGIS was applied to show the distribution and changed results of the chloramine residual concentration in the pipe system by using these models. Residual regression analysis was used to get a reasonable range of the threshold values that allows the chloramine residual to efficiently inhibit bacteria growth in the Shanghai DWDS; the threshold values should be between 0.45 and 0.5 mg/L in pipe water and 0.2 and 0.25 mg/L in tap water. The low residual chloramine value (0.05 mg/L) of the Chinese drinking water quality standard may pose a potential health risk for microorganisms that should be improved. Disinfection by-products (DBPs) were detected, but no health risk was identified.

  8. Photolysis of inorganic chloramines and efficiency of trichloramine abatement by UV treatment of swimming pool water.

    Science.gov (United States)

    Soltermann, Fabian; Widler, Tobias; Canonica, Silvio; von Gunten, Urs

    2014-06-01

    Trichloramine, one of the three inorganic chloramines (mono-, di- and trichloramine), is a problematic disinfection by-product in recreational pool water since it causes skin and eye irritations as well as irritations of the respiratory tract. The most commonly used chloramine mitigation strategy in pool water is UV treatment. Experiments with membrane inlet mass spectrometry (MIMS) confirmed that inorganic chloramines are effectively degraded by UV irradiation with low-pressure (LP) and medium-pressure (MP) mercury lamps (apparent quantum yields (QY): NH2Cl = 0.50 (LP) and 0.31 (MP) mol einstein(-1), NHCl2: 1.06 (LP) and 0.85 (MP) mol einstein(-1)). Trichloramine showed the fastest depletion with a quantum yield slightly above 2 mol einstein(-1) in purified (LP and MP) and pool water (MP). This high quantum yield can partly be explained by reactions involving OH radicals (purified water) and the reaction of trichloramine with moieties formed during UV irradiation of pool water. The presence of free chlorine affects trichloramine degradation (QY: ∼1.5 mol einstein(-1)) since it scavenges OH radicals and competes with trichloramine for reactive species (e.g. organic amines). Measurements in a pool facility revealed that the installed UV reactors degraded trichloramine by 40-50% as expected from laboratory experiments. However, trichloramine reduction in the pools was less pronounced than in the UV reactors. Model calculations combining pool hydraulics with formation/abatement of trichloramine showed that there was a fast trichloramine formation in the pool from the residual chlorine and nitrogenous precursors. The main factors influencing trichloramine concentrations in pool water are the free chlorine concentration and the UV treatment in combination with the recirculation rate through the water treatment system.

  9. Determinants of disinfectant pretreatment efficacy for nitrosamine control in chloraminated drinking water.

    Science.gov (United States)

    McCurry, Daniel L; Krasner, Stuart W; von Gunten, Urs; Mitch, William A

    2015-11-01

    Utilities using chloramines need strategies to mitigate nitrosamine formation to meet potential future nitrosamine regulations. The ability to reduce NDMA formation under typical post-chloramination conditions of pretreatment with ultraviolet light from a low pressure mercury lamp (LPUV), free chlorine (HOCl), ozone (O3), and UV light from a medium pressure mercury lamp (MPUV) were compared at exposures relevant to drinking water treatment. The order of efficacy after application to waters impacted by upstream wastewater discharges was O3 > HOCl ≈ MPUV > LPUV. NDMA precursor abatement generally did not correlate well between oxidants, and waters exhibited different behaviors with respect to pH and temperature, suggesting a variety of source-dependent NDMA precursors. For wastewater-impacted waters, the observed pH dependence for precursor abatement suggested the important role of secondary or tertiary amine precursors. Although hydroxyl radicals did not appear to be important for NDMA precursor abatement during O3 or MPUV pretreatment, the efficacy of MPUV correlated strongly with dissolved organic carbon concentration (p = 0.01), suggesting alternative indirect photochemical pathways. The temperature dependences during pre- and post-disinfection indicated that NDMA formation is likely to increase during warm seasons for O3 pretreatment, decrease for HOCl pretreatment, and remain unchanged for MPUV treatment, although seasonal changes in source water quality may counteract the temperature effects. For two waters impacted by relatively high polyDADMAC coagulant doses, pretreatment with HOCl, O3, and MPUV increased NDMA formation during post-chloramination. For O3 pretreatment, hydroxyl radicals likely led to precursor formation from the polymer in the latter tests. MPUV treatment of polymer-impacted water increased subsequent NDMA formation through an indirect photochemical process. Many factors may mitigate the importance of this increased NDMA formation

  10. Comparison of chlorine and chloramine in the release of mercury from dental amalgam.

    Science.gov (United States)

    Stone, Mark E; Scott, John W; Schultz, Stephen T; Berry, Denise L; Wilcoxon, Monte; Piwoni, Marv; Panno, Brent; Bordson, Gary

    2009-01-01

    The purpose of this project was to compare the ability of chlorine (HOCl/OCl(-)) and monochloramine (NH(2)Cl) to mobilize mercury from dental amalgam. Two types of amalgam were used in this investigation: laboratory-prepared amalgam and samples obtained from dental-unit wastewater. For disinfectant exposure simulations, 0.5 g of either the laboratory-generated or clinically obtained amalgam waste was added to 250 mL amber bottles. The amalgam samples were agitated by end-over-end rotation at 30 rpm in the presence of 1 mg/L chlorine, 10 mg/L chlorine, 1 mg/L monochloramine, 10 mg/L monochloramine, or deionized water for intervals of 0 h, 2 h, 4 h, 8 h, and 24 h for the clinically obtained amalgam waste samples and 4 h and 24 h for the laboratory-prepared samples. Chlorine and monochloramine concentrations were measured with a spectrophotometer. Samples were filtered through a 0.45 microm membrane filter and analyzed for mercury with USEPA standard method 245.7. When the two sample types were combined, the mean mercury level in the 1 mg/L chlorine group was 0.020 mg/L (n=25, SD=0.008). The 10 mg/L chlorine group had a mean mercury concentration of 0.59 mg/L (n=25, SD=1.06). The 1 mg/L chloramine group had a mean mercury level of 0.023 mg/L (n=25, SD=0.010). The 10 mg/L chloramine group had a mean mercury level of 0.024 mg/L (n=25, SD=0.011). Independent samples t-tests showed that there was a significant difference between the natural log mercury measurements of 10 mg/L chlorine compared to those of 1 mg/L and 10 mg/L chloramine. Changing from chlorine to chloramine disinfection at water treatment plants would not be expected to produce substantial increases in dissolved mercury levels in dental-unit wastewater.

  11. Correlation between SUVA and DBP formation during chlorination and chloramination of NOM fractions from different sources.

    Science.gov (United States)

    Hua, Guanghui; Reckhow, David A; Abusallout, Ibrahim

    2015-07-01

    Natural organic matter (NOM) is the major precursor to the formation of disinfection byproducts (DBPs) during drinking water treatment. Specific ultraviolet absorbance (SUVA) is a widely used surrogate parameter to characterize NOM and predict its DBP formation potential. The objective of this study was to determine the relationships between SUVA and different classes of DBPs formed by NOM fractions from different sources. Three natural waters with a wide SUVA range were fractionated into differing hydrophobicity and molecular weight groups using XAD-4 and XAD-8 resins and ultrafiltration membranes. Each NOM fraction was treated with chlorine and monochloramine under controlled laboratory conditions. Different classes of DBPs showed different relationships with SUVA. SUVA correlated strongly with trihaloacetic acids (THAAs) and unknown total organic halogen (UTOX) yields whereas weak correlations were observed between SUVA and trihalomethane (THM) and dihaloacetic acid (DHAA) yields during chlorination. These results reinforce the hypothesis that DHAAs and THAAs form through different precursors and reaction pathways. Strong correlation between SUVA and UTOX was also observed during chloramination. However, no significant relationship was observed between SUVA and chloramination THMs and DHAAs. Overall, SUVA is a good indicator for the formation of unknown DBPs. This indicates that UV absorbing compounds and aromatic carbon within NOM are the primary sources of precursors for unknown DBPs.

  12. 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.

  13. Thermodynamics of Micellization of Nonionic Surfactant Tween-40 in Presence of Additive Chloramine-T Using Clouding Phenomenon

    Directory of Open Access Journals (Sweden)

    A. A. Patil

    2010-01-01

    Full Text Available The phenomenon of solubilization of nonionic surfactant Tween-40 has been studied through the influence of additive chloramine-T in aqueous medium by measuring the cloud points (CP of the pure surfactant and with chloramine-T. The CP of pure surfactant was found to be increased with increasing concentration of Tween-40. The CP of mixed system shows increasing trends with increased chloramine-T. This is mainly due to increased micelle concentrations. The influence of chloramine-T on the cloud point of Tween-40 is a clear indication that the phenomenon of clouding is associated with the different micelles coalescing. Considering cloud point as threshold temperature of the solubility, the thermodynamic parameters of clouding process (ΔG0cl, ΔH0cl and ΔS0cl have been evaluated using “Phase Separation Model”. The phase separation results from micelle-micelle interaction. It was found that the overall clouding process was exothermic and ΔH0cl > TΔS0cl indicating that the process of clouding was guided by both enthalpy and entropy. This work supports the conjecture that the clouding is critical phenomenon rather than the growth of micelles. Findings of the present work supports to made the probable evidence of electrolyte-surfactant interactions in aqueous medium.

  14. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration...

  15. Catalyst-Free Imidation of Allyl Sulfides with Chloramine-T and Subsequent [2,3]-Sigmatropic Rearrangement

    Institute of Scientific and Technical Information of China (English)

    江玉波; 莫凡洋; 邱迪; 匡春香; 张艳; 王剑波

    2012-01-01

    A facile synthesis of various allyl sulfonamides based on imidation of allyl sulfides with chloramine-T and sub- sequent [2,3]-sigmatropic rearrangement has been achieved without metal catalysts. The reaction completes smoothly within 10 min, providing excellent yields in environment friendly solvent of alcohol. Functional groups such as bromine, hydroxyl, protected amido and aldehyde are tolerant under this condition.

  16. Inhalation exposure to chloramine T induces DNA damage and inflammation in lung of Sprague-Dawley rats.

    Science.gov (United States)

    Shim, Ilseob; Seo, Gyun-Baek; Oh, Eunha; Lee, Mimi; Kwon, Jung-Taek; Sul, Donggeun; Lee, Byung-Woo; Yoon, Byung-Il; Kim, Pilje; Choi, Kyunghee; Kim, Hyun-Mi

    2013-01-01

    Chloramine T has been widely used as a disinfectant in many areas such as kitchens, laboratories and hospitals. It has been also used as a biocide in air fresheners and deodorants which are consumer products; however, little is known about its toxic effects by inhalation route. This study was performed to identify the subacute inhalation toxicity of chloramine T under whole-body inhalation exposure conditions. Male and female groups of rats were exposed to chloramine T at concentrations of 0.2, 0.9 and 4.0 mg/m³ for 6 hr/day, 5 days/week during 4 weeks. After 28-day repeated inhalation of chloramine T, there were dose-dependently significant DNA damage in the rat tissues evaluated and inflammation was histopathologically noted around the terminal airways of the lung in both genders. As a result of the expression of three types of antioxidant enzymes (SOD-2, GPx-1, PRX-1) in rat's lung after exposure, there was no significant change of all antioxidant enzymes in the male and female rats. The results showed that no observed adverse effect level (NOAEL) was 0.2 mg/m³ in male rats and 0.9 mg/m³ in female rats under the present experimental condition.

  17. Microbial community dynamics of an urban drinking water distribution system subjected to phases of chloramination and chlorination treatments.

    Science.gov (United States)

    Hwang, Chiachi; Ling, Fangqiong; Andersen, Gary L; LeChevallier, Mark W; Liu, Wen-Tso

    2012-11-01

    Water utilities in parts of the U.S. control microbial regrowth in drinking water distribution systems (DWDS) by alternating postdisinfection methods between chlorination and chloramination. To examine how this strategy influences drinking water microbial communities, an urban DWDS (population ≅ 40,000) with groundwater as the source water was studied for approximately 2 years. Water samples were collected at five locations in the network at different seasons and analyzed for their chemical and physical characteristics and for their microbial community composition and structure by examining the 16S rRNA gene via terminal restriction fragment length polymorphism and DNA pyrosequencing technology. Nonmetric multidimension scaling and canonical correspondence analysis of microbial community profiles could explain >57% of the variation. Clustering of samples based on disinfection types (free chlorine versus combined chlorine) and sampling time was observed to correlate to the shifts in microbial communities. Sampling location and water age (analysis revealed that among major core populations, Cyanobacteria, Methylobacteriaceae, Sphingomonadaceae, and Xanthomonadaceae were more abundant in chlorinated water, and Methylophilaceae, Methylococcaceae, and Pseudomonadaceae were more abundant in chloraminated water. No correlation was observed with minor populations that were detected frequently (water and survived through the treatment process. Transient microbial populations including Flavobacteriaceae and Clostridiaceae were also observed. Overall, reversible shifts in microbial communities were especially pronounced with chloramination, suggesting stronger selection of microbial populations from chloramines than chlorine.

  18. A Long-Term Study of the Microbial Community Structure in a Simulated Chloraminated Drinking Water Distribution System

    Science.gov (United States)

    Free chlorine is used as the primary disinfectant in most drinking water distribution systems(DWDS). However, chlorine disinfection promotes the formation of disinfectant by-products (DBPs)and as a result, many US water treatment facilities use chloramination to ensure regulatory...

  19. Bilirubin scavenges chloramines and inhibits myeloperoxidase-induced protein/lipid oxidation in physiologically relevant hyperbilirubinemic serum.

    Science.gov (United States)

    Boon, A C; Hawkins, C L; Coombes, J S; Wagner, K H; Bulmer, A C

    2015-09-01

    Hypochlorous acid (HOCl), an oxidant produced by myeloperoxidase (MPO), induces protein and lipid oxidation, which is implicated in the pathogenesis of atherosclerosis. Individuals with mildly elevated bilirubin concentrations (i.e., Gilbert syndrome; GS) are protected from atherosclerosis, cardiovascular disease, and related mortality. We aimed to investigate whether exogenous/endogenous unconjugated bilirubin (UCB), at physiological concentrations, can protect proteins/lipids from oxidation induced by reagent and enzymatically generated HOCl. Serum/plasma samples supplemented with exogenous UCB (≤250µM) were assessed for their susceptibility to HOCl and MPO/H2O2/Cl(-) oxidation, by measuring chloramine, protein carbonyl, and malondialdehyde (MDA) formation. Serum/plasma samples from hyperbilirubinemic Gunn rats and humans with GS were also exposed to MPO/H2O2/Cl(-) to: (1) validate in vitro data and (2) determine the relevance of endogenously elevated UCB in preventing protein and lipid oxidation. Exogenous UCB dose-dependently (P<0.05) inhibited HOCl and MPO/H2O2/Cl(-)-induced chloramine formation. Albumin-bound UCB efficiently and specifically (3.9-125µM; P<0.05) scavenged taurine, glycine, and N-α-acetyllysine chloramines. These results were translated into Gunn rat and GS serum/plasma, which showed significantly (P<0.01) reduced chloramine formation after MPO-induced oxidation. Protein carbonyl and MDA formation was also reduced after MPO oxidation in plasma supplemented with UCB (P<0.05; 25 and 50µM, respectively). Significant inhibition of protein and lipid oxidation was demonstrated within the physiological range of UCB, providing a hypothetical link to protection from atherosclerosis in hyperbilirubinemic individuals. These data demonstrate a novel and physiologically relevant mechanism whereby UCB could inhibit protein and lipid modification by quenching chloramines induced by MPO-induced HOCl.

  20. Comparison of chlorination and chloramination in carbonaceous and nitrogenous disinfection byproduct formation potentials with prolonged contact time.

    Science.gov (United States)

    Sakai, Hiroshi; Tokuhara, Shunsuke; Murakami, Michio; Kosaka, Koji; Oguma, Kumiko; Takizawa, Satoshi

    2016-01-01

    Due to decreasing water demands in Japan, hydraulic retention times of water in piped supply systems has been extended, resulting in a longer contact time with disinfectants. However, the effects of extended contact time on the formation of various disinfection byproducts (DBPs), including carbonaceous DBPs such as trihalomethane (THM) and haloacetic acid (HAA), and nitrogenous DBPs such as nitrosodimethylamine (NDMA) and nitrosomorpholine (NMor), have not yet been investigated in detail. Herein, we compared the formation of these DBPs by chlorination and chloramination for five water samples collected from rivers and a dam in Japan, all of which represent municipal water supply sources. Water samples were treated by either filtration or a combination of coagulation and filtration. Treated samples were subjected to a DBP formation potential test by either chlorine or chloramine for contact times of 1 day or 4 days. Four THM species, nine HAA species, NDMA, and NMor were measured by GC-ECD or UPLC-MS/MS. Lifetime cancer risk was calculated based on the Integrated Risk Information System unit risk information. The experiment and analysis focused on (i) prolonged contact time from 1 day to 4 days, (ii) reduction efficiency by conventional treatment, (iii) correlations between DBP formation potentials and water quality parameters, and (iv) the contribution of each species to total risk. With an increased contact time from 1 day to 4 days, THM formation increased to 420% by chloramination. Coagulation-filtration treatment showed that brominated species in THMs are less likely to be reduced. With the highest unit risk among THM species, dibromochloromethane (DBCM) showed a high correlation with bromine, but not with organic matter parameters. NDMA contributed to lifetime cancer risk. The THM formation pathway should be revisited in terms of chloramination and bromine incorporation. It is also recommended to investigate nitrosamine formation potential by

  1. Draft genome sequence of two Shingopyxis sp. strains H107 and H115 isolated from a chloraminated drinking water distriburion system simulator

    Data.gov (United States)

    U.S. Environmental Protection Agency — Draft genome sequence of two Shingopyxis sp. strains H107 and H115 isolated from a chloraminated drinking water distriburion system simulator. This dataset is...

  2. Identification of tobacco-specific nitrosamines as disinfection byproducts in chloraminated water.

    Science.gov (United States)

    Wu, Minghuo; Qian, Yichao; Boyd, Jessica M; Leavey, Shannon; Hrudey, Steve E; Krasner, Stuart W; Li, Xing-Fang

    2014-01-01

    Tobacco-specific nitrosamines (TSNAs) exist in environmental waters; however, it is unknown whether TSNAs can be produced during water disinfection. Here we report on the investigation and evidence of TSNAs as a new class of disinfection byproducts (DBPs). Using five common TSNAs, including (methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as the targets, we first developed a solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method capable of rapidly determining these TSNAs at levels as low as 0.02 ng/L in treated water. Using this highly sensitive method, we investigated the occurrence and formation potential (FP) (precursor test conducted in the presence of chloramines) of TSNAs in treated water from two wastewater treatment plants (WWTPs) and seven drinking water treatment plants (DWTPs). NNAL was detected in the FP samples, but not in the samples before the FP test, confirming NNAL as a DBP. NNK was detected in the treated wastewater before the FP test, but its concentration increased significantly after chloramination in two of three tests. Thus, NNK could be a DBP and/or a contaminant in wastewater. Moreover, these TSNAs were detected in FP tests of wastewater-impacted DWTP plant influents in 9 of 11 samples. However, TSNAs were not detected at full-scale DWTPs, except for at one DWTP with high ammonia where breakpoint chlorination was not achieved. The concentration of the sum of five TSNAs (0.3 ng/L) was 100-fold lower than NDMA, suggesting that TSNAs have a minor contribution to total nitrosamines in water. We examined several factors in the treatment process and found that chlorine or ozone may destroy TSNA precursors and granular activated carbon (GAC) treatment may remove the precursors. Further research is warranted into the efficiency of these processes at different DWTPs using sources of varying water quality.

  3. 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.

  4. Catalytic Effect of Cetyltrimethylammonium Bromide on the Oxidation of Triethylene glycol by Chloramine-T in Acidic Medium

    Directory of Open Access Journals (Sweden)

    Vandana Sharma

    2008-01-01

    Full Text Available The kinetics and mechanism of cetyltrimethylammonium bromide catalyzed oxidation of triethylene glycol [2,2'-ethylene diqxybis(ethanol] by chloramine-T in acidic acid medium have been investigated. The reaction is first order dependence on chloramine-T and fractional order for triethylene glycol with excess concentration of other reactants. The catalytic effect due to cetyletrimethylammonium bromide has been studied. The small salt effect and increase in the reaction rate with increasing dielectric constant suggest the involvement of neutral molecule in the rate-determining step. The addition of p-toluene sulfonamide retards the reaction rate. The effect of chloride ion on the reaction also studied. The effect of temperature on the reaction has been investigated in the temperature range 313-333K and thermodynamic parameters were calculated from the Arrhenious plot. A tentative mechanism consistent with the experimental results has been proposed.

  5. Effects of ozone and ozone/peroxide pretreatments on disinfection byproduct formation during subsequent chlorination and chloramination.

    Science.gov (United States)

    Yang, Xin; Peng, Jinfeng; Chen, Baiyang; Guo, Wanhong; Liang, Yongmei; Liu, Wei; Liu, Lu

    2012-11-15

    Ozone (O3) and ozone/hydrogen peroxide (O3/H2O2) can be used in water treatment facilities to remove many organic micropollutants with taste, odor, and color implications. The effects of O3 and O3/H2O2 on the formation of disinfection byproducts (DBPs) in subsequent chlorination and chloramination processes, however, are not well determined. In this study, we compared the yields of a series of regulated and emerging DBPs during sequenced O3-Cl2, O3/H2O2-Cl2, O3-NH2Cl, and O3/H2O2-NH2Cl oxidation of 11 samples, each with different hydrophobicity, bromide concentration, soluble microbial products, and humic substances. For most water, pretreatment with O3 and O3/H2O2 increased the formation of chloral hydrate (CH), trichloronitromethane (TCNM) and haloketones (HKs) but lowered the yields of haloacetonitriles (HANs) during chlorination processes. Compared with O3 alone, O3/H2O2 in combination generated more CH and HKs during chlorination, and their extents of formation appeared to depend on the O3 doses. In terms of chloramination, both O3 and O3/H2O2 reduced THM, HAA, and HAN formation significantly without increasing CH, TCNM, or HKs. These results suggest that O3 or O3/H2O2 pretreatments may provide some benefits for the chloramination process in controlling regulated and emerging DBPs in waters without high bromide content.

  6. Modelling combined effect of chloramine and copper on ammonia-oxidizing microbial activity using a biostability approach.

    Science.gov (United States)

    Sarker, Dipok Chandra; Sathasivan, Arumugam; Rittmann, Bruce E

    2015-11-01

    Continuous and batch laboratory experiments were used to evaluate the combined effects of copper and chloramine on ammonia oxidizing microbes present in otherwise high nitrifying water samples. The experimental data were analyzed using a biostability concept and quantified with the biostable residual concentratrion (BRC) of monochloramine, or the concentration that prevents the onset of nitrification. In the batch experiments, copper dosing ≥0.25 mg-Cu L(-1) resulted in complete inhibition of nitrification, and a lower copper dosing (0.1 mg-Cu L(-1)) delayed nitrification. The BRC was systematically lowered with the addition of copper. For example, a free-ammonium concentration of 0.1 mg-N L(-1) had a BRC of 0.73 mg-Cl2 L(-1) with no Cu, but addition of 0.1 mg-Cu L(-1) lowered the BRC to 0.16 mg-Cl2 L(-1), while addition of 0.25 mg-Cu L(-1) eliminated the need to add chloramine (BRC = 0). A non-competitive inhibition model fit the experimental data well with a copper threshold of 0.044 mg-Cu L(-1) and can be used to estimate Cu doses needed to prevent nitrification based on the chloramine concentration. Full scale systems applications need further study.

  7. Occurrences of nitrosamines in chlorinated and chloraminated drinking water in three representative cities, China

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Qian; Wang, Donghong; Wang, Zijian, E-mail: wangzj@rcees.ac.cn

    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. Highlights: Black-Right-Pointing-Pointer Nitrosamines in disinfected drinking water in three Chinese cities were investigated. Black-Right-Pointing-Pointer Some nitrosamines could be detected in raw water. Black-Right-Pointing-Pointer Advanced treatment affects nitrosamine levels both positively and negatively. Black-Right-Pointing-Pointer Organic matters

  8. The effect of inorganic precursors on disinfection byproduct formation during UV-chlorine/chloramine drinking water treatment.

    Science.gov (United States)

    Lyon, Bonnie A; Dotson, Aaron D; Linden, Karl G; Weinberg, Howard S

    2012-10-01

    Ultraviolet (UV) disinfection is being increasingly used in drinking water treatment. It is important to understand how its application to different types of water may influence finished water quality, particularly as anthropogenic activity continues to impact the quality of source waters. The objective of this study was to evaluate the effect of inorganic precursors on the formation of regulated and unregulated disinfection byproducts (DBPs) during UV irradiation of surface waters when combined with chlorination or chloramination. Samples were collected from three drinking water utilities supplied by source waters with varying organic and inorganic precursor content. The filtered samples were treated in the laboratory with a range of UV doses delivered from low pressure (LP, UV output at 253.7 nm) and medium pressure (MP, polychromatic UV output 200-400 nm) mercury lamps followed by chlorination or chloramination, in the presence and absence of additional bromide and nitrate. The regulated trihalomethanes and haloacetic acids were not affected by UV pretreatment at disinfection doses (40-186 mJ/cm²). With higher doses (1000 mJ/cm²), trihalomethane formation was increased 30-40%. While most effects on DBPs were only observed with doses much higher than typically used for UV disinfection, there were some effects on unregulated DBPs at lower doses. In nitrate-spiked samples (1-10 mg N/L), chloropicrin formation doubled and increased three- to six-fold with 40 mJ/cm² MP UV followed by chloramination and chlorination, respectively. Bromopicrin formation was increased in samples containing bromide (0.5-1 mg/L) and nitrate (1-10 mg N/L) when pretreated with LP or MP UV (30-60% with 40 mJ/cm² LP UV and four- to ten-fold increase with 40 mJ/cm² MP UV, after subsequent chlorination). The formation of cyanogen chloride doubled and increased three-fold with MP UV doses of 186 and 1000 mJ/cm², respectively, when followed by chloramination in nitrate-spiked samples but

  9. Formation of nitrogenous disinfection by-products in 10 chlorinated and chloraminated drinking water supply systems.

    Science.gov (United States)

    Liew, Deborah; Linge, Kathryn L; Joll, Cynthia A

    2016-09-01

    The presence of nitrogenous disinfection by-products (N-DBPs) in drinking water supplies is a public health concern, particularly since some N-DBPs have been reported to be more toxic than the regulated trihalomethanes and haloacetic acids. In this paper, a comprehensive evaluation of the presence of N-DBPs in 10 drinking water supply systems in Western Australia is presented. A suite of 28 N-DBPs, including N-nitrosamines, haloacetonitriles (HANs), haloacetamides (HAAms) and halonitromethanes (HNMs), were measured and evaluated for relationships with bulk parameters in the waters before disinfection. A number of N-DBPs were frequently detected in disinfected waters, although at generally low concentrations (water, N-DBP concentrations were significantly correlated with dissolved organic carbon (DOC) and ammonia, and these, in addition to high bromide in one of the waters, led to elevated concentrations of brominated HANs (26.6 μg/L of dibromoacetonitrile). There were significant differences in the occurrence of all classes of N-DBPs between chlorinated and chloraminated waters, except for HNMs, which were detected at relatively low concentrations in both water types. Trends observed in one large distribution system suggest that N-DBPs can continue to form or degrade within distribution systems, and redosing of disinfectant may cause further by-product formation.

  10. Preparation and characterization of an antibacterial ultrafiltration membrane with N-chloramine functional groups.

    Science.gov (United States)

    Hou, Shuhua; Dong, Xue; Zhu, Jianhua; Zheng, Jifu; Bi, Weihui; Li, Shenghai; Zhang, Suobo

    2017-06-15

    In this study, a cardo poly(aryl ether ketone) ultrafiltration membrane containing an N-chloramine functional group (PEK-N-Cl membrane) was easily obtained via exposure of a cardo poly(aryl ether ketone) ultrafiltration membrane (PEK-NH membrane) to dilute sodium hypochlorite solution. The chlorination process did not harm membrane performance. In addition, the PEK-N-Cl membrane was stable in both air and water. The PEK-N-Cl membrane exhibited excellent antimicrobial properties against both Gram-negative and Gram-positive bacteria (i.e. E. coli and Bacillus subtilis, respectively). The PEK-N-Cl membrane provided 94.2% and 100% reduction of E. coli and Bacillus subtilis, respectively, within 30min of contact times. Moreover, nearly 100% of the E. coli was killed after 2h during the filtration process for the PEK-N-Cl membrane. In addition, the water flux decreased by 42% for the PEK-N-Cl membrane compared to 77.6% for the PEK-NH membrane after filtration of the E. coli solution and incubation on LB nutrient agar plate, indicating that the PEK-N-Cl membrane enhibits antifouling. Furthermore, the PEK-N-Cl membrane is recyclable via subsequent exposure to a sodium hypochlorite solution.

  11. Oxidation of Tetracaine Hydrochloride by Chloramine-B in Acid Medium: Kinetic Modeling

    Directory of Open Access Journals (Sweden)

    Jayachamarajapura Pranesh Shubha

    2014-01-01

    Full Text Available Tetracaine hydrochloride (TCH is one of the potent local anaesthetics. A kinetic study of oxidation of tetracaine hydrochloride by sodium N-chlorobenzenesulfonamide (chloramine-B or CAB has been carried in HClO4 medium at 303 K. The rate shows first-order dependence on [CAB]o, shows fractional–order dependence on [substrate]o, and is self-governing on acid concentration. Decrease of dielectric constant of the medium, by adding methanol, increased the rate. Variation of ionic strength and addition of benzenesulfonamide or NaCl have no significant effect on the rate. The reaction was studied at different temperatures and the activation parameters have been evaluated. The stoichiometry of the reaction was found to be 1 : 5 and the oxidation products were identified by spectral analysis. The conjugate free acid C6H5SO2NHCl of CAB is postulated as the reactive oxidizing species. The observed results have been explained by plausible mechanism and the related rate law has been deduced.

  12. Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

    Science.gov (United States)

    Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

    2014-10-21

    Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

  13. Changes in dissolved organic matter fluorescence and disinfection byproduct formation from UV and subsequent chlorination/chloramination

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, Bonnie A.; Cory, Rose M.; Weinberg, Howard S., E-mail: howard_weinberg@unc.edu

    2014-01-15

    Highlights: • DBP formation from UV-chlorine/chloramine drinking water treatment was measured. • The effect of UV on DBP precursors was evaluated by fluorescence and PARAFAC. • UV alone decreased protein/tryptophan- and humic-like fluorescence. • Loss of two components correlated with cyanogen chloride formation (R{sup 2} = 0.79–0.91). • Loss of the components also correlated with chloral hydrate formation (R{sup 2} = 0.95–1.000). -- Abstract: Ultraviolet (UV) irradiation is being increasingly used to help drinking water utilities meet finished water quality regulations, but its influence on disinfection byproduct (DBP) precursors and DBP formation is not completely understood. This study investigated the effect of medium pressure (MP) UV combined with chlorination/chloramination on the fluorescent fraction of dissolved organic matter (DOM) isolated from a United States surface water with median total organic carbon content. Parallel factor analysis was used to understand how UV may alter the capacity of DOM to form DBPs of potential human health concern. The production of chloral hydrate and cyanogen chloride from MP UV followed by chlorine or chloramine, respectively, correlated with a decrease in fluorescence intensity of a protein/tryptophan-like component (R{sup 2} = 0.79–0.99) and a humic-like component (R{sup 2} = 0.91–1.00). This suggests that the UV-induced precursors to these compounds originated from DOM with similar characteristics to these components. The fluorescent DOM components identified in this study are similar to reoccurring components that have been previously identified in a range of raw and treated waters, and this work demonstrates the value of using fluorescence analysis of DOM to understand the relationships between DOM source and DBP formation under a range of treatment conditions.

  14. Formation of disinfection byproducts upon chlorine dioxide preoxidation followed by chlorination or chloramination of natural organic matter.

    Science.gov (United States)

    Yang, Xin; Guo, Wanhong; Lee, Wontae

    2013-06-01

    Chlorine dioxide (ClO2) is often used as an oxidant to remove taste, odor and color during water treatment. Due to the concerns of the chlorite formation, chlorination or chloramination is often applied after ClO2 preoxidation. We investigated the formation of regulated and emerging disinfection byproducts (DBPs) in sequential ClO2-chlorination and ClO2-chloramination processes. To clarify the relationship between the formation of DBPs and the characteristics of natural organic matter (NOM), changes in the properties of NOM before and after ClO2 oxidation were characterized by fluorescence, Fourier transform infrared spectroscopy (FTIR), and size and resin fractionation techniques. ClO2 preoxidation destroyed the aromatic and conjugated structures of NOM and transformed large aromatic and long aliphatic chain organics to small and hydrophilic organics. Treatment with ClO2 alone did not produce significant amount of trihalomethanes (THMs) and haloacetic acids (HAAs), but produced chlorite. ClO2 preoxidation reduced THMs, HAAs, haloacetonitriles (HANs) and chloral hydrate (CH) during subsequent chlorination, but no reduction of THMs was observed during chloramination. Increasing ClO2 doses enhanced the reduction of most DBPs except halonitromethanes (HNMs) and haloketones (HKs). The presence of bromide increased the formation of total amount of DBPs and also shifted DBPs to more brominated ones. Bromine incorporation was higher in ClO2 treated samples. The results indicated that ClO2 preoxidation prior to chlorination is applicable for control of THM, HAA and HAN in both pristine and polluted waters, but chlorite formation is a concern and HNMs and HKs are not effectively controlled by ClO2 preoxidation.

  15. Formation of emerging DBPs from the chlorination and chloramination of seawater algal organic matter and related model compounds

    KAUST Repository

    Nihemaiti, Maolida

    2014-05-01

    Limited studies focused on reactions occurring during disinfection and oxidation processes of seawater. The aim of this work was to investigate disinfection by-products (DBPs) formation from the chlorination and chloramination of seawater algal organic matter and related model compounds. Simulated algal blooms directly growing in Red Sea, red tide samples collected during an algal bloom event and Hymenomonas sp. monoculture were studied as algal organic matter sources. Experiments were conducted in synthetic seawater containing bromide ion. A variety of DBPs was formed from the chlorination and chloramination of algal organic matter. Brominated DBPs (bromoform, DBAA, DBAN and DBAcAm) were the dominant species. Iodinated DBPs (CIAcAm and iodinated THMs) were detected, which are known to be highly toxic compared to their chlorinated or brominated analogues. Algal organic matter was found to incorporate important precursors of nitrogenous DBPs (N-DBPs), which have been reported to be more toxic than regulated THMs and HAAs. Isotopically-labeled monochloramine (15N- NH2Cl) was used in order to investigate the nitrogen source in N-DBPs. High formation of N-DBPs was found from Hymenomonas sp. sample in exponential growth phase, which was enriched in nitrogen-containing organic compounds. High inorganic nitrogen incorporation was found from the algal samples enriched in humic-like compounds. HAcAms formation was studied from chlorination and chloramination of amino acids. Asparagine, aspartic acid and other amino acids with an aromatic structure were found to be important precursors of HAcAms and DCAN. Factors affecting HAcAms formation (Cl2/ amino acid molar ratio and pH) were evaluated. Studies on the formation kinetics of DCAcAm and DCAN from asparagine suggested a rapid formation of DCAcAm from organic nitrogen (amide group) and a slower incorporation of inorganic nitrogen coming from monochloramine to form DCAN. High amounts of DCAN and DCAcAm were detected from the

  16. Changes in dissolved organic matter fluorescence and disinfection byproduct formation from UV and subsequent chlorination/chloramination.

    Science.gov (United States)

    Lyon, Bonnie A; Cory, Rose M; Weinberg, Howard S

    2014-01-15

    Ultraviolet (UV) irradiation is being increasingly used to help drinking water utilities meet finished water quality regulations, but its influence on disinfection byproduct (DBP) precursors and DBP formation is not completely understood. This study investigated the effect of medium pressure (MP) UV combined with chlorination/chloramination on the fluorescent fraction of dissolved organic matter (DOM) isolated from a United States surface water with median total organic carbon content. Parallel factor analysis was used to understand how UV may alter the capacity of DOM to form DBPs of potential human health concern. The production of chloral hydrate and cyanogen chloride from MP UV followed by chlorine or chloramine, respectively, correlated with a decrease in fluorescence intensity of a protein/tryptophan-like component (R(2)=0.79-0.99) and a humic-like component (R(2)=0.91-1.00). This suggests that the UV-induced precursors to these compounds originated from DOM with similar characteristics to these components. The fluorescent DOM components identified in this study are similar to reoccurring components that have been previously identified in a range of raw and treated waters, and this work demonstrates the value of using fluorescence analysis of DOM to understand the relationships between DOM source and DBP formation under a range of treatment conditions.

  17. Immunotoxicological profile of chloramine in female B6C3F1 mice when administered in the drinking water for 28 days.

    Science.gov (United States)

    Guo, Tai L; Germolec, Dori R; Collins, Bradley J; Luebke, Robert W; Auttachoat, Wimolnut; Smith, Matthew J; White, Kimber L

    2011-01-01

    Monochloramine has been used to provide a disinfecting residual in water distribution systems where it is difficult to maintain an adequate free-chlorine residual or where disinfection by-product formation is of concern. The goal of this study was to characterize the immunotoxic effects of chloramine in female B(6)C(3)F(1) mice when administered via the drinking water. Mice were exposed to chloramine-containing deionized tap water at 2, 10, 20, 100, or 200 ppm for 28 days. No statistically significant differences in drinking water consumption, body weight, body weight gain, organ weights, or hematological parameters between the exposed and control animals were noted during the experimental period. There were no changes in the percentages and numbers of total B-lymphocytes, T-lymphocytes, CD4(+) and CD8(+) T-lymphocytes, natural killer (NK) cells, and macrophages in the spleen. Exposure to chloramine did not affect the IgM antibody-forming cell response to sheep red blood cells (SRBC) or anti-SRBC IgM antibody production. Minimal effects, judged to be biologically insignificant, were observed in the mixed-leukocyte response and NK activity. In conclusion, chloramine produced no toxicological and immunotoxic effects in female B(6)C(3)F(1) mice when administered for 28 days in the drinking water at concentrations ranging from 2-200 ppm.

  18. Mechanistic chemistry of oxidation of balsalazide with acidic chloramine-T and bromamine-T: A comparative spectrophotometric kinetic study

    Indian Academy of Sciences (India)

    Puttaswamy; S Dakshayani

    2014-11-01

    Balsalazide (BSZ) belongs to a class of non-steroidal anti-inflammatory drugs. Kinetics and mechanism of oxidation of BSZ with sodium N-halo-p-toluenesulfonamides viz., chloramine-T(CAT) and bromamine-T(BAT) in HClO4 medium have been spectrophotometrically investigated (max =357nm) at 303 K. Under comparable experimental conditions, reactions with both the oxidants follow a first-order dependence of rate on [BSZ] and fractional-order dependence on each [oxidant] and [HClO4]. Activation parameters and reaction constants have been computed. 2-hydroxy-5-nitroso-benzoic acid and 3-(4-nitroso-benzoylamino)-propionic acid are identified as the oxidation products of BSZ with both CAT and BAT. The rate of oxidation of BSZ is about five-fold faster with BAT than with CAT. Plausible mechanism and related rate law have been deduced for the observed kinetics.

  19. Depletion of the chloramine-T marker residue, para-toluenesulfonamide, from skin-on fillet tissue of hybrid striped bass, rainbow trout, and yellow perch

    Science.gov (United States)

    Meinertz, J.R.; Stehly, G.R.; Greseth, Shari L.; Gaikowski, M.P.; Gingerich, W.H.

    2004-01-01

    Waterborne exposure to n-sodium-n-chloro-p-toluenesulfonamide (chloramine-T) is an effective treatment for controlling fish mortalities caused by bacterial gill disease (BGD). Currently, data are being generated to gain United States Food and Drug Administration (FDA) approval for the use of chloramine-T in aquaculture. As part of the data required for an approval, depletion of the chloramine-T marker residue (para-toluenesulfonamide [p-TSA]) from the edible fillet tissue of exposed fish must be determined. Hybrid striped bass (Morone saxatilis??Morone chrysops; mean weight 357 g), rainbow trout (Oncorhynchus mykiss; mean weight 457 g), and yellow perch (Perca flavescens; mean weight 144 g) were exposed to 20 mg/l of chloramine-T for 60 min on 4 consecutive days (the most aggressive treatment expected for approved use in the United States). Groups of fish (n=15 or 19) were sampled immediately after the last treatment and periodically through 48 or 168 h after the treatment phase. Duplicate subsamples of skin-on fillet tissue from each fish were analyzed for p-TSA. Mean p-TSA concentrations in fillet tissue from fish sampled immediately after the last treatment were 142 ng/g (hybrid striped bass), 97 ng/g (rainbow trout), and 150 ng/g (yellow perch). Mean p-TSA concentrations at terminal sample times were 94 (168 h; hybrid striped bass), 74 (48 h; rainbow trout), and 35 ng/g (168 h; yellow perch). The half-lives of p-TSA in fillet tissue from fish near or at market size were 11.4 (hybrid striped bass), 4.3 (rainbow trout), and 3.2 days (yellow perch).

  20. Precursors and factors affecting formation of haloacetonitriles and chloropicrin during chlor(am)ination of nitrogenous organic compounds in drinking water.

    Science.gov (United States)

    Jia, Aiyin; Wu, Chunde; Duan, Yan

    2016-05-05

    This study investigated the precursors and factors affecting formation of haloacetonitriles (HANs) and chloropicrin (TCNM) during chlorination/chloramination of eight amino acids in the effluent water of V-type clarifying filtration from a drinking water treatment plant. The yields of trichloroacetonitrile (TCAN), dichloroacetonitrile (DCAN) and TCNM were higher during chlorination than during chloramination. Tyrosine and tryptophan produced the greatest amount of DCAN and also generated a small amount of TCAN during chlorination process. Besides, the yields of DCAN were higher than TCNM during chlorination/chloramination. Contact time, Cl2:org-N molar ratios, pH, temperature and bromide ion affected nitrogenous disinfection by-products (N-DBPs) formation during chlorination of tryptophan in different degrees. TCAN, DCAN and TCNM formation showed the increasing and then decreasing with prolonged contact time. Higher Cl2:org-N molar ratios improved N-DBPs formation within a certain range. The pH affected N-DBPs formation differently. HANs increased with increasing pH from 5 to 6 and decreased with increasing pH from 6 to 9, while TCNM increased with increasing pH from 5 to 9. Higher temperatures enhanced TCNM formation, but reduced the formation of TCAN and DCAN. The presence of bromide ions improved the yields of HANs and TCNM and shifted N-DBPs to more brominated ones.

  1. Impact of pre-ozonation on disinfection by-product formation and speciation from chlor(am)ination of algal organic matter of Microcystis aeruginosa.

    Science.gov (United States)

    Zhu, Mingqiu; Gao, Naiyun; Chu, Wenhai; Zhou, Shiqing; Zhang, Zhengde; Xu, Yaqun; Dai, Qi

    2015-10-01

    The increasing use of algal-impacted source waters is increasing concerns over exposure to disinfection byproducts (DBPs) in drinking water disinfection, due to the higher concentrations of DBP precursors in these waters. The impact of pre-ozonation on the formation and speciation of DBPs during subsequent chlorination and chloramination of algal organic matter (AOM), including extracellular organic matter (EOM) and intracellular organic matter (IOM), was investigated. During subsequent chlorination, ozonation pretreatment reduced the formation of haloacetonitriles from EOM, but increased the yields of trihalomethanes, dihaloacetic acid and trichloronitromethane from both EOM and IOM. While in chloramination, pre-ozonation remarkably enhanced the yields of several carbonaceous DBPs from IOM, and significantly minimized the nitrogenous DBP precursors. Also, the yield of 1,1-dichloro-2-propanone from IOM was decreased by 24.0% after pre-ozonation during chloramination. Both increases and decreases in the bromine substitution factors (BSF) of AOM were observed with ozone pretreatment at the low bromide level (50μg/L). However, pre-ozonation played little impact on the bromide substitution in DBPs at the high bromide level (500μg/L). This information was used to guide the design and practical operation of pre-ozonation in drinking water treatment plants using algae-rich waters.

  2. OXIDATION OF SALBUTAMOL BY CHLORAMINE-B IN HClO4 MEDIUM: A KINETIC AND MECHANISTIC APPROACH

    Directory of Open Access Journals (Sweden)

    Diwya

    2012-06-01

    Full Text Available Oxidation of Salbutamol (SBL by sodium – N- chloro benzenesulphonamide(Chloramine-B or CAB in HClO4 medium has been studied at 303K by kinetic method. Oxidation reaction follows first order kinetics with [CAB], positive fractional order dependence on [SBL] and negative fractional order dependence on [HClO4]. Effect of halide ions, added benzenesulphonamide had no effect on the rate of reaction. Variation in ionic strength had no effect on the rate of the reaction indicating that non-ionic species are involved in the rate limiting step. Dielectric effect of the medium showed negative effect. Kinetic parameters were evaluated by studying the reaction at different temperatures. Addition of reaction mixture to aqueous acrylamide did not initiate polymerization showing the absence of free radical species. Oxidation products were identified. TsNHCl of CAB, the reactive oxidant combines with the substrate to give the product. Based on kinetic results, reaction stoichiometry and oxidation products, a suitable mechanism have been proposed.

  3. Short communication: rapid preparation of preventive and therapeutic whole-killed retroviral vaccines using the microbicide taurine chloramine.

    Science.gov (United States)

    Dudani, A K; Martyres, A; Fliss, H

    2008-04-01

    A current urgent priority is to develop microbicides and vaccines to combat retroviruses like human immunodeficiency virus (HIV). We show that the cysteine-selective natural compound, taurine chloramine (T-NCl), can be effective in this task. A number of proteins in all retroviruses contain highly conserved cysteine-rich regions that are essential for infection and replication. Our data show that by targeting these essential cysteine residues, T-NCl (2 or 5 mM) acts as a highly effective and safe microbicide that fully blocks the infectivity of high HIV-1 titers (10(6) TCID(50) units/ml) but is not injurious to eukaryotic cells. We also demonstrate that T-NCl can be used to prepare a highly effective whole-killed vaccine against murine AIDS (MAIDS) that shows both preventive and therapeutic efficacy. The vaccine consists of a T-NCl-inactivated retrovirus suspension in host cell lysate. The novelty of our approach lies in the ease and speed of vaccine preparation and its avoidance of harsh inactivation or purification steps that can alter native viral conformation. Our approach is therefore likely to overcome a number of intractable obstacles to the preparation of an effective whole-killed HIV vaccine, such as surviving infective viral particles, rapid viral mutation rates, numerous viral strains, and harsh purification steps. Our approach may also permit the rapid preparation of autologous, or custom-made, vaccines for individual patients.

  4. OXIDATION OF PROPRANOLOL USING CHLORAMINE – T IN HClO4 MEDIUM: A KINETIC AND MECHANISTIC STUDY

    Directory of Open Access Journals (Sweden)

    Range Gowda Ramachandrappa

    2012-06-01

    Full Text Available Kinetics and oxidation of Propranolol (PPL ((RS-1-(1-methylethylamino-3-(1-naphthyloxypropan-2-ol by sodium – N- chloro – p- toluenesulphonamide (Chloramine – T or CAT in HClO4 medium at 298K have been studied. The rate was first order in [CAT]o, fractional order in [PPL] and zero order in [H+]. Addition of p-toluenesulphonamide, NaCl and NaBr did not affect the rate of the reaction. Variation in ionic strength did not affect the rate of the reaction indicating that non – ionic species are involved in the rate limiting step. The dielectric effect of the medium was positive. Rate increased with increase in temperature from 288K to 318K. From the linear Arrhenius plot, activation parameters were computed. Addition of reaction mixture to aqueous acrylonitrile solution did not initiate polymerization, showing the absence of free radicals species. Oxidation products were identified. TsNClNa, the reactive species, oxidizes the substrate. Based on kinetic results, reaction stoichiometry and oxidation products, a suitable mechanism have been proposed.

  5. Identification, toxicity and control of iodinated disinfection byproducts in cooking with simulated chlor(am)inated tap water and iodized table salt.

    Science.gov (United States)

    Pan, Yang; Zhang, Xiangru; Li, Yu

    2016-01-01

    Chlorine/chloramine residuals are maintained in drinking water distribution systems to prevent microbial contamination and microorganism regrowth. During household cooking processes (e.g., soup making), the residual chlorine/chloramines in tap water may react with the iodide in iodized table salt to form hypoiodous acid, which could react with remaining natural organic matter in tap water and organic matter in food to generate iodinated disinfection byproducts (I-DBPs). However, I-DBPs formed during cooking with chloraminated/chlorinated tap water are almost completely new to researchers. In this work, by adopting precursor ion scan of m/z 127 using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, many new polar I-DBPs formed during cooking with chloraminated/chlorinated tap water were detected and proposed with structures, of which 3-iodo-4-hydroxybenzaldehyde, 3-iodo-4-hydroxybenzoic acid, 3-iodo-4-hydroxy-5-methylbenzoic acid, diiodoacetic acid, 3,5-diiodo-4-hydroxybenzaldehyde, 3,5-diiodo-4-hydroxybenzoic acid, 2,6-diiodo-4-nitrophenol, 2,4-diiodo-6-nitrophenol, and 2,4,6-triiodophenol were confirmed with standard compounds. With the aid of ultra fast liquid chromatography/ion trap-time of flight-mass spectrometry, molecular formula identification of five new I-DBPs (C8H5O4I, C7H4NO4I, C8H5O5I, C7H4NO5I, and C8H6O3I2) was achieved. A developmental toxicity with a recently developed sensitive bioassay was conducted for the newly identified I-DBPs, suggesting that phenolic I-DBPs (except for iodinated carboxyphenols) were about 50-200 times more developmentally toxic than aliphatic I-DBPs. The major I-DBPs in a baseline simulated cooking water sample were determined to be from 0.72 to 7.63 μg/L. Polar I-DBPs formed under various disinfection and cooking conditions were compared, and suggestions for controlling their formation were provided.

  6. Histopathology of repeated, intermittent exposure of chloramine-T to walleye (Sander vitreum) and (Ictalurus punctalus) channel catfish

    Science.gov (United States)

    Gaikowski, M.P.; Densmore, Christine L.; Blazer, V.S.

    2009-01-01

    Chloramine-T (Cl-T) has been used safely and effectively to control bacterial gill disease in salmonids at a maximum exposure regimen of up to four consecutive, once-daily exposures administered for 60??min at 20??mg/L. However, data to document safe treatment concentrations of Cl-T are lacking for freshwater-reared fish other than salmonids. We report the histopathology resultant from the administration of 12 consecutive, once-daily, 180-min static immersion baths of 0, 20, 50, or 80??mg Cl-T/L to walleye (20????C) and channel catfish (27????C). Twelve fish of each species were euthanized immediately before the first exposure (initial controls) and then after the twelfth exposure and 7 and 14??days after the twelfth exposure. Only initial controls and fish euthanized immediately after the twelfth exposure were processed for histological review because of the general lack of exposure-related lesions in exposed fish. The only exposure-related histological changes were in the spleen where significantly greater erythrocyte swelling and necrosis was observed in channel catfish exposed at 80??mg/L relative to exposure at 0??mg/L; similar histological changes were insignificant for walleye, though there appeared to be a shift in the general category of histological change with degenerative changes (necrosis, etc.) observed following exposure at 50 or 80??mg/L compared to the inflammatory and hemodynamic changes (congestion, leukocyte infiltrate, etc.) observed in walleye exposed at 0 or 20??mg/L. The only significant change in peripheral blood cytology was that walleye fingerlings exposed at 80??mg/L had significantly fewer mature red blood cells and significantly more immature red blood cells per oil-immersion field than controls. The histopathological changes observed following exposure to Cl-T under an exaggerated exposure regimen suggest that walleye or channel catfish therapeutically exposed to Cl-T will not have treatment-related histological changes.

  7. Effects of two water disinfectants (chloramine T and peracetic acid) on the epidermis and gills of Garra rufa used in human ichthyotherapy.

    Science.gov (United States)

    Sirri, R; Zaccaroni, A; Di Biase, A; Mordenti, O; Stancampiano, L; Sarli, G; Mandrioli, L

    2013-01-01

    Doctor fish (Garra rufa) have recently been used for aesthetic purposes and as a medical treatment in patients with psoriasis (ichthyotherapy). For this particular kind of human therapy it is essential to guarantee adequate hygienic conditions for both people and fish. The aim of this study was to test two concentrations of water disinfectants, chloramine T and peracetic acid, on Garra rufa to ascertain possible exposure damage to the epidermis and gills. Fish were exposed to 2 mg/l and 10 mg/l of chloramine T and to 15 microl/l and 45 microl/l of peracetic acid in a 40-minute static bath up to six times a day for one week. The epidermis and gills were checked for histological changes and the number of epidermal mucous cells, club cells and taste buds were quantified; mucous cells were also characterized histochemically to detect alterations in mucin production. No mortality or severe histological changes were found in treated or control fish. Cell count showed a significant increase (p peracetic acid independently of the dose. Club cell number showed a significant (p peracetic acid (mean 78.17 +/- 10.5) compared to controls (mean 107.0 +/- 19.2). Histochemical evaluation of mucous cells did not reveal changes in mucin type in fish exposed to the two disinfectants. The results suggest a good tolerability of Garra rufa to the two disinfectants at the concentrations tested.

  8. Influence of Natural Organic Matter (NOM) Character on the Distribution of Chlorinated and Chloraminated Disinfection By-Products (DBPs) at Rand Water

    Science.gov (United States)

    Marais, Savia S.; Ncube, Esper J.; Haarhoff, Johannes; Msagati, Titus AM; Mamba, Bhekie B.; Nkambule, Thabo I.

    2016-04-01

    Certain disinfection by-products (DBPs) are likely human carcinogens or present mutagenic effects while many DBPs are unidentified. Considering the possibility of DBPs being harmful to human health and the fact that trihalomethanes (THMs) are the only regulated DBP in the South African National Standard (SANS:241) for drinking water, special interest in the precursors to these DBPs' formation is created. It is essential to understand the reactivity and character of the precursors responsible for the formation of DBPs in order to enhance precursor removal strategies during the treatment of drinking water. In this study the character of NOM within surface water and the subsequent distribution of THMs formed in the drinking water from Rand Waters' full scale treatment plant were investigated. Molecular size distribution (MSD) of NOM within the surface water was determined by high performance size exclusion chromatography (HPSEC). Specific ultraviolet absorbance (SUVA) and UV254 measurements formed part of the NOM character study as they provide an indication of the aromaticity of organic matter. The four THMs; bromoform, chloroform, dibromochloromethane (DBCM) and bromodichloromethane (BDCM)were measured by gas chromatography. The sum of these four THMs was expressed as total trihalomethane (TTHM). On average the chloroform constituted 76.2% of the total TTHM, BDCM 22.5% while DBCM and bromoform measured below the detection limit. THM speciation after chlorination and chloramination concentrations increased in the sequence bromoform water in summer when high temperatures and rainfall occurred. The results displayed are an indication that aromatic NOM were the main precursor to TTHM formation, more prominently during summer. Keywords: disinfection by-products, molecular size distribution, natural organic matter, UV254

  9. 氯胺消毒过程中碘代三卤甲烷生成的影响因素%Factors Affecting Iodo-trihalomethane Formation during Chloramination of Micro-polluted Raw Water

    Institute of Scientific and Technical Information of China (English)

    孙仲昊; 徐斌; 胡晨燕; 夏圣骥; 高乃云; 叶涛

    2013-01-01

    碘代消毒副产物的“三致”特性远高于氯代和溴代消毒副产物,是近年来饮用水领域颇受关注的一类新兴消毒副产物.以微污染原水为研究对象,系统研究了其在氯胺消毒条件下碘代三卤甲烷类消毒副产物生成的影响因素.研究发现,在原水中存在一定浓度碘离子的条件下,采用氯胺消毒可产生较高浓度的碘代三卤甲烷类消毒副产物,其中以三碘甲烷为主;碘代三卤甲烷的生成总量随着反应时间的增加而增加;碘代三卤甲烷的生成量和组成受氯胺投加量的影响较大,在氯胺投加量较低的情况下主要生成三碘甲烷和一溴二碘甲烷,在氯胺投加量较高的情况下生成一氯二碘甲烷、二氯一碘甲烷、一溴二碘甲烷和三碘甲烷四种碘代三卤甲烷;碘代三卤甲烷的生成总量以及三碘甲烷在总碘代三卤甲烷中的比例随着碘离子浓度的增加而提高;总体上,氯胺化过程中碘代三卤甲烷的生成总量随着pH值的升高而增加.%Iodinated disinfection byproducts contain higher mutagenesis, carcinogenesis and terat-ogenesis than chlorinated and brominated disinfection byproducts. Increasing attention is focused on these emerging byproducts in the drinking water field recently. The factors affecting iodo-trihalomethane formation during chloramination of micro-polluted raw water were investigated. The results showed that higher concentrations of iodo-trihalomethanes would be produced during chloramination in the presence of iodide in raw water, in which iodoform was predominant. The total amount of iodo-trihalomethanes increased with reaction time, and the total amount and species of iodo-trihalomethanes were influenced by chlora- mine dosage. Iodoform and bromodiiodomethane were generated by a relatively low chloramine dosage. With high chloramine dosage, four kinds of iodo-trihalomethanes including chlorodiiodomethane, di-chloroiodomethane, bromodiiodomethane

  10. Effect of Chloramine Auxiliary Disinfection and Organic Halide Content Change in Drinking Water%饮用水氯胺辅助消毒的效果及有机卤化物含量变化

    Institute of Scientific and Technical Information of China (English)

    李为兵; 陈雪芳; 袁哲; 陈卫

    2011-01-01

    Compared with chlorine disinfection, chloramine disinfection can effectively reduce the formation of disinfection byproducts.After chlorination in clear water tank, chloramine is used as auxiliary disinfectant to maintain the water quality in water distribution network in Kunshan City.The qualified rate of water quality at monitoring points rises from 92.8% to 99.5%, and the disinfection effect in water distribution network is distinctly improved.When the organic content is high, using chloramine auxiliary disinfection can reduce adsorbable organic halogens in drinking water by 48% comparing with the chlorine disinfection.Under the premise of ensuring the disinfection effect of treated water and water in clear water tank, the chlorine dosage in clear water tank should be reduced as far as possible to control the chlorine disinfection byproduct at a low level.Through the analysis of content of disinfection byproducts,such as trihalomethanes, chlorobenzene and haloacetic acids, it is confirmed that the chloramine disinfection may largely reduce the organic halide content in drinking water, which is consistent with the determination result of adsorbable organic halogen compounds.%与氯消毒相比,氯胺消毒能有效降低消毒副产物的生成量.昆山市在水厂清水池加氯消毒后,将氯胺用作维持管网水质的辅助消毒剂,使管网水质监测点的消毒剂余量和细菌总数合格率从92.8%上升到99.5%,管网消毒效果得到明显改善.在有机物含量较高的情况下,与氯消毒相比,采用氯胺辅助消毒可降低饮用水中可吸附有机卤素(AOX)含量达48%,因而在保证清水池和出厂水消毒效果的前提下,应尽量降低清水池的投氯量,以使氯消毒副产物含量控制在较低水平.通过对三卤甲烷、氯苯和卤乙酸等氯化消毒副产物含量的测定分析,证实氯胺消毒可大幅降低饮用水中的有机卤化物含量,这与对可吸附有机卤素的测定结果是一致的.

  11. 南水北调丹江口水库水氯(胺)化消毒副产物产生特性与消毒工艺对比%Formation of Disinfection By-Products During Chlor(am)ination of Danjiangkou Reservoir Water and Comparison of Disinfection Processes

    Institute of Scientific and Technical Information of China (English)

    张民盛; 徐斌; 张天阳; 程拓; 夏圣骥; 楚文海

    2015-01-01

    This study discussed the formation of volatile carbonaceous disinfection by-products (DBPs) and nitrogenous DBPs during chlor(am)ination of Danjingkou Reservoir water which was the source of the middle Route Project of South-to-North Water Diversion Project. The effects of disinfection methods, disinfectant dosage, reaction time, pH values and bromide ion concentration were investigated. And the disinfection parameters were optimized. Four DBPs, including chloroform ( CF), bromodichloromethane (BDCm), dichloroacetonitrile(DCAN) and trichloronitromethane(TCNm) , were observed during the chlorination. But only CF and TCNm were detected during the chloramination of water. The disinfection by-product (DBP) concentration from chlorination is 7. 5 times higher than that from chloramination, and the yield of DBPs from short time chlorination then chloramination is in between the first two methods. All kinds of DBPs detected increased with the dosage of increasing chlorine, but the increases slowed down when the dosage was higher than 2 mg·L - 1 . The formation of CF varied a little as the dosage of chloramine increasing. TCNm was detected when the chloramine dosage was greater than 2 mg·L - 1 . As reaction time going on, chlorine decayed much faster than chloramine, while DBP formation under chlorination was faster than that of chloramination. THm produced by chlorine increased with the increasing pH, while chloramination showed no obvious changes. As the bromide ion increasing, the species of DBPs transformed from chlorinated DBPs to brominated ones, and the total yield of DBPs increased during both chlorination and chloramination, but the former one was obviously more than that of the latter one. In order to reduce the risk of DBP formation, the chloramination is suggested in the treatment of water from Danjiangkou Reservoir. And if chlorination is applied, the disinfectant dosage should be controlled seriously.%系统研究了南水北调中线工程水源---丹江

  12. 顺序投加联合消毒剂二氧化氯氯胺对饮用水中消毒副产物的控制%Control of Disinfection Byproducts (DBPs)in Drinking Water by Sequential Dosing of Joint Disinfection with Chlorine Dioxide and Chloramine

    Institute of Scientific and Technical Information of China (English)

    易芳; 吴立波; 杨林锋; 叶竹兰; 万芬

    2015-01-01

    Traditional chlorine disinfection process has attracted wide attention because of its harmful disinfection byproducts. The control of disinfection byproducts in drinking water by sequential dosing of joint disinfectants with dioxide and chloramine was investigated in this study. The raw water was taken from filtration water in a waterworks in Tianjin,which was disinfected by the different doses combination of chlorine dioxide and chloramine. The results show that when dosage of chlorine dioxide is 0. 10 ~0. 50 mg / L and chloramine is 0. 50 ~ 1. 50 mg / L,the generation of disinfection byproducts can be effectively controlled,which meets the requirements of relevant standards.%传统氯消毒工艺因易生成对人体有害的消毒副产物被广泛关注,采用替代氯消毒工艺控制消毒副产物是目前的研究重点。该文以天津市某自来水厂滤后水为试验对象,采用二氧化氯氯胺顺序投加联合消毒工艺,分析了不同投加量组合对消毒副产物( THMs,HAAs和亚氯酸盐)产量的控制情况。结果表明当二氧化氯投加量为0.10~0.50 mg / L、氯胺投加量为0.50~1.50 mg / L时,消毒副产物的生成量均能得到有效控制,符合相关标准的要求。

  13. Titanium oxide nanotube arrays prepared by anodic oxidation method and photocatalytic degradation of chloramine phosphorus%阳极氧化法制备氧化钛纳米管阵列及光催化降解氯胺磷

    Institute of Scientific and Technical Information of China (English)

    龚青; 尹荔松; 郭智博; 阳素玉; 安科云

    2011-01-01

    Using anodic oxidation in HF+ACOH+PEG solution at the constant voltage to deal with the titanium foil, the high-density TiO2 nanotube arrays with regular and orderly structure were prepared. The morphology of the nanotubes was characterized by SEM, and the crystal of the nanotubes was analyzed by XRD. The effect of oxidation time on the morphology and size of nanotube arrays were studied, and the current-time curve was obtained. The photocatalytic activities were evaluated by degradation of chloramine phosphorus. The ratio of degradation was measured and calculated by Molybdenum- Antimony Anti-Spectrophotometric method. The influences of annealing temperature and anodic oxidation time of solution were analyzed. The sol-gel method was used to prepare TiC>2 thin film, which is used to do photocatalytic comparative experiments.%采用阳极氧化法在氢氟酸+冰醋酸+聚乙二醇水溶液恒压处理钛箔,制备结构规整有序的高密度TiO2纳米管阵列.利用电子扫描电镜(SEM)和X线衍射仪(XRD)对纳米管形貌和结构进行表征,考察氧化时间对纳米管阵列形貌和尺寸的影响,绘制并分析电流-时间曲线.选用有机磷药氯胺磷为光催化降解对象,利用钼锑抗分光光度法测量并计算降解率,研究不同热处理温度和阳极氧化时间对光催化降解效果的影响,并采用溶胶-凝胶法制备TiO2纳米薄膜进行光催化对比实验.

  14. Use of chloramine-T and two dyes in the sensitive determination of stavudine in pharmaceuticals Uso de cloramina-T e de dois corantes na determinação sensível de estavudina em medicamentos

    Directory of Open Access Journals (Sweden)

    Kanakapura Basavaiah

    2007-09-01

    Full Text Available Three new methods are described for the assay of stavudine (STV in bulk drug and in dosage forms using chloramine-T (CAT and two dyes, methyl orange and indigocarmine, as reagents. Titrimetry involves treating STV with a measured excess of CAT in hydrochloric acid medium, and after the oxidation of STV is judged to be complete, the unreacted oxidant is determined iodometrically. Spectrophotometric methods entail the addition of a known excess of CAT to STV in hydrochloric acid medium followed by determination of residual oxidant by reacting with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (Method A or indigo carmine and measuring the absorbance at 610 nm (Method B. In all the methods, the amount of CAT reacted corresponds to the amount of STV. In titrimetric method, the reaction follows 1:1 stoichiometry (STV: CAT, and is applicable over the range 1.5-10 mg of STV. In spectrophotometric methods, the absorbance is found to increase linearly with concentration of STV. The systems obey Beer's law for 0.2-2.0 and 1.0-10.0 mg/mL for method A and method B, respectively. The apparent molar absorptivities are calculated to be 5.7x10(4 and 1.5x10(4 L/mol/cm for method A and method B, respectively, and the corresponding Sandell sensitivity values are 0.004 and 0.015 µg/cm². The limits of detection and quantification are reported for both methods. Intra-day and inter-day precision and accuracy of the developed methods were evaluated as per the current ICH guidelines. The methods were successfully applied to the assay of STV in tablet and capsule formulations and the results were compared with those of a reference method by applying Student's t-test and F-test. No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained by performing recovery experiments via standard-addition method.Descrevem-se três novos métodos para o ensaio de estavudina (STV na mat

  15. Distribution of disinfection by-product formation potential by chlor(am)ination in three megalopolis along Yangtze river%长江沿线城市水源氯(胺)化消毒副产物生成潜能研究

    Institute of Scientific and Technical Information of China (English)

    黄河; 徐斌; 朱文倩; 秦朗; 马玉英

    2014-01-01

    Dissolved organic matter (DOM) in raw water from upper Yangtze River in Chongqing, middle Yangtze River in Wuhan, lower Yangtze River in Shanghai was isolated into fractions with different hydrophobicity and molecular weight (MW) by resin adsorption and ultra-filtration, respectively, to investigate and regulate emerging disinfection byproducts formation potential during chlorination and chloramination for each fraction. Research showted that DOM from Chongqing, Wuhan and Shanghai was mainly constituted of MW<1kDa organic compounds, hydrophilic and hydrophobic fractions. Trihalometheanes, haloketones, haloacetic acids, haloacetonitriles and chloropicrin were formed after chlorination and chloramination. Among three cities, MW<1kDa fractions gave the highest yield of carbonaceous disinfection byproducts (C-DBPs) and nitrogenous disinfection byproducts (N-DBPs), and the proportion of MW<1kDa formation potential tended to ascend from the upper Yangtze River to lower Yangtze River;Among all three megalopolis, hydrophobic fraction and hydrophilic fraction produced more C-DBPs and N-DBPs, the proportion of hydrophilic fraction C-DBPs and N-DBPs formation potential tended to ascend during chloramination.%以长江上游重庆、中游武汉、下游上海等大城市的长江饮用水源为研究对象,在对溶解性有机物分子量和亲疏水性分离的基础上,分别采用氯和氯胺两种方式消毒,对比分析了相同时期沿江这些城市原水中氯(胺)化常规和新兴含氮消毒副产物生成潜能的分子组成规律。研究表明,重庆、武汉、上海三地的溶解性有机物均以小分子前体物为主,主要分布在<1kDa 的区间内,且以强疏水性成分和亲水性成分为主,原水经氯(胺)化可产生三卤甲烷、卤乙酸、卤乙腈、三氯硝基甲烷等类型的消毒副产物;三地的氯(胺)化主要的含碳消毒副产物(C-DBPs)和含氮消毒副产物(N-DBPs)生成潜能均在<1kDa的区间内

  16. 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

  17. 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...

  18. Biofilm Community Dynamics in Bench-Scale Annular Reactors Simulating Arrestment of Chloraminated Drinking Water Nitrification

    Science.gov (United States)

    Annular reactors (ARs) were used to study biofilm community succession and provide an ecological insight during nitrification arrestment through simultaneously increasing monochloramine (NH2Cl) and chlorine to nitrogen mass ratios, resulting in four operational periods (I to IV)....

  19. Kinetics and Mechanism of Oxidation of Diethyl Ether by Chloramine-T in Acidic Medium

    Directory of Open Access Journals (Sweden)

    Y. I. Hassan

    2012-01-01

    Full Text Available The kinetics of oxidation of diethyl ether (DE with sodium N-chloro-p-toluenesulphonamide (CAT in hydrochloric acid solution has been studied at (313°K.The reaction rate show a first order dependence on [CAT] and fractional order dependence on each [DE] and [H+] .The variation of ionic strength of the medium has no significant effect on the reaction rate , addition of p-toluenesulphonamide (p-TSA affects the reaction rate marginally the rate increased with decreasing dielectric constant of the medium , the stochiometry of the reaction was found to be 1:2 and oxidation products were identified , A Michaelis – Menten type mechanism has been suggested to explain the results.The equilibrium and the decomposition constants of CAT – diethyl ether complex have been evaluated. Thermodynamic parameters were computed by studying reaction at temperatures range ( 308 – 323°K for the rate limiting step and for the observed first order constants by the linear Arrhenius plot. The mechanism proposed and the derived rate law are consistent with observed kinetics.

  20. Changes in physicochemical and transport properties of a reverse osmosis membrane exposed to chloraminated seawater.

    Science.gov (United States)

    Valentino, Lauren; Renkens, Tennie; Maugin, Thomas; Croué, Jean-Philippe; Mariñas, Benito J

    2015-02-17

    This study contributed to improving our understanding of how disinfectants, applied to control biofouling of reverse osmosis (RO) membranes, result in membrane performance degradation. We investigated changes in physicochemical properties and permeation performance of a RO membrane with fully aromatic polyamide (PA) active layer. Membrane samples were exposed to varying concentrations of monochloramine, bromide, and iodide in both synthetic and natural seawater. Elemental analysis of the membrane active layer by Rutherford backscattering spectrometry (RBS) revealed the incorporation of bromine and iodine into the polyamide. The kinetics of polyamide bromination were first order with respect to the concentration of the secondary oxidizing agent Br2 for the conditions investigated. Halogenated membranes were characterized after treatment with a reducing agent and heavy ion probes to reveal the occurrence of irreversible ring halogenation and an increase in carboxylic groups, the latter produced as a result of amide bond cleavage. Finally, permeation experiments revealed increases in both water permeability and salt passage as a result of oxidative damage.

  1. Changes in physicochemical and transport properties of a reverse osmosis membrane exposed to chloraminated seawater

    KAUST Repository

    Valentino, Lauren

    2015-02-17

    This study contributed to improving our understanding of how disinfectants, applied to control biofouling of reverse osmosis (RO) membranes, result in membrane performance degradation. We investigated changes in physicochemical properties and permeation performance of a RO membrane with fully aromatic polyamide (PA) active layer. Membrane samples were exposed to varying concentrations of monochloramine, bromide, and iodide in both synthetic and natural seawater. Elemental analysis of the membrane active layer by Rutherford backscattering spectrometry (RBS) revealed the incorporation of bromine and iodine into the polyamide. The kinetics of polyamide bromination were first order with respect to the concentration of the secondary oxidizing agent Br2 for the conditions investigated. Halogenated membranes were characterized after treatment with a reducing agent and heavy ion probes to reveal the occurrence of irreversible ring halogenation and an increase in carboxylic groups, the latter produced as a result of amide bond cleavage. Finally, permeation experiments revealed increases in both water permeability and salt passage as a result of oxidative damage.

  2. Integrated Chemical and Toxicological Investigation of UV-Chlorine/Chloramine Drinking Water Treatment

    Science.gov (United States)

    As the use of alternative drinking water treatment increases, it is important to understand potential public health•implications associated with these processes. The objective of this study was to evaluate the formation of disinfection byproducts (DBPs) and cytotoxicity of ...

  3. [First results on the use of chloramines to reduce disinfection byproducts in drinking water].

    Science.gov (United States)

    Azara, Antonio; Muresu, Elena; Dettori, Marco; Ciappeddu, Pierluigi; Deidda, Antonio; Maida, Alessandro

    2010-01-01

    The presence of disinfection byproducts (DBP) in drinking water raises concerns about the safety of chlorination and is one of the problems inherent the use of surface water as a source of drinking water. In order to reduce the presence of DBP (in particular of chlorites), we evaluated the combined use of chlorine dioxide for primary disinfection and monochloramine for residual disinfection in a water purification plant and distribution system in Sardinia (Italy). The results are very encouraging. Disinfection byproducts were reduced and other parameters were found to be within the recommended standards, indicating further improvements of the purification process.

  4. Characterization of chlorinated and chloraminated drinking water microbial communities in a distribution system simulator using pyrosequencing data analysis

    Science.gov (United States)

    The molecular analysis of drinking water microbial communities has focused primarily on 16S rRNA gene sequence analysis. Since this approach provides limited information on function potential of microbial communities, analysis of whole-metagenome pyrosequencing data was used to...

  5. KINETICS OF OXIDATION OF SALBUTAMOL BY CHLORAMINE-B IN NaOH MEDIUM: A MECHANISTIC APPROACH

    Directory of Open Access Journals (Sweden)

    Iyengar Pushpa

    2012-04-01

    Full Text Available The kinetics of oxidation of salbutamol (SBL by N-chlorobenzenesulphonamide (CAB in NaOH medium has been investigated at 303K. The reaction rate shows a first order dependence on [CAB]0 , fractional order with respect to [SBL]0 and a negative fractional order with respect to [OH-] . The addition of the reduction product, benzenesulphonamide , retards the reaction rate. The effect of dielectric constant of the medium by varying [MeOH] shows an inverse effect. The addition of chloride ions and variation of ionic strength of the medium have no significant effect on the rate of the reaction. The reaction fails to initiate polymerization of acrylamide. The oxidation products were identified. The Michaelis – Menten type of kinetics has been proposed. The reaction was studied at different temperatures and the values of thermodynamic parameters were computed. A mechanism consistent with the observed kinetics is proposed.

  6. CHARACTERIZING THE EFFECT OF CHLORINE AND CHLORAMINES ON THE FORMATION OF BIOFILM IN A SIMULATED DRINKING WATER DISTRIBUTION SYSTEM

    Science.gov (United States)

    Drinking wate treatment in the US has played a major role in protecting public health through the reduction of wateborne disease. However, carcinogenic and toxic contaminants continue to threaten the quality of surface and ground water in the US. The passage of the Safe Drinking ...

  7. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Science.gov (United States)

    2010-07-01

    ... disinfection profile in addition to the Giardia lamblia disinfection benchmark calculated under § 141.543. This viral benchmark must be calculated in the same manner used to calculate the Giardia lamblia...

  8. Secondary radicals derived from chloramines of apolipoprotein B-100 contribute to HOCl-induced lipid peroxidation of low-density lipoproteins

    DEFF Research Database (Denmark)

    Hazell, L J; Davies, Michael Jonathan; Stocker, R

    1999-01-01

    by an extended period of lipid peroxidation during which further protein oxidation does not occur. The secondary lipid peroxidation process involves EPR-detectable radicals, is attenuated by a radical trap or treatment of HOCl-oxidized LDL with methionine, and occurs less rapidly when the lipoprotein...... was depleted of alpha-tocopherol. The initial reaction of low concentrations of HOCl (400-fold or 800-fold molar excess) with LDL therefore seems to occur primarily by two-electron reactions with side-chain sites on apolipoprotein B-100. Some of the initial reaction products, identified as lysine...

  9. Resilience of microbial communities in a simulated drinking water distribution system subjected to disturbances: role of conditionally rare taxa and potential implications for antibiotic-resistant bacteria

    Science.gov (United States)

    Many US water utilities using chloramine as their secondary disinfectant have experienced nitrification episodes that detrimentally impact water quality in their distribution systems. A semi-closed pipe-loop chloraminated drinking water distribution system (DWDS) simulator was u...

  10. 氯胺消毒工艺在郊区水厂的应用实践%Applications and Practice of Disinfection Process with Chloramine in Suburban Water Treatment Plants

    Institute of Scientific and Technical Information of China (English)

    张华军

    2012-01-01

    Raw water of Nanhui district suburb water plant is of high concentration of CODMn, and NH3-N with large seasonal variation. Ammonia dosing system was added in water treatment processes, which made effluent NH,-N maintain 0.5 mg/L at the outlet sedimentation tank. The results show this measure is helpful to ensure the residual chlorine stability in distribution network and lower the concentrations of disinfection by-products (DBPs). However, water treatment cost increases by 0.008 RMB/t, removal rate of total bacteria count and color decreases after this measures is used.%该文介绍了上海浦东新区南汇地区郊区水厂的原水具有高耗氧量、高氨氮、季节性变化大的特点.通过在自来水制水工艺中增添加氨装置,控制沉淀池出水氨氮为0.5 mg/L左右;采用化合氯消毒后,可有效保证管网余氯稳定性和控制消毒副产物,但该方法也存在菌落总数检出率和色度升高及制水成本提高约0.008元/t的问题.

  11. Study of Effect of Variation of Ionic Strength of the Medium on Velocity Constant of Ru(Iii Catalyzed Oxidation of Hydroxy Benzoic Acids by Chloramine-T in Acidic Medium

    Directory of Open Access Journals (Sweden)

    Dr. Parmod Kumar

    2014-01-01

    Full Text Available In the present study the effect of variation of ionic strength of the medium on rate of oxidation of hydroxy benzoic acids as its effect provides some clues regarding the nature of reactive species involved in the rate determining step. In order to realize the above aim the experiments has been carried out which ultimately concluded that ionic strength variation does not change the reaction velocity constant significantly.

  12. LJFO00000000, LJFQ00000000, LJFT00000000, LJFU00000000, LJFX00000000, LJFY00000000

    Data.gov (United States)

    U.S. Environmental Protection Agency — Draft genome sequences of six Mycobacterium immunogenum strains isolated from a chloraminated drinking water distribution system simulator subjected to changes in...

  13. 40 CFR 142.60 - Variances from the maximum contaminant level for total trihalomethanes.

    Science.gov (United States)

    2010-07-01

    ... chloramines, chlorine dioxide or potassium permanganate. (5) Use of powdered activated carbon for THM precursor or TTHM reduction seasonally or intermittently at dosages not to exceed 10 mg/L on an...

  14. MONITORING FOR AEROMONAS SPECIES AFTER TREATMENT WITH COMMON DRINKING WATER DISINFECTANTS

    Science.gov (United States)

    The sensitivity of Aeromonas spp. To free chlorine, chloramine and ultraviolet (UV) disinfection was determined. Aeromonas hydrophila is a contaminant listed on the USEPA's 1998 Contaminant Candidate List (CCL). Experiments using free chlorine indicated that the Aeromonas spp. ...

  15. IDENTIFICATION OF NEW DISINFECTION BY-PRODUCTS IN DRINKING WATER

    Science.gov (United States)

    Due to concern over the potential adverse health effects of trihalomethanes (THMs) and other chlorinated by-products in chlorinated drinking water, alternative disinfectants are being explored. Ozone, chlorine dioxide, and chloramine are popular alternatives, as they produce low...

  16. Draft Genome Sequence of Two Sphingopyxis sp. Strains, Dominant Members of the Bacterial Community Associated with a Drinking Water Distribution System Simulator

    Science.gov (United States)

    We report the draft genome of two Sphingopyxis spp. strains isolated from a chloraminated drinking water distribution system simulator. Both strains are ubiquitous residents and early colonizers of water distribution systems. Genomic annotation identified a class 1 integron (in...

  17. Superoxide radicals can act synergistically with hypochlorite to induce damage to proteins

    DEFF Research Database (Denmark)

    Hawkins, Clare Louise; Rees, Martin D; Davies, Michael Jonathan

    2002-01-01

    Activated phagocytes generate both superoxide radicals via a respiratory burst, and HOCl via the concurrent release of the haem enzyme myeloperoxidase. Amine and amide functions on proteins and carbohydrates are major targets for HOCl, generating chloramines (RNHCl) and chloramides (RC(O)NClR'), ......Activated phagocytes generate both superoxide radicals via a respiratory burst, and HOCl via the concurrent release of the haem enzyme myeloperoxidase. Amine and amide functions on proteins and carbohydrates are major targets for HOCl, generating chloramines (RNHCl) and chloramides (RC......(O)NClR'), which can accumulate to high concentrations (>100 microM). Here we show that superoxide radicals catalyse the decomposition of chloramines and chloramides to reactive nitrogen-centred radicals, and increase the extent of protein fragmentation compared to that observed with either superoxide radicals...... or HOCl, alone. This synergistic action may be of significance at sites of inflammation, where both superoxide radicals and chloramines/chloramides are formed simultaneously....

  18. Chemistry, Toxicity and Health Risk Assessment of Drinking Water Disinfection ByProducts

    Science.gov (United States)

    Disinfection byproducts (DBPs) are formed by the reaction of oxidizing chemicals (such as chlorine, ozone and chloramines) used to control waterborne pathogens with natural organic material and other substances in water. DBP mixture composition varies as a function of geographic ...

  19. Formation and Occurrence of Disinfection By-Products

    Science.gov (United States)

    Disinfection by-products (DBPs) are formed when disinfectants such as chlorine, ozone, chlorine dioxide, or chloramines react with naturally occurring organic matter, anthropogenic contaminants, bromide, and iodide during the production of drinking water. There is concern about D...

  20. ALTERNATIVE DISINFECTANTS FOR DRINKING WATER TREATMENT

    Science.gov (United States)

    During a one-year study at Jefferson Parish, Louisiana the chemical, microbiological, and mutagenic effects of using the major drinking water disinfectants (chlorine, chlorine dioxide, chloramine, ozone) were evaluated. ests were performed on samples collected from various treatm...

  1. ALTERNATIVE DISINFECTION FOR DRINKING WATER TREATMENT

    Science.gov (United States)

    During a one-yr study at Jefferson Parish, La., the chemical, microbiological, and mutagenic effects os using the major drinkgin water disinfectants (chlorine, chlorine dioxide, chloramine, ozone) were evaluated. Tests were performed on samples collected from various treatment s...

  2. 氯胺T氧化孔雀绿动力学光度法测定食品中痕量碘%Kinetic-Spectrophotometric Determination of Trace Iodine in Food with the Oxidation Reaction of Malachite Green by Chloramine T

    Institute of Scientific and Technical Information of China (English)

    李建国; 乔艳; 魏永前

    1999-01-01

    基于在稀盐酸介质中,碘催化氯胺T氧化孔雀绿而使其褪色的反应,建立了测定痕量碘的新方法.测定碘的线性范围为0~80 μg/L;检出限为1.6μg/L.方法灵敏、简便、选择性好,用于食品中痕量碘的测定,结果满意.

  3. 氯胺消毒对饮用水消毒副产物形成和致突变性的影响%Effect of Chloramine Disinfection on the Formation of Drinking Water Disinfection By-Products and Their Mutagenicity

    Institute of Scientific and Technical Information of China (English)

    衡正昌; 李朝晖; 姜维华; 谢海英

    2003-01-01

    目的评价氯胺消毒对饮用水消毒副产物形成和致突变性的影响.方法分别于2001年8月(丰水期)和2002年3月(枯水期)对成都市某水厂氯胺消毒和液氯消毒饮用水的细菌学指标以及氯仿、四氯化碳含量进行了检测,对其水样的有机浓集物进行了Ames试验,然后比较两种消毒饮用水的消毒副产物含量和致突变性.结果用氯胺消毒的饮用水中余氯量约1 mg/L时均未检出细菌总数和大肠菌群,且氯仿含量较用液氯消毒减少了81%~84%,两种消毒方式的饮水中四氯化碳含量均小于0.2μg/L.对于TA98菌株,液氯消毒的出厂水1.5 L检出阳性反应,而氯胺消毒检出阳性反应的水样量≥6.0 L.结论采用氯胺消毒可以明显降低饮用水氯化副产物的含量和致突变性,其消毒效果不亚于氯化消毒,因此,氯胺是较好的替代消毒剂.

  4. Evaluation and Refinement of a Field-Portable Drinking Water Toxicity Sensor Utilizing Electric Cell-Substrate Impedance Sensing and a Fluidic Biochip

    Science.gov (United States)

    2014-01-01

    described here operates on the same principle as the laboratory-based version described previously (Brennan et al., 2012), but now utilizes a hand -held...Potential interferences tested were chlorine and chloramine (commonly used for drinking water disinfection ), geosmin and 2-methyl-isoborneol (MIB...Protection Agency maximum residual disinfectant level for chlorine and chloramine is set at 4 mg l1 under the Safe Drinking Water Act and thus would

  5. FATE OF REVERSE OSMOSIS (RO) MEMBRANES DURING OXIDATION BY DISINFECTANTS USED IN WATER TREATMENT: IMPACT ON MEMBRANE STRUCTURE AND PERFORMANCES

    KAUST Repository

    Maugin, Thomas

    2013-12-01

    Providing pretreatment prior RO filtration is essential to avoid biofouling and subsequent loss of membrane performances. Chlorine is known to degrade polymeric membrane, improving or reducing membrane efficiency depending on oxidation conditions. This study aimed to assess the impact of alternative disinfectant, NH2Cl, as well as secondary oxidants formed during chloramination of seawater, e.g. HOBr, HOI, or used in water treatment e.g. ClO2, O3, on membrane structure and performances. Permeability, total and specific rejection (Cl-, SO4 2-, Br-, Boron), FTIR profile, elemental composition were analyzed. Results showed that each oxidant seems to react differently with the membrane. HOCl, HOBr, ClO2 and O3 improved membrane permeability but decreased rejection in different extent. In comparison, chloramines resulted in identical trends but oxidized membrane very slowly. On the contrary, iodine improved membrane rejection e.g. boron, but decreased permeability. Reaction conducted with chlorine, bromine, iodine and chloramines resulted in the incorporation of halogen in the membrane structure. All oxidant except iodine were able to break amide bonds of the membrane structure in our condition. In addition, chloramine seemed to react with membrane differently, involving a potential addition of nitrogen. Chloramination of seawater amplified membrane performances evolutions due to generation of bromochloramine. Moreover, chloramines reacted both with NOM and membrane during oxidation in natural seawater, leading to additional rejection drop.

  6. A picture of polar iodinated disinfection byproducts in drinking water by (UPLC/)ESI-tqMS.

    Science.gov (United States)

    Ding, Guoyu; Zhang, Xiangru

    2009-12-15

    Iodinated disinfection byproducts (DBPs) are generally more toxic than their chlorinated and brominated analogues. Up to date, only a few iodinated DBPs in drinking water have been identified by gas chromatography/mass spectrometry. In this work, a method for fast selective detection of polar iodinated DBPs was developed using an electrospray ionization-triple quadrupole mass spectrometer (ESI-tqMS) by conducting precursor ion scan of iodide at m/z 126.9. With such a method, pictures of polar iodinated DBPs in chlorinated, chloraminated, and chlorine-ammonia treated water samples were achieved. By coupling state-of-the-art ultra performance liquid chromatography (UPLC) to the ESI-tqMS, structures of 17 iodinated DBPs were tentatively proposed. The results fully demonstrate that, with respect to the DBP number/levels among the three disinfection processes, chloramination generally generated the most/highest iodinated DBPs, chlorination generally produced the fewest/lowest iodinated DBPs, and chlorine-ammonia sequential treatment formed iodinated DBPs lying in between; the numbers of iodinated DBPs in chloraminated Suwannee River Fulvic Acid (SRFA) and Humic Acid (SRHA) were nearly the same, but the levels of aliphatic iodinated DBPs were higher in the chloraminated SRFA while the levels of aromatic iodinated DBPs were higher in the chloraminated SRHA; a couple of nitrogenous iodinated DBPs were found in chloramination and chlorine-ammonia treatment. The ratio of total organic iodine levels in chlorine-ammonia sequential treatment and chloramination could be expressed as a function of the lag time of ammonia addition.

  7. Effect of pipe material and low level disinfectants on biofilm development in a simulated drinking water distribution system

    Institute of Scientific and Technical Information of China (English)

    Ling-ling ZHOU; Yong-ji ZHANG; Gui-bai LI

    2009-01-01

    The efficiency of chlorine and chloramines disinfection on biofilm development in a simulated drinking water distribution system was investigated by using heterotrophic bacterial spread plate technique.The experiments were carried out with four annular reactors(ARs)with stainless steel(SS)or copper(Cu)material slides.The results showed that there were fewer bacteria attached to Cu slides without a disinfectant compared with those attached to SS slides.When the water was disinfected with chloramines,the heterotrophic plate counts(HPCs)on the biofilm attached to the Cu slides were significantly lower(by 3.46 log CFU/cm2)than those attached to the SS slides.Likewise,the biofilm HPC numbers on the Cu slides were slightly lower(by 1.19log CFU/cm2) than those on the SS slides disinfected with chlorine.In a quasi-steady state.the HPC levels on Cu slides can be reduced to 3.0 log CFU/cm2 with chlorine and to about 0.9 log CFU/cm2 with chloramines.The addition of chloramines resulted in a more efficient reduction of biofilm heterotrophic bacteria than did chlorine.We concluded that the chlorine and chloramines levels usually employed in water distribution system were not SUfficient to prevent the growth and development of microbial biofilm.The combination of copper pipe slides and chlorarnincs as the disinfectant was the most efficient combination to bring about diminished bacterial levels.

  8. Is nothing sacred?

    Science.gov (United States)

    Hoffman, G.L.

    1980-01-01

    N-sodium-N-chloro-rho-toluenesulfonamide (chloramine-T) effectively controls bacterial gill disease (BGD) in cultured fishes, BGD, a common disease of hatchery-reared salmonids, causes more fish losses than any other disease among these species, This study describes a liquid chromatographic (LC) method that is capable of direct, simultaneous analysis of chloramine-T and its primary degradation product, rho-toluenesulfonamide (rho-TSA), in water. The procedure involves reversed-phase (C-18) LC analysis with ion suppression, using 0.01 M phosphate buffer at pH 3. The mobile phase is phosphate buffer-acetonitrile (60 + 40) at 1 mL/min. Both chemicals can be detected with a UV spectrophotometer at 229 nm; the method is linear up to 40 mg, chloramine-T or rho-TSA/L. Mean recoveries were 96.4 +/- 6.1% for water samples fortified with 0.03 mg chloramine-T/L and 95.3 +/- 4.6% for water samples fortified with 0.005 mg rho-TSA/L. Limits of detection without sample enrichment for chloramine-T and rho-TSA are 0.01 mg/L and 0.001 mg/L, respectively.

  9. Biological stability in drinking water: a regression analysis of influencing factors

    Institute of Scientific and Technical Information of China (English)

    LU Wei; ZHANG Xiao-jian

    2005-01-01

    Some parameters, such as assimilable organic carbon(AOC), chloramine residual, water temperature, and water residence time, were measured in drinking water from distribution systems in a northern city of China. The measurement results illustrate that when chloramine residual is more than 0.3 mg/L or AOC content is below 50 tμg/L, the biological stability of drinking water can be controlled.Both chloramine residual and AOC have a good relationship with Heterotrophic Plate Counts(HPC)(log value), the correlation coefficient was -0.64 and 0.33, respectively. By regression analysis of the survey data, a statistical equation is presented and it is concluded that disinfectant residual exerts the strongest influence on bacterial growth and AOC is a suitable index to assess the biological stability in the drinking water.

  10. NDMA formation kinetics from three pharmaceuticals in four water matrices.

    Science.gov (United States)

    Shen, Ruqiao; Andrews, Susan A

    2011-11-01

    N, N-nitrosodimethylamine (NDMA) is an emerging disinfection by-product (DBP) that has been widely detected in many drinking water systems and commonly associated with the chloramine disinfection process. Some amine-based pharmaceuticals have been demonstrated to form NDMA during chloramination, but studies regarding the reaction kinetics are largely lacking. This study investigates the NDMA formation kinetics from ranitidine, chlorphenamine, and doxylamine under practical chloramine disinfection conditions. The formation profile was monitored in both lab-grade water and real water matrices, and a statistical model is proposed to describe and predict the NDMA formation from selected pharmaceuticals in various water matrices. The results indicate the significant impact of water matrix components and reaction time on the NDMA formation from selected pharmaceuticals, and provide fresh insights on the estimation of ultimate NDMA formation potential from pharmaceutical precursors.

  11. Impact of disinfection on drinking water biofilm bacterial community.

    Science.gov (United States)

    Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-11-01

    Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination.

  12. Effect of pre-ozonation on the formation and speciation of DBPs.

    Science.gov (United States)

    Hua, Guanghui; Reckhow, David A

    2013-09-01

    The objective of this study was to quantitatively evaluate the effect of pre-ozonation on the formation and speciation of disinfection byproducts (DBPs) from subsequent chlorination and chloramination. Laboratory experiments were conducted on six diverse natural waters with low to medium bromide concentrations. Four groups of DBPs were investigated in this study: trihalomethanes (THMs), trihaloacetic acids (THAAs), dihaloacetic acids (DHAAs), and dihaloacetonitriles (DHANs). The results showed that the relative destructions of chlorination DBP precursors by ozone generally follow the order of DHANs > THMs & THAAs > DHAAs. Pre-ozonation substantially increased the DHAA precursors in the waters with low specific ultraviolet absorbance values. Pre-ozonation shifted the formation of DBPs to more brominated species. The bromine substitution factors (BSF) of different chlorination DBPs typically increased by 1-8 percentage points after ozonation. Pre-ozonation reduced the yields of chloramination DHAAs and THMs and increased the BSFs of chloramination DHAAs by 1-6 percentage points.

  13. Hypochlorite-induced damage to DNA, RNA, and polynucleotides

    DEFF Research Database (Denmark)

    Hawkins, Clare L; Davies, Michael Jonathan

    2002-01-01

    on the nature of the nucleobase on which they are formed, with chloramines formed from ring heterocyclic amine groups being less stable than those formed on exocyclic amines (RNH2 groups). Evidence is presented for chlorine transfer from the former, kinetically favored, sites to the more thermodynamically...... favored exocyclic amines. EPR experiments have also provided evidence for the rapid addition of pyrimidine-derived nitrogen-centered radicals to other nucleobases to give dimers and the oxidation of DNA by radicals derived from preformed nucleoside chloramines. Direct reaction of HOCl with plasmid DNA...

  14. Preparation and characterization of 125 I labeled bovine serum albumin

    Directory of Open Access Journals (Sweden)

    K S Ashwitha Rai

    2015-01-01

    Full Text Available Bovine serum albumin is a model protein, which has been conventionally used as protein standard and in many areas of biochemistry, pharmacology and medicine. Radioiodination procedure for bovine serum albumin employing chloramine-T as an oxidant with slight modification was evaluated critically to establish the optimal conditions for the preparation of radiolabeled tracer ( 125 I-BSA with required specific activity without impairing the immune reactivity and biological activity. Optimized radioiodination procedure involving 10 µg of chloramine-T along with 20 µg of sodium metabisulphite with 60 seconds incubation at 2° yielded 125 I-BSA with high integrity.

  15. [Preliminary assessment of the effect of disinfectants on skin changes in health service workers].

    Science.gov (United States)

    Kieć-Swierczyńska, M

    1995-01-01

    During a five-year period (1 Jan. 1989 and 31 Oct. 1994) epidermal tests with disinfectants (formalin, sterinol, lysoformin, aldesan, septyl, chloramine, lysol, chlorhexidine) and their components (glutaraldehyd, phenol, hydroquinone) were performed on 322 health service workers examined at the Nofer Institute of Occupational Medicine due to suspected occupational dermatitis. It was found that 89 (27.6%) subjects examined were oversensitive, at least, to one disinfectant, mostly to formalin, sterinol (benzalkonium bromide), lysoformin and chloramine. Frequent occurrence of allergy to metals (nickel, cobalt, chromium, mercury) was observed in persons oversensitive to disinfectants.

  16. Microelectrode investigation of the reactions between metallic pipe materials and monochloramine

    Science.gov (United States)

    Water quality parameters (i.e., pH, dissolved oxygen [DO], and phosphate) are known to impact metal reactivity with disinfectants and therefore corrosion and metals release into drinking water supplies. With various water utilities switching from free chlorine to chloramines for ...

  17. Improved radioimmunotherapy of hematologic malignancies. Progress report, November 1, 1993--October 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Press, O.W.

    1994-08-04

    This report summaries progress made during the time interval between November 1, 1993 and October 31, 1994 and briefly describes studies on the metabolism of antibodies targeting B cell antigens, retention of labeled antibodies by human B cell lymphocytes, and tissue distribution of Chloramine T and tyramine cellobiose labeled antibodies in mice harboring a human erythroleukemia tumor transplant.

  18. Zebra Mussel Chemical Control Guide, Version 2.0

    Science.gov (United States)

    2015-07-01

    28 Ammonia ...controlling zebra mussels (Dreissena polymorpha): A synthesis of recent laboratory and field studies. In: Zebra mussels: Biology, impacts, and control, ed. T...15-9 18 These FAC compounds react with ammonia and other nitrogen-containing compounds to make chloramines, which also contribute to disinfection

  19. Photolytic removal of DBPs by medium pressure UV in swimming pool water

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Zortea, R.; Piketty, A.;

    2013-01-01

    Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported ...

  20. Synthesis of new series of 4, 5-dihydroisoxazole-5-carboxylate derivatives for the study of their liquid crystalline properties

    Indian Academy of Sciences (India)

    SUMANA Y KOTIAN; NARAYANA U KUDVA N; K M LOKANATHA RAI; K BYRAPPA

    2016-07-01

    A new series of 4,5-dihydroisoxazole-5-carboxylate derivatives were synthesized via [3+2] cycloaddition reaction between ethyl acrylate and nitrile oxide generated in situ in presence of Chloramine-T. The synthesized derivatives were characterized by Mass, IR and NMR Spectroscopy and their mesomorphic behavior were studied using DSC and Polarising Optical Microscopy.

  1. OVERVIEW: DISINFECTION OF HELICOBACTER PYLORI AND AEROMONAS SPECIES

    Science.gov (United States)

    Helicobacter pylori and Aeromonas hydrophila are contaminants listed on the USEPA's 1998 Contaminant Candidate List (CCL).The sensitivity of H. pylori to chlorine and of Aeromonas spp. to inactivation by free chlorine, chloramine and ultraviolet (UV) was examined. Selective and...

  2. Changes in the Expression of Biofilm-Associated Surface Proteins in Staphylococcus aureus Food-Environmental Isolates Subjected to Sublethal Concentrations of Disinfectants.

    Science.gov (United States)

    Cincarova, Lenka; Polansky, Ondrej; Babak, Vladimir; Kulich, Pavel; Kralik, Petr

    2016-01-01

    Sublethal concentrations (sub-MICs) of certain disinfectants are no longer effective in removing biofilms from abiotic surfaces and can even promote the formation of biofilms. Bacterial cells can probably adapt to these low concentrations of disinfectants and defend themselves by way of biofilm formation. In this paper, we report on three Staphylococcus aureus biofilm formers (strong B+++, moderate B++, and weak B+) that were cultivated with sub-MICs of commonly used disinfectants, ethanol or chloramine T, and quantified using Syto9 green fluorogenic nucleic acid stain. We demonstrate that 1.25-2.5% ethanol and 2500 μg/mL chloramine T significantly enhanced S. aureus biofilm formation. To visualize differences in biofilm compactness between S. aureus biofilms in control medium, 1.25% ethanol, or 2500 μg/mL chloramine T, scanning electron microscopy was used. To describe changes in abundance of surface-exposed proteins in ethanol- or chloramine T-treated biofilms, surface proteins were prepared using a novel trypsin shaving approach and quantified after dimethyl labeling by LC-LTQ/Orbitrap MS. Our data show that some proteins with adhesive functions and others with cell maintenance functions and virulence factor EsxA were significantly upregulated by both treatments. In contrast, immunoglobulin-binding protein A was significantly downregulated for both disinfectants. Significant differences were observed in the effect of the two disinfectants on the expression of surface proteins including some adhesins, foldase protein PrsA, and two virulence factors.

  3. Reactivity of selenium-containing compounds with myeloperoxidase-derived chlorinating oxidants

    DEFF Research Database (Denmark)

    Carroll, Luke; Pattison, David I.; Fu, Shanlin;

    2015-01-01

    Hypochlorous acid (HOCl) and N-chloramines are produced by myeloperoxidase (MPO) as part of the immune response to destroy invading pathogens. However, MPO also plays a detrimental role in inflammatory pathologies, including atherosclerosis, as inappropriate production of oxidants, including HOCl...

  4. One-pot synthesis of new series 3,4,5-trisubstituted-dihydroisoxazoline derivatives via 1,3-dipolar cycloaddition of nitrile oxides with chalcones

    Indian Academy of Sciences (India)

    Raad Kasim Yhya; K M Lokanatha Rai; Ebraheem Abdu Musad

    2013-07-01

    We have synthesized a series of novel isoxazolines via 1,3-dipolar cycloaddition reaction. Aromatic aldoximes undergo oxidative-dehydrogenation with chloramine-T to give nitrile oxides, which were reacted with chalcones to afford of 3,4,5-trisubstituted 4,5-dihydroisoxazolines in a good yield.

  5. Hydrogen peroxide as pre-treatment stressor in experimental immer-sion challenge of rainbow trout fry with Flavobacterium psychrophilum

    DEFF Research Database (Denmark)

    Henriksen, Maya Maria Mihályi; Madsen, Lone; Dalsgaard, Inger

    2012-01-01

    . Non-medical therapeutic substances are routinely used against pathogens in aquacultures, including copper sulphate, chloramine-T, sodium carbonates, sodium chloride, formalin and hydrogen peroxide (H2O2). One of the more successful immersion models used formalin as a stressor, but a less harmful...

  6. Whole-Genome Sequences of Four Strains Closely Related to Members of the Mycobacterium chelonae Group, Isolated from Biofilms in a Drinking Water Distribution System Simulator

    Science.gov (United States)

    We report the draft genome sequences of four Mycobacterium chelonae group strains from biofilms obtained after a ‘chlorine burn’ in a chloraminated drinking water distribution system simulator. These opportunistic pathogens have been detected in drinking and hospital water distr...

  7. [Endodontic microbiology: antimicrobial canal medications].

    Science.gov (United States)

    Seltzer, S; Farber, P A

    1989-06-01

    Medicaments used for reducing or eliminating microorganisms from infected root canals include: irrigating solutions, such as sodium hypochlorite, urea peroxide and hydrogen peroxide, chloramine, iodine-potassium-iodide solution, and chlorhexidine solution. In addition, various intracanal drugs, such as calcium hydroxide and antibiotics, are in use. The characteristics of these drugs are discussed.

  8. 40 CFR 141.624 - Additional requirements for consecutive systems.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Stage 2 Disinfection... system that does not add a disinfectant but delivers water that has been treated with a primary or... requirements for chlorine and chloramines in § 141.131 (c) and § 141.132(c)(1) and the compliance...

  9. The dinoflagellates Pfiesteria shumwayae and Luciella masanensis cause fish kills in recirculation fish farms in Denmark

    DEFF Research Database (Denmark)

    Moestrup, Øjvind; Hansen, Gert; Daugbjerg, Niels;

    2014-01-01

    are apparently the first RAS farms in which serious fish kills have been reported. In the marine farm (Luciella) fish mortality increased dramatically despite treatment of the water with peracetic acid and chloramine-T. The plant was temporarily closed down pending investigation into the cause of mortality...

  10. Linking water treatment practices and fish welfare

    DEFF Research Database (Denmark)

    Zubiaurre, Claire; Pedersen, Lars-Flemming

    2016-01-01

    Peracetic acids can be used as sanitizers to control water quality in aquaculture systems. As an alternative to formalin, chloramine-T or copper sulphate, PAA has strong anti-microbial effects, degrades quickly and is relatively safe to use. Its mode of action and associated rapid decay can make...

  11. TRIBROMOPYRROLE, BROMINATED ACIDS, AND OTHER DISINFECTION BYPRODUCTS PRODUCED BY DISINFECTION OF DRINKING WATER RICH IN BROMIDE

    Science.gov (United States)

    Using gas chromatography/mass spectrometry (GC/MS), we investigated the formation of disinfection byproducts (DBPs) from high bromide waters (2 mg/L) treated with chlorine or chlorine dioxide used in combination with chlorine and chloramines. This study represents the first comp...

  12. Genotoxicity of Disinfection By-products: Comparison to Carcinogenicity

    Science.gov (United States)

    Disinfection by-products (DBPs) can be formed when water is disinfected by various agents such as chlorine, ozone, or chloramines. Among the >600 DBPs identified in drinking water, 11 are regulated by the U.S. Environmental Protection Agency, and another ~70 DBPs that occur at s...

  13. Treatment of trichodiniasis in eel ( Anguilla anguilla ) reared in recirculation systems in Denmark : alternatives to formaldehyde

    DEFF Research Database (Denmark)

    Madsen, H.C.K.; Buchmann, Kurt; Mellergaard, Stig

    2000-01-01

    parasiticidal effect: acriflavin (25 ppm), bithionol (0.1 ppm), chloramine T (50 ppm), Detarox AP(R) (45 ppm), malachite green (1 ppm), raw garlic (200 ppm), potassium permanganate (20 ppm) and Virkon PF(R) vet. (20 ppm). Preliminary screening revealed that the anthelmintic, bithionol, and the decomposable...

  14. Synthesis and radioiodination of analogues of substance P for the building up of a radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Bienert, M.; Schmidt, H.E.; Ehrlich, A.; Forner, K.; Klauschenz, E.; Furkert, J.; Rathsack, R.; Niedrich, H. (Akademie der Wissenschaften der DDR, Berlin. Inst. fuer Wirkstofforschung; Akademie der Wissenschaften der DDR, Berlin-Buch. Zentralinstitut fuer Isotopen- und Strahlenforschung)

    1984-02-01

    The substance P (SP) analogs (Lys(MSOC)/sup 3/)-SP, (Tyr/sup 8/)-SP, (Tyr/sup 8/,Nle/sup 11/)-SP and (p-HPA/sup 1/)-SP have been synthesized by classical methods of peptide synthesis as well as by the liquid phase peptide synthesis (LPPS) to allow conjugation with protein in the N..cap alpha..-position and radioiodination. (Tyr/sup 8/)-SP and (p-HPA-Arg/sup 1/)-SP have been radioiodinated by the chloramine T- and the lactoperoxidase method. A complete S-oxidation of SP was observed, when the chloramine T procedure was used, but this modification does not disturb the assay. The introduction of the (/sup 125/I-pHPA-Arg/sup 1/)-SP-tracer led to considerable improvements of our SP-radioimmunoassay.

  15. Laboratory investigations on the effect of selected disinfectants on survival of the cockroaches Blattella germanica (L.).

    Science.gov (United States)

    Racewicz, M

    1983-01-01

    It was ascertained that lysol 2% and 5% showed the most toxic effect in control of cockroaches in the contact method (23.3% and 95.5% mortality after 24 hours of exposure), and that chloramine 1%, 3% and 5% was the most effective food poison (after 19 days exposure 100% of the insects died). When injecting disinfectant into the body cavity, the cockroaches showed a ten times higher sensibility to formalin and chloramine than to lysol. The use, however, of disinfectant in the contact method (particularly lysol 2%) together with an insecticide based on propoxur, allowed to reduce its dose to a half, what gave better results than the use of an insecticide alone in a normal dose.

  16. Kinetics and Mechanism of Electron Transfer Reaction: Oxidation of Sulfanilic Acid by N-Chloro-p-Toluene Sulfonamide in Acid Perchlorate Medium

    Energy Technology Data Exchange (ETDEWEB)

    Sailani, Riya; Bhasin, Meneka; Khandelwal, C. L.; Sharma, P. D. [Univ. of Rajasthan, Jaipur (India)

    2014-01-15

    The kinetics and mechanism of oxidation of sulfanilic acid by N-chloro-p-toluene sulfonamide (chloramine-T) have been studied in acid medium. The species of chloramine-T were analysed on the basis of experimental observations and predominantly reactive species was taken into account for proposition of most plausible reaction mechanism. The derived rate law (1) conforms to such a mechanism. All kinetic parameters were evaluated. Activation parameters such as energy and entropy of activation were calculated to be (61.67 ± 0.47) kJ mol{sup -1} and (-62.71 ± 2.48) JK{sup -1}mol{sup -1} respectively employing Eyring equation.

  17. Relative importance of N-nitrosodimethylamine compared to total N-nitrosamines in drinking waters.

    Science.gov (United States)

    Dai, Ning; Mitch, William A

    2013-04-16

    A U.S.-wide occurrence survey conducted as part of the Unregulated Contaminant Monitoring Rule 2 found that N-nitrosodimethylamine (NDMA) was present in 34% of chloraminated drinking water samples but was the most prevalent of the six N-nitrosamines evaluated using U.S. Environmental Protection Agency (EPA) Method 521. If the U.S. EPA considers limiting exposures to N-nitrosamines as a group, a critical question is whether NDMA is the most prevalent N-nitrosamine or whether significant concentrations occur for N-nitrosamines other than those captured by EPA Method 521. A total N-nitrosamine assay was developed and applied to 36 drinking water plant effluents or distribution system samples from 11 utilities, including 9 utilities that practiced chloramination for secondary disinfection. Concurrent application of EPA Method 521 indicated that NDMA was the most prevalent of the Method 521 N-nitrosamines yet accounted for ∼5% of the total N-nitrosamine pool on a median basis. Among eight plant influent waters, NDMA was detected once, while total N-nitrosamines were detected in five samples, suggesting the importance of source water protection. Similar to NDMA, total N-nitrosamine concentrations in source waters increased after chloramination. Chloramines were applied to organic precursors serving as models for pristine natural organic matter, algal exudate, wastewater effluent, and polyDADMAC quaternary amine-based coagulation polymers. While high yields of NDMA were restricted to the wastewater effluent and polyDADMAC, high yields of total N-nitrosamines were observed from the algal exudate, the wastewater effluent, and polyDADMAC. The results suggest that N-nitrosamines as a class may be more prevalent than suggested by occurrence surveys conducted using EPA Method 521.

  18. [Some properties of plasmocoagulase of the causative agents of glanders and melioidosis].

    Science.gov (United States)

    Narbutovich, N I; Lomova, L V; Ageeva, N P; Kucheriaeva, V T; Seimova, I K

    2005-01-01

    Criteria for the evaluation of the plasmocoagulase activity of natural isolates and mutant strains of the causative agents of glanders and melioidosis were worked out, which made it possible to subdivide them by this sign into pathogens with high, moderate and low activity. Plasmocoagulase produced by pathogenic Burkholderia was shown to be a thermolabile enzyme, comparatively stable with respect to the action of such chemico-biological agents as hydrogen peroxide and chloramine.

  19. New aquaculture drugs under FDA review

    Science.gov (United States)

    Bowker, James D.; Gaikowski, Mark P.

    2012-01-01

    Only eight active pharmaceutical ingredients available in 18 drug products have been approved by the U.S. Food and Drug Administration for use in aquaculture. The approval process can be lengthy and expensive, but several new drugs and label claims are under review. Progress has been made on approvals for Halamid (chloramine-T), Aquaflor (florfenicol) and 35% PeroxAid (hydrogen peroxide) as therapeutic drugs. Data are also being generated for AQUI-S 20E, a fish sedative.

  20. Strontium Adsorption and Desorption Reactions in Model Drinking Water Distribution Systems

    Science.gov (United States)

    2014-02-04

    Strontium K-edge spectra for bulk XANES sr’+ standards and for the iron corrosion product samples representing (a) chlorine and chloramine simulated...RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) 11-04-2014 Journal Article Strontium adsorption and desorption reactions in model... strontium (Sr2+) adsorption to and desorption from iron corrosion products were examined in two model drinking water distribution systems (DWDS

  1. Changes in the Expression of Biofilm-Associated Surface Proteins in Staphylococcus aureus Food-Environmental Isolates Subjected to Sublethal Concentrations of Disinfectants

    Directory of Open Access Journals (Sweden)

    Lenka Cincarova

    2016-01-01

    Full Text Available Sublethal concentrations (sub-MICs of certain disinfectants are no longer effective in removing biofilms from abiotic surfaces and can even promote the formation of biofilms. Bacterial cells can probably adapt to these low concentrations of disinfectants and defend themselves by way of biofilm formation. In this paper, we report on three Staphylococcus aureus biofilm formers (strong B+++, moderate B++, and weak B+ that were cultivated with sub-MICs of commonly used disinfectants, ethanol or chloramine T, and quantified using Syto9 green fluorogenic nucleic acid stain. We demonstrate that 1.25–2.5% ethanol and 2500 μg/mL chloramine T significantly enhanced S. aureus biofilm formation. To visualize differences in biofilm compactness between S. aureus biofilms in control medium, 1.25% ethanol, or 2500 μg/mL chloramine T, scanning electron microscopy was used. To describe changes in abundance of surface-exposed proteins in ethanol- or chloramine T-treated biofilms, surface proteins were prepared using a novel trypsin shaving approach and quantified after dimethyl labeling by LC-LTQ/Orbitrap MS. Our data show that some proteins with adhesive functions and others with cell maintenance functions and virulence factor EsxA were significantly upregulated by both treatments. In contrast, immunoglobulin-binding protein A was significantly downregulated for both disinfectants. Significant differences were observed in the effect of the two disinfectants on the expression of surface proteins including some adhesins, foldase protein PrsA, and two virulence factors.

  2. Synthesis of iodobuprenorphine for use in radioimmunoassay. [Analgesic

    Energy Technology Data Exchange (ETDEWEB)

    Debrabandere, L.; Boven, M. van; Daenens, P. (Leuven Univ. (Belgium). Lab. of Toxicology)

    1992-08-01

    The synthesis of [[sup 125]I]iodobuprenorphine is described. This compound has been used as a tracer molecule in the development of a new radioimmunoassay for buprenorphine. The parameters that effect the direct iodination of buprenorphine using sodium [[sup 127]I]iodide, in the presence of either chloramine-T or Iodo-Beads, were studied. The structure of iodobuprenorphine was confirmed by mass spectrometry. (author).

  3. Peracetic acid products expand sanitizing, organic water treatment options

    OpenAIRE

    Pedersen, Lars-Flemming; Jokumsen, Alfred; Larsen, Villy J.; Henriksen, Niels Henrik

    2015-01-01

    Peracetic acids can be used as sanitizers to control water quality in aquaculture systems. As an alternative to formalin, chloramine-T or copper sulphate, PAA has strong anti-microbial effects, degrades quickly and is relatively safe to use. Its mode of action and associated rapid decay can make optimizing treatment protocols a challenge. Continuous low-dose applications seem to be a promising solution. PAA is among the few disinfectants approved for organic aquaculture

  4. [Tests on the bactericidal effectiveness of iodophor A in the halls of a pig-fattening station].

    Science.gov (United States)

    Kubícek, K

    1975-04-01

    In the halls of the pig fattening house the bactericidal effectiveness of cold water solutions of Czechoslovakia-made Jodofor A and the product of the Ciba-Geigy company Iosan was tested and compared with the effectiveness of Chloramin B used in a water solution at the temperature of 50 to 60 degrees C. The solutions were applied by fine spraying at the rate of 0.5 lt. per 1 m2 of area. After one hour the spray was applied again at the same rate. One hour after the last Jodofor spray and two hours after the last Chloramin B spray, smears were collected from the disinfected surfaces. The examination included the detection of coliform germs, germs of the Micrococcaceae family, and the determination of the total number of germs. On the whole, 384 smears were examined in four separate trials. The application of Jodofor A in 2% concentrations, after mechanical average-quality purification, did not give acceptable results, in comparison with the solution of Cloramin B. Only when solutions of Jodofor A and Iosan were used in 3% concentration after perfect mechanical purification, satisfactory results were obtained (with the exception of plaster and painted wood), in comparison with the Chloramin B solution. Better disinfectibility was found in aluminium sheet, terracotta, concrete, and metal, as distinct from plaster and painted wood. The comparison of Jodofor A with abroad-male Iosan indicates that Jodofor has the same or a better bactericidal effect than Iosan in all indices. Due to its bactericidal effect, Jodofor A is a suitable disinfectant for preventive disinfection of farm animal houses. In order to achieve results corresponding to those provided by 2% solutions of Chloramin B it is necessary to use at least 3% concentration of Jodofor A. Good mechanical purification is a basic prerequisite for its effectiveness.

  5. Veterinary antibiotics used in animal agriculture as NDMA precursors.

    Science.gov (United States)

    Leavey-Roback, Shannon L; Krasner, Stuart W; Suffet, Irwin Mel H

    2016-12-01

    The formation of carcinogenic N-nitrosodimethylamine (NDMA) during chloramination at drinking water treatment plants has raised concerns as more plants have switched from chlorine to chloramine disinfection. In this study, a source of NDMA precursors that has yet to be investigated was examined. Veterinary antibiotics are used in large quantities at animal agricultural operations. They may contaminate drinking water sources and may not be removed during wastewater and drinking water treatment. Ten antibiotics used in animal agriculture were shown to produce NDMA or N-nitrosodiethylamine (NDEA) during chloramination. Molar conversions ranged from 0.04 to 4.9 percent, with antibiotics containing more than one dimethylamine (DMA) functional group forming significantly more NDMA. The highest formation for most of the compounds was seen near pH 8.4, in a range of pH 6 to 11 that was investigated. The effect of chlorine-to-ammonia ratio (Cl2/NH3), temperature, and hold time varied for each chemical, suggesting that the effects of these parameters were compound-specific.

  6. Study by XPS of the chlorination of proteins aggregated onto tin dioxide during electrochemical production of hypochlorous acid

    Energy Technology Data Exchange (ETDEWEB)

    Debiemme-Chouvy, Catherine [Laboratoire Interfaces et Systemes Electrochimiques, UPR 15 du CNRS, UPMC Case Courrier 133-4, Place Jussieu, 75252 Paris Cedex (France)]. E-mail: debiemme@ccr.jussieu.fr; Haskouri, Sanae [Laboratoire Interfaces et Systemes Electrochimiques, UPR 15 du CNRS, UPMC Case Courrier 133-4, Place Jussieu, 75252 Paris Cedex (France); Cachet, Hubert [Laboratoire Interfaces et Systemes Electrochimiques, UPR 15 du CNRS, UPMC Case Courrier 133-4, Place Jussieu, 75252 Paris Cedex (France)

    2007-04-15

    In solution, hypochlorous acid (HOCl) reacts with organic matter and notably with protein side-chains. In this study, HOCl was produced by an electrochemical way, by oxidation of chloride ions at a transparent tin dioxide electrode in the presence of a protein, the bovine serum albumin (BSA). A thick irregular layer is formed at the electrode when HOCl is produced at the SnO{sub 2} surface. Indeed, SEM analyses show that an important deposit is formed during the anodic polarization of SnO{sub 2} in the presence of chloride ions and proteins. Actually, two phenomena take place on the one hand the chlorination of the proteins due to the reaction of HOCl with some protein side-chains and on the other hand the aggregation of proteins onto the SnO{sub 2} surface. The present X-ray photoelectron spectroscopy study points out the cross-linking of BSA molecules via formation of inter molecular sulfonamide groups. It also shows that the BSA chlorination is due on the one hand to the formation of sulfonyl chloride groups (-SO{sub 2}Cl) and on the other hand to formation of chloramine groups ( N-Cl). The Cl2p and S2p photo-peak intensities allowed us to quantify the chloramines. It is found that, one BSA entity immobilized onto the SnO{sub 2} surface contains about 50 chloramine groups.

  7. Antibacterial surface design - Contact kill

    Science.gov (United States)

    Kaur, Rajbir; Liu, Song

    2016-08-01

    Designing antibacterial surfaces has become extremely important to minimize Healthcare Associated Infections which are a major cause of mortality worldwide. A previous biocide-releasing approach is based on leaching of encapsulated biocides such as silver and triclosan which exerts negative impacts on the environment and potentially contributes to the development of bacterial resistance. This drawback of leachable compounds led to the shift of interest towards a more sustainable and environmentally friendly approach: contact-killing surfaces. Biocides that can be bound onto surfaces to give the substrates contact-active antibacterial activity include quaternary ammonium compounds (QACs), quaternary phosphoniums (QPs), carbon nanotubes, antibacterial peptides, and N-chloramines. Among the above, QACs and N-chloramines are the most researched contact-active biocides. We review the engineering of contact-active surfaces using QACs or N-chloramines, the modes of actions as well as the test methods. The charge-density threshold of cationic surfaces for desired antibacterial efficacy and attempts to combine various biocides for the generation of new contact-active surfaces are discussed in detail. Surface positive charge density is identified as a key parameter to define antibacterial efficacy. We expect that this research field will continue to attract more research interest in view of the potential impact of self-disinfective surfaces on healthcare-associated infections, food safety and corrosion/fouling resistance required on industrial surfaces such as oil pipes and ship hulls.

  8. Biostability in distribution systems in one city in southern China: characteristics, modeling and control strategy.

    Science.gov (United States)

    Lu, Pinpin; Zhang, Xiaojian; Zhang, Chiqian; Niu, Zhangbin; Xie, Shuguang; Chen, Chao

    2014-02-01

    This study investigated the bacterial regrowth in drinking water distribution systems receiving finished water from an advanced drinking water treatment plant in one city in southern China. Thirteen nodes in two water supply zones with different aged pipelines were selected to monitor water temperature, dissolved oxygen (DO), chloramine residual, assimilable organic carbon (AOC), and heterotrophic plate counts (HPC). Regression and principal component analyses indicated that HPC had a strong correlation with chloramine residual. Based on Chick-Watson's Law and the Monod equation, biostability curves under different conditions were developed to achieve the goal of HPC residual concentration under the condition of high AOC level. The simulation was also carried out to predict the scenario with a stricter HPC goal (residual. The biological regrowth control strategy was assessed using biostability curve analysis. The results indicated that maintaining high chloramine residual concentration was the most practical way to achieve the goal of HPC < or = 100 CFU/mL. Biostability curves could be a very useful tool for biostability control in distribution systems. This work could provide some new insights towards biostability control in real distribution systems.

  9. Kinetic method for assaying the halogenating activity of myeloperoxidase based on reaction of celestine blue B with taurine halogenamines.

    Science.gov (United States)

    Sokolov, A V; Kostevich, V A; Kozlov, S O; Donskyi, I S; Vlasova, I I; Rudenko, A O; Zakharova, E T; Vasilyev, V B; Panasenko, O M

    2015-06-01

    Myeloperoxidase (MPO) is a challenging molecular target which, if put under control, may allow regulating the development of inflammatory reactions associated with oxidative/halogenative stress. In this paper, a new kinetic method for assaying the halogenating activity of MPO is described. The method is based on measuring the rate of iodide-catalyzed oxidation of celestine blue B (CB) by oxygen and taurine N-chloramine (bromamine). The latter is produced in a reaction of taurine with HOCl (HOBr). CB is not a substrate for the peroxidase activity of MPO and does not react with hydrogen peroxide and superoxide anion radical. Taurine N-chloramine (bromamine) reacts with CB in molar ratio of 1:2. Using the new method, we studied the dependence of MPO activity on concentration of substrates and inhibitors. The specificity of MPO inhibition by non-proteolyzed ceruloplasmin is characterized. The inhibition of taurine N-chloramine production by neutrophils and HL-60 cells in the presence of MPO-affecting substances is demonstrated. The new method allows determining the kinetic parameters of MPO halogenating activity and studying its inhibition by various substances, as well as screening for potential inhibitors of the enzyme.

  10. Assessing microbiological water quality in drinking water distribution systems with disinfectant residual using flow cytometry.

    Science.gov (United States)

    Gillespie, Simon; Lipphaus, Patrick; Green, James; Parsons, Simon; Weir, Paul; Juskowiak, Kes; Jefferson, Bruce; Jarvis, Peter; Nocker, Andreas

    2014-11-15

    Flow cytometry (FCM) as a diagnostic tool for enumeration and characterization of microorganisms is rapidly gaining popularity and is increasingly applied in the water industry. In this study we applied the method to obtain a better understanding of total and intact cell concentrations in three different drinking water distribution systems (one using chlorine and two using chloramines as secondary disinfectants). Chloramine tended to result in lower proportions of intact cells than chlorine over a wider residual range, in agreement with existing knowledge that chloramine suppresses regrowth more efficiently. For chlorinated systems, free chlorine concentrations above 0.5 mg L(-1) were found to be associated with relatively low proportions of intact cells, whereas lower disinfectant levels could result in substantially higher percentages of intact cells. The threshold for chlorinated systems is in good agreement with guidelines from the World Health Organization. The fact that the vast majority of samples failing the regulatory coliform standard also showed elevated proportions of intact cells suggests that this parameter might be useful for evaluating risk of failure. Another interesting parameter for judging the microbiological status of water, the biological regrowth potential, greatly varied among different finished waters providing potential help for investment decisions. For its measurement, a simple method was introduced that can easily be performed by water utilities with FCM capability.

  11. 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)

  12. Detection of Legionella, L. pneumophila and Mycobacterium Avium Complex (MAC along Potable Water Distribution Pipelines

    Directory of Open Access Journals (Sweden)

    Harriet Whiley

    2014-07-01

    Full Text Available Inhalation of potable water presents a potential route of exposure to opportunistic pathogens and hence warrants significant public health concern. This study used qPCR to detect opportunistic pathogens Legionella spp., L. pneumophila and MAC at multiple points along two potable water distribution pipelines. One used chlorine disinfection and the other chloramine disinfection. Samples were collected four times over the year to provide seasonal variation and the chlorine or chloramine residual was measured during collection. Legionella spp., L. pneumophila and MAC were detected in both distribution systems throughout the year and were all detected at a maximum concentration of 103 copies/mL in the chlorine disinfected system and 106, 103 and 104 copies/mL respectively in the chloramine disinfected system. The concentrations of these opportunistic pathogens were primarily controlled throughout the distribution network through the maintenance of disinfection residuals. At a dead-end and when the disinfection residual was not maintained significant (p < 0.05 increases in concentration were observed when compared to the concentration measured closest to the processing plant in the same pipeline and sampling period. Total coliforms were not present in any water sample collected. This study demonstrates the ability of Legionella spp., L. pneumophila and MAC to survive the potable water disinfection process and highlights the need for greater measures to control these organisms along the distribution pipeline and at point of use.

  13. Impact of Nitrification on the Formation of N-Nitrosamines and Halogenated Disinfection Byproducts within Distribution System Storage Facilities.

    Science.gov (United States)

    Zeng, Teng; Mitch, William A

    2016-03-15

    Distribution system storage facilities are a critical, yet often overlooked, component of the urban water infrastructure. This study showed elevated concentrations of N-nitrosodimethylamine (NDMA), total N-nitrosamines (TONO), regulated trihalomethanes (THMs) and haloacetic acids (HAAs), 1,1-dichloropropanone (1,1-DCP), trichloroacetaldehyde (TCAL), haloacetonitriles (HANs), and haloacetamides (HAMs) in waters with ongoing nitrification as compared to non-nitrifying waters in storage facilities within five different chloraminated drinking water distribution systems. The concentrations of NDMA, TONO, HANs, and HAMs in the nitrifying waters further increased upon application of simulated distribution system chloramination. The addition of a nitrifying biofilm sample collected from a nitrifying facility to its non-nitrifying influent water led to increases in N-nitrosamine and halogenated DBP formation, suggesting the release of precursors from nitrifying biofilms. Periodic treatment of two nitrifying facilities with breakpoint chlorination (BPC) temporarily suppressed nitrification and reduced precursor levels for N-nitrosamines, HANs, and HAMs, as reflected by lower concentrations of these DBPs measured after re-establishment of a chloramine residual within the facilities than prior to the BPC treatment. However, BPC promoted the formation of halogenated DBPs while a free chlorine residual was maintained. Strategies that minimize application of free chlorine while preventing nitrification are needed to control DBP precursor release in storage facilities.

  14. Effects of disinfectants in renal dialysis patients

    Energy Technology Data Exchange (ETDEWEB)

    Klein, E.

    1986-11-01

    Patients receiving hemodialysis therapy risk exposure to both disinfectants and sterilants. Dialysis equipment is disinfected periodically with strong solutions of hypochlorite or formaldehyde. Gross hemolysis resulting from accidental hypochlorite infusion has led to cardiac arrest, probably as a result of hyperkalemia. Formaldehyde is commonly used in 4% solutions to sterilize the fluid paths of dialysis controllers and to sterilize dialyzers before reuse. It can react with red cell antigenic surfaces leading to the formation of anti-N antibodies. The major exposure risk is the low concentration of disinfectant found in municipal water used to prepare 450 L dialysate weekly. With thrice-weekly treatment schedules, the quality requirements for water used to make this solution must be met rigorously. Standards for water used in the preparation of dialysate have recently been proposed but not all patients are treated with dialysate meeting such standards. The introduction of sterilants via tap water is insidious and has let to more pervasive consequences. Both chlorine and chloramines, at concentrations found in potable water, are strong oxidants that cause extensive protein denaturation and hemolysis. Oxidation of the Fe/sup 2 +/ in hemoglobin to Fe/sup 3 +/ forms methemoglobin, which is incapable of carrying either O/sub 2/ or CO/sub 2/. Chloramine can form not only methemoglobin, but can also denature proteins within the red cell, thus forming aggregates (Heinz bodies). Chloramines also inhibit hexose monophosphate shunt activity, a mechanism that makes the red cell even more susceptible to oxidant damage.

  15. Occurrence and formation of chloro- and bromo-benzoquinones during drinking water disinfection.

    Science.gov (United States)

    Zhao, Yuli; Anichina, Janna; Lu, Xiufen; Bull, Richard J; Krasner, Stuart W; Hrudey, Steve E; Li, Xing-Fang

    2012-09-15

    Consumption of chlorinated drinking water has shown somewhat consistent association with increased risk of bladder cancer in a series of epidemiological studies, but plausible causative agents have not been identified. Halobenzoquinones (HBQs) have been recently predicted as putative disinfection byproducts (DBPs) that might be of toxicological relevance. This study reports the occurrence frequencies and concentrations of HBQs in plant effluents from nine drinking water treatment plants in the USA and Canada, where four common disinfection methods, chlorination, chloramination, chlorination with chloramination, and ozonation with chloramination, are used. In total, 16 water samples were collected and analyzed for eight HBQs: 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), 2,6-dibromo-1,4-benzoquinone (2,6-DBBQ), 2,6-dichloro-3-methyl-1,4-benzoquinone (2,6-DC-3-MBQ), 2,3,6-trichloro-1,4-benzoquinone (2,3,6-TriCBQ), 2,5-dibromo-1,4-benzoquinone (2,5-DBBQ), 2,3-dibromo-5,6-dimethyl-1,4-benzoquinone (2,3-DB-5,6-DM-BQ), tetrabromo-1,4-benzoquinone (TetraB-1,4-BQ), and tetrabromo-1,2-benzoquinone (TetraB-1,2-BQ). Of these, 2,6-DCBQ, 2,6-DBBQ, 2,6-DC-3-MBQ and 2,3,6-TriCBQ were detected in 16, 11, 6, and 3 of the 16 samples with the method detection limit (DL) of 1.0, 0.5, 0.9 and 1.5 ng/L, respectively, using a solid phase extraction and high performance liquid chromatography-tandem mass spectrometry method. The concentrations were in the ranges of 4.5-274.5 ng/L for 2,6-DCBQ, below DL to 37.9 ng/L for 2,6-DBBQ, below DL to 6.5 ng/L for 2,6-DC-3-MBQ, and below DL to 9.1 ng/L for 2,3,6-TriCBQ. These authentic samples show DCBQ and DBBQ as the most abundant and frequently detectable HBQs. In addition, laboratory controlled experiments were performed to examine the formation of HBQs and their subsequent stability toward hydrolysis when the disinfectants, chlorine, chloramine, or ozone followed by chloramines, reacted with phenol (a known precursor) under various conditions

  16. 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.

  17. Formation and occurrence of new polar iodinated disinfection byproducts in drinking water.

    Science.gov (United States)

    Pan, Yang; Li, Wenbin; An, Hao; Cui, Hao; Wang, Ying

    2016-02-01

    During drinking water disinfection, iodinated disinfection byproducts (I-DBPs) can be generated through reactions between iodide, disinfectants, and natural organic matter. Drinking water I-DBPs have been increasingly attracting attention as emerging organic pollutants as a result of their significantly higher toxicity and growth inhibition than their chloro- and bromo-analogues. In this study, by adopting ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry precursor ion scan, multiple reaction monitoring, and product ion scan analyses, 11 new polar I-DBPs with confirmed structures and eight new polar I-DBPs with proposed structures were detected in simulated drinking water samples. Chloramination of simulated raw waters containing natural organic matter with higher aromaticity produced higher levels of new phenolic I-DBPs. Formation of new polar I-DBPs and total organic iodine (TOI) was most favored in chloramination, followed by chlorine dioxide treatment, and relatively minor in chlorination. Lower pH in chloramination substantially enhanced the formation of new polar I-DBPs and TOI. NH2Cl and dissolved organic nitrogen could be important nitrogen sources and precursors for formation of the two new nitrogenous phenolic I-DBPs. Notably, in tap water samples collected from nine major cities located in the Yangtze River Delta region of China, seven of the 11 new polar I-DBPs with confirmed structures were detected at levels from 0.11 to 28 ng/L, and the two new nitrogenous phenolic I-DBPs were ubiquitous with concentrations from 0.12 to 24 ng/L, likely due to the relatively high dissolved organic nitrogen levels in regional source waters.

  18. Trade-offs in disinfection byproduct formation associated with precursor preoxidation for control of N-nitrosodimethylamine formation.

    Science.gov (United States)

    Shah, Amisha D; Krasner, Stuart W; Lee, Chih Fen Tiffany; von Gunten, Urs; Mitch, William A

    2012-05-01

    Chloramines in drinking water may form N-nitrosodimethylamine (NDMA). Various primary disinfectants can deactivate NDMA precursors prior to chloramination. However, they promote the formation of other byproducts. This study compared the reduction in NDMA formation due to chlorine, ozone, chlorine dioxide, and UV over oxidant exposures relevant to Giardia control coupled with postchloramination under conditions relevant to drinking water practice. Ten waters impacted by treated wastewater, poly(diallyldimethylammonium chloride) (polyDADMAC) polymer, or anion exchange resin were examined. Ozone reduced NDMA formation by 50% at exposures as low as 0.4 mg×min/L. A similar reduction in NDMA formation by chlorination required ∼60 mg×min/L exposure. However, for some waters, chlorination actually increased NDMA formation at lower exposures. Chlorine dioxide typically had limited efficacy regarding NDMA precursor destruction; moreover, it increased NDMA formation in some cases. UV decreased NDMA formation by ∼30% at fluences >500 mJ/cm(2), levels relevant to advanced oxidation. For the selected pretreatment oxidant exposures, concentrations of regulated trihalomethanes, haloacetic acids, bromate, and chlorite typically remained below current regulatory levels. Chloropicrin and trichloroacetaldehyde formation were increased by preozonation or medium pressure UV followed by postchloramination. Among preoxidants, ozone achieved the greatest reduction in NDMA formation at the lowest oxidant exposure associated with each disinfectant. Accordingly, preozonation may inhibit NDMA formation with minimal risk of promotion of other byproducts. Bromide >500 μg/L generally increased NDMA formation during chloramination. Higher temperatures increased NDMA precursor destruction by preoxidants but also increased NDMA formation during postchloramination. The net effect of these opposing trends on NDMA formation was water-specific.

  19. Characteristics of C-, N-DBPs formation from algal organic matter: role of molecular weight fractions and impacts of pre-ozonation.

    Science.gov (United States)

    Zhou, Shiqing; Zhu, Shumin; Shao, Yisheng; Gao, Naiyun

    2015-04-01

    Extracellular organic matter (EOM) and intracellular organic matter (IOM) of Microcystis aeruginosa have been reported to contribute to the formation of carbonaceous disinfection by-products (C-DBPs) and nitrogenous disinfection by-products (N-DBPs). Little is known about DBPs formation from different molecular weight (MW) fractions, especially for N-nitrosodimethylamine (NDMA). This study fractionated EOM and IOM into several MW fractions using a series of ultrafiltration membranes and is the first to report on the C-DBPs and N-DBPs formation from chlorination and chloramination of different MW fractions. Results showed that EOM and IOM were mainly distributed in low-MW (100 KDa) fractions. Additionally, the low-MW and high-MW fractions of EOM and IOM generally took an important part in forming C-DBPs and N-DBPs, either in chlorination or in chloramination. Furthermore, the effects of pre-ozonation on the formation of DBPs in subsequent chlorination and chloramination were also investigated. It was found that ozone shifted the high-MW fractions of EOM and IOM into lower MW fractions and increased the C-DBPs and N-DBPs yields to different degrees. As low-MW fractions are more difficult to remove than high-MW fractions by conventional treatment processes, therefore, activated carbon adsorption, nanofiltration (NF) and biological treatment processes can be ideal to remove the low-MW fractions and minimize the formation potential of C-DBPs and N-DBPs. Moreover, the use of ozone should be carefully considered in the treatment of algal-rich water.

  20. Assays for calcitonin receptors

    Energy Technology Data Exchange (ETDEWEB)

    Teitelbaum, A.P.; Nissenson, R.A.; Arnaud, C.D.

    1985-01-01

    The assays for calcitonin receptors described focus on their use in the study of the well-established target organs for calcitonin, bone and kidney. The radioligand used in virtually all calcitonin binding studies is /sup 125/I-labelled salmon calcitonin. The lack of methionine residues in this peptide permits the use of chloramine-T for the iodination reaction. Binding assays are described for intact bone, skeletal plasma membranes, renal plasma membranes, and primary kidney cell cultures of rats. Studies on calcitonin metabolism in laboratory animals and regulation of calcitonin receptors are reviewed.

  1. An Evaluation of the Eclox Chemiluminescence Test, Hach Pesticide/Nerve Agent Test Strips, and Agri-Screen Test Tickets

    Science.gov (United States)

    2010-06-30

    communication), so stock solutions were titrated with 1N HCl or 1N NaOH until their pH was in the suitable Eclox testing range (pH 6-8). 3. Results... titrating pentachlorophenol in 50 millimolar (mM) phosphate buffer with 1 molar hydrochloric acid to pH 7.5. Test chemicals were used either the...Chromatograph Sigma-Aldrich >14 days 99.5 Chloramine [monochloramine] 10599-90-3 4º C / dark amperometric titration Sigma-Aldrich 24 hrs NA

  2. An Evaluation of the NIDS (registered trademark) ACE (trademark) Test

    Science.gov (United States)

    2014-06-30

    included chemicals commonly used for drinking water disinfection (chlorine and chloramine), byproducts of cyanobacteria blooms (geosmin and 2...traceable thermometer. Test results at different operational temperatures are found in Section 3.3.4. - This space ...reagent) with the ACE™ Test - This space intentionally left blank - 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 0 2 4 6 8 10 12 14 16 H

  3. Operation, Maintenance and Performance Evaluation of the Potomac Estuary Experimental Water Treatment Plant. Main Volume.

    Science.gov (United States)

    1983-09-01

    Gravity Filtration and Filtered Water Clearwell 11-4-6 Granular Activated Carbon Adsorption 11-4-6 GAC Regeneration 11-4-7 Ozonation 11-4-7 -14- ,o 4...Table of Contents Page Chloramination 11-4-7 Finished Water Clearwell , Washwater Storage and Pumping 11-4-7 Solids Handling and Disposal...from a 7,750 ft3 clearwell located below and adjacent to the gravity filter structure. This clearwell also served as a reservoir for GAC feedwater. The

  4. Preparation of iodine-123 labeled AM251: a potential SPECT radioligand for the brain cannabinoid CB1 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Ruoxi; Makriyannis, Alexandros [Connecticut Univ., Molecular and Cell Biology Dept., Storrs, CT (United States); Gatley, S.J. [Brookhaven National Lab., Medical Dept., Upton, NY (United States)

    1996-10-01

    We report the synthesis and labeling with iodine-123 of N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251). This compound is an analog of the recently described cannabinoid receptor antagonist, SR141716A, in which a 4-chlorophenyl group is replaced by 4-iodophenyl. Labeling in good yield (62%) and radiochemical purity (> 95%), and high specific activity (> 2500 Ci/mmol) was achieved by an iododestannylation reaction using the tributyltin precursor, no carrier added I-123 iodide, and chloramine-T. (author).

  5. Synthesis of new series of 5,6-dihydro-4H-1,2-oxazines via hetero Diels-Alder reaction and evaluation of antimicrobial activity.

    Science.gov (United States)

    Manjula, M K; Rai, K M L; Gaonkar, S L; Raveesha, K A; Satish, S

    2009-01-01

    A new series of 5,6-dihydro-4H-1,2-oxazines were synthesized via hetero Diels-Alder reaction of alpha-nitrosoolefins with alkenes. alpha-Nitrosoolefins were generated from ketoximes by the action of chloramine-T. The newly synthesized compounds were characterized with IR, NMR, elemental analysis and screened for their antimicrobial activity; they exhibited excellent antimicrobial activity. The minimal inhibitory concentration of the compounds was in the range of 10-35 microg ml(-1) for bacteria and 10-40 microg ml(-1) for fungi.

  6. Synthesis and in vitro assessment of antifungal activity of oximes, oxime ethers and isoxazoles.

    OpenAIRE

    Diaz-Velandia, John; Laboratorio de síntesis orgánica, Departamento de Química. Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia.; Durán-Díaz, Natalia; Laboratorio de síntesis orgánica, Departamento de Química. Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia.; Robles-Camargo, Jorge; Laboratorio de síntesis orgánica, Departamento de Química. Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia.; Loaiza, Alix Elena; Laboratorio de síntesis orgánica, Departamento de Química. Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia

    2011-01-01

    Objective. To synthesize and carry out a preliminary evaluation of the in vitro antifungal activity of oximes, oxime ethers and isoxazoles. Materials and methods. Oximes were synthesized from aldehydes or ketones with NH2OH.HCl and K2CO3. Oxime ethers were prepared by alkylation of oximes with propargyl bromide or 2-bromobenzyl bromide, using NaOH as base and acetone as solvent. The isoxazoles were obtained by 1,3-dipolar cycloadditions using ceric ammonium nitrate (CAN), chloramine T (CA...

  7. Bioanalytical and chemical assessment of the disinfection by-product formation potential: role of organic matter.

    Science.gov (United States)

    Farré, Maria José; Day, Sophie; Neale, Peta A; Stalter, Daniel; Tang, Janet Y M; Escher, Beate I

    2013-09-15

    Disinfection by-products (DBP) formed from natural organic matter and disinfectants like chlorine and chloramine may cause adverse health effects. Here, we evaluate how the quantity and quality of natural organic matter and other precursors influence the formation of DBPs during chlorination and chloramination using a comprehensive approach including chemical analysis of regulated and emerging DBPs, total organic halogen quantification, organic matter characterisation and bioanalytical tools. In vitro bioassays allow us to assess the hazard potential of DBPs early in the chain of cellular events, when the DBPs react with their molecular target(s) and activate stress response and defence mechanisms. Given the reactive properties of known DBPs, a suite of bioassays targeting reactive modes of toxic action including genotoxicity and sensitive early warning endpoints such as protein damage and oxidative stress were evaluated in addition to cytotoxicity. Coagulated surface water was collected from three different drinking water treatment plants, along with reverse osmosis permeate from a desalination plant, and DBP formation potential was assessed after chlorination and chloramination. While effects were low or below the limit of detection before disinfection, the observed effects and DBP levels increased after disinfection and were generally higher after chlorination than after chloramination, indicating that chlorination forms higher concentrations of DBPs or more potent DBPs in the studied waters. Bacterial cytotoxicity, assessed using the bioluminescence inhibition assay, and induction of the oxidative stress response were the most sensitive endpoints, followed by genotoxicity. Source waters with higher dissolved organic carbon levels induced increased DBP formation and caused greater effects in the endpoints related to DNA damage repair, glutathione conjugation/protein damage and the Nrf2 oxidative stress response pathway after disinfection. Fractionation studies

  8. Labelling of ochratoxins with sup 3 H or sup 125 I

    Energy Technology Data Exchange (ETDEWEB)

    Schmiedova, D.; Veres, K.; Cerny, B. (Ceskoslovenska Akademie Ved, Prague (Czechoslovakia). Ustav Nuklearni Biologie a Radiochemie); Ruprich, J. (Institut Hygieny a Epidemiologie, Prague (Czechoslovakia)); Nemecek, J. (Slovak Academy of Sciences, Prague (Czechoslovakia). Inst. of Microbiology)

    1989-01-01

    Catalytic hydrogenation of ochratoxin A by carrier-free tritium was used to prepare {sup 3}H-ochratoxin B with a high specific activity. Iodination of ochratoxin B by carrier-free Na {sup 125}I using the chloramine method yielded {sup 125}I-ochratoxin with a high specific activity. Another {sup 125}I-derivative of ochratoxin A was prepared by iodination of an ochratoxin A - L-tyrosine-methylester conjugate. All three radioactive preparations were found to be useful for radioimmunoassay. (author).

  9. [Most frequent causes of allergic contact dermatitis in farmers: based on material collected in the Nofer Institute of Occupational Medicine, Lodz].

    Science.gov (United States)

    Kieć-Swierczyńska, Marta; Krecisz, Beata; Swierczyńska-Machura, Dominika

    2003-01-01

    Farmers are exposed to many skin damaging factors. Following dermatological and allergological examinations, in a group of 132 farmers with suspected occupational disease, contact allergy induced by metals (chromates, nickel, cobalt, mercury), disinfectants and their components (formaldehyde, glutaraldehyde, quaternary ammonium compounds, lysol, chloramine), rubber and pesticides, especially pesticides of thiophtalimide and thiocarbamate groups were recorded. Farmers also reacted to other chemical compounds (colophony, lanolin, propolis) rarely responsible for hypersensitivity in other occupational groups. In addition, extensive areas of dermatitis (13%) induced by irritating chemical (fertilizers, pesticides, fodder for breeding animals) and physical (changing temperature, humidity, effect of solar radiation) factors were observed in the study group.

  10. [Disinfectants in health service institutions and frequency of their use].

    Science.gov (United States)

    Kieć-Swierczyńska, M

    1995-01-01

    On the basis of information obtained from sanitary and epidemiological stations places all over the country and from hospitals of the Lodz region it was found that about 60 types of disinfectants are now under use in Poland. The most frequent ones are: lysoformine, chloramine, aldesan, virkon, hypochloride, septil R, cidex, lysol, denatured alcohol, secuspet, aerodesine 2000, desoform, iodoseptane. Some of them contain well known allergenic factors (glutaraldehyde, benzalkonium, hydroquinone, phenol). Bearing in mind an increasing incidence of occupational skin diseases among health service workers it is postulated to continue studies of allergenic properties of disinfectants.

  11. Fungicidal effect of 15 disinfectants against 24 fungal contaminants commonly found in bread and cheese manufacturing

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, Kirsten; Nielsen, Per Væggemose

    1996-01-01

    .0 % formaldehyde, 0.1 % potassium hydroxide, 3.0 % hydrogen peroxide or 0.3 % peracetic acid were ineffective as fungicides. The fungicidal effect of quaternary ammonium compounds and chlorine compounds showed great variance between species and among the 6 tested isolates of Penicillium roqueforti var. roqueforti......Resistance of 19 mold- and 6 yeast- species against 15 commercial disinfectants was investigated by a suspension-method in which the fungicidal effect and germination time were determined at 20 °C. Disinfectants containing 0.5 % dodecyldiethylentriaminacetic acid, 10 g/l chloramine-T, 2...

  12. Methods to eradicate soft tunic syndrome (STS)-causing protozoa Azumiobodo hoyamushi, the highly infectious parasite from the edible ascidian (Halocynthia roretzi)

    OpenAIRE

    Ji-Hoon Lee; Jae-Geun Lee; Seung-Ryul Zeon; Kyung-Il Park; Kwan Ha Park

    2016-01-01

    Abstract Although soft tunic syndrome (STS) in the ascidian is a serious disease, helpful measures have yet not been established. It was examined in this study by applying aniti-parasitic drugs to eradicate the causative protozoa Azumiobodo hoyamushi from infected ascidians. Formalin was synergistic in killing parasites in vitro when co-treated with hydrogen peroxide (H2O2) or bronopol, but not with chloramine-T or povidone-iodine (PVP-I), when tested with in vitro parasite culture. The syner...

  13. Comparison of specific radioactivities of human alpha-lactalbumin iodinated by three different methods

    Energy Technology Data Exchange (ETDEWEB)

    Thean, E.T. ( Monash Medical School, Prahran, Victoria (Australia))

    1990-08-01

    Radioiodination provides an extremely sensitive method for the detection of low levels of proteins. In the development of a sensitive radioimmunoassay for human alpha-lactalbumin (alpha-LA), the protein was labeled to high specific activity (approaching 2000 Ci/mmol) with lactoperoxidase, chloramine-T, and Iodogen. Despite high specific activities of the labeled protein by each method, there was a considerable difference in their binding affinity with monoclonal anti-human alpha-LA antibodies due to varying degrees of protein damage. Iodination of human alpha-LA with Iodogen resulted in labels of the highest specific activity and immunoreactivity with the monoclonal antibodies used.

  14. Rapid and efficient radiosynthesis of [{sup 123}I]I-PK11195, a single photon emission computed tomography tracer for peripheral benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Pimlott, Sally L. [Department of Clinical Physics, West of Scotland Radionuclide Dispensary, Western Infirmary, G11 6NT Glasgow (United Kingdom)], E-mail: s.pimlott@clinmed.gla.ac.uk; Stevenson, Louise [Department of Chemistry, WestCHEM, University of Glasgow, G12 8QQ Glasgow (United Kingdom); Wyper, David J. [Institute of Neurological Sciences, Southern General Hospital, G51 4TF Glasgow (United Kingdom); Sutherland, Andrew [Department of Chemistry, WestCHEM, University of Glasgow, G12 8QQ Glasgow (United Kingdom)

    2008-07-15

    Introduction: [{sup 123}I]I-PK11195 is a high-affinity single photon emission computed tomography radiotracer for peripheral benzodiazepine receptors that has previously been used to measure activated microglia and to assess neuroinflammation in the living human brain. This study investigates the radiosynthesis of [{sup 123}I]I-PK11195 in order to develop a rapid and efficient method that obtains [{sup 123}I]I-PK11195 with a high specific activity for in vivo animal and human imaging studies. Methods: The synthesis of [{sup 123}I]I-PK11195 was evaluated using a solid-state interhalogen exchange method and an electrophilic iododestannylation method, where bromine and trimethylstannyl derivatives were used as precursors, respectively. In the electrophilic iododestannylation method, the oxidants peracetic acid and chloramine-T were both investigated. Results: Electrophilic iododestannylation produced [{sup 123}I]I-PK11195 with a higher isolated radiochemical yield and a higher specific activity than achievable using the halogen exchange method investigated. Using chloramine-T as oxidant provided a rapid and efficient method of choice for the synthesis of [{sup 123}I]I-PK11195. Conclusions: [{sup 123}I]I-PK11195 has been successfully synthesized via a rapid and efficient electrophilic iododestannylation method, producing [{sup 123}I]I-PK11195 with a higher isolated radiochemical yield and a higher specific activity than previously achieved.

  15. Two in-vivo protocols for testing virucidal efficacy of handwashing and hand disinfection.

    Science.gov (United States)

    Steinmann, J; Nehrkorn, R; Meyer, A; Becker, K

    1995-01-01

    Whole-hands and fingerpads of seven volunteers were contaminated with poliovirus type 1 Sabin strain in order to evaluate virucidal efficacy of different forms of handwashing and handrub with alcohols and alcohol-based disinfectants. In the whole-hand protocol, handwashing with unmedicated soap for 5 min and handrubbing with 80% ethanol yielded a log reduction factor (RF) of > 2, whereas the log RF by 96.8% ethanol exceeded 3.2. With the fingerpad model ethanol produced a greater log RF than iso- or n-propanol. Comparing five commercial hand disinfectants and a chlorine solution (1.0% chloramine T-solution) for handrub, Desderman and Promanum, both composed of ethanol, yielded log RFs of 2.47 and 2.26 respectively after an application time of 60 s, similar to 1.0% chloramine T-solution (log RF of 2.28). Autosept, Mucasept, and Sterillium, based on n-propanol and/or isopropanol, were found to be significantly less effective (log RFs of 1.16, 1.06 and 1.52 respectively). A comparison of a modified whole-hand and the fingerpad protocol with Promanum showed similar results with the two systems suggesting both models are suitable for testing the in-vivo efficacy of handwashing agents and hand disinfectants which are used without any water.

  16. Hypochlorite-induced oxidation of proteins in plasma

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    1999-01-01

    Activated phagocyte cells generate hypochlorite (HOCl) via the release of H2O2 and the enzyme myeloperoxidase. Plasma proteins are major targets for HOCl, although little information is available about the mechanism(s) of oxidation. In this study the reaction of HOCl (at least 50 microM) with dil......Activated phagocyte cells generate hypochlorite (HOCl) via the release of H2O2 and the enzyme myeloperoxidase. Plasma proteins are major targets for HOCl, although little information is available about the mechanism(s) of oxidation. In this study the reaction of HOCl (at least 50 micro......M) with diluted fresh human plasma has been shown to generate material that oxidizes 5-thio-2-nitrobenzoic acid; these oxidants are believed to be chloramines formed from the reaction of HOCl with protein amine groups. Chloramines have also been detected with isolated plasma proteins treated with HOCl. In both...... more efficient. The reaction of fresh diluted plasma with HOCl also gives rise to protein-derived nitrogen-centred radicals in a time- and HOCl-concentration-dependent manner; these have been detected by EPR spin trapping. Identical radicals have been detected with isolated HOCl-treated plasma proteins...

  17. Occurrence of N-nitrosodimethylamine precursors in wastewater treatment plant effluent and their fate during ultrafiltration-reverse osmosis membrane treatment.

    Science.gov (United States)

    Farré, M J; Keller, J; Holling, N; Poussade, Y; Gernjak, W

    2011-01-01

    The formation of N-nitrosodimethylamine (NDMA) is of major concern among wastewater recycling utilities practicing disinfection with chloramines. The NDMA formation potential (FP) test is a simple and straightforward method to evaluate NDMA precursor concentrations in waters. In this paper we show the NDMA FP results of a range of tertiary wastewater treatment plants that are also the source for production of recycled water using an Ultrafiltration - Reverse Osmosis (UF-RO) membrane process. The results indicate that the NDMA FP of different source waters range from 350 to 1020±20 ng/L. The fate of these NDMA precursors was also studied across the different stages of two Advanced Water Treatment Plants (AWTP) producing recycled water. These results show that more than 98.5±0.5% of NDMA precursors are effectively removed by the Reverse Osmosis (RO) membranes used at the AWTPs. This drastically reduces any potential for re-formation of NDMA after the RO stage even if chloramines may be present (or added) there.

  18. Radioiodination and biological evaluation of levalbuterol as a new selective radiotracer. A β{sub 2}-adrenoceptor agonist

    Energy Technology Data Exchange (ETDEWEB)

    Sanad, Mahmoud Hamdi; Abelrahman, Mohamed Abdelmotelb; Marzook, Fawzy Mohamed Abdelmaged [Atomic Energy Authority, Cairo (Egypt). Radioisotopes Production and Radioactive Sources Div.

    2016-08-01

    Levalbuterol was successfully radiolabeled with iodine using chloramine-T as an oxidizing agent via an electrophilic substitution reaction. The reaction parameters that affecting the labeling yield such as levalbuterol concentration, chloramine-T concentration, pH of the reaction medium and reaction time were studied in details. The radiochemical yield was 97.5 ± 0.5% and the radioiodinated compound was separated by HPLC. In vitro studies showed that the iodinated levalbuterol was stable for up to 24 h. The biodistribution in experimental animals showed that the lung uptake was 68.18 ± 0.17% at 5 min post injection which decreased with time until reached to 18.7 ± 0.12% at 2 h which was higher than other recent developed radiopharmaceuticals for lung imaging. The clearance pathways from the mice appear to proceed via both hepatobiliary and renal pathways. Predosing the mice with cold levalbuterol reduced the lung uptake to 20 ± 1.3% and further confirms the high specificity and selectivity of {sup 125}I-levalbuterol for the lung.

  19. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Directory of Open Access Journals (Sweden)

    A. John Blacker

    2015-12-01

    Full Text Available The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates.

  20. Simultaneous Control of Microorganisms and Disinfection By-products by Sequential Chlorination

    Institute of Scientific and Technical Information of China (English)

    CHAO CHEN; XIAO-JIAN ZHANG; WEN-JIE HE; HONG-DA HAN

    2007-01-01

    Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out in a drinking water plant. Results The sequential chlorination disinfection process had the same or better efficiency on microbe (including virus)inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process.The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination.Conclusion This process takes advantages of free chlorine's quick inactivation of microorganisms and chloramine's low disinfection by-product (DBP) yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.

  1. Occurrence of halogenated furanones in U.S. drinking waters.

    Science.gov (United States)

    Onstad, Gretchen D; Weinberg, Howard S; Krasner, Stuart W

    2008-05-01

    Chlorinated and brominated forms of MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) were detected in the disinfected waters of six pairs of U.S. drinking watertreatment plants, with MX as high as approximately 310 ng/L in finished water. The strength of this study is in its comparison between pairs of plants that drew water from the same or similar watersheds and treated the raw source water with two contrasting disinfection and/or treatment schemes. As expected, the brominated MX-analogues were produced in greater abundance than MX from raw source waters with high bromide concentrations. Disinfection of waters with free chlorine produced more MX-analogues than disinfection with monochloramine. Use of chloramines as the residual disinfectant appeared to stabilize MX-analogues once they were formed. Pretreatment with ozone and biologically active granular activated carbon minimized MX-analogue formation upon subsequent chlorination or chloramination, either because MX precursors were altered by ozone, removed by granular activated carbon, or degraded by biological filtration. Pretreatment with chlorine dioxide did not minimize MX-analogue formation. In plant effluent samples, MX and chloroform were positively correlated (molar R = 0.7, N = 6). Similar formation patterns of MX-analogues, trihalomethanes, and haloacetic acids in these water treatment plants suggest that the three classes of disinfection byproduct follow a common formation mechanism from natural organic matter and chlorine.

  2. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Postigo, Cristina [Institute for Environmental Assessment and Water Research (IDAEA)—Spanish National Research Council (CID-CSIC), Barcelona (Spain); Richardson, Susan D., E-mail: richardson.susan@sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC (United States)

    2014-08-30

    Graphical abstract: - Highlights: • Review of transformation pathways of pharmaceuticals during disinfection processes. • DBPs are formed with chlorine, chloramine, ozone, chlorine dioxide, UV, or UV/H{sub 2}O{sub 2}. • Chlorine reacts with amine and reduced sulfur groups and activated aromatic systems. • Chlorine dioxide and ozone react with electron-rich functional groups. • Potential health effects are noted for some pharmacuetical DBPs when available. - Abstract: Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment.

  3. Halonitromethanes formation in wastewater treatment plant effluents.

    Science.gov (United States)

    Song, Hocheol; Addison, Jesse W; Hu, Jia; Karanfil, Tanju

    2010-03-01

    Halonitromethanes (HNMs) constitute one class of emerging disinfection by-products with high potential health risks. This study investigated the formation and occurrence of HNMs under different disinfection scenarios and the presence of their precursors in municipal wastewater treatment plant (WWTPs) effluents. Formation potential tests performed on WWTP effluents revealed that HNM formation occurred in the order of ozonation-chlorination > ozonation-chloramination > chlorination > chloramination. Ozonation alone did not produce any HNM. Municipal WWTP effluents contained some reactive HNM precursors, possibly the by-products of biological treatment processes and/or some moiety of industry or household origin. No effects of nitrate on the formation of HNMs were observed in this study, and nitrification in WWTPs appears to remove appreciable portion of HNM precursors, especially those reactive to chlorine. UV disinfection using low pressure lamps in municipal WWTPs had negligible impact on HNM formation potential. HNM concentrations in the effluents of selected WWTPs were either non-detectable or less than minimum reporting level, except for one WWTP that gave trichloronitromethane concentrations in the range of 0.9-1.5 microg L(-1). No HNMs were observed in the effluents disinfected with UV radiation. Therefore, it appears the typical wastewater disinfection processes involving chlorination or UV treatment in WWTPs do not produce significant amounts of HNMs.

  4. Optimisation of an Advanced Oxidation Protein Products Assay: Its Application to Studies of Oxidative Stress in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Emma L. Taylor

    2015-01-01

    Full Text Available Advanced oxidation protein products (AOPP are reportedly elevated in the plasma of patients with a number of diseases, including diabetes mellitus, that involve oxidative stress. However, the accurate measurement of AOPP in human plasma is hampered by the formation of a precipitate following the addition of potassium iodide and glacial acetic acid according to the published assay procedure. Here we describe a modification of the AOPP assay which eliminates interference by precipitation and provides a robust, reliable, and reproducible protocol for the measurement of iodide oxidising capacity in plasma samples (intra-assay CV 1.7–5.3%, interassay CV 5.3–10.5%. The improved method revealed a significant association of AOPP levels with age (p<0.05 and hypertension (p=0.01 in EDTA-anticoagulated plasma samples from 52 patients with diabetes and 38 nondiabetic control subjects, suggesting a possible link between plasma oxidising capacity and endothelial and/or vascular dysfunction. There was no significant difference between AOPP concentrations in diabetic (74.8 ± 7.2 μM chloramine T equivalents and nondiabetic (75.5 ± 7.0 μM chloramine T equivalents individuals.

  5. Contribution of N-Nitrosamines and Their Precursors to Domestic Sewage by Greywaters and Blackwaters.

    Science.gov (United States)

    Zeng, Teng; Mitch, William A

    2015-11-17

    N-nitrosamines and their precursors are significant concerns for water utilities exploiting wastewater-impacted water supplies, particularly those practicing potable reuse of wastewater. Previous efforts to identify specific precursors in municipal wastewater accounting for N-nitrosamine formation have met with limited success. As an alternative, we quantified the relative importance of greywater (i.e., shower, kitchen sink, bathroom washbasin, and laundry) and blackwater (i.e., urine and feces) streams in terms of their loadings of ambient specific and total N-nitrosamines and chloramine-reactive and ozone-reactive N-nitrosamine precursors to domestic sewage. Accounting for the volume fractions of individual greywater and blackwater streams, laundry water represented the most significant source of N-nitrosamines and their precursors, followed by shower water and urine. Laundry water was particularly important for ozone-reactive N-nitrosamine precursors, accounting for ∼99% of N-nitrosodimethylamine (NDMA) precursors and ∼69% of precursors for other uncharacterized N-nitrosamines. For the other greywater streams, consumer products contributed additional N-nitrosamines and precursors, but the remarkable uniformity across different products suggested the importance of common macroconstituents. The consumption of a standard dose of the antacid ranitidine substantially increased NDMA and its chloramine-reactive precursors in urine. Nevertheless, nearly 40% of the American population would need to consume ranitidine daily to match the NDMA loadings from laundry water.

  6. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Science.gov (United States)

    Jolley, Katherine E

    2015-01-01

    Summary The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates. PMID:26734089

  7. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors.

    Science.gov (United States)

    Blacker, A John; Jolley, Katherine E

    2015-01-01

    The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72-100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates.

  8. [Chlorination byproducts formation potentials of typical nitrogenous organic compounds in water].

    Science.gov (United States)

    Xu, Qian; Xu, Bin; Qin, Cao; Xia, Sheng-Ji; Gao, Nai-Yun; Tian, Fu-Xiang; Li, Da-Peng

    2011-07-01

    Twelve typical nitrogenous organic compounds including herbicides, pesticides, amino acids, industrial products etc in polluted raw water were selected to investigate formation of typical carbonaceous and nitrogenous DBPs during chlorination and chloramination. To indentify the formation mechanism of carbonaceous and nitrogenous disinfection byproducts from nitrogenous chemicals, chlorination and chloroamination of urea herbicides, triazine herbicides, amino acid, and other compounds were investigated. As a result, the potential precursors for different DBPs were defined as well. It has been identified that widely used urea herbicides could produce as many as 9 specific DBPs. The chlorotoluron shows highest reactivity and yields chloroform (CF), monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), 1,1-dichloro-acetone (1,1-DCP), 1,1,1-trichloro-acetone (1,1,1-TCP), chloropicrin (NTCM), dichloro-acetonitrile (DCAN), dimethylnitrosamine (NDMA). The results indicated that aldicarb and dinoseb are important precursors of CF, DCAA, MCAA, NTCM as well. High concentrations of CF and DCAA were found during L-tryptophan chlorination. Furthermore, DBPs formation pathways and mechanisms were suggested during chlorination and chloramination of chlorotoluron, ametryn, dinoseb L-tryptophan.

  9. 基于大型工程实例评价两种常用的消毒方式%Evaluation of Two Disinfection Processes on the Basis of Large-scale Engineering Application

    Institute of Scientific and Technical Information of China (English)

    吴仲斯; 阳宇恒; 靳小虎; 周勤; 蔡展航

    2015-01-01

    In order to evaluate the effectiveness of two different types of disinfection processes, the production of disinfection byproducts and relevant capital costs for a water treatment plant, named A Water Treatment Plant, located in the south part of China, water quality analysis and determination of chlorine usage for the treated water by the two processes are conducted. It has been concluded that chloramine and chlorine are both effective. The concentration of chloroform and free chlorine in the water are rapidly increased after chlorine treatment. Additionally, the costs of chlorine are 70% of chloramine costs, which are relatively lower.%以某南方大都市A水厂为研究对象,通过对实际运行中消毒工艺变更前后的出厂水和管网水的水质和耗氯量进行分析,评价两种消毒工艺的消毒效果、副产物产生情况以及运营成本。结果表明:氯胺和液氯两种消毒剂均有良好的消毒效果;使用液氯后水中的三氯甲烷和游离氯的含量骤增;液氯消毒成本较低,约为氯胺消毒的70%。

  10. Disinfection byproduct formation from lignin precursors.

    Science.gov (United States)

    Hua, Guanghui; Kim, Junsung; Reckhow, David A

    2014-10-15

    Lignin is the most abundant aromatic plant component in terrestrial ecosystems. This study was conducted to determine the contribution of lignin residues in natural water to the formation of disinfection byproducts (DBPs) in drinking water. We investigated the formation of different classes of DBPs from lignin model compounds, lignin polymers, and humic substances using two common disinfection techniques, chlorination and chloramination. The contributions of lignin to the overall formation of DBPs from these organic products were determined based on the observed abundances of individual lignin phenols and their DBP yields. Model lignin phenols generally produced higher trichloroacetic acid (TCAA) yields than chloroform and dichloroacetic acid (DCAA) during chlorination. Lignin phenols generally produced higher DBP yields but lower percentages of unknown total organic halogen compared to bulk humic substances and lignin polymers. The relative significance of lignin phenols as chlorination DBP precursors generally follows the order of TCAA > DCAA&chloroform. The relative significance of lignin phenols to DBP formation by chloramination follows the order: TCAA > DCAA&DCAN > chloroform. Overall, lignin phenols are more important as TCAA precursors than as chloroform and DCAA precursors.

  11. Effect of Taurine on Acinar Cell Apoptosis and Pancreatic Fibrosis in Dibutyltin Dichloride-induced Chronic Pancreatitis

    Directory of Open Access Journals (Sweden)

    Sawa,Kiminari

    2012-08-01

    Full Text Available The relationship between pancreatic fibrosis and apoptosis of pancreatic acinar cells has not been fully elucidated. We reported that taurine had an anti-fibrotic effect in a dibutyltin dichloride (DBTC-chronic pancreatitis model. However, the effect of taurine on apoptosis of pancreatic acinar cells is still unclear. Therefore, we examined apoptosis in DBTC-chronic pancreatitis and in the AR42J pancreatic acinar cell line with/without taurine. Pancreatic fibrosis was induced by a single administration of DBTC. Rats were fed a taurine-containing diet or a normal diet and were sacrificed at day 5. The AR42J pancreatic acinar cell line was incubated with/without DBTC with taurine chloramines. Apoptosis was determined by using terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL assay. The expression of Bad and Bcl-2 proteins in the AR42J cells lysates was detected by Western blot analysis. The apoptotic index of pancreatic acinar cells in DBTC-administered rats was significantly increased. Taurine treatment inhibited pancreatic fibrosis and apoptosis of acinar cells induced by DBTC. The number of TUNEL-positive cells in the AR42J pancreatic acinar cell lines was significantly increased by the addition of DBTC. Incubation with taurine chloramines ameliorated these changes. In conclusion, taurine inhibits apoptosis of pancreatic acinar cells and pancreatitis in experimental chronic pancreatitis.

  12. The drinking water treatment process as a potential source of affecting the bacterial antibiotic resistance.

    Science.gov (United States)

    Bai, Xiaohui; Ma, Xiaolin; Xu, Fengming; Li, Jing; Zhang, Hang; Xiao, Xiang

    2015-11-15

    Two waterworks, with source water derived from the Huangpu or Yangtze River in Shanghai, were investigated, and the effluents were plate-screened for antibiotic-resistant bacteria (ARB) using five antibiotics: ampicillin (AMP), kanamycin (KAN), rifampicin (RFP), chloramphenicol (CM) and streptomycin (STR). The influence of water treatment procedures on the bacterial antibiotic resistance rate and the changes that bacteria underwent when exposed to the five antibiotics at concentration levels ranging from 1 to 100 μg/mL were studied. Multi-drug resistance was also analyzed using drug sensitivity tests. The results indicated that bacteria derived from water treatment plant effluent that used the Huangpu River rather than the Yangtze River as source water exhibited higher antibiotic resistance rates against AMP, STR, RFP and CM but lower antibiotic resistance rates against KAN. When the antibiotic concentration levels ranged from 1 to 10 μg/mL, the antibiotic resistance rates of the bacteria in the water increased as water treatment progressed. Biological activated carbon (BAC) filtration played a key role in increasing the antibiotic resistance rate of bacteria. Chloramine disinfection can enhance antibiotic resistance. Among the isolated ARB, 75% were resistant to multiple antibiotics. Ozone oxidation, BAC filtration and chloramine disinfection can greatly affect the relative abundance of bacteria in the community.

  13. Nitrogenous disinfection byproducts in English drinking water supply systems: Occurrence, bromine substitution and correlation analysis.

    Science.gov (United States)

    Bond, Tom; Templeton, Michael R; Mokhtar Kamal, Nurul Hana; Graham, Nigel; Kanda, Rakesh

    2015-11-15

    Despite the recent focus on nitrogenous disinfection byproducts in drinking water, there is limited occurrence data available for many species. This paper analyses the occurrence of seven haloacetonitriles, three haloacetamides, eight halonitromethanes and cyanogen chloride in 20 English drinking water supply systems. It is the first survey of its type to compare bromine substitution factors (BSFs) between the haloacetamides and haloacetonitriles. Concentrations of the dihalogenated haloacetonitriles and haloacetamides were well correlated. Although median concentrations of these two groups were lower in chloraminated than chlorinated surface waters, median BSFs for both in chloraminated samples were approximately double those in chlorinated samples, which is significant because of the higher reported toxicity of the brominated species. Furthermore, median BSFs were moderately higher for the dihalogenated haloacetamides than for the haloacetonitriles. This indicates that, while the dihalogenated haloacetamides were primarily generated from hydrolysis of the corresponding haloacetonitriles, secondary formation pathways also contributed. Median halonitromethane concentrations were remarkably unchanging for the different types of disinfectants and source waters: 0.1 μg · mgTOC(-1) in all cases. Cyanogen chloride only occurred in a limited number of samples, yet when present its concentrations were higher than the other N-DBPs. Concentrations of cyanogen chloride and the sum of the halonitromethanes were not correlated with any other DBPs.

  14. Enhanced formation of disinfection byproducts in shale gas wastewater-impacted drinking water supplies.

    Science.gov (United States)

    Parker, Kimberly M; Zeng, Teng; Harkness, Jennifer; Vengosh, Avner; Mitch, William A

    2014-10-01

    The disposal and leaks of hydraulic fracturing wastewater (HFW) to the environment pose human health risks. Since HFW is typically characterized by elevated salinity, concerns have been raised whether the high bromide and iodide in HFW may promote the formation of disinfection byproducts (DBPs) and alter their speciation to more toxic brominated and iodinated analogues. This study evaluated the minimum volume percentage of two Marcellus Shale and one Fayetteville Shale HFWs diluted by fresh water collected from the Ohio and Allegheny Rivers that would generate and/or alter the formation and speciation of DBPs following chlorination, chloramination, and ozonation treatments of the blended solutions. During chlorination, dilutions as low as 0.01% HFW altered the speciation toward formation of brominated and iodinated trihalomethanes (THMs) and brominated haloacetonitriles (HANs), and dilutions as low as 0.03% increased the overall formation of both compound classes. The increase in bromide concentration associated with 0.01-0.03% contribution of Marcellus HFW (a range of 70-200 μg/L for HFW with bromide = 600 mg/L) mimics the increased bromide levels observed in western Pennsylvanian surface waters following the Marcellus Shale gas production boom. Chloramination reduced HAN and regulated THM formation; however, iodinated trihalomethane formation was observed at lower pH. For municipal wastewater-impacted river water, the presence of 0.1% HFW increased the formation of N-nitrosodimethylamine (NDMA) during chloramination, particularly for the high iodide (54 ppm) Fayetteville Shale HFW. Finally, ozonation of 0.01-0.03% HFW-impacted river water resulted in significant increases in bromate formation. The results suggest that total elimination of HFW discharge and/or installation of halide-specific removal techniques in centralized brine treatment facilities may be a better strategy to mitigate impacts on downstream drinking water treatment plants than altering

  15. Study and development of a radioimmunoassay of antidiuretic hormone sensitive at 10/sup -12/M

    Energy Technology Data Exchange (ETDEWEB)

    Caillens, H.; Rousselet, F. (Faculte des Sciences Pharmaceutiques, (France)); Paillard, F. (Hopital Tenon, Paris (France))

    1982-07-01

    A radioimmunoassay of antidiuretic hormone is described. The antiserum was obtained by immunization of rabbits with lysine vasopressin conjugated to hemocyanine. The specificity of the antibody was selective and directed against the pentapeptide ring of the vasopressin molecule: oxytocin showed no cross-reactivity at 10/sup -9/M. The labelled hormone (/sup 125/I-AVP) prepared using the chloramine-T method had a high specific activity (1860 Ci/mmol). Incubation was performed in an equilibrium system. Comparative studies of different separation methods of bounds and free /sup 125/I-AVP showed that the sensitivity and the precision of the standard curve were better using charcoal dextran. The limit of detection of the assay was 1,6 pg per ml.

  16. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment.

    Science.gov (United States)

    Postigo, Cristina; Richardson, Susan D

    2014-08-30

    Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment.

  17. Radioimmunoassay of secretin in human serum

    Energy Technology Data Exchange (ETDEWEB)

    Bonora, G.; Vezzadini, P.; Toni, R.; Labo, G. (Bologna Univ. (Italy))

    1984-06-27

    A sensitive radioimmunoassay for secretin has been developed. Antisera were raised against synthetic porcine secretin coupled to bovine serum albumin. N-..cap alpha..-desaminotyrosyl-..beta..-alanyl secretin was radioiodinated by a slight modification of the chloramine-T method. Pure synthetic porcine secretin was used as a standard. Free and bound hormone were separated by dextran-coated charcoal. No cross-reactivity was found with structurally and physiologically related peptides. The sensitivity of the assay was high enough to measure fasting secretin levels in human serum. Patients with acute or chronic pancreatitis had mean serum secretin concentration not significantly different from healthy subjects. In patients with pancreatic carcinoma the mean serum secretin concentration was significantly lower than in healthy subjects, although a wide overlap of the two groups was evident.

  18. Physico-chemical technologies for nitrogen removal from wastewaters: a review

    Directory of Open Access Journals (Sweden)

    Andrea G. Capodaglio

    2015-07-01

    Full Text Available The paper examines the main physico-chemical processes for nitrogen removal from wastewaters, considering both those that have been long known and still widely applied at the industrial scale, and those that are still at the research level. Special attention is paid to the latest technological developments, as well as to operational problems and fields of application. The processes considered are briefly summarized as follows: ammonia air and steam stripping; ammonia vacuum distillation; ammonia precipitation as struvite; ammonia and nitrate removal by selected ion exchange; breakpoint chlorination; chloramine removal by selected activated carbon; ammonia adsorption on charcoal; chemical reduction of nitrate; advanced oxidation processes to convert ammonia and organic-N into nitrogen gas or nitrate. Special attention is given to advanced oxidation processes, as great research efforts are currently addressed to their implementation. These specifically include ozonation, peroxon oxidation, catalytic wet air oxidation, photo-catalytic oxidation and electrochemical oxidation.

  19. Determination of the odor threshold concentrations of chlorobrominated anisoles in water.

    Science.gov (United States)

    Diaz, Alfredo; Fabrellas, Cristina; Ventura, Francesc; Galceran, M Teresa

    2005-01-26

    Trihalophenols, which are drinking water disinfection byproducts (DBPs) formed by chlorination or chloramination practices, can be biomethylated into trihalogenated anisoles. These latter compounds have traditionally been suspected of causing odor episodes in drinking water around the world. The odor threshold concentration (OTC) of mixed chlorobrominated anisoles, which were previously synthesized, was determined by flavor profile analysis (FPA) performed by an experienced panel trained to identify odors and tastes in water. The odor threshold amount (OTA) was evaluated by using a gas chromatograph equipped with olfactometry (GC-O) and electron capture detectors (ECD). FPA results for mixed chlorobromoanisoles gave a theoretical OTCs range from 2 to 30 ng/L, the 2,6-diBr-3Cl-anisole being the most odorous compound. Rubber is the general descriptor described by panelists for these compounds, although earthy and musty are the following most cited descriptors.

  20. Linking water treatment practices and fish welfare

    DEFF Research Database (Denmark)

    Zubiaurre, Claire; Pedersen, Lars-Flemming

    2016-01-01

    Peracetic acids can be used as sanitizers to control water quality in aquaculture systems. As an alternative to formalin, chloramine-T or copper sulphate, PAA has strong anti-microbial effects, degrades quickly and is relatively safe to use. Its mode of action and associated rapid decay can make...... optimizing treatment protocols a challenge. Continuous low-dose applications seem to be a promising solution. In this preliminary study behavioral response was used to assess potential correlations with PAA dosage. A behavioral change or response is not necessarily an indication of compromised welfare....... Supportive enzymatic, biochemical and physiological biomarkers can be used along with gill and epidermal histological measures to evaluate the effects on water treatment regimens. The ultimate goal is to define the therapeutic window where fish welfare is not compromised.PAA is among the few disinfectants...

  1. UP-REGULATION OF HEPATIC RECEPTOR FOR GROWTH HORMONE IN THE FLOUNDER (PARALICHTHYS OLIVACEUS) AFTER ORAL ADMINISTRATION WITH EXOGENOUS GH

    Institute of Scientific and Technical Information of China (English)

    刘宗柱; 王金宝; 徐永立; 王勇; 张培军

    2001-01-01

    The iodination efficiency of salmon GH (sGH) was 38.82%,using a modification of the chloramine-T method. The specific activity of the 125I-sGH was about 40 μCi/μg protein. The results of binding assay showed a single class of high affinity and low-capacity binding site in flounder liver. Long-term administration with exogenous GH can induce the up-regulation of hepatic GH receptor in total binding capacity though there was no significant difference of association constant among any groups. Con-sidering that there was no significant difference in capacity of free binding sites of livers from control and experimental fish, this result also indicated that the liver from experimental fish, compared to that from control fish, had more occupied binding sites.

  2. UP-REGULATION OF HEPATIC RECEPTOR FOR GROWTH HORMONE IN THE FLOUNDER (PARALICHTHYS OLIVACEUS) AFTER ORAL ADMINISTRATION WITH EXOGENOUS GH

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The iodination efficiency of salmon GH(Sgh) was 38.82%,using a modification of the chloramine-T method. The specific activity of the 125I-Sgh was about 40 μCi/μg protein. The results of binding assay showed a single class of high affinity and low-capacity binding site in flounder liver. Long-term administration with exogenous GH can induce the up-regulation of hepatic GH receptor in total binding capacity though there was no significant difference of association constant among any groups. Considering that there was no significant difference in capacity of free binding sites of livers from control and experimental fish, this result also indicated that the liver from experimental fish, compared to that from control fish, had more occupied binding sites.

  3. Synthesis and preliminary biological evaluation of [{sup 123}I]Me{sub 2}Pyr, a new potential ligand for imaging of central cannabinoid CB{sub 1} receptors

    Energy Technology Data Exchange (ETDEWEB)

    Gielow, P. [Department of Nuclear Medicine, University School of Medicine, Carl-Neuberg-Str. 1, D-30625 Hannover (Germany)]. E-mail: gielow.peter@mh-hannover.de; Klinge, P. [International Neuroscience Institute, Alexis Carrel Str. 4, D-30625 Hannover (Germany); Knapp, W.H. [Department of Nuclear Medicine, University School of Medicine, Carl-Neuberg-Str. 1, D-30625 Hannover (Germany); Berding, G. [Department of Nuclear Medicine, University School of Medicine, Carl-Neuberg-Str. 1, D-30625 Hannover (Germany)

    2006-07-15

    A synthesis of 1-(2,4-dichlorophenyl)-5-(4-[{sup 123}I]iodophenyl)-4-methyl-1H-pyrazole -3-carboxylic acid N',N'-dimethyl-hydrazide ([{sup 123}I]Me{sub 2}Pyr), a new radioiodinated analogue of the high-affinity cannabinoid CB{sub 1} receptor antagonist SR141716A, is described. Labelling was achieved by radioiododestannylation of the tributylstannyl precursor with [{sup 123}I]iodide in the presence of chloramine T. HPLC purification afforded the labelled product in 48% radiochemical yield. Preliminary rat brain biodistribution studies with the {sup 125}I labelled compound revealed high uptake in the substantia nigra, the globus pallidus externus and the cerebellum, which is consistent with the known distribution of CB{sub 1} receptors.

  4. Microwave-Assisted Solution Phase Synthesis of Novel 2-{4-[2-(N-Methyl-2-pyridylaminoethoxy]phenyl}-5-Substituted 1,3,4-Oxadiazole  Library

    Directory of Open Access Journals (Sweden)

    Santosh L. Gaonkar

    2011-01-01

    Full Text Available A new series of 2-{4-[2-(N-methyl-2-pyridylaminoethoxy]phenyl}-5-substituted 1,3,4-oxadiazoles were synthesized by the oxidative cyclization of hydrazones derived from 4-[2-(methylpyridin-2-ylaminoethoxy]benzaldehyde and aryl hydrazines using chloramine-T as an efficient catalyst. All steps were assisted by microwave irradiation. Microwave enables all these reactions to be simple, rapid, high yielding, and avoid chromatograph purification and led environmentally benign total synthesis of focused oxadiazole library. All the synthesized compounds were isolated in good yield and characterized by 1H NMR, 13C NMR, and elemental analyses. The title compounds represent a novel class of biologically active heterocycles.

  5. Synthesis and antimicrobial studies of a new series of 2-[4-[2-(5-ethylpyridin-2-yl)ethoxy]phenyl]-5-substituted-1,3,4-oxadiazoles.

    Science.gov (United States)

    Gaonkar, S L; Rai, K M L; Prabhuswamy, B

    2006-07-01

    A series of novel 2-[4-[2-(5-ethylpyridin-2-yl)ethoxy]phenyl]-5-substituted-1,3,4-oxadiazoles were synthesized by the oxidative cyclisation of hydrazones derived from 4-[2-(5-ethylpyridin-2-yl)ethoxy]benzaldehyde and aroylhydrazines using chloramine-T as oxidant. IR, NMR and elemental analysis characterized the newly synthesized compounds. The synthesized compounds were evaluated for their antimicrobial activity and were compared with standard drugs. The compounds demonstrated potent to weak antimicrobial activity. Out of the compounds studied, compounds 8c and 8d showed significant inhibition. Compounds 8b, 8f, 8k and 8e showed moderate activity. The minimum inhibitory concentration of the compounds was in the range of 8-26 microg ml(-1) against bacteria and 8-24 microg ml(-1) against fungi. The title compounds represent a novel class of potent antimicrobial agents.

  6. Mild radioiodination of insulin with dichloramine-T

    Energy Technology Data Exchange (ETDEWEB)

    Jyotsna, T.; Pillai, M.R.A.; Gupte, J.H.; Mani, R.S.

    1986-01-01

    Iodination of insulin using N-dichloro-p-toluene sulphonamide(dichloramine-T) has been standardised. Dichloramine-T, a water insoluble derivative of chloramine-T showed excellent properties as an iodination reagent, for the preparation of radiolabeled insulin for use in radioimmunoassay. Iodination using dichloramine-T could be done at as low as 0.5-2 ..mu..g of the reagent, and at this concentration the molar ratio worked out to 1:3 to 1:12 (protein: dichloramine-T). Iodination yields of greater than 90% were obtained at pH 5-7. Evaluation of the iodinated tracer for suitability in radioimmunoassay was carried out by estimating radiochemical purity, immunological purity, non specific binding and stability on storage.

  7. Protein aggregation and degradation during iodine labeling and its consequences for protein adsorption to biomaterials

    DEFF Research Database (Denmark)

    Holmberg, Maria; Jensen, Karin Bagger Stibius; Ndoni, Sokol;

    2007-01-01

    were analyzed through chromatography and spectroscopy techniques. Results show that the iodine labeling method using chloramine-T (CAT) as an oxidizing agent can cause both enhanced aggregation and fragmentation of proteins. Albumin shows an enhanced tendency to aggregate after iodine labeling using......Protein adsorption on modified and unmodified polymer surfaces investigated through radiolabeling experiments showed a tendency for higher than expected albumin and immunoglobulin G (IgG) adsorption. Possible enhanced protein aggregation and degradation caused by the iodine labeling method used...... of protein adsorption should be used with caution and preferably should be validated by a label-free methodology for each combination of radio-label and protein. The results obtained in this study can be used to optimize investigation of protein adsorption on surfaces of materials for biomedical devices. (c...

  8. Sensitivity of juvenile striped bass to chemicals used in aquaculture

    Energy Technology Data Exchange (ETDEWEB)

    Bills, T.D.; Marking, L.L.; Howe, G.E.

    1993-01-01

    Efforts to restore anadromous striped bass (Morone saxatilis) populations by the U.S. Fish and Wildlife Service and other agencies over the past 20 years have concentrated on hatchery culture to supplement dwindling natural reproduction. Adult fish captured for artificial spawning are stressed by handling and crowding in rearing ponds and are often exposed to therapeutants, anesthetics, disinfectants, and herbicides used in fish culture. The authors determined the toxicity of 17 fishery chemicals (chloramine-T, erythromycin, formalin, Hyamine 3500, Roccal, malachite green, sulfamerazine, benzocaine, etomidate, Finquel (MS-222), metomidate, quinaldine sulfate, chlorine, potassium permanganate, Aquazine, copper sulfate, and Rodeo) to striped bass fry (average weight = 1 g) in reconstituted water (total hardness 40 mg/L) at 12 degrees C. The 96-h LC50's (concentration calculated to produce 50% mortality in a population) ranged from 0.129 mg/L for malachite green to 340 mg/L for erythromycin.

  9. Chemical modification of amino acid residues in glycerinated Vorticella stalk and Ca(2+)-induced contractility.

    Science.gov (United States)

    Kono, R; Ochiai, T; Asai, H

    1997-01-01

    The glycerinated stalk of the peritrich ciliate Vorticella, was treated with various reagents to chemically modify the amino acid residues. The influences of these modifcations on spasmoneme contractility were investigated. First, it was confirmed that the spasmoneme contraction is not inhibited by alteration of SH groups. It was also demonstrated that chemical modification of methionine and tryptophan residues abolishes spasmoneme contractility. The reagents used for chemical modification were N-bromosuccinimide (NBS), chloramine T, and 2-hydroxy-5-nitrobenzyl bromide (HNBB), which abolished spasmoneme contractility at concentrations of 40-50 microM, 200-300 microM, and 4 mM, respectively. These results suggest that, along with Ca2+ binding proteins, there are other as yet to be identified proteins involved in contractility.

  10. Hypochlorite-induced damage to proteins

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    1998-01-01

    Stimulated monocytes and neutrophils generate hypochlorite (HOCl) via the release of the enzyme myeloperoxidase and hydrogen peroxide. HOCl damages proteins by reaction with amino acid side-chains or backbone cleavage. Little information is available about the mechanisms and intermediates involved...... in these reactions. EPR spin trapping has been employed to identify radicals on proteins, peptides and amino acids after treatment with HOCl. Reaction with HOCl gives both high- and low-molecular-mass nitrogen-centred, protein-derived radicals; the yield of the latter increases with both higher HOCl:protein ratios...... and enzymic digestion. These radicals, which arise from lysine side-chain amino groups, react with ascorbate, glutathione and Trolox. Reaction of HOCl-treated proteins with excess methionine eliminates radical formation, which is consistent with lysine-derived chloramines (via homolysis of N-Cl bonds) being...

  11. Radioimmunoassay determination of decreased amounts of. cap alpha. -L-fucosidase protein in fucosidosis

    Energy Technology Data Exchange (ETDEWEB)

    Andrews-Smith, G.L.; Alhadeff, J.A. (California Univ., San Diego, La Jolla (USA). Dept. of Neurosciences)

    1982-03-15

    Purified human liver ..cap alpha..-L-fucosidase (EC 3.2.1.51) has been radioiodinated by a chloramine-T procedure to a specific activity of 3.7 x 10/sup 6/ dpm/..mu..g protein without altering its apparent Michaelis constant for the 4-methylumbelliferyl substrate. This /sup 125/I-labeled ..cap alpha..-L-fucosidase has been used in development of a competitive binding radioimmunoassay for ..cap alpha..-L-fucosidase which can detect 1-2 ng of enzyme protein and has been employed to quantify the amount of ..cap alpha..-L-fucosidase protein in the liver and spleen from a patient with fucosidosis. Less than 1% of the normal amount of ..cap alpha..-L-fucosidase protein is present suggesting that normal amounts of catalytically inactive ..cap alpha..-L-fucosidase are not found in this disease.

  12. Recent advances in drinking water disinfection: successes and challenges.

    Science.gov (United States)

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    , it is recommended that water disinfection should never be compromised by attempting to control DBPs. The reason for this is that the risks of human illness and death from pathogens in drinking water are much greater than the risks from exposure to disinfectants and disinfection by-products. Nevertheless, if DBP levels exceed regulatory limits, strategies should focus on eliminating organic impurities that foster their formation, without compromising disinfection. As alternatives to chlorine, disinfectants such as chloramines, ozone, chlorine dioxide, and UV disinfection are gaining popularity. Chlorine and each of these disinfectants have individual advantage and disadvantage in terms of cost, efficacy-stability, ease of application, and nature of disinfectant by-products (DBPs). Based on efficiency, ozone is the most efficient disinfectant for inactivating bacteria, viruses, and protozoa. In contrast, chloramines are the least efficient and are not recommended for use as primary disinfectants. Chloramines are favored for secondary water disinfection, because they react more slowly than chlorine and are more persistent in distribution systems. In addition, chloramines produce lower DBP levels than does chlorine, although microbial activity in the distribution system may produce nitrate from monochloramine, when it is used as a residual disinfectant, Achieving the required levels of water quality, particularly microbial inactivation levels, while minimizing DBP formation requires the application of proper risk and disinfection management protocols. In addition, the failure of conventional treatment processes to eliminate critical waterborne pathogens in drinking water demand that improved and/or new disinfection technologies be developed. Recent research has disclosed that nanotechnology may offer solutions in this area, through the use of nanosorbents, nanocatalysts, bioactive nanoparticles, nanostructured catalytic membranes, and nanoparticle-enhanced filtration.

  13. Inhibition of myeloperoxidase: evaluation of 2H-indazoles and 1H-indazolones.

    Science.gov (United States)

    Roth, Aaron; Ott, Sean; Farber, Kelli M; Palazzo, Teresa A; Conrad, Wayne E; Haddadin, Makhluf J; Tantillo, Dean J; Cross, Carroll E; Eiserich, Jason P; Kurth, Mark J

    2014-11-15

    Myeloperoxidase (MPO) produces hypohalous acids as a key component of the innate immune response; however, release of these acids extracellularly results in inflammatory cell and tissue damage. The two-step, one-pot Davis-Beirut reaction was used to synthesize a library of 2H-indazoles and 1H-indazolones as putative inhibitors of MPO. A structure-activity relationship study was undertaken wherein compounds were evaluated utilizing taurine-chloramine and MPO-mediated H2O2 consumption assays. Docking studies as well as toxicophore and Lipinski analyses were performed. Fourteen compounds were found to be potent inhibitors with IC50 values <1μM, suggesting these compounds could be considered as potential modulators of pro-oxidative tissue injury pertubated by the inflammatory MPO/H2O2/HOCl/HOBr system.

  14. Preparation of 125I-protein A usable for up to 10 months in immunoassays

    DEFF Research Database (Denmark)

    Dyrberg, T; Billestrup, Nils

    1984-01-01

    Chloramine-T iodination of protein A from Staphylococcus aureus and gel electrophoretic purification of the iodination mixture results in a stable tracer of high specific and functional activity. Following repeated gel electrophoresis of the tracer only a single component was observed. The specific...... activity of the 125I-protein A was between 30 and 55 muCi/micrograms. The binding of 125I-protein A to rabbit immunoglobulin exceeded 90% and the tracer competed effectively with unlabelled protein A in binding to cells incubated with sera containing surface antibodies. Storage of the tracer for up to 46...... weeks resulted in a moderate decrease in maximal binding to immunoglobulin (from 91% to 64%), in TCA precipitable radioactivity (from 97% to 80%) and an approx. 30% decrease in the ability to detect cell bound immunoglobulin. It is concluded that gel electrophoretic purification of 125I-protein...

  15. Drinking Water Disinfection by In-line Electrolysis: Product and Inorganic By-Product Formation

    Science.gov (United States)

    Bergmann, M. E. Henry

    This section covers peculiarities of so-called in-line electrolysis when drinking water is electrolysed to produce disinfection species killing microorganisms. Mainly mixed oxide electrodes (MIO) based on IrO2 and/or RuO2 coatings and boron-doped diamond electrodes were used in the studies. Artificial and real drinking water systems were electrolysed in continuous and discontinuous operating mode, varying water composition, current density and electrode materials. Results show, besides the ability of producing active chlorine, risks of inorganic disinfection by-products (DBPs) such as chlorate, perchlorate, nitrite, ammonium, chloramines, hydrogen peroxide and others. DBPs are responsible for analysis errors using DPD method for active chlorine measurements. Geometry may influence by-product yield. As a conclusion, the necessity of developing test routines for practical cell applications must be underlined.

  16. 水处理组合消毒方式分析%Analysis of Combined Disinfectants in Water Treatment

    Institute of Scientific and Technical Information of China (English)

    黄旦光

    2012-01-01

    消毒的主要目的是为了灭活水中的致病微生物。水厂中主要被使用的消毒剂有氯、氯胺、臭氧、二氧化氯和紫外线。综合分析其消毒效巢和优缺点。重点介绍了多种组合消毒方式,以及分析其在水厂消毒中改善消毒效果和控制消毒副产物方面的应用。%The main objective of disinfecting is inactivating microorganism in water. The commonly used disinfectants in water treatment are chlorine, chloramines, chlorine dioxide, ozone, and UV. It is discussed about their advantages and disadvantages. It introduces some combined disinfectants and their special function on disinfecting improving and disinfection byproduct controlling.

  17. Kinetic Model for the Radical Degradation of Tri-Halonitromethane Disinfection Byproducts in Water

    Energy Technology Data Exchange (ETDEWEB)

    Stephen P. Mezyk; Bruce J. Mincher; William J. Cooper; S. Kirkham Cole; Robert V. Fox; Pieror R. Gardinali

    2012-10-01

    The halonitromethanes (HNMs) are byproducts of the ozonation and chlorine/chloramine treatment of drinking waters. Although typically occurring at low concentrations HNMs have high cytotoxicity and mutagenicity, and may therefore represent a significant human health hazard. In this study, we have investigated the radical based mineralization of fully-halogenated HNMs in water using the congeners bromodichloronitromethane and chlorodibromonitromethane. We have combined absolute reaction rate constants for their reactions with the hydroxyl radical and the hydrated electron as measured by electron pulse radiolysis and analytical measurements of stable product concentrations obtained by 60Co steady-state radiolysis with a kinetic computer model that includes water radiolysis reactions and halide/nitrogen oxide radical chemistry to fully elucidate the reaction pathways of these HNMs. These results are compared to our previous similar study of the fully chlorinated HNM chloropicrin. The full optimized computer model, suitable for predicting the behavior of this class of compounds in irradiated drinking water is provided.

  18. Kinetic model for the radical degradation of tri-halonitromethane disinfection byproducts in water

    Science.gov (United States)

    Mezyk, Stephen P.; Mincher, Bruce J.; Cooper, William J.; Kirkham Cole, S.; Fox, Robert V.; Gardinali, Piero R.

    2012-10-01

    The halonitromethanes (HNMs) are byproducts of the ozonation and chlorine/chloramine treatment of drinking waters. Although typically occurring at low concentrations HNMs have high cytotoxicity and mutagenicity, and may therefore represent a significant human health hazard. In this study, we have investigated the radical based mineralization of fully-halogenated HNMs in water using the congeners bromodichloronitromethane and chlorodibromonitromethane. We have combined absolute reaction rate constants for their reactions with the hydroxyl radical and the hydrated electron as measured by electron pulse radiolysis and analytical measurements of stable product concentrations obtained by 60Co steady-state radiolysis with a kinetic computer model that includes water radiolysis reactions and halide/nitrogen oxide radical chemistry to fully elucidate the reaction pathways of these HNMs. These results are compared to our previous similar study of the fully chlorinated HNM chloropicrin. The full optimized computer model, suitable for predicting the behavior of this class of compounds in irradiated drinking water, is provided.

  19. The high reactivity of peroxiredoxin 2 with H(2)O(2) is not reflected in its reaction with other oxidants and thiol reagents.

    Science.gov (United States)

    Peskin, Alexander V; Low, Felicia M; Paton, Louise N; Maghzal, Ghassan J; Hampton, Mark B; Winterbourn, Christine C

    2007-04-20

    Peroxiredoxin 2 is a member of the mammalian peroxiredoxin family of thiol proteins that is important in antioxidant defense and redox signaling. We have examined its reactivity with various biological oxidants, in order to assess its ability to act as a direct physiological target for these species. Human erythrocyte peroxiredoxin 2 was oxidized stoichiometrically to its disulfide-bonded homodimer by hydrogen peroxide, as monitored electrophoretically under nonreducing conditions. The protein was highly susceptible to oxidation by adventitious peroxide, which could be prevented by treating buffers with low concentrations of catalase. However, this did not protect peroxiredoxin 2 against oxidation by added H(2)O(2). Experiments measuring inhibition of dimerization indicated that at pH 7.4 catalase and peroxiredoxin 2 react with hydrogen peroxide at comparable rates. A rate constant of 1.3 x 10(7) M(-1) s(-1) for the peroxiredoxin reaction was obtained from competition kinetic studies with horseradish peroxidase. This is 100-fold faster than is generally assumed. It is sufficiently high for peroxiredoxin to be a favored cellular target for hydrogen peroxide, even in competition with catalase or glutathione peroxidase. Reactions of t-butyl and cumene hydroperoxides with peroxiredoxin were also fast, but amino acid chloramines reacted much more slowly. This contrasts with other thiol compounds that react many times faster with chloramines than with hydrogen peroxide. The alkylating agent iodoacetamide also reacted extremely slowly with peroxiredoxin 2. These results demonstrate that peroxiredoxin 2 has a tertiary structure that facilitates reaction of the active site thiol with hydrogen peroxide while restricting its reactivity with other thiol reagents.

  20. Removal of cyclops in pre-oxidizing cooperation water treatment process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Zooplankton cyclops propagates profusely in waterbody, cannot be effectively inactivated by conventional disinfection process, and becomes a troublesome drinking water treatment problem. In this work, the qualitative and quantitative experimental studies were carried out on inactivation of zooplankton cyclops using oxidants, such as chlorine (Cl2), chlorine dioxide (ClO2), ozone (O3), hydrogen peroxide (H2O2), ozone/hydrogen peroxide (O3/H2O2), chloramines (Cl2-NH3) and potassium permanganate (KMnO4). The influences of various factors include different oxidant dosages, organic substance contents and pH values. The results showed that currently available oxidants used all might inactivate cyclops in some extent. According to the experimental results, chlorine dioxide, ozone, ozone/hydrogen peroxide and chloramines can be selected as effective oxidants for inactivating cyclops because of their strong inactivation abilities. Then the synergic removal effects on cyclops with ozone,ozone/hydrogen peroxide pre-oxidation followed by conventional water treatment processes were investigated. The results showed that ozone and ozone/hydrogen peroxide pre-oxidation can inactivate cyclops effectively, which then can be removed thoroughly by conventional water treatment processes. Cyclops cannot appear in water after filtration with 1.65 mg/L of ozone and 6 mg/L of hydrogen peroxide, with the inactivation rate being 62% before conventional water treatment processes. Cyclops cannot appear in water after filtration with 1.8 mg/L of ozone, with the inactivation rate being 50% before conventional water treatment processes. For different oxidants, when removal rate was the best, the inactivation rate was not the same. These results may provide reference and model for actual waterworks.

  1. L-Tyrosine-loaded nanoparticles increase the antitumoral activity of direct electric current in a metastatic melanoma cell model

    Directory of Open Access Journals (Sweden)

    Vânia Emerich Bucco de Campos

    2010-11-01

    Full Text Available Vânia Emerich Bucco de Campos1, Cesar Augusto Antunes Teixeira1, Venicio Feo da Veiga2, Eduardo Ricci Júnior1, Carla Holandino11Departamento de Medicamentos, Faculdade de Farmácia, 2Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, BrazilAbstract: Inhibition of tumor growth induced by treatment with direct electric current (DC has been reported in several models. One of the mechanisms responsible for the antitumoral activity of DC is the generation of oxidative species, known as chloramines. With the aim of increasing chloramine production in the electrolytic medium and optimizing the antitumoral effects of DC, poly(e-caprolactone (PCL nanoparticles (NPs loaded with the amino acid tyrosine were obtained. The physical–chemical characterization showed that the NPs presented size in nanometric range and monomodal distribution. A slightly negative electrokinetic potential was also found in both blank NPs and L-tyrosine-loaded PCL NPs. The yield of the loading process was approximately 50%. Within 3 h of dissolution assay, a burst release of about 80% L-tyrosine was obtained. The in vitro cytotoxicity of DC was significantly increased when associated with L-tyrosine-loaded NPs, using a murine multidrug-resistant melanoma cell line model. This study showed that the use of the combination of nanotechnology and DC has a promising antineoplastic potential and opens a new perspective in cancer therapy.Keywords: direct electric current, nanotechnology, cancer therapy, L-tyrosine, B16F10 cells

  2. Bioanalytical assessment of the formation of disinfection byproducts in a drinking water treatment plant.

    Science.gov (United States)

    Neale, Peta A; Antony, Alice; Bartkow, Michael E; Farré, Maria José; Heitz, Anna; Kristiana, Ina; Tang, Janet Y M; Escher, Beate I

    2012-09-18

    Disinfection of drinking water is the most successful measure to reduce water-borne diseases and protect health. However, disinfection byproducts (DBPs) formed from the reaction of disinfectants such as chlorine and monochloramine with organic matter may cause bladder cancer and other adverse health effects. In this study the formation of DBPs through a full-scale water treatment plant serving a metropolitan area in Australia was assessed using in vitro bioanalytical tools, as well as through quantification of halogen-specific adsorbable organic halogens (AOXs), characterization of organic matter, and analytical quantification of selected regulated and emerging DBPs. The water treatment train consisted of coagulation, sand filtration, chlorination, addition of lime and fluoride, storage, and chloramination. Nonspecific toxicity peaked midway through the treatment train after the chlorination and storage steps. The dissolved organic matter concentration decreased after the coagulation step and then essentially remained constant during the treatment train. Concentrations of AOXs increased upon initial chlorination and continued to increase through the plant, probably due to increased chlorine contact time. Most of the quantified DBPs followed a trend similar to that of AOXs, with maximum concentrations observed in the final treated water after chloramination. The mostly chlorinated and brominated DBPs formed during treatment also caused reactive toxicity to increase after chlorination. Both genotoxicity with and without metabolic activation and the induction of the oxidative stress response pathway showed the same pattern as the nonspecific toxicity, with a maximum activity midway through the treatment train. Although measured effects cannot be directly translated to adverse health outcomes, this study demonstrates the applicability of bioanalytical tools to investigate DBP formation in a drinking water treatment plant, despite bioassays and sample preparation not

  3. Reactive species modify NaV1.8 channels and affect action potentials in murine dorsal root ganglion neurons.

    Science.gov (United States)

    Schink, Martin; Leipold, Enrico; Schirmeyer, Jana; Schönherr, Roland; Hoshi, Toshinori; Heinemann, Stefan H

    2016-01-01

    Dorsal root ganglion (DRG) neurons are important relay stations between the periphery and the central nervous system and are essential for somatosensory signaling. Reactive species are produced in a variety of physiological and pathophysiological conditions and are known to alter electric signaling. Here we studied the influence of reactive species on the electrical properties of DRG neurons from mice with the whole-cell patch-clamp method. Even mild stress induced by either low concentrations of chloramine-T (10 μM) or low-intensity blue light irradiation profoundly diminished action potential frequency but prolonged single action potentials in wild-type neurons. The impact on evoked action potentials was much smaller in neurons deficient of the tetrodotoxin (TTX)-resistant voltage-gated sodium channel NaV1.8 (NaV1.8(-/-)), the channel most important for the action potential upstroke in DRG neurons. Low concentrations of chloramine-T caused a significant reduction of NaV1.8 peak current and, at higher concentrations, progressively slowed down inactivation. Blue light had a smaller effect on amplitude but slowed down NaV1.8 channel inactivation. The observed effects were less apparent for TTX-sensitive NaV channels. NaV1.8 is an important reactive-species-sensitive component in the electrical signaling of DRG neurons, potentially giving rise to loss-of-function and gain-of-function phenomena depending on the type of reactive species and their effective concentration and time of exposure.

  4. Labeling of the Recombinant Streptokinase Using Iodine-131 as a New Thrombolytic Agent

    Directory of Open Access Journals (Sweden)

    I. Daruwati

    2012-12-01

    Full Text Available Stroke and acute myocardial infarction is a disease with the highest mortality in the world. WHO has estimated in 2008, 30% of deaths from heart disease and more than 80% of this cases have been occurred in developing countries. Streptokinase (SK as an effective thrombolytic agent has been used as a drug of choice for about forty years ago. SK is plasminogen (PG activator that converts plasminogen to active protease, called plasmin (PN which degrades fibrin to soluble products. Recombinant streptokinase (SKA from genetic engineering has been developed at School of Pharmacy ITB to reduce or eliminate immunogenicity of SK. However, scientific disclosures relating to dynamic and its kinetic studies in the body have still to be proven. One method that can explain this phenomenon is the pharmacological studies using radionuclide labeled compounds. Radioiodine labeled compound is used extensively and most suitable for biological studies. This paper describes the preparation of 131I-SKA and its characterization. The labeling conditions of SKA, such as chloramine-T as an oxidizing agent, amount of SKA, incubation time, and size of resin to purify the labeling yield have been observed. The result showed that the optimum condition of labeling (35.11% was obtained using 10 µg of chloramine-T and 60 seconds of incubation time. The highest radiochemical purity (97.46 ± 1.14% has also been obtained by passing through the resin chromatography column using 100 mg Dowex 1x8, size 50-100 mesh. The characterization of 131I-SKA with SDS PAGE method and autoradiography showed the similar performance with unlabeled-SKA

  5. Kinetics of the oxidation of cylindrospermopsin and anatoxin-a with chlorine, monochloramine and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Sordo, Ana; Metcalf, James S; Acero, Juan L

    2007-05-01

    Cyanobacteria produce toxins that may contaminate drinking water sources. Among others, the presence of the alkaloid toxins cylindrospermopsin (CYN) and anatoxin-a (ANTX) constitutes a considerable threat to human health due to the acute and chronic toxicity of these compounds. In the present study, not previously reported second-order rate constants for the reactions of CYN and ANTX with chlorine and monochloramine and of CYN with potassium permanganate were determined and the influence of pH and temperature was established for the most reactive cases. It was found that the reactivity of CYN with chlorine presents a maximum at pH 7 (rate constant of 1265 M(-1)s(-1)). However, the oxidation of CYN with chloramine and permanganate are rather slow processes, with rate constants <1 M(-1)s(-1). The first chlorination product of CYN was found to be 5-chloro-CYN (5-Cl-CYN), which reacts with chlorine 10-20 times slower than the parent compound. The reactivity of ANTX with chlorine and chloramines is also very low (k<1M(-1)s(-1)). The elimination of CYN and ANTX in surface water was also investigated. A chlorine dose of 1.5 mg l(-1) was enough to oxidize CYN almost completely. However, 3 mg l(-1) of chlorine was able to remove only 8% of ANTX, leading to a total formation of trihalomethanes (TTHM) at a concentration of 150 microg l(-1). Therefore, chlorination is a feasible option for CYN degradation during oxidation and disinfection processes but not for ANTX removal. The permanganate dose required for CYN oxidation is very high and not applicable in waterworks.

  6. 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.

  7. 组合氯化消毒工艺的卤代消毒副产物生成特性%Disinfection By-products Reduction of Combined Disinfection by Chlorine and Monochloramines in Distribution System

    Institute of Scientific and Technical Information of China (English)

    刘静; 陈超; 张晓健

    2009-01-01

    比较4种单独使用氯或组合氯化消毒工艺在较长管网停留时的卤代消毒副产物生成情况.4种工艺为单独游离氯消毒、氯胺消毒、清水池游离氯消毒后转氯胺的先氯后氨消毒、短时游离氯后转氯胺的顺序氯化消毒工艺.结果表明,游离氯消毒工艺在管网停留时间长时,卤代消毒副产物会持续大量的生成,而一氯胺消毒工艺生成的卤代消毒副产物量很低.目前使用较为普遍的先氯后氨消毒工艺与游离氯消毒相比,可以降低卤代消毒副产物的生成量,管网停留24 h时,三卤甲烷的生成量降低了9.6%,卤乙酸的生成量减低了42%.但是先氯后氨消毒工艺由于游离氯接触时间约为2 h,卤代消毒副产物已经大量生成.短时游离氯后转氯胺的顺序氯化消毒工艺,由于控制了游离氯的接触时间,可以在保障消毒工艺灭活微生物效果的同时更为有效地控制卤代消毒副产物,管网停留24 h时,三卤甲烷的生成量与单独游离氯消毒工艺相比降低了48%,卤乙酸的生成量减低了72%.因此,顺序氯化消毒工艺可以更好地控制卤代消毒副产物的生成,提高水质安全性.%Halogen disinfection by-products of four chlorined disinfection processes with long contact time in distribution system was compared in the work. These four disinfection processes are free chlorine, monochloramines, free chlorine disinfection in clearwelles while chloramines in distribution system, sequential chlorination disinfection with short-term free chlorine plus chloramines. According to the research, free chlorine generates most trihalomethanes(THMs) and haloacetic acids (HAAs) both in clearwells and distribution system, while monochloramines barely yield halogen DBPs. Free chlorine disinfection in clearwelles while chloramines in distribution system could reduce 9.6% of THMs and 42% of HAAs in 24 h contact time of distribution system compared with free chlorine. But free

  8. An experimental study on (131I-CHIBA-1001: a radioligand for α7 nicotinic acetylcholine receptors.

    Directory of Open Access Journals (Sweden)

    Lei Yin

    Full Text Available OBJECTIVE: The α7 nicotinic acetylcholine receptors (nAChRs play a vital role in the pathophysiology of neuropsychiatric diseases such as Alzheimer's disease and depression. However, there is currently no suitable positron emission tomography (PET or Single-Photon Emission Computed Tomography (SPECT radioligands for imaging α7 nAChRs in brain. Here our aim is to radiosynthesize a novel SPECT radioligand (131I-CHIBA-1001 for whole body biodistribution study and in vivo imaging of α7 nAChRs in brain. METHOD: (131I-CHIBA-1001 was radiosynthesized by chloramine-T method. Different conditions of reaction time and temperature were tested to get a better radiolabeling yield. Radiolabeling yield and radiochemical purities of (131I-CHIBA-1001 were analyzed by thin layer chromatography (TLC and high-performance liquid chromatography (HPLC system. Whole body biodistribution study was performed at different time points post injection of (131I-CHIBA-1001 in KM mice. Monkey subject was used for in vivo SPECT imaging in brain. RESULT: The radiolabeling yield of (131I-CHIBA-1001 reached 96% within 1.5∼2.0 h at 90∼95°C. The radiochemical purity reached more than 99% after HPLC purification. (131I-CHIBA-1001 was highly stable in saline and fresh human serum in room temperature and 37°C separately. The biodistribution data of brain at 15, 30, and 60 min were 11.05±1.04%ID/g, 8.8±0.04%ID/g and 6.28±1.13%ID/g, respectively. In experimental SPECT imaging, the distribution of radioactivity in the brain regions was paralleled with the distribution of α7 nAChRs in the monkey brain. Moreover, in the blocking SPECT imaging study, the selective α7 nAChR agonist SSR180711 blocked the radioactive uptake in the brain successfully. CONCLUSION: The CHIBA-1001 can be successfully radiolabeled with (131I using the chloramine-T method. (131I-CHIBA-1001 can successfully accumulate in the monkey brain and image the α7 acetylcholine receptors. (131I-CHIBA-1001 can be a

  9. Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

    Institute of Scientific and Technical Information of China (English)

    Wang Leilei; Chen Wei; Lin Tao

    2008-01-01

    The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon (GAC) filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 μm in size. The concentration in the GAC effluent (561 particles/mL) was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 μm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 μm and 15 μm increasing. The most probable number (MPN) of carbon fines reached 43 unit/L after six hours and fines between 0.45 μm and 8.0 μm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU (colony-forming units) /mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine (90%) was higher than that with chlorine (70%). Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.

  10. Effects of UV irradiation and UV/chlorine co-exposure on natural organic matter in water

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Zhang, Zaili; Yang, Xin; Xu, Yiyue; Liang, Yongmei, E-mail: liangym@mail.sysu.edu.cn

    2012-01-01

    The effects of co-exposure to ultraviolet (UV) irradiation (with either low- or medium-pressure UV lamps) and free chlorine (chloramine) at practical relevant conditions on changes in natural organic matter (NOM) properties were investigated using four waters. The changes were characterized using the specific disinfection by-product formation potential (SDBPFP), specific total organic halogen formation potential (STOXFP), differential UV absorbance ( Increment UVA), and size-exclusion chromatography (SEC). The results for exposure to UV irradiation alone and for samples with no exposure were also obtained. The SDBPFPs in all UV-irradiated NOM waters observed were higher than those of non-irradiated samples. UV irradiation led to increases in STOXFPs as a result of chlorination, but no changes, or only small decreases, from chloramination. UV irradiation alone led to positive Increment UVA spectra of the four NOM waters; co-exposure to UV and chlorine gave larger negative Increment UVA spectra than those obtained by chlorine exposure alone. No obvious changes in SEC results were observed for samples only irradiated with UV light; co-exposure gave no detectable changes in the abundances of small fractions for exposure to chlorine only. Both UV photooxidation and photocatalytic oxidation appear to affect the reactivity of the NOM toward subsequent chlorination, and the magnitude of the changes is generally greater for medium-pressure lamps than for low-pressure lamps. These results suggest that applying UV disinfection technology to a particular source may not always be disinfection by-product-problem-free, and the interactions between UV light, chlorine, and NOM may need to be considered. - Highlights: Black-Right-Pointing-Pointer We discussed the effects of co-exposure to UV light and chlorine on properties of natural organic matters in waters. Black-Right-Pointing-Pointer UV irradiation led to increases in SDBPFP and STOXFP of NOM waters from chlorination. Black

  11. 水中典型含氮有机物氯化生成消毒副产物的潜能研究%Chlorination Byproducts Formation Potentials of Typical Nitrogenous Organic Compounds in Water

    Institute of Scientific and Technical Information of China (English)

    徐倩; 徐斌; 覃操; 夏圣骥; 高乃云; 田富箱; 李大鹏

    2011-01-01

    选取了受污染原水中广泛存在的12种含氮有机物(除草剂、杀虫剂、氨基酸、工业品等),开展了氯化和氯胺化培养生成典型消毒副产物的实验,目的是通过对水中脲类除草剂、嗪类除草剂和其他含氮化合物培养生成不同消毒副产物的生成量,讨论不同种类含氮化合物生成含碳和含氮消毒副产物规律以及考察不同消毒副产物的可能前体物.研究发现,脲类除草剂经过量氯化和氯胺化可产生多达9种消毒副产物,反应活性最高的绿麦隆可生成三氯甲烷(CF)、一氯乙酸(MCAA)、二氯乙酸(DCAA)、1,1-二氯丙酮(1,1-DCP)、1,1,1-三氯丙酮%Twelve typical nitrogenous organic compounds including herbicides,pesticides,amino acids,industrial products etc in polluted raw water were selected to investigate formation of typical carbonaceous and nitrogenous DBPs during chlorination and chloramination.To indentify the formation mechanism of carbonaceous and nitrogenous disinfection byproducts from nitrogenous chemicals,chlorination and chloroamination of urea herbicides,triazine herbicides,amino acid,and other compounds were investigated.As a result,the potential precursors for different DBPs were defined as well.It has been identified that widely used urea herbicides could produce as many as 9 specific DBPs.The chlorotoluron shows highest reactivity and yields chloroform(CF),monochloroacetic acid(MCAA),dichloroacetic acid(DCAA),1,1-dichloro-acetone(1,1-DCP),1,1,1-trichloro-acetone(1,1,1-TCP),chloropicrin(NTCM),dichloro-acetonitrile(DCAN),dimethylnitrosamine(NDMA).The results indicated that aldicarb and dinoseb are important precursors of CF,DCAA,MCAA,NTCM as well.High concentrations of CF and DCAA were found during L-tryptophan chlorination.Furthermore,DBPs formation pathways and mechanisms were suggested during chlorination and chloramination of chlorotoluron,ametryn,dinoseb L-tryptophan.

  12. Role of taurine in the pathogenesis of obesity.

    Science.gov (United States)

    Murakami, Shigeru

    2015-07-01

    Taurine is a sulfur-containing amino acid that is present in mammalian tissues in millimolar concentrations. Taurine is involved in a diverse array of biological and physiological functions, including bile salt conjugation, osmoregulation, membrane stabilization, calcium modulation, anti-oxidation, and immunomodulation. The prevalence of obesity and being overweight continues to rise worldwide at an alarming rate. Obesity is associated with a higher risk of metabolic and cardiovascular diseases, cancer, and other clinical conditions. Ingestion of taurine has been shown to alleviate metabolic diseases such as hyperlipidemia, diabetes, hypertension, and obesity in animal models. A global epidemiological survey showed that 24-h urinary taurine excretion, as a marker of dietary taurine intake, was inversely associated with BMI, blood pressure, and plasma cholesterol in humans. In addition, taurine chloramine, an endogenous product derived from activated neutrophils, has been reported to suppress obesity-induced oxidative stress and inflammation in adipocytes. Synthetic activity and concentration of taurine in adipose tissues and plasma have been shown to decrease in humans and animals during the development of obesity, suggesting a relationship between taurine deficiency and obesity. In this review, I summarize the effects of taurine on the progression of obesity in animal models and humans. Furthermore, I discuss possible mechanisms underlying the antiobesity effects of taurine.

  13. Synthesis of [{sup 123}I]iodine labelled imidazo[1,2-b] pyridazines as potential probes for the study of peripheral benzodiazepine receptors using SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Katsifis, A.; Mattner, F.; Dikic, B. [Radiopharmaceuticals Div. ANSTO, Menai, NSW (Australia); Barlin, G. [Div. of Neurosciences, John Curtin School of Medical Research, Australian National Univ., Canberra (Australia)

    2004-07-01

    The pyridazines 3-acetamidomethyl-6-chloro-2-(4'-iodophenyl)imidazo[1,2-b]pyridazine 1 (IC{sub 50} = 1.6 nM) and 3-benzamidomethyl-6-iodo-2-(4'-t-butylphenyl)imidazo[1,2-b] pyridazine 2 (IC{sub 50} = 4.2 nM), are high affinity and selective ligands for the peripheral benzodiazepine receptors (PBR) compared to the central benzodiazepine counterparts. The [{sup 123}I]1 and [{sup 123}I]2 labelled analogues of these compounds were subsequently synthesised for the potential study of the PBR in vivo using SPECT. Radioiodination of [{sup 123}I]1 was achieved by iododestannylation of the corresponding tributyl tin precursor with Na[{sup 123}I] in the presence of peracetic acid or chloramine-T and the product isolated by C-18 RP HPLC. Radioiodination of [{sup 123}I]2 was achieved by copper assisted bromine [{sup 123}I]iodine exchange of the corresponding bromo precursor in the presence of acetic acid and sodium bisulfate as reducing agent at 200 C. Purification of the crude products were achieved by semi-preparative C-18 RP HPLC to give the products in radiochemical yields > 90%. The products were obtained in > 97% chemical and radiochemical purity and with specific activities > 180 GBq/{mu}mol. (orig.)

  14. Bromine-76 and carbon-11 labelled NNC 13-8199, metabolically stable benzodiazepine receptor agonists as radioligands for positron emission tomography (PET)

    Energy Technology Data Exchange (ETDEWEB)

    Foged, C. [Karolinska Institutet, Department of Clinical Neuroscience, Psychiatry Section, Karolinska Hospital, Stockholm (Sweden)]|[Novo Nordisk A/S, Health Care Discovery and Development, Maaloev (Denmark); Halldin, C.; Pauli, S.; Suhara, T.; Swahn, C.G.; Karlsson, P.; Farde, L. [Karolinska Institutet, Department of Clinical Neuroscience, Psychiatry Section, Karolinska Hospital, Stockholm (Sweden); Loc`h, C.; Maziere, B.; Maziere, M. [Service Hospitalier Frederic Joliot, CEA, Orsay (France); Hansen, H.C. [Novo Nordisk A/S, Health Care Discovery and Development, Maaloev (Denmark)

    1997-10-01

    NNC 13-8241 has recently been labelled with iodine-123 and developed as a metabolically stable benzodiazepine receptor ligand for single-photon emission computed tomography (SPECT) in monkeys and man. NNC 13-8199 is a bromo-analogue of NNC 13-8241. This partial agonist binds selectively and with subnanomolar affinity to the benzodiazepine receptors. We prepared {sup 76}Br labelled NNC 13-8199 from the trimethyltin precursor by the chloramine-T method. Carbon-11 labelled NNC 13-8199 was synthesised by N-alkylation of the nitrogen of the amide group with [{sup 11}C]methyl iodide. Positron emission tomography (PET) examination with the two radioligands in monkeys demonstrated a high uptake of radioactivity in the occipital, temporal and frontal cortex. In the study with [{sup 76}Br]NNC 13-8199, the monkey brain uptake continued to increase until the time of displacement with flumazenil at 215 min after injection. For both radioligands the radioactivity in the cortical brain regions was markedly reduced after displacement with flumazenil. More than 98% of the radioactivity in monkey plasma represented unchanged radioligand 40 min after injection. The low degree of metabolism indicates that NNC 13-8199 is metabolically much more stable than hitherto developed PET radioligands for imaging of benzodiazepine receptors in the primate brain. [{sup 76}Br]NNC 13-8199 has potential as a radioligand in human PET studies using models where a slow metabolism is an advantage. (orig.) With 8 figs., 28 refs.

  15. 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.

  16. Occurrence of carboxylic acids in different steps of two drinking-water treatment plants using different disinfectants.

    Science.gov (United States)

    Jurado-Sánchez, Beatriz; Ballesteros, Evaristo; Gallego, Mercedes

    2014-03-15

    The occurrence of 35 aliphatic and aromatic carboxylic acids within two full scale drinking-water treatment plants was evaluated for the first time in this research. At the intake of each plant (raw water), the occurrence of carboxylic acids varied according to the quality of the water source although in both cases 13 acids were detected at average concentrations of 6.9 and 4.7 μg/L (in winter). In the following steps in each treatment plant, the concentration patterns of these compounds differed depending on the type of disinfectant applied. Thus, after disinfection by chloramination, the levels of the acids remained almost constant (average concentration, 6.3 μg/L) and four new acids were formed (butyric, 2-methylbutyric, 3-hydroxybenzoic and 2-nitrobenzoic) at low levels (1.1-5 μg/L). When ozonation/chlorination was used, the total concentration of the carboxylic acids in the raw water sample (4.7 μg/L) increased up to 6 times (average concentration, 26.3 μg/L) after disinfection and 6 new acids (mainly aromatic) were produced at high levels (3.5-100 μg/L). Seasonal variations of the carboxylic acids under study showed that in both plants, maximum levels of all the analytes were reached in the coldest months (autumn and winter), aromatic acids only being found in those seasons.

  17. Removal of the cyanotoxin anatoxin-a by drinking water treatment processes: a review.

    Science.gov (United States)

    Vlad, Silvia; Anderson, William B; Peldszus, Sigrid; Huck, Peter M

    2014-12-01

    Anatoxin-a (ANTX-a) is a potent alkaloid neurotoxin, produced by several species of cyanobacteria and detected throughout the world. The presence of cyanotoxins, including ANTX-a, in drinking water sources is a potential risk to public health. This article presents a thorough examination of the cumulative body of research on the use of drinking water treatment technologies for extracellular ANTX-a removal, focusing on providing an analysis of the specific operating parameters required for effective treatment and on compiling a series of best-practice recommendations for owners and operators of systems impacted by this cyanotoxin. Of the oxidants used in drinking water treatment, chlorine-based processes (chlorine, chloramines and chlorine dioxide) have been shown to be ineffective for ANTX-a treatment, while ozone, advanced oxidation processes and permanganate can be successful. High-pressure membrane filtration (nanofiltration and reverse osmosis) is likely effective, while adsorption and biofiltration may be effective but further investigation into the implementation of these processes is necessary. Given the lack of full-scale verification, a multiple-barrier approach is recommended, employing a combination of chemical and non-chemical processes.

  18. Development of a radioiodinated ligand for characterising. cap alpha. /sub 1/-adrenoceptors. [Pentolamine and 2 BETA-(4-hydroxyphenyl)-ethylaminomethyl)-tetralone

    Energy Technology Data Exchange (ETDEWEB)

    Adams, A.; Jarrott, B.

    1982-03-15

    Two ..cap alpha..-adrenoceptor antagonists, phentolamine and 2-(..beta..-(4-hydroxyphenyl)-ethylaminomethyl)-tetralone (BE 2254) which are phenolic derivatives were radioiodinated after chloramine-T oxidation of Na/sup 125/I and the labelled material isolated by chromatography. /sup 125/I-Phentolamine does not bind selectively to ..cap alpha..-adrenoceptors in guinea pig brain whereas the /sup 125/I-BE 2254 derivative binds rapidly, reversibly and with high affinity to these receptors with a K/sub d/ of 230 pM. At low concentrations of /sup 125/I-BE 2254 (< 100 pM) approx. 90% of the bound radioligand is specifically bound and under these conditions drug displacement studies show that the ligand binds predominantly to the ..cap alpha../sub 1/ subclass of adrenoceptors. Binding measurements to kidney and smooth muscle membrane preparations indicate that /sup 125/I-BE 2254 may also be a useful tool in the study of ..cap alpha..-adrenoceptors in peripheral tissues. The high specific activity of /sup 125/I-BE 2254 permits the use of minimal quantities of membrane material for receptor assay and ligand displacement measurements, e.g. 250 ..mu..g per assay tube, and this provides a significant advantage over the use of existing radioligands such as /sup 3/H-prazosin which requires approx. 40 times as much tissue.

  19. Selective reactivity of monochloramine with extracellular matrix components affects the disinfection of biofilm and detached clusters.

    Science.gov (United States)

    Xue, Zheng; Lee, Woo Hyoung; Coburn, Kimberly M; Seo, Youngwoo

    2014-04-01

    The efficiency of monochloramine disinfection was dependent on the quantity and composition of extracellular polymeric substances (EPS) in biofilms, as monochloramine has a selective reactivity with proteins over polysaccharides. Biofilms with protein-based (Pseudomonas putida) and polysaccharide based EPS (Pseudomonas aeruginosa), as well as biofilms with varied amount of polysaccharide EPS (wild-type and mutant P. aeruginosa), were compared. The different reactivity of EPS components with monochloramine influenced disinfectant penetration, biofilm inactivation, as well as the viability of detached clusters. Monochloramine transport profiling measured by a chloramine-sensitive microelectrode revealed a broader diffusion boundary layer between bulk and biofilm surface in the P. putida biofilm compared to those of P. aeruginosa biofilms. The reaction with proteins in P. putida EPS multiplied both the time and the monochloramine mass required to achieve a full biofilm penetration. Cell viability in biofilms was also spatially influenced by monochloramine diffusion and reaction within biofilms, showing a lower survival in the surface section and a higher persistence in the middle section of the P. putida biofilm compared to the P. aeruginosa biofilms. While polysaccharide EPS promoted biofilm cell viability by obstructing monochloramine reactive sites on bacterial cells, protein EPS hindered monochloramine penetration by reacting with monochloramine and reduced its concentration within biofilms. Furthermore, the persistence of bacterial cells detached from biofilm (over 70% for P. putida and ∼40% for polysaccharide producing P. aeruginosa) suggested that currently recommended monochloramine residual levels may underestimate the risk of water quality deterioration caused by biofilm detachment.

  20. Pathological and electron microscopic studies on cold water disease among cultured rainbow trout (Oncorhynchus Mykiss Walbaum

    Directory of Open Access Journals (Sweden)

    Salah Mesalhy Aly

    2013-07-01

    Full Text Available The present study aims to investigate the etiology and pathogenesis of cold water disease among cultured rainbow trout (Oncorhynchus Mykiss Walbaum reared at low water temperature on a private farm, and propose preventive and control measures to prevent the recurrence of the disease and its spread to the neighboring farms or to other countries. The disease is caused by Flavobacterium psychrophilum and is characterized clinically by high mortality rates (25% with necrotizing skin and fin lesions. Septicemia with muscular and gill involvement is observed in severely affected cases. The histopathological and ultrastructure alterations in the infected trout explain the pathogencity of this microorganism in many organs other than skin and fins either directly by these bacteria or by its extracellular products, or indirectly via the hypoxia and ion imbalance that results from skin and gill damage. Although some antibiotics, such as trimethoprime, chloramin T and oxytetracycline, are effective on the causative agent, improvement in water quality, vaccination, increasing fish resistance and strict hygiene as well as quarantine measures would all help.

  1. Differential effects on innate versus adaptive immune responses by WF10.

    Science.gov (United States)

    Giese, Thomas; McGrath, Michael S; Stumm, Susanne; Schempp, Harald; Elstner, Erich; Meuer, Stefan C

    2004-06-01

    Oxidative compounds that are physiologically generated in vivo can induce natural defense mechanisms to enhance the elimination of pathogens and to limit inflammatory tissue damage in the course of inflammation. Here, we have investigated WF10, a chlorite-based non-toxic compound for its functional activities on human PBMC in vitro. WF10 exerts potent immune-modulatory effects through generating endogenous oxidative compounds such as taurine chloramine. Proliferation and IL-2 production of anti-CD3 stimulated PBMC were inhibited by WF10, as was the nuclear translocation of the transcription factor NFATc. In PBMC and monocytes, however, WF10 induced pro-inflammatory cytokines like IL-1beta, IL-8, and TNF-alpha. In the monocytic cell line THP-1, the activation of the transcription factors AP-1 and NFkappaB by WF10 was demonstrated. Inhibition of NFAT regulated genes in activated lymphocytes in concert with the induction of several myeloid cell associated pro-inflammatory genes in monocytes represents a novel mechanism of immune modulation.

  2. Kinetics and mechanism of dimethoate chlorination during drinking water treatment.

    Science.gov (United States)

    Tian, Fang; Liu, Wenjun; Guo, Guang; Qiang, Zhimin; Zhang, Can

    2014-05-01

    Dimethoate (DMT), a commonly used organophosphorus pesticide, is of great concern because of its toxicity and potentially harmful effects on water sources. The elimination of DMT as well as the toxicity and persistence of the byproducts formed during DMT degradation is most important for the safety of drinking water. This study first determined the reaction kinetics of DMT with free chlorine (FC) under typical water treatment conditions. The reaction between DMT and FC proceeded rapidly, exhibiting first-order with respect to each reactant. The degradation of DMT by FC was highly pH dependent, and the pseudo-first-order rate constant decreased obviously from 0.13 to 0.02 s(-1) with an increase in pH from 7.0 to 8.3. Bromide ion accelerated the reaction by acting as a catalyst, and the accelerated reaction rate was linearly proportional to the bromide concentration. As a ubiquitous component in natural waters, humic acid also increased the reaction rate. However, the presence of ammonium inhibited the degradation of DMT due to its rapid converting FC to chloramines. Omethoate (OMT) was identified as an important byproduct of DMT chlorination, but only accounted for ca. 28% of the DMT degraded; and other two organic byproducts were also identified. The acute toxicity of DMT solution increased after treatment with FC due to the formation of more toxic byproducts (e.g. OMT).

  3. Preparation, purification and primary bioevaluation of radioiodinated ofloxacin. An imaging agent

    Energy Technology Data Exchange (ETDEWEB)

    Kandil, Shaban; Seddik, Usama; Hussien, Hiba; Shaltot, Mohamed [Atomic Energy Authority, Cairo (Egypt). Cyclotron Project; El-Tabl, Abdou [Monofia Univ. (Egypt). Faculty of Science

    2015-07-01

    The broad-spectrum antibiotic agents have been demonstrated as promising diagnostic tools for early detection of infectious lesions. We set out ofloxacin (Oflo), a second-generation fluoroquinolone, for the radioiodination process. In particular, this was carried out with {sup 125}I via an electrophilic substitution reaction. The radiochemical yield was influenced by different factors; drug concentration, different oxidizing agents, e.g. chloramine-T, iodogen and n-bromosuccinimide, pH of medium, reaction time, temperature and different organic media. These parameters were studied to optimize the best conditions for labeling with ofloxacin. We found that radiolabeling in ethanol medium showed a 70% radiochemical yield of {sup 125}I-ofloxacin. The radioiodination was determined by means of TLC and HPLC. The cold labeled Oflo ({sup 127}I-Oflo) was prepared and controlled by HPLC. The cold labeled Oflo was also confirmed by NMR and MS techniques. Furthermore, biodistribution studies for labeled {sup 125}I-Oflo were examined in two independent groups (3 mice in each one); control and E. Coli-injected (inflamed). The radiotracer showed a good localization in muscle of thigh for inflamed group as compared to control. In conclusion, ofloxacine might be a promising target as an anti-inflammatory imaging agent.

  4. Serum prostate-specific acid phosphatase: development and validation of a specific radioimmunoassay. [/sup 125/I tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Vihko, P.; Sajanti, E.; Jaenne, O.; Peltonen, L.; Vihko, R.

    1978-11-01

    We describe radioimmunoassay for human prostatic acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) in serum, with use of monospecific antisera raised in rabbits against highly purified acid phosphatase from human prostates. The antiserum did not cross react with partly purified acid phosphatases from human spleen, erythrocytes, or synovial tissues. /sup 125/I-labeled acid phosphatase was prepared by a Chloramine T method, and the bound and free antigen was separated in the assay by use of anti-rabbit gamma-globulin raised in sheep. Uniform low nonspecific binding of the (/sup 125/I)acid phosphatase was achieved by using acid-phosphatase-free serum to prepare standard curves and diluted samples of serum with high acid phosphatase activities. Concentrations of immunoreactive acid phosphatase in the serum of healthy men ranged from <1 to 10 ..mu..g/liter and for 12 patients with advanced prostatic carcinoma between 100 and 500 ..mu..g/liter. The concentrations of the enzyme in sera of patients with benign prostatic hyperplasia were very similar to those in sera of the reference group.

  5. Sample Enrichment for Bioanalytical Assessment of Disinfected Drinking Water: Concentrating the Polar, the Volatiles, and the Unknowns.

    Science.gov (United States)

    Stalter, Daniel; Peters, Leon I; O'Malley, Elissa; Tang, Janet Yat-Man; Revalor, Marion; Farré, Maria José; Watson, Kalinda; von Gunten, Urs; Escher, Beate I

    2016-06-21

    Enrichment methods used in sample preparation for the bioanalytical assessment of disinfected drinking water result in the loss of volatile and hydrophilic disinfection byproducts (DBPs) and hence likely tend to underestimate biological effects. We developed and evaluated methods that are compatible with bioassays, for extracting nonvolatile and volatile DBPs from chlorinated and chloraminated drinking water to minimize the loss of analytes. For nonvolatile DBPs, solid-phase extraction (SPE) with TELOS ENV as solid phase performed superior compared to ten other sorbents. SPE yielded >70% recovery of nonpurgeable adsorbable organic halogens (AOX). For volatile DBPs, cryogenic vacuum distillation performed unsatisfactorily. Purge and cold-trap with crushed ice serving as condensation nuclei achieved recoveries of 50-100% for trihalomethanes and haloacetonitriles and approximately 60-90% for purged AOX from tap water. We compared the purgeable versus the nonpurgeable fraction by combining purge-and-trap extraction with SPE. The purgeable DBP fraction enriched with the purge-and-trap method exerted a lower oxidative stress response in mammalian cells than the nonpurgeable DBPs enriched with SPE after purging, while contributions of both fractions to bacterial cytotoxicity was more variable. 37 quantified DBPs explained almost the entire AOX in the purge-and-trap extracts, but <16% in the SPE extracts demonstrating that the nonpurgeable fraction is dominated by unknown DBPs.

  6. Fetal antigen 2: an amniotic protein identified as the aminopropeptide of the alpha 1 chain of human procollagen type I

    DEFF Research Database (Denmark)

    Teisner, B; Rasmussen, H B; Højrup, P;

    1992-01-01

    Fetal antigen (FA2) was purified from second trimester human amniotic fluid by immunospecific chromatography, gel filtration and reversed-phase chromatography. Gel filtration revealed two molecular forms of FA2 eluting at volumes corresponding to an M(r) of approximately 100 kDa and 30 kDa. SDS-P...... to that of FA2 in human skin. FA2 is a circulating form of the aminopropeptide of the alpha 1 chain of procollagen type I, and this is the first description of its isolation and structural characterization in humans. Udgivelsesdato: 1992-Dec...... with the aminopropeptide of the alpha 1 chain of human procollagen type I as determined by nucleotide sequences. After oxidative procedures normally employed for radio-iodination (iodogen and chloramine-T), FA2 lost its immunoreactivity. An antigen which cross-reacted with polyclonal rabbit anti-human FA2 was demonstrated...... in fetal calf serum. Gel filtration with analysis of fractions by inhibition ELISA showed that the bovine homologue was present in the same molecular forms as those in human amniotic fluid, and immunohistochemical analysis with anti-human FA2 showed that its distribution in bovine skin was identical...

  7. Photolytic removal of DBPs by medium pressure UV in swimming pool water.

    Science.gov (United States)

    Hansen, Kamilla M S; Zortea, Raissa; Piketty, Aurelia; Vega, Sergio Rodriguez; Andersen, Henrik Rasmus

    2013-01-15

    Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020 min(-1) for chloroform to 0.523 min(-1) for trichloronitromethane. The rate constants generally increased with bromine substitution. Using the UV removal of combined chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34 kWh m(-3) d(-1) and the UV dose required to removed 90% of trichloronitromethane was 0.4 kWh m(-3) d(-1), while 2.6 kWh m(-3) d(-1) was required for chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes ranged from 0.6 to 3.1 kWh m(-3) d(-1). It was predicted thus that a beneficial side-effect of applying UV for removing combined chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes.

  8. Studies on the mode of action of calciferol. XIII. Development of a radioimmunoassay for vitamin D-dependent chick intestinal calcium-binding protein and tissue distribution

    Energy Technology Data Exchange (ETDEWEB)

    Christakos, S.; Friedlander, E.J.; Frandsen, B.R.; Norman, A.W.

    1979-05-01

    A RIA for chick intestinal calcium-binding protein (CaBP) has been developed with a sensitivity of 1 ng. The antiserum was generated in rabbits injected with highly purified vitamin D-dependent chick intestinal CaBP. The assay employs the double antibody technique, and /sup 125/I-labeled CaBP was prepared using chloramine T. Low molecular weight peptide hormones and normal rabbit, rat, and human serum proteins show no cross-reactivity in the assay. Measurements of chick intestinal and kidney CaBP by RIA showed a good correlation with measurements of CaBP by the radial immunodiffusion method. The assay is reproducible (interassay variability, 16.3%) and precise (intraassay variability, 4.0%). The concentration of immunoreactive CaBP (iCaBP) in chick serum (2.7 ng/ml serum) can now be measured as early as 8 h after the administration of 6.5 nmol 1,25-dihydroxyvitamin D/sub 3/; a maximum of 11 ng/ml is reached at 20 h. The level of CaBP in chick serum was found to be dependent on the dose of vitamin D/sub 3/ or 1,25-dihydroxyvitamin D/sub 3/ administered to the animal.

  9. Performance evaluation of the UV/H2O2 process on selected nitrogenous organic compounds: reductions of organic contents vs. corresponding C-, N-DBPs formations.

    Science.gov (United States)

    Chen, Huei-Wen; Chen, Chia-Yang; Wang, Gen-Shuh

    2011-10-01

    The presence of various organic contaminants in water sources is of concern due to their direct threats to human health and potential to react with disinfectants to form carcinogenic byproducts including trihalomethanes, haloacetic acids and nitrosamines in finished water. This study applied both medium-pressure and low-pressure ultraviolet light coupled with hydrogen peroxide (UV/H2O2) to evaluate its efficacy for degradation of selected nitrogenous organic compounds and corresponding disinfection byproduct (DBP) formation. Six organic compounds were chosen as target precursors based on their nitrogen contents and molecular structures. The results showed that higher oxidation capacity resulted in better reduction of organic matters and DBP formation potentials (DBPFPs). However, insufficient contact time and oxidant doses could lead to a rise of DBPFPs in the early stages of UV/H2O2 reactions. A greater percentage removal was achieved for organic carbon than organic nitrogen after UV/H2O2 treatment, especially for compounds with complicated structure such as diltiazem. During the UV/H2O2 treatment, the intermediate products include tertiary amine, dimethyl amine (DMA) or DMA-like structures, which are N-nitrosodimethylamine (NDMA) precursors after chlorination or chloramination. Furthermore, it was observed that using dissolved organic nitrogen and DMA to predict NDMAFP could lead to biased conclusions because of the complex nature of nitrogenous matters in aqueous environments.

  10. Disinfection by-product formation during seawater desalination: A review.

    Science.gov (United States)

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water.

  11. Clinical scale preparation and evaluation of {sup 131}I-Rituximab for Non-Hodgkin's lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Kameswaran, Mythili; Vimalnath, K. Viswanathan; Rajeswari, Ardhi; Joshi, Prahlad Vasudeo; Samuel, Grace [Bhabha Atomic Research Centre, Mumbai (India). Radiopharmaceuticals Div.; Sarma, H.D. [Bhabha Atomic Research Centre, Mumbai (India). Radiation Biology and Health Sciences Div.

    2014-09-01

    Radioimmunotherapy (RIT) with anti CD20 MoAb conjugated to a β{sup -} emitting radioisotope like {sup 131}I or {sup 90}Y has the added advantage of delivering radiation not only to tumor cells that bind the antibody but also due to a crossfire effect, to neighboring tumor cells inaccessible to the antibody. In order to make available an indigenous radioimmunotherapeutic agent for Non Hodgkin's Lymphoma (NHL), radioiodinated Rituximab has been prepared and evaluated at a clinical scale. Radioiodination of Rituximab was performed by the conventional Chloramine T method using 7.4 GBq Na{sup 131}I in a lead shielded plant. Six batches of radioiodination were prepared and characterized by electrophoresis and HPLC to evaluate the reproducibility of the product. The product remained stable retaining the radiochemical purity > 95% upto 5 days after radioiodination. In vitro cell binding studies and biodistribution studies in normal Swiss mice have indicated the potential of this molecule as a radioimmunotherapeutic agent for NHL. (orig.)

  12. Sporicidal/bactericidal textiles via the chlorination of silk.

    Science.gov (United States)

    Dickerson, Matthew B; Lyon, Wanda; Gruner, William E; Mirau, Peter A; Slocik, Joseph M; Naik, Rajesh R

    2012-03-01

    Bacterial spores, such as those of the Bacillus genus, are extremely resilient, being able to germinate into metabolically active cells after withstanding harsh environmental conditions or aggressive chemical treatments. The toughness of the bacterial spore in combination with the use of spores, such as those of Bacillus anthracis, as a biological warfare agent necessitates the development of new antimicrobial textiles. In this work, a route to the production of fabrics that kill bacterial spores and cells within minutes of exposure is described. Utilizing this facile process, unmodified silk cloth is reacted with a diluted bleach solution, rinsed with water, and dried. The chlorination of silk was explored under basic (pH 11) and slightly acidic (pH 5) conditions. Chloramine-silk textiles prepared in acidified bleach solutions were found to have superior breaking strength and higher oxidative Cl contents than those prepared under caustic conditions. Silk cloth chlorinated for ≥1 h at pH 5 was determined to induce >99.99996% reduction in the colony forming units of Escherichia coli, as well as Bacillus thuringiensis Al Hakam (B. anthracis simulant) spores and cells within 10 min of contact. The processing conditions presented for silk fabric in this study are highly expeditionary, allowing for the on-site production of protein-based antimicrobial materials from a variety of agriculturally produced feed-stocks.

  13. Luminal oxidants selectively modulate electrogenic ion transport in rat colon

    Institute of Scientific and Technical Information of China (English)

    Julio M Mayol; Yolanda Adame-Navarrete; Pilar Alarma-Estrany; Elena Molina-Roldan; Fernando Huete-Toral; Jesus A Fernandez-Represa

    2006-01-01

    AIM: To investigate the effects of luminal exposure to H2O2 and two related thiol oxidizing agents on basal and stimulated chloride secretion in native colon using electrophysiological and pharmacological approaches.METHODS: Unstripped rat distal colon segments were mounted in Ussing chambers. Potential difference, cal culated resistance and short-circuit current across unstripped colon segments were monitored with a dual voltage/current clamp. Paracellular permeability was assessed by measuring the mucosa-to-serosa flux of a fluorescent probe (FITC).RESULTS: Luminal exposure to hydrogen peroxide transitorily stimulated chloride secretion without altering barrier function. This stimulatory effect could be blocked by basolateral atropine but not indomethacin. The cysteine and methionine oxidizing compounds, phenylarsine oxide and chloramine T respectively, mimicked the effect of H2O2, except for a drop in transcolonic resistance after 30 min. In contrast to the observed stimulatory effect on basal secretion, cAMP-stimulated electrogenic ion trans port was blunted by luminal H2O2. However, the Ca2+-activated response remained unchanged.CONCLUSION: H2O2 may be an important selective modulator of intestinal ion and water secretion in certain pathologic conditions such as inflammation or ischemiareperfusion by multiple mechanisms.

  14. Factors Affecting Bacterial Growth in Drinking Water Distribution System

    Institute of Scientific and Technical Information of China (English)

    WEI LU; XIAO-JIAN ZHANG

    2005-01-01

    Objective To define the influence of some parameters, including assimilable organic carbon (AOC), chloramine residual, etc. on the bacterial growth in drinking water distribution systems. Methods Three typical water treatment plants in a northern city (City T) of China and their corresponding distribution systems were investigated. Some parameters of the water samples, such as heterotrophic plate content (HPC), AOC, CODMn, TOC, and phosphate were measured. Results The AOC in most water samples were more than 100 μg/L, or even more than 200 μg/L in some cases. The HPC in distribution systems increased significantly with the decrease of residual chlorine. When the residual chlorine was less than 0.1 mg/L, the magnitude order of HPC was 104 CFU/mL; when it was 0.5-0.7 mg/L, the HPC was about 500 CFU/mL. Conclusion For controlling the biostability of drinking water, the controlling of AOC and residual chlorine should be considered simultaneously. The influence of phosphors on the AOC tests of water is not significant. Phosphors may not be the limiting nutrient in the water distribution systems.

  15. Increased concentrations of breath haloamines are not detectable in airways inflammation using SIFT-MS.

    Science.gov (United States)

    Storer, Malina K; Dummer, Jack D; Cook, Julie; McEwan, Murray; Epton, Michael J

    2011-09-01

    The haloamines, including the chloramines (H(2)NCl, HNCl(2)) and bromamine (H(2)NBr), are diffusible gases that are likely to be produced during inflammation and so may be present as markers of lung inflammation on breath. Although haloamines are quite reactive, it is possible to measure these compounds in humid samples using SIFT-MS. Until recently the quantification of haloamines in breath suffered from interference from other common breath compounds. This was overcome by heating the flow tube which removed major water cluster product ions. Despite the improvements to the method, previous attempts to measure the haloamines in breath samples from normal volunteers had found no evidence to support their presence. Since it is proposed that the haloamines may be present in higher concentrations during airways inflammation we have attempted to detect the compounds in the exhaled breath of patients with airways inflammatory conditions. On-line and off-line breath samples were analyzed; however, there was no discernable change to any of product ions when compared to ambient air or normal subjects. This suggests that despite sensitivity in the mid part per trillion range haloamines are not significantly raised in airways inflammation.

  16. Effect of oxidant exposure on the release of intracellular microcystin, MIB, and geosmin from three cyanobacteria species.

    Science.gov (United States)

    Wert, Eric C; Korak, Julie A; Trenholm, Rebecca A; Rosario-Ortiz, Fernando L

    2014-04-01

    The release of intracellular microcystin-LR (MC-LR), 2-methylisoborneol (MIB), and geosmin was investigated after the oxidation of three cyanobacteria (Microcystis aeruginosa (MA), Oscillatoria sp. (OSC), and Lyngbya sp. (LYN)). During the oxidation of 200,000 cells/mL of MA, release of intracellular MC-LR exceeded the World Health Organization (WHO) guideline of 1 μg/L during the lowest oxidant exposures (CT) tested: ozone (0 mg-min/L, below the ozone demand), chlorine (geosmin exceeded reported threshold odor values after exposure to chlorine, chlorine dioxide, and chloramine, which have low reactivity with these taste and odor compounds. Ozone oxidation of OSC yielded an increase in MIB concentration at lower exposures (≤2.9 mg-min/L), likely due to insufficient oxidation by hydroxyl radicals. The release of intracellular organic matter (IOM) was also measured to determine the potential of bulk measurements to act as a surrogate for cyanotoxins and metabolite release. In all cases, the dissolved organic carbon (DOC) release was less than 0.25 mgC/L, which lacked the sensitivity to indicate the release of MC-LR, MIB, or geosmin. The fluorescence index proved to be a more sensitive indicator of intracellular organic matter release than DOC for MA. These results illustrate that toxic or odorous compounds may be released from cyanobacteria cells during oxidation processes with minimal changes in the DOC concentration.

  17. Formation of disinfection by-products after pre-oxidation with chlorine dioxide or ferrate.

    Science.gov (United States)

    Yang, Xin; Guo, Wanhong; Zhang, Xing; Chen, Feng; Ye, Tingjin; Liu, Wei

    2013-10-01

    The effect of pre-oxidation with chlorine dioxide (ClO2) or ferrate (Fe(VI)) on the formation of disinfection by-products (DBPs) during chlorination or chloramination was tested with natural waters from 12 sources (9 surface waters, 1 groundwater, and 2 wastewater effluents). DBPs investigated included trihalomethanes (THM), chloral hydrate (CH), haloketones (HK), haloacetonitriles (HAN) and trichloronitromethane (TCNM), chlorite and chlorate. Chlorite and chlorate were found in the ClO2-treated waters. Application of 1 mg/L ClO2 ahead of chlorination reduced the formation potential for THM by up to 45% and the formation of HK, HAN and TCNM in most of the samples. The CH formation results were mixed. The formation of CH and HK was enhanced with low doses of Fe(VI) (1 mg/L as Fe), but was greatly reduced at higher doses (20 mg/L Fe). Fe(VI) reduced the formation of THM, HAN and TCNM in most of the samples. Reduced potential for the formation of NDMA was observed in most of the samples after both ClO2 and Fe(VI) pre-oxidation.

  18. N-Nitrosamines and halogenated disinfection byproducts in U.S. Full Advanced Treatment trains for potable reuse.

    Science.gov (United States)

    Zeng, Teng; Plewa, Michael J; Mitch, William A

    2016-09-15

    Water utilities are increasingly considering indirect and direct potable reuse of municipal wastewater effluents. Disinfection byproducts (DBPs), particularly N-nitrosamines, are key contaminants of potential health concern for potable reuse. This study quantified the concentrations of N-nitrosamines and a suite of regulated and unregulated halogenated DBPs across five U.S. potable reuse Full Advanced Treatment trains incorporating microfiltration, reverse osmosis, and UV-based advanced oxidation. Low μg/L concentrations of trihalomethanes, haloacetic acids, dichloroacetonitrile, and dichloroacetamide were detected in the secondary or tertiary wastewater effluents serving as influents to potable reuse treatment trains, while the concentrations of N-nitrosamines were more variable (e.g., trains. Reverse osmosis rejected DBPs to varying degrees, ranging from low for some (e.g., N-nitrosamines, trihalomethanes, and haloacetonitriles) to high for other DBPs. UV-based advanced oxidation eliminated N-nitrosamines, but only partially removed halogenated DBPs. Chloramination of the treatment train product waters under simulated distribution system conditions formed additional DBPs, with concentrations often equaling or exceeding those in the treatment train influents. Overall, the concentration profiles of DBPs were fairly consistent within individual treatment trains for sampling campaigns separated by months and across different treatment trains for the same sampling time window. Weighting DBP concentrations by their toxic potencies highlighted the potential significance of haloacetonitriles, which were not effectively removed by reverse osmosis and advanced oxidation, to the DBP-associated toxicity in potable reuse waters.

  19. {sup 99m}Tc-labeled chimeric anti-NCA 95 antigranulocyte monoclonal antibody for bone marrow imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sarwar, M.; Higuchi, Tetsuya; Tomiyoshi, Katsumi [Gunma Univ., Maebashi (Japan). School of Medicine] [and others

    1998-09-01

    Chimeric mouse-human antigranulocyte monoclonal antibody (ch MAb) against non-specific cross-reacting antigen (NCA-95) was labeled with {sup 99m}Tc (using a direct method) and {sup 125}I (using the chloramine T method), and its binding to human granulocytes and LS-180 colorectal carcinoma cells expressing carcinoembryonic antigen on their surfaces, cross-reactive with anti-NCA-95 chimeric monoclonal antibody, increased in proportion to the number of cells added and reached more than 80% and 90%, respectively. In biodistribution studies, {sup 99m}Tc and {sup 125}I-labeled ch anti-NCA-95 MAb revealed high tumor uptake, and the tumor-to-blood ratio was 2.9 after 24 hours. The tumor-to-normal-organ ratio was also more than 3.0 in all organs except for the tumor-to-kidney ratio. Scintigrams of athymic nude mice confirmed the results of biodistribution studies that showed higher radioactivity in tumor and kidney of the mice administered with {sup 99m}Tc-labeled ch MAb. A normal volunteer injected with {sup 99m}Tc-labeled ch anti-NCA-95 antigranulocyte MAb showed clear bone marrow images, and a patient with aplastic anemia revealed irregular uptake in his lumbar spine, suggesting its utility for bone marrow scintigraphy and for the detection of hematological disorders, infections, and bone metastasis. (author)

  20. Managing risks from virus intrusion into water distribution systems due to pressure transients.

    Science.gov (United States)

    Yang, Jian; LeChevallier, Mark W; Teunis, Peter F M; Xu, Minhua

    2011-06-01

    Low or negative pressure transients in water distribution systems, caused by unexpected events (e.g. power outages) or routine operation/maintenance activities, are usually brief and thus are rarely monitored or alarmed. Previous studies have shown connections between negative pressure events in water distribution systems and potential public health consequences. Using a quantitative microbial risk assessment (QMRA) model previously developed, various factors driving the risk of viral infection from intrusion were evaluated, including virus concentrations external to the distribution system, maintenance of a disinfectant residual, leak orifice sizes, the duration and the number of nodes drawing negative pressures. The most sensitive factors were the duration and the number of nodes drawing negative pressures, indicating that mitigation practices should be targeted to alleviate the severity of low/negative pressure transients. Maintaining a free chlorine residual of 0.2 mg/L or above is the last defense against the risk of viral infection due to negative pressure transients. Maintaining a chloramine residual did not appear to significantly reduce the risk. The effectiveness of ensuring separation distances from sewer mains to reduce the risk of infection may be system-specific. Leak detection/repair and cross-connection control should be prioritized in areas vulnerable to negative pressure transients.

  1. Application of different /sup 125/I tracers in radioimmunoassays of estradiol-17. beta

    Energy Technology Data Exchange (ETDEWEB)

    Bienert, R.; Flentje, H.; Herzmann, H. (Akademie der Wissenschaften der DDR, Berlin-Buch. Zentralinstitut fuer Isotopen- und Strahlenforschung; Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung)

    1984-01-01

    Some different /sup 125/I-labelled estradiol tracers were produced by direct radioiodizing of estradiol and also of the histamine and tyramine conjugates of estradiol-3-carboxymethylether (E/sub 2/-3-CM) by means of the chloramine-T method. The linkage properties of these tracers were investigated in relation to the /sup 3/H-labelled estradiol opposite to the antisera, which were produced against the cow serum albumin (RSA) conjugates of E/sub 2/-3-CM and estradiol-6-carboxymethyloxime (E/sub 2/-6-CMO). As suitable system for the radioimmunological estradiol determination could be revealed 4-/sup 125/I-iodine estradiol in connection with one antiserum in each case of the radioligand antiserum combinations against E/sub 2/-3-CM-RSA- and E/sub 2/-6-CMO-RSA-conjugate. The double antibody method is used for separation in optimized RIA systems. The first and the second antibody reaction take place simultaneously.

  2. Influence of water quality on nitrifier regrowth in two full-scale drinking water distribution systems.

    Science.gov (United States)

    Scott, Daniel B; Van Dyke, Michele I; Anderson, William B; Huck, Peter M

    2015-12-01

    The potential for regrowth of nitrifying microorganisms was monitored in 2 full-scale chloraminated drinking water distribution systems in Ontario, Canada, over a 9-month period. Quantitative PCR was used to measure amoA genes from ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and these values were compared with water quality parameters that can influence nitrifier survival and growth, including total chlorine, ammonia, temperature, pH, and organic carbon. Although there were no severe nitrification episodes, AOB and AOA were frequently detected at low concentrations in samples collected from both distribution systems. A culture-based presence-absence test confirmed the presence of viable nitrifiers. AOB were usually present in similar or greater numbers than AOA in both systems. As well, AOB showed higher regrowth potential compared with AOA in both systems. Statistically significant correlations were measured between several water quality parameters of relevance to nitrification. Total chlorine was negatively correlated with both nitrifiers and heterotrophic plate count (HPC) bacteria, and ammonia levels were positively correlated with nitrifiers. Of particular importance was the strong correlation between HPC and AOB, which reinforced the usefulness of HPC as an operational parameter to measure general microbiological conditions in distribution systems.

  3. Radiolabelling of cholera toxin

    Energy Technology Data Exchange (ETDEWEB)

    Santos, R.G.; Neves, Nicoli M.J. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil); Abdalla, L.F.; Brandao, R.L.; Etchehebehere, L. [Ouro Preto Univ., MG (Brazil). Escola de Farmacia. Lab. de Fisiologia e Bioquimica de Microorganismos; Lima, M.E. de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas. Dept. de Bioquimica e Imunologia; Nicoli, J.R. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas. Dept. de Microbiologia

    1999-11-01

    Binding of cholera toxin to ganglioside receptors of enterocyte microvilli catalyzes the activation of adenylate cyclase causing a rise in cAMP which final result is a copious diarrhea. Saccharomyces boulardii, a nonpathogenic yeast has been used to prevent diarrhea. Although the antidiarrheic properties of S. boulardii are widely recognized, this yeast has been used on empirical basis, and the mechanism of this protective effect is unknown. The addition of cholera toxin to S. boulardii induces the raising of cAMP that triggers the activation of neutral trehalase. This suggests that toxin specifically binding to cells, is internalized and active the protein phosphorylation cascade. Our objective is labeling the cholera toxin to verify the presence of binding sites on yeast cell surfaces for the cholera toxin. Cholera toxin was radiolabelled with Na {sup 125} I by a chloramine-T method modified from Cuatrecasas and Griffiths et alii. The {sup 125} I-Cholera toxin showed a specific radioactivity at about 1000 cpm/fmol toxin. Biological activity of labeled cholera toxin measured by trehalase activation was similar to the native toxin. (author) 5 refs., 3 figs.; e-mail: nevesmj at urano.cdtn.br

  4. Occurrence of aromatic amines and N-nitrosamines in the different steps of a drinking water treatment plant.

    Science.gov (United States)

    Jurado-Sánchez, Beatriz; Ballesteros, Evaristo; Gallego, Mercedes

    2012-09-15

    The occurrence of 24 amines within a full scale drinking water treatment plant that used chlorinated agents as disinfectants was evaluated for the first time in this research. Prior to any treatment (raw water), aniline, 3-chloroaniline, 3,4-dichloroaniline and N-nitrosodimethylamine were detected at low levels (up to 18 ng/L) but their concentration increased ∼10 times after chloramination while 9 new amines were produced (4 aromatic amines and 5 N-nitrosamines). Within subsequent treatments, there were no significant changes in the amine levels, although the concentrations of 2-nitroaniline, N-nitrosodimethylamine and N-nitrosodiethylamine increased slightly within the distribution system. Eleven of the 24 amines studied were undetected either in the raw and in the treatment plant samples analysed. There is an important difference in the behaviour of the aromatic amines and N-nitrosamines with respect to water temperature and rainfall events. Amine concentrations were higher in winter due to low water temperatures, this effect being more noticeable for N-nitrosamines. Aromatic amines were detected at their highest concentrations (especially 3,4-dichloroaniline and 2-nitroaniline) in treated water after rainfall events. These results may be explained by the increase in the levels of amine precursors (pesticides and their degradation products) in raw water since the rainfall facilitated the transport of these compounds from soil which was previously contaminated as a result of intensive agricultural practices.

  5. 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

  6. Selective mono-radioiodination and characterization of a cell-penetrating peptide. L-Tyr-maurocalcine

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, Mitra; Bacot, Sandrine; Perret, Pascale; Riou, Laurent; Ghezzi, Catherine [Universite Joseph Fourier, Grenoble (France); INSERM U1039, Grenoble (France). Radiopharmaceutiques Biocliniques; Poillot, Cathy; Cestele, Sandrine [INSERM U836, Grenoble (France). Grenoble Inst. of Neuroscience; Universite Joseph Fourier, Grenoble (France); Desruet, Marie-Dominique [INSERM U1039, Grenoble (France). Radiopharmaceutiques Biocliniques; Couvet, Morgane; Bourgoin, Sandrine; Seve, Michel [CRI-INSERM U823, Grenoble (France). Inst. of Albert Bonniot; Universite Joseph Fourier, Grenoble (France); Waard, Michel de [INSERM U836, Grenoble (France). Grenoble Inst. of Neuroscience; Universite Joseph Fourier, Grenoble (France); Smartox Biotechnologies, Grenoble (France)

    2014-07-01

    Mono-and poly-iodinated peptides form frequently during radioiodination procedures. However, the formation of a single species in its mono-iodinated form is essential for quantitative studies such as determination of tissue concentration or image quantification. Therefore, the aim of the present study was to define the optimal experimental conditions in order to exclusively obtain the mono-iodinated form of L-maurocalcine (L-MCa). L-MCa is an animal venom toxin which was shown to act as a cell-penetrating peptide. In order to apply the current direct radioiodination technique using oxidative agents including chloramine T, Iodo-Gen {sup registered} or lactoperoxidase, an analogue of this peptide containing a tyrosine residue (Tyr-L-MCa) was synthesized and was shown to fold/oxidize properly. The enzymatic approach using lactoperoxidase/H{sub 2}O{sub 2} was found to be the best method for radioiodination of Tyr-L-MCa. MALDI-TOF mass spectrometry analyses were then used for identification of the chromatographic eluting components of the reaction mixtures. We observed that the production of different radioiodinated species depended upon the reaction conditions. Our results successfully described the experimental conditions of peptide radioiodination allowing the exclusive production of the mono-iodinated form with high radiochemical purity and without the need for a purification step. Mono-radioiodination of L-Tyr-MCa will be crucial for future quantitative studies, investigating the mechanism of cell penetration and in vivo biodistribution.

  7. Occurrence of disinfection byproducts in United States wastewater treatment plant effluents

    KAUST Repository

    Krasner, Stuart W.

    2009-11-01

    Effluents from wastewater treatment plants (WWTPs) contain disinfection byproducts (DBPs) of health concern when the water is utilized downstream as a potable water supply. The pattern of DBP formation was strongly affected by whether or not the WWTP achieved good nitrification. Chlorine addition to poorly nitrified effluents formed low levels of halogenated DBPs, except for (in some cases) dihalogenated acetic acids, but often substantial amounts of N-nitrosodimethyamine (NDMA). Chlorination of well-nitrified effluent typically resulted in substantial formation of halogenated DBPs but much less NDMA. For example, on a median basis after chlorine addition, the well-nitrified effluents had 57 μg/L of trihalomethanes [THMs] and 3 ng/L of NDMA, while the poorly nitrified effluents had 2 μg/L of THMs and 11 ng/L of NDMA. DBPs with amino acid precursors (haloacetonitriles, haloacetaldehydes) formed at substantial levels after chlorination of well-nitrified effluent. The formation of halogenated DBPs but not that of NDMA correlated with the formation of THMs in WWTP effluents disinfected with free chlorine. However, THM formation did not correlate with the formation of other DBPs in effluents disinfected with chloramines. Because of the relatively high levels of bromide in treated wastewater, bromine incorporation was observed in various classes of DBPs. © 2009 American Chemical Society.

  8. Hypochlorous acid-mediated oxidation of lipid components and antioxidants present in low-density lipoproteins

    DEFF Research Database (Denmark)

    Pattison, David I; Hawkins, Clare Louise; Davies, Michael Jonathan

    2003-01-01

    and antioxidants in aqueous solution (pH 7.4). The reactions of HOCl with phosphoryl-serine and phosphoryl-ethanolamine are rapid (k approximately 10(5) M(-)(1) s(-)(1)) and of comparable reactivity to many of the protein sites. The major products formed in these reactions are chloramines, which decay to give both...... and yielded k = 9 M(-)(1) s(-)(1). The reactions of the lipid-soluble antioxidants, alpha-tocopherol and ubiquinol-10, with HOCl were investigated with model compounds. For the reactions of HOCl with both Trolox and ubiquinol-0, k = 1.3 x 10(3) M(-)(1) s(-)(1); thus, these lipid soluble antioxidants...... are relatively ineffective as direct scavengers for HOCl as compared to water soluble antioxidants (e.g., ascorbate, k ca. 10(6) M(-)(1) s(-)(1)). The reaction of HOCl with hydroquinone (a simple model for ubiquinol-10) was also investigated both in aqueous solution (k = 45 M(-)(1) s(-)(1)) and in a less polar...

  9. Protein chlorination in neutrophil phagosomes and correlation with bacterial killing.

    Science.gov (United States)

    Green, Jessie N; Kettle, Anthony J; Winterbourn, Christine C

    2014-12-01

    Neutrophils ingest and kill bacteria within phagocytic vacuoles. We investigated where they produce hypochlorous acid (HOCl) following phagocytosis by measuring conversion of protein tyrosine residues to 3-chlorotyrosine. We also examined how varying chloride availability affects the relationship between HOCl formation in the phagosome and bacterial killing. Phagosomal proteins, isolated following ingestion of opsonized magnetic beads, contained 11.4 Cl-Tyr per thousand tyrosine residues. This was 12 times higher than the level in proteins from the rest of the neutrophil and ~6 times higher than previously recorded for protein from ingested bacteria. These results indicate that HOCl production is largely localized to the phagosomes and a substantial proportion reacts with phagosomal protein before reaching the microbe. This will in part detoxify the oxidant but should also form chloramines which could contribute to the killing mechanism. Neutrophils were either suspended in chloride-free gluconate buffer or pretreated with formyl-Met-Leu-Phe, a procedure that has been reported to deplete intracellular chloride. These treatments, alone or in combination, decreased both chlorination in phagosomes and killing of Staphylococcus aureus by up to 50%. There was a strong positive correlation between the two effects. Killing was predominantly oxidant and myeloperoxidase dependent (88% inhibition by diphenylene iodonium and 78% by azide). These results imply that lowering the chloride concentration limits HOCl production and oxidative killing. They support a role for HOCl generation, rather than an alternative myeloperoxidase activity, in the killing process.

  10. Flavonols modulate the effector functions of healthy individuals' immune complex-stimulated neutrophils: a therapeutic perspective for rheumatoid arthritis.

    Science.gov (United States)

    Santos, Everton O L; Kabeya, Luciana M; Figueiredo-Rinhel, Andréa S G; Marchi, Larissa F; Andrade, Micássio F; Piatesi, Fabiana; Paoliello-Paschoalato, Adriana B; Azzolini, Ana Elisa C S; Lucisano-Valim, Yara M

    2014-07-01

    Rheumatoid arthritis (RA) patients usually exhibit immune complex (IC) deposition and increased neutrophil activation in the joint. In this study, we assessed how four flavonols (galangin, kaempferol, quercetin, and myricetin) modulate the effector functions of healthy individuals' and active RA patients' IC-stimulated neutrophils. We measured superoxide anion and total reactive oxygen species production using lucigenin (CL-luc)- and luminol (CL-lum)-enhanced chemiluminescence assays, respectively. Galangin, kaempferol, and quercetin inhibited CL-lum to the same degree (mean IC50=2.5 μM). At 2.5 μM, quercetin and galangin suppressed nearly 65% CL-lum of active RA patients' neutrophils. Quercetin inhibited CL-luc the most effectively (IC50=1.71±0.36 μM). The four flavonols diminished myeloperoxidase activity, but they did not decrease NADPH oxidase activity, phagocytosis, microbial killing, or cell viability of neutrophils. The ability of the flavonols to scavenge hypochlorous acid and chloramines, but not H2O2, depended on the hydroxylation degree of the flavonol B-ring. Therefore, at physiologically relevant concentrations, the flavonols partially inhibited the oxidative metabolism of IC-stimulated neutrophils without affecting the other investigated effector functions. Using these compounds to modulate IC-mediated neutrophil activation is a promising safe therapeutic strategy to control inflammation in active RA patients.

  11. Iodine-123 labeled derivatives of methylphenidate: potential SPECT radiopharmaceuticals for brain dopamine transporters

    Energy Technology Data Exchange (ETDEWEB)

    Pan, D.; Gatley, S.J.; Chen, R.; Ding, Y.-S. [Brookhaven National Lab., Upton, NY (United States)

    1996-06-01

    Since dl-threo-[{sup 11}C]methylphenidate (Ritalin) and especially the more active enantiomer, d-threo-[{sup 11}C]methylphenidate, have favorable properties for PET studies, we prepared two radioiodinated analogs of methylphenidate, p-[{sup 123}I]iodomethylphenidate and m-[{sup 123}I]iodo-p-hydroxymethylphenidate with a view to evaluating them as potential SPECT tracers. To prepare p-[{sup 123}I]iodomethylphenidate, the p-tributyltin derivative was prepared from the previously reported p-bromomethylphenidate and reacted under acidic conditions with I-123 iodide plus chloramine-T at room temperature for 90 seconds. The predomimant radioactive product was obtained in 85% radiochemical yield and > 10 Ci/{mu}mol specific radioactivity after HPLC purification. It had the same HPLC retention time as a spectroscopically characterized non-radioactive p-iodomethylphenidate standard prepared via nitration of methylphenidate and diazotization, after protection of the secondary amino group by benzoylation. A second radioiodinated methylphenidate derivative, m-[{sup 123}I]iodop-hydroxymethylphenidate was prepared in 80% radiochemical yield by direct iodination of the known p-hydroxymethylphenidate. In this case the non-radioactive standard was prepared by iodination of p-hydroxyritalinic acid using I{sub 2} and iodic acid, followed by esterification. (author).

  12. Effects of ozone and ozone/peroxide on trace organic contaminants and NDMA in drinking water and water reuse applications.

    Science.gov (United States)

    Pisarenko, Aleksey N; Stanford, Benjamin D; Yan, Dongxu; Gerrity, Daniel; Snyder, Shane A

    2012-02-01

    An ozone and ozone/peroxide oxidation process was evaluated at pilot scale for trace organic contaminant (TOrC) mitigation and NDMA formation in both drinking water and water reuse applications. A reverse osmosis (RO) pilot was also evaluated as part of the water reuse treatment train. Ozone/peroxide showed lower electrical energy per order of removal (EEO) values for TOrCs in surface water treatment, but the addition of hydrogen peroxide increased EEO values during wastewater treatment. TOrC oxidation was correlated to changes in UV(254) absorbance and fluorescence offering a surrogate model for predicting contaminant removal. A decrease in N-nitrosodimethylamine (NDMA) formation potential (after chloramination) was observed after treatment with ozone and ozone/peroxide. However, during spiking experiments with surface water, ozone/peroxide achieved limited destruction of NDMA, while in wastewaters net direct formation of NDMA of 6-33 ng/L was observed after either ozone or ozone/peroxide treatment. Once formed during ozonation, NDMA passed through the subsequent RO membranes, which highlights the significance of the potential for direct NDMA formation during oxidation in reuse applications.

  13. Factors affecting catalysis of copper corrosion products in NDMA formation from DMA in simulated premise plumbing.

    Science.gov (United States)

    Zhang, Hong; Andrews, Susan A

    2013-11-01

    This study investigated the effects of corrosion products of copper, a metal commonly employed in household plumbing systems, on N-nitrosodimethylamine (NDMA) formation from a known NDMA precursor, dimethylamine (DMA). Copper-catalyzed NDMA formation increased with increasing copper concentrations, DMA concentrations, alkalinity and hardness, but decreased with increasing natural organic matter (NOM) concentration. pH influenced the speciation of chloramine and the interactions of copper with DMA. The transformation of monochloramine (NH2Cl) to dichloramine and complexation of copper with DMA were involved in elevating the formation of NDMA by copper at pH 7.0. The inhibiting effect of NOM on copper catalysis was attributed to the rapid consumption of NH2Cl by NOM and/or the competitive complexation of NOM with copper to limit the formation of DMA-copper complexes. Hardness ions, as represented by Ca(2+), also competed with copper for binding sites on NOM, thereby weakening the inhibitory effect of NOM on NDMA formation. Common copper corrosion products also participated in these reactions but in different ways. Aqueous copper released from malachite [Cu2CO3(OH)2] was shown to promote NDMA formation while NDMA formation decreased in the presence of CuO, most likely due to the adsorption of DMA.

  14. Manganese deposition in drinking water distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Gerke, Tammie L., E-mail: Tammie.Gerke@miamioh.edu [Department of Geology, University of Cincinnati, Cincinnati, OH 45221-0013 (United States); Little, Brenda J., E-mail: brenda.little@nrlssc.navy.mil [Naval Research Laboratory, Stennis Space Center, MS 39529 (United States); Barry Maynard, J., E-mail: maynarjb@ucmail.uc.edu [Department of Geology, University of Cincinnati, Cincinnati, OH 45221-0013 (United States)

    2016-01-15

    This study provides a physicochemical assessment of manganese deposits on brass and lead components from two fully operational drinking water distributions systems. One of the systems was maintained with chlorine; the other, with secondary chloramine disinfection. Synchrotron-based in-situ micro X-ray adsorption near edge structure was used to assess the mineralogy. In-situ micro X-ray fluorescence mapping was used to demonstrate the spatial relationships between manganese and potentially toxic adsorbed metal ions. The Mn deposits ranged in thickness from 0.01 to 400 μm. They were composed primarily of Mn oxides/oxhydroxides, birnessite (Mn{sup 3+} and Mn{sup 4+}) and hollandite (Mn{sup 2+} and Mn{sup 4+}), and a Mn silicate, braunite (Mn{sup 2+} and Mn{sup 4+}), in varying proportions. Iron, chromium, and strontium, in addition to the alloying elements lead and copper, were co-located within manganese deposits. With the exception of iron, all are related to specific health issues and are of concern to the U.S. Environmental Protection Agency (U.S. EPA). The specific properties of Mn deposits, i.e., adsorption of metals ions, oxidation of metal ions and resuspension are discussed with respect to their influence on drinking water quality. - Highlights: • Oxidation and deposition of Mn deposits in drinking water distribution pipes • In-situ synchrotron-based μ-XANES and μ-XRF mapping • Toxic metal sorption in Mn deposits.

  15. Improvement of labeling efficiency of glycoprotein-liposome conjugates with iodine-125 by using Bolton-Hunter Reagent and their distribution in mice

    Energy Technology Data Exchange (ETDEWEB)

    Kawakita, Yasunori; Kojima, Shuji [Science Univ. of Tokyo, Noda, Chiba (Japan). Research Institute for Biological Sciences; Yamazaki, Noboru

    2000-07-01

    We have developed a new type of glycoprotein-liposome conjugates and examined their potential utilities as drug-targeting carriers which exploit cellular functions of carbohydrate-binding proteins, i.e. animal lectins. An extremely low labeling efficiency, however, has been often a big problem in biodistribution study by using radiolabeled glycoprotein-liposome conjugates. In this study, improvement of the labeling efficiency was conducted by using Bolton-Hunter Reagent (BHR). First, tyrosyl groups were introduced into liposome membrane through amines of a constitutive phospholipid, dipalmitoylphosphatidlethanolamine (DPPE). Then, glycoprotein-tyrosyl group introduced liposomes were iodinated with {sup 125}I according to Chloramine-T methods. Labeling efficiency was markedly elevated in comparison with the BHR-untreated liposome conjugates. There was no significant changes in binding activity of BHR-treated glycoprotein-liposome conjugates with lectin. However, biodistribution of glycoprotein-tyrosyl group introduced liposomes in mice was significantly different from the mother conjugates. Thus, another suitable method for radioiodination of the glycoprotein-liposome conjugates should be developed. (author)

  16. Chemiluminescent method for detection of eutrophication sources by estimation of organic amino nitrogen and ammonium in water.

    Science.gov (United States)

    Meseguer-Lloret, S; Molins-Legua, C; Verdú-Andrés, J; Campíns-Falcó, P

    2006-11-01

    An automatic method has been developed for the estimation of organic amino nitrogen (CH2-NH) and ammonium in water samples. We propose a continuous flow system in which nitrogen compounds react with hypochlorite reagent to produce chloramines. Subsequently, the mixture is mixed with luminol, generating a chemiluminescence signal. The signal emission at 425 nm, registered as a function of time, decreases as nitrogen concentration increases, due to the decrease on hypochlorite concentration. A large number of nitrogen compounds have been assayed and their sensitivities compared, in milligrams per liter nitrogen. The ammonium calibration graph, expressed as N, can be used for most of the assayed compounds. The linear interval was 0.24-4 mg L(-1) N, with the detection limit 0.07 mg L(-1) N. The chemiluminescence method was applied to the analysis of several kinds of real water samples, natural, lake, irrigation ditch, fountain, residual, and seawater in order to detect possible sources of eutrophication. The accuracy (% relative error) and precision were satisfactory, with mean values of 5 +/- 4 and 3 +/- 2, respectively. This procedure has been used to estimate nitrogen content in samples before and after Kjeldahl treatment. In the same samples, the N found for the untreated samples provided a good estimation of the N Kjeldahl. Sixty samples per hour can be analyzed, and the procedure can also be used for in situ monitoring.

  17. 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.

  18. Removal of microorganisms in different stages of wastewater treatment for Mexico City.

    Science.gov (United States)

    Jiménez, B; Chávez, A; Maya, C; Jardines, L

    2001-01-01

    In this study the removal of a diversity of microorganisms during different stages of treatment was evaluated. The process scheme consisted of Advanced Primary Treatment (APT), sand filtration, and chlorine disinfection. During the first 2 stages, fecal coliforms were reduced from 1.24 x 10(9) to 1.2 x 10(8) MPN/100 mL and helminth ova were reduced to less than 1 ova/L. Nevertheless, to obtain an effluent water quality that meets the microbiological standards recommended by the World Health Organization (1989) and the Mexican norm for water destined for agricultural reuse it was necessary to disinfect the effluent with a chlorine dose of 12 mg/L for a 3 hour contact time. Under these conditions, fecal coliforms were reduced from 1.2 x 10(9) to 5.8 x 10(1) MPN/100 mL, Salmonella spp. from 5.0 x 10(8) MPN/100 mL to below the detection limit, Pseudomonas aeruginosa from 2.0 x 10(5) MPN/100 mL to below the detection limit, and protozoan cysts from 1052 to 31 cysts/L. Regrowth of bacteria was never observed during the 48 hours period following disinfection. The active chlorine was primarily in the form of chloramines thus reducing the formation of other potentially carcinogenic disinfection byproducts.

  19. Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants

    Institute of Scientific and Technical Information of China (English)

    SHAO Jiahui; FANG Xuliang; HE Yiliang; JIN Qiang

    2008-01-01

    Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditionalchlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaksin the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose.Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditionson the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration,liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9%was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically foundto be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammoniaremoval rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plantmembrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatmentplant, also paved the way towards a larger scale application.

  20. Halonitroalkanes, halonitriles, haloamides, and N-nitrosamines: a critical review of nitrogenous disinfection byproduct formation pathways.

    Science.gov (United States)

    Shah, Amisha D; Mitch, William A

    2012-01-01

    Interest in the formation of nitrogenous disinfection byproducts (N-DBPs) has increased because toxicological research has indicated that they are often more genotoxic, cytotoxic, or carcinogenic than many of the carbonaceous disinfection byproducts (C-DBPs) that have been a focus for previous research. Moreover, population growth has forced utilities to exploit source waters impaired by wastewater effluents or algal blooms. Both waters feature higher levels of organic nitrogen, that might serve as N-DBP precursors. Utilities are exploring new disinfectant combinations to reduce the formation of regulated trihalomethanes and haloacetic acids. As some of these new combinations may promote N-DBP formation, characterization of N-DBP formation pathways is needed. Formation pathways for halonitroalkanes, halonitriles, haloamides, and N-nitrosamines associated with chlorine, ozone, chlorine dioxide, UV, and chloramine disinfection are critically reviewed. Several important themes emerge from the review. First, the formation pathways of the N-DBP families are partially linked because most of the pathways involve similar amine precursors. Second, it is unlikely that a disinfection scheme that is free of byproduct formation will be discovered. Disinfectant combinations should be optimized to reduce the overall exposure to toxic byproducts. Third, the understanding of formation pathways should be employed to devise methods of applying disinfectants that minimize byproduct formation while accomplishing pathogen reduction goals. Fourth, the well-characterized nature of the monomers constituting the biopolymers that likely dominate the organic nitrogen precursor pool should be exploited to predict the formation of byproducts likely to form at high yields.

  1. [Sensitivity of surface microorganisms to disinfectants].

    Science.gov (United States)

    Krzywicka, H; Janowska, J; Tadeusiak, B

    1991-01-01

    The influence of humidity and temperature on survival of S. aureus and P. aeruginosa on the surfaces of titles, glass and blanket carriers has been estimated. The number of CFU was examined after exposure time 6 and 24 hours in temperatures of 21 degrees C, 37 degrees C and RH 35%, 95%. It was observed: 1. The important reduction of numbers of both microorganisms at temperature 37 degrees C and RH 95%, 2. The relatively high number of survival cells of P. aeruginosa on the surface of blankets at temp. 21 degrees C and RH 95%. The microorganisms on the carriers were previously kept for 24 h at temp. 21 degrees C, RH 35% and 95% and then exposed to solutions of chloramine, formalin, lysol and Sterinol (QAC). It was observed that there was a great dependence of the disinfecting effect on the degree of dessication of the surfaces. In all cases the resistance of contaminated carriers stored 24 h was higher at 95% RH than at 35% RH.

  2. Iodine-125 Chitosan-Vitamin C complex. Preparation, characterization and application

    Energy Technology Data Exchange (ETDEWEB)

    Elbarbary, Ahmed M. [National Center for Radiation Research and Technology, Cairo (Egypt). Polymer Chemistry Dept.; Shafik, H.M.; Ebeid, N.H.; Ayoub, S.M. [Atomic Energy Authority, Cairo (Egypt). Hot Lab. Center; Othman, Sameh H. [Atomic Energy Authority, Cairo (Egypt). Nuclear Research Center

    2015-07-01

    In heterogeneous conditions, water soluble Chitosan-Vitamin C Complex (CSVC) is successfully synthesized via the ionic interaction between γ-degraded CS and VC. Chitosan (CS) of low molecular weight (MW) is prepared using γ-irradiation method. The coupling of CS and vitamin C (VC) is carried out by the chemical treatment of VC with the γ-degraded CS. The formation of CSVC complex instead of physical mixture is confirmed by FT-IR and UV spectrometry. Characterization by transmission electron microscope (TEM) and dynamic light scattering (DLS) shows the formation of a nanostructure in 40 nm range. The preparation of labeled CSVC was performed using chloramines-T oxidation method. The labeling feasibility of CSVC nanostructure by Iodine-125 ({sup 125}I) is investigated. The optimized conditions of labeling are thought to be 50 μg of oxidizing agent, pH 3, and one minute reaction time. The Biodistribution activity of {sup 125}I radiolabeled CSVC nanostructure ({sup 125}I-CSVC) is examined on a group of different ascites tumor bearing mice. Calculation of the biodistribution percentages shows that the tumor, liver, and kidney are the targeting organs of {sup 125}I-CSVC nanostructure.

  3. Variation of hydroxyproline content after local injection hyaluronic acid in excessive dermal scar of rabbit ears%透明质酸注射兔耳瘢痕后羟脯氨酸含量变化

    Institute of Scientific and Technical Information of China (English)

    张阳; 柳大烈; 李希军; 李玉霞; 张选奋; 安书杰

    2002-01-01

    AIM To observe the scar formation by using hyaluronic acid (HA) and hyaluronidase (HAse) in excessive dermal scar of rabbit ears. METHODS Upon the foundation of hypertrophic scar model in rabbit ears, we tested the content of hydroxyproline (HPr) using chloramineT method by injecting HA and HAse in excessive dermal scar of rabbit ears with the establishment of saline and blank control at different time. RESULTS ① HPr contents of the HA, saline and blank groups were gradullay increased (P0.05); ③ Compared with saline group, HPr contents of the HA group were higher (P0.05);③HA组的HPr含量明显高于盐水组(P<0.05);④HAse组的HPr含量明显低于盐水组(P<0.01);⑤HA组的HPr含量明显高于HAse组(P<0.01).结论瘢痕组织中注射HA后胶原合成增加, 提示瘢痕组织中, HA含量的持续增高可导致瘢痕的异常增生.

  4. Heterotrophic bacteria in drinking water distribution system: a review.

    Science.gov (United States)

    Chowdhury, Shakhawat

    2012-10-01

    The microbiological quality of drinking water in municipal water distribution systems (WDS) depends on several factors. Free residual chlorine and/or chloramines are typically used to minimize bacterial recontamination and/or regrowth in WDS. Despite such preventive measures, regrowth of heterotrophic (HPC) and opportunistic bacteria in bulk water and biofilms has yet to be controlled completely. No approach has shown complete success in eliminating biofilms or HPC bacteria from bulk water and pipe surfaces. Biofilms can provide shelter for pathogenic bacteria and protect these bacteria from disinfectants. Some HPC bacteria may be associated with aesthetic and non-life threatening diseases. Research to date has achieved important success in understanding occurrence and regrowth of bacteria in bulk water and biofilms in WDS. To achieve comprehensive understanding and to provide efficient control against bacteria regrowth, future research on bacteria regrowth dynamics and their implications is warranted. In this study, a review was performed on the literature published in this area. The findings and limitations of these papers are summarized. Occurrences of bacteria in WDS, factors affecting bacteria regrowth in bulk water and biofilms, bacteria control strategies, sources of nutrients, human health risks from bacterial exposure, modelling of bacteria regrowth and methods of bacteria sampling and detection and quantification are investigated. Advances to date are noted, and future research needs are identified. Finally, research directions are proposed to effectively control HPC and opportunistic bacteria in bulk water and biofilms in WDS.

  5. Control technology assessment of hazardous waste disposal operations in chemicals manufacturing: walk-through survey report of E. I. Du Pont de Nemours and Company, Chambers Works, Deepwater, New Jersey

    Energy Technology Data Exchange (ETDEWEB)

    Anastas, M.

    1984-01-01

    A walk through survey was conducted to assess control technology for hazardous wastes disposal operations at du Pont de Nemours and Company (SIC-2800), Deepwater, New Jersey in November 1981. Hazardous wastes generated at the facility were disposed of by incineration, wastewater and thermal treatment, and landfilling. Engineering controls for the incineration process and at the landfill were noted. At the landfill, water from a tank trailer was sprayed periodically to suppress dust generation. Vapor control devices, such as spot scrubbers, were used during transfer of organic wastes from trailers and drums to storage prior to incineration. Wastes were also recirculated to prevent build up of grit in the strainers. The company conducted area monitoring for nitrobenzene (98953) and amines at the landfill and personal monitoring for chloramines at the incinerator. Half mask dust respirators were worn by landfill operators. Operators who unloaded and emptied drums at the incinerator were required to wear face masks, rubber gloves, and boots. The author concludes that disposal of hazardous wastes at the facility is state of the art. An in depth survey is recommended.

  6. Disinfection byproduct formation from chlorination of pure bacterial cells and pipeline biofilms.

    Science.gov (United States)

    Wang, Jun-Jian; Liu, Xin; Ng, Tsz Wai; Xiao, Jie-Wen; Chow, Alex T; Wong, Po Keung

    2013-05-15

    Disinfection byproduct (DBP) formation is commonly attributed to the reaction between natural organic matters and disinfectants, yet few have considered the contribution from disinfecting bacterial materials - the essential process of water disinfection. Here, we explored the DBP formation from chlorination and chloramination of Escherichia coli and found that most selected DBPs were detectable, including trihalomethanes, haloacetonitriles, chloral hydrate, chloropicrin, and 1,1,1-trichloro-2-propanone. A positive correlation (P = 0.08-0.09) between DBP formation and the log reduction of E. coli implied that breaking down of bacterial cells released precursors for DBP formation. As Pseudomonas aeruginosa is a dominant bacterial species in pipeline biofilms, the DBP formation potentials (DBPFPs) from its planktonic cells and biofilms were characterized. Planktonic cells formed 7-11 times greater trihalomethanes per carbon of those from biofilms but significantly lower (P disinfection of bacterial planktonic cells in source water and ex situ reaction between biofilms and residual chlorine in pipeline networks as hitherto unknown DBP sources in drinking water.

  7. [Inactivation of the chlorine-resistant bacteria isolated from the drinking water distribution system].

    Science.gov (United States)

    Chen, Yu-Qiao; Duan, Xiao-Di; Lu, Pin-Pin; Wang, Qian; Zhang, Xiao-Jian; Chen, Chao

    2012-01-01

    Inactivation experiments of seven strains of chlorine-resistant bacteria, isolated from a drinking water distribution system, were conducted with four kinds of disinfectants. All the bacteria showed high resistance to chlorine, especially for Mycobacterium mucogenicum. The CT value of 99.9% inactivation for M. mucogenicum, Sphingomonas sanguinis and Methylobacterium were 120 mg x (L x min)(-1), 7 mg x (L x min)(-1) and 4 mg x (L x min)(-1), respectively. The results of inactivation experiments showed that chlorine dioxide and potassium monopersulfate could inactive 5 lg of M. mucogenicum within 30 min, which showed significantly higher efficiency than free chlorine and monochloramine. Free chlorine was less effective because the disinfectant decayed very quickly. Chloramination needed higher concentration to meet the disinfection requirements. The verified dosage of disinfectants, which could effectively inactivate 99.9% of the highly chlorine-resistant M. mucogenicum within 1 h, were 3.0 mg/L monochloramine, 1.0 mg/L chlorine dioxide (as Cl2), and 1.0 mg/L potassium monopersulfate (as Cl2). It was suggested that the water treatment plants increase the concentration of monochloramine or apply chlorine dioxide intermittently to control the disinfectant-resistant bacteria.

  8. Evaluation of Bacteriological and Chemical Quality of Dialysis Water and Fluid in Isfahan, Central Iran

    Science.gov (United States)

    SHAHRYARI, Ali; NIKAEEN, Mahnaz; HATAMZADEH, Maryam; VAHID DASTJERDI, Marzieh; HASSANZADEH, Akbar

    2016-01-01

    Background: Chemical and microbial quality of water used in hemodialysis play key roles in a number of dialysis-related complications. In order to avoid the complications and to guarantee safety and health of patients therefore, vigorous control of water quality is essential. The objective of present study was to investigate the chemical and bacteriological characteristics of water used in dialysis centers of five hospitals in Isfahan, central Iran. Methods: A total of 30 water samples from the input of dialysis purification system and dialysis water were analyzed for chemical parameters. Heterotrophic plate count and endotoxin concentration of drinking water, dialysis water and dialysis fluid of 40 machines were also monitored over a 5-month period in 2011–2012. Results: Concentration of the determined chemicals (copper, zinc, sulfate, fluoride, chloramines and free chlorine) did not exceed the recommended concentration by the Association for the Advancement of Medical Instrumentation (AAMI) exclude lead, nitrate, aluminum and calcium. Furthermore, the magnesium; cadmium and chromium concentration exceeded the maximum level in some centers. No contamination with heterotrophic bacteria was observed in all samples, while the AMMI standard for endotoxin level in dialysis fluid (water and fluid failed to meet the all chemical and bacteriological requirements for hemodialysis. To minimize the risk of contaminants for hemodialysis patients therefore, a water quality management program including monitoring, maintenance and development of water treatment system in hemodialysis centers is extremely important. In addition, an appropriate disinfection program is needed to guarantee better control of bacterial growth and biofilm formation. PMID:27398338

  9. Manganese deposition in drinking water distribution systems.

    Science.gov (United States)

    Gerke, Tammie L; Little, Brenda J; Barry Maynard, J

    2016-01-15

    This study provides a physicochemical assessment of manganese deposits on brass and lead components from two fully operational drinking water distributions systems. One of the systems was maintained with chlorine; the other, with secondary chloramine disinfection. Synchrotron-based in-situ micro X-ray adsorption near edge structure was used to assess the mineralogy. In-situ micro X-ray fluorescence mapping was used to demonstrate the spatial relationships between manganese and potentially toxic adsorbed metal ions. The Mn deposits ranged in thickness from 0.01 to 400 μm. They were composed primarily of Mn oxides/oxhydroxides, birnessite (Mn(3+) and Mn(4+)) and hollandite (Mn(2+) and Mn(4+)), and a Mn silicate, braunite (Mn(2+) and Mn(4+)), in varying proportions. Iron, chromium, and strontium, in addition to the alloying elements lead and copper, were co-located within manganese deposits. With the exception of iron, all are related to specific health issues and are of concern to the U.S. Environmental Protection Agency (U.S. EPA). The specific properties of Mn deposits, i.e., adsorption of metals ions, oxidation of metal ions and resuspension are discussed with respect to their influence on drinking water quality.

  10. Synthesis of substituted [{sup 123}I]imidazo[1,2-a]pyridines as potential probes for the study of the peripheral benzodiazepine receptors using SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Katsifis, A.; Mattner, F.; Dikic, B.; Papazian, V. [Radiopharmaceuticals Div. R and D, ANSTO, Menai, NSW (Australia)

    2000-07-01

    The imidazo[1,2-a]pyridines N,N'-dimethyl-6-chloro-(4'-iodophenyl)imidazo[1,2-a]pyridine-3-acetamide 1. N,N'-diethyl-6-chloro-(4'-iodophenyl)imidazo[1,2-a]pyridine-3-acetamide 2, and N-methyl-6-chloro-(4'-iodophenyl)imidazo[1,2-a]pyridine-3-acetamide 3, are high affinity and selective ligands for the peripheral benzodiazepineodiazepine receptors (PBR). The [{sup 123}I]1-3 labelled analogues of these compounds were subsequently synthesised for the potential study of the PBR in vivo using SPECT. Radioiodination was achieved by iododestannylation reactions of the corresponding tributyl tin precursors with Na[{sup 123}I] in the presence of peracetic acid, chloramine-T or Iodogen. Purification of the crude product was achieved by semipreparative C-18 RP HPLC to give the products in radiochemical yields of 40-85%. The products were obtained in >97% chemical and radiochemical purity and with specific activities >80 GBq/{mu}mol. (orig.)

  11. Methods to eradicate soft tunic syndrome (STS-causing protozoa Azumiobodo hoyamushi, the highly infectious parasite from the edible ascidian (Halocynthia roretzi

    Directory of Open Access Journals (Sweden)

    Ji-Hoon Lee

    2016-03-01

    Full Text Available Abstract Although soft tunic syndrome (STS in the ascidian is a serious disease, helpful measures have yet not been established. It was examined in this study by applying aniti-parasitic drugs to eradicate the causative protozoa Azumiobodo hoyamushi from infected ascidians. Formalin was synergistic in killing parasites in vitro when co-treated with hydrogen peroxide (H2O2 or bronopol, but not with chloramine-T or povidone-iodine (PVP-I, when tested with in vitro parasite culture. The synergistic effects did not change when formalin-H2O2 (or bronopol ratios were changed. It was found that treatment periods less than 60 min achieved a sub-maximal efficacy. Increasing drug concentration while keeping 30 min period improved anti-parasitic effects. Anti-parasitic effects of formalin(F + H2O2(H were also assessed in an in vivo STS model infected with cultured parasites. It was observed that combined 50 (40F + 10H and 100 (80F +20H ppm were effective in partially preventing STS-caused mortality. In horizontally transmitted artificial STS model, significant prevention of ascidian mortality was also observed after 50 ppm. Marked reduction of living parasites were noted after drug treatments in vivo. The results provide a highly useful basis to develop a preventive or treatment measure against the currently uncontrollable STS in the ascidian.

  12. Selective chlorination of natural organic matter: identification of previously unknown disinfection byproducts.

    Science.gov (United States)

    Lavonen, Elin E; Gonsior, Michael; Tranvik, Lars J; Schmitt-Kopplin, Philippe; Köhler, Stephan J

    2013-03-01

    Natural organic matter (NOM) serve as precursors for disinfection byproducts (DBPs) in drinking water production making NOM removal essential in predisinfection treatment processes. We identified molecular formulas of chlorinated DBPs after chlorination and chloramination in four Swedish surface water treatment plants (WTPs) using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Chlorine-containing formulas were detected before and after disinfection and were therefore classified to identify DBPs. In total, 499 DBPs were detected, of which 230 have not been reported earlier. The byproducts had, as a group, significantly lower ratio of hydrogen to carbon (H/C) and significantly higher average carbon oxidation state (COS), double bond equivalents per carbon (DBE/C) and ratio of oxygen to carbon (O/C) compared to Cl-containing components present before disinfection and CHO formulas in samples taken both before and after disinfection. Electrophilic substitution, the proposed most significant reaction pathway for chlorination of NOM, results in carbon oxidation and decreased H/C while O/C and DBE/C is left unchanged. Because the identified DBPs had significantly higher DBE/C and O/C than the CHO formulas we concluded that chlorination of NOM during disinfection is selective toward components with relatively high double bond equivalency and number of oxygen atoms per carbon. Furthermore, choice of disinfectant, dose, and predisinfection treatment at the different WTPs resulted in distinct patterns in the occurrence of DBP formulas.

  13. Occurrence of regulated and emerging iodinated DBPs in the Shanghai drinking water.

    Science.gov (United States)

    Wei, Xiao; Chen, Xin; Wang, Xia; Zheng, Weiwei; Zhang, Dong; Tian, Dajun; Jiang, Songhui; Ong, Choon Nam; He, Gengsheng; Qu, Weidong

    2013-01-01

    Drinking water chlorination plays a pivotal role in preventing pathogen contamination against water-borne disease. However, chemical disinfection leads to the formation of halogenated disinfection by products (DBPs). Many DBPs are highly toxic and are of health concern. In this study, we conducted a comprehensive measurements of DBPs, including iodoacetic acid (IAA), iodoform (IF), nine haloacetic acids and four trihalomethanes in drinking waters from 13 water plants in Shanghai, China. The results suggested that IAA and IF were found in all the water treatment plants, with maximum levels of 1.66 µg/L and 1.25 µg/L for IAA and IF, respectively. Owing to deterioration of water quality, the Huangpu River has higher IAA and IF than the Yangtze River. Our results also demonstrated that low pH, high natural organic matter, ammonia nitrogen, and iodide in source waters increased IAA and IF formation. Compared to chlorine, chloramines resulted in higher concentration of iodinated DBP, but reduced the levels of trihalomethanes. This is the first study to reveal the widespread occurrence of IAA and IF in drinking water in China. The data provide a better understanding on the formation of iodinated disinfection byproducts and the findings should be useful for treatment process improvement and disinfection byproducts controls.

  14. Research Overview of Formation Mechanism for Typical Nitrogenous Disinfection Byproducts (DBPs)-Nitrosamines in Drinking Water%饮用水典型含氮消毒副产物亚硝胺类的生成机制研究综述

    Institute of Scientific and Technical Information of China (English)

    周超

    2014-01-01

    Nitrosamines are a group of emerging disinfection by-products formed during chlorine-based and chloramine-based water treatment,which have caused great attention because of their strong toxicity. The studies mainly focus on the occurrence and formation mechanism of typical nitrogenous disinfection byproducts-nitrosamines (NAms)in drinking water. In the light of some shortcomings existing,main research fields in the future and problems to be solved are proposed.%亚硝胺类是饮用水消毒处理过程中产生的一类典型含氮消毒副产物,其强烈的“三致”毒性引起人们越来越多的关注。该文从浓度分布和生成机制两个方面对亚硝胺类进行系统的分析,并针对现有亚硝胺类研究的不足之处,提出了今后研究的主要方向和需解决的问题。

  15. Free Radical Chemistry of Disinfection Byproducts. 3. Degradation Mechanisms of Chloronitromethane, Bromonitromethane and Dichloronitromethane

    Energy Technology Data Exchange (ETDEWEB)

    Bruce J. Mincher; Stephen P. Mezyk; William J. Cooper; S. Kirkham Cole; Robert V. Fox; Piero R. Gardinali

    2010-01-01

    Halonitromethanes (HNMs) are byproducts formed through ozonation and chlorine/ chloramine disinfection processes in drinking waters that contain dissolved organic matter and bromide ions. These species occur at low concentration, but have been determined to have high cytotoxicity and mutagenicity and therefore may represent a human health hazard. In this study, we have investigated the chemistry involved in the mineralization of HNMs to non-hazardous inorganic products through the application of advanced oxidation and reduction processes. We have combined measured absolute reaction rate constants for the reactions of chloronitromethane, bromonitromethane and dichloronitromethane with the hydroxyl radical and the hydrated electron with a kinetic computer model in an attempt to elucidate the reaction pathways of these HNMs. The results are compared to measurements of stable products resulting from steady-state 60Co y-irradiations of the same compounds. The model predicted the decomposition of the parent compounds and ingrowth of chloride and bromide ions with excellent accuracy, but the prediction of the total nitrate ion concentration was slightly in error, reflecting the complexity of nitrogen oxide species reactions in irradiated solution.

  16. Occurrence of regulated and emerging iodinated DBPs in the Shanghai drinking water.

    Directory of Open Access Journals (Sweden)

    Xiao Wei

    Full Text Available Drinking water chlorination plays a pivotal role in preventing pathogen contamination against water-borne disease. However, chemical disinfection leads to the formation of halogenated disinfection by products (DBPs. Many DBPs are highly toxic and are of health concern. In this study, we conducted a comprehensive measurements of DBPs, including iodoacetic acid (IAA, iodoform (IF, nine haloacetic acids and four trihalomethanes in drinking waters from 13 water plants in Shanghai, China. The results suggested that IAA and IF were found in all the water treatment plants, with maximum levels of 1.66 µg/L and 1.25 µg/L for IAA and IF, respectively. Owing to deterioration of water quality, the Huangpu River has higher IAA and IF than the Yangtze River. Our results also demonstrated that low pH, high natural organic matter, ammonia nitrogen, and iodide in source waters increased IAA and IF formation. Compared to chlorine, chloramines resulted in higher concentration of iodinated DBP, but reduced the levels of trihalomethanes. This is the first study to reveal the widespread occurrence of IAA and IF in drinking water in China. The data provide a better understanding on the formation of iodinated disinfection byproducts and the findings should be useful for treatment process improvement and disinfection byproducts controls.

  17. Immunoradiometric assay for quantification of prostate-specific antigen (PSA)

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Miriam [Institute of Nuclear Sciences and Technology, Havana (Cuba). Dept.of Radiochemistry]. E-mail: mirian@fctn.isctn.edu.cu

    2002-07-01

    To develop an immunoradiometric assay (IRMA) for quantification of total PSA in serum, we carried out the evaluation of a panel of 12 monoclonal antibodies (MAbs). The mAbs (CB-PSA 1 to CB-PSA 10) were developed in the Center of Genetic Engineering and Biotechnology (CIGB) Havana, Cuba and mAbs (CMC-H9, CMC-A5) in the Center of Immunology and Biologics (CENIB), Camaguey, Cuba. The inhibition assays were carried out using as reference a commercial equimolar assay for total PSA. For the evaluation, the mAbs were labeled with {sup 125} I by the method of Chloramine T and the capture mAbs were used conjugated with biotin. For separation, it was used the avidin coupled to magnetic particles. To validate the assay we evaluated the sensibility, inter and intraassay precision and the correlation with reference assay in 65 samples of patient under suspicion of prostate cancer. The partner CB-PSA 4 / CB-PSA 9 (capture / tracer) showed the best results in the IRMA. The developed assay presented a detection limit of 0.025 mg/L, a good intra and interassay precision and a high correlation with the reference assay. (author)

  18. Radioiodination of chicken erythrocyte histones H4 and H5 in chromatin.

    Science.gov (United States)

    Griffiths, G R; Huang, P C

    1979-08-25

    The conformational state of histones in isolated chicken erythrocyte chromatin was studied using procedures developed for probing surface proteins on membranes. Under controlled conditions, only exposed tyrosyl residues react with iodide radicals, generated either by the oxidant, chloramine-T (paratoluenesulfonyl chloramide), or the enzyme lactoperoxidase, giving monoidotyrosine. Using 125-iodine, this study compared the reactive tyrosines in free and bound histones H4, and H5. The relative extent of iodination of these histones within (H4) and outside (H5) of the nucleosomes was measured after extraction and gel electrophoresis. Each of the histones was further analyzed for the extent of specific tyrosine iodination by separating the tryptic peptides by high voltage electrophoresis. The identity of the labeled peptide was determined by dansylation of the amino acids present in each hydrolyzed peptide. The results show that there is a difference in the conformational arrangement of these histones on chromatin and in the free forms, since in chromatin not all tyrosine residues are as accessible for iodination as in the denatured state. Residue 53 of histone H5 for instance is more reactive than residues 28 and 58, indicating that the segments containing the latter residues are involved in either protein-DNA or protein-protein interactions. In histone H4, preferential labeling of 2 of the 4 tyrosines present was also observed.

  19. Plasma half-life and organ uptake ratio of radiolabeled glandular kallikrein in control and nephrectomized rats

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, K.; Iwata, T.; Kokubu, T.

    1986-01-01

    The purified rat urinary kallikrein was radiolabeled by lactoperoxidase method and by chloramine T method. Plasma half-life of radiolabeled kallikrein was 5.06 +/- 0.59 (n = 5) min in control rats and 5.24 +/- 0.42 (n = 5) min in nephrectomized rats. There was no difference between two groups. From autoradiogram, main metabolic organs of radiolabeled kallikrein were liver, kidney and spleen. Total uptake of radiolabeled kallikrein in ech organ was the highest in liver (73.2%). The uptake per g tissue of radiolabeled kallikrein in each organ was high in liver (33.0%), kidney (31.4%) and spleen (21.1%). These results suggest that the active kallikrein is metabolized mainly in the liver, and kidney is not so an important organ to metabolize or to eliminate the active kallikrein in plasma. In order to clarify the mode of existence of active kallikrein in plasma, the following experiment was done by using disc gel electrophoresis. Radioactive profile of radiolabeled kallikrein showed one peak (Rf = 1.0), but radiolabeled kallikrein mixed with rat plasma showed two peaks, that is small peak (Rf = 1.0), and main peak (RF = 0.5). The most of radiolabeled kallikrein was bound to plasma protein and only five per cent was in free form. Furthermore, the binding of radiolabeled kallikrein to plasma protein was interfered by the addition of active kallikrein. These results suggest the possibility of existence of kallikrein binding protein in plasma.

  20. Oxidative radioiodination damage to human lactoferrin

    Energy Technology Data Exchange (ETDEWEB)

    Rosenmund, A.; Kuyas, C.; Haeberli, A.

    1986-11-15

    Oxidative iodination of human lactoferrin (Lf) commonly performed by using the chloramine-T, the Iodogen or the lactoperoxidase method produces an unreliable tracer protein because of excessive and heterogeneous polymer formation. Before iodination a minor tetramer fraction may be demonstrable in iron-saturated Lf only. /sup 125/I-Lf polymers are mainly covalently linked, as suggested by the lack of substantial dissociation in SDS/polyacrylamide-gel electrophoresis. Damage to the /sup 125/I-Lf monomer may be another consequence of oxidative iodination. This is demonstrated in SDS/polyacrylamide-gel electrophoresis where 50% of the radioactivity of apparently normal monomer (Msub(r) 75000) is displaced to a lower-Msub(r) region (30000-67000) after reduction with dithiothreitol. Non-oxidative iodination by the Bolton-Hunter technique produces an antigenetically stable tracer that is not being subjected to polymerization and monomer degradation as judged by high performance gel chromatography and SDS/polyacrylamide-gel electrophoresis with and without dithiothreitol treatment. It is concluded that oxidation in itself leads to covalent non-disulphide cross-linking between human Lf molecules and, possibly, to intramolecular peptide-bond breaking becoming unmasked under reducing conditions.

  1. Preparation and properties of /sup 3/H-phe/sup B1/ insulin

    Energy Technology Data Exchange (ETDEWEB)

    Grant, K.I.

    1986-01-01

    Insulin iodinated by both the lactoperoxidase and chloramine-T methods was found in accordance with many published reports to bind to plasma membrane. It was found, however not to obey isotope dilution laws in its displacement from plasma membrane by natural insulin. It was shown to be heterogeneous on reverse-phase HPLC, to contain diiodotyrosine and to have a reduced biological activity in an in vivo assay. Thus an insulin labelled semi-synthetically with /sup 3/H-phenylalaine at position B1 was prepared. A method already published was attempted, but without success. A different scheme of synthesis was developed using 2-t-butoxycarbonyloxyimino-2-phenylacetonitrile as the t-butoxycarbonylating agent and HPLC as the mode of separation of insulin derivatives. Using L-(2,3,4,5,6-/sup 3/H) phenylalaine a labelled insulin of specific radioactivity of 60 Ci/mmole was made. Characterization by the techniques of HPLC, acid-urea polyacrylamide gel electrophoresis, dansylation, Edman degradation and gel exclusion chromatography showed the labelled insulin to be indistinguishable from the natural hormone, and to contain a single covalently bound /sup 3/H-phe residue.

  2. Development of an 'In vitro' system for the caption essay of T3; Desarrollo de un sistema 'In vitro' para el ensayo de captacion de T3

    Energy Technology Data Exchange (ETDEWEB)

    Lavalley, C.; Ferro, G.; Zambrano, F.; Lezama, J

    1990-02-15

    Triiodothyronine uptake (T3U) is a qualitative technique for evaluation of the unsaturation capacity of thyroid binding globulin (TBG). This paper presents results related to a T3 standardized serum and the integration of T3-I-125, and adsorbent for labelled hormone. Labelled hormone were prepared by the chloramine T method and then purified by high performance liquid chromatography. The specific activity was 500 {mu} Ci/ {mu} g. Various adsorbents such as: Norit A Charcoal, calcium silicate, talc, bovine serum albumin macroaggregated (BSAM) were used in different buffers as: Tris-HCl, barbital and Michaelis. Standardized serum was prepared by mixing different euthyroid sera. Best conditions for T3U assays were achieved with 15 mg/ml. BSAM at pH 8.6 in presence of Tris-HCl buffer for hypothyroid and hyperthyroid sera, for which we obtained < 0.9 {+-} 0.04 and > 1.1 {+-} 0.05 respectively as a T3U index with a 3.0 % of coefficient variation. The reagents so prepared can be conveniently used for T3U assays. (Author)

  3. Antiseptics and microcosm biofilm formation on titanium surfaces

    Directory of Open Access Journals (Sweden)

    Georgia VERARDI

    2016-01-01

    Full Text Available Abstract Oral rehabilitation with osseointegrated implants is a way to restore esthetics and masticatory function in edentulous patients, but bacterial colonization around the implants may lead to mucositis or peri-implantitis and consequent implant loss. Peri-implantitis is the main complication of oral rehabilitation with dental implants and, therefore, it is necessary to take into account the potential effects of antiseptics such as chlorhexidine (CHX, chloramine T (CHT, triclosan (TRI, and essential oils (EO on bacterial adhesion and on biofilm formation. To assess the action of these substances, we used the microcosm technique, in which the oral environment and periodontal conditions are simulated in vitro on titanium discs with different surface treatments (smooth surface - SS, acid-etched smooth surface - AESS, sand-blasted surface - SBS, and sand-blasted and acid-etched surface - SBAES. Roughness measurements yielded the following results: SS: 0.47 µm, AESS: 0.43 µm, SB: 0.79 µm, and SBAES: 0.72 µm. There was statistical difference only between SBS and AESS. There was no statistical difference among antiseptic treatments. However, EO and CHT showed lower bacterial counts compared with the saline solution treatment (control group. Thus, the current gold standard (CHX did not outperform CHT and EO, which were efficient in reducing the biofilm biomass compared with saline solution.

  4. Novel pyrazole integrated 1,3,4-oxadiazoles: synthesis, characterization and antimicrobial evaluation.

    Science.gov (United States)

    Ningaiah, Srikantamurthy; Bhadraiah, Umesha K; Doddaramappa, Shridevi D; Keshavamurthy, Shubakara; Javarasetty, Chethan

    2014-01-01

    A novel series of 2-(5-methyl-1,3-diphenyl-1H-pyrazol-4-yl)-5-phenyl-1,3,4-oxadiazoles 7(a-m) were synthesized either by cyclization of N'-benzoyl-5-methyl-1,3-diphenyl-1H-pyrazole-4-carbohydrazide 4a using POCl3 at 120°C or by oxidative cyclization of hydrazones derived from various arylaldehyde and (E)-N'-benzylidene-5-methyl-1,3-diphenyl-1H-pyrazole-4-carbohydrazide 5(a-d) using chloramine-T as oxidant. Newly synthesized compounds were characterized by analytical and spectral (IR, (1)H NMR, (13)C NMR and LC-MS) methods. The synthesized compounds were evaluated for their antimicrobial activity and were compared with standard drugs. The compounds demonstrated potent to weak antimicrobial activity. Among the synthesized compounds, compound 7m emerged as an effective antimicrobial agent, while compounds 7d, 7f, 7i and 7l showed good to moderate activity. The minimum inhibitory concentration of the compounds was in the range of 20-50μgmL(-1) against bacteria and 25-55μgmL(-1) against fungi. The title compounds represent a novel class of potent antimicrobial agents.

  5. The study of labeling with Iodine-131 of monoclonal antibody anti-CD20 used for the treatment of non-Hodgkin lymphoma; Estudo de marcacao com Iodo-131 de anticorpo monoclonal anti-CD20 na terapia de linfoma nao-Hodgkin

    Energy Technology Data Exchange (ETDEWEB)

    Akanji, Akinkunmi Ganiyu

    2006-07-01

    Lymphomas are malignancies of the lymphatic system, described by Thomas Hodgkin in 1932. Traditionally, lymphomas are classified in two basic groups: Hodgkin disease and non-Hodgkin lymphoma (NHL). Patients with NHL were earlier treated with radiotherapy alone or in combination with immunotherapy using monoclonal antibody anti-CD20 (ex., Rituximab-Mabthera, Roche). However, Radioimmunotherapy is a new modality of treatment for patients with NHL, in which cytotoxic radiation from therapeutic radioisotopes is delivered to tumors through monoclonal antibodies. This study focused on labeling conditions of monoclonal antibody anti-CD20 (Rituximab-Mabthera, Roche) with iodine-131, by direct radioiodination method using Chloramine-T as oxidizing agent. Labeling parameters investigated were: Radiochemical purity (RP), method of purification, incubation time, antibody mass, oxidative agent mass, stability in vitro, stability in vivo, immunoreactivity and biological distribution performed in normal Swiss mouse. Product of high radiochemical purity was obtained with no notable difference between the methods applied. No clear evidence of direct influence of incubation time on radiochemical purity of the labeled antibody was observed. Whereas, a clear evidence of direct influence of activity on radiochemical purity of the labeled antibody was observed when antibody mass was varied. After purification, the labeled product presented radiochemical purity of approximately 100 %. Product of superior radiochemical yield was observed when standard condition of labeling was used. The labeled product presented variation in radiochemical purity using five different stabilizer conditions. The condition in which gentisic acid was combined with freeze appears more suitable and capable of minimizing autoradiolysis of the antibody labeled with high therapeutic activity of iodine-131. The labeled product presented low immunoreactivity when compared to the literature. Biological distribution in

  6. Nano-silver in drinking water and drinking water sources: stability and influences on disinfection by-product formation.

    Science.gov (United States)

    Tugulea, A-M; Bérubé, D; Giddings, M; Lemieux, F; Hnatiw, J; Priem, J; Avramescu, M-L

    2014-10-01

    Nano-silver is increasingly used in consumer products from washing machines and refrigerators to devices marketed for the disinfection of drinking water or recreational water. The nano-silver in these products may be released, ending up in surface water bodies which may be used as drinking water sources. Little information is available about the stability of the nano-silver in sources of drinking water, its fate during drinking water disinfection processes, and its interaction with disinfection agents and disinfection by-products (DBPs). This study aims to investigate the stability of nano-silver in drinking water sources and in the finished drinking water when chlorine and chloramines are used for disinfection and to observe changes in the composition of DBPs formed when nano-silver is present in the source water. A dispersion of nano-silver particles (10 nm; PVP-coated) was used to spike untreated Ottawa River water, treated Ottawa River water, organic-free water, and a groundwater at concentrations of 5 mg/L. The diluted dispersions were kept under stirred and non-stirred conditions for up to 9 months and analyzed weekly using UV absorption to assess the stability of the nano-silver particles. In a separate experiment, Ottawa River water containing nano-silver particles (at 0.1 and 1 mg/L concentration, respectively) was disinfected by adding sodium hypochlorite (a chlorinating agent) in sufficient amounts to maintain a free chlorine residual of approximately 0.4 mg/L after 24 h. The disinfected drinking water was then quenched with ascorbic acid and analyzed for 34 neutral DBPs (trihalomethanes, haloacetonitriles, haloacetaldehydes, 1,1 dichloro-2-propanone, 1,1,1 trichloro-2-propanone, chloropicrin, and cyanogen chloride). The results were compared to the profile of DBPs obtained under the same conditions in the absence of nano-silver and in the presence of an equivalent concentration of Ag(+) ions (as AgNO3). The stability of the nano-silver dispersions in

  7. 在饮水中典型溶解性有机氮酪氨酸氯化生成氯仿的机理分析%The Mechanism Analysis of Formation of Chloroform during Typical Dissolved Organic Nitrogen Tyrosine Chlorination in Drinking Water

    Institute of Scientific and Technical Information of China (English)

    楚文海; 高乃云; 赵世嘏; 邓慧萍

    2009-01-01

    Chlorination disinfection of drinking water effectively prevents waterborne diseases, but results in unintended disinfection byproducts (DBPs) from the reactions between organic materials in water and disinfectants. As alanine (Ala), phenylalanine (Phe) and tyrosine (Tyr) exist in much source water, the chlorination characteristic of the three amino acids (AA) and the formation pathways for chloroform (CF) during chlorination of model Tyr were studied. Chlorine demand and CF yield of the important intermediate product 2,4,6-trichlorophenol (2,4,6-TCP) were also examined. The results indicated that chlorine demand and CF yield of Tyr were much higher than those of Ala and Phe based on the same chlorination conditions, which indicated that Tyr was an important precursor of CF. Based on the analysis of GC/MS and calculation of frontier electron densities (FED~2), the formation pathway of CF during chlorination of Tyr was proposed as Tyr→4-monochlorophenol (4-MCP) → 2,4-dichlorophenol (2,4-DCP) →2,4,6-TCP →CF. The yields of CF and 2,4,6-TCP could be reduced by switching chlorination to chloramination. However, the disinfec-tion performance of chloramination is inferior to chlorination. The removal of precursor (Tyr, etc.) before disinfection may be a more promising method to reduce the generation of CF.%饮用水氯化消毒可以有效杀灭细菌,但同时会产生危害人体健康的消毒副产物(DBP).DBP生成机理研究是有效控制DBP的前提.溶解性有机氮(DON)是DBP的重要前体物,选取典型DON-丙氨酸(Ala)、苯丙氨酸(Phe)和酪氨酸(Tyr作为氯仿(CF)等DBP的前体物,研究三种氨皋酸(AA)的耗氯量和CF产率;同时考察了Tyr氯化中间产物2,4,6-TCP的氯化特性和CF产率;采用GC/MS扫描和前线轨道理论验证,探讨了CF的主要生成路径.研究发现,在同等氯化反应条件下,由于侧链基团的不同,Tyr的耗氯量以及CF产率都明显高于Ala和Phe,从而说明Tyr确实是一种重要

  8. Synthesis,Crystal Structure and Biological Activity of 2-(Anthracen-9-yl)-5-p-tolyl-1,3,4-oxadiazole

    Institute of Scientific and Technical Information of China (English)

    LI Xin-Wei; HE Dao-Hang

    2012-01-01

    A novel compound,2-(anthracen-9-yl)-5-p-tolyl-1,3,4-oxadiazole(C23H16N2O),has been synthesized by the condensation of 4-methylbenzohydrazide and anthracene-9-carbaldehyde in an ethanol solution with chloramine-T.The compound was characterized by 1H-NMR,13C-NMR,MS and single-crystal X-ray diffraction.The crystal belongs to the triclinic system,space group P with a = 7.7817(4),b = 8.8544(5),c = 12.4726(8) ,β = 92.8520(10)°,Z = 2,V = 826.58(8) 3,Dc = 1.352 g/cm3,Mr = 336.38,λ(MoKα) = 0.71073 ,μ = 0.084 mm-1,F(000) = 352,R = 0.0381 and wR = 0.1099.The dihedral angle between anthracene skeleton and phenyl ring is 64.19°.A total of 6354 unique reflections were collected,of which 3172 with I 〉 2σ(I) were observed.X-ray analysis indicated an offset face-to-face π-π stacking interaction between anthracene skeletons and an offset face-to-face π-π stacking interaction between phenyl ring planes.The novel compound molecules are connected through the offset face-to-face π-π stacking interactions to generate a three-dimensional network.The preliminary bioassay results showed that the novel compound exhibited significant insect growth inhibitory activity against Spodoptera litura Fabricius larvae.

  9. Mechanistic Investigations of Oxidation of Some Dipeptides by Sodium N-chloro-p-toluenesulfonamide in Alkaline Medium: A Kinetic Study

    Institute of Scientific and Technical Information of China (English)

    PUTTASWAMY; VAZ Nirmala; RAJENAHALLY VGOWDA Jagadeesh

    2008-01-01

    The kinetics of oxidation of five dipeptides (DPP) viz., glycylglycine (Gly-Gly), L-alanyl-L-alanine (Ala-Ala),L-valyl-L-valine (Val-Val), L-leucyl-L-leucine (Leu-Leu) and phenylglycyl-phenylglycine (Phg-Phg) by sodium N-chloro-p-toluenesuifonamide or chloramine-T (CAT) in NaOH medium was studied at 308 K. The reactions follow identical kinetics for all the dipeptides, being first-order dependence each on [CAT]o, [DPP]o and fractional-order on [OH-]. Addition of p-toluenesulfonamide or halide ions (CI- or Br-) has no significant effect on the rate of reaction. The reaction rate was found to increase with increase in ionic strength of the medium. The solvent isotope effect was studied using D2O. The activation parameters for the reaction were computed from Arrhenius plots. Equilibrium and decomposition constants were evaluated. The oxidation products of the dipeptides were identiffed as their corresponding aldehydes. An isokinetic relationship was observed with β=352 K, indicating that enthalpy factors control the reaction rate. CH3C6H4SO2NCl- of the oxidant has been postulated as the reactive oxidizing species. Under comparable experimental conditions, the rate of oxidation of the dipeptides increases in the order: Phg-Phg>Ala-Ala>Val-Val>Leu-Leu>Gly-Gly. The kinetics of oxidation of the dipeptides have also been compared with those of their corresponding monomer amino acids. The observed results have been explained by a plausible mechanism and the related rate law has been deduced.

  10. Iodine-123 salmon calcitonin, an imaging agent for calcitonin receptors: synthesis, biodistribution, metabolism and dosimetry in humans

    Energy Technology Data Exchange (ETDEWEB)

    Blower, P.J.; Kettle, A.G.; Leak, A.; O`Doherty, M.J. [Department of Nuclear Medicine, Kent and Canterbury Hospital, Canterbury (United Kingdom); Puncher, M.R.B.; George, S.; Dorsch, S.; Naylor, L.H. [Department of Biosciences, University of Kent, Canterbury (United Kingdom)

    1998-02-01

    A modified chloramine-T method was used to label a pharmaceutical form of salmon calcitonin (SCT) with iodine-123. Labelling can be performed within 5 min including purification, resulting in >95% radiochemical purity and 70% yield. Digestion analysis shows labelling with two iodine atoms on the tyrosine residue. A Chinese hamster ovary cell-based assay showed that the receptor binding and activation were not impaired by the labelling. Biodistribution in mice was similar to that of commercially available mono-iodinated {sup 125}I-labelled SCT, kidney being the principal target organ. Evaluation in three patients previously diagnosed as having Paget`s disease (injected with 37 MBq [{sup 123}I]diiodotyrosyl{sup 22}-SCT, containing less than 4 IU hormone, imaged dynamically up to 0.5 h and at intervals up to 24 h) shows early uptake in liver, kidney and sites of known Paget`s disease but not in normal bone, and later uptake in thyroid and stomach. Blood clearance was fitted to a biexponential with half-lives of 3.4-7.4 min and 3-34 h. Radiation dosimetry was estimated using MIRDOSE 3. The highest doses (mean mGy/MBq) were to thyroid (6.8 x 10{sup -1}) and kidney (6.0 x 10{sup -2}), with a whole-body dose 3.0 x 10{sup -2}. High performance liquid chromatography analysis revealed that urinary radioactivity was mostly in the form of iodide and diiodotyrosine within minutes of injection, indicating rapid in vivo breakdown.(orig. /MG) (orig.) With 8 figs., 1 tab., 28 refs.

  11. Synthesis of 125I Labeled Estradiol-17-Hemisuccinate and Its Binding Study to Estrogen Receptors Using Scintillation Proximity Assay Method

    Directory of Open Access Journals (Sweden)

    Y. Susilo

    2012-12-01

    Full Text Available Research was carried out to obtain a selective ligand which strongly bind to estrogen receptors through determination of binding affinity of estradiol-17β-hemisuccinate. Selectivity of these compounds for estrogen receptor was studied using Scintillation Proximity Assay (SPA method. Primary reagents required in the SPA method including radioligand and receptor, the former was obtained by labeling of estradiol-17β-hemisuccinate with 125I, while MCF7 was used as the receptor. The labeling process was performed by indirect method via two-stage reaction. In this procedure, first step was activation of estradiol-17β-hemisuccinate using isobutylchloroformate and tributylamine as a catalist, while labeling of histamine with 125I was carried out using chloramin-T method to produce 125I-histamine. The second stage was conjugation of activated estradiol-17β-hemisuccinate with 125I-histamine. The product of estradiol-17β-hemisuccinate labeled 125I was extracted using toluene. Furtherly, the organic layer was purified by TLC system. Characterization of estradiol-17β-hemisuccinate labeled 125I from this solvent extraction was carried out by determining its radiochemical purity and the result was obtained using paper electrophoresis and TLC were 79.8% and 84.4% respectively. Radiochemical purity could be increased when purification step was repeated using TLC system, the result showed up to 97.8%. Determination of binding affinity by the SPA method was carried out using MCF7 cell lines which express estrogen receptors showed the value of Kd at 7.192 x 10-3 nM and maximum binding at 336.1 nM. This low value of Kd indicated that binding affinity of estradiol-17β-hemisuccinate was high or strongly binds to estrogen recepto

  12. Kinetics of Chlorination of Benzophenone-3 in the Presence of Bromide and Ammonia.

    Science.gov (United States)

    Abdallah, Pamela; Deborde, Marie; Dossier Berne, Florence; Karpel Vel Leitner, Nathalie

    2015-12-15

    The aim of this study was to assess the impact of chlorination on the degradation of one of the most commonly used UV filters (benzophenone-3 (BP-3)) and the effects of bromide and ammonia on the kinetics of BP-3 elimination. Bromide and ammonia are rapidly converted to bromine and chloramines during chlorination. At first, the rate constants of chlorine, bromine and monochloramine with BP-3 were determined at various pH levels. BP-3 was found to react rapidly with chlorine and bromine, with values of apparent second order rate constants equal to 1.25(±0.14) × 10(3) M(-1)·s(-1) and 4.04(±0.54) × 10(6) M(-1)·s(-1) at pH 8.5 for kChlorine/BP-3 and kBromine/BP-3, respectively, whereas low monochloramine reactivity was observed (kNH2Cl/BP-3 = 0.112 M(-1)·s(-1)). To assess the impact of the inorganic content of water on BP-3 degradation, chlorination experiments with different added concentrations of bromide and/or ammonia were conducted. Under these conditions, BP-3 degradation was found to be enhanced in the presence of bromide due to the formation of bromine, whereas it was inhibited in the presence of ammonia. However, the results obtained were pH dependent. Finally, a kinetic model considering 18 reactions was developed using Copasi to estimate BP-3 degradation during chlorination in the presence of bromide and ammonia.

  13. 原料奶粉及乳饮料中L-羟脯氨酸的含量测定%Determination of L-hydroxyproline in raw milk powder and milk drink

    Institute of Scientific and Technical Information of China (English)

    陈铭中; 钟旭美; 胡洪森

    2011-01-01

    The method of P-dimethylaminobenzaldehyde spectrophotom etry was used to determine L-hydroxyproline in raw milk powder and milk drink.The result was stable and the recovery rate was high.After hydrolyzed with acid,L-hydroxyproline was released and oxidized by chloramine T.L-hydroxyproline oxide reacted with P-dimethylaminobenzaldehyde and formed red compounds,the absorbance was detected at 580 nm.The method was simple and accurate.Compared with other detecting methods,the expense of it was smaller.It could provide reference for enterprises to detect whether product was adulterated hydrolyzed protein in raw milk powder and milk drink.%采用对二甲氨基苯甲醛分光光度法测定奶粉及乳饮料中L-羟脯氨酸,具有较好的稳定性。奶粉及乳饮料经浓盐酸水解,得到的L-羟脯氨酸经过氯胺T氧化,与对二甲氨基苯甲醛反应生成红色物质,在558nm下测定吸光值。该方法操作简单、准确率高、检测费用相对少,可用于企业奶粉原料掺水解蛋白及产品中是否掺有水解蛋白的检测提供依据。

  14. Seasonal evaluation of the presence of 46 disinfection by-products throughout a drinking water treatment plant.

    Science.gov (United States)

    Serrano, Maria; Montesinos, Isabel; Cardador, M J; Silva, Manuel; Gallego, Mercedes

    2015-06-01

    In this work, we studied a total of 46 regulated and non-regulated disinfection by-products (DBPs) including 10 trihalomethanes (THMs), 13 haloacetic acids (HAAs), 6 halonitromethanes (HNMs), 6 haloacetonitriles (HANs) and 11 aldehydes at different points in a drinking water treatment plant (DWTP) and its distribution network. Determining an increased number of compounds and using accurate, sensitive analytical methodologies for new DBPs can be useful to overcome some challenges encountered in the comprehensive assessment of the quality and safety of drinking water. This paper provides a detailed picture of the spatial and seasonal variability of DBP concentrations from raw water to distribution network. Samples were collected on a monthly basis at seven different points in the four seasons of a year to acquire robust data for DBPs and supplementary quality-related water parameters. Only 5 aldehydes and 2 HAAs were found in raw water. Chlorine dioxide caused the formation of 3 new aldehydes (benzaldehyde included), 5 HAAs and chloroform. The concentrations of DBPs present in raw water were up to 6 times higher in the warmer seasons (spring and summer). The sedimentation process further increased their concentrations and caused the formation of three new ones. Sand filtration substantially removed aldehydes and HAAs (15-50%), but increased the levels of THMs, HNMs and HANs by up to 70%. Chloramination raised the levels of 8 aldehydes and 7 HAAs; also, it caused the formation of monoiodoacetic acid, dibromochloromethane, dichloroiodomethane and bromochloroacetonitrile. Therefore, this treatment increases the levels of existing DBPs and leads to the formation of new ones to a greater extent than does chlorine dioxide. Except for 5 aldehydes, the 23 DBPs encountered at the DWTP exit were found at increased concentrations in the warmer seasons (HAAs by about 50% and THMs by 350%).

  15. Intracellular Ca(2+) and Zn(2+) signals during monochloramine-induced oxidative stress in isolated rat colon crypts.

    Science.gov (United States)

    Cima, Robert R; Dubach, J Matthew; Wieland, Aaron M; Walsh, Breda M; Soybel, David I

    2006-02-01

    During acute exacerbations of inflammatory bowel diseases, oxidants are generated through the interactions of bacteria in the lumen, activated granulocytes, and cells of the colon mucosa. In this study we explored the ability of one such class of oxidants, represented by monochloramine (NH(2)Cl), to serve as agonists of Ca(2+) and Zn(2+) accumulation within the colonocyte. Individual colon crypts prepared from Sprague-Dawley rats were mounted in perfusion chambers after loading with fluorescent reporters fura 2-AM and fluozin 3-AM. These reporters were characterized, in situ, for responsiveness to Ca(2+) and Zn(2+) in the cytoplasm. Responses to different concentrations of NH(2)Cl (50, 100, and 200 microM) were monitored. Subsequent studies were designed to identify the sources and mechanisms of NH(2)Cl-induced increases in Ca(2+) and Zn(2+) in the cytoplasm. Exposure to NH(2)Cl led to dose-dependent increases in intracellular Ca(2+) concentration ([Ca(2+)](i)) in the range of 200-400 nM above baseline levels. Further studies indicated that NH(2)Cl-induced accumulation of Ca(2+) in the cytoplasm is the result of release from intracellular stores and basolateral entry of extracellular Ca(2+) through store-operated channels. In addition, exposure to NH(2)Cl resulted in dose-dependent and sustained increases in intracellular Zn(2+) concentration ([Zn(2+)](i)) in the nanomolar range. These alterations were neutralized by dithiothreitol, which shields intracellular thiol groups from oxidation. We conclude that Ca(2+)- and Zn(2+)-handling proteins are susceptible to oxidation by chloramines, leading to sustained, but not necessarily toxic, increases in [Ca(2+)](i) and [Zn(2+)](i). Under certain conditions, NH(2)Cl may act not as a toxin but as an agent that activates intracellular signaling pathways.

  16. Comparative studies of endotoxin uptake by isolated rat Kupffer and peritoneal cells.

    Science.gov (United States)

    Fox, E S; Thomas, P; Broitman, S A

    1987-12-01

    The process of uptake of endotoxin by cells of the reticuloendothelial system is of current interest. Rabbit peritoneal macrophages have been used to study macrophage-endotoxin interactions and have suggested a receptor-mediated process. It is generally believed that the site of in vivo endotoxin clearance is the liver and that this clearance involves the Kupffer cell population. In the current report, the uptake characteristics of iodine-125-labeled Salmonella minnesota lipopolysaccharide (LPS) were compared in both isolated rat Kupffer cells and elicited rat peritoneal cells. Both types of cells were isolated from male Sprague-Dawley rats fed a semisynthetic AIN-76 5% saturated-fat diet either by peritoneal lavage for peritoneal cells or by collagenase perfusion followed by purification on a 17.5% metrizamide gradient for Kupffer cells. Hot phenol water-extracted S. minnesota LPS was labeled with iodine by the chloramine-T method following a reaction with methyl-p-hydroxybenzimidate. The in vitro uptake of [125I]LPS by Kupffer cells was unsaturable up to concentrations of 33.33 micrograms/ml, while peritoneal cells became saturated at between 16.67 and 25 micrograms of LPS per ml. Uptake by both types of cells could be inhibited by a 10-fold excess of unlabeled LPS. Kinetic experiments demonstrated that Kupffer cells were unsaturable after 60 min of incubation, while peritoneal cells were saturable after 40 min of incubation. Pretreatment with 75 mM colchicine inhibited uptake by peritoneal cells but not Kupffer cells, while pretreatment with 12 mM 2-deoxyglucose inhibited uptake by Kupffer cells but not peritoneal cells. These results are consistent with a process of receptor-mediated endocytosis for peritoneal cells, while Kupffer cells may internalize endotoxins by absorptive pinocytosis. These results suggest that studies of peritoneal cell-endotoxin interactions do not accurately describe the physiologic process within the liver, the major site for the

  17. Identification of the binding subunit of the D/sub 1/-dopamine receptor by photoaffinity crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Amlaiky, N.; Berger, J.G.; Chang, W.; McQuade, R.D.; Caron, M.G.

    1986-03-01

    A derivative of the potent D/sub 1/ antagonist SCH-23390 has been synthesized. This compound, (R,S)-1-(m-aminophenyl)-7-chloro-8-hydroxy-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SCH-38548), has been radioiodinated by a chloramine T procedure yielding 3 radioiodinated products. One of these separated isomers (R/sub f/ = 0.35; CH/sub 2/Cl/sub 2/:MEOH:TEA; 82.5:17.5:0.1 on TLC) binds reversibly to rat striatal membranes with high affinity (K/sub D/ approx. 80 pM) appropriate stereoselectivity and D/sub 1/-dopaminergic specificity. (/sup 125/I)SCH-38548 can be covalently incorporated into a peptide of M/sub r/ approx. 72,000 using the heterobifunctional crosslinking reagent N-succinimidyl-6-(4'-azido-2'-nitro-phenylamino) hexanoate. Covalent incorporation of (/sup 125/I) SCH-38548 into the M/sub r/ approx. 72,000 peptide can be blocked by dopaminergic agents with D/sub 1/-dopaminergic specificity (for agonists: SKF 38393 > apomorphine > dopamine; for antagonists: SCH-23390 > cis-flupentixol >>> trans-flupentixol). The D/sub 1/-dopaminergic selectivity and specificity of the labeling was further demonstrated by the fact that other antagonists such as domperidone, ketanserin, phentolamine and alprenolol did not compete for the covalent labeling of the M/sub r/ approx. 72,000 peptide. This new radioligand should be useful in the molecular characterization of the D/sub 1/-dopaminergic receptor from various sources.

  18. Excretory-secretory and somatic antigens in the diagnosis of human filariasis.

    Science.gov (United States)

    Kaushal, N A; Hussain, R; Ottesen, E A

    1984-06-01

    In order to compare the immunodiagnostic value of excretory-secretory (E-S) antigens derived from adult Brugia malayi worms with somatic antigens derived from adults, microfilariae (Mf) and infective larvae (L3) of these parasites, well defined serum pools from patients with filarial (brugia, bancrofti, loa and perstans) and non-filarial (ascaris, stronglyoides, toxocara, echinococcus, cysticercus and schistosoma) helminth infections were tested against antigens derived from these different life cycle stages of B. malayi in a Staphylococcus aureus radioimmunoprecipitation assay (S. aureus RIA). The adult brugia antigens proved significantly more discriminatory than those of the other parasite stages, with the homologous brugia serum pool also showing greater reactivity to adult than to L3 and Mf antigens. Similar results were obtained when individual sera from patients (rather than serum pools) were tested in the same assay. The most surprising finding was the minimal reactivity seen between the adult filarial antigens and the non-filarial serum pools despite the presence in these pools of strong antibody reactivity with their homologous antigens. The reasons underlying the unexpected specificity of this S. aureus RIA for discriminating among sera from filarial and non-filarial infections were analysed qualitatively by immunoprecipitation techniques. It was found that use of the chloramine-T method for radioiodination resulted in preferential labelling of the low molecular weight (mol. wt) proteins (10-70,000 daltons) in the B. malayi adult somatic antigen and that these antigens were bound primarily by the filarial and not the non-filarial serum pools. These findings suggest that lower mol. wt helminth antigens may show greater species specificity than those with higher mol. wt, and those with higher mol. wt, greater cross-reactivity. If substantiated by further analysis, such results would have important implications for the subsequent isolation of diagnostically

  19. Evaluation of Bacteriological and Chemical Quality of Dialysis Water and Fluid in Isfahan, Central Iran

    Directory of Open Access Journals (Sweden)

    Ali SHAHRYARI

    2016-05-01

    Full Text Available Background: Chemical and microbial quality of water used in hemodialysis play key roles in a number of dialysis-related complications. In order to avoid the complications and to guarantee safety and health of patients therefore, vigorous control of water quality is essential. The objective of present study was to investigate the chemical and bacteriological characteristics of water used in dialysis centers of five hospitals in Isfahan, central Iran.Methods: A total of 30 water samples from the input of dialysis purification system and dialysis water were analyzed for chemical parameters. Heterotrophic plate count and endotoxin concentration of drinking water, dialysis water and dialysis fluid of 40 machines were also monitored over a 5-month period in 2011-2012.Results: Concentration of the determined chemicals (copper, zinc, sulfate, fluoride, chloramines and free chlorine did not exceed the recommended concentration by the Association for the Advancement of Medical Instrumentation (AAMI exclude lead, nitrate, aluminum and calcium. Furthermore, the magnesium; cadmium and chromium concentration exceeded the maximum level in some centers. No contamination with heterotrophic bacteria was observed in all samples, while the AMMI standard for endotoxin level in dialysis fluid (<2 EU/ml was achieved in 95% of samples.Conclusion: Dialysis water and fluid failed to meet the all chemical and bacteriological requirements for hemodialysis. To minimize the risk of contaminants for hemodialysis patients therefore, a water quality management program including monitoring, maintenance and development of water treatment system in hemodialysis centers is extremely important. In addition, an appropriate disinfection program is needed to guarantee better control of bacterial growth and biofilm formation. Keywords: Dialysis water, Dialysis fluid, Chemical quality, Endotoxin, Heterotrophic bacteria 

  20. Increased Myeloperoxidase Activity and Protein Nitration Are Indicators of Inflammation in Patients with Chagas' Disease▿

    Science.gov (United States)

    Dhiman, Monisha; Estrada-Franco, Jose Guillermo; Pando, Jasmine M.; Ramirez-Aguilar, Francisco J.; Spratt, Heidi; Vazquez-Corzo, Sara; Perez-Molina, Gladys; Gallegos-Sandoval, Rosa; Moreno, Roberto; Garg, Nisha Jain

    2009-01-01

    In this study, we investigated whether inflammatory responses contribute to oxidative/nitrosative stress in patients with Chagas' disease. We used three tests (enzyme-linked immunosorbent assay, immuno-flow cytometry, and STAT-PAK immunochromatography) to screen human serum samples (n = 1,481) originating from Chiapas, Mexico, for Trypanosoma cruzi-specific antibodies. We identified 121 subjects who were seropositive for T. cruzi-specific antibodies, a finding indicative of an 8.5% seroprevalence in the rural population from Chiapas. Seropositive and seronegative subjects were examined for plasma levels of biomarkers of inflammation, i.e., myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS), and xanthine oxidase (XOD), as well as for oxidative (advanced oxidation protein products [AOPPs]) and nitrosative (3-nitrotyrosine [3NT]) biomarkers. The seropositive subjects exhibited a significant increase in MPO activity and protein level, the indicator of neutrophil activation. Subsequently, a corresponding increase in AOPP contents, formed by MPO-dependent hypochlorous acid and chloramine formation, was noted in seropositive subjects. The plasma level of 3NT was significantly increased in seropositive subjects, yet we observed no change in XOD activity (O2− source) and nitrate/nitrite contents (denotes iNOS activation and NO production), which implied that direct peroxynitrite formation does not contribute to increased nitrosative damage in chagasic subjects. Instead, a positive correlation between increased MPO activity and protein 3NT formation was observed, which suggested to us that MPO-dependent formation of nitrylchloride that occurs in the presence of physiological NO and O2− concentrations contributes to protein nitration. Overall, our data demonstrate that T. cruzi-induced neutrophil activation is pathological and contributes to MPO-mediated collateral protein oxidative and nitrosative damage in human patients with Chagas' disease. Therapies

  1. Cut off values of laser fluorescence for different storage methods at different time intervals in comparison to frozen condition: A 1 year in vitro study

    Directory of Open Access Journals (Sweden)

    Rudra Kaul

    2014-01-01

    Full Text Available Aims: The aim of the following study is to evaluate the change in laser fluorescence (LF values for extracted teeth stored in different solutions over 1 year period, to give cut-off values for different storage media at different time intervals to get them at par with the in vivo conditions and to see which medium gives best results with the least change in LF values and while enhancing the validity of DIAGNOdent in research. Materials and Methods: Ninety extracted teeth selected, from a pool of frozen teeth, were divided into nine groups of 10 each. Specimens in Groups 1-8 were stored in 1% chloramine, 10% formalin, 10% buffered formalin, 0.02% thymol, 0.12% chlorhexidine, 3% sodium hypochlorite, a commercially available saliva substitute-Wet Mouth (ICPA Pharmaceuticals and normal saline respectively at 4°C. The last group was stored under frozen condition at −20°C without contact with any storage solution. DIAGNOdent was used to measure the change the LF values at day 30, 45, 60, 160 and 365. Statistical Analysis Used: The mean change in LF values in different storage mediums at different time intervals were compared using two-way ANOVA. Results: At the end of 1 year, significant decrease in fluorescence (P < 0.05 was observed in Groups 1-8. Maximum drop in LF values occurred between day 1 and 30. Group 9 (frozen specimens did not significantly change their fluorescence response. Conclusions: An inevitable change in LF takes place due to various storage media commonly used in dental research at different time intervals. The values obtained from our study can remove the bias caused by the storage media and the values of LF thus obtained can hence be conveniently extrapolated to the in vivo condition.

  2. Formation of N-nitrosamines from eleven disinfection treatments of seven different surface waters.

    Science.gov (United States)

    Zhao, Yuan-Yuan; Boyd, Jessica M; Woodbeck, Matthew; Andrews, Robert C; Qin, Feng; Hrudey, Steve E; Li, Xing-Fang

    2008-07-01

    Formation of nine N-nitrosamines has been investigated when seven different source waters representing various qualities were each treated with eleven bench-scale disinfection processes, without addition of nitrosamine precursors. These disinfection treatments included chlorine (OCl-), chloramine (NH2Cl), chlorine dioxide (ClO2), ozone (O3), ultraviolet (UV), advanced oxidation processes (AOP), and combinations. The total organic carbon (TOC) of the seven source waters ranged from 2 to 24 mg x L(-1). The disinfected water samples and the untreated source waters were analyzed for nine nitrosamines using a solid phase extraction and liquid chromatography-tandem mass spectrometry method. Prior to any treatment, N-nitrosodimethylamine (NDMA) was detected ranging from 0 to 53 ng x L(-1) in six of the seven source waters, and its concentrations increased in the disinfected water samples (0-118 ng x L(-1)). N-nitrosodiethylamine (NDEA), N-nitrosomorpholine (NMor), and N-nitrosodiphenylamine (NDPhA) were also identified in some of the disinfected water samples. NDPhA (0.2-0.6 ng x L(-1)) was formed after disinfection with OCl-, NH2Cl, O3, and MPUV/OCl-. NMEA was produced with OCl- and MPUV/OCl-, and NMor formation was associated with O3. In addition, UVtreatment alone degraded NDMA; however, UV/ OCl- and AOP/OCl- treatments produced higher amounts of NDMA compared to UV and AOP alone, respectively. These results suggest that UV degradation or AOP oxidation treatment may provide a source of NDMA precursors. This study demonstrates that environmental concentrations and mixtures of unknown nitrosamine precursors in source waters can form NDMA and other nitrosamines.

  3. Cut off values of laser fluorescence for different storage methods at different time intervals in comparison to frozen condition: A 1 year in vitro study

    Science.gov (United States)

    Kaul, Rudra; Kaul, Vibhuti; Farooq, Riyaz; Wazir, Nikhil Dev; Khateeb, Shafayat Ullah; Malik, Altaf H; Masoodi, Ajaz Amin

    2014-01-01

    Aims: The aim of the following study is to evaluate the change in laser fluorescence (LF) values for extracted teeth stored in different solutions over 1 year period, to give cut-off values for different storage media at different time intervals to get them at par with the in vivo conditions and to see which medium gives best results with the least change in LF values and while enhancing the validity of DIAGNOdent in research. Materials and Methods: Ninety extracted teeth selected, from a pool of frozen teeth, were divided into nine groups of 10 each. Specimens in Groups 1-8 were stored in 1% chloramine, 10% formalin, 10% buffered formalin, 0.02% thymol, 0.12% chlorhexidine, 3% sodium hypochlorite, a commercially available saliva substitute-Wet Mouth (ICPA Pharmaceuticals) and normal saline respectively at 4°C. The last group was stored under frozen condition at −20°C without contact with any storage solution. DIAGNOdent was used to measure the change the LF values at day 30, 45, 60, 160 and 365. Statistical Analysis Used: The mean change in LF values in different storage mediums at different time intervals were compared using two-way ANOVA. Results: At the end of 1 year, significant decrease in fluorescence (P < 0.05) was observed in Groups 1-8. Maximum drop in LF values occurred between day 1 and 30. Group 9 (frozen specimens) did not significantly change their fluorescence response. Conclusions: An inevitable change in LF takes place due to various storage media commonly used in dental research at different time intervals. The values obtained from our study can remove the bias caused by the storage media and the values of LF thus obtained can hence be conveniently extrapolated to the in vivo condition. PMID:24778506

  4. Role of the metabolism of parathyroid hormone. [Rats

    Energy Technology Data Exchange (ETDEWEB)

    Teitelbaum, Anne P.

    1978-01-01

    The heterogeneity of parathyroid hormone (PTH) in plasma has prompted investigations of the metabolism of PTH and its relationship to hormone action. The time course of tissue distribution and metabolism of electrolytically iodinated PTH (E-PTH) previously shown to retain biological activity was compared with that of inactive PTH iodinated with Chloramine-T (CT-PTH). Labeled PTH (0.4 ..mu..g) was injected in the saphenous veins of anesthetized rats which were sacrificed at 1, 3, 5, 10, and 20 min. Tissue extracts from kidney, liver, and serum were chromatographed to separate intact PTH from its metabolites. In the kidney, the initial rate of degradation of E-PTH was greater than that of CT-PTH. The difference in initial rates of metabolism may be due, in part, to receptor-specific hydrolysis on peritubular cell membranes which selectively act on biologically active PTH molecules. PTH-responsive adenyl cyclase activity in isolated kidney cortex plasma membranes was measured and PTH metabolism was monitored simultaneously. When degradation was completely blocked by histone f/sub 3/ (1 mg/ml), adenyl cyclase activity was significantly increased over control. In addition, when adenyl cyclase activity was negligible, the rate of PTH degradation by the membranes was not significantly diminished. Consistent with the in vivo data was the observation that E-PTH is metabolized by these membranes at a greater rate than CT-PTH. The data demonstrate the existence of a receptor-specific metabolism at sites which are independent of PTH receptor mediated adenyl cyclase activity.

  5. Theoretical Studies on F(-) + NH2Cl Reaction: Nucleophilic Substitution at Neutral Nitrogen.

    Science.gov (United States)

    Liu, Xu; Zhang, Jiaxu; Yang, Li; Sun, Rui

    2016-05-26

    The SN2 reactions at N center, denoted as SN2@N, has been recognized to play a significant role in carcinogenesis, although they are less studied and less understood. The potential energy profile for the model reaction of SN2@N, chloramine (NH2Cl) with fluorine anion (F(-)), has been characterized by extensive electronic structure calculations. The back-side SN2 channel dominates the reaction with the front-side SN2 channel becoming feasible at higher energies. The minimum energy pathway shows a resemblance to the well-known double-well potential model for SN2 reactions at carbon. However, the complexes involving nitrogen on both sides of the reaction barrier are characterized by NH---X (X = F or Cl) hydrogen bond and possess C1 symmetry, in contrast to the more symmetric ion-dipole carbon analogues. In the F(-) + NH2Cl system, the proton transfer pathway is found to become more competitive with the SN2 pathway than in the F(-) + CH3Cl system. The calculations reported here indicate that stationary point properties on the F(-) + NH2Cl potential energy surface are slightly perturbed by the theories employed. The MP2 and CAM-B3LYP, as well as M06-2X and MPW1K functionals give overall best agreement with the benchmark CCSD(T)/CBS energies for the major SN2 reaction channel, and are recommended as the preferred methods for the direct dynamics simulations to uncover the dynamic behaviors of the title reaction.

  6. Electrochemical disinfection of Escherichia coli in the presence and absence of primary sludge particulates.

    Science.gov (United States)

    Cui, Xiaofei; Quicksall, Andrew N; Blake, Allison B; Talley, Jeffrey W

    2013-09-01

    Electrochemical (EC) residual disinfection of Escherichia coli (E. coli) in the presence and absence of primary sludge particulates (PSPs) was studied. The kinetics followed a first-order rate law. When PSPs were absent, the EC residual disinfection rate coefficient (k) increased linearly with EC pretreatment energy (EC, 0-0.63 kWh/m(3)). However, with 143 mg PSPs/L, k first increased linearly with EC (0-0.28 kWh/m(3)) and then decreased linearly with EC (0.28-0.42 kWh/m(3)). H2O2 was detected during EC pretreatment in PSPs-free samples and the H2O2 concentration (CH) increased with EC (0-0.83 kWh/m(3)) linearly. Chloride was detected in PSPs aqueous samples (143 mg PSPs/L) and its concentration (CC) changed during EC pretreatment: initially, a decrease of CC was observed when EC increased from 0 to 0.28 kWh/m(3), followed by an increase of CC when EC increased 0.28-0.42 kWh/m(3). In both cases, k correlated to the initial post-EC chloride concentration (CCI) in an inverse linear relationship. This two-stage change of CC and k was caused by a combination of two reactions: anodic oxidation of chloride and the reaction of chloramines with excess chlorine. This paper explains the mechanisms underlying EC residual disinfection in the presence and absence of PSPs, and proposes a feasible strategy for EC disinfection when PSPs are present, an approach that could be useful in the treatment of combined sewage overflow (CSO).

  7. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell.

    Science.gov (United States)

    Huang, Xiao; Qu, Yan; Cid, Clément A; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C

    2016-04-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source.

  8. Compound-specific carbon, nitrogen, and hydrogen isotope analysis of N-nitrosodimethylamine in aqueous solutions.

    Science.gov (United States)

    Spahr, Stephanie; Bolotin, Jakov; Schleucher, Jürgen; Ehlers, Ina; von Gunten, Urs; Hofstetter, Thomas B

    2015-03-03

    Mitigation of N-nitrosodimethylamine (NDMA) and other hazardous water disinfection byproducts (DBP) is currently hampered by a limited understanding of DBP formation mechanisms. Because variations of the stable isotope composition of NDMA can potentially reveal reaction pathways and precursor compounds, we developed a method for the compound-specific isotope analysis (CSIA) of (13)C/(12)C, (15)N/(14)N, and (2)H/(1)H ratios of NDMA by gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS). Method quantification limits for the accurate isotope analysis of NDMA, N-nitrosodiethyl-, -dipropyl-, and -dibutylamine as well as N-nitrosopyrrolidine were between 0.18 to 0.60 nmol C, 0.40 to 0.80 nmol N, and 2.2 to 5.8 nmol H injected on column. Coupling solid phase extraction (SPE) to GC/IRMS enabled the precise quantification of C, N, and H isotope ratios of NDMA in aqueous samples at concentrations of 0.6 μM (45 μg L(-1)). We validated the proposed method with a laboratory experiment, in which NDMA was formed with stoichiometric yield (97 ± 4%) through chloramination of the pharmaceutical ranitidine (3 μM). δ(13)C and δ(2)H values of NDMA remained constant during NDMA formation while its δ(15)N increased due to a reaction at a N atom in the rate-limiting step of NDMA formation. The δ(2)H value of NDMA determined by SPE-GC/IRMS also corresponded well to the δ(2)H value of the N(CH3)2-group of ranitidine measured by quantitative deuterium nuclear magnetic resonance spectroscopy. This observation implies that the N(CH3)2-moiety of ranitidine is transferred to NDMA without being chemically altered and illustrates the accuracy of the proposed method.

  9. Radioimmunotherapy in refractory b-cell nonhodgkins lymphoma with I-131-labeled chimeric anti cd-20 c2b8 (I-131 rituximab): preliminary result

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hye Jin; Park, Yeon Hee; Kim, Sung Eun and others [Korea University Medical School, Seoul (Korea, Republic of)

    2005-07-01

    Recently, the native chimeric human-mouse anti CD-20 antibody IDEC-C2B8 (Rituximab) has been widely applied in NHL. This ongoing phase study was to evaluate whether radioimmunotherapy (RIT) with I-131 rituximab is effective in refractory B-cell NHL. Inclusion criteria were as follows: B-cell NHL with relapsed or refractory to primary standard therapy, measurable disease, adequate hematologic, renal, and hepatic function, informed consent. The rituximab (Mabthera, Roach) was radiolabeled with iodine-131(I-131) using a modified chloramine T method with high radiochemical purity (95%) and preservation of immuno-reactivity. All patients received loading doses of unlabeled rituximab (median, 40 mg: range, 20{approx}70 mg) immediately prior to administration of therapeutic dose (51.4{approx}152.2 MBq/kg), and then underwent gamma camera scan. 11 patients were enrolled (4 low-grade B-cell NHL, 7 DLBCL, median age 63 years). Patients had received a median of three prior chemotherapy regimens. The objective response rate was 36.4% (1 CR, 3 PRs). These all responses were observed in low-grade B-cell NHL, except one with DLBCL. Adverse events were primarily hematologic toxicities; the incidence of grade 3/4 neutropenia, thrombocytopenia, and anemia was 27.3%, 45.5%, and 18.2%, respectively. The treatment-related mortality was observed in one patient, who had been previously treated with high-dose chemotherapy plus TBI with autologous stem cell transplantation. RIT with I-131 rituximab seems to be effective tolerable in refractory low-grade B-cell NHL, although modest activity in refractory DLBCL. Further studies to define the efficacy of I-131 rituximab in DLBCL are warranted.

  10. Iodine-125 metaraminol: A new platelet specific labeling agent

    Energy Technology Data Exchange (ETDEWEB)

    Ohmomo, Y.; Yokoyama, A.; Kawaii, K.; Horiuchi, K.; Saji, H.; Torizuka, K.

    1984-01-01

    In the search for a platelet specific labeling agent, Metaraminol (MA), which is a sympatomimetic amine used for the treatment of hypotension, cardiogenic shock and well recognized as a drug actively incorporated and accumulated in platelet, attracted the authors' attention. Using the classical chloramine-T iodination method, a high labeling efficiency near 98%, reaching a specific activity up to about 1000 Ci/mmole was obtained. Upon the harvest of platelet, only as platelet rich plasma (PRP), the labeling with this radiopharmaceutical was easily performed by incubation at 37/sup 0/C for 10 min. Labeling efficiency as high as 63.0 +- 3.1% at 24 x 10/sup 8/ cells/ml was obtained. In in-vitro studies, the unaltered state of I-125 MA labeled platelet, with their cellular functions fully retained was demonstrated. Pharmacological study indicated a specific incorporation of I-125 MA by active transport system similar to that of 5-HT, along with passive diffusion. Then the in-vivo study carried out in rabbits with induced thrombi on the femoral artery, showed rather rapid disappearance of the I-125 MA labeled autologous platelet radioactivity, from circulating blood reaching as high thrombus-to-blood activity ratio as 19.8+-4.3 within 30 min post-administration. This new platelet labeling agent, I-125 MA, has many advantages over the use of IN-111 oxine and holds considerable promise for thrombus imaging with single photon emission CT upon the availability of I-123 MA.

  11. (/sup 125/I) radioiodinated metaraminol: A new platelet-specific labeling agent

    Energy Technology Data Exchange (ETDEWEB)

    Ohmomo, Y.; Yokoyama, A.; Kawai, K.; Arano, Y.; Horiuchi, K.; Tanaka, C.; Saji, H.; Torizuka, K.

    1985-03-01

    In our search for a platelet-specific labeling agent, metaraminol (MA), a low-toxic pharmaceutical for the treatment of hypotension and cardiogenic shock, attracted our attention. Its active incorporation and accumulation by platelets have been recognized. At first, the preparation of /sup 125/I radioiodinated metaraminol (/sup 125/I-MA) was carried out using the chloramine-T method. Then, upon the harvest of platelets as platelet-rich plasma (PRP), their labeling with this new radiopharmaceutical was easily performed by incubation for 10 min at 37/sup 0/C. The cell-labeling efficiency was dependent on cell density, reaching 63.0%+-3.1% at 2.4x10/sup 9/ cells/ml. The specific incorporation of /sup 125/I-MA by an active transport system similar to that of 5-hydroxytryptamine (5-HT) as well as by passive diffusion was demonstrated. In vitro studies, the unaltered state of /sup 125/I-MA-labeled platelets with their cellular functions fully retained was estimated. In vivo studies carried out in rabbits with induced thrombi in the femoral artery showed a rather rapid disappearance of the radioactivity from circulating blood, reaching a high thrombus-to-blood activity ratio of 19.8+-4.3 within 30 min of the administration of /sup 125/I-MA-labeled autologous platelets. Thus, with the potential availability of /sup 123/I, /sup 123/I-MA-labeled platelets appear to be a promising agent for thrombus imaging using single-emission computed tomography (CT) studies.

  12. Transformation of acetaminophen during water chlorination treatment: kinetics and transformation products identification.

    Science.gov (United States)

    Cao, Fei; Zhang, Mengtao; Yuan, Shoujun; Feng, Jingwei; Wang, Qiquan; Wang, Wei; Hu, Zhenhu

    2016-06-01

    As a high-consumption drug in the world, acetaminophen (AAP) has been widely detected in natural waters and wastewaters. Its reactivity and the transformation products formed during chlorination may greatly threaten the safety of drinking water. The reaction kinetics of AAP during chlorination was investigated in this study. The results showed that the reaction kinetics could be well described with a kinetics model of -d[AAP]/dt = k app[AAP]t (0.63)[Cl2]t (1.37). The values of apparent rate constant (k app) were dependent on reaction temperature, ammonium, and pH. With the increase in reaction temperature from 5.0 ± 1.0 to 40.0 ± 1.0 °C, the removal efficiency of AAP increased from 60 to 100 %. When ammonium was present in the solution at 2.0 mg/L, the transformation of AAP was inhibited due to the rapid formation of chloramines. The maximum of k app was 0.58 × 10(2) M(-1) · min(-1) at pH 9.0, and the minimum was 0.27 M(-1) · min(-1) at pH 11.0. A low mineralization of AAP (about 7.2 %) with chlorination was observed through TOC analysis, implying the formation of plenty of transformation products during chlorination. The main transformation products, hydroquinone and two kinds of chlorinated compounds, monochlorinated acetaminophen and dichlorinated acetaminophen, were detected in gas chromatography-mass spectrometry analysis.

  13. Monitoring of Coliforms and chlorine residual in water distribution network of Rawalpindi, Pakistan.

    Science.gov (United States)

    Farooq, Shaukat; Hashmi, Imran; Qazi, Ishtiaq A; Qaiser, Sara; Rasheed, Sajida

    2008-05-01

    The present study was undertaken to examine the drinking water quality of Rawal Treatment Plant, Rawalpindi and its distribution network by collecting samples from eight different locations. The aim was to determine potential relationship between the presence of microorganisms and chlorine residual in the distribution network. Quantification of chlorine residual, turbidity, standard plate count (SPC), fecal and total coliforms by Most Probable Number (MPN) was performed. Three different forms of chlorine were measured at each sampling station such as free chlorine, residual chlorine, chloramines and total chlorine residual. A critical evaluation of data presented indicated that pH generally ranged from 7.02-7.30; turbidity varied from 0.34-2.79 NTU; conductivity fluctuated from 359-374 microS/cm; and TDS values were found to be ranging between 180-187 mg/l. Station # 7 was found to be most contaminated. The value of total chlorine was found to be 0.86 to1.7 mg/l at Station # 3 and 6, respectively. Highest standard plate count was 62 CFU/ml at Station # 7. Total coliforms were less than 1.1 MPN/100 ml at almost most of the stations except at Station # 3 where it was found to be greater than 23.0 MPN /100 ml. Overall aim of this study is to create awareness about contamination of drinking water in the water distribution networks and to make recommendations to provincial agencies such as EPA, CDA and WASA that regular monitoring should be carried out to ensure that the chlorine residual is available at consumer end.

  14. Artificial sweetener sucralose in U.S. drinking water systems.

    Science.gov (United States)

    Mawhinney, Douglas B; Young, Robert B; Vanderford, Brett J; Borch, Thomas; Snyder, Shane A

    2011-10-15

    The artificial sweetener sucralose has recently been shown to be a widespread of contaminant of wastewater, surface water, and groundwater. In order to understand its occurrence in drinking water systems, water samples from 19 United States (U.S.) drinking water treatment plants (DWTPs) serving more than 28 million people were analyzed for sucralose using liquid chromatography tandem mass spectrometry (LC-MS/MS). Sucralose was found to be present in source water of 15 out of 19 DWTPs (47-2900 ng/L), finished water of 13 out of 17 DWTPs (49-2400 ng/L) and distribution system water of 8 out of the 12 DWTPs (48-2400 ng/L) tested. Sucralose was only found to be present in source waters with known wastewater influence and/or recreational usage, and displayed low removal (12% average) in the DWTPs where finished water was sampled. Further, in the subset of DWTPs with distribution system water sampled, the compound was found to persist regardless of the presence of residual chlorine or chloramines. In order to understand intra-DWTP consistency, sucralose was monitored at one drinking water treatment plant over an 11 month period from March 2010 through January 2011, and averaged 440 ng/L in the source water and 350 ng/L in the finished water. The results of this study confirm that sucralose will function well as an indicator compound for anthropogenic influence on source, finished drinking and distribution system (i.e., tap) water, as well as an indicator compound for the presence of other recalcitrant compounds in finished drinking water in the U.S.

  15. Removal of geosmin and 2-methylisoborneol by biological filtration.

    Science.gov (United States)

    Elhadi, S L N; Huck, P M; Slawson, R M

    2004-01-01

    The quality of drinking water is sometimes diminished by the presence of certain compounds that can impart particular tastes or odours. One of the most common and problematic types of taste and odour is the earthy/musty odour produced by geosmin (trans-1, 10-dimethyl-trans-9-decalol) and MIB (2-methylisoborneol). Taste and odour treatment processes including powdered activated carbon, and oxidation using chlorine, chloramines, potassium permanganate, and sometimes even ozone are largely ineffective for reducing these compounds to below their odour threshold concentration levels. Ozonation followed by biological filtration, however, has the potential to provide effective treatment. Ozone provides partial removal of geosmin and MIB but also creates other compounds more amenable to biodegradation and potentially undesirable biological instability. Subsequent biofiltration can remove residual geosmin and MIB in addition to removing these other biodegradable compounds. Bench scale experiments were conducted using two parallel filter columns containing fresh and exhausted granular activated carbon (GAC) media and sand. Source water consisted of dechlorinated tap water to which geosmin and MIB were added, as well as, a cocktail of easily biodegradable organic matter (i.e. typical ozonation by-products) in order to simulate water that had been subjected to ozonation prior to filtration. Using fresh GAC, total removals of geosmin ranged from 76 to 100% and total MIB removals ranged from 47% to 100%. The exhausted GAC initially removed less geosmin and MIB but removals increased over time. Overall the results of these experiments are encouraging for the use of biofiltration following ozonation as a means of geosmin and MIB removal. These results provide important information with respect to the role biofilters play during their startup phase in the reduction of these particular compounds. In addition, the results demonstrate the potential biofilters have in responding to

  16. Hypochlorite-induced damage to plasma and proteins: formation of nitrogen-centred radicals and their role in protein oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, C.L.; Davies, M.J. [Heart Research Institute, Camperdown, NSW (Australia)

    1998-12-31

    The respiratory burst of activated phagocyte cells results in the generation of hypochlorite (HOCl) via the release of the hydrogen peroxide and the enzyme myeloperoxidase. Little information is available about the mechanisms and intermediates involved in these reactions. Electron paramagnetic resonance (EPR) spectroscopy with spin trapping has been employed to identify radicals formed in fresh human plasma and isolated proteins and peptides on treatment with HOCI. Reaction of plasma with HOCI in the presence of a spin trap gives broad, anisotropic radical adducts consistent with the formation of large, slowly-tumbling, protein-derived radicals. The identity of the plasma-derived radical adducts was investigated further by the incubation of the pre-formed adducts with the non-specific proteolytic enzyme pronase. This treatment gave sharper, signals consistent with the release of more mobile, low-molecular-weight spin adducts from the initial protein-derived adducts. The hyperfine couplings of these sharper signals are characteristic of the formation of nitrogen-centred radical adducts. Similar or identical species are observed on treatment with isolated human serum albumin, suggesting that this is a major site of HOCI-induced oxidation. Reaction of HOCI-treated plasma or isolated proteins/peptides with excess methionine eliminates radical formation, consistent with lysine-derived chloramines (via homolysis or heterolysis of N-CI bonds) being the radical source. The effect of HOCI on the structural integrity of the plasma proteins was investigated by SDS-PAGE. It was demonstrated that incubation of HOCI-treated plasma or proteins, after removal of excess oxidant, resulted in a time- and HOCI-dependent fragmentation of the proteins. No evidence was obtained for the presence of either discrete fragments or aggregated material. This suggests that the reaction of HOCI with plasma proteins results in the formation of a large number of random fragments. Treatment with

  17. Occurrence and profiling of multiple nitrosamines in source water and drinking water of China.

    Science.gov (United States)

    Wang, Wanfeng; Yu, Jianwei; An, Wei; Yang, Min

    2016-05-01

    The occurrence of multiple nitrosamines was investigated in 54 drinking water treatment plants (DWTPs) from 30 cities across major watersheds of China, and the formation potential (FP) and cancer risk of the dominant nitrosamines were studied for profiling purposes. The results showed that N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodi-n-butylamine (NDBA) were the most abundant in DWTPs, and the concentrations in source water and finished water samples were not detected (ND) -53.6ng/L (NDMA), ND -68.5ng/L (NDEA), ND -48.2ng/L (NDBA). The frequencies of detection in source waters were 64.8%, 61.1% and 51.8%, and 57.4%, 53.7%, and 37% for finished waters, respectively. Further study indicated that the FPs of the three main nitrosamines during chloramination were higher than those during chlorination and in drinking water. The results of Principal Components Analysis (PCA) showed that ammonia was the most closely associated factor in nitrosamine formation in the investigated source water; however, there was no significant correlation between nitrosamine-FPs and the values of dominant water-quality parameters. The advanced treatment units (i.e., ozonation and biological activated carbon) used in DWTPs were able to control the nitrosamine-FPs effectively after disinfection. The target pollutants posed median and maximum cancer risks of 2.99×10(-5) and 35.5×10(-5) to the local populations due to their occurrence in drinking water.

  18. Outbreaks of Short-Incubation Ocular and Respiratory Illness Following Exposure to Indoor Swimming Pools

    Science.gov (United States)

    Bowen, Anna B.; Kile, James C.; Otto, Charles; Kazerouni, Neely; Austin, Connie; Blount, Benjamin C.; Wong, Hong-Nei; Beach, Michael J.; Fry, Alicia M.

    2007-01-01

    Objectives Chlorination destroys pathogens in swimming pool water, but by-products of chlorination can cause human illness. We investigated outbreaks of ocular and respiratory symptoms associated with chlorinated indoor swimming pools at two hotels. Measurements We interviewed registered guests and companions who stayed at hotels X and Y within 2 days of outbreak onset. We performed bivariate and stratified analyses, calculated relative risks (RR), and conducted environmental investigations of indoor pool areas. Results Of 77 guests at hotel X, 47 (61%) completed questionnaires. Among persons exposed to the indoor pool area, 22 (71%) of 31 developed ocular symptoms [RR = 24; 95% confidence interval (CI), 1.5–370], and 14 (45%) developed respiratory symptoms (RR = 6.8; 95% CI, 1.0–47) with a median duration of 10 hr (0.25–24 hr). We interviewed 30 (39%) of 77 registered persons and 59 unregistered companions at hotel Y. Among persons exposed to the indoor pool area, 41 (59%) of 69 developed ocular symptoms (RR = 24; 95% CI, 1.5–370), and 28 (41%) developed respiratory symptoms (RR = 17; 95% CI, 1.1–260) with a median duration of 2.5 hr (2 min–14 days). Four persons sought medical care. During the outbreak, the hotel X’s ventilation system malfunctioned. Appropriate water and air samples were not available for laboratory analysis. Conclusions and relevance to professional practice Indoor pool areas were associated with illness in these outbreaks. A large proportion of bathers were affected; symptoms were consistent with chloramine exposure and were sometimes severe. Improved staff training, pool maintenance, and pool area ventilation could prevent future outbreaks. PMID:17384776

  19. N-Chlorotaurine and ammonium chloride: an antiseptic preparation with strong bactericidal activity.

    Science.gov (United States)

    Gottardi, Waldemar; Arnitz, Roland; Nagl, Markus

    2007-04-20

    The bactericidal activity of the endogenous antiseptic N-chlorotaurine (NCT) is significantly enhanced in the presence of ammonium chloride which induces the formation of monochloramine (NH(2)Cl) whose strong bactericidal activity is well known. In this study the properties of NCT plus ammonium chloride have been investigated. The reaction of active chlorine compounds like chloramine-T (N-chlorotoluene-sulfonamide sodium), chloroisocyanuric acid derivatives, hypochlorites (NaOCl, CaOCl(2)) with ammonium chloride did not stop at the stage of monochloramine, and the pungent smelling by-products di- and trichloramine, NHCl(2) and NCl(3), were also formed. This was not the case with NCT where only monochloramine was generated. The equilibrium constant of the reaction of NCT with ammonium was found to be [Formula: see text] , which allows to estimate the equilibrium concentration of monochloramine in aqueous solutions of NCT and ammonium chloride. At concentrations each ranging between 0.01% and 1.0% it comes to [NH(2)Cl]=3.5-254 ppm. As an unexpected result the monochloramine containing formulation turned out to be most stable in plain water without buffer additives. Quantitative killing assays revealed complete inactivation of 10(6) to 10(7)CFU/mL of seven bacterial strains by 0.1% NCT plus 0.1% ammonium chloride within 5 min, while with plain 0.1% NCT an incubation time of 2-4h was needed to achieve the same effect. The highly significant increase of bactericidal activity (200-300-fold) could be assigned to the presence of monochloramine which could be isolated by vacuum distillation. Aqueous solutions of NCT and ammonium chloride provide a highly effective and well tolerable antiseptic preparation appropriate to a treatment cycle of at least 1 month if stored in the refrigerator.

  20. Occurrence of selected aliphatic amines in source water of major cities in China

    Institute of Scientific and Technical Information of China (English)

    Haifeng Zhang; Shuoyi Ren; Jianwei Yu; Min Yang

    2012-01-01

    The formation of toxic nitrogenous disinfection byproducts (N-DBPs),such as nitrosamines,halonitromethanes and haloacetonitriles,from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health.This study revealed the occurrence of 17 aliphatic amines,some of which have been confirmed to be the precursors of N-DBPs,in source water across China.A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples.In total,37 source water samples from the capital cities of 20 provinces were collected for the survey.Among the 17 amines,14 were detected with an average frequency of detection of 36%.The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine (100%,24.82 μg/L),methylamine (78%,0.92 μg/L),N-methylethylamine (70%,8.84 μg/L),propylamine (59%,10.69 μg/L),diethylamine (54%,3.76 μg/L),N-methylbutylamine (35%,3.07 μg/L),N-ethylpropylamine (35%,0.52 μg/L),and piperidine (32%,2.35 μg/L).This is the first large scale survey of the aliphatic amines occurrence in source water in the world.The wide presence of nitrosamine precursors like dimethylamine,N-methylethylamine and diethylamine,and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water.

  1. Chlorination of parabens: reaction kinetics and transformation product identification.

    Science.gov (United States)

    Mao, Qianhui; Ji, Feng; Wang, Wei; Wang, Qiquan; Hu, Zhenhu; Yuan, Shoujun

    2016-11-01

    The reactivity and fate of parabens during chlorination were investigated in this work. Chlorination kinetics of methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) were studied in the pH range of 4.0 to 11.0 at 25 ± 1 °C. Apparent rate constants (k app) of 9.65 × 10(-3) M(-0.614)·s(-1), 1.77 × 10(-2) M(-1.019)·s(-1), 2.98 × 10(-2) M(-0.851)·s(-1), and 1.76 × 10(-2) M(-0.860)·s(-1) for MeP, EtP, PrP, and BuP, respectively, were obtained at pH 7.0. The rate constants depended on the solution pH, temperature, and NH4(+) concentration. The maximum k app was obtained at pH 8.0, and the minimum value was obtained at pH 11.0. The reaction rate constants increased with increasing temperature. When NH4(+) was added to the solution, the reaction of parabens was inhibited due to the rapid formation of chloramines. Two main transformation products, 3-chloro-parabens and 3,5-dichloro-parabens, were identified by GC-MS and LCMS-IT-TOF, and a reaction pathway was proposed. Dichlorinated parabens accumulated in solution, which is a threat to human health and the aqueous environment.

  2. Chemical contaminants in swimming pools: Occurrence, implications and control.

    Science.gov (United States)

    Teo, Tiffany L L; Coleman, Heather M; Khan, Stuart J

    2015-03-01

    A range of trace chemical contaminants have been reported to occur in swimming pools. Current disinfection practices and monitoring of swimming pool water quality are aimed at preventing the spread of microbial infections and diseases. However, disinfection by-products (DBPs) are formed when the disinfectants used react with organic and inorganic matter in the pool. Additional chemicals may be present in swimming pools originating from anthropogenic sources (bodily excretions, lotions, cosmetics, etc.) or from the source water used where trace chemicals may already be present. DBPs have been the most widely investigated trace chemical contaminants, including trihalomethanes (THMs), haloacetic acids (HAAs), halobenzoquinones (HBQs), haloacetonitriles (HANs), halonitromethanes (HNMs), N-nitrosamines, nitrite, nitrates and chloramines. The presence and concentrations of these chemical contaminants are dependent upon several factors including the types of pools, types of disinfectants used, disinfectant dosages, bather loads, temperature and pH of swimming pool waters. Chemical constituents of personal care products (PCPs) such as parabens and ultraviolet (UV) filters from sunscreens have also been reported. By-products from reactions of these chemicals with disinfectants and UV irradiation have been reported and some may be more toxic than their parent compounds. There is evidence to suggest that exposure to some of these chemicals may lead to health risks. This paper provides a detailed review of various chemical contaminants reported in swimming pools. The concentrations of chemicals present in swimming pools may also provide an alternative indicator to swimming pool water quality, providing insights to contamination sources. Alternative treatment methods such as activated carbon filtration and advanced oxidation processes may be beneficial in improving swimming pool water quality.

  3. Radioimmunoimaging of osteogenic sarcoma xenografts in nude mice using monoclonal antibodies to osteogenic sarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Sakahara, H.; Endo, K.; Nakashima, T.; Koizumi, M.; Ohta, H.; Kunimatsu, M.; Torizuka, K.; Nakamura, T.; Tanaka, H.; Kotoura, Y.

    1985-05-01

    The authors have developed several monoclonal antibodies against human osteogenic sarcoma, one of which; OST7 (IgGl) selectively localized in osteogenic sarcoma xenografts in nude mice. In the present study, F(ab')/sub 2/ fragment was compared with whole IgG and those labeled with In-111 as well as I-131 were used as a radiotracer for the scintigraphic imaging of tumors. IgC and F(ab')/sub 2/ were labeled with I-131 using chloramine-T method and injected into nude mice bearing human osteogenic sarcoma. Scintigrams at day 2 clearly delineated the site of tumors with almost no radioactivity in other organs with F(ab')/sub 2/, which yielded much better images than whole IgG. Tumor-to-blood ratio of 6.09-27.87 was obtained at day 2 using F(ab')/sub 2/, whereas it was 0.76-1.12 at day 2 and 2.05-3.27 at day 7 with IgG. I-131 labeled nonspecific F(ab')/sub 2/ or IgG resulted in no or very low tumor uptake with tumor-to-blood ratio of 0.94-1.18 at day 2 for F(ab')/sub 2/ and 0.67-0.76 at day 7 for IgG, respectively. In-111 labeled F(ab')/sub 2/ fragment of OST7, which was prepared using DTPA as a bifunctional chelate, also showed a high tumor accumulation with tumor-to-blood ratio of 11.67-17.54 at day 2, but higher background activity in the liver and kidney was observed than I-131 labeled one. These results indicate that F(ab')/sub 2/ fragment of OST7 labeled with either I-131 or In-111, has a great potential for the radioimmunoimaging of osteogenic sarcoma.

  4. Simple spectrophotometric and titrimetric methods for the determination of sulfur dioxide.

    Science.gov (United States)

    Yogendra Kumar, M S; Gowtham, M D; Mahadevaiah; Agendrappa, G

    2006-05-01

    The proposed work describes a simple spectrophotmetric as well as a titrimetric method to determine sulfur dioxide. The spectrophotometric method is based on a redox reaction between sulfur dioxide and iodine monochloride obtained from iodine with chloramine-T in acetic acid. The reagent iodine monochloride oxidizes sulfur dioxide to sulfate, thereby reducing itself to iodine. Thus liberated iodine will also oxidize sulfur dioxide and reduce itself to iodide. The obtained iodide is expected to combine with iodine to form a brown-colored homoatomictriiodide anion (460 nm), which forms an ion-pair with the sulfonamide cation, providing exceptional color stability to the system under an acidic condition, and is quantitatively relatd to sulfur dioxide. The system obeys Beer's law in the range 5 - 100 microg of sulfur dioxide in a final volume of 10 ml. The molar absorptivity is 5.03 x 10(3) l mol(-1)cm(-1), with a relative standard deviation of 3.2% for 50 microg of sulfur dioxide (n = 10). In the titrimetric method, the reagent iodine monochloride was reduced with potassium iodide (10%) to iodine, which oxidized sulfur dioxide to sulfate, and excess iodine was determined with a thiosulfate solution. The volume difference of thiosulfate with the reagent and with the sulfur dioxide determined the sulfur dioxide. Reproducible and accurate results were obtained in the range of 0.1 - 1.5 mg of sulfur dioxide with a relative standard deviation of 1.2% for 0.8 mg of sulfur dioxide (n = 10).

  5. 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.

  6. The structure of flavin-dependent tryptophan 7-halogenase RebH

    Energy Technology Data Exchange (ETDEWEB)

    Bitto, Eduard; Huang, Yu; Bingman, Craig A.; Singh, Shanteri; Thorson, Jon S.; Phillips, Jr., George N. (UW)

    2010-02-19

    Enzyme catalyzed regio- and stereo-specific halogenations influence the biological activity of a diverse array of therapeutically important natural products, including the antibiotics vancomycin and chloramphenicol as well as the anticancer agents calicheamicin and rebeccamycin. The major class of enzymes responsible for this challenging synthetic reaction, the flavin-dependent halogenases, catalyzes the formation of carbon-halogen bonds using flavin, a halide ion (Cl{sup -}, Br{sup -} or I{sup -}), and O{sub 2}. Recent mechanistic and structural advances achieved with the model flavin-dependent tryptophan 7-halogenases PrnA and RebH have greatly enhanced the level of understanding of this unique reaction. According to these studies, the mechanism for tryptophan halogenation proceeds via FAD(C4a)-OOH activation of a chloride ion into the transient chlorinating species HOCl. The key evidence for the requirement of a transient chlorinating species is the discovery that a {approx}10-{angstrom}-long tunnel separates FAD and tryptophan in the ligand-bound form of PrnA. In a recent compelling study to elucidate the strategy by which RebH controls this highly reactive and indiscriminant oxidant, a Lys79-{var_epsilon}NH-Cl chloramine intermediate was implicated as the actual chlorinating species within RebH and a structural investigation of RebH was reported. Here we report our independent structural analysis of Lechevalieria aerocolonigenes RebH (Uni-Prot accession number Q8KHZ8, 530 amino acids) in its apo-form as well as in a complex with both tryptophan and FAD.

  7. Disinfection by-products and microbial contamination in the treatment of pool water with granular activated carbon.

    Science.gov (United States)

    Uhl, W; Hartmann, C

    2005-01-01

    For swimming pools, it is generally agreed that free chlorine levels have to be maintained to guarantee adequate disinfection. Recommended free chlorine levels can vary between 0.3 and 0.6 mg/L in Germany and up to 3 mg/L in other countries. Bathers introduce considerable amounts of organic matter, mainly in the form of such as urine and sweat, into the pool water. As a consequence, disinfection byproducts (DBPs) are formed. Regulations in Germany recommend levels of combined chlorine of less than 0.2 mg/L and levels of trihalomethanes (THMs) of less than 20 microg/L. Haloacetic acids (HAAs), haloacetonitriles (HANs), chloropicrin and chloral hydrate are also detected in considerable amounts. However, these compounds are not regulated yet. Swimming pool staff and swimmers, especially athletes, are primarily exposed to these byproducts by inhalation and/or dermal uptake. In Germany, new regulations for swimming pool water treatment generally require the use of activated carbon. In this project, three different types of granular activated carbon (GAC) (one standard GAC, two catalytic GACs) are compared for their long time behaviour in pool water treatment. In a pilot plant operated with real swimming pool water, production and removal of disinfection byproducts (THMs, HAAs, AOXs), of biodegradable substances (AOC), of bacteria (Pseudomonas aeruginosa, Legionella, coliforms, HPC) as well as the removal of chlorine and chloramines are monitored as function of GAC bed depth. Combined chlorine penetrates deeper in the filter bed than free chlorine does. However, both, free and combined chlorine removal efficiencies decrease over the time of filter operation. The decreases of removal efficiencies are also observed for parameters such as dissolved organic carbon, spectral absorption coefficient, adsorbable organic carbon and most of the disinfection byproducts. However, THMs, especially chloroform are produced in the filter bed. The GAC beds were contaminated microbially

  8. Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products.

    Science.gov (United States)

    Hrudey, Steve E; Backer, Lorraine C; Humpage, Andrew R; Krasner, Stuart W; Michaud, Dominique S; Moore, Lee E; Singer, Philip C; Stanford, Benjamin D

    2015-01-01

    Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches.

  9. DRINKING WATER DISINFECTION BYPRODUCTS:CHEMICAL CHARACTERIZATION AND TOXICITY%饮用水消毒副产物:化学特征与毒性

    Institute of Scientific and Technical Information of China (English)

    赵玉丽; 李杏放

    2011-01-01

    Disinfection of drinking water is essential to and effective for the prevention of water-borne diseases.While achieving deactivation of microbial pathogens to minimize the acute risk, an unintentional consequence is the formation of disinfection byproducts (DBPs) resulting from reactions of disinfectants with natural organic materials (NOMs) in water. Epidemiological studies show potential associations of increased risk of bladder cancer and adverse health effects with DBPs. Balancing microbial risk with chemical risk is challenging for public health protection. Currently, the most commonly used disinfectants are chlorine, chlorine dioxide,chloramines and ozone. Here we provide an overview of chemical characterization, toxicity and analytical methods of 10 classes of DBPs, including trihalomethanes ( THMs), haloacefic acids ( HAAs), bromate ( BrO3- ), chlorite ( ClO2- ), haloacetonitriles (HANs), mutagen X (MX), halonitromethane ( HNMs), iodo acids (IAs), N-nitrosodimethylamines (NMs) and halobenzoquinones (HBQs). We will discuss the challenges and opportunities in the research of DBPs and health effects.%饮用水消毒过程中消毒剂与天然有机物(NOMs)反应生成消毒副产物(DBPs).本文针对氯、氯胺、二氧化氯、臭氧4种主要消毒方式产生的消毒副产物,综述了10类DBPs的化学特性、毒性和分析方法.具体包括:三卤甲烷(THMs)、卤乙酸(HAAs)、溴酸盐(BrO3-)、亚氯酸盐(CIO2-)、卤乙腈(HANs)、致诱变化合物(MX)、卤代硝基甲烷(HNMs)、碘代酸(Ias)、亚硝胺(NMs)以及卤代对苯醌(HBQs).

  10. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell

    Science.gov (United States)

    Huang, Xiao; Qu, Yan; Cid, Clément A.; Finke, Cody; Hoffmann, Michael R.; Lim, Keahying; Jiang, Sunny C.

    2016-01-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [•OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. PMID:26854604

  11. Free Radical Chemistry of Disinfection Byproducts 1: Kinetics of Hydrated Electron and Hydroxyl Radical Reactions with Halonitromethanes in Water

    Energy Technology Data Exchange (ETDEWEB)

    B. J. Mincher; R. V. Fox; S. P. Mezyk; T. Helgeson; S. K. Cole; W. J. Cooper; P. R. Gardinali

    2006-01-01

    Halonitromethanes are disinfection-byproducts formed during ozonation and chlorine/chloramine treatment of waters that contain bromide ion and natural organic matter. In this study, the chemical kinetics of the free-radical-induced degradations of a series of halonitromethanes were determined. Absolute rate constants for hydroxyl radical, OH, and hydrated electron, eaq-, reaction with both chlorinated and brominated halonitromethanes were measured using the techniques of electron pulse radiolysis and transient absorption spectroscopy. The bimolecular rate constants obtained, k (M-1 s-1), for eaq-/OH, respectively, were the following: chloronitromethane (3.01 ± 0.40) × 1010/(1.94 ± 0.32) × 108; dichloronitromethane (3.21 ± 0.17) × 1010/(5.12 ± 0.77) × 108; bromonitromethane (3.13 ± 0.06) × 1010/(8.36 ± 0.57) × 107; dibromonitromethane (3.07 ± 0.40) × 1010/(4.75 ± 0.98) × 108; tribromonitromethane (2.29 ± 0.39) × 1010/(3.25 ± 0.67) × 108; bromochloronitromethane (2.93 ± 0.47) × 1010/(4.2 ± 1.1) × 108; bromodichloronitromethane (2.68 ± 0.13) × 1010/(1.02 ± 0.15) × 108; and dibromochloronitromethane (2.95 ± 0.43) × 1010 / (1.80 ± 0.31) × 108 at room temperature and pH ~7. Comparison data were also obtained for hydroxyl radical reaction with bromoform (1.50 ± 0.05) × 108, bromodichloromethane (7.11 ± 0.26) × 107, and chlorodibromomethane (8.31 ± 0.25) × 107 M-1 s-1, respectively. These rate constants are compared to recently obtained data for trichloronitromethane and bromonitromethane, as well as to other established literature data for analogous compounds.

  12. Acetonitrile and N-Chloroacetamide Formation from the Reaction of Acetaldehyde and Monochloramine.

    Science.gov (United States)

    Kimura, Susana Y; Vu, Trang Nha; Komaki, Yukako; Plewa, Michael J; Mariñas, Benito J

    2015-08-18

    Nitriles and amides are two classes of nitrogenous disinfection byproducts (DBPs) associated with chloramination that are more cytotoxic and genotoxic than regulated DBPs. Monochloramine reacts with acetaldehyde, a common ozone and free chlorine disinfection byproduct, to form 1-(chloroamino)ethanol. Equilibrium (K1) and forward and reverse rate (k1,k-1) constants for the reaction between initial reactants and 1-(chloroamino)ethanol were determined between 2 and 30 °C. Activation energies for k1 and k-1 were 3.04 and 45.2 kJ·mol(-1), respectively, and enthalpy change for K1 was -42.1 kJ·mol(-1). In parallel reactions, 1-(chloroamino)ethanol (1) slowly dehydrated (k2) to (chloroimino)ethane that further decomposed to acetonitrile and (2) was oxidized (k3) by monochloramine to produce N-chloroacetamide. Both reactions were acid/base catalyzed, and rate constants were characterized at 10, 18, and 25 °C. Modeling for drinking water distribution system conditions showed that N-chloroacetamide and acetonitrile concentrations were 5-9 times higher at pH 9.0 compared to 7.8. Furthermore, acetonitrile concentration was found to form 7-10 times higher than N-chloroacetamide under typical monochloramine and acetaldehyde concentrations. N-chloroacetamide cytotoxicity (LC50 = 1.78 × 10(-3) M) was comparable to dichloroacetamide and trichloroacetamide, but less potent than N,2-dichloroacetamide and chloroacetamide. While N-chloroacetamide was not found to be genotoxic, N,2-dichloroacetamide genotoxic potency (5.19 × 10(-3) M) was on the same order of magnitude as chloroacetamide and trichloroacetamide.

  13. Identifying unknown by-products in drinking water using comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry and in silico toxicity assessment.

    Science.gov (United States)

    Li, Chunmei; Wang, Donghong; Li, Na; Luo, Qian; Xu, Xiong; Wang, Zijian

    2016-11-01

    Improvements in extraction and detection technologies have increased our abilities to identify new disinfection by-products (DBPs) over the last 40 years. However, most previous studies combined DBP identification and measurement efforts with toxicology to address concerns on a few expected DBPs, making it difficult to better define the health risk from the individual DBPs. In this study, a nontargeted screening method involving comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry (GC × GC-qMS) combined with OECD QSAR Toolbox Ver. 3.2 was developed for identifying and prioritizing of volatile and semi-volatile DBPs in drinking water. The method was successfully applied to analyze DBPs formed during chlorination, chloramination or ozonation of the raw water. Over 500 compounds were tentatively identified in each sample, showing the superior performance of this analytical technique. A total of 170 volatile and semi-volatile DBPs representing fourteen chemical classes were then identified, according to the criteria that the DBP was presented in the duplicate treated samples. The genotoxicity and carcinogenicity of the DBPs were evaluated using Toolbox, and 58 DBPs were found to be actual or potential genotoxicants. The accuracy of the compound identification was determined by comparing 47 identified compounds with commercially available standards. About 90% (41 of the 47) of the compounds that were automatically identified using the library were correct. The results show that GC×GC-qMS coupled with a quantitative structure-activity relationship model is a powerful and fast nontargeted screening technique for compounds. The method and results provide us a new idea for identification and prioritization of DBPs.

  14. Preparation of mono-radioiodinated tracers for study of the in vivo metabolism of atrial natriuretic peptide in humans

    Energy Technology Data Exchange (ETDEWEB)

    Clerico, A. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Iervasi, G. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Manfredi, C. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Salvadori, S. [Dept. of Pharmaceutical Sciences, Univ. of Ferrara (Italy); Marastoni, M. [Dept. of Pharmaceutical Sciences, Univ. of Ferrara (Italy); Del Chicca, M.G. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Giannessi, D. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Del Ry, S. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Andreassi, M.G. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Sabatino, L. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Iascone, M.R. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Biagini, A. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica; Donato, L. [Consiglio Nazionale delle Ricerche, Pisa (Italy). Lab. di Fisiologia Clinica

    1995-09-01

    The authors evaluate the optimum chemical conditions for labelling atrial natriuretic peptide (ANP) and its metabolites and for preparing highly purified radiotracers which can be used for in vivo kinetic studies of ANP in humans. Synthetic {alpha} h{sub 1-28}ANP and some hormone metabolites were iodinated with Na{sup 125}I or Na{sup 131}I by means of the lactoperoxidase (ANP) or the chloramine-T (ANP metabolites) technique. The biological activity of labelled ANP was tested by means of a binding study using mouse cardiac membranes. A high-performance liquid chromatography (HPLC) procedure was used to purify the labelled hormone and the principal labelled metabolites in venous plasma samples collected up to 50 min after the injection of {sup 125}I-labelled ANP from nine healthy men. The main ANP kinetic parameters were derived from the disappearance curves of the [{sup 125}I]ANP, which were satisfactorily fitted by a bi-exponential function in all subjects. The main advantages of this tracer technique are high accuracy, allowing the identification of the metabolites produced in vivo under steady-state conditions after injection of the precursor (labelled hormone) high sensitivity, allowing the detection of minimal quantities of metabolites high specificity, allowing the detection of possible in vitro artefactual generation of cleavage products of ANP using an internal labelled standard. Utilizing this tracer method, it was possible to estimate the principal parameters of ANP kinetics and also to plot the appearance curves of the labelled metabolites produced in vivo after the injection of the labelled precursor. (orig.). With 5 figs.

  15. Biodistribution and tumor uptake of C60(OH) x in mice

    Science.gov (United States)

    Ji, Zhi Qiang; Sun, Hongfang; Wang, Haifang; Xie, Qunying; Liu, Yuangfang; Wang, Zheng

    2006-02-01

    Radiolabeling of fullerol, 125I-C60(OH) x , was performed by the traditional chloramine-T method. The C-I covalent bond in I-C60(OH) x was characterized by X-ray photoelectron spectroscopy (XPS) that was sufficiently stable for in vivo study. Laser light scattering spectroscopy clearly showed that C60(OH) x aggregated to large nanoparticle clumps with a wide range of distribution. The clumps formed were also visualized by transmission electron microscope (TEM). We examined the biodistribution and tumor uptake of C60(OH) x in five mouse bearing tumor models, including mouse H22 hepatocarcinoma, human lung giantcellcarcinoma PD, human colon cancer HCT-8, human gastric cancer MGC803, and human OS732 osteosarcoma. The accumulation ratios of 125I-C60(OH) x in mouse H22 hepatocarcinoma to that in normal muscle tissue (T/N) and blood (T/B) at 1, 6, 24 and 72 h, reveal that 125I-C60(OH) x gradually accumulates in H22 tumor, and retains for a quite long period (e.g., T/N 3.41, T/B 3.94 at 24 h). For the other four tumor models, the T/N ratio at 24 h ranges within 1.21-6.26, while the T/B ratio ranges between 1.23 and 4.73. The accumulation of C60(OH) x in tumor is mostly due to the enhanced permeability and retention effect (EPR) and the phagocytosis of mononuclear phagocytes. Hence, C60(OH) x might serve as a photosensitizer in the photodynamic therapy of some kinds of tumor.

  16. Biodistribution and tumor uptake of C{sub 60}(OH){sub x} in mice

    Energy Technology Data Exchange (ETDEWEB)

    Ji Zhiqiang; Sun Hongfang, E-mail: shf@pku.edu.cn; Wang Haifang; Xie Qunying; Liu Yuangfang [Peking University, Department of Chemical Biology, College of Chemistry and Molecular Engineering (China); Wang Zheng [Chinese Academy of Medical Sciences, Cancer Institute (China)

    2006-02-15

    Radiolabeling of fullerol, {sup 125}I-C{sub 60}(OH){sub x}, was performed by the traditional chloramine-T method. The C-I covalent bond in I-C{sub 60}(OH){sub x} was characterized by X-ray photoelectron spectroscopy (XPS) that was sufficiently stable for in vivo study. Laser light scattering spectroscopy clearly showed that C{sub 60}(OH){sub x} aggregated to large nanoparticle clumps with a wide range of distribution. The clumps formed were also visualized by transmission electron microscope (TEM). We examined the biodistribution and tumor uptake of C{sub 60}(OH){sub x} in five mouse bearing tumor models, including mouse H22 hepatocarcinoma, human lung giantcellcarcinoma PD, human colon cancer HCT-8, human gastric cancer MGC803, and human OS732 osteosarcoma. The accumulation ratios of {sup 125}I-C{sub 60}(OH){sub x} in mouse H22 hepatocarcinoma to that in normal muscle tissue (T/N) and blood (T/B) at 1, 6, 24 and 72 h, reveal that {sup 125}I-C{sub 60}(OH){sub x} gradually accumulates in H22 tumor, and retains for a quite long period (e.g., T/N 3.41, T/B 3.94 at 24 h). For the other four tumor models, the T/N ratio at 24 h ranges within 1.21-6.26, while the T/B ratio ranges between 1.23 and 4.73. The accumulation of C{sub 60}(OH){sub x} in tumor is mostly due to the enhanced permeability and retention effect (EPR) and the phagocytosis of mononuclear phagocytes. Hence, C{sub 60}(OH){sub x} might serve as a photosensitizer in the photodynamic therapy of some kinds of tumor.

  17. Photolytic removal of DBPs by medium pressure UV in swimming pool water

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Kamilla M.S. [Department of Environmental Engineering, Technical University of Denmark (Denmark); Zortea, Raissa [Department of Land, Environment and Geotechnology Engineering, Polytechnic University of Turin (Italy); Piketty, Aurelia [Institute of Chemistry, Industrial and Chemical Engineering and Technology (INP-ENCIACET), National Polytechnic Institute of Toulouse (France); Vega, Sergio Rodriguez [Chemical Engineering, Complutense University of Madrid (Spain); Andersen, Henrik Rasmus, E-mail: Henrik@ndersen.net [Department of Environmental Engineering, Technical University of Denmark (Denmark)

    2013-01-15

    Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020 min{sup −1} for chloroform to 0.523 min{sup −1} for trichloronitromethane. The rate constants generally increased with bromine substitution. Using the UV removal of combined chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34 kWh m{sup −3} d{sup −1} and the UV dose required to removed 90% of trichloronitromethane was 0.4 kWh m{sup −3} d{sup −1}, while 2.6 kWh m{sup −3} d{sup −1} was required for chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes ranged from 0.6 to 3.1 kWh m{sup −3} d{sup −1}. It was predicted thus that a beneficial side-effect of applying UV for removing combined chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes. - Highlights: ► UV irradiation is able to degrade all 12 investigated disinfection by-products. ► Bromine species are easier to remove than their chlorinated analogues. ► UV dose used for combined chlorine was comparable with doses required for DBP removal. ► Significant removal of some disinfection by-products in swimming pools is indicated.

  18. [A sensitive and specific radioimmunoassay for arginine vasopressin and its validation].

    Science.gov (United States)

    Oki, Y; Ohgo, S; Yoshimi, T

    1984-03-20

    A sensitive and specific radioimmunoassay (RIA) for arginine vasopressin (AVP) has been developed and validated. Synthetic AVP was coupled to bovine serum albumin (BSA) with glutaraldehyde. Antisera against AVP were raised in three rabbits immunized with AVP-BSA complex. After 6 months, at the 16th injection, one of the antisera had a titer high enough to be utilizable for RIA at a final dilution of 1:400,000. The labeling of AVP with 125I Na was performed with the modified chloramine T method, and the purification of iodinated AVP was done with gel filtration chromatography on a Sephadex G-25 fine column (1 X 20 cm) with an elution buffer of 0.01 M acetic acid containing 0.1% BSA. Radioactivities from the Sephadex G-25 were eluted in three peaks. 125I-AVP, which was reactive to the antiserum, was contained in the third peak, and 125I-AVP in the fractions on the down slope of the peak was used for the radioligand in the amount of 1000 cpm. The specific activity of purified 125I-AVP was about 400 muCi/microgram. Diluted antiserum and samples, unlabeled AVP or related peptides were preincubated at 4 degrees C for 24 hr, and then 125I-AVP was added to the mixture and incubated for a further 72 hr. Separation of B and F was done with polyethyleneglycol. The minimal detection limit of AVP, which was 95% of the confidence limit of the mean value of B0, was 0.4 pg/tube. The cross-reactivities with lysine vasopressin, arginine vasotocin, DDAVP and oxytocin were 0.1%, 30%, 1% and 0%, respectively. AVP in plasma was extracted with cold acetone and petroleum ether. The recoveries of synthetic AVP from plasma which was added (2-16 pg) were more than 94%. The intra and inter-assay coefficients of variation determined by plasma of AVP concentration of about 4.8 pg/ml were 8.7% and 11.3%, respectively. The RIA detected AVP of concentration as low as 1 pg/ml following the extraction procedure. AVP immunoreactivity was detected without extraction in urine, and the lyophilized

  19. Spectroscopic analysis of the impact of oxidative stress on the structure of human serum albumin (HSA) in terms of its binding properties

    Science.gov (United States)

    Maciążek-Jurczyk, M.; Sułkowska, A.

    2015-02-01

    Oxygen metabolism has an important role in the pathogenesis of rheumatoid arthritis (RA). Reactive oxygen species (ROS) are produced in the course of cellular oxidative phosphorylation and by activated phagocytic cells during oxidative bursts, exceed the physiological buffering capacity and result in oxidative stress. ROS result in oxidation of serum albumin, which causes a number of structural changes in the spatial structure, may influence the binding and cause significant drug interactions, particularly in polytherapy. During the oxidation modification of amino acid residues, particularly cysteine and methionine may occur. The aim of the study was to investigate the influence of oxidative stress on human serum albumin (HSA) structure and evaluate of possible alterations in the binding of the drug to oxidized human serum albumin (oHSA). HSA was oxidized by a chloramine-T (CT). CT reacts rapidly with sulfhydryl groups and at pH 7.4 the reaction was monitored by spectroscopic techniques. Modification of free thiol group in the Cys residue in HSA was quantitatively determined by the use of Ellman's reagent. Changes of albumin conformation were examined by comparison of modified (oHSA) and nonmodified human serum albumin (HSA) absorption spectra, emission spectra, red-edge shift (REES) and synchronous spectroscopy. Studies of absorption spectra indicated that changes in the value of absorbance associated with spectral changes in the region of 200-250 nm involve structural alterations in peptide backbone conformation. Synchronous fluorescence spectroscopy technique confirmed changes of position of tryptophanyl and tyrosyl residues fluorescent band caused by CT. Moreover analysis of REES effect allowed to observe structural changes caused by CT in the region of the hydrophobic pocket containing the tryptophanyl residue. Effect of oxidative stress on binding of anti-rheumatic drugs, sulfasalazine (SSZ) and sulindac (SLD) in the high and low affinity binding sites was

  20. Functional expression of a single-chain antibody to ErbB-2 in plants and cell-free systems

    Directory of Open Access Journals (Sweden)

    Benevolo Maria

    2006-09-01

    Full Text Available Abstract Background Aberrant signaling by ErbB-2 (HER 2, Neu, a member of the human Epidermal Growth Factor (EGF receptor family, is associated with an aggressive clinical behaviour of carcinomas, particularly breast tumors. Antibodies targeting the ErbB-2 pathway are a preferred therapeutic option for patients with advanced breast cancer, but a worldwide deficit in the manufacturing capacities of mammalian cell bioreactors is foreseen. Methods Herein, we describe a multi-platform approach for the production of recombinant Single chain Fragments of antibody variable regions (ScFvs to ErbB-2 that involves their functional expression in (a bacteria, (b transient as well as stable transgenic tobacco plants, and (c a newly developed cell-free transcription-translation system. Results An ScFv (ScFv800E6 was selected by cloning immunoglobulin sequences from murine hybridomas, and was expressed and fully functional in all the expression platforms, thereby representing the first ScFv to ErbB-2 produced in hosts other than bacteria and yeast. ScFv800E6 was optimized with respect to redox synthesis conditions. Different tags were introduced flanking the ScFv800E6 backbone, with and without spacer arms, including a novel Strep II tag that outperforms conventional streptavidin-based detection systems. ScFv800E6 was resistant to standard chemical radiolabeling procedures (i.e. Chloramine T, displayed a binding ability extremely similar to that of the parental monovalent Fab' fragment, as well as a flow cytometry performance and an equilibrium binding affinity (Ka approximately 2 × 108 M-1 only slightly lower than those of the parental bivalent antibody, suggesting that its binding site is conserved as compared to that of the parental antibody molecule. ScFv800E6 was found to be compatible with routine reagents for immunohistochemical staining. Conclusion ScFv800E6 is a useful reagent for in vitro biochemical and immunodiagnostic applications in oncology

  1. Novel antimicrobial textiles

    Science.gov (United States)

    Cho, Unchin

    2003-10-01

    Many microorganisms can survive, and perhaps proliferate on textiles, generating adverse effects such as: disease transmission, odor generation, pH changes, staining, discoloration and loss of performance. These adverse effects may threaten users' health, deteriorate textile properties and degrade service quality. It may, therefore, be desirable to incorporate antimicrobials on textiles for controlling the growth of microorganisms. This dissertation focuses on the development of antimicrobial fibers and fabrics by integration of antimicrobials with these textiles. The applications of hydantoin-based halamines were mainly investigated in the research. The typical process is that hydantoin containing compounds are grafted onto textiles and transformed to halamine by chlorination. Hydantoin-based halamines are usually chloramines that release chlorine (Cl+) via cleavage of the -NCl functional group which attacks and kills microbes. The antimicrobial behavior is rechargeable many times by rinsing the fiber or fabric with chlorine-containing solution. Some quaternary ammonium type antimicrobials were also investigated in this research. The choice of integrating techniques is dependant on both the textile and antimicrobial compounds. In this dissertation, the nine approaches were studied for incorporating antimicrobial with various textiles: (1) co-extrusion of fibers with halamine precursor additive; (2) grafting of the quaternary ammonium compounds onto ethylene-co-acrylic acid fiber for creating quaternary ammonium type antimicrobial fiber; (3) entrapment of the additives in thermally bonded bicomponent nonwoven fabrics; (4) attaching antimicrobial additives to surfaces with latex adhesive coating; (5) grafting of antimicrobial compounds onto rubber latex via UV exposure; (6) reaction of halamine with needle-punched melamine formaldehyde nonwoven fabric and laminates; (7) coating melamine resin onto tent fabrics and laminates; (8) synthesis of super absorbent polymer

  2. Kinetics and mechanisms of degradation of chloroacetonitriles by the UV/H2O2 process.

    Science.gov (United States)

    Ling, Li; Sun, Jianliang; Fang, Jingyun; Shang, Chii

    2016-08-01

    Haloacetonitriles (HANs) are emerging disinfection by-products (DBPs) that are more toxic than the regulated DBPs and widely found in the chlorinated/chloraminated water. This paper studied kinetics and mechanisms of the degradation of chloroacetonitriles (CANs) by the UV/H2O2 process at pH 6 and 7.5 and H2O2 concentrations of 1 × 10(-3) M, 5 × 10(-3) M and 1 × 10(-2) M. The degradation followed pseudo first-order degradation kinetics. The degradation rate of monochloroacetonitrile (MCAN) remained similar, while those of dichloroacetonitrile (DCAN) and trichloroacetonitrile (TCAN) increased with increasing pH and H2O2 concentrations. The different trends were attributed to the changing contributions of the two major mechanisms: the nucleophilic attack by hydroperoxide ions ( [Formula: see text] ) and the hydroxyl radical (•OH) oxidation. The second-order rate constants of [Formula: see text] towards MCAN, DCAN and TCAN were determined to be 11.8 (±0.62), 4.83 (±0.01) × 10(3), and 2.54 (±0.23) × 10(5) M(-1) s(-1), respectively, while that of •OH were 8.7 × 10(6), 4.4 × 10(6), and degradation of TCAN was mainly attributed to the [Formula: see text] nucleophilic attack, while that of MCAN was dominated by the •OH oxidation. DCAN was degraded by both mechanisms. The nucleophilic attack increased linearly with increasing [Formula: see text] concentration as a result of increasing H2O2 concentration and/or pH, while the •OH oxidation was less dependent on H2O2 concentrations and/or pH. The nucleophilic attack mainly transformed HANs to haloacetamides, while the •OH oxidation dechlorinated HANs. This paper firstly illustrated the importance of the [Formula: see text] nucleophilic attack, in addition to the •OH oxidation, on the CAN degradation in the UV/H2O2 process.

  3. Research on variation of water quality chemical stability during the water treatment process%水质化学稳定性沿工艺流程变化研究

    Institute of Scientific and Technical Information of China (English)

    张庆; 梅红

    2012-01-01

    通过研究水质化学稳定性随水处理工艺流程的变化,探讨影响水质化学稳定性的因素.结果表明:水处理中碱度消耗工艺(混凝、生物活性炭和臭氧氧化工艺)均使水质化学稳定性下降.生物活性炭滤池运行初期生物膜未形成或尚不成熟时,对水质化学稳定性基本无影响,相反,初期活性炭表面金属溶出还可能改善水质化学稳定性.氯胺消毒基本不影响水质化学稳定性,投加NaClO可提高水质化学稳定性.混凝剂投加后增加水中无机阴离子(SO42-和Cl-),增加水体对管道的腐蚀倾向.%Through studying the variation of water quality chemical stability during the water treatment process, the factors influencing the water quality chemical stability were discussed. The results showed that: alkalinity consumption processes (coagulation, biological activated carbon and ozone oxidation) deteriorated the water quality chemical stability. There was almost no influence on water quality chemical stability when biofilm was not formed or not yet mature in the early operation period of biological activated carbon filter. On the contrary, the metal precipitation on the surface of the activated carbon happened in the initial stage might improve the water quality chemical stability. The water quality chemical stability was almost not influenced by chloramines disinfection, but was improved by adding NaClO. As coagulant dosing increased the concentration of the dissolved inorganic anions (SO24- and Cl-), the corrosion tendency of the iron pipe was also aggravated.

  4. Water quality assessment using the AREc32 reporter gene assay indicative of the oxidative stress response pathway.

    Science.gov (United States)

    Escher, Beate I; Dutt, Mriga; Maylin, Erin; Tang, Janet Y M; Toze, Simon; Wolf, C Roland; Lang, Matti

    2012-11-01

    The reporter gene assay AREc32 is based on the induction of the Nrf2 mediated oxidative stress response pathway in the human breast cancer cell line MCF7, where eight copies of the antioxidant response element (ARE) are linked to a reporter gene encoding for luciferase. The Nrf2-ARE pathway is responsive to many chemicals that cause oxidative stress, among them a large number of pesticides and skin irritants. We adopted and validated the AREc32 bioassay for water quality testing. tert-Butylhydroquinone served as the positive control, phenol as the negative control and other reactive chemicals were assessed for their specificity. An environmentally relevant reference chemical, benzo(a)pyrene was the most potent inducer of all tested chemicals. The concentration causing an induction ratio (IR) of 1.5 (EC(IR1.5)) was chosen as the effect benchmark value. The assay was applied to 21 water samples ranging from sewage to drinking water, including secondary treatment and various tertiary treatment options (ozonation, biologically activated carbon filtration, membrane filtration, reverse osmosis, advanced oxidation, chlorination, chloramination). The samples were enriched by solid phase extraction. In most samples the oxidative stress response was far more sensitive than cytotoxicity. The primary and secondary treated effluent exceeded the effect threshold IR 1.5 at a relative enrichment factor (REF) of 1, i.e., the native samples were active. All tertiary treated samples were less potent and their EC(IR1.5) lay between REF 1 and 10. The Nrf2 pathway was induced at a REF of approximately 10 for surface waters and drinking water, and above this enrichment cytotoxicity took over in most samples and quenched the induction. The blank (ultrapure water run through the sample enrichment process) was cytotoxic at an REF of 100, which is the limit of concentrations range that can be evaluated. Treatment typically decreased both the cytotoxicity and oxidative stress response apart

  5. Distribution of 131I-labeled Bothrops erythromelas venom in mice

    Directory of Open Access Journals (Sweden)

    C.M.L. Vasconcelos

    1998-03-01

    Full Text Available Bothrops erythromelas is responsible for many snake bites in northeastern Brazil. In the present study we determined the in vivo distribution of the venom following its subcutaneous injection into mice. B. erythromelas venom and albumin were labeled individually with 131I by the chloramine T method, and separated in a Sephacryl® S-200 column. The efficiency of labeling was 68%. Male Swiss mice (40-45 g, which had been provided with drinking water containing 0.05% KI over a period of 10 days prior to the experiment, were inoculated dorsally (sc with 0.3 ml (2.35 x 105 cpm/mouse of 131I-venom (N = 42, 131I-albumin or 131I (controls, N = 28 each. Thirty minutes and 1, 3, 6, 12, 18 and 24 h after inoculation, the animals were perfused with 0.85% NaCl and skin and various organs were collected in order to determine radioactivity content. There was a high rate of venom absorption in the skin (51% within the first 30 min compared to albumin (20.1% and free iodine (8.2%. Up to the third hour after injection there was a tendency for venom and albumin to concentrate in the stomach (3rd h, small intestine (3rd h and large intestine (6th h. Both control groups had more radioactivity in the digestive tract, especially in the stomach, but these levels decreased essentially to baseline by 12-18 h postinjection. In the kidneys, the distribution profiles of venom, albumin and iodine were similar. Counts at 30 min postinjection were low in all three groups (1.37, 1.86 and 0.77, respectively, and diminished to essentially 0% by 12-18 h. Albumin tended to concentrate in muscle until the 3rd h postinjection (1.98%. There was a low binding of labeled venom in the liver (<0.54%, thyroid (<0.11% and lungs (<0.08%, and no iodinated venom was detected in brain, heart, diaphragm, spleen or bladder. The low venom binding observed in most internal organs, comparable to that of albumin, suggests that B. erythromelas venom does not specifically target most internal organs

  6. Research on Formation Characteristics of Nitrification in Water Distribution System%给水管网中硝化作用的形成特性研究

    Institute of Scientific and Technical Information of China (English)

    赵乐乐; 李星; 杨艳玲; 黄静; 陈伟雄

    2011-01-01

    采用4台BAR反应器串联对氯胺消毒管网中硝化作用的形成特性进行研究,并与实际管网中的水质变化加以比较.测定显示,BAR4中首先出现氨氧化菌(AOB)生长、氨氮降解和硝酸盐氮浓度升高现象;当AOB数量稳定后,模拟管网中的氨氮浓度沿程降低,生物膜及悬浮态AOB数量、亚硝酸盐氮浓度沿程升高到一定值后降低.发生严重硝化的实际管网末梢pH值较出厂水的降低了0.7,出厂水余氯(3.0 mg/L)已不能控制管网中的硝化作用.由于受AOB检测手段的限制,应综合考虑氨氮、余氯、pH值及不同管网点亚硝酸盐氮浓度的变化来判断管网中是否发生了硝化现象.研究表明,4台BAR反应器串联可以模拟发生硝化作用的实际管网中水质的变化.%The formation characteristics of nitrification in water distribution system disinfected with chloramine were investigated using four biofilm annular reactors (BAR) in series, which was compared with the practical water distribution system. A decrease in ammonia and an increase in nitrate first occur in BAR4 at the growth stage of AOB. Ammonia is decreased, AOB in biofilm and bulk and nitrite firstly reach a peak then decline along the pipeline when AOB enter a stationary period. The pH can lower 0.7 from water treatment plant to the end of the water distribution system, while maintaining 3.0 mg/L of residual chlorine in finished water can not suppress the nitrification. Because the AOB method is limited,water quality parameters, such as total residual chlorine, pH, ammonia and nitrite in different points of the system should be simultaneously analyzed to predict the potential of nitrification. The four BAR in series can simulate the variation of water quality in the practical water distribution system with nitrification.

  7. Immunoassay of taxol using anti-taxol antibody and radiolabeled taxol

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T. S.; Hong, J. P.; Kim, H. S.; Awh, O. D.; Choi, C. W.; Lim, S. M. [College of Medicine, Yonsei Univ., Wonju (Korea, Republic of)

    2000-07-01

    Taxol (Paclitaxel), an antineoplastic agent, has been used for treatment of ovarian and breast cancer. Prompt analysis of taxol concentration in the human serum is beneficial to maintain an appropriate taxol concentration in blood, which will enhance therapeutic effect of the drug. This study was aimed to establish a radioimmunoassay system for monitoring the taxol level in blood during cancer treatment. Hemisuccinyltaxol (HT) was synthesized by esterification of taxol with succinic anhydride. Tyraminehemisuccinyltaxol (THT) was synthesized by amide bond formation of the hemisuccinyltaxol with tyramine in the presence of isobutylchloroformate. The synthesized THT was purified by HPLC, Tyraminehemisuccinyltaxol was dissolved in 80% acetonitrile solution, which was stored at 4 .deg. C or 37 .deg. C for 7 days. The stability of tyraminehemisuccinyltaxol was monitored during the storage period. Tyramine-hemisuccinyltaxol was labeled with {sup 125}I (3.7 x 10{sup 7} Bq) by Chloramine-T. The radiolabeled product, ({sup 125}I)iodo-tyraminehemiscuccinyltasol, was allowed to stand at 4 .deg. C or 37 .deg. C for up to 7 days to estimate its stability. The radiochemical purity of ({sup 125}I) iodotyramine-hemisuccinyltaxol was determined by HPLC. In other hand, the titer of taxol monoclonal antibody (3G5A7) was determined by radioimmunoassay using ({sup 125}I) iodotyramine-hemisuccinyltaxol as a radiolabeled antigen. A standard dose response curve was plotted by taxolcompetitive radioimmunoassay. Hemisuccinyltaxol was synthesized with 79.9% yield. Tyraminehemisuccinyltaxol was synthesized with 19.5% yield and purified by HPLC. the chemical purity of Tyraminehemisuccinyltaxol was maintained at 96.5% and 97.5% after 7 days storage at 4 .deg. C and 37.deg. C respectively. The radiochemical purity of ({sup 125}I) iodotyramine-hemisuccinyltaxol was diminished to 88.1% and 86.2% after 7 days storage at 4 .deg. C and 37. deg.C, respectively. The antibody titer against taxol was 1

  8. Preparation of {sup 125}I-iodotyraminehemisuccinyltaxol ({sup 125}ITHT) for competitive taxol radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae Sup; Awh, Ok Doo; Choi, Tae Hyun; Kim, Hyun Suk; Hong, Jun Pyo; Lee, Eun Sook [College of Medicine, Yonsei Univ., Wonju (Korea, Republic of); Choi, Chang Woon; Lim, Sang Moo [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    2002-04-01

    Taxol(Paclitaxel), an antineoplastic agent, has been used in the treatment of ovarian and breast cancers. The determination of optimal Taxol concentrations in human serum was required for enhancing therapeutic effect and maintaining the appropriate Taxol level in blood. This study was aimed to synthesize radiolabeled Taxol derivatives as radiotracer in competitive radioimmuoassay for monitoring Taxol concentrations in blood and to determine the usefulness of its derivatives. Hemisuccinyltaxol(HT) was synthesized by esterification of Taxol with succinic anhydride. Tyraminehemisuccinyltaxol (THT) was synthesized by coupling of HT with tyramine using isobutylchloroformate as coupling agent and purified by HPLC. By using chloramine-T(5.25 mg/ml, 10 {mu}l) as oxidant agent, THT (4 mg/ml, 30 {mu}l) was labeled with {sup 125}I (37 MBq, 1 mCi). To estimate the stability of purified THT, {sup 125}I-iodotyraminehemisuccinyltaxol ({sup 125}ITHT) was dissolved in 80% acetonitrile aqueous solution, and the solution was incubated at 4 .deg. C and 37 .deg. C for 7 days. At various time intervals, the stability of THT and {sup 125}ITHT was monitored. The titer of Taxol monoclonal antibody, 3G5A7, was determined by competitive radioimmunoassay using {sup 125}ITHT as a labeled antigen. A standard dose-response curve was demonstrated by Taxol competitive radioimmunoassay. HT and THT were synthesized with 79.9% and 19.5% yield, respectively. The labeling yield of {sup 125}ITHT was 93%. After 7 days, the chemical purity of THT was 96.5% at 4 .deg. C, and 97.5% at 37 .deg. C. After 3 days, {sup 125}ITHT was stable with 94.7% at 4 .deg. C and 93.4% at 37 .deg. C. After 7 days radiochemical purity was diminished to 88.1% at 4 .deg. C and 86.1% at 37 .deg. C. The titer of Taxol monoclonal antibody, 3G5A7, was determined to 1:256. A standard dose-response cure demonstrated good collinearity (R{sup 2}=0.971) as Taxol concentration-dependent manner. Competitive radioimmunoassay using {sup 125

  9. Electrodegradation of the Acid Green 28 dye using Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes.

    Science.gov (United States)

    Irikura, Kallyni; Bocchi, Nerilso; Rocha-Filho, Romeu C; Biaggio, Sonia R; Iniesta, Jesús; Montiel, Vicente

    2016-12-01

    The statistical Response Surface Methodology (RSM) is applied to investigate the effect of different parameters (current density, j, NaCl concentration, [NaCl], pH, and temperature, θ) and their interactions on the electrochemical degradation of the Acid Green (AG) 28 dye using a Ti/β-PbO2 or Ti-Pt/β-PbO2 anode in a filter-press reactor. LC/MS is employed to identify intermediate compounds. For both anodes, the best experimental conditions are j = 50 mA cm(-2), [NaCl] = 1.5 g L(-1), pH = 5, and θ = 25 °C. After 3 h of electrolysis, a dye solution treated under these conditions presents the following parameters: electric charge per unit volume of the electrolyzed solution required for 90% decolorization (Q(90)) of 0.34-0.37 A h L(-1), %COD removal of ∼100%, specific energy consumption of 18-20 kW h m(-3), and %TOC removal of 32-33%. No loss of the β-PbO2 film is observed during all the experiments. The β-PbO2 films present excellent stability for solutions with pH ≥ 5 ([Pb(2+)] < 0.5 mg L(-1)). Chloroform is the only volatile organic halo compound present in the treated solution under those optimized conditions. Hydroxylated anthraquinone derivatives, aromatic chloramines, and naphthoquinones are formed during the electrolyses. The Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes show significantly better performance than a commercial DSA anode for the electrochemical degradation of the AG 28 dye. The Ti/β-PbO2 anode, prepared as described in this work, is an excellent option for the treatment of textile effluents because of its low cost of fabrication and good performance.

  10. Biochemical and pharmacological studies of native and irradiated crotamine with gamma radiation of {sup 60}Co; Estudo bioquimico e farmacologico das crotaminas nativa e irradiada com radiacao gama de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Mitake, Malvina Boni

    2000-07-01

    Ionizing radiation can change the molecular structure and affect the biological properties of biomolecules. This has been employed to attenuate animal toxins. Crotamine is a strongly basic polypeptide from the South American rattlesnake venom, composed of 42 amino acid residues. It induces skeletal muscle spasms leading to a spastic paralysis of hind limbs in mice. The objective of this thesis was carry out biochemical and pharmacological studies of native and irradiated crotamine with {sup 60} Co. Crotamine was purified from Crotalus durissus terrificus venom by Sephadex G-100 gel filtration followed by ion exchange chromatography, using a Fast Performance Liquid Chromatography (FPLC) system. It was irradiated at 2 mg/ml in 0.15 M Na Cl with 2.0 kGy gamma radiation emitted by a {sup 60} Co source. The native and irradiated crotamine were evaluated by biochemical characterization, toxic activity (LD{sub 50} and biodistribution. The native and irradiated crotamine were labelled with 29.6 MBq of {sup 125} I using chloramine T method, and separated in a Sephadex G-50 column. Male Swiss mice (35{+-} 5 g), were injected i.p. with o.1 mL (2.4 x 10{sup 6} cpm/mouse) of {sup 125} I native crotamine or with 0.4 mL (1.3 x 10{sup 6} cpm/mouse) of {sup 125} I irradiated crotamine. At 0.08; 0.25; 0.5; 1; 2; 4; 8; 12 and 24 hours the animal were killed by ether inhalation. Blood, spleen, liver, kidneys, brain, lungs, heart, and skeletal muscle were collected in order to determine radioactivity content. The results showed that gamma radiation did not change the protein concentration, the electroforetic profile or the primary structure of the protein, although differences were shown by spectroscopic techniques. The gamma radiation diminished the toxicity of crotamine, but it did not abolish bioactivity. Biodistribution studies showed that native and irradiated crotamine have hepatic metabolism and renal elimination. The native and irradiated crotamine have affinity by skeletal

  11. Development of a new radioimmunoassay for erythropoietin using recombinant erythropoietin

    Energy Technology Data Exchange (ETDEWEB)

    Mason-Garcia, M.; Beckman, B.S.; Brookins, J.W.; Powell, J.S.; Lanham, W.; Blaisdell, S.; Keay, L.; Li, S.C.; Fisher, J.W. (Tulane Univ. School of Medicine, New Orleans, LA (USA))

    1990-11-01

    The development of a 24 hour radioimmunoassay for erythropoietin (EPO) using EPO derived from recombinant DNA as both immunogen and ligand is described in the present paper. Mixed breed rabbits immunized with 10 micrograms/kg of EPO derived from a stably transfected cell line (MD) produced antibodies to EPO with high titer (up to 1:896,000 final dilution in the tube), high affinity (8.4 x 10(11) liter/M), and good specificity. Purified EPO from the above source or from AmGen Biologicals (AG) were successfully radioiodinated with the chloramine-T method and used as ligand in the radioimmunoassay. Standard dose-response curves prepared with EPO from both commercial sources were not significantly different and showed a sensitivity of 0.75 to 0.96 mU/tube. The dose-response curves in both systems also showed parallelism with serially diluted serum from a patient with aplastic anemia. Within-assay and between-assay precision were determined by assaying multiple replicates of a serum pool. Recovery of exogenous EPO added to a serum pool averaged 97% for both systems. The range of normal human serum EPO was determined by assaying the sera of 153 hematologically-normal adult subjects and was found to be 1.1 to 27.3 mU/ml for MD EPO and 0.5 to 16.7 mU/ml for AG EPO. Sera from several patients with hematologic abnormalities were also assayed, including those of 36 patients with anemia of end-stage renal disease (mean +/- SEM, 29.5 +/- 4.0 mU/ml; P less than 0.01). In conclusion, this new, more rapid and sensitive radioimmunoassay system can be used to measure EPO levels in sera from normal human subjects and patients with several types of anemia, and should also be very useful in therapeutic drug monitoring of patients receiving EPO from various commercial sources.

  12. Preparation of the radiopharmaceutical {sup 131}I-Anti-CD20 for the treatment of lymphomas; Preparacion del radiofarmaco {sup 131}I-Anti-CD20 para el tratamiento de linfomas

    Energy Technology Data Exchange (ETDEWEB)

    Pantoja H, I.E

    2004-07-01

    At the present time they are considered to the lymphomas like a problem of first magnitude since has happened it is necessary to be the fifth cancer cause in the world. Different treatments focused to the lymphoma like the chemotherapy and the radiotherapy, have been employees to counteract the No-Hodgkin lymphoma, without these they don't exclude the healthy tissue of the toxicity. It is for it that is taking a new direction with the employment of the directed radioimmunotherapy since this it allows to kill wicked cells selectively with radiation dose joined to the apoptosis and cytotoxicity induced by the own one bio molecule. The radioimmunotherapy with radiolabelled antibodies directed to the surface antigen CD20 represents a new modality for the treatment of No-Hodgkin lymphoma and potentially other illnesses. In this work the parameters of optimization are presented for the preparation, control of quality and evaluation of the stability in vitro and in vivo of the monoclonal antibody anti-CD20 labelled with {sup 131} I for the treatment of No-Hodgkin lymphoma. The anti-CD20 labelled by the chloramine-T method with high radiochemical purity (>98%), it is stable in solution for but of a half life of the radionuclide (8.04 days) The {sup 131} I-anti-CD20 doesn't present dehalogenation in vitro (human serum) during 24 h of incubation at 37 C. According to the tests carried out to establish the immunoreactivity, a percentage of union to cells was obtained (B lymphocytes) bigger to 30%. The biodistribution in mice balb/c one hour after their administration, it shows that there is not high reception in mucous neither kidneys, what indicates that the complex is stable in vivo. In conclusion, the radiopharmaceutical {sup 131} I-anti-CD20 was obtained in sterile injectable solution and free of pyrogens with a radiochemical purity bigger to 98% and a specific activity of 296 MBq. The radiolabelled molecule maintains its biological recognition for the receiving

  13. A New Group of Disinfection Byproducts in Drinking Water: Trihalo-hydroxy-cyclopentene-diones.

    Science.gov (United States)

    Pan, Yang; Li, Wenbin; Li, Aimin; Zhou, Qing; Shi, Peng; Wang, Ying

    2016-07-19

    We report the detection, synthesis, preparative isolation, structure characterization and identification, and formation of a new group of drinking water disinfection byproducts (DBPs): trihalo-hydroxy-cyclopentene-diones (trihalo-HCDs). With ultra performance liquid chromatography (UPLC)/electrospray ionization-triple quadruple mass spectrometry analyses (full scans, multiple reaction monitoring, and product ion scans) and high-resolution mass spectrometry analyses (full scans), the new group of DBPs was identified with formulae and proposed with structures. However, due to a lack of commercially available standard compounds, structure identification of this new group of DBPs was challenging. 2,4,6-Trihydroxybenzaldehyde was found to be a good precursor for the synthesis of the tribromo species (m/z 345/347/349/351) in the new group of DBPs by reacting with bromine at a 2,4,6-trihydroxybenzaldehyde-to-bromine molar ratio of 1:8. With UPLC/photodiode array analysis (simultaneous 2- and 3-dimensional operations), the new DBP was determined to have a maximum UV absorption at the wavelength of 280 nm. Through isolation with high performance liquid chromatography/UV-triggered collections followed by lyophilization, the pure standard of the new DBP was obtained. Characterized with Fourier transform infrared spectroscopy, the pure standard of the new DBP was finally identified to be tribromo-HCD, and thus the new group of DBPs was identified to be trihalo-HCDs. On the basis of the disclosed structure, formation pathways of tribromo-HCD through reactions of three different precursors and bromine were proposed and partially verified. Moreover, increasing the bromide level in source water shifted the formation of trihalo-HCDs from being more chlorinated to being more brominated; with an increase in the contact time from 1 h to 5 d, the formation of trihalo-HCDs kept increasing in chloramination, whereas they kept decreasing in chlorination; with an increase in the pH from 6

  14. Distribution of {sup 131} I- labeled Bothrops erythromelas venom in mice

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, C.M.L.; Valenca, R.C.; Araujo, E.A. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia; Modesto, J.C.A.; Pontes, M.M.; Guarnieri, M.C. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Zoologia; Brazil, T.K. [Bahia Univ., Salvador, BA (Brazil). Inst. de Biologia

    1998-03-01

    Bothrops erythromelas is responsible for many snake bites in northeastern Brazil. In the present study we determined the in vivo distribution of the venom following its subcutaneous injection into mice. B. erythromelas venom and albumin were labeled individually with {sup 131} I by the chloramine T method, and separated in a Sephacryl S-200 column. The efficiency of labeling was 68%.Male Swiss mice (40-45 g), which had been provided with drinking water containing 0.05% KI over a period of 10 days prior to the experiment, were inoculated dorsally (sc) with 0.3 ml (2.35 x 10{sup 5} cpm/mouse) of {sup 131} I-venom (N = 42), {sup 131} -albumin or {sup 131} I (controls, N = 28 each). Thirty minutes and 1,3, 6, 12, 18 and 24 h after inoculation, the animals were perfused with 0.85% Na Cl and skin and various organs were collected in order to determine radioactivity content. There was a high rate of venom absorption int he skin (51%) within the first 30 min compared to albumin (20.1%) and free iodine (8.2%). Up to the third hour after injection there was a tendency for venom and albumin to concentrate in the stomach ( 3 rd h),small intestine (3 rd h) and large intestine (6th h). Both control groups had more radioactivity in the digestive tract, especially in the stomach, but these levels decreased essentially to baseline by 12-18 h postinjection. In the kidneys, the distribution profiles of venom, albumin and iodine were similar. Counts at 30 min postinjection were low in all three groups (1.37, 1.86 and 0.77, respectively), and diminished to essentially 0% by 12-18 h. Albumin tended to concentrate in muscle until the 3 rd h postinjection (1.98%).There was a low binding of labeled venom in the liver (B. erythromelas venom does not specifically target most internal organs). That is, the systemic effects of envenomation ar mainly due to an indirect action. (author) 14 refs., 2 figs.

  15. Assembling of ({beta}LPH) beta-lypothrophine radioimmunoassay. Plasma levels standardization in normal individuals and patients with hypophysis and adrenals diseases; Montagem do radioimunoensaio da beta-lipotrofina ({beta}LPH). Padronizacao dos niveis plasmaticos em individuos normais e em pacientes com doencas hipofisarias e adrenais

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Margaret de

    1988-12-31

    The present study investigates the extraction and radioimmunoassay (RIA) conditions of plasma {beta}LPH. It was extracted by the activated silicic acid method, with a mean extraction efficiency of 31.6% and a mean intra-extraction variation coefficient of 8.1%. Radioiodination was performed by the chloramine-T method and {beta}LPH {sup 125} I was purified by gel chromatography on Sephadex G100. Estimated specific activity ranged from 100 to 192.8 {mu}Ci/{mu}g, with a mean incorporation percentage of 66.6%. The titer of the first antibody was 1:50.000/100 {mu}l. The assay was performed under non-equilibrium conditions, with a pre-incubation period of 24 hours and incubation of 4 hours. Mean immunoreactivity (Bo/Total) was 21.1%, with a mean Blank/Total ratio of 2.3%. Sensitivity, expressed as the mean minimum detectable dose, was 40 pg/tube, equivalent to 56 pg/ml plasma. Intra-assay variation coefficients were 6.5%, 3.8% and 6.8%, respectively, at B/Bo levels of 0.8, 0.6 and 0.4 of the standard curve. At B/Bo equal to 0.5, the intra-assay variation coefficient was 20.9%. Replicates of 14 plasma samples showed a correlation coefficient of r 0.99, (p< 0.05). Parallelism between the curve obtained with different volumes of an extract with a high {beta}LPH value and the standard curve was found. The method was controlled biologically by the presence of correlation between the plasma {beta}LPH levels and determined pathological states and with clinical functional studies. Twenty seven normal individuals, 10 patients with Cushing`s disease to a tumor of the hypophysis, 4 patients with Cushing syndrome due to an adrenal tumor, 10 patients Addison disease, and 8 patients with hypopituitarism were studied. (author). 119 refs., 28 figs., 2 tabs.

  16. Advanced oxidation protein products in plasma: stability during storage and correlation with other clinical characteristics.

    Science.gov (United States)

    Matteucci, E; Biasci, E; Giampietro, O

    2001-12-01

    Proteins are susceptible to free radical damage. We measured advanced oxidation protein products (AOPP) in the plasma of 56 hospitalised patients. Concentrations of AOPP were expressed as chloramine-T equivalents by measuring absorbance in acidic conditions at 340 nm in the presence of potassium iodide. We also determined erythrocyte sedimentation rate (ESR), circulating urea, creatinine, glucose, uric acid, electrolytes, lipids, total proteins and fractions and fibrinogen. Twenty-four samples were processed both immediately and after 7, 15, 30, 90, 180 and 438 days of storage at both at -20 degrees C and -80 degrees C (aliquots were frozen and thawed only once) to evaluate AOPP stability. The remaining 32 samples were also processed for thiobarbituric-acid-reactive substances (TBARS). Mean AOPP concentration in all 56 patients was 48.3+/-37.2 microM. Mean basal concentration of AOPP in the 24 plasma samples (55.0+/-47.1 microM) showed no significant change at each intermediate determination, yet significantly increased after 438 days of storage both at -80 degrees C (96.6+/-83.2, p<0.01) and, markedly, at -20 degrees C (171.3+/-94.6, p<0.001). TBARS concentration was 1.59+/-0.65 micromol/l. Multiple regression analysis evidenced that AOPP concentration was positively correlated (multiple r=0.62, p<0.001) with serum urea and triglycerides, but negatively correlated with patient age (indeed, serum albumin and total proteins decreased with increasing age, r=0.3, p<0.05). TBARS concentration was associated with ESR and serum glucose (multiple r=0.73, p<0.001), yet positively with AOPP (r=0.39, simple p<0.05). We conclude that AOPP remain stable during sample storage both at -20 degrees C and -80 degrees C for 6 months. Renal failure and hypertriglyceridemia probably enhance the in vivo process of AOPP formation. Oxidative damage as measured by TBARS may be increased because of exposure to hyperglycemia causing nonenzymatic glycation of plasma proteins.

  17. APPLICATION OF THE COMBINED UV AND CHLORINE DISINFECTION IN WATER PLANT%紫外线和化合氯联合消毒在水厂的应用研究

    Institute of Scientific and Technical Information of China (English)

    潘晓; 王祥勇; 陈洪斌

    2012-01-01

    Based on the pilot and productive ultraviolet disinfection devices in a water plant in the south China, we studied the combined UV and chlorine disinfection effect on biological activated carbon effluent, evaluated the effect of UV disinfection system in the water treatment plant. Studies have shown that the removal rate of biological activated carbon effluent bacteria number could reach 2.6 Ig in 480 J/m2 UV dose condition, but UV have no continuous sterilization. UV disinfection system in water treatment plant generally performed wells, the total number of bacteria from the combined UV and chlorine disinfection system effluent was 0, ultraviolet disinfection efficiency reduced after a long time running. Biological activated carbon process have better control effect on chloramines disinfection by-products, U V disinfection does not increase the chlorine disinfection by-products formation.%以南方某水厂的中试和生产紫外消毒装置为基础,考察了紫外和化合氯联合消毒对生物活性炭出水细菌的杀灭效果,对紫外消毒在该水厂的应用效果进行了评价.研究表明,在480 J/m2的剂量下,生物活性炭出永细菌对数去除率可达2.6 lg,但是紫外无持续杀菌作用,水厂的紫外消毒装置总体效果良好,紫外化合氯消毒后出水细菌总数为0,紫外线消毒长时间运行后灭菌效率有所降低;生物活性炭工艺对氯胺消毒副产物有较好的控制效果,紫外消毒未增加氯消毒副产物的生成量.

  18. Disinfection of model indicator organisms in a drinking water pilot plant by using PEROXONE.

    Science.gov (United States)

    Wolfe, R L; Stewart, M H; Liang, S; McGuire, M J

    1989-09-01

    at an applied ozone dosage of 2.0 mg/liter (and a 4-min contact time) when the H2O2/O3 ratio was less than or equal to 0.5. Comparative disinfection experiments indicated that free chlorine was the most potent bactericidal agent, followed (in descending order of effectiveness) by ozone, PEROXONE, and chloramines. These results indicate that the PEROXONE process must be optimized for each source water to achieve microbicidal effectiveness.

  19. Influence of Organic Nitrogen Compounds on Chlorine Disinfection%有机氮类化合物对氯消毒影响研究

    Institute of Scientific and Technical Information of China (English)

    徐华; 杨艳玲; 王花平; 梁贞淑

    2012-01-01

    受污染饮用水水源中都含多种有机氮类化合物,会对氯消毒效果产生影响.试验采用有机氮类化合物甘氨酸、亮氨酸、赖氨酸、天冬氨酸、半胱氨酸和甲胺,研究了有机氮类化合物浓度和pH值对消毒效果的影响.结果表明,有机氮类化合物都会和自由氯迅速反应生成大量的有机氯胺,使消毒效果显著下降;不同有机氮类化合物对氯消毒效果的影响有很大差异,半胱氨酸的影响最为明显,使得氯几乎丧失消毒能力.因此,对有机氮类化合物的含量和去除应考虑改善氯的投加方式或氯消毒工艺,建立安全有效的消毒方法.%Many organic nitrogen compounds are contained in polluted resource of drinking water, which seriously influence on chlorine disinfection. Typical organic nitrogen compounds including glycine, leucine, lysine, aspartic acid, cysteine, and methylamine were applied. Influences of organic nitrogen compound dosage and pH on disinfection effects are investigated. Results show that many organic chloramines are produced by prompt action of organic nitrogen compounds and free chlorine to decrease disinfection effects pronounced. Influences on chlorine disinfection effects are different through different organic nitrogen compounds. Influence of cysteine is most obvious to cause chlorine losing disinfection capacity. Therefore, contents and removal of organic nitrogen compounds must be attached. The chlorine dosing mode and chlorine disinfection process can be improved and the effective safe disinfection method must be established.

  20. Study on Disinfection and Anti-microbial Technologies for Drinking Water%饮用水的消毒及杀菌技术研究

    Institute of Scientific and Technical Information of China (English)

    朱琨; 伏小勇

    2001-01-01

    饮用水处理消毒过程中可产生一系列致癌物质,主要是氯与水中的有机物和其它化学成分反应的结果,其中典型产物有三氯甲烷.通过对常用消毒剂液氯,臭氧,二氧化氯,高锰酸钾,氯胺及过氧化氢的实验对比,证明二氧化氯是高效,方便,廉价的消毒剂.它不仅对一般病原菌类有明显的抑制和杀菌作用,对清除难以灭杀的潜原性病毒也有理想的效果.在净化水中石油类有机物时,二氧化氯的效果受到反应时间,注入方式和pH值的影响.%Disinfection by-products produced by the reaction betweenchlorine and dissolved organic compounds and other chemicals are considered as a worrying problem in the drinking water treatment process since a series of mutagenic carcinogen substances are formed including trihalomethanes (THMs). Among the tested disinfectants (chlorine, ozone, chlorine dioxide, potassium permanganate, chloramines and hydrogen peroxide etc.), chlorine dioxide has proved to be the most feasible and effective oxidant for drinking water treatment and removal of pathogens due to its oxidation efficiency, low cost and simple way of utilization. A series of experiments indicate that chlorine dioxide can significantly restrain production of trihalomethanes (THMs) and control bacteria growth particularly for Cryptosporidium oocysts.The experiments verified that both ozone and chlorine dioxide are absolutely vital to ensure that any microorganisms arising from fecal contamination of water storage are destroyed. The paper discusses oxidation capacity of chlorine dioxide, especially for removing petroleum compounds, which is affected by reaction time, gas injection way, and pH of treated water.

  1. Oxidation of 3,6-dioxa-1,8-octanedithiol by platinum(IV) anticancer prodrug and model complex: kinetic and mechanistic studies.

    Science.gov (United States)

    Huo, Shuying; Shen, Shigang; Liu, Dongzhi; Shi, Tiesheng

    2012-06-07

    Thioredoxins are small redox proteins and have the active sites of Cys-Xaa-Yaa-Cys; they are overexpressed by many different cancer cells. Cisplatin and Pt(II) analogues could bind to the active sites and inhibit the activities of the proteins, as demonstrated by other researchers. Platinum(IV) anticancer drugs are often regarded as prodrugs, but their interactions with thioredoxins have not been studied. In this work, 3,6-dioxa-1,8-octanedithiol (dithiol) was chosen as a model compound for the active sites of thioredoxins, and its reactions with cis-[Pt(NH(3))(2)Cl(4)] and trans-[PtCl(2)(CN)(4)](2-) (cisplatin prodrug and a model complex) were studied. The pK(a) values for the dithiol were characterized to be 8.7 ± 0.2 and 9.6 ± 0.2 at 25.0 °C and an ionic strength of 1.0 M. The reaction kinetics was followed by a stopped-flow spectrophotometer over a wide pH range. An overall second-order rate law was established, -d[Pt(IV)]/dt = k'[Pt(IV)][dithiol], where k' stands for the observed second-order rate constants. Values of k' increased several orders of magnitude when the solution pH was increased from 3 to 9. A stoichiometry of Δ[Pt(IV)]/Δ[dithiol] = 1:1 derived for the reduction process and product analysis by mass spectrometry indicated that the dithiol was oxidized to form an intramolecular disulfide, coinciding with the nature of thioredoxin proteins. All of the reaction features are rationalized in terms of a reaction mechanism, involving three parallel rate-determining steps depending on the pH of the reaction medium. Rate constants for the rate-determining steps were evaluated. It can be concluded that Pt(IV) anticancer prodrugs can oxidize the reduced thioredoxins, and the oxidation mechanism is similar to those of the oxidations of biologically important reductants by some reactive oxygen species (ROS) such as hypochlorous acid/hypochlorite and chloramines.

  2. Direct electrochemical oxidation of ammonia on graphite as a treatment option for stored source-separated urine.

    Science.gov (United States)

    Zöllig, Hanspeter; Fritzsche, Cristina; Morgenroth, Eberhard; Udert, Kai M

    2015-02-01

    Electrolysis can be a viable technology for ammonia removal from source-separated urine. Compared to biological nitrogen removal, electrolysis is more robust and is highly amenable to automation, which makes it especially attractive for on-site reactors. In electrolytic wastewater treatment, ammonia is usually removed by indirect oxidation through active chlorine which is produced in-situ at elevated anode potentials. However, the evolution of chlorine can lead to the formation of chlorate, perchlorate, chlorinated organic by-products and chloramines that are toxic. This study focuses on using direct ammonia oxidation on graphite at low anode potentials in order to overcome the formation of toxic by-products. With the aid of cyclic voltammetry, we demonstrated that graphite is active for direct ammonia oxidation without concomitant chlorine formation if the anode potential is between 1.1 and 1.6 V vs. SHE (standard hydrogen electrode). A comparison of potentiostatic bulk electrolysis experiments in synthetic stored urine with and without chloride confirmed that ammonia was removed exclusively by continuous direct oxidation. Direct oxidation required high pH values (pH > 9) because free ammonia was the actual reactant. In real stored urine (pH = 9.0), an ammonia removal rate of 2.9 ± 0.3 gN·m(-2)·d(-1) was achieved and the specific energy demand was 42 Wh·gN(-1) at an anode potential of 1.31 V vs. SHE. The measurements of chlorate and perchlorate as well as selected chlorinated organic by-products confirmed that no chlorinated by-products were formed in real urine. Electrode corrosion through graphite exfoliation was prevented and the surface was not poisoned by intermediate oxidation products. We conclude that direct ammonia oxidation on graphite electrodes is a treatment option for source-separated urine with three major advantages: The formation of chlorinated by-products is prevented, less energy is consumed than in indirect ammonia oxidation and

  3. Seasonal evaluation of the presence of 46 disinfection by-products throughout a drinking water treatment plant

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Maria; Montesinos, Isabel; Cardador, M.J.; Silva, Manuel; Gallego, Mercedes, E-mail: mercedes.gallego@uco.es

    2015-06-01

    In this work, we studied a total of 46 regulated and non-regulated disinfection by-products (DBPs) including 10 trihalomethanes (THMs), 13 haloacetic acids (HAAs), 6 halonitromethanes (HNMs), 6 haloacetonitriles (HANs) and 11 aldehydes at different points in a drinking water treatment plant (DWTP) and its distribution network. Determining an increased number of compounds and using accurate, sensitive analytical methodologies for new DBPs can be useful to overcome some challenges encountered in the comprehensive assessment of the quality and safety of drinking water. This paper provides a detailed picture of the spatial and seasonal variability of DBP concentrations from raw water to distribution network. Samples were collected on a monthly basis at seven different points in the four seasons of a year to acquire robust data for DBPs and supplementary quality-related water parameters. Only 5 aldehydes and 2 HAAs were found in raw water. Chlorine dioxide caused the formation of 3 new aldehydes (benzaldehyde included), 5 HAAs and chloroform. The concentrations of DBPs present in raw water were up to 6 times higher in the warmer seasons (spring and summer). The sedimentation process further increased their concentrations and caused the formation of three new ones. Sand filtration substantially removed aldehydes and HAAs (15–50%), but increased the levels of THMs, HNMs and HANs by up to 70%. Chloramination raised the levels of 8 aldehydes and 7 HAAs; also, it caused the formation of monoiodoacetic acid, dibromochloromethane, dichloroiodomethane and bromochloroacetonitrile. Therefore, this treatment increases the levels of existing DBPs and leads to the formation of new ones to a greater extent than does chlorine dioxide. Except for 5 aldehydes, the 23 DBPs encountered at the DWTP exit were found at increased concentrations in the warmer seasons (HAAs by about 50% and THMs by 350%). - Highlights: • Occurrence of 46 regulated and non-regulated DBPs through a DWTP was

  4. Mechanism and Influence Factors of Electrolytic Degradation of Urea by Low-amperage Electric Current%微电流电解对尿素降解的机理及影响因素研究

    Institute of Scientific and Technical Information of China (English)

    林莉; 谢雯静; 赵良元; 冯璁

    2015-01-01

    In this research,urea in swimming pools was treated by low-amperage electric current,and the influence factors including current density and chloride ion concentration and the mechanism of electrolytic removal of urea were investigated.Results indicated that urea was oxidized by active chlorine which was produced when there was high concentration of chloride ion in the solution with ruthenium-titanium as anode material and stainless steel as cathode material.No harmful by-product such as ammonia nitrogen or chloramines was produced.Urea possibly de-graded into gases like N2 and volatilized into the air.Current density and chloride ion concentration have great effect on the efficiency of urea removal.The removal of urea increased with the rise of current density and chloride ion concentration.Urea removal rate reached 99.5%at current density of 12 mA/cm2 and chloride ion concentra-tion of 400 mg/L by 30 min of electrolytic treatment.Due to the high removal rate of urea by electrolysis treatment with no need of electrolyte,electrolytic removal of urea by low-amperage electric current is feasible for the treatment of swimming pool water.%采用微电流电解技术对模拟游泳池水中的尿素进行降解处理,探索了电解对尿素的去除机理,研究了电流密度和氯离子浓度等因素对电解去除尿素效果的影响。结果表明:以钌钛和不锈钢分别做阳极和阴极材料,当水溶液中有较高浓度的氯离子存在时,电解过程中产生的活性氯使得尿素被氧化,尿素降解产物中无氨氮、氯胺等二次污染物,尿素极有可能通过电解生成了N2等气体挥发到空气中。电流密度和氯离子浓度对尿素的去除效率有很大影响,随着电流密度和氯离子浓度的增加,尿素去除效率逐渐上升。在500 mg/L的氯离子浓度条件下,电流密度为12 mA/cm2时,电解处理30 min时尿素去除率可达99.5%。将微电流电解技术应用于游泳池

  5. Research on the Technology of Exterminating the Defacing Organisms Limnoperna Fortunei by Oxidant in Water Delivery Systems%输水系统中污损生物沼蛤的氧化剂灭杀技术研究

    Institute of Scientific and Technical Information of China (English)

    魏小熙; 杨正健; 刘德富; 谭纤茹

    2016-01-01

    近年来,我国南方输水工程常受沼蛤(limnoperna fortunei)生物污损的危害。沼蛤是一种污损性入侵生物,入侵输水工程后聚团附着于输水系统表面可腐蚀附着面、降低管道过流能力、污染水质等。以沼蛤防治为目的研究二氧化氯(ClO2)、氯胺T(C7H7ClNNaO2S·3(H2O))、高锰酸钾(KMnO4)、次氯酸钠(NaClO)和过氧化氢(H2O2)5种水处理常用氧化剂对沼蛤的杀灭效果及足丝溶解特性,以得出基于化学氧化剂的沼蛤防治措施。结果表明:次氯酸钠为5种氧化剂中灭杀沼蛤的最佳试剂,死亡率随次氯酸钠投加浓度增加而增大,但次氯酸钠投加浓度大于20 mg/L时水体中pH等环境条件受到较大影响,依据水体中有效氯衰减规律及灭杀效果,次氯酸钠作为沼蛤杀灭剂初始投加的有效氯浓度宜为10.0~20.0 m g/L。%In recent years ,water project in South China is often affected by the defacing hazards of limnoperna fortunei ,which is a kind of defacement of invasive species .Limnoperna fortunei attaches together to the surface of the water delivery system when they invade the water conveyance project ,which can corrode the adhesion surface ,reduce the capacity of pipeline flow ,pollute the water etc .For the purpose of prevention of limnoperna fortunei ,we study the chlorine dioxide (ClO2 ) ,chloramine-T(C7 H7ClNNaO2S · 3(H2O),potassiumpermanganate(KMnO4),sodiumhypochlorite(NaClO)andhydrogenperoxide(H2O2),thefivekindsofcom‐monly used water treatment oxidant on the elimination effect and byssus dissolution characteristics of limnoperna fortunei ,in order to get its prevention and control measures based on the chemical oxidants .From the experiment we can get the following conclusions . Sodium hypochlorite is the best reagent of the five oxidants to kill limnoperna fortunei ,and with the increase in the initial active chlo‐rine concentration ,the mortality rate of

  6. Understanding, Monitoring, and Controlling Biofilm Growth in Drinking Water Distribution Systems.

    Science.gov (United States)

    Liu, Sanly; Gunawan, Cindy; Barraud, Nicolas; Rice, Scott A; Harry, Elizabeth J; Amal, Rose

    2016-09-06

    feasible with fluorescence microscopy (epifluorescence and CLSM imaging with DNA, RNA, EPS, and protein and lipid stains) and electron microscopy imaging (ESEM). Importantly, thorough identification of microbial fingerprints in drinking water biofilms is achievable with DNA sequencing techniques (the 16S rRNA gene-based identification), which have revealed a prevalence of previously undetected bacterial members. Technologies are now moving toward in situ monitoring of biomass growth in distribution networks, including the development of optical fibers capable of differentiating biomass from chemical deposits. Taken together, management of biofilm growth in water distribution systems requires an integrated approach, starting from the treatment of water prior to entering the networks to the potential implementation of "biofilm-limiting" operational conditions and, finally, ending with the careful selection of available technologies for biofilm monitoring and control. For the latter, conventional practices, including chlorine-chloramine disinfection, flushing of DWDS, nutrient removal, and emerging technologies are discussed with their associated challenges.

  7. SYSTEMATIC EVALUATION ON DISINFECTION EFFECICACY OF DIFFERENT CHLORINE DISINFECTANTS%不同种类含氯消毒剂消毒效果研究的系统评价

    Institute of Scientific and Technical Information of China (English)

    刘真; 张林; 熊鸿燕

    2011-01-01

    Disinfection; 37 English literatures are distributed in 17 journals, and 37.84% are published in Water Research, 13.51% are published in Journal of Hospital Infection.Chlorine, chlorine dioxide, sodium hypochlorite, sodium dichloroisocyanurate, trichloroisocyanuric acid ( TCCA), calcium hypochlorite and chloramine - T are involved in the 102 literatures.The order of comprehensive sterilization effect is as follows (from strong to weak): chlorine dioxide, TCCA, sodium dichloroisocyanurate, sodium hypochlorite.Coclusion Numbers of studies on bactericidal effect of chlorine disinfectants still leap into the front ranks among the studies of chemical disinfectant in the first decade of this century.Chlorine dioxide, sodium hypochlorite, sodium dichloroisocyanurate, and trichloroisocyanuric acid are the most widely used and studied.

  8. Analysis on Sanitary Quality of Hemodialysis Water in Hospitals of Hunan Province During the Period of 2009 - 2011%湖南省2009-2011年医院血液透析用水卫生质量分析

    Institute of Scientific and Technical Information of China (English)

    庞浩; 吴传业; 黄涛; 陈彦华; 胡冀; 杨新文

    2012-01-01

    目的 了解近3年湖南省医院血液透析用水的卫生状况,为血透用水卫生质量的规范化管理提供科学依据.方法 于2009-2011年先后采集湖南省的77家不同等级医院的血液透析用水样品,按照《血液透析用水卫生标准》进行理化指标、微生物指标的检测分析和判定.结果 血透用水中氯化物、钙、氯胺、内毒素和菌落总数等超标率分别为11.7%、2.6%、2.6%、23.4%、1.3%,其他项目均合格.三甲医院和非三甲医院透析用水合格率差异无统计学意义.结论 影响湖南省血液透析用水卫生质量的主要因素是氯化物和内毒素,定期监测、及时更换水处理设备组件、加强输配水管路的清洗消毒等措施是提高血液透析用水水质的关键.%Objective To investigate the sanitary quality of hemodialysis water among hospitals of Hunan Province in the past 3 years, and to provide a scientific basis for the standardized management of hemodialysis water. Methods The samples of hemodialysis water were collected from 77 different levels of hospitals in Hunan Province from 2009 to 2011. Physicochemical and microbial indexes of the samples were measured and judged according to Sanitary Standard for Hemodialysis Water. Results The disqualification rates of chloride, calcium, chloramine, esotoxin and total number of bacterial colony were 11. 7%, 2.6%,2.6%, 23.4%, and 1.3%, respectively. The other inspection items were qualified. But the qualified rates showed no statistically significant difference between 3A grade hospitals and other grades hospitals. Conclusions The main influencing factors for sanitary quality of hemodialysis water in Hunan are chloride and esotoxin. The key measures to improve the quality of hemodialysis water are to monitor regularly, replace water treatment device in time, wash and disinfect the water pipes.

  9. Utilization of N-X bonds in the synthesis of N-heterocycles.

    Science.gov (United States)

    Minakata, Satoshi

    2009-08-18

    Nitrogen-containing heterocycles--such as aziridines, pyrrolidines, piperidines, and oxazolines--frequently show up as substructures in natural products. In addition, some of these species show potent biological activities. Therefore, researchers would like to develop practical and convenient methods for constructing these heterocycles. Among the available methods, the transfer of N(1) units to organic molecules, especially olefins, is a versatile method for the synthesis of N-heterocycles. This Account reviews some of our recent work on the synthesis of N-heterocycles using the N-X bond. A nitrogen-halogen bond bearing an electron-withdrawing group on the nitrogen can be converted to a halonium ion. In the presence of C-C double bonds, these species produce three-membered cyclic halonium intermediates, which can be strong electrophiles and can produce stereocontrolled products. N-Halosuccinimides are representative sources of halonium ions, and the nitrogen of succinimide is rarely used in organic synthesis. If the nitrogen could act as a nucleophile, after releasing halonium ions to C-C double bonds, we expect great advances would be possible in the stereoselective functionalization of olefins. We chose N-chloro-N-sodio-p-toluenesulfonamide (chloramine-T, CT), an inexpensive and commercially available reagent, as our desired reactant. In the presence of a catalytic amount of CuCl or I(2) and AgNO(3), we achieved the direct aziridination of olefins with CT. The reaction catalyzed by I(2) could be carried out in water or silica-water as a green process. The reaction of iodoolefins with CT gave pyrrolidine derivatives under extremely mild conditions with complete stereoselectivity. We also extended the utility of the N-chloro-N-metallo reagent, which is often unstable and difficult to work with. Although CT does not react with electron-deficient olefins without a metal catalyst or an additive, we found that N-chloro-N-sodiocarbamates react with electron

  10. 门静脉灌注胶原酶逆转四氯化碳致实验兔肝硬化%Portal administration of collagenase reverse liver cirrhosis in rabbit CCl4 model

    Institute of Scientific and Technical Information of China (English)

    邱慧彬; 金博; 孙涛; 于晓红; 杨英祥; 付山峰; 路平

    2011-01-01

    目的 观察门静脉灌注胶原酶对逆转兔实验性肝硬化的作用。方法 实验动物分4组,1组:四氯化碳注射12周后行门静脉置管,1周后开始门静脉灌注胶原酶4周;2组:四氯化碳注射12周后行门静脉置管,1周后开始门静脉灌注生理盐水4周;3组:橄榄油注射12周后行门静脉置管,1周后开始门静脉灌注胶原酶4周;4组:橄榄油注射12周后行门静脉置管,1周后开始门静脉灌注生理盐水4周。以上各组取肝组织,用氯胺T法检测门静脉灌注实验前后肝组织的羟脯氨酸含量及肝组织的病理检查。结果 经过的四氯化碳(CCL4)注射和胶原酶门静脉灌注后,应用胶原酶灌注的动物肝羟脯氨酸含量显著低于用生理盐水灌注的对照组,肝组织学检查也显示胶原酶治疗后肝硬化消退,肝肾功能检查未发现胶原酶的毒性反应。结论 门静脉灌注胶原酶可以促进已形成的肝硬化向正常肝组织结构逆转,并未发现对肝、肾组织毒性反应。%Objective To investigate whether portal collagenase administration can reverse liver cirrhosis. Methods Rabbits divided into 4 groups; group 1: Rabbits received carbon tetrachloride (CC14) subcutaneously (sc) for 12 weeks,then have an operation to put an cannulation in portal vein, collagenase portally for 4 weeks, group 2: Rabbits received CC14 sc for 12 weeks, then have an operation to put an cannulation in portal vein, normal saline portally for 4 weeks, group 3: Rabbits received olive oil sc for 12 weeks,then have an operation to put an cannulation in portal vein collagenase portally for 4 weeks, group 4: Rabbits received olive oil sc for 12 weeks,then have an operation to put an cannulation in portal vein normal saline portally for 4 weeks. Then take tissues of liver, portal vein, brain,kidney, lung and heart in 4 groups. After the zoopery,use chloramine T to test the hydroxypro-line content in liver tissues after

  11. Preparation of TiO2/ZnO Nanotubes and Their Photocatalytic Activity%TiO2/ZnO纳米管的制备及其光催化性能

    Institute of Scientific and Technical Information of China (English)

    杨硕; 尹荔松; 阳素玉; 龚青

    2011-01-01

    Highly ordered TiO2 nanotube arrays were prepared by electrochemical anodization and TiO2/ ZnO nanotube arrays were also fabricated by slope capillary assembly technique with ZnO sol self-assembly on the surface of amorphous TiO2 due to super-hydrophilic properties of nanotubes. The impact of anodizing parameters on the morphology of nanotubes was discussed and the structure and shape of samples were characterized by X-ray diffractometer(XRD) and field emission scanning electron microscope (FE-SEM). The photocatalytic degradation activities of chloramine phosphorus were evaluated by analyzing the influence of annealing temperature, the diameter of tube, the length of tube and composite ratio of TiO2/ZnO on photocatalytic degradation. The results show that annealing temperature, the diameter of tube and composite ratio of ZnO are the main factors. As for TiO2/ZnO nanotubes with the diameter of 97 nm and the length of 315. 8 run, the best composite ratio of TiO2/ZnO is 4. 2% (mass fraction) and the degradation rate achieves 78% after 5 h.%采用电化学阳极氧化法制备了高度有序的TiO2纳米管阵列,并利用纳米管的光致超亲水特性,采用斜面毛细组装技术在无定形TiO2表面自组装ZnO溶胶后退火制备了TiO2/ZnO复合纳米管.探讨了阳极氧化各参数对纳米管形貌的影响.利用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)等方法对样品的结构和形貌进行了表征.以有机磷农药氯胺磷为光催化降解对象,研究了焙烧温度、管径、管长和TiO2/ZnO复合比例等因素对降解效果的影响.结果表明,焙烧温度、管径以及ZnO复合比例对光催化降解率影响较大.对于管径97nm、管长315.8nm的TiO2/ZnO纳米管,ZnO最佳复合比例为4.2%(质量分数),5h后降解率达到78%.

  12. New Methods for Labeling RGD Peptides with Bromine-76

    Directory of Open Access Journals (Sweden)

    Lixin Lang, Weihua Li, Hong-Mei Jia, De-Cai Fang, Shushu Zhang, Xilin Sun, Lei Zhu, Ying Ma, Baozhong Shen, Dale O. Kiesewetter, Gang Niu, Xiaoyuan Chen

    2011-01-01

    Full Text Available Direct bromination of the tyrosine residues of peptides and antibodies with bromine-76, to create probes for PET imaging, has been reported. For peptides that do not contain tyrosine residues, however, a prosthetic group is required to achieve labeling via conjugation to other functional groups such as terminal α-amines or lysine ε-amines. The goal of this study was to develop new strategies for labeling small peptides with Br-76 using either a direct labeling method or a prosthetic group, depending on the available functional group on the peptides. A new labeling agent, N-succinimidyl-3-[76Br]bromo-2,6-dimethoxybenzoate ([76Br]SBDMB was prepared for cyclic RGD peptide labeling. N-succinimidyl-2, 6-dimethoxybenzoate was also used to pre-attach a 2, 6-dimethoxybenzoyl (DMB moiety to the peptide, which could then be labeled with Br-76. A competitive cell binding assay was performed to determine the binding affinity of the brominated peptides. PET imaging of U87MG human glioblastoma xenografted mice was performed using [76Br]-BrE[c(RGDyK]2 and [76Br]-BrDMB-E[c(RGDyK]2. An ex vivo biodistribution assay was performed to confirm PET quantification. The mechanisms of bromination reaction between DMB-c(RGDyK and the brominating agent CH3COOBr were investigated with the SCRF-B3LYP/6-31G* method with the Gaussian 09 program package. The yield for direct labeling of c(RGDyK and E[c(RGDyK]2 using chloramine-T and peracetic acid at ambient temperature was greater than 50%. The yield for [76Br]SBDMB was over 60% using peracetic acid. The conjugation yields for labeling c(RGDfK and c(RGDyK were over 70% using the prosthetic group at room temperature. Labeling yield for pre-conjugated peptides was over 60%. SDMB conjugation and bromination did not affect the binding affinity of the peptides with integrin receptors. Both [76Br]Br-E[c(RGDyK]2 and [76Br]BrDMB-E[c(RGDyK]2 showed high tumor uptake in U87MG tumor bearing mice. The specificity of the imaging tracers

  13. Source Water Management for Disinfection By-Product Control using New York City's Operations Support Tool and On-Line Monitoring

    Science.gov (United States)

    Weiss, W. J.; Becker, W.; Schindler, S.

    2012-12-01

    The United States Environmental Protection Agency's 2006 Stage 2 Disinfectant / Disinfection Byproduct Rule (DBPR) for finished drinking waters is intended to reduce overall DBP levels by limiting the levels of total trihalomethanes (TTHM) and five of the haloacetic acids (HAA5). Under Stage 2, maximum contaminant levels (MCLs), 80 μg/L for TTHM and 60 μg/L for HAA5, are based on a locational running annual average for individual sites instead of as the system-wide quarterly running annual average of the Stage 1 DBPR. This means compliance will have to be met at sampling locations of peak TTHM and HAA5 concentrations rather than an average across the entire system. Compliance monitoring under the Stage 2 DBPR began on April 1, 2012. The New York City (NYC) Department of Environmental Protection (DEP) began evaluating potential impacts of the Stage 2 DBPR on NYC's unfiltered water supply in 2002 by monitoring TTHM and HAA5 levels at various locations throughout the distribution system. Initial monitoring indicated that HAA5 levels could be of concern in the future, with the potential to intermittently violate the Stage 2 DBPR at specific locations, particularly those with high water age. Because of the uncertainty regarding the long-term prospect for compliance, DEP evaluated alternatives to ensure compliance, including operational changes (reducing chlorine dose, changing flow configurations to minimize water age, altering pH, altering source water withdrawals); changing the residual disinfectant from free chlorine to chloramines; and engineered treatment alternatives. This paper will discuss the potential for using DEP's Operations Support Tool (OST) and enhanced reservoir monitoring to support optimization of source water withdrawals to minimize finished water DBP levels. The OST is a state-of-the-art decision support system (DSS) to provide computational and predictive support for water supply operations and planning. It incorporates a water supply system

  14. Phenotype of the taurine transporter knockout mouse.

    Science.gov (United States)

    Warskulat, Ulrich; Heller-Stilb, Birgit; Oermann, Evelyn; Zilles, Karl; Haas, Helmut; Lang, Florian; Häussinger, Dieter

    2007-01-01

    ; Liu et al., 1992; Ramamoorthy et al., 1994; Schloss et al., 1994; Smith et al., 1992; Uchida et al., 1992; Vinnakota et al., 1997; Yancey et al., 1975). Taurine is not incorporated into proteins. It is involved in cell volume regulation, neuromodulation, antioxidant defense, protein stabilization, stress responses, and via formation of taurine-chloramine in immunomodulation (Chapman et al., 1993; Green et al., 1991; Huxtable, 1992; Timbrell et al., 1995). On the basis of its functions, taurine may protect cells against various types of injury (Chapman et al., 1993; Green et al., 1991; Huxtable, 1992; Kurz et al., 1998; Park et al., 1995; Stapleton et al., 1998; Timbrell et al., 1995; Welch and Brown, 1996; Wettstein and Häussinger, 1997). In order to examine the multiple taurine functions, murine models have several intrinsic advantages for in vivo research compared to other animal models, including lower cost, maintenance, and rapid reproduction rate. Further, experimental reagents for cellular and molecular studies are widely available for the mouse. In particular, mice can be easily genetically manipulated by making transgene and knockout mice. This chapter focuses on the phenotype of the TAUT-deficient murine model (taut-/-; Heller-Stilb et al., 2002), which may help researchers elucidate the diverse roles of taurine in development and maintenance of normal organ functions and morphology.

  15. Comparative biodistribution profile of [131I]VIP and [131I]VIP10-28

    Directory of Open Access Journals (Sweden)

    Maria Tereza Colturato

    2005-10-01

    Full Text Available Various tumor cells express significantly higher amounts of VIP receptors (VIPR that provided the basis for the clinical use of radiolabeled VIP for the in vivo localization of tumors. This work studied the labeling of VIP and VIP10-28 with iodine-131 to compare the biological distribution of the labeled compounds in Nuce mice and the affinity for tumor cells. Both VIP and VIP10-28 peptides contain two tyrosine residues, in positions 10 and 22, that are theoretically equally susceptible to radioiodination employing oxidative electrophilic substitution using oxidizing agents like Chloramine T. Radiochemical purity of the reaction mixture was determined by electrophoresis and HPLC. The VIP peptide and the fragment were labeled with radioiodine with good radiochemical yield (above 96%. Suitable, but important differences can be observed in biological distribution studies. Comparatively, blood clearance was faster for labeled VIP and perhaps because of this, the uptake in tumor was lower, especially during the first hour. These differences observed in the biological distribution of the compounds can be related to the lipophilicity of the labeled compounds.Várias células tumorais expressam significantemente uma alta quantidade de receptores VIP (VIPR que determinam a base para o uso clínico de VIP radiomarcado para localização de tumores in vivo. Foi estudado neste trabalho a marcação do VIP e do fragmento VIP10-28 com iodo-131 comparando a distribuição biológica dos compostos marcados em camundongos Nude e sua afinidade pelas células tumorais. Ambos os peptídeos, VIP e VIP10-28. contém dois resíduos de tirosina nas posições 10 e 22, que teoricamente são igualmente susceptíveis pela substituição eletrofílica oxidativa do radioiodo utilizando Cloramina T como agente oxidante. A pureza radioquímica da mistura de reação foi determinada por eletroforese e cromatografia líquida de alta eficiência (CLAE. O VIP e fragmento foram

  16. 儿童恒牙全脱出牙周组织预后的回顾性研究%Retrospective study about periodontal ligament healing of replanted permanent teeth in children

    Institute of Scientific and Technical Information of China (English)

    白洁; 赵玉鸣; 秦满

    2015-01-01

    Objective:To analyze the prognosis about periodontal ligament healing of replanted perma-nent teeth in children and to examine the associated factors.Methods: The sample consisted of 49 children with 61 avulsed permanent teeth, whose injuries had been managed in the period from 2000 to 2012.The clinical data of replanted teeth were collected, and the follow-up period was no less than 12 months .The factors were analyzed in relation to postoperative outcomes, classified as functional periodon-tal healing ( FH ) , infection-related ( inflammatory ) resorption ( IRR ) and replacement resorption ( RR) .Results:The functional healing rate was 23.0%, while replacement resorption rate was 72.1%. The replacement resorption ( ankylosis ) was usually observed earlier by clinical examination than by radiographic examination.86.0% (40/47) resorptive processes were diagnosed within the first year. Physiological storages, such as milk, saline and saliva were significantly better to periodontal ligament healing than nonphysiological storages, such as tap water and sterilizing solutions ( chloramine and alco-hol) .Functional healing was found significantly more frequent in canines and premolars.Conclusion:The factor significantly affecting periodontal ligament healing is storage medium.Replacement resorption is the most common type of root resorption.The replacement resorption diagnosis must combine the radio-graphic examination with the clinical examination.It is better to follow up more than 1 year after tooth re-plantation.%目的:对儿童恒牙全脱出后再植的病例进行回顾性研究,观察再植牙的牙周组织预后类型和各类根吸收出现的时间,分析影响再植牙牙周组织预后的可能因素。方法:对2000年至2012年在北京大学口腔医院就诊的儿童恒牙全脱出系统病历进行回顾性研究,要求观察期大于12个月,记录再植牙的预后和各类牙根吸收出现的时间,分析影响再植牙预后的相

  17. Rapid and sensitive method for simultaneous determination of nine N-nitrosamines in drinking water by UPLC-MS/MS%超高效液相色谱串联质谱快速测定饮用水中9种N-亚硝胺的新方法

    Institute of Scientific and Technical Information of China (English)

    罗茜; 王东红; 王炳一; 张子秋; 王子健

    2011-01-01

    N-Nitrosomines, a group of probable human carcinogens, has been detected as a disinfection by-products (DBPs) in drinking water.To comprehensively investigate the occurrence of possible nitrosamines in drinking water, an ultra-performance liquid chromatography-tandem mass spectrometry technique was developed to detect both thermally stable and unstable total nine nitrosamines.With optimized liquid chromatography column, mobile phases, and triple quadrupole conditions, UPLC-MS/MS enabled the determination of ng/L levels of nine nitrosamines.Isotope-labeled N-nitrosodimethylamine-d6 (NDMA-d6) was used as the surrogate standard for determining recovery, and N-nitrosodi-n-propylamine-d14 (NDPA-d14) was used as the internal standard for quantification.The limits of detection (LOD) and limits of quantification (LOQ) for NDMA were estimated to be 0.1 and 1 ng/L, NDPA were 2.5 and 10 ng/L,and other seven nitrosamines were 0.5 and 2.0 ng/L, respectively, which were less than maximum permissible concentration by US EPA.The occurrence and distribution of N-nitrosamines in different treatment processes (raw water, deposition and finished water) in drinking water treatment plants with chloramines disinfectant were determined using UPLC-MS/MS with direct injection method.The three nitrosamines with carcinogen risk, NDMA is found in finished water with concentration 3.5 ng/L, NMEA and NDEA were lower than LOQ.This indicated N-nitrosamines in drinking water that could not lead to the health risk for urban residents.%N-亚硝胺是潜在的人类致癌物,是近年来关注的一类饮用水消毒副产物,同时也是环境分析研究的热点.本文建立了超高效液相色谱(UPLC)串联质谱快速测定饮用水中9种N-亚硝胺的新方法,讨论了色谱柱和流动相对分离9种N-亚硝胺的影响,优化了多级反应质谱(MRM,MS/MS)条件.二甲基亚硝胺-d6为贮存和回收率内标,亚硝基二丙胺-d14为定量内标,UPLC-MS/MS能够直接快速检测饮

  18. 平阳霉素-活性炭纳米微粒行口腔癌淋巴化疗的靶向性评价%Lymphatic targeting study of pingyangmycin-activated carbon nanoparticles treating oral cancer lymph node metastasis

    Institute of Scientific and Technical Information of China (English)

    孙明磊; 谢卫红; 王昌美; 温玉明

    2011-01-01

    目的 观察平阳霉素-活性炭纳米微粒(PYM-CH-NP)经鼠癌周黏膜下给药后,活性药物在体内各组织器官中的分布情况,探讨PYM-CH-NP对淋巴结转移灶的靶向性.方法 采用改良氯胺T法将125I标记平阳霉素(PYM),应用淋巴结高转移癌株U14建立昆明小鼠颈淋巴结转移模型.将360只颈淋巴结转移模型小鼠随机分为PYM-CH-NP组、PYM组和阴性对照组,分别于癌周黏膜下注射PYM-CH-NP、PYM水溶液和空白活性炭纳米微粒,给药后0.5、1、4、8、12、24、48、72、96、120、144、168 h处死动物,取血、心、肝、脾、肺、肾和颈淋巴结,检测各时间点各组织器官内平阳霉素的放射活性,计算各样本单位重量的药物放射活性(比放射活性),并计算药物的选择性指数(SI)和靶向指数(TI).结果 PYM-CH-NP组各时间点颈淋巴结内药物浓度显著高于PYM组(P<0.001),4 h后血、心、肝、脾、肺、肾等器官中药物浓度均低于PYM组(P<0.001).PYM组各时间点的SI均小于1,而PYM-CH-NP组SI和TI最低值为1.793和1.562,最高为72 h时的68.126和14.623.结论 PYM-CH-NP可显著增加淋巴结转移灶内的药物浓度,同时非靶器官药物分布减少,降低了药物的全身毒副反应.%Objective To investigate the drug distribution in tissues of cervical lymph node metastasis mice model after submucosa adjacent cancer injection of pingyangmycin-activated carbon nanoparticles (PYM-CH-NP) and evaluate the lymph targeting effect of PYM-CH-NP. Methods Pingyangmycin (PYM) was radiolabeled with 125I by modified the chloramine T method. Cervical lymph node metastasis mice model was established by buccal submucosa inoculation of a high lymph metastasis cell line U14 cancer cell. 360 mice models burdened with cervical lymph metastasis were randomly divided into 3 groups. PYM group was treated with PYM water solution, PYM-CH-NP group was treated with PYM-CH-NP. Negative control group was injected with activated carbon

  19. Study on biodistribution of 131 iodine labeled monoclonal antibody D-D3 against pro-gastrin-releasing peptide(31-98) in healthy Kunming mice%抗ProGRP(31-98)单克隆抗体D-D3的131I标记及其体内生物学分布研究

    Institute of Scientific and Technical Information of China (English)

    陈传新; 石怡珍; 杨仪; 唐军; 刘增礼; 徐巧玲

    2011-01-01

    Objective To study the 131I labeling methods, stability, and biological distribution pattern of D-D3 antibody against pro-gastrin-releasing peptide 31-98(ProGRP(31-98) ). Methods The radioiodination of D-D3 antibody was performed using the chloramine-T method. The radiochemical purity was determined through thin-layer chromotography. 131I-D-D3 was injected into the healthy Kunming mice via a tail vein, and the % ID/g for various organs was obtained, and then, the biodistribution and pharmacokinetics of 131 I-D-D3 antibody in healthy Kunming mice were studied. Results The 131 I-D-D3 labeling rate was (86.56 ± 3.8) %. The radiochemical purity of 131 I-D-D3 was (99.27 ± 0. 6)%. After 48 h incubating in 37 ℃ water bath, the radiochemical purity was (88.38 ± 0.4)%. While being mixed 24 h with healthy human serum, the radiochemical purity was still more than (64.43 ± 0.7)%. The metabolism of 131I-D-D3 in healthy Kunming mice was consistent with a two-compartment model with first-order absorption, T1/2α and T1/2β was 0.25,37.89 h, respectively. Conclusion The labeling efficiency and radiochemical purity of 131 I-D-D-D3 are high and stable. 131I-D-D3 is a promising radioimmunoimaging reagent for small cell lung cancer(SCLC).%目的 探讨抗胃泌素释放肽前体(ProGRP)(31-98)单克隆抗体D-D3的131I标记方法 及其在健康昆明小鼠体内的生物学分布规律与特点.方法 采用氯胺-T法用131I标记单克隆抗体D-D3,利用纸层析法测定其标记率、放化纯度和稳定性.取健康昆明小鼠50只,随机分为10组,每组5只,自昆明小鼠尾静脉注射131I-D-D3 1.48 kBq/100 μL(4 μCi/100 μL),各组小鼠分别于注射后5、15、30 min及1、2、4、8、12、24、48 h处死,取血液、心脏、肝脏、脾脏、肺脏、肾脏、胃、小肠、骨骼(右下肢)、肌肉(右下肢)和脑组织,称质量(g)后测放射性计数(cpm),计算各脏器组织的每克组织百分注射剂量率(%ID

  20. Effects of “two fairy decoction”(二仙汤) and its decomposed recipe on gonadotropin-releasing hormone secreted by GT1-7 cell line%二仙汤及其拆方对GT1-7细胞株GnRH分泌的影响

    Institute of Scientific and Technical Information of China (English)

    杨颖; 陈名道; 李凤英; 唐金凤; 高国锋; 陈家伦

    2001-01-01

    目的:GT1-7细胞株是转入了猴病毒-40的T抗原(SV40T)癌基因的促性腺激素释放激素(GnRH)神经内分泌细胞株。本实验观察补肾方二仙汤及其“温肾”、“滋阴”两个拆方对GT1-7细胞株释放GnRH的影响。方法:(1)3个月龄的SD雄性大鼠予成人每公斤体重的10倍剂量灌服中药4日,于末次给药后1或2小时腹主动脉取血,制备成药物血清。(2)氯胺T法标记GnRH,建立稳定可靠的放免标准曲线。(3)GT1-7细胞用含10%、30%或50%药物血清的培养液孵育24或48小时,收集上清液做放射免疫测定。结果:(1)末次给药后1、2小时取血的二仙汤药物血清均能刺激GnRH释放,以1小时给药血清效果最好。(2)10%浓度的药物血清为最有效剂量。(3)二仙汤全方及其两个拆方均能促进GnRH释放,以全方效果最显著。结论:中医“肾主生殖”的功能似涉及下丘脑GnRH神经元及其调控性腺轴的功能,二仙汤及其全方能够直接调节GnRH的分泌。%To investigate the effects of kidney tonifying formula “two fairy decoction”(TFD,二仙汤) and its two decomposed recipes “kidney warming”(温肾) and “yin nourishing”(滋阴) of ingredients on GT1-7 cell line which was developed by targeting the SV40T antigen to gonadotropin-releasing hormone(GnRH) neuron in transgenic mouse.Methods:(1)Three months-aged male rats were orally administered herbal extract for four days,sera were obtained from rats one or two hours after the last administration.(2)GnRH was measured by radioimmunoassay(RIA) with chloramine T iodination,and the detectable limit was 0.25 pg.(3)Cells were maintained for 24 or 48 hours with DMEM which contained 10%,30% and 50% rat serum,and samples were collected for RIA measurements.Results:(1)Both sera obtained from one and two hours after the last oral herb administration of TFD stimulated GnRH secretion,the former seemed more potent.(2

  1. Utilização do dióxido de cloro e do ácido peracético como substitutos do hipoclorito de sódio na sanitização do cheiro-verde minimamente processado Using chlorine dioxide and peracetic acid as substitutes for sodium hypocloride in the sanitization of minimally processed green seasoning

    Directory of Open Access Journals (Sweden)

    Silvana Mariana Srebernich

    2007-12-01

    propiciaram melhores resultados no controle microbiano. Entretanto, de acordo com os padrões existentes na legislação em vigor para Salmonella (ausência em 25 g de amostra e para E. coli (Minimally processed vegetables are ready to eat products that should be free of pathogenic microorganisms. These vegetables must be washed in good quality water, followed by the addition of a sanitizer to reduce the microbial count and minimize the product's deterioration, increasing its preservation and making it microbiologically safer. Sodium hypochlorite is the only sanitizer for this purpose allowed by Brazilian legislation. Although efficient, its use has been questioned because it is a precursor of organic chloramines, compounds of high carcinogenic potential. Many sanitizers have been proposed as substitutes of sodium hypochlorite in the disinfection of vegetables, including chlorine dioxide and peracetic acid. Therefore, based on microbial analyses, this research aimed to test the efficiency of chlorine dioxide (10, 25 and 50 ppm /2, 5 and 10 minutes and peracetic acid (60, 80 and 100 ppm/5, 10 and 15 minutes in comparison with sodium hypochlorite (120 ppm/15 minutes in the control of natural microbiota of minimally processed green seasoning. The green seasoning, which consists of fresh parsley and welsh onions, was washed in various concentrations of sanitizing solutions for given times and then processed to obtain sample of green seasoning. The control sample was washed only in tap water. The treatments were repeated on 3 distinct occasions at 4-month intervals, and 3 samples (packages of 150 g were collected from each treatment for microbial analysis of pathogenic Salmonella sp., total coliforms, Escherichia coli and total fungal count. The results of these analyses after statistical evaluation indicated that higher concentrations and longer sanitizing treatments led to better microbial control. However, according to the standards in the current legislation on Salmonella sp

  2. 玷污层及不同根尖倒充填材料对根尖倒充填后微渗漏影响的体外研究%In vitro studies of smear layer and retrograde fil ing material impact on apical microleakage after down -fil ed

    Institute of Scientific and Technical Information of China (English)

    李永立; 张丽萍; 武燃; 刘鹏

    2015-01-01

    Objective:Af ect apical microleakage after fil ing material with the smear layer on the application of three root canal.Method:Select 64 single root canal teeth after root canal preparation,cold lateral condensation gut a -percha root canal fil ing,after removal of the apical root canal preparation down.Randomly divided into experimental group and control group (n =30 each).Experimental group:17%EDTA +1% chloramine -T remove the smear layer,In the control group:5ml saline.Randomly selected from two groups do SEMobservation.Each group was randomly divided into 3 groups were MTA,GIC,HG were down fil ing,taking root canal fil ing the upper section.Placing micro -leakage model.First detected in concentrations ranging from 0 days 1,2,4,7,10,15,20,30 crown direction leaked square root of glucose.Results:MTA's closure at each time point were superior GIC,HG.Dif erent back molars same treatment (re-moval or retention)under the fil ing material compared pairwise dif erences were statistical y significant P 0.05).Conclusion:MTA apical closure than GIC,HG,application MTA,GIC as a retrograde fil ing material after removal of the smear lay-er apical sealing bet er,but no dif erence in HG.%目的:探讨对应用3种根管倒充填材料玷污层去留对根尖微渗漏的影响,以期为临床应用提供依据。方法:选取64颗单根管牙,常规根管预备后,冷牙胶侧向加压充填根管,根尖切除后进行根管倒预备,将其随机分为实验组与对照组(每组各32颗)。实验组:17%EDTA +2%氯亚明去除玷污层,对照组:用5mL 生理盐水冲洗。从2组中随机抽取 2颗牙做扫面电镜检测。各组分别用 MTA、GIC 和 HG 进行倒充填。去除根管上段充填物,将离体牙置于微渗漏模型,于第1、2、4、7、10、15、20和30天检测从冠方向根方漏出的葡萄糖的浓度。结果:MTA 的封闭性在各个时间点均优于 GIC、HG。离体牙同一种处理方法(去除或保留

  3. Risk assessment of Pseudomonas aeruginosa in water.

    Science.gov (United States)

    Mena, Kristina D; Gerba, Charles P

    2009-01-01

    . 1986). Outbreaks have also been reported from exposure to P. aeruginosa in swimming pools and water slides. Although P. aeruginosa has a reputation for being resistant to disinfection, most studies show that it does not exhibit any marked resistance to the disinfectants used to treat drinking water such as chlorine, chloramines, ozone, or iodine. One author, however, did find it to be slightly more resistant to UV disinfection than most other bacteria (Wolfe 1990). Although much has been written about biofilms in the drinking water industry, very little has been reported regarding the role of P. aeruginosa in biofilms. Tap water appears to be a significant route of transmission in hospitals, from colonization of plumbing fixtures. It is still not clear if the colonization results from the water in the distribution system, or personnel use within the hospital. Infections and colonization can be significantly reduced by placement of filters on the water taps. The oral dose of P. aeruginosa required to establish colonization in a healthy subject is high (George et al. 1989a). During dose-response studies, even when subjects (mice or humans) were colonized via ingestion, there was no evidence of disease. P. aeruginosa administered by the aerosol route at levels of 10(7) cells did cause disease symptoms in mice, and was lethal in aerosolized doses of 10(9) cells. Aerosol dose-response studies have not been undertaken with human subjects. Human health risks associated with exposure to P. aeruginosa via drinking water ingestion were estimated using a four-step risk assessment approach. The risk of colonization from ingesting P. aeruginosa in drinking water is low. The risk is slightly higher if the subject is taking an antibiotic resisted by P. aeruginosa. The fact that individuals on ampicillin are more susceptible to Pseudomonas gastrointestinal infection probably results from suppression of normal intestinal flora, which would allow Pseudomonas to colonize. The process of

  4. 抗ProGRP(31-98)单克隆抗体E-B5的131I标记及体内生物分布研究%The in vivo pharmacokinetics study of anti-ProGRP(31-98) monoclonal antibody E-B5

    Institute of Scientific and Technical Information of China (English)

    徐巧玲; 周小林; 石怡珍; 杨君; 刘增礼

    2009-01-01

    Objective Progastrin-releasing peptide(31-98)(ProGRP(31-98)is a specific tumor marker in patients with small cell lung cancer (SCLC). E-B5 antibody against ProGRP(31-98) was produced by China Institute for Radiation Protection. The aim of this study was to explore the 131I labeling methods, stability, immunological activity and biological distribution pattern of E-B5 antibody against ProGRP(31-98). Methods Chloramine-T method was used for 131I labeling E-B5 antibody. Labeling efficiency, radiochemical purity and stability were estimated by using paper chromatography method. Immunological activity of 131I-E-B5 was detected with cell conjugation assay. After healthy Kunming mice were injected with 131I-E-B5 antibody through tail veil, the biodistribution and pharmacokinetics of 131l-E-B5 antibody in healthy Kunming mice were studied. Continuous images of the nude mice beating SCLC were carried out at different time points af-ter injection of 131I-E-B5 antibody. Continuous variables were expressed as x±s and compared by t-test with SPSS 13.0 software. Results The labeling efficiency and radiochemical purity of131I-E-B5were 90.8%, 99.28%, respectively. The radiochemical purity still maintained above 70% after incubation in water bath at 37℃ for 24 h. After incubation with healthy serum for 24 h, the radiochemical purity still reached 68.1%. The immunobinding ratios were 71.6% and 33.2% for NCI-H446 cells and A549 cells respective-ly. The in vivo distribution and elimination of 131I-E-B5 antibody were consistent with a first-order and two-compartment model, t1/2α=0.2 h, t1/2α= 8.35 h. The metabolism of 131I-E-B5 antibody mainly depended on liver and kidney and with rapid elimination in blood. Condusions 131I-E-B5 antibody not only has high la-beling efficiency and radioehemical purity, but also has good stability and keeps good immunological activi-ty. 131I-E-B5 is a promising agent of radioimmunoimaging and radioimmunotherapy of SCLC.%目的 研究抗胃泌素释

  5. Effect of intestinal ischemia-reperfusion injury on the leptin levels in serum and adipose tissue%肠缺血再灌注损伤对血清及脂肪组织Leptin水平的影响

    Institute of Scientific and Technical Information of China (English)

    林季; 颜光涛; 王录焕; 郝秀华; 张凯; 薛辉

    2004-01-01

    BACKGROUND: Recent studies suggest that adipose tissue is not only the reservation of fat, but also a multi-potential endocrine organ secreting many functional cytokines. Leptin is a protein specifically secreted by adipose tissue, and primarily reduces food-intake and promotes energy expenditure.OBJECTIVE: To explore the effect of intestinal ischemia-reperfusion injury on leptin levels in serum and adipose tissue, and find out the role of leptin playing in acute inflammatory responses.DESIGN: A completely random self-and mutual-control experiment.SETTING and MATERIALS: The experiment was collected and completed in Research Laboratory of Biochemistry, General Hospital of Chinese PLA.Three male New Zealand white rabbits and fifty-four male Sprague-Dawley rats were used for experimental use.INTERVENTIONS: New Zealand white rabbits were immunized to obtain anti-leptin, leptin antigen was iodinated by chloramines-T method, thus we established a concise radioimmunoassay for murine leptin. An intestinal ischemia-reperfusion injury model of rats was established, and rats were divided randomly into six groups: sham-operation group(sham), 60-minute ischemia and 30-minute reperfusion group(I60-R30), I60-R90, I60-R150,I60-R240 and I60-R360; each group contained nine rats.MAIN OUTCOME MEASURES: The changes of leptin concentrations in serum and adipose tissue before and after ischemia-reperfusion injury were checked by the radioimmunoassay.RESULTS: Compared with self-control(before injury), serum leptin level of I60-R30 decreased significantly(t=2.3891, P<0.05), that of I60-R150 expressed a trend to increase and that of I60-R360 increased significantly ( t = - 2. 3437, P<0.05 ). Compared with sham after injury [ (9.88±1.87)μg/L], serum leptin level of I60-R240 expressed a trend to increase, that of I60-R360[ (19.43±2.84) μg/L] increased significantly( t = - 2. 8085, P <0.05) . Compared with sham after injury [ ( 11.12±1.27 ) ng], adipose leptin levels of I60-R30[ (4

  6. Preparation and lymphatic targeting study of pingyangmycin-activated charcoal nanoparticles%平阳霉素纳米活性炭的研制及其淋巴靶向性研究

    Institute of Scientific and Technical Information of China (English)

    孙明磊; 尚君兰; 王海斌; 王昌美; 温玉明

    2011-01-01

    Objective To explore the possibility of anticancer drug targeting to lymph metastasis using activated charcoal nanoparticles as a drug delivery carrier, the drug distribution in tissues of cervical lymph node metastasis mice model after submucosa adjacent cancer injection of pingyangmycin (PYM ) absorbed in activated charcoal nano-particles ( ACH-NP) and the lymph targeting effect of PYM-ACH-NP.Methods PYM-ACH-NP was prepared by mixed the ACH-NP + PYM + saline and shaken for 20 min. The absorbency of PYM on ACH-NP was evaluated. Cervical lymph node metastasis mice model was established by buccal submucosa implantation of a high lymph metastasis cell line U14 cancer cells (5 × 10 /L). PYM was radiolabeled with 125I by the modified chloramine T method. Thirty Kunming mice models burdened with cervical lymph metastasis were randomly divided into control group, PYM-treated group and PYM-ACH-NP-treated group. The animal in each group was injected with 0. 2 mL saline or corresponding drugs (equal to 10 mg/kg PYM) respectively. The radioactivity of PYM in blood, heart, liver, spleen, lung,kidney and cervical lymph node was detected 72 h after administration. Specific radioactivity of each sample was calculated. Results The average diameter of PYM-ACH-NP was 176 nm. The absorbency of PYM on ACH-NP was increased with the increased ratio of ACH-NP to PYM. In PYM-CH-NP group, specific radioactivity of PYM was significantly higher in cervical lymph node ( 148. 72 ± 29. 35 ) cpm/mg than in PYM group ( 10. 17 ±2. 11) cpm/mg ( P <0. 01 ) , meanwhile the specific radioactivity of drug in the blood, heart, liver, spleen, lung and kidney of PYM-CH-NP group was (2. 18 ±0. 39), (1. 19 ±0.21) ,(2.41 ±0.50) , (1.09 ±0.24) , (1.95 ±0.47) and (2.21 ±0.44) cpm/mg respectively, which was significantly lower than in PYM group (17. 22 ± 3. 04) , (2. 48 ± 0. 47 ), (6. 94 ± 1. 38 ), (4. 12 ±0.79), (8. 25 ±2.04), (18. 83 ±3. 89) cpm/mg. The uptake of PYM in the blood, heart

  7. 益气养阴、活血化瘀中药对糖尿病大鼠脂代谢紊乱及蛋白质非酶糖基化的影响%Effect of Chinese herb for benefiting qi, nourishing yin, activating blood circulation and resolving stasis on lipid metabolic disturbance and protein nonenzyme glycosylation in diabetic rats

    Institute of Scientific and Technical Information of China (English)

    戴红

    2005-01-01

    administered once every day in above 6 groups,and the treating course was 8 weeks. ③ Before treatment, on the 3rd, 6th and 8th weeks after treatment, fasting blood sugar was tested with One Touch Ⅱ tester. 8 weeks later, automatic biochemistry analyzer was used to assay triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDLC) and high-density lipoprotein cholesterol (HDLC). Thoracic aorta was collected swiftly and chloramine-T method was used to assay hydroxyproline content in the extract from aorta. Hydroxyproline content ×7.14=collagen content. Fluorescence spectrometer was used to assay the fluorescence degree of AGEs in collagen extract. ④ t test was applied for difference comparison of measurement data.MAIN OUTCOME MEASURES: ① Comparison of fasting blood sugar before and after treatment in each group. ② Comparison of blood lipid,collagen content and fluorescence degree of collagen-protein AGEs in thoracic aorta in 8 weeks after treatment in each group.RESULTS: At the end of experiment, 8, 4, 2, 2 and 3 rats were died in model group, insulin group, HXY low, middle and high-dose groups respectively, due to which, 12, 8, 11, 13, 13 and 12 rats entered result analysis in various groups respectively. ① Fasting blood sugar: Before treatment, it was higher remarkably in model and various treating groups compared with normal control (P < 0.01) and 8 weeks after treatment, it was lower remarkably in insulin group and various HXY groups compared with model group and before treatment (P < 0.01). ② Levels of TC, TG, LDLC in serum: Those in insulin and model groups were higher remarkably than normal control (P < 0.05-0.01). Those in insulin group and various HXY groups were lower remarkably than normal group (P < 0.05-0.01). ③ Level of HDLC: It was lower remarkably in insulin group and model group compared with normal control (P < 0.05-0.01), it was higher remarkably in HXY low and middle-dose groups compared with model group (P