WorldWideScience

Sample records for degradation product studies

  1. A long-term in vitro biocompatibility study of a biodegradable polyurethane and its degradation products

    NARCIS (Netherlands)

    van Minnen, B; Stegenga, B; van Leeuwen, MBM; van Kooten, TG; Bos, RRM

    2006-01-01

    The biological safety of degradation products from degradable biomaterials is very important. In this study a new method is proposed to test the cytotoxicity of these degradation products with the aim to save time, laboratory animals, and research funds. A biodegradable polyurethane (PU) foam was su

  2. A long-term in vitro biocompatibility study of a biodegradable polyurethane and its degradation products

    NARCIS (Netherlands)

    van Minnen, B; Stegenga, B; van Leeuwen, MBM; van Kooten, TG; Bos, RRM

    2006-01-01

    The biological safety of degradation products from degradable biomaterials is very important. In this study a new method is proposed to test the cytotoxicity of these degradation products with the aim to save time, laboratory animals, and research funds. A biodegradable polyurethane (PU) foam was su

  3. Thermal degradation of aqueous 2-aminoethylethanolamine in CO2 capture; identification of degradation products, reaction mechanisms and computational studies.

    Science.gov (United States)

    Saeed, Idris Mohamed; Lee, Vannajan Sanghiran; Mazari, Shaukat Ali; Si Ali, B; Basirun, Wan Jeffrey; Asghar, Anam; Ghalib, Lubna; Jan, Badrul Mohamed

    2017-01-01

    Amine degradation is the main significant problems in amine-based post-combustion CO2 capture, causes foaming, increase in viscosity, corrosion, fouling as well as environmental issues. Therefore it is very important to develop the most efficient solvent with high thermal and chemical stability. This study investigated thermal degradation of aqueous 30% 2-aminoethylethanolamine (AEEA) using 316 stainless steel cylinders in the presence and absence of CO2 for 4 weeks. The degradation products were identified by gas chromatography mass spectrometry (GC/MS) and liquid chromatography-time-of-flight-mass spectrometry (LC-QTOF/MS). The results showed AEEA is stable in the absence of CO2, while in the presence of CO2 AEEA showed to be very unstable and numbers of degradation products were identified. 1-(2-Hydroxyethyl)-2-imidazolidinone (HEIA) was the most abundance degradation product. A possible mechanism for the thermal degradation of AEEA has been developed to explain the formation of degradation products. In addition, the reaction energy of formation of the most abundance degradation product HEIA was calculated using quantum mechanical calculation.

  4. Degradation studies of pentoxifylline: Isolation and characterization of a novel gem-dihydroperoxide derivative as major oxidative degradation product.

    Science.gov (United States)

    Mone, Mahesh Kumar; Chandrasekhar, K B

    2010-11-02

    Pentoxifylline was subjected to various stress conditions and degradation profile was studied with conventional LCMS. Interestingly, under oxidative stress conditions the drug substance underwent distinct transformation to give rise to a single major degradation product. The structure of this product was elucidated using 1D, 2D NMR spectroscopy, high resolution mass spectrometry (Q-TOF LC/MS) and found to be a novel gem-dihydroperoxide, namely 1-(5,5-Bis-hydroperoxy-hexyl)-3,7-dimethyl-3,7-dihydro-purine-2,6-dione. An efficient stability indicating liquid chromatographic separation method was developed for pentoxifylline and its three degradation products (including two from base hydrolysis) using 1.8 microm, C18 reverse phase column and UHPLC. Baseline separation was achieved with a run time of 4 min. The analytical assay method was validated with respect to system suitability, specificity, linearity, range, precision, accuracy and robustness.

  5. Study of acaricide stability in honey. Characterization of amitraz degradation products in honey and beeswax.

    Science.gov (United States)

    Korta, E; Bakkali, A; Berrueta, L A; Gallo, B; Vicente, F; Kilchenmann, V; Bogdanov, S

    2001-12-01

    A study on the possible degradation of amitraz, bromopropylate, coumaphos, chlordimeform, cymiazole, flumethrin, and tau-fluvalinate during the storage of honey was carried out by HPLC. Except amitraz, the other acaricides are stable in this medium for at least 9 months. Degradation studies of amitraz in honey and beeswax were carried out; the degradation products detected in both matrices were 2,4-dimethylphenylformamide (DMF) and N-(2,4-dimethylphenyl)-N'-methylformamidine (DPMF). The reaction rate constants and the half-lives of the amitraz degradation in honey and wax were calculated. Amitraz was nearly completely degraded within 1 day in beeswax and within 10 days in honey. When amitraz-spiked combs are recycled into new beeswax, DMF was found to be the principal degradation product left in pure wax.

  6. Four new degradation products of doxorubicin:An application of forced degradation study and hyphenated chromatographic techniques

    Institute of Scientific and Technical Information of China (English)

    Dheeraj Kaushik; Gulshan Bansal

    2015-01-01

    Forced degradation study on doxorubicin (DOX) was carried out under hydrolytic condition in acidic, alkaline and neutral media at varied temperatures, as well as under peroxide, thermal and photolytic conditions in accordance with International Conference on Harmonization (ICH) guidelines Q1(R2). It was found extremely unstable to alkaline hydrolysis even at room temperature, unstable to acid hy-drolysis at 80 °C, and to oxidation at room temperature. It degraded to four products (O-I-O-IV) in oxidative condition, and to single product (A-I) in acid hydrolytic condition. These products were re-solved on a C8 (150 mm × 4.6 mm, 5μm) column with isocratic elution using mobile phase consisting of HCOONH4 (10 mM, pH 2.5), acetonitrile and methanol (65:15:20, / / ). Liquid chromatography-pho-todiode array (LC-PDA) technique was used to ascertain the purity of the products noted in LC-UV chromatogram. For their characterization, a six stage mass fragmentation (MS6) pattern of DOX was outlined through mass spectral studies in positive mode of electrospray ionization (+ESI) as well as through accurate mass spectral data of DOX and the products generated through liquid chromato-graphy-time of flight mass spectrometry (LC-MS-TOF) on degraded drug solutions. Based on it, O-I-O-IV were characterized as 3-hydroxy-9-desacetyldoxorubicin-9-hydroperoxide, 1-hydroxy-9-desacetyldox-orubicin-9-hydroperoxide, 9-desacetyldoxorubicin-9-hydroperoxide and 9-desacetyldoxorubicin, re-spectively, whereas A-I was characterized as deglucosaminyl doxorubicin. While A-I was found to be a pharmacopoeial impurity, all oxidative products were found to be new degradation impurities. The mechanisms and pathways of degradation of doxorubicin were outlined and discussed.

  7. Atmospheric degradation of 3-methylfuran: kinetic and products study

    Directory of Open Access Journals (Sweden)

    A. Tapia

    2011-04-01

    Full Text Available A study of the kinetics and products obtained from the reactions of 3-methylfuran with the main atmospheric oxidants has been performed. The rate coefficients for the gas-phase reaction of 3-methylfuran with OH and NO3 radicals have been determined at room temperature and atmospheric pressure (air and N2 as bath gases, using a relative method with different experimental techniques. The rate coefficients obtained for these reactions were (in units cm3 molecule−1 s−1 kOH = (1.13 ± 0.22 × 10−10 and kNO3 = (1.26 ± 0.18 × 10−11. Products from the reaction of 3-methylfuran with OH, NO3 and Cl atoms in the absence and in the presence of NO have also been determined. The main reaction products obtained were chlorinated methylfuranones and hydroxy-methylfuranones in the reaction of 3-methylfuran with Cl atoms, 2-methylbutenedial, 3-methyl-2,5-furanodione and hydroxy-methylfuranones in the reaction of 3-methylfuran with OH and NO3 radicals and also nitrated compounds in the reaction with NO3 radicals. The results indicate that, in all cases, the main reaction path is the addition to the double bond of the aromatic ring followed by ring opening in the case of OH and NO3 radicals. The formation of 3-furaldehyde and hydroxy-methylfuranones (in the reactions of 3-methylfuran with Cl atoms and NO3 radicals confirmed the H-atom abstraction from the methyl group and from the aromatic ring, respectively. This study represents the first product determination for Cl atoms and NO3 radicals in reactions with 3-methylfuran. The reaction mechanisms and atmospheric implications of the reactions under consideration are also discussed.

  8. Atmospheric degradation of 3-methylfuran: kinetic and products study

    Directory of Open Access Journals (Sweden)

    A. Tapia

    2010-10-01

    Full Text Available A study of the kinetics and products obtained from the reactions of 3-methylfuran with the main atmospheric oxidants has been performed. The rate coefficients for the gas-phase reaction of 3-methylfuran with OH and NO3 radicals have been determined at room temperature and atmospheric pressure (air and N2 as bath gases, using a relative method with different experimental techniques. The absolute rate coefficients obtained for these reactions were (in units cm3 molecule−1 s−1: kOH=(1.13±0.22×10−10 and kNO3=(1.26±0.18×10−11. These rate coefficients have been compared with those available in the literature. The products from the reaction of 3-methylfuran with OH, NO3 and Cl atoms in the absence and in the presence of NOx species have also been determined. The main reaction products obtained were chlorinated methylfuranones and hydroxy-methylfuranones for the reaction of 3-methylfuran with Cl atoms, 2-methylbutenedial, 3-methyl-2,5-furanodione and hydroxy-methylfuranones for the reaction of 3-methylfuran with OH and NO3 radicals and also nitrated compounds for the reaction with NO3 radicals. The results indicate that in all cases the main reaction path is the addition to the double bond of the aromatic ring followed by ring opening in the case of OH and NO3 radicals. The formation of 3-furaldehyde and hydroxy-methylfuranones (in the reactions of 3-methylfuran with Cl atoms and NO3 radicals confirmed the H-atom abstraction from the methyl group and from the aromatic ring, respectively. This study represents the first product determination for both Cl atoms and the NO3 radical in reactions with 3-methylfuran. The reaction mechanisms and atmospheric implications of the reactions under consideration are also discussed.

  9. The impact of charcoal production on forest degradation: a case study in Tete, Mozambique

    Science.gov (United States)

    Sedano, F.; Silva, J. A.; Machoco, R.; Meque, C. H.; Sitoe, A.; Ribeiro, N.; Anderson, K.; Ombe, Z. A.; Baule, S. H.; Tucker, C. J.

    2016-09-01

    Charcoal production for urban energy consumption is a main driver of forest degradation in sub Saharan Africa. Urban growth projections for the continent suggest that the relevance of this process will increase in the coming decades. Forest degradation associated to charcoal production is difficult to monitor and commonly overlooked and underrepresented in forest cover change and carbon emission estimates. We use a multitemporal dataset of very high-resolution remote sensing images to map kiln locations in a representative study area of tropical woodlands in central Mozambique. The resulting maps provided a characterization of the spatial extent and temporal dynamics of charcoal production. Using an indirect approach we combine kiln maps and field information on charcoal making to describe the magnitude and intensity of forest degradation linked to charcoal production, including aboveground biomass and carbon emissions. Our findings reveal that forest degradation associated to charcoal production in the study area is largely independent from deforestation driven by agricultural expansion and that its impact on forest cover change is in the same order of magnitude as deforestation. Our work illustrates the feasibility of using estimates of urban charcoal consumption to establish a link between urban energy demands and forest degradation. This kind of approach has potential to reduce uncertainties in forest cover change and carbon emission assessments in sub-Saharan Africa.

  10. Spectroscopic study of degradation products of ciprofloxacin, norfloxacin and lomefloxacin formed in ozonated wastewater.

    Science.gov (United States)

    Liu, Chen; Nanaboina, Venkateswarlu; Korshin, Gregory V; Jiang, Wenju

    2012-10-15

    This study addressed the formation and properties of degradation products of ciprofloxacin, norfloxacin and lomefloxacin formed during ozonation of secondary wastewater effluent containing these fluoroquinolone antibiotics. The generation of the degradation products was interpreted in the context of transformations of effluent organic matter (EfOM) tracked via absorbance measurements. The structures of 20 degradation products were elucidated for ciprofloxacin and norfloxacin, respectively. 27 degradation products were identified for lomefloxacin. The prevalent oxidation pathways were suggested based on the structures of the identified products formed in the absence and presence of the hydroxyl radical scavenger t-butanol. These pathways were largely similar for all studied fluoroquinolones and involved attacks on the piperazine ring and the quinolone structure. The quinolone ring remained intact in the presence of t-butanol thus indicating that this functional group could only be oxidized by OH radicals while the piperazine ring was readily oxidized by molecular ozone. The cleavage of the quinolone moiety that resulted in several identified degradation products occurred via the attack by hydroxyl radicals on the carbon-carbon double bond adjacent to the carboxylic acid group. Lomefloxacin had more diverse oxidation products due to the presence of a methyl group on its piperazinyl ring. The concentrations of the identified degradation products behaved non-monotonically as a function of ozone dose or treatment time, yet exhibited interpretable correlations versus changes of EfOM absorbance. Examination of these correlations allowed developing a novel approach for elucidating the transformations of fluoroquinolone antibiotics during ozonation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Study of the effect of the fibre mass UP2 degradation products on radionuclide mobilisation

    Energy Technology Data Exchange (ETDEWEB)

    Duro, Lara; Grive, Mireia; Gaona, Xavier; Bruno, Jordi [Amphos 21 Consulting S.L., Barcelona (Spain); Andersson, Thomas; Boren, Hans; Dario, Maarten [Linkoeping Univ., Linkoeping (Sweden); Allard, Bert; Hagberg, Jessica [Oerebro Univ., Oerebro (Sweden); Kaellstroem, Klas [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2012-09-15

    This report presents a literature review and laboratory work of the degradation of the fibre UP2, as well as an assessment of the effects of its degradation products on Europium sorption onto cement, as an example of their effects on radionuclide migration. All laboratory work was performed by the Swedish groups (Linkoeping and Oerebro Universities), who also performed some of the literature review. The data interpretation was performed by the Spanish team (Amphos 21). SKB has combined the reports of these studies into this common document and has added minor editorial changes. All these changes have been accepted by the authors.

  12. LC, MSn and LC-MS/MS studies for the characterization of degradation products of amlodipine

    Institute of Scientific and Technical Information of China (English)

    Ravi N. Tiwari; Nishit Shah; Vikas Bhalani; Anand Mahajan

    2015-01-01

    In the present study, comprehensive stress testing of amlodipine (AM) was carried out according to International Conference on Harmonization (ICH) Q1A(R2) guideline. AM was subjected to acidic, neutral and alkaline hydrolysis, oxidation, photolysis and thermal stress conditions. The drug showed instability in acidic and alkaline conditions, while it remained stable to neutral, oxidative, light and thermal stress. A total of nine degradation products (DPs) were formed from AM, which could be separated by the developed gradient LC method on a C18 column. The products formed under various stress conditions were investigated by LC–MS/MS analysis. The previously developed LC method was suitably modified for LC–MS/MS studies by replacing phosphate buffer with ammonium acetate buffer of the same concentration (pH 5.0). A complete fragmentation pathway of the drug was first established to characterize all the degradation products using LC–MS/MS and multi-stage mass (MSn) fragmentation studies. The obtained mass values were used to study elemental compositions, and the total information helped with the identification of DPs, along with its degradation pathway.

  13. LC, MSn and LC–MS/MS studies for the characterization of degradation products of amlodipine

    Directory of Open Access Journals (Sweden)

    Ravi N. Tiwari

    2015-02-01

    Full Text Available In the present study, comprehensive stress testing of amlodipine (AM was carried out according to International Conference on Harmonization (ICH Q1A(R2 guideline. AM was subjected to acidic, neutral and alkaline hydrolysis, oxidation, photolysis and thermal stress conditions. The drug showed instability in acidic and alkaline conditions, while it remained stable to neutral, oxidative, light and thermal stress. A total of nine degradation products (DPs were formed from AM, which could be separated by the developed gradient LC method on a C18 column. The products formed under various stress conditions were investigated by LC–MS/MS analysis. The previously developed LC method was suitably modified for LC–MS/MS studies by replacing phosphate buffer with ammonium acetate buffer of the same concentration (pH 5.0. A complete fragmentation pathway of the drug was first established to characterize all the degradation products using LC–MS/MS and multi-stage mass (MSn fragmentation studies. The obtained mass values were used to study elemental compositions, and the total information helped with the identification of DPs, along with its degradation pathway.

  14. Characterization of degradation products of idarubicin through LC-UV, MS(n) and LC-MS-TOF studies.

    Science.gov (United States)

    Kaushik, Dheeraj; Bansal, Gulshan

    2013-11-01

    Idarubicin was subjected to forced degradation under the ICH recommended conditions of hydrolysis, oxidation, dry heat and photolysis to characterize its possible impurities and/or degradation products. The drug was found unstable to acid hydrolysis at 85°C and to alkaline hydrolysis, and oxidation at room temperature. The hydrolytic and oxidative degradation products were resolved with gradient and isocratic elution, respectively on an Inertsil RP18 (250 mm × 4.6mm; 5 μ) column with HCOONH4 (20mM, pH 3.0) and acetonitrile. The drug degraded to two products (O-I and O-II) in oxidative condition, two products (K-I and K-II) in alkaline hydrolytic, and one product (A-I) in acidic hydrolytic conditions. The purity of each in the LC-UV chromatogram was ascertained through LC-PDA analysis. The products were characterized through +ESI-MS(n) studies on the drug and LC-MS-TOF studies on the degraded drug solutions. Based on the multistage mass fragmentation pattern of idarubicin and accurate mass analysis of the degradation products, the O-I, O-II and A-I were characterized as desacetylidarubicin hydroperoxide, desacetylidarubicin and deglucosaminylidarubicin, respectively. The products K-I and K-II were not characterized due to their low concentrations and/or extremely weak ionization. The mechanisms of degradation of idarubicin to these products were proposed and discussed.

  15. Maize production and land degradation: a Portuguese agriculture field case study

    Science.gov (United States)

    Ferreira, Carla S. S.; Pato, João V.; Moreira, Pedro M.; Valério, Luís M.; Guilherme, Rosa; Casau, Fernando J.; Santos, Daniela; Keizer, Jacob J.; Ferreira, António J. D.

    2016-04-01

    While food security is a main challenge faced by human kind, intensive agriculture often leads to soil degradation which then can threaten productivity. Maize is one of the most important crops across the world, with 869 million tons produced worldwide in 2012/2013 (IGC 2015), of which 929.5 thousand tons in Portugal (INE 2014). In Portugal, maize is sown in April/May and harvest occurs generally in October. Conventional maize production requires high inputs of water and fertilizers to achieve higher yields. As Portuguese farmers are typically rather old (on average, 63 years) and typically have a low education level (INE 2014), sustainability of their land management practises is often not a principal concern. This could explain why, in 2009, only 4% of the Portuguese temporary crops were under no-tillage, why only 8% of the farmers performed soil analyses in the previous three years, and why many soils have a low organic matter content (INE 2014). Nonetheless, sustainable land management practices are generally accepted to be the key to reducing agricultural soil degradation, preventing water pollution, and assuring long-term crop production objectives and food security. Sustainable land management should therefore not only be a concern for policy makers but also for farmers, since land degradation will have negative repercussions on the productivity, thus, on their economical income. This paper aims to assess the impact of maize production on soil properties. The study focusses on an 8 ha maize field located in central Portugal, with a Mediterranean climate on a gently sloping terrain (content, available phosphorous and potassium, exchangeable sodium, calcium, magnesium and potassium, as well as copper, zinc, iron and manganese).

  16. Identification of four new degradation products of epirubicin through forced degradation, LC-UV, MSn and LC-MS-TOF studies.

    Science.gov (United States)

    Kaushik, Dheeraj; Saini, Balraj; Bansal, Gulshan

    2015-01-01

    Epirubicin (EPI) was subjected to International Conference on Harmonization recommended forced degradation under the conditions of hydrolysis, oxidation, dry heat and photolysis to characterize its possible impurities and/or degradation products. The drug was found highly unstable to alkaline hydrolysis even at room temperature, unstable to acid hydrolysis at 80°C and to oxidation at room temperature. The hydrolytic and oxidative degradation products were resolved on an Agilent RP8 (150 mm × 4.6 mm; 5 µm) column with isocratic elution using mobile phase composed of ammonium formate (10 mM, pH 3.0), acetonitrile and methanol. The drug degraded to four oxidative products (O-I, O-II, O-III and O-IV) and to one acid hydrolyzed product (A-I). Purity of each peak in liquid chromatography-ultraviolet (LC-UV) chromatogram was ascertained through photodiode array (LC-PDA) analysis. The products were characterized through electrospray ionization-mass spectrometry (+ESI-MS(n)) studies on EPI and liquid chromatography-time of flight mass spectrometry (LC-MS-TOF) studies on degraded drug solutions. The products, O-I-O-IV, were characterized as 2-hydroxy-8-desacetylepirubicin-8-hydroperoxide, 4-hydroxy-8-desacetylepirubicin-8-hydroperoxide, 8-desacetylepirubicin-8-hydroperoxide and 8-desacetylepirubicin, respectively, and product A-I was characterized as deglucosaminylepirubicin. While A-I was found to be a pharmacopoeial impurity, all oxidative products were found to be new degradation impurities. The mechanisms and pathways of degradation of EPI were discussed and outlined.

  17. Degradation products from consumer nanocomposites: a case study on quantum dot lighting.

    Science.gov (United States)

    Liu, Jingyu; Katahara, John; Li, Guanglai; Coe-Sullivan, Seth; Hurt, Robert H

    2012-03-20

    Most nanomaterials enter the natural environment as nanoenabled products, which are typically composites with primary nanoparticles bound on substrates or embedded in liquid or solid matrices. The environmental risks associated with these products are expected to differ from those associated with the as-produced particles. This article presents a case study on the end-of-life emission of a commercial prototype polymer/quantum-dot (QD) composite used in solid-state lighting for homes. We report the extent of cadmium release upon exposure to a series of environmental and biological simulant fluids, and track the loss of QD-characteristic fluorescence as a marker for chemical damage to the CdSe/ZnS nanoparticles. Measured cadmium releases after 30-day exposure range from 0.007 to 1.2 mg/g of polymer, and the higher values arise for low-pH simulants containing nitric or gastric acid. Centrifugal ultrafiltration and ICP was used to distinguish soluble cadmium from particulate forms. The leachate is found to contain soluble metals with no evidence of free QDs or QD-containing polymeric debris. The absence of free nanoparticles suggests that this product does not raise nanotechnology-specific environmental issues associated with degradation and leaching, but is more usefully regarded as a conventional chemical product that is a potential source of small amounts of soluble cadmium.

  18. Characterization of stress degradation products of duloxetine hydrochloride employing LC-UV/PDA and LC-MS/TOF studies.

    Science.gov (United States)

    Chadha, Renu; Bali, Alka; Bansal, Gulshan

    2016-03-20

    Duloxetine HCl was subjected to forced degradation under conditions of hydrolysis (neutral, acidic and alkaline), oxidation, photolysis and thermal stress, as suggested in the ICH guideline Q1A(R2). The drug showed significant degradation under acidic, alkaline and aqueous hydrolytic as well as photolytic conditions. The drug remained stable under thermal and oxidative stress conditions. In total, seventeen degradation products (I-XVII) were formed under varied conditions, which could be separated by chromatography of respective degraded solutions on C18 (250 mm×4.6 mm; 5 μ, Nulceodur) column using isocratic elution method. Detection wavelength was selected as 290 nm. MS/TOF accurate mass studies were carried out to establish the complete fragmentation pathway of the drug and degradation products, which, in turn, was utilized in characterization of the products. The degradation pathway of the drug leading to generation of fifteen products I-X, XII-XIII, XV-XVII was postulated and this has not been reported so far.

  19. Oxidative degradation study on antimicrobial agent ciprofloxacin by electro-Fenton process: kinetics and oxidation products.

    Science.gov (United States)

    Yahya, Muna Sh; Oturan, Nihal; El Kacemi, Kacem; El Karbane, Miloud; Aravindakumar, C T; Oturan, Mehmet A

    2014-12-01

    Oxidative degradation of the antimicrobial agent ciprofloxacin hydrochloride (CIP) has been investigated using electro-Fenton (EF) treatment with a constant current in the range 60-500 mA. The process generates highly oxidant species OH in situ via electrochemically monitored Fenton reaction. The EF experiments were performed using cells with a carbon felt cathode and Pt anode. Effect of applied current and catalyst concentration on the kinetics of oxidative degradation and mineralization efficiency have been investigated. Degradation of CIP followed pseudo-first order reaction kinetics. The rate constant of the oxidation of CIP by OH has been determined to be (1.01 ± 0.14) × 10(10) M(-1) s(-1) by using competitive kinetics method. An optimum current of 400 mA and a catalyst concentration of Fe(2+) at 0.1mM are found to be optimal for an effective degradation of CIP under our operating conditions. A remarkably high degree of mineralization (>94%) was obtained at 6h of treatment under these conditions. A number of stable intermediate products have been identified using HPLC and LC-MS/MS analyses. Based on the identified reaction intermediates, a plausible reaction pathway was proposed for the mineralization process. The high degree of mineralization obtained in this work highlights the potential application of EF process in the efficient removal of fluoroquinolone based drugs in aqueous medium. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Studies on in vitro degradation and in vivo digestion of a slow ammonia releasing urea product.

    Science.gov (United States)

    Virk, A S; Steingass, H; Menke, K H

    1989-01-01

    a slow ammonia releasing urea product (Uromalt) has been produced by autoclaving and drying of germinated barley and urea. In vitro degradability of nitrogen (IVDN, Raab et al., 1983) was in average 62 +/- 9% in 4 hours, compared to 76 +/- 8% with an autoclaved and dried mixture of urea and not-germinated barley. Mixtures of urea with Leucaena l. or Azadarichta indica (Neem cake) showed degradabilities of about 80 and 93%, respectively, when dried at 39 degrees C, but of 65% when dried at 100 degrees C. For comparison, degradabilities of proteins of ground nut, guar, sunflower, mustard, rape and sesame cake/meal have been determined. When growing lambs were fed a ration containing 15% Uromalt, faecal N-excretion was significantly higher on the expense of urinary N-excretion, compared with groups fed isonitrogenous rations containing soya bean meal with or without urea and molasses. N-retention was not significantly affected. It is concluded that this slow ammonia releasing urea product can be used in cases where molasses or other feedingstuffs rich in rapidly fermentable carbohydrates are not available.

  1. Light Induced Degradation of Eight Commonly Used Pesticides Adsorbed on Atmospheric Particles: Kinetics and Product Study

    Science.gov (United States)

    Socorro, J.; Durand, A.; Gligorovski, S.; Wortham, H.; Quivet, E.

    2014-12-01

    Pesticides are widely used all over the world whether in agricultural production or in non-agricultural settings. They may pose a potential human health effects and environmental risks due to their physico-chemical properties and their extensive use which is growing every year. Pesticides are found in the atmosphere removed from the target area by volatilization or wind erosion, and carried over long distances. These compounds are partitioned between the gaseous and particulate atmospheric phases. The increasingly used pesticides are semi-volatile compounds which are usually adsorbed on the surface of the atmospheric particles. These pesticides may undergo chemical and photo-chemical transformation. New compounds may then be formed that could be more hazardous than the primary pesticides. The atmospheric fate and lifetime of adsorbed pesticides on particles are controlled by the these (photo)chemical processes. However, there is a lack of kinetic data regarding the pesticides in the particle phase. This current work focuses on the photolytic degradation of commonly used pesticides in particulate phase. It aims at estimating the photolytic rates and thus the lifetimes of pesticides adsorbed on silica particles as a proxy of atmospheric particles. The following eight commonly used pesticides, cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin, tetraconazole, were chosen because of their physico-chemical properties. The photolysis rates of tetraconazole and permethrin were extremely slow ≤ 1.2 · 10-6 s-1. The photolysis rates for the other pesticides were determined in the range of: (5.9 ± 0.3) · 10-6 fipronil. Finally, the identification of the surface products upon light irradiation was performed, using GC-(QqQ)-MS/MS and LC-(Q-IMS-ToF)-MS/MS. The potentially formed gas-phase products during these photolysis processes were followed continuously and on-line by PTR-ToF-MS. We hope that the obtained results from this study

  2. The Inhibitory Effect of Natural Products on Protein Fibrillation May Be Caused by Degradation Products – A Study Using Aloin and Insulin

    DEFF Research Database (Denmark)

    Lobbens, Eva Stephanie; Foderà, Vito; Nyberg, Nils

    2016-01-01

    is an as yet unidentified and potentially metastable degradation product of aloin. These results suggest that degradation products, and in particular oxidation products, are to be considered thoroughly when natural products are investigated for activity against protein fibrillation.......Protein fibrillation is the pathological hallmark of several neurodegenerative diseases and also complicates the manufacturing and use of protein drugs. As a case study, the inhibitory activity of the natural compound aloin against insulin fibrillation was investigated. Based on Thioflavin T assays......, high-performance liquid chromatography and transmission electron microscopy it was found that a degradation product of aloin, formed over weeks of storage, was able to significantly inhibit insulin fibrillation. The activity of the stored aloin was significantly reduced in the presence of small amounts...

  3. Occurrence and fate of alkylphenol polyethoxylate degradation products and linear alkylbenzene sulfonate surfactants in urban ground water: Barcelona case study

    Science.gov (United States)

    Tubau, Isabel; Vázquez-Suñé, Enric; Carrera, Jesús; González, Susana; Petrovic, Mira; López de Alda, María J.; Barceló, Damià

    2010-03-01

    SummaryThis study investigates the fate of alkylphenol polyethoxylates (APEOs) degradation products (DPs) and the occurrence of linear alkylbenzene sulfonate (LAS) surfactants in urban ground water at field scale. The occurrence of APEOs DPs in ground water was studied in connection with: (1) sources of recharge or/and pollution containing these substances, (2) ground water redox conditions, (3) occurrence of LAS, which are currently the domestic surfactants more used in the study area and (4) other common contaminants in urban ground water in the city of Barcelona. The APEOs DPs analyzed included two nonylphenol carboxylates (NP2EC, NP1EC), two octylphenol carboxylates (OP2EC, OP1EC), nonylphenol (NP) and octylphenol (OP). The highest groundwater concentrations of APEOs DPs were detected in aquifers whose major source of recharge is a river receiving large amounts of effluents from secondary waste water treatment plants (WWTPs). In fact, APEOs DPs concentrations were above those in the river. NP2EC was the compound detected at highest concentrations. These increase with ammonium in samples with low dissolved oxygen. These degradation products were virtually absent in oxidizing aquifers whose main source of recharge is not the river. In this case, only the ultimate degradation product (NP) was detected, which suggests that parent compounds have degraded. These results indicate that APEOs are persistent or less degraded in reducing conditions, whereas they are degraded when oxidizing conditions prevail. By contrast, LAS concentrations were more than one order of magnitude lower than expected based on recharge sources in all (oxidizing and reducing) aquifers.

  4. Acidic hydrolysis of bromazepam studied by high performance liquid chromatography. Isolation and identification of its degradation products.

    Science.gov (United States)

    Panderi, I; Archontaki, H; Gikas, E; Parissi-Poulou, M

    1998-06-01

    A kinetic study on the acidic hydrolysis of bromazepam was carried out in 0.01 M hydrochloric acid solution at 25 and 95 degrees C. A reversed-phase HPLC method was developed and validated for the determination of bromazepam and its degradation products. Bromazepam degraded by a consecutive reaction with a reversible first step. Two degradation products were isolated and identified by infrared, 1H and 13C nuclear magnetic resonance and mass spectroscopy. Spectroscopic data indicated that N-(4-bromo-2-(2-pyridylcarbonyl)phenyl)-2-aminoacetamide was the intermediate degradation product of this acid hydrolysis, whereas 2-amino-5-bromophenyl-2-pyridylmethanone was the final one. Therefore, the mechanism of this acid-catalysed hydrolysis involved initial cleavage of the 4,5-azomethine bond, followed by slow breakage of the 1,2-amide bond. Statistical evaluation of the HPLC method revealed its good linearity and reproducibility. Detection limits were 3.8 x 10(-7) M for bromazepam, 6.25 x 10(-7) M for the intermediate and 8.16 x 10(-7) M for the benzophenone derivative.

  5. The Inhibitory Effect of Natural Products on Protein Fibrillation May Be Caused by Degradation Products--A Study Using Aloin and Insulin.

    Directory of Open Access Journals (Sweden)

    Eva S Lobbens

    Full Text Available Protein fibrillation is the pathological hallmark of several neurodegenerative diseases and also complicates the manufacturing and use of protein drugs. As a case study, the inhibitory activity of the natural compound aloin against insulin fibrillation was investigated. Based on Thioflavin T assays, high-performance liquid chromatography and transmission electron microscopy it was found that a degradation product of aloin, formed over weeks of storage, was able to significantly inhibit insulin fibrillation. The activity of the stored aloin was significantly reduced in the presence of small amounts of sodium azide or ascorbic acid, suggesting the active compound to be an oxidation product. A high-performance liquid chromatography method and a liquid chromatography-mass spectrometry method were developed to investigate the degradation products in the aged aloin solution. We found that the major compounds in the solution were aloin A and aloin B. In addition, 10-hydroxy aloin and elgonica dimers were detected in smaller amounts. The identified compounds were isolated and tested for activity by means of Thioflavin T assays, but no activity was observed. Thus, the actual fibrillation inhibitor is an as yet unidentified and potentially metastable degradation product of aloin. These results suggest that degradation products, and in particular oxidation products, are to be considered thoroughly when natural products are investigated for activity against protein fibrillation.

  6. Structural elucidation of gemifloxacin mesylate degradation product.

    Science.gov (United States)

    Paim, Clésio Soldateli; Führ, Fernanda; Martins, Magda Targa; Gnoatto, Simone; Bajerski, Lisiane; Garcia, Cássia Virginia; Steppe, Martin; Schapoval, Elfrides Eva Scherman

    2016-03-01

    Gemifloxacin mesylate (GFM), chemically (R,S)-7-[(4Z)-3-(aminomethyl)-4-(methoxyimino)-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid methanesulfonate, is a synthetic broad-spectrum antibacterial agent. Although many papers have been published in the literature describing the stability of fluorquinolones, little is known about the degradation products of GFM. Forced degradation studies of GFM were performed using radiation (UV-A), acid (1 mol L(-1) HCl) and alkaline conditions (0.2 mol L(-1) NaOH). The main degradation product, formed under alkaline conditions, was isolated using semi-preparative LC and structurally elucidated by nuclear magnetic resonance (proton - (1) H; carbon - (13) C; correlate spectroscopy - COSY; heteronuclear single quantum coherence - HSQC; heteronuclear multiple-bond correlation - HMBC; spectroscopy - infrared, atomic emission and mass spectrometry techniques). The degradation product isolated was characterized as sodium 7-amino-1-pyrrolidinyl-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate, which was formed by loss of the 3-(aminomethyl)-4-(methoxyimino)-1-pyrrolidinyl ring and formation of the sodium carboxylate. The structural characterization of the degradation product was very important to understand the degradation mechanism of the GFM under alkaline conditions. In addition, the results highlight the importance of appropriate protection against hydrolysis and UV radiation during the drug-development process, storage, handling and quality control.

  7. Development and validation of a stability-indicating LC-UV method for the determination of pantethine and its degradation product based on a forced degradation study.

    Science.gov (United States)

    Canavesi, Rossana; Aprile, Silvio; Varese, Elena; Grosa, Giorgio

    2014-08-01

    Pantethine (d-bis-(N-pantothenyl-β-aminoethyl)-disulfide, PAN), the stable disulfide form of pantetheine, has beneficial effects in vascular diseases being able to decrease the hyperlipidaemia, moderate the platelet function and prevent the lipid peroxidation. Furthermore, recent studies suggested that PAN may be an effective therapeutic agent for cerebral malaria and, possibly, for neurodegenerative processes. Interestingly, in the literature, there were no data dealing with the chemical stability and the analytical aspects of PAN. Hence, in the present work the chemical stability of PAN was for the first time established through a forced degradation study followed by liquid chromatography tandem mass spectrometry investigation showing the formation of three degradation products of PAN (PD1, PD2 and POx) arising from hydrolytic, thermal and oxidative stresses. Based on these data a stability-indicating LC-UV method for simultaneous estimation of PAN, and its most relevant degradation product (PD1) was developed and validated; moreover the method allowed also the separation and the quantification of the preservative system, constituted by a paraben mixture. The method showed linearity for PAN (0.4-1.2mgmL(-1)), MHB, PHB (0.4-1.2μgmL(-1)) and PD1 (2.5-100μgmL(-1)); the precision, determined in terms of intra-day and inter-day precision, expressed as RSDs, were in the ranges 0.4-1.2 and 0.7-1.4, respectively. The method demonstrated to be accurate and robust; indeed the average recoveries were 100.2, 99.9, and 100.0% for PAN, MHB and PHB, respectively, and 99.9% for PD1. By applying small variations of the mobile phase composition, counter-ion concentration and pH the separation of analytes was not affected. Finally, the applicability of this method was evaluated analyzing the available commercial forms at release as well as during stability studies.

  8. Environmental Fate of the Herbicide Fluazifop-P-butyl and Its Degradation Products in Two Loamy Agricultural Soils: A Combined Laboratory and Field Study.

    Science.gov (United States)

    Badawi, Nora; Rosenbom, Annette E; Olsen, Preben; Sørensen, Sebastian R

    2015-08-01

    The herbicide fluazifop-P-butyl (FPB) is used against grasses in agricultural crops such as potato, oilseed rape, and sugar beet. Limited information is available in scientific literature on its environmental fate, therefore extensive monitoring at two agricultural test fields was combined with laboratory studies to determine leaching and the underlying degradation and sorption processes. Water samples from drains, suction cups, and groundwater wells showed leaching of the degradation products fluazifop-P (FP) and 2-hydroxy-5-trifluoromethyl-pyridin (TFMP) following FPB treatment. Laboratory experiments with soil from each field revealed a rapid degradation of FPB to FP. The degradation was almost exclusively microbial, and further biodegradation to TFMP occurred at a slower rate. Both degradation products were sorbed to the two soils to a small extent and were fairly persistent to degradation during the two-month incubation period. Together, the field and laboratory results from this study showed that the biodegradation of FPB in loamy soils gave rise to the production of two major degradation products that sorbed to a small extent. In this study, both degradation products leached to drainage and groundwater during precipitation. It is therefore recommended that these degradation products be included in programs monitoring water quality in areas with FPB use.

  9. A STUDY ON THE DEGRADATION MECHANISM OF PHOTOCROSSLINKING PRODUCTS FORMED BY CYCLIZED POLYISOPRENE-DIAZIDE SYSTEM UNDER THE INFLUENCE OF ALKYL BENZENE SULFONIC ACIDS

    Institute of Scientific and Technical Information of China (English)

    HUANG Junlian; SUN Meng

    1989-01-01

    The degradation mechanism of photocrosslinking products formed by cyclized polyisoprene-diazide system under the influence of the different alkyl benzene sulfonic acids was studied. The effects ofalkyl chain length and the concentration of alkyl benzene sulfonic acids on the rate of degradation reaction were discussed. It was found that in the initial stage of degradation, the cyclicity ratio and the average fused ring number did not change considerably, but the percentage of uncyclized parts content varied significantly. The suitable mechanism was supposed.

  10. Environmental Fate of the Herbicide Fluazifop-P-butyl and Its Degradation Products in Two Loamy Agricultural Soils: A Combined Laboratory and Field Study

    DEFF Research Database (Denmark)

    Badawi, Nora; Rosenbom, Anette E.; Olsen, Preben;

    2015-01-01

    The herbicide fluazifop-P-butyl (FPB) is used against grasses in agricultural crops such as potato, oilseed rape and sugar beet. Limited information is available in Scientific literature on its environmental fate, therefore extensive monitoring at two agricultural test fields was combined...... with laboratory studies to determine leaching and the underlying degradation and sorption processes. Water samples from drains, suction cups, and groundwater wells showed leaching of the degradation products fluazifop-P (FP) and 2- hydroxy-5-trifluoromethyl-pyridin (TFMP) following FPB treatment. Laboratory...... experiments with soil from each field revealed a rapid degradation of FPB to FP. The degradation was almost exclusively microbial, and further biodegradation to TFMP occurred at a slower rate. Both degradation products were sorbed to the two soils to a small extent and were fairly persistent to degradation...

  11. [Studies on lignocellulolytic enzymes production and biomass degradation of Pleurotus sp2 and Trametes gallica in wheat straw cultures].

    Science.gov (United States)

    Xie, J; Sun, X; Ren, L; Zhang, Y Z

    2001-09-01

    Pleurotus sp2 and Trametes gallica were selected in this assay because of their high activities of lignocellulolytic enzymes and the enzyme peaks appeared at the early stage of liquid state fermentation. Solid state fermentation was also investigated for their abilities and behaviors of enzyme-production. The capabilities and characteristics of the two strains in degrading biomass were studied. When Pleurotus sp2 was incubated in wheat straw powder containing the liquid medium of low-nitrogen, no-carbon and high inorganic salt, the activities of MnP and Lac reached the peaks on the tenth day, but the activities of hemicellulases reached the peak on the 40th day. Pleurotus sp2 caused 17.6% of biomass loss. When T. gallica was incubated in wheat straw powder containing the liquid medium of hlig-nitrogen, or low-nitrogen, no-carbon and high inorganic salt, the activities of MnP reached the peaks on the tenth day, the lac and hemicelluloses on the 40th day, and the lignin peroxidases reached the peaks on the 50th day, and it caused more than 64% of biomass loss. Among them the hemicellulose was degraded by 71.96%, and the cellulose 66.21%. T. gallica was very capable of degrading lignin of wheat straw and caused 34.37% loss during 20 days, 46. 71% loss during 30 days and 70.14% loss during 60 days. It was interesting that T. gallica degraded lignin preferentially with respect to cellulose, which was very beneficial to biopulping of paper industry.

  12. Continuous flow stable isotope methods for study of δ13C fractionation during halomethane production and degradation

    Science.gov (United States)

    Kalin, Robert M.; Hamilton, John T.G.; Harper, David B.; Miller, Laurence G.; Lamb, Clare; Kennedy, James T.; Downey, Angela; McCauley, Sean; Goldstein, Allen H.

    2001-01-01

    Gas chromatography/mass spectrometry/isotope ratio mass spectrometry (GC/MS/IRMS) methods for δ13C measurement of the halomethanes CH3Cl, CH3Br, CH3I and methanethiol (CH3SH) during studies of their biological production, biological degradation, and abiotic reactions are presented. Optimisation of gas chromatographic parameters allowed the identification and quantification of CO2, O2, CH3Cl, CH3Br, CH3I and CH3SH from a single sample, and also the concurrent measurement of δ13C for each of the halomethanes and methanethiol. Precision of δ13C measurements for halomethane standards decreased (±0.3, ±0.5 and ±1.3‰) with increasing mass (CH3Cl, CH3Br, CH3I, respectively). Given that carbon isotope effects during biological production, biological degradation and some chemical (abiotic) reactions can be as much as 100‰, stable isotope analysis offers a precise method to study the global sources and sinks of these halogenated compounds that are of considerable importance to our understanding of stratospheric ozone destruction. 

  13. OH-radical induced degradation of hydroxybenzoic- and hydroxycinnamic acids and formation of aromatic products-A gamma radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Krimmel, Birgit; Swoboda, Friederike [University of Vienna, Department of Nutritional Sciences, Section Radiation Biology (Austria); Solar, Sonja, E-mail: sonja.solar@univie.ac.a [University of Vienna, Department of Nutritional Sciences, Section Radiation Biology (Austria); Reznicek, Gottfried [Department of Pharmacognosy, Althanstrasse 14, A-1090 Vienna (Austria)

    2010-12-15

    The OH-radical induced degradation of hydroxybenzoic acids (HBA), hydroxycinnamic acids (HCiA) and methoxylated derivatives, as well as of chlorogenic acid and rosmarinic acid was studied by gamma radiolysis in aerated aqueous solutions. Primary aromatic products resulting from an OH-radical attachment to the ring (hydroxylation), to the position occupied by the methoxyl group (replacement -OCH{sub 3} by -OH) as well as to the propenoic acid side chain of the cinnamic acids (benzaldehyde formations) were analysed by HPLC-UV and LC-ESI-MS. A comparison of the extent of these processes is given for 3,4-dihydroxybenzoic acid, vanillic acid, isovanillic acid, syringic acid, cinnamic acid, 4-hydroxycinnamic acid, caffeic acid, ferulic acid, isoferulic acid, chlorogenic acid, and rosmarinic acid. For all cinnamic acids and derivatives benzaldehydes were significant oxidation products. With the release of caffeic acid from chlorogenic acid the cleavage of a phenolic glycoside could be demonstrated. Reaction mechanisms are discussed.

  14. Study of the forced degradation behavior of prasugrel hydrochloride by liquid chromatography with mass spectrometry and liquid chromatography with NMR detection and prediction of the toxicity of the characterized degradation products.

    Science.gov (United States)

    Singh, Dilip Kumar; Sahu, Archana; Handa, Tarun; Narayanam, Mallikarjun; Singh, Saranjit

    2015-09-01

    Prasugrel was subjected to forced degradation studies under conditions of hydrolysis (acid, base, and neutral), photolysis, oxidation, and thermal stress. The drug showed liability in hydrolytic as well as oxidative conditions, resulting in a total of four degradation products. In order to characterize the latter, initially mass fragmentation pathway of the drug was established with the help of mass spectrometry/time-of-flight, multiple stage mass spectrometry and hydrogen/deuterium exchange data. The degradation products were then separated on a C18 column using a stability-indicating volatile buffer method, which was later extended to liquid chromatography-mass spectrometry studies. The latter highlighted that three degradation products had the same molecular mass, while one was different. To characterize all, their mass fragmentation pathways were established in the same manner as the drug. Subsequently, liquid chromatography-nuclear magnetic resonance (NMR) spectroscopy data were collected. Proton and correlation liquid chromatography with NMR spectroscopy studies highlighted existence of diastereomeric behavior in one pair of degradation products. Lastly, toxicity prediction by computer-assisted technology (TOPKAT) and deductive estimation of risk from existing knowledge (DEREK) software were employed to assess in silico toxicity of the characterized degradation products.

  15. Stress degradation study and structure characterization of oxidation degradation product of dexlansoprazole using liquid chromatography-mass spectrometry/time of flight, liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance

    Institute of Scientific and Technical Information of China (English)

    Lakkireddy PRAKASH; M HIMAJA

    2016-01-01

    The present study deals with the forced degradation behavior of dexlansoprazole under International Conference on Harmonisation( ICH)prescribed stress conditions. The drug was found to be more labile under acid,base,neutral,oxidative hydrolysis and thermal stress,while it was moderately stable under photolytic conditions. The known and unknown degradation products were separated on a C-18 column using a stability-indicating method. Liquid chromatography-mass spectrometry( LC-MS)analysis was performed for all the deg-radation studies. Isolation and structure characterization of oxidation degradation products were executed using sophisticated tools,viz. preparative high performance liquid chromatography( HPLC),liquid chromatography-mass spectrometry/time of flight( LC-MS/TOF),liquid chromatography-tandem mass spectrometry( LC-MS/MS),and nuclear magnetic resonance( NMR). This study demonstrates an ample methodology of degradation studies and structure elucidation of unknown degradation products of dexlansoprazole,which helps in the development and stability study of active pharmaceutical ingredients and formulated products.

  16. Oxidative degradation of triazine- and sulfonylurea-based herbicides using Fe(VI): The case study of atrazine and iodosulfuron with kinetics and degradation products

    Science.gov (United States)

    The occurrence of common herbicides (Atrazine, ATZ and Iodosufuron, IDS), in waters presents potential risk to human and ecological health. The oxidative degradation of ATZ and IDS by ferrate(VI) (FeVIO42-, Fe(VI)) is studied at different pH levels where kinetically observed se...

  17. Oxidative degradation of triazine- and sulfonylurea-based herbicides using Fe(VI): The case study of atrazine and iodosulfuron with kinetics and degradation products

    Science.gov (United States)

    The occurrence of common herbicides (Atrazine, ATZ and Iodosufuron, IDS), in waters presents potential risk to human and ecological health. The oxidative degradation of ATZ and IDS by ferrate(VI) (FeVIO42-, Fe(VI)) is studied at different pH levels where kinetically observed se...

  18. Advice on Degradation Products in Pharmaceuticals: A Toxicological Evaluation.

    Science.gov (United States)

    Melo, Sâmia Rocha de Oliveira; Homem-de-Mello, Maurício; Silveira, Dâmaris; Simeoni, Luiz Alberto

    Degradation products are unwanted chemicals that can develop during the manufacturing, transportation, and storage of drug products and can affect the efficacy of pharmaceutical products. Moreover, even small amounts of degradation products can affect pharmaceutical safety because of the potential to cause adverse effects in patients. Consequently, it is crucial to focus on mechanistic understanding, formulation, storage conditions, and packaging to prevent the formation of degradation products that can negatively affect the quality and safety of the drug product. In this sense, databases and software that help predict the reactions involving the pharmaceutically active substance in the presence of degradation conditions can be used to obtain information on major degradation routes and the main degradation products formed during pharmaceutical product storage. In some cases, when the presence of a genotoxic degradation product is verified, it is necessary to conduct more thorough assessments. It is important to consider the chemical structure to distinguish between compounds with toxicologically alerting structures with associated toxic/genotoxic risks and compounds without active structures that can be treated as ordinary impurities. Evaluating the levels of degradation products based on a risk/benefit analysis is mandatory. Controlling critical variables during early development of drug products and conducting a follow-up study of these impurities can prevent degradation impurities present at concentrations greater than threshold values to ensure product quality. The definition of the impurity profile has become essential per various regulatory requirements. Therefore, this review includes the international regulatory perspective on impurity documents and the toxicological evaluation of degradation products. Additionally, some techniquesused in the investigation of degradation products and stability-indicating assay methods are highlighted.

  19. Photothermal degradation studies

    Science.gov (United States)

    Liang, R. H.

    1985-01-01

    Key reaction intermediates of photooxidation identified and characterized by laser flash Electron Spin Resonance (ESR) spectroscopy were discussed. Effects of temperature and ultraviolet intensity were studied in order to develop meaningful accelerated testing procedures for encapsulant evaluation. In a program to study the failure of Tedlar/ethylene vinyl acetate (EVA)/stainless steel modules, failure modes similar to those observed outdoors in real-time conditions were simulated in accelerated testing. An experimental technique was developed to quantitatively assess the extent of degradation.

  20. Determination of impurities and degradation products from veterinary medicinal products by HPLC method

    Directory of Open Access Journals (Sweden)

    Elena Gabriela Oltean

    2014-06-01

    Full Text Available The organic or inorganic impurities in the veterinary medicinal product can derive from starting materials, manufacturing process, incomplete purification, inappropriate storage. The acceptable levels of impurities in pharmaceuticals are estimated by comparison with standard solutions, according to the appropriate monographs. Forced degradation studies determine the stability of the method of dosage for the active compounds and for the entire finished product under excessive accelerated degradation conditions. They also provide information on degradation pathways and selectivity of analytical methods applied. The information provided by the degradation studies on the active compound and finished pharmaceutical product should demonstrate the specificity of the analytical method regarding impurities. Forced degradation studies should demonstrate that the impurities and degradation products generated do not interfere with the active compound. The current forced degradation methods consist of acid hydrolysis, basic hydrolysis, oxidation, exposure of the medicinal product to temperature and light. HPLC methods are an integral analytical instrument for the analysis of the medicinal product. The HPLC method should be able to separate, detect and quantify various specific degradation products that can appear after manufacture or storage of the medicinal product, as well as new elements appearing after synthesis. FDA and ICH guidelines recommend the enclosure of the results, including the chromatograms specific to the forced degradation-subjected medicinal product, in the documentation for marketing authorization. Using HPLC methods in forced degradation studies on medicinal products provides relevant information on the method of determination for the formulation of the medicinal product, synthesis product, packaging methods and storage.

  1. Fibrin and fibrinogen degradation products in plasma : clinical and methodological studies using enzyme immuno assays

    NARCIS (Netherlands)

    H. Kroneman (Herman)

    1992-01-01

    textabstractThis thesis comprises studies with monoclonal antibody-based plasma assays for derivatives of fibrin and fibrinogen in patients with diseases and conditions characterized by an activated state of coagulation and fibrinolysis

  2. LC and LC–MS study for simultaneous determination of tramadol hydrochloride and ketorolac tromethamine in bulk and formulation with their major degradation products

    Directory of Open Access Journals (Sweden)

    Vrushali S. Tambe

    2016-06-01

    From the mass spectral data, probable structures were assigned to the degradation products. The identified major degradation product for tramadol under acid stress may be 1-(3′-methoxy-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl-N,N-dimethylmethanamine. Ketorolac tromethamine was also found to convert in to numerous degradation products under oxidative stress.

  3. Research of the degradation products of chitosan's angiogenic function

    Science.gov (United States)

    Wang, Jianyun; Chen, Yuanwei; Ding, Yulong; Shi, Guoqi; Wan, Changxiu

    2008-11-01

    Angiogenesis is of great importance in tissue engineering and has gained large attention in the past decade. But how it will be influenced by the biodegradable materials, especially their degradation products, remains unknown. Chitosan (CS) is a kind of naturally occurred polysaccharide which can be degraded in physiological environment. In order to gain some knowledge of the influences of CS degradation products on angiogenesis, the interaction of vascular endothelial cells with the degradation products was investigated in the present study. The CS degradation products were prepared by keeping CS sample in physiological saline aseptically at 37 °C for 120 days. Endothelial cells were co-cultured with the degradation products and the angiogenic cell behaviors, including cell proliferation, migration and tube-like structure (TLS) formation, were tested by MTT assay, cell migration quantification method (CMQM), and tube-like structure quantification method (TLSQM) respectively. Furthermore, mRNA expressions of vascular endothelial growth factor (VEGF) and matrix metallo proteinase (MMP-2) were determined by real-time reverse transcriptional polymerase chain reaction (RT-PCR). Physiological saline served as a negative control. As the results showed, the degradation products obtained from 20th to 60th day significantly inhibited the proliferation, migration, and TLS formation of endothelial cells. However, degradation products of the first 14 days and the last 30 days were found to be proangiogenic. At the molecular level, the initial results indicated that the mRNA expressions of VEGF and MMP-2 were increased by the degradation products of 7th day, but were decreased by the ones of 60th day. According to all the results, it could be concluded that the angiogenic behaviors of endothelial cells at both cellular and molecular level could be significantly stimulated or suppressed by the degradation products of CS and the influences are quite time-dependent.

  4. Kinetic study and mechanism of Niclosamide degradation

    Science.gov (United States)

    Zaazaa, Hala E.; Abdelrahman, Maha M.; Ali, Nouruddin W.; Magdy, Maimana A.; Abdelkawy, M.

    2014-11-01

    A spectrophotometric kinetic study of Niclosamide alkaline degradation as a function of drug concentration, alkaline concentration and temperature has been established utilizing double divisor-ratio spectra spectrophotometric method. The developed method allowed determination of Niclosamide in presence of its alkaline degradation products; namely; 2-chloro-4-nitro aniline (DEG I) and 5-chloro salicylic acid (DEG II) with characterization of its degradation mechanism. It was found that degradation kinetic of Niclosamide followed pseudo-first order under the established experimental conditions with a degradation rate constant (k) of 0.0829 mol/h and half life (t1/2) of 8.35 h. The overall degradation rate constant as a function of the temperature under the given conditions obeyed Arrhenius equation where the activation energy was calculated to be 3.41 kcal/mol.

  5. Derivative spectrophotometry for the determination of faropenem in the presence of degradation products: an application for kinetic studies.

    Science.gov (United States)

    Cielecka-Piontek, Judyta

    2013-07-01

    A simple and selective derivative spectrophotometric method was developed for the quantitative determination of faropenem in pure form and in pharmaceutical dosage. The method is based on the zero-crossing effect of first-derivative spectrophotometry (λ = 324 nm), which eliminates the overlapping effect caused by the excipients present in the pharmaceutical preparation, as well as degradation products, formed during hydrolysis, oxidation, photolysis, and thermolysis. The method was linear in the concentration range 2.5-300 μg/mL (r = 0.9989) at λ = 341 nm; the limits of detection and quantitation were 0.16 and 0.46 μg/mL, respectively. The method had good precision (relative standard deviation from 0.68 to 2.13%). Recovery of faropenem ranged from 97.9 to 101.3%. The first-order rate constants of the degradation of faropenem in pure form and in pharmaceutical dosage were determined by using first-derivative spectrophotometry. A statistical comparison of the validation results and the observed rate constants for faropenem degradation with these obtained with the high-performance liquid chromatography method demonstrated that both were compatible.

  6. Study on Antioxidant Activity of Catalyzed Hydrogen Degradation Product of Polymeric Proanthocyanidins (LPPC from Larix gmelinii Bark

    Directory of Open Access Journals (Sweden)

    Gui-quan Jiang

    2013-12-01

    Full Text Available A grading countercurrent extraction method was used to separate polymeric proanthocyanidins (LPPC from degreased Larix gmelinii bark, and the purification of LPPC was performed using HP-2MGL resin. The purity of LPPC was 26.37%. The cumulative recovery rate of purified product (LPPC-1 was 98.54% by the adsorption method of HP-2MGL resin. The purity of LPPC-1 was 99.79%. Catalytic hydrogenolysis tests of LPPC-1 were performed by means of a palladium carbon catalyst. The degradation rate was 67.5%, and the residual rate was 72.1%. The results of antioxidant ability showed that the degradation product (LHOPC had more excellent antioxidant ability compared with LPPC-1, VC, TBHQ, grape seed extract, and pine bark extract. The results, through the analysis of the linear model of MALDI-TOF/TOF MS, revealed that LHOPC was oligomeric with the tetramer as the major component and the distribution ranging from the trimer to eleven units.

  7. Determination of lumiracoxib by a validated stability-indicating MEKC method and identification of its degradation products by LC-ESI-MS studies.

    Science.gov (United States)

    Sangoi, Maximiliano S; Wrasse-Sangoi, Micheli; Oliveira, Paulo R; Bernardi, Larissa S

    2011-08-01

    A stability-indicating MEKC method was developed and validated for the analysis of lumiracoxib (LMC) in pharmaceutical formulations using nimesulide as the internal standard (IS). Optimal conditions for the separation of LMC and degradation products were investigated. The method employed 50 mM borate buffer and 50 mM anionic detergent SDS solution at pH 9.0. MEKC method was performed on a fused-silica capillary (50 μm id; effective length, 40 cm) maintained at 30°C. The applied voltage was 20 kV and photodiode array (PDA) detector was set at 208 nm. The method was validated in accordance with the International Conference on Harmonisation requirements. The stability-indicating capability of the method was established by enforced degradation studies combined with peak purity assessment using PDA detection. The degradation products formed under stressed conditions were investigated by LC-ESI-MS and the two degraded products were identified. MEKC method was linear over the concentration range of 5-150 μg/mL (r(2) =0.9999) of LMC. The method was precise, accurate, with LOD and LOQ of 1.34 and 4.48 μg/mL, respectively. The robustness was proved by a fractional factorial design evaluation. The proposed MEKC method was successfully applied for the quantitative analysis of LMC in tablets to support the quality control.

  8. ESI-MSn and LC-ESI-MS studies to characterize forced degradation products of bosentan and a validated stability-indicating LC-UV method.

    Science.gov (United States)

    Bansal, Gulshan; Singh, Ranjit; Saini, Balraj; Bansal, Yogita

    2013-01-01

    The present study reports the characterization of forced degradation products of bosentan and a validated stability-indicating HPLC method for the stability testing of bosentan tablets. The forced degradation was carried out under the conditions of hydrolysis, oxidation, dry heat and photolysis. The drug was found unstable in acid, alkali and oxidative media whereas stable to the hydrolysis in water, to dry heat and to photolysis. In total, six degradation products were formed in all conditions which were resolved in a single run on a C-18 column with gradient elution using ammonium acetate buffer (pH 4.5, 5.0mM), methanol and acetonitrile. Structures of all the degradation products were characterized through +ESI-MS(n) and LC-ESI-MS spectral data of bosentan as well as LC-ESI-MS spectral data of the products. The products II-VI were characterized as 6-amino-[2,2']bipyrimidinyl-4,5-diol, 6-amino-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-ol, 2-[6-amino-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-yloxy]-ethanol, 4-tert-butyl-N-[6-(1-methoxyethoxy)-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-yl]-benzenesulfonamide and 4-tert-butyl-N-[6-hydroxy-5-(2-methoxyphenoxy)-[2,2']bipyrimidinyl-4-yl]-benzenesulfonamide, respectively. The peak of the product I was found to be due to two secondary degradation products which co-eluted and were characterized as β-hydroxyethyl p-tert-butylphenylsulfonate (Ia) and 2-[2-(2-hydroxyethoxy)-phenoxy]-ethanol (Ib). These products were formed due to hydrolysis of sulfonamide and alkylaryl ether and the diaryl ether linkages as well as dehydration of the primary alcohol group. The most probable degradation mechanisms were proposed. The HPLC method was found to be stability-indicating, linear (2-100 μg ml(-1)), accurate, precise, sensitive, specific, rugged and robust for quantitation of the drug. The method was applied to the stability testing of the commercially available bosentan tablets successfully.

  9. Degradation kinetics and products of triazophos in intertidal sediment

    Institute of Scientific and Technical Information of China (English)

    LIN Kun-de; YUAN Dong-xing

    2005-01-01

    This work presents laboratory studies on the degradation of triazophos in intertidal sediment. The overall degradations were found to follow the first-order decay model. After being incubated for 6 d, the percentage of degradations of triazophos in unsterilized and sterilized sediments were 94.5% and 20.5%, respectively. Between the temperatures of 15℃ and 35℃, the observed degradation rate constant( kobsd ) enhanced as the incubation temperature increased. Triazophos in sediment degraded faster under aerobic condition than under anaerobic one. The water content of sediment had little influence on the degradation when it was in the range of 50%-100%. The values of kobsd decreased with increasing initial concentration of triazophos in sediment, which could result from the microorganism inhibition by triazophos. Four major degradation products, o, o-diethyl phosphorothioic acid, monoethyl phosphorothioic acid, phosphorothioic acid,and 1-phenyl-3-hydroxy-1,2,4-triazole, were tentatively identified as their corresponding trimethylsilyl derivatives with a gas chromatography-mass spectrometer. The possible degradation pathway of triazophos in intertidal sediment was proposed. The results revealed that triazophos in intertidal sediment was relatively unstable and could be easily degraded.

  10. High Modulus Biodegradable Polyurethanes for Vascular Stents: Evaluation of Accelerated in vitro Degradation and Cell Viability of Degradation Products.

    Science.gov (United States)

    Sgarioto, Melissa; Adhikari, Raju; Gunatillake, Pathiraja A; Moore, Tim; Patterson, John; Nagel, Marie-Danielle; Malherbe, François

    2015-01-01

    We have recently reported the mechanical properties and hydrolytic degradation behavior of a series of NovoSorb™ biodegradable polyurethanes (PUs) prepared by varying the hard segment (HS) weight percentage from 60 to 100. In this study, the in vitro degradation behavior of these PUs with and without extracellular matrix (ECM) coating was investigated under accelerated hydrolytic degradation (phosphate buffer saline; PBS/70°C) conditions. The mass loss at different time intervals and the effect of aqueous degradation products on the viability and growth of human umbilical vein endothelial cells (HUVEC) were examined. The results showed that PUs with HS 80% and below completely disintegrated leaving no visual polymer residue at 18 weeks and the degradation medium turned acidic due to the accumulation of products from the soft segment (SS) degradation. As expected the PU with the lowest HS was the fastest to degrade. The accumulated degradation products, when tested undiluted, showed viability of about 40% for HUVEC cells. However, the viability was over 80% when the solution was diluted to 50% and below. The growth of HUVEC cells is similar to but not identical to that observed with tissue culture polystyrene standard (TCPS). The results from this in vitro study suggested that the PUs in the series degraded primarily due to the SS degradation and the cell viability of the accumulated acidic degradation products showed poor viability to HUVEC cells when tested undiluted, however particles released to the degradation medium showed cell viability over 80%.

  11. Liquid chromatography and liquid chromatography-mass spectrometry analysis of donepezil degradation products

    Directory of Open Access Journals (Sweden)

    Mladenović Aleksandar R.

    2015-01-01

    Full Text Available This study describes the investigation of degradation products of donepezil (DP using stability indicating RP-HPLC method for determination of donepezil, which is a centrally acting reversible acetylcholinesterase inhibitor. In order to investigate the stability of drug and formed degradation products, a forced degradation study of drug sample and finished product under different forced degradation conditions has been conducted. Donepezil hydrochloride and donepezil tablets were subjected to stress degradation conditions recommended by International Conference on Harmonization (ICH. Donepezil hydrochloride solutions were subjected to acid and alkali hydrolysis, chemical oxidation and thermal degradation. Significant degradation was observed under alkali hydrolysis and oxidative degradation conditions. Additional degradation products were observed under the conditions of oxidative degradation. The degradation products observed during forced degradation studies were monitored using the high performance liquid chromatography (HPLC method developed. The parent method was modified in order to obtain LC-MS compatible method which was used to identify the degradation products from forced degradation samples using high resolution mass spectrometry. The mass spectrum provided the precise mass from which derived molecular formula of drug substance and degradation products formed and proved the specificity of the method unambiguously. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  12. Critical practical aspects in the application of liquid chromatography-mass spectrometric studies for the characterization of impurities and degradation products.

    Science.gov (United States)

    Narayanam, Mallikarjun; Handa, Tarun; Sharma, Parul; Jhajra, Shalu; Muthe, Praveen Kumar; Dappili, Pavan Kumar; Shah, Ravi P; Singh, Saranjit

    2014-01-01

    Liquid chromatography-mass spectrometry (LC-MS) is considered today as a mainstay tool for the structure characterization of minor components like impurities (IMPs) and degradation products (DPs) in drug substances and products. A multi-step systematic strategy for the purpose involves high resolution mass and multi-stage mass studies on both the drug and IMPs/DPs, followed by comparison of their fragmentation profiles. Its successful application requires consideration of many practical aspects at each step. The same are critically discussed in this review.

  13. Radioimmunoassay of fragment E-related neoantigen: validation studies and clinical application. [Fibrinogen-fibrin degradation products

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.P.; Hanna, W.T.; Williams, T.K.; Krauss, S. (Tennessee Univ., Knoxville (USA). Memorial Research Center and Hospital)

    1984-05-01

    An E-neoantigen radioimmunoassay (Eneo RIA) is described which can determine normal and pathological plasma levels of E-related fibrinogen-fibrin degradation products (FDP). The assay employs rabbit antiserum produced against fragment E derived from a plasmin digest of fibrinogen and subsequently absorbed with fibrinogen. The absorbed antiserum contains antibodies which are equally reactive with fibrinogen derived E (Fg-E) and fibrin derived E(Fb-E) but not with fibrinogen at 1 mg/ml. The Eneo RIA was validated by assay parallelism and by recovery experiments. Plasma Eneo immunoreactivities in 14 normals were 4-22 ng/ml (mean 12.7 ng/ml). Plasma Eneo levels in 23 of 24 patients with neoplastic and haematological diseases were elevated above normal (range 27-2027 ng/ml). Unusually high Eneo values were observed with three patients whose diseases were complicated by either disseminated intravascular coagulation (DIC) or deep vein thrombosis. After heparin therapy, the Eneo level of a patient with chronic DIC declined. A pathological plasma was eluted from a Sephadex G-200 column and Eneo immunoreactivity was determined on the eluates. The gel filtration pattern of Eneo indicates that E-related FDP is a family of plasmic fragments derived from crosslinked fibrin.

  14. Solvent degradation products in nuclear fuel processing solvents

    Energy Technology Data Exchange (ETDEWEB)

    Shook, H.E. Jr.

    1988-06-01

    The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has identified certain solvent degradation products and suggested mitigation measures. Undecanoic acid, lauric acid, and tridecanoic acid were tentatively identified as diluent degradation products in recycle solvent. These long-chain organic acids affect phase separation and lead to low decontamination factors. Solid phase extraction (SPE) was used to concentrate the organic acids in solvent prior to analysis by high performance liquid chromatography (HPLC). SPE and HPLC methods were optimized in this work for analysis of decanoic acid, undecanoic acid, and lauric acid in solvent. Accelerated solvent degradation studies with 7.5% TBP in normal paraffin hydrocarbons showed that long-chain organic acids and long-chain alkyl butyl phosphoric acids are formed by reactions with nitric acid. Degradation of both tributyl phosphate and hydrocarbon can be minimized with purified normal paraffin replacing the standard grade presently used. 12 refs., 1 fig., 3 tabs.

  15. Properties and degradability of hydrothermal carbonization products.

    Science.gov (United States)

    Eibisch, Nina; Helfrich, Mirjam; Don, Axel; Mikutta, Robert; Kruse, Andrea; Ellerbrock, Ruth; Flessa, Heinz

    2013-09-01

    Biomass carbonized via hydrothermal carbonization (HTC) yields a liquid and a carbon (C)-rich solid called hydrochar. In soil, hydrochars may act as fertilizers and promote C sequestration. We assumed that the chemical composition of the raw material (woodchips, straw, grass cuttings, or digestate) determines the properties of the liquid and solid HTC products, including their degradability. Additionally, we investigated whether easily mineralizable organic components adsorbed on the hydrochar surface influence the degradability of the hydrochars and could be removed by repetitive washing. Carbon mineralization was measured as CO production over 30 d in aerobic incubation experiments with loamy sand. Chemical analysis revealed that most nutrients were preferably enriched in the liquid phase. The C mineralization of hydrochars from woodchips (2% of total C added), straw (3%), grass (6%), and digestate (14%) were dependent on the raw material carbonized and were significantly lower (by 60-92%; < 0.05) than the mineralization of the corresponding raw materials. Washing of the hydrochars significantly decreased mineralization of digestate-hydrochar (up to 40%) but had no effect on mineralization rates of the other three hydrochars. Variations in C mineralization between different hydrochars could be explained by multiple factors, including differences in the O/C-H/C ratios, C/N ratios, lignin content, amount of oxygen-containing functional groups, and pH. In contrast to the solids, the liquid products were highly degradable, with 61 to 89% of their dissolved organic C being mineralized within 30 d. The liquids may be treated aerobically (e.g., for nutrient recovery).

  16. Photothermal degradation studies of encapsulants

    Science.gov (United States)

    Liang, R. H.

    1984-01-01

    The reliability physics program at JPL is outlined. The overall objectives and approaches are given in the program. The objectives, approaches and conclusions are given for two specific parts of the programs. These two parts are mechanistic studies of photothermal degradation and performance characteristics of materials with respect to photothermal stresses.

  17. Degradation of net primary production in a semiarid rangeland

    Science.gov (United States)

    Jackson, Hasan; Prince, Stephen D.

    2016-08-01

    Anthropogenic land degradation affects many biogeophysical processes, including reductions of net primary production (NPP). Degradation occurs at scales from small fields to continental and global. While measurement and monitoring of NPP in small areas is routine in some studies, for scales larger than 1 km2, and certainly global, there is no regular monitoring and certainly no attempt to measure degradation. Quantitative and repeatable techniques to assess the extent of deleterious effects and monitor changes are needed to evaluate its effects on, for example, economic yields of primary products such as crops, lumber, and forage, and as a measure of land surface properties which are currently missing from dynamic global vegetation models, assessments of carbon sequestration, and land surface models of heat, water, and carbon exchanges. This study employed the local NPP scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland, Australia, from 2000 to 2013. The method starts with land classification based on the environmental factors presumed to control (NPP) to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference in units of mass of carbon and percentage loss were the measure of degradation. The entire BDT (7.45 × 106 km2) was investigated at a spatial resolution of 250 × 250 m. The average annual reduction in NPP due to anthropogenic land degradation in the entire BDT was -2.14 MgC m-2 yr-1, or 17 % of the non-degraded potential, and the total reduction was -214 MgC yr-1. Extreme average annual losses of 524.8 gC m-2 yr-1 were detected. Approximately 20 % of the BDT was classified as "degraded". Varying severities and rates of degradation were found among the river basins, of which the Belyando and Suttor were highest. Interannual, negative trends in reductions of NPP occurred in 7 % of the

  18. Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: Spectroscopic and quantum chemical studies

    Science.gov (United States)

    Mansour, Ahmed M.; Shehab, Ola R.

    2014-07-01

    Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, 1H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80 °C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO-], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]ṡ4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional.

  19. Three-year study of fast-growing trees in degraded soils amended with composts: Effects on soil fertility and productivity.

    Science.gov (United States)

    Madejón, Paula; Alaejos, Joaquin; García-Álbala, José; Fernández, Manuel; Madejón, Engracia

    2016-03-15

    Currently, worries about the effects of intensive plantations on long-term nutrient supply and a loss of productivity have risen. In this study two composts were added to degraded soils where this type of intensive crops were growing, to avoid the soil fertility decrease and try to increase biomass production. For the experiment, two degraded soils in terms of low organic carbon content and low pH were selected in South-West Spain: La Rábida (RA) and Villablanca (VI) sites. Both study sites were divided into 24 plots. In RA, half of the plots were planted with Populus x canadensis "I-214"; the other half was planted with Eucalyptus globulus. At the VI site, half of the plots were planted with Paulownia fortunei, and the other plots were planted with Eucalyptus globulus. For each tree and site, three treatments were established (two organic composts and a control without compost), with four replications per treatment. The organic amendments were "alperujo" compost, AC, a solid by-product from the extraction of olive oil, and BC, biosolid compost. During the three years of experimentation, samples of soils and plants were analyzed for studying chemical and biochemical properties of soil, plant growth and plant nutritional status and biomass production. The composts increased total organic carbon, water-soluble carbon, nutrients and pH of soil only in the most acidic soil. Soil biochemical quality was calculated with the geometric mean of the enzymatic activities (Dehydrogenase, β-glucosidase, Phosphatase and Urease activities) determined in soils. The results showed a beneficial improvement in comparison with soils without compost. However, the best results were found in the growth and biomass production of the studied trees, especially in Eucalyptus. Nutritional levels of leaves of the trees were, in general, in the normal established range for each species, although no clear effect of the composts was observed. The results of this study justify the addition of

  20. Zero-valent iron mediated degradation of ciprofloxacin - assessment of adsorption, operational parameters and degradation products.

    Science.gov (United States)

    Perini, João Angelo de Lima; Silva, Bianca Ferreira; Nogueira, Raquel F Pupo

    2014-12-01

    The zero-valent iron (ZVI) mediated degradation of the antibiotic ciprofloxacin (CIP) was studied under oxic condition. Operational parameters such as ZVI concentration and initial pH value were evaluated. Increase of the ZVI concentration from 1 to 5gL(-1) resulted in a sharp increase of the observed pseudo-first order rate constant of CIP degradation, reaching a plateau at around 10 g L(-1). The contribution of adsorption to the overall removal of CIP and dissolved organic carbon (DOC) was evaluated after a procedure of acidification to pH 2.5 with sulfuric acid and sonication for 2 min. Adsorption increased as pH increased, while degradation decreased, showing that adsorption is not important for degradation. Contribution of adsorption was much more important for DOC removal than for CIP. Degradation of CIP resulted in partial defluorination since the fluoride measured corresponded to 34% of the theoretical value after 120 min of reaction. Analysis by liquid chromatography coupled to mass spectrometry showed the presence of products of hydroxylation on both piperazine and quinolonic rings generating fluorinated and defluorinated compounds as well as a product of the piperazine ring cleavage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Degradation kinetics study of cabozantinib by a novel stability-indicating LC method and identification of its major degradation products by LC/TOF-MS and LC-MS/MS.

    Science.gov (United States)

    Wu, Chunyong; Xu, Xue; Feng, Chao; Shi, Yuanyuan; Liu, Wenyuan; Zhu, Xiaoyun; Zhang, Junying

    2014-09-01

    The chemical stability of cabozantinib (CBZ) was investigated using a novel stability-indicating LC method. Forced degradation of CBZ was carried out under acidic, basic, thermal, oxidative and photolytic stress conditions. Hydrolysis and oxidation were the primary pathways for this compound and three major unknown degradation products were characterized by LC/TOF-MS and LC-MS/MS. The major oxidative degradation product was isolated by preparative LC and identified by UV, HRMS and NMR techniques to be N-{4-[(N-oxide-6,7-dimethoxyquinolin-4-yl)oxy]phenyl}-N'-(4-fluorophenyl)-cyclopropane-1,1-dicarboxamide. The developed method was validated as per ICH guidelines and then successfully applied to investigate the degradation kinetics of CBZ. Degradation of CBZ followed first-order kinetics under all experimental conditions. A V-shaped pH-rate profile over the pH range 2-10 was observed with maximum stability at pH 6. The effect of temperature on the rate of CBZ degradation was characterized using the Arrhenius equation. The activation energy for hydrolysis was 57.31kJmol(-1) in alkaline solution.

  2. Effects of Ultraviolet (UV) on Degradation of Irgafos 168 and Migration of Its Degradation Products from Polypropylene Films.

    Science.gov (United States)

    Yang, Yueping; Hu, Changying; Zhong, Huaining; Chen, Xi; Chen, Rujia; Yam, Kit L

    2016-10-05

    The effects of ultraviolet (UV) irradiation on the degradation of Irgafos 168 and the migration of its two degradation products, 2,4-di-tert-butylphenol and tris(2,4-di-tert-butylphenyl)phosphate, from polypropylene (PP) were investigated. A blown film machine was used to extrude PP films containing Irgafos 168, the films were stored in the dark for 45 days, two UV treatments and sunlight exposure were applied to the films, and GC-MS was used for degradation and migration studies. Extrusion, storage, UV treatments, and sunlight exposure significantly affected concentrations of Irgafos 168 and the degradation products. 2,4-Di-tert-butylphenol was the major degradation product produced by UV irradiation, but tris(2,4-di-tert-butylphenyl)phosphate was the major degradation product produced by extrusion, storage, and sunlight exposure. The degradation products have no or little health risk, because migration study and threshold of toxicological concern (TTC) analysis show that experimental maximum migration of 2,4-di-tert-butylphenol and tris(2,4-di-tert-butylphenyl)phosphate are only 2 and 53% of the theoretical maximum migration amounts, respectively.

  3. Degradation of diclofenac by UV-activated persulfate process: Kinetic studies, degradation pathways and toxicity assessments.

    Science.gov (United States)

    Lu, Xian; Shao, Yisheng; Gao, Naiyun; Chen, Juxiang; Zhang, Yansen; Xiang, Huiming; Guo, Youluo

    2017-03-21

    Diclofenac (DCF) is the frequently detected non-steroidal pharmaceuticals in the aquatic environment. In this study, the degradation of DCF was evaluated by UV-254nm activated persulfate (UV/PS). The degradation of DCF followed the pseudo first-order kinetics pattern. The degradation rate constant (kobs) was accelerated by UV/PS compared to UV alone and PS alone. Increasing the initial PS dosage or solution pH significantly enhanced the degradation efficiency. Presence of various natural water constituents had different effects on DCF degradation, with an enhancement or inhibition in the presence of inorganic anions (HCO3(-) or Cl(-)) and a significant inhibition in the presence of NOM. In addition, preliminary degradation mechanisms and major products were elucidated using LC-MS/MS. Hydroxylation, decarbonylation, ring-opening and cyclation reaction involving the attack of SO4(•)(-) or other substances, were the main degradation mechanism. TOC analyzer and Microtox bioassay were employed to evaluate the mineralization and cytotoxicity of solutions treated by UV/PS at different times, respectively. Limited elimination of TOC (32%) was observed during the mineralization of DCF. More toxic degradation products and their related intermediate species were formed, and the UV/PS process was suitable for removing the toxicity. Of note, longer degradation time may be considered for the final toxicity removal.

  4. Experimental studies on urea degradation in seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Rajendran, A.; Joseph, T.; Reddy, C.V.G.

    The rate of urea degradation in seawater was studied under various conditions and the kinetics of urea degradation was evaluated. Urea decomposition experiments showed that the rates and quantity of ammonium oxidation were slower in the relatively...

  5. Investigation of degradation products produced by recycling the solvent during chemical degradation of fiber-reinforced composites

    DEFF Research Database (Denmark)

    Ucar, Hülya; Simonsen, Morten Enggrob; Søgaard, Erik Gydesen

    2017-01-01

    of solvent consumption by 88%. It was found that the recycled solvent became increasingly more concentrated with degradation products from the epoxy resin and compounds produced by acetone aldol reactions. These degradation products promoted and enhanced the degradation of the composite. Among the compounds...... of the process. In this study, acetone has been used as the organic solvent. To increase the sustainability of the process, the solvent was recycled in eight consecutive batches using new glass fiber-reinforced composites in each recycling. No additional amount of acetone was added, resulting in a reduction...

  6. Characterisation and enzymic degradation of non-starch polysccharides in lignocellulosic by-products : a study on sunflower meal and palm-kernel meal

    NARCIS (Netherlands)

    Duesterhoeft, E.M.

    1993-01-01

    Non-starch polysaccharides (NSP) constitute a potentially valuable part of plant by- products deriving from the food and agricultural industries. Their use for various applications (fuel, feed, food) requires the degradation and modification of the complex plant materials. This can be

  7. Characterisation and enzymic degradation of non-starch polysccharides in lignocellulosic by-products : a study on sunflower meal and palm-kernel meal

    NARCIS (Netherlands)

    Duesterhoeft, E.M.

    1993-01-01

    Non-starch polysaccharides (NSP) constitute a potentially valuable part of plant by- products deriving from the food and agricultural industries. Their use for various applications (fuel, feed, food) requires the degradation and modification of the complex plant materials. This can be achie

  8. Characterisation and enzymic degradation of non-starch polysaccharides in lignocellulosic by-products. A study on sunflower meal and palm-kernel meal.

    NARCIS (Netherlands)

    Düsterhöft, E.M.

    1993-01-01

    Non-starch polysaccharides (NSP) constitute a potentially valuable part of plant by- products deriving from the food and agricultural industries. Their use for various applications (fuel, feed, food) requires the degradation and modification of the complex plant materials. This can be achieved by en

  9. Energetic oxygen atom material degradation studies

    Science.gov (United States)

    Caledonia, George E.; Krech, Robert H.

    1987-01-01

    As part of a study designed to test potential Shuttle surface materials for the extents of degradation and mass loss expected to be suffered in space from the velocity impacts of ambient oxygen atoms, a novel technique was developed for generation of a high flux of energetic oxygen atoms. The generation technique involves laser-induced breakdown of molecular oxygen followed by a rapid expansion of energetic oxygen atoms. The high-velocity streams developed in an evacuated hypersonic nozzle have average O-atom velocities of about 5 to 13 km/s, with an estimated total production of 10 to the 18th atoms per pulse over pulse durations of several microseconds. Results on preliminary material degradation tests conducted with this test facility have been reported by Caledonia et al. (1987). Diagrams of the experimental setup are included.

  10. Sinalbin degradation products in mild yellow mustard paste

    Directory of Open Access Journals (Sweden)

    Paunović Dragana

    2012-01-01

    Full Text Available Sinalbin degradation products in mild yellow mustard paste were investigated. The analyzed material consisted of a mild yellow mustard paste condiment and ground white mustard seeds which were originally used in the mustard paste production process. The samples were extracted in a Soxhlet extraction system and analyzed by gas chromatography - mass spectrometry (GC-MS technique. The only sinalbin degradation product in ground mustard seeds was 2-(4-hydroxyphenylacetonitrile. The most abundant sinalbin degradation product in yellow mustard paste was 4-(hydroxymethylphenol. Other compounds identified in this sample were: 4-methyl phenol, 4-ethyl phenol, 4-(2-hydroxyethylphenol and 2-(4-hydroxyphenyl ethanoic acid.

  11. On-Site Enzyme Production by Trichoderma asperellum for the Degradation of Duckweed

    DEFF Research Database (Denmark)

    Bech, Lasse; Herbst, Florian-Alexander; Grell, Morten Nedergaard

    2015-01-01

    The on-site production of cell wall degrading enzymes is an important strategy for the development of sustainable bio-refinery processes. This study concerns the optimization of production of plant cell wall-degrading enzymes produced by Trichoderma asperellum. A comparative secretome analysis...

  12. On-Site Enzyme Production by Trichoderma asperellum for the Degradation of Duckweed

    DEFF Research Database (Denmark)

    Bech, Lasse; Herbst, Florian-Alexander; Grell, Morten Nedergaard

    2015-01-01

    The on-site production of cell wall degrading enzymes is an important strategy for the development of sustainable bio-refinery processes. This study concerns the optimization of production of plant cell wall-degrading enzymes produced by Trichoderma asperellum. A comparative secretome analysis...

  13. Molecular products from the thermal degradation of glutamic acid.

    Science.gov (United States)

    Kibet, Joshua K; Khachatryan, Lavrent; Dellinger, Barry

    2013-08-14

    The thermal behavior of glutamic acid was investigated in N2 and 4% O2 in N2 under flow reactor conditions at a constant residence time of 0.2 s, within a total pyrolysis time of 3 min at 1 atm. The identification of the main pyrolysis products has been reported. Accordingly, the principal products for pyrolysis in order of decreasing abundance were succinimide, pyrrole, acetonitrile, and 2-pyrrolidone. For oxidative pyrolysis, the main products were succinimide, propiolactone, ethanol, and hydrogen cyanide. Whereas benzene, toluene, and a few low molecular weight hydrocarbons (propene, propane, 1-butene, and 2-butene) were detected during pyrolysis, no polycyclic aromatic hydrocarbons (PAHs) were detected. Oxidative pyrolysis yielded low molecular weight hydrocarbon products in trace amounts. The mechanistic channels describing the formation of the major product succinimide have been explored. The detection of succinimide (major product) and maleimide (minor product) from the thermal decomposition of glutamic acid has been reported for the first time in this study. Toxicological implications of some reaction products (HCN, acetonitrile, and acyrolnitrile), which are believed to form during heat treatment of food, tobacco burning, and drug processing, have been discussed in relation to the thermal degradation of glutamic acid.

  14. A stability indicating HPLC method for the determination of clobazam and its basic degradation product characterization

    OpenAIRE

    2014-01-01

    Background Clobazam is used for the treatment of different types of seizure and epilepsy. The present research is undertaken to study the systematic forced degradation of clobazam and to identify its main degradation product under basic conditions. Methods The degradation of clobazam was studied under different conditions. Clobazam and its degradation products were separated using a Nova-Pak C18 column and a mixture of KH2PO4 50 mM (pH 8.5) and acetonitrile (50:50, v/v) as the mobile phase wi...

  15. Phase II Nuclide Partition Laboratory Study Influence of Cellulose Degradation Products on the Transport of Nuclides from SRS Shallow Land Burial Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Serkiz, S.M.

    1999-10-04

    Degradation products of cellulosic materials (e.g., paper and wood products) can significantly influence the subsurface transport of metals and radionuclides. Codisposal of radionuclides with cellulosic materials in the E-Area slit trenches at the Savannah River Site (SRS) is, therefore, expected to influence nuclide fate and transport in the subsurface. Due to the complexities of these systems and the scarcity of site-specific data, the effects of cellulose waste loading and its subsequent influence on nuclide transport are not well established.

  16. Characterization of materials and alteration-degradation products of the Blessed Virgin Rosary altar in the Saint Dominic church in Ravenna: preliminary study for the restoration interventions

    Directory of Open Access Journals (Sweden)

    Cesare Fiori

    2003-02-01

    Full Text Available The construction of the Blessed Virgin Rosary altar in the Saint Dominic church (13th century in Ravenna occurred between 1723 and 1770. All the portions of the church are interested by intense degradation phenomena and, in particular, the altar preservation condition is worrying. The whole surface is covered by spots and deposits of various nature, efflorescences, swellings, detachments and lacunae. The main cause of damage is the humidity capillary climb. In a preliminary investigation, surveys and observations have been made in order to describe the materials and to evaluate the preservation condition. Then, the areas for sampling have been chosen for analyses and stratigraphies. The present work concerns the altar materials characterisation and the alteration – degradation products analyses: this is essential to plan the restoration interventions.

  17. Analytical protocol to study the food safety of (multiple-)recycled high-density polyethylene (HDPE) and polypropylene (PP) crates: Influence of recycling on the migration and formation of degradation products

    NARCIS (Netherlands)

    Coulier, L.; Orbons, H.G.M.; Rijk, R.

    2007-01-01

    An analytical protocol was set up and successfully applied to study the food safety of recycled HDPE and PP crates. A worst-case scenario was applied that focused not only on overall migration and specific migration of accepted starting materials but also on migratable degradation products of polyme

  18. Research of the degradation products of chitosan's angiogenic function

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jianyun; Chen Yuanwei; Ding Yulong; Shi Guoqi [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Wan Changxiu [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China)], E-mail: wanchangxiu@163.com

    2008-11-15

    Angiogenesis is of great importance in tissue engineering and has gained large attention in the past decade. But how it will be influenced by the biodegradable materials, especially their degradation products, remains unknown. Chitosan (CS) is a kind of naturally occurred polysaccharide which can be degraded in physiological environment. In order to gain some knowledge of the influences of CS degradation products on angiogenesis, the interaction of vascular endothelial cells with the degradation products was investigated in the present study. The CS degradation products were prepared by keeping CS sample in physiological saline aseptically at 37 deg. C for 120 days. Endothelial cells were co-cultured with the degradation products and the angiogenic cell behaviors, including cell proliferation, migration and tube-like structure (TLS) formation, were tested by MTT assay, cell migration quantification method (CMQM), and tube-like structure quantification method (TLSQM) respectively. Furthermore, mRNA expressions of vascular endothelial growth factor (VEGF) and matrix metallo proteinase (MMP-2) were determined by real-time reverse transcriptional polymerase chain reaction (RT-PCR). Physiological saline served as a negative control. As the results showed, the degradation products obtained from 20th to 60th day significantly inhibited the proliferation, migration, and TLS formation of endothelial cells. However, degradation products of the first 14 days and the last 30 days were found to be proangiogenic. At the molecular level, the initial results indicated that the mRNA expressions of VEGF and MMP-2 were increased by the degradation products of 7th day, but were decreased by the ones of 60th day. According to all the results, it could be concluded that the angiogenic behaviors of endothelial cells at both cellular and molecular level could be significantly stimulated or suppressed by the degradation products of CS and the influences are quite time-dependent.

  19. Towards heat-stable oxytocin formulations: analysis of degradation kinetics and identification of degradation products.

    Science.gov (United States)

    Hawe, Andrea; Poole, Robert; Romeijn, Stefan; Kasper, Piotr; van der Heijden, Rob; Jiskoot, Wim

    2009-07-01

    To investigate degradation kinetics of oxytocin as a function of temperature and pH, and identify the degradation products. Accelerated degradation of oxytocin formulated at pH 2.0, 4.5, 7.0 and 9.0 was performed at 40, 55, 70 and 80 degrees C. Degradation rate constants were determined from RP-HPLC data. Formulations were characterized by HP-SEC, UV absorption and fluorescence spectroscopy. Degradation products were identified by ESI-MS/MS. The loss of intact oxytocin in RP-HPLC was pH- and temperature-dependent and followed (pseudo) first order kinetics. Degradation was fastest at pH 9.0, followed by pH 7.0, pH 2.0 and pH 4.5. The Arrhenius equation proved suitable to describe the kinetics, with the highest activation energy (116.3 kJ/mol) being found for pH 4.5 formulations. At pH 2.0 deamidation of Gln(4), Asn(5), and Gly(9)-NH2, as well as combinations thereof were found. At pH 4.5, 7.0 and 9.0, the formation of tri- and tetrasulfide-containing oxytocin as well as different types of disulfide and dityrosine-linked dimers were found to occur. Beta-elimination and larger aggregates were also observed. At pH 9.0, mono-deamidation of Gln(4), Asn(5), and Gly(9)-NH2 additionally occurred. Multiple degradation products of oxytocin have been identified unequivocally, including various deamidated species, intramolecular oligosulfides and covalent aggregates. The strongly pH dependent degradation can be described by the Arrhenius equation.

  20. Identification and Determination of Nicorandil and its Degradation Products by HPLC and GC/MS

    Institute of Scientific and Technical Information of China (English)

    Zhong Zhou CHENG; Ze Hui JIA; Yan CHEN; Li Ying CHEN; Hua LI

    2006-01-01

    A rapid and sensitive HPLC-DAD method is developed for simultaneous determination of nicorandil and its degradation products, N-(2-hydroxyethyl) nicotinamide, nitrate ion and nicotinic acid, using nicotinamide (NT) as internal standard, at wavelength 204 nm. Nicotinic acid is identified by HPLC and GC/MS. The method can also be applied to study kinetic of degradation processes of nicorandil in storage.

  1. Strongly increased levels of fibrinogen elastase degradation products in patients with ischemic stroke

    NARCIS (Netherlands)

    Lau, L.M.L. de; Cheung, E.Y.L.; Kluft, C.; Leebeek, F.W.G.; Meijer, P.; Laterveer, R.; Dippel, D.W.J.; Maat, M.P.M.de

    2008-01-01

    Ischemic stroke is associated with leucocyte activation. Activated leucocytes release elastase, an enzyme that can degrade fibrinogen. Fibrinogen elastase degradation products (FgEDP) may serve as a specific marker of elastase proteolytic activity. In a case-control study of 111 ischemic stroke pati

  2. Strongly increased levels of fibrinogen elastase degradation products in patients with ischemic stroke

    NARCIS (Netherlands)

    Lau, L.M.L. de; Cheung, E.Y.L.; Kluft, C.; Leebeek, F.W.G.; Meijer, P.; Laterveer, R.; Dippel, D.W.J.; Maat, M.P.M.de

    2008-01-01

    Ischemic stroke is associated with leucocyte activation. Activated leucocytes release elastase, an enzyme that can degrade fibrinogen. Fibrinogen elastase degradation products (FgEDP) may serve as a specific marker of elastase proteolytic activity. In a case-control study of 111 ischemic stroke pati

  3. Advanced Cell Development and Degradation Studies

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; C. M. Stoots; J. S. Herring; R. C. O' Brien; K. G. Condie; M. Sohal; G. K. Housley; J. J. Hartvigsen; D. Larsen; G. Tao; B. Yildiz; V. Sharma; P. Singh; N. Petigny; T. L. Cable

    2010-09-01

    The Idaho National Laboratory (INL) has been researching the application of solid-oxide electrolysis cells for large-scale hydrogen production from steam over a temperature range of 800 to 900ºC. From 2003 – 2009, this work was sponsored by the DOE Nuclear Hydrogen Initiative (NHI). Starting in 2010, the HTE research program has been sponsored by the Next Generation Nuclear Plant (NGNP) program. HTSE research priorities in FY10 are centered on understanding and reducing cell and stack performance degradation to an acceptable level to advance the technology readiness level of HTSE and to justify further large-scale demonstration activities. This report provides a summary of our FY10 experimental program, which has been focused on advanced cell and stack development and degradation studies. Advanced cell and stack development activities are under way at five technology partners: MSRI, Versa Power, Ceramatec, NASA Glenn, and St. Gobain. Performance evaluation of the advanced technology cells and stacks has been performed by the technology partners, by MIT and the University of Connecticut and at the INL HTE Laboratory. Summaries of these development activities and test results are presented.

  4. In vitro degradation and total gas production of byproducts generated in the biodiesel production chain

    Directory of Open Access Journals (Sweden)

    Raissa Kiara oliveira de Morais

    2015-05-01

    Full Text Available This study aimed to evaluate the in vitro degradation and total gas production of different oil seed press cakes from a biodiesel production chain gas through the use of a semi-automatic technique of gas production in vitro. The treatments consisted of substituting elephant grass in increasing levels, 0%, 30, 50 and 70%, with the byproducts of Gossyypium hirsutum, Ricinus communis, Moringa oleifeira, Jatropha curcas and Helianthus annus. The oil seed press cakes of Moringa oleifeira had the highest rate of in vitro degradation of dry matter compared with other foods but did not result in a higher final volume of gases production. Gossyypium hirsutum, Pinhão manso curcas and Ricinus communis showed a higher in vitro degradability of similar dry matter. The highest total gas production was obtained by the oil seed press cakes of Helianthus annus. The oil seed press cakes of Moringa oleifeira can replace elephant grass up to 70% and therefore reduce both greenhouse gas emissions and energy loss for the animal.

  5. Characterization of the Oxidative Degradation Product of Darunavir by LC-MS/MS

    Science.gov (United States)

    Yamjala, Karthik; Atukuri, Jeevitha; Nagappan, Krishnaveni; Halekote Shivaraju, Nivedeetha; Subramania Nainar, Meyyanathan

    2015-01-01

    A rapid, selective, and reliable LC-MSn method has been developed and validated for the isolation and structural characterization of the degradation product of darunavir (DRV). DRV, an HIV-1 protease inhibitor, was subjected to intrinsic oxidative stress conditions using 30% hydrogen peroxide and the degradation profile was studied. The oxidative degradation of DRV resulted in one degradation product. The unknown degradation product was separated on a Hibar Purospher C18 (250 mm × 4.6 mm; 5 µm) column by using 0.01 M ammonium formate (pH 3.0) and acetonitrile as mobile phase in the ratio of 50:50, v/v. The eluents were monitored at 263 nm using a UV detector. The isolated degradation product was characterized by UPLC-Q-TOF and its fragmentation pathway was proposed. The proposed structure of the degradation product was confirmed by HRMS analysis. The developed stability-indicating LC method was validated with respect to accuracy, precision, specificity/selectivity, and linearity. No prior reports were found in the literature about the oxidative degradation behavior of DRV. PMID:26839843

  6. Study of the degradation behaviour of dimethoate under microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei [College of Chemistry and Chemical Engineering, Liaoning University, Shenyang 110036 (China)], E-mail: zhanglei63@126.com; Guo Xingjia; Yan Fei; Su Mingming; Li Ying [College of Chemistry and Chemical Engineering, Liaoning University, Shenyang 110036 (China)

    2007-11-19

    In this work, the degradation of dimethoate under microwave irradiation assisted advanced oxidation processes (MW/oxidants) were studied. The efficiencies of the degradation of dimethoate in dilute aqueous solutions for a variety of oxidants with or without MW irradiation were compared. The results showed that the synergistic effects between MW and K{sub 2}S{sub 2}O{sub 8} had high degradation efficiency for dimethoate. Simultaneously, UV/TiO{sub 2}/K{sub 2}S{sub 2}O{sub 8} photocatalytic oxidation degradation of dimethoate was investigated. The experimental results indicated that the method of microwave degradation of organic pollutants in the presence of oxidant could reduce reaction time and improve product yield. Microwave irradiation was an advisable choice for treating organic wastewaters and has a widely application perspective for non- or low-transparent and fuscous dye wastewaters.

  7. Development of forced degradation and stability indicating studies of drugs-A review

    Institute of Scientific and Technical Information of China (English)

    Blessy Mn; Ruchi D. Patel; Prajesh N. Prajapati; Y.K. Agrawal

    2014-01-01

    Forced degradation is a degradation of new drug substance and drug product at conditions more severe than accelerated conditions. It is required to demonstrate specificity of stability indicating methods and also provides an insight into degradation pathways and degradation products of the drug substance and helps in elucidation of the structure of the degradation products. Forced degradation studies show the chemical behavior of the molecule which in turn helps in the development of formulation and package. In addition, the regulatory guidance is very general and does not explain about the performance of forced degradation studies. Thus, this review discusses the current trends in performance of forced degradation studies by providing a strategy for conducting studies on degradation mechanisms and also describes the analytical methods helpful for development of stability indicating method.

  8. High glucose promotes Aβ production by inhibiting APP degradation.

    Directory of Open Access Journals (Sweden)

    Yi Yang

    Full Text Available Abnormal deposition of neuriticplaques is the uniqueneuropathological hallmark of Alzheimer's disease (AD.Amyloid β protein (Aβ, the major component of plaques, is generated from sequential cleavage of amyloidβ precursor protein (APP by β-secretase and γ-secretase complex. Patients with diabetes mellitus (DM, characterized by chronic hyperglycemia,have increased risk of AD development.However, the role of high blood glucose in APP processing and Aβ generation remains elusive. In this study, we investigated the effect of high glucose on APP metabolism and Aβ generation in cultured human cells. We found that high glucose treatment significantly increased APP protein level in both neuronal-like and non-neuronal cells, and promoted Aβ generation. Furthermore, we found that high glucose-induced increase of APP level was not due to enhancement of APP gene transcription but resulted from inhibition of APP protein degradation. Taken together, our data indicated that hyperglycemia could promote AD pathogenesis by inhibiting APP degradation and enhancing Aβ production. More importantly, the elevation of APP level and Aβ generation by high glucose was caused by reduction of APP turnover rate.Thus,our study provides a molecular mechanism of increased risk of developing AD in patients withDMand suggests thatglycemic control might be potentially beneficial for reducing the incidence of AD in diabetic patients and delaying the AD progression.

  9. Degradation study of different brands of paracetamol by UV spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Safila Naveed; Humera Ishaq; Sheeba Urooj

    2016-01-01

    Objective: To investgate the forced degradation study for the determination of degradation of the drug substance. Methods: Paracetamol was exposed to different conditions according to International Conference on Harmonization guideline. The amount of degradation product can be calculated with the help of UV spectrophotometer. The official test limits according to British Pharmacopoeia/United States Pharmacopoeia should not less than and should not more than lapelled amount. Forced degradation of drug substance was exposed to acidic and basic medium of panadol.Forced degradation of drug substance of panadol,disprol and calpol were also observed negligible difference in availability on exposure to UV and heat. This method can be used successfully for studying the stress degradation factors. Because this method is less time consuming and simple and cost effective also. Results:The brandsi.e. calpol, panadol and disprol, when they come in contact with different degradation parameters (before, acid, base, heat and UV treatments) according to statistical analysis, the result showed significant values (P Conclusions:The result indicated there is no degradation found in these brands.

  10. Enzymatic degradation of plutonium-contaminated cellulose products

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, C.E.; Rainwater, K.A.; Swift, L.M. [Texas Tech Univ., Lubbock, TX (United States); Barnes, D.L. [Amarillo National Resource Center for Plutonium, TX (United States); Worl, L.; Avens, L. [Los Alamos National Lab., NM (United States)

    1999-03-01

    Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated either with crude oil or with radionuclides. This presentation describes the use of one such enzyme preparation (Rapidase{trademark}) for the degradation of cotton sorbents intentionally contaminated with low levels of plutonium. This is part of a feasibility study to determine if such treatments have a role in reducing the volume of low level and transuranic wastes to minimize the amount of radionuclide-contaminated waste that must be disposed of in secured storage areas.

  11. Enzymatic degradation of plutonium-contaminated cellulose products

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, C.E.; Rainwater, K.A.; Swift, L.M. [Texas Tech Univ., Lubbock, TX (United States); Barnes, D.L. [Amarillo National Resource Center for Plutonium, TX (United States); Worl, L.A. [Los Alamos National Lab., NM (United States)

    1999-06-01

    Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown previously that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated either with crude oil or with uranium. This presentation describes the use of one such enzyme preparation (Rapidase{trademark}, manufactured by Genencor, Rochester, NY) for the degradation of cotton sorbents intentionally contaminated with low levels of plutonium. This is part of a feasibility study to determine if such treatments have a role in reducing the volume of low level and transuranic wastes to minimize the amount of radionuclide-contaminated waste destined for costly disposal options.

  12. Enzymatic degradation of plutonium-contaminated cellulose products

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, C.E.; Rainwater, K.A.; Swift, L.M. [Texas Tech Univ., Lubbock, TX (United States); Barnes, D.L. [Amarillo National Resource Center for Plutonium, TX (United States); Worl, L.A. [Los Alamos National Lab., NM (United States)

    1999-06-01

    Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown previously that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated either with crude oil or with uranium. This presentation describes the use of one such enzyme preparation (Rapidase{trademark}, manufactured by Genencor, Rochester, NY) for the degradation of cotton sorbents intentionally contaminated with low levels of plutonium. This is part of a feasibility study to determine if such treatments have a role in reducing the volume of low level and transuranic wastes to minimize the amount of radionuclide-contaminated waste destined for costly disposal options.

  13. Kinetics and Degradation Products of Trichloroethene.

    Science.gov (United States)

    1986-05-01

    hindrance. In early copolymerization studies the relative rates of addition of acrylonitrile , vinylacetate and styrene radical were determined. The...human carcinogen . 6. Anaerobic biodegradation of TCE operates via reductive dehalogenation. 7. More studies are needed to investigate these findings...Again, due to convection and direct exposure to air, volatilization would be expected to be a dominant fate mechanism. 72 D. VADOSE ZONE Much of the

  14. Development of a sensor for polypropylene degradation products.

    Energy Technology Data Exchange (ETDEWEB)

    Sawyer, Patricia Sue; Howell, Stephen Wayne; Hochrein, James Michael; Dirk, Shawn M.; Bernstein, Robert; Washburn, Cody M.; Graf, Darin C.

    2009-04-01

    This paper presents the development of a sensor to detect the oxidative and radiation induced degradation of polypropylene. Recently we have examined the use of crosslinked assemblies of nanoparticles as a chemiresistor-type sensor for the degradation products. We have developed a simple method that uses a siloxane matrix to fabricate a chemiresistor-type sensor that minimizes the swelling transduction mechanism while optimizing the change in dielectric response. These sensors were exposed with the use of a gas chromatography system to three previously identified polypropylene degradation products including 4-methyl-2-pentanone, acetone, and 2-pentanone. The limits of detection 210 ppb for 4-methy-2-pentanone, 575 ppb for 2-pentanone, and the LoD was unable to be determined for acetone due to incomplete separation from the carbon disulfide carrier.

  15. Time-of-flight mass spectrometry assessment of fluconazole and climbazole UV and UV/H2O2 degradability: Kinetics study and transformation products elucidation.

    Science.gov (United States)

    Castro, Gabriela; Casado, Jorge; Rodríguez, Isaac; Ramil, María; Ferradás, Aida; Cela, Rafael

    2016-01-01

    The efficiency of UV irradiation for the removal of the antimycotic drugs fluconazole (FCZ) and climbazole (CBZ) from water samples is evaluated. Degradation experiments, at laboratory scale, were carried out with spiked aliquots of ultrapure water solutions and treated wastewater samples using low-pressure mercury lamps emitting at 254 nm. Time course of precursor pollutants and identification of arising transformation products (TPs) was performed by injection of different reaction time aliquots in a liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) system. Chemical structures of identified TPs were proposed from their full-product ion spectra, acquired using different collision energies. During UV irradiation experiments, the half-lives (t1/2) of FCZ and CBZ were similar in ultrapure water solutions and wastewater samples; however, the first species was more recalcitrant than the second one. Four TPs were identified in case of FCZ resulting from substitution of fluorine atoms by hydroxyl moieties and intramolecular cyclization with fluorine removal. CBZ interacted with UV radiation through reductive dechlorination, hydroxylation and cleavage of the ether bond; moreover, five additional primary TPs, with the same empirical formula as CBZ, were also noticed. Given the relatively long t1/2 of FCZ under direct photolysis (ca. 42 min), UV irradiation was combined with H2O2 addition to promote formation of reactive hydroxyl radicals. Under such conditions, the degradation rate of FCZ was enhanced significantly and no TPs were detected. These latter conditions allowed also the effective removal of CBZ TPs.

  16. Chemical Degradation of the Cathodic Electrical Contact Between Carbon and Cast Iron in Aluminum Production Cells

    Science.gov (United States)

    Brassard, Martin; Désilets, Martin; Soucy, Gervais; Bilodeau, Jean-François; Forté, Martin

    2017-06-01

    The cathodic carbon to cast iron electrical contact degradation is one of the factors to consider in the cathode voltage drop (CVD) increase over the lifetime of aluminum production cells. Lab-scale experiments were carried out to study the cast iron to carbon interface chemical degradation and the impact of important cell parameters like temperature and bath chemistry. Laboratory degradation results were compared with industrial samples. A thermoelectric Ansys numerical model was then used to predict the effect of cast iron surface degradation over CVD. Results show that the aluminum formation on the cast iron surface and its subsequent diffusion creates an immiscible mixture of Fe-Al metal alloy and electrolytic bath. Disparities were also observed between industrial samples taken from two different technologies, suggesting that the degradation can be slowed down. Thermoelectric calculations finally revealed that the impact of the contact resistance augmentation is by far greater than the cast iron degradation.

  17. Chemical Degradation of the Cathodic Electrical Contact Between Carbon and Cast Iron in Aluminum Production Cells

    Science.gov (United States)

    Brassard, Martin; Désilets, Martin; Soucy, Gervais; Bilodeau, Jean-François; Forté, Martin

    2017-02-01

    The cathodic carbon to cast iron electrical contact degradation is one of the factors to consider in the cathode voltage drop (CVD) increase over the lifetime of aluminum production cells. Lab-scale experiments were carried out to study the cast iron to carbon interface chemical degradation and the impact of important cell parameters like temperature and bath chemistry. Laboratory degradation results were compared with industrial samples. A thermoelectric Ansys numerical model was then used to predict the effect of cast iron surface degradation over CVD. Results show that the aluminum formation on the cast iron surface and its subsequent diffusion creates an immiscible mixture of Fe-Al metal alloy and electrolytic bath. Disparities were also observed between industrial samples taken from two different technologies, suggesting that the degradation can be slowed down. Thermoelectric calculations finally revealed that the impact of the contact resistance augmentation is by far greater than the cast iron degradation.

  18. Restoration of Degraded Salt Affected Lands to Productive Forest Ecosystem

    Science.gov (United States)

    Singh, Yash; Singh, Gurbachan; Singh, Bajrang; Cerdà, Artemi

    2017-04-01

    time but it appears to be driven by two parallel sets of ameliorative mechanisms like (i) fertility building process associated with organic matter addition, nitrogen accretion and nutrient recycling (ii) sodicity alleviation process driven by improved leaching that lead to reduced soil dispersion and less sodium toxicity. The index of these changes in the soil depends on the age of the forest. The present paper is based on the 15 years field study conducted to find out the rate and time that is required to achieve the status at par with a reference site of natural forest of the region, a stage where aim of degraded salt affected soils may be diverted to productive forest ecosystem. Changes in soil properties were recorded under canopy of various aged plantations. Most of the leguminous species raised on degraded sodic soils rendered an appreciable reduction in soil pH and exchangeable sodium (ESP), decrease in bulk density and increasing in soil porosity and water holding capacity. Exchangeable K, Ca, Mg and organic carbon content increased with plant growth and age. As a result of afforestation, a significant increase in soil organic matter (4 times) and decrease in pH from 10.2 to 8.6 were recorded. Total available N was increased 2-4 times in forested soil in comparison to barren soil. Acknowledgements. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603498 (RECARE project) References. Brevik, E. C., Cerdà, A., Mataix-Solera, J., Pereg, L., Quinton, J. N., Six, J., and Van Oost, K. 2015. The interdisciplinary nature of SOIL, SOIL, 1, 117-129, doi:10.5194/soil-1-117-2015 Celentano, D., G. X. Rousseau, V. L. Engel, M. Zelarayán, E. C. Oliveira, A. C. M. Araujo, and E. G. de Moura. 2016. Degradation of Riparian Forest Affects Soil Properties and Ecosystem Services Provision in Eastern Amazon of Brazil. Land Degradation and Development. doi:10.1002/ldr.2547

  19. Accelerated degradation studies of encapsulation polymers

    Science.gov (United States)

    Weiss, Karl-Anders; Huelsmann, Jan Philip; Kaltenbach, Thomas; Philipp, Daniel; Schuhmacher, Tanja; Wirth, Jochen; Koehl, Michael

    2008-08-01

    The estimation of PV-modules lifetime facilitates the further development and helps to lower risks for producers and investors. One base for this extensive testing and simulation work is the knowledge of the chemical degradation processes and their kinetics, as well as of the permeation of water and oxygen into the module, especially of the encapsulant. Besides ethylen-vinylacetate copolymer (EVA), which is the dominant material for encapsulation, new materials become available and need the assessment of their properties and the durability impact. Accelerated durability tests were performed on different EVA materials. The paper reports on several measurement methods for analysis of the polymers that were used, FT-IR with attenuated total reflection (ATR), and Raman microscopy, e.g. It is very important to identify degradation products and intermediates in order to identify the leading degradation processes and their kinetics as well as potential interactions between different processes. Another important factor for the degradation of the PV-modules and the concerned polymers in particular is the permeation of reactive substances, especially of water vapor, into and inside the modules. The paper shows results of permeation measurements of the new materials, as well as FEM-based numerical simulations of the humidity diffusion within a PV-module what is an important step towards the calculation of the chemical degradation using numerical simulation tools in the future.

  20. Polarography of an acidic degradation product from cephalexin.

    Science.gov (United States)

    Nuñez-Vergara, L J; Squella, J A; Silva, M M

    1982-02-01

    2-Hydroxy-3-phenyl-6-methylpyrazine is identified as the product obtained by acidic degradation of cephalexin in the presence of formaldehyde. In 5M hydrochloric acid this product gives a well-defined reduction wave with a half-wave potential of -0.45 V vs. SCE. The wave is irreversible and diffusion-controlled. The diffusion current shows a linear relation with the cephalexin concentration and can be used for determination of cephalexin in plasma.

  1. Degradation of the pharmaceuticals diclofenac and sulfamethoxazole and their transformation products under controlled environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Poirier-Larabie, S. [Aquatic Contaminants Research Division, Science and Water Technology Directorate, Environment Canada, Montréal, Québec H2Y 2E7 (Canada); Segura, P.A. [Department of Chemistry, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1 (Canada); Gagnon, C., E-mail: christian.gagnon@canada.ca [Aquatic Contaminants Research Division, Science and Water Technology Directorate, Environment Canada, Montréal, Québec H2Y 2E7 (Canada)

    2016-07-01

    Contamination of the aquatic environment by pharmaceuticals via urban effluents is well known. Several classes of drugs have been identified in waterways surrounding these effluents in the last 15 years. To better understand the fate of pharmaceuticals in ecosystems, degradation processes need to be investigated and transformation products must be identified. Thus, this study presents the first comparative study between three different natural environmental conditions: photolysis and biodegradation in aerobic and anaerobic conditions both in the dark of diclofenac and sulfamethoxazole, two common drugs present in significant amounts in impacted surface waters. Results indicated that degradation kinetics differed depending on the process and the type of drug and the observed transformation products also differed among these exposure conditions. Diclofenac was nearly degraded by photolysis after 4 days, while its concentration only decreased by 42% after 57 days of exposure to bacteria in aerobic media and barely 1% in anaerobic media. For sulfamethoxazole, 84% of the initial concentration was still present after 11 days of exposure to light, while biodegradation decreased its concentration by 33% after 58 days of exposure under aerobic conditions and 5% after 70 days of anaerobic exposure. In addition, several transformation products were observed and persisted over time while others degraded in turn. For diclofenac, chlorine atoms were lost primarily in the photolysis, while a redox reaction was promoted by biodegradation under aerobic conditions. For sulfamethoxazole, isomerization was favored by photolysis while a redox reaction was also favored by the biodegradation under aerobic conditions. To summarize this study points out the occurrence of different transformation products under variable degradation conditions and demonstrates that specific functional groups are involved in the tested natural attenuation processes. Given the complexity of environmental

  2. Effect of protein degradability on milk production of dairy ewes.

    Science.gov (United States)

    Mikolayunas-Sandrock, C; Armentano, L E; Thomas, D L; Berger, Y M

    2009-09-01

    The objective of this experiment was to determine the effect of protein degradability of dairy sheep diets on milk yield and protein utilization across 2 levels of milk production. Three diets were formulated to provide similar energy concentrations and varying concentrations of rumen-degradable protein (RDP) and rumen-undegradable protein (RUP): 12% RDP and 4% RUP (12-4) included basal levels of RDP and RUP, 12% RDP and 6% RUP (12-6) included additional RUP, and 14% RDP and 4% RUP (14-4) included additional RDP. Diets were composed of alfalfa-timothy cubes, whole and ground corn, whole oats, dehulled soybean meal, and expeller soybean meal (SoyPlus, West Central, Ralston, IA). Estimates of RDP and RUP were based on the Small Ruminant Nutrition System model (2008) and feed and orts were analyzed for Cornell N fractions. Eighteen multiparous dairy ewes in midlactation were divided by milk yield (low and high) into 2 blocks of 9 ewes each and were randomly assigned within block (low and high) to 3 pens of 3 ewes each. Dietary treatments were arranged in a 3 x 3 Latin square within each block and applied to pens for 14-d periods. We hypothesized that pens consuming high-RUP diets (12-6) would produce more milk and milk protein than the basal diet (12-4) and pens consuming high-RDP diets (14-4) would not produce more milk than the basal diet (12-4). Ewes in the high-milk-yield square consumed more dry matter and produced more milk, milk fat, and milk protein than ewes in the low-milk-yield square. There was no effect of dietary treatment on dry matter intake. Across both levels of milk production, the 12-6 diet increased milk yield by 14%, increased milk fat yield by 14%, and increased milk protein yield by 13% compared with the 14-4 and 12-4 diets. Gross N efficiency (milk protein N/intake protein N) was 11 and 15% greater in the 12-6 and 12-4 diets, respectively, compared with the 14-4 diet. Milk urea N concentration was greater in the 12-6 diet and tended to be

  3. Degradation products of the artificial azo dye, Allura red, inhibit esterase activity of carbonic anhydrase II: A basic in vitro study on the food safety of the colorant in terms of enzyme inhibition.

    Science.gov (United States)

    Esmaeili, Sajjad; Ashrafi-Kooshk, Mohammad Reza; Khaledian, Koestan; Adibi, Hadi; Rouhani, Shohre; Khodarahmi, Reza

    2016-12-15

    Allura red is a widely used food colorant, but there is debate on its potential security risk. In the present study, we found that degradation products of the dye were more potent agents with higher carbonic anhydrase inhibitory action than the parent dye. The mechanism by which the compounds inhibit the enzyme activity has been determined as competitive mode. In addition, the enzyme binding properties of the compounds were investigated employing different spectroscopic techniques and molecular docking. The analyses of fluorescence quenching data revealed the existence of the same binding site for the compounds on the enzyme molecule. The thermodynamic parameters of ligand binding were not similar, which indicates that different interactions are responsible in binding of the parent dye and degradation products to the enzyme. It appears that enzyme inhibition should be considered, more seriously, as a new opened dimension in food safety.

  4. Identification by CI-mass spectrometry of an unexpected benzodiazepine degradation product

    Science.gov (United States)

    Buret, D.; Breton, D.; Clair, P.; Lafosse, M.

    2006-01-01

    The French Military Health Service (SSA) has developed an innovative drug product, as a treatment against neurotoxic organophosphate poisoning (NOP). It contains three drug substances: an anticholinergic, an anticonvulsant and a cholinesterase reactivator. Testing stability study, in normal conditions, over 18 months, for this speciality, has given unexpected results. Indeed, one of the drug substances, avizafone (pro-drug of diazepam), breaks down partially into a compound which migrates into the plastic container where this degradation product is demethylated after absorption. Mass spectrometry with negative chemical ionisation (negative CI-MS) was used, to monitor decomposition of the drug substance. This method first showed migration of the degradation product and has been used to monitor its evolution during the stability testing study. The demethylation seems to be due to an additive product present in the plastic. The degradation products remain trapped in the container holding the pharmaceutical formulation.

  5. Production and degradation of polyhydroxyalkanoates in waste environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.Y.; Choi, J. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of)

    1999-06-01

    Polyhydroxyalkanoates (PHAs) are energy/carbon storage materials accumulated under unfavorable growth condition in the presence of excess carbon source. PHAs are attracting much attention as substitute for non-degradable petrochemically derived plastics because of their similar material properties to conventional plastics and complete biodegradability under natural environment upon disposal. In this paper, PHA production and degradation in waste environment as well as its role in biological phosphorus removal are reviewed. In biological phosphorus removal process, bacteria accumulating polyphosphate (poly P) uptake carbon substrates and accumulate these as PHA by utilizing energy from breaking down poly P under anaerobic conditions. In the following aerobic condition, accumulated PHA is utilized for energy generation and for the regeneration of poly P. PHA production from waste has been investigated in order to utilize abundant organic compounds in waste water. Since PHA content and PHA productivity that can be obtained are rather low, PHA production from waste product should be considered as a coupled process for reducing the amount of organic waste. PHAs can be rapidly degraded to completion in municipal anaerobic sludge by various microorganisms.

  6. Ozonation of metoprolol in aqueous solution: ozonation by-products and mechanisms of degradation.

    Science.gov (United States)

    Tay, Kheng Soo; Rahman, Noorsaadah Abd; Abas, Mhd Radzi Bin

    2013-05-01

    This study investigated the degradation pathway of metoprolol, a widely used β-blocker, in the ozonation via the identification of generated ozonation by-products (OPs). Structure elucidation of OPs was performed using HPLC coupled with quadrupole time-of-flight high-resolution mass spectrometry. Seven OPs were identified, and four of these have not been reported elsewhere. Identified OPs of metoprolol included aromatic ring breakdown by-products; aliphatic chain degraded by-products and aromatic ring mono-, di-, and tetrahydroxylated derivatives. Based on the detected OPs, metoprolol could be degraded through aromatic ring opening reaction via reaction with ozone (O3) and degradation of aliphatic chain and aromatic ring via reaction with hydroxyl radical (•OH).

  7. Identification and characterization of process-related substances and degradation products in apremilast: Process optimization and degradation pathway elucidation.

    Science.gov (United States)

    Lu, Yuting; Shen, Xiaoyue; Hang, Taijun; Song, Min

    2017-07-15

    This study aims at investigating the separation, identification and characterization of related substances in apremilast by LC-MS hyphenated techniques, as well as the synthesis optimization and the degradation pathways elucidation. Forced degradation studies were conducted under the ICH prescribed stress conditions. The chromatographic separation was achieved on XBridge C18 column (4.6mm×150mm, 3.5μm) using a mobile phase consisting of water adjusted to pH 3.0 with formic acid as solvent A and acetonitrile as solvent B in linear gradient elution program. Twelve related substances were detected all together in apremilast and its stress samples. Their structures were identified mainly through positive ESI high-resolution TOF-MS analysis of the parent ions' accurate masses and elemental compositions, and the corresponding MS/MS spectra elucidation. There were three process-related substances and nine degradation products, seven of them were first reported. Two degradation products and one process-related substance were further verified by semi-preparation and NMR determination. Their origins and formation mechanisms were also discussed, based on which effective approaches for the synthesis optimization were conducted. Therefore, the related substances investigation are valuable for apremilast manufacturing process optimization and quality control. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Characterization of degradation products of amorphous and polymorphic forms of clopidogrel bisulphate under solid state stress conditions

    DEFF Research Database (Denmark)

    Raijada, Dhara K; Prasad, Bhagwat; Paudel, Amrit

    2010-01-01

    The present study deals with the stress degradation studies on amorphous and polymorphic forms of clopidogrel bisulphate. The objective was to characterize the degradation products and postulate mechanism of decomposition of the drug under solid state stress conditions. For that, amorphous form...... degradation products were observed under various stress conditions. The structures of all of them were elucidated using LC-MS/TOF and LC-MS(n) studies. While one matched the known hydrolytic decomposition product of the drug in solution, seven others were new. The postulated degradation pathway and mechanism...

  9. Investigation of degradation products of cocaine and benzoylecgonine in the aquatic environment

    Energy Technology Data Exchange (ETDEWEB)

    Bijlsma, Lubertus; Boix, Clara [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellón (Spain); Niessen, Wilfried M.A. [hyphen MassSpec, Leiden (Netherlands); Ibáñez, María; Sancho, Juan V. [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellón (Spain); Hernández, Félix, E-mail: felix.hernandez@uji.es [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellón (Spain)

    2013-01-15

    In this work, ultra-high-performance liquid chromatography (UHPLC) coupled to a hybrid quadrupole time-of-flight mass spectrometer (QTOF MS) has allowed the discovery and elucidation of degradation products of cocaine and its main metabolite benzoylecgonine (BE) in water. Spiked surface water was subjected to hydrolysis, chlorination and photo-degradation (both ultraviolet irradiation and simulated sunlight). After degradation of cocaine, up to sixteen compounds were detected and tentatively identified (1 resulting from hydrolysis; 8 from chlorination; 7 from photo-degradation), three of which are well known cocaine metabolites (BE, norbenzoylecgonine and norcocaine). Regarding BE degradation, up to ten compounds were found (3 from chlorination; 7 from photo-degradation), including one known metabolite (norbenzoylecgonine). Since reference standards were available for the major metabolites, they could be confirmed using information on retention time and fragment ions. The other degradates resulted from chlorination, dealkylation, hydroxylation and nitration, or from a combination of these processes. Several influent and effluent sewage water, and surface water samples were then screened for the identified compounds (known and unknown) using UHPLC–tandem MS with triple quadrupole. BE, norcocaine and norbenzoylecgonine were identified in these samples as major metabolites. Four previously unreported degradates were also found in some of the samples under study, illustrating the usefulness and applicability of the degradation experiments performed in this work. Highlights: ► Cocaine and benzoylecgonine degradation/transformation products investigated in water ► Hydrolysis, chlorination and photo degradation studied under laboratory conditions ► Several TPs discovered and tentatively elucidated by high resolution MS ► Structures of non-previously reported TPs have been suggested. ► Several reported/known TPs but also new TPs were found in sewage and surface

  10. The effects of grassland degradation on plant diversity, primary productivity, and soil fertility in the alpine region of Asia's headwaters.

    Science.gov (United States)

    Wang, Xuexia; Dong, Shikui; Yang, Bing; Li, Yuanyuan; Su, Xukun

    2014-10-01

    A 3-year survey was conducted to explore the relationships among plant composition, productivity, and soil fertility characterizing four different degradation stages of an alpine meadow in the source region of the Yangtze and Yellow Rivers, China. Results showed that plant species diversity, productivity, and soil fertility of the top 30-cm soil layer significantly declined with degradation stages of alpine meadow over the study period. The productivity of forbs significantly increased with degradation stages, and the soil potassium stock was not affected by grassland degradation. The vegetation composition gradually shifted from perennial graminoids (grasses and sedges) to annual forbs along the degradation gradient. The abrupt change of response in plant diversity, plant productivity, and soil nutrients was demonstrated after heavy grassland degradation. Moreover, degradation can indicate plant species diversity and productivity through changing soil fertility. However, the clear relationships are difficult to establish. In conclusion, degradation influenced ecosystem function and services, such as plant species diversity, productivity, and soil carbon and nitrogen stocks. Additionally, both plant species diversity and soil nutrients were important predictors in different degradation stages of alpine meadows. To this end, heavy degradation grade was shown to cause shift of plant community in alpine meadow, which provided an important basis for sustaining ecosystem function, manipulating the vegetation composition of the area and restoring the degraded alpine grassland.

  11. Counteraction of antibiotic production and degradation stabilizes microbial communities

    Science.gov (United States)

    Kelsic, Eric D.; Zhao, Jeffrey; Vetsigian, Kalin; Kishony, Roy

    2015-01-01

    Summary A major challenge in theoretical ecology is understanding how natural microbial communities support species diversity1-8, and in particular how antibiotic producing, sensitive and resistant species coexist9-15. While cyclic “rock-paper-scissors” interactions can stabilize communities in spatial environments9-11, coexistence in unstructured environments remains an enigma12,16. Here, using simulations and analytical models, we show that the opposing actions of antibiotic production and degradation enable coexistence even in well-mixed environments. Coexistence depends on 3-way interactions where an antibiotic degrading species attenuates the inhibitory interactions between two other species. These 3-way interactions enable coexistence that is robust to substantial differences in inherent species growth rates and to invasion by “cheating” species that cease producing or degrading antibiotics. At least two antibiotics are required for stability, with greater numbers of antibiotics enabling more complex communities and diverse dynamical behaviors ranging from stable fixed-points to limit cycles and chaos. Together, these results show how multi-species antibiotic interactions can generate ecological stability in both spatial and mixed microbial communities, suggesting strategies for engineering synthetic ecosystems and highlighting the importance of toxin production and degradation for microbial biodiversity. PMID:25992546

  12. Counteraction of antibiotic production and degradation stabilizes microbial communities.

    Science.gov (United States)

    Kelsic, Eric D; Zhao, Jeffrey; Vetsigian, Kalin; Kishony, Roy

    2015-05-28

    A major challenge in theoretical ecology is understanding how natural microbial communities support species diversity, and in particular how antibiotic-producing, -sensitive and -resistant species coexist. While cyclic ‘rock–paper–scissors’ interactions can stabilize communities in spatial environments, coexistence in unstructured environments remains unexplained. Here, using simulations and analytical models, we show that the opposing actions of antibiotic production and degradation enable coexistence even in well-mixed environments. Coexistence depends on three-way interactions in which an antibiotic-degrading species attenuates the inhibitory interactions between two other species. These interactions enable coexistence that is robust to substantial differences in inherent species growth rates and to invasion by ‘cheating’ species that cease to produce or degrade antibiotics. At least two antibiotics are required for stability, with greater numbers of antibiotics enabling more complex communities and diverse dynamic behaviours ranging from stable fixed points to limit cycles and chaos. Together, these results show how multi-species antibiotic interactions can generate ecological stability in both spatially structured and mixed microbial communities, suggesting strategies for engineering synthetic ecosystems and highlighting the importance of toxin production and degradation for microbial biodiversity.

  13. Relationship between in situ degradation kinetics and in vitro gas production fermentation using different mathematical models

    NARCIS (Netherlands)

    Rodrigues, M.A.M.; Cone, J.W.; Ferreira, L.M.M.; Blok, M.C.; Guedes, C.

    2009-01-01

    In vitro and in situ studies were conducted to evaluate the influence of different mathematical models, used to fit gas production profiles of 15 feedstuffs, on estimates of nylon bag organic matter (OM) degradation kinetics. The gas production data were fitted to Exponential, Logistic, Gompertz and

  14. In situ ruminal crude protein degradability of by-products from cereals, oilseeds and animal origin

    NARCIS (Netherlands)

    Habib, G.; Khan, N.A.; Ali, M.; Bezabih, M.

    2013-01-01

    The aim of this study was to establish a database on in situ ruminal crude protein (CP) degradability characteristics of by-products from cereal grains, oilseeds and animal origin commonly fed to ruminants in Pakistan and South Asian Countries. The oilseed by-products were soybean meal, sunflower me

  15. Conversion of waste polystyrene through catalytic degradation into valuable products

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Jasmin; Jan, Muhammad Rasul; Adnan [University of Peshawar, Peshawar (Pakistan)

    2014-08-15

    Waste expanded polystyrene (EPS) represents a source of valuable chemical products like styrene and other aromatics. The catalytic degradation was carried out in a batch reactor with a mixture of polystyrene (PS) and catalyst at 450 .deg. C for 30 min in case of Mg and at 400 .deg. C for 2 h both for MgO and MgCO{sub 3} catalysts. At optimum degradation conditions, EPS was degraded into 82.20±3.80 wt%, 91.60±0.20 wt% and 81.80±0.53 wt% liquid with Mg, MgO and MgCO{sub 3} catalysts, respectively. The liquid products obtained were separated into different fractions by fractional distillation. The liquid fractions obtained with three catalysts were compared, and characterized using GC-MS. Maximum conversion of EPS into styrene monomer (66.6 wt%) was achieved with Mg catalyst, and an increase in selectivity of compounds was also observed. The major fraction at 145 .deg. C showed the properties of styrene monomer. The results showed that among the catalysts used, Mg was found to be the most effective catalyst for selective conversion into styrene monomer as value added product.

  16. Photocatalytic degradation of polycyclic aromatic hydrocarbon benzo[a]pyrene by iron oxides and identification of degradation products.

    Science.gov (United States)

    Gupta, Himanshu; Gupta, Bina

    2015-11-01

    Photocatalytic decay profiles of polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (B[a]P) have been investigated on various synthesized iron oxides and on soil surfaces under a set of diverse conditions. Samples were analysed using the developed HPLC procedure. Results of the present study demonstrate fastest photodisintegration of B[a]P on goethite followed by haematite, magnetite, akaganeite and maghemite, respectively. The effect of soil pH, irradiation wavelength and iron oxide and oxalic acid dose on the degradation of B[a]P was evaluated. The studies revealed enhancement in photodegradation in the presence of oxalic acid due to the occurrence of fenton like reaction. The results showed faster B[a]P degradation under short wavelength UV radiation. Rate constants in acidic, neutral and alkaline soils under optimum dissipation conditions were 1.11×10(-2), 7.69×10(-3) and 9.97×10(-3) h(-1), respectively. The study indicates that iron oxides along with oxalic acid are effective photocatalyst for the remediation of benzo[a]pyrene contaminated soil surfaces. The degradation products of B[a]P in the soils of different pH in presence of goethite were identified and degradation pathways proposed. Peaks due to toxic metabolites such as diones, diols and epoxides disappear after 120 h in all the three soils.

  17. Treatment of low level radioactive liquid waste containing appreciable concentration of TBP degraded products.

    Science.gov (United States)

    Valsala, T P; Sonavane, M S; Kore, S G; Sonar, N L; De, Vaishali; Raghavendra, Y; Chattopadyaya, S; Dani, U; Kulkarni, Y; Changrani, R D

    2011-11-30

    The acidic and alkaline low level radioactive liquid waste (LLW) generated during the concentration of high level radioactive liquid waste (HLW) prior to vitrification and ion exchange treatment of intermediate level radioactive liquid waste (ILW), respectively are decontaminated by chemical co-precipitation before discharge to the environment. LLW stream generated from the ion exchange treatment of ILW contained high concentrations of carbonates, tributyl phosphate (TBP) degraded products and problematic radio nuclides like (106)Ru and (99)Tc. Presence of TBP degraded products was interfering with the co-precipitation process. In view of this a modified chemical treatment scheme was formulated for the treatment of this waste stream. By mixing the acidic LLW and alkaline LLW, the carbonates in the alkaline LLW were destroyed and the TBP degraded products got separated as a layer at the top of the vessel. By making use of the modified co-precipitation process the effluent stream (1-2 μCi/L) became dischargeable to the environment after appropriate dilution. Based on the lab scale studies about 250 m(3) of LLW was treated in the plant. The higher activity of the TBP degraded products separated was due to short lived (90)Y isotope. The cement waste product prepared using the TBP degraded product was having good chemical durability and compressive strength. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Studies on cellulose degradation by a Thermoactinimyces Sp

    Energy Technology Data Exchange (ETDEWEB)

    1977-04-01

    Progress in studies on the mechanism of cellulose degradation by Thermoactinomyces is reported. Two pure cellulosic substrates AVICEL and SOLKA FLOC were used in the experiments. A low substituted carboxymethylcellulose (Hercules 4M CMC), cellobiose, and glucose were also used as growth substrates. Results indicate that glucose is not inhibitory to growth up to 1% concetrations, and that cellobiose may not be a good inducer of the cellobiase enzyme activity. Production of biomass and soluble protein was found to be 50% greater on crystalline AVICEL than on the amorphous SOLKA FLOC, even though approximately the same amount and rate of cellulose degradation occurred. A model for cellulose digestion is presented. (JGB)

  19. [Ligninolytic enzyme production by white rot fungi during paraquat (herbicide) degradation].

    Science.gov (United States)

    Camacho-Morales, Reyna L; Gerardo-Gerardo, José Luis; Guillén Navarro, Karina; Sánchez, José E

    Paraquat is a widely used herbicide in agriculture. Its inappropriate use and wide distribution represents a serious pollution problem for soil and water. White rot fungi are capable of degrading pollutants having a similar structure to that of lignin, such as paraquat. This study evaluated the degradation effect of paraquat on the production of ligninolytic enzymes by white rot fungi isolated from the South of Mexico. Six fungal strains showed tolerance to the herbicide in solid culture. Three of the six evaluated strains showed levels of degradation of 32, 26 and 47% (Polyporus tricholoma, Cilindrobasidium laeve and Deconica citrispora, respectively) after twelve days of cultivation in the presence of the xenobiotic. An increase in laccase and manganese peroxidase (MnP) activities was detected in the strains showing the highest percentage of degradation. Experiments were done with enzyme extracts from the extracellular medium with the two strains showing more degradation potential and enzyme production. After 24hours of incubation, a degradation of 49% of the initial paraquat concentration was observed for D. citrispora. These results suggest that paraquat degradation can be attributed to the presence of extracellular enzymes from white rot fungi. In this work the first evidence of the biodegradation potential of D. citrispora and Cilindrobasidium leave is shown. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. Halotolerance, ligninase production and herbicide degradation ability of basidiomycetes strains

    Directory of Open Access Journals (Sweden)

    R.L. Arakaki

    2013-12-01

    Full Text Available Fungi have been recently recognized as organisms able to grow in presence of high salt concentration with halophilic and halotolerance properties and their ligninolytic enzyme complex have an unspecific action enabling their use to degradation of a number of xenobiotic compounds. In this work, both the effect of salt and polyols on growth of the basidiomycetes strains, on their ability to produce ligninolytic enzyme and diuron degradation were evaluated. Results showed that the presence of NaCl in the culture medium affected fungal specimens in different ways. Seven out of ten tested strains had growth inhibited by salt while Dacryopinax elegans SXS323, Polyporus sp MCA128 and Datronia stereoides MCA167 fungi exhibited higher biomass production in medium containing 0.5 and 0.6 mol.L-1 of NaCl, suggesting to be halotolerant. Polyols such as glycerol and mannitol added into the culture media improved the biomass and ligninases production by D. elegans but the fungus did not reveal consumption of these polyols from media. This fungus degraded diuron in medium control, in presence of NaCl as well as polyols, produced MnP, LiP and laccase.

  1. LC-MS characterization of valsartan degradation products and comparison with LC-PDA

    Directory of Open Access Journals (Sweden)

    Sumaia Araújo Pires

    2015-12-01

    Full Text Available abstract Valsartan was submitted to forced degradation under acid hydrolysis condition as prescribed by the ICH. Degraded sample aliquots were separated via HPLC using a Hypersil ODS (C18 column (250 x 4.6 mm i.d., 5 µm. Either photodiode array (PDA detection or mass spectrometry (MS full scan monitoring of HPLC runs were used. HPLC-PDA failed to indicate Valsartan degradation under forced acid degradation, showing an insignificant peak area variation and that Valsartan apparently remained pure. HPLC-MS using electrospray ionization (ESI and total ionic current (TIC monitoring did not reveal any peak variation either, but inspection of the ESI mass spectra showed the appearance of m/z 306 and m/z 352 ions for the same retention time as that of Valsartan (m/z 436. These ions were identified as being protonated molecules of two co-eluting degradation products formed by hydrolysis. These assignments were confirmed by ESI-MS/MS with direct infusion of the degraded samples. The results showed that the use of selective HPLC-MS is essential for monitoring Valsartan degradation. Efficient HPLC separation coupled to selective and structural diagnostic MS monitoring seems therefore mandatory for comprehensive drug degradation studies, particularly for new drugs and formulations, and for method development.

  2. In vitro degradation and total gas production of byproducts generated in the biodiesel production chain

    OpenAIRE

    2015-01-01

    This study aimed to evaluate the in vitro degradation and total gas production of different oil seed press cakes from a biodiesel production chain gas through the use of a semi-automatic technique of gas production in vitro. The treatments consisted of substituting elephant grass in increasing levels, 0%, 30, 50 and 70%, with the byproducts of Gossyypium hirsutum, Ricinus communis, Moringa oleifeira, Jatropha curcas and Helianthus annus. The oil seed press cakes of Moringa oleifeira had the h...

  3. Time extrapolation of radiolytic degradation product kinetics: the case of polyurethane; Extrapolation dans le temps des cinetiques de production des produits de degradation radiolytique: application a un polyurethane

    Energy Technology Data Exchange (ETDEWEB)

    Dannoux, A

    2007-02-15

    The prediction of the environmental impact of organic materials in nuclear waste geological storage needs knowledge of radiolytic degradation mechanisms and kinetics in aerobic and anaerobic conditions. In this framework, the effect of high doses (> MGy) and the variation of dose rate have to be considered. The material studied is a polyurethane composed of polyether soft segment and aromatic hard segments. Mechanisms were built on the analysis of material submitted to irradiations of simulation (high energy electrons and gamma radiation) by FTIR spectroscopy and gaseous and liquid degradation products by gas mass spectrometry and size exclusion chromatography. The electron paramagnetic resonance study of radical process and the determination of oxygen consumption and gas formation radiolytic yields allowed us to acquire kinetic data and to estimate dose rate and high doses effects. The polyurethane radio-oxidation mainly concerns soft segments and induced cross-linkings and production by scissions of oxidised compounds (esters, alcohols, carboxylic acids). The kinetic of radical termination is rapid and the dose rate effect is limited. After 10 MGy, branching and scission reactions are in equilibrium and low molecular weight products accumulate. At last, the degradation products release in water is influenced by the oxidation rate and the temperature. After 10 MGy, the soluble fraction is stabilised at 25%. The water soluble products identified by electro-spray ionisation mass spectrometry (alcohols, aldehydes, carboxylic acids) potentially formed complexes with radionuclides. (author)

  4. Is ascaridole a sensitizing degradation product in tea tree oil?

    NARCIS (Netherlands)

    Christoffers, Wietske Andrea; Blömeke, Brunhilde; Coenraads, Pieter Jan; Schuttelaar, Marielouise

    2014-01-01

    Background: Tea tree oil is a natural oil, which contains a-terpinene. Degradation of a-terpinene results in the endoperoxide ascaridole, which may cause allergic contact dermatitis. Objectives: To study the prevalence of sensitizations to ascaridole, the optimal patch test concentration, concomitan

  5. Identification and ecotoxicity of degradation products of chloroacetamide herbicides from UV-treatment of water.

    Science.gov (United States)

    Souissi, Yasmine; Bouchonnet, Stéphane; Bourcier, Sophie; Kusk, Kresten Ole; Sablier, Michel; Andersen, Henrik Rasmus

    2013-08-01

    The widespread occurrence of chlorinated herbicides and their degradation products in the aquatic environment raises health and environmental concerns. As a consequence pesticides, and to a lesser degree their degradation products, are monitored by authorities both in surface waters and drinking waters. In this study the formation of degradation products from ultraviolet (UV) treatment of the three chloroacetamide herbicides acetochlor, alachlor and metolachlor and their biological effects were investigated. UV treatment is mainly used for disinfection in water and wastewater treatments. First, the chemical structures of the main UV-degradation products were identified using gas chromatography coupled with mass spectrometry and liquid chromatography-mass spectrometry. The main transformation reactions were dechlorination, mono- and multi-hydroxylation and cyclizations. The ecotoxicity of the mixed photoproducts formed by UV-treatment until 90% of the original pesticide was converted was compared to the toxicity of chloroacetamides using the green alga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the marine bacteria Vibrio fischeri as test organisms. UV-treatment of alachlor and metolachlor increased the toxicity compared to the parent compounds while an equal toxicity was found for photolysis products of acetochlor. This suggests that toxic photodegradation products are generated from chloroacetamides under UV-treatment. An important perspective of this finding is that the photolysis products are at least as toxic as the parent compounds.

  6. Simple Spectrophotometric Methods for the Determination of Meloxicam in Presence of Its Degradation Products

    Institute of Scientific and Technical Information of China (English)

    Elham A. Taha

    2004-01-01

    Objective:To develope two simple and accurate spectrophotometric methods for the determination of meloxicam ( Ⅰ ) in presence of its degradation products, 5 - methyl - 2 - aminothiazole ( Ⅱ ) and benzothiazine carboxylic acid ( Ⅲ ). Method:Both methods are based on the formation of chelate complexes of the studied drug with uranyl acetate and ferric chloride at room temperature in a methanolic medium. Results:The resulting complexes are stable for 24 hrs and show absorption maxima at 406 nm and 580 nm for uranyl and ferric complexes respectiverecoveries of (99.44 ± 0. 48 ) % and (99. 42 ± 0. 45 ) %, and molar absorptivity of 4. 67 × 103 and 1. 029 × 103 respectively. Conclusion:Both methods are proved to be stability indicating as no interference was observed with the degradation products. The proposed methods were successfully applied to the determination of the drug in bulk powder, laboratory prepared mixtures containing different percentages of degradation products and pharmaceutical dosage forms.

  7. Evaluation of anaerobic degradation, biogas and digestate production of cereal silages using nylon-bags.

    Science.gov (United States)

    Negri, Marco; Bacenetti, Jacopo; Fiala, Marco; Bocchi, Stefano

    2016-06-01

    In this study, the degradation efficiency and the biogas and digestate production during anaerobic digestion were evaluated for the cereal silages most used to feed biogas plants. To this purpose, silages of: maize from the whole plant, maize from the ear, triticale and wheat were digested, inside of nylon bags, in laboratory scale digesters, for 75days. Overall, the test involved 288 nylon bags. After 75days of digestion, the maize ear silage shows the highest degradation efficiency (about 98%) while wheat silage the lowest (about 83%). The biogas production ranges from 438 to 852Nm(3)/t of dry matter for wheat and ear maize silage, respectively. For all the cereal silages, the degradation as well as the biogas production are faster at the beginning of the digestion time. Digestate mass, expressed as percentage of the fresh matter, ranges from 38% to 84% for wheat and maize ear silage, respectively.

  8. Mechanochemical degradation of tetrabromobisphenol A: Performance, products and pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kunlun; Huang, Jun; Zhang, Wang; Yu, Yunfei; Deng, Shubo [State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, POPs Research Center, Tsinghua University, Beijing 100084 (China); Yu, Gang, E-mail: yg-den@tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, POPs Research Center, Tsinghua University, Beijing 100084 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Fe + SiO{sub 2} shows better performance than CaO in mechanochemical destruction of TBBPA. Black-Right-Pointing-Pointer Nonhazardous inorganic carbon and soluble bromide were the final products. Black-Right-Pointing-Pointer Raman and FTIR imply the generation of inorganic carbon and removal of bromine atom. Black-Right-Pointing-Pointer Tri-BBPA, bi-BBPA, mono-BBPA, BPA were the main intermediates during ball milling. Black-Right-Pointing-Pointer The bromine was balanced and the degradation pathway was proposed. - Abstract: Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant (BFR), which has received more and more concerns due to its high lipophilicity, persistency and endocrine disrupting property in the environment. Considering the possible need for the safe disposal of TBBPA containing wastes in the future, the potential of mechanochemical (MC) destruction as a promising non-combustion technology was investigated in this study. TBBPA was co-ground with calcium oxide (CaO) or the mixture of iron powder and quartz sand (Fe + SiO{sub 2}) in a planetary ball mill at room temperature. The method of Fe + SiO{sub 2} destructed over 98% of initial TBBPA after 3 h and acquired 95% debromination rate after 5 h, which showed a better performance than the CaO method. Raman spectra and Fourier transform infrared spectroscopy (FTIR) demonstrated the generation of inorganic carbon with the disappearance of benzene ring and C-Br bond, indicating the carbonization and debromination process during mechanochemical reaction. LC-MS-MS screening showed that the intermediates of the treatment with Fe + SiO{sub 2} were tri-, bi-, mono-brominated BPA, BPA and other fragments. Finally all the intermediates were also destroyed after 5 h grinding. The bromine balance was calculated and a possible reaction pathway was proposed.

  9. Stability-indicating assay method for determination of actarit, its process related impurities and degradation products: Insight into stability profile and degradation pathways☆

    Directory of Open Access Journals (Sweden)

    A. Abiramasundari

    2014-12-01

    Full Text Available The stability of the drug actarit was studied under different stress conditions like hydrolysis (acid, alkaline and neutral, oxidation, photolysis and thermal degradation as recommended by International Conference on Harmonization (ICH guidelines. Drug was found to be unstable in acidic, basic and photolytic conditions and produced a common degradation product while oxidative stress condition produced three additional degradation products. Drug was impassive to neutral hydrolysis, dry thermal and accelerated stability conditions. Degradation products were identified, isolated and characterized by different spectroscopic analyses. Drug and the degradation products were synthesized by a new route using green chemistry. The chromatographic separation of the drug and its impurities was achieved in a phenomenex luna C18 column employing a step gradient elution by high performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC–PDA–MS. A specific and sensitive stability-indicating assay method for the simultaneous determination of the drug actarit, its process related impurities and degradation products was developed and validated.

  10. Enhanced enzymatic cellulose degradation by cellobiohydrolases via product removal

    DEFF Research Database (Denmark)

    Ahmadi Gavlighi, Hassan; Meyer, Anne S.; Mikkelsen, Jørn Dalgaard

    2013-01-01

    Product inhibition by cellobiose decreases the rate of enzymatic cellulose degradation. The optimal reaction conditions for two Emericella (Aspergillus) nidulans-derived cellobiohydrolases I and II produced in Pichia pastoris were identified as CBHI: 52 °C, pH 4.5–6.5, and CBHII: 46 °C, pH 4.......8. The optimum in a mixture of the two was 50 °C, pH 4.9. An almost fourfold increase in enzymatic hydrolysis yield was achieved with intermittent product removal of cellobiose with membrane filtration (2 kDa cut-off): The conversion of cotton cellulose after 72 h was ~19 % by weight, whereas the conversion...

  11. The role of peroxyl radicals in polyester degradation--a mass spectrometric product and kinetic study using the distonic radical ion approach.

    Science.gov (United States)

    Gervasoni, B D; Khairallah, G N; O'Hair, R A J; Wille, U

    2015-04-14

    Mass spectrometric techniques were used to obtain detailed insight into the reactions of peroxyl radicals with model systems of (damaged) polyesters. Using a distonic radical ion approach, it was shown that N-methylpyridinium peroxyl radical cations, Pyr(+)OO˙, do not react with non-activated C-H bonds typically present in polyesters that resist degradation. Structural damage in the polymer, for example small amounts of alkene moieties formed during the manufacturing process, is required to enable reaction with Pyr(+)OO˙, which proceeds with high preference through addition to the π system rather than via allylic hydrogen atom abstraction (kadd/kHAT > 20 for internal alkenes). This is due to the very fast and strongly exothermic subsequent fragmentation of the peroxyl-alkene radical adduct to epoxides and highly reactive Pyr(+)O˙, which both could promote further degradation of the polymer through non-radical and radical pathways. This work provides essential experimental support that the basic autoxidation mechanism is a too simplistic model to rationalize radical mediated degradation of polymers under ambient conditions.

  12. Teratogenicity of Ochratoxin A and the Degradation Product, Ochratoxin α, in the Zebrafish (Danio rerio) Embryo Model of Vertebrate Development

    OpenAIRE

    Mehreen Haq; Nelson Gonzalez; Keenan Mintz; Asha Jaja-Chimedza; Christopher Lawrence De Jesus; Christina Lydon; Welch, Aaron Z.; Berry, John P.

    2016-01-01

    Ochratoxins, and particularly ochratoxin A (OTA), are toxic fungal-derived contaminants of food and other agricultural products. Growing evidence supports the degradation of OTA by chemical, enzymatic and/or microbial means as a potential approach to remove this mycotoxin from food products. In particular, hydrolysis of OTA to ochratoxin α (OTα) and phenylalanine is the presumptive product of degradation in most cases. In the current study, we employed the zebrafish (Danio rerio) embryo, as a...

  13. Particulate and gas-phase products from the atmospheric degradation of chlorpyrifos and chlorpyrifos-oxon

    Science.gov (United States)

    Borrás, Esther; Ródenas, Milagros; Vázquez, Mónica; Vera, Teresa; Muñoz, Amalia

    2015-12-01

    The phosphorothioate structure is highly present in several pesticides. However, there is a lack of information about its degradation process in air and the secondary pollutants formed. Herein, the atmospheric reactions of chlorpyrifos, one of the most world-used insecticide, and its main degradation product - chlorpyrifos-oxon - are described. The photo-oxidation under the presence of NOx was studied in a large outdoor simulation chamber for both chlorpyrifos and chlorpyrifos-oxon, observing a rapid degradation (Half lifetime < 3.5 h for both compounds). Also, the photolysis reactions of both were studied. The formation of particulate matter (aerosol mass yield ranged 6-59%) and gaseous products were monitored. The chemical composition of minor products was studied, identifying 15 multi-oxygenated derivatives. The most abundant products were ring-retaining molecules such as 3,5,6-trichloropyridin-2-ol and ethyl 3,5,6-trichloropyridin-2-yl hydrogen phosphate. An atmospheric degradation mechanism has been amplified based on an oxidation started with OH-nucleophilic attack to Pdbnd S bond.

  14. Atrazine, triketone herbicides, and their degradation products in sediment, soil and surface water samples in Poland.

    Science.gov (United States)

    Barchanska, Hanna; Sajdak, Marcin; Szczypka, Kornelia; Swientek, Angelika; Tworek, Martyna; Kurek, Magdalena

    2017-01-01

    The aim of this study was to monitor the sediment, soil and surface water contamination with selected popular triketone herbicides (mesotrione (MES) and sulcotrione(SUL)), atrazine (ATR) classified as a possible carcinogen and endocrine disrupting chemical, as well as their degradation products, in Silesia (Poland). Seventeen sediment samples, 24 soil samples, and 64 surface water samples collected in 2014 were studied. After solid-liquid extraction (SLE) and solid phase extraction (SPE), analytes were determined by high-performance liquid chromatography (HPLC) with diode array detection (DAD). Ten years after the withdrawal from the use, ATR was not detected in any of the collected samples; however, its degradation products are still present in 41 % of sediment, 71 % of soil, and 8 % of surface water samples. SUL was determined in 85 % of soil samples; its degradation product (2-chloro-4-(methylosulfonyl) benzoic acid (CMBA)) was present in 43 % of soil samples. In 17 % of sediment samples, CMBA was detected. Triketones were detected occasionally in surface water samples. The chemometric analysis (clustering analysis (CA), single-factor analysis of variance (ANOVA), N-Way ANOVA) was applied to find relations between selected soil and sediment parameters and herbicides concentration. In neither of the studied cases a statistically significant relationship between the concentrations of examined herbicides, their degradation products and soil parameters (organic carbon (OC), pH) was observed.

  15. Estimating grass and grass silage degradation characteristics by in situ and in vitro gas production methods

    Directory of Open Access Journals (Sweden)

    Danijel Karolyi

    2010-01-01

    Full Text Available Fermentation characteristics of grass and grass silage at different maturities were studied using in situ and in vitro gas production methods. In situ data determined difference between grass and silage. Degradable fraction decreased as grass matured while the undegradable fraction increased. Rate of degradation (kd was slower for silage than fresh grass. Gas production method (GP data showed that fermentation of degradable fraction was different between stage of maturity in both grass and silage. Other data did not show any difference with the exception for the rate of GP of soluble and undegradable fraction. The in situ degradation characteristics were estimated from GP characteristics. The degradable and undegradable fractions could be estimated by multiple relationships. Using the three-phases model for gas production kd and fermentable organic matter could be estimated from the same parameters. The only in situ parameter that could not be estimated with GP parameters was the soluble fraction. The GP method and the three phases model provided to be an alternative to the in situ method for animal feed evaluations.

  16. Photochemical, thermal, biological and long-term degradation of celecoxib in river water. Degradation products and adsorption to sediment.

    Science.gov (United States)

    Jiménez, Juan J; Pardo, Rafael; Sánchez, María I; Muñoz, Beatriz E

    2017-08-19

    Celecoxib is an anti-inflammatory drug with antibacterial activity whose fate in surface water is unknown. Thus, some assays have been conducted under forced biological, photochemical and thermal conditions, and non-forced conditions, to establish its persistence and degradation products in river water. The results suggest that celecoxib dissolved in river water is not biologically degraded while it is minimally altered after its exposure to sunlight or high temperature (70°C). Only the irradiation at 254nm promotes its complete degradation. Celecoxib is degraded about 3%, in 36 weeks, when water was kept at room temperature and the exposure to sunlight was partially limited as it happens inside a body of water. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction; eleven degradation products were detected and the structures of nine of them were unequivocally proposed from the molecular formulae and fragmentation observed in high-resolution tandem mass spectra. The long-term transformation products under non-forced conditions were 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonic acid, 4-[1-(4-sulfoaminephenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl]benzoic acid and a hydroxylated derivative. The degradation over time in presence of sediment was monitored, being slightly higher, about 4%. The adsorption equilibrium constants of celecoxib and degradation products on river sediment were estimated. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Vascular responsiveness to dimethylaminoethyl methacrylate and its degradation products.

    Science.gov (United States)

    Abebe, Worku; Maddux, William F; Schuster, George S; Lewis, Jill B

    2003-07-01

    The increasing use of acrylate-based resins in dentistry has raised questions about the biocompatibility of these substances with oral tissues. The focus of the present investigation was to assess the responsiveness of blood vessels to the resin polymerization accelerating agent dimethylaminoethyl methacrylate (DMAEMA) and its degradation products dimethylethanolamine (DME) and methacrylic acid (MAA), using the rat aortic ring preparation as a tissue model. DMAEMA induced concentration-dependent relaxation of norepinephrine (NE)-contracted aortic rings with and without endothelium. N-nitro-L-arginine methyl ester (L-NAME) selectively inhibited the endothelium-dependent relaxation induced by DMAEMA, suggesting the release of nitric oxide from the endothelium by DMAEMA. Both indomethacin and glybenclamide attenuated the vasorelaxation elicited by DMAEMA in the presence as well as in the absence of endothelium, providing evidence for the role of vasorelaxant prostanoid(s) and K(ATP) channel activation in the responses observed. On the other hand, while MAA was without any apparent effect on the rat aorta, DMAEMA at high and DME at relatively low concentrations caused contraction of the tissues with and without endothelium in the absence of NE. The DME-induced contraction was inhibited by indomethacin, suggesting the involvement of contractile arachidonic acid metabolite(s) in the action of DME. This observation was supported by the findings of increased thromboxane A(2) (TXA(2)) production in aortic rings incubated with DME. Taken together, the data suggest that both DMAEMA and its degradation product, DME, are vasoactive, inducing vasorelaxation and contraction by various mechanisms that may involve the release of nitric oxide from the endothelium, the activation of smooth muscle K(ATP) channels, and the generation of vasorelaxant prostanoid(s) and TXA(2). These effects may play a role in tissue homeostasis and certain adverse conditions associated with the use of

  18. Photocatalytic degradation of organic pollutants with simultaneous production of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Patsoura, Alexia; Kondarides, Dimitris I.; Verykios, Xenophon E. [Department of Chemical Engineering, University of Patras, GR-26504 Patras (Greece)

    2007-06-30

    The photocatalytic degradation of a number of organic compounds in solution, including alcohols and organic acids, has been investigated under unaerated conditions with the use of Pt/TiO{sub 2} photocatalyst and solar or UV irradiation. It has been found that production of CO{sub 2} is in all cases accompanied by evolution of hydrogen, the production rate of which is significantly enhanced, compared with that obtained in the absence of organic additives in solution. Results are explained by considering that organic compounds act as sacrificial electron donors, which become progressively oxidized toward CO{sub 2} by consuming photogenerated holes and/or oxygen. This results in decreased rates of electron-hole recombination and oxygen-hydrogen back reaction and, concomitantly, in increased H{sub 2}-production rates. The rate of photoinduced hydrogen production depends strongly on the concentration of the sacrificial agent employed and to a lesser extent on solution pH and temperature. When complete mineralization of the sacrificial agent is achieved, photogenerated oxygen can no longer be removed from the photocatalyst surface and the H{sub 2}-production rate drops to steady-state values, comparable to those obtained in the absence of the organic compound in solution. The amounts of carbon dioxide and 'additional' hydrogen produced depend on the nature of the organic additive and are directly proportional to its initial concentration in solution. Quantification of results shows that the overall process may be described as 'photoinduced reforming of organic compounds at room temperature'. It is concluded that mineralization of organic pollutants such as alcohols and organic acids, which are common waste products of biomass processing industries, can be achieved with simultaneous production of H{sub 2} fuel. The process may provide an efficient and cost effective method for cleaning up waste streams. (author)

  19. A PERITONEAL DIALYSIS REGIMEN LOW IN GLUCOSE AND GLUCOSE DEGRADATION PRODUCTS RESULTS IN INCREASED CANCER ANTIGEN 125 AND PERITONEAL ACTIVATION

    NARCIS (Netherlands)

    le Poole, Caatje Y.; Welten, Angelique G. A.; ter Wee, Piet M.; Paauw, Nanne J.; Djorai, Amina N.; Valentijn, Rob M.; Beelen, Robert H. J.; van den Born, Jacob; van Ittersum, Frans J.

    2012-01-01

    Background: Glucose and glucose degradation products (GDPs) in peritoneal dialysis fluids (PDFs) are both thought to mediate progressive peritoneal worsening. Methods: In a multicenter, prospective, randomized crossover study, incident continuous ambulatory peritoneal dialysis patients were treated

  20. Serological studies on chloridazon-degrading bacteria.

    Science.gov (United States)

    Layh, G; Böhm, R; Eberspächer, J; Lingens, F

    1983-01-01

    Agglutination tests and immunofluorescence tests with antisera against four strains of chloridazon-degrading bacteria revealed the serological uniformity of a group of 22 chloridazon-degrading bacterial strains. No serological relationship could be found between chloridazon-degrading bacteria and representatives of other Gram-negative bacteria. This was demonstrated by agglutination tests, including testing of the antiserum against Acinetobacter calcoaceticus, and by immunofluorescence tests, including testing of the sera against Pseudomonas and Acinetobacter strains. The tests were performed with 31 representatives of different Gram-negative bacteria, and with 22 strains of chloridazon-degrading bacteria as antigens. Differences in the extent of agglutination reactions and antibody titres among chloridazon-degrading bacterial strains together with cross-adsorption xperiments, suggest a rough classification of chloridazon-degrading bacteria into two subgroups. On the basis of immunofluorescence data, a linkage-map was worked out to represent serological relationships in the group of chloridazon-degrading strains.

  1. Degradation of the pharmaceuticals diclofenac and sulfamethoxazole and their transformation products under controlled environmental conditions.

    Science.gov (United States)

    Poirier-Larabie, S; Segura, P A; Gagnon, C

    2016-07-01

    Contamination of the aquatic environment by pharmaceuticals via urban effluents is well known. Several classes of drugs have been identified in waterways surrounding these effluents in the last 15years. To better understand the fate of pharmaceuticals in ecosystems, degradation processes need to be investigated and transformation products must be identified. Thus, this study presents the first comparative study between three different natural environmental conditions: photolysis and biodegradation in aerobic and anaerobic conditions both in the dark of diclofenac and sulfamethoxazole, two common drugs present in significant amounts in impacted surface waters. Results indicated that degradation kinetics differed depending on the process and the type of drug and the observed transformation products also differed among these exposure conditions. Diclofenac was nearly degraded by photolysis after 4days, while its concentration only decreased by 42% after 57days of exposure to bacteria in aerobic media and barely 1% in anaerobic media. For sulfamethoxazole, 84% of the initial concentration was still present after 11days of exposure to light, while biodegradation decreased its concentration by 33% after 58days of exposure under aerobic conditions and 5% after 70days of anaerobic exposure. In addition, several transformation products were observed and persisted over time while others degraded in turn. For diclofenac, chlorine atoms were lost primarily in the photolysis, while a redox reaction was promoted by biodegradation under aerobic conditions. For sulfamethoxazole, isomerization was favored by photolysis while a redox reaction was also favored by the biodegradation under aerobic conditions. To summarize this study points out the occurrence of different transformation products under variable degradation conditions and demonstrates that specific functional groups are involved in the tested natural attenuation processes. Given the complexity of environmental samples

  2. Bacteria-based polythene degradation products: GC-MS analysis and toxicity testing.

    Science.gov (United States)

    Shahnawaz, Mohd; Sangale, Manisha K; Ade, Avinash B

    2016-06-01

    Polythene degradation leads to the production of various by-products depending upon the type of degradation process. The polythene degradation products (PEDP) in the culture supernatant of the two bacteria (Lysinibacillus fusiformis strain VASB14/WL and Bacillus cereus strain VASB1/TS) were analyzed with GC-MS technique. The major by-products in the PEDP in the culture supernatant of L. fusiformis strain VASB14/WL (1,2,3,4 tetra methyl benzene) and B. cereus strain VASB1/TS (1,2,3 trimethyl benzene, 1 ethyl 3,5-dimethyl benzene, 1,4 di methyl 2 ethyl benzene, and dibutyl phthalate) dissolved in diethyl ether were recorded. To assess the environmental applicability of polythene degradation using L. fusiformis strain VASB14/WL and B. cereus strain VASB1/TS at in vitro level. The effect of PEDP produced after 2 months of regular shaking at room temperature on both plants and animal system was studied. No significant decrease in the percent seed germination was recorded with the PEDP of both the bacteria. PEDP produced by L. fusiformis strain VASB14/WL did not report any significant change in germination index (GI) at 10 and 25 %, but least GI (39.66 ± 13.94) was documented at 50 % concentration of PEDP. Highest elongation inhibition rate (53.83 ± 15.71) of Sorghum was also recorded with L. fusiformis and at the same concentration.

  3. Production of degradable polymers from food-waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, S.P.: Coleman, R.D.; Bonsignore, P.V.; Moon, S.H.

    1992-01-01

    In the United States, billions of pounds of cheese whey permeate and approximately 10 billion pounds of potatoes processed each year are typically discarded or sold as cattle feed at $3{endash}6/ton; moreover, the transportation required for these means of disposal can be expensive. As a potential solution to this economic and environmental problem, Argonne National Laboratory is developing technology that: Biologically converts existing food-processing waste streams into lactic acid and uses lactic acid for making environmentally safe, degradable polylactic acid (PLA) and modified PLA plastics and coatings. An Argonne process for biologically converting high-carbohydrate food waste will not only help to solve a waste problem for the food industry, but will also save energy and be economically attractive. Although the initial substrate for Argonne's process development is potato by-product, the process can be adapted to convert other food wastes, as well as corn starch, to lactic acid. Proprietary technology for biologically converting greater than 90% of the starch in potato wastes to glucose has been developed. Glucose and other products of starch hydrolysis are subsequently fermented by bacteria that produce lactic acid. The lactic acid is recovered, concentrated, and further purified to a polymer-grade product.

  4. Production of degradable polymers from food-waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, S.P.: Coleman, R.D.; Bonsignore, P.V.; Moon, S.H.

    1992-07-01

    In the United States, billions of pounds of cheese whey permeate and approximately 10 billion pounds of potatoes processed each year are typically discarded or sold as cattle feed at $3{endash}6/ton; moreover, the transportation required for these means of disposal can be expensive. As a potential solution to this economic and environmental problem, Argonne National Laboratory is developing technology that: Biologically converts existing food-processing waste streams into lactic acid and uses lactic acid for making environmentally safe, degradable polylactic acid (PLA) and modified PLA plastics and coatings. An Argonne process for biologically converting high-carbohydrate food waste will not only help to solve a waste problem for the food industry, but will also save energy and be economically attractive. Although the initial substrate for Argonne`s process development is potato by-product, the process can be adapted to convert other food wastes, as well as corn starch, to lactic acid. Proprietary technology for biologically converting greater than 90% of the starch in potato wastes to glucose has been developed. Glucose and other products of starch hydrolysis are subsequently fermented by bacteria that produce lactic acid. The lactic acid is recovered, concentrated, and further purified to a polymer-grade product.

  5. Production and characterization of esterase in Lantinus tigrinus for degradation of polystyrene.

    Science.gov (United States)

    Tahir, Lubna; Ishtiaq Ali, Muhammad; Zia, Muhammad; Atiq, Naima; Hasan, Fariha; Ahmed, Safia

    2013-01-01

    Polystyrene is considered stable to biological degradation. Lantinus tigrinus isolated from wood sample produced esterase in growth medium under normal conditions. However, acidic medium, 37 degrees C temperature, presence of tween 80; and urea and yeast extract in mineral salt medium enhance the production of esterase and specific activity. Purified esterase was active at broad pH range and 45 degrees C. FTIR analysis confirmed that esterase produced by Lantinus tigrinus effectively degraded polystyrene film and broke macromolecules down to non-toxic molecules. This study concludes that the presence of Lantinus tigrinus at dumping sites can be exploited for waste management containing high molecular weight synthetic polymers.

  6. Durability Improvements Through Degradation Mechanism Studies

    Energy Technology Data Exchange (ETDEWEB)

    Borup, Rodney L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mukundan, Rangachary [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Spernjak, Dusan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baker, Andrew M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lujan, Roger W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Langlois, David Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ahluwalia, Rajesh [Argonne National Lab. (ANL), Argonne, IL (United States); Papadia, D. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Weber, Adam Z. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kusoglu, Ahmet [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shi, Shouwnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); More, K. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Grot, Steve [Ion Power, New Castle, DE (United States)

    2015-08-03

    The durability of polymer electrolyte membrane (PEM) fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. By investigating cell component degradation modes and defining the fundamental degradation mechanisms of components and component interactions, new materials can be designed to improve durability. To achieve a deeper understanding of PEM fuel cell durability and component degradation mechanisms, we utilize a multi-institutional and multi-disciplinary team with significant experience investigating these phenomena.

  7. Relationship between lignin degradation and production of reduced oxygen species by Phanerochaete chrysosporium

    Energy Technology Data Exchange (ETDEWEB)

    Faison, B.D.; Kirk, T.K.

    1983-11-01

    The relationship between the production of reduced oxygen species, hydrogen peroxide (H/sub 2/O/sub 2/), superoxide (O/sub 2//sup -/), and hydroxyl radical (.OH), and the oxidation of synthetic lignin to CO/sub 2/ was studied in whole cultures of the white-rot fungus Phanerochaete chrysosporium Burds. The kinetics of the synthesis of H/sub 2/O/sub 2/ coincided with the appearance of the ligninolytic system; also, H/sub 2/O/sub 2/ production was markedly enhanced by growth under 100% O/sub 2/, mimicing the increase in ligninolytic activity characteristic of cultures grown under elevated oxygen tension. Lignin degradation by whole cultures was inhibited by a specific H/sub 2/O/sub 2/ scavenger, catalase, implying a role for H/sub 2/O/sub 2/ in the degradative process. Superoxide dismutase also inhibited lignin degradation, suggesting that O/sub 2//sup -/ is also involved in the breakdown of lignin. The production of .OH was assayed in whole cultures by a benzoate decarboxylation assay. Neither the kinetics of .OH synthesis nor the final activity of its producing system obtained under 100% O/sub 2/ correlated with that of the lignin-degrading system. However, lignin degradation was inhibited by compounds which react with .OH. It is concluded that H/sub 2/O/sub 2/, and perhaps O/sub 2//sup -/, are involved in lignin degradation; because these species are relatively unreactive per se, their role must be indirect. Conclusions about a role for .OH in ligninolysis could not be reached. (Refs. 28).

  8. Persistence of alprazolam in river water according to forced and non-forced degradation assays: adsorption to sediment and long-term degradation products.

    Science.gov (United States)

    Jiménez, Juan J; Sánchez, María I; Muñoz, Beatriz E; Pardo, Rafael

    2017-08-01

    Alprazolam is a pharmaceutical compound that it is detected in surface waters. Some degradation studies in aqueous solutions and pharmaceutical products are available, but there is no reliable information about its stability in river water. Here, assays have been conducted under forced biological, photochemical, and thermal conditions, and under non-forced conditions, to estimate the fate of alprazolam in river water and know its degradation products. The forced assays indicated that the biological and photochemical degradation of alprazolam was negligible; heating at 70°C for a long time barely affected it. The degradation of alprazolam in river water at 100 μg/L was about 5% after 36 weeks, keeping the water under a natural day-night cycle at room temperature and limiting partially the exposure to sunlight as happens inside a body of water; no change in concentration was observed when the monitoring was performed at 2 μg/L. The results suggest the persistence of alprazolam in surface water and a possible accumulation over time. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction; nine degradation products were found and the structures for most of them were proposed from the molecular formulae and fragmentation observed in high-resolution tandem mass spectra. (5-chloro-2-(3-methyl-4H-1,2,4-triazol-4-yl)phenyl)(phenyl)methanol was the main long-term transformation product in conditions that simulate those in a mass of water. The degradation rate in presence of sediment was equally very low under non-forced conditions; adsorption coefficients of alprazolam and major degradation products were calculated. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. The Study of the Microbes Degraded Polystyrene

    Directory of Open Access Journals (Sweden)

    Zhi-Long Tang

    2017-01-01

    Full Text Available Under the observation that Tenebrio molitor and Zophobas morio could eat polystyrene (PS, we setup the platform to screen the gut microbes of these two worms. To take advantage of that Tenebrio molitor and Zophobas morio can eat and digest polystyrene as its diet, we analyzed these special microbes with PS plate and PS turbidity system with time courses. There were two strains TM1 and ZM1 which isolated from Tenebrio molitor and Zophobas morio, and were identified by 16S rDNA sequencing. The results showed that TM1 and ZM1 were cocci-like and short rod shape Gram-negative bacteria under microscope. The PS plate and turbidity assay showed that TM1 and ZM1 could utilize polystyrene as their carbon sources. The further study of PS degraded enzyme and cloning warrants our attention that this platform will be an excellent tools to explore and solve this problem.

  10. Biodegradation of Leonardite by an alkali-producing bacterial community and characterization of the degraded products.

    Science.gov (United States)

    Gao, Tong-Guo; Jiang, Feng; Yang, Jin-Shui; Li, Bao-Zhen; Yuan, Hong-Li

    2012-03-01

    In this study, three bacterial communities were obtained from 12 Leonardite samples with the aim of identifying a clean, effective, and economic technique for the dissolution of Leonardite, a type of low-grade coal, in the production of humic acid (HA). The biodegradation ability and characteristics of the degraded products of the most effective bacterial community (MCSL-2), which degraded 50% of the Leonardite within 21 days, were further investigated. Analyses of elemental composition, (13)C NMR, and Fourier transform infrared revealed that the contents of C, O, and aliphatic carbon were similar in biodegraded humic acid (bHA) and chemically (alkali) extracted humic acid (cHA). However, the N and carboxyl carbon contents of bHA was higher than that of cHA. Furthermore, a positive correlation was identified between the degradation efficiency and the increasing pH of the culture medium, while increases of manganese peroxidase and esterase activities were also observed. These data demonstrated that both alkali production and enzyme reactions were involved in Leonardite solubilization by MCSL-2, although the former mechanism predominated. No fungus was observed by microscopy. Only four bacterial phylotypes were recognized, and Bacillus licheniformis-related bacteria were identified as the main group in MCSL-2 by analysis of amplified 16S rRNA genes, thus demonstrating that Leonardite degradation ability has a limited distribution in bacteria. Hormone-like bioactivities of bHA were also detected. In this study, a bacterial community capable of Leonardite degradation was identified and the products characterized. These data implicate the use of such bacteria for the exploitation of Leonardite as a biofertilizer.

  11. [Degradation Kinetics and Formation of Disinfection By-products During Linuron Chlorination in Drinking Water].

    Science.gov (United States)

    Ling, Xiao; Hu, Chen-yan; Cheng, Ming; Gu, Jian

    2015-05-01

    Chlorination degradation of linuron was studied using the common disinfectant sodium hypochlorite, the effects of chlorine dosage, pH value, bromine ion concentrationand temperature were systematically investigated, and the formation characteristics of disinfection by-products (DBPs) during the chlorination reaction was analyzed. The results showed that the chlorination degradation kinetics of linuron by sodium hypochlorite could be well described by the second-order kinetic model. Moreover, pH values had a great impact on the degradation reaction, and the rate constant reached the maximum level at pH 7, and the base elementary reaction rate constants of HOCl and OCl- with linuron were 4.84 x 10(2) L · (mol · h)(-1) and 3.80 x 10(2) L · (mol · h)(-1), respectively. The reaction rate decreased with the addition of bromide ion and increased with increasing temperature. Furthermore, many kinds of disinfection by- products were produced during the chlorination degradation of linuron, including CF, DCAN, TCNM and halogen acetone. Under conditions of different solution pH and different bromide ion concentrations, there would be significant difference in the types and concentrations of disinfection by-products.

  12. Characterization of radiolytically generated degradation products in the strip section of a TRUEX flowsheet

    Energy Technology Data Exchange (ETDEWEB)

    Dean R. Peterman; Lonnie G. Olson; Gary S. Groenewold; Rocklan G. McDowell; Richard D. Tillotson; Jack D. Law

    2013-08-01

    This report presents a summary of the work performed to meet the FCRD level 2 milestone M3FT-13IN0302053, “Identification of TRUEX Strip Degradation.” The INL radiolysis test loop has been used to identify radiolytically generated degradation products in the strip section of the TRUEX flowsheet. These data were used to evaluate impact of the formation of radiolytic degradation products in the strip section upon the efficacy of the TRUEX flowsheet for the recovery of trivalent actinides and lanthanides from acidic solution. The nominal composition of the TRUEX solvent used in this study is 0.2 M CMPO and 1.4 M TBP dissolved in n-dodecane and the nominal composition of the TRUEX strip solution is 1.5 M lactic acid and 0.050 M diethylenetriaminepentaacetic acid. Gamma irradiation of a mixture of TRUEX process solvent and stripping solution in the test loop does not adversely impact flowsheet performance as measured by stripping americium ratios. The observed increase in americium stripping distribution ratios with increasing absorbed dose indicates the radiolytic production of organic soluble degradation compounds.

  13. Identification, characterization and in silico ADMET prediction of Roflumilast degradation products.

    Science.gov (United States)

    Pinheiro, Mariana S; Viana, Gil M; Vieira, Bárbara de A Abrahim; de Souza, Alessandra Mendonça Teles; Rodrigues, Carlos Rangel; Marins, Rita de Cássia E E; Cabral, Lúcio M; de Sousa, Valéria P

    2017-05-10

    The present study reports the degradation behavior of roflumilast (RFL), a new drug developed for the treatment of chronic obstructive pulmonary disease. The degradation of RFL was tested under various stress conditions as per the guidelines of the International Conference on Harmonization. The degradation products (DPs) of RFL were identified, characterized and in silico predictions were made of their pharmacokinetic properties, absorption, distribution, metabolism, excretion and toxicity (ADMET). RFL was subjected to various stress conditions including photodegradation, alkaline and acidic hydrolysis, oxidative and metallic degradation. After analysis by HPLC-DAD, the DPs were isolated by preparative TLC and characterized by high resolution mass spectrometry (HRMS), (1)H NMR, (13)C NMR and infrared (IR) spectroscopy. RFL tablets were prepared by the addition of solid stressing substances such as excipients and storage in an accelerated stability chamber (40°C; 75% r.h.) for sixteen months. Resulting DPs from the tablets were analyzed by UFLC-QTOF. The most drastic degradation conditions for RFL were 5M NaOH(aq), 6M HCl(aq), 7.5% v/v peracetic acid, which resulted in the isolation of four DPs. However, milder degradation conditions (1M NaOH(aq) and photolysis) generated six DPs (DP-1, 2, 3, 5, 7 and 8), and are more similar to the actual conditions the drug will be exposed. For tablets containing RFL exposed to an alkaline reagent, two DPs were formed: DP-1 and DP-11. Whereas RFL-containing tablets exposed to acid and oxidizing agents, formed one product DP-11. Forced degradation of RFL led to the formation of eleven DPs, seven of which have never been previously reported. RFL is stable under metallic stress and it is relatively stable during photodegradation testing. The UFLC-QTOF methodology detected a greater number of DPs that formed during the stress conditions tested when compared to the HPLC-DAD methodology. In silico prediction of the ADMET properties of

  14. Stress Degradation Behavior of Atorvastatin Calcium and Development of a Suitable Stability-Indicating LC Method for the Determination of Atorvastatin, its Related Impurities, and its Degradation Products.

    Science.gov (United States)

    Vukkum, Pallavi; Moses Babu, J; Muralikrishna, R

    2013-01-01

    A rapid, reversed-phase liquid chromatographic method was developed for the quantitative determination of Atorvastatin calcium, its related substances (12 impurities), and degradation impurities in bulk drugs. The chromatographic separation was achieved on a Zorbax Bonus-RP column by employing a gradient elution with water-acetonitrile-trifluoroacetic acid as the mobile phase in a shorter run time of 25 min. The flow rate was 1.0 mL/min and the detection wavelength was 245 nm. The drug substance was subjected to stress studies such as hydrolysis, oxidation, photolysis, and thermal degradation, and considerable degradation was observed in acidic hydrolysis, oxidative, thermal, and photolytic stress conditions. The formed degradation products were reported and were well-resolved from the Atorvastatin and its related substances. The stressed samples were quantified against a qualified reference standard and the mass balance was found to be close to 99.5% (w/w) when the response of the degradant was considered to be equal to the analyte (i.e. Atorvastatin), which demonstrates the stability-indicating capability of the method. The method was validated in agreement with ICH requirements. The method developed here was single and shorter (25 min method for the determination of all 12 related impurities of Atorvastatin and its degradation products), with clearly better resolution and higher sensitivity than the European (85 min method for the determination of six impurities) and United States pharmacopeia (115 min and 55 min, two different methods for the determination of six related substances).

  15. Optimization of crude oil degradation by Dietzia cinnamea KA1, capable of biosurfactant production.

    Science.gov (United States)

    Kavynifard, Amirarsalan; Ebrahimipour, Gholamhossein; Ghasempour, Alireza

    2016-05-01

    The aim of this study was isolation and characterization of a crude oil degrader and biosurfactant-producing bacterium, along with optimization of conditions for crude oil degradation. Among 11 isolates, 5 were able to emulsify crude oil in Minimal Salt Medium (MSM) among which one isolate, named KA1, showed the highest potency for growth rate and biodegradation. The isolate was identified as Dietzia cinnamea KA1 using morphological and biochemical characteristics and 16S rRNA gene sequencing. The optimal conditions were 510 mM NaCl, pH 9.0, 35 °C, and minimal requirement of 46.5 mM NH4 Cl and 2.10 mM NaH2 PO4 . Gravimetric test and Gas chromatography-Mass spectroscopy technique (GC-MS) showed that Dietzia cinnamea KA1 was able to utilize and degrade 95.7% of the crude oil after 5 days, under the optimal conditions. The isolate was able to grow and produce biosurfactant when cultured in MSM supplemented with crude oil, glycerol or whey as the sole carbon sources, but bacterial growth was occurred using molasses with no biosurfactant production. This is the first report of biosurfactant production by D. cinnamea using crude oil, glycerol and whey and the first study to report a species of Dietzia degrading a wide range of hydrocarbons in a short time.

  16. In vitro degradation and gas production of brachiaria grass with levels of biodiesel byproducts

    Directory of Open Access Journals (Sweden)

    Juliana Marques Freire

    2017-04-01

    Full Text Available This study aimed to evaluate the in vitro degradability and gas production in diets containing byproducts from the national biodiesel industry (castor bean, canola, forage radish and black sunflower replacing Brachiaria grass in four levels (0, 30, 50 and 70%. The inoculum for in vitro incubation was obtained from three fistulated Holstein cows. The experimental design was 4 x 4 factorial completely randomized experimental design consisting of four byproducts and four levels. All byproducts studied had a significant effect (p < 0.05 on in vitro digestibility. The castor bean byproducts promoted the lowest cumulative gas production at the end of 48 hours incubation. Regarding digestibility, the byproducts of canola and radish at 70% level did not affect the degradability of dry matter.

  17. Biodegradation of the alkaline cellulose degradation products generated during radioactive waste disposal.

    Science.gov (United States)

    Rout, Simon P; Radford, Jessica; Laws, Andrew P; Sweeney, Francis; Elmekawy, Ahmed; Gillie, Lisa J; Humphreys, Paul N

    2014-01-01

    The anoxic, alkaline hydrolysis of cellulosic materials generates a range of cellulose degradation products (CDP) including α and β forms of isosaccharinic acid (ISA) and is expected to occur in radioactive waste disposal sites receiving intermediate level radioactive wastes. The generation of ISA's is of particular relevance to the disposal of these wastes since they are able to form complexes with radioelements such as Pu enhancing their migration. This study demonstrates that microbial communities present in near-surface anoxic sediments are able to degrade CDP including both forms of ISA via iron reduction, sulphate reduction and methanogenesis, without any prior exposure to these substrates. No significant difference (n = 6, p = 0.118) in α and β ISA degradation rates were seen under either iron reducing, sulphate reducing or methanogenic conditions, giving an overall mean degradation rate of 4.7 × 10(-2) hr(-1) (SE ± 2.9 × 10(-3)). These results suggest that a radioactive waste disposal site is likely to be colonised by organisms able to degrade CDP and associated ISA's during the construction and operational phase of the facility.

  18. Biodegradation of the alkaline cellulose degradation products generated during radioactive waste disposal.

    Directory of Open Access Journals (Sweden)

    Simon P Rout

    Full Text Available The anoxic, alkaline hydrolysis of cellulosic materials generates a range of cellulose degradation products (CDP including α and β forms of isosaccharinic acid (ISA and is expected to occur in radioactive waste disposal sites receiving intermediate level radioactive wastes. The generation of ISA's is of particular relevance to the disposal of these wastes since they are able to form complexes with radioelements such as Pu enhancing their migration. This study demonstrates that microbial communities present in near-surface anoxic sediments are able to degrade CDP including both forms of ISA via iron reduction, sulphate reduction and methanogenesis, without any prior exposure to these substrates. No significant difference (n = 6, p = 0.118 in α and β ISA degradation rates were seen under either iron reducing, sulphate reducing or methanogenic conditions, giving an overall mean degradation rate of 4.7 × 10(-2 hr(-1 (SE ± 2.9 × 10(-3. These results suggest that a radioactive waste disposal site is likely to be colonised by organisms able to degrade CDP and associated ISA's during the construction and operational phase of the facility.

  19. Mapping intermediate degradation products of poly(lactic-co-glycolic acid) in vitro.

    Science.gov (United States)

    Li, Jian; Nemes, Peter; Guo, Ji

    2017-05-17

    There is widespread interest in using absorbable polymers, such as poly(lactic-co-glycolic acid) (PLGA), as components in the design and manufacture of new-generation drug eluting stents (DES). PLGA undergoes hydrolysis to progressively degrade through intermediate chemical entities to simple organic acids that are ultimately absorbed by the human body. Understanding the composition and structure of these intermediate degradation products is critical not only to elucidate polymer degradation pathways accurately, but also to assess the safety and performance of absorbable cardiovascular implants. However, analytical approaches to determining the intermediate degradation products have yet to be established and evaluated in a standard or regulatory setting. Hence, we developed a methodology using electrospray ionization mass spectrometry to qualitatively and quantitatively describe intermediate degradation products generated in vitro from two PLGA formulations commonly used in DES. Furthermore, we assessed the temporal evolution of these degradation products using time-lapse experiments. Our data demonstrated that PLGA degradation products via heterogeneous cleavage of ester bonds are modulated by multiple intrinsic and environmental factors, including polymer chemical composition, degradants solubility in water, and polymer synthesis process. We anticipate the methodologies and outcomes presented in this work will elevate the mechanistic understanding of comprehensive degradation profiles of absorbable polymeric devices, and facilitate the design and regulation of cardiovascular implants by supporting the assessments of the associated biological response to degradation products. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  20. Comparison of N-nitrosodiethylamine degradation in water by UV irradiation and UV/O3: efficiency, product and mechanism.

    Science.gov (United States)

    Xu, Bingbing; Chen, Zhonglin; Qi, Fei; Ma, Jun; Wu, Fengchang

    2010-07-15

    N-nitrosodiethylamine (NDEA) is a member of nitrosamines, which is strong carcinogenic. In order to explore an effective treatment method for NDEA removal from water, sole UV irradiation and UV/O(3) were carried out in this study. The removal efficiency, degradation products and pathways were compared between those two processes. Results showed that NDEA removal efficiency achieved 99% within 15 min by both UV and UV/O(3). Degradation reaction well followed pseudo-first-order kinetics. Water pH had different effect on NDEA degradation in those two processes. Acidic and neutral conditions were good for NDEA degradation by sole UV irradiation. However, NDEA underwent rapid degradation under various pH conditions in the UV/O(3) process. Though the ozone introduction in the UV/O(3) process had little effect on NDEA degradation efficiency, it had significant effect on its degradation products and pathways. Methylamine, dimethylamine, ethylamine and diethylamine were observed as aliphatic amine products of NDEA degradation in both two processes. They were assumed to arise due to N-N bond fission under UV irradiation, or due to the reaction of NDEA and hydroxyl radicals in the UV/O(3) process.

  1. Bacterial degradation of recalcitrant PAHs: metabolic studies and application to pyrene degradation in a freshwater sediment

    Energy Technology Data Exchange (ETDEWEB)

    Jouanneau, Y.; Demaneche, S.; Meyer, Ch.; Willison, J.C. [CEA-Grenoble, UMR 5092 CNRS-CEA-UJF, 38 - Grenoble (France)

    2005-07-01

    oxygen diffusion into the sediment layer. In microcosms inoculated with strain 6PY1, the mineralization rate was even higher but slowly declined over time. Mineralization activity was accompanied by the release of water-soluble pyrene oxidation products, the most abundant of which was identified as 4,5-diphenanthroic acid. Among the pyrene-degrading isolates selected from the indigenous microflora, M. austroafricanum strains were the most abundant, although a Gram-negative Stenotrophomonas maltophilia strain was also isolated. Our studies thus demonstrate that plants or selected PAH-degrading bacteria enhance pollutant removal from contaminated sediment. (authors)

  2. Formation and degradation of valuable intermediate products during wet oxidation of municipal sludge.

    Science.gov (United States)

    Baroutian, Saeid; Gapes, Daniel J; Sarmah, Ajit K; Farid, Mohammed M; Young, Brent R

    2016-04-01

    The current study investigated the formation of organic acids and alcohols as major intermediate products of wet oxidation of municipal sludge. Municipal sludge was subjected to 60-min wet oxidation at temperatures ranging from 220 to 240°C, with 20bar oxygen partial pressure. Acetic acid was the main intermediate compound produced in this study, followed by propionic, n-butyric, iso-butyric and pentanoic acids and methanol. It was found that the process severity has a significant influence on the formation and degradation of these intermediate products.

  3. Photocatalytic degradation of tetracycline by Ti-MCM-41 prepared at room temperature and biotoxicity of degradation products

    Science.gov (United States)

    Zhou, Kefu; Xie, Xiao-Dan; Chang, Chang-Tang

    2017-09-01

    Ti-doped MCM-41 with different Si/Ti molar ratios was prepared at room temperature to degrade tetracycline antibiotics in aqueous solution. The Ti was doped into the skeleton structure of MCM-41. The photocatalytic activity of Ti-doped MCM-41 was investigated. The optimal catalyst had Si/Ti molar ratio of 25 and over 99% removal of oxytetracycline in 150 min, and the removal could maintain 98% after 5 reuses. Ions and soluble organic matters in natural water affected the degradation reaction when Ti-doped MCM-41 was used to treat simulated wastewater of chicken farms. The degradation products of oxytetracycline, tetracycline and chlortetracycline were detected by Escherichia coli DH5α and HPLC-MS/MS. No intermediate product with higher toxicity was detected.

  4. Synergistic collaboration of gut symbionts in Odontotermes formosanus for lignocellulosic degradation and bio-hydrogen production.

    Science.gov (United States)

    Mathew, Gincy Marina; Mathew, Dony Chacko; Lo, Shou-Chen; Alexios, Georgy Mathew; Yang, Jia-Cih; Sashikumar, Jagathala Mahalingam; Shaikh, Tanveer Mahamadali; Huang, Chieh-Chen

    2013-10-01

    In this work, gut microbes from the macrotermitine termite Odontotermes formosanus the cellulolytic Bacillus and fermentative Clostridium were studied in batch experiments using different carbon substrates to bio-mimic the termite gut for hydrogen production. Their fungus comb aging and the in vitro lignocellulosic degradation of the mango tree substrates by the synergistic interaction of Bacillus, Clostridium and Termitomyces were detected by Solid-state NMR. From the results, Bacillus species acted as a mutualist, by initiating an anaerobic environment for the growth of Clostridium, for bio-hydrogen production and the presence of Termitomyces enhanced the lignocellulosic degradation of substrates in vitro and in vivo. Thus, the synergistic collaboration of these three microbes can be used for termite-derived bio-fuel processing technology.

  5. Identification of major degradation products of 5-aminosalicylic acid formed in aqueous solutions and in pharmaceuticals

    DEFF Research Database (Denmark)

    Jensen, J.; Cornett, Claus; Olsen, C. E.

    1992-01-01

    The formation of four major degradation products of 5-aminosalicylic acid (5-ASA) in buffered solutions at pH 7.0 was demonstrated by gradient HPLC analysis. The isolation and structural elucidation of the resulting degradation products showed that the degradation of 5-ASA led to the formation of......-containing pharmaceuticals, which had not been stored as prescribed, but in diffuse daylight for up to 2 years....

  6. Photodegradation of sparfloxacin and isolation of its degradation products by preparative HPLC

    Directory of Open Access Journals (Sweden)

    H. R.N. SALGADO

    2009-01-01

    Full Text Available

    Sparfloxacin, a third generation fluoroquinolone derivative, is a potent antibacterial agent active against a wide range of Gram-positive and Gram-negative organisms including Streptococcus pneumoniae, Staphylococcus aureus, methicillin resistant S. aureus, Legionella spp., Mycoplasma spp., Chlamydia spp. and Mycobacterium spp. A drawback of fluoroquinolones is their photoreactivity. Sparfloxacin has been studied in terms of therapeutic activities. However, there are few published of analytical methods being applied to sparfloxacin. The aim in this study was to determine the photodegradation products of sparfloxacin, when submitted to UV light, and to characterize two of these products, designated SPAX-PDP1 and SPAX-PDP2. An accelerated study of stability in methanol solution was carried out by exposing a solution of sparfloxacin to UV light (peak wavelength 290 nm for 36 hours at room temperature. The products were analyzed by NMR spectrophotometry, IR spectrometry and mass spectrophotometry. The results suggest that the products isolated here could be used to estimate the degradation of sparfloxacin in a stability study. However, the low activity exhibited by UV-irradiated sparfloxacin is a source of concern that demands further investigation of the mechanism of its photodegradation mechanism. Keywords: Degradation products, fluoroquinolone, photodegradation, quality control, sparfloxacin, stability.

  7. 牛毛降解物-淀粉两性填充材料研究%Study on amphoteric fillers of cowhair degradation product and starch

    Institute of Scientific and Technical Information of China (English)

    张本民; 单志华; 陈治军

    2016-01-01

    The discard cowhair from tannery was preprocessed, dissolved respectively under the acidic and alkaline conditions.Two slight fragrance products, Fill HS-1 and Fill HS-2, were synthesized by the reaction of dissolved matters with corn starch.The solid contents of Fill HS-1 and FillHS-2 all are 37%.The viscosities are 350mPa · s and 400mPa · s.The average molecular weight of acid and alkali dissolved matters measured with SDS-PAGE electrophoresis are 3 000 ~ 5 000Da and 7 000 ~20 000Da.And the average molecular weight of Fill HS-1 and Fill HS-2 are all above 20 000Da.Isoelectric point(pI) of Fill HS-1 and Fill HS-2 are 5.2 and 5.7 respectively.Tanned by Fill HS-1 or Fill HS-2 the leathers' Ts all are 55℃, however,tanned by combining Fill HS-1 with Al salt the leather's Ts is 66.5℃ and the thickness of the leather increases 30%.Tanned by combining Fill HS-2 with Al salt the leather's Ts is 65 ℃ and the thickness of the leather increases 45 %.Compared with commodity filling agents, the leather softness increase by 20.5% and 16.7% when wet bule is filled with Fill HS-1 and HS-2 fillers.SEM figure shows the Fill HS-1 and Fill HS-2 could separate leather fiber bundles obviously, of which the former does more fine and even.%对皮革厂废弃牛毛进行预处理及酸或碱性条件下溶解后,分别与玉米淀粉进行反应,分别得到固含量为37%、黏度400mPa·s、有淡香味的产物Fill HS-1及Fill HS-2.十二烷基硫酸钠-聚丙烯酰胺凝胶(SDS-PAGE)电泳测定了降解物以及合成物Fill HS-1、Fill HS-2的相对分子质量.毛在酸或碱性条件下降解物的相对分子质量分别为3 000~5 000Da、7 000 ~ 20 000Da;Fill HS-1、Fill HS-2的相对分子质量均在22 000Da以上.试验测得Fill HS-1、Fill HS-2的等电点分别为5.2、5.7.应用结果显示:2种合成产物单独鞣革的Ts只有55℃.而Fill HS-1与铝盐结合鞣时,Ts为66.5℃,增厚30%;Fill HS-2结合鞣革的Ts为65℃,增厚45

  8. Optimization of fipronil degradation by heterogeneous photocatalysis: Identification of transformation products and toxicity assessment.

    Science.gov (United States)

    Gomes Júnior, Oswaldo; Borges Neto, Waldomiro; Machado, Antonio E H; Daniel, Daniela; Trovó, Alam G

    2017-03-01

    In this work it was studied the degradation of the insecticide fipronil (FIP) by heterogeneous photocatalysis induced by TiO2 P25. Using chemometric methods (Factorial Design and Response Surface Methodology), it was possible to evaluate the role of interaction between pH of the reaction medium, the reaction time and concentration of TiO2, optimizing the conditions for degradation using artificial radiation. Under the optimized conditions (79.4 mg L(-1) TiO2 and 66.3 min of reaction time for 1.1 mg L(-1) of FIP, at pH 5.6-5.8 (natural pH of the irradiated suspension)), 90.9% of FIP degradation was achieved at a degradation rate of 1.54 × 10(-2) m(2) kJ(-1) in terms of accumulated UVA radiation, corresponding to a pseudo-first order rate constant of 1.34 × 10(-2) min(-1) and a half-life of 51.7 min. Under the same conditions, these assays were extended to the use of solar radiation, when the degradation rate was 14% higher, with half-life of 45 min, suggesting that in both cases FIP degradation was successful. Four by-products of FIP photocatalytic degradation could be separated, identified, and their formation and consumption followed by UHPLC-Q-TOF. Although the same intermediates have been obtained using both irradiation sources, a faster degradation of the transformation products (TPs) was observed under solar irradiation due to its expressive photonic flux covering the UVA and UVB. It is noteworthy that both the untreated effluent and the identified compounds have low toxicity with respect to V. fischeri, suggesting that the heterogeneous photocatalysis may be a good alternative for treatment of wastewaters containing FIP and its TPs, mainly when solar radiation is the source of radiation, since under this condition the power consumption during the treatment can be significantly reduced. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Glucosinolate degradation products, isothiocyanates, nitriles, and thiocyanates, induce stomatal closure accompanied by peroxidase-mediated reactive oxygen species production in Arabidopsis thaliana.

    Science.gov (United States)

    Hossain, Mohammad Shakhawat; Ye, Wenxiu; Hossain, Mohammad Anowar; Okuma, Eiji; Uraji, Misugi; Nakamura, Yoshimasa; Mori, Izumi C; Murata, Yoshiyuki

    2013-01-01

    Isothiocyanates, nitriles, and thiocyanates are degradation products of glucosinolates in crucifer plants. In this study, we investigated the stomatal response to allyl isothiocyanate (AITC), 3-butenenitrile (3BN), and ethyl thiocyanate (ESCN) in Arabidopsis. AITC, 3BN, and ESCN induced stomatal closure in the wild type and the atrbohD atrbohF mutant. Stomatal closure was inhibited by catalase and salicylhydroxamic acid (SHAM). The degradation products induced extracellular reactive oxygen species (ROS) production in the rosette leaves, and intracellular ROS accumulation, NO production, and cytosolic free calcium concentration ([Ca(2+)]cyt) oscillations in guard cells, which were inhibited by SHAM. These results suggest that glucosinolate degradation products induce stomatal closure accompanied by extracellular ROS production mediated by SHAM-sensitive peroxidases, intracellular ROS accumulation, and [Ca(2+)]cyt oscillation in Arabidopsis.

  10. Thermal Degradation Studies of Polyurethane/POSS Nanohybrid Elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, J P; Pielichowski, K; TremblotDeLaCroix, P; Janowski, B; Todd, D; Liggat, J J

    2010-03-05

    Reported here is the synthesis of a series of Polyurethane/POSS nanohybrid elastomers, the characterization of their thermal stability and degradation behavior at elevated temperatures using a combination of Thermal Gravimetric Analysis (TGA) and Thermal Volatilization Analysis (TVA). A series of PU elastomers systems have been formulated incorporating varying levels of 1,2-propanediol-heptaisobutyl-POSS (PHIPOSS) as a chain extender unit, replacing butane diol. The bulk thermal stability of the nanohybrid systems has been characterized using TGA. Results indicate that covalent incorporation of POSS into the PU elastomer network increase the non-oxidative thermal stability of the systems. TVA analysis of the thermal degradation of the POSS/PU hybrid elastomers have demonstrated that the hybrid systems are indeed more thermally stable when compared to the unmodified PU matrix; evolving significantly reduced levels of volatile degradation products and exhibiting a {approx}30 C increase in onset degradation temperature. Furthermore, characterization of the distribution of degradation products from both unmodified and hybrid systems indicate that the inclusion of POSS in the PU network is directly influencing the degradation pathways of both the soft and hard block components of the elastomers: The POSS/PU hybrid systems show reduced levels of CO, CO2, water and increased levels of THF as products of thermal degradation.

  11. Effect of caffeine concentration on biomass production, caffeine degradation, and morphology of Aspergillus tamarii

    OpenAIRE

    Gutierrez-Sanchez, G.; Roussos, Sevastianos; Augur, Christopher

    2013-01-01

    The aim of the present study was to evaluate the effect of the initial caffeine concentration (1-8 g/L) on growth and caffeine consumption by Aspergillus tamarii as well as pellet morphology, in submerged fermentation. Caffeine was used as sole nitrogen source. At 1 g/L of initial caffeine concentration, caffeine degradation was not affected, resulting in a production of 8.7 g/L of biomass. The highest biomass production (12.4-14.8 g/L) was observed within a range of 2 to 4 g/L of initial caf...

  12. PRODUCTION AND RECOVERY OF POLY-Β-HYDROXYBUTYRATE FROM WHEY DEGRADATION BY AZOTOBACTER

    Directory of Open Access Journals (Sweden)

    A. Khanafari , A. Akhavan Sepahei, M. Mogharab

    2006-07-01

    Full Text Available Three strains of Azotobacter chroococcum were studied to produce poly-β hydroxybutyrate as a inclusion body by whey degradation. Optimum degradation whey results were obtained when using whey broth as a fermentation medium without extra salt, temperature at 35 °C and pH 7 (P<0.05. Lambda max for whey broth medium was determined probably about 400 nm. The effect of different nitrogenous rich compounds (NH4NO3, Bactopeptone, Casein, Yeast extract, Meat extract, Protease peptone and Tryptone on whey degradation showed that incorporation of nitrogenous compounds into the medium did not increase whey degradation by Azotobacter chroococcum 1723 (P<0.05. But poly-β hydroxyl-butyrate production was increased in presence Meat extract up to 75% of the cell dry weight after 48h. The addition of nitrogenous sourced (except ammonium nitrate had a positive effect on poly-β hydroxyl-butyrate production as it peaked in the presence of Meat extract and 4.43 g/L was accumulated in comparison to 0.5g at diazotrophically growing cells. Increasing the O2 values resulted by shaking at 122 rpm in decreased poly-β hydroxyl-butyrate yield form 4.43 to 0.04 g/L. The results show that this medium supports the growth of strain 1735 and also that this waste could be utilized as a carbon and nitrogen source. Production of poly-β hydroxyl-butyrate by using whey as a medium looks promising, since the use of inexpensive feed-stocks for poly-β hydroxyl-butyrate is essential if bioplastics are to become competitive products.

  13. The opposing effects of bacterial activity and gas production on anaerobic TCE degradation in soil columns.

    Science.gov (United States)

    Singhal, Naresh; Jaffé, Peter; Maier, Walter; Jho, Eun Hea

    2007-11-01

    This laboratory study explores the effect of growth substrate concentration on the anaerobic degradation of trichloroethylene (TCE) in sand packed columns. In all columns the growth substrate rapidly degraded to gas, that formed a separate phase. Biomass accumulated in the 0-4.8 cm section of the columns in proportion to the influent growth substrate concentration and biomass concentrations in the remaining sections of all columns were similar to the column receiving the lowest substrate concentration. Increases in growth substrate concentration up to 3030 mg-CODl(-1) promoted TCE degradation, but a further increase to 14300 mg-CODl(-1) reduced the amount of TCE completely dechlorinated but did not affect the production of chlorinated TCE intermediates. The mathematical model developed here satisfactorily described the enhancement in TCE dehalogenation for substrate concentration up to 3030 mg-CODl(-1); reproducing TCE dehalogenation for 14300 mg-CODl(-1) required that the moisture content used in simulation be lowered to 0.1. The study shows that volatilization of TCE can be significant and volatilization losses should be taken into account when anaerobic activity in in-situ bioremediation applications is stimulated via addition of growth substrates. An implication of the modeling simulations is that maintaining a lower, but uniform, substrate concentration over the contaminated region may lead to faster contaminant degradation.

  14. Hydrogen and Carbon Black Production from the Degradation of Methane by Thermal Plasma

    Directory of Open Access Journals (Sweden)

    Leila Cottet

    2014-05-01

    Full Text Available Methane gas (CH4 is the main inducer of the so called greenhouse gases effect. Recent scientific research aims to minimize the accumulation of this gas in the atmosphere and to develop processes capable of producing stable materials with added value. Thermal plasma technology is a promising alternative to these applications, since it allows obtaining H2 and solid carbon from CH4, without the parallel formation of byproducts such as CO2 and NOx. In this work, CH4 was degraded by thermal plasma in order to produce hydrogen (H2 and carbon black. The degradation efficiency of CH4, selectivity for H2 production as well as the characterization of carbon black were studied. The best results were obtained in the CH4 flow rate of 5 L min-1 the degradation percentage and the selectivity for H2 production reached 98.8 % and 48.4 %, respectively. At flow rates of less than 5 L min-1 the selectivity for H2 production increases and reaches 91.9 %. The carbon black has obtained amorphous with hydrophobic characteristics and can be marketed to be used in composite material, and can also be activated chemically and/or physically and used as adsorbent material.

  15. Why do forest products become less available? A pan-tropical comparison of drivers of forest-resource degradation

    NARCIS (Netherlands)

    Hermans, Kathleen; Gerstner, Katharina; Geijzendorffer, Ilse R.; Herold, Martin; Seppelt, Ralf; Wunder, Sven

    2016-01-01

    Forest products provide an important source of income and wellbeing for rural smallholder communities across the tropics. Although tropical forest products frequently become over-exploited, only few studies explicitly address the dynamics of degradation in response to socio-economic drivers. Our

  16. Simultaneous determination of 19 triazine pesticides and degradation products in processed cereal samples from Chinese total diet study by isotope dilution–high performance liquid chromatography–linear ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng [College of Veterinary Medicine, China Agricultural University, Beijing 100193 (China); China National Center for Food Safety Risk Assessment, Beijing 100021 (China); Yang, Xin, E-mail: beijing-yangxin@163.com [China National Center for Food Safety Risk Assessment, Beijing 100021 (China); Miao, Hong; Zhao, Yunfeng [China National Center for Food Safety Risk Assessment, Beijing 100021 (China); Key Lab of Food Safety Risk Assessment, Ministry of Health, Beijing 100021 (China); Liu, Wei [Shandong Province Environmental Monitoring Centre, Jinan 250013 (China); Wu, Yongning, E-mail: china_cdc@yahoo.cn [College of Veterinary Medicine, China Agricultural University, Beijing 100193 (China); China National Center for Food Safety Risk Assessment, Beijing 100021 (China); Key Lab of Food Safety Risk Assessment, Ministry of Health, Beijing 100021 (China)

    2013-06-05

    Graphical abstract: -- Highlights: •19 triazines were determined in cereal samples from Chinese TDS for the first time. •Isotope dilution technique and HPLC–LIT-MS{sup 3} method are both applied in this study. •CCαs and CCβs are much lower in this work than those of the previous publications. -- Abstract: A selective and sensitive isotope dilution–high performance liquid chromatography–linear ion trap mass spectrometry (Isotope Dilution–HPLC–LIT-MS{sup 3}) method was developed for the simultaneous determination of 19 triazine pesticides and their degradation products in processed cereal samples from Chinese total diet study (TDS). The method integrated the addition of isotope internal standards, liquid–liquid extraction (LLE), clean-up with MCX solid-phase extraction (SPE) cartridges and HPLC–LIT-MS{sup 3} analysis with selected reaction monitoring (SRM) mode. Matrix-matched calibration curves showed good linearity (R{sup 2} ≥ 0.9940) verified by applying the Mandel's fitting test (p > 0.087) performed at the 95% confidence level. Decision limits (CCαs) and detection capabilities (CCβs) of the 19 triazine pesticides and their degradation products fell in the ranges of 0.0020–0.4200 μg kg{sup −1} and 0.0024–0.4500 μg kg{sup −1}, respectively. Recoveries ranged from 70.1% to 112.8%, with the relative standard deviations (RSDs) ranging from 1.5% to 13.5%. Furthermore, the proposed method was applied to analyzing the proposed cereal samples from the fourth Chinese TDS. Eleven triazines were detected in six cereal samples with the concentrations ranging from 0.013 to 0.987 μg kg{sup −1}. This method can also be used for the further determination of the triazines in other food group composites, and ultimately served as a methodological foundation for assessing the triazines in the average Chinese diet in the general population.

  17. Environmental degradation of Air Products` Vinex, Airflex and Airvol polymers through composting

    Energy Technology Data Exchange (ETDEWEB)

    Larson, M.A.; O`Brien, N.M. [Air Products and Chemicals, Inc., Allentown, PA (United States)

    1995-12-31

    With the growing public concern for environmental awareness, it has become increasingly important to market products which are considered environmentally friendly, i.e., non-toxic, recyclable or compostable. This concern, in part, represents a need to reduce waste streams currently entering landfills. Most compost facilities now in operation deal mainly with grass, leaves, yard waste and wastewater treatment plant sludges or other specific industrial waste streams. However, there are a growing number of experimental compost operations that are attempting to integrate a larger variety of waste streams, including plastics, into large scale compost operations. This study marks the first time that a full scale composting study has been used at Air Products to evaluate and demonstrate the degradation of Vinex thermoplastic PVOH resins and Airflex and Airvol emulsion binders. Results here have served to differentiate the Vinex product line for research and development, product application and marketing.

  18. Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole on nanocrystalline titania films in alkaline media: Effect of applied electrical bias on degradation and transformation products.

    Science.gov (United States)

    Tantis, Iosif; Bousiakou, Leda; Frontistis, Zacharias; Mantzavinos, Dionissios; Konstantinou, Ioannis; Antonopoulou, Maria; Karikas, George-Albert; Lianos, Panagiotis

    2015-08-30

    Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole has been studied in the presence of nanocrystalline titania films supported on glass slides or transparent FTO electrodes in alkaline environment. Its photocatalytic degradation rate was assessed by its UV absorbance and by HPLC, while its transformation products were analyzed by HR-LC-MS. Based on UV absorbance, omeprazole can be photocatalytically degraded at an average rate of 6.7×10(-4)min(-1) under low intensity UVA irradiation of 1.5mWcm(-2) in the presence of a nanoparticulate titania film. This corresponds to degradation of 1.4mg of omeprazole per gram of the photocatalyst per liter of solution per hour. The photodegradation rate can be accelerated in a photoelectrochemical cell by applying a forward bias. In this case, the maximum rate reached under the present conditions was 11.6×10(-4)min(-1) by applying a forward bias of +0.6V vs. Ag/AgCl. Four major transformation products were successfully identified and their profiles were followed by HR-LC-MS. The major degradation path includes the scission of the sulfoxide bridge into the corresponding pyridine and benzimidazole ring derivates and this is accompanied by the release of sulfate anions in the reaction mixture.

  19. Forced degradation of fingolimod: effect of co-solvent and characterization of degradation products by UHPLC-Q-TOF-MS/MS and 1H NMR.

    Science.gov (United States)

    Patel, Prinesh N; Kalariya, Pradipbhai D; Gananadhamu, S; Srinivas, R

    2015-11-10

    Fingolimod (FGL), an immunomodulator drug for treating multiple sclerosis, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per International Conference on Harmonization specified conditions. The drug showed extensive degradation under base hydrolysis, however, it was stable under all other conditions. A total of three degradation products (DPs) were observed. The chromatographic separation of the drug and its degradation products was achieved on a Fortis C18 (100×2.1mm, 1.7μm) column with a mobile phase composed of 0.1% formic acid (Solvent A) and acetonitrile (Solvent B) in gradient mode. All the DPs were identified and characterized by liquid chromatography-quadrupole time of flight-mass spectrometry (LC-Q-TOF-MS) in combination with accurate mass measurements. The major DP was isolated and characterized by Nuclear Magnetic resonance spectroscopy. This is a typical case of degradation where acetonitrile used as co-solvent in stress studies, reacts with FGL in base hydrolytic conditions to produce acetylated DPs. Hence, it can be suggested that acetonitrile is not preferable as a co-solvent for stress degradation of FGL. The developed UHPLC method was validated as per ICH guidelines.

  20. Degradation products of 2,4,6-Trinitrotoluene by a microbial consortia

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, O.; Parker, C.; Bender, J. [Clark Atlanta Univ., Atlanta, GA (United States)] [and others

    1995-12-01

    Remediation of contaminated soils can be accomplished using microbial species. Of particular interest is the remediation of explosive contaminated soils. A microbial consortia has been developed which removes TNT by an unexplained mechanism. Our goal is to understand the degradation of TNT by this microbial mat. Constructed mats have been generated in our laboratory by enriching water with ensiled grass and adding specific microbial components for organic degradation. Microbial mats are natural mixed microbial communities dominated by cyanobacterias (blue-green algae). In this research, degradation products of TNT have been identified using GC/MS. Ninety-seven percent of TNT (1000 mg/L), was removed in < 1 day by floating mats placed over TNT-contaminated water in quiescent ponds. Metabolites of TNT, 2, 4-Dinitro-6 amminotoluene and 2-Nitro-4,6 diaminotoluene has been observed after 1 day of mat treatment. A mechanism is postulated for this degradation showing that two of the nitro groups of the TNT molecule are being reduced to amino groups systematically. Anoxic zones in the mat, containing sulfur-reducing bacteria, may account for the reduction of TNT. GC/MS shows significant decreases in metabolite concentrations in 4-7 days, indicating continued degradation of TNT. It has been found by toxicity assays that these metabolites appeared to be nontoxic and nonmutagenic. These results suggest that floating microbial mats may be useful for the decontamination of sites in the environment contaminated with TNT. Further studies using {sup 13}C TNT will focus on the fate of the carbon, to determine the intermediates products prior to transformations into hydrocarbons or utilization by the bacteria consortia.

  1. Study on enhanced degradation of atrazine by ozonation in the presence of hydroxylamine.

    Science.gov (United States)

    Yang, Jingxin; Li, Ji; Dong, Wenyi; Ma, Jun; Cao, Jie; Li, Tingting; Li, Jiayin; Gu, Jia; Liu, Pingxin

    2016-10-05

    Degradation of atrazine (ATZ) by ozonation in the presence of hydroxylamine (HA) was experimentally investigated in this study. The results showed approximately 80% of ATZ was degraded by ozonation in the presence of HA, while only 20% was degraded by ozonation alone. The obvious inhibition of the ATZ degradation by tert-butanol suggested the enhanced ATZ degradation by ozone/HA was primarily attributed to OH. The OH yield was determined to be 25.8%. Additionally, the optimum HA dosage for the ATZ degradation was 4μM, when the ozone dosage was 20μM. The effects of pH, bicarbonate and temperature on ATZ degradation by ozone/HA were investigated in details. Most importantly, the enhanced ATZ degradation by ozonation in the presence of HA was still observed in real water especially at acidic pHs. Furthermore, the potential mechanism of OH formation during the reaction of ozone with HA was proposed herein. Nine products were identified by UPLC/Q-TOF-MS system. The ATZ degradation involved dealkylation, dechlorination-hydroxylation and olefination. The evolutions of the concentrations of three available transformation products including deethylatrazine, deisopropylatrazine and deethyldeisopropylatrazine in ozone/HA were evaluated and compared with that in ozonation alone.

  2. Stability of barakol under hydrolytic stress conditions and its major degradation product.

    Science.gov (United States)

    Chantong, Boonrat; Wongtongtair, Supim; Nusuetrong, Punnee; Sotanaphun, Uthai; Chaichantipyuth, Chaiyo; Meksuriyen, Duangdeun

    2009-03-01

    The aim of the present study was to investigate the stability of barakol, an anxiolytic constituent extracted from leaves of Senna siamea (Lam.) Irwin & Barneby (syn. Cassia siamea Lam.), under the International Conference on Harmonisation suggested conditions using HPLC with photodiode array detection. Extensive degradation of barakol was found to occur under alkaline conditions through base-catalyzed hydrolysis. Mild degradation of barakol was observed under thermal and oxidative stress while it was stable under acidic conditions. The reaction rate constants (Kobs) of barakol degradation under alkaline conditions at pHs 12 and 13 were 3.0x10(-5) and 9.6x10(-3) min(-1), respectively. The activation energy according to the Arrhenius plot was calculated to be 26.9+/-3.3 kcal/mol at pH 13 and temperatures between 12 and 51 degrees C. The major degradation product of barakol under both alkaline and thermal stress conditions was characterized by LC-MS and NMR as cassiachromone.

  3. Forest degradation and livelihood: a case study of government forest ...

    African Journals Online (AJOL)

    Forest degradation and livelihood: a case study of government forest ... Journal Home > Vol 10, No 2 (2017) > ... This study examined the effect of forest degradation on livelihood returns in ... Algeria (5); Benin (2); Botswana (3); Burkina Faso (3); Cameroon (8); Congo, Republic (1); Côte d'Ivoire (4); Egypt, Arab Rep.

  4. Phosphorus, carbon- and nitrogen interactions in productive and degraded tropical pastures

    Science.gov (United States)

    Oberson, A.; Hegglin, D. D.; Nesper, M.; Rao, I.; Fonte, S.; Ramirez, B.; Velasquez, J.; Tamburini, F.; Bünemann, E. K.; Frossard, E.

    2011-12-01

    Pastures are the main land use in deforested areas of tropical South America. The highly weathered soils of these regions usually have low total and available phosphorus (P) contents. Low P availability can strongly limit plant and animal productivity and other soil ecosystem functions. Most introduced pastures of Brachiaria spp. are grass-alone (GA) while some are grass-legume (GL) pastures. The majority of the introduced pastures, particularly the grass-alone are at some state of degradation (GD). Pasture degradation induces severe loss of plant biomass production, with drastic ecological and economic implications. Although the importance of P deficiency in pasture degradation has been recognized, the knowledge generated on stoichiometry of carbon (C), nitrogen (N) and P along pathways of the nutrient cycles of pastures, with different botanical composition and productivity, has been very limited. We will present results of a case study realized during 2010 to 2011 in the forest margins agro-ecosystem of the department of Caquetá, Colombia. Our objectives were to determine: i) whether P availability is lower in degraded compared to productive pastures, and ii) whether the introduction of legumes in the pasture increases P availability through enhanced biological P cycling through plant growth, plant litter decomposition and the soil microbial biomass; and iii) whether pasture types (GA vs GL) and the state of pasture degradation affect the C:N:P ratios in nutrient pools of the soil-plant system. An on-farm study was conducted on nine farms in the department of Caquetá, Colombia. On every farm three different pasture types were studied: degraded grass alone pastures (GD), productive grass-alone pastures (GA) and productive grass-legume pastures (GL). Basic soil characteristics and indicators on soil P status, microbial P cycling, plant biomass production, plant litter deposition and nutrient concentrations in plant tissue were determined. Analysis of P, C and N

  5. Teratogenicity of Ochratoxin A and the Degradation Product, Ochratoxin α, in the Zebrafish (Danio rerio) Embryo Model of Vertebrate Development.

    Science.gov (United States)

    Haq, Mehreen; Gonzalez, Nelson; Mintz, Keenan; Jaja-Chimedza, Asha; De Jesus, Christopher Lawrence; Lydon, Christina; Welch, Aaron; Berry, John P

    2016-02-05

    Ochratoxins, and particularly ochratoxin A (OTA), are toxic fungal-derived contaminants of food and other agricultural products. Growing evidence supports the degradation of OTA by chemical, enzymatic and/or microbial means as a potential approach to remove this mycotoxin from food products. In particular, hydrolysis of OTA to ochratoxin α (OTα) and phenylalanine is the presumptive product of degradation in most cases. In the current study, we employed the zebrafish (Danio rerio) embryo, as a model of vertebrate development to evaluate, the teratogenicity of OTA and OTα. These studies show that OTA is potently active in the zebrafish embryo toxicity assay (ZETA), and that toxicity is both concentration- and time-dependent with discernible and quantifiable developmental toxicity observed at nanomolar concentrations. On the other hand, OTα had no significant effect on embryo development at all concentrations tested supporting a decreased toxicity of this degradation product. Taken together, these results suggest that ZETA is a useful, and highly sensitive, tool for evaluating OTA toxicity, as well as its degradation products, toward development of effective detoxification strategies. Specifically, the results obtained with ZETA, in the present study, further demonstrate the toxicity of OTA, and support its degradation via hydrolysis to OTα as an effective means of detoxification.

  6. Teratogenicity of Ochratoxin A and the Degradation Product, Ochratoxin α, in the Zebrafish (Danio rerio) Embryo Model of Vertebrate Development

    Science.gov (United States)

    Haq, Mehreen; Gonzalez, Nelson; Mintz, Keenan; Jaja-Chimedza, Asha; De Jesus, Christopher Lawrence; Lydon, Christina; Welch, Aaron Z.; Berry, John P.

    2016-01-01

    Ochratoxins, and particularly ochratoxin A (OTA), are toxic fungal-derived contaminants of food and other agricultural products. Growing evidence supports the degradation of OTA by chemical, enzymatic and/or microbial means as a potential approach to remove this mycotoxin from food products. In particular, hydrolysis of OTA to ochratoxin α (OTα) and phenylalanine is the presumptive product of degradation in most cases. In the current study, we employed the zebrafish (Danio rerio) embryo, as a model of vertebrate development to evaluate, the teratogenicity of OTA and OTα. These studies show that OTA is potently active in the zebrafish embryo toxicity assay (ZETA), and that toxicity is both concentration- and time-dependent with discernible and quantifiable developmental toxicity observed at nanomolar concentrations. On the other hand, OTα had no significant effect on embryo development at all concentrations tested supporting a decreased toxicity of this degradation product. Taken together, these results suggest that ZETA is a useful, and highly sensitive, tool for evaluating OTA toxicity, as well as its degradation products, toward development of effective detoxification strategies. Specifically, the results obtained with ZETA, in the present study, further demonstrate the toxicity of OTA, and support its degradation via hydrolysis to OTα as an effective means of detoxification. PMID:26861395

  7. Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole on nanocrystalline titania films in alkaline media: Effect of applied electrical bias on degradation and transformation products

    Energy Technology Data Exchange (ETDEWEB)

    Tantis, Iosif [Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras (Greece); Bousiakou, Leda [Department of Physics and Astronomy, King Saud University, Riyadh (Saudi Arabia); Department of Automation Engineering, Technological Educational Institute of Pireaus, GR-12244 Athens (Greece); Frontistis, Zacharias; Mantzavinos, Dionissios [Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras (Greece); Konstantinou, Ioannis; Antonopoulou, Maria [Department of Environmental and Natural Resources Management, University of Patras, GR-30100 Agrinio (Greece); Karikas, George-Albert [Department of Medical Laboratories Technology, Technological Educational Institute of Athens, 12210 Athens (Greece); Lianos, Panagiotis, E-mail: lianos@upatras.gr [Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras (Greece); FORTH/ICE-HT, P.O. Box 1414, GR-26504 Patras (Greece)

    2015-08-30

    Highlights: • Photocatalytic and photoelectrocatalytic degradation of the proton pump omeprazole. • Improvement of photocatalysis rate by applying a moderate forward bias. • Highlighting of the advantages of photoelectrocatalysis in a straightforward manner. • HPLC and HR-LC–MS analysis of transformation products. - Abstract: Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole has been studied in the presence of nanocrystalline titania films supported on glass slides or transparent FTO electrodes in alkaline environment. Its photocatalytic degradation rate was assessed by its UV absorbance and by HPLC, while its transformation products were analyzed by HR-LC–MS. Based on UV absorbance, omeprazole can be photocatalytically degraded at an average rate of 6.7 × 10{sup −4} min{sup −1} under low intensity UVA irradiation of 1.5 mW cm{sup −2} in the presence of a nanoparticulate titania film. This corresponds to degradation of 1.4 mg of omeprazole per gram of the photocatalyst per liter of solution per hour. The photodegradation rate can be accelerated in a photoelectrochemical cell by applying a forward bias. In this case, the maximum rate reached under the present conditions was 11.6 × 10{sup −4} min{sup −1} by applying a forward bias of +0.6 V vs. Ag/AgCl. Four major transformation products were successfully identified and their profiles were followed by HR-LC–MS. The major degradation path includes the scission of the sulfoxide bridge into the corresponding pyridine and benzimidazole ring derivates and this is accompanied by the release of sulfate anions in the reaction mixture.

  8. Effect of Boric Acid on Volatile Products of Thermooxidative Degradation of Epoxy Polymers

    Science.gov (United States)

    Nazarenko, O. B.; Bukhareva, P. B.; Melnikova, T. V.; Visakh, P. M.

    2016-01-01

    The polymeric materials are characterized by high flammability. The use of flame retardants in order to reduce the flammability of polymers can lead to the formation of toxic gaseous products under fire conditions. In this work we studied the effect of boric acid on the volatile products of thermooxidative degradation of epoxy polymers. The comparative investigations were carried out on the samples of the unfilled epoxy resin and epoxy resin filled with a boric acid at percentage 10 wt. %. The analysis of the volatile decomposition products and thermal stability of the samples under heating in an oxidizing medium was performed using a thermal mass-spectrometric analysis. It is found that the incorporation of boric acid into the polymer matrix increases the thermal stability of epoxy composites and leads to a reduction in the 2-2.7 times of toxic gaseous products

  9. Photochemical degradation of ciprofloxacin in UV and UV/H₂O₂ process: kinetics, parameters, and products.

    Science.gov (United States)

    Guo, Hong-Guang; Gao, Nai-Yun; Chu, Wen-Hai; Li, Lei; Zhang, Yong-Ji; Gu, Jin-Shan; Gu, Yu-Liang

    2013-05-01

    Photochemical degradation of fluoroquinolone ciprofloxacin (CIP) in water by UV and UV/H₂O₂ were investigated. The degradation rate of CIP was affected by pH, H₂O₂ dosage, as well as the presence of other inorganic components. The optimized pH value and H₂O₂ concentration were 7.0 and 5 mM. Carbonate and nitrate both impeded CIP degradation. According to liquid chromatography-tandem mass spectrometry analysis, four and 16 products were identified in UV and UV/H₂O₂ system, respectively. Proposed degradation pathways suggest that reactions including the piperazinyl substituent, quinolone moiety, and cyclopropyl group lead to the photochemical degradation of CIP. Toxicity of products assessed by Vibrio qinghaiensis demonstrated that UV/H₂O₂ process was more capable on controlling the toxicity of intermediates in CIP degradation than UV process.

  10. Study of alteration and degradation products of a Roman marble sarcophagus located in the medieval cloister of the old st Cosimato’s Convent, now the new "Regina Margherita Hospital” (Rome

    Directory of Open Access Journals (Sweden)

    Gino Mirocle Crisci

    2009-03-01

    Full Text Available Optical and SEM-EDS microscopy, FT-IR and mFT-IR spectroscopy investigations have been applied to the study of alteration and degradation products of a Roman sarcophagus located in the medieval cloister of St Cosimato’s Convent, now the new “Regina Margherita Hospital” (Rome before restoration work. This scientific analysis was performed in order to compare it with a diagnosis report based on the restorer’s expertise. The sarcophagus is small and consists of a single block of fine-grained marble covered by a thick pink patina. The results obtained from this diagnostic investigation, allow us to draw important conclusions about the state of conservation of this archaeological artefact. The main components found in the samples analyzed are: black crust, calcium oxalate, organic matter due to recent conservation treatment, calcite, iron-oxides and coloured earths. In particular, the combined used of petrographical and mFT-IR analysis provided useful insights into the polishing and consolidation processes of archaeological artefacts.

  11. Sorption and degradation of pharmaceuticals and personal care products (PPCPs) in soils.

    Science.gov (United States)

    Yu, Yong; Liu, Yin; Wu, Laosheng

    2013-06-01

    Pharmaceuticals and personal care products (PPCPs) are one class of the most urgent emerging contaminants, which have drawn much public and scientific concern due to widespread contamination in aquatic environment. Most studies on the environmental fate and behavior of PPCPs have focused on nonsteroidal anti-inflammatory drugs. Some other compounds with high concentrations were less mentioned. In this study, sorption and degradation of five selected PPCPs, including bisphenol A (BPA), carbamazepine (CBZ), gemfibrozil (GFB), octylphenol (OP), and triclosan (TCS) have been investigated using three different soils. Sorption isotherms of all tested PPCPs in soils were well described by Freundlich equation. TCS and OP showed moderate to strong sorption, while the sorption of GFB and CBZ in soils was negligible. Degradation of PPCPs in three soils was generally fitted first-order exponential decay model, with half-lives (t 1/2) varying from 9.8 to 39.1 days. Sterilization could prolong the t 1/2 of PPCPs in soil, indicating that microbial activity played an important role in the degradation of these chemicals in soils. Degradation of PPCPs in soils was also influenced by the soil organic carbon (f oc) contents. Results from our data show that sorption to the soils varied among the different PPCPs, and their sorption affinity on soil followed the order of TCS > OP > BPA > GFB > CBZ. The degradation of the selected PPCPs in soil was influenced by the microbial activity and soil type. The poor sorption and relative persistence of CBZ suggest that it may pose a high leaching risk for groundwater contamination when recycled for irrigation.

  12. Production of rhamnolipids and diesel oil degradation by bacteria isolated from soil contaminated by petroleum.

    Science.gov (United States)

    Leite, Giuseppe G F; Figueirôa, Juciane V; Almeida, Thiago C M; Valões, Jaqueline L; Marques, Walber F; Duarte, Maria D D C; Gorlach-Lira, Krystyna

    2016-03-01

    Biosurfactants are microbial secondary metabolites. The most studied are rhamnolipids, which decrease the surface tension and have emulsifying capacity. In this study, the production of biosurfactants, with emphasis on rhamnolipids, and diesel oil degradation by 18 strains of bacteria isolated from waste landfill soil contaminated by petroleum was analyzed. Among the studied bacteria, gram-positive endospore forming rods (39%), gram positive rods without endospores (17%), and gram-negative rods (44%) were found. The following methods were used to test for biosurfactant production: oil spreading, emulsification, and hemolytic activity. All strains showed the ability to disperse the diesel oil, while 77% and 44% of the strains showed hemolysis and emulsification of diesel oil, respectively. Rhamnolipids production was observed in four strains that were classified on the basis of the 16S rRNA sequences as Pseudomonas aeruginosa. Only those strains showed the rhlAB gene involved in rhamnolipids synthesis, and antibacterial activity against Escherichia coli, P. aeruginosa, Staphylococcus aureus, Bacillus cereus, Erwinia carotovora, and Ralstonia solanacearum. The highest production of rhamnolipids was 565.7 mg/L observed in mineral medium containing olive oil (pH 8). With regard to the capacity to degrade diesel oil, it was observed that 7 strains were positive in reduction of the dye 2,6-dichlorophenolindophenol (2,6-DCPIP) while 16 had the gene alkane mono-oxygenase (alkB), and the producers of rhamnolipids were positive in both tests. Several bacterial strains have shown high potential to be explored further for bioremediation purposes due to their simultaneous ability to emulsify, disperse, and degrade diesel oil. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:262-270, 2016.

  13. Forced degradation, LC-UV, MS(n) and LC-MS-TOF studies on azilsartan: Identification of a known and three new degradation impurities.

    Science.gov (United States)

    Kaushik, Dhiraj; Kaur, Jasmeen; Paul Kaur, Vaneet; Saini, Balraj; Bansal, Yogita; Bansal, Gulshan

    2016-02-20

    In the present study, Azilsartan (AZL) was subjected to ICH recommended forced degradation conditions of hydrolysis, oxidation, dry heat and photolysis. The drug degraded to four degradation products (I-IV) under acidic, alkaline and water hydrolysis and photolysis. All the four degradation products were resolved in a single run on a C-18 column (250mm×4.6mm; 5μ) with isocratic elution using mobile phase composed of ammonium formate (20mM, pH 3.0), methanol and acetonitrile (40:5:40% v/v), at a flow rate of 0.8mlmin(-1) at ambient temperature. The products were characterized through +ESI-MS(n) spectra of AZL and LC-MS-TOF studies as 2-ethoxy-3H-benzo-imidazole-4-carboxylic acid (I), 2-hydroxy-3-[2'-(5-oxo-4,5-dihydro-[1,2,4]oxadiazol-4-ylmethyl]-3H-benzoimidazole-4-carboxylic acid (II, deethylated AZL), 3-[2'-(1H-diazirin-3-yl)-biphenyl]-4-ylmethyl]-2-ethoxy-3H-benzoimidazole-4-carboxylic acid (III), and 3-[4'-(2-ethoxy-benzo-imidazol-1-ylmethyl)-biphenyl-2-yl]-4H-[1,2,4]oxadiazol-5-one (IV, decarboxylated AZL). Product I was found to be a known process related impurity whereas the products II-IV were identified as new degradation impurities. The most probable mechanisms for formation of these degradation products were proposed.

  14. In vitro study on the degradation of lithium-doped hydroxyapatite for bone tissue engineering scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yaping; Yang, Xu; Gu, Zhipeng; Qin, Huanhuan [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Li, Li [Department of Oncology, The 452 Hospital of Chinese PLA, Chengdu, Sichuan Province 610021 (China); Liu, Jingwang [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Yu, Xixun, E-mail: yuxixun@163.com [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2016-09-01

    Li-doped hydroxyapatite (LiHA) which is prepared through introducing low dose of Li into hydroxyapatite (HA) has been increasingly studied as a bone tissue-engineered scaffold. The degradation properties play a crucial role in the success of long-term implantation of a bone tissue-engineered construct. Herein, the in vitro degradation behaviors of LiHA scaffolds via two approaches were investigated in this study: solution-mediated degradation and osteoblast-mediated degradation. In solution-mediated degradation, after being immersed in simulated body fluid (SBF) for some time, some characteristics of these scaffolds (such as release of ionized lithium and phosphate, pH change, mechanical properties, cytocompatibility and SEM surface characterization) were systematically tested. A similar procedure was also employed to research the degradation behaviors of LiHA scaffolds in osteoblast-mediated degradation. The results suggested that the degradation in SBF and degradation in culture medium with cell existed distinguishing mechanisms. LiHA scaffolds were degraded via a hydrolytic mechanism when they were soaked in SBF. Upon degradation, an apatite precipitation (layer) was formed on the surfaces of scaffolds. While a biological mechanism was presented for the degradation of scaffolds in cell-mediated degradation. Compared with pure HA, LiHA scaffolds had a better effect on the growth of osteoblast cells, meanwhile, the release amount of PO{sub 4}{sup 3−} in a degradation medium indicated that osteoblasts could accelerate the degradation of LiHA due to the more physiological activities of osteoblast. According to the results from compressive strength test, doping Li into HA could enhance the strength of HA. Moreover, the results from MTT assay and SEM observation showed that the degradation products of LiHA scaffolds were beneficial to the proliferation of osteoblasts. The results of this research can provide the theoretical basis for the clinical application of Li

  15. Detection of the spectroscopic signatures of explosives and their degradation products

    Science.gov (United States)

    Florian, Vivian; Cabanzo, Andrea; Baez, Bibiana; Correa, Sandra; Irrazabal, Maik; Briano, Julio G.; Castro, Miguel E.; Hernandez-Rivera, Samuel P.

    2005-06-01

    Detection and removal of antipersonnel and antitank landmines is a great challenge and a worldwide enviromental and humanitarian problem. Sensors tuned on the spectroscopic signature of the chemicals released from mines are a potential solution. Enviromental factors (temperature, relative humidity, rainfall precipitation, wind, sun irradiation, pressure, etc.) as well as soil characteristics (water content, compaction, porosity, chemical composition, particle size distribution, topography, vegetation, etc), have a direct impact on the fate and transport of the chemicals released from landmines. Chemicals such as TNT, DNT and their degradation products, are semi-volatile, and somewhat soluble in water. Also, they may adsorb strongly to soil particles, and are susceptible to degradation by microorganisms, light, or chemical agents. Here we show an experimental procedure to quantify the effect of the above variables on the spectroscopic signature. A number of soil tanks under controlled conditions are used to study the effect of temperature, water content, relative humidity and light radiation.

  16. Studies on hydrocarbon degradation by the bacterial isolate ...

    African Journals Online (AJOL)

    Studies on hydrocarbon degradation by the bacterial isolate ... Journal Home > Vol 4, No 3 (2015) > ... The degradation of 2 % heavy crude oil and other PAHs from the isolate PM-1 was assessed ... Algeria (5); Benin (2); Botswana (3); Burkina Faso (3); Cameroon (8); Congo, Republic (1); Côte d'Ivoire (4); Egypt, Arab Rep.

  17. Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.

    Science.gov (United States)

    McDonald, Jacob D; Kracko, Dean; Doyle-Eisele, Melanie; Garner, C Edwin; Wegerski, Chris; Senft, Al; Knipping, Eladio; Shaw, Stephanie; Rohr, Annette

    2014-09-16

    Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p < 0.05) total cells, neutrophils, and lymphocytes compared to control mice and caused inflammatory cytokine expression (statistical increase at p < 0.05). MEA and CO2-degraded MEA were the only atmospheres to show statistical (p < 0.05) increase in oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals.

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

    Science.gov (United States)

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

    2016-08-01

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

  19. Aqueous photodegradation of 4-tert-butylphenol: By-products, degradation pathway and theoretical calculation assessment

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yanlin [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Shi, Jin; Chen, Hongche [Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433 (China); Zhao, Jianfu [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Dong, Wenbo, E-mail: wbdong@fudan.edu.cn [Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433 (China)

    2016-10-01

    4-tert-butylphenol (4-t-BP), an endocrine disrupting chemical, is widely distributed in natural bodies of water but is difficult to biodegrade. In this study, we focused on the transformation of 4-t-BP in photo-initiated degradation processes. The steady-state photolysis and laser flash photolysis (LFP) experiments were conducted in order to elucidate its degradation mechanism. Identification of products was performed using the GC–MS, LC-MS and theoretical calculation techniques. The oxidation pathway of 4-t-BP by hydroxyl radical (HO·) was also studied and H{sub 2}O{sub 2} was added to produce HO·. 4-tert-butylcatechol and 4-tert-butylphenol dimer were produced in 4-t-BP direct photolysis. 4-tert-butylcatechol and hydroquinone were produced by the oxidation of HO·. But the formation mechanism of 4-tert-butylcatechol in the two processes was different. The benzene ring was fractured in 4-t-BP oxidation process and 29% of TOC was degraded after 16 h irradiation. - Highlights: • Photodegradation of 4-t-BP, an endocrine disrupting chemical, has been investigated. • 3 stable byproducts were identified from photolysis and oxidation processes. • 5 transient by-products were concluded from LFP experiments. • The theoretical calculation was performed to confirm the byproducts. • 4-t-BP was degraded with increasing efficiency: 254 nm < H{sub 2}O{sub 2}/313 nm < H{sub 2}O{sub 2}/254 nm.

  20. Oxidative degradation of alternative gasoline oxygenates in aqueous solution by ultrasonic irradiation: Mechanistic study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Duk Kyung, E-mail: dkim@aum.edu [Department of Physical Science, Auburn University Montgomery, Montgomery, AL 36117 (United States); O' Shea, Kevin E., E-mail: osheak@fiu.edu [Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199 (United States); Cooper, William J. [Department of Civil and Environmental Engineering, Urban Water Research Center, University of California Irvine, Irvine, CA 92697-2175 (United States)

    2012-07-15

    Widespread pollution has been associated with gasoline oxygenates of branched ethers methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl ether (TAME) which enter groundwater. The contaminated plume develops rapidly and treatment for the removal/destruction of these ethers is difficult when using conventional methods. Degradation of MTBE, with biological methods and advanced oxidation processes, are rather well known; however, fewer studies have been reported for degradation of alternative oxygenates. Degradation of alternative gasoline oxygenates (DIPE, ETBE, and TAME) by ultrasonic irradiation in aqueous oxygen saturation was investigated to elucidate degradation pathways. Detailed degradation mechanisms are proposed for each gasoline oxygenate. The common major degradation pathways are proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals generated during ultrasound cavitation and low temperature pyrolytic degradation of ETBE and TAME. Even some of the products from {beta}-H abstraction overlap with those from high temperature pyrolysis, the effect of {beta}-H abstraction was not shown clearly from product study because of possible 1,5 H-transfer inside cavitating bubbles. Formation of hydrogen peroxide and organic peroxides was also determined during sonolysis. These data provide a better understanding of the degradation pathways of gasoline oxygenates by sonolysis in aqueous solutions. The approach may also serve as a model for others interested in the details of sonolysis. - Highlights: Black-Right-Pointing-Pointer Gasoline oxygenates (ETBE, TAME, DIPE) were completely degraded after 6 hours under ultrasonic irradiation in O{sub 2} saturation. Black-Right-Pointing-Pointer The major degradation pathways were proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals and low temperature pyrolytic degradation. Black-Right-Pointing-Pointer The effect of {beta

  1. Forced degradation studies of ivabradine and in silico toxicology predictions for its new designated impurities

    Directory of Open Access Journals (Sweden)

    Piotr ePikul

    2016-05-01

    Full Text Available All activities aim to eliminate genotoxic impurities or/and protect the medicinal compounds against degradation. There is a need to monitor impurities from all classification groups, so that ivabradine forced degradation studies were performed. Ivabradine proved to be a quite durable active substance, but still new and not known particularly. Increasing temperature, acid, base, oxidation reagent and light cause its degradation. Thirteen degradation products were determined with the usage of HPLC equipped with Q-TOF-MS detector. Six of them, which the most probable structures managed to establish, were selected to ADME/Tox calculations for prediction studies of their pharmacological and toxicological properties. Target prediction algorithm was applied on the basis of Hyperpolarization-activated cyclic nucleotide-gated cation channels as well as more general parameters like logP and aqueous solubility. Ames test and five cytochromes activities were calculated for toxicity assessment of selected degradation products. Pharmacological activity of photodegradation product (UV4 that is known as active metabolite was qualified and identified. Two other degradation compounds (Ox1 and N1 which were formed during degradation process were found to be pharmacologically active with high probability.

  2. Toxicity of tetracyclines and tetracycline degradation products to environmentally relevant bacteria, including selected tetracycline-resistant bacteria

    DEFF Research Database (Denmark)

    Halling-Sørensen, B.; Sengeløv, G.; Tjørnelund, J.

    2002-01-01

    Tetracyclines used in veterinary therapy invariably will find their way as parent compound and degradation products to the agricultural field. Major degradation products formed due to the limited stability of parent tetracyclines (tetracycline, chlortetracycline, and oxytetracycline) in aqueous s...

  3. Production of cellulose and hemicellulose-degrading enzymes by filamentous fungi cultivated on wet-oxidised wheat straw

    DEFF Research Database (Denmark)

    Thygesen, A.; Thomsen, A.B.; Schmidt, A.S.

    2003-01-01

    The production of cellulose and hemicellulose-degrading enzymes by cultivation of Aspergillus niger ATCC 9029, Botrytis cinerea ATCC 28466, Penicillium brasilianum IBT 20888, Schizophyllum commune ATCC 38548, and Trichoderma reesei Rut-C30 was studied. Wet-oxidised wheat straw suspension suppleme......The production of cellulose and hemicellulose-degrading enzymes by cultivation of Aspergillus niger ATCC 9029, Botrytis cinerea ATCC 28466, Penicillium brasilianum IBT 20888, Schizophyllum commune ATCC 38548, and Trichoderma reesei Rut-C30 was studied. Wet-oxidised wheat straw suspension...

  4. Large-scale bioreactor production of the herbicide-degrading Aminobacter sp. strain MSH1

    DEFF Research Database (Denmark)

    Schultz-Jensen, Nadja; Knudsen, Berith Elkær; Frkova, Zuzana;

    2014-01-01

    The Aminobacter sp. strain MSH1 has potential for pesticide bioremediation because it degrades the herbicide metabolite 2,6-dichlorobenzamide (BAM). Production of the BAM-degrading bacterium using aerobic bioreactor fermentation was investigated. A mineral salt medium limited for carbon...

  5. Photocatalytic degradation of methyl blue by silver ion-doped titania: Identification of degradation products by GC-MS and IC analysis.

    Science.gov (United States)

    Sahoo, Chittaranjan; Gupta, Ashok K

    2015-01-01

    An anionic triphenyl methane dye, methyl blue ((disodium;4-[4-[[4-(4-sulfonatoanilino)phenyl]-[4-(4-sulfonatophenyl)azaniumylidenecyclohexa-2,5-dien-1-ylidene]methyl]anilino]benzene sulfonate) was degraded photocatalytically with undoped micro-TiO2- and Ag(+)-doped micro TiO2 in a slurry-type batch reactor under UV irradiation and the efficiency was compared with that obtained using nano-TiO2- and Ag(+)-doped nano-TiO2. The influence of different parameters, i.e., photocatalyst loading, dye concentration, initial pH, temperature, depth of solution, interfering ions and electron acceptors on the dye degradation was investigated. The decolorization and mineralization efficiency was better for Ag(+)-doped micro-TiO2 than undoped micro-TiO2. Nano-TiO2 was more efficient than micro-TiO2, while Ag(+)-doped nano-TiO2 was the most efficient of all. Cost analysis showed degradation using micro-TiO2- and Ag(+)-doped micro-TiO2 are much cheaper than that using nano-TiO2 and Ag(+)-doped nano-TiO2. Therefore Ag(+)-doped micro-TiO2 was used for the detailed study. The degradation products formed were identified using GC-MS analysis after photocatalytic degradation for 180 min with Ag(+) -doped micro TiO2. Ion chromatography analysis was carried out for anions to identify the end products of degradation.

  6. HPLC analysis, isolation and identification of a new degradation product in carvedilol tablets.

    Science.gov (United States)

    Galanopoulou, Olga; Rozou, Stavroula; Antoniadou-Vyza, Ekaterini

    2008-09-10

    Carvedilol (CV) is an antagonist of alpha1 and beta1,beta2 membrane adrenoceptors and also a modulator of cardiac electrophysiological properties. It is widely prescribed for the treatment of cardiovascular diseases. During stability testing of CV solid dosage forms an unknown degradation product referred as UP, exceeded the identification thresholds of ICH Q3B guidelines. The HPLC analysis of the detected unknown product was performed by a newly, developed, specific and validated method, also suitable for the quantitative determination of the known CV impurities (imp B, C, E and F) and the other degradation products. The separation was achieved with an X-terra C18 column, using acetonitrile-phosphate buffer pH 2.5 as mobile phase. The isolation of UP was carried out by semi-preparative chromatography method, followed by deep freezing of the collected fractions until the organic and the aqueous phases were separated. Chromatographic behaviour of CV and UP was compared, in mobile phases of different pH and gave valuable information concerning the dissimilarities of their ionization. UP was further studied by MS and 1H NMR spectrometry, revealing structural similarities with the parent molecule. Finally, the unknown peak of degradation product was attributed to a new compound generated from the interaction of CV molecule and polyvinyl pyrrolidone (PVP) in the presence of water molecules. Moisture and temperature was proved to affect the formation of UP and its concentration in CV tablets. Appropriate modifications of the packaging of CV tablets can be made in order to reduce UP concentration down to the accepted levels, during the tablets' shelf life.

  7. Ruminal degradation kinetics of protein foods by in vitro gas production technique

    Directory of Open Access Journals (Sweden)

    Ivone Yurika Mizubuti

    2014-02-01

    Full Text Available Chemical analysis of carbohydrates and nitrogen fractions, as well as, determination their carbohydrates digestion rates in soyben meal (SM, crambe meal (CM, radish meal (RM, wet brewery residue (WBR and dehydrated silkworm chrysalis (SCD were accomplished. The kinetics parameters of non-fibrous carbohydrates (NFC and B2 fraction were estimated using cumulative gas production technique. Among the foods studied there was considerable variation in chemical composition. The crambe meal was the only food that did not present synchronism between carbohydrate and nitrogen fractions. In this food there was predominance of A+B1 carbohydrates fractions and B1+B2 nitrogen compounds fraction, and for the other predominated B2 carbohydrate fraction and B1+ B2 nitrogen compounds fraction. There were differences among the digestive kinetic parameters for all foods. The greater participation in gas production due to non-fibrous carbohydrates was found in the crambe meal and oilseed radish meal. The fermentation of fibrous carbohydrates provided higher gas volume in the wet brewery residue and in the soybean meal, however, the soybean meal was food with higher total gas volume. Non fibrous carbohydrates degradation rates of wet brewery residue and dehydrated silkworm chrysalis were far below the limits of degradation of this fraction. Due to the parameters obtained by the cumulative gas production, the soybean meal was the best food, however, all others have potential for use in animal nutrition. The cumulative gas production technique allows the estimative of degradation rates and provides further information about the ruminal fermentation kinetics of foods.

  8. Fungal degradation of coal as a pretreatment for methane production

    Science.gov (United States)

    Haider, Rizwan; Ghauri, Muhammad A.; SanFilipo, John R.; Jones, Elizabeth J.; Orem, William H.; Tatu, Calin A.; Akhtar, Kalsoom; Akhtar, Nasrin

    2013-01-01

    Coal conversion technologies can help in taking advantage of huge low rank coal reserves by converting those into alternative fuels like methane. In this regard, fungal degradation of coal can serve as a pretreatment step in order to make coal a suitable substrate for biological beneficiation. A fungal isolate MW1, identified as Penicillium chrysogenum on the basis of fungal ITS sequences, was isolated from a core sample of coal, taken from a well drilled by the US. Geological Survey in Montana, USA. The low rank coal samples, from major coal fields of Pakistan, were treated with MW1 for 7 days in the presence of 0.1% ammonium sulfate as nitrogen source and 0.1% glucose as a supplemental carbon source. Liquid extracts were analyzed through Excitation–Emission Matrix Spectroscopy (EEMS) to obtain qualitative estimates of solubilized coal; these analyses indicated the release of complex organic functionalities. In addition, GC–MS analysis of these extracts confirmed the presence of single ring aromatics, polyaromatic hydrocarbons (PAHs), aromatic nitrogen compounds and aliphatics. Subsequently, the released organics were subjected to a bioassay for the generation of methane which conferred the potential application of fungal degradation as pretreatment. Additionally, fungal-mediated degradation was also prospected for extracting some other chemical entities like humic acids from brown coals with high huminite content especially from Thar, the largest lignite reserve of Pakistan.

  9. Identification of Degradation Products of Lincomycin and Iopromide by Electron Beam Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Yongbyoung; Ham, Hyunsun; Myung, Seungwoon [Kyonggi Univ., Suwon (Korea, Republic of)

    2013-07-01

    Lincomycin and Iopromide are major species among the Pharmaceuticals and Personal Care Products (PPCPs) from four major rivers in Korea. The structure characterization of six lincomycin's and two iopromide's degradation products formed under the irradiation of electron beam was performed, and the degradation efficiency as a function of the various irradiation dose and sample concentration was investigated. Electron beam (10 MeV, 0.5 mA and 5 kW) experiments for the structural characterization of the degradation products, which is fortified with lincomycin, were performed at the dose of 10 kGy. The separation of its degradation products and lincomycin was carried by C18 column (2.1 {Chi} 100 mm, 3.5 {mu}m), using gradient elution with 20 mM ammonium acetate and acetonitrile. The structures of degradation products of lincomycin and iopromide were proposed by interpretation of mass spectra and chromatograms by LC/MS/MS, and also the mass fragmentation pathways of mass spectra in tandem mass spectrometry were proposed. The experiments of the degradation efficiency as a function of the irradiation dose intensity and the initial concentration of lincomycin in aqueous environment were performed, and higher dose of electron beam and lower concentration was observed the increased degradation efficiency.

  10. Characterization of intermediate products of solar photocatalytic degradation of ranitidine at pilot-scale.

    Science.gov (United States)

    Radjenović, Jelena; Sirtori, Carla; Petrović, Mira; Barceló, Damià; Malato, Sixto

    2010-04-01

    In the present study the mechanisms of solar photodegradation of H(2)-receptor antagonist ranitidine (RNTD) were studied in a well-defined system of a pilot plant scale Compound Parabolic Collector (CPC) reactor. Two types of heterogeneous photocatalytic experiments were performed: catalysed by titanium-dioxide (TiO(2)) semiconductor and by Fenton reagent (Fe(2+)/H(2)O(2)), each one with distilled water and synthetic wastewater effluent matrix. Complete disappearance of the parent compounds and discreet mineralization were attained in all experiments. Furthermore, kinetic parameters, main intermediate products, release of heteroatoms and formation of carboxylic acids are discussed. The main intermediate products of photocatalytic degradation of RNTD have been structurally elucidated by tandem mass spectrometry (MS(2)) experiments performed at quadrupole-time of flight (QqToF) mass analyzer coupled to ultra-performance liquid chromatograph (UPLC). RNTD displayed high reactivity towards OH radicals, although a product of conduction band electrons reduction was also present in the experiment with TiO(2). In the absence of standards, quantification of intermediates was not possible and only qualitative profiles of their evolution could be determined. The proposed TiO(2) and photo-Fenton degradation routes of RNTD are reported for the first time.

  11. Ocular irritation from product of pesticide degradation among workers in a seed warehouse.

    Science.gov (United States)

    Matsukawa, Takehisa; Yokoyama, Kazuhito; Itoh, Hiroaki

    2015-01-01

    Four workers at a seed supply warehouse in Chiba Prefecture, Japan, complained of ocular irritation on the job. Pesticide-coated seeds were stored in the warehouse but no significant amount of pesticide was detected in the air inside the warehouse. To identify the cause of the ocular irritation and to determine an appropriate solution to the problem, the authors used thermal desorption gas chromatography-mass spectrometry to analyze the profiles of volatile organic compounds (VOCs) in the air of the two warehouses at the site-warehouse A, where the four workers experienced ocular irritation, and warehouse B, where no workers experienced ocular irritation. Comparing the profiles of VOCs in these warehouses indicated that n-butyl isocyanate, a hydrolyzed product of the fungicide benomyl, was the cause of the workers' ocular irritation. n-Butyl isocyanate is known to be a contact irritant and if the benomyl-coated seeds were not properly dried before storage in the warehouse n-butyl isocyanate would have been produced. The results of the study suggest that more attention should be paid both to the pesticide itself and to the products of pesticide degradation. In this study, n-butyl isocyanate was identified as a product of pesticide degradation and a causative chemical affecting occupational health.

  12. Identification and ecotoxicity of degradation products of chloroacetamide herbicides from UV-treatment of water

    DEFF Research Database (Denmark)

    Souissi, Yasmine; Bouchonnet, Stéphane; Bourcier, Sophie

    2013-01-01

    The widespread occurrence of chlorinated herbicides and their degradation products in the aquatic environment raises health and environmental concerns. As a consequence pesticides, and to a lesser degree their degradation products, are monitored by authorities both in surface waters and drinking...... and metolachlor increased the toxicity compared to the parent compounds while an equal toxicity was found for photolysis products of acetochlor. This suggests that toxic photodegradation products are generated from chloroacetamides under UV-treatment. An important perspective of this finding...... is that the photolysis products are at least as toxic as the parent compounds....

  13. Gaseous products generated by radiation degradation of N,N-diethylhydroxylamine aqueous solution

    Institute of Scientific and Technical Information of China (English)

    WANG Jinhua; WANG Shengxiu; BAO Borong; LI Zhen; LI Chun; ZHENG Weifang; ZHANG Shengdong

    2008-01-01

    In this paper, gaseous products generated by radiation degradation of N,N-diethylhydroxylamine (DEHA)in aqueous solution are studied. The results show that by 10~1000 kGy irradiation of the solution in DEHA volume fraction of hydrogen did not change much with different concentrations of DEHA. The volume fraction of methane and ethane decreased, but that of ethene increased, with increasing DEHA concentration. The volume fraction of hydrogen, methane and ethane increased with the dose. The relationship of the volume fraction of ethene with the dose had something to do with the DEHA concentration.

  14. Analytical and Experimental Studies of the Degradation in Hydrogenated Amorphous Silicon Solar Cells and Materials.

    Science.gov (United States)

    Yeung, Ping Fai

    1995-01-01

    An improved understanding of a-Si:H pin solar cells stability was obtained by studying light induced degradation in a-Si:H films and in devices. The current -voltage characteristics and the quantum efficiencies of a-Si:H pin solar cells were measured as a function of intrinsic layer thickness, bias light intensity and degradation condition. Photoconductivity measurements on device quality intrinsic a-Si:H thin film materials showed that the majority carrier (electron) mutau product degraded from 3times 10^{-7}rm cm ^2/V to 2times 10^{ -7}rm cm^2/V after 6 minutes of 50-Suns light illumination. Using a dual beam technique with steady white light and modulated monochromatic light, a degradation profile was detected in the degraded materials. These results suggest that inhomogeneous degradation may be important to understanding the stability of a-Si:H pin solar cells. An analytical model was developed for degradation in a-Si:H pin solar cells based on inhomogeneous degradation, which was used to explain the 'blue-dip' effect observed in the quantum efficiencies of degraded cells. A new method was developed to investigate the minority carrier (hole) diffusion length in device quality a-Si:H films as a function of degradation. This method uses the Schottky barrier structure to establish a depletion region, which can be controlled by the applied voltage and the bias light intensity. Modulated blue light is used to generate electron hole pairs near the ohmic contacts, and the holes diffuse across the neutral region to be collected. The modulated current is related to the diffusion length of the holes due to this current limiting hole transport. Comparing the results of this new technique to that of the Photocarrier Grating method, the electron drift mobility was found to degrade from rm 2.5cm^2/Vs to rm 0.15cm^2/Vs after 6 minutes of 50-Suns degradation.

  15. Toxicity and physical properties of atrazine and its degradation products: A literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Pugh, K.C.

    1994-10-01

    The Tennessee Valley Authority`s Environmental Research Center has been developing a means of detoxifying atrazine waste waters using TiO{sub 2} photocatalysis. The toxicity and physical properties of atrazine and its degradation products will probably be required information in obtaining permits from the United States Environmental Protection Agency for the demonstration of any photocatalytic treatment of atrazine waste waters. The following report is a literature survey of the toxicological and physical properties of atrazine and its degradation products.

  16. Cases Studies of Irrigated Soil Degradation and Progradation

    Science.gov (United States)

    Zeyliger, Anatoly; Kust, German; Rozov, Sergey; Stoma, Galina

    2013-04-01

    Waterlogging and salination, along with interaction with other degradation processes, have not only caused the collapse of irrigation-based societies in the past, but are indeed threatening the viability of irrigation at present. The problem is global in scope. Decimation of natural ecosystems, deterioration of soil productivity depletion and pollution of water resources, and conflicts over dwindling supplies have become international problems closely linked with extension of irrigation development to large scale and associated impact to soil fertility and surrounding environment. Practical experience and scientific research done in the frame of FP6 DESIRE project provided an affirmative answer to the question - can irrigated agriculture be sustained for long time. In present contribution two case studies will be discussed and analysed in scope to compare different irrigation practises used for about 35 years and their impact to soil fertility. Investigated areas of both case studies are situated in the same Saratov Region of Russia at the left bank of middle part of Volga River with distance between about 100 km. First case study was developed during 2009-2010 by field trials at irrigated and surrounded areas of agricultural farms situated at Privolghskaya Irrigation System (Marksovsky District). Second case study was developed during summer of 2011 by field trial at experimental farm of research institute called VolgNIIGiM (Enghelsky District). During fields trail soil maps of both case studies were developed and compared with soil maps of the same areas done at 1970th before irrigation projects at both areas were started. Results of soil map comparison are showing that in the territory of first case study considerable soil degradation is taken place, but in the territory of the second case study a substantial soil progradation is taken place. Thus is supported by the time series of ground water monitoring at both irrigated areas. Obtained results will be

  17. Dependence of transformation product formation on pH during photolytic and photocatalytic degradation of ciprofloxacin.

    Science.gov (United States)

    Salma, Alaa; Thoröe-Boveleth, Sven; Schmidt, Torsten C; Tuerk, Jochen

    2016-08-05

    Ciprofloxacin (CIP) is a broad-spectrum antibiotic with five pH dependent species in aqueous medium, which makes its degradation behavior difficult to predict. For the identification of transformation products and prediction of degradation mechanisms, a new experimental concept making use of isotopically labeled compounds together with high resolution mass spectrometry was successfully established. The utilization of deuterated ciprofloxacin (CIP-d8) facilitated the prediction of three different degradation pathways and the corresponding degradation products, four of which were identified for the first time. Moreover, two molecular structures of previously reported transformation products were revised according to the mass spectra and product ion spectra of the deuterated transformation products. Altogether, 18 transformation products have been identified during the photolytic and photocatalytic reactions at different pH values (3, 5, 7 and 9). In this work the influence of pH on both reaction kinetics and degradation mechanism was investigated for direct ultraviolet photolysis (UV-C irradiation) and photocatalysis (TiO2/UV-C). It could be shown that the removal rates strongly depended on pH with highest removal rates at pH 9. A comparison with those at pH 3 clearly indicated that under acidic conditions ciprofloxacin cannot be easily excited by UV irradiation. We could confirm that the first reaction step for both oxidative treatment processes is mainly defluorination, followed by degradation at the piperazine ring of CIP.

  18. Institutions,policies and soil degradation:theoretical examinations and case studies in Southeast China

    Institute of Scientific and Technical Information of China (English)

    Tan Shuhao; Qu Futian; Huang Xanjin; Nico Heerink

    2004-01-01

    Southeast China is one of the severe soil degradation areas in China. This paper theoretically examines the impact of some important institutional arrangements and policies, like land management pattern, the rural off-farm employment, land property change and changes in prices of agricultural products,on soil degradation in this area. It further conducts some case studies to confirm the potential relationship between the institutions & policies and soil degradation, applying the surveyed and the second hand data, The paper at last makes some conclusions and proposes some suggestions on how to promote soil conservation by improving the ways of policy decision-making and the effects of policies on land use.

  19. Effect of caffeine concentration on biomass production, caffeine degradation, and morphology of Aspergillus tamarii.

    Science.gov (United States)

    Gutiérrez-Sánchez, G; Roussos, S; Augur, C

    2013-05-01

    The aim of the present study was to evaluate the effect of the initial caffeine concentration (1-8 g/L) on growth and caffeine consumption by Aspergillus tamarii as well as pellet morphology, in submerged fermentation. Caffeine was used as sole nitrogen source. At 1 g/L of initial caffeine concentration, caffeine degradation was not affected, resulting in a production of 8.7 g/L of biomass. The highest biomass production (12.4-14.8 g/L) was observed within a range of 2 to 4 g/L of initial caffeine concentration. At these initial caffeine concentrations, after 96 h of fermentation, 41-51 % of the initial caffeine was degraded. Using an initial caffeine concentration of 2-3 g/L, the highest specific growth rate was observed (μ = 0.069 1/h). Biomass production decreased at 8 g/L of initial caffeine concentration. A. tamarii formed mainly pellets at all concentrations tested. The size of the pellet decreased at a caffeine concentration of 8 g/L.

  20. Estimation of PMI depends on the changes in ATP and its degradation products.

    Science.gov (United States)

    Mao, Shiwei; Fu, Gaowen; Seese, Ronald R; Wang, Zhen-Yuan

    2013-09-01

    Estimating the time since death, or postmortem interval (PMI), has been one of the biggest difficulties in modern forensic investigation. This study tests if the concentrations of breakdown products of adenosine triphosphate (ATP) correlate with PMI in multiple organs from rat. Brains, spleens, and kidneys of rats were harvested at different time points in carcasses maintained at 4°C or 20°C. High Performance Liquid Chromatography (HPLC) was used to quantify concentrations of metabolites related to ATP degradation. A K value (Kv=100×(Hx+HxR)/(ATP+ADP+AMP+IMP+HxR+Hx)) was calculated and correlated with PMI for each organ and temperature. The results indicate that the K value is a robust index for the estimation of PMI based on highly significant linear correlations between PMI and concentrations of ATP breakdown products. Compared with other current research methods, the changing tendency of ATP and its degradation products may be potentially a better way for the estimation of PMI in medico-legal practice. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. Degradation in photoelectrochemical devices: review with an illustrative case study

    Science.gov (United States)

    Nandjou, Fredy; Haussener, Sophia

    2017-03-01

    The durability, reliability, and robustness of photoelectrochemical (PEC) devices are key factors for advancing the practical large-scale implementation of cost-competitive solar fuel production. We review the known degradation mechanisms occurring in water-splitting photoelectrochemical devices. The degradation of single components is discussed in detail, and the parameters and conditions which influence it are presented. Device short-term durability depends on the semiconductor material and its interface with the electrolyte. Catalyst and electrolyte degradations are considerable challenges for long-term durability. We highlight how PEC device design choices can affect the salience of alternative degradation mechanisms. The PEC device architecture and the initial operating design point are crucial for observed device performance loss. Device degradation behavior is further impacted by irradiation intensity and concentration, and by current density and concentration. Enhancing a physical understanding of degradation phenomena and investigating their effect on component properties is of utmost importance for predicting performance loss and tackling the durability challenge of PEC devices.

  2. Degradation of atrazine in aqueous medium by electrocatalytically generated hydroxyl radicals. A kinetic and mechanistic study.

    Science.gov (United States)

    Balci, Beytul; Oturan, Nihal; Cherrier, Richard; Oturan, Mehmet A

    2009-04-01

    Oxidative degradation of atrazine by hydroxyl radicals (()OH) was studied in aqueous medium. ()OH were formed in situ from electrochemically generating Fenton's reagent by an indirect electrochemical advanced oxidation process. Identification and evolution of seven main aromatic metabolites and four short-chain carboxylic acids were performed by using liquid chromatography analyses. Total organic carbon (TOC) and ionic chromatography were used in order to evaluate the mineralization efficiency of treated aqueous solutions. A high mineralization rate of 82% (never reported until now) was obtained. The oxidative degradation of cyanuric acid, the ultimate product of atrazine degradation, was highlighted for the first time. The absolute rate constant of the reaction between atrazine and hydroxyl radicals was evaluated by competition kinetics method as (2.54+/-0.22)x10(9)M(-1)s(-1). Considering all oxidation reaction intermediates and end products a general reaction sequence for atrazine degradation by hydroxyl radicals was proposed.

  3. Fast in vitro hydrolytic degradation of polyester urethane acrylate biomaterials: Structure elucidation, separation and quantification of degradation products

    NARCIS (Netherlands)

    Ghaffar, A.; Verschuren, P.G.; Geenevasen, J.A.J.; Handels, T.; Berard, J.; Plum, B.; Dias, A.A.; Schoenmakers, P.J.; van der Wal, S.

    2011-01-01

    Synthetic biomaterials have evoked extensive interest for applications in the field of health care. Prior to administration to the body a quantitative study is necessary to evaluate their composition. An in vitro method was developed for the quick hydrolytic degradation of poly-2-hydroxyethyl methac

  4. EDS and μ-XRF mapping of amalgam degradation products in ancient mirrors.

    Science.gov (United States)

    Arizio, E; Orsega, E F; Falcone, R; Vallotto, M

    2014-12-01

    An amalgam mirror is a mirror type, used from the fifteenth century until the end of the nineteenth century, where the reflective layer is constituted by a tin amalgam layer adhered to a glass sheet. In this work, two amalgam mirrors samples were studied by scanning electron microscopy with an energy dispersive spectrometer and by micro-X-ray fluorescence elemental mapping to go deeply into the understanding of the degradation mechanism of the amalgam layer of ancient mirrors. The investigation has been focused for the first time on the reflective surface of the amalgam layer adherent to the glass sheet to better understand the processes of amalgam corrosion. The two amalgam degradation compounds, romarchite and cassiterite, has been spatially differentiated by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) maps. SEM images and micro-X-ray fluorescence and EDS maps showed that the amalgam degradation products grow up to form hemispherical stratified calottes. This structure is probably due to a mechanism involves cyclic phases and oxygen radial diffusion from a superficial oxidation nucleus.

  5. The Production of Solid Dosage Forms from Non-Degradable Polymers.

    Science.gov (United States)

    Major, Ian; Fuenmayor, Evert; McConville, Christopher

    2016-01-01

    Non-degradable polymers have an important function in medicine. Solid dosage forms for longer term implantation require to be constructed from materials that will not degrade or erode over time and also offer the utmost biocompatibility and biostability. This review details the three most important non-degradable polymers for the production of solid dosage forms - silicone elastomer, ethylene vinyl acetate and thermoplastic polyurethane. The hydrophobic, thermoset silicone elastomer is utilised in the production of a broad range of devices, from urinary catheter tubing for the prevention of biofilm to intravaginal rings used to prevent HIV transmission. Ethylene vinyl acetate, a hydrophobic thermoplastic, is the material of choice of two of the world's leading forms of contraception - Nuvaring® and Implanon®. Thermoplastic polyurethane has such a diverse range of building blocks that this one polymer can be hydrophilic or hydrophobic. Yet, in spite of this versatility, it is only now finding utility in commercialised drug delivery systems. Separately then one polymer has a unique ability that differentiates it from the others and can be applied in a specific drug delivery application; but collectively these polymers provide a rich palette of material and drug delivery options to empower formulation scientists in meeting even the most demanding of unmet clinical needs. Therefore, these polymers have had a long history in controlled release, from the very beginning even, and it is pertinent that this review examines briefly this history while also detailing the state-of-the-art academic studies and inventions exploiting these materials. The paper also outlines the different production methods required to manufacture these solid dosage forms as many of the processes are uncommon to the wider pharmaceutical industry.

  6. Evaluating the Potential Importance of Monoterpene Degradation for Global Acetone Production

    Science.gov (United States)

    Kelp, M. M.; Brewer, J.; Keller, C. A.; Fischer, E. V.

    2015-12-01

    Acetone is one of the most abundant volatile organic compounds (VOCs) in the atmosphere, but estimates of the global source of acetone vary widely. A better understanding of acetone sources is essential because acetone serves as a source of HOx in the upper troposphere and as a precursor to the NOx reservoir species peroxyacetyl nitrate (PAN). Although there are primary anthropogenic and pyrogenic sources of acetone, the dominant acetone sources are thought to be from direct biogenic emissions and photochemical production, particularly from the oxidation of iso-alkanes. Recent work suggests that the photochemical degradation of monoterpenes may also represent a significant contribution to global acetone production. We investigate that hypothesis using the GEOS-Chem chemical transport model. In this work, we calculate the emissions of eight terpene species (α-pinene, β-pinene, limonene, Δ3-carene, myrcene, sabinene, trans-β-ocimene, and an 'other monoterpenes' category which contains 34 other trace species) and couple these with upper and lower bound literature yields from species-specific chamber studies. We compare the simulated acetone distributions against in situ acetone measurements from a global suite of NASA aircraft campaigns. When simulating an upper bound on yields, the model-to-measurement comparison improves for North America at both the surface and in the upper troposphere. The inclusion of acetone production from monoterpene degradation also improves the ability of the model to reproduce observations of acetone in East Asian outflow. However, in general the addition of monoterpenes degrades the model comparison for the Southern Hemisphere.

  7. Dependence of transformation product formation on pH during photolytic and photocatalytic degradation of ciprofloxacin

    Energy Technology Data Exchange (ETDEWEB)

    Salma, Alaa [Institut für Energie- und Umwelttechnik e. V. (IUTA, Institute of Energy and Environmental Technology), Bliersheimer Straße 58-60, 47229 Duisburg (Germany); Thoröe-Boveleth, Sven [University Hospital Aachen, Institute for Hygiene and Environmental Medicine, Pauwelsstraße 30, 52074 Aachen (Germany); Schmidt, Torsten C. [University Duisburg-Essen, Faculty of Chemistry, Instrumental Analytical Chemistry, Universitätsstraße 5, 45141 Essen (Germany); Centre for Water and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstraße 2, 45141 Essen (Germany); Tuerk, Jochen, E-mail: tuerk@iuta.de [Institut für Energie- und Umwelttechnik e. V. (IUTA, Institute of Energy and Environmental Technology), Bliersheimer Straße 58-60, 47229 Duisburg (Germany); Centre for Water and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstraße 2, 45141 Essen (Germany)

    2016-08-05

    Highlights: • Identification of transformation products using an isotopically labeled surrogate. • 4 of 18 detected transformation products have been identified for the first time. • Revision of 2 molecular structures of previously reported transformation products. • PH dependence of photolytic and photocatalytic degradation of ciprofloxacin. - Abstract: Ciprofloxacin (CIP) is a broad-spectrum antibiotic with five pH dependent species in aqueous medium, which makes its degradation behavior difficult to predict. For the identification of transformation products and prediction of degradation mechanisms, a new experimental concept making use of isotopically labeled compounds together with high resolution mass spectrometry was successfully established. The utilization of deuterated ciprofloxacin (CIP-d8) facilitated the prediction of three different degradation pathways and the corresponding degradation products, four of which were identified for the first time. Moreover, two molecular structures of previously reported transformation products were revised according to the mass spectra and product ion spectra of the deuterated transformation products. Altogether, 18 transformation products have been identified during the photolytic and photocatalytic reactions at different pH values (3, 5, 7 and 9). In this work the influence of pH on both reaction kinetics and degradation mechanism was investigated for direct ultraviolet photolysis (UV-C irradiation) and photocatalysis (TiO{sub 2}/UV-C). It could be shown that the removal rates strongly depended on pH with highest removal rates at pH 9. A comparison with those at pH 3 clearly indicated that under acidic conditions ciprofloxacin cannot be easily excited by UV irradiation. We could confirm that the first reaction step for both oxidative treatment processes is mainly defluorination, followed by degradation at the piperazine ring of CIP.

  8. Kinetic studies of novel inhibitors of endomorphin degrading enzymes

    OpenAIRE

    Perlikowska, Renata; Fichna, Jakub; do-Rego, Jean Claude; Gach, Katarzyna; Janecka, Anna

    2011-01-01

    Endomorphins (EMs), two endogenous μ-opioid receptor selective ligands, are attractive lead compounds for opioid-based pain management studies. However, these peptides are quickly degraded by peptidases, in particular by dipeptidylpeptidase IV (DPP IV) and aminopeptidase M (APM). Targeting enzymatic degradation is one approach to prolong endomorphin activity. In this study we characterized the action of two new inhibitors of similar to endomorphins structure, Tyr-Pro-Ala-NH2 (EMDB-2) and Tyr-...

  9. A thermal degradation study of Y and La methanesulfonates

    OpenAIRE

    MATOS, JIVALDO do R.; ROBSON F. DE FARIAS

    2006-01-01

    The synthesis, characterization and thermal degradation of yttrium and lanthanum methanesulfonates is reported. The prepared salts were characterized by elemental analysis and infrared spectroscopy. The thermal degradation study was performed using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC).Using the thermogravimetric data, a kinetic study of the dehydration ofY and Lamethanesulfonates was performed employing the Coats–Redfern and Zs...

  10. A degradation study of PLLA containing lauric acid.

    Science.gov (United States)

    Renouf-Glauser, Annette C; Rose, John; Farrar, David; Cameron, Ruth E

    2005-05-01

    Addition of lauric acid to poly (L-lactide) (PLLA) has resulted in a new family of enhanced degradation biomaterials. Presented is PLLA4.5 (PLLA containing 4.5 wt% lauric acid), the fastest degrading of the family. Degradation was studied via mass changes, gel-permeation chromatography, wide- and small-angle X-ray scattering (WAXS and SAXS), simultaneous SAXS and tensile testing, and visual observation. The undegraded PLLA4.5 deformed by crazing, recognisable from the characteristic shape of the SAXS pattern. As water up-take and degradation proceeded, samples crystallised, decreasing the SAXS long period, until by 4 days the deformation mechanism had become that of crystal-mediated deformation. This resulted in a 'peanut-lemon'-shaped SAXS pattern, interpreted in terms of cavitation and fibrillated shear. Further degradation up to 12 days resulted in the same deformation mechanism at different sample displacements, with samples failing earlier during tensile testing until a ductile-brittle transition occurred. At 30-40 days water up-take and mass-loss increased significantly and global whitening of samples occurred, while the crystallinity and long period stabilised. Complete degradation had not occurred by the end of the study at 73 days. Through an understanding of how the changes in morphology during degradation affect the micromechanisms of deformation, it may be possible to design microstructures to give a tailored evolution of mechanical response in the body.

  11. Mechanism driven structural elucidation of forced degradation products from hydrocortisone in solution.

    Science.gov (United States)

    Zhang, Fa; Zhou, Jay; Shi, Yiqun; Tavlarakis, Panagiotis; Karaisz, Kenneth

    2016-09-01

    Hydrocortisone degradation products 1, 2, 3, and 4 along with hemiacetal derivatives 5, 6, 7, and 8 were observed through stressed hydrocortisone in solution. Their structures were identified based on HPLC-UV, HPLC-MS, and HPLC-HRMS (high resolution/high accuracy mass spectrometry) analyses as well as reaction mechanistic investigation and synthesis for structural confirmation. 1 and 2 are a pair of E/Z isomers and they were generated through acid catalyzed tautomerization/dehydration of hydrocortisone. Incorporation of water to 1 and 2 resulted in the formation of 3. We also discovered new degradation product 4 which was converted from 3 by oxidation. The degradation products were synthesized by stressing hydrocortisone under the optimized conditions and their structures were characterized by NMR ((1)H/(13)C, COSY, HMBC, HSQC, NOESY) and HRMS analyses. The degradation pathway of hydrocortisone is postulated.

  12. Preliminary Studies on Chlorimuron Degradation in Soil by Effective Microogranisms

    Institute of Scientific and Technical Information of China (English)

    LIU Yaguang

    2006-01-01

    A wheat (Triticum aestivum L.) bioassay method was used for preliminary determination of chlorimuron degradation in soil by EM (effective microorganisms). Under the conditions of this study, chlorimuron half-life was greater than 30-50 days in soil containing different initial concentrations of chlorimuron. After adding EM, chlorimuron degradation half-life ranged from 10-15 days, which was about 15-30 days shorter than without EM. Chlorimuron phate and urea enhanced the ability of EM to degrade chlorimuron, but brown sugar had no significant effect.

  13. Structural Studies of Biomass Degrading Enzyme Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lunin, Vladimir V.; Alahuhta, Markus; Brunecky, Roman; Donohoe, Bryon; Xu, Qi; Bomble, Yannick J.; Himmel, Michael E.

    2014-08-05

    Renewable energy today comprises wind, photovoltaics, geothermal, and biofuels. Biomass is the leading source of renewable, sustainable energy used for the production of liquid transportation fuels. While the focus is shifting today from the ethanol towards next generation or advanced biofuels the real challenge however remains the same: reducing the recalcitrance of biomass to deconstruction, which yields the sugars needed for further processing.

  14. Kinetic and mechanistic study of microcystin-LR degradation by nitrous acid under ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qingwei; Ren, Jing [Department of Environmental Science and Engineering, Fudan University, Shanghai 200433 (China); Huang, Honghui [Key Laboratory of Fisheries Ecology Environment, Ministry of Agriculture, Guangzhou 510300 (China); Wang, Shoubing [Department of Environmental Science and Engineering, Fudan University, Shanghai 200433 (China); Wang, Xiangrong, E-mail: xrxrwang@vip.sina.com [Department of Environmental Science and Engineering, Fudan University, Shanghai 200433 (China); Fan, Zhengqiu, E-mail: zhqfan@fudan.edu.cn [Department of Environmental Science and Engineering, Fudan University, Shanghai 200433 (China)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer For the first time, degradation of MC-LR by nitrous acid under UV 365 nm was discovered. Black-Right-Pointing-Pointer The effects of factors on MC-LR degradation were analyzed based on kinetic study. Black-Right-Pointing-Pointer Mass spectrometry was applied for identification of intermediates and products. Black-Right-Pointing-Pointer Special intermediates involved in this study were identified. Black-Right-Pointing-Pointer Degradation mechanisms were proposed according to the results of LC-MS analysis. - Abstract: Degradation of microcystin-LR (MC-LR) in the presence of nitrous acid (HNO{sub 2}) under irradiation of 365 nm ultraviolet (UV) was studied for the first time. The influence of initial conditions including pH value, NaNO{sub 2} concentration, MC-LR concentration and UV intensity were studied. MC-LR was degraded in the presence of HNO{sub 2}; enhanced degradation of MC-LR was observed with 365 nm UV irradiation, caused by the generation of hydroxyl radicals through the photolysis of HNO{sub 2}. The degradation processes of MC-LR could well fit the pseudo-first-order kinetics. Mass spectrometry was applied for identification of the byproducts and the analysis of degradation mechanisms. Major degradation pathways were proposed according to the results of LC-MS analysis. The degradation of MC-LR was initiated via three major pathways: attack of hydroxyl radicals on the conjugated carbon double bonds of Adda, attack of hydroxyl radicals on the benzene ring of Adda, and attack of nitrosonium ion on the benzene ring of Adda.

  15. Ensiling Characteristics and the Nutrient Degradability of a By-product Feed-based Silage

    Directory of Open Access Journals (Sweden)

    Y. I. Kim

    2014-02-01

    Full Text Available This study was conducted to evaluate the ensiling characteristics and the in situ degradability of a by-product feed (BF-based silage. Before ensilation, the BF-based mixture was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial inoculant on a wet basis and ensiled for up to 4 weeks. The BF-based silage contained on average 39.3% moisture, 13.4% crude protein (CP, and 52.2% neutral detergent fiber (NDF, 49% total digestible nutrient, and 37.8% physically effective NDF1.18 on a dry matter (DM basis. Ensiling the BF-based silage for up to 4 weeks affected (p<0.01 the chemical composition to a small extent, increased (p<0.05 the lactic acid and NH3-N content, and decreased (p<0.05 both the total bacterial and lactic acid bacterial counts from 109 to 108 cfu/g when compared to that before ensiling. These parameters indicated that the silage was fermented and stored well during the 4-week ensiling period. Compared with rice or ryegrass straws, the BF-based silage had a higher (p<0.05 water-soluble and filterable fraction, a lower insoluble degradable DM and CP fraction (p<0.05, a lower digestible NDF (p<0.05 fraction, a higher (p<0.05 DM and CP disappearance and degradability rate, and a lower (p<0.05 NDF disappearance and degradability rate. These results indicated that cheap, good-quality BF-based roughage could be produced by ensiling SMS, RPB, rice bran, and a minimal amount of straw.

  16. Degradation of 2,4-dichlorophenoxyacetic acid by a halotolerant strain of Penicillium chrysogenum: antibiotic production.

    Science.gov (United States)

    Ferreira-Guedes, Sumaya; Mendes, Benilde; Leitão, Ana Lúcia

    2012-01-01

    The extensive use of pesticides in agriculture has prompted intensive research on chemical and biological methods in order to protect contamination of water and soil resources. In this paper the degradation of the pesticide 2,4-dichlorophenoxyacetic acid by a Penicillium chrysogenum strain previously isolated from a salt mine was studied in batch cultures. Co-degradation of 2,4-dichlorophenoxyacetic acid with additives such as sugar and intermediates of pesticide metabolism was also investigated. Penicillium chrysogenum in solid medium was able to grow at concentrations up to 1000 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D) with sucrose. Meanwhile, supplementation of the solid medium with glucose and lactose led to fungal growth at concentrations up to 500 mg/L of herbicide. Batch cultures of 2,4-D at 100 mg/L were developed under aerobic conditions with the addition of glucose, lactose and sucrose, showing sucrose as the best additional carbon source. The 2,4-D removal was quantified by liquid chromatography. The fungus was able to use 2,4-D as the sole carbon and energy source under 0%, 2% and 5.9% NaCl. The greatest 2,4-D degradation efficiency was found using alpha-ketoglutarate and ascorbic acid as co-substrates under 2% NaCl at pH 7. Penicillin production was evaluated in submerged cultures by bioassay, and higher amounts of beta-lactam antibiotic were produced when the herbicide was alone. Taking into account the ability of P. chrysogenum CLONA2 to degrade aromatic compounds, this strain could be an interesting tool for 2,4-D herbicide remediation in saline environments.

  17. IN-VIVO DEGRADATION AND BIOCOMPATIBILITY STUDY OF IN-VITRO PRE-DEGRADED AS-POLYMERIZED POLYLACTIDE PARTICLES

    NARCIS (Netherlands)

    BERGSMA, JE; ROZEMA, FR; BOS, RRM; BOERING, G; DEBRUIJN, WC; PENNINGS, AJ

    1995-01-01

    The degradation of high molecular weight as-polymerized poly(L-lactide) (PLLA) is very slow; it takes more than 5.6 yr for total resorption. Moreover, the degradation products of as-polymerized PLLA bone plates, consisting of numerous stable particles of high crystallinity, are related with a subcut

  18. [Removal of triclosan with the method of UV/ClO2 and its degradation products].

    Science.gov (United States)

    Li, Yu-Ying; He, Wen-Long; Li, Qing-Song; Jin, Wei-Wei; Chen, Guo-Yuan; Li, Guo-Xin

    2015-02-01

    The UV/ClO2 process for triclosan ( TCS) removal was studied. The influences of several factors such as the initial pH, dose of ClO2, initial concentration of TCS and humic acid( HA) on TCS degradation in the UV/ClO2 combined process were discussed. The results showed that the UV/ClO2 process could effectively remove TCS and had a synergistic effect. When the light intensity was 6.5 μW x Cm(-2), the dose of ClO2 was 0. 5 mg x L(-1) and the concentration of TCS was 300 μg x L(-1), when UV and ClO2 were applied alone, the TCS removal rates within 1 min were only 5.23% and 84.93% respectively. The removal rate reached up to 99.13% after 1 min degradation using the UV/ClO2 combined process. In test conditions ( pH 6-9), the removal rate increased from 99.4% to 99. 63% with the increase of pH. Increasing dose of CIO2 could promote TCS removal. When the dose of ClO2 was 0.5-1.5 mg x L(-1), the removal rate was increased from 98.1% to 99.89%. The initial concentration of TCS was negatively correlated with the removal rate. When the initial concentration increased from 100 - 500 μg x L(-1), the removal rate of TCS was decreased from 99.98% to 94.39%. Low concentration of humic acid was beneficial to the removal of TCS, and high concentration of it had the opposite effect. Degradation products of TCS were investigated by GC/MS. Degradation of TCS by the processes of UV, ClO2 and UV/ClO2 also indicated that the main degradation products of the TCS were 2, 4-dichlorophenol (2,4-DCP), 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD), etc.

  19. Simultaneous determination of sulpiride and its alkaline degradation product by second derivative synchronous fluorescence spectroscopy.

    Science.gov (United States)

    Abdelal, Amina; El-Enany, Nahed; Belal, Fathalla

    2009-12-15

    Simple and sensitive synchronous fluorimetric, and second derivative synchronous fluorometric methods were developed for the validated and simultaneous determination of sulpiride (SLP) and its alkaline degradation product (DSLP). The method is based on measuring the synchronous fluorescence of both the drug and its degradation product in borate buffer of pH 8 at Deltalambda of 45 nm. The peak amplitude ((2)D) was measured at 295.5 and 342 nm for SLP and DSLP, respectively. The different experimental parameters affecting the synchronous fluorescence intensity of both compounds were studied and optimized. The fluorescence-concentration plots were rectilinear over the range of 0.05-1.0 and 2-10 microg mL(-1) for SLP and DSLP, respectively. The limits of detection (LOD) were 0.02 and 0.4 microg mL(-1) and quantification limits (LOQs) were 0.05 and 1.2 microg mL(-1) for SLP and DSLP, respectively. The proposed methods were successfully applied to commercial capsules and tablets. Statistical comparison of the results with those of the official method revealed good agreement and proved that there were no significant difference in the accuracy and precision between the two methods, respectively. The method was utilized to study the kinetics of the alkaline induced degradation of the drug. The application was further extended to include the in vivo and in vitro determination of sulpiride. The mean % recoveries (n=3) were 100.22+/-2.04 and 92.00+/-3.00 for spiked and real human plasma, respectively.

  20. Isolation and identification of oil sludge degrading bacteria from production tank Number 9 Masjed Soleiman

    Directory of Open Access Journals (Sweden)

    Yalda Sheyni

    2014-07-01

    Full Text Available   Introduction: “Bioremediation” is one of the most effective methods to remove petroleum contaminants. The aim of the present study is to isolate the indigenous bacteria from the waste petroleum in the Masjed Soleiman No. 9 production tank and to examine the effect of their application on the elimination of petroleum heavy chain hydrocarbons and converting them into light compounds .   Materials and methods: Two percent of petroleum sludge was inoculated to the mineral basal medium and after proliferation of its indigenous bacteria, they were inoculated into the mixture of oil sludge and sand at level of 5%, and the amount of total hydrocarbons and residual oil were measured and compared. The isolates were identified based on biochemical tests and 16S rRNA gene sequencing. Optimization of nitrogen and phosphate sources was done based on growth curves of selected isolates. Gas chromatography was used to determine degradation of sludge hydrocarbons.   Results: In this study, 10 bacterial isolates were isolated from petroleum sludge . Measurement of petroleum total hydrocarbons, using Soxhlet-extraction method, showed that two isolates named MIS1 and MIS2 are able to decompose oil sludge hydrocarbons within 7 days, with the yields of 62% and 72%, respectively. Furthermore, the two isolates reach the end of the logarithmic phase at 48 and 120 hrs, respectively. The best source of nitrogen and phosphate for both isolates was ammonium nitrate and potassium di ­hydrogen phosphate, respectively. The isolates were identified as Arthrobacter aurescens and Pseudomonas aeruginosa , respectively. In gas chromatography analysis it was revealed that Pseudomonas aeruginosa was more potent in degradation of heavy chain hydrocarbons and their conversion to light chain compounds.   Discussion and conclusion: Resident bacteria are present in the oil sludge and are able to degrade the heavy petroleum compounds and convert them into light compounds. These

  1. Studies on the sonic degradation of deoxyribonucleic acid.

    Science.gov (United States)

    FREIFELDER, D; DAVISON, P F

    1962-05-01

    T7 DNA was partially degraded by x-rays, DNAase, and sonic irradiation. The molecular weight distributions were calculated from sedimentation velocity studies on the resulting preparations. Comparison with the theoretical curve derived by Montroll and Simha showed that the first two degradative methods act grossly at random, whereas sonication is a non-random process resulting in the preferential halving of the DNA molecules in solution.

  2. Effect of chlorine dioxide on cyanobacterial cell integrity, toxin degradation and disinfection by-product formation.

    Science.gov (United States)

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Li, Lei; Deng, Jing; Zhu, Mingqiu; Zhu, Shumin

    2014-06-01

    Bench scale tests were conducted to study the effect of chlorine dioxide (ClO2) oxidation on cell integrity, toxin degradation and disinfection by-product formation of Microcystis aeruginosa. The simulated cyanobacterial suspension was prepared at a concentration of 1.0×10(6)cells/mL and the cell integrity was measured with flow cytometry. Results indicated that ClO2 can inhibit the photosynthetic capacity of M. aeruginosa cells and almost no integral cells were left after oxidation at a ClO2 dose of 1.0mg/L. The total toxin was degraded more rapidly with the ClO2 dosage increasing from 0.1mg/L to 1.0mg/L. Moreover, the damage on cell structure after oxidation resulted in released intracellular organic matter, which contributed to the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) as disinfection by-products. Therefore, the use of ClO2 as an oxidant for treating algal-rich water should be carefully considered.

  3. Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis

    Institute of Scientific and Technical Information of China (English)

    Cheng-gang CAI; Bing-gan LOU; Xiao-dong ZHENG

    2008-01-01

    A new feather-degrading bacterium was isolated from a local feather waste site and identified as Bacillus subtilis based on morphological, physiochemical, and phylogenetic characteristics. Screening for mutants with elevated keratinolytic activity using N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis resulted in a mutant strain KD-N2 producing keratinolytic activity about 2.5 times that of the wild-type strain. The mutant strain produced inducible keratinase in different substrates of feathers, hair, wool and silk under submerged cultivation. Scanning electron microscopy studies showed the degradation of feathers, hair and silk by the keratinase. The optimal conditions for keratinase production include initial pH of 7.5, inoculum size of 2% (v/v), age of inoculum of 16 h, and cultivation at 23 ℃. The maximum keratinolytic activity of KD-N2 was achieved after 30 h. Essential amino acids like threonine, valine, methionine as well as ammonia were produced when feathers were used as substrates. Strain KD-N2,therefore, shows great promise of finding potential applications in keratin hydrolysis and keratinase production.

  4. Subcritical water hydrolysis of rice straw for reducing sugar production with focus on degradation by-products and kinetic analysis.

    Science.gov (United States)

    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Qi, Feng; Zhou, Junhu; Cen, Kefa

    2015-06-01

    The competitive reactions of reducing sugar production and degradation in the subcritical water hydrolysis of rice straw were investigated to optimise reducing sugar yield. The optimised conditions (280°C, 20 MPa, rice straw concentration of 5 wt.% and agitation speed of 200 rpm) resulted in a reducing sugar yield of 0.346 g/g rice straw because of the enhanced reducing sugar production and decreased sugar degradation. The sugar yield increased when the temperature increased from 250°C to 280°C, but it decreased when the temperature further increased to 300°C because of the degradation of monosaccharides (e.g. glucose and xylose) into by-products (e.g. 2-methyltetrahydrofuran and acetic acid). A first-order reaction model was developed to elucidate the competitive reaction kinetics of sugar production and degradation at various temperatures. The highest reducing sugar yield based on the model was achieved at 280°C with the highest production and lowest degradation rates.

  5. Identification of forced degradation products of itopride by LC-PDA and LC-MS

    Directory of Open Access Journals (Sweden)

    Payal Joshi

    2011-01-01

    Full Text Available Degradation products of itopride formed under different forced conditions have been identified using LC-PDA and LC-MS techniques. Itopride was subjected to forced degradation under the conditions of hydrolysis, photolysis, oxidation, dry and wet heat, in accordance with the International Conference on Harmonization. The stress solutions were chromatographed on reversed phase C18 (250×4.6 mm, 5 μm column with a mobile phase methanol:water (55:45, v/v at a detection wavelength of 215 nm. Itopride degraded in acid, alkali and oxidative stress conditions. The stability indicating method was developed and validated. The degradation pathway of the drug to products II-VIII is proposed.

  6. Analyzing insulin samples by size-exclusion chromatography: a column degradation study.

    Science.gov (United States)

    Teska, Brandon M; Kumar, Amit; Carpenter, John F; Wempe, Michael F

    2015-04-01

    Investigating insulin analogs and probing their intrinsic stability at physiological temperature, we observed significant degradation in the size-exclusion chromatography (SEC) signal over a moderate number of insulin sample injections, which generated concerns about the quality of the separations. Therefore, our research goal was to identify the cause(s) for the observed signal degradation and attempt to mitigate the degradation in order to extend SEC column lifespan. In these studies, we used multiangle light scattering, nuclear magnetic resonance, and gas chromatography-mass spectrometry methods to evaluate column degradation. The results from these studies illustrate: (1) that zinc ions introduced by the insulin product produced the observed column performance issues; and (2) that including ethylenediaminetetraacetic acid, a zinc chelator, in the mobile phase helped to maintain column performance.

  7. Recombinant protein production facility for fungal biomass-degrading enzymes using the yeast Pichia pastoris

    Science.gov (United States)

    Haon, Mireille; Grisel, Sacha; Navarro, David; Gruet, Antoine; Berrin, Jean-Guy; Bignon, Christophe

    2015-01-01

    Filamentous fungi are the predominant source of lignocellulolytic enzymes used in industry for the transformation of plant biomass into high-value molecules and biofuels. The rapidity with which new fungal genomic and post-genomic data are being produced is vastly outpacing functional studies. This underscores the critical need for developing platforms dedicated to the recombinant expression of enzymes lacking confident functional annotation, a prerequisite to their functional and structural study. In the last decade, the yeast Pichia pastoris has become increasingly popular as a host for the production of fungal biomass-degrading enzymes, and particularly carbohydrate-active enzymes (CAZymes). This study aimed at setting-up a platform to easily and quickly screen the extracellular expression of biomass-degrading enzymes in P. pastoris. We first used three fungal glycoside hydrolases (GHs) that we previously expressed using the protocol devised by Invitrogen to try different modifications of the original protocol. Considering the gain in time and convenience provided by the new protocol, we used it as basis to set-up the facility and produce a suite of fungal CAZymes (GHs, carbohydrate esterases and auxiliary activity enzyme families) out of which more than 70% were successfully expressed. The platform tasks range from gene cloning to automated protein purifications and activity tests, and is open to the CAZyme users’ community. PMID:26441929

  8. Progressive degradation of crude oil n-alkanes coupled to methane production under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Cheng, Lei; Shi, Shengbao; Li, Qiang; Chen, Jianfa; Zhang, Hui; Lu, Yahai

    2014-01-01

    Although methanogenic degradation of hydrocarbons has become a well-known process, little is known about which crude oil tend to be degraded at different temperatures and how the microbial community is responded. In this study, we assessed the methanogenic crude oil degradation capacity of oily sludge microbes enriched from the Shengli oilfield under mesophilic and thermophilic conditions. The microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes combined with cloning and sequencing. Enrichment incubation demonstrated the microbial oxidation of crude oil coupled to methane production at 35 and 55°C, which generated 3.7±0.3 and 2.8±0.3 mmol of methane per gram oil, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that crude oil n-alkanes were obviously degraded, and high molecular weight n-alkanes were preferentially removed over relatively shorter-chain n-alkanes. Phylogenetic analysis revealed the concurrence of acetoclastic Methanosaeta and hydrogenotrophic methanogens but different methanogenic community structures under the two temperature conditions. Candidate divisions of JS1 and WWE 1, Proteobacteria (mainly consisting of Syntrophaceae, Desulfobacteraceae and Syntrophorhabdus) and Firmicutes (mainly consisting of Desulfotomaculum) were supposed to be involved with n-alkane degradation in the mesophilic conditions. By contrast, the different bacterial phylotypes affiliated with Caldisericales, "Shengli Cluster" and Synergistetes dominated the thermophilic consortium, which was most likely to be associated with thermophilic crude oil degradation. This study revealed that the oily sludge in Shengli oilfield harbors diverse uncultured microbes with great potential in methanogenic crude oil degradation over a wide temperature range, which extend our previous understanding of methanogenic degradation of crude oil alkanes.

  9. Progressive degradation of crude oil n-alkanes coupled to methane production under mesophilic and thermophilic conditions.

    Directory of Open Access Journals (Sweden)

    Lei Cheng

    Full Text Available Although methanogenic degradation of hydrocarbons has become a well-known process, little is known about which crude oil tend to be degraded at different temperatures and how the microbial community is responded. In this study, we assessed the methanogenic crude oil degradation capacity of oily sludge microbes enriched from the Shengli oilfield under mesophilic and thermophilic conditions. The microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP analysis of 16S rRNA genes combined with cloning and sequencing. Enrichment incubation demonstrated the microbial oxidation of crude oil coupled to methane production at 35 and 55°C, which generated 3.7±0.3 and 2.8±0.3 mmol of methane per gram oil, respectively. Gas chromatography-mass spectrometry (GC-MS analysis revealed that crude oil n-alkanes were obviously degraded, and high molecular weight n-alkanes were preferentially removed over relatively shorter-chain n-alkanes. Phylogenetic analysis revealed the concurrence of acetoclastic Methanosaeta and hydrogenotrophic methanogens but different methanogenic community structures under the two temperature conditions. Candidate divisions of JS1 and WWE 1, Proteobacteria (mainly consisting of Syntrophaceae, Desulfobacteraceae and Syntrophorhabdus and Firmicutes (mainly consisting of Desulfotomaculum were supposed to be involved with n-alkane degradation in the mesophilic conditions. By contrast, the different bacterial phylotypes affiliated with Caldisericales, "Shengli Cluster" and Synergistetes dominated the thermophilic consortium, which was most likely to be associated with thermophilic crude oil degradation. This study revealed that the oily sludge in Shengli oilfield harbors diverse uncultured microbes with great potential in methanogenic crude oil degradation over a wide temperature range, which extend our previous understanding of methanogenic degradation of crude oil alkanes.

  10. Investigation of relationships between removals of tetracycline and degradation products and physicochemical parameters in municipal wastewater treatment plant.

    Science.gov (United States)

    Topal, Murat; Uslu Şenel, Gülşad; Öbek, Erdal; Arslan Topal, E Işıl

    2016-05-15

    Determination of the effect of physicochemical parameters on the removal of tetracycline (TC) and degradation products is important because of the importance of the removal of antibiotics in Wastewater Treatment Plant (WWTP). Therefore, the purpose of this study was to investigate the relationships between removals of TC and degradation products and physicochemical parameters in Municipal Wastewater Treatment Plant (MWWTP). For this aim, (i) the removals of physicochemical parameters in a MWWTP located in Elazığ city (Turkey) were determined (ii) the removals of TC and degradation products in MWWTP were determined (iii) the relationships between removals of TC and degradation products and physicochemical parameters were investigated. TC, 4-epitetracycline (ETC), 4-epianhydrotetracycline (EATC), anhydrotetracycline (ATC), and physicochemical parameters (pH, temperature, electrical conductivity (EC), suspended solids (SS), BOD5, COD, total organic carbon (TOC), NH4(+)-N, NO2(-)-N, NO3(-)-N and O-PO4(-3)) were determined. The calculation of the correlation coefficients of relationships between the physicochemical parameters and TC, EATC, ATC showed that, among the investigated parameters, EATC and SS most correlated. The removals of other physicochemical parameters were not correlated with TC, EATC and ATC.

  11. A Novel Method for Assessing Drug Degradation Product Safety Using Physiologically-Based Pharmacokinetic Models and Stochastic Risk Assessment.

    Science.gov (United States)

    Nguyen, Hoa Q; Stamatis, Stephen D; Kirsch, Lee E

    2015-09-01

    Patient safety risk due to toxic degradation products is a potentially critical quality issue for a small group of useful drug substances. Although the pharmacokinetics of toxic drug degradation products may impact product safety, these data are frequently unavailable. The objective of this study is to incorporate the prediction capability of physiologically based pharmacokinetic (PBPK) models into a rational drug degradation product risk assessment procedure using a series of model drug degradants (substituted anilines). The PBPK models were parameterized using a combination of experimental and literature data and computational methods. The impact of model parameter uncertainty was incorporated into stochastic risk assessment procedure for estimating human safe exposure levels based on the novel use of a statistical metric called "PROB" for comparing probability that a human toxicity-target tissue exposure exceeds the rat exposure level at a critical no-observed-adverse-effect level. When compared with traditional risk assessment calculations, this novel PBPK approach appeared to provide a rational basis for drug instability risk assessment by focusing on target tissue exposure and leveraging physiological, biochemical, biophysical knowledge of compounds and species.

  12. Counteraction of antibiotic production and degradation stabilizes microbial communities

    OpenAIRE

    Kelsic, Eric D.; Zhao, Jeffrey; Vetsigian, Kalin; Kishony, Roy

    2015-01-01

    Summary A major challenge in theoretical ecology is understanding how natural microbial communities support species diversity 1-8 , and in particular how antibiotic producing, sensitive and resistant species coexist 9-15 . While cyclic “rock-paper-scissors” interactions can stabilize communities in spatial environments 9-11 , coexistence in unstructured environments remains an enigma 12,16 . Here, using simulations and analytical models, we show that the opposing actions of antibiotic product...

  13. Analysis of neem oils by LC-MS and degradation kinetics of azadirachtin-A in a controlled environment. Characterization of degradation products by HPLC-MS-MS.

    Science.gov (United States)

    Barrek, Sami; Paisse, Olivier; Grenier-Loustalot, Marie-Florence

    2004-02-01

    Since it was first isolated, the oil extracted from seeds of neem (Azadirachtin indica A juss) has been extensively studied in terms of its efficacy as an insecticide. Several industrial formulations are produced as emulsifiable solutions containing a stated titer of the active ingredient azadirachtin-A (AZ-A). The work reported here is the characterization of a formulation of this insecticide marketed under the name of Neem-azal T/S and kinetic studies of the major active ingredient of this formulation. We initially performed liquid-liquid extraction to isolate the neem oil from other ingredients in the commercial mixture. This was followed by a purification using flash chromatography and semi-preparative chromatography, leading to (13)C NMR identification of structures such as azadirachtin-A, azadirachtin-B, and azadirachtin-H. The neem extract was also characterized by HPLC-MS using two ionization sources, APCI (atmospheric pressure chemical ionization) and ESI (electrospray ionization) in positive and negative ion modes of detection. This led to the identification of other compounds present in the extract-azadirachtin-D, azadirachtin-I, deacetylnimbin, deacetylsalannin, nimbin, and salannin. The comparative study of data gathered by use of the two ionization sources is discussed and shows that the ESI source enables the largest number of structures to be identified. In a second part, kinetic changes in the main product (AZ-A) were studied under precise conditions of pH (2, 4, 6, and 8), temperature (40 to 70 degrees C), and light (UV, dark room and in daylight). This enabled us to determine the degradation kinetics of the product (AZ-A) over time. The activation energy of the molecule (75+/-9 kJ mol(-1)) was determined by examining thermal stability in the range 40 to 70 degrees C. The degradation products of this compound were identified by use of HPLC-MS and HPLC-MS-MS. The results enabled proposal of a chemical degradation reaction route for AZ-A under

  14. Stability behaviour of antiretroviral drugs and their combinations. 5: Characterization of novel degradation products of abacavir sulfate by mass and nuclear magnetic resonance spectrometry.

    Science.gov (United States)

    Kurmi, Moolchand; Sahu, Archana; Singh, Saranjit

    2017-02-05

    In the present study, degradation behaviour of abacavir sulfate was evaluated in solution and solid stress conditions. Solution state studies resulted in formation of eleven degradation products; of which two were also formed on solid stress. The same were separated by high performance liquid chromatography. They were characterized using liquid chromatography-high resolution mass spectrometry, liquid chromatography-multistage mass spectrometry and hydrogen/deuterium exchange mass spectrometry data. Additionally, seven degradation products were isolated and subjected to 1D and 2D nuclear magnetic resonance studies for their structural confirmation.

  15. Quantifying the impact of land degradation on crop production: the case of Senegal

    Science.gov (United States)

    Sonneveld, B. G. J. S.; Keyzer, M. A.; Ndiaye, D.

    2016-01-01

    Land degradation has been a persistent problem in Senegal for more than a century and by now has become a serious impediment to long-term development. In this paper, we quantify the impact of land degradation on crop yields using the results of a nationwide land degradation assessment. For this, the study needs to address two issues. First, the land degradation assessment comprises qualitative expert judgements that have to be converted into more objective, quantitative terms. We propose a land degradation index and assess its plausibility. Second, observational data on soils, land use, and rainfall do not provide sufficient information to isolate the impact of land degradation. We, therefore, design a pseudo-experiment that for sites with otherwise similar circumstances compares the yield of a site with and one without land degradation. This pairing exercise is conducted under a gradual refining of the classification of circumstances, until a more or less stable response to land degradation is obtained. In this way, we hope to have controlled sufficiently for confounding variables that will bias the estimation of the impact of land degradation on crop yields. A small number of shared characteristics reveal tendencies of "severe" land degradation levels being associated with declining yields as compared to similar sites with "low" degradation levels. However, as we zoom in at more detail some exceptions come to the fore, in particular in areas without fertilizer application. Yet, our overall conclusion is that yield reduction is associated with higher levels of land degradation, irrespective of whether fertilizer is being applied or not.

  16. Productive degradation of the biocide benzylbenzoate by Acinetobacter sp. strain AG1 isolated from the River Elbe.

    Science.gov (United States)

    Göttsching, Anja; Schmidt, Stefan

    2007-04-01

    From water sampled in the River Elbe, we isolated a bacterial strain able to use the biocidal compound benzylbenzoate as its sole source of carbon and energy under aerobic conditions. This isolate was tentatively assigned to the genus Acinetobacter due to its morphological, physiological and partial SSU rRNA gene sequence properties. The productive bacterial degradation of the biocide benzylbenzoate was demonstrated, and the catabolic sequence was elucidated biochemically. Growth experiments, along with enzymatic studies, demonstrated that strain Acinetobacter sp. AG1 hydrolyzed benzylbenzoate enzymatically to yield benzylalcohol and benzoate. Benzylalcohol was further transformed to benzoate via benzaldehyde. Benzoate was subsequently channeled via catechol into the oxoadipate pathway for further degradation.

  17. Mass spectrometry investigations on electrolyte degradation products for the development of nanocomposite electrodes in lithium ion batteries.

    Science.gov (United States)

    Gireaud, Laurent; Grugeon, Sylvie; Pilard, Serge; Guenot, Pierre; Tarascon, Jean-Marie; Laruelle, Stephane

    2006-06-01

    In the continuing challenge to find new routes to improve the performance of commercial lithium ion batteries cycling in alkyl carbonate-based electrolyte solutions, original designs, and new electrode materials are under active worldwide investigation. Our group has focused on the electrochemical behavior of a new generation of nanocomposite electrodes showing improved capacities (up to 3 times the capacity of conventional electrode materials). However, moving down to "nanometric-scale" active materials leads to a significant increase in electrolyte degradation, compared to that taking place within commercial batteries. Postmortem electrolyte studies on experimental coin cells were conducted to understand the degradation mechanisms. Structural analysis of the organic degradation products were investigated using a combination of complementary high-resolution mass spectrometry techniques: desorption under electron impact, electrospray ionization, and gas chromatography coupled to a mass spectrometer equipped with electron impact and chemical ionization ion sources. Numerous organic degradation products such as ethylene oxide oligomers (with methyl, hydroxyl, phosphate, and methyl carbonate endings) have been characterized. In light of our findings, possible chemical or electrochemical pathways are proposed to account for their formation. A thorough knowledge of these degradation mechanisms will enable us to propose new electrolyte formulations to optimize nanocomposite-based lithium ion battery performance.

  18. Role of nutrients and illuminance in predicting the fate of fungal mediated petroleum hydrocarbon degradation and biomass production.

    Science.gov (United States)

    Ali Khan, Aqib Hassan; Tanveer, Sundus; Anees, Mariam; Muhammad, Yousaf Shad; Iqbal, Mazhar; Yousaf, Sohail

    2016-07-01

    Biodegradation and biomass production are affected by numerous environmental factors including pH, oxygen availability and presence of pollutants. The present study, for the first time, elucidated the effects of nutrients and light on mycodegradation of petroleum hydrocarbons in diesel oil. Seven fungal strains (Aspergillus terreus FA3, Aspergillus niger FA5, Aspergillus terreus FA6, Penicillium chrysogenum FP4, Aspergillus terreus FP6, Aspergillus flavus FP10, and Candida sp. FG1) were used for hydrocarbon degradation under static conditions, in four combinations of nutrient media and illuminance for 45 days. Highest degradation was achieved by Aspergillus terreus FA6 and Candida sp. FG1 under both conditions of light and dark, with nutrient deprived HAF (Hydrocarbon adopted fungi) broth. Under HAF/Dark diesel oil degradation by FA6 and FG1 was 87.3% and 84.3% respectively, while under HAF/Light both FA6 and FG1 performed 84.3% biodegradation. The highest biomass was produced by Aspergillus flavus FP10 in PDB (Potato dextrose broth)/Dark (109.3 mg). Fungal degradation of petroleum hydrocarbons was negatively affected by the presence of other simpler-to-degrade carbon sources in the medium. The biomass production was enhanced by improved nutrient availability and diminished by illuminance.

  19. Fe-Mn alloys for metallic biodegradable stents: degradation and cell viability studies.

    Science.gov (United States)

    Hermawan, Hendra; Purnama, Agung; Dube, Dominique; Couet, Jacques; Mantovani, Diego

    2010-05-01

    Biodegradable stents have shown their potential to be a valid alternative for the treatment of coronary artery occlusion. This new class of stents requires materials having excellent mechanical properties and controllable degradation behaviour without inducing toxicological problems. The properties of the currently considered gold standard material for stents, stainless steel 316L, were approached by new Fe-Mn alloys. The degradation characteristics of these Fe-Mn alloys were investigated including in vitro cell viability. A specific test bench was used to investigate the degradation in flow conditions simulating those of coronary artery. A water-soluble tetrazolium test method was used to study the effect of the alloy's degradation product to the viability of fibroblast cells. These tests have revealed the corrosion mechanism of the alloys. The degradation products consist of metal hydroxides and calcium/phosphorus layers. The alloys have shown low inhibition to fibroblast cells' metabolic activities. It is concluded that they demonstrate their potential to be developed as degradable metallic biomaterials.

  20. Effects of chemical compositions and ensiling on the biogas productivity and degradation rates of agricultural and food processing by-products.

    Science.gov (United States)

    Kafle, Gopi Krishna; Kim, Sang Hun

    2013-08-01

    The objective of this study was to investigate the effects of chemical compositions and ensiling on the biogas productivity and degradation rates of agricultural and food processing by-products (AFPBPs) using the biogas potential test. The AFPBPs were classified based on their chemical compositions (i.e., carbohydrate, protein and fat contents). The biogas and methane potentials of AFPBPs were calculated to range from 450 to 777 mL/g volatile solids (VS) and 260-543 mL/g VS, respectively. AFPBPs with high fat and protein contents produced significantly higher amounts of biogas than AFPBPs with high carbohydrate and low fat contents. The degradation rate was faster for AFPBPs with high carbohydrate contents compared to AFPBPs with high protein and fat contents. The lag phase and biogas production duration were lower when using ensiled AFPBPs than when using nonsilage AFPBPs. Among the four different silages tested, two silages significantly improved biogas production compared to the nonsilage AFPBPs.

  1. NMR Studies of Cartilage Dynamics, Diffusion, Degradation

    Science.gov (United States)

    Huster, Daniel; Schiller, Jurgen; Naji, Lama; Kaufmann Jorn; Arnold, Klaus

    An increasing number of people is suffering from rheumatic diseases, and, therefore, methods of early diagnosis of joint degeneration are urgently required. For their establishment, however, an improved knowledge about the molecular organisation of cartilage would be helpful. Cartilage consists of three main components: Water, collagen and chondroitin sulfate (CS) that is (together with further polysaccharides and proteins) a major constituent of the proteoglycans of cartilage. 1H and 13C MAS (magic-angle spinning) NMR (nuclear magnetic resonance) opened new perspectives for the study of the macromolecular components in cartilage. We have primarily studied the mobilities of CS and collagen in bovine nasal and pig articular cartilage (that differ significantly in their collagen/polysaccharide content) by measuring 13C NMR relaxation times as well as the corresponding 13C CP (cross polarisation) MAS NMR spectra. These data clearly indicate that the mobility of cartilage macromolecules is broadly distributed from almost completely rigid (collagen) to highly mobile (polysaccharides), which lends cartilage its mechanical strength and shock-absorbing properties.

  2. Degradation of organic compounds and production of activated species in Dielectric Barrier Discharges and Glidarc reactors

    CERN Document Server

    Cormier, Jean Marie; Khacef, Ahmed

    2008-01-01

    Major sterilization mechanisms are related to atoms and radicals, charged parti-cles, excited molecules, ozone, and UV radiation. The ROS (Reactive Oxygen Species) are well known as evildoers. These species are easily created in ambient air and water and they live long enough to reach the cell and attack the organic matter. Test molecules conversion in dry and wet air is studied using Dielectric Barrier Discharge (DBD) and Gliding Arc Reactors (GAR). The effects of tem-perature and energy deposition into the media on the active species production and then on the organic compounds degradation are presented for two non thermal plasma reactors: DBD and GAR. Main production species investigated are OH, O3, NOx, CO and CxHyOz by-products. It is shown from experiment analysis that the reactive species production is quite different from one reactor to another. GAR and pulsed DBD are two chemical processing ways in which the temperature of heavy species in ionized gas is determinant. By reviewing the species producti...

  3. Precipitation of organic arsenic compounds and their degradation products during struvite formation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jin-Biao; Yuan, Shoujun [School of Civil Engineering, Hefei University of Technology, Hefei 230009 (China); Institute of Water Treatment and Wastes Reutilization, Hefei University of Technology, Hefei 230009 (China); Wang, Wei, E-mail: dwhit@126.com [School of Civil Engineering, Hefei University of Technology, Hefei 230009 (China); Institute of Water Treatment and Wastes Reutilization, Hefei University of Technology, Hefei 230009 (China); Hu, Zhen-Hu, E-mail: zhhu@hfut.edu.cn [School of Civil Engineering, Hefei University of Technology, Hefei 230009 (China); Institute of Water Treatment and Wastes Reutilization, Hefei University of Technology, Hefei 230009 (China); Yu, Han-Qing [Department of Chemistry, University of Science & Technology of China, Hefei 230026 (China)

    2016-11-05

    Highlights: • Organic and inorganic arsenic compounds precipitated during struvite formation. • Precipitation of organic arsenic compounds in struvite decreased with increasing pH. • Arsenate easily precipitate in struvite as compared to organic arsenic compounds. • Arsenic compounds in solution affected the shape of struvite crystallization products. - Abstract: Roxarsone (ROX) and arsanilic acid (ASA) have been extensively used as organoarsenic animal feed additives. Organic arsenic compounds and their degradation products, arsenate (As(V)) and arsenite (As(III)), exist in the effluent from anaerobic reactors treating animal manure contaminated by ROX or ASA with ammonium (NH{sub 4}{sup +}-N) and phosphate (PO{sub 4}{sup 3−}-P) together. Therefore, arsenic species in the effluent might be involved in the struvite formation process. In this study, the involvement of organic arsenic compounds and their degradation products As(V) and As(III) in the struvite crystallization was investigated. The results demonstrated that arsenic compounds did not substantially affect the PO{sub 4}{sup 3−}-P recovery, but confirmed the precipitation of arsenic during struvite formation. The precipitation of arsenic compounds in struvite was considerably affected by a solution pH from 9.0 to 11.0. With an increase in pH, the content of ASA and ROX in the precipitation decreased, but the contents of As(III) and As(V) increased. In addition, the arsenic content of As(V) in the struvite was higher than that of As(III), ASA and ROX. The results indicated that the struvite could be contaminated when the solution contains arsenic species, but that could be minimized by controlling the solution pH and maintaining anaerobic conditions during struvite formation.

  4. Recognizing Potential Buprenorphine Medication Misuse: Product Packaging Does Not Degrade With Laundering.

    Science.gov (United States)

    Gunderson, Erik W

    2015-01-01

    Expanded office-based buprenorphine opioid dependence treatment is associated with medication misuse and diversion consequences. Recurrent early refill requests may indicate misuse or diversion, although further research is needed on how to effectively recognize and address the issue in clinical practice. In the current study, patient report of damaged medication from laundering prompted evaluation of laundering on degradation of buprenorphine-containing product packages and contents. Four buprenorphine product packaging approaches were assessed: 3 buprenorphine/naloxone placebo demonstration products (Suboxone and Bunavail film in foil wrappers and Zubsolv tablet in a blister pack) and Rexam-manufactured Screw-Loc closure pill container filled with a chewable aspirin as a surrogate for generic buprenorphine and buprenorphine/naloxone products. Two experimental laundering conditions, wash machine alone (W) and washer/dryer (W+D), were compared with unlaundered control (C) condition. Standard laundering settings were based on patient presentation. Products from the 2 experimental conditions and the control condition were labeled A, B, or C with counterbalanced assignment prior to visual examination of packaging and contents by the investigator who was blinded to condition. Packaging and contents remained intact for all products across experimental conditions, with only minor cosmetic effects compared with control. The W+D Suboxone film had 1-2 mm curling of the wrapper corners. Zubsolv blister packs had slight paper label fading (W+D > W). Bunavail W+D foil had an indentation outlining the inner film. The W+D bottle tablet had a ˜1 mm nick on one edge. No other differences were noted. After implementing more structured treatment and reviewing the results with the patient, he endorsed fabricating the laundering story to get additional medication. Laundering is an unlikely cause of damaged buprenorphine-containing medication packaged in foil wrappers (Suboxone

  5. Study of OH-initiated degradation of 2-aminoethanol

    Directory of Open Access Journals (Sweden)

    M. Karl

    2011-10-01

    Full Text Available The degradation of 2-aminoethanol (MEA by the hydroxyl radical (OH was studied in the European Photoreactor (EUPHORE, a large outdoor environmental chamber. High-Temperature Proton-Transfer-Reaction Mass Spectrometry (HT-PTR-MS and Fast Fourier Transform Infrared (FT-IR were used to follow concentrations of reactants in the gas phase. Aerosol mass concentrations were tracked with Aerosol Mass Spectrometry (AMS. The chamber aerosol model MAFOR was applied to quantify losses of MEA to the particle phase. The rate constant k(OH+MEA was determined relative to the rate constant of the 1,3,5-trimethylbenzene reaction with OH and was found to be (9.2 ± 1.1×10−11 cm3 molecule−1 s−1, and thus the reaction between OH radicals and MEA proceeds a factor of 2–3 faster than estimated by structure-activity relationship (SAR methods. Main uncertainty of the relative rate determination is the unknown temporal behaviour of the loss rate of MEA to chamber wall surfaces during the sunlit experiments. Nucleation and growth of particles observed in the experiments could be reproduced by the chamber model that accounted for condensation of gaseous oxidation products, condensation of ethanolaminium nitrate and nucleation involving MEA and nitric acid.

  6. New insights into atrazine degradation by cobalt catalyzed peroxymonosulfate oxidation: kinetics, reaction products and transformation mechanisms.

    Science.gov (United States)

    Ji, Yuefei; Dong, Changxun; Kong, Deyang; Lu, Junhe

    2015-03-21

    The widespread occurrence of atrazine in waters poses potential risk to ecosystem and human health. In this study, we investigated the underlying mechanisms and transformation pathways of atrazine degradation by cobalt catalyzed peroxymonosulfate (Co(II)/PMS). Co(II)/PMS was found to be more efficient for ATZ elimination in aqueous solution than Fe(II)/PMS process. ATZ oxidation by Co(II)/PMS followed pseudo-first-order kinetics, and the reaction rate constant (k(obs)) increased appreciably with increasing Co(II) concentration. Increasing initial PMS concentration favored the decomposition of ATZ, however, no linear relationship between k(obs) and PMS concentration was observed. Higher efficiency of ATZ oxidation was observed around neutral pH, implying the possibility of applying Co(II)/PMS process under environmental realistic conditions. Natural organic matter (NOM), chloride (Cl(-)) and bicarbonate (HCO3(-)) showed detrimental effects on ATZ degradation, particularly at higher concentrations. Eleven products were identified by applying solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC/MS) techniques. Major transformation pathways of ATZ included dealkylation, dechlorination-hydroxylation, and alkyl chain oxidation. Detailed mechanisms responsible for these transformation pathways were discussed. Our results reveal that Co(II)/PMS process might be an efficient technique for remediation of groundwater contaminated by ATZ and structurally related s-triazine herbicides.

  7. Enhanced biofilm production by a toluene-degrading Rhodococcus observed after exposure to perfluoroalkyl acids.

    Science.gov (United States)

    Weathers, Tess S; Higgins, Christopher P; Sharp, Jonathan O

    2015-05-05

    This study focuses on interactions between aerobic soil-derived hydrocarbon degrading bacteria and a suite of perfluorocarboxylic acids and perfluoroalkylsulfonates that are found in aqueous film-forming foams used for fire suppression. No effect on toluene degradation rate or induction time was observed when active cells of Rhodococcus jostii strain RHA1 were exposed to toluene and a mixture of perfluoroalkyl acids (PFAAs) including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) at concentrations near the upper bounds of groundwater relevance (11 PFAAs at 10 mg/L each). However, exposure to aqueous PFAA concentrations above 2 mg/L (each) was associated with enhanced aggregation of bacterial cells and significant increases in extracellular polymeric substance production. Flocculation was only observed during exponential growth and not elicited when PFAAs were added to resting incubations; analogous flocculation was also observed in soil enrichments. Aggregation was accompanied by 2- to 3-fold upregulation of stress-associated genes, sigF3 and prmA, during growth of this Rhodococcus in the presence of PFAAs. These results suggest that biological responses, such as microbial stress and biofilm formation, could be more prominent than suppression of co-contaminant biodegradation in subsurface locations where poly- and perfluoroalkyl substances occur with hydrocarbon fuels.

  8. Assessing Forest Plantation Productivity of Exotic and Indigenous Species on Degraded Secondary Forests

    Directory of Open Access Journals (Sweden)

    Yetti Heryati

    2011-01-01

    Full Text Available Problem statement: There is general agreement that human activities such as deforestation and land use change to other land use types have contributed to degraded secondary forests or forestland and increases the emission of greenhouse gases which ultimately led to global climate change. An establishment of forest plantation in particular is regarded as an important approach for sequestering carbon. However, limited information exists on productivity and potential of fast growth exotic and indigenous tree plantations for sequestering CO2 from the atmosphere through photosynthesis. This study aimed at assessing the productivity and biomass accumulation along with the potential for sequestering CO2 of planted exotic and indigenous species on degraded forestland. Approach: This study was conducted at Khaya ivorensis and Hopea odorata plantations, which was planted at the Forest Research Institute Malaysia (FRIM Research Station in Segamat Johor, Malaysia five years ago. In order, to evaluate the forest productivity and biomass accumulation of both species, we established plots with a size of 40 × 30 m in three replications in each stand, followed by measuring all trees in the plots in terms of height and Diameter at Breast Height (DBH. To develop allometric equation, five representative trees at each stand were chosen for destructive sampling. Results: The growth performance in terms of mean height, DBH, annual increment of height and diameter and basal area of exotic species (K. ivorensis was significantly higher than that of the indigenous species (H. odorata. We used the diameter alone as independent variable to estimate stem volume and biomass production of both species. The stem volume of K. ivorensis stand was 43.13 m3ha-1 and was significantly higher than H. odorata stands (33.66 m3 ha-1. The results also showed that the K. ivorensis and H. odorata stands have the potential to absorb CO2 from the atmosphere which was stored in aboveground

  9. Experimental and theoretical studies on the OH-initiated degradation of tert-butylamine

    Science.gov (United States)

    Tan, Wen; D'Anna, Barbara; Eichler, Philipp; Mikoviny, Tomas; Müller, Markus; Jørgen Nielsen, Claus; Wisthaler, Armin; Zhu, Liang

    2017-04-01

    Amine-based carbon dioxide (CO2) capture facilities release small amounts of amines into the atmosphere. Once airborne, the amines are photochemically transformed into imines, amides, nitrosamines, nitramines and other breakdown products. As some of these products pose a risk to human health and the environment, we have elucidated photochemical decomposition mechanisms of various types of amines in previous work. Our studies did, however, not include amines in which the primary amino group is attached to a tertiary carbon atom, with 2-amino-2-methyl-1-propanol (AMP, (CH3)2C(NH2)CH2OH) being a prominent candidate used in CO2 capture. Our initial step in elucidating the degradation mechanism of AMP was to study tert-butylamine (tBA, (CH3)3C(NH2)), which is a similar molecule but lacks the OH group. OH-initiated degradation of tBA was studied in chamber experiments at the European Photoreactor (EUPHORE) in Valencia (Spain) using state-of-the-art analytical instrumentation. A Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) was used to measure tBA and tBA degradation products in the gas phase. Propan-2-imine (PI, (CH3)2C(=NH)) and tert-butylnitramine (tBNA, (CH3)3C(NHNO2)) were observed as the two major gas-phase products. An Aerosol Mass Spectrometer (AMS) made quantitative measurements of tert-butylaminium nitrate in the particle phase. A PTR-ToF-MS instrument equipped with a "chemical analysis of aerosol online" (CHARON) inlet detected the two major tBA degradation products (PI, tBNA) in the particle phase. Experimental work was supplemented by quantum chemistry calculations. We will present measured product yields and a complete degradation scheme of tBA. This work was supported by the Norwegian Research Council CLIMIT program under contract 244055.

  10. Leaching of azoxystrobin and its degradation product R234886 from Danish agricultural field sites

    DEFF Research Database (Denmark)

    Jørgensen, Lisbeth Flindt; Kjær, Jeanne; Olsen, Preben

    2012-01-01

    harmful. Our study shows that azoxystrobin and R234886 can leach through loamy soils for a long period of time following application of the pesticide and thereby pose a potential threat to vulnerable aquatic environments and drinking water resources. We thus recommend the inclusion of azoxystrobin and R......The objective was to estimate leaching of the fungicide azoxystrobin (methyl (αE)-2-[[6-(2-cyanophenoxy)-4-pyrimidinyl]oxy]-α-(methoxymethylene)benzene-acetate) and one of its primary degradation products R234886 ([(E)-2-(2-[6-cyanophenoxy)-pyrimidin-4-yloxyl]-phenyl-3-methoxyacrylic acid], major...... through loamy soils. While azoxystrobin was generally only detected during the first couple of months following application, R234886 leached for a longer period of time and at higher concentrations (up to 2.1 μg L−1). Azoxystrobin is classified as very toxic to aquatic organisms and R234886 as very...

  11. Time evolution and competing pathways in photodegradation of trifluralin and three of its major degradation products.

    Science.gov (United States)

    Tagle, Martín G Sarmiento; Laura Salum, María; Buján, Elba I; Argüello, Gustavo A

    2005-11-01

    The herbicide trifluralin (I)(N,N-di-n-propyl-2,6-dinitro-4-trifluoromethylaniline) decomposes, by the action of UV-Vis light (lambda > 300 nm), to several products, the most important (because they give subsequent photochemical reactions) being N-n-propyl-2,6-dinitro-4-trifluoromethylaniline (VI), 2-ethyl-7-nitro-5-trifluoromethyl-1H-benzimidazole 3-oxide (VII) and 2,6-dinitro-4-trifluoromethylaniline (XII). The time evolution of degradation of trifluralin (I) and the aforementioned three main photoproducts was studied in water and acetonitrile as solvents. The pseudo-first order rate constants allow one to calculate the branching ratios for some of the reactions involved. The preference for either N-dealkylation or cyclization depends on the solvent employed. Dissolved oxygen accelerates the photodegradation, especially the dealkylation.

  12. Detection of some volatile degradation products released during photoexposition of ranitidine in a solid state.

    Science.gov (United States)

    Jamrógiewicz, Marzena; Wielgomas, Bartosz

    2013-03-25

    Ranitidine (RAN) is on top of the list of prescribed drugs, due to its popularity as a selective H2-receptor antagonist, which efficiently decreases the amount of acid produced in the stomach. RAN is not stable both in a solid state and in a solution, which creates manufacturing problems, requires appropriate storage conditions, and results in a short drug shelf-life. The aim of this work was to study the emission of volatile degradation products generated during photoexposition of ranitidine hydrochloride in a solid state. Significant changes in volatile profile of irradiated RAN were detected using HS-SPME-GC-MS. Sixteen major peaks were noticed on the chromatograms of irradiated ranitidine and the structures of some compounds were elucidated, while the presence of acetaldoxime, thiazole, dimethylformamide, dimethylacetamide and 5-methylfurfural was confirmed by means of the analysis of the authentic standards.

  13. Peritoneal dialysis solutions low in glucose degradation products: clinical experience and outcomes.

    Science.gov (United States)

    Diaz-Buxo, Jose A

    2007-01-01

    The latest literature describing clinical experiences with peritoneal dialysis solutions low in glucose degradation products (GDPs) is mostly consistent with previous reports suggesting less inflammation, better peritoneal mesothelial mass preservation, a lower rate of decline of residual renal function, and improved patient survival. The data suggest stable peritoneal transport rates, but no definite evidence has yet emerged of superior membrane preservation. Most studies have reported very low peritonitis rates, but without significant differences as compared with rates in patients exposed to conventional solutions. New, appropriately powered randomized clinical trials are needed to confirm the potential benefits of low-GDP solutions and to establish the role of renal function preservation with regard to those benefits.

  14. Characterization of forced degradation products and in silico toxicity prediction of Sofosbuvir: A novel HCV NS5B polymerase inhibitor.

    Science.gov (United States)

    Swain, Debasish; Samanthula, Gananadhamu; Bhagat, Shweta; Bharatam, P V; Akula, Venkatakrishna; Sinha, Barij N

    2016-02-20

    Sofosbuvir is a direct acting antiviral medication used to treat Hepatitis C viral infection. The present study focuses on the degradation behavior of the drug under various stress conditions (hydrolysis, oxidative, thermal and photolytic) as per International Conference on Harmonization (ICH Q1A (R2)) guidelines. A high performance liquid chromatographic system (HPLC) was used to develop a selective, precise and accurate method for separating all the degradation products. The separation was achieved on a Sunfire™ C18 (150mm×4.6mm×5μm) stationary phase with a mobile phase of 10mM ammonium acetate (pH 5.0) buffer and acetonitrile in gradient elution mode. A quadrupole-time of flight mass analyzer equipped with an electrospray ionization technique was used to propose the structural information based on the MS/MS and accurate mass measurements. Seven degradation products were identified and characterised by LC-ESI-QTOF-MS/MS. In silico toxicity of the drug and its degradation products was determined using TOPKAT and DEREK toxicity prediction softwares. The proposed method was validated as per the ICH Q2 guidelines.

  15. Stability-Indicating RP-HPLC Method for Simultaneous Estimation of Enrofloxacin and Its Degradation Products in Tablet Dosage Forms

    Directory of Open Access Journals (Sweden)

    V. Ashok Chakravarthy

    2015-01-01

    Full Text Available The present work was the development of a simple, efficient, and reproducible stability-indicating reverse-phase high performance liquid chromatographic (RP-HPLC method for simultaneous determination enrofloxacin (EFX and its degradation products including ethylenediamine impurity, desfluoro impurity, ciprofloxacin impurity, chloro impurity, fluoroquinolonic acid impurity, and decarboxylated impurity in tablet dosage forms. The separation of EFX and its degradation products in tablets was carried out on Kromasil C-18 (250×4.6 mm, 5 μm column using 0.1% (v/v TEA in 10 mM KH2PO4 (pH 2.5 buffer and methanol by linear gradient program. Flow rate was 1.0 mL min−1 with a column temperature of 35°C and detection wavelength was carried out at 278 nm and 254 nm. The forced degradation studies were performed on EFX tablets under acidic, basic, oxidation, thermal, humidity, and photolytic conditions. The degraded products were well resolved from the main active drug and also from known impurities within 65 minutes. The method was validated in terms of specificity, linearity, LOD, LOQ, accuracy, precision, and robustness as per ICH guidelines. The results obtained from the validation experiments prove that the developed method is a stability-indicating method and suitable for routine analysis.

  16. Stability-Indicating Method and LC-MS-MS Characterization of Forced Degradation Products of Sofosbuvir.

    Science.gov (United States)

    Nebsen, M; Elzanfaly, Eman S

    2016-07-19

    Sofosbuvir is a novel direct acting antiviral agent against hepatitis C virus. In the present work, a rapid, specific and reproducible isocratic reversed phase high performance liquid chromatography (RP-HPLC) method has been developed and validated for the determination of sofosbuvir in the presence of its stressed degradation products. Sobosbuvir was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per international conference on harmonization (ICH) conditions. The drug showed degradation under oxidative, photolysis, acid and base hydrolysis stress conditions. However, it was stable under thermal and neutral hydrolysis stress conditions. Chromatographic separation of the drug from its degradation products was performed on Inertsil ODS-3 C18 (250 mm × 4.6 mm i.d., 5 µm) column using a green mobile phase of methanol:water 70:30 (v/v). The degradation products were characterized by LC-MS-MS and the fragmentation pathways were proposed. The developed method was validated as per ICH guidelines. No previous method was reported regarding the degradation behavior of sofosbuvir.

  17. Progress and obstacles in the production and application of recombinant lignin-degrading peroxidases.

    Science.gov (United States)

    Lambertz, Camilla; Ece, Selin; Fischer, Rainer; Commandeur, Ulrich

    2016-04-01

    Lignin is 1 of the 3 major components of lignocellulose. Its polymeric structure includes aromatic subunits that can be converted into high-value-added products, but this potential cannot yet been fully exploited because lignin is highly recalcitrant to degradation. Different approaches for the depolymerization of lignin have been tested, including pyrolysis, chemical oxidation, and hydrolysis under supercritical conditions. An additional strategy is the use of lignin-degrading enzymes, which imitates the natural degradation process. A versatile set of enzymes for lignin degradation has been identified, and research has focused on the production of recombinant enzymes in sufficient amounts to characterize their structure and reaction mechanisms. Enzymes have been analyzed individually and in combinations using artificial substrates, lignin model compounds, lignin and lignocellulose. Here we consider progress in the production of recombinant lignin-degrading peroxidases, the advantages and disadvantages of different expression hosts, and obstacles that must be overcome before such enzymes can be characterized and used for the industrial processing of lignin.

  18. New insight into monitoring degradation products during the TiO2-photocatalysis process by multivariate molecular spectroscopy.

    Science.gov (United States)

    Stets, Sandra; do Amaral, Bianca; Bach, Larissa; Nagata, Noemi; Peralta-Zamora, Patricio G

    2017-03-01

    This study focuses on the feasibility of a spectroscopic multivariate method for monitoring the concentration of phenol and its main degradation products during heterogeneous photocatalysis. Phenolic compounds were chosen as model to evaluate the degradation process due to their toxicity and persistence in the environment and also their well-known degradation pathway. The predictive capability of the multivariate method developed by partial least squares regression (PLSR) over the spectral range of 200-350 nm was satisfactory, allowing mean predicted errors below 5.0 % in the simultaneous determination of the target compounds using six latent variables and smoothing spectra. Suitable results were reported for the simultaneous determination of hydroquinone, resorcinol, pyrocatechol, and p-benzoquinone in accordance to the chromatographic method. Characteristics such as simplicity, low cost, and fast data acquisition are remarkable in this procedure, which makes it appropriate for this type of analytical control.

  19. Occurrence of pesticides and some of their degradation products in waters in a Spanish wine region

    Science.gov (United States)

    Herrero-Hernández, E.; Andrades, M. S.; Álvarez-Martín, A.; Pose-Juan, E.; Rodríguez-Cruz, M. S.; Sánchez-Martín, M. J.

    2013-04-01

    SummaryA multi-residual analytical method based on solid phase extraction (SPE) followed by liquid chromatography-electrospray ionisation-mass spectrometry (LC-MS) was developed to monitor pesticides in natural waters. Fifty-eight compounds, including herbicides, fungicides, insecticides and some of their degradation products, were surveyed to evaluate the quality of natural waters throughout the wine-growing region of La Rioja (Rioja DOCa). Ninety-two sampling points were selected, including surface and ground waters that could be affected by agricultural activities covering the region's three sub-areas. Different parameters that may affect the efficiency of the SPE procedure were optimised (sorbent type, elution solvent and sample volume), and matrix-matched standards were used to eliminate the variable matrix effect and ensure good quantification. The developed method allows the determination of target compounds below the level established by the European Union for waters for human use with suitable precision (relative standard deviations lower than 18%) and accuracy (with recoveries over 61%). Forty compounds included in this study (six insecticides, 12 herbicides, 16 fungicides and six degradation products) were detected in one or more samples. The herbicides terbuthylazine, its metabolite desethyl terbuthylazine, fluometuron and ethofumesate and the fungicides pyrimethanil and tebuconazole were the compounds most frequently detected in water samples (present in more than 60% of the samples). Concentrations above 0.1 μg L-1 were detected for 37 of the compounds studied, and in several cases recorded values of over 18 μg L-1. The results reveal the presence of pesticides in most of the samples investigated. In 64% of groundwaters and 62% of surface waters, the sum of compounds detected was higher than 0.5 μg L-1 (the limit established by EU legislation for the sum of all pesticides detected in waters for human use).

  20. organochlorine pesticides and degradation products in soil around a ...

    African Journals Online (AJOL)

    dell

    1995, ATSDR 2002,. 2005). The objective of this study was to investigate the levels and compositions of organochlorine ... roll papers, polyethylene bags, waste plastic bags and ... filter placed on top. ..... WX, Li BG, Shen WR, Zhang WJ, Qin.

  1. Occurrence and Antioxidant Activity of C1 Degradation Products in Cocoa

    Science.gov (United States)

    De Taeye, Cédric; Kankolongo Cibaka, Marie-Lucie; Collin, Sonia

    2017-01-01

    Procyanidin C1 is by far the main flavan-3-ol trimer in cocoa. Like other flavan-3-ols, however, it suffers a lot during heat treatments such as roasting. RP-HPLC-HRMS/MS(ESI(−))analysis applied to an aqueous model medium containing commercial procyanidin C1 proved that epimerization is the main reaction involved in its degradation (accounting for 62% of degradation products). In addition to depolymerization, cocoa procyanidin C1 also proved sensitive to oxidation, yielding once- and twice-oxidized dimers. No chemical oligomer involving the native trimer was found in either model medium or cocoa, while two C1 isomers were retrieved. C1 degradation products exhibited antioxidant activity (monitored by RP-HPLC-Online TEAC) close to that of C1 (when expressed in µM TE/mg·kg−1). PMID:28264525

  2. In vitro quantitative study of the degradation of endomorphins.

    Science.gov (United States)

    Tömböly, Csaba; Péter, Antal; Tóth, Géza

    2002-09-01

    The catabolism of the endomorphins was investigated in detail. The endomorphins were degraded relatively slowly in the rat brain homogenate (t1/2(endomorphin-1)=4.94 min; t1/2(endomorphin-2)=3.81 min). The inhibition of metalloproteases and aminopeptidases stabilised the endomorphins to the greatest extent. The digestion of endomorphins tritiated specifically on Tyr(1), Pro(2) or Phe(3) established also that only the aminopeptidase pathways were essential for inactivation of the endomorphins, and that the tetrapeptides were degraded by cleavage of the Pro(2)-Trp(3) or Pro(2)-Phe(3) bond. The end-products of the catabolism were amino acids; the fragments Tyr-Pro-OH and Pro-Trp-Phe-NH2 were present as intermediates. Metabolites produced by brain carboxypeptidases were not detected.

  3. A Structure Identification and Toxicity Assessment of the Degradation Products of Aflatoxin B1 in Peanut Oil under UV Irradiation

    Science.gov (United States)

    Mao, Jin; He, Bing; Zhang, Liangxiao; Li, Peiwu; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen

    2016-01-01

    Aflatoxins, a group of extremely hazardous compounds because of their genotoxicity and carcinogenicity to human and animals, are commonly found in many tropical and subtropical regions. Ultraviolet (UV) irradiation is proven to be an effective method to reduce or detoxify aflatoxins. However, the degradation products of aflatoxins under UV irradiation and their safety or toxicity have not been clear in practical production such as edible oil industry. In this study, the degradation products of aflatoxin B1 (AFB1) in peanut oil were analyzed by Ultra Performance Liquid Chromatograph-Thermo Quadrupole Exactive Focus mass spectrometry/mass spectrometry (UPLC-TQEF-MS/MS). The high-resolution mass spectra reflected that two main products were formed after the modification of a double bond in the terminal furan ring and the fracture of the lactone ring, while the small molecules especially nitrogen-containing compound may have participated in the photochemical reaction. According to the above results, the possible photodegradation pathway of AFB1 in peanut oil is proposed. Moreover, the human embryo hepatocytes viability assay indicated that the cell toxicity of degradation products after UV irradiation was much lower than that of AFB1, which could be attributed to the breakage of toxicological sites. These findings can provide new information for metabolic pathways and the hazard assessment of AFB1 using UV detoxification. PMID:27845743

  4. The potential of intercropping food crops and energy crop to improve productivity of a degraded agriculture land in arid tropics

    Directory of Open Access Journals (Sweden)

    I.K.D. Jaya

    2014-04-01

    Full Text Available Degraded agricultural lands in the arid tropics have low soil organic carbon (SOC and hence low productivity. Poor farmers that their livelihoods depend highly on these types of lands are suffering. Cropping strategies that are able to improve the soil productivity are needed. In the present study, some intercropping models of food crops with bio-energy crop of castor (Ricinus communis L. were tested to assess their potential to improve the degraded land productivity. The intercropping models were: (1 castor - hybrid maize, (2 castor – short season maize, (3 castor – mungbean, and (4 castor –short season maize – mungbean. The results show that yields of the component crops in monoculture were relatively the same as in intercropping, resulted in a high Land Equivalent Ratio (LER. The highest LER (3.07 was calculated from intercropping castor plants with short season maize crops followed by mungbean with intercropping productivity of IDR 15,097,600.00 ha-1. Intercropping has a great potential to improve degraded agriculture land productivity and castor is a promising plant to improve biodiversity and area coverage on the land.

  5. Degradation of indomethacin in river water under stress and non-stress laboratory conditions: degradation products, long-term evolution and adsorption to sediment.

    Science.gov (United States)

    Jiménez, Juan J; Sánchez, María I; Pardo, Rafael; Muñoz, Beatriz E

    2017-01-01

    The pharmaceutical compound indomethacin is not totally removed in wastewater treatment plants, whose effluents flow into aquatic environments; concentrations in the 0.1-100ng/L range are commonly found in surface waters, and its fate is unknown. Here, biological, photochemical and thermal degradation assays were conducted under stress and non-stress conditions to estimate its degradation rate in river water and establish its degradation products over time. The results revealed that direct sunlight irradiation promoted the complete degradation of indomethacin (2μg/L) in less than 6hr, but indomethacin was detected over a period of 4months when water was kept under the natural day-night cycle and the exposure to sunlight was partially limited, as occurs inside a body of water. The biological degradation in water was negligible, while the hydrolysis at pH7.8 was slow. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction, and six degradation products were found; their structures were proposed based on the molecular formulae and fragmentation observed in high-resolution tandem mass spectra. 4-Chlorobenzoic and 2-acetamido-5-methoxybenzoic acids were the long-term transformation products, persisting for at least 30weeks in water kept under non-stress conditions. Furthermore, the degradation in the presence of sediment was also monitored over time, with some differences being noted. The adsorption coefficients of indomethacin and degradation products on river sediment were calculated; long-term degradation products did not have significant adsorption to sediment. Copyright © 2016. Published by Elsevier B.V.

  6. Optimized production of extracellular proteases by Bacillus subtilis from degraded abattoir waste

    Directory of Open Access Journals (Sweden)

    PALLAVI BADHE

    2016-04-01

    Full Text Available Proteases are ubiquitous in occurrence and are found in all living organisms. These are essential for cell growth and differentiation. The extracellular proteases are of a high commercial value and find multiple applications in various industrial sectors. The present study describes the screening of protease producing bacteria from a hitherto unexplored source i.e. degraded waste from abattoir. Three isolates were found namely yellow, white and orange coloured bacteria. Amongst them, white colored colony was found to be more suitable for protease production. The morphological, cultural, biochemical and 16S rRNA confirmed that the isolate was Bacillus subtilis. Physical and chemical parameters were optimized for maximum protease production and optimum temperature and pH was found to be 40oC at pH 14. Glucose as a carbon source and yeast extract as a nitrogen source further stimulated the production process giving maximum protease activity to be 20.74 U/ml and 20.67 U/ml. The applications of protease in detergent and solvent industry were tested and it was revealed that the purified enzyme can be used as an additive in detergent industry.

  7. Determination of membrane degradation products in the product water of polymer electrolyte membrane fuel cells using liquid chromatography mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zedda, Marco

    2011-05-12

    The predominant long term failure of polymer electrolyte membranes (PEM) is caused by hydroxyl radicals generated during fuel cell operation. These radicals attack the polymer, leading to chain scission, unzipping and consequently to membrane decomposition products. The present work has investigated decomposition products of novel sulfonated aromatic hydrocarbon membranes on the basis of a product water analysis. Degradation products from the investigated membrane type and the possibility to detect these compounds in the product water for diagnostic purposes have not been discovered yet. This thesis demonstrates the potential of solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) for the extraction, separation, characterization, identification and quantification of membrane degradation products in the product water of fuel cells. For this purpose, several polar aromatic hydrocarbons with different functional groups were selected as model compounds for the development of reliable extraction, separation and detection methods. The results of this thesis have shown that mixed mode sorbent materials with both weak anion exchange and reversed phase retention properties are well suited for reproducible extraction of both molecules and ions from the product water. The chromatographic separation of various polar aromatic hydrocarbons was achieved by means of phase optimized liquid chromatography using a solvent gradient and on a C18 stationary phase. Sensitive and selective detection of model compounds could be successfully demonstrated by the analysis of the product water using tandem mass spectrometry. The application of a hybrid mass spectrometer (Q Trap) for the characterization of unknown polar aromatic hydrocarbons has led to the identification and confirmation of 4-hydroxybenzoic acid in the product water. In addition, 4-HBA could be verified as a degradation product resulting from PEM decomposition by hydroxyl radicals using an

  8. Coilin phosphomutants disrupt Cajal body formation, reduce cell proliferation and produce a distinct coilin degradation product.

    Directory of Open Access Journals (Sweden)

    Zunamys I Carrero

    Full Text Available Coilin is a nuclear phosphoprotein that accumulates in Cajal bodies (CBs. CBs participate in ribonucleoprotein and telomerase biogenesis, and are often found in cells with high transcriptional demands such as neuronal and cancer cells, but can also be observed less frequently in other cell types such as fibroblasts. Many proteins enriched within the CB are phosphorylated, but it is not clear what role this modification has on the activity of these proteins in the CB. Coilin is considered to be the CB marker protein and is essential for proper CB formation and composition in mammalian cells. In order to characterize the role of coilin phosphorylation on CB formation, we evaluated various coilin phosphomutants using transient expression. Additionally, we generated inducible coilin phosphomutant cell lines that, when used in combination with endogenous coilin knockdown, allow for the expression of the phosphomutants at physiological levels. Transient expression of all coilin phosphomutants except the phosphonull mutant (OFF significantly reduces proliferation. Interestingly, a stable cell line induced to express the coilin S489D phosphomutant displays nucleolar accumulation of the mutant and generates a N-terminal degradation product; neither of which is observed upon transient expression. A N-terminal degradation product and nucleolar localization are also observed in a stable cell line induced to express a coilin phosphonull mutant (OFF. The nucleolar localization of the S489D and OFF coilin mutants observed in the stable cell lines is decreased when endogenous coilin is reduced. Furthermore, all the phosphomutant cells lines show a significant reduction in CB formation when compared to wild-type after endogenous coilin knockdown. Cell proliferation studies on these lines reveal that only wild-type coilin and the OFF mutant are sufficient to rescue the reduction in proliferation associated with endogenous coilin depletion. These results emphasize

  9. Indications for a ubiquitous dissolved pigment degradation product in subsurface waters of the global ocean

    Directory of Open Access Journals (Sweden)

    R. Röttgers

    2011-10-01

    Full Text Available Measurements of light absorption by chromophoric dissolved organic matter (CDOM from sub-surface waters of the tropical Atlantic and Pacific showed a distinct absorption shoulder at 410–415 nm, indicating an underlying absorption of a pigment. A similar absorption maximum at ~410 nm was also found in the particulate fraction and is usually attributed to absorption by respiratory pigments of heterotrophic unicellular organisms. The CDOM absorption shoulder was described earlier in the Indian Ocean at 600 m depth and was related to a "deep red fluorescence" found in the same depth, i.e. in the oxygen minimum zone (Breves et al., 2003; Broenkow et al., 1983. In our study, fluorescence measurements of pre-concentrated DOM samples confirmed that the absorption at ~410 nm was related to a specific fluorescence at 650 nm. The absorption characteristic of this specific fluorophor was examined by fluorescence emission/excitation analysis and this showed a clear excitation maximum at 415 nm (in methanol that can explain the absorption shoulder in the CDOM spectra. The spectral characteristics of the substance found in the dissolved and particulate fraction did not match with those of chlorophyll a degradation products (as found in a sample from the sea surface but can be explained by the occurrence of respiratory pigments from heterotrophs. Combining the observations of the "deep red fluorescence" and the 410 nm-absorption shoulder suggests that there are high concentrations of a pigment degradation product (cytochrome c in DOM of all major oceans. Most pronouncedly we found this signal in the deep chlorophyll maximum and the oxygen minimum zone of tropical regions. The origin, chemical nature, turn-over rate, and fate of this molecule is so far unknown.

  10. Identification, Characterization, and Quantification of Impurities of Safinamide Mesilate: Process-Related Impurities and Degradation Products.

    Science.gov (United States)

    Zou, Liang; Sun, Lili; Zhang, Hui; Hui, Wenkai; Zou, Qiaogen; Zhu, Zheying

    2017-07-01

    The characterization of process-related impurities and degradation products of safinamide mesilate (SAFM) in bulk drug and a stability-indicating HPLC method for the separation and quantification of all the impurities were investigated. Four process-related impurities (Imp-B, Imp-C, Imp-D, and Imp-E) were found in the SAFM bulk drug. Five degradation products (Imp-A, Imp-C, Imp-D, Imp-E, and Imp-F) were observed in SAFM under oxidative conditions. Imp-C, Imp-D, and Imp-E were also degradation products and process-related impurities. Remarkably, one new compound, identified as (S)-2-[4-(3-fluoro-benzyloxy) benzamido] propanamide (i.e., Imp-D), is being reported here as an impurity for the first time. Furthermore, the structures of the aforementioned impurities were characterized and confirmed via IR, NMR, and MS techniques, and the most probable formation mechanisms of all impurities proposed according to the synthesis route. Optimum separation was achieved on an Inertsil ODS-3 column (250 × 4.6 mm, 5 μm), using 0.1% formic acid in water (pH adjusted to 5.0) and acetonitrile as the mobile phase in gradient mode. The proposed method was found to be stability-indicating, precise, linear, accurate, sensitive, and robust for the quantitation of SAFM and its process-related substances, including its degradation products.

  11. Identification of a new degradation product of the antifouling agent Irgarol 1051 in natural samples

    Science.gov (United States)

    Ferrer, I.; Barcelo, D.

    2001-01-01

    A main degradation product of Irgarol [2-(methylthio)-4-(tert-butylamino)-6-(cyclopropylamino)-s-triazine], one of the most widely used compounds in antifouling paints, was detected at trace levels in seawater and sediment samples collected from several marinas on the Mediterranean coast. This degradation product was identified as 2-methylthio-4-tert-butylamino-s-triazine. The unequivocal identification of this compound in seawater samples was carried out by solid-phase extraction (SPE) coupled on-line with liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS). SPE was carried out by passing 150 ml of seawater sample through a cartridge containing a polymeric phase (PLRP-s), with recoveries ranging from 92 to 108% (n=5). Using LC-MS detection in positive ion mode, useful structural information was obtained by increasing the fragmentor voltage, thus permitting the unequivocal identification of this compound in natural samples. Method detection limits were in the range of 0.002 to 0.005 ??g/l. Overall, the combination of on-line SPE and LC-APCI-MS represents an important advance in environmental analysis of herbicide degradation products in seawater, since it demonstrates that trace amounts of new polar metabolites may be determined rapidly. This paper reports the LC-MS identification of the main degradation product of Irgarol in seawater and sediment samples. ?? 2001 Elsevier Science B.V. All rights reserved.

  12. Urinary collagen degradation products as early markers of progressive renal fibrosis

    DEFF Research Database (Denmark)

    Hijmans, Ryanne S.; Rasmussen, Daniel Guldager Kring; Yazdani, Saleh

    2017-01-01

    Background: Renal fibrogenesis is associated with increased ECM remodeling and release of collagen fragments in urine in progressive renal disease. We investigated the diagnostic value of urinary collagen degradation products in a proteinuria-driven fibrosis rat model with and without anti-fibrot...

  13. Effect of enzyme additions on methane production and lignin degradation of landfilled sample of municipal solid waste.

    Science.gov (United States)

    Jayasinghe, P A; Hettiaratchi, J P A; Mehrotra, A K; Kumar, Sunil

    2011-04-01

    Operation of waste cells as landfill bioreactors with leachate recirculation is known to accelerate waste degradation and landfill gas generation. However, waste degradation rates in landfill bioreactors decrease with time, with the accumulation of difficult to degrade materials, such as lignin-rich waste. Although, potential exists to modify the leachate quality to promote further degradation of such waste, very little information is available in literature. The objective of this study was to determine the viability of augmenting leachate with enzymes to increase the rate of degradation of lignin-rich waste materials. Among the enzymes evaluated MnP enzyme showed the best performance in terms of methane yield and substrate (lignin) utilization. Methane production of 200 mL CH(4)/g VS was observed for the MnP amended reactor as compared to 5.7 mL CH(4)/g VS for the control reactor. The lignin reduction in the MnP amended reactor and control reactor was 68.4% and 6.2%, respectively.

  14. Free-radical-induced oxidative and reductive degradation of fluoroquinolone pharmaceuticals: kinetic studies and degradation mechanism.

    Science.gov (United States)

    Santoke, Hanoz; Song, Weihua; Cooper, William J; Greaves, John; Miller, George E

    2009-07-09

    Fluoroquinolones, as a class of broad-spectrum antibiotics, have been detected in both surface and ground waters, and advanced oxidation/reduction processes (AO/RPs) are currently in development to remove these and other pharmaceuticals from wastewater because currently utilized treatment methods have proven to be ineffective. This article reports the reaction kinetics of six common fluoroquinolones with hydroxyl radicals and hydrated electrons, which are the major reactive species involved in AO/RPs. The bimolecular reaction rate constants (M(-1) s(-1)) for orbifloxacin, flumequine, marbofloxacin, danofloxacin, enrofloxacin, and the model compound, 6-fluoro-4-oxo-1,4-dihydro-3-quinoline carboxylic acid, with *OH are (6.94 +/- 0.08) x 10(9), (8.26 +/- 0.28) x 10(9), (9.03 +/- 0.39) x 10(9), (6.15 +/- 0.11) x 10(9), (7.95 +/- 0.23) x 10(9), (7.65 +/- 0.20) x 10(9), and with e(aq)(-), (2.25 +/- 0.02) x 10(10), (1.83 +/- 0.01) x 10(10), (2.41 +/- 0.02) x 10(10), (1.68 +/- 0.02) x 10(10), (1.89 +/- 0.02) x 10(10), and (1.49 +/- 0.01) x 10(10). These rate constants are related to the functional groups attached to the quinolone core, particularly the steric hindrance of the piperazine ring, making it possible to obtain a preliminary estimate of the *OH rate constant of an arbitrary fluoroquinolone by observing the ring constituents. In addition, the products of gamma-irradiation degradation of fluoroquinolones were analyzed by LC-MS to elucidate the probable pathways of AO/RPs degradation. Results indicate that preliminary degradation pathways include hydroxyl radical attack on the aromatic ring with subsequent hydroxylation, the substitution of a fluorine atom with a hydroxyl group, and the removal of the piperazine-derived side chain.

  15. Comparison of N-nitrosodiethylamine degradation in water by UV irradiation and UV/O{sub 3}: Efficiency, product and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Xu Bingbing, E-mail: xbb_hit@126.com [State Environmental Protection Key Laboratory for Lake Pollution Control, Chinese Research Academy of Environmental Sciences, Beijing 100021 (China) and State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chen Zhonglin, E-mail: zhonglinchen@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Qi Fei [College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083 (China); Ma Jun [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Wu Fengchang [State Environmental Protection Key Laboratory for Lake Pollution Control, Chinese Research Academy of Environmental Sciences, Beijing 100021 (China)

    2010-07-15

    N-Nitrosodiethylamine (NDEA) is a member of nitrosamines, which is strong carcinogenic. In order to explore an effective treatment method for NDEA removal from water, sole UV irradiation and UV/O{sub 3} were carried out in this study. The removal efficiency, degradation products and pathways were compared between those two processes. Results showed that NDEA removal efficiency achieved 99% within 15 min by both UV and UV/O{sub 3.} Degradation reaction well followed pseudo-first-order kinetics. Water pH had different effect on NDEA degradation in those two processes. Acidic and neutral conditions were good for NDEA degradation by sole UV irradiation. However, NDEA underwent rapid degradation under various pH conditions in the UV/O{sub 3} process. Though the ozone introduction in the UV/O{sub 3} process had little effect on NDEA degradation efficiency, it had significant effect on its degradation products and pathways. Methylamine, dimethylamine, ethylamine and diethylamine were observed as aliphatic amine products of NDEA degradation in both two processes. They were assumed to arise due to N-N bond fission under UV irradiation, or due to the reaction of NDEA and hydroxyl radicals in the UV/O{sub 3} process.

  16. Bilirubin degradation in methanol induced by continuous UV-B irradiation: a UHPLC--ESI-MS study.

    Science.gov (United States)

    Stanojević, J S; Zvezdanović, J B; Marković, D Z

    2015-04-01

    Degradation of bilirubin in aerobic methanol solution by continuous UV-B irradiation has been investigated in this work. The purpose of this study was to shed more light on bilirubin interaction with the UV-B component of natural sunlight, since bilirubin is a very efficient UV-B absorber located in the skin epidermis. The degradation products have been detected and studied by a combined method of Ultra High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry (UHPLC-ESI-MS). Bilirubin, a toxic pigment which itself is a product of (hemoglobin) degradation in organisms, undergoes its own degradation under aerobic conditions of UV-B continuous irradiation (e.g. photooxidation) that can be partly self-sensitized. Two dipyrrolic structures have been identified as a result of the bilirubin degradation, not including the bilirubin derivative biliverdin whose increase in the irradiated system is synchronous with a time dynamics of bilirubin degradation. It appears that one of dipyrrolic products originates directly from bilirubin and biliverdin molecules, while the other one is probably connected to bilirubin self-sensitized degradation. The precursor role of biliverdin in the degradation process--related to the detected dipyrroles--has not been confirmed.

  17. Stimulation of diesel degradation and biosurfactant production by aminoglycosides in a novel oil-degrading bacterium Pseudomonas luteola PRO23

    Directory of Open Access Journals (Sweden)

    Atanasković Iva M.

    2016-01-01

    Full Text Available Bioremediation is promising technology for dealing with oil hydrocarbons contamination. In this research growth kinetics and oil biodegradation efficiency of Pseudomonas luteola PRO23, isolated from crude oil-contaminated soil samples, were investigated under different concentrations (5, 10 and 20 g/L of light and heavy crude oil. More efficient biodegradation and more rapid adaptation and cell growth were obtained in conditions with light oil. The 5 to 10 g/L upgrade of light oil concentration stimulated the microbial growth and the biodegradation efficiency. Further upgrade of light oil concentration and the upgrade of heavy oil concentration both inhibited the microbial growth, as well as biodegradation process. Aminoglycosides stimulated biosurfactant production in P. luteola in the range of sub-inhibitory concentrations (0.3125, 0.625 μg/mL. Aminoglycosides also induced biofilm formation. The production of biosurfactants was the most intense during lag phase and continues until stationary phase. Aminoglycosides also induced changes in P. luteola growth kinetics. In the presence of aminoglycosides this strain degraded 82% of diesel for 96 h. These results indicated that Pseudomonas luteola PRO23 potentially can be used in bioremediation of crude oil-contaminated environments and that aminoglycosides could stimulate this process. [Projekat Ministarstva nauke Republike Srbije, br. TR31080

  18. STUDY OF DEGRADATION MECHANISM AND PACKAGING OF ORGANIC LIGHT EMITTING DEVICES

    Institute of Scientific and Technical Information of China (English)

    Gu Xu

    2003-01-01

    Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in future Flat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to their commercialization. Here we present a brief summary of our studies on both extrinsic and intrinsic causes for the fast degradation of OLEDs. In particular, we focus on the origin of the dark spots by "rebuilding" cathodes, which confirms that the growth of dark spots occurs primarily due to cathode delamination. In the meantime, we recapture the findings from the search for suitable OLED packaging materials, in particular polymer composites, which provide both heat dissipation and moisture resistance, in addition to electrical insulation.

  19. Degradation of atrazine by UV/chlorine: Efficiency, influencing factors, and products.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Liu, Weili; Liu, Yulei

    2016-03-01

    In this work, the degradation of atrazine by the combination of UV and chlorine (UV/chlorine) due to the formation of radicals during chlorine photolysis was systematically investigated in terms of efficiency, factors that influence the degradation kinetics, as well as oxidation products. It was found that the degradation efficiency of atrazine was enhanced by UV/chlorine compared to UV or chlorine alone. The degradation efficiency of atrazine was favorable at a lower pH, but was inhibited in the presence of natural organic matters. Meanwhile, the initial chlorine dosage, alkalinity, and chloride barely influenced the degradation efficiency under neutral pH conditions. The degradation of atrazine by UV/chlorine was inhibited in real waters (i.e., surface water and ground water) compared to in deionized water but was still more effective than UV alone. The oxidation products of atrazine resulting from de-alkylation, dechlorination-hydroxylation, alkylic-hydroxylation, alkylic-oxidation, alkylic-hydroxylation-dehydration, deamination-hydroxylation, and dechlorination-hydrogenation in UV/chlorine process were detected, which were slightly different from those formed in UV/H2O2 (commonly used UV-based advanced oxidation process). Particularly, the yields of three primary transformation products (desethyl-atrazine (DEA), desisopropyl-atrazine (DIA), and desethyl-desisopropyl-atrazine (DEIA)) were comparatively quantified in these two processes. The different trend of them formed in UV/chlorine system (DEA:DIA≈4) compared to that formed in UV/H2O2 system (DEA:DIA≈1) could be ascribed to the different reaction reactivities and mechanisms between HO• and Cl• with atrazine.

  20. New microbiological assay for determination of caspofungin in the presence of its degradation products and its measurement uncertainty.

    Science.gov (United States)

    Ghisleni, Daniela Dal Molim; Okamoto, Rogério Takao; De Oliveira, Amaral Cleide Maria; Lourenço, Felipe Rebello; De Jesus, Andreoli Pinto Terezinha

    2014-01-01

    Caspofungin is an echinocandin antifungal used in the treatment of invasive fungal infections. Several methods have been reported for the quantitative analysis of echinocandins; however, there is no microbiological assay for determination of caspofungin potency in the presence of its degradation products. This study aimed to develop and validate a microbiological method for quantitative analysis of caspofungin in lyophilized powder, evaluate the stability, and determinate the degradation kinetics of the drug when the finished product is submitted to heat stress. A procedure was established to estimate measurement uncertainty for routine analysis. The validation was performed as recommended in the current official guidelines. The agar diffusion method is based on the inhibitory effect of caspofungin on Candida albicans. Results showed selectivity, linearity, precision, and accuracy of the method. Statistical analysis demonstrated that method is linear (in the range 2.5 to 16 microg/mL, y= 15.73 + 6.4x, r2 = 0.9965), precise (intermediate precision: 2.54%), and accurate (recovery range: 95.01-102.46%). The proposed method allowed evaluation of the thermal stability of the drug at 80 degreesC for 120 min and determination of first order degradation kinetics. The variability of inhibition zone sizes was the most important source of uncertainty at about 87% of the overall uncertainty (103.0+/-1.7%). These results show that the proposed method is applicable to routine laboratory testing, and is sensitive to thermal degradation of caspofungin.

  1. Photolytic and photocatalytic degradation of quinclorac in ultrapure and paddy field water: identification of transformation products and pathways.

    Science.gov (United States)

    Pareja, Lucía; Pérez-Parada, Andrés; Agüera, Ana; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, Amadeo R

    2012-05-01

    Quinclorac (QNC) is an effective but rather persistent herbicide commonly used in rice production. This herbicide presents a mean persistence in the environment so its residues are considered of environmental relevance. However, few studies have been conducted to investigate its environmental behavior and degradation. In the present work, direct photolysis and TiO(2) photocatalysis of the target compound in ultrapure and paddy field water were investigated. After 10h photolysis in ultrapure water, the concentration of QNC declined 26% and 54% at 250 and 700 W m(-2), respectively. However, the amount of quinclorac in paddy field water remained almost constant under the same irradiation conditions. QNC dissipated completely after 40 min of TiO(2) photocatalysis in ultrapure water, whereas 130 min were necessary to degrade 98% of the initial concentration in paddy field water. Possible QNC photolytic and photocatalytic degradation pathways are proposed after structure elucidation of the main transformation products, through liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry and exact mass measurements. Pyridine ring hydroxylation at C-9 followed by ring opening and/or oxidative dechlorination were the key steps of QNC degradation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. [Analysis of alkaline CuO degradation products of acid detergent fiber from tobacco leaves by using liquid chromatography].

    Science.gov (United States)

    Hao, Weiqiang; Wang, Leijun; Wu, Shun; Yue, Bangyi; Chen, Qiang; Zhang, Peipei

    2015-07-01

    The acid detergent fiber (ADF) from tobacco leaves was obtained by treating the sample with petroleum ether-ethanol (6:4, v/v), 30 g/L sodium dodecylsulfate and 0.5 mol/L sulphuric acid containing 20 g/L hexadecyl trimethyl ammonium bromide successively. The ADF was degraded by the alkaline CuO oxidation procedure. In this work, six samples of ADF degradation products from tobacco leaves were prepared. The samples were analyzed by using gradient liquid chromatography (LC) where an Ultimate XB C18 column was used as stationary phase, with a mixture of methanol and water as mobile phase, at a column temperature of 35 °C and a flow rate of 0.8 mL/min. Dual wavelengths of 280 nm and 320 nm were chosen for the detection. It was found that there were four characteristic peaks for the ADF degradation products. By taking these peaks as research object, the optimum time for the degradation was found to be 5 h and the sample solution could be kept stable within 7 days. The established method may provide a new approach for the studies of the differences between lignin composition in different tobacco leaves and the relationship between lignin content and the smoking quality of tobacco leaves.

  3. Degradation study of phenol on pillared clay catalyst

    Directory of Open Access Journals (Sweden)

    Julio Andrés Cardona Castaño

    2016-08-01

    Full Text Available The pillaring of a Colombian natural clay (bentonite with the Al-Fe systems and the application for catalytic wet peroxide oxidation (CWPO using phenol as target compound at 291,15 K has been studied. The solid was characterized by DRX and specific surface area using the BET model. The experiments were conducted at temperature of 291,15 K, atmospheric pressure, phenol concentration of 100 mg/L, catalyst concentration of  0,5 and  2,75 g/L and hydrogen peroxide concentration of  0,0265 and 0,053 M in semibatch and 7,4x10-3 and 0,0148 M in batch, equivalent to 50 and 100% of the stoichiometric amount needed for complete phenol degradation, respectively.Both processes were compared in terms of degradation of phenol, degradation of H2O2 and aromatic intermediates and short chain acids. It was determined that the rate of degradation of phenol and aromatic intermediates is slower in the semibatch process. However, more efficient hydrogen peroxide in the semibatch process was presented use favoring reaction with organic species and reducing competitive reactions.

  4. Degradation of polyethylene glycol by Fenton reaction: a comparative study.

    Science.gov (United States)

    Haseneder, R; Fdez-Navamuel, B; Härtel, G

    2007-01-01

    Photochemical advanced oxidation processes (AOPs) utilising different Fenton systems were investigated in laboratory-scale experiments for the degradation of polyethylene glycol (PEG). The results of the study showed that the degradation rate of PEG was strongly accelerated by the homogeneous system, and this proved to be advantageous in comparison to the heterogeneous system. Between Fenton and photo-Fenton heterogeneous systems, the photo-Fenton process reached the highest removal rate of the organic compound, due to the enhanced reduction efficiency of Fe(III) to Fe(II) under UV-irradiation. The oxidation rate in the heterogeneous system was investigated using varying different parameters, such as the pH value, the concentration of hydrogen peroxide and the amount of Fe(OH)3 as the catalyst. For the homogeneous Fenton system the rate of degradation is significantly higher. At the same time of operation the elimination rates can be found to be 30% over the rates of the heterogeneous system. Optimising the typical influence parameters mentioned before, a degradation of about 93% of PEG can be achieved by using the homogeneous Fenton system.

  5. The degradation of lining of rotary furnaces in the production of zinc oxide

    Directory of Open Access Journals (Sweden)

    Natália Luptáková

    2014-06-01

    Full Text Available This paper is closely connected with the complex problem of degradation relating to the refractories of rotary furnace linings in the production of zinc oxide. Zinc oxide can be produced by variety of ways, but the most common method of production which is used in Europe is indirect, i.e. pyrolytic combustion of zinc. This method is also called "French process" of manufacturing ZnO. But this mentioned method of preparation leads to the creation of the enormous amount of zinc slag including chemical complexes of elements Fe, Zn and Al. The mechanism of degradation of the lining leads to slag rests and it is closely connected with the mutual interaction of the aggressive agents with the components of the lining. This process creates a new undesired surface layer which increased the overall thickness of zinc slag. Stuck slag has the influence on rapid degradation of the linings and moreover it also decreases the production quality of ZnO. Analysis results introduced in this paper are significant information for minimizing of degradation of rotary furnaces.  

  6. Evaluating the degradation, sorption, and negative mass balances of pharmaceuticals and personal care products during wastewater treatment.

    Science.gov (United States)

    Blair, Benjamin; Nikolaus, Adam; Hedman, Curtis; Klaper, Rebecca; Grundl, Timothy

    2015-09-01

    Conventional activated sludge (CAS) wastewater treatment processes are insufficient at removing many pharmaceutical and personal care products (PPCPs) from wastewater. In addition, negative mass balances, where the effluent concentration is greater than the influent concentration, have been observed in wastewater treatment studies and a further understanding of these results is needed. In this study, the fate and occurrence of 57 PPCPs and hormones were evaluated in an activated sludge process and the mass balances were determined. The goal of the project was to understand the PPCPs biological degradation and the extent of sorption to solids. The samples containing in situ PPCPs (i.e. samples were not spiked with additional PPCPs) were evaluated. Forty-eight of the PPCPs were detected in the soluble form and 29 were detected sorbed to solids. Two notable results were found. First, the results of this study indicate a subset of the highly biodegradable PPCPs stop being degraded at low, yet notable, concentrations. Second, the results revealed that negative mass balances were present for a subset of the PPCPs when evaluating both the soluble and sorbed concentration, for example carbamazepine and ofloxacin. Desorption from solids was not found to attribute to negative mass balances. Overall, the results from this study provide new insights into the fate of PPCPs during CAS wastewater treatment by evaluating the degradation kinetics and sorption and the results may explain the consistent levels of highly degradable PPCPs being emitted from WWTPs worldwide. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Assessment of the degradation efficiency of full-scale biogas plants: A comparative study of degradation indicators.

    Science.gov (United States)

    Li, Chao; Nges, Ivo Achu; Lu, Wenjing; Wang, Haoyu

    2017-07-29

    Increasing popularity and applications of the anaerobic digestion (AD) process has necessitated the development and identification of tools for obtaining reliable indicators of organic matter degradation rate and hence evaluate the process efficiency especially in full-scale, commercial biogas plants. In this study, four biogas plants (A1, A2, B and C) based on different feedstock, process configuration, scale and operational performance were selected and investigated. Results showed that the biochemical methane potential (BMP) based degradation rate could be use in incisively gauging process efficiency in lieu of the traditional degradation rate indicators. The BMP degradation rates ranged from 70 to 90% wherein plants A2 and C showed the highest throughput. This study, therefore, corroborates the feasibility of using the BMP degradation rate as a practical tool for evaluating process performance in full-scale biogas processes and spots light on the microbial diversity in full-scale biogas processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Organic matter degradation in Lake Baikal - a sediment trap study

    DEFF Research Database (Denmark)

    Schubert, Carsten J.; Niggemann, Jutta; Lomstein, Bente Aagaard

    Lake Baikal offers a unique opportunity to study water column processes in a freshwater system with conditions similar to oceanic systems, e. g. great water depth and oxygenated water column. Investigations on sediment trap material provide information on the early stages of organic matter...... and composition of amino acids and fatty acids. The extent of organic matter degradation in the water column of Lake Baikal is reflected in the fluxes of total organic carbon, chlorins, amino acids, and fatty acids at different water depths. In line with earlier studies in marine systems, the labile compounds......, and the Fatty Acid Index [2]. All indicators showed consistent trends, indicating that the diagenetic stage of the sediment trap material increased with increasing water depth. This study of sediment trap material from Lake Baikal provided interesting insights in organic matter degradation in this unique...

  9. Degradation of the synthetic dye amaranth by the fungus Bjerkandera adusta Dec 1: inference of the degradation pathway from an analysis of decolorized products.

    Science.gov (United States)

    Gomi, Nichina; Yoshida, Shuji; Matsumoto, Kazutsugu; Okudomi, Masayuki; Konno, Hiroki; Hisabori, Toru; Sugano, Yasushi

    2011-11-01

    We examined the degradation of amaranth, a representative azo dye, by Bjerkandera adusta Dec 1. The degradation products were analyzed by high performance liquid chromatography (HPLC), visible absorbance, and electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS). At the primary culture stage (3 days), the probable reaction intermediates were 1-aminonaphthalene-2,3,6-triol, 4-(hydroxyamino) naphthalene-1-ol, and 2-hydroxy-3-[2-(4-sulfophenyl) hydrazinyl] benzenesulfonic acid. After 10 days, the reaction products detected were 4-nitrophenol, phenol, 2-hydroxy-3-nitrobenzenesulfonic acid, 4-nitrobenzene sulfonic acid, and 3,4'-disulfonyl azo benzene, suggesting that no aromatic amines were created. Manganese-dependent peroxidase activity increased sharply after 3 days culture. Based on these results, we herein propose, for the first time, a degradation pathway for amaranth. Our results suggest that Dec 1 degrades amaranth via the combined activities of peroxidase and hydrolase and reductase action.

  10. Experimental study of the degradation of 2,4-D induced by vacuum-UV radiation.

    Science.gov (United States)

    Imoberdorf, G E; Mohseni, M

    2011-01-01

    Vacuum-UV (VUV) photoinduced degradation of the herbicide 2,4-D was studied. A flow-through VUV photoreactor was used (i) in batch mode to study the kinetics of degradation and (ii) in continuous mode under steady state to analyze the potential utilization of this process in commercial applications. In both cases, the reactants were recycled to minimize diffusive resistances. Experimental results from the batch studies showed that the initial degradation rate of 2,4-D in ultrapure water was independent of the initial concentration of the herbicide. However, a reduction in the reaction rate was obtained over the course of the treatment, largely due to the formation of 2,4-D partial oxidation by-products which compete with 2,4-D molecules for HO (scavenging effect). Increases in water alkalinity reduced 2,4-D degradation rate as a consequence of the scavenging of HO by carbonates and bicarbonates. The degradation of 2,4-D in raw surface waters was also investigated. A noticeable reduction in the degradation rate was observed because of the presence of NOM and alkalinity, both being known HO scavengers. Additionally, the presence of inorganic species/ions that absorb VUV may also have contributed to the reduction of the overall degradation rate. High conversions were obtained in the continuous system. At a residence time of 25 seconds, conversions of 97% and 65% were achieved for inlet herbicide concentrations of 1 and 10 mg L(-1), respectively. Under these conditions, the received dose of 185 nm radiation was 44.8 mJ cm(-2).

  11. Microbial degradation of chitin waste for production of chitosanase and food related bioactive compounds.

    Science.gov (United States)

    Sinha, S; Chand, S; Tripathi, P

    2014-01-01

    Ecological samples rich in microbial diversity like cow dung, legume rhizosphere, fish waste and garden soil were used for isolation of chitosan-degrading microorganisms. Selected isolates were used for production of chitosanase and food related bioactive compounds by conversion of biowaste. Production of glucosamine (Gln), N-acetylglucosamine (NAG), chitooligosaccharides (COS), antioxidants, antibacterial compounds and prebiotics was carried out by microbial fermentation of biowaste. The highest chitosanase activity (8 U/mL) was observed in Aspergillus sp. isolated from fish market waste and it could produce Gln and NAG while Streptomyces sp. isolated from garden soil was able to produce COS along with Gln and NAG. Radical scavenging activity was observed in culture supernatants of 35% of studied isolates, and 20% isolates secreted compounds which showed positive effect on growth of Bifidobacterium. Antibacterial compounds were produced by 40% of selected isolates and culture supernatants of two microbial isolates, Streptomyces zaomyceticus C6 and one of garden soil isolates, were effective against both gram positive and negative bacteria.

  12. Determination of degradation products of squalamine lactate using LC/MS.

    Science.gov (United States)

    Li, Cong-Jun; Kari, U Prasad; Noecker, Lincoln A; Jones, Stephen R; Sabo, Andrew M; McCormick, Timothy J; Johnston, Sean M

    2003-04-24

    Heat, acid and base stress methods were applied to study the stability of squalamine lactate. Liquid chromatography coupled with mass spectrometry was used to analyze the degraded samples and tentative structural identifications were assigned based on their molecular weight measurements, reactivity and MS/MS fragmentation. Solid squalamine lactate generated a new amide, namely lactyl squalamide, when heated to 80 degrees C. Chemical structure for this new compound has been established by NMR and MS data interpretation and confirmed by direct comparison between the degradant and the synthesized compound. Squalamine lactate in pH 4 acetate buffer solution produced more degradants under stressed conditions. These degradants are formed due to the loss of the sulfate functionality. Squalamine lactate is stable in refrigerated conditions as well as in basic solution.

  13. Stress degradation studies and stability-indicating TLC-densitometric method of glycyrrhetic acid.

    Science.gov (United States)

    Musharraf, Syed Ghulam; Kanwal, Nayab; Arfeen, Qamar Ul

    2013-01-17

    Glycyrrhetic acid, a pentacyclic triterpenoid, possesses a broad range of pharmacological activities and serves as template to synthesize many bioactive drugs. This paper describes a simple, accurate, and sensitive stability-indicating TLC densitometric method for the determination of glycyrrhetic acid and its degradation product as per the ICH guidelines. Separation was carried out on TLC aluminium sheet pre-coated with silica gel 60F254 using chloroform, methanol and formic acid (9:0.9:0.1, v/v). Compact spot for glycyrrhetic acid was found at Rf value of 0.42 ± 0.03. Densitometric analysis was carried out in the absorbance mode at λmax 254 nm. Glycyrrhetic acid was found to be stable to the exposure of base, neutral, oxidation, dry heating treatment and wet heating treatment, but showed degradation under acidic and photochemical conditions. Moreover, fragmentation pattern of glycyrrhetic acid was developed by using a positive ion electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QqTOF-MS/MS) hybrid instrument. A photo-degraded product was characterized through comparison of mass spectrometric studies with glycyrrhetic acid. The developed stability-indicating TLC-densitometric method can be applied for routine analysis of glycyrrhetic acid in the presence of its degradation products.

  14. Degradation studies on plasticized PVC films submited to gamma radiation

    Directory of Open Access Journals (Sweden)

    Vinhas Glória Maria

    2003-01-01

    Full Text Available Poly (vinyl chloride, PVC, is a rigid polymer and for several of its applications must be compounded with plasticizing agents. The plasticizers minimize the dipolar interactions, which exist between the polymer's chains, promoting their mobility. In this work we studied the properties of PVC/plasticizer systems submitted to different doses of gamma radiation. We have used four commercial plasticizers amongt them di(2-ethylhexyl phthalate, DEHP, which is present in a great number of commercial applications. The PVC/plasticizer systems have been studied as films made by the solvent evaporation technique. Irradiated and non-irradiated films have been characterized by viscosimetric analysis, mechanical essays and infrared spectroscopy. The results have shown that the rigid, non plasticized, PVC film presented the greatest degradation index, while among the plasticized films the one which presented the larger degradation index due to chain scission was the DEHP plasticized PVC.

  15. PEGylated single-walled carbon nanotubes activate neutrophils to increase production of hypochlorous acid, the oxidant capable of degrading nanotubes.

    Science.gov (United States)

    Vlasova, Irina I; Vakhrusheva, Tatyana V; Sokolov, Alexey V; Kostevich, Valeria A; Gusev, Alexandr A; Gusev, Sergey A; Melnikova, Viktoriya I; Lobach, Anatolii S

    2012-10-01

    Perspectives for the use of carbon nanotubes in biomedical applications depend largely on their ability to degrade in the body into products that can be easily cleared out. Carboxylated single-walled carbon nanotubes (c-SWCNTs) were shown to be degraded by oxidants generated by peroxidases in the presence of hydrogen peroxide. In the present study we demonstrated that conjugation of poly(ethylene glycol) (PEG) to c-SWCNTs does not interfere with their degradation by peroxidase/H(2)O(2) system or by hypochlorite. Comparison of different heme-containing proteins for their ability to degrade PEG-SWCNTs has led us to conclude that the myeloperoxidase (MPO) product hypochlorous acid (HOCl) is the major oxidant that may be responsible for biodegradation of PEG-SWCNTs in vivo. MPO is secreted mainly by neutrophils upon activation. We hypothesize that SWCNTs may enhance neutrophil activation and therefore stimulate their own biodegradation due to MPO-generated HOCl. PEG-SWCNTs at concentrations similar to those commonly used in in vivo studies were found to activate isolated human neutrophils to produce HOCl. Both PEG-SWCNTs and c-SWCNTs enhanced HOCl generation from isolated neutrophils upon serum-opsonized zymosan stimulation. Both types of nanotubes were also found to activate neutrophils in whole blood samples. Intraperitoneal injection of a low dose of PEG-SWCNTs into mice induced an increase in percentage of circulating neutrophils and activation of neutrophils and macrophages in the peritoneal cavity, suggesting the evolution of an inflammatory response. Activated neutrophils can produce high local concentrations of HOCl, thereby creating the conditions favorable for degradation of the nanotubes.

  16. In vitro degradability and total gas production of biodiesel chain byproducts used as a replacement for cane sugar feed

    OpenAIRE

    2014-01-01

    This study aimed to determine the in vitro degradability of dry matter and the total gas production of oil seed press cake from biodiesel production (Gossypium hirsutum L., Helianthus annuus L., Ricinus communis, Moringa oleífera L. and Pinhão manso curcas L.) at four different levels of replacement (0, 30, 50, and 70%) for cane sugar (Saccharum officinarum RB.) in ruminant feed. Inocula were prepared using the ruminal fluid of three Holstein cows, and data were collected after 48 hours of in...

  17. Studies on Thermal Degradation of Cellulosic Fibers Treated with Flame Retardants

    Institute of Scientific and Technical Information of China (English)

    高明; 戴秋菊

    2006-01-01

    Hemp fabric, one of the most flammable materials, was treated with the compounds containing different kinds of elements that contribute to flame retardation. For a study of flame retardation from the standpoint of thermal degradation, the samples were subjected to thermogravimetry (TG) and differential thermal analysis (DTA) in air from ambient temperature to 600 ℃. The apparent activation energy (Ea) is evaluated by Broido's method at different stages of thermal degradation to observe the variation of Ea in the process of thermal degradation. Flame retardation of samples was determined by limiting oxygen index (LOI) to find the effects of different compounds on flammability and the thermal degradation of hemp fabric.The composition of the chars was studied by the IR spectra to obtain information concerning the thermal degradation mechanism. Compared with flammable hemp, the hemp fabric treated with flame retardants showed a higher LOI, and lower Ea and decomposition temperatures, which indicates that some compounds make the hemp fabric decompose at lowertemperatures, resulting in less flammable products.

  18. A resource recycling technique of hydrogen production from the catalytic degradation of organics in wastewater

    Institute of Scientific and Technical Information of China (English)

    LI XiaoNian; ZHANG QunFeng; KONG LingNiao; XIANG YiZhi; JU YaoMing; WU XiaoQiong; FENG Feng; YUAN JunFeng; MA Lei; LU ChunShan

    2008-01-01

    A resource recycling technique of hydrogen production from the catalytic degradation of organics in wastewater by aqueous phase reforming (APR) has been proposed. It is worthy of noting that this technique may be a potential way for the purification of refractory and highly toxic organics in water for hydrogen production. Hazardous organics (such as phenol, aniline, nitrobenzene, tetrahydrofuran (THF), toluene, N,N-dimethylformamide (DMF) and cyclohexanol) in water could be completely de-graded into H2 and CO2 with high selectivity over Raney Ni, and Sn-modified Raney Ni (Sn-Raney-Ni) or Pd/C catalyst under mild conditions. The experimental results operated in tubular and autoclave reactors, indicated that the degradation degree of organics and H2 selectivity could reach 100% under the optimal reaction conditions. The Sn-Raney-Ni (Sn/Ni=0.06) and Pd/C catalysts show better catalytic performances than the Raney Ni catalyst for the degradation of organics in water into H2 and CO2 by the aqueous phase reforming process.

  19. Degradation of Acetaminophen and Its Transformation Products in Aqueous Solutions by Using an Electrochemical Oxidation Cell with Stainless Steel Electrodes

    Directory of Open Access Journals (Sweden)

    Miguel Ángel López Zavala

    2016-09-01

    Full Text Available In this study, a novel electrochemical oxidation cell using stainless steel electrodes was found to be effective in oxidizing acetaminophen and its transformation products in short reaction times. Aqueous solutions of 10 mg/L-acetaminophen were prepared at pH 3, 5, 7, and 9. These solutions were electrochemically treated at direct current (DC densities of 5.7 mA/cm2, 7.6 mA/cm2, and 9.5 mA/cm2. The pharmaceutical and its intermediates/oxidation products were determined by using high pressure liquid chromatography (HPLC. The results showed that electrochemical oxidation processes occurred in the cell. Acetaminophen degradation rate constants increased proportionally with the increase of current intensity. High current densities accelerated the degradation of acetaminophen; however, this effect diminished remarkably at pH values greater than 5. At pH 3 and 9.5 mA/cm2, the fastest degradation of acetaminophen and its intermediates/oxidation products was achieved. To minimize the wear down of the electrodes, a current density ramp is recommended, first applying 9.5 mA/cm2 during 2.5 min or 7.6 mA/cm2 during 7.5 min and then continuing the electrochemical oxidation process at 5.7 mA/cm2. This strategy will hasten the acetaminophen oxidation, extend the electrode’s life, and shorten the reaction time needed to degrade the pharmaceutical and its intermediates/oxidation products. DC densities up to 9.5 mA/cm2 can be supplied by photovoltaic cells.

  20. Enhancement in multiple lignolytic enzymes production for optimized lignin degradation and selectivity in fungal pretreatment of sweet sorghum bagasse.

    Science.gov (United States)

    Mishra, Vartika; Jana, Asim K; Jana, Mithu Maiti; Gupta, Antriksh

    2017-07-01

    The objective of this work was to study the increase in multiple lignolytic enzyme productions through the use of supplements in combination in pretreatment of sweet sorghum bagasse (SSB) by Coriolus versicolor such that enzymes act synergistically to maximize the lignin degradation and selectivity. Enzyme activities were enhanced by metallic salts and phenolic compound supplements in SSF. Supplement of syringic acid increased the activities of LiP, AAO and laccase; gallic acid increased MnP; CuSO4 increased laccase and PPO to improve the lignin degradations and selectivity individually, higher than control. Combination of supplements optimized by RSM increased the production of laccase, LiP, MnP, PPO and AAO by 17.2, 45.5, 3.5, 2.4 and 3.6 folds respectively for synergistic action leading to highest lignin degradation (2.3 folds) and selectivity (7.1 folds). Enzymatic hydrolysis of pretreated SSB yielded ∼2.43 times fermentable sugar. This technique could be widely applied for pretreatment and enzyme productions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Study of Operating Parameters for Accelerated Anode Degradation in SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    2017-01-01

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to demonstrate such exceptionally long lifetimes in ongoing R&D projects. Accelerated or compressed testing are alternative methods to obtain this. Activities in this area have been...... carried out without arriving at a generally accepted methodology. This is mainly due to the complexity of degradation mechanisms on the single SOFC components as function of operating parameters. In this study, we present a detailed analysis of approx. 180 durability tests regarding degradation of single...... SOFC components as function of operating conditions. Electrochemical impedance data were collected on the fresh and long-term tested SOFCs and used to de-convolute the individual losses of single SOFC cell components – electrolyte, cathode and anode. The main findings include a time-dependent effect...

  2. Study of degradation of epoxy resins under the action of partial discharges. Etude de degradation des resines epoxy sous l'action des decharges partielles

    Energy Technology Data Exchange (ETDEWEB)

    Hudon, C.

    1993-09-01

    Over the past few decades, epoxy resin composites have been extensively used in the high voltage insulation systems of rotating machines, notably large electric motors and hydroelectric power turbine generators. The actual life of these epoxy materials under high alternating voltage conditions is always shorter than predicted. Degradation of the epoxy results from a complex synergistic action of ionic and electronic surface bombardment, ultraviolet radiation, and electrochemical reactions in a confined and non-vented space that is in most cases inaccessible for careful observation and analysis. A comparative study was conducted using parallel-plane epoxy-covered electrodes to investigate the interrelation between the discharge signal behavior and the associated degradation. Examination of the behavior in terms of measured amplitude of the electrical pulse component and the light emission intensity disclosed the presence of three types of discharges. It was found that as a consequence of material degradation with time, the altered conditions within the discharge gap tended to favor a transition to even-smaller discharge amplitudes, and ultimately to a glow type discharge. Detailed chemical analyses of reaction products at the specimen surface indicated that the different discharge types, though leading to formation of different degradation products, contribute significantly in various degrees to the overall degradation of the epoxy resin. A model is proposed to explain the discharge signal transition process with time. It is based mainly on the measured increase of surface conductivity resulting from formation of degradation products, mostly composed of electrically conductive organic acids and nitric acid. 122 refs., 64 figs., 12 tabs.

  3. Photocatalytic degradation of rosuvastatin: Analytical studies and toxicity evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Tiele Caprioli, E-mail: tiele@enq.ufrgs.br [Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, CEP: 90040-040 Porto Alegre, RS (Brazil); Pizzolato, Tânia Mara [Chemical Institute, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CEP: 91501-970 Porto Alegre, RS (Brazil); Arenzon, Alexandre [Ecology Center, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CEP: 91501-970 Porto Alegre, RS (Brazil); Segalin, Jeferson [Biotechnology Center, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CEP: 91501-970 Porto Alegre, RS (Brazil); Lansarin, Marla Azário [Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, CEP: 90040-040 Porto Alegre, RS (Brazil)

    2015-01-01

    Photocatalytic degradation of rosuvastatin, which is a drug that has been used to reduce blood cholesterol levels, was studied in this work employing ZnO as catalyst. The experiments were carried out in a temperature-controlled batch reactor that was irradiated with UV light. Preliminary the effects of the photocatalyst loading, the initial pH and the initial rosuvastatin concentration were evaluated. The experimental results showed that rosuvastatin degradation is primarily a photocatalytic process, with pseudo-first order kinetics. The byproducts that were generated during the oxidative process were identified using nano-ultra performance liquid chromatography tandem mass spectrometry (nano-UPLC–MS/MS) and acute toxicity tests using Daphnia magna were done to evaluate the toxicity of the untreated rosuvastatin solution and the reactor effluent. - Highlights: • The photocatalytic degradation of rosuvastatin was studied under UV irradiation. • Commercial catalyst ZnO was used. • Initial rosuvastatin concentration, photocatalyst loading and pH were evaluated. • The byproducts generated during the oxidative process were detected and identified. • Acute toxicity tests using Daphnia magna were carried out.

  4. Characterization of forced degradation products of ketorolac tromethamine using LC/ESI/Q/TOF/MS/MS and in silico toxicity prediction.

    Science.gov (United States)

    Kalariya, Pradipbhai D; Raju, B; Borkar, Roshan M; Namdev, Deepak; Gananadhamu, S; Nandekar, Prajwal P; Sangamwar, Abhay T; Srinivas, R

    2014-05-01

    Ketorolac, a nonsteroidal anti-inflammatory drug, was subjected to forced degradation studies as per International Conference on Harmonization guidelines. A simple, rapid, precise, and accurate high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (LC/ESI/Q/TOF/MS/MS) method has been developed for the identification and structural characterization of stressed degradation products of ketorolac. The drug was found to degrade in hydrolytic (acidic, basic, and neutral), photolytic (acidic, basic, and neutral solution), and thermal conditions, whereas the solid form of the drug was found to be stable under photolytic conditions. The method has shown adequate separation of ketorolac tromethamine and its degradation products on a Grace Smart C-18 (250 mm × 4.6 mm i.d., 5 µm) column using 20 mM ammonium formate (pH = 3.2): acetonitrile as a mobile phase in gradient elution mode at a flow rate of 1.0 ml/min. A total of nine degradation products were identified and characterized by LC/ESI/MS/MS. The most probable mechanisms for the formation of degradation products have been proposed on the basis of a comparison of the fragmentation of the [M + H](+) ions of ketorolac and its degradation products. In silico toxicity of the drug and degradation products was investigated by using topkat and derek softwares. The method was validated in terms of specificity, linearity, accuracy, precision, and robustness as per International Conference on Harmonization guidelines.

  5. In situ degradability of elephant grass ensiled with increasing levels of pineapple agro-industrial by-product

    Directory of Open Access Journals (Sweden)

    Ana Cristina Holanda Ferreira

    2016-09-01

    Full Text Available The objective of this study was to evaluate the in situ degradability of dry matter (DM, crude protein (CP, neutral detergent fiber (NDF, acid detergent fiber (ADF, and hemicellulose of elephant grass (Pennisetumpurpureum, Schum. with increasing levels (0; 35.0; 70.0, 105.0, and 140.0 g kg-1 of dried pineapple (Ananascomosus, L. by-product (DPBP. The experimental silos consisted of plastic drums with 210 L capacity. After weighing and homogenizing the elephant grass with the DABP, the material was inserted in the silos (126 kg silage, at a density of 600 kg m-3 and compressed. After 45 days of ensilage, silos were opened and samples of the silages were collected for the trial. The study of degradability in situ was conducted using a rumen-fistulated male cattle. The animal was fed with corn silage supplemented with 1 kg concentrate daily. Five levels of addition of the by-product were tested, with three replicates and five times of incubation with an animal. The experimental design was completely randomized with split plots, in which the proportions of DPBP were the treatments (plots, the different silos were the replicates, and the incubation times were the subplots. The levels of inclusion of DPBP provided an increase (P < 0.05 in disappearance of DM and CP and in the effective degradability of DM, NDF, ADF, and hemicellulose. The dried pineapple by-product is a potential alternative to be used as additive in the ensilage of elephant grass, as it provides an increase in the rumen degradability parameters.

  6. Recent studies in microbial degradation of petroleum hydrocarbons in hypersaline environments

    Directory of Open Access Journals (Sweden)

    Babu Zhereppa Fathepure

    2014-04-01

    Full Text Available Many hypersaline environments are often contaminated with petroleum compounds. Among these, oil and natural gas production sites all over the world and hundreds of kilometers of coastlines in the more arid regions of Gulf countries are of major concern due to the extent and magnitude of contamination. Because conventional microbiological processes do not function well at elevated salinities, bioremediation of hypersaline environments can only be accomplished using high salt-tolerant microorganisms capable of degrading petroleum compounds. In the last two decades, there have been many reports on the biodegradation of hydrocarbons in moderate to high salinity environments. Numerous microorganisms belonging to the domain Bacteria and Archaea have been isolated and their phylogeny and metabolic capacity to degrade a variety of aliphatic and aromatic hydrocarbons in varying salinities have been demonstrated. This article focuses on our growing understanding of bacteria and archaea responsible for the degradation of hydrocarbons under aerobic conditions in moderate to high salinity conditions. Even though organisms belonging to various genera have been shown to degrade hydrocarbons, members of the genera Halomonas Alcanivorax, Marinobacter, Haloferax, Haloarcula, and Halobacterium dominate the published literature. Despite rapid advances in understanding microbial taxa that degrade hydrocarbons under aerobic conditions, not much is known about organisms that carry out similar processes in anaerobic conditions. Also, information on molecular mechanisms and pathways of hydrocarbon degradation in high salinity is scarce and only recently there have been a few reports describing genes, enzymes and breakdown steps for some hydrocarbons. These limited studies have clearly revealed that degradation of oxygenated and non-oxygenated hydrocarbons by halophilic and halotolerant microorganisms occur by pathways similar to those found in non-halophiles.

  7. Photooxidative degradation of beer bittering principles: product analysis with respect to lightstruck flavour formation.

    Science.gov (United States)

    Huvaere, Kevin; Sinnaeve, Bart; Van Bocxlaer, Jan; De Keukeleire, Denis

    2004-09-01

    Isohumulones, the main bittering agents in beer, are decomposed by light-induced reactions, thereby leading to radical precursors on the pathway to lightstruck flavour formation. Excited flavins, formed on visible-light irradiation, readily interact with isohumulones, as well as with reduced and oxidized derivatives thereof. From identification of both volatile and non-volatile reaction products thus formed, feasible degradation mechanisms are proposed.

  8. Radiolytic degradation of methoxychlor in methanol and monitoring of radiolytic products by HPLC and GC-MS

    Energy Technology Data Exchange (ETDEWEB)

    Butt, S.B. [Central Analytical Facility Div., Pakistan Inst. of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Riaz, M. [Chemistry Div., Pakistan Inst. of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)

    2010-07-01

    Degradation of priority organic pollutant methoxychlor in methanol solution by gamma irradiation under varied experimental conditions has been optimized. The solution of methoxychlor was air saturated before irradiation. The extent of radiolytic degradation efficiency was monitored by reversed phase HPLC-UV; two major and two minor degradation products were detected. For 5 kGy gamma radiation dose at a rate of 200 kGy h{sup -1} {>=} 95% methoxychlor was degraded. The degradation was also monitored by GC-ECD and the degradation products were identified using GC-MS after comparing their mass spectra with the NIST 98m mass spectral library. It is proposed that major degradation occurs through dechlorination, dehydrochlorination, by the detachment of methoxyphenyl from methoxychlor and by interaction of other radicals generated by the methanol radiolysis. The probable reaction schemes for the formation of products have been proposed. Most of the generated products were methoxy substituted, probably due to the availability of the methoxy radical from methanol radiolysis. The identified radiolytic products of methoxychlor and the removal efficiency have been compared with those of UV photolysis. It is observed that although the source of degradation is somewhat different, the end products or radical generated species are of similar nature. (orig.)

  9. Study of the thermal degradation of citrus seeds

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Montoya, V. [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Apdo. Postal J-55, Puebla 72570, Pue (Mexico); Instituto Nacional del Carbon, CSIC, Apartado 73, E-33080 Oviedo (Spain); Montes-Moran, M.A. [Instituto Nacional del Carbon, CSIC, Apartado 73, E-33080 Oviedo (Spain); Elizalde-Gonzalez, M.P. [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Apdo. Postal J-55, Puebla 72570, Pue (Mexico)

    2009-09-15

    The citrus seeds are one of the principal residues in the juice industry and their utilization can decrease significantly the problems of their final disposal. In this work the thermal degradation of three Mexican citrus seeds: orange (Citrus sinensis), lemon (Citrus Limon) and grapefruit (Citrus paradisi) was studied in nitrogen atmosphere. The two components (embryo and husk) of the seeds were characterized separately. The results showed that the thermal effects are very similar between the three embryos and the three husks. The embryos show higher degradability, superior content of nitrogen and higher heating value than the husks. The thermal degradation of the components of the three seeds is completed at 600 C and it is considered to be a global process derived from the decomposition of their principal components (cellulose, hemicellulose and lignin). The results suggest that mixing the three entire seeds will not lead to a severe deviation from their individual thermal behavior and that the industry could apply them for carbonization purposes. (author)

  10. Use of time-resolved fluorescence spectroscopy to evaluate diagnostic value of collagen degradation products.

    Science.gov (United States)

    Sikora, Joanna; Cyrankiewicz, Michał; Wybranowski, Tomasz; Ziomkowska, Blanka; Ośmiałowski, Borys; Obońska, Ewa; Augustyńska, Beata; Kruszewski, Stefan; Kubica, Jacek

    2015-05-01

    The concentration of collagen degradation products (CDPs) may reflect the process of left ventricular remodeling (LVR). The aim of this study was to evaluate the potential diagnostic usefulness of time-resolved fluorescence spectroscopy (TRFS) in assessment of CDPs. The preliminary experiment was designed to establish if CDPs’ characteristics might be visible by mean fluorescence lifetime (FLT) in determined conditions. The in vitro model of CDPs was prepared by conducting the hydrolysis of type III collagen. The FLT of samples was measured by the time-resolved spectrometer Life Spec II with the subnanosecond pulsed 360-nm EPLED diode. The FLTs were obtained by deconvolution analysis of the data using a multiexponential model of fluorescence decay. In order to determine the limit of traceability of CDPs, a comparison of different collagen/plasma ratio in samples was performed. The results of our study showed that the increase of added plasma to hydrolyzed collagen extended the mean FLT. Thus, the diagnosis of LVR based on measurements using TRFS is possible. However, it is important to point out the experiment was preliminary and further investigation in this field of research is crucial.

  11. Plasma fibrinogen degradation products in betel nut chewers - with and without oral submucous fibrosis

    Directory of Open Access Journals (Sweden)

    G Kiran

    2013-01-01

    Full Text Available Context: Oral submucous fibrosis (OSMF has a multifactorial etiology. Recent studies have shown that there is an increased level of fibrinogen degradation products (FDP in plasma of OSMF patients suggesting its possible role in etiopathogenesis of OSMF. Aims: To detect the presence of FDP in the plasma of betel nut chewers with and without OSMF and in normal subjects without any habits, to correlate these levels with respect to the clinical and histological grading of OSMF and whether it can be used as a nonsurgical diagnostic aid in detection of suspected OSMF cases. Materials and Methods: Study comprised of 35 cases of betel nut chewers with OSMF, 10 patients with betel nut chewing habit but having apparently normal oral mucosa, and 10 normal patients without any habits. The patients were evaluated for plasma FDP levels. Results: All the betel nut chewers with OSMF showed the presence of plasma FDP. However, controls and subjects with habit, but without OSMF did not show FDP in the plasma. Spearman′s rank correlation was used to find the association between the clinical and histological grades and it was not statistically significant (P = 0.910 and the correlation being 0.020. Conclusion: Since only those patients with OSMF have showed the presence of FDP in plasma, we suggest that our test can be utilized as a nonsurgical diagnostic aid in suspected OSMF patients.

  12. Isolation and study of Biodegradiation Potential of Phenanthrene degrading bacteria

    Directory of Open Access Journals (Sweden)

    nafise Nourieh

    2009-11-01

    Full Text Available Polycyclic Aromatic Hydrocarbons (PAHs are among of potentially hazardous chemicals for environment and cause health concern. These compounds exhibit carcinogenic and/or mutagenic properties and are listed by the United States Environmental Protection Agency (USEPA as priority pollutants. Polycyclic Aromatic Hydrocarbons are hardly degraded and therefore bioremediation is often considered as a desirable and cost effective remediation technique for soil. contaminated with them. Materials and Methods: In this research Phenanthrene (C14H10, a three-benzene ring PAHs, was selected as a PAH representative compound and two different concentrations of Phenanthrene (100mg/kg and 500mg/kg were studied. First, PAH-degrading microorganisms were separated and after adaptation and enrichment PAH-degrading bacteria were identified. Results: The results showed that removal efficiency of Phenanthrene in the samples containing pseudomonas was more than other specified bacteria. Also the most removal efficiency of Phenanthrene occurred in first 45 days of biotreatment and then decreasing trend slowed down. Other finding was that the bioremediation of the lower concentration of Phenanthrene takes shorter time compared with the higher concentration and also the comparison of Phenanthrene bioremediation by pure bacteria and Consertium indicated that, at the beginning of the process, the pace of eliminating Phenanthrene by Consertium is more than other bacteria. Conclusion: Microbial analysis, based on cinfirmation tests and analytical profile index (api 20E kit tests, showed that Pseudomonas. SPP, Bacillus, Pseudomonas aeruginosa and Acinetobacter were the bacteria, responsible for Phenanthrene degradation. Extraction was conducted by ultra sonic method and Phenanthrene concentration was measured by (HPLC.

  13. Atrazine and its degradation products in surface and ground waters in Zhangjiakou District, China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A method using the solid phase extraction (SPE) and liquid chromatography-mass spectrometry (LC-MS) to analyse atrazine and its degradation products at levels of low nanograms per liter in water has been developed. The environmental water samples were filtered and then extracted by SPE with a new sulfonation of poly(divinylbenzene-co-N- vinylpyrrolidone) sorbents MCX. HPLC/APCIMS was used for the analysis of atrazine and its degradation products, desethylatrazine (DEA), deisopropylatrazine (DIA), didealkylatrazine (DEDIA), and hydroxyatrazine (HYA). The detection limits ranged from 10-50 ng/L in water samples. Samples were collected from deep wells and a reservoir near a plant that produced atrazine. Atrazine concentration levels in most surface samples were above the limit of the China Surface Water Regulation (3 mg/L). In ground water, the levels of degradation product were more than 0.1 mg/L and 5-10 times greater than those of atrazine. The highest DEA concentration in the groundwater sample taken at the 130 m depth was 7.2 ug/L.

  14. PEGylated single-walled carbon nanotubes activate neutrophils to increase production of hypochlorous acid, the oxidant capable of degrading nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vlasova, Irina I., E-mail: irina.vlasova@yahoo.com [Research Institute for Physico-Chemical Medicine, Federal Medico-Biological Agency, Moscow (Russian Federation); Vakhrusheva, Tatyana V. [Research Institute for Physico-Chemical Medicine, Federal Medico-Biological Agency, Moscow (Russian Federation); Sokolov, Alexey V.; Kostevich, Valeria A. [Research Institute for Physico-Chemical Medicine, Federal Medico-Biological Agency, Moscow (Russian Federation); Research Institute for Experimental Medicine, Russian Academy of Medical Science, Saint Petersburg (Russian Federation); Gusev, Alexandr A.; Gusev, Sergey A. [Research Institute for Physico-Chemical Medicine, Federal Medico-Biological Agency, Moscow (Russian Federation); Melnikova, Viktoriya I. [Institute of Developmental Biology, Russian Academy of Science, Moscow (Russian Federation); Lobach, Anatolii S. [Institute of Problems of Chemical Physics, Russian Academy of Science, Chernogolovka (Russian Federation)

    2012-10-01

    Perspectives for the use of carbon nanotubes in biomedical applications depend largely on their ability to degrade in the body into products that can be easily cleared out. Carboxylated single-walled carbon nanotubes (c-SWCNTs) were shown to be degraded by oxidants generated by peroxidases in the presence of hydrogen peroxide. In the present study we demonstrated that conjugation of poly(ethylene glycol) (PEG) to c-SWCNTs does not interfere with their degradation by peroxidase/H{sub 2}O{sub 2} system or by hypochlorite. Comparison of different heme-containing proteins for their ability to degrade PEG-SWCNTs has led us to conclude that the myeloperoxidase (MPO) product hypochlorous acid (HOCl) is the major oxidant that may be responsible for biodegradation of PEG-SWCNTs in vivo. MPO is secreted mainly by neutrophils upon activation. We hypothesize that SWCNTs may enhance neutrophil activation and therefore stimulate their own biodegradation due to MPO-generated HOCl. PEG-SWCNTs at concentrations similar to those commonly used in in vivo studies were found to activate isolated human neutrophils to produce HOCl. Both PEG-SWCNTs and c-SWCNTs enhanced HOCl generation from isolated neutrophils upon serum-opsonized zymosan stimulation. Both types of nanotubes were also found to activate neutrophils in whole blood samples. Intraperitoneal injection of a low dose of PEG-SWCNTs into mice induced an increase in percentage of circulating neutrophils and activation of neutrophils and macrophages in the peritoneal cavity, suggesting the evolution of an inflammatory response. Activated neutrophils can produce high local concentrations of HOCl, thereby creating the conditions favorable for degradation of the nanotubes. -- Highlights: ► Myeloperoxidase (MPO) product hypochlorous acid is able to degrade CNTs. ► PEGylated SWCNTs stimulate isolated neutrophils to produce hypochlorous acid. ► SWCNTs are capable of activating neutrophils in blood samples. ► Activation of

  15. In vitro degradability and total gas production of biodiesel chain byproducts used as a replacement for cane sugar feed

    Directory of Open Access Journals (Sweden)

    Milenna Nunes Moreira

    2014-09-01

    Full Text Available This study aimed to determine the in vitro degradability of dry matter and the total gas production of oil seed press cake from biodiesel production (Gossypium hirsutum L., Helianthus annuus L., Ricinus communis, Moringa oleífera L. and Pinhão manso curcas L. at four different levels of replacement (0, 30, 50, and 70% for cane sugar (Saccharum officinarum RB. in ruminant feed. Inocula were prepared using the ruminal fluid of three Holstein cows, and data were collected after 48 hours of incubation. The byproducts of Moringa had the highest degradability, and castor presented the lowest values at all evaluated levels of replacement. Castor bean byproduct showed the highest total gas production, cotton showed the lowest production, and the byproduct of Moringa at the 70% level showed the best ruminal fermentation results. These results demonstrate that the use of oil seed press cake from biodiesel production (Helianthus annuus L. and Ricinus communis can replace cane sugar in ruminant feed.

  16. Degradation Study on Sulfasalazine and a Validated HPLC-UV Method for its Stability Testing.

    Science.gov (United States)

    Saini, Balraj; Bansal, Gulshan

    2014-01-01

    Sulfasalazine (SSZ) was subjected to degradation under the conditions of hydrolysis (acid, alkali, and water), oxidation (30% H2O2), dry heat, and photolysis (UV-VIS light) in accordance with the ICH guidelines. An RP-HPLC method was developed to study the degradation behavior. No degradation was noted under any condition except alkaline hydrolysis where SSZ was degraded to a single minor product. SSZ was optimally resolved from this product on an XTerra(®) RP18 column with a mobile phase composed of methanol and an ammonium acetate buffer (10 mM, pH 7.0) (48:52, v/v) delivered at a rate of 0.8 mL/min in an isocratic mode. The method was validated and found to be linear (r(2)=0.99945), precise (%RSD 2 from the nearest resolving peak, indicating the method to be selectively stability-indicating for the drug analysis. The method was applied successfully for the stability testing of the commercially available SSZ tablets that were under varied ICH-prescribed conditions. An explanation for the unusual stability of the drug when exposed to acidic hydrolysis, despite the presence of the sulfonamide linkage, is also discussed.

  17. The interactive effect of the degradation of cotton clothing and decomposition fluid production associated with decaying remains.

    Science.gov (United States)

    Ueland, Maiken; Nizio, Katie D; Forbes, Shari L; Stuart, Barbara H

    2015-10-01

    Textiles are a commonly encountered source of evidence in forensic cases. In the past, most research has been focused on how textiles affect the decomposition process while little attention has been paid to how the decomposition products interact with the textiles. While some studies have shown that the presence of remains will have an effect on the degradation of clothing associated with a decaying body, very little work has been carried out on the specific mechanisms that prevent or delay textile degradation when in contact with decomposing remains. In order to investigate the effect of decomposition fluid on textile degradation, three clothed domestic pig (Sus scrofa domesticus) carcasses were placed on a soil surface, textile specimens were collected over a period of a year and were then analysed using ATR-FTIR spectroscopy and GC-MS. Multivariate statistical analysis was used to analyse the data. Cotton specimens not associated with remains degraded markedly, whereas the samples exposed to decomposition fluids remained relatively intact over the same time frame. An investigation of the decomposition by-products found that the protein-related bands remained stable and unchanged throughout the experiment. Lipid components, on the other hand, demonstrated a significant change; this was confirmed with the use of both ATR-FTIR spectroscopy and GC-MS. Through an advanced statistical approach, information about the decomposition by-products and their characteristics was obtained. There is potential that the lipid profile in a textile specimen could be a valuable tool used in the examination of clothing located at a crime scene.

  18. Bacterial degradation of synthetic and kraft lignin by axenic and mixed culture and their metabolic products.

    Science.gov (United States)

    Chandra, Ram; Bharagava, Ram Naresh

    2013-11-01

    Pulp paper mill effluent has high pollution load due to presence of lignin and its derivatives as major colouring and polluting constituents. In this study, two lignin degrading bacteria IITRL1 and IITRSU7 were isolated and identified as Citrobacter freundii (FJ581026) and Citrobacter sp. (FJ581023), respectively. In degradation study by axenic and mixed culture, mixed bacterial culture was found more effective compared to axenic culture as it decolourized 85 and 62% of synthetic and kraft lignin whereas in axenic conditions, bacterium IITRL1 and IITRSU7 decolourized 61 and 64% synthetic and 49 and 54% kraft lignin, respectively. Further, the mixed bacterial culture also showed the removal of 71, 58% TOC; 78, 53% AOX; 70, 58% COD and 74, 58% lignin from synthetic and kraft lignin, respectively. The ligninolytic enzyme was characterized as manganese peroxidase by SDS-PAGE yielding a single band of 43 KDa. The HPLC analysis of degraded samples showed reduction as well as shifting of peaks compared to control indicating the degradation as well as transformation of compounds. Further, in GC-MS analysis of synthetic and kraft lignin degraded samples, hexadecanoic acid was found as recalcitrant compounds while 2,4,6-trichloro-phenol, 2,3,4,5-tetrachloro-phenol and pentachloro-phenol were detected as new metabolites.

  19. Degradation and metabolism of synthetic plastics and associated products by Pseudomonas sp.: capabilities and challenges.

    Science.gov (United States)

    Wilkes, R A; Aristilde, L

    2017-09-01

    Synthetic plastics, which are widely present in materials of everyday use, are ubiquitous and slowly-degrading polymers in environmental wastes. Of special interest are the capabilities of microorganisms to accelerate their degradation. Members of the metabolically diverse genus Pseudomonas are of particular interest due to their capabilities to degrade and metabolize synthetic plastics. Pseudomonas species isolated from environmental matrices have been identified to degrade polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polyethylene terephthalate, polyethylene succinate, polyethylene glycol and polyvinyl alcohol at varying degrees of efficiency. Here, we present a review of the current knowledge on the factors that control the ability of Pseudomonas sp. to process these different plastic polymers and their by-products. These factors include cell surface attachment within biofilms, catalytic enzymes involved in oxidation or hydrolysis of the plastic polymer, metabolic pathways responsible for uptake and assimilation of plastic fragments and chemical factors that are advantageous or inhibitory to the biodegradation process. We also highlight future research directions required in order to harness fully the capabilities of Pseudomonas sp. in bioremediation strategies towards eliminating plastic wastes. © 2017 The Society for Applied Microbiology.

  20. Forced degradation studies: current trends and future perspectives for protein-based therapeutics.

    Science.gov (United States)

    Chan, Christine P

    2016-07-01

    Forced degradation (FD) studies (stress testing) are an integral part of pharmaceutical product development. The design and execution of these studies require thorough planning and coordination through the various stages of development as well as post-approval commercial operations. This is particularly crucial in the case for protein-based therapeutics due to complexity of the molecular structure as well as the potential influence of the manufacturing process on product attributes. Often, FD study applications are linked to specific product development in a phase-specific and case-by-case manner with differing purposes and focus. Expert commentary: This paper summarizes some key FD approaches commonly employed in the industry and provides considerations on study design strategies and database management through the course of the product lifecycle.

  1. Sources and Input Pathways of Glyphosate and its Degradation Product AMPA

    Science.gov (United States)

    Bischofberger, S.; Hanke, I.; Wittmer, I.; Singer, H.; Stamm, C.

    2009-04-01

    Despite being the pesticide used in the largest quantities worldwide, the environmental relevance of glyphosate has been considered low for many years. Reasons for this assessment were the observations that glyphosate degrades quickly into its degradation product AMPA and that it sorbs strongly to soil particles. Hence, little losses to water bodies had been expected. Research during the last few years however contradicts this expectation. Although glyphosate is a dominant pesticide used in agriculture, recent studies on other pesticides revealed that urban sources may play a significant role for water quality. Therefore this study compares glyphosate input into streams from agricultural and urban sources. For that purpose, a catchment of an area of 25 km2 was selected. It has by about 12'000 inhabitants and about 15 % of the area is used as arable land. Four sampling sites were selected in the river system in order to reflect different urban and agricultural sources. Additionally, we sampled a combined sewer overflow, a rain sewer and the outflow of a waste water treatment plant. At each site discharge was measured continuously from March to November 2007. During 16 rain events samples were taken by automatic devices at a high temporal resolution. To analyze the concentration of glyphosate and its degradation product AMPA, the samples were derivatized with FMOC-Cl at low pH conditions and then filtrated. The solid phase extraction was conducted with Strata-X sorbent cartridge. Glyphosate and AMPA were detected with API 4000 after the chromatography with X bridge column C18. To assure the data quality, interne standards of Glyphosate and AMPA were added to every sample. The limit of detection and quantification for glyphosate and AMPA are bellow 1ng/l. We analyzed two rain events at a high resolution for all stations and several events at the outlet of the catchment. We measured high glyphosate concentration in urban and agriculture dominated catchments with up to

  2. Mixed-mode sorption of hydroxylated atrazine degradation products to sell: A mechanism for bound residue

    Science.gov (United States)

    Lerch, R.N.; Thurman, E.M.; Kruger, E.L.

    1997-01-01

    This study tested the hypothesis that sorption of hydroxylated atrazine degradation products (HADPs: hydroxyatrazine, HA; deethylhydroxyatrazine, DEHA; and deisopropylhydroxyatrazine, DIHA) to soils occurs by mixed-mode binding resulting from two simultaneous mechanisms: (1) cation exchange and (2) hydrophobic interaction. The objective was to use liquid chromatography and soil extraction experiments to show that mixed-mode binding is the mechanism controlling HADP sorption to soils and is also a mechanism for bound residue. Overall, HADP binding to solid-phase extraction (SPE) sorbents occurred in the order: cation exchange >> octadecyl (C18) >> cyanopropyl. Binding to cation exchange SPE and to a high-performance liquid chromatograph octyl (C8) column showed evidence for mixed-mode binding. Comparison of soil extracted by 0.5 M KH2P04, pH 7.5, or 25% aqueous CH3CN showed that, for HA and DIHA, cation exchange was a more important binding mechanism to soils than hydrophobic interaction. Based on differences between several extractants, the extent of HADP mixed-mode binding to soil occurred in the following order: HA > DIHA > DEHA. Mixed-mode extraction recovered 42.8% of bound atrazine residues from aged soil, and 88% of this fraction was identified as HADPs. Thus, a significant portion of bound atrazine residues in soils is sorbed by the mixed-mode binding mechanisms.

  3. HPLC determination of estradiol, its degradation product, and preservatives in new topical formulation Estrogel HBF.

    Science.gov (United States)

    Nováková, Lucie; Solich, Petr; Matysová, Ludmila; Sícha, Jan

    2004-07-01

    This paper deals with the development of a novel method for simultaneous determination of estradiol, its degradation product estrone, and two preservatives, methylparaben and propylparaben, in the topical preparation Estradiol HBF. After optimization of the analytical conditions the method was validated and applied in studies of the stability of the topical preparation Estrogel HBF. Separation of all these compounds was performed on a Supelco Discovery C18 (250 mm x 3.0 mm, 5 microm) analytical column. A mixture of acetonitrile, methanol, and water (23:24:53 v/ v) was chosen as mobile phase. UV absorbance at 225 nm was used for detection and quantitation of analytes. The total analysis time was less than 12 min at a flow rate of 0.9 mL min(-1). All the compounds were isolated from the topical gel by simple extraction with an acetonitrile solution of hydrocortisone, as internal standard, and using sonication and centrifugation thereafter. The supernatant was injected directly on to the analytical column. The recovery of the procedure was from 96.9 to 100.4%. Validation of method according international guidelines was successfully performed.

  4. Diagnostic implication of fibrin degradation products and D-dimer in aortic dissection

    Science.gov (United States)

    Dong, Jian; Duan, Xianli; Feng, Rui; Zhao, Zhiqing; Feng, Xiang; Lu, Qingsheng; Jing, Qing; Zhou, Jian; Bao, Junmin; Jing, Zaiping

    2017-01-01

    Fibrin degradation products (FDP) and D-dimer have been considered to be involved in many vascular diseases. In this study we aimed to explore the diagnostic implication of FDP and D-dimer in aortic dissection patients. 202 aortic dissection patients were collected as the case group, 150 patients with other cardiovascular diseases, including myocardial infarction (MI, n = 45), pulmonary infarction (n = 51) and abdominal aortic aneurysm (n = 54) were collected as non-dissection group, and 27 healthy people were in the blank control group. The FDP and D-dimer levels were detected with immune nephelometry. Logist regression analysis was performed to evaluate the influence of FDP and D-dimer for the aortic dissection patients. ROC curve was used to determine the diagnostic value of FDP and D-dimer. The FDP and D-dimer levels were significantly higher in aortic dissection patients than in non-dissection patients and the healthy controls. FDP and D-dimer were both the risk factors for patients with aortic dissection. From the ROC analysis, diagnostic value of FDP and D-dimer were not high to distinguish aortic dissection patients from the non-dissection patients. However FDP and D-dimer could be valuable diagnostic marker to differentiate aortic dissection patients and healthy controls with both AUC 0.863. PMID:28262748

  5. Stress degradation studies on citicoline sodium and development of a validated stability-indicating HPLC assay

    Directory of Open Access Journals (Sweden)

    Jimmi A Patel

    2011-01-01

    Full Text Available Aim: High performance liquid chromatography presents a useful aspect for the development of stability indicating assays. Objective of the current study was to establish inherent stability of citicoline sodium through stress studies under a variety of international conference on harmonization recommended test conditions and to develop a stability-indicating assay. Materials and Methods: Thermal stability studies were performed in a hot air oven (Hicon and photo stability studies were carried out under the sunlight. The chromatographic separations were carried out on a reverse phase phenomenox C18 (250 mm΄4.6 mm i.d., particle size 5 ΅m column. The chromatographic method was fine tuned using the sample generated from forced degradation studies. Mobile phase consists of mixture of buffer (potassium dihydrogen orthophosphate, tetra butyl ammonium, triethyl amine; pH 5.5; 0.002M and methanol (95:5, v/v. Results: Good resolution between the peaks corresponds to degradation products and the analyte was achieved on 5 ΅, 250 mm΄4.6 mm i.d., C18 column (Luna, phenomenox, USA. The method was validated for accuracy, precision, linearity, range, and selectivity. Conclusion: The study shows that citicoline sodium is a labile molecule in acid, oxidative, and alkali conditions. It is stable to light and dry heat. A stability-indicating method was developed and is recommended for analysis of the drug and degradation products in stability samples.

  6. Thermal degradation reaction mechanism of xylose: A DFT study

    Science.gov (United States)

    Huang, Jinbao; He, Chao; Wu, Longqin; Tong, Hong

    2016-08-01

    The thermal degradation reaction mechanism of xylose as hemicellulose model compound was investigated by using density functional theory methods M062X with the 6-31++G(d,p) basis set. Eight possible pyrolytic reaction pathways were proposed and the standard kinetic and thermodynamic parameters in all reaction pathways were calculated at different temperatures. In reaction pathway (1), xylose is first transformed into acyclic containing-carbonyl isomer, and then the isomer further decomposes through four possible pyrolysis pathways (1-1)-(1-4). Pathways (2) and (3) depict an immediate ring-opening process through the simultaneous breaking of C-O and C-C bonds. Pathways (4)-(7) describe the pyrolysis processes of various anhydro-xyloses through a direct ring-opening process. Pathway (8) gives the evolutionary process of pyranones. The calculation results show that reaction pathways (1), (2) and (5) are the major reaction channels and reaction pathways (3), (4), and (6)-(8) are the competitive reaction channels in pyrolysis of xylose. The major products of xylose pyrolysis are low molecular products such as 2-furaldehyde, glycolaldehyde, acetaldehyde, methylglyoxal and acetone, and the main competitive products are formaldehyde, formic acid, acetic acid, CO2, CH4, acetol, pyranone, and so on.

  7. Module Degradation Mechanisms Studied by a Multi-Scale Approach

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Steve; Al-Jassim, Mowafak; Hacke, Peter; Harvey, Steven P.; Jiang, Chun-Sheng; Gerber, Andreas; Guthrey, Harvey; Moutinho, Helio; Albin, David; To, Bobby; Tynan, Jerry; Moseley, John; Aguiar, Jeffery; Xiao, Chuanxiao; Waddle, John; Nardone, Marco

    2016-11-21

    A key pathway to meeting the Department of Energy SunShot 2020 goals is to reduce financing costs by improving investor confidence through improved photovoltaic (PV) module reliability. A comprehensive approach to further understand and improve PV reliability includes characterization techniques and modeling from module to atomic scale. Imaging techniques, which include photoluminescence, electroluminescence, and lock-in thermography, are used to locate localized defects responsible for module degradation. Small area samples containing such defects are prepared using coring techniques and are then suitable and available for microscopic study and specific defect modeling and analysis.

  8. THE CHALLENGE OF PD PATIENTS: GLUCOSE AND GLUCOSE DEGRADATION PRODUCTS IN PD SOLUTION

    Directory of Open Access Journals (Sweden)

    Yong-Lim Kim

    2012-06-01

    Full Text Available The main osmotic agent found in the peritoneal dialysis (PD solution is glucose. It has been of a wide use for great crystalloid osmotic power at a low concentration, simple metabolism, and excellent safety. On the other hand, anywhere between 60 to 80% of the glucose in the PD solution is absorbed - a 100 to 300 mg of daily glucose absorption. Once into the systemic circulation, glucose can be a cause for metabolic complications including obesity. Indeed, the diabetiform change observed in the peritoneal membrane in the long-term PD patients is believed attributable to the high-concentration glucose in the PD solution. The glucose absorbed from peritoneal cavity raises the risk of ‘glucose toxicity’, leading to insulin resistance and beta cell failure. Clinical similarity can be found in postprandial hyperglycemia, which is known to be associated with oxidative stress, endothelial dysfunction, NF-κb, and inflammation, affecting myocardial blood flow. Moreover, it is a proven independent risk factor of coronary artery disease in patients with type 2 diabetes, particularly of female gender. Though speculative yet, glucose toxicity might explain a higher mortality of PD patients after the first year compared with those on hemodialysis (more so in female, advanced-age patients with diabetes. Also included in the picture are glucose degradation products (GDPs generated along the course of heat sterilization or storage of the PD solution. They have been shown to induce apoptosis of peritoneal mesothelial cells, renal tubular epithelial cells, and endothelial cells, while spurring production of TGF-β and VEGF and facilitating epithelial mesenchymal transition. GDPs provide a stronger reactivity than glucose in the formation of AGEs, a known cause for microvascular complications and arteriosclerosis. Unfortunately, clinical studies using a low-GDP PD solution have provided mixed results on the residual renal function, peritonitis, peritoneal

  9. THE FTIR STUDIES OF PHOTO-OXIDATIVE DEGRADATION OF POLYPROPYLENE

    Institute of Scientific and Technical Information of China (English)

    WEN Zaiqing; HU Xingzhou; SHEN Deyan

    1988-01-01

    The photo-oxidative degradation process of polypropylene film containing iron ions was investigated via FTIR and absorbance substraction technique. It is shown that the iron ions play an important role in the decomposition of hydroperoxide and the increase of the degradation rate of polypropylene film. Theamorphous region of PP film undergoes degradation prior to the crystalline one.

  10. A novel UV degradation product of Ebastine: isolation and characterization using Q-TOF, NMR, IR and computational chemistry.

    Science.gov (United States)

    Rapolu, Ravi; Pandey, Avadhesh Kumar; Raju, Ch Krishnam; Ghosh, Kaushik; Srinivas, Kolupula; Awasthi, Atul; Navalgund, Sameer G; Surendranath, Koduru V

    2015-03-25

    Forced degradation of Ebastine (1-(4-(1,1-dimethylethyl)phenyl)-4-(4-(diphenylmethoxy) piperidin-1-yl)butan-1-one) drug substance in ultraviolet light condition resulted into an unknown significant degradation product. This degradation product was analyzed using a newly developed reverse-phase HPLC, where it was eluted at 2.73 relative retention time to Ebastine peak. UV degradation product was isolated from reaction mass using preparative HPLC and its structure was elucidated using high resolution MS, multidimensional NMR and FTIR spectroscopic techniques. UV degradation product has been characterized as 2-(4-(benzhydryloxy)piperidin-1-yl)-1-(4-(tert-butyl)phenyl)-2-methylcyclopropanol. (1)H and (13)C NMR chemical shift values were generated using computational chemistry for possible two diastereomers (7R10S and 7R10R) and later 7R10R was confirmed (and its enantiomer) as final structure given it showed close agreement with experimental NMR data. Formation of UV degradation product as a recemic mixture was further verified by computational chemistry evaluation, chiral HPLC and polarimetery. To best of our knowledge, this is a novel degradation product which is not discussed at any form of publication yet.

  11. Fracturing Fluid (Guar Polymer Gel Degradation Study by using Oxidative and Enzyme Breaker

    Directory of Open Access Journals (Sweden)

    Aung Kyaw

    2012-06-01

    Full Text Available Oxidative and enzyme breakers are used in this research project with the main objective to study on the degradation pattern of fracturing fluid (i.e., guar polymer gel as a function of time, temperature and breaker concentration itself. The fracturing fluid used in hydraulic fracturing or frac pack contain a chemical breakers to reduce the viscosity of the fluid intermingled with the proppant. Chemical breakers reduce viscosity of the guar polymer by cleaving the polymer into small-molecular-weight fragments. The reduction of viscosity will facilitate the flow-back of residual polymer providing rapid recovery of polymer from proppant pack. Ineffective breakers or misapplication of breakers can result in screen-outs or flow-back of viscous fluids both of which can significantly decrease the well productivity. Breaker activity of low to medium temperature range oxidative and enzyme breaker systems was evaluated. ViCon NF an oxidative breaker (Halliburton product and GBW 12- CD an enzyme breaker (BJ Services product were used in this research project with the main objective to study on the degradation pattern of fracturing fluid (guar polymer gel as a function of (time, temperature and breaker concentration itself. This study provides focuses on the way to mix the fracturing fluid, compositions of the fracturing fluid and how to conduct the crosslink and break test. Crosslink test indicate the optimum cross-linker concentration to produce good crosslink gel and the break test gave the characteristic of the gel during degradation process and also the break time. Besides relying on the laboratory experiment, information obtained from research on SPE and US Pattern papers were used to make a comparison study on oxidative and enzyme breakers properties. Degradation pattern observed from the break test showed that reduction in gel viscosity depends on time, temperature and breaker concentration. Observations from experiment also revealed that small

  12. Tryptophan degradation in women with breast cancer: a pilot study

    Directory of Open Access Journals (Sweden)

    Schubert Christine M

    2011-05-01

    Full Text Available Abstract Background Altered tryptophan metabolism and indoleamine 2,3-dioxygenase activity are linked to cancer development and progression. In addition, these biological factors have been associated with the development and severity of neuropsychiatric syndromes, including major depressive disorder. However, this biological mechanism associated with both poor disease outcomes and adverse neuropsychiatric symptoms has received little attention in women with breast cancer. Therefore, a pilot study was undertaken to compare levels of tryptophan and other proteins involved in tryptophan degradation in women with breast cancer to women without cancer, and secondarily, to examine levels in women with breast caner over the course of chemotherapy. Findings Blood samples were collected from women with a recent diagnosis of breast cancer (n = 33 before their first cycle of chemotherapy and after their last cycle of chemotherapy. The comparison group (n = 24 provided a blood sample prior to breast biopsy. Plasma concentrations of tryptophan, kynurenine, and tyrosine were determined. The kynurenine to tryptophan ratio (KYN/TRP was used to estimate indoleamine 2,3-dioxygenase activity. On average, the women with breast cancer had lower levels of tryptophan, elevated levels of kynurenine and tyrosine and an increased KYN/TRP ratio compared to women without breast cancer. There was a statistically significant difference between the two groups in the KYN/TRP ratio (p = 0.036, which remained elevated in women with breast cancer throughout the treatment trajectory. Conclusions The findings of this pilot study suggest that increased tryptophan degradation may occur in women with early-stage breast cancer. Given the multifactorial consequences of increased tryptophan degradation in cancer outcomes and neuropsychiatric symptom manifestation, this biological mechanism deserves broader attention in women with breast cancer.

  13. Newly identified degradation products of ceftiofur and cephapirin impact the analytical approch for quantitative analysis of kidney

    NARCIS (Netherlands)

    Berendsen, B.J.A.; Essers, M.L.; Mulder, P.P.J.; Bruchem, van G.D.; Lommen, A.; Overbeek, van W.M.; Stolker, A.A.M.

    2009-01-01

    This paper describes our research on the degradation of ceftiofur and cephapirin at physiological temperatures in kidney extract and in alkaline and acidic solution, conditions that regularly occur during sample preparation. Degradation products were identified using LC¿ToF/MS, NMR and microbiologic

  14. Natural and enhanced anaerobic degradation of 1,1,1-trichloroethane and its degradation products in the subsurface – A critical review

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Durant, Neal D.; Hansen, Maria Heisterberg;

    2011-01-01

    1,1,1-Trichloroethane (TCA) in groundwater is susceptible to a variety of natural degradation mechanisms. Evidence of intrinsic decay of TCA in aquifers is commonly observed; however, TCA remains a persistent pollutant at many sites and some of the daughter products that accumulate from intrinsic...

  15. Organotin persistence in contaminated marine sediments and porewaters: In situ degradation study using species-specific stable isotopic tracers

    Energy Technology Data Exchange (ETDEWEB)

    Furdek, Martina; Mikac, Nevenka [Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, Zagreb (Croatia); Bueno, Maite; Tessier, Emmanuel; Cavalheiro, Joana [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux, CNRS UMR 5254, Université de Pau et des Pays de l’Adour, Hélioparc Pau Pyrénées, 2, Av. P. Angot, 64053 Pau Cedex 9 (France); Monperrus, Mathilde, E-mail: mathilde.monperrus@univ-pau.fr [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux, CNRS UMR 5254, Université de Pau et des Pays de l’Adour, Hélioparc Pau Pyrénées, 2, Av. P. Angot, 64053 Pau Cedex 9 (France)

    2016-04-15

    Highlights: • Limiting step in OTC degradation in sediments is their desorption into porewater. • TBT persistence in contaminated sediments increases in sediments rich in organic matter. • DBT does not accumulate in sediments as degradation product of TBT. • TBT and DBT degradation in porewaters occurs with half-lives from 2.9 to 9.2 days. • PhTs degradation is slower than BuTs degradation in oxic porewaters. - Abstract: This paper provides a comprehensive study of the persistence of butyltins and phenyltins in contaminated marine sediments and presents the first data on their degradation potentials in porewaters. The study’s aim was to explain the different degradation efficiencies of organotin compounds (OTC) in contaminated sediments. The transformation processes of OTC in sediments and porewaters were investigated in a field experiment using species-specific, isotopically enriched organotin tracers. Sediment characteristics (organic carbon content and grain size) were determined to elucidate their influence on the degradation processes. The results of this study strongly suggest that a limiting step in OTC degradation in marine sediments is their desorption into porewaters because their degradation in porewaters occurs notably fast with half-lives of 9.2 days for tributyltin (TBT) in oxic porewaters and 2.9 ± 0.1 and 9.1 ± 0.9 days for dibutyltin (DBT) in oxic and anoxic porewaters, respectively. By controlling the desorption process, organic matter influences the TBT degradation efficiency and consequently defines its persistence in contaminated sediments, which thus increases in sediments rich in organic matter.

  16. Manipulating Protein Degradability in the Rumen to Support Higher Ruminant Production

    Directory of Open Access Journals (Sweden)

    Budi Haryanto

    2014-09-01

    Full Text Available Dietary protein is digested to a certain extent in the rumen causing decreases its potency as source of amino acids for the animal. Dietary protein should mostly reach the intestines where the protein digestion takes place and absorption occurs in the form of intact amino acids and subsequently becomes nutrient deposition in muscles or milk. The higher muscle or milk protein synthesis, the higher the protein in the products of animal, as long as energy for the metabolism is available. Strategies of feeding rumen degradable versus undegradable protein in ruminant have become a research interest for decades. Technologies of dietary protein protection to reduce its degradability in the rumen by heating, chelating or coating have been developed.

  17. AepA of Pectobacterium is not involved in the regulation of extracellular plant cell wall degrading enzymes production.

    Science.gov (United States)

    Kõiv, Viia; Andresen, Liis; Mäe, Andres

    2010-06-01

    Plant cell wall degrading enzymes (PCWDE) are the major virulence determinants in phytopathogenic Pectobacterium, and their production is controlled by many regulatory factors. In this study, we focus on the role of the AepA protein, which was previously described to be a global regulator of PCWDE production in Pectobacterium carotovorum (Murata et al. in Mol Plant Microbe Interact 4:239-246, 1991). Our results show that neither inactivation nor overexpression of aepA affects PCWDE production in either Pectobacterium atrosepticum SCRI1043 or Pectobacterium carotovorum subsp. carotovorum SCC3193. The previously published observation based on the overexpression of aepA could be explained by the presence of the adjacent regulatory rsmB gene in the constructs used. Our database searches indicated that AepA belongs to the YtcJ subfamily of amidohydrolases. YtcJ-like amidohydrolases are present in bacteria, archaea, plants and some fungi. Although AepA has 28% identity with the formamide deformylase NfdA in Arthrobacter pascens F164, AepA was unable to catalyze the degradation of NdfA-specific N-substituted formamides. We conclude that AepA is a putative aminohydrolase not involved in regulation of PCWDE production.

  18. [Function of nitric oxide in initiating production of lignin degrading peroxidases by Phanerochaete chrysosporium].

    Science.gov (United States)

    Zheng, Yaotong; Qiu, Ailian; Li, Wenyan; Zheng, Feng; Zhang, Li; Shi, Yaqing; Zheng, Gang; Zou, Yanqiong

    2013-03-04

    By analyzing the function and mechanism of nitric oxide in initiating producing lignin peroxidases by phanerochaete chrysosporium, we studied the regulation mechanism triggering the secondary metabolism of white-rot fungi. Mutant (pcR5305) and wild-type (pc530) strains of phanerochaete chrysosporium were respectively cultured under both the conditions of nitrogen limitation and nitrogen sufficiency. To compare their lignin peroxidases (LiP)-production and nitric oxide(NO)-production kinetics and their different influences on producing LiP after the NO donor Sodium Nitroprusside (SNP) and scavenger cPTIO were respectively added to the nitrogen limitation or sufficiency culture medium to show the function and mechanism of nitric oxide in initiating production of lignin peroxidases by white-rot fungi. Both strains produced nitric oxide (NO) under the two opposite nutritional conditions, but the levels of NO produced were related with the type of strain and the nutritional conditions. Strain pc530 produced NO requiring nutrition depletion and producing of NO was strongly delayed and reduced when it was cultured under nitrogen sufficiency condition. On the contrary, pcR5305 did not require nitrogen depletion to trigger and the levels of NO were higher than that of pc530. The results indicate that LiP content had positive correlation with NO value except the occurrence time of LiP peak value was later than that of NO. The ability of producing LiP was promoted after the NO donor SNP added, but SNP affected more on pc530 than pcR5305 in promoting producing LiP. 15mM cPTIO would greatly repress producing LiP, but could not completely restrain the synthesis of LiP for both strains. By producing NO, Phanerochaete chrysosporium triggers LiP synthesis. However, the evidences do not indicate that NO participates or effect directly in LiP synthesis. It is more likely that NO is reacting as an upstream signal molecule. Besides NO, there are other signal molecules that have a

  19. Biosurfactant production by Pseudomonas fluorescens growing on molasses and its application in phenol degradation

    Science.gov (United States)

    Suryantia, Venty; Marliyana, Soerya Dewi; Wulandari, Astri

    2015-12-01

    A molasses based medium for the biosurfactant production by Pseudomonas fluorescens was developed, where the effect of pre-treated of molasses and medium composition were evaluated. Biosurfactant production was followed by measuring optical density (OD), surface tension and emulsifying index (E24) over 12 days of fermentation. The optimum condition for the biosurfactant production was obtained when a medium containing of 8 g/L nutrient broth, 5 g/L NaCl, 1 g/L NH4NO3 and 5% v/v pre-treated molasses with centrifugation was used as media with 3 days of fermentation. The biosurfactant was identified as a rhamnolipid type biosurfactant which had critical micelle concentration (CMC) value of 801 mg/L and was able to reduce the surface tension of the water from 80 mN/m to 51 mN/m. The biosurfactants had water in oil (w/o) emulsion type. Biosurfactant was able to emulsify various hydrocarbons, which were able to decrase the interfacial tension about 50-75% when benzyl chloride, anisaldehyde and palm oil were used as immiscible compounds. The biosurfactant exhibited the E24 value of about 50% and the stable emulsion was reached up to 30 days when lubricant was used as an immiscible compound. Up to 68% of phenol was degraded in the presence of biosurfactant within 15 days, whereas only 56% of phenol was degraded in the absence of biosurfactant. Overall, the results exhibited that molasses are recommended for the rhamnolipids production which possessed good surface-active properties and had potential application in the enhancement of phenol degradation.

  20. Physicochemical properties and radiolytic degradation studies on tri-iso-amyl phosphate (TiAP)

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasulu, B.; Sivaraman, Nagarajan [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India). Homi Bhabha National Inst.; Suresh, A.; Rajeswari, S.; Ramanathan, N.; Antony, M.P.; Joseph, M. [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India). Chemistry Group

    2017-06-01

    The solvent composed of tri-iso-amyl phosphate (TiAP) in n-dodecane (n-DD) is regarded as a promising candidate for reprocessing of spent fuel. In this context, the radiolytic degradation of a solution of TiAP in n-dodecane was investigated by irradiating the solvent to various absorbed dose levels of γ-radiation. The neat extractant or a solution of extractant in n-dodecane was irradiated in the presence of nitric acid. Physicochemical properties such as density, viscosity and interfacial tension (IFT) were measured for unirradiated and irradiated solutions. The extent of degradation was determined by measuring the variation in extraction behavior of U(VI) and Pu(IV) with irradiated solvent systems. Uranium and plutonium retention with irradiated solvents was also measured. The distribution ratio of uranium and plutonium increased with increase in absorbed dose. Effect of alpha degradation was studied by plutonium retention as a function of time using 1.1 M TiAP/n-DD. Laser desorption/ionization mass spectrometric technique was employed to identify the possible radiolytic degradation products. Similar studies were also carried out with tri-n-butyl phosphate (TBP) based solvent system under identical experimental conditions and the results are compared.

  1. A study of the UV and VUV degradation of FEP

    Science.gov (United States)

    George, Graeme A.; Hill, David J. T.; Odonnell, James H.; Pomery, Peter J.; Rasoul, Firas A.

    1993-01-01

    UV and VUV degradation of fluorinated ethylene propylene (FEP) copolymer was studied using electron spin resonance (ESR) spectroscopy, x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The ESR study revealed the formation of a terminal polymer radical. The stability of this radical was investigated under different environments. An XPS study of FEP film exposed to VUV and atomic oxygen showed that oxidation takes place on the polymer surface. The study revealed also that the percentage of CF2 in the polymer surface decreased with exposure time and the percentage of CF, CF3, and carbon attached to oxygen increased. SEM micrographs of FEP film exposed to VUV and atomic oxygen identified a rough surface with undulations similar to sand dunes.

  2. Why do forest products become less available?A pan-tropical comparison of drivers of forest-resource degradation

    Science.gov (United States)

    Hermans-Neumann, Kathleen; Gerstner, Katharina; Geijzendorffer, Ilse R.; Herold, Martin; Seppelt, Ralf; Wunder, Sven

    2016-12-01

    Forest products provide an important source of income and wellbeing for rural smallholder communities across the tropics. Although tropical forest products frequently become over-exploited, only few studies explicitly address the dynamics of degradation in response to socio-economic drivers. Our study addresses this gap by analyzing the factors driving changes in tropical forest products in the perception of rural smallholder communities. Using the poverty and environment network global dataset, we studied recently perceived trends of forest product availability considering firewood, charcoal, timber, food, medicine, forage and other forest products. We looked at a pan-tropical sample of 233 villages with forest access. Our results show that 90% of the villages experienced declining availability of forest resources over the last five years according to the informants. Timber and fuelwood together with forest foods were featured as the most strongly affected, though with marked differences across continents. In contrast, availability of at least one main forest product was perceived to increase in only 39% of the villages. Furthermore, the growing local use of forest resources is seen as the main culprit for the decline. In villages with both growing forest resource use and immigration—vividly illustrating demographic pressures—the strongest forest resources degradation was observed. Conversely, villages with little or no population growth and a decreased use of forest resources were most likely to see significant forest-resource increases. Further, villages are less likely to perceive resource declines when local communities own a significant share of forest area. Our results thus suggest that perceived resource declines have only exceptionally triggered adaptations in local resource-use and management patterns that would effectively deal with scarcity. Hence, at the margin this supports neo-Malthusian over neo-Boserupian explanations of local resource

  3. The role of metabolism in the toxicity of 2,4,6-trinitrotoluene and its degradation products to the aquatic amphipod Hyalella azteca.

    Science.gov (United States)

    Sims, Jerre G; Steevens, Jeffery A

    2008-05-01

    Toxicological data on the effects of the explosive, 2,4,6-trinitrotoluene (TNT), and its degradation products suggests an unpredictable toxicological response in aquatic organisms. Several studies suggest TNT becomes more toxic as it degrades while others suggest TNT becomes less toxic. This study focused on the toxicity of TNT and several degradation products as well as the role of oxidative metabolism in the toxicity of TNT. The aquatic invertebrate Hyalella azteca was used to evaluate the toxicity of TNT and four of its degradation products. The most reduced degradation product, 2,4-diamino, 6-nitrotoluene (2,4-DANT) was the most toxic to H. azteca. However, 2,4-DANT was only a minor metabolite in H. azteca. The influence of metabolism on the toxicokinetics of TNT was assessed indirectly through the use of a CYP450 inducer and inhibitor. Treatment of organisms with beta-napthoflavone (BNF), a CYP450 inducer, increased the toxicity of TNT and increased the rate of elimination and metabolism of TNT. Similar to BNF, organisms treated with clotrimazole (CTZ), a CYP450 inhibitor, resulted in increased toxicity and TNT metabolism. It is likely the ability to metabolize or bioactivate TNT to a more reactive intermediate plays a significant role in the sensitivity of organisms to TNT.

  4. Structural analysis and biological toxicity of Aflatoxin B1 and B2 degradation products following detoxification by Ocimum basilicum and Cassia fistula aqueous extracts

    Directory of Open Access Journals (Sweden)

    Wajiha Iram

    2016-07-01

    Full Text Available This study showed the comparison between Ocimum basilicum and Cassia fistula (leaves & branch aqueous extracts for their ability to detoxify of aflatoxin B1 and B2 (AFB1; 100 µg L-1 and AFB2; 50 µg L-1 by In Vitro assays and decontamination studies. Results indicated that O. basilicum leaves extract was found to be highly significant (P < 0.05 in degrading AFB1 and AFB2 i.e. 90.4% and 88.6% respectively. However O. basilicum branch, C. fistula leaves and branch extracts proved to be less efficient in degrading these aflatoxins, under optimized conditions i.e., pH 8, temperature 30˚C and incubation period of 72h. Moreover the antifungal activity of these plants extracts were also tested. The findings depicted that O. basilicum leaves extract showed maximum growth inhibition of aflatoxigenic isolates i.e., 82 – 87% as compared to other tested plants extracts. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that nine degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that O. basilicum leaves extract can be used as an effective tool for the detoxification of aflatoxins.

  5. Exposure to airborne isocyanates and other thermal degradation products at polyurethane-processing workplaces.

    Science.gov (United States)

    Henriks-Eckerman, Maj-Len; Välimaa, Jarmo; Rosenberg, Christina; Peltonen, Kimmo; Engström, Kerstin

    2002-10-01

    The thermal degradation products of polyurethanes (PURs) and exposure to isocyanates were studied by stationary and personal measurements in five different occupational environments. Isocyanates were collected on glass fibre filters impregnated with 1-(2-methoxyphenyl)piperazine (2MP) and in impingers containing n-dibutylamine (DBA) in toluene. connected to a glass fibre postfilter. The derivatives formed were analysed by liquid chromatography: 2MP derivatives with UV and electrochemical detection and DBA derivatives with mass spectrometric detection. The release of aldehydes and other volatile organic compounds into the air was also studied. In a comparison of the two sampling methods, the 2MP method yielded about 20% lower concentrations for 4,4'-methylenediphenyl diisocyanate (MDI) than did the DBA method. In car repair shops, the median concentration of diisocyanates (given as NCO groups) in the breathing zone was 1.1 microg NCO m(-3) during grinding and 0.3 microg NCO m(-3) during welding, with highest concentrations of 1.7 and 16 pg NCO m(-3), respectively. High concentrations of MDI, up to 25 and 19 microg NCO m(-3), respectively, were also measured in the breathing zone during welding of district heating pipes and turning of a PUR-coated metal cylinder. During installation of PUR-coated floor covering, small amounts of aliphatic diisocyanates were detected in the air. A small-molecular monoisocyanate, methyl isocyanate, and isocyanic acid were detected only during welding and turning operations. The diisocyanate concentrations were in general higher near the emission source than in the workers' breathing zone. A sampling strategy to evaluate the risk of exposure to isocyanates is presented.

  6. Synergistic effect of co-digestion to enhance anaerobic degradation of catering waste and orange peel for biogas production.

    Science.gov (United States)

    Anjum, Muzammil; Khalid, Azeem; Qadeer, Samia; Miandad, Rashid

    2017-09-01

    Catering waste and orange peel were co-digested using an anaerobic digestion process. Orange peel is difficult to degrade anaerobically due to the presence of antimicrobial agents such as limonene. The present study aimed to examine the feasibility of anaerobic co-digestion of catering waste with orange peel to provide the optimum nutrient balance with reduced inhibitory effects of orange peel. Batch experiments were conducted using catering waste as a potential substrate mixed in varying ratios (20-50%) with orange peel. Similar ratios were followed using green vegetable waste as co-substrate. The results showed that the highest organic matter degradation (49%) was achieved with co-digestion of catering waste and orange peel at a 50% mixing ratio (CF4). Similarly, the soluble chemical oxygen demand (sCOD) was increased by 51% and reached its maximum value (9040 mg l(-1)) due to conversion of organic matter from insoluble to soluble form. Biogas production was increased by 1.5 times in CF4 where accumulative biogas was 89.61 m(3) t(-1)substrate compared with 57.35 m(3) t(-1)substrate in the control after 80 days. The main reason behind the improved biogas production and degradation is the dilution of inhibitory factors (limonene), with subsequent provision of balanced nutrients in the co-digestion system. The tCOD of the final digestate was decreased by 79.9% in CF4, which was quite high as compared with 68.3% for the control. Overall, this study revealed that orange peel waste is a highly feasible co-substrate for anaerobic digestion with catering waste for enhanced biogas production.

  7. Pressurized-water reactor internals aging degradation study. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Luk, K.H. [Oak Ridge National Lab., TN (United States)

    1993-09-01

    This report documents the results of a Phase I study on the effects of aging degradations on pr internals. Primary stressers for internals an generated by the primary coolant flow in the they include unsteady hydrodynamic forces and pump-generated pressure pulsations. Other stressors are applied loads, manufacturing processes, impurities in the coolant and exposures to fast neutron fluxes. A survey of reported aging-related failure information indicates that fatigue, stress corrosion cracking (SCC) and mechanical wear are the three major aging-related degradation mechanisms for PWR internals. Significant reported failures include thermal shield flow-induced vibration problems, SCC in guide tube support pins and core support structure bolts, fatigue-induced core baffle water-jet impingement problems and excess wear in flux thimbles. Many of the reported problems have been resolved by accepted engineering practices. Uncertainties remain in the assessment of long-term neutron irradiation effects and environmental factors in high-cycle fatigue failures. Reactor internals are examined by visual inspections and the technique is access limited. Improved inspection methods, especially one with an early failure detection capability, can enhance the safety and efficiency of reactor operations.

  8. Inhibition of ethanol-producing yeast and bacteria by degradation products produced during pre-treatment of biomass

    DEFF Research Database (Denmark)

    Klinke, H.B.; Thomsen, A.B.; Ahring, Birgitte Kiær

    2004-01-01

    An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are available to render the carbohydrates in lignocellulose accessible...... degradation, phenol monomers from lignin degradation are important co-factors in hydrolysate inhibition, and inhibitory effects of these aromatic compounds on different ethanol producing microorganisms is reviewed. The furans and phenols generally inhibited growth and ethanol production rate (Q...

  9. Simultaneous HPLC determination of ketoprofen and its degradation products in the presence of preservatives in pharmaceuticals.

    Science.gov (United States)

    Dvorák, J; Hájková, R; Matysová, L; Nováková, L; Koupparis, M A; Solich, P

    2004-11-15

    A novel and quick high-performance liquid chromatography (HPLC) method with UV spectrophotometric detection was developed and validated for the determination of five compounds in topical gel. The described method is suitable for simultaneous determination of active component ketoprofen, two preservatives methylparaben and propylparaben and two degradation products of ketoprofen--3-acetylbenzophenone and 2-(3-carboxyphenyl) propionic acid--in a topical cream after long-term stability tests using ethylparaben as an internal standard. The chromatographic separation was performed on a 5microm Supelco Discovery C18 column (125mm x 4mm i.d., Sigma-Aldrich); the optimal mobile phase for separation of ketoprofen, methylparaben, propylparaben, degradation products 3-acetylbenzophenone and 2-(3-carboxyphenyl) propionic acid and ethylparaben as internal standard consists of a mixture of acetonitril, water and phosphate buffer pH 3.5 (40:58:2, v/v/v). At a flow rate of 1.0ml min(-1) and detection at 233nm, the total time of analysis was less than 10min. The method was applied for routine analysis (batch analysis and stability tests) of these compounds in topical pharmaceutical product.

  10. [Effects of nitrogen and phosphorous fertilization on community structure and productivity of degraded alpine meadows in northern Tibet, China].

    Science.gov (United States)

    Zong, Ning; Shi, Pei-li; Niu, Ben; Jiang, Jing; Song, Ming-hua; Zhang, Xian-zhou; He, Yong-tao

    2014-12-01

    Abstract: Fertilization is an effective management measure for recovery of degraded grasslands. To better understand the effects of fertilization on community structure and productivity of lightly and severely degraded alpine meadows, we conducted a fertilization experiment in northern Tibet since 2008. The treatments were addition of nitrogen (N) alone (50 kg N x hm(-2) x a(-1), LN; 100 kg N x hm(-2) x a(-1), HN) or addition of both phosphorus (P) and N (50 kg N x hm(-2) x a(-1) +50 kg P x hm(-2) x a(-1), LN+P; 100 kg N x hm(-2) x a(-1) +50 kg P x hm(-2) x a(-1), HN+P) in each of the two types of degraded alpine meadows. N addition alone significantly affected plant community coverage or productivity in neither the slightly nor the severely degraded alpine meadow, while addition of both N and P significantly increased plant community coverage, aboveground and below- ground biomass of the alpine meadows. This suggested that productivity of this alpine meadow is co-limited by N and P. HN and HN+P significantly decreased species richness and evenness in the lightly degraded grassland, indicating that HN was not beneficial for the lightly degraded grassland to maintain species diversity and community stability. N addition significantly reduced the root to shoot ratio in the severely degraded meadow. In the lightly degraded meadow, N addition alone, especially with a high amount (HN) , enhanced the importance values (IV) and biomass of grasses, while fertilization with both N and P increased those of sedges. In the severely degraded meadow, fertilization had little effect on IV of grasses or sedges, but improved biomass of forbs. The results suggested that LN+P could be employed in recovery of lightly degraded alpine meadows, but other management measures such as fencing and reseeding may be needed for recovery of severely degraded alpine meadows.

  11. Influence of fermentation on glucosinolates and glucobrassicin degradation products in sauerkraut.

    Science.gov (United States)

    Palani, Kalpana; Harbaum-Piayda, Britta; Meske, Diana; Keppler, Julia Katharina; Bockelmann, Wilhelm; Heller, Knut J; Schwarz, Karin

    2016-01-01

    A systematic investigation was carried out on the influence of fermentation on glucosinolates and their degradation products from fresh raw cabbage, throughout fermentation at 20 °C and storage at 4 °C. Glucosinolates were degraded dramatically between Day 2 and 5 of fermentation and by Day 7 there was no detectable amount of glucosinolates left. Fermentation led to formation of potential bioactive compounds ascorbigen (13.0 μmol/100 g FW) and indole-3-carbinol (4.52 μmol/100g FW) with their higher concentrations from Day 5 to Day 9. However, during storage indole-3-carbinol slowly degraded to 0.68 μmol/100 g FW, while ascorbigen was relatively stable from Week 4 until Week 8 at 6.78 μmol/100 g FW. In contrast, the content of indole-3-acetonitrile decreased rapidly during fermentation from 3.6 to 0.14 μmol/100 g FW. The results imply a maximum of health beneficial compounds after fermentation (7-9 days) in contrast to raw cabbage or stored sauerkraut.

  12. A validated stability-indicating LC method for acetazolamide in the presence of degradation products and its process-related impurities.

    Science.gov (United States)

    Srinivasu, Prabha; Subbarao, Devarakonda V; Vegesna, Raju V K; Sudhakar Babu, K

    2010-05-01

    The objective of the current study was to develop a validated, specific and stability-indicating reverse phase liquid chromatographic method for the quantitative determination of acetazolamide and its related substances. The determination was done for an active pharmaceutical ingredient, its pharmaceutical dosage form in the presence of degradation products, and its process-related impurities. The drug was subjected to stress conditions of hydrolysis (acid and base), oxidation, photolysis and thermal degradation as per International Conference on Harmonization (ICH) prescribed stress conditions to show the stability-indicating power of the method. Significant degradation was observed during acid and base hydrolysis, and the major degradant was identified by LC-MS, FTIR and (1)H/(13)C NMR spectral analysis. The chromatographic conditions were optimized using an impurity-spiked solution and the generated samples were used for forced degradation studies. In the developed HPLC method, the resolution between acetazolamide and, its process-related impurities (namely imp-1, imp-2, imp-3, imp-4 and its degradation products) was found to be greater than 2. The chromatographic separation was achieved on a C18, 250mmx4.6mm, 5microm column. The LC method employed a linear gradient elution, and the detection wavelength was set at 254nm. The stress samples were assayed against a qualified reference standard and the mass balance was found to be close to 99.6%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.

  13. Development of chromatographic methods for analysis of sulfamethoxazole, trimethoprim, their degradation products and preservatives in syrup

    OpenAIRE

    Perović, Ivana; Malenović, Anđelija; Vemić, Ana; Kostić, Nađa; Ivanović, Darko

    2014-01-01

    In this paper the experimental conditions for optimal reversed-phase liquid chromatographic (RP-HPLC) determination of sulfamethoxazole, trimethoprim and preservatives, as well as degradation products of sulfamethoxazole and trimethoprim in syrup were defined. The determination of active compounds and preservatives was carried out on Zorbax Eclipse XDB-C18, 150 mm × 4.6 mm, 5 μm particle size column, mobile phase flow rate was 1.5 mL min-1, and detection at 235 nm for the active compounds and...

  14. A theoretical and experimental study of the thermal degradation of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Groenli, Morten G.

    1996-12-31

    This thesis relates to the thermal degradation of biomass covering a theoretical and experimental study in two parts. In the first part, there is presented an experimental and modeling work on the pyrolysis of biomass under regimes controlled by chemical kinetics, and the second part presents an experimental and modeling work on the pyrolysis of biomass under regimes controlled by heat and mass transfer. Five different celluloses, and hemicellulose and lignin isolated from birch and spruce have been studied by thermogravimetry. The thermo grams of wood species revealed different weight loss characteristics which can be attributed to their different chemical composition. The kinetic analysis gave activation energies between 210 and 280 kJ/mole for all the celluloses, and a model of independent parallel reactions was successfully used to describe the thermal degradation. In the second part of the thesis there is presented experimental and modeling work on the pyrolysis of biomass under regimes controlled by heat and mass transfer. The effect of heating conditions on the product yields distribution and reacted fraction was investigated. The experiments show that heat flux alters the pyrolysis products as well as the intra particle temperatures to the greatest extent. A comprehensive mathematical model which can simulate drying and pyrolysis of moist wood is presented. The simulation of thermal degradation and heat transport processes agreed well with experimental results. 198 refs., 139 figs., 68 abs.

  15. Structural Elucidation and Toxicity Assessment of Degraded Products of Aflatoxin B1 and B2 by Aqueous Extracts of Trachyspermum ammi.

    Science.gov (United States)

    Iram, Wajiha; Anjum, Tehmina; Iqbal, Mazhar; Ghaffar, Abdul; Abbas, Mateen

    2016-01-01

    In this study aqueous extract of seeds and leaves of Trachyspermum ammi were evaluated for their ability to detoxify aflatoxin B1 and B2 (AFB1; 100 μg L(-1) and AFB2; 50 μg L(-1)) by in vitro and in vivo assays. Results indicated that T. ammi seeds extract was found to be significant (P < 0.05) in degrading AFB1 and AFB2 i.e., 92.8 and 91.9% respectively. However, T. ammi leaves extract proved to be less efficient in degrading these aflatoxins, under optimized conditions i.e., pH 8, temperature 30°C and incubation period of 72 h. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that eight degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that T. ammi seeds extract can be used as an effective tool for the detoxification of aflatoxins.

  16. Structural elucidation and toxicity assessment of degraded products of aflatoxin B1 and B2 by aqueous extracts of Trachyspermum ammi

    Directory of Open Access Journals (Sweden)

    Wajiha eIram

    2016-03-01

    Full Text Available In this study aqueous extract of seeds and leaves of Trachyspermum ammi were evaluated for their ability to detoxify aflatoxin B1 and B2 (AFB1; 100 µg L-1 and AFB2; 50 µg L-1 by In Vitro and In Vivo assays. Results indicated that T. ammi seeds extract was found to be highly significant (P < 0.05 in degrading AFB1 and AFB2 i.e. 92.8% and 91.9% respectively. However T. ammi leaves extract proved to be less efficient in degrading these aflatoxins, under optimized conditions i.e., pH 8, temperature 30˚C and incubation period of 72h. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that eight degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that T. ammi seeds extract can be used as an effective tool for the detoxification of aflatoxins.

  17. Study on the Degradation of Polylactide Microsphere In Vitro

    Institute of Scientific and Technical Information of China (English)

    HeYing; WeiShuli

    2001-01-01

    This report concentrated on the rules and mechanism of the degradation of polylactide and the microspheres. The rate of degradation was assessed with five methods: observation of microsphere surface morphology by SEM, determination of the weight loss of the microspheres, determination of the molecular mass of the polymers by GPC, determination of pH and determination of the contents of lactic acid by UV spectrophotometry. The degradation of polylactide microspheres showed two-phase characteristics. At the early stage of the degradation, the high molecular mass polymers were cleaved into lower molecular mass fractions and at the late stage, there was a period of erosion and weight loss of the microspheres. The degradation was much slower for polymers with a higher molecular mass. The polylactide degradation showed good regularity.

  18. Photocatalytic degradation of a widely used insecticide Thiamethoxam in aqueous suspension of TiO{sub 2}: Adsorption, kinetics, product analysis and toxicity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Mir, Niyaz A.; Khan, A. [Department of Chemistry, Aligarh Muslim University, Aligarh-202002, UP (India); Muneer, M., E-mail: readermuneer@gmail.com [Department of Chemistry, Aligarh Muslim University, Aligarh-202002, UP (India); Vijayalakhsmi, S. [SAIF, CRNTS, IIT Bombay, Powai, 400076, Mumbai (India)

    2013-08-01

    This paper deals with the study of photocatalyzed degradation of an insecticide, Thiamethoxam in aqueous suspension of TiO{sub 2}. The adsorption of Thiamethoxam on TiO{sub 2} surface under dark conditions was also investigated in order to find out equilibrium adsorption constant. The degradation kinetics was studied using spectrophotometric method under various conditions such as substrate concentration, type of catalyst, catalyst dosage, pH, and in the presence of electron acceptors such as hydrogen peroxide, potassium bromate, and ammonium persulphate under continuous purging of atmospheric oxygen, and the degradation rates were found to be strongly influenced by these parameters. The results manifested that the photocatalysis of Thiamethoxam follows pseudo-first-order kinetics. The toxicity assessments of the irradiated samples were carried out using human erythrocytes as a model system under in vitro conditions. GC–MS study showed the formation of several intermediate products which were characterised based on their molecular mass and mass fragmentation pattern. A probable mechanism for the formation of various products formed during the photocatalytic process of Thiamethoxam was also proposed. Highlights: • TiO{sub 2} P25 is a more efficient photocatalyst than UV100 and PC500 for degradation of Thiamethoxam. • Low H{sub 2}O{sub 2} dosages enhance degradation whereas overdose retards it. • Toxicity of Thiamethoxam decreases with the increase in irradiation time. • Eight intermediate products have been identified using GC–MS analysis technique.

  19. Chemical Composition, In vitro Gas Production, Ruminal Fermentation and Degradation Patterns of Diets by Grazing Steers in Native Range of North Mexico

    Science.gov (United States)

    Murillo, M.; Herrera, E.; Carrete, F. O.; Ruiz, O.; Serrato, J. S.

    2012-01-01

    The objective of the study was to quantify annual and seasonal differences in the chemical composition, in vitro gas production, in situ degradability and ruminal fermentation of grazing steers’ diets. Diet samples were collected with four esophageal cannulated steers (350±3 kg BW); and four ruminally cannulated heifers (342±1.5 kg BW) were used to study the dry matter degradation and fermentation in rumen. Data were analyzed with repeated measurements split plot design. The crude protein, in vitro dry matter digestibility and metabolizable energy were higher during the first year of trial and in the summer (p<0.01). The values of calcium, phosphorus, magnesium, zinc and copper were higher in summer (p<0.05). The gas produced by the soluble and insoluble fractions, as well as the constant rate of gas production were greater in summer and fall (p<0.01). The ammonia nitrogen (NH3N) and total volatile fatty acids concentrations in rumen, the soluble and degradable fractions, the constant rate of degradation and the effective degradability of DM and NDF were affected by year (p<0.05) and season (p<0.01). Our study provides new and useful knowledge for the formulation of protein, energetic and mineral supplements that grazing cattle need to improve their productive and reproductive performance. PMID:25049495

  20. Chemical Composition, In vitro Gas Production, Ruminal Fermentation and Degradation Patterns of Diets by Grazing Steers in Native Range of North Mexico.

    Science.gov (United States)

    Murillo, M; Herrera, E; Carrete, F O; Ruiz, O; Serrato, J S

    2012-10-01

    The objective of the study was to quantify annual and seasonal differences in the chemical composition, in vitro gas production, in situ degradability and ruminal fermentation of grazing steers' diets. Diet samples were collected with four esophageal cannulated steers (350±3 kg BW); and four ruminally cannulated heifers (342±1.5 kg BW) were used to study the dry matter degradation and fermentation in rumen. Data were analyzed with repeated measurements split plot design. The crude protein, in vitro dry matter digestibility and metabolizable energy were higher during the first year of trial and in the summer (p<0.01). The values of calcium, phosphorus, magnesium, zinc and copper were higher in summer (p<0.05). The gas produced by the soluble and insoluble fractions, as well as the constant rate of gas production were greater in summer and fall (p<0.01). The ammonia nitrogen (NH3N) and total volatile fatty acids concentrations in rumen, the soluble and degradable fractions, the constant rate of degradation and the effective degradability of DM and NDF were affected by year (p<0.05) and season (p<0.01). Our study provides new and useful knowledge for the formulation of protein, energetic and mineral supplements that grazing cattle need to improve their productive and reproductive performance.

  1. Forced degradation studies, and effect of surfactants and titanium dioxide on the photostability of paliperidone by HPLC.

    Science.gov (United States)

    Marothu, V K; Nellutla, A; Gorrepati, M; Majeti, S; Mamidala, S K

    2015-07-01

    Forced degradation study of paliperidone under hydrolytic, oxidative, thermal and photolytic stress conditions was conducted using HPLC. The drug was found to be labile under hydrolytic, oxidative and photolytic stress conditions; whereas, it was stable under dry heat stress conditions. Effect of anionic, cationic and non-ionic surfactants applied to the concentration exceeding critical micellar concentration on the photostability of paliperidone was also studied by exposing the samples to sunlight for 72h. Major degradation of the drug was found in presence of cationic and non-ionic surfactants. Effect of titanium dioxide on the photo-degradation of paliperidone in solution state was also studied and it was found that 53% of the drug was degraded after 72h of exposure to sunlight. A common degradation peak was observed in oxidative and TiO2 photocatalysed samples. This peak may be due to the generation of N-oxide of paliperidone. The same degradation peak was also observed in all other photostability samples. Chromatographic separation of drug and its degradation products was achieved on an Alltima C8 (250mm×4.6mm, 5μm) analytical column, using a mobile phase consisting of acetonitrile-ammonium acetate buffer with 0.2% triethylamine (pH 3.5; 20mM) (60:40, v/v) at a flow rate of 1mL/min. Quantification was performed with UV detection at 280nm. The method was validated as per ICH guidelines.

  2. The effects of the antibiotics ampicillin, florfenicol, sulfamethazine, and tylosin on biogas production and their degradation efficiency during anaerobic digestion.

    Science.gov (United States)

    Mitchell, Shannon M; Ullman, Jeffrey L; Teel, Amy L; Watts, Richard J; Frear, Craig

    2013-12-01

    The impacts of four common animal husbandry antibiotics (ampicillin, florfenicol, sulfamethazine, and tylosin) on anaerobic digestion (AD) treatment efficiency and the potential for antibiotic degradation during digestion were evaluated. Sulfamethazine and ampicillin exhibited no impact on total biogas production up to 280 and 350 mg/L, respectively, although ampicillin inhibited biogas production rates during early stages of AD. Tylosin reduced biogas production by 10-38% between 130 and 913 mg/L. Florfenicol reduced biogas by ≈ 5%, 40% and 75% at 6.4, 36 and 210 mg/L, respectively. These antibiotic concentrations are higher than commonly seen for mixed feedlot manure, so impacts on full scale AD should be minimal. Antibiotic degradation products were found, confirming AD effectively degraded ampicillin, florfenicol, and tylosin, although some products were persistent throughout the process. Contamination of AD solid and liquid effluents with sulfamethazine and antibiotic transformation products from florfenicol and tylosin could present an environmental concern. Published by Elsevier Ltd.

  3. Degradation of fluoroquinolone antibiotics by ferrate(VI): Effects of water constituents and oxidized products.

    Science.gov (United States)

    Feng, Mingbao; Wang, Xinghao; Chen, Jing; Qu, Ruijuan; Sui, Yunxia; Cizmas, Leslie; Wang, Zunyao; Sharma, Virender K

    2016-10-15

    The degradation of five fluoroquinolone (FQ) antibiotics (flumequine (FLU), enrofloxacin (ENR), norfloxacin (NOR), ofloxacin (OFL) and marbofloxacin (MAR)) by ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) was examined to demonstrate the potential of this iron-based chemical oxidant to treat antibiotics in water. Experiments were conducted at different molar ratios of Fe(VI) to FQs at pH 7.0. All FQs, except FLU, were degraded within 2 min at [Fe(VI)]:[FQ] ≤ 20.0. Multiple additions of Fe(VI) improved the degradation efficiency, and provided greater degradation than a single addition of Fe(VI). The effects of anions, cations, and humic acid (HA), usually present in source waters and wastewaters, on the removal of FLU were investigated. Anions (Cl(-), SO4(2-), NO3(-), and HCO3(-)) and monovalent cations (Na(+) and K(+)) had no influence on the removal of FLU. However, multivalent cations (Ca(2+), Mg(2+), Cu(2+), and Fe(3+)) in water decreased the efficiency of FLU removal by Fe(VI). An increase in the ionic strength of the solution, and the presence of HA in the water, also decreased the percentage of FLU removed by Fe(VI). Experiments on the removal of selected FQs, present as co-existing antibiotics in pure water, river water, synthetic water and wastewater, were also conducted to demonstrate the practical application of Fe(VI) to remove the antibiotics during water treatment. The seventeen oxidized products (OPs) of FLU were identified using solid phase extraction-liquid chromatography-high-resolution mass spectrometry. The reaction pathways are proposed, and are theoretically confirmed by molecular orbital calculations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. A PRELIMINARY STUDY AND FIRST REPORT ON CAFFEINE DEGRADING BACTERIA ISOLATED FROM THE SOILS OF CHITTOOR AND VELLORE

    Directory of Open Access Journals (Sweden)

    Sharan Siddharth

    2012-03-01

    Full Text Available An attempt on basic study of the caffeine degrading organism and screening of potential ‘caffeinase’ producing bacteria has been studied and reported. Caffeine is present in soft drinks, coffee plants, tea leaves, and kola nuts and is used extensively in human consumption. Various health and environmental demerits makes it significant to reduce the levels of caffeine into a much less harmful compound, which can be done biologically using specific microorganisms. The enzyme responsible for caffeine degradation plays a major role and hence needs to be studied for caffeinase isolation and improvement of available caffeine products. Isolation of such microorganisms and their study of extent of caffeine degradation would prove to be helpful in generating an economic and safer method of caffeine removal in food products and coffee left over which could be less harmful to human health and the environment.

  5. Improved production of raw starch degrading enzyme by Aspergillus oryzae F-30 using methyl glucoside sesqui-stearate.

    Science.gov (United States)

    Sun, Hai-Yan; Wang, Lu; Liu, Jian-Wen; Peng, Ming

    2009-10-01

    The effect of methyl glucoside sesqui-stearate (MGS) on the production of raw starch degrading enzyme (RSDE) by Aspergillus oryzae F-30 was studied in this paper. The activity of RSDE formed by Aspergillus oryzae F-30 was enhanced dramatically by the addition of MGS to the medium. As a result, with the addition of 1.5 g MGS in 1 L basal medium, RSDE activity and productivity were 107 U mL(-1) and 1.49 U mL(-1) h(-1), 4.3-fold and 7.1-fold greater than the values obtained in the basal medium, respectively. The effect of MGS on the synthesis of RSDE by Aspergillus oryzae F-30 was also studied on a molecular level. It was observed that the regulation of RSDE synthesis in Aspergillus oryzae F-30 occurs at both transcriptional and translational level and the enzyme synthesis was provoked by the addition of MGS at transcriptional level.

  6. AC impedance study of degradation of porous nickel battery electrodes

    Science.gov (United States)

    Lenhart, Stephen J.; Macdonald, D. D.; Pound, B. G.

    1987-01-01

    AC impedance spectra of porous nickel battery electrodes were recorded periodically during charge/discharge cycling in concentrated KOH solution at various temperatures. A transmission line model (TLM) was adopted to represent the impedance of the porous electrodes, and various model parameters were adjusted in a curve fitting routine to reproduce the experimental impedances. Degradation processes were deduced from changes in model parameters with electrode cycling time. In developing the TLM, impedance spectra of planar (nonporous) electrodes were used to represent the pore wall and backing plate interfacial impedances. These data were measured over a range of potentials and temperatures, and an equivalent circuit model was adopted to represent the planar electrode data. Cyclic voltammetry was used to study the characteristics of the oxygen evolution reaction on planar nickel electrodes during charging, since oxygen evolution can affect battery electrode charging efficiency and ultimately electrode cycle life if the overpotential for oxygen evolution is sufficiently low.

  7. Mass spectrometric identification and toxicity assessment of degraded products of aflatoxin B1 and B2 by Corymbia citriodora aqueous extracts

    Science.gov (United States)

    Iram, Wajiha; Anjum, Tehmina; Iqbal, Mazhar; Ghaffar, Abdul; Abbas, Mateen

    2015-01-01

    This study explores the detoxification potential of Corymbia citriodora plant extracts against aflatoxin B1 and B2 (AFB1; 100 μg L−1 and AFB2; 50 μg L−1) in In vitro and In vivo assays. Detoxification was qualitatively and quantitatively analyzed by TLC and HPLC, respectively. The study was carried out by using different parameters of optimal temperature, pH and incubation time period. Results indicated that C. citriodora leaf extract(s) more effectively degrade AFB1 and AFB2 i.e. 95.21% and 92.95% respectively than C. citriodora branch extract, under optimized conditions. The structural elucidation of degraded toxin products was done by LCMS/MS analysis. Ten degraded products of AFB1 and AFB2 and their fragmentation pathways were proposed based on molecular formulas and MS/MS spectra. Toxicity of these degraded products was significantly reduced as compared to that of parent compounds because of the removal of double bond in the terminal furan ring. The biological toxicity of degraded toxin was further analyzed by brine shrimps bioassay, which showed that only 17.5% mortality in larvae was recorded as compared to untreated toxin where 92.5% mortality was observed after 96hr of incubation. Therefore, our finding suggests that C. citriodora leaf extract can be used as an effective tool for the detoxification of aflatoxins. PMID:26423838

  8. Molecular identification of the isolated diesel degrading bacteria and optimization studies

    Directory of Open Access Journals (Sweden)

    Janani Prathiba G

    2014-08-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Diesel, a refinery product of crude oil constitutes a major source of pollution in our environment. Poor solubility in water and the higher content in sediments make diesel a potential water pollutant. Bioremediation of contaminated aquatic and soil environments has arisen as an effective technology, with a range of advantages compared to more traditional methods. A total of 9 bacteria were isolated from three petroleum contaminated soil samples and isolate 3 of sample 1 showed maximum degradation potential of diesel in both primary and secondary screening tests. Hence, it was subjected for 16srDNA study and sequence alignment by BLASTN identified the isolate as Pseudomonas aeruginosa strain KEB24. The reaction conditions for efficient diesel degradation by the isolate were optimized.

  9. A degradation study of cefepime hydrochloride in solutions under various stress conditions by TLC-densitometry.

    Science.gov (United States)

    Dąbrowska, Monika; Starek, Małgorzata; Krzek, Jan; Papp, Elżbieta; Król, Piotr

    2015-03-01

    A rapid, accurate and sensitive thin-layer chromatography (TLC) method with densitometric detection has been developed and validated for the determination of cefepime in pharmaceuticals. Chromatographic separation was achieved on a silica gel TLC F254 plates with a mobile phase consisting of ethanol-2-propanol-glacial acetic acid 99.5%-water (4:4:1:3, v/v). Densitometric detection was carried out at wavelength of 266 nm in reflectance/absorbance mode. The validation of the method was found to be satisfactory with high accuracy (from 99.24 to 101.37%) and precision (RSD from 0.06 to 0.36%). Additionally, the stability of cefepime in solution was investigated, including the effect of pH, temperature and incubation time. Favorable retention parameters (Rf , Rs, α) were obtained under the developed conditions, which guaranteed good separation of the studied components. The degradation process of cefepime hydrochloride was described by kinetic and thermodynamic parameters (k, t0.1 , t0.5 and Ea ). Moreover, the chemical properties of degradation products were characterized by the Rf values, absorption spectra, HPLC-MS/MS and TLC-densitometry analysis. As the method could effectively separate the active substance from its main degradation product (1-methylpyrrolidine), it can be employed as a method to indicate the stability of this drug. Copyright © 2014 John Wiley & Sons, Ltd.

  10. Stress degradation studies on varenicline tartrate and development of a validated stability-indicating HPLC method.

    Science.gov (United States)

    Pujeri, Sudhakar S; Khader, Addagadde M A; Seetharamappa, Jaldappagari

    2012-01-01

    A simple, rapid and stability-indicating reversed-phase liquid chromatographic method was developed for the assay of varenicline tartrate (VRT) in the presence of its degradation products generated from forced decomposition studies. The HPLC separation was achieved on a C18 Inertsil column (250 mm × 4.6 mm i.d. particle size is 5 μm) employing a mobile phase consisting of ammonium acetate buffer containing trifluoroacetic acid (0.02M; pH 4) and acetonitrile in gradient program mode with a flow rate of 1.0 mL min(-1). The UV detector was operated at 237 nm while column temperature was maintained at 40 °C. The developed method was validated as per ICH guidelines with respect to specificity, linearity, precision, accuracy, robustness and limit of quantification. The method was found to be simple, specific, precise and accurate. Selectivity of the proposed method was validated by subjecting the stock solution of VRT to acidic, basic, photolysis, oxidative and thermal degradation. The calibration curve was found to be linear in the concentration range of 0.1-192 μg mL(-1) (R(2) = 0.9994). The peaks of degradation products did not interfere with that of pure VRT. The utility of the developed method was examined by analyzing the tablets containing VRT. The results of analysis were subjected to statistical analysis.

  11. Degradation products of mangiferin by gamma irradiation with inhibitory effects on NO production.

    Science.gov (United States)

    Jo, Cheorun; Yoon, Kyung Young; Jang, Eun Jin; Kim, Tae Hoon

    2016-10-01

    The xanthone glucoside mangiferin (1) was converted by γ-irradiation into three new compounds, mangiferdiol (2), mangiferinol (3), and isomangiferinol (4). The new compound 2 containing two hydroxymethyl groups instead of a ketone moiety exhibited significantly improved inhibitory activity against nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with IC50 value 47.1 ± 1.7 μM, compared to the mother mangiferin.

  12. Production of keratinolytic enzyme by an indigenous feather-degrading strain Bacillus cereus Wu2.

    Science.gov (United States)

    Lo, Wei-Hsun; Too, Jui-Rze; Wu, Jane-Yii

    2012-12-01

    A novel feather-degrading microorganism was isolated from a poultry farm in Taiwan, and was identified Bacillus cereus Wu2 according to 16S rRNA sequencing. The isolated strain produces keratinolytic enzyme using chicken feather as the sole carbon and nitrogen source. The experimental results indicated that the extra carbon sources (glucose, fructose, starch, sucrose, or lactose) could act as a catabolite repressor to the enzyme secretion or keratinolytic activity when keratinous substrates were employed as protein sources. However, addition of 2 g/L of NH(4)Cl to the feather medium increased the enzyme production. The optimum temperature and initial pH for enzyme production were 30°C and 7.0, respectively. The maximum yield of the enzyme was 1.75 kU/mL in the optimal chicken feather medium; this value was about 17-fold higher than the yield in the basal hair medium. The B. cereus Wu2 possessed disulfide reductase activity along with keratinolytic activity. The amino acid contents of feathers degradated by B. cereus Wu2 were higher, especially for lysine, methionine and threonine which were nutritionally essential amino acids and usually deficient in the feather meal. Thus, B. cereus Wu2 could be not only used to enhance the nutritional value of feather meal but is also a potential bioinoculant in agricultural environments.

  13. Tetrabromobisphenol-A, hexabromocyclododecane and its degradation products in UK human milk: relationship to external exposure.

    Science.gov (United States)

    Abdallah, Mohamed Abou-Elwafa; Harrad, Stuart

    2011-02-01

    Tetrabromobisphenol-A (TBBP-A), hexabromocyclododecane (HBCD) and its degradation products were determined in 34 human milk samples from Birmingham, UK. TBBP-A was detected in 36% of samples (average=0.06 ng g(-1) lw), with HBCDs detected in all samples (average ΣHBCDs=5.95 ng g(-1) lw). α-HBCD comprised 62-95% ΣHBCDs while β- and γ-HBCD constituted 2-18% and 3-33% respectively. Enantioselective enrichment of (-)-α-HBCD (average enantiomer fraction=0.29) was observed indicating potential enantioselectivity associated with HBCD absorption, metabolism and/or excretion. The degradation products pentabromocyclododecenes (average=0.04 ng g(-1) lw; n=9) and tetrabromocyclododecadienes (average=0.15 ng g(-1) lw; n=25) were detected for the first time in human tissues. Average exposures of a nursing infant to ΣHBCDs and TBBP-A (35 and 1 ng kg(-1) bw day(-1) respectively) via breast milk exceeded upper-bound dietary intakes of both UK adults and toddlers. Using a simple pharmacokinetic model, intakes of UK adults via inhalation, diet and dust ingestion were converted to predicted body burdens. Predictions compared well with those observed for HBCDs but observed body burdens of TBBP-A exceeded predictions. This may indicate the human half-life of TBBP-A is greater than observed previously, that intakes may be underestimated, or that concentrations reported here reflect recent elevated episodic exposure.

  14. Uptake of 8:2 perfluoroalkyl phosphate diester and its degradation products by carrot and lettuce from compost-amended soil.

    Science.gov (United States)

    Bizkarguenaga, E; Zabaleta, I; Prieto, A; Fernández, L A; Zuloaga, O

    2016-06-01

    The present work studied the uptake of 8:2 perfluoroalkyl phosphate diester (diPAP) by two different crops (lettuce and carrot) and two different amended soils. Firstly, the possible degradation of 8:2 diPAP in the absence of crop was studied and 8:2 monoPAP (monophosphate), 8:2 FTCA (saturated fluorotelomer carboxylate), 8:2 FTUCA (unsaturated fluorotelomer carboxylate), 7:3 FTCA (saturated fluorotelomer carboxylate), PFHpA (perfluoroheptanoic acid), PFHxA (perfluorohexanoic acid) and PFOA (perfluorooctanoic acid) were detected. In the presence of crops, different degradation products were detected in the soil and, while PFNA (perfluorononanoic acid), PFHpA, PFHxA, PFPeA (perfluoropentacoic acid), PFBA (perfluorobutanoic acid), 7:3 FTCA and PFOA were determined in the cultivation media when carrot was grown, PFOA was the only degradation product detected in the case of lettuce experiments. Regarding the uptake in carrot, all the degradation products except 7:3 FTCA were translocated from the soil to the carrot. Carrot core, peel and leaves bioconcentration factors, BCFs, were determined for 8:2 diPAP and its degradation products. Values lower than method detection limits for core and low BCFs in peel (0.025-0.042) and leaves (0.028-0.049) were achieved for 8:2 diPAP. Regarding to the degradation products, the higher their water solubility, the higher the plant translocation. In this sense, the lower the carbon chain length of PFCAs, the higher the BCFs determined (PFBA > PFHxA > PFHpA > PFOA > PFNA). In general, lower total BCFs were achieved when the total organic carbon of the soils increased. For lettuce experiments, 8:2 diPAP (0.04-0.18) and PFOA (0.28-1.57) were only determined in lettuce heart. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. The degradation products of aniline in the solutions with ozone and kinetic investigations.

    Science.gov (United States)

    Turhan, Kadir; Uzman, Suheyla

    2007-10-01

    Aromatic compounds are extensively used in several industries and can cause pollution in water sources. This work aims at examining the degradability of aniline in aqueous solutions by ozone-induced cleavage, and at determining the kinetics of the cited cleavage reactions. Aniline was prepared in four different concentrations and the flow rate of ozone supplied to each solution was selected. Aniline solutions were ozonated at low and high pH, so as to compare both molecular and hydroxyl free radical mechanisms, respectively. The main identified aromatic by-products were nitrobenzene and azobenzene when the experiment was carried out at acidic pH. Formation of nitrobenzene, azobenzene, azoxybenzene and 2-pyridine carboxylic acid (picolinic acid) was observed when the ozonization was carried out at basic pH. All the aromatic by-products found were less toxic than the raw materials. The pseudo-first-order constants in aniline concentrations were calculated.

  16. Ensiling Characteristics and the In situ Nutrient Degradability of a By-product Feed-based Silage

    Science.gov (United States)

    Kim, Y. I.; Oh, Y. K.; Park, K. K.; Kwak, W. S.

    2014-01-01

    This study was conducted to evaluate the ensiling characteristics and the in situ degradability of a by-product feed (BF)-based silage. Before ensilation, the BF-based mixture was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial inoculant on a wet basis and ensiled for up to 4 weeks. The BF-based silage contained on average 39.3% moisture, 13.4% crude protein (CP), and 52.2% neutral detergent fiber (NDF), 49% total digestible nutrient, and 37.8% physically effective NDF1.18 on a dry matter (DM) basis. Ensiling the BF-based silage for up to 4 weeks affected (p<0.01) the chemical composition to a small extent, increased (p<0.05) the lactic acid and NH3-N content, and decreased (p<0.05) both the total bacterial and lactic acid bacterial counts from 109 to 108 cfu/g when compared to that before ensiling. These parameters indicated that the silage was fermented and stored well during the 4-week ensiling period. Compared with rice or ryegrass straws, the BF-based silage had a higher (p<0.05) water-soluble and filterable fraction, a lower insoluble degradable DM and CP fraction (p<0.05), a lower digestible NDF (p<0.05) fraction, a higher (p<0.05) DM and CP disappearance and degradability rate, and a lower (p<0.05) NDF disappearance and degradability rate. These results indicated that cheap, good-quality BF-based roughage could be produced by ensiling SMS, RPB, rice bran, and a minimal amount of straw. PMID:25049944

  17. Experimental and Theoretical Studies on Alkaline Degradation of Cellulose and its Impact on the Sorption of Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Loon, L.R. van; Glaus, M.A

    1998-08-01

    For more than ten years, cellulose degradation has been regarded as an important process which can adversely effect the sorption of radionuclides on cement in a radioactive waste repository. However, so far, it was not possible to quantify this effect. This study reports new experimental data on alkaline degradation of cellulose, together with a re-evaluation of old literature data. For the first time now, it becomes possible to quantitatively estimate the potential role of cellulose degradation in performance assessment studies. In the first part of this study, a literature overview of other studies on alkaline degradation of cellulose is given, together with a general discussion on the effect of organic ligands on the sorption of radionuclides. Further, an overview of the important mechanisms of alkaline degradation of cellulose and some kinetic aspects of the main reactions taking place is presented. The relevance of the processes for performance assessment is explained in detail. The discussion forms the starting-point for a detailed experimental program for evaluating the role of alkaline degradation of cellulose in performance assessment. In the second part, experimental studies on alkaline degradation are presented. Different cellulosic materials were degraded in an artificial cement pore water, representing the first stage of cement degradation. The most important degradation products ({alpha}- and {beta}-isosaccharinic acid) were characterised and the results compared with other studies. Kinetic parameters for the main reactions were measured and discussed. A good agreement was found between the measured values and values extrapolated from the literature. The solubility of the sparingly soluble Ca-salt of {alpha}-isosaccharinic acid (ISA) was studied as well as the interaction of ISA with cement. Sorption of ISA on cement can keep the ISA concentration in the pore water of a repository at a low level. The effect of pure ISA and degradation products on the

  18. Elucidation of stress-induced degradation products of mangiferin: Method development and validation.

    Science.gov (United States)

    Khurana, Rajneet Kaur; Kaur, Satvinder; Kaur, Jasleen; Singh, Bhupinder

    2017-01-15

    The degradation behavior of mangiferin, under various ICH Q1A(R2) recommended stress conditions, was studied using an isocratic elution with mobile phase (pH 2.4), composed of acetonitrile and 1% orthophosphoric acid (12:88 v/v) at a flow rate of 1.0 mL/min, with λmax 262 nm. It was suitably adapted for LC-MS studies by replacing with 1% acetic acid (ACN-1% acetic acid; 18:82) and the pH was adjusted to 3.0. Extensive degradation was found to occur during alkaline medium stress studies at 2.31 min of retention time at λmax of 235 nm. The mass spectrum of mangiferin, 3 h after treatment with 0.1 M NaOH, clearly shows the rupture of the tricyclic ring, indicating that a fragment at m/z - 269 was formed. Furthermore, the results were supported by nuclear magnetic resonance as well. However, no degradation was observed in other stress conditions.

  19. Degradation of Bimetallic Model Electrocatalysts ___ an in situ XAS Study

    Energy Technology Data Exchange (ETDEWEB)

    Friebel, Daniel

    2011-06-22

    One of the major challenges in the development of clean energy fuel cells is the performance degradation of the electrocatalyst, which, apart from poisoning effects, can suffer from corrosion due to its exposure to a harsh environment under high potentials. In this communication, we demonstrate how interactions of Pt with a transition metal support affect not only, as commonly intended, the catalytic activity, but also the reactivity of Pt towards oxide formation or dissolution. We use two well-defined single-crystal model systems, Pt/Rh(111) and Pt/Au(111) and a unique x-ray spectroscopy technique with enhanced energy resolution to monitor the potential-dependent oxidation state of Pt, and find two markedly different oxidation mechanisms on the two different substrates. This information can be of great significance for future design of more active and more stable catalysts. We have studied the potential-induced degradation of Pt monolayer model electrocatalysts on Rh(111) and Au(111) single-crystal substrates. The anodic formation of Pt oxides was monitored using in situ high energy resolution fluorescence detection x-ray absorption spectroscopy (HERFD XAS). Although Pt was deposited on both substrates in a three-dimensional island growth mode, we observed remarkable differences during oxide formation that can only be understood in terms of strong Pt-substrate interactions throughout the Pt islands. Anodic polarization of Pt/Rh(111) up to +1.6 V vs. RHE (reversible hydrogen electrode) leads to formation an incompletely oxidized passive layer, whereas formation of PtO2 and partial Pt dissolution is observed for Pt/Au(111).

  20. Assessment of land degradation using NASA GIMMS: a case study in Kenya

    NARCIS (Netherlands)

    Dent, D.L.; Bai, Z.G.

    2008-01-01

    Direct assessment of land degradation globally is constrained by limited spatial data~– soil data in particular (see also Chapter 7). As a proxy, biomass has been adopted as an integrated measure of productivity; its deviance from the norm may indicate land degradation or improvement. Biomass can be

  1. Effects of feeding rumen-degradable valine on milk production in late-lactating dairy cows.

    Science.gov (United States)

    Hultquist, Kayla M; Casper, David P

    2016-02-01

    The study objective was to determine if feeding the rumen-degradable AA Val can increase milk production comparable to recombinant bovine somatotropin (bST). Eight multiparous late-lactating (255±26.4 d in milk) Holstein dairy cows were blocked by milk yield (34.1±8.25 kg/d) and randomly assigned to 1 of 4 treatments in a replicated 4×4 Latin square design with 21-d periods (7 d for dietary adaptation and 14 d for data collection). Treatments were control (CON), a single injection of recombinant bST (rbST), and Val fed at 40 (V40) and 80 g/d (V80). Cows were fed a total mixed ration with a distillers dried grains carrier at 113.4 g/d containing none or added AA. Dry matter intake (21.3, 22.0, 22.8, and 21.5 kg/d for CON, rbST, V40, and V80, respectively) was similar among treatments, except cows receiving V40 had greater dry matter intake than cows receiving V80. Milk yield (22.0, 26.1, 25.2, and 24.9 kg/d), 3.5% fat-corrected milk (22.1, 25.4, 24.4, and 24.3 kg/d), and energy-corrected milk (22.7, 26.1, 25.1, and 24.9 kg/d) were increased at similar amounts for cows receiving rbST, V40, and V80 compared with CON cows. Milk fat percentages (3.51, 3.36, 3.32, and 3.38%) were greatest for CON cows compared with cows receiving V40, whereas cows receiving other treatments were intermediate and similar. Milk protein percentages (3.20, 3.12, 3.15, and 3.13%) were greater for CON cows compared with cows receiving rbST and V40, whereas cows receiving V80 were intermediate and similar. Ruminal isobutyrate (1.19, 1.24, 1.44, and 1.74 mol/100 mol) concentrations were increased for cows receiving V40 and V80 compared with CON and rbST cows, with cows receiving V80 having greater concentrations than cows receiving V40. Plasma growth hormone concentrations (1.78, 1.99, 1.55, and 1.45 ng/mL) were greater for cows receiving rbST compared with cows receiving V40 and V80, whereas CON cows were intermediate and similar. Plasma insulin-like growth factor-1 concentrations (60.4, 106

  2. Biogeochemical Cycles in Degraded Lands

    Science.gov (United States)

    Davidson, Eric A.; Vieira, Ima Celia G.; ReisdeCarvalho, Claudio Jose; DeanedeAbreuSa, Tatiana; deSouzaMoutinho, Paulo R.; Figueiredo, Ricardo O.; Stone, Thomas A.

    2004-01-01

    The objectives of this project were to define and describe the types of landscapes that fall under the broad category of "degraded lands" and to study biogeochemical cycles across this range of degradation found in secondary forests. We define degraded land as that which has lost part of its capacity of renovation of a productive ecosystem, either in the context of agroecosystems or as native communities of vegetation. This definition of degradation permits evaluation of biogeochemical constraints to future land uses.

  3. Degradation of fluoroquinolone antibiotics and identification of metabolites/transformation products by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Maia, Alexandra S; Ribeiro, Ana R; Amorim, Catarina L; Barreiro, Juliana C; Cass, Quezia B; Castro, Paula M L; Tiritan, Maria Elizabeth

    2014-03-14

    Antibiotics are a therapeutic class widely found in environmental matrices and extensively studied due to its persistence and implications for multi-resistant bacteria development. This work presents an integrated approach of analytical multi-techniques on assessing biodegradation of fluorinated antibiotics at a laboratory-scale microcosmos to follow removal and formation of intermediate compounds. Degradation of four fluoroquinolone antibiotics, namely Ofloxacin (OFL), Norfloxacin (NOR), Ciprofloxacin (CPF) and Moxifloxacin (MOX), at 10 mg L(-1) using a mixed bacterial culture, was assessed for 60 days. The assays were followed by a developed and validated analytical method of LC with fluorescence detection (LC-FD) using a Luna Pentafluorophenyl (2) 3 μm column. The validated method demonstrated good selectivity, linearity (r(2)>0.999), intra-day and inter-day precisions (RSD<2.74%) and accuracy. The quantification limits were 5 μg L(-1) for OFL, NOR and CPF and 20 μg L(-1) for MOX. The optimized conditions allowed picturing metabolites/transformation products formation and accumulation during the process, stating an incomplete mineralization, also shown by fluoride release. OFL and MOX presented the highest (98.3%) and the lowest (80.5%) extent of degradation after 19 days of assay, respectively. A representative number of samples was selected and analyzed by LC-MS/MS with triple quadrupole and the molecular formulas were confirmed by a quadruple time of flight analyzer (QqTOF). Most of the intermediates were already described as biodegradation and/or photodegradation products in different conditions; however unknown metabolites were also identified. The microbial consortium, even when exposed to high levels of FQ, presented high percentages of degradation, never reported before for these compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Study on Photocatalytic Degradation of Endocrine Disrupting Compound

    Science.gov (United States)

    Pralhad Parihar, Bhagwan; Gupta, Smita; Chakraborty, Mousumi

    2017-07-01

    Propylparaben (PP) is catagorized as endocrine disrupting compounds and is found to be present in urban wastewater comparatively at high concentrations. In the present work, propylparaben was degraded photo-catalytically by optimizing different process parameters such as initial concentration of propylparaben (25mgL-1 to 100 mgL-1), pH of the feed phase and concentration of photocatalyst TiO2 (50 mgL-1 to 200 mgL-1). Finally PP degraded and converted to CO2 and H2O and the degradation was found to follow the first order kinetics.

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

    Institute of Scientific and Technical Information of China (English)

    Meiquan Cai; Liqiu Zhang; Fei Qi; Li Feng

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  7. Degradation kinetics of pharmaceuticals and personal care products in surface waters: photolysis vs biodegradation.

    Science.gov (United States)

    Baena-Nogueras, Rosa María; González-Mazo, Eduardo; Lara-Martín, Pablo A

    2017-07-15

    Poor removal of many pharmaceuticals and personal care products (PPCPs) in sewage treatment leads to their discharge into the receiving waters, where they may cause negative effects. Their elimination from the water column depends of several processes, including photochemical and biological degradation. We have focused this research on comparing the degradation kinetics of a wide number (n=33) of frequently detected PPCPs considering different types of water, pH and solar irradiation. For those compounds that were susceptible of photodegradation, their rates (k) varied from 0.02 to 30.48h(-1) at pH7, with the lowest values for antihypertensive and psychiatric drugs (t1/2>1000h). Modification of the pH turned into faster disappearance of most of the PPCPs (e.g., k=0.072 and 0.066h(-1) for atenolol and carbamazepine at pH4, respectively). On the other hand, biodegradation was enhanced by marine bacteria in many cases, for example for mefenamic acid, caffeine and triclosan (k=0.019, 0.01 and 0.04h(-1), respectively), and was faster for anionic surfactants. Comparing photodegradation and biodegradation processes, hydrochlorothiazide and diclofenac, both not biodegradable, were eliminated exclusively by irradiation (t1/2=0.15-0.43h and t1/2=0.14-0.17h, respectively). Salicylic acid and phenylbutazone were efficiently photo (t1/2<3h) and biodegraded (t1/2=116-158h), whereas some compounds such as ibuprofen, carbamazepine and atenolol had low degradation rates by any of the processes tested (t1/2=23-2310h), making then susceptible to persist in the aquatic media. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Study of distillation and degradation of perfluoro polyether; Estudo da destilacao e degradacao do perfluoropolieter

    Energy Technology Data Exchange (ETDEWEB)

    Lopergolo, Lilian Cristine

    1997-07-01

    Perfluoro-polyethers, PFPE, were first synthesised by Sianesi and collaborators giving rise to a new lubricant oils and greases classes with several applications. Perfluoro polyethers have excellent properties, for instance: high chemical stability and thermal stability, high density, high radiation resistance and excellent lubricating properties. FOMBLIN-Y oil is one of the perfluoro polyethers used as a lubricant in vacuum systems applied in the UF{sub 6} enrichment installations. Due to its excellent properties and for its applications in the nuclear field, IPEN-CNEN/S P had the interest to dominate its production technology with the aim to substitute the commercial FOMBLIN-Y oil used in the national consumption. The FOMBLIN-Y oil synthesis method, adopted in IPEN-CNEN/S P, made by the photooxidation of the hexa fluoro propylene. In this work we study the fraction separation of the national available production with restricted an increased molecular weights which was obtained by fraction distillation in a vacuum according to the ASTM D-1160 norm. We also study the catalytic effect of metals on the thermal stability of perfluoro polyethers. The inertness of perfluoro polyethers at temperatures higher than 300 deg C is strongly affected by presence of some metals. Al and Ti alloys cause fluid degradation at 250 deg C. This degradation is very important because it has a yield increase of the perfluoro polyethers production. (author)

  9. Structural Analysis and Biological Toxicity of Aflatoxins B1 and B2 Degradation Products Following Detoxification by Ocimum basilicum and Cassia fistula Aqueous Extracts.

    Science.gov (United States)

    Iram, Wajiha; Anjum, Tehmina; Iqbal, Mazhar; Ghaffar, Abdul; Abbas, Mateen; Khan, Abdul Muqeet

    2016-01-01

    This study showed the comparison between Ocimum basilicum and Cassia fistula (leaves and branch) aqueous extracts for their ability to detoxify of aflatoxins B1 and B2 (AFB1; 100 μg L(-1) and AFB2; 50 μg L(-1)) by In Vitro assays and decontamination studies. Results indicated that O. basilicum leaves extract was found to be highly significant (P basilicum branch, C. fistula leaves and branch extracts proved to be less efficient in degrading these aflatoxins, under optimized conditions, i.e., pH 8, temperature 30°C and incubation period of 72 h. Moreover the antifungal activity of these plants extracts were also tested. The findings depicted that O. basilicum leaves extract showed maximum growth inhibition of aflatoxigenic isolates, i.e., 82-87% as compared to other tested plants extracts. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that nine degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that O. basilicum leaves extract can be used as an effective tool for the detoxification of aflatoxins.

  10. Fluorescence formation from the interaction of DNA with lipid oxidation degradation products.

    Science.gov (United States)

    Frankel, E N; Neff, W E; Brooks, D D; Fujimoto, K

    1987-06-23

    To clarify the mechanism of fluorescence formation between DNA and lipid degradation products in the presence of ferric chloride and ascorbic acid, a number of carbonyl compounds and decomposition products of pure methyl linolenate hydroperoxides were examined. Keto derivatives of methyl ricinoleate, linoleate, and oleate, alkanals and 2-alkenals produced little or no fluorescence with DNA in the presence of ferric chloride-ascorbic acid. 2,4-Alkadienals were more active and 2,4,7-decatrienal was the most active. Mixtures of volatile aldehydes prepared from linolenate hydroperoxide decomposed either thermally or with iron and ascorbate had the same activity as 2,4,7-decatrienal. Higher molecular-weight products from the decomposition of methyl linolenate hydroperoxides showed relatively low activity. beta-Carotene, alpha-tocopherol and other antioxidants effectively reduced the amount of fluorescence formed by linolenate hydroperoxides. The results suggest that, in addition to hydroperoxide decomposition products, singlet oxygen and/or free radical species contribute significantly to the fluorescence formed from the interaction of methyl linolenate hydroperoxides with DNA in the presence of ferric chloride and ascorbic acid.

  11. Role of Nitrite in Processed Meat Products and its Degradation during their Storage

    Directory of Open Access Journals (Sweden)

    ILIRJANA BOCI

    2014-06-01

    Full Text Available This paper represents the analytical data of nitrite level obtained from the experimental work done on meat processed samples taken from a meat processing plant in Tirana. There has been a long debate and health concern about the nitrite content in meat products. Nitrite is added to e.g. sausages, and hams and other meat products to preserve these products and keep them free from dangerous bacteria. Among the aims are preventing botulism, a dangerous food poison. But also it’s important to use the smallest possible amount of nitrite as a preservative because nitrite in meat can also form nitrosamines, which can damage the health. That’s why the role of nitrite in processed meat and its recommended level conform to new EC Regulations are given in the introduction part of this paper. It is important that the nitrite level be monitored during all the processing steps up to the end consumers. This makes the objective of this paper. It gives the analytical data on nitrite level on meat processed samples taken and tested during their storage and ripening period of time. Different kinds of meat products are taken and tested to evaluate the influence of various parameters (storage time, time until to the end consumers, various kinds of packing in the degradation rate of ingoing nitrite.

  12. Contact sensitizers induce skin inflammation via ROS production and hyaluronic acid degradation.

    Directory of Open Access Journals (Sweden)

    Philipp R Esser

    Full Text Available BACKGROUND: Allergic contact dermatitis (ACD represents a severe health problem with increasing worldwide prevalence. It is a T cell-mediated skin disease induced by protein-reactive organic and inorganic chemicals. A key feature of contact allergens is their ability to trigger an innate immune response that leads to skin inflammation. Previous evidence from the mouse contact hypersensitivity (CHS model suggests a role for endogenous activators of innate immune signaling. Here, we analyzed the role of contact sensitizer induced ROS production and concomitant changes in hyaluronic acid metabolism on CHS responses. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed in vitro and in vivo ROS production using fluorescent ROS detection reagents. HA fragmentation was determined by gel electrophoresis. The influence of blocking ROS production and HA degradation by antioxidants, hyaluronidase-inhibitor or p38 MAPK inhibitor was analyzed in the murine CHS model. Here, we demonstrate that organic contact sensitizers induce production of reactive oxygen species (ROS and a concomitant breakdown of the extracellular matrix (ECM component hyaluronic acid (HA to pro-inflammatory low molecular weight fragments in the skin. Importantly, inhibition of either ROS-mediated or enzymatic HA breakdown prevents sensitization as well as elicitation of CHS. CONCLUSIONS/SIGNIFICANCE: These data identify an indirect mechanism of contact sensitizer induced innate inflammatory signaling involving the breakdown of the ECM and generation of endogenous danger signals. Our findings suggest a beneficial role for anti-oxidants and hyaluronidase inhibitors in prevention and treatment of ACD.

  13. Spatial variation in biodiversity, soil degradation and productivity in agricultural landscapes in the highlands of Tigray, northern Ethiopia

    NARCIS (Netherlands)

    Hadgu, K.M.; Rossing, W.A.H.; Kooistra, L.; Bruggen, van A.H.C.

    2009-01-01

    There is a growing concern about food security and sustainability of agricultural production in developing countries. However, there are limited attempts to quantify agro-biodiversity losses and relate these losses to soil degradation and crop productivity, particularly in Tigray, Ethiopia. In this

  14. Studies on degradation of chlorinated aromatic hydrocarbon by ...

    African Journals Online (AJOL)

    SERVER

    2007-06-04

    Jun 4, 2007 ... that 93 to 95 percentage of chlorobenzene can be decomposed with in 10 min. The immobilized crude ... rmanikandan1968@yahoo.com. sole source of carbon ... Microbial degradation of chloro-substituted aromatics such as ...

  15. Lignin degradation, ligninolytic enzymes activities and exopolysaccharide production by Grifola frondosa strains cultivated on oak sawdust

    Directory of Open Access Journals (Sweden)

    Nona A Mikiashvili

    2011-09-01

    Full Text Available Fourteen strains of Grifola frondosa (Dicks. S. F. Gray, originating from different regions (Asia, Europe and North America were tested for lignin degradation, ligninolytic enzyme activities, protein accumulation and exopolysaccharide production during 55 days of cultivation on oak sawdust. Lignin degradation varied from 2.6 to7.1 % of dry weight of the oak sawdust substrate among tested strains. The loss of dry matter in all screened fungi varied between 11.7 and 33.0%, and the amount of crude protein in the dry substrate varied between 0.94 to 2.55%. The strain, MBFBL 596, had the highest laccase activity (703.3 U/l, and the maximum peroxidase activity of 22.6 U/l was shown by the strain MBFBL 684. Several tested strains (MBFBL 21, 638 and 662 appeared to be good producers of exopolysaccharides (3.5, 3.5 and 3.2 mg/ml respectively.

  16. Studies on alpha-amylase induced degradation of binary polymeric blends of crosslinked starch and pectin.

    Science.gov (United States)

    Bajpai, A K; Shrivastava, Jyoti

    2007-05-01

    A blend matrix of crosslinked starch and pectin was prepared and characterized by infra-red (IR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The prepared blends were investigated kinetically for water sorption studies and alpha-amylase induced degradation adopting a gravimetric procedure. Based on the experimental findings, a plausible mechanism including both diffusion and surface enhanced degradation was suggested and degradation profiles were interpreted. The influence of various factors such as chemical architecture of the blend, pH and temperature of alpha-amylase solution were examined for the swelling and degradation kinetics of crosslinked starch-pectin blends. The effect of concentration of enzyme solution was also studied on the degradation profile of the blends. A correlation was established between the extent of degradation and water imbibing capacity of the degrading blends.

  17. Gas production due to alpha particle degradation of polyethylene and polyvinylchloride

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D.T.; Hoh, J.; Emery, J.; Okajima, S.; Krause, T.

    1998-07-01

    Alpha particle degradation experiments were performed on polyethylene (PE) and polyvinylchloride (PVC) plastic samples typical of Westinghouse Savannah River Company (WSRC) transuranic (TRU) waste. This was done to evaluate the effects of sealing TRU waste during shipment. Experiments were conducted at three temperatures using low dose rates. Predominant products from both plastics were hydrogen, carbon dioxide, and various organic species, with the addition of hydrochloric acid from PVC. In all experiments, the total pressure decreased. Irradiation at 30 and 60 C and at various dose rates caused small changes for both plastics, but at 100 C coupled thermal-radiolytic effects included discoloration of the material as well as large differences in the gas phase composition.

  18. Characterization of degradation products from alkaline wet oxidation of wheat straw

    DEFF Research Database (Denmark)

    Klinke, H.B.; Ahring, B.K.; Schmidt, A.S.

    2002-01-01

    Alkaline wet oxidation pre-treatment (water, sodium carbonate, oxygen, high temperature and pressure) of wheat straw was performed as a 2(4-1) fractional factorial design with the process parameters: temperature, reaction time, sodium carbonate and oxygen. Alkaline wet oxidation was an efficient...... pre-treatment of wheat straw that resulted in solid fractions with high cellulose recovery (96%) and high enzymatic convertibility to glucose (67%). Carbonate and temperature were the most important factors for fractionation of wheat straw by wet oxidation. Optimal conditions were 10 min at 195...... the solid fraction (62%) did not provide a corresponding increase in the phenol monomer content but was correlated to high carboxylic acid concentrations. The degradation products in the hemicellulose fractions co-varied with the pre-treatment conditions in the principal component analysis according...

  19. Detection of aqueous phase chemical warfare agent degradation products by negative mode ion mobility time-of-flight mass spectrometry [IM(tof)MS].

    Science.gov (United States)

    Steiner, Wes E; Harden, Charles S; Hong, Feng; Klopsch, Steve J; Hill, Herbert H; McHugh, Vincent M

    2006-02-01

    The use of negative ion monitoring mode with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer [IM(tof)MS] to detect chemical warfare agent (CWA) degradation products from aqueous phase samples has been determined. Aqueous phase sampling used a traditional electrospray ionization (ESI) source for sample introduction and ionization. Certified reference materials (CRM) of CWA degradation products for the detection of Schedule 1, 2, or 3 toxic chemicals or their precursors as defined by the chemical warfare convention (CWC) treaty verification were used in this study. A mixture of six G-series nerve related CWA degradation products (EMPA, IMPA, EHEP, IHEP, CHMPA, and PMPA) and their related collision induced dissociation (CID) fragment ions (MPA and EPA) were found in each case to be clearly resolved and detected using the IM(tof)MS instrument in negative ion monitoring mode. Corresponding ions, masses, drift times, K(o) values, and signal intensities for each of the CWA degradation products are reported.

  20. Boiling-Water Reactor internals aging degradation study. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Luk, K.H. [Oak Ridge National Lab., TN (United States)

    1993-09-01

    This report documents the results of an aging assessment study for boiling water reactor (BWR) internals. Major stressors for BWR internals are related to unsteady hydrodynamic forces generated by the primary coolant flow in the reactor vessel. Welding and cold-working, dissolved oxygen and impurities in the coolant, applied loads and exposures to fast neutron fluxes are other important stressors. Based on results of a component failure information survey, stress corrosion cracking (SCC) and fatigue are identified as the two major aging-related degradation mechanisms for BWR internals. Significant reported failures include SCC in jet-pump holddown beams, in-core neutron flux monitor dry tubes and core spray spargers. Fatigue failures were detected in feedwater spargers. The implementation of a plant Hydrogen Water Chemistry (HWC) program is considered as a promising method for controlling SCC problems in BWR. More operating data are needed to evaluate its effectiveness for internal components. Long-term fast neutron irradiation effects and high-cycle fatigue in a corrosive environment are uncertainty factors in the aging assessment process. BWR internals are examined by visual inspections and the method is access limited. The presence of a large water gap and an absence of ex-core neutron flux monitors may handicap the use of advanced inspection methods, such as neutron noise vibration measurements, for BWR.

  1. Development and validation of stability-indicating RP-HPLC method for determination of Olmesartan medoxomile in pharmaceutical dosage form and identification, characterization of alkaline degradation impurity of Olmesartan medoxomile drug substance as well as drug product

    Directory of Open Access Journals (Sweden)

    Jain P.S.

    2012-01-01

    Full Text Available Olmesartan Medoxomil (OLME belongs to a group of angiotensin II receptor blockers used as an antihypertensive agent and is currently being used for prevention of Hypertension. This paper describes the Validation and development of stability indicating RP-HPLC method for the determination of OLME in the presence of its degradation products generated from forced degradation study and characterization of degradation product (impurity. The assay involved gradient elution of OLME on An LC GC BDS C18 column (250 × 4.5mm, 5-μm particle size was employed for loading the sample. The mobile phase A consists of 7 ml Triethylamine in 1000 ml water (pH adjusted to 3.0 with orthophosphoric acid and B contains acetonitrile. Quantification was achieved with photodiode array detection at 257 nm. The chromatographic separation was obtained with a retention time of 6.72 min, and the method was linear in the range 50-150 µg/ml. The method was validated according to the ICH guidelines with respect to linearity, precision, accuracy, limit of detection (LOD, limit of quantification (LOQ, specificity and robustness. Impurity found in stressed and stability studies of Olmesartan Medoxomil in both drug substance and drug product are described. This degradation product is identified as 1-(biphenyl-4-ylmethyl-1H-imidazole-5-carboxylic acid. An Alkaline degradation pathway of Olmesartan medoxomil, for the formation of this degradation product, has been proposed and degradation product was characterized.

  2. Characterisation of the non-asphaltene products of mild chemical degradation of asphaltenes

    Energy Technology Data Exchange (ETDEWEB)

    Ekweozor, C.M.

    1986-01-01

    The major steranes of the non-asphaltene fraction of Nigerian tar sand bitumen (maltene) are the C{sub 27-29} and C{sub 28-29} regular steranes. The reducing-metal reaction products of the corresponding asphaltenes (maltene-I) contain mainly C{sub 27-29} regular steranes with the 14{beta}(H),17{beta}(H);20R+S and 14{alpha}(H),17{alpha}(H);20R+S configurations as well as the corresponding diasteranes having the 13{beta}(H),17{alpha}(H);20R+S configuration. These sterane distributions suggest that maltene-I corresponds to an unaltered oil while the maltene is equivalent to the product of severe biodegradation of maltene-I. This is consistent with maltene-I being the remnant of original oil trapped within the asphaltene matrix and protected from the effect of in-reservoir biodegradation. Degradation of Nigerian asphaltenes by refluxing with ferric chloride-acetic anhydride or methanolic potassium hydroxide also releases soluble reaction products having the characteristics of unaltered oil such as the presence of n-alkanes having an unbiased distribution. These methods appear to be milder and more suitable than reducing-metal reactions for releasing hydrocarbons occluded by asphaltenes. 15 refs., 3 figs., 2 tabs.

  3. Characterization of the non-asphaltene products of mild chemical degradation of asphaltenes

    Energy Technology Data Exchange (ETDEWEB)

    Ekweozor, C.M.

    1986-01-01

    The major steranes of the non-asphaltene fraction of Nigerian tar sand bitumen (maltene) are the C/sub 27/-C/sub 29/ diasteranes (13..beta.. (H),17..cap alpha.. (H); 20 R + S) and C/sub 28/-C/sub 29/ regular steranes (14..beta.. (H),17..beta.. (H); 20S). The reducing metal reaction products of the corresponding asphaltenes (maltene-I) contain mainly C/sub 27/-C/sub 29/ regular steranes with the 14..beta.. (H),17..beta.. (H); 20R + S and 14..cap alpha.. (H),17..cap alpha.. (H); 20R + S configurations as well as the corresponding diasteranes having the 13..beta.. (H),17..cap alpha.. (H); 20R + S configuration. These sterane distributions suggest that maltene-I corresponds to an unaltered oil whilst the maltene is equivalent to the product of severe biodegradation of maltene-I. This is consistent with maltene-I being the remnant of original oil trapped within the asphaltene matrix and protected from the effect of in-reservoir biodegradation. Degradation of Nigerian asphaltenes by refluxing with ferric chloride-acetic anhydride or methanolic potassium hydroxide also releases soluble reaction products having the characteristics of unaltered oil such as the presence of n-alkanes having an unbiased distribution. These methods appear to be milder and more suitable than reducing metal reactions for releasing hydrocarbons occluded by asphaltenes.

  4. Heterologous Expression of Plant Cell Wall Degrading Enzymes for Effective Production of Cellulosic Biofuels

    Science.gov (United States)

    Jung, Sang-Kyu; Parisutham, Vinuselvi; Jeong, Seong Hun; Lee, Sung Kuk

    2012-01-01

    A major technical challenge in the cost-effective production of cellulosic biofuel is the need to lower the cost of plant cell wall degrading enzymes (PCDE), which is required for the production of sugars from biomass. Several competitive, low-cost technologies have been developed to produce PCDE in different host organisms such as Escherichia coli, Zymomonas mobilis, and plant. Selection of an ideal host organism is very important, because each host organism has its own unique features. Synthetic biology-aided tools enable heterologous expression of PCDE in recombinant E. coli or Z. mobilis and allow successful consolidated bioprocessing (CBP) in these microorganisms. In-planta expression provides an opportunity to simplify the process of enzyme production and plant biomass processing and leads to self-deconstruction of plant cell walls. Although the future of currently available technologies is difficult to predict, a complete and viable platform will most likely be available through the integration of the existing approaches with the development of breakthrough technologies. PMID:22911272

  5. Impact of enzymatic pretreatment on corn stover degradation and biogas production.

    Science.gov (United States)

    Schroyen, Michel; Vervaeren, Han; Van Hulle, Stijn W H; Raes, Katleen

    2014-12-01

    Corn stover is an agricultural residue consisting of lignocellulose, cellulose and hemicellulose polymers, sheeted in a lignin barrier. Corn stover can be used as feedstock for biogas production. Previous studies have shown biological pretreatment of lignocellulose materials can increase digestibility of the substrate improving hydrolysis, the rate-limiting step in biogas production. The impact of pretreating with different enzymes (laccase, manganese peroxidase and versatile peroxidase) and different incubation times, (0, 6 and 24 h) was studied. The effect on the matrix and biomethane production was determined. Pretreatments did not yield high concentrations of phenolic compounds, inhibitors of biogas production. The laccase enzyme showed an increase in biomethane production of 25% after 24 h of incubation. Pretreatment with peroxidase enzymes increased biomethane production with 17% after 6 h of incubation. As such it can be concluded that by introducing the different enzymes at different stages during pretreatment an increased biomethane production can be obtained.

  6. Development of tools for genetic analysis of phenanthrene degradation and nanopod production by Delftia sp. Cs1-4

    Directory of Open Access Journals (Sweden)

    William James Hickey

    2011-10-01

    Full Text Available The bacterium Delftia sp. Cs1-4 produces novel extracellular structures (nanopods in conjunction with its growth on phenanthrene. While a full genome sequence is available for Strain Cs1-4, genetic tools that could be applied to study phenanthrene degradation/nanopod production have not been reported. Thus, the objectives of this study were to establish such tools, and apply them for molecular analysis of nanopod formation and/or phenanthrene degradation. Three types of tools were developed and/or validated. First, we developed a new expression system based on a strong promoter controlling expression of a surface layer protein (NpdA from Delftia sp. Cs1-4, which was ca. 2,500-fold stronger than the widely used lactose promoter. Second, the Cre-loxP system was validated for generation of markerless, in-frame, gene deletions, and for in-frame gene insertions. The gene deletion function was applied to examine potential roles in nanopod formation of three genes (omp32, lasI, and hcp, while the gene insertion function was used for reporter gene tagging of npdA. Lastly, pMiniHimar was modified to enhance gene recovery and mutant analysis in genome-wide transposon mutagenesis. Application of the latter to strain Cs1-4, several new genes with potential roles in phenanthrene degradation or npdA expression were identified. Collectively, the availability of these tools has opened new avenues of investigation in Delftia sp. Cs1-4 and other related genera/species with importance in environmental toxicology.

  7. Engineered yeast whole-cell biocatalyst for direct degradation of alginate from macroalgae and production of non-commercialized useful monosaccharide from alginate.

    Science.gov (United States)

    Takagi, Toshiyuki; Yokoi, Takahiro; Shibata, Toshiyuki; Morisaka, Hironobu; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2016-02-01

    Alginate is a major component of brown macroalgae. In macroalgae, an endolytic alginate lyase first degrades alginate into oligosaccharides. These oligosaccharides are further broken down into monosaccharides by an exolytic alginate lyase. In this study, genes encoding various alginate lyases derived from alginate-assimilating marine bacterium Saccharophagus degradans were isolated, and their enzymes were displayed using the yeast cell surface display system. Alg7A-, Alg7D-, and Alg18J-displaying yeasts showed endolytic alginate lyase activity. On the other hand, Alg7K-displaying yeast showed exolytic alginate lyase activity. Alg7A, Alg7D, Alg7K, and Alg18J, when displayed on yeast cell surface, demonstrated both polyguluronate lyase and polymannuronate lyase activities. Additionally, polyguluronic acid could be much easily degraded by Alg7A, Alg7K, and Alg7D than polymannuronic acid. In contrast, polymannuronic acid could be much easily degraded by Alg18J than polyguluronic acid. We further constructed yeasts co-displaying endolytic and exolytic alginate lyases. Degradation efficiency by the co-displaying yeasts were significantly higher than single alginate lyase-displaying yeasts. Alg7A/Alg7K co-displaying yeast had maximum alginate degrading activity, with production of 1.98 g/L of reducing sugars in a 60-min reaction. This system developed, along with our findings, will contribute to the efficient utilization and production of useful and non-commercialized monosaccharides from alginate by Saccharomyces cerevisiae.

  8. Degradation of cellulosic biomass and its subsequent utilization for the production of chemical feedstocks. Progress report, June 1-August 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.I.C.; Cooney, C.L.; Demain, A.L.; Gomez, R.F.; Sinskey, A.J.

    1978-08-01

    Studies concerning the cellobiose properties of Clostridium thermocellum were started to determine if the cellulose degradation end products can be enhanced for glucose (with a subsequent decrease in cellobiose). Implications of preliminary studies indicate that the cells or the enzyme(s) responsible for converting cellobiose to glucose can be manipulated environmentally and genetically to increase the final yield of glucose. The second area of effort is to the production of chemical feedstocks. Three fermentations have been identified for exploration. Preliminary reports on acrylic acid acetone/butanol, and acetic acid production by C. propionicum, C. acetobutylicum, and C. thermoaceticum, respectively, are included. (DMC)

  9. Phenol Is the Initial Product Formed during Growth and Degradation of Bromobenzene by Tropical Marine Yeast, Yarrowia lipolytica NCIM 3589 via an Early Dehalogenation Step

    Directory of Open Access Journals (Sweden)

    Aakanksha A. Vatsal

    2017-06-01

    Full Text Available Bromobenzene (BrB, a hydrophobic, recalcitrant organic compound, is listed by the environmental protection agencies as an environmental and marine pollutant having hepatotoxic, mutagenic, teratogenic, and carcinogenic effects. The tropical marine yeast Yarrowia lipolytica 3589 was seen to grow aerobically on BrB and displayed a maximum growth rate (μmax of 0.04 h-1. Furthermore, we also observed an increase in cell size and sedimentation velocity for the cells grown on BrB as compared to the glucose grown cells. The cells attached to the hydrophobic bromobenzene droplets through its hydrophobic and acid–base interactions. The BrB (0.5%, 47.6 mM was utilized by the cells with the release of a corresponding amount of bromide (12.87 mM and yielded a cell mass of 1.86 g/L after showing 34% degradation in 96 h. Maximum dehalogenase activity of 16.16 U/mL was seen in the cell free supernatant after 24 h of growth. Identification of metabolites formed as a result of BrB degradation, namely, phenol, catechol, cis, cis muconic acid, and carbon dioxide were determined by LC–MS and GC–MS. The initial attack on bromobenzene by Y. lipolytica cells lead to the transient accumulation of phenol as an early intermediate which is being reported for the first time. Degradation of phenol led to catechol which was degraded by the ortho- cleavage pathway forming cis, cis muconic acid and then to Krebs cycle intermediates eventually leading to CO2 production. The study shows that dehalogenation via an extracellular dehalogenase occurs prior to ring cleavage with phenol as the preliminary degradative compound being produced. The yeast was also able to grow on the degradative products, i.e., phenol and catechol, to varying degrees which would be of potential relevance in the degradation and remediation of xenobiotic environmental bromoaromatic pollutants such as bromobenzene.

  10. Photochemical degradation of atrazine in UV and UV/H2O2 process: pathways and toxic effects of products.

    Science.gov (United States)

    Choi, Hyun-Jin; Kim, Daekeun; Lee, Tae-Jin

    2013-01-01

    The degradation of atrazine in aqueous solution by UV or UV/H2O2 processes, and the toxic effects of the degradation products were explored. The mineralization of atrazine was not observed in the UV irradiation process, resulting in the production of hydroxyatrazine (OIET) as the final product. In the UV/H2O2 process, the final product was ammeline (OAAT), which was obtained by two different pathways of reaction: dechlorination followed by hydroxylation, and the de-alkylation of atrazine. The by-products of the reaction of dechlorination followed by hydroxylation were OIET and hydroxydeethyl atrazine (OIAT), and those of de-alkylation were deisopropyl atrazine (CEAT), deethyl atrazine (CIAT), and deethyldeisopropyl atrazine (CAAT). OIAT and OAAT appeared to be quite stable in the degradation of atrazine by the UV/H2O2 process. In a toxicity test using Daphnia magna, the acute toxic unit (TUa) was less than 1 of TUa (100/EC50, %) in the UV/H2O2 process after 30 min of reaction time, while 1.2 to 1.3 of TUa was observed in the UV process. The TUa values of atrazine and the degradation products have the following decreasing order: OIET> Atrazine> CEAT≈CIAT> CAAT. OIAT and OAAT did not show any toxic effects.

  11. HS-SPME-GC-MS analysis of antioxidant degradation products migrating to drinking water from PE materials and PEX pipes

    DEFF Research Database (Denmark)

    Lützhøft, Hans-Christian Holten; Waul, Christopher Kevin; Andersen, Henrik Rasmus

    2013-01-01

    Polyethylene (PE) and cross-linked polyethylene (PEX) pipes are frequently used in water supply systems. Such pipes contain added antioxidants with phenolic structures, e.g. Irgafos 168, Irganox 1010 and 1076, in order to improve durability. However, phenol, ketone and quinone antioxidant...... degradation products may leach and enter drinking water. The aim of this investigation was to develop a method for measuring these degradation products with a performance meeting the drinking water quality criteria of 20 µg L−1. Using headspace solid phase microextraction coupled to a gas chromatograph...

  12. Availability of the B beta(15-21) epitope on cross-linked human fibrin and its plasmic degradation products

    Science.gov (United States)

    Chen, F.; Haber, E.; Matsueda, G. R.

    1992-01-01

    The binding of radiolabeled monoclonal antifibrin antibody 59D8 (specific for fibrin but not fibrinogen) to a series of degraded fibrin clots showed that the availability of the B beta(15-21) epitope (against which 59D8 had been raised) was inversely proportional to the extent of clot lysis. Examination of digest supernatants revealed that the B beta(15-21) epitope was released from clots as a high molecular weight degradation product in the presence of calcium ions but that the generation of low molecular weight peptides occurred in the absence of calcium ions. To address the question of epitope accessibility, we compared levels of fibrin clot binding among four radioactively labeled antibodies: antifibrin monoclonal antibody 59D8, two antifibrinogen monoclonal antibodies that cross-reacted with fibrin, and an affinity-purified polyclonal antifibrinogen antibody. We expected that the antifibrinogen antibodies would show enhanced binding to clots in comparison with the antifibrin antibody. However, the epitope accessibility experiments showed that all four antibody preparations bound fibrin clots at comparable levels. Taken together, these studies demonstrated that one fibrin-specific epitope, B beta(15-21), remains available on clots as they undergo degradation by plasmin and, importantly, that the epitope is not solubilized at a rate faster than the rate at which the clot is itself solubilized. The availability of the B beta(15-21) epitope during the course of plasminolysis assures the potential utility of antifibrin antibodies such as 59D8 for detecting thrombi and targeting plasminogen activators.

  13. Possible atmospheric lifetimes and chemical reaction mechanisms for selected HCFCs, HFCs, CH3CCl3, and their degradation products against dissolution and/or degradation in seawater and cloudwater

    Science.gov (United States)

    Wine, P. H.; Chameides, W. L.

    1990-01-01

    For a wide variety of atmospheric species including CO2, HNO3, and SO2, dissolution in seawater or cloudwater followed by hydrolysis or chemical reaction represents a primary pathway for removal from the atmosphere. In order to determine if this mechanism can also remove significant amounts of atmospheric chlorofluorocarbons (HCFC's), fluorocarbons (HFC's), and their degradation products, an investigation was undertaken as part of the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS). In this investigation, the rates at which CHCl2CF3 (HCFC-123), CCl2FCH3 (HCFC-141b), CClF2CH3 (HCFC-142b), CHClF2 (HCFC-22), CHClFCF3 (HCFC-124) CH2FCF3 (HFC-134a) CHF2CH3 (HFC-152a), CHF2CF3 (HFC-125), and CH3CCl3 can be dissolved in the oceans and in cloudwater were estimated from the species' thermodynamic and chemical properties using simple mathematical formulations to simulate the transfer of gases from the atmosphere to the ocean or cloudwater. The ability of cloudwater and rainwater to remove gas phase degradation products of these compounds was also considered as was the aqueous phase chemistry of the degradation products. The results of this investigation are described.

  14. Effort of Increasing Production of Livestock Feed out of Cassava Waste by Identifying the more Suitable Cellulotic Degrading Fungi

    Directory of Open Access Journals (Sweden)

    Yani Suryani

    2012-09-01

    Full Text Available In the bioethanol production process, as much as 90% of waste was produced. The availability of waste production is very important since waste can be processed to become livestock feed. The solid bioethanol waste contains cyanide (HCN 5.8177 mg/kg, water 95,21%, ash 0,39%, protein 8,16%, crude fiber 5,45%, crude fat 2.06%, and carbohydrates 83,94%. Processing bioethanol solid waste into livestock feed can be done by utilizing the existing fungi on bioethanol solid waste. Crude fiber (cellulose and carbohydrates are a source of cellulolytic fungi. Cellulolytic fungi can degrade the role of organic materials contained in bioethanol solid waste, so that it can be made as a source of highly nutritious livestock feed. This study aims to determine the types of cellulolytic fungal isolates contained in bioethanol solid waste which is potentially processed to become livestock woof. Descriptive analysis was employed as a method of the study. Furthermore, Potato Dextrose Agar (PDA was used as a medium for culturing and isolating the fungus. Dilution series and pour plate method were employed to isolate the fungus. And, Moist Chamber method was employed to identify it. In addition, Carboxy Methyl Cellulose (CMC was used as medium to identify cellulolytic fungi. The process was carried out up to the level of genus based on macroscopic and microscopic characterization. 10 fungal isolates from the genus of Aspergillus sp 1, Aspergillus sp 2, Aspergillus sp 3, Aspergillus niger, Cladosporium sp, Mucor sp, Penicillium sp 1, Penicillium sp 2, Rhizopus sp and Trichoderma viride were yielded in this study. The results of examining cellulose enzyme activity revealed that 9 of 10 isolates of the fungus were capable of degrading cellulose. Isolates yielding the largest cellulose enzyme were Trichoderma viride, Penicillium sp 1, Cladosporium sp and Aspergillus niger.

  15. Photocatalytic degradation of methamphetamine by UV/TiO2 - kinetics, intermediates, and products.

    Science.gov (United States)

    Kuo, Chin-Sheng; Lin, Cheng-Fang; Hong, Pui-Kwan Andy

    2015-05-01

    Methamphetamine (MAT) is a prescription drug and often a substance of abuse. It is found in WWTP influents and effluents as well as surface waters in many regions, elevating concerns about their potential impact. MAT is not effectively removed by conventional processes of domestic wastewater treatment plants (WWTPs). To contemplate advanced treatment, this study evaluates the feasibility of eliminating MAT by UV-illuminated TiO2, a potential retrofit to existing UV disinfection units. The degradation kinetics and mechanism of MAT by TiO2 under low-wattage UV illumination (9 W with maximum output at 365 nm) were investigated. Experimental parameters were varied including the TiO2 loading, MAT concentration, and pH. During treatment, MAT and its intermediates were tracked by HPLC-MS/MS, along with TOC and IC measurements to determine the mineralization extent. In contact with 0.1 g/L of TiO2 under illumination at pH 7, an entire spike amount of 100 μg/L of MAT was removed from deionized water after 3 min and 76 μg/L of MAT was removed from the secondary wastewater effluent after 30 min. The degradation of MAT followed an apparent first-order kinetics. Near complete mineralization of MAT from 10 mg/L was achieved in 180 min with 0.1 g/L of TiO2 at pH 5, by which the organic nitrogen was converted to NH4(+) and NO3(-). Based on identified intermediates, two degradation pathways were deduced that involved cleavage of the side chain as well as hydroxylation of the MAT compound. The photocatalytic UV/TiO2 process shows promise in arresting the release of MAT and its intermediate derivatives into the water environment.

  16. Thermal degradation events as health hazards: Particle vs gas phase effects, mechanistic studies with particles

    Science.gov (United States)

    Oberdörster, G.; Ferin, J.; Finkelstein, J.; Soderholm, S.

    Exposure to thermal degradation products arising from fire or smoke could be a major concern for manned space missions. Severe acute lung damage has been reported in people after accidental exposure to fumes from plastic materials, and animal studies revealed the extremely high toxicity of freshly generated fumes whereas a decrease in toxicity of aged fumes has been found. This and the fact that toxicity of the freshly generated fumes can be prevented with filters raises the question whether the toxicity may be due to the particulate rather than the gas phase components of the thermodegradation products. Indeed, results from recent studies implicate ultrafine particles (particle diameter in the nm range) as potential severe pulmonary toxicants. We have conducted a number of in vivo (inhalation and instillation studies in rats) and in vitro studies to test the hypothesis that ultrafine particles possess an increased potential to injure the lung compared to larger-sized particles. We used as surrogate particles ultrafine TiO 2 particles (12 and 20 nm diameter). Results in exposed rats showed that the ultrafine TiO 2 particles not only induce a greater acute inflammatory reaction in the lung than larger-sized TiO 2 particles, but can also lead to persistent chronic effects, as indicated by an adverse effect on alveolar macrophage mediated clearance function of particles. Release of mediators from alveolar macrophages during phagocytosis of the ultrafine particles and an increased access of the ultrafine particles to the pulmonary interstitium are likely factors contributing to their pulmonary toxicity. In vitro studies with lung cells (alveolar macrophages) showed, in addition, that ultrafine TiO 2 particles have a greater potential to induce cytokines than larger-sized particles. We conclude from our present studies that ultrafine particles have a significant potential to injure the lung and that their occurrence in thermal degradation events can play a major role in

  17. Production of activated carbon by waste tire thermochemical degradation with CO2.

    Science.gov (United States)

    Betancur, Mariluz; Martínez, Juan Daniel; Murillo, Ramón

    2009-09-15

    The thermochemical degradation of waste tires in a CO(2) atmosphere without previous treatment of devolatilization (pyrolysis) in order to obtain activated carbons with good textural properties such as surface area and porosity was studied. The operating variables studied were CO(2) flow rate (50 and 150 mL/min), temperature (800 and 900 degrees C) and reaction time (1, 1.5, 2, 2.5 and 3h). Results show a considerable effect of the temperature and the reaction time in the porosity development. Kinetic measurements showed that the reactions involved in the thermochemical degradation of waste tire with CO(2), are similar to those developed in the pyrolysis process carried out under N(2) atmosphere and temperatures below 760 degrees C, for particles sizes of 500 microm and heating rate of 5 degrees C/min. For temperatures higher than 760 degrees C the CO(2) starts to oxidize the remaining carbon black. Activated carbon with a 414-m(2)/g surface area at 900 degrees C of temperature, 150 mL/min of CO(2) volumetric flow and 180 min of reaction time was obtained. In this work it is considering the no reactivity of CO(2) for devolatilization of the tires (up to 760 degrees C), and also the partial oxidation of residual char at high temperature for activation (>760 degrees C). It is confirmed that there are two consecutive stages (devolatilization and activation) developed from the same process.

  18. Degradation of bisphenol A by ozonation: rate constants, influence of inorganic anions, and by-products

    Directory of Open Access Journals (Sweden)

    Kheng Soo Tay

    2012-02-01

    Full Text Available The second-order rate constants for the reaction between bisphenol A (BPA and ozonewere evaluated over the pH range of 2-12. The rate constants showed minimum values (×104 M-1s-1under acidic condition (pH 10. From pH 4 to 7, the second-order rate constants were found to increase by a magnitudeof almost 102 and this was due to the increase in anionic BPA species in the solution. The rateconstants increased almost twofold when pH increased from 9.6 to 10.2. The presence of commoninorganic anions at levels commonly found in the environment did not affect the rate of degradationof BPA.The degradation by-products from the ozonation of BPA were identified as 4-(prop-1-en-2-ylphenol, hydroquinone, 4-hydroxyacetophenone, 2-(2-(4-hydroxyphenylpropan-2-ylsuccinaldehyde,2-(1-(4-hydroxyphenylvinylpent-2-enal, 3-formyl-4-(4-hydroxyphenyl-4-methylpent-2-enoic acid, monohydroxy-BPA and dihydroxy-BPA. In conclusion, ozonation was found to be aneffective method for the removal of BPA even in the presence of common inorganic anions atenvironmental concentrations. However, incomplete treatment of BPA might produce a variety ofdegradation by-products.

  19. Development of enzyme immunoassay for captan and its degradation product tetrahydrophthalimide in foods.

    Science.gov (United States)

    Newsome, W H; Yeung, J M; Collins, P G

    1993-01-01

    A simple, sensitive, and precise enzyme-linked immunosorbent assay (ELISA) is described for the quantitation of captan as its degradation product tetrahydrophthalimide (THPI) in foods using polyclonal antibodies. Three hapten analogues of THPI with different alkyl spacer arm lengths were synthesized. Immunogens and coating proteins were prepared by coupling these haptens to human serum albumin and ovalbumin, respectively. A 5-carbon spacer arm appeared to be optimum for the production of antibodies. Heterologous coating proteins did not improve the sensitivity, but reduction of homologous coating protein concentration did improve the sensitivity, resulting in a concentration of test compound required to inhibit binding by 50% of 15.5 ng/mL. The antiserum is specific for captan, captafol, and THPI, but not other structurally related compounds. The minimum detection limit was 1 ng/mL; the linearity was 1-200 ng/mL. The overall recoveries of captan and THPI from 11 commodities spiked at 4 levels were 92 and 100%, respectively. The intra-assay and interassay coefficients of variation were 9.1 and 16.8% for apple blanks and 5.9 and 4.2% for apple spiked with 3 ppm THPI, respectively. The ELISA described is suitable for measuring captan and THPI at levels comparable to those typically found in fruit.

  20. Cellulase production from treated oil palm empty fruit bunch degradation by locally isolated Thermobifida fusca

    Directory of Open Access Journals (Sweden)

    M. Nazli Naim

    2013-02-01

    Full Text Available The aim of this research was to evaluate the production of cellulases from locally isolated bacteria, Thermobifida fusca, using thermal and chemical treated oil palm empty fruit bunch (OPEFB as substrate in liquid-state fermentation (LSF. T. fusca was successfully isolated and was a dominant cellulase producer in OPEFB composting at the thermophilic stage. Analysis of the surface morphology of OPEFB samples using Scanning Electron Microscopy (SEM showed that the most significant changes after the combination of thermal and chemical pretreatment was the removal of silica bodies, and this observation was supported by X-ray Diffraction analysis (XRD, Fourier Transform Infrared (FTIR, and Thermogravimetric analysis (TG showing changes on the hemicelluloses, cellulose, and lignin structures throughout the pretreatment process. As a result of the pretreatment, higher cellulase production by T. fusca was obtained. The highest activity for CMCase, FPase, and β-glucosidase using optimally treated OPEFB were 0.24 U/mL, 0.34 U/mL, and 0.04 U/mL, respectively. Therefore, it can be suggested that the combination of chemical and thermal pretreatments enhances the degradation of OPEFB for subsequent use as fermentation substrate, contributing to a higher cellulases yield by T. fusca.

  1. RP-HPLC Method for the Determination of Cinitapride in the Presence of its Degradation Products in Bulk Drug

    Directory of Open Access Journals (Sweden)

    S. M. N. Roy

    2010-01-01

    Full Text Available A reverse phase HPLC method is described for the determination of cinitapride hydrogen tartrate in the presence of its degradation products in bulk drug. A drug was subjected to all stress conditions such as reduction, oxidation acidic and alkaline medium. Chromatography was recorded on an Intersil ODS-3 column using mixture of acetonitrile and phosphate buffer, pH adjusted to 6.7 in the ratio (70:30 v/v as the mobile phase at the rate of 1.0 mL/min with detection at 260 nm. Glimepride was used as internal standard. The retention time of drug cinitapride was 3.8 min and glimepride an internal standard was 2.5 minute. The drug was found to degrade extensively in reduction conditions and mild degradation in the presence of in alkaline, acidic and oxidative but the drug was stable in thermal stress. The method was validated by determining its specificity, linearity, precision and accuracy. The developed method with good separation of all degradation products from drug could be successfully applied for the determination of cinitapride in the presence of its degradation products in the bulk drug. The proposed method is simple, fast, accurate and precise and hence applied for routine quality control of cinitapride in bulk drug. It can be used for analysis of samples during stability testing.

  2. Study of 4-t-octylphenol degradation and microbial community in granular sludge

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this study, the authors have investigated the effects of various factors on both aerobic and anaerobic degradation of 4-t-octylphenol (4-t-OP) in granular sludge. In comparison, the aerobic degradation rate was much higher than that of anaerobic degradation. The optimal pH values for 4-t-OP degradation in granular sludge were 9 and 7 under aerobic and anaerobic conditions, respectively. And the degradation rate decreased with an increase in the initial 4-t-OP concentration. Addition of yeast extract or homologous compounds such as phenol also enhanced the 4-t-OP degradation, especially under the aerobic condition. To investigate the bacterial community in this study, the denaturing gradient gel electrophoresis (DGGE) method was applied, based on the primers, for the 16S rDNA V3 region of bacteria. γ-proteobacteria and bacillus were identified as the major species of sludge.

  3. Study of Degradation Kinetics of Parathion Methyl On Mixed Nanocrystalline Titania-Zirconium and Titania-Cerium Oxides

    Science.gov (United States)

    Kuráň, Pavel; Pšenička, Martin; Šťastný, Martin; Benkocká, Monika; Janoš, Pavel

    2016-10-01

    The unique surface properties of some nanocrystalline metal oxides and their application for removal of various toxic compounds were reported in early 1990s. Recently, a reliable method for the preparation of reactive cerium dioxide sorbent and its application for degradation of the organophosphate pesticides, such as parathion methyl, chlorpyrifos, dichlofenthion, fenchlorphos, and prothiofos, as well as of some chemical warfare agents-nerve gases soman and O-ethyl S-[2-(diisopropylamino) ethyl] methylphosphonothioate (VX) was published. This paper reports on the kinetics study of degradation of parathion methyl as a representative organophosphate on nanocrystalline metal oxides TiO2, ZrO2, CeO2 and their mixtures in different molar ratios of particular elements. The tested sorbents except of CeO2 were prepared by different methods (e.g. sol-gel, precipitation) in cooperation with Institute of Inorganic Chemistry (Rez, Czech Republic). The degradation kinetics of parathion methyl on tested sorbents was followed by HPLC equipped with diode array detector. The basic kinetics parameters (half-lives of parathion methyl degradation, rate constants of degradation product formation) were calculated for each sorbent from Weber-Morris equation of 1st order diffusion kinetic model. The results proved the ability of prepared sorbents to degrade parathion methyl under formation of 4-nitrophenol as the main degradation product. The most efficient sorbents were TiCe (2:8), TiCe (1:1), TiCe (0:1) (50-70 %) followed by TiZr (1:1), TiCe (8:2), TiZr (8:2), TiZr (2:8) (20-30%) and TiO2, ZrO2 (less than 5 %).

  4. Solar photolysis versus TiO2-mediated solar photocatalysis: a kinetic study of the degradation of naproxen and diclofenac in various water matrices.

    Science.gov (United States)

    Kanakaraju, Devagi; Motti, Cherie A; Glass, Beverley D; Oelgemöller, Michael

    2016-09-01

    Given that drugs and their degradation products are likely to occur as concoctions in wastewater, the degradation of a mixture of two nonsteroidal anti-inflammatory drugs (NSAIDs), diclofenac (DCF) and naproxen (NPX), was investigated by solar photolysis and titanium dioxide (TiO2)-mediated solar photocatalysis using an immersion-well photoreactor. An equimolar ratio (1:1) of both NSAIDs in distilled water, drinking water, and river water was subjected to solar degradation. Solar photolysis of the DCF and NPX mixture was competitive particularly in drinking water and river water, as both drugs have the ability to undergo photolysis. However, the addition of TiO2 in the mixture significantly enhanced the degradation rate of both APIs compared to solar photolysis alone. Mineralization, as measured by chemical oxygen demand (COD), was incomplete under all conditions investigated. TiO2-mediated solar photocatalytic degradation of DCF and NPX mixtures produced 15 identifiable degradants corresponding to degradation of the individual NSAIDs, while two degradation products with much higher molecular weight than the parent NSAIDs were identified by liquid chromatography mass spectrometry (LC-MS) and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). This study showed that the solar light intensity and the water matrix appear to be the main factors influencing the overall performance of the solar photolysis and TiO2-mediated solar photocatalysis for degradation of DCF and NPX mixtures.

  5. Marketing study: sealskin products

    National Research Council Canada - National Science Library

    1985-01-01

    This is a draft report prepared for the Canadian Sealers Association incorporating findings of a three phase study conducted to determine the potential for the Newfoundland and Labrador sealskin craft industry...

  6. Structure elucidation and in vitro cytotoxicity of ochratoxin α amide, a new degradation product of ochratoxin A.

    Science.gov (United States)

    Bittner, Andrea; Cramer, Benedikt; Harrer, Henning; Humpf, Hans-Ulrich

    2015-05-01

    The mycotoxin ochratoxin A is a secondary metabolite occurring in a wide range of commodities. During the exposure of ochratoxin A to white and blue light, a cleavage between the carbon atom C-14 and the nitrogen atom was described. As a reaction product, the new compound ochratoxin α amide has been proposed based on mass spectrometry (MS) experiments. In the following study, we observed that this compound is also formed at high temperatures such as used for example during coffee roasting and therefore represents a further thermal ochratoxin A degradation product. To confirm the structure of ochratoxin α amide, the compound was prepared in large scale and complete structure elucidation via nuclear magnetic resonance (NMR) and MS was performed. Additionally, first studies on the toxicity of ochratoxin α amide were performed using immortalized human kidney epithelial (IHKE) cells, a cell line known to be sensitive against ochratoxin A with an IC50 value of 0.5 μM. Using this system, ochratoxin α amide revealed no cytotoxicity up to concentrations of 50 μM. Thus, these results propose that the thermal degradation of ochratoxin A to ochratoxin α amide might be a detoxification process. Finally, we present a sample preparation and a HPLC-tandem mass spectrometry (HPLC-MS/MS) method for the analysis of ochratoxin α amide in extrudates and checked its formation during the extrusion of artificially contaminated wheat grits at 150 and 180 °C, whereas no ochratoxin α amide was detectable under these conditions.

  7. Pseudomonas pseudoalcaligenes CECT5344, a cyanide-degrading bacterium with by-product (polyhydroxyalkanoates) formation capacity.

    Science.gov (United States)

    Manso Cobos, Isabel; Ibáñez García, María Isabel; de la Peña Moreno, Fernando; Sáez Melero, Lara Paloma; Luque-Almagro, Víctor Manuel; Castillo Rodríguez, Francisco; Roldán Ruiz, María Dolores; Prieto Jiménez, María Auxiliadora; Moreno Vivián, Conrado

    2015-06-10

    Cyanide is one of the most toxic chemicals produced by anthropogenic activities like mining and jewelry industries, which generate wastewater residues with high concentrations of this compound. Pseudomonas pseudoalcaligenes CECT5344 is a model microorganism to be used in detoxification of industrial wastewaters containing not only free cyanide (CN(-)) but also cyano-derivatives, such as cyanate, nitriles and metal-cyanide complexes. Previous in silico analyses suggested the existence of genes putatively involved in metabolism of short chain length (scl-) and medium chain length (mcl-) polyhydroxyalkanoates (PHAs) located in three different clusters in the genome of this bacterium. PHAs are polyesters considered as an alternative of petroleum-based plastics. Strategies to optimize the bioremediation process in terms of reducing the cost of the production medium are required. In this work, a biological treatment of the jewelry industry cyanide-rich wastewater coupled to PHAs production as by-product has been considered. The functionality of the pha genes from P. pseudoalcaligenes CECT5344 has been demonstrated. Mutant strains defective in each proposed PHA synthases coding genes (Mpha(-), deleted in putative mcl-PHA synthases; Spha(-), deleted in the putative scl-PHA synthase) were generated. The accumulation and monomer composition of scl- or mcl-PHAs in wild type and mutant strains were confirmed by gas chromatography-mass spectrometry (GC-MS). The production of PHAs as by-product while degrading cyanide from the jewelry industry wastewater was analyzed in batch reactor in each strain. The wild type and the mutant strains grew at similar rates when using octanoate as the carbon source and cyanide as the sole nitrogen source. When cyanide was depleted from the medium, both scl-PHAs and mcl-PHAs were detected in the wild-type strain, whereas scl-PHAs or mcl-PHAs were accumulated in Mpha(-) and Spha(-), respectively. The scl-PHAs were identified as homopolymers of 3

  8. Exploring the microbiota dynamics related to vegetable biomasses degradation and study of lignocellulose-degrading bacteria for industrial biotechnological application

    Science.gov (United States)

    Ventorino, Valeria; Aliberti, Alberto; Faraco, Vincenza; Robertiello, Alessandro; Giacobbe, Simona; Ercolini, Danilo; Amore, Antonella; Fagnano, Massimo; Pepe, Olimpia

    2015-02-01

    The aims of this study were to evaluate the microbial diversity of different lignocellulosic biomasses during degradation under natural conditions and to isolate, select, characterise new well-adapted bacterial strains to detect potentially improved enzyme-producing bacteria. The microbiota of biomass piles of Arundo donax, Eucalyptus camaldulensis and Populus nigra were evaluated by high-throughput sequencing. A highly complex bacterial community was found, composed of ubiquitous bacteria, with the highest representation by the Actinobacteria, Proteobacteria, Bacteroidetes and Firmicutes phyla. The abundances of the major and minor taxa retrieved during the process were determined by the selective pressure produced by the lignocellulosic plant species and degradation conditions. Moreover, cellulolytic bacteria were isolated using differential substrates and screened for cellulase, cellobiase, xylanase, pectinase and ligninase activities. Forty strains that showed multienzymatic activity were selected and identified. The highest endo-cellulase activity was seen in Promicromonospora sukumoe CE86 and Isoptericola variabilis CA84, which were able to degrade cellulose, cellobiose and xylan. Sixty-two percent of bacterial strains tested exhibited high extracellular endo-1,4-ß-glucanase activity in liquid media. These approaches show that the microbiota of lignocellulosic biomasses can be considered an important source of bacterial strains to upgrade the feasibility of lignocellulose conversion for the `greener' technology of second-generation biofuels.

  9. Decreasing activated sludge thermal hydrolysis temperature reduces product colour, without decreasing degradability.

    Science.gov (United States)

    Dwyer, Jason; Starrenburg, Daniel; Tait, Stephan; Barr, Keith; Batstone, Damien J; Lant, Paul

    2008-11-01

    Activated sludges are becoming more difficult to degrade in anaerobic digesters, due to the implementation of stricter nitrogen limits, longer sludge ages, and removal of primary sedimentation units. Thermal hydrolysis is a popular method to enhance degradability of long-age activated sludge, and involves pressure and heat treatment of the process fluid (150-160 degrees C saturated steam). However, as documented in this study, in a full-scale system, the use of thermal hydrolysis produces coloured, recalcitrant compounds that can have downstream impacts (e.g., failure of UV disinfection, and increased effluent nitrogen). The coloured compound formed during thermal hydrolysis was found to be melanoidins. These are coloured recalcitrant compounds produced by polymerisation of low molecular weight intermediates, such as carbohydrates and amino compounds at elevated temperature (Maillard reaction). By decreasing the THP operating temperature from 165 degrees C to 140 degrees C, THP effluent colour decreased from 12,677 mg-PtCo L(-1) to 3837 mg-PtCo L(-1). The change in THP operating temperature from 165 degrees C to 140 degrees C was shown to have no significant impact on anaerobic biodegradability of the sludge. The rate and extent of COD biodegradation remained largely unaffected by the temperature change with an average first order hydrolysis rate of 0.19 d(-1) and conversion extent of 0.43 g-COD(CH4)g-COD(-1).

  10. Only low methane production and emission in degraded peat extraction sites after rewetting

    Science.gov (United States)

    Agethen, Svenja; Waldemer, Carolin; Knorr, Klaus-Holger

    2015-04-01

    In Central Europe rewetting of bogs after peat extraction is a wide spread technique to halt secondary aerobic decomposition and to reestablish plant species such as Sphagnum spp. and Eriophorum spp. that initialize accumulation of organic carbon in peat. Before extraction, such sites are often used for agriculture causing the aerobic degradation of peat and mobilization of phosphorus, ammonia, and dissolved organic matter (DOM). In nutrient poor ecosystems such as bogs, additional supply of P and N does not only trigger the establishment of uncharacteristic vegetation but also the formation of more labile plant litter and DOM that is readily degradable. Therefore, after rewetting and the development of anoxic conditions especially in initial stages high methane (CH4) emissions are reported for these systems compared to pristine bogs. Regarding the potential of methane production and emissions we investigated three common practices to prepare extraction fields for restoration (years since rewetting): i) Filling of drainage ditches, passive rewetting (1 site, Altendorfer Moor, Stade, NW-Germany, ca. 20 yr.), ii) Removal of upper 30 cm peat layer, removed peat used for construction of polder dikes (2 sites, Königsmoor, Leer, NW-Germany, 2 and 3 yr.), iii) Removal upper peat layer down to 50 cm grown peat, not extracted peat used as polder walls (2 sites, Benthullener Moor, Wardenburg, NW-Germany, 3 and 7 yr.). In each site two vegetated replicate mesocosms (diam. 30 cm, depth 40 cm) were sampled and placed in a greenhouse from May-October 2014 to maintain the water table at surface level. Pore water concentrations of ions, fermentation products and DOM, DOM electron acceptor capacity (EAC), soil gas concentrations of CO2, CH4 and H2, gas fluxes as well as element composition and organic matter quality of DOM and SOM were analyzed. We found out that practice i) with least efforts of nutrient removal in the peat produced the highest CH4 emissions (3.5 mmol m-2 d-1

  11. Enhanced Agarose and Xylan Degradation for Production of Polyhydroxyalkanoates by Co-Culture of Marine Bacterium, Saccharophagus degradans and Its Contaminant, Bacillus cereus

    Directory of Open Access Journals (Sweden)

    Shailesh S. Sawant

    2017-02-01

    Full Text Available Over reliance on energy or petroleum products has raised concerns both in regards to the depletion of their associated natural resources as well as their increasing costs. Bioplastics derived from microbes are emerging as promising alternatives to fossil fuel derived petroleum plastics. The development of a simple and eco-friendly strategy for bioplastic production with high productivity and yield, which is produced in a cost effective manner utilising abundantly available renewable carbon sources, would have the potential to result in an inexhaustible global energy source. Here we report the biosynthesis of bioplastic polyhydroxyalkanoates (PHAs in pure cultures of marine bacterium, Saccharophagus degradans 2-40 (Sde 2-40, its contaminant, Bacillus cereus, and a co-culture of these bacteria (Sde 2-40 and B. cereus degrading plant and algae derived complex polysaccharides. Sde 2-40 degraded the complex polysaccharides agarose and xylan as sole carbon sources for biosynthesis of PHAs. The ability of Sde 2-40 to degrade agarose increased after co-culturing with B. cereus. The association of Sde 2-40 with B. cereus resulted in increased cell growth and higher PHA production (34.5% of dry cell weight from xylan as a carbon source in comparison to Sde 2-40 alone (22.7% of dry cell weight. The present study offers an innovative prototype for production of PHA through consolidated bioprocessing of complex carbon sources by pure and co-culture of microorganisms.

  12. Enhanced Agarose and Xylan Degradation for Production of Polyhydroxyalkanoates by Co-Culture of Marine Bacterium, Saccharophagus degradans and Its Contaminant, Bacillus cereus

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, Shailesh; Salunke, Bipinchandra; Taylor, Larry; Kim, Beom

    2017-02-28

    Over reliance on energy or petroleum products has raised concerns both in regards to the depletion of their associated natural resources as well as their increasing costs. Bioplastics derived from microbes are emerging as promising alternatives to fossil fuel derived petroleum plastics. The development of a simple and eco-friendly strategy for bioplastic production with high productivity and yield, which is produced in a cost effective manner utilising abundantly available renewable carbon sources, would have the potential to result in an inexhaustible global energy source. Here we report the biosynthesis of bioplastic polyhydroxyalkanoates (PHAs) in pure cultures of marine bacterium, Saccharophagus degradans 2-40 (Sde 2-40), its contaminant, Bacillus cereus, and a co-culture of these bacteria (Sde 2-40 and B. cereus) degrading plant and algae derived complex polysaccharides. Sde 2-40 degraded the complex polysaccharides agarose and xylan as sole carbon sources for biosynthesis of PHAs. The ability of Sde 2-40 to degrade agarose increased after co-culturing with B. cereus. The association of Sde 2-40 with B. cereus resulted in increased cell growth and higher PHA production (34.5% of dry cell weight) from xylan as a carbon source in comparison to Sde 2-40 alone (22.7% of dry cell weight). The present study offers an innovative prototype for production of PHA through consolidated bioprocessing of complex carbon sources by pure and co-culture of microorganisms.

  13. Enhanced production of raw starch degrading enzyme using agro-industrial waste mixtures by thermotolerant Rhizopus microsporus for raw cassava chip saccharification in ethanol production.

    Science.gov (United States)

    Trakarnpaiboon, Srisakul; Srisuk, Nantana; Piyachomkwan, Kuakoon; Sakai, Kenji; Kitpreechavanich, Vichien

    2017-09-14

    In the present study, solid-state fermentation for the production of raw starch degrading enzyme was investigated by thermotolerant Rhizopus microsporus TISTR 3531 using a combination of agro-industrial wastes as substrates. The obtained crude enzyme was applied for hydrolysis of raw cassava starch and chips at low temperature and subjected to nonsterile ethanol production using raw cassava chips. The agro-industrial waste ratio was optimized using a simplex axial mixture design. The results showed that the substrate mixture consisting of rice bran:corncob:cassava bagasse at 8 g:10 g:2 g yielded the highest enzyme production of 201.6 U/g dry solid. The optimized condition for solid-state fermentation was found as 65% initial moisture content, 35°C, initial pH of 6.0, and 5 × 10(6) spores/mL inoculum, which gave the highest enzyme activity of 389.5 U/g dry solid. The enzyme showed high efficiency on saccharification of raw cassava starch and chips with synergistic activities of commercial α-amylase at 50°C, which promotes low-temperature bioethanol production. A high ethanol concentration of 102.2 g/L with 78% fermentation efficiency was achieved from modified simultaneous saccharification and fermentation using cofermentation of the enzymatic hydrolysate of 300 g raw cassava chips/L with cane molasses.

  14. Ruminal degradability and intestinal digestibility of protein and amino acids in soybean and corn distillers grains products.

    Science.gov (United States)

    Mjoun, K; Kalscheur, K F; Hippen, A R; Schingoethe, D J

    2010-09-01

    New fractionation and fermentation technologies in the ethanol industry have resulted in the production of different forms of distillers grains (DG). Such products are reduced-fat, high-protein, and "modified" wet feeds. Characterization of protein fractions of these co-products and other commonly used feedstuffs is important for the formulation of dairy cattle diets. In situ and in vitro techniques were conducted to compare crude protein (CP) availability in 4 DG products with commonly used soybean proteins. Soybean protein products included solvent-extracted soybean meal (SBM; 44% CP), expeller soybean meal (ESBM), and extruded soybeans (ES). The DG products were conventional distillers dried grains with solubles, reduced-fat distillers dried grains with solubles (RFDGS), high-protein distillers dried grains, and modified wet distillers grains with solubles (MWDGS). Nylon bags containing 5 g of each feed were incubated in the rumen of 3 cannulated lactating cows for 2, 4, 8, 16, 24, and 48 h. The rapidly degradable CP fraction varied from 8.1 to 37.2% for SBM and MWDGS, respectively. The slowly degradable CP fraction was greatest for SBM, ES, and high-protein distillers dried grains (88.0%+/-3.7), followed by ESBM, distillers dried grains with solubles, and RFDGS (76.8+/-4.1%). The MWDGS had the lowest slowly degradable CP fraction (61.1%). The rate of degradation of the slowly degradable CP fraction ranged from 11.8 for SBM to 2.7%/h for RFDGS. Rumen-undegradable protein varied widely (32.3 to 60.4%), with RFDGS having the greatest and SBM the lowest concentrations. Intestinal digestibility of rumen-undegradable protein (IDP) was estimated by pepsin-pancreatin digestion of ruminally preincubated (16 h) samples. The IDP was greatest for SBM, ESBM, and ES (97.7%+/-0.75), whereas IDP of DG products was 92.4%+/-0.87. Similarly, total digestible protein was greatest (99.0%) for soybean products, whereas DG products had a total digestible protein of 96.0%. Intestinal

  15. Urinary collagen degradation products as early markers of progressive renal fibrosis.

    Science.gov (United States)

    Hijmans, Ryanne S; Rasmussen, Daniel Guldager Kring; Yazdani, Saleh; Navis, Gerjan; van Goor, Harry; Karsdal, Morten Asser; Genovese, Federica; van den Born, Jacob

    2017-03-20

    Renal fibrogenesis is associated with increased ECM remodeling and release of collagen fragments in urine in progressive renal disease. We investigated the diagnostic value of urinary collagen degradation products in a proteinuria-driven fibrosis rat model with and without anti-fibrotic S1P-receptor modulator FTY720 treatment. Proteinuria was induced in male Wistar rats by Adriamycin (ADR) injection (n = 16). Healthy rats served as controls (n = 12). Six weeks post-injection, all underwent renal biopsy, and FTY720-treatment started in ADR-rats (n = 8) and controls (n = 6). Others remained untreated. Rats were sacrificed after 12 weeks. Collagen type I (C1M) and III (C3M) degradation fragments were measured in blood and urine using ELISA. Kidneys were stained for various inflammatory and fibrotic markers. Six weeks post-injection proteinuria increased (versus controls, P < 0.001) and although no accumulation of interstitial renal collagen type III (iColl3) was observed at this time, urinary C3M (uC3M) and C1M (uC1M) were significantly increased (both P < 0.001). At 12 weeks, uC3M (P < 0.001) and uC1M (P < 0.01) further increased in ADR-rats versus controls, just as fibronectin, PDGF-β receptor, hyaluronan (all P < 0.01), iColl3, PAS, myofibroblasts, macrophages and T-cells (all P < 0.05). FTY720-treatment reduced accumulation of immune cells, α-SMA+ myofibroblasts and PAS-score, but not iColl3 and uC3M. Correlation analyses indicated that uC3M and uC1M reflected and predicted tubulointerstitial fibrogenesis. These data displayed urinary collagen breakdown products as sensitive early markers of interstitial fibrosis, preceding histological fibrotic changes, which might replace the invasive renal biopsy procedure to assess fibrosis. Anti-fibrotic FTY720 intervention reduced some fibrotic markers without affecting collagen type III metabolism.

  16. Simultaneous HPLC Determination of Chlordiazepoxide and Mebeverine HCl in the Presence of Their Degradation Products and Impurities

    Directory of Open Access Journals (Sweden)

    Rania N. El-Shaheny

    2015-01-01

    Full Text Available A simple, rapid, and sensitive RP-HPLC method was developed and validated for the simultaneous determination of chlordiazepoxide (CDO and mebeverine HCl (MBV in the presence of CDO impurity (2-amino-5-chlorobenzophenone, ACB and MBV degradation product (veratric acid, VER. Separation was achieved within 9 min on a BDS Hypersil phenyl column (4.5 mm × 250 mm, 5 µm particle size using a mobile phase consisting of acetonitrile: 0.1 M potassium dihydrogen phosphate: triethylamine (35 : 65 : 0.2, v/v/v in an isocratic mode at a flow rate of 1 mL/min. The pH of the mobile phase was adjusted to 4.5 with orthophosphoric acid and UV detection was set at 260 nm. A complete validation procedure was conducted. The proposed method exhibited excellent linearity over the concentration ranges of 1.0–100.0, 10.0–200.0, 2.0–40.0, and 2.0–40.0 µg/mL for CDO, MBV, VER, and ACB, respectively. The proposed method was applied for the simultaneous determination of CDO and MBV in their coformulated tablets with mean percentage recoveries of 99.75 ± 0.62 and 98.61 ± 0.38, respectively. The results of the proposed method were favorably compared with those of a comparison HPLC method using Student t-test and the variance ratio F-test. The chemical structure of MBV degradation product was ascertained by mass spectrometry and IR studies.

  17. Determination of atrazine and degradation products in Luxembourgish drinking water: origin and fate of potential endocrine-disrupting pesticides.

    Science.gov (United States)

    Bohn, T; Cocco, E; Gourdol, L; Guignard, C; Hoffmann, L

    2011-08-01

    Several pesticides have been hypothesized to act as endocrine-disrupting compounds, exhibiting hormonal activity and perturbing normal physiological functions. Among these, especially s-triazine herbicides have received increased attention. Despite being banned in many countries, including the European Union, atrazine is still the world's most widely used herbicide. Despite its discontinued use, considerable concentrations of atrazine and its degradation products, mainly desethylatrazine (DEA) and deisopropylatrazine (DIA), are still found in the environment, including drinking water sources. The aim of this investigation was to study concentrations of especially s-triazine herbicides and major degradation products in drinking water, including spring water, tap water and bottled water in Luxembourg. Spring water (2007/2008/2009, n = 69/69/69), tap water (2008/2009, n = 19/26), and bottled water (2007/2008/2009, n = 5/13/7) were sampled at locations in Luxembourg and investigated for pesticides by LC-ESI-MS/MS. Atrazine was the predominant triazine, detectable in many spring water locations, tap and bottled water, ranging (mean) from 0-57 (9), 0-44 (4), and 0-4 (1) ng l(-1), respectively. DEA and DIA in spring water ranged (mean) from 0-120 (19) and 0-27 (3) ng l(-1), with higher concentrations from agricultural areas and low molar ratios of DEA:atrazine high ratios of atrazine:nitrate suggesting point-source contamination. Levels (mean) of DEA and DIA in tap water were 0-62 (14) and 0-6 (water 0-11 (2) and 0-7 (2) ng l(-1). Simazine and other triazines were detected in traces (water, presumably partly due to non-agricultural contamination, with concentrations being below thresholds advocated by the European Union Directive 98/83/EC.

  18. Determination of IGF-1 and IGF-2, their degradation products and synthetic analogues in urine by LC-MS/MS.

    Science.gov (United States)

    Thomas, Andreas; Kohler, Maxie; Schänzer, Wilhelm; Delahaut, Philippe; Thevis, Mario

    2011-03-07

    Peptide analysis in doping controls by means of nano-UPLC coupled high resolution/high mass accuracy mass spectrometry provides the state-of-the-art technique in modern sports drug testing. The present study describes a recent application of this technique for the qualitative determination of different urinary insulin-like growth factor (IGF) related peptides. After simultaneous isolation by solid phase extraction and magnetic particle-based immunoaffinity purification, target analytes (IGF-1, IGF-2, Des1-3-IGF-1, R(3)-IGF-1 and longR(3)-IGF-1) were separated by nano-liquid chromatography prior to mass spectrometric detection. Endogenously produced IGF-1 and IGF-2, as well as the degradation product Des1-3-IGF-1, were frequently detected in urine samples from healthy volunteers in a concentration range of 20-400 pg mL(-1). The impact of IGF binding proteins (IGFBPs), being also present in urine, was potentially estimated by an additional ultrafiltration step in the sample preparation procedure. The synthetic analogue longR(3)-IGF-1, which is assumed to be subject to misuse by cheating athletes, was also analysed and detected in fortified urine samples. Besides the intact molecule, an N-terminally truncated degradation product Des1-10-longR(3)-IGF-1 was identified as the more stable target for doping controls using urine samples. The method was validated for qualitative purposes considering the parameters specificity, limit of detection (20-50 pg mL(-1)), recovery (10-35%), precision (<20%), linearity, robustness and stability.

  19. Fundamental Study on Coke Degradation in BF with Oxygen Enriched Blast and High Hydrogen Atmosphere

    Institute of Scientific and Technical Information of China (English)

    WANG Ping; LI Jia-xin; ZHOU Li-ying

    2005-01-01

    The effects of gas composition, temperature, ore to coke ratio and prereduction rate of ore on coke degradation were studied. The results showed that 1% increment in solution loss of coke reduces coke strength by 0.6%, and the coke degradation is accelerated with the temperature. The higher the temperature, the more coke surface is involved in reactions, and the less negative effect on coke strength is. Hydrogen exerts stronger effect on coke degradation than CO at high temperature. The coke degradation is decreased with the reduction of ore to coke ratio and increase of ore prereduction rate.

  20. Strategies to alleviate poverty and grassland degradation in Inner Mongolia: intensification vs production efficiency of livestock systems.

    Science.gov (United States)

    Briske, David D; Zhao, Mengli; Han, Guodong; Xiu, Changbai; Kemp, David R; Willms, Walter; Havstad, Kris; Kang, Le; Wang, Zhongwu; Wu, Jianguo; Han, Xingguo; Bai, Yongfei

    2015-04-01

    Semi-nomadic pastoralism was replaced by sedentary pastoralism in Inner Mongolia during the 1960's in response to changes in land use policy and increasing human population. Large increases in numbers of livestock and pastoralist households (11- and 9-fold, respectively) during the past 60 yrs have variously degraded the majority of grasslands in Inner Mongolia (78 M ha) and jeopardize the livelihoods of 24 M human inhabitants. A prevailing strategy for alleviating poverty and grassland degradation emphasizes intensification of livestock production systems to maintain both pastoral livelihoods and large livestock numbers. We consider this strategy unsustainable because maximization of livestock revenue incurs high supplemental feed costs, marginalizes net household income, and promotes larger flock sizes to create a positive feedback loop driving grassland degradation. We offer an alternative strategy that increases both livestock production efficiency and net pastoral income by marketing hig