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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Modélisation du devenir des micropolluants organiques au cours de la digestion anaérobie de boues contaminées / Modeling the fate of micro ollutant organics during anaerobic digestion of contaminated sewage sludge

Delgadillo Mirquez, Liliana Rocio 02 December 2011 (has links)
Beaucoup de micropolluants organiques sont présents dans les boues. Leur possible impact sur l'environnement contribue à accroître leur intérêt scientifique et social. La digestion anaérobie présente un potentiel certain pour dégrader ces composés. Dans ce travail, il a été développé un modèle dynamique pour décrire le devenir de micropolluants hydrophobes au cours de la digestion anaérobie de boues contaminées. Le modèle est basé sur une distribution des composés dans quatre-compartiments et il a démontré que la transformation des micropolluants est bien simulée si l'on considère une cinétique de co-métabolisme pour la dégradation et si la phase aqueuse constitue le compartiment biodisponible. Dans ce modèle, la sorption des micropolluants hydrophobes est envisagée sur deux phases différentes: la matière particulaire et la matière dissoute/colloïdale (DCM), car la sorption sur le compartiment DCM peut influencer la disponibilité des composés et donc leur biodégradation. Il a été conclu que le transfert de micropolluants hydrophobe ne limite pas leur biodégradation, et que leur devenir est régi par l'état d'équilibre de sorption-désorption. Afin d'identifier quelle(s) étape(s) de la digestion permet le co-métabolisme, de nouvelles expérimentations ont été menées en utilisant des inhibiteurs des Méthanogènes. Elles suggèrent que la dégradation anaérobie des micropolluants implique principalement des microorganismes non-méthanogènes. En effet, la transformation co-métabolique des micropolluants serait principalement liée à la population acidogènes, comme le montre le modèle avancé proposé. Le modèle proposé est potentiellement utile pour mieux comprendre la distribution des micropolluants, prédire leur devenir dans des conditions anaérobies et aider à optimiser le processus de fonctionnement pour leur épuisement. / Many organic micropollutants are present in sludge. Their possible impact on the environment contributes to their increasing scientific and social interest. Anaerobic digestion has been shown as a potential biological process for removing these compounds. In this work, a dynamical fate model is developed for hydrophobic micropollutant under anaerobic digestion of contaminated sludge. The model is based on a four-compartment distribution and demonstrated that the micropollutant transformation is well simulated if considering a co-metabolic kinetic and the aqueous phase as the bioavailable compartment. In this model, the sorption of hydrophobic micropollutants is considered on two different phases: particulate matter and dissolved/colloidal matter (DCM). Indeed, the sorption onto DCM can influence the availability of compounds for biodegradation. It was concluded that hydrophobic micropollutant transfer does not limit their biodegradation, and that their fate is governed by sorption-desorption equilibrium state. In order to evaluate which step of the anaerobic pathway is implied in the co-metabolism of micropollutants, experimental set-ups were designed using different way to inhibit the Methanogens. The experimental inhibition of methanogenic activity suggests that the anaerobic degradation of micropollutants mainly involves non-methanogenic microorganisms. Indeed, the co-metabolic transformation of micropollutants would be mainly linked to acidogens population as it was shown through the proposed advanced model. This latter is potentially useful to better understand the micropollutant distribution, predict their fate under anaerobic condition and help to optimize the operation process for their depletion.
22

Simulation of the diffusion of endocrine disrupting compounds in silicalite by molecular dynamics

Gabry, Thomas Jacques Andre 26 April 2012 (has links)
In this thesis we investigated the separation of two endocrine disrupting chemicals (EDC), bisphenol-A (BPA) and nonylphenol (NP) from water over the defect free silicalite zeolite. Two force-fields were investigated, the OPLS-AA force-field which is an all-atom one, and the OPLS-UA force-field which is a united atom one. In order to be able to simulate BPA, we simulated and studied the diffusion of different molecules in silicalite. We compared two famous bulk water models, the non-rigid TIP3P modified for CHARMM model and the rigid SPC model, to literature and simulated the diffusion of these water molecules at temperatures from 300K to 600K. We found that these models coupled with our parameters for silicalite compared poorly with literature except for values calculated by Yazaydin et al. The mean-square displacements (MSDs) were more important in the x-direction (sinusoidal channel) than in the expected y-direction (straight channels) for both models resulting in small self-diffusion coefficient values. Results tended to improve as temperature increased. We believe that the high number of hydrogen bonds, implying the presence of clusters of water molecules, is responsible for the poor self-diffusion coefficient. The charges chosen to describe our silicalite zeolite, +2.05, may also be a reason of our small self-diffusion coefficient. We then investigated the self-diffusion of aromatic molecules at 300 and 400K. Benzene, phenol and toluene were studied. We found self-diffusion coefficients for benzene that did not compare well to experiments but that was close to simulation work done by Rungsirisakun et al. Our diffusion coefficients for benzene were several orders of magnitude bigger than the experimental values found in literature for both force-fields. The diffusion patterns for both phenol and toluene did not allow us to calculate self-diffusion coefficients for both investigated force-fields. We believe that the jumps in the MSDs of these molecules are due to the rotation that they undergo in the nanopores. Phenol anchors to the framework by hydrogen-bonds between the hydrogen of its alcohol group and the oxygen of the framework. The diffusion seems to happen when the alcohol group is in a line with one channel. The same diffusion phenomenon was seen for toluene molecule but was related to the methyl group attached to its benzene ring. When this group is in front of a channel, the energetic barrier is reduced and the molecule can diffuse through it. Finally bigger molecules were simulated and studied. Neopentane seemed to have a very low self-diffusion coefficient in silicalite if it could move at all. We report values of self-diffusion of 1.3 10-14 m2.s-1 at both 300K and 400K. This value seems a little high compared to benzene experimental self-diffusion coefficient values that are in the same order of magnitude at both temperatures. The linear nonylphenol molecule that we simulated seemed to diffuse through silicalite with patterns that were close to the one seen for phenol. The hydrogen bonding between its alcohol group and the framework slows down its diffusion in silicalite. With the same reasoning as for phenol we decided not to calculate diffusion coefficient for NP. The last molecule investigated was bisphenol-A (BPA). We found that BPA almost did not diffuse through silicalite. The size of the molecule can explain why it did not diffuse, but we believe that the angle between the two phenol groups should be able to bend enough for it to diffuse, slowly, through silicalite. Our conclusion is that the two phenol groups at both ends of the molecules are the most important factor in its very slow diffusion. Hydrogen bonding is taking place at both ends making it very hard for the molecule to move in the framework. We decided to generate self-diffusion coefficients for this molecule because the diffusion process did not have jumps. We found self-diffusion coefficient that are 3.10-15 m2.s-1 and 15. 10-15 m2.s-1 at 300 and 400K respectively for the OPLS-AA force-field, and 11.6.10-15 m2.s-1 and 6.68.10-15 m2.s-1 at 300 and 400K respectively for the OPLS-UA force-field. The last result was unexpected as we thought that the self-diffusion coefficient was going to increase with temperature. We believe that running much longer simulations for every molecule that we studied should give more reasonable and reliable results as the self-diffusion coefficients values are very small.
23

Environmental Risk Assessment of Nonylphenol Spillage in Göta Älv

Arbaban Esfahani, Elham January 2008 (has links)
Environmental concern due to handling of hazardous chemicals is growing. This issue drawsstakeholder attentions more than before to risks associated with accidental spillage in industryor traffic. This study aims at addressing the risks resulting from the spillage of one metrictonne nonylphenol from an imaginary traffic accident.The environmental risk assessment approach outlined in this study attempts to address theconcern for the potential impact of hazardous substances on the environment by examiningboth exposures and effects of such incidents on the structure and function of the ecosystem.Nonylphenol has been selected as the discharged contaminant in this thesis for these reasons.It is an organic liquid with low vapour pressure. It is not produced in Sweden. About 2400tonnes are imported yearly. It is mainly used for making nonylphenol ethoxylates, which havea wide use as detergents, emulsifiers, lubricants and additives in a variety of industries. It isreleased from the ethoxylates in waste water. There are some published reports on its toxicityas well as endocrine property to species.In this study the exposure concentrations are predicted through developing a multimedia fateexposuremodel for the Göta älv fresh water ecosystem. It is a dynamic version of QMXfugacitymodel applicable for river basins. This fate model is integrated with a simplified foodweb model in order to quantify the extent of nonylphenol concentration in organisms.Moreover the dose response correlation derived from the most validated experimental studiesis utilized to estimate Predicted No Effect Concentration for aquatic ecosystem.The probability of accidental spillage of nonylphenol is extremely low and is not part of thisstudy. On the other hand the consequence of spillage affecting the ecosystem is treated fromseveral aspects, mainly by using the PEC/PNEC ratio. In the aquatic ecosystem pelagic (freewater) and benthic (bottom zone) organisms are studied.Estimated risk concerning the spillage suggests that acute toxicity among pelagic organisms isplausible up river especially in the Trollhättan region. However sub-lethal effects such asreproduction and growth inhibition will probably be observed all along the river with mostconcern in up river. In the sediment phase the benthic organisms are shown to be put at riskfor a prolonged period of time and organisms may suffer from chronic toxicity. In addition thesediment acts as a sink for contaminant with potential release of the hazardous substance.However, it is difficult to predict a full extent of adverse consequences. But it seems that sublethaleffects on benthos and consequent side effects on other populations should beconcluded as the most important direct consequence of a nonylphenol spillage. / Uppsatsnivå: D
24

Accumulation and effects of 4-nonylphenol in chinook salmon fry and their estuarine amphipod prey

Hecht, Scott A. 09 August 2002 (has links)
4-nonylphenol (NP), a surfactant degradation product, is an unregulated, ubiquitous aquatic contaminant and endocrine disruptor, for which aquatic life criteria are currently under development by U.S. EPA. The effects of NP on estuarine amphipods and chinook salmon fry were investigated, and this dissertation reports research into the impacts of NP bioaccumulation on the amphipods and resultant endocrine disruption of their juvenile salmon predators. Sensitivity to, and bioaccumulation of, NP by benthic amphipods were quantified. Factors affecting the bioavailability of NP to three species of amphipod (Eohaustorius estuarius, Grandidierella japonica, and Corophium salmonis) were determined in contaminated sediments. Standard bioassay techniques were modified to determine toxicity and bioaccumulation, with varying amounts and differing nutritional qualities of sedimentary organic carbon. �����C-Ring-labeled NP was used as a tracer in the experiments to quantify amphipod exposures. NP was acutely toxic to Eohaustorius estuarius from aqueous exposures, mean (+/-SD) LC50=227 ��g/L +/- 56, 1 h mean reburial EC50=138 +/- 36. The predicted LC50 for NP (202 ��g/L) from an amphipod-derived structure-activity relationship was not significantly different (p>0.05) from our empirically derived LC50 (227 ��g/L). All three amphipod species accumulated significant NP body burdens. Accumulation was inversely proportional to the total amount of organic carbon, but it did not differ between types of organic matter. Calculated accumulation factors indicated that amphipods could be an important and previously unrecognized source of NP to higher trophic levels. Plasma vitellogenin (Vtg) was quantified in juvenile chinook salmon following dietary exposure to NP contaminated amphipods and aqueous exposure to multiple NP concentrations. Fry that had fed upon contaminated amphipods did not have significantly greater Vtg levels than controls; however, Vtg was detected in 30 percent of fry. NP aqueous concentrations at 60 and 240 ��g/L significantly induced Vtg in fry following 5 d exposures. The 240 ��g/L aquatic NP treatment fry had comparable levels of Vtg to the positive control treatment in which fry were injected 17B-estradiol. These results indicate that amphipods are potential vectors of sediment NP to higher trophic levels within the water column, including juvenile chinook salmon. / Graduation date: 2003
25

Elimination des perturbateurs endocriniens nonylphénol, bisphénol A et triclosan par l'action oxydative de la laccase de coriolopsis polyzona

Cabana, Hubert 04 April 2008 (has links)
Les substances perturbatrices du système endocrinien sont des substances qui, de par leur capacité à induire des changements hormonaux chez les organismes vivants, génèrent des préoccupations dans le domaine de la qualité des eaux et, par extension, dans le domaine du traitement des effluents aqueux. Particulièrement, ce projet de recherche s’est attardé sur l’élimination des perturbateurs endocriniens phénoliques nonylphénol (NP), bisphénol A (BPA) et triclosan (TCS) en solution aqueuse à l’aide de la laccase (E.C. 1.10.3.2) sécrétée par la souche fongique Coriolopsis polyzona. Cette oxydase est une métalloprotéine pouvant catalyser l’oxydation d’une vaste gamme de substances phénoliques. En premier lieu, l’impact du pH et de la température sur l’élimination de ces composés à l’aide de la laccase libre en utilisant un design factoriel. L’oxydation de ces composés produit des oligomères (dimère à pentamère) via le couplage des radicaux phénoxy produits par l’action de la laccase. Il s’avère que les substances produites suite à l’oxydation du NP et du BPA par la laccase ont perdu leurs similitudes structurales avec l’estrogène. Ainsi, l’élimination de l’activité estrogénique de ces substances est directement liée à la transformation des composés. Finalement, l’utilisation d’ABTS comme médiateur a permis d’augmenter le taux d’oxydation enzymatique de ces composés chimiques. Puis, de façon à augmenter la possibilité d’utilisation de la laccase dans des biotechnologies environnementales, cette enzyme a été immobilisée sur un support siliceux et via la réticulation d’agrégats. L’impact des conditions d’immobilisation sur l’activité enzymatique, la stabilité du catalyseur et les propriété biocatalytiques apparentes a été déterminé pour différentes stratégies d’immobilisation. Globalement, l’immobilisation génère un biocatalyseur stable vis-à-vis les dénaturations chimique, physique et biologique. Particulièrement, l’immobilisation sur un support solide produit un biocatalyseur facile à utiliser ayant une faible activité massique et des propriétés cinétiques moindres que celle de l’enzyme libre. La formation de CLEAs de laccase a permis d’obtenir une activité massique élevée et des propriétés cinétiques supérieures à celle de l’enzyme soluble. Ces biocatalyseurs solides ont étés utilisés pour éliminer en continu le NP, BPA et TCS dans différents types de bioréacteur. Le biocatalyseur sur silice a été utilisé pour éliminer ces substances dans un réacteur garni, tandis que les CLEAs ont été utilisés dans un réacteur à lit fluidisé et un réacteur à perfusion développé au cours de ce projet. Ces différentes configurations de bioréacteur ont permis d’éliminer efficacement ces différents perturbateurs endocriniens. Globalement, les différents résultats obtenus, à l’échelle de laboratoire, au cours de ce projet de recherche démontrent que la laccase et particulièrement les biocatalyseurs formés via les différentes stratégies d’immobilisation testées représentent des approches extrêmement prometteuses pour le développement de biotechnologies environnementales vouées à l’élimination des perturbateurs endocriniens phénoliques.
26

The effect of nonylphenol and bisphenol A on calcium signaling and viability in cultured cells

Kuo, Chun-Chi 23 June 2010 (has links)
Environmental chemicals may affect human health by disrupting endocrine function. Many of the endocrine disrupting chemicals (EDCs) are estrogens or estrogen-like molecules that have been classified as environmental estrogens or xenoestrogens (XEs). XEs include endosulfan, chlordance, nonylphenol, bisphenol A, octylphenol, and coumestrol, etc. Although these compounds have wide structural diversity, but all have in common the and/or other hydrophobic components. Many studies have shown that XEs affect cell viability. For instance, Nonylphenol is used in surfactants or plasticizers and bisphenol A (4, 4¡¦-isopropylidene-2-diphenol) is used as protective coatings on food containers and for composites and sealants in dentistry. Most previous studies have focused on the toxicity of XEs on development process and reproductive system, especially in aquatic ecosystems. Thus, the effects of these two environmental chemicals on the toxicological effect are still controversial. The aim of this study is to investigate the molecular mechanisms of nonylphenol and bisphenol A in induction of cell death in human gastric cancer (SCM-1) cells and Madin Darby canine renal tubular (MDCK) cells. First, WST-1 reduction assays and propidium iodide-staining assay were used to determine cell viability and apoptosis in the present of nonylphenol and bisphenol A. Furthermore, we will use immunoblotting to measure the activity of apoptotic markers caspase-3, mitogen-activated protein kinases (MAPKs) to survey how nonylphenol affects apoptotic pathways. Besides, I will explore bisphenol A whether induces cell death and the mechanisms underlying the [Ca2+]i rise in MDCK cells. The results may be helpful for understanding the pharmacological and toxicological effects of these two environmental chemicals in cells from important organs. Results showed that nonylphenol caused apoptosis via the activation of caspase-3 in cultured human gastric cancer (SCM-1) cells. Although nonylphenol could activate the phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK), only SB203580 (a p38 MAPK inhibitor) partially prevented cells from apoptosis. Nonylphenol was also found to induce [Ca2+]i increases and pretreatment with BAPTA/AM, a Ca2+ chelator, prevented nonylphenol-induced [Ca2+]i increases, and protect cells from death. These results suggest that nonylphenol induced apoptosis via a Ca2+- and p38 MAPK-dependent pathway. On the other hand, the effect of the environmental contaminant bisphenol A on cytosolic free Ca2+ concentrations ([Ca2+]i) in Madin Darby canine kidney (MDCK) cells is unclear. This study explored whether bisphenol A changed basal [Ca2+]i levels in suspended MDCK cells by using fura-2 as a Ca2+-sensitive fluorescent dye. Bisphenol A at concentrations between 50-300 £gM increased [Ca2+]i in a concentration-dependent manner. The Ca2+ signal was reduced partly by removing extracellular Ca2+. Bisphenol A induced Mn2+ influx, leading to quench of fura-2 fluorescence suggesting Ca2+ influx. This Ca2+ influx was inhibited by phospholiapase A2 inhibitor aristolochic acid, store-operated Ca2+ channel blockers nifedipine and SK&F96365; and protein kinase C inhibitor GF109203X. In Ca2+-free medium, pretreatment with the mitochondrial uncoupler carbonylcyanide m-chlorophenylhydrazone (CCCP) and the endoplasmic reticulum Ca2+ pump inhibitors thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) inhibited bisphenol A-induced Ca2+ release. Conversely, pretreatment with bisphenol A abolished thapsigargin (or BHQ)- and CCCP-induced [Ca2+]i rise. Inhibition of phospholipase C with U73122 abolished bisphenol-induced [Ca2+]i rise. Bisphenol A caused concentration-dependent decrease in cell viability via apoptosis in a Ca2+-independent manner. Collectively, in MDCK cells, bisphenol A induced [Ca2+]i rises by causing phospholipase C-dependent Ca2+ release from the endoplasmic reticulum and mitochondria and Ca2+ influx via phospholipase A2-protein kinase C-sensitive store-operated Ca2+ channels. Key words: calcium, apoptosis, human gastric cancer cells (SCM-1), Madin Darby canine kidney (MDCK), nonylphenol, bisphenol A.
27

Determination of alkylphenol polyethoxylates in environmental water by liquid chromatography-tandem mass spectrometry

Lan, Yi-wen 19 August 2011 (has links)
A LC-MS/MS method for the analysis of alkylphenol polyethoxylates in environmental waters was developed in this study. Preatment procedures including liquid-liquid extraction and solid phase extraction were compared, it¡¦s concluded that solid phase extraction is the more suitable way due to higher recovery and better stability for the analytical results. The recovery of nonylphenol polyethoxylate and octylphenol polyethoxylate were 62.3-110.7 % and 64.9-112.0 %, limit of detection were 17.60-174.9 ng/L and 7.40-53.56 ng/L. Enviromental water samples were collected from eight sampling sites along Love River in Kaohsiung City to investigate the contents of alkylphenol polyethoxylates. The highest concentration of total alkylphenol polyethoxylates was observed at Ming-Cheng Bridge which located at the upstream of Love River. For all of the analyzed compounds, the concentration of octylphenol tetraethoxylate (40.46 £gg/L) was the highest in all of the sampling sites. It¡¦s also noticed the concentration of octylphenol polyethoxylate (20.11 £gg/L) was higher than that of nonylphenol polyehtoxylate (128.04 £gg/L).
28

Investigation of alkylphenol polyethoxylates in the aquatic environment of Hengchun peninsula

Chao, Ching-hung 07 September 2012 (has links)
In April and June 2012, environmental water samples were collected from fourteen sampling sites in Hengchun peninsula to investigate the contents of alkylphenol polyethoxylates. A solid phase extraction combined with LC-MS/MS method for the analysis of alkylphenol polyethoxylates in environmental waters was developed in this study. The mobile phase used methanol gradient elution with deionized water. The recovery of nonylphenol polyethoxylate and octylphenol polyethoxylate were 68~94 % and 65~93 %, limit of detection were 1.89~54.20 ng/L and 0.44~39.31 ng/L, limit of quantitative were 6.29~181 ng/L and 1.48~131 ng/L. The SsuChung river contents of NPEO and OPEO were 15.64~36.29 £gg/L and 3.14~7.37 £gg/L. The Paoli river contents of NPEO and OPEO were 16.65~76.41 £gg/L and 5.66~18.80 £gg/L. The Hou Bay contents of NPEO and OPEO were 34.79~66.72 £gg/L and 7.77~19.03 £gg/L. The Shihniou river contents of NPEO and OPEO were 26.67 £gg/L and 6.68 £gg/L. The Wanli Tong, Baisha, Houbi Lake, South Bay, Caesar and Siangjiao Bay contents of NPEO and OPEO were 14.17~48.82 £gg/L and 3.88~14.79 £gg/L. The dry season concentration contents of alkylphenol polyethoxylates were high than the wet season. The concentration of nonylphenol polyethoxylate was higher than that of octylphenol polyehtoxylate.
29

From chlorinated transformation products to highly hydrated ions with electrospray ionization mass spectrometry

Pape, Jennifer Lynn 26 May 2011 (has links)
Pharmaceutical and personal care products (PPCPs) triclosan and nonylphenol, were investigated throughout wastewater treatment in a publicly owned treatment works (POTW). Both compounds react quickly upon chlorination under laboratory conditions, transforming into mono and dichlorinated species. A novel quantitative analytical method employing mass spectrometry was demonstrated on Delaware POTW wastewater samples. Specific transformation products were not detected and the concentration of precursor analytes was not found to be statistically different after treatment. Under tertiary chlorination conditions, transformation products are not produced. ESI-MS was used to explore triply charged, highly hydrated lanthanide ions and charge reduction was directly observed in the MS collision cell. This process proceeded via proton transfer, proved by a strong correlation between the minimum number of water molecules required to stabilize the Ln3+ and the first hydrolysis constant (R2=0.92). The effect of different solvents on the surface activity of ions under electrospray ionization (ESI) was investigated using dilute ionic liquids and the relative surface activity of a given pair of ions could be reversed by moving from a relatively polar solvent to a relatively non-polar one. / Graduate
30

Nonylphenol activates the constitutive androstane receptor and causes sexually dimorphic changes in P450 expression

Hernandez, Juan Pablo. January 2008 (has links)
Thesis (Ph. D.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

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