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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.
231

Volatile organic compounds from microorganisms : identification and health effects

Claeson, Anna-Sara January 2006 (has links)
Damp building materials are subjected to degradation processes due to moisture and also microbial growth, with both of these giving rise to emissions of volatile organic compounds (VOCs) that may contribute to indoor air health problems. The overall aim of this thesis was to investigate emissions of reactive and non-reactive VOCs from damp building materials and from the microorganisms growing on them, and also to investigate the possible health impact of these compounds. Three studies were carried out in order to study emissions of VOCs. The first investigated emissions from a mixture of five fungi (Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi) and the second emissions from the bacterium Streptomyces albidoflavus. In both studies the microorganisms were cultivated on three different building materials (pine wood, particle board and gypsum board) and one synthetic media, MEA and TGEA respectively. The bacterium was also cultivated on sand. Air samples from the cultures were collected on six different adsorbents and chemosorbents to sample a wide range of compounds such as VOCs, aldehydes, amines and light-weight organic acids. The samples were analyzed with gas chromatography, high-pressure liquid chromatography and ion chromatography. Mass spectrometry was used for identification of the compounds. Alcohols and ketones were the predominant compound groups identified. The bacterial culture growing on TGEA emitted ammonia, methylamine, diethylamine and ethylamine. The third study dealt with secondary emissions collected from buildings with moisture and mould problems. Samples were taken when the materials were dry and also after they had been wet for a week. Most alcohols and ketones could be identified from the wet materials. Trimethylamine and triethylamine, were identified from sand contaminated by Bacillus. One study looked at the development of a method for analysis of primary and secondary amines with LC-MS/MS. A three-step process was developed, with the first step screening the samples for NIT derivatives with selected reaction monitoring, SRM. In the second step a precursor ion scan gave the [M+H]+ ion, and the last step involved fragmentation with a product ion scan. It was possible to separate and identify all the investigated amines, which showed that the method was both specific and selective and therefore well suited for the analysis of amines in complex environments. The last study comprised two exposure studies. In study 1 each participant took part in two exposure conditions, one with air from mouldy building materials and one with blank air for a 60 minute period. In study 2 each participant was exposed four times (for a period of 10 min) at random to air from mouldy building materials and blank air, with and without nose-clip. The participants rated air quality and symptoms before, during and after each exposure. Exposure to moderate VOC levels resulted in reports of perceived poor air quality, but no such results were received when exposing the participants to low VOC levels.
232

Étude de l'applicabilité des POCIS (Polar Organic Chemical Integrative Sampler) au dosage des résidus de médicaments dans les effluents hospitaliers

Bailly, Emilie 08 April 2013 (has links) (PDF)
L'évaluation des risques environnementaux et sanitaires liés à la présence de résidus de médicaments dans l'environnement, représente un enjeu majeur en particulier au regard de la gestion du cycle des usages de l'eau. Les effluents des établissements de soins représentent une source non négligeable de pollution et justifient le développement de techniques spécifiques de mesures des émissions de résidus de médicaments dans leurs eaux usées. Dans le cadre de ces développements de méthode, l'échantillonnage représente une des difficultés majeures car la matrice brute des eaux en sortie des hôpitaux est très chargée en matières organiques, les débits sont extrêmement variables, les sites de prélèvement sont difficiles d'accès et il existe une forte variabilité des dispensations des traitements jour/nuit et semaine/week-ends. Les échantillonneurs intégratifs apparus récemment, offrent une alternative intéressante aux stratégies d'échantillonnage existantes, permettant d'effectuer un suivi moyenné sur de longues périodes d'observation associé à une simplicité d'usage et une réduction des coûts. Ce travail porte sur l'étude de l'applicabilité des échantillonneurs intégratifs POCIS (Polar Organic Chemical Integrative Sampler) au dosage des résidus de médicaments dans les effluents hospitaliers. Ce dispositif a principalement été utilisé dans les eaux de surface et les effluents de STEP et son application dans les eaux usées reste rare. 6 molécules déjà identifiées comme représentatives des grandes familles de médicaments utilisés à l'hôpital (Aténolol, Prednisolone, Méthylprednisolone, Sulfaméthoxazole, Ofloxacine, Kétoprofène) ont été retenues.Les cinétiques d'adsorption des molécules sur les POCIS ont été suivies en laboratoire en condition de maitrise des paramètres les plus influents : température, vitesse de l'eau, charge en matière organique, colmatage...Ce calibrage a pour but de déterminer le coefficient d'échantillonnage Rs (L/j) spécifique à chaque molécule et nécessaire au calcul de la concentration dans le milieu d'exposition du POCIS. Nous avons observé une augmentation des Rs quand la vitesse de l'eau augmente ou quand la température augmente. Dans les eaux usées, la valeur de Rs est plus faible et la durée de la phase linéaire est réduite comparée à l'eau du robinet. Pour ce type d'application, la période d'exposition ne devra pas dépasser 4 à 5 jours en raison du colmatage des membranes et d'une teneur élevée en particules organiques dissoutes. Après calibrage dans l'eau du robinet et dans l'eau usée, les POCIS ont été exposés in situ dans un effluent hospitalier pour mesurer les concentrations en 6 molécules ciblées. Cinq ont pu être quantifiées et les concentrations calculées à partir des extraits des POCIS sont concordantes avec celles obtenues par prélèvement direct d'un échantillon moyenné d'eaux usées. Le facteur limitant réside dans les difficultés d'accès au site et la présence de solides dans le collecteur d'eaux usées. Ce travail ouvre des perspectives quant à l'application des POCIS pour les effluents hospitaliers et pourra à terme contribuer à l'acquisition de données pour une meilleure surveillance des rejets.
233

The Cyanotoxin Anatoxin-a: Factors Leading to its Production and Fate in Freshwaters

Gagnon, Alexis 08 February 2012 (has links)
Anatoxin-a (ANTX) is a neurotoxin produced by several freshwater cyanobacteria and has been implicated in the death of livestock and domestic animals from consumption of tainted surface waters. ANTX is unstable under normal conditions and is somewhat problematic to extract and study. Accelerated solvent extraction (ASE) combined with liquid chromatography-mass spectrometry (LC/MS) was used to develop an efficient extraction and analytical method for both ANTX and the more commonly encountered hepatotoxic microcystins produced by cyanobacteria. The effects of nitrogen supply on the cellular production and release of ANTX was investigated in Aphanizomenon issatschenkoi (Ussaczew) Proschkina-Lavrenko (Nostocales). In contrast to the predictions of the carbonnutrient balance hypothesis, the maximum production was observed under moderate N stress. In addition, steady state fugacity-based models were employed to investigate ANTX’s distribution and fate in freshwater ecosytems. ANTX was not found to be very persistent in aquatic ecosystems and did not appear to bioaccumulate in fish, at least not from the dissolved phase.
234

Aplicación de membrana de nanofiltración para eliminar disruptores endocrinos en la potabilización del agua

Abi-Faiçal Castanheira, Ana Paula 19 November 2010 (has links)
Muchas de las actividades humanas contribuyen al deterioro del medio ambiente debido a la gran variedad de residuos químicos vertidos. Algunas de estas sustancias químicas son bastante persistentes y causan serios efectos en los animales y en la salud humana en un largo período de tiempo, incluso cuando están presentes en concentraciones muy bajas (Kuramitz et al, 2002), como ocurre con los disruptores endocrinos (DEs). Un disruptor endocrino (DE), conforme a la definición de la Comisión de las Comunidades Europeas, es una sustancia exógena o una mezcla que altera la(s) función(es) del sistema endocrino y consecuentemente causa efectos adversos a la salud en un individuo o en su descendencia o en parte de la población (CEC, 1999). Como efectos adversos a la salud, los estudios médicos han demostrado en los últimos años un deterioro en la capacidad reproductiva humana en los países más industrializados; un aumento en la incidencia de alteraciones en el desarrollo de los órganos genitales; la aparición de la menstruación en edades cada vez más precoces (menarquia precoz); mayor frecuencia de la endometriosis; y el cáncer en los órganos que dependen de las hormonas, como es el caso de la mama, de la próstata, del testículo y del ovario. A propósito, el cáncer de ovario es una de las principales causas de mortandad en el mundo occidental (Aranda, 2004). Debido a la actividad estrogénica, tanto los detergentes como los esteroides han sido incluidos en las diversas listas preliminares de los compuestos DEs. El nonilfenol (NP) (compuesto sintético que posee actividad estrogénica, actúa como DE y es ampliamente usado como materia bruta para la fabricación de detergentes, anti-oxidantes de plástico, pesticidas y como un agente suplementario y estabilizador del cloruro de polivinilo (PVC) (Kuramitz et al, 2002)) ha sido clasificado como sustancia peligrosa prioritaria en el campo de la política del agua por la Estructura Directiva del Agua de la Comunidad Europea 2000/60/EC y por la decisión final de la Unión Europea nº 2455/2001/EC. La Directiva 2008/105/CE establece que el NP deberá presentar, como valor medio anual máximo, la concentración de 0,3 μg/L y como concentración máxima admisible, el valor de 2,0 μg/L, tanto para las aguas superficiales continentales como para otras aguas superficiales. La Agencia de Protección Ambiental (EPA, 2006) establece, en el criterio de calidad del agua, los valores límites de concentración de NP en agua dulce: 28 μg/L (a corto plazo) y de 6,6 μg/L (media de 4 días), para proteger la vida acuática de los efectos adversos. La estrona (E1) (estrógeno natural, excretado por el hombre y por la mujer a través de la orina y de los excrementos, está presente en muchas aguas y efluentes domésticos, presenta alta persistencia en el ambiente y alto potencial como DE (Schäfer and Waite, 2002)) está en la lista nº 3 de contaminantes químicos (CCL 3 List) de la EPA (2001), pero no existen reglamentaciones que limiten la concentración de este contaminante en el agua. Lo que existe es una indicación de que concentraciones de E1, en el rango entre 0,01 y 0,10 μg/L, ejercen efectos estrogénicos en peces (Routledge et al., 1998; Petrovic et al., 2004). Como la cuestión de la contaminación del agua por los DEs es un problema emergente y muy grave, por la perturbación que provoca en el sistema hormonal humano, el objetivo de este trabajo es comparar la eficiencia de la eliminación del NP y de la E1 de las aguas superficiales de un río brasileño, mediante tratamientos, a escala de laboratorio, como: las técnicas de membrana de nanofiltración, de ultrafiltración, el tratamiento convencional (coagulación, floculación, sedimentación y filtración en arena) y el carbón activo en polvo y en grano, como adsorbentes, buscando contribuir con conocimientos para la mejoría de la calidad del agua potable y consecuentemente a la mejoría de la calidad de vida / Many human activities contribute to environmental degradation due to the wide variety of chemical waste dumped. Some of the chemicals are quite persistent and cause serious effects on animal and human health over a long period of time, even when present in very low concentrations (Kuramitz et al, 2002), like endocrine disruptors (EDs). An endocrine disruptor (ED) as defined by the Commission of the European Communities, is an exogenous substance or mixture that alters the function(s) of the endocrine system and consequently causes adverse health effects in a person or their progeny or part of the population (CEC, 1999). As adverse health effects, medical studies have shown in recent years a decline in human reproductive capacity in most industrialized countries; an increase in the incidence of abnormalities in the development of the genitals; the appearance of menstruation increasingly earlier (early menarche); increased frequency of endometriosis; and cancers in organs that depend on hormones, such as breast, prostate, testicle and ovary. By the way, ovarian cancer is a major cause of death in the Western world (Aranda, 2004). Due to estrogenic activity both detergents and steroids have been included in the preliminary lists of various ED compounds. Nonylphenol (NP)(synthetic compound that has estrogenic activity, acts as a ED and is widely used as raw material for manufacturing detergents, plastic anti-oxidants, pesticides and as an additional agent and stabilizer of polyvinyl chloride (PVC) (Kuramitz et al, 2002)) has been classified as priority hazardous substance in the field of water policy by the European Community Water Framework Directive 2000/60/EC and by the final decision of the European Union N. 2455/2001/EC. Directive 2008/105/EC provides that NP shall be limited, as an annual average, to the maximum concentration of 0.3 μg/L and to a maximum allowable concentration of 2.0 μg/L, both for inland surface and other surface waters. The Environmental Protection Agency (EPA, 2006) provides, regarding water quality criterion, the NP concentration limits in fresh water: 28 μg/L (short term) and 6.6 μg/L (average of four days) to protect aquatic life from adverse effects. Estrone (E1) (natural estrogen, excreted by men and women in urine and feces, is present in many waters and domestic wastewater, has high environmental persistence and high potential as ED (Schäfer and Waite, 2002)) is include in EPA Contaminant Candidate List 3 (CCL 3) (2001), but there are no regulations that limit concentration of this pollutant in the water. What exists is an indication that E1 concentrations in the range between 0.01 and 0.10 μg/L exert estrogenic effects in fish (Routledge et al., 1998, Petrovic et al., 2004). Since the issue of water pollution by EDs is a very serious emerging problem, for the disturbance it causes in the human hormonal system, the objective of this study is to compare the efficiency of the elimination of NP and E1 from surface waters of a river in Brazil by treatments in laboratory scale, such as the techniques of nanofiltration and ultrafiltration membrane, conventional treatment (coagulation, flocculation, sedimentation and sand filtration) and activated carbon powder and grain as adsorbents, seeking to contribute with knowledge to improve drinking water quality and consequently quality of life.
235

Application of Speciated Isotopes Dilution Mass Spectronmetry to the Assessment of Human Health and Toxic Exposure

Fahrenholz, Timothy 19 February 2012 (has links)
Previous work by our research group demonstrated that quantitative chemical analysis of analytes, such as mercury and chromium species, in environmental matrices could be successfully carried out without using calibration curves and with correction for species interconversion by using EPA Method 6800A. This method encompasses isotope dilution mass spectrometry (IDMS) and speciated isotope dilution mass spectrometry (SIDMS), both of which are described in detail in chapter 1. Research described in this dissertation expands upon our earlier work by applying the method to the speciation of mercury in biological matrices, the speciation of glutathione in red blood cells and whole blood, and the analysis of enzyme activity in mammalian tissue. / Bayer School of Natural and Environmental Sciences; / Chemistry and Biochemistry; / PhD; / Dissertation;
236

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).
237

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.
238

Millisecond H/D Exchange Combined with Electrospray Ionization Mass Spectrometry to Study Protein¡¦s Structure

Lin, Hsuan-Chung 03 August 2004 (has links)
none
239

Towards Whole Cell Immunoproteome And Subproteomes Of Bordetella Pertussis

Tefon, Burcu Emine 01 February 2012 (has links) (PDF)
Bordetella pertussis is a gram-negative, human pathogen and etiologic agent of whooping cough (pertussis), a highly contagious, acute respiratory illness. In this study, the analysis of whole immunproteome and subproteomes of this microorganism was performed. The soluble cytoplasmic proteomes of B. pertussis Tohama I strain and a local isolate Saadet were separated by 2DE. By Western blot analysis, we identified 25 immunogenic proteins of three categories. In the first group, there were well-known proteins of the pathogen The second group comprised proteins which were already shown antigenic in certain pathogenic bacteria, but not in B. pertussis before. The third group of proteins were those which have not been shown to be immunogenic in any pathogen till the present study such as putative chromosome partition protein, preprotein translocase SecA subunit, carbamoyl-phosphate synthase large chain, PRP synthase, putative substrate-CoA ligase, lysyl-tRNA synthetase, fumaryl acetoacetase, putative peptidyl-prolyl cis-trans isomerase, aspartate-semialdehyde dehydrogenase, putative DNA-binding protein and a putative outer membrane protein. In our surfaceome study, surface proteins of two strains were identified by 2DE followed by MALDI-TOF-MS/MS analysis and also geLC-MS/MS. With these techniques 45 proteins were identified by 2DE and 226 proteins by geLC-MS/MS. The immunogenicity of surface proteins on 2DE gels were analyzed by Western blotting and among 11 identified immunogenic proteins glutamine-binding periplasmic protein, leu/ile/val-binding protein, one putative exported protein, and iron-superoxide dismutase were found to be immunogenic for the first time in Bordetella. It was also found that 16 proteins were differentially expressed in B. pertussis Saadet and Tohama I. Five proteins were expressed only in Saadet (adhesin, chaperone protein DnaJ, fimbrial protein FimX, putative secreted protein Bsp22 and putative universal stress protein), and two (ABC transporter substrate-binding protein and a putative binding protein-dependent transport periplasmic protein) only in Tohama I. In the secretome study, we identified 40 proteins by 2DE and 357 proteins by geLC-MS/MS. It was found that 12 proteins were immunogenic by Western blot analysis and the immunogenicity of putative secreted protein (BP1047) was shown for the first time in this study. In our study, PT subunit 2 and putative outer protein D (BopD) were more abundant in Saadet while one protein, glutamate synthase subunit beta was expressed at a higher level in Tohama I. Four proteins were expressed only in Saadet (two capsular polysaccharide biosynthesis protein, protein FimX and putative outer membrane permeability protein). The present study comprehensively covered almost the entire proteome of a crucial pathogen, demonstrated many novel antigens and identified hundreds of membrane-bound proteins, cell surface-associated and extracellular proteins. Thus, it is anticipated to greatly aid in a better understanding of pathogen-host relations, rational design of novel drugs and developing new generation vaccines against B. pertussis.
240

Determination of the triarylmethanes and corresponding metabolites in aquatic animal tissues by high-performance liquid chromatography-tandem mass spectrometry

Wang, Ter-min 01 September 2008 (has links)
There are two purposes in this research, one is the development of the new method which can be used for detection and quantification of triarylmethanes in fish tissues. The other is that we confirmed validation and utility of triarylmethanes by the method that is according to Commission Decision 2002/657/EC. Homogenized fish tissues were extracted twice with acetonitrile and defatted with n-hexane. HPLC separation was conducted with the RP-18 column. The mobile phases consisted of 0.5 mM ammonium acetate buffer (pH 3.8, adjusted with acetic acid)¡V ACN (contained 0.1% formic acid) solution. Triarylmethane was determined by LC-ESI-MS/MS in positive mode. The correlation coefficients of calibration curves with triarylmethane in fish tissues were 0.998 ~ 0.999. The decision limits (CC£\) were 0.16 ¡Ó 0.07 £gg/kg(MG), 0.15 ¡Ó 0.04 £gg/kg(LMG), 0.20 ¡Ó 0.13 £gg/kg(CV) and 0.23 ¡Ó 0.12 £gg/kg(LCV), and detection capabilities (CC£]) were 0.20 ¡Ó 0.09 £gg/kg(MG), 0.18 ¡Ó 0.05 £gg/kg(LMG), 0.24 ¡Ó 0.16 £ggkg-1(CV) and 0.29 ¡Ó 0.15 £gg/kg(LCV).

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