This thesis presents solid phase extraction (SPE) methodologies based on mixed-mode polymeric sorbents; a mixed mode strong anion exchanger (Agilent SampliQ SAX) and a mixed mode strong cation exchanger (Agilent SampliQ SCX). Furthermore, dispersive-SPE based on a quick, easy, cheap, effective, rugged and safe (QuEChERS) method was assessed for applicability in the determination of drug residues. The mixed-mode polymeric sorbents were evaluated for the simultaneous fractionation of drugs that exhibit diverse polarities with acidic, basic and neutral functionalities in biological matrices (plasma and urine). The polymeric skeleton of these sorbents entails an exchanger group and therefore provides two retention mechanisms, strong cation or anion exchange retention mechanisms with hydrophobic interactions. It was demonstrated that with a sequential elution protocol for sample clean-up analytes were fractionated into acidic, basic and neutral classes. The SAX was employed for analysis of ketoprofen, naproxen (acidic drugs), nortriptyline (basic) and secobarbital (neutral) from urine sample. The SCX was used for fractionating phenobarbital, p-toluamide (acidic), amphetamine, m-toluidine (basic) and acetaminophen (neutral drug) from plasma sample. QuEChERS method was employed for quantitative determination of 16 polycyclic aromatic hydrocarbons (PAHs) from fish fillets and soil; 9 sulfonamides (SAs) from chicken muscles and acrylamide (AA) in cooking oil. The analyte recoveries ranged from 79.6 - 109% with RSDs ranging from 0.06 - 1.9% at three different fortification levels. Good linearity (r2 > 0.9990) was attained for most analytes. The limits of detection and quantification ranged from 0.03 - 0.84 μg/ml and 0.81 - 1.89 μg/ml respectively for analytes in biological samples. LODs and LOQs for analytes in food and environmental samples ranged from 0.02 to 0.39 and 0.25 to 1.30 ng/g respectively.

Contamination of meat with microorganisms during slaughter is inevitable. Hygiene management systems (HMSs) such as the Hygiene Assessment System (HAS) and Hazard Analysis Critical Control Point (HACCP) are used to prevent the contamination of beef with both spoilage and pathogenic microorganisms during slaughter. This study compared the effect of the HAS alone and a combination of HAS + HACCP on the microbiological quality of beef and investigated the survival of Escherichia coli O157:H7 co-cultured with different levels of Pseudomonas fluorescens and Lactobacillus plantarum on fresh beef. HAS alone and HAS combined with HACCP systems were each represented by two abattoirs. Sponge swab samples were collected from chilled beef carcasses for indicator organisms: Aerobic Plate Counts (APC), Enterobacteriaceae, Pseudomonas spp., and lactic acid bacteria. Swabs were also collected for pathogenic bacteria: E. coli O157:H7, Staphylococcus aureus and Salmonella spp. There was no significant difference between the microbiological quality of beef carcasses processed in the abattoirs with the HAS and that of beef carcasses processed in abattoirs with combined HAS + HACCP. E. coli O157:H7 was isolated from carcasses processed in an abattoir with the combined HAS + HACCP system. Moreover, although overall S. aureus counts at all abattoirs were comparable, a higher incidence (47% of carcasses) was obtained from an abattoir with combined HAS + HACCP. Salmonella spp. was not detected during the study. The microbiological quality of beef at HAS abattoirs is not significantly different to that of beef processed at HAS + HACCP abattoirs. The combined HAS + HACCP did not prevent contamination of beef carcasses with E. coli O157:H7 and S. aureus. Effective implementation of HAS can reduce contamination of beef with spoilage and pathogenic microorganisms. The effect of different levels of P. fluorescens (102 and 106 log10 cfu/ml) and L. plantarum (102 and 104 log10 cfu/ml) on the survival of E. coli O157:H7 on beef loins was investigated. Sterile beef loins inoculated with E. coli O157:H7 and P. fluorescens were aerobically stored for 7 days at 4°C, while those inoculated with E. coli O157:H7 and L. plantarum were vacuum-packaged and stored for 8 weeks at 4°C. APC, E. coli O157:H7 and either P. fluorescens or L. plantarum counts were determined at different storage intervals. For the aerobically packaged beef loins, E. coli O157:H7 was detected throughout the 7-day storage period regardless of the P. fluorescens level in the inoculum. For the vacuum packaged beef loins, similar inoculum levels of E. coli O157:H7 and L. plantarum allowed E. coli O157:H7 to survive until week 5 of storage, while a higher inoculum level of L. plantarum inhibited E. coli O157:H7 from week 3. Once fresh beef has been contaminated with E. coli O157:H7 the level of P. fluorescens in the background flora does not inhibit its survival and growth. However, under vacuum storage, the application of L. plantarum as a biopreservative inhibits the survival of E. coli O157:H7 on beef. Comprehensive strengthening of preventive strategies is required to eliminate contamination of beef carcasses with E. coli O157:H7. Bacterial contamination of carcasses during slaughter is inevitable. Effective implementation of HAS at abattoirs produces beef carcasses of microbiological quality comparable to that produced through the use of combined HAS and HACCP. While the level of P. fluorescens on beef does not inhibit the survival of E. coli O157:H7 on aerobically stored beef, the combination of L. plantarum, and low storage temperature inhibits the survival of this pathogen on beef under vacuum storage. / Thesis (PhD)--University of Pretoria, 2011. / Food Science / unrestricted

The objective of this research is to evaluate the influence of the factors identified by the Johnson, Kendall and Robert’s theory that affect the strength of the detachment force necessary to remove a particle of contaminant from a surface, and the roughness of the surface in which the contaminant is present, on predicting the efficiency of removal of loose contamination. Two methods were used to reach this objective: the first method consisted of quantifying the contamination by weight and the second method of quantifying the contamination by counting alpha and gamma particles. As a result, it was determined that for particles of 5 μm, the interaction between contaminant-wipe and contaminant-surface were significant. However, for particles between 37-149 μm, the contaminant-surface interaction was the only significant interaction affecting the amount of contamination removed. The results obtained were already used at a contaminated site, confirming the prediction of contamination removed

Current US government risk assessment and management regulations and policies are based on a position that views risk as an objective measure of a predictable physiological morbidity or mortality outcome that is not otherwise connected to social or cultural beliefs and values. Whereas human health risk assessments are meant to determine the probability of adverse impacts from particular hazards, the conventional risk assessment framework fails to consider Native American definitions of health and so risk. This study was conducted with the Coast Salish Swinomish Indian Tribal Community of Washington State, where contamination of their aquatic natural resources has been found. By conducting two series of interviews with traditional high-use seafood consumers, experts and elders from the Swinomish Indian Tribal Community, and by averting use of what I describe herein as ‘conventional’ fish consumption survey, the study allowed interviewees to provide a more complex narrative set of details and information that bestowed a much more accurate picture of the reasoning behind seafood consumption habits within the community. Among the more salient points that emerged from the interviews was that seafood represents a symbolic, deeply meaningful food source that is linked to a multi-dimensional ‘Swinomish’ concept of health. Yet drastic changes in access, harvest and consumption have occurred over time, and continue to this day. A health evaluation tool was also devised using simple descriptive scaled rankings to elucidate non-physiological health risks and impacts in relation to contaminated seafood. Findings demonstrate that community cohesion, food security, ceremonial use and knowledge transmission all play primary roles as concerns the Swinomish notions of health, and that these indicators are regarded as equally important when juxtaposed to physical indicators of health. Thus, to eat less seafood—as prescribed by current policy and decision-making procedures when contamination is present—is actually detrimental to the multi-dimensional concept of health as defined by the Swinomish. The evaluation tool may be used in conjunction with the conventional risk assessment framework to more accurately and comprehensively deduce risks and impacts. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

VANETs are the essential component of the intelligent transport system, which attract research and industrial interests increasingly. As the multifunctional mobile nodes integrating transporting, sensing, information processing, and wireless communication capabilities, vehicular nodes are facing remarkable security issues and more vulnerable to malware attack than conventional communication nodes. In this thesis, the behavior and the security issues of the worm spreading on VANETs are studied. The approaches of the worm spreading on VANETs are discussed and an infrastructure based worm containment strategy is proposed. The infrastructure based worm containment problem is modeled as minimum contamination problem by introducing the expected contamination degree. Then the existing greedy method is applied to solve the proposed problem in VANETs scenario. After that, the Grid-shrinking Greedy Method and the Simplified Greedy Method are proposed which incorporate the characteristics of road networks and VANETs respectively. Simulation results show the two proposed methods outperform the existing greedy method and the comparison method from both complexity and solution quality aspects.

Des contaminations par Enterobacter gergoviae, dans les formulations cosmétiques diverses soulèvent le problème de la résistance bactérienne aux biocides. J'ai pu mettre en évidence, que certains épisodes de contaminations apparus au sein de l'entreprise partenaire, étaient dus à un même isolat persistant suite à un système de conservation/désinfection inefficace. Aux concentrations maximales autorisées par la commission européenne, les conservateurs ont des effets bactériostatiques mais ne présentent pas d'effets synergiques en association. Par conséquent, l'adaptation aux produits cosmétiques est favorisée. Divers mécanismes de résistance peuvent être mis en place par E. gergoviae : enzymatique (synthèse de peroxyredoxine), modifications de l'enveloppe (expression d'appendices externes : flagelles ou fimbriae/pili), modification de la mobilité, et formation de biofilms. L'apparition de ces mécanismes a aussi favorisé les résistances croisées conservateurs /désinfectants-détergents. / Contaminations by Enterobacter gergoviae in various cosmetic formulations raise the problem of bacterial resistance to biocides of the species, which represent the third source of cosmetics bacterial contaminations. The collaborative cosmetic company was concerned by unrelated contaminations but some contamination events were due to persistence of isolates in internal system process, despite disinfection protocols and use of preservatives. At the maximum levels allowed by the European Commission, preservatives tested have bacteriostatic effects and do not exhibit synergistic effects in combination. Therefore, adaptation in cosmetics is facilitated. Various resistance mechanisms can be implemented by E. gergoviae: Enzymatic (peroxyredoxin synthesis), changes in the envelope (expression of external appendages: flagella or fimbriae/pili), changes in mobility and biofilm formation. The appearance of such mechanisms has also promoted a cross-resistance conservative / disinfectant - detergent.

Overhead conductors used in the transmission of power in grids around the world are generally subjected to ageing, which is the time-based change of their properties. Important properties such as corona discharge, audible noise, hydrophobicity and corrosion are usually considered and investigated. On some conductors such as the aluminium conductor steel reinforced (ACSR), a reduction in audible noise over exposure time to the service environment has been noted to occur. However, the converse has been observed for the gap-type thermal resistant aluminium conductor steel reinforced (GTACSR or “Matthew” conductor), although this conductor is preferred due to its high ampacity. The relationship between conductor hydrophobicity, audible noise, surface contamination and roughness, wettability and corrosion were investigated using All Aluminium Alloy Conductor (AAAC), Aluminium Conductor Composite Core (ACCC) and GTACSR samples. Findings from Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectric Spectroscopy (XPS) and contact angle measurements revealed that carbon, hydrocarbon and silicone contamination was responsible for the hydrophobic nature of the surface. Furthermore, electrochemical investigations and electron microscopy showed that pitting or/and crevice corrosion were the predominant corrosion mechanisms on these conductors. Exposure to simulated industrial and marine environments further confirmed this finding and also showed that general corrosion also occurs on relatively uncontaminated conductors, thereby changing their surface roughness, as seen from the White Light Interferometry results. Corrosion was observed to be accelerated by the presence of surface contaminants such as oils and carbon, as these facilitated water (droplet) retention by reducing the conductor’s surface energy. Reduction/elimination of surface contamination/hydrophobicity were the desired solutions to the problem, and this was achieved by grit blasting. Partial/complete oxidation of the silicones resulted in the reduction/elimination of sample hydrophobicity – this was seen from more contact angles measurements and XPS data. Grit blasting also restored conductor cleanliness and roughened the surface sufficiently to produce surface run-off.

Two hybridoma clones, labelled 4D10 C1 and 2H4 H12, produced monoclonal antibodies which recognized the outer membrane of an enteropathogenic Escherichia coli (EPEC) 0142:K86:H6 in an enzyme-linked immunosorbent assay (ELISA) and the whole cell in an immunofluorescence assay. Large scale production of the monoclonal antibodies was accomplished through ascites production in balb/c mice. Purification of the ascites fluid was achieved by gel filtration and ion exchange chromatography. Isotyping of the purified fractions showed 4D10 C1 to be an IgG2 and 2H4 H12 an IgM. These monoclonal antibodies were screened by immunofluorescence assay against several pathogenic and nonpathogenic strains of E.coli in addition to other Enterobacteriaciae. Results of the screening showed these antibodies to be specific for the E.coli serotype to which they were raised. Minimal cross-reactivity with other Enterobacteriaceae was observed. In a separate and concurrent project, the use of an ELISA capable of detecting ß-N-acetylglucosaminidase (NAGase) was examined. White Leghorn hens were injected with commercially prepared bovine NAGase. Eggs were collected and the immunoglobulin fraction separated from the egg yolk by polyethylene glycol precipitation followed by ion exchange on a DEAE-Sephacel column. The use of the purified immunoglobulins was examined in a sandwich, double-sandwich and a competitive ELISA. A statistically significant standard curve for the detection of NAGase was successfully derived using a double-sandwich ELISA when rabbit immunoglobulin was used to coat the microwell plates. This assay was used to measure the NAGase concentration in press juice and fish extract of fresh and frozen salmon muscle samples. The ratio of the NAGase concentration in the press juice to the total NAGase concentration was compared. No significant difference was found between the calculated concentration ratios of the fresh muscle samples and samples frozen for 1 week at -20°C. / Land and Food Systems, Faculty of / Graduate

Teores anômalos de cromo hexavalente vêm sendo detectados na água subterrânea de vários municípios da região noroeste do Estado de São Paulo, sendo que em Urânia foram observadas as maiores concentrações do elemento, afetando as condições do consumo e uso humano. Estudos prévios realizados indicaram que a origem do cromo na água subterrânea é natural e proveniente de minerais com cromo no aqüífero profundo. Este projeto teve como principais objetivos: (1) a caracterização química e mineralógica da fase sólida do aqüífero profundo, realizada em testemunhos de duas sondagens profundas; (2) a caracterização da estratificação das concentrações de cromo na água subterrânea, com base na coleta e análise de amostras de água provenientes de poços de monitoramento instalados em diferentes profundidades do aqüífero; (3) a identificação dos processos hidrogeoquímicos que justificam a passagem do cromo da fase sólida para a água. Para tanto, foram realizadas análises químicas e mineralógicas por WDS, microssonda eletrônica e CTC, diversos métodos de análise química da água subterrânea, utilizados programas como o AquaChem e PHREEQc para trabalhamento do banco de dados e modelagens, além de uma grande variedade de experimentos de laboratório. As análises químicas por WDS e microssonda eletrônica indicaram concentrações de cromo de até 12.600 ppm em cristais de diopsídio, e de 650 ppm em capas de argilomineral. O material sólido apresenta uma capacidade de troca de cátions da ordem de 30 meq/100g, com ordem de abundância dos cátions Ca>>Mg>>K>Na. Na porção profunda do aqüífero, foi observada uma anomalia de sódio adsorvido, influenciando na composição química da água. As características hidroquímicas do aqüífero indicaram a ocorrência de estratificações de águas com diferentes perfis hidroquímicos. As águas são, no geral, do tipo bicarbonatadas cálcicas, porém com uma elevação do conteúdo de sódio na base do aqüífero. O cromo foi identificado na água predominantemente na forma hexavalente, com concentrações que atingiram 0,139 mg/L, acima, portanto do limite de potabilidade (0,05 mg/L). A ocorrência de valores mais elevados de cromo na água parece estar associada a ambientes de elevados pH e Eh, como observado no aqüífero profundo, enquanto que nas zonas rasas, que apresentam valores de pH e Eh neutros, apresentaram baixo conteúdo de cromo. Os principais resultados dos ensaios de laboratório indicaram que há passagem de cromo para água subterrânea, através do ataque aos minerais pesados com pH ácido; os ensaios de batch test realizados apontaram que o material sólido do aqüífero apresenta alguma capacidade de adsorção de Cr6+, chegando a um máximo de 0,12 ppm; o experimento de solubilização indicou a passagem de pequenas concentrações de cromo para a água e que a composição química da água do ensaio é semelhante à água do aqüífero. O modelo mais provável das reações geoquímicas que explicam a passagem do cromo da fase sólida para a água é apresentado a seguir, divido por etapas: (1) o intemperismo dos diopsídios cromíferos deve ser o processo inicial de disponibilização de cromo para a água, resultando na precipitação do cromo como hidróxidos ou sendo adsorvido por hidróxidos de ferro e manganês; (2) ocorrência de uma reação de oxi-redução a partir do cromo trivalente que ocorre nos minerais secundários, disponibilizando o cromo para a água subterrânea, sendo que esta oxidação ocorre a partir da redução de óxidos de manganês presentes como minerais em aqüíferos, liberando Mn2+; (3) O Cr3+ é rapidamente e fortemente imobilizado por adsorção em argilominerais de baixo valor de pHpzc, enquanto que o Cr6+, devido à sua natureza aniônica, é preferencialmente retido em superfícies carregadas positivamente, como os óxidos e hidróxidos de ferro e alumínio (minerais com elevados valores de pHpzc), principalmente em condições hidroquímicas neutras a ácidas; (4) altas concentrações de OH-, de HCO3- e de CO3 2- provavelmente elevam a competição pelos sítios de adsorção de ânions e causam a dessorção dos ânions de Cr6+ para a água do aqüífero. / Anomalous hexavalent chromium contents have been detected in groundwater in many municipalities of the northwestern region of São Paulo state. In the city of Urânia, the highest concentrations of this element have been observed, affecting the conditions for human consumption. Previous studies indicated that the origin of chromium in groundwater is from natural sources and derived from chromium minerals in the deep aquifer. The main objectives of this research are to: (1) characterize chemically and mineralogically the solid phase from the deep aquifer; (2) characterize the stratification of chromium concentrations in groundwater, based on sampling and analysis of groundwater from wells installed in different depths of the aquifer; (3) identify hydrogeochemical processes that justify the passage of chromium from solid phase to groundwater. To achieve these objectives, chemical and mineralogical analysis by WDS, microprobe and CEC were made, diverse chemical analytical methods were used for groundwater, database and modeling were used through AquaChem and PHREEQc programs, besides a great variety of laboratory experiments. Chemical analysis from WDS and microprobe indicated chromium concentrations of up to 12.600 ppm in diopside crystals, and up to 650 ppm in clay mineral coats. The solid material has a Cation Exchange Capacity (CEC) of about 30 meq/100g, with cation abundance order of Ca>>Mg>>K>Na. In the aquifer deep zone, it was observed an adsorbed sodium anomaly, that influences groundwater chemical composition. The aquifer hydrochemical characteristics indicated the occurrence of water stratifications with different hydrochemical profiles. The groundwaters are, in general, calcium bicarbonated, with a elevation of sodium contents in the base of the aquifer. Chromium was identified predominatly in hexavalent state of oxidation, with concentrations of up to 0,139 mg/L, thus above potability standards (0,05 mg/L). The occurrence of higher chromium concentrations in groundwater seems to be related to high pH and Eh environments, whereas shallow zones, that have neutral values of pH and Eh, presented low chromium contents. The main results of laboratory experiments have indicated that there is passage of chromium to groundwater through acid etching in heavy minerals; batch tests have shown that solid phase has some sorption capacity, reaching a maximum of 0,12 ppm; solubilization experiment indicated the passage of low concentrations of chromium to water and that chemical composition from the experiment water is similar to groundwater. The probable model that explain the passage of chromium from solid phase to groundwater is presented hereafter, divided in steps: (1) it is indicated that weathering of chromium diopsides must be the initial process of availability of chromium to water; (2) hexavalent chromium can only occur in groundwater after the occurrence of an oxi-reduction reaction from the trivalent chromium that occurs in minerals. Many authors recognize that this oxidation occurs from the reduction of manganese oxide presented as minerals in the aquifer, releasing Mn2+, that later will be oxidated again; (3) the trivalent chromium is rapidly and strongly immobilized by sorption in clay minerals of low values of pHzpc, whereas the hexavalent chromium, due to its anionic nature, is preferably retained in positively charged surfaces, like iron and aluminium hydroxides (minerals with high values of pHzpc), mainly in neutral to acid hydrochemical conditions; (4) high OH-, HCO3 - and CO3 2- concentrations probably elevate the competition for anion sorption sites and cause the desorption of hexavalent chromium anions to groundwater.

Submitted by Adriana Martinez (amartinez@unoeste.br) on 2017-10-23T11:44:35Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Letícia.pdf: 5591928 bytes, checksum: 2cba7167a042b5176b457d4b899e2add (MD5) / Made available in DSpace on 2017-10-23T11:44:35Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Letícia.pdf: 5591928 bytes, checksum: 2cba7167a042b5176b457d4b899e2add (MD5) Previous issue date: 2017-03-10 / Cemeteries are intrinsic to society and need to be analyzed in order to provide a harmonious relationship with the environment, minimizing the impacts that this activity can generate. According to the contamination potential of the cemeteries, and the changes in the physical and biotic spheres, a potential environmental impact is attributed to cemetery activity. The liquid released by the decomposition of the corpses, the necrochorume, is the main cause of environmental pollution by the cemeteries. The present work had as objective to carry out a historical survey of the cemeteries of Presidente Prudente; to analyze the water quality of water bodies near cemeteries; as well as to analyze the biodiversity of plant species and birds. The research methodology consisted of a bibliographical survey regarding the history of cemetery activity, burial forms and environmental impacts of cemeteries. Physical-chemical and microbiological analyzes were carried out on surface water samples collected at points near the cemeteries, in addition to the survey of plant and bird species present in the cemeteries. From the results obtained through fieldwork, laboratory and literature reviews it was possible to identify that the cemeteries of the municipality of Presidente Prudente-SP can generate negative environmental impacts on the environment, causing contamination of water resources. Biodiversity is not satisfactory, so it is recommended variation of the tree species to guarantee the biodiversity of the place and potentially attract more bird species. / Os cemitérios são intrínsecos à sociedade e precisam ser analisados a fim de proporcionar uma relação harmoniosa com o meio ambiente, minimizando os impactos que essa atividade pode gerar. De acordo com a potencialidade de contaminação dos cemitérios, e as alterações nos meios físico e biótico, é atribuída à atividade cemiterial um potencial impacto ambiental. O líquido liberado pela decomposição dos cadáveres, o necrochorume, é a principal causa da poluição ambiental pelos cemitérios. O presente trabalho teve como objetivo realizar um levantamento histórico dos cemitérios de Presidente Prudente, analisar a qualidade da água de corpos hídricos próximo aos cemitérios, bem como analisar a biodiversidade de espécies vegetais e aves. A metodologia de pesquisa consistiu no levantamento bibliográfico sobre o histórico da atividade cemiterial, as formas de sepultamento e os impactos ambientais dos cemitérios. Análises físico-químicas e microbiológicas foram executadas em amostras de água superficiais, coletadas em pontos próximos dos cemitérios e o levantamento das espécies vegetais e aves presentes nos cemitérios também foram realizados. A partir dos resultados obtidos por meio de trabalhos de campo, laboratoriais e revisões de literatura foi possível identificar que os cemitérios do município de Presidente Prudente-SP podem proporcionar impactos ambientais negativos no meio ambiente, causando contaminação dos recursos hídricos. A biodiversidade não é satisfatória, por isso recomenda-se variação das espécies arbóreas para garantir a biodiversidade do local, podendo atrair dessa forma mais espécies de aves.