Perfluorinated carboxylates (PFCAs) are persistent and ubiquitous in the environment. Humans are exposed to PFCAs through direct and indirect sources, although the relative importance of each is uncertain. Direct sources of PFCAs have been attributed to two primary fluorochemical manufacturing processes: electrochemical fluorination (ECF) and telomerization. A focus of this thesis was to elucidate an additional direct source of PFCAs resulting from the direct fluorination of polyolefin materials. High density polyethylene bottles with varying levels of fluorination were observed to contain significant amounts of PFCAs, particularly those with carbon chain-lengths ≤ C6, marking an unexplored source of PFCA exposure. PFCAs are also produced indirectly from the biotransformation of fluorotelomer-based compounds, such as polyfluoroalkyl phosphate esters (PAPs) and fluorotelomer alcohols (FTOHs). During this transformation process, two predominant classes of metabolic intermediates are formed: the fluorotelomer unsaturated aldehydes (FTUALs) and the fluorotelomer unsaturated carboxylic acids (FTUCAs). Another focus of this thesis was to examine the reactivity of FTUALs and FTUCAs with endogenous nucleophiles such as glutathione (GSH), select amino acids, and model proteins. FTUALs formed adducts with all nucleophiles examined, where those having shorter carbon chain lengths (i.e. 6:2 and 8:2 FTUAL) were more reactive than longer carbon chains (i.e. 10:2 FTUAL). By contrast, FTUCAs had comparably limited reactivity; although FTUCAs showed mild reactivity with GSH, they did not react with any other nucleophiles. In vitro and in vivo experiments were carried out to determine the extent of protein binding formed from the biotransformation of fluorotelomer-based compounds, including the 8:2 FTOH and the 6:2 PAP diester. A significant portion of these biotransformations yielded covalent protein binding at nmol/mg protein concentrations. Protein adducts were observed predominantly in rat liver and also in plasma and kidney. The formation of reactive intermediates may be toxicologically important through protein deactivation. Cellular toxicity of FTUALs was significantly higher compared to PFCAs and the acid metabolic intermediates (i.e. FTUCAs). The EC50 values calculated from dose-response incubations were dependant on chain length and functional group. The work in this thesis examined an unexplored consequence of indirect exposure to PFCAs, potentially impacting the relative importance of PFCA exposure sources.

Perfluorinated carboxylates (PFCAs) are persistent and ubiquitous in the environment. Humans are exposed to PFCAs through direct and indirect sources, although the relative importance of each is uncertain. Direct sources of PFCAs have been attributed to two primary fluorochemical manufacturing processes: electrochemical fluorination (ECF) and telomerization. A focus of this thesis was to elucidate an additional direct source of PFCAs resulting from the direct fluorination of polyolefin materials. High density polyethylene bottles with varying levels of fluorination were observed to contain significant amounts of PFCAs, particularly those with carbon chain-lengths ≤ C6, marking an unexplored source of PFCA exposure. PFCAs are also produced indirectly from the biotransformation of fluorotelomer-based compounds, such as polyfluoroalkyl phosphate esters (PAPs) and fluorotelomer alcohols (FTOHs). During this transformation process, two predominant classes of metabolic intermediates are formed: the fluorotelomer unsaturated aldehydes (FTUALs) and the fluorotelomer unsaturated carboxylic acids (FTUCAs). Another focus of this thesis was to examine the reactivity of FTUALs and FTUCAs with endogenous nucleophiles such as glutathione (GSH), select amino acids, and model proteins. FTUALs formed adducts with all nucleophiles examined, where those having shorter carbon chain lengths (i.e. 6:2 and 8:2 FTUAL) were more reactive than longer carbon chains (i.e. 10:2 FTUAL). By contrast, FTUCAs had comparably limited reactivity; although FTUCAs showed mild reactivity with GSH, they did not react with any other nucleophiles. In vitro and in vivo experiments were carried out to determine the extent of protein binding formed from the biotransformation of fluorotelomer-based compounds, including the 8:2 FTOH and the 6:2 PAP diester. A significant portion of these biotransformations yielded covalent protein binding at nmol/mg protein concentrations. Protein adducts were observed predominantly in rat liver and also in plasma and kidney. The formation of reactive intermediates may be toxicologically important through protein deactivation. Cellular toxicity of FTUALs was significantly higher compared to PFCAs and the acid metabolic intermediates (i.e. FTUCAs). The EC50 values calculated from dose-response incubations were dependant on chain length and functional group. The work in this thesis examined an unexplored consequence of indirect exposure to PFCAs, potentially impacting the relative importance of PFCA exposure sources.

Purpose To investigate the impact of cigarrete smoking in a group of otherwise healthy young individuals on: 1) Retinal blood flow using Doppler based SD-OCT, 2) Retinal vascular reactivity using a gas sequencer to provoke hypercapnia via constant changes in PETCO2 (end-tidal partial pressure of CO2) and in PETO2 (end-tidal partial pressure of O2). Methods An automated gas flow controller was used to achieve normoxic hypercapnia in ten non-smokers (mean age 28.9 yrs, SD 4.58) and nine smokers (mean age 27.55 yrs, SD 4.77). Retinal blood flow measurements were obtained using Doppler OCT and cannon laser blood flowmeter (CLBF) during baseline, normoxic hypercapnia (15% increase in PETCO2 relative to homeostatic baseline) and post-hypercapnia in both the groups. Exhaled carbon monoxide level was measured in all subjects. Results In non-smokers, retinal arteriolar diameter, blood velocity and flow increased by +4.1% (SD 2.8, p<0.0001), +16.7% (SD 14.6, p=0.0004) and +29.6% (SD 12.5, p<0.0001) respectively, during normoxic hypercapnia; Similarly, the venous area, venous velocity and total retinal blood flow increased by 7% (SD 8.6, p=0.0418), 18.1% (SD 20.8, p=0.0068) and 26% (SD 22.9, p<0.0001) respectively. In smokers, normoxic hypercapnia resulted in a significant increase in velocity by 12.0% (SD 6.2, p=0.0019) and flow by 14.6% (SD 9.5, p=0.0029); though arteriolar diameter increased by 1.7% (SD 1.7, p=0.2616), the result was not statistically significant. Total retinal blood flow increased significantly by 19.3% (SD 18.4, p=0.002) in response to normoxic hypercapnia. However, there was no significant difference in venous area (p=0.3322) and venous velocity measurements (p=0.1185) during hypercapnia compared to baseline and recovery. Comparing smokers and non-smokers, only the percentage change in arteriolar diameter (p=0.0379) and flow (p=0.0101) was significantly different among the groups. Group mean PETCO2 was increased by 15.9% in the non-smoking group and by 15.7% in the smoking group, with a concomitant increase in PETO2 by approximately 1.5 to 2% in both groups. There was no significant difference in baseline PETCO2 level between smokers and non-smokers. Conclusions Retinal vascular reactivity in response to normoxic hypercapnia is significantly reduced in young healthy individuals who smoke compared to non-smokers. Further studies are needed to elucidate the exact reason behind the impaired retinal autoregulation to provocative stimuli in smokers.

Persistent organic pollutants are a well-known threat to the environment. Substances such as polycyclic aromatic hydrocarbons and chlorinated organic compounds in contaminated soil and groundwater can have severe and long-lasting effects on health in animals and humans. There is an urgent need for the development of safe technologies for their effective removal. Originally developed for mineral processing, mechanical treatment by ball milling is an extremely versatile technique for the degradation of toxic compounds. Reactive milling can rapidly destroy organic compounds without producing hazardous wastes. Complete breakdown of the organic molecules is achieved after relatively short milling times. Successful tests were conducted on polychlorobiphenyls (PCBs), DDT, DDD, DDE, Dieldrin and hexachlorobenzene with a conversion yield in the of greater than 99% (Hall et al., 1996; Monagheddu et al., 2000; Zhang et al., 2001; Zhang et al., 2002; Tanaka and Zhang, 2003; Pizzigallo et al., 2004; Nomura et al., 2005; Bellingham, 2006).In this study reactive ball milling was used to investigate the destruction of two classes of persistent organic pollutants environmental contaminants. The compounds studied are either known environmental pollutants or simple analogues. These were chosen as being representative of pollutants to investigate the pathway using ball milling destruction and in most cases were relatively small molecules so that the intermediates could be more easily identified. The first class of compounds was polycyclic aromatic compounds. Some smaller members of this class such as naphthalene, anthracene were investigated. The second class of compounds were some analogues of environmentally hazardous hydroxylated and halogenated compounds such as chloronaphthalene, bromonaphthalene, 1- naphthol, 2-naphthol and pentachlorophenol under reactive milling using GCMS analysis of the degradation pathway. Destruction efficiencies greater than 99% have been achieved for a number of organic compounds. Several different intermediates have been identified during the milling degradation. There was also some evidence from this study that halogens could be transferred between compounds during milling. The final products of the milling destruction of these compounds are an amorphous carbon residue and inorganic chloride or bromides. It was proposed that large amounts of halogens could be found however the results showed that small amounts detected. At early stages of milling a number of intermediate breakdown products were detected which were destroyed on extended milling. The core objective of this research was to clarify the reaction mechanisms pathways used of more complex polycyclic aromatic hydrocarbons and aromatic organ halogen compounds. This study is a part of a long-term research project on the destruction of toxic organic compounds by reactive milling.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: William J. Leigh. Includes bibliographical references. Also available online.

Thesis (Ph. D.)--University of Hong Kong, 1992.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

[pt] A Indústria siderúrgica, visando contribuir com a minimização das emissões de CO2, têm promovido o estudo de vários materiais carbonosos, um deles sen-do a alternativa relacionada à utilização do carvão vegetal como fonte renovável. O objetivo principal desse trabalho foi medir, em escala de laboratório, a reativi-dade ao CO2 dos materiais carbonosos, em particular o uso do carvão vegetal em comparação com o mineral, o coque metalúrgico e o coque verde de petró-leo, utilizando para tal o método de perda de peso (ASTM D5341-99). O proces-so se realizou usando briquetes de cada material, previamente cominuido a um tamanho de partícula menor que 125 m, levados a um forno tubular a uma tem-peratura de trabalho de 1100 garus Celsius, com injeção de N2 para manter uma atmosfera inerte apenas no inicio e no final dos ensaios, sob um fluxo de 0,6 Nl/min, visan-do as etapas de aquecimento e resfriamento. Utilizando como agente oxidante o CO2 durante 2h, com um fluxo de 0,9 Nl/min, todos os tipos de briquetes foram tratados na temperatura do ensaio (1100 graus Celsius). Os resultados obtidos mostraram que o carvão vegetal foi o que apresentou maior reatividade e o coque verde de petróleo a menor, entre todos os materiais ensaiados, tanto para os briquetes não desvolatilizados como desvolatilizados. Quanto ao carvão mineral e o coque, eles situaram suas reatividades intermediariamente, ficando o carvão mineral com maiores valores de reatividade do que o coque, tanto no estado desvolatilizado como no não desvolatilizado. / [en] The steel industry contributes to the minimization of emissions of CO2 promoting the study of carbonaceous materials, one of them being the charcoal, a renewable source. The main objective of this study was to measure, in a laboratory scale, selected carbonaceous materials reactivity for CO2. To perform it, charcoal was elected to be compared with coal, metallurgical coke and green petroleum coke (pet coke). The quantitative results were obtained by the method of weight loss (ASTM D5341-99). The procedure was carried out using briquettes of each material, previously grinded to a particle size smaller than 125 m, and fed to a tubular furnace at a temperature of 1100 degrees Celsius , using a N2 injection, with a stream of 0.6 Nl/min, to insure an inert atmosphere only during heating and cooling steps of the experiments. To perform the reactivity tests, CO2 was used as the species to react with the C element present at the samples composition. The tests took 2 hours, with a CO2 flow rate of 0.9 Nl/min, in a temperature of 1100 degrees Celsius. According to the results obtained, it was found that the charcoal has the higher reactivity and the green petroleum coke the less reactive. For the metallurgical coke and coal, their reactivities were intermediary between charcoal and green pet coke, being coal more reactive than coke for both, volatilized and non-volatilized samples.

Les évolutions technologiques notamment dans la télécommunication ou le transport nécessitent des systèmes de stockage de l’énergie de plus en plus performants. Dans le cas des transports, l’utilisation d’énergie fossile est encore la plus rependu. Mais la raréfaction de ces ressources, et le réchauffement climatique en partie dû au gaz CO2 rejeté par la combustion de celle-ci a mené à une prise de conscience d’un besoin de transition énergétique. Le stockage de l’énergie sous forme électrochimique (batteries) permet de s’affranchir de ces défauts. L’un des matériaux d’électrode positive les plus utilisé pour les batteries Li-ion est le LiCoO2. Il est aujourd’hui remis en question, pour des raisons de performance, mais aussi de coût et de toxicité du cobalt. Une substitution du cobalt par d’autres métaux de transition a été testée avec succès. Le matériau LiNi1/3Co1/3Mn1/3O2 (NMC) a montré des performances électrochimiques supérieures au LiCoO2. Un autre matériau d’électrode positive en commercialisation, le matériau spinelle LiMn2O4, offre des capacités intéressantes.Les performances électrochimiques de ces matériaux peuvent être améliorées. La durée de vie de ces batteries est en partie limitée par des phénomènes aux interfaces électrode/électrolyte. Il est nécessaire d’étudier ces phénomènes encore mal compris. Lors de cette étude, nous nous intéresserons à la réactivité de surface d’un matériau modèle Li2MnO3 ; et des spinelles par une approche mêlant expérience et théorie. Notre stratégie opératoire est basée sur l’adsorption de sonde gazeuse suivit d’une étude multi-échelle sur des matériaux modèles couplant expérience et théorie.Une première étude porte sur la réactivité de surface des faces (001) des cristaux de Li2MnO3 par analyse XPS et Auger de l’adsorption de sonde SO2, ainsi que de de la modélisation de ces réactions d’adsorption. Puis une seconde étude s’intéresse au rôle du degré d’oxydation du manganèse dans la réactivité de surface avec une étude sur les spinelles. La dernière partie de la thèse porte sur l’impact des fautes d’empilement sur la réactivité de surface du matériau Li2MnO3 sous forme de poudre. / LiCoO2 from layered lithium oxide family, is the most widely used Li-ion batteries positive electrode material. To support the global demand for more efficient batteries material, much research has been performed to explore alternative materials as mixed transition metal oxides LiNi1/3Mn1/3Co1/3O2 (NMC), with a larger capacity (140 mAh.g-1 for LiCoO2 vs. 180 mAh.g-1 for NMC) and a good cyclability. Its main advantages are its lower cost and toxicity, due to the lower content in Co, as well as its higher thermal stability in the delithiated state, i.e. in the charge state of the battery. The large content in Mn at the tetravalent state, which is stable in temperature, allows to stabilize the layered structure and to postpone at higher temperatures all the reactions involved during the thermal degradation of NMC, i.e. the cationic migrations, the oxygen loss and the associated reduction of the transition metal ions. A new series of layered oxide compounds Li1+xM1-xO2, called the Li-rich, was recently shown to be very attractive as delivering exceptional reversible capacities (over 250 mAh.g-1).For these overlithiated manganese-rich compounds the redox processes were shown to involve reversibly (at least in part) the transition metal and the oxygen anion. For all these layered oxides, there is a partial dissolution of the transition metals in the electrolyte, whose rate strongly depends on the cycling conditions (temperature, potential window …) and especially on the aging and storage conditions.Within this framework, a strategy combining adsorption of gaseous probe molecules (SO2) monitored by XPS and periodic DFT calculations has been developed. At an experimental level, this methodology allows the identification of the adsorption mode and the determination of the active sites concentration. This strategy has been used with LiCoO2 and NMC material, and has shown the surface reactivity of these materials. The present work uses this strategy for studying the role of surface manganese on reactivity surface. We propose to study the material LiMn2O4 and Li2MnO3, as reference materials for respectively manganese +III/+IV and manganese +IV, to see the role of surface manganese oxidation state on layered lithium oxide surface for surface reactivity. We showed that the surface reactivity depends on the crystallographic face orientation of the material, in good agreement with experimental and theoretical studies.The surface reactivity depends on the crystallographic face in the case of LiMn2O4 crystals. The calculations of adsorption on the most stable surface show different an evolution of surface reactions. These calculations have been combining with X-ray photoelectron spectroscopy study of LiMn2O4 materials.

Made available in DSpace on 2014-06-11T19:27:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-05-22Bitstream added on 2014-06-13T20:57:20Z : No. of bitstreams: 1 monteiro_ger_me_jabo.pdf: 4718837 bytes, checksum: 348326537ee49fc7b15073f8d7e90dfd (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / No presente estudo avaliou-se o desenvolvimento de resistência a ninfas do ixodídeo Amblyomma cajennense, induzida por infestações controladas, e a possível existência de reatividade cruzada com Amblyomma hebraeum. Para tal, caprinos sem contato prévio com carrapatos, com seis meses de idade, machos ou fêmeas, foram infestados três vezes sucessivamente com ninfas de A. cajennense. Ademais, outro grupo de caprinos foi infestado nas mesmas condições com ninfas de A. hebraeum e colhidos soros para pesquisa de possível reatividade cruzada com A. cajennense. Observou-se que caprinos desenvolveram resistência apenas parcial a ninfas de A. cajennense, como demonstrado pela alteração significativa dos seguintes parâmetros biológicos das ninfas, em relação à primoinfestação: redução de 41,7% e 37,1% no peso de ingurgitamento, respectivamente na 2ª e 3ª infestações; aumento de 20% no período de ecdise e redução de 25,7% na taxa de ecdise, respectivamente nas 3ª e 2ª infestações. Não houve alteração no período de ingurgitamento nem na porcentagem de recuperação de ninfas com as infestações sucessivas. A reação cutânea induzida pelas ninfas de A. cajennense durante as infestações em caprinos caracterizou-se por infiltrado de células inflamatórias, predominantemente neutrófilos e basófilos, estas últimas envolvidas na imunidade a carrapatos por meio de hipersensibilidade basofílica cutânea. Células apresentadoras de antígeno, nomeadamente macrófagos, linfócitos B e células dendríticas foram detectadas por imunoistoquímica em linfonodos drenantes de locais de fixação dos carrapatos, em maior número nos linfonodos dos animais infestados... / This study evaluated the acquision of resistance against Amblyomma cajennense nymphs in naïve goats, induced by repeated and controlled infestations, and a possible cross-reactivity with A. hebraeum. Ten naive goats, of both sexes, aged six months were used throughout the experiment. Animals were infested artificially thrice, 30 days intervals between infestations. In addition, goats were infested at same conditions with the tick A. hebraeum as well. Sera from these animals were collected looking for possible cross-reactivity between antigens from these ixodids. It was observed that goats developed partially resistance to A. cajennense nymphs from the 1st infestation on as shown by changes in some biological parameters, as follows: increase of 41.7% and 37.1% in engorgement weight, respectively at the 2nd and 3rd infestations, decrease in 25.7% in nymph s ecdise rate and increase of 20% in ecdise period, respectively at the 3rd and 2nd infestations. It was not observed alterations in engorgement period and percentage of yielded nymphs. Biopsies of tick bite lesions induced by A. cajennense nymphs during infestations in goats were characterized by inflammatory reaction with cellular influx by neutrophils and basophils predominantly, being the last one involved in the well-known cutaneous basophilia. Antigen presenting cells like macrophages, B-lymphocytes and dendritic cells were detected by immunohistochemical analysis of lymph nodes draining tick infested areas. It should be stressed that these cells were found in higher numbers at lymph nodes from infested goats than from the naïve ones. Western blotting analysis of nymphal A. cajennense extracts revealed shared polypeptides (160, 90 and 16kDa) when used sera from goats infested with A. cajennense either A. hebraeum, indicating cross reactivity between these two tick species.