Thèse (M.Sc.)--Université Laval, 2002. / Bibliogr.: f. 175-184. Publié aussi en version électronique.

Thesis (M.S.)--Brigham Young University. Dept. of Physics and Astronomy, 2006. / Includes bibliographical references (p. 61-64).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xix, 189 p. ; also includes graphics. Includes bibliographical references (p. 175-189). Available online via OhioLINK's ETD Center.

Thesis (M.P.H.)--University of Wisconsin--La Crosse, 2002. / Includes bibliographical references (leaves 50-52).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 161-174).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 169-186).

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 147-169). Also available on the World Wide Web.

Philosophiae Doctor - PhD / Nowadays, the pollution of surface waters with chemical contaminants is one of the most crucial environmental problems. These chemical contaminants enter rivers and streams resulting in tremendous amount of destruction, so the detection and monitoring of these chemical contaminants results in an ever-increasing demand. This thesis describes the search for a suitable method for the determination of platinum group metals (PGMs) in environmental samples due to the toxicity of mercury films and the limitations with methods other than electroanalytical methods. This study focuses on the development of a novel bismuth-silver bimetallic nanosensor for the determination of PGMs in roadside dust and soil samples. Firstly, individual silver, bismuth and novel bismuth-silver bimetallic nanoparticles were chemically synthesised. The synthesised nanoparticles was compared and characterised by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), ultraviolet-visible spectroscopy (UV-Vis), Fourier-transformed infrared spectroscopy (FT-IR), Raman spectroscopy, and transmission electron microscopy (TEM) analysis to interrogate the electrochemical, optical, structural, and morphological properties of the nanomaterials. The individual silver, bismuth, and bismuth-silver bimetallic nanoparticles in the high resolution transmission electron microscopy results exhibited an average particle size of 10-30 nm. The electrochemical results obtained have shown that the bismuth-silver bimetallic nanoparticles exhibit good electro-catalytic activity that can be harnessed for sensor construction and related applications. The ultraviolet-visible spectroscopy, Fourier-transformed infrared spectroscopy, and Raman spectroscopy results confirmed the structural properties of the novel bismuth-silver bimetallic nanoparticles. In addition the transmission electron microscopy and selected area electron diffraction morphological characterisation confirmed the nanoscale nature of the bismuth-silver bimetallic nanoparticles. Secondly, a sensitive adsorptive stripping voltammetric procedure for palladium, platinum and rhodium determination was developed in the presence of dimethylglyoxime (DMG) as the chelating agent at a glassy carbon electrode coated with a bismuth-silver bimetallic nanofilm. The nanosensor further allowed the adsorptive stripping voltammetric detection of PGMs without oxygen removal in solution. In this study the factors that influence the stripping performance such as composition of supporting electrolyte, DMG concentration, deposition potential and time studies, and pH have been investigated and optimised. The bismuth-silver bimetallic nanosensor was used as the working electrode with 0.2 M acetate buffer (pH = 4.7) solution as the supporting electrolyte. The differential pulse adsorptive stripping peak current signal was linear from 0.2 to 1.0 ng/L range (60 s deposition), with limit of detections for Pd (0.19 ng/L), Pt (0.20 ng/L), Rh (0.22 ng/L), respectively. Good precision for the sensor application was also obtained with a reproducibility of 4.61% for Pd(II), 5.16% for Pt(II) and 5.27% for Rh(III), for three measurements. Investigations of the possible interferences from co-existing ions with PGMs were also done in this study. The results obtained for the study of interferences have shown that Ni(II) and Co(II) interfere with Pd(II), Pt(II) and Rh(III) at high concentrations. The interference studies of Cd(II), Pb(II), Cu(II) and Fe(III) showed that these metal ions only interfere with Pd(II) and Pt(II) at high concentrations, with no interferences observed for Rh(III). Phosphate and sulphate only interfere at high concentrations with Pt(II) and Rh(III) in the presence of DMG with 0.2 M acetate buffer (pH = 4.7) solution as the supporting electrolyte. Based on the experimental results, this bismuth-silver bimetallic nanosensor can be considered as an alternative to common mercury electrodes, carbon paste and bismuth film electrodes for electrochemical detection of PGMs in environmental samples. Thirdly, this study dealt with the development of a bismuth-silver bimetallic nanosensor for differential pulse adsorptive stripping voltammetry (DPAdSV) of PGMs in environmental samples. The nanosensor was fabricated by drop coating a thin bismuth-silver bimetallic film onto the active area of the SPCEs. Optimisation parameters such as pH, DMG concentration, deposition potential and deposition time, stability test and interferences were also studied. In 0.2 M acetate buffer (pH = 4.7) solution and DMG as the chelating agent, the reduction signal for PGMs ranged from 0.2 to 1.0 ng/L. The detection limit for Pd(II), Pt(II) and Rh(III) was found to be 0.07 ng/L, 0.06 ng/L and 0.2 ng/L, respectively. Good precision for the sensor application was also obtained with a reproducibility of 7.58% for Pd(II), 6.31% for Pt(II) and 5.37% for Rh(III), for three measurements. In the study of possible interferences, the results have shown that Ni(II), Co(II), Fe(III), Na+, SO42- and PO43- does not interfere with Pd(II) in the presence of DMG with sodium acetate buffer as the supporting electrolyte solution. These possible interference ions only interfere with Pt(II) and Rh(III) in the presence of DMG with 0.2 M acetate buffer (pH = 4.7) as the supporting electrolyte solution.

Orientador: Raimundo Souza Lopes / Coorientador: Adivaldo Henrique da Fonseca / Banca: Regina Kiomi Takahira / Banca: Pedro Paulo Pires / Resumo: A borreliose aviária é uma doença septicêmica aguda, causada pela espiroqueta Borrelia anserina, atualmente apresenta baixa incidência, porém devido ao crescimento das criações orgânicas e rústicas, maior preocupação com o bem estar animal e a diminuição do uso de antibióticos em rações, existe a preocupação com o surgimento de surtos da doença, que poderão causar prejuízos econômicos. Desta maneira, torna-se de fundamental importância a busca por terapias alternativas, entre elas, a terapia fotodinâmica, como a associação da luz ultravioleta (UV) e riboflavina, com o objetivo de controlar a enfermidade. Este estudo objetivou verificar a eficácia do tratamento com luz UV e riboflavina para inativar ou eliminar a B. anserina no soro de galinhas poedeiras, por meio de exames diagnósticos e laboratoriais, e verificar a resposta imunológica do hospedeiro. O experimento foi conduzido em duas etapas, a etapa in vivo foi formada por 42 galinhas, divididas em sete grupos, composto por seis aves: Grupo 1 (saúde); Grupo 2 (doença) inoculadas com soro parasitado por B. anserina; Grupo 3 (imunossupressor) que receberam metilprednisolona; Grupo 4 ( luz UV) que receberam soro parasitado tratado com luz UV; Grupo 5 (riboflavina) que receberam soro parasitado tratado com riboflavina; Grupo 6 (grupo veículo) que receberam soro parasitado tratado com cloreto de sódio 0,9%; Grupo 7 (tratado) que receberam soro positivo para B. anserina tratado com luz ultravioleta associada à riboflavina. A etapa in vitro, foi realizada com placas de cultivo celular, divididas igualmente à etapa in vivo. Foi possível observar que o tratamento não apresentou resultado esperado na inativação ou completa eliminação do agente. No entanto, uma ave do grupo tratado sobreviveu e apresentou recuperação clínica e laboratorial, apresentando espiroquetemia no Momento 11 e qPCR positivo no momento... / Abstract: Avian borreliosis is an acute septicemic disease caused by the spirochete Borrelia anserina, has a low incidence, however due to the growth of organic and rustic creations, greater concern for animal welfare and reducing the use of antibiotics in feed, there is concern about the emergence of disease outbreaks, which may cause economic losses. Thus, it becomes fundamental to search for alternative therapies, including, photodynamic therapy, such as the combination of ultraviolet (UV) light and riboflavin with the aim of controlling the disease. This study aimed to investigate the efficacy of treatment with riboflavin and UV light to inactivate or eliminate B. anserina from serum laying hens by diagnostic and laboratory tests and to check to the host immune response. The experiment was conducted in two stages. The first one was the in vivo step composed of 42 chickens, divided into seven groups of six birds: Group 1 (health); Group 2 (disease) inoculated with the serum parasitized by Borrelia anserina; Group 3 (immunosuppressant) receiving methylprednisolone; Group 4 (UV light) which received parasitized saline treated with UV light; Group 5 (riboflavin) which received parasitized serum treated with riboflavin; Group 6 (solvent group) parasitized receiving saline treated with 0.9% sodium chloride; Group 7 (treated) which received positive serum for B. anserina treated with ultraviolet light associated with riboflavin. The secund one was the in vitro stage performed with cell culture plates, equally divided in vivo step. It was observed that the treatment did not show expected results in the inactivation or complete elimination of the agent. However, one bird from the treated group survived and showed clinical and laboratory recovery, presenting spirochetemia at the time 11 and qPCR positive at the time... / Mestre

abstract: Advanced oxidation processes (AOP’s) are water/wastewater treatment processes simultaneously providing disinfection and potential oxidation of contaminants that may cause long-term adverse health effects in humans. One AOP involves injecting peracetic acid (PAA) upstream of an ultraviolet (UV) irradiation reactor. Two studies were conducted, one in pilot-scale field conditions and another under laboratory conditions. A pilot-scale NeoTech UV reactor (rated for 375 GPM) was used in the pilot study, where a smaller version of this unit was used in the laboratory study (20 to 35 GPM). The pilot study analyzed coliform disinfection and also monitored water quality parameters including UV transmittance (UVT), pH and chlorine residual. Pilot study UV experiments indicate the unit is effectively treating flow streams (>6 logs total coliforms) twice the 95% UVT unit capacity (750 GPM or 17 mJ/cm2 UV Dose). The results were inconclusive on PAA/UV inactivation due to high data variability and field operation conditions creating low inlet concentrations.Escherichia coli (E. coli) bacteria and the enterobacteria phage P22—a surrogate for enteric viruses—were analyzed. UV inactivated >7.9 and 4 logs of E. coli and P22 respectively at a 16.8 mJ/cm2 UV dose in test water containing a significant organics concentration. When PAA doses of 0.25 and 0.5 mg/L were injected upstream of UV at approximately the same UV Dose, the average E.coli log inactivation increased to >8.9 and >9 logs respectively, but P22 inactivation decreased to 2.9 and 3.0 logs, respectively. A bench-scale study with PAA was also conducted for 5, 10 and 30 minutes of contact time, where 0.25 and 0.5 mg/L had <1 log inactivation of E. coli and P22 after 30 minutes of contact time. In addition, degradation of the chemical N-Nitrosodimethylamine (NDMA) in tap water was analyzed, where UV degraded NDMA by 48 to 97% for 4 and 0.5 GPM flowrates, respectively. Adding 0.5 mg/L PAA upstream of UV did not significantly improve NDMA degradation. The results under laboratory conditions indicate that PAA/UV have synergy in the inactivation of bacteria, but decrease virus inactivation. In addition, the pilot study demonstrates the applicability of the technology for full scale operation. / Dissertation/Thesis / Masters Thesis Civil and Environmental Engineering 2017