Thesis (M.SC.) - Carleton University, 2007. / Includes bibliographical references. Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 255-263). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: zeolite adsorption, TBA, tert butyl alcohol, wastewater remediation. Includes bibliographical references (leaves 60-62 ).

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

Thesis (Ph. D. in Chemistry)--Vanderbilt University, Dec. 2006. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007. / Robert Dickinson, Committee Member ; Athanasios Nenes, Committee Member ; David Tan, Committee Member ; Armistead Russell, Committee Member ; Yuhang Wang, Committee Chair.

No description available.

The emergence of complex, carefully designed, molecular architectures incorporating either a lanthanide ion or the porphyrinic macrocycle have stimulated significant interest of late, particularly in the fields of molecular switches, molecular machines and data storage systems. The integration of these emissive species has been shown to permit the analysis of conformational, coordinative, or electronic change, and employed, in the case of the porphyrinic macrocycle, to acquire a deeper understanding of the natural process of photosynthesis, thus opening up the possibility of developing more efficient and inexpensive photovoltaic cells. This thesis begins by providing insight into the generation of cathodic photocurrent density within both monophasic and biphasic self-assembled monolayers, before documenting how the magnitude of such photoelectochemical output can be gated upon the integration of an electron relay moiety, both at the interface and into solution. The introduction of an electron relay moiety into solution has been shown to bring about increases of up to 283 % in the magnitude of the cathodic photocurrent density acquired, whilst optimisation of the distances between the metallic interface, the electron relay moiety and the porphyrinic macrocycle has also proven beneficial. Greatest photoelectrochemical output (5.1 x 1014 nA mol-1 cm-2) is realised when the porphyrinic macrocycle is covalently tethered at a distance of 4.6 nm from the quenching, metallic interface, and the relay moiety integrated at a distance of 1.7 nm from the interface and 2.9 nm from the porphyrinic macrocycle, respectively. However, greatest variation (94 %) in the magnitude of the cathodic photocurrent densities acquired is observed when the distance between the porphyrinic macrocycle and the gold surface is kept at 3.3 nm, and the relay moiety situated at either 1.2 nm or 1.7 nm from the interface, respectively. Research then moved towards trying to integrate this established conformational ruler within a porphyrin-appended, bistable [2]rotaxane. Its implementation served to try to ensure that photoelectrochemical differentiation of the ground state coconformation (GSCC) and the metastable state co-conformations (MSCC) was viable, thus enabling the efficient resolution of anion-induced molecular motion within a dynamic supramolecular architecture by means of a novel approach. The focus of this thesis then shifts to the assembly of novel, optically switchable, ternary complexes exhibiting charge-transfer based on the donor-acceptor interaction between an electron-rich naphthalene derivative (EuNap) and MV2+, an electron-poor, redox-addressable moiety. Prior to the deposition of (MV, EuNap)-CB[8] at the interface, the homoternary analogue ((MV+.)2-CB[8]) was acquired upon one electron reduction of (MV, EuNap)-CB[8] in the presence of excess MV2+. This process was revealed to be reversible upon the application of a stream of oxygen, and the relative concentration of each complex present in solution quantified upon mathematical manipulation of the biexponential decay curve acquired; upon the addition of sodium thiosulfate (Na2S2O3), the percentage of uncomplexed EuNap (τ = 0.60 ms cf. τ = 0.1 ms (MV, EuNap)-CB[8]) present in solution increased in accordance with the generation of ((MV+.)2-CB[8]) and loss of the charge-transfer interaction (λmax = 390, 490 nm), of which has been shown to quench lanthanide luminescence (Eu3+, Yb3+, Nd3+). Thus, the assembly of a molecular switch is documented which may be followed qualitatively at higher concentration by a visible colour change, and at low concentrations quantitatively by virtue of luminescence spectroscopy. No optical output (λex = 227 nm, λem = 616 nm) was acquired upon the deposition of (MV, EuNap)CB[8]) due to the occurrence of surface energy transfer (SET). As a result, 1-(10-mercaptodecyl)-1'methyl-[4,4'-bipyridine]-diium bromide and 1-methyl-1'-(10-(naphthalen-2yloxy)decyl)-[4,4'bipyridine]-1,1'-diium bromide iodide were synthesised and the assembly of a molecular film envisaged in which the molecular recognition properties of CB[n] were maintained and significant optical output from the lanthanide ion (Eu3+, λem 616 nm) detected; the assembly of such a film centred on the formation of 1:2 intermolecular heteroternary complexes and the recruitment of EuNap at a distance ≥ 3.2 nm from the gold substrate. It was envisaged that the modulation of any emissive output would be brought about upon manipulating the oxidation state of a surface-confined metallocene. This thesis ends by summarising the research conducted and assessing how the inclusion chemistry of cucurbit[8]uril and the photophysical properties of the porphyrinic macrocycle can be combined in order to fabricate a dynamic, photoresponsive molecular assembly. The electrical energy generated from the efficient harvesting of light energy could be used in a multitude of applications, most notably as a nanoscale power supply to drive and control molecular and supramolecular actuations.

Doctor of Philosophy / Department of Chemical Engineering / Keith L. Hohn / The present work describes the conversion of bio-derived methyl ethyl ketone (MEK) into different useful chemicals. The first part discusses the direct conversion of MEK to butene over supported copper catalysts (Cu-Al₂O₃, Cu-zeolite Y sodium (Cu-ZYNa) and Cu-zeolite Y hydrogen (Cu-ZYH)) in a fixed bed reactor. In this reaction, MEK is hydrogenated to 2-butanol over metal sites, and further dehydrated on acid sites to produce butene. Experimental results showed that the selectivity of butene was the highest over Cu-ZYNa, and it was improved by finding the optimum reaction temperature, hydrogen pressure and the percentage of copper loaded on ZYNa. The highest selectivity of butene (97.9%) was obtained at 270 °C and 20 wt% Cu-ZYNa. Over Cu-Al₂O₃, the selectivity of butenes was less than Cu-ZYNa since subsequent hydrogenation of butene occurred to produce butane. It was also observed that with increasing H₂/MEK molar ratio, butane selectivity increased. However, when this ratio was decreased, hydrogenation of butene was reduced, but dimerization to C₈ alkenes and alkane began to be favored. The main products over 20% Cu-Al₂O₃ were butene and butane, and the maximum selectivity of butene (87%) was achieved at an H₂/MEK molar ratio of five. The lowest selectivity of butene was obtained using Cu-ZYH, reaching ~40%. It was found that the amount of acidity in Cu-ZYH is much higher than in Cu-ZYNa (from (NH₃-TPD) measurements). This could have caused the selectivity of butene to decrease as a result of dimerization, oligomerization and cracking reactions. The second part describes the conversion of MEK to higher ketones in one step using a multifunctional catalyst having both aldol condensation (aldolization and dehydration) and hydrogenation properties. 15% Cu supported zirconia (ZrO₂) was investigated in the catalytic gas phase reaction of MEK in a fixed bed reactor. The results showed that the main product was 5-methyl-3-heptanone in addition to 5-methyl-3-heptanol and 2-butanol with side products including other heavy products (C₁₂ and up). The effects of temperature and the molar ratio of reactants (H₂/MEK) on overall product selectivity were studied. It was found that with increasing temperature, the selectivity to C₈ ketone increased, while selectivity to 2-butanol decreased. The hydrogen pressure plays significant role on the selectivity of products. It was observed that with increasing the H₂/MEK molar ratio, 2-butanol selectivity increased due to hydrogenation reaction while decreasing this ratio leads to increasing aldol condensation products. In addition, it was noted that both conversion and selectivity to the main product increased using a low loading percentage of copper, 1% Cu-ZrO₂. The highest selectivity of 5-methyl-3-heptanone (~63%) was obtained at temperatures around 180 °C and a molar ratio of H₂/MEK of 2. Other metals (Ni, Pd and Pt) supported on ZrO₂ also produced 5-methyl 3-heptanone as the main product with slight differences in selectivity, suggesting that a hydrogenation catalyst is important for making the C₈ ketone, but the exact identity of the metal is less important. The third part discusses the conversion of C₈ ketones to C₈ alkenes and C₈ alkane over a catalyst consisting of a transition metal (Cu or Pt) loaded on alumina (Al₂O₃). These bifunctional catalysts provide both hydrogenation and dehydration functionalities. The main products over 20% Cu-Al₂O₃ were a mixture of 5-methyl-3-heptene, 5-methyl-2-heptene and 3-methyl heptane. However, using 1% Pt-Al₂O₃ the major product was 3-methyl heptane with a selectivity reaching over 97% and a conversion of 99.9 %. Both temperature and the hydrogen pressure play an important role on the conversion of C₈ ketone as well as the selectivity of products (C₈ alkenes and C₈ alkane). Over 20% Cu-Al₂O₃, it was observed that increasing the reaction temperature led to an increase in the selectivity to C₈ alkane as a result of hydrogenation of the C₈ alkene. Also, it was observed that with an increase in H₂/C₈ ketone molar ratio, C₈ alkane selectivity increased. However, when this ratio was decreased, the further hydrogenation of C₈ alkene to C₈ alkane was reduced. The highest selectivity of C₈ alkene (81.7%) was obtained at 220 °C and a H₂/C₈ ketone molar ratio of 2. In addition, an experiment was carried out using a low loading percentage of copper, and it was noted that both conversion and selectivity to the main products decreased over 1% Cu-Al₂O₃. Over 1% Pt-Al₂O₃, C₈ alkane was the major product with different temperatures indicating that further hydrogenation of C₈ alkene was promoted on 1% Pt-Al₂O₃. At low temperature, for both Cu-Al₂O₃ and Pt-Al₂O₃, significant amounts of C₈ alcohols are formed because subsequent reactions do not proceed at a fast enough rate. Also using 1% Pt-Al₂O₃, the main product selectivity is still C₈ alkane with all H₂/C₈ ketone ratios.

As Ceratoses Actínicas (CA) são lesões hiperceratóticas, displásicas de pele. Estão comumente localizadas em áreas expostas ao sol como couro cabeludo, face e antebraços. Acredita-se que a radiação ultravioleta (RUV) cumulativa seja o maior fator etiológico, considerando-se, também, a imunossupressão e infecção pelo papilomavírus humano(HPV) fatores contribuintes importantes. Existe o potencial de uma CA se transformar em Carcinoma Espinocelular (CEC) e, dessa forma, indica-se tratamento para as referidas lesões. Terapias tradicionais como crioterapia, curetagem e eletrocoagulação, medicações tópicas como 5-fluorouracil (5-FU) são ainda habituais. Porém novas opções como terapia fotodinâmica, diclofenaco e imiquimod 5% creme apresentam boa eficácia e perfil menor de efeitos colaterais, embora possam representar custo maior. A Terapia Fotodinâmica (TFD) envolve o uso de um agente fotossensibilizante, oxigênio e luz de comprimento de onda específico para causar morte celular. O fotossensibilizante geralmente utilizado é o ALA (ácido aminodeltalevulínico) ou seu éster metilaminolevulinato (MAL). No tecido lesionado, esses são convertidos em porfirinas fotoativas (PFAs) por enzimas da via biossintética do heme. A ativação é realizada por meio de luzes de comprimentos de onda que variam de 405 nm a 635 nm. Células displásicas ou neoplásicas produzem maior quantidade de porfirinas que os queratinócitos normais, sendo destruídas durante a aplicação da luz. O imiquimod 5% creme é um imunomodulador que estimula a resposta imune inata através da indução, síntese e liberação de citocinas. Isso resulta em efeitos antitumorais e antivirais indiretos. Seu uso tópico é eficaz e liberado para o tratamento de CA, Carcinoma Basocelular (CBC) superficial, Doença de Bowen (DB) e verrugas vulgares. Este trabalho tem como objetivo comparar duas recentes opções de tratamento para CA, a Terapia Fotodinâmica com metilaminolevulinato e o imiquimod 5% creme, por não existirem, na literatura atual, estudos comparativos dessas duas opções de tratamento. Foram selecionadas 12 pacientes com CAs que foram submetidas primeiramente à 1 sessão de TFD com MAL num lado da face e, 1 mês após, iniciaram o tratamento com imiquimod 5% creme aplicado no lado contralateral, duas vezes na semana, durante 16 semanas. A randomização foi realizada para determinar a hemiface para cada tratamento. Na primeira semana após a realização da TFD e mensalmente durante o tratamento com imiquimod, as pacientes foram avaliadas em relação aos efeitos colaterais dos tratamentos. Seis meses após entrarem no estudo, ambos os tratamentos foram analisados por um investigador cego para sua eficácia, tolerabilidade e seu resultado cosmético. Previamente ao tratamento as pacientes apresentaram um total de 245 lesões de CAs, sendo 120 lesões no lado submetido à TFD e 125 no lado tratado com imiquimod. Após o tratamento o número total de lesões diminuiu para 34 no lado tratado com TFD e para 30 no lado tratado com imiquimod, respectivamente. Não foram observadas diferenças estatisticamente significativas na eficácia de ambos os tratamentos e na frequência de efeitos colaterais. Entretanto, os pacientes, significativamente preferiram o tratamento com a terapia fotodinâmica, talvez pela rapidez do método, comparado com a aplicação tópica do creme de imiquimod a 5%. / Background: Actinic keratosis (AK) represents an initial process that may lead to in situ or invasive squamous cell carcinoma. The importance of its early diagnosis and treatment is well-established. There are several effective options available for the treatment of actinic keratosis, including topical imiquimod 5% cream and photodynamic therapy (PDT). Objetive: To compare the efficacy and patient preference between topical MAL-PDT and imiquimod 5% cream for the treatment of AK. Methods: Twelve patients, with a total of 245 lesions, underwent treatment with MAL-PDT and imiquimod 5% cream. Randomization was performed to determine the hemiface (right or left) for each therapy. First, patients were submitted to MAL-PDT. After one month, they started to use imiquimod on the opposite side of the face, twice a week, for 16 weeks. Six months after entering the study, both treatments were analyzed by a blinded investigator for their effectiveness, tolerability and cosmetic result. Results: Both treatments showed a good therapeutic response. 72% of the lesions treated with MAL-PDT were completely cleared, and 76% of those treated with imiquimod. The mean size of the residual lesions after the treatments was similar. Ten patients (83%) preferred MAL-PDT rather than imiquimod. (p: 0.03). Conclusions: Both MAL-PDT and imiquimod are effective in clearing AKs. Our results showed similar efficacy and good cosmetic outcomes with both treatments. However, a significant percentage of the subjects preferred MAL – PDT.