Carbonyl sulfide (OCS) is emitted to the atmosphere through the outgassing of ocean surface waters. OCS is also the primary source of sulfur-containing compounds in the stratosphere and contributes to the formation of the stratospheric sulfate layer, an essential controller of the radiative balance of the atmosphere. During the 2016 Student Airborne Research Program (SARP), 15 whole air samples were collected on the NASA DC-8 aircraft over the Santa Barbara Channel. Five additional surface samples were taken at various locations along the Santa Barbara Channel. The samples were analyzed using gas chromatography in the Rowland-Blake lab at UC Irvine, and compounds associated with ocean emissions including OCS, dimethyl sulfide (DMS), carbon disulfide (CS2), bromoform (CHBr3), and methyl iodide (CH3I) were examined. Excluding OCS, the vertical distribution of marine tracers that were analyzed showed dilution with increasing altitude. For OCS, the surface samples all exhibited elevated concentrations of OCS in comparison to samples taken from the aircraft, with an average of 666 ± 26 pptv, whereas the average concentration of OCS in the aircraft samples was 581 ± 9 pptv. 2016 Surface samples were compared to surface samples from SARP campaigns between 2009-2015 taken near or within the 2016 study region. The 2009-2015 samples exhibited an average OCS concentration of 526 ± 8 pptv. It is evident that the 2016 surface samples measured higher concentrations of OCS than ever recorded during previous SARP campaigns and in comparison to global averages: 525 ± 17 pptv in the Northern hemisphere and 482 ± 13 pptv in the Southern hemisphere (Sturges et al., 2001). OCS emissions should be measured using surface samples if emission estimates from the ocean are to be evaluated since measurements from the aircraft (500 ft) are not sufficiently capturing surface concentrations. Additionally, OCS enhancements seen in 2016 had never before been detected by surface samples, revealing a potential phenomenon at work causing the elevation during this year’s campaign.

In Säugetieren existieren im wesentlichen zwei Abwehrsysteme gegen oxidativen Streß, in welchen die Glutathionreduktase (GR) und Thioredoxinreduktase (TrxR) Schlüsselenzyme sind. Ein einzelnes Gen der Taufliege, genannt dmtrxr-1, kodiert sowohl für die durch alternatives Splicing entstehende cytoplasmatische und mitochondriale Form der DmTrxR-1. Zum Teil innerhalb des dmtrxr-1-Gens findet sich auf dem Komplementärstrang ein weiteres Gen, welches sniffer genannt wurde. In Kooperation wurde nachgewiesen, daß dieses Gen essentiell zur Verhinderung alterungsbedingter Neurodegeneration ist. Durch biochemische Charakterisierung konnte das rekombinant hergestellte Produkt dieses Gens in der vorliegenden Arbeit als Carbonylreduktase, ein zu den Kurzketten-Dehydrogenasen (short-chain dehydrogenases) gehörendes Enzym, identifiziert werden. Sniffer weist das für Carbonylreduktasen typische Substratspektrum mit Phenanthrenequinone als bestem Substrat auf und wird von Flavonoiden wie Quercetin und Rutin sowie Hydroxymercuribenzoat gehemmt. In verschiedenen Ansätzen konnten Kristalle des rekombinanten Proteins gewonnen werden, die inzwischen in Kooperation vermessen wurden und so zu einer Kristallstruktur mit einer Auflösung von 1,7 Angström führten. Durch diese Arbeiten konnte zum ersten Mal eine Verbindung zwischen einem charakterisierten Gen (snifffer), oxidativem Streß und neurodegenerativen Effekten auf molekularer Ebene nachgewiesen werden. Parasiten haben während ihres Lebenszyklus einen hohen Bedarf an Energie und sind abhängig von einer starken Syntheseleistung. Zur Bewältigung dieses Stresses benötigen sie hohe Aktivitäten an Adenylatkinase (AK; ATP + AMP  2 ADP) und GTP-AMP-Phosphotransferase (GAK; GTP + AMP  GDP + ADP). Beide Enzyme wurden in Blutstadien des Malariaparasiten Plasmodium falciparum identifiziert und die entsprechenden Gene der PfAK und PfGAK auf den Chromosomen 10 und 4 respektive lokalisiert. Klonierung und heterologe Expression in E. coli ergab enzymatisch aktive Proteine mit einer Größe von 28,9 (PfAK), bzw. 28,0 kDa (PfGAK). Das rekombinante Protein der PfAK entspricht in seinen biochemischen Charakteristika denen der authentischen PfAK. Dies gilt auch für eine mögliche Assoziation mit einem stabilisierenden Protein mit einem Molekulargewicht von ca. 70 kDa und der hohen Substratspezifität für das Monophosphat-Nukleotid AMP. Die Spezifität für das Triphosphat-Substrat ist weniger stringent. Das beste Triphosphat-Substrat ist ATP mit einem Vmax-Wert von 75 U/mg und einem kcat von 2800 min-1. Die Sequenz der PfAK enthält eine amphiphatische Helix, welche als notwendig für die Translokation zytosolischer Adenylatkinasen in den Intermembranraum der Mitochondrien beschrieben wurde. Die PfGAK bevorzugt GTP und AMP als Substrat (100 U/mg; kcat = 2800 min-1 bei 25°C) und zeigt als Besonderheit keine messbare Aktivität mit ATP. Im Gegensatz zu ihrem Ortholog im Menschen (AK3) enthält die Sequenz der PfGAK ein Zinkfinger-Motiv und bindet Eisenionen. Erste Immunfluoreszenz-Analysen lokalisieren die PfGAK in den Mitochondrien. PfAK und PfGAK werden von den Dinukleosid-Pentaphosphat-Verbindungen AP5A beziehungsweise GP5A gehemmt. Die Ki-Werte liegen mit ca. 0.2 µM ungefähr 250-fach niedriger als die KM-Werte der entsprechenden Nukleotidsubstrate. Zur Lösung der vor allem im Rahmen einer rationalen Medikamentenentwicklung notwendigen Kristallstruktur des Zielmoleküls konnten bereits Kristalle der PfGAK erhalten werden. / In mammalia, two major systems with glutathione reductase (GR) and thioredoxin reductase (TrxR) as key enzymes defend the organism against oxidative stress. The single copy gene dmtrxr-1 codes for both the cytoplasmic and mitochondrial form of DmTrxR-1, generated by alternative splicing. Another gene, located on the complementary strand partially within the dmtrxr-1 gene, could be identified and was named sniffer. This gene is essential for prevention of age-related neuro-degeneration, as could be shown in a cooperation with the group of Prof. Schneuwly. In this thesis, biochemical characterization of the recombinant protein identified sniffer as a carbonyl reductase, an enzyme belonging to the short-chain-dehydrogenases. Sniffer shows the typical substrate spectrum of carbonyl reductases with phenthrenequinone as best substrate and is inhibited by the flavonoids quercetin and rutin and also by hydroxymercurybenzoate (HMB). Protein crystals could be obtained under different conditions. In a cooperation with the group of Prof. Klebe, these already lead to a crystal structure with a resolution of 1.7 angstrom. The work on sniffer is the first that directly links a characterized gene (sniffer), oxidative stress and neurodegeneration on the molecular level. For coping with energetic and synthetic challenges, parasites require high activities of adenylate kinase (AK; ATP + AMP  2 ADP) and GTP:AMP phosphotransferase (GAK; GTP + AMP  2 ADP). These enzymes were identified in bloodstream stages of Plasmodium falciparum. The genes encoding PfAK and PfGAK are located on chromosomes 10 and 4, respectively. Molecular cloning and heterologous expression in E. coli yielded enzymatically active proteins of 28.9 (PfAK) and 28.0 kDa (PfGAK). Recombinant PfAK resembles authentic PfAK in its biochemical characteristics including the possible association with a stabilizing protein and the high specificity for AMP as the mononucleotide substrate. Specificity is less stringent for the triphosphate, with ATP as the best substrate (75 U/mg; kcat = 2160 min-1). PfAK contains the sequence of the amphiphatic helix that is known to mediate translocation of the cytosolic protein into the mitochondrial intermembrane space. PfGAK exhibits substrate preference for GTP and AMP (100 U/mg; kcat = 2800 min-1); notably, there is no detectable activity with ATP. In contrast to its human orthologue (AK3), PfGAK contains a zinc finger motif and binds ionic iron. The dinucleoside pentaphosphate compounds AP5A and GP5A inhibited PfAK and PfGAK, respectively, with Ki values of appr. 0.2 µM which is more than 250-fold lower than the KM values determined for the nucleotide substrates. The disubstrate inhibitors are useful for studying the enzymatic mechanism of PfAK and PfGAK as well as their function in adenine nucleotide homeostasis; in addition, the chimeric inhibitors represent interesting lead compounds for developing nucleosides to be used as antiparasitic agents. To elucidate the structure which is necessary for the use as a drug target, crystallization studies have been performed and the first crystals could be obtained.

Student Number : 0009404H - PhD thesis - School of Chemistry - Faculty of Science / Six-coordinate ruthenium complexes of the type ttt-RuX2(RNC)2(PPh3)2 (X = Cl ; R = tBu, 2,6-xylyl, benzyl, 2-OMe-4-Clphenyl and iPr; X = Br; R = = tBu, 2,6-xylyl, benzyl, iPr ) were synthesized and fully characterised by IR, NMR spectroscopy and elemental analysis. These complexes were all found to undergo solid-state isomerisation from the ttt-isomer to the cct-isomer. It was found that solid state isomerisation occurred before melting i.e. in the solid state for all the ttt-RuX2(RNC)2(PPh3)2 complexes investigated . The thermal solid state isomerisation process was monitored by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomicroscopy and X-ray powder diffraction techniques. The results revealed that the isomerisation process occurred exothermally with darkening of the crystal. A mechanism which involved rotation of small ligands was proposed to explain the solid-state isomerisation process. Kinetic studies of the solid-state isomerisation of some of the ttt-RuCl2(RNC)2(PPh3)2 complexes were carried out and monitored by NMR spectroscopy and compared with kinetic studies performed by XRD methods. The results are similar and also suggest that the isomerisation reaction follows first order kinetics. The crystal and molecular structure of ttt-RuCl2(2,6-xylylNC)2(PPh3)2 was determined by X-ray single crystal diffraction techniques and its structure was compared with related ttt- RuX2(RNC)2(PPh3)2 complexes. Inter-molecular and intra-molecular interactions in these molecules in the solid state were analysed and used to rationalise the solid-state isomerisation results. The results obtained for the ruthenium complexes suggested that other six-coordinate complexes could undergo solid state isomerisation reactions and this study was extended to molybdenum complexes of the type cis-Mo(CO)4L2. These complexes undergo cis to trans isomerisation in solution. The solid state reactivity of these complexes was investigated for the first time. The complexes with L = PPh2Me and PPh2Et isomerised in the melt whist complexes with L = PPh3 amd P(m-tolyl)3 were indeed found to undergo solid state isomerisation reactions. Structural studies and thermomicroscopic investigations were done on cis- Mo(CO)4(PPh3)2 and Mo(CO)4{P(m-tolyl)3)2 and the results were used to rationalize the solid state reactivity of these complexes.

The conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordination followed by a base-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. Chiral amidine and chiral DBU derivatives were synthesized to carry out the isomerization enantioselectively. We employed HPLC equipped with a chiral column to determine the enantiomeric excess. We also proved that the mechanism of that the manganese-coordinated alkyne/allene rearrangement reaction involved an intermediate cumenolate. It was also confirmed that amine base with pKa lower than that of DBU (pKa = 13.6) would not carry out the isomerization. Alkoxy base were also used in isomerization and the mechanism was also investigated. / by Chang He. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Não consta resumo na publicação. / Abstracts nor available.

This thesis details the development and exploration of a catalytic carbonyl-olefin metathesis reaction. A catalytic transformation of this type has not been accomplished previously and stoichiometric processes were neither general nor desirable. A simple hydrazine catalyst was found to effect this reaction with the use of strained olefins. The development and optimization of this reaction, including the hydrazine catalyst, conditions and substrates, is discussed. Computational studies of the reaction mechanism are included. A stepwise process in which less strained olefins can undergo the reaction is also explored. Lastly, some initial explorations of transition metal complexes as catalysts for a carbonyl-olefin metathesis reaction are discussed, as well. In the second portion of this thesis, the use of cyclopropenimines as achiral organic superbases will be detailed. Previously, the Lambert group has developed this class of compounds as viable catalysts for asymmetric Michael and Mannich reactions. Cyclopropenimines are more basic than other commonly used organic bases, and therefore, can activate less acidic substrates. A simple, achiral cyclopropenimine was developed for use in base catalyzed or mediated processes. Several reactions have been explored as a comparison of cyclopropenimines to other commonly used bases.

Na última década, a utilização de misturas de gasolina e etanol em qualquer proporção como combustível em veículos do tipo “flex” aumentou de forma significativa no Brasil. Compostos Carbonílicos (CC) pertencem a uma importante classe de poluentes emitidos pela frota veicular. A cidade de São Paulo, Brasil, tem 9,2 milhões de veículos, os quais afetam diretamente a qualidade do ar. Neste trabalho, foi determinada a concentração de quatorze CC na atmosfera, em três diferentes sítios de amostragem localizados na zona oeste da cidade de São Paulo, dois nos campus da Cidade Universitária: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG) e Instituto de Ciências Biomédicas (ICB) e um em Cerqueira César, Faculdade de Saúde Pública (FSP), no período de 2008/2009. Os CC foram coletados em cartucho de sílicagel, impregnada com 2,4-dinitrofenilhidrazina e analisados por Cromatografia Líquida de Alta Eficiência (CLAE) com detecção UV-visível. O conjunto de dados gerado foi caracterizado aplicando Análise de Componentes Principais (PCA) e Análise de Agrupamentos Hierárquicos (HCA). Foi utilizado o cromatograma completo, uma abordagem quimiométrica ainda não utilizada para avaliação de CC na atmosfera. Os cromatogramas das amostras foram alinhados utilizando os algoritmos Peakmatch e Optim_COW, deslocamentos de linha base e ruído foram removidos empregando, respectivamente, a primeira derivada e o método de ajuste polinomial de Savitzky- Golay. As amostras coletadas nos três sítios apresentaram contrações significativas de formaldeído (F), acetaldeído (A) e acetona e concentrações menores de butiraldeído, benzaldeído, valeraldeído e propionaldeído. A quantidade de acetaldeído foi superior à de formaldeído para a maioria das amostras, levando a uma razão F/A menor do que 1, fato que tem sido atribuído ao uso de etanol em larga escala como combustível veicular. Na análise univariada, foi observado um perfil semelhante nos gráficos de concentração dos CC em qualquer um dos sítios de amostragem. Na análise multivariada por PCA, a PC1 representou a quase totalidade da variação experimental (97,6%). Estes resultados podem sugerir a presença de uma única fonte de emissão. O gráfico de scores da PCA e o dendograma da HCA indicaram a formação de dois agrupamentos: um formado pelas amostras FSP e IAG e outro pelas amostras ICB. O gráfico de loadings da PCA indicou que as diferenças são devidas à concentração de todos os CC. A separação das amostras ICB das demais pode ser explicada pelas diferentes condições meteorológicas observadas no sítio ICB / In the last decade, the use of ethanol-blended-gasoline in any proportion as fuel in light vehicles (flex fuel) has significantly increased in Brazil. Carbonyl compounds (CC) are an important class of vehicular total hydrocarbons emission. São Paulo City, Brazil, has 9,2 million vehicles that directly affect the air quality. In this work, the concentration of fourteen CCs in the air of three different sites of São Paulo city was determined during 2008/2009. Two sites (IAG and ICB) were located inside São Paulo University whereas a third one was located in Cerqueira César (FSP). Compounds were collected in a silica-gel cartridge coated with 2,4-dinitro-phenylhydrazine and analyzed by CLAE with UV-Vis detection (365 nm). The sites were characterized by Principal Component Analysis (PCA) and Hierarquical Cluster Analysis (HCA). The entire chromatogram was used to multivariate calculations, which represents an innovative approach in CC studies. Chromatograms of the samples were aligned using the Optim_COW and Peakmatch algorithms, the baseline was corrected by the first derivative and instrumental noise was removed by Savitzky-Golay polynomial fit. The samples collected at the three sites presented different amounts of formaldehyde (F), acetaldehyde (A) and ketone and minor concentrations of butiraldehyde, benzaldehyde, valeraldehyde and propionaldehyde. The acetaldehyde content was observed to be superior to the formaldehyde, so that the F/A was lower than 1 for all sites. This fact can be related to the increasing use of ethanol as fuel. It was observed a similar profile of CC concentration in all sites studied. In PCA analysis, only one Principal Component could describe a large amount of experimental variability (97.57 %), indicating that a single emission source (vehicular) might have been present. The PCA scores graph and HCA dendogram pointed out that samples from FSP and IAG were similar whereas samples from ICB presented a different behavior. The loadings graph indicated that those differences were due to concentration of all CC. This fact could be due to different climatic conditions during sampling

Selenium (Se) is an essential mineral with functions for both animals and humans. There are several regions in the world deficient in this mineral and studies have related Se supplemented with reducing cholesterol. Thus, the objective of this study was to evaluate the Se effect in different levels and sources in the diet finishing of Nellore cattle on the performance and meat quality. It was used 63 Nellore cattle (412 kg and ± 24 months of age) in a completely randomized design with two sources (sodium selenite and selenium-enriched yeast) and four supplementation levels (0; 0.3; 0.9 and 2.7 mg Se/kg DM). There were no changes in performance and carcass characteristics. The Se level reduced (P<0.01) lipid and proteins oxidation (TBARS and carbonyl) compared to the control treatment on retail display storage (0, 2, 4 and 6 days). Organic Se, regardless of level, provided Se 138% higher (P<0.0001) in meat and 22.6% higher (P<0.0001) in serum than inorganic Se. The activity of glutathione peroxides (GPx) in muscle was 288% higher for animals supplemented with selenium and consequently, the cholesterol concentration in L. dorsi was 10.2% lower (P<0.001). The serum HMG-CoA reductase concentration was 32.7% lower in animals receiving Se supplementation (organic or inorganic). In conclusion, Se supplementation in beef cattle diet is a way of naturally producing selenium-enriched meat and with better quality for human consumption. / O selênio (Se) é um mineral essencial com funções para animais e humanos. Existem várias regiões do mundo deficientes neste mineral e estudos têm relacionado a suplementação de Se com a redução do colesterol. Assim, o objetivo deste estudo foi avaliar o efeito de diferentes teores e fontes de Se na dieta de terminação de bovinos Nelore sobre o desempenho e a qualidade da carne. Foram utilizados 63 animais da raça Nelore (412 kg e ± 24 meses de idade) em delineamento inteiramente casualizado, com duas fontes (selenito de sódio e selênio levedura) e quatro teores de suplementação (0; 0,3; 0,9 e 2,7 mg Se/kg MS) em confinamento, durante 84 dias. Não houve alterações no desempenho e nas características de carcaça. O teor de Se reduziu (P <0,01) a oxidação lipídica e proteica (TBARS e carbonila) em comparação ao tratamento controle durante o armazenamento em simulação de exposição no varejo (0, 2, 4 e 6 dias). O Se orgânico, independentemente do teor, forneceu valor de Se 138% superior (P <0,0001) na carne e 22,6% superior (P <0,0001) no soro em relação ao Se inorgânico. A atividade glutationa peroxidase (GPx) no músculo foi 288% maior nos animais suplementados com selênio e, consequentemente, a concentração de colesterol na carne foi 10,2% menor (P <0,001). A concentração sérica de HMG-CoA redutase foi 32,7% menor nos animais que receberam suplementação de Se (orgânico ou inorgânico). Foi concluído que a suplementação com Se na dieta de bovinos de corte é uma forma de produzir carnes enriquecidas com selênio naturalmente e com melhor qualidade para consumo humano.

Thesis (Ph. D.)--University of Wyoming, 2006. / Title from PDF title page (viewed on Dec. 21, 2007). Includes bibliographical references.

High resolution solar spectra are routinely recorded since more than two decades by the University of Liège at the International Scientific Station of the Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580 m asl) with Fourier Transform Infrared (FTIR) spectrometers. Over the last years, major improvements have been implemented in the algorithms used to retrieve the abundances of atmospheric constituents accessible to the FTIR technique. Now, in addition to total column, information on the vertical distribution of the target gas is often available, allowing producing partial column data sets. We take advantage of these improvements to generate and characterize long-term total and partial columns time series of some important inorganic fluorinated trace gases deduced from FTIR measurements performed at Jungfraujoch. First, our investigations on hydrogen fluoride (HF) indicate that the adoption of a Galatry line shape model for this species significantly improves the fitting quality of the retrievals. The sensitivity of our FTIR measurements to HF inversions in three distinct regions that range from the low to the high stratosphere is confirmed thanks to products derived from two satellites and from two numerical models. We further demonstrate that the HF seasonal variations that occur in the low stratosphere are mainly responsible for the seasonal cycle observed in our HF total column time series. We have also developed an original multi-spectrum multi-window retrieval strategy allowing to derive, for the first time, some information on the vertical distribution of carbonyl fluoride (COF2) from ground-based FTIR measurements. After comparison with model data, our COF2 and HF FTIR datasets are combined to assess the atmospheric inorganic fluorine burden Fy. A trend analysis of our HF, COF2 and Fy time series is then performed for four different time periods spanning the 1985-2010 time interval. While we observe a recent stabilization for HF, corresponding COF2 data show a significant rise, after a period of significant reduction in its accumulation rate. This is probably ascribable to the combination of the decrease of its main source gas CFC-12 with the increase of the substitute product HCFC-22. However, this increase in the COF2 rate of change does not significantly impact the Fy trend, which is essentially driven by the change in HF. In addition, we show that the partitioning between the two major fluorine reservoirs HF and COF2 has not changed since the beginning of this century. Together, they account for around 95% of total inorganic fluorine in the atmosphere. Finally, we study the long-term evolution of carbon tetrafluoride (CF4), for the first time from ground-based FTIR measurements. The trend analysis of our time series indicates a slowing, initiated during the nineties, in the CF4 growth rate despite the fact that the absolute loading of this compound is still increasing. Our linear accumulation rates are consistent with those deduced from space or surface measurements.