The cycling of biogenic volatile sulfur compounds (VSCs) within marine and terrestrial ecosystems has been shown to play an integral role in atmospheric chemistry; by influencing global climate change through the creation of cloud condensation nuclei and controlling acid-base chemistry; as well as influencing sediment chemistry including the interactions with trace metals, particularly regarding iron sulfide formation. Despite this, the examination of VSCs within Australian coastal acid sulfate soils (ASS) is an unexplored area of research. As ASS in Australia occupy an area in excess of 9 M ha, there is a clear need for a greater understanding of the cycling of these compounds within such systems. This thesis looks at the concentrations of several VSCs within agricultural and undisturbed ASS on the east coast of Australia. Initial measurements of sulfur dioxide (SO2) were made using passive diffusion samplers, which were followed by two detailed field-based studies looking at the concentrations and fluxes of both SO2 and hydrogen sulfide (H2S) using flux-gradient micrometeorological techniques. These novel results indicated that this agricultural ASS was a substantial source of atmospheric H2S (0.036-0.056 gSm-2yr-1), and SO2 (0.095-0.31 gSm-2yr-1), with flux values equating to many other salt- and freshwater marshes and swamps. The flux data also suggested that the ASS could be a continual source of H2S which is photo-oxidised during the daytime to SO2. Measurements of both compounds showed separate, inverse correlations to temperature and moisture meteorological parameters indicating possible contributing and / or causal release factors. Further identification of these and other VSCs within ASS samplers was undertaken in the laboratory using gas chromatography in combination with solid-phase microextraction. Although SO2 and H2S were not discovered within the headspace samples, two other VSCs important in atmospheric sulfur cycling and trace metal geochemistry were quantified; dimethylsulfide (DMS; &gt 300??g/L) and ethanethiol (ESH &gt 4??g/L). The measurements of H2S, DMS and ESH are the first quantifications with Australian ASS, and they may be important for refining regional or local atmospheric sulfur budgets, as well as interpreting previous SO2 emissions from ASS. Ultimately this thesis further enhances our understanding of the cycling of VSCs within acid sulfate systems.

As energias alternativas avançam mundialmente devido aos problemas ambientais resultantes da obtenção e uso das fontes energéticas convencionais. Um combustível alternativo relevante, proveniente do tratamento anaeróbio, de resíduos ou efluentes, é o biogás. O biogás, devido à sua concentração de metano (CH4), tem sido usado para a geração de energia elétrica. Entretanto, a eficiência do processo é reduzida em função das elevadas concentrações de dióxido de carbono (CO2) e sulfeto de hidrogênio (H2S). O CO2 reduz o poder calorífico do biogás e o H2S tem efeito corrosivo nas estruturas de produção e conversão de energia. Portanto é importante o desenvolvimento de tecnologias que auxiliem na redução destes dois gases no biogás. O presente trabalho teve como objetivo investigar as influências da concentração de soluções contendo ferro (Fe) quelado com EDTA (Fe/EDTA) e da razão entre vazão de líquido e biogás (L/G), em contracorrente em uma torre de absorção, na remoção do CO2 e do H2S. Para avaliar as eficiências de remoção a diferentes condições operacionais, foi proposto um Delineamento Composto Central Rotacional (DCCR) 22, com três experimentos nos pontos centrais e quatro nos pontos axiais. Nos ensaios realizados, as concentrações de Fe/EDTA foram avaliadas entre 0,100 e 0,200 mol.L-1 e a razão L/G entre 0,73 e 1,27. Para o H2S, na faixa de valores estudada, as duas variáveis, concentração de Fe/EDTA e L/G, foram significativas (p<0,05) e a máxima eficiência foi de 97,84%. Em relação ao CO2, nas mesmas condições, a eficiência alcançada foi de 18,19%. A partir da análise dos resultados obtidos, com remoções elevadas para o H2S e satisfatórias para o CO2, pode-se concluir, de forma geral, que esse processo de purificação de biogás permite uma melhora na qualidade do biogás como combustível e reduz, eficientemente, as quantidades de H2S para níveis que causam poucos danos ao processo. / Alternative energy advances worldwide due to environmental problems resulting from the collection and use of conventional energy sources. An important alternative fuel, from the anaerobic treatment of waste or effluent, is biogas. Biogas because of its concentration of methane (CH4), has been used to generate electricity. However, the process efficiency is reduced due to high concentrations of carbon dioxide (CO2) and hydrogen sulfide (H2S). The CO2 reduces the calorific value of biogas and H2S has corrosive effect on production and energy conversion structures. Therefore, it is important to develop technologies that help reduce these two gases in biogas. This study aimed to investigate the influences of solutions containing chelated iron (Fe) with EDTA (Fe / EDTA) and the ratio of liquid flow and biogas (L / G), countercurrent in a tower absorption in removal of CO2 and H2S. To evaluate the removal efficiencies at different operating conditions, it was proposed a Central Composite Rotational Design (CCRD) 2², with three experiments in the central point and four in axial points. In the tests performed, the Fe/EDTA concentrations were adjusted between 0.100 and 0.200 mol L-1 and L/G ratio between 0.73 and 1.27. For the H2S in the range of values studied, the two variables, the concentration of Fe/EDTA and L/G were significant (p < 0.05) and the maximum efficiency was 97.84%. In relation to CO2 under the same conditions, the efficiency achieved was 18.19%. From analysis of the results with high removals for H2S and satisfactory for CO2, it can be concluded in general that this process of biogas purification allows an improvement in the quality of the biogas as a fuel and reduces efficiently the quantities H2S at levels that cause little harm to the process.

As fontes hídricas disponíveis para o consumo humano vêm sendo comprometidas. Para resolver este problema, várias técnicas de detecção de contaminação fecal foram desenvolvidas. Em 1982, Manja e colegas desenvolveram método H2S que é simples, rápida e de baixo custo e detecta bactérias produtoras de H2S e, assim, a contaminação fecal. Neste trabalho foi analisada a eficácia de detecção de micro-organismos produtores de H2S frente a adição de L-cistina (125mg/L e 250mg/L) e desoxicolato de sódio (DS) (0,1% e 0,3%) e na presença de bactérias não produtoras de H2S para verificar se a presença destas bactérias interferem na detecção dos isolados H2S+. Assim, comparou-se o teste H2S com a membrana filtrante e o Colilert®. Os resultados deste estudo indicam que o meio H2S com adição de 0,3% de desoxicolato de sódio se mostrou mais rápido e sensível. Quando comparado com outras metodologias clássicas, o meio com 0,3% apresentou uma ligeira queda na sensibilidade mas o método H2S se mostrou mais sensível que o Colilert. / Water supply for human consumption have been compromised. Several detection methods for fecal contamination have been developed to solve this problem. Manja and co-workers (1982) developed a simple, fast and low-cost method for fecal contamination based on detection of sulfate-reducing bacteria, the H2S method. This work aimed to analyse the detection efficiency of the H2S method under different conditions: with L-cystine (125mg/L e 250mg/L) and sodium deoxycholate (0.1% e 0.3%). Also, non-sulfate-reducing bacteria interference were evaluated. Comparison tests were made through membrane filtration and Colilert®. Our results indicate a faster and more sensible for the 0.3% sodium deoxycholate condition. Compared to other classic methodologies, the 0.3% sodium deoxycholate condition slightly decrease the sensibility. However the H2S method was more sensitive than the Colilert one.

In the early 1990’s, a lot of work was focused on extending the kraft cook to a low lignin content (low kappa number). The driving force was the need to further reduce the environmental impact of the bleaching, as less delignification work would be needed there. However, the delignification during the residual phase of a kraft cook is very slow and, due to its poor selectivity, it is a limiting factor for the lignin removal. If the amount of lignin reacting according to the residual phase could be reduced, it would be possible to improve the selectivity of the kraft cook. In the work described in this thesis, special attention has been given to the activation energy of the slowly reacting residual phase of a kraft cook on softwood raw material and to the influence of different cooking parameters on the amount of the residual phase lignin. The activation energy of the residual phase delignification of the kraft cook was shown to be higher than that of the bulk phase delignification. In order to decrease the amount of residual phase lignin, it was essential to have a high concentration of hydrogen sulphide ions when cooking with a low hydroxide concentration. It was also important to avoid a high sodium ion concentration when cooking with low hydroxide and low hydrogen sulphide ion concentrations. Furthermore, it was demonstrated that dissolved wood components had a positive effect on the delignification rate in the bulk phase of a kraft cook. The influence of different cooking parameters in the extended softwood kraft process on the bleachability (i.e. the ease with which the pulps can be bleached to a target brightness) of the manufactured pulp was also investigated. If variations in bleachability were seen, an attempt would also be made to find chemical reasons to explain the differences. It was difficult to establish clear relationships between the chemical structures of the residual lignin and the bleachability of the pulp. However, it was seen that the higher the content of β-aryl ether structures in the residual lignin after cooking, the better was the QPQP*-bleachability. In the middle/end of the 1990’s, the focus moved from extended cooking to efficient utilisation of the wood raw material, e.g. by interrupting the kraft cook at higher kappa number levels and choosing appropriate cooking conditions to maximise the cooking yield. A high cooking yield often leads to a somewhat higher hexenuronic acid (HexA) content of the pulp at a given kappa number. Therefore additional attention was devoted to how the HexA content and carbohydrate composition were affected, e.g. by a set of cooking parameters. Performing these studies it was also important to investigate the effects of a low HexA (after cooking) strategy on such vital factors as the cooking yield, the bleachability and the yellowing characteristics of the pulp obtained. It proved to be difficult to significantly reduce the HexA content in a kraft pulp by altering the cooking conditions for both softwood and the hardwood Eucalyptus Globulus. A reduction in HexA content can be achieved by extending the cook to lower kappa numbers, or by using a high hydroxide concentration, a low hydrogen sulphide concentration or a high sodium ion concentration. However, neither of these strategies is attractive for industrial implementation since they would result in an extensive loss of yield, viscosity and strength. / <p>QC 20100825</p>

Ganglion cell death in glaucoma is caused by a variety of insults that include ischemia, insufficient neurotrophic support and oxidative stress. Experimental studies were therefore conducted on cell cultures to determine how serum deprivation (to mimic insufficient neurotrophic support) or oxidative glutamate toxicity (GB), cause oxidative stress and induce retinal cell death. Moreover, studies were carried out to deduce whether selected sulphur containing compounds can blunt any negative influences to cells in culture and/or a defined ischaemic insult to the rat retina in situ, as this might suggest their use for the treatment of glaucoma. Serum deprivation and GB caused generation of reactive oxygen species (ROS) and apoptosis-like death to transformed retinal ganglion cells (RGC-5 cells). RGC-5 cells were more susceptible to the detrimental effects of GB than serum deprivation. RGC-5 cells subjected to serum deprivation appear to die by mechanisms that resemble classical apoptosis more closely than that caused by GB and the phase between the maximal generation of ROS and cell death were different. Cell death caused by serum deprivation was caspase-dependent but this was not the case for GB. Moreover, of the two sulphur compounds sulbutiamine and N-acetyl cysteine (NAC), sulbutiamine blunts the effect of serum deprivation more effectively. In addition, the pan caspase inhibitor z-VAD-fmk attenuated the negative effect of serum deprivation to RGC-5 cells while the necroptosis inhibitor (necrostsatin-1) counteracted solely the insult of GB. The sulphur containing compounds, ACS1 and ACS 67 which release hydrogen sulphide (H2S) slowly and NAC (a pro-cysteine GSH precursor) attenuated GB-induced cell death of RGC-5 cells. In contrast, sulbutiamine (a lipophilic thiolic thiamine derivative) was particularly effective in protecting RGC-5 cells from an insult of serum deprivation. Moreover, all of the sulphur compounds directly sequestered different types of ROS but with varying efficiency. Common features by which all tested sulphur containing agents seem to elicit a mode of action include the stimulation of GSH and the antioxidant enzyme glutathione-S-transferase (GST) as well as to scavenge excess free radicals. Moreover, the slow release of H₂S from the ACS compounds appears to protect cells from oxidative stress through increasing the level of GSH, modulation of the cystine uptake transporter xCT, stimulation of the oxidative stress related transcription factor Nrf2 and the stimulation of pro-survival signalling pathways. The slow releasing H₂S sulphur compound ACS67 also counteracts a number of detrimental influences to the rat retina in situ because of ischemia/reperfusion that includes damage to their ganglion cells. This suggests that such sulphur compounds might find a use in the treatment of glaucoma where ischemia probably plays a part in the disease process.

O prurido, assim como a dor, é uma experiência sensorial aversiva, associada ao desejo de coçar-se. Resultados prévios deste grupo demonstraram que a injeção i.d. de moléculas doadoras do sulfeto de hidrogênio (H2S), um novo mediador endógeno, reduziu o prurido agudo e a inflamação cutânea induzidos por histamina ou composto 48/80 (C48/80) na pele dorsal de camundongos, sugerindo o envolvimento do H2S no controle do prurido mediado por aminas. Todavia, pouco se conhece sobre os mecanismos envolvidos na indução ou inibição dessa percepção sensorial (aguda ou crônica), e a participação do H2S. A fim de aprofundar esse conhecimento, os objetivos deste estudo foram:i) testar e caracterizar os mecanismos envolvidos nos efeitos protetores de diferentes moléculas doadoras de H2S (liberação rápida e lenta) sobre o prurido agudo e inflamação associada, induzidos por estímulos dependente e independente de histamina, ii) averiguar a capacidade de produção endógena de H2S e as enzimas envolvidas em sua síntese na pele murina saudável e doente, iii) padronizar um modelo de prurido crônico associado ao escore de intensidade da área inflamada na psoríase (PASI), e investigar o efeito protetor de um doador de H2S de liberação lenta (GYY4137). Utilizando camundongos Balb/C, foi realizada a avaliação do comportamento de prurido agudo e inflamação cutânea (extravasamento plasmático, influxo de neutrófilos), frente a diversos estímulos, na ausência e vigência do co- tratamento (i.d.) com doadores de H2S. A psoríase experimental foi induzida pela aplicação tópica do creme imiquimode (IMQ 5%) na pele dorsal destes, por 5 dias consecutivos, e grupos paralelos com a doença foram tratados pela via intraperitoneal (i.p.) com o GYY4137 em diferentes doses (25-100 mg/kg). Os registros do prurido e PASI foram obtidos durante a indução da psoríase e as análises bioquímicas e moleculares foram realizadas ao término do experimento. O tratamento com doses crescentes de GYY4137 (0,3 30 nmol/sitio, i.d.) inibiu o prurido agudo induzido por histamina ou cloroquina e reduziu o influxo de neutrófilos frente ao C48/80, mas não afetou o extravasamento plasmático induzido por histamina ou C48/80. O bloqueio das enzimas geradoras de H2S maximizou o prurido e o influxo de neutrófilos desencadeado por C48/80. O pré-tratamento com a glibenclamida (10 mg/kg; i.p, -30 min), bloqueador dos canais de KATP, não reverteu o efeito do doador de H2S de liberação rápida sobre o prurido agudo e inflamação induzidos por histamina. Em animais com psoríase, o tratamento (i.p.) com o GYY4137 reduziu (P<0,05) a inflamação cutânea (escores PASI) e o prurido, assim como inibiu o eixo NF-<font face = \"symbol\">k B-caspase-1-IL-1<font face = \"symbol\">b , e aumentou a atividade das enzimas antioxidantes (catalase, GST, GR e GPx). A pele de animais com psoríase exibiu menor capacidade na síntese de H2S, que foi paralela à menor expressão da enzima Cistationina-<font face = \"symbol\">b-sintetase (CBS). O bloqueador da enzima Cistationina-<font face = \"symbol\">g-liase (CSE) não interferiu no escore PASI ou prurido. Conclui-se que moléculas doadoras de H2S representam novos alvos terapêuticos no controle da inflamação aguda ou imunomediada associada à percepção de prurido agudo ou crônico. No microambiente inflamatório agudo, o mecanismo envolvido é independente da ativação de canais de KATP, enquanto no crônico (psoríase) é dependente, em parte, da inibição da ativação do eixo NF-<font face = \"symbol\">k B- caspase-1-IL-1<font face = \"symbol\">b e aumento das defesas antioxidantes. / Pruritus, like pain, is an aversive sensory experience associated with the scratching desire. Previous findings from this group demonstrated that hydrogen sulphide (H2S) donor molecules, a new endogenous mediator, when intra-dermal injected, reduced acute histamine and cutaneous inflammation induced by histamine or compound 48/80 (C48/80) on the dorsal skin of mice, suggesting the involvement of H2S in the control of amine-mediated pruritus. However, little is known about the mechanisms involved in the induction or inhibition of this sensorial perception (acute or chronic) and the participation of H2S. In order to get a better understanding, the objectives of this study were: i) to test and characterize the mechanisms involved in the protective effects of different H2S donors molecules (fast and slow release) on acute pruritus and associated inflammation induced by histamine dependent and independent stimuli; ii) to investigate the endogenous production of H2S and the enzymes involved in its synthesis in healthy and unhealthy/disease murine skin; and iii) to standardize a model of chronic pruritus associated with the psoriasis area severity index (PASI) in the inflamed skin, and to investigate the protective effect of a slow release H2S donor (GYY4137). The behaviour evaluation of acute pruritus and cutaneous inflammation (plasma extravasation, neutrophil influx) was performed alongside with different stimuli with or without the co-treatment (i.d.) with H2S donors in Balb/C mice. Experimental psoriasis was induced by topical application of imiquimod cream (IMQ 5%) on the dorsal skin, for 5 consecutive days, and at the same time, groups with the disease were treated intraperitoneally (i.p.) with GYY4137 at different doses (25 100 mg/kg). Records of pruritus and PASI were obtained during psoriasis induction, and biochemical and molecular analyses were performed at the end of the experiment. Firstly, treatment with increasing doses of GYY4137 (0.3 30 nmol/site, i.d.) inhibited acute pruritus induced by histamine or chloroquine and reduced the neutrophils influx induced by C48/80, without affecting histamine or C48/80 plasma-induced extravasation. Secondly, blocking the H2S-generating enzymes potentiated pruritus and the neutrophils influx triggered by C48/80. Pretreatment with glibenclamide (10 mg/kg; i.p., -30 min.), a KATP channel blocker, did not reverse the effect of the fast-release H2S donor on acute pruritus and inflammation induced by histamine. Finally, psoriatic animals, treated with GYY4137 (i.p.) showed a lower skin inflammation (PASI scores) and pruritus as well as the NF<font face = \"symbol\">kB-Caspase1-IL-1<font face = \"symbol\">b axis inhibited (P>0.05), and increased activity of antioxidant enzymes (catalase, GST, GR and GPx). The skin of psoriatic animals exhibited a lower capacity to synthetize H2S, which was parallel to expression of the enzyme Cystathionine-<font face = \"symbol\">b-synthetase (CBS). The Cystathionine-<font face = \"symbol\">g-lyase (CSE) enzyme blocker did not interfere with the PASI or pruritus score. We may conclude that H2S donor molecules represent new therapeutic targets to the control of acute or immune- mediated inflammation associated with the perception of acute or chronic pruritus. Also, in the acute inflammatory microenvironment, the mechanism involved is independent of KATP channels activation, whereas in the chronic condition it is partly dependent on the inhibition of NF-<font face = \"symbol\">kB-caspase-1-IL-1<font face = \"symbol\">b axis activation and increased antioxidants defence.

Made available in DSpace on 2014-12-17T15:42:26Z (GMT). No. of bitstreams: 1 ValdeliceRS.pdf: 981957 bytes, checksum: cedb4f2ae440069c889ba97e29744a20 (MD5) Previous issue date: 2007-07-11 / The natural gas (NG) is a clean energy source and found in the underground of porous rocks, associated or not to oil. Its basic composition includes methane, ethane, propane and other components, like carbon dioxide, nitrogen, hydrogen sulphide and water. H2S is one of the natural pollutants of the natural gas. It is considered critical concerning corrosion. Its presence depends on origin, as well as of the process used in the gas treatment. It can cause problems in the tubing materials and final applications of the NG. The Ag?ncia Nacional do Petr?leo sets out that the maximum concentration of H2S in the natural gas, originally national or imported, commercialized in Brazil must contain 10 -15 mg/cm3. In the Processing Units of Natural Gas, there are used different methods in the removal of H2S, for instance, adsorption towers filled with activated coal, zeolites and sulfatreat (solid, dry, granular and based on iron oxide). In this work, ion exchange resins were used as adsorbing materials. The resins were characterized by thermo gravimetric analysis, infrared spectroscopy and sweeping electronic microscopy. The adsorption tests were performed in a system linked to a gas-powered chromatograph. The present H2S in the exit of this system was monitored by a photometrical detector of pulsing flame. The electronic microscopy analyzes showed that the topography and morphology of the resins favor the adsorption process. Some characteristics were found such as, macro behavior, particles of variable sizes, spherical geometries, without the visualization of any pores in the surface. The infrared specters presented the main frequencies of vibration associated to the functional group of the amines and polymeric matrixes. When the resins are compared with sulfatreat, under the same experimental conditions, they showed a similar performance in retention times and adsorption capacities, making them competitive ones for the desulphurization process of the natural gas / O g?s natural (GN) ? uma fonte de energia limpa encontrada no subsolo de rochas porosas, associado ou n?o ao petr?leo. Sua composi??o b?sica inclui metano, etano, propano e outros componentes, como di?xido de carbono, nitrog?nio, ?cido sulf?drico e ?gua. H2S ? um dos poluentes naturais do g?s natural. ? considerado cr?tico no que se refere ? corros?o. Sua presen?a depende da origem, bem como do processo usado no tratamento do g?s. Ele pode acarretar problemas nas tubula??es e aplica??es finais do GN. A Ag?ncia Nacional de Petr?leo estabelece que a concentra??o m?xima de H2S no g?s natural, de origem nacional ou importado, comercializado no Brasil contenha no m?ximo 10 15 mg/m3. Nas Unidades de Processamento do G?s Natutal, diferentes m?todos s?o usados na remo??o de H2S, por exemplo, em torres de adsor??o recheadas com carv?o ativo, ze?litas e Sulfatreat (s?lido, seco, granular e baseado em ?xido de ferro). Neste trabalho, resinas de troca-i?nica foram usadas como material adsorvente. As resinas foram caracterizadas por an?lise termogravim?trica, espectroscopia de infravermelho e microscopia eletr?nica de varredura. Os ensaios de adsor??o foram realizados em um sistema acoplado a um cromat?grafo a g?s. O H2S presente na sa?da do sistema foi monitorado por um detector fotom?trico de chama pulsante. As an?lises de microscopia eletr?nica demonstraram que a topografia e morfologia das resinas favorecem o processo de adsor??o. Caracter?sticas como comportamento macro, part?culas de tamanhos variados, geometrias esf?ricas, sem a visualiza??o de poros na superf?cie, foram encontrados. Os espectros de infravermelho apresentaram as principais freq??ncias de vibra??o associadas aos grupos funcionais das aminas e matrizes polim?ricas. Quando comparadas ao sulfatreat, sob as mesmas condi??es experimentais, as resinas demonstraram semelhante desempenho em tempos de reten??o e capacidade de adsor??o, tornando-se competitiva para o processo de dessulfuriza??o do g?s natural

Made available in DSpace on 2014-12-17T15:42:27Z (GMT). No. of bitstreams: 1 ValdeliceRS.pdf: 629576 bytes, checksum: 6bcf4a0b805ce82618289068cfb23b77 (MD5) Previous issue date: 2006-07-11 / The natural gas (NG) is a clean energy source and found in the underground of porous rocks, associated or not to oil. Its basic composition includes methane, ethane, propane and other components, like carbon dioxide, nitrogen, hydrogen sulphide and water. H2S is one of the natural pollutants of the natural gas. It is considered critical concerning corrosion. Its presence depends on origin, as well as of the process used in the gas treatment. It can cause problems in the tubing materials and final applications of the NG. The Ag?ncia Nacional do Petr?leo sets out that the maximum concentration of H2S in the natural gas, originally national or imported, commercialized in Brazil must contain 10 -15 mg/cm3. In the Processing Units of Natural Gas, there are used different methods in the removal of H2S, for instance, adsorption towers filled with activated coal, zeolites and sulfatreat (solid, dry, granular and based on iron oxide). In this work, ion exchange resins were used as adsorbing materials. The resins were characterized by thermo gravimetric analysis, infrared spectroscopy and sweeping electronic microscopy. The adsorption tests were performed in a system linked to a gas-powered chromatograph. The present H2S in the exit of this system was monitored by a photometrical detector of pulsing flame. The electronic microscopy analyzes showed that the topography and morphology of the resins favor the adsorption process. Some characteristics were found such as, macro behavior, particles of variable sizes, spherical geometries, without the visualization of any pores in the surface. The infrared specters presented the main frequencies of vibration associated to the functional group of the amines and polymeric matrixes. When the resins are compared with sulfatreat, under the same experimental conditions, they showed a similar performance in retention times and adsorption capacities, making them competitive ones for the desulphurization process of the natural gas / O g?s natural (GN) ? uma fonte de energia limpa encontrada no subsolo de rochas porosas, associado ou n?o ao petr?leo. Sua composi??o b?sica inclui metano, etano, propano e outros componentes, como di?xido de carbono, nitrog?nio, ?cido sulf?drico e ?gua. H2S ? um dos poluentes naturais do g?s natural. ? considerado cr?tico no que se refere ? corros?o. Sua presen?a depende da origem, bem como do processo usado no tratamento do g?s. Ele pode acarretar problemas nas tubula??es e aplica??es finais do GN. A Ag?ncia Nacional de Petr?leo estabelece que a concentra??o m?xima de H2S no g?s natural, de origem nacional ou importado, comercializado no Brasil contenha no m?ximo 10 15 mg/m3. Nas Unidades de Processamento do G?s Natutal, diferentes m?todos s?o usados na remo??o de H2S, por exemplo, em torres de adsor??o recheadas com carv?o ativo, ze?litas e Sulfatreat (s?lido, seco, granular e baseado em ?xido de ferro). Neste trabalho, resinas de troca-i?nica foram usadas como material adsorvente. As resinas foram caracterizadas por an?lise termogravim?trica, espectroscopia de infravermelho e microscopia eletr?nica de varredura. Os ensaios de adsor??o foram realizados em um sistema acoplado a um cromat?grafo a g?s. O H2S presente na sa?da do sistema foi monitorado por um detector fotom?trico de chama pulsante. As an?lises de microscopia eletr?nica demonstraram que a topografia e morfologia das resinas favorecem o processo de adsor??o. Caracter?sticas como comportamento macro, part?culas de tamanhos variados, geometrias esf?ricas, sem a visualiza??o de poros na superf?cie, foram encontrados. Os espectros de infravermelho apresentaram as principais freq??ncias de vibra??o associadas aos grupos funcionais das aminas e matrizes polim?ricas. Quando comparadas ao sulfatreat, sob as mesmas condi??es experimentais, as resinas demonstraram semelhante desempenho em tempos de reten??o e capacidade de adsor??o, tornando-se competitiva para o processo de dessulfuriza??o do g?s natural

S’ha estudiat la formació de sulfur d’hidrogen (H2S) i altres compostos de sofre volàtils lleugers com els mercaptans i disulfurs per part dels llevats durant la fermentació vínica. Es proposen mètodes per mesurar i evitar el problema de l’olor desagradable del H2S i els seus derivats, des de la vinya, el most, els llevats i el vi, i respectar les aromes pròpies de cada varietat. S’han analitzat diferents factors de la producció dels compostos de sofre, la descripció dels defectes associats, la formació dels sulfurs: anàlisi, identificació i quantificació dels sulfurs en vins, s’han identificat compostos com l’etil mercaptà, sulfur de dimetil i en menor quantitat el sulfur de dietil i el sulfur de metil. S’ha estudiat el moment de la formació en mostos model, i s’ha vist una o dues fases durant la fermentació on la producció de sulfur és alta. S’han estudiat les aromes típiques de varietats locals mitjançant l’anàlisi sensorial descriptiva. En un estudi de soques de llevat, s’ha observat que la majoria (60%) produeixen alguna quantitat de sulfurs durant la fermentació i que l’elecció de la soca és un factor important. S’han provat tres tipus de reg en vinya i s’ha vist que influeix en els estils dels vins i en els compostos nitrogenats dels mostos resultants. En vinya per la prevenció de l’oïdi es van fer tractaments alternatius sense sofre, per tal d’evitar la formació de sulfurs. Per a identificar el component genètic de la producció de H2S s’han comparat els transcriptomes de dues soques amb propietats enològiquessimilars, però diferent producció de H2S: UCD 522 (alta producció) i P29 (baixa producció). Les mostres es van extreure durant fermentacions en el moment de màxima producció de H2S. Degut a què no eren soques de laboratori es van fer tres tipus d’estudi del perfil de transcripció de les dues soques de llevat: un array basat en el cADN, un array basat en oligonucleòtids i un anàlisi per qRTPCR d’una selecció de transcripts. Els resultats foren similars amb les tres tècniques. Més del 90% dels gens no van mostrar diferències entre les dues soques. En canvi, la majoria dels gens relacionats amb la biosíntesi de la tiamina van tenir una sobreexpressió a la soca amb alta producció de H2S. Per contra, gens relacionats amb el catabolisme dels aminoàcids, una possible font de H2S, no van mostrar diferències d’expressió entre les dues soques. Això suggereix que, en les condicions estudiades, el metabolisme secundari com la biosíntesi de la tiamina i altres compostos amb sofre pot ser clau per explicar la producció de H2S per algunes soques de llevat durant la fermentació. En vins amb defectes de compostos de sofre volàtil s’han tractat amb citrat de coure i s’ha vist que podia ser una alternativa al sulfat de coure que s’ha fet servir tradicionalment.

Macroscopical and microscopical observations on extant and fossil plants have been made. Observations on extant plants led to study the effects of volcanic gases on the cuticle ultrastructure of Pinus halepensis and Erica arborea sampled in the volcanic area of Phlegrean Italy. TEM observations on P. halepensis cuticles fumigated or not by volcanic gases revealed: 1) insignificant thickness variations of the cell wall plus cuticle among current- and first-year-old needles of both fumigated and not fumigated trees; 2) a calcium oxalate accumulation in fumigated leaves; 3) moreover, in respect to the cell surface, fibrils are disposed parallel to the surface of the cuticle. In specimens of E. arborea fumigated or not by volcanic gases, 1) the total thickness of cuticles varies significantly; 2) in plants experiencing chronic fumigation the A2 layer increases its thickness. As for fossil plants, the cuticles of Cretaceous Fossil-Lagertätten of Cusano Mutri and Pietraroja have been studied. In the former: 1) numerous taxa belonging to conifers have been identified; 2) the new species Frenelopsis cusanensis has been described; 3) Montsechia vidalii has been found outside of Spain. Taxonomical studies allowed the description of typical Euro-Sinian fossil plants. Sedimentological and taxonomical studies suggest semi-arid or arid conditions in a subtropical or tropical climate. It is worth noting as for Cusano Mutri locality, evidence of wildfire (fusain) suggests a periodic combination of arid periods, high temperatures and lightning strikes.