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1
Fismes-Bemer, Joëlle. "Effet de la fertilisation azotée et soufrée et d'un inhibiteur de nitrification (ATS) sur la nutrition azotée et soufrée du colza". Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPL062N.
Testo completoAbstract (sommario):
Le colza est une plante exigeante en azote pour son développement et la production de graines. C’est en outre une plante particulièrement sensible aux carences en soufre car elle utilise le soufre dans de nombreuses réactions métaboliques mais aussi pour la synthèse d'acides aminés soufrés. Cependant, la fertilisation azotée et soufrée du colza doit être raisonnée afin d'augmenter productivité et qualité tout en limitant les pertes d'éléments fertilisants qui occasionnent surcoût et pollution. Le sol argilo-calcaire de lorraine étudié est riche en azote et en soufre totaux, principalement immobilisés dans les fractions fines. Ce sol est cependant peu favorable à la minéralisation de l'azote et du soufre organiques. Par contre, la nitrification de l'ammonium y est très rapide, d'où des pertes non négligeables d'azote par dénitrification et lessivage des nitrates, et l'intérêt porte aux inhibiteurs de nitrification et d'uréase. L’azote et le soufre apportés sont de plus rapidement immobilisés dans le sol par les micro-organismes. Cependant, cette faible disponibilité des engrais est compensée par un effet stimulant de la fertilisation sur la minéralisation de l'azote et du soufre natifs du sol. L’azote et le soufre étant indissociables dans les mécanismes de synthèse des acides aminés et des protéines, nous avons aussi mis en évidence l'influence réciproque de ces 2 éléments sur leur prélèvement respectif par le colza, leur distribution et leur assimilation dans la plante. Ainsi, un déséquilibre entre l'azote assimilable et le soufre assimilable a des répercussions sur la production des graines et leur qualité. En tant qu'inhibiteur de nitrification et d'uréase, l'ATS s'est révélé peu efficace en sol argilo-calcaire en raison des propriétés physiques, chimiques et biologiques de ce sol. Il agit en effet sur la dynamique de l'azote du sol seulement à des doses élevées et pendant une période courte (4 semaines). Quant à son impact sur le prélèvement d'azote par les plantes, il est dû essentiellement à sa composition soufrée.
2
Uddin, Md Miar. "The impact of maleic hydrazide, nitrogen and sulphur nutrition on the postharvest quality of onion (Allium cepa L.) during storage". Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408023.
Testo completo
3
Bonnot, Titouan. "Réponse du grain de blé à la nutrition azotée et soufrée : étude intégrative des mécanismes moléculaires mis en jeu au cours du développement du grain par des analyses -omiques". Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22767/document.
Testo completoAbstract (sommario):
L’augmentation des rendements est un enjeu majeur chez les céréales. Dans cet objectif, il est nécessaire de maintenir la qualité du grain de blé, qui est principalement déterminée par sa teneur et sa composition en protéines de réserve. En effet, une forte relation négative existe entre le rendement et la teneur en protéines. Par ailleurs, la qualité du grain est fortement influencée par la disponibilité en azote et en soufre dans le sol. La limitation des apports d’intrants azotés à la culture et la carence en soufre récemment observée dans les sols représentent ainsi des difficultés supplémentaires pour maitriser cette qualité. Une meilleure connaissance des mécanismes moléculaires impliqués dans le contrôle du développement du grain et la mise en place de ses réserves protéiques en réponse à la nutrition azotée et soufrée est donc primordiale. L’objectif de cette thèse a ainsi été d’apporter de nouveaux éléments à la compréhension de ces processus de régulation, aujourd’hui peu connus. Pour cela, les approches -omiques sont apparues comme une stratégie de choix pour identifier les acteurs moléculaires mis en jeu. Le protéome nucléaire a été une cible importante dans les travaux menés. L’étude de ces protéines nucléaires a révélé certains régulateurs transcriptionnels qui pourraient être impliqués dans le contrôle de la mise en place des réserves du grain. Dans une approche combinant des données de protéomique, transcriptomique et métabolomique, une vision intégrative de la réponse du grain à la nutrition azotée et soufrée a été obtenue. L’importance d’un apport de soufre dans le contrôle de la balance azote/soufre du grain, déterminante pour la composition du grain en protéines de réserve, a été clairement vérifiée. Parmi les changements observés au niveau du métabolisme cellulaire, certains des gènes affectés par la modification de cette balance pourraient orchestrer l’ajustement de la composition du grain face à des situations de carences nutritionnelles. Ces nouvelles connaissances devraient permettre de mieux maitriser la qualité du grain de blé dans un contexte d’agriculture durableImproving the yield potential of cereals represents a major challenge. In this context, wheat grain quality has to be maintained. Indeed, grain quality is mainly determined by the content and the composition of storage proteins, but there is a strongly negative correlation between yield and grain protein concentration. In addition, grain quality is strongly influenced by the availability of nitrogen and sulfur in soils. Nowadays, the limitation of nitrogen inputs, and also the sulfur deficiency recently observed in soils represent major difficulties to control the quality. Therefore, understanding of molecular mechanisms controlling grain development and accumulation of storage proteins in response to nitrogen and sulfur supply is a major issue. The objective of this thesis was to create knowledge on the comprehension of these regulatory mechanisms. For this purpose, the best strategy to identify molecular actors involved in these processes consisted of -omics approaches. In our studies, the nuclear proteome was an important target. Among these proteins, we revealed some transcriptional regulators likely to be involved in the control of the accumulation of grain storage compounds. Using an approach combining proteomic, transcriptomic and metabolomic data, the characterization of the integrative grain response to the nitrogen and sulfur supply was obtained. Besides, our studies clearly confirmed the major influence of sulfur in the control of the nitrogen/sulfur balance that determines the grain storage protein composition. Among the changes observed in the cell metabolism, some genes were disturbed by the modification of this balance. Thus these genes could coordinate the adjustment of grain composition in response to nutritional deficiencies. These new results contribute in facing the challenge of maintaining wheat grain quality with sustainable agriculture
4
Daraja, Yusuf B. "The effects of intercropping, nitrogen and sulphur nutrition on the performance of wheat (Triticum aestivum) and Faba Bean (Vicia faba) in different production systems". Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515808.
Testo completo
5
Coquerel, Raphael. "Etude d'un appοrt en silicium sur le métabοlisme azοté et les perfοrmances agrοnοmiques du cοlza (Brasscia napus L.) et du trèfle (Τrifοllium incarnatum L.) cultivés en mοnοculture et en assοciatiοn". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMC246.
Testo completoAbstract (sommario):
Chaque année, plus de 3,7 millions de tonnes d'engrais azotés sont utilisées par l'agriculture française. Bien qu'étant un élément essentiel au bon développement et à la bonne croissance des plantes, la fertilisation azotée est de plus en plus décriée en raison des nombreuses nuisances aux écosystèmes et à la biodiversité qu'il induit. Le colza (Brassica napus L.) est l'une des plantes de grandes cultures les plus exigeantes en azote (N), en raison de sa faible efficience d'usage de cet élément. Dans le but de maintenir une croissance et des rendements optimaux de la culture de colza tout en limitant les apports en fertilisants azotés, il est essentiel de mettre au point de nouvelles pratiques culturales plus respectueuses de l'environnement. Dans ce contexte, l'utilisation combinée des cultures associées à base de Fabacées et de produits biostimulants constitue une alternative intéressante aux pratiques actuelles de la culture de colza. Du fait de ses nombreux effets bénéfiques lors de stress biotiques et abiotiques, le silicium (Si) semble être un biostimulant pertinent. Les objectifs de ces travaux de thèse visent à observer les effets d'un apport en Si sur (i) les performances agronomiques du colza et du trèfle en monoculture cultivés en conditions contrôlées et (ii) sur une possible potentialisation du fonctionnement de l'association colza-trèfle incarnat. Dans un premier temps, nos travaux ont permis de montrer qu'en condition de carence en soufre (S), un apport de Si s'accompagne d'une baisse du stress oxydatif et d'une modulation de l'expression des gènes codant les transporteurs racinaires de sulfate qui permet aux plantes traitées au Si d'être plus efficaces pour absorber le S lorsque celui-ci est à nouveau disponible. Dans un second temps, l'apport de Si à une culture de trèfle incarnat soumis à une carence en S ou cultivé avec une solution nutritive dépourvue d'N a un impact positif sur la nodulation et les capacités de fixation du diazote atmosphérique. Le Si induit une augmentation significative du nombre de nodules racinaires ainsi que de leur teneur en nitrogénase. En outre, l'étude du ionome et du protéome des nodules a permis de mieux comprendre les effets d'un apport en Si en montrant notamment l'accumulation d'éléments et de protéines impliqués directement ou indirectement dans la fixation de diazote atmosphérique. Enfin, nos travaux ont mis en lumière les effets bénéfiques d'un apport en Si sur une association colza-trèfle notamment en augmentant le transfert d'N de la Fabacée vers la Brassicacée et en améliorant le rendement grainier du colzaOver 3.7 million tonnes of N fertilizers are used in French agriculture every year. Although N fertilization is an essential element for the growth of crops, it is increasingly criticized for its harmful effects on ecosystems and biodiversity. rapeseed (Brassica napus L.) is one of the most N requiring field crops, due to its low N use efficiency. To maintain optimum the growth and the yield of rapeseed with lower N fertilizer inputs, it is crucial to develop new cultural practices more respectful of environment. In this context, the combination of rapeseed-clover intercrops and biostimulants is an interesting alternative to the current cultivation practices of rapeseed. Considering its numerous beneficial effects under biotic and abiotic stresses, Silicon (Si) appears to be a relevant biostimulant. The aim of this PhD work was to observe the effects of Si supply on (i) the agronomic performance of monoculture rapeseed and clover grown under controlled conditions, and (ii) the possible potentiation of the functioning of the rapeseed-clover intercrop. Firstly, our work has shown that under sulfur (S) deficiency conditions, the supply of Si leads to a reduction in oxidative stress and modulation of the expression of genes encoding root sulfate transporters, allowing +Si plants to take up S more efficiently when it becomes available again. Secondly, the Si supply to crimson clover subjected under S-deficiency or or grown without N in the nutrient solution, had a positive impact on nodulation and atmospheric dinitrogen fixation capacities. Si induces a significant increase in the number of root nodules and their nitrogenase content. In addition, the study of the nodule ionome and proteome has enhanced our knowledge of the benefit effects of Si supply, particularly by showing the accumulation of elements and proteins directly or indirectly involved in the fixation of atmospheric dinitrogen. Finally, our work has highlighted the beneficial effects of Si supply on a rapeseed-clover intercrop, notably by increasing the N transfer from the Fabaceae to the Brassicaceae and improving the yield of the rapeseed
6
Oliveira, Robinson Jardel Pires de. "Adubação para a cultura da beterraba (Beta vulgaris L.) na região do Alto Vale do Itajaí". Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/602.
Testo completoAbstract (sommario):
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Previous issue date: 2015-03-13The recommendation of fertilizer for beet cultivation in Santa Catarina still lacks adjustments and, therefore, this study was conducted to evaluate the crop response to fertilization with nitrogen (N), phosphorus (P), potassium (K), sulfur (S), boron (B), zinc (Zn) and molybdenum (Mo). Three experiments were conducted on the field and one at greenhouse in the IFC, Rio do Sul (SC), using a Cambisol. In the first study, it was used the randomized block design in a factorial 4 x 4 with three replications, in which it were tested P (0, 200, 400 and 600 kg ha-1 of P2O5) and K rates (0, 150, 300 and 450 kg ha-1 K2O). On the second crop it was evaluated the replacement rates of 0, 33% and 66% of the initial doses. In both cases, the seedlings were transplanted and harvested 60 days after transplantation. It was determined the root diameter and the fresh and dry weight of leaves and roots, and the P and K content in the plant tissue. In the first crop beet reached maximum yield with 379 kg ha-1 P2O5 and it has not been observed response to K. On the second crop the maximum yield was obtained with the highest levels of P and K of applies on the first crop plus the largest replacement rate. In experiment 2, conducted in a 5x2 factorial arrangement in randomized blocks design with four replications, it were tested N rates (0, 50, 100, 150 and 200 kg ha-1) in the presence or absence of fertilization with S, Zn, B, Mo (rates of 30, 2, 1 and 0.01 kg ha-1 respectively). The beet responded positively to N rates up to 100 kg ha-1, increasing production when other nutrients were applied. Based on these results, the experiment 3 was installed in a greenhouse in order to determine which of the nutrients from experiment 2 was responsive. The treatments were: B, Zn, S e Mo, complete (B + Zn + S + Mo) and control, arranged in a completely randomized design with four replications. The results showed that the responsive nutrient was S. From this result, it was installed the field experiment 4 in a randomized block design with four replications testing S rates (0, 30, 60, 90, 120 and 150 kg ha-1). The beet answered positively to fertilization with S up to 60 kg ha-1
A recomendação de fertilizantes para a cultura da beterraba no âmbito de Santa Catarina ainda carece de ajustes e, por isso, este trabalho foi conduzido com o objetivo avaliar a resposta da cultura da beterraba à adubação com nitrogênio (N), fósforo (P), potássio (K), enxofre (S), boro (B), zinco (Zn) e molibdênio (Mo). Foram conduzidos três experimentos à campo e um em casa-de-vegetação no IFC, em Rio do Sul (SC), sob solo Cambissolo Háplico. O experimento 1 foi conduzido em dois cultivos. No primeiro cultivo utilizou-se o delineamento blocos ao acaso em esquema fatorial 4 x 4 com três repetições, nas quais foram testadas as doses de P (0, 200, 400 e 600 kg ha-1 de P2O5) e K (0, 150, 300 e 450 kg ha-1 de K2O). No segundo cultivo avaliaram-se as doses de reposição de 0, 33% e 66% das doses iniciais. Em ambos, foram transplantadas as mudas no espaçamento de 0,25 x 0,08 m e a colheita foi efetuada 60 dias após o transplante. Determinaram-se o diâmetro de raiz e a massa fresca e seca de folhas e raízes, o teor de P e K no tecido vegetal. No primeiro cultivo, a beterraba aumentou a produtividade com a aplicação de até 379 kg ha-1 de P2O5, não tendo sido observada resposta ao K. No segundo cultivo a máxima produtividade foi obtida nas parcelas com as maiores doses de P e K do primeiro cultivo, acrescidas da maior dose de reposição. No experimento 2, conduzido no esquema fatorial 5x2, no delineamento blocos ao acaso com quatro repetições, foram testadas as doses de N (0, 50, 100, 150 e 200 kg ha-1) na presença ou ausência de adubação conjunta com S, Zn, B e Mo (doses de 30, 2, 1 e 0,01 kg ha-1, respectivamente). A beterraba respondeu positivamente à aplicação de doses de N até 100 kg ha-1, acrescida da adubação com os demais nutrientes. Com base nestes resultados, foi instalado o experimento 3, em casa-de-vegetação, com o objetivo de determinar qual dos nutrientes do experimento 2 foi responsável pela resposta. Os tratamentos foram: B, Zn S, Mo, completo (B+Zn+S+Mo) e testemunha, arranjados em delineamento inteiramente casualizado com quatro repetições. Os resultados evidenciaram que o nutriente determinante na produtividade foi o S. A partir desses resultados, instalou-se a campo o experimento 4 no delineamento em blocos ao acaso com quatro repetições testando as doses de S (0, 30, 60, 90, 120 e 150 kg ha-1). A beterraba respondeu positivamente à adubação com S até a dose de 60 kg ha-1
7
Matuska, Vit. "Five-membered sulfur-nitrogen ring compounds". Thesis, St Andrews, 2009. http://hdl.handle.net/10023/828.
Testo completo
8
Allertz, Carl. "Sulfur and nitrogen in ladle slag". Doctoral thesis, KTH, Mikro-modellering, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-182981.
Testo completoAbstract (sommario):
The present work deals with some aspects of slags related to secondary metallurgy in the steelmaking process. More specifically the focus is given to sulfur and nitrogen in ladle slags. Even though slags have been fairly well-researched in the past, the available data for these elements in typical ladle slag compositions is rather scarce. In some cases the available data is in discordance. There are also inconsistencies between the literature data and what is commonly observed in the industrial processes. Sulfide capacities were measured at steelmaking temperatures, 1823–1873 K, in ladle slags. The data was found to be in reasonable agreement with the industrial process norms. The sulfide capacity was found to increase with the basic oxides CaO and MgO; and decrease with the acidic components Al2O3 and SiO2. The sulfide capacity was also found to increase with temperature. The dependence of sulfide capacity on the oxygen partial pressure, for slags containing multivalent elements, was investigated experimentally at 1873 K with a slag containing vanadium oxide. A strong dependence of oxygen partial pressure was observed. The sulfide capacity increase by more than two orders of magnitude when the oxygen partial pressure was increased from 4.6×10-16 atm to 9.7×10-10 atm. The nitrogen solubility and the effect of carbon was investigated in typical ladle slags and the CaO–MgO–SiO2 system at 1873 K. Carbon increases the nitrogen solubility substantially. In the absence of carbon, the nitrogen solubility is extremely low. Low concentrations of cyanide was detected in the carbon saturated slag. This was much lower than the total nitrogen content and formation of cyanide cannot explain the large increase. The possibility of removing sulfur with oxidation from used ladle slag was investigated experimentally at 1373–1673 K. The sulfur removal of mostly solid slag was found to be a slow process, and would not suitable for industrial practice. At 1673 K the slag was mostly liquid and more than 85% of the sulfur was removed after 60 min of oxidation in pure oxygen atmosphere.QC 20160229
9
Preuss, Kathryn Elvia. "Sulfur nitrogen heterocycles as charge transfer materials". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0018/NQ53510.pdf.
Testo completo
10
Cigelske, Benjamin. "Soybean Response to Nitrogen and Sulfur Fertilization". Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28249.
Testo completoAbstract (sommario):
Soybean [Glycine max (L.) Merrill.] yields in North Dakota have not yet reached their genetic potential. Applying fertilizers may increase yields. This study was conducted to understand the impact of nitrogen (N) and sulfur (S) fertilization on soybean plant density, vigor, greenness, height, yield, test weight, protein and oil content, nodulation, vegetation, and root growth. Two varieties were planted in experiments across ten environments during 2015-2016. Yield differed between environments (up to 77%). Varieties responded differently to N and S fertilizer. Nitrogen (56 kg N ha-1) in the form of broadcast incorporated urea increased vigor (13%) and yield (3.6%) but decreased plant density (5.7%) and nodulation (from 31.8 to 23.7 nodules plant-1). Nitrogen application of 56 kg N ha-1 increased yield 118 kg ha-1 when averaged over all environments. Sulfur, in the form of broadcast incorporated gypsum, decreased protein concentration and increased early season nodule size.North Dakota Soybean Council
11
James, Daniel Stuart. "Novel nitrogen-sulfur chelate ligands for asymmetric catalysis". Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287727.
Testo completo
12
Hargreaves, Stephen. "Novel supramolecular assemblies based on sulfur-nitrogen radicals". Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19755/.
Testo completoAbstract (sommario):
This thesis describes the synthesis of a range of novel dithiadiazolyl radicals. The structures of these compounds are discussed. The physical properties of several compounds have been investigated using EPR spectroscopy and magnetic susceptibility studies. Chapter one begins with an overview of the chemistry of 1,2,3,5-dithiadiazolyl radicals. A general discussion of the history of organic conductors and magnets, and the terms involved in some of the techniques used is given in order to provide a background to the work presented. The second chapter outlines the synthesis and general characterisation of all the dithiadiazolyl radicals discussed in this thesis. A proposed mechanism for the conversion of parent nitriles into dithiadiazolyl radicals has been included. The third chapter describes the solid state structures of three dichlorophenyl dithiadiazolyl derivatives (2,4-, 2,5- and 3,5-dichlorophenyl-l,2,3,5-dithiadiazolyl). A further polymorph of 3,5-dichlorophenyl-1,2,3,5-dithiadiazolyl has also been included. The magnetic susceptibility of 2,4- and 3,5-dichlorophenyl-1,2,3,5-dithiadiazolyl has been investigated and the EPR analysis of all three compounds has been performed. These compounds are the first examples of neutral dithiadiazolyl radicals that form evenly spaced, segregated stacks in the solid state. Chapter four describes the dimer stacking structures of two further dichlorophenyl dithiadiazolyl derivatives (2,3- and 3,4-dichlorophenyl-1,2,3,5-dithiadiazolyl). The fifth chapter discusses the association of 3,5-dibromphenyl-1,2,3,5-dithiadiazolyl in the solid state. An investigation of this compound by EPR spectroscopy is also presented. Chapter six describes the trans cofacial association of p-iodophenyl-1,2,3,5-dithiadiazolyl in the solid state, only the second published example of this mode of dimerisation. The synthesis of o- and p-iodobenzonitrile are also described. An investigation of the EPR signal of this compound has also been included. Chapter seven describes the specialised techniques used in the synthesis of all the compounds. A list of the instruments used for analysis is also included.
13
Zhao, Shan. "Nitrogen nutrition of hybrid poplars". Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/summer2006/S%5FZhao%5F072906.pdf.
Testo completo
14
Wilkinson, Nikki. "Nitrogen nutrition in marine Synechococcus". Thesis, University of Reading, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494972.
Testo completoAbstract (sommario):
Marine Synechococcus spp. are ubiquitous in the marine environment and are known to contribute significantly to primary production. The ecological success of these organisms may be due to the evolution of various genetic lineages physiologically adapted to specific ocean niches. This study focused on one specific physiological attribute, the utilisation and genetic regulation of nitrogen (N) nutrition. Growth data showed no discernable difference in N source utilisation capabilities between marine Synechococcus lineages, but rather a broad utilisation of a range of N sources including ammonium, nitrate, nitrite, urea, and some amino acids. The specific inability of individual strains to utilise urea or nitrate correlated with a lack of genetic capacity to acquire and metabolise these substrates. Such gene loss is likely a function then, of very local environmental conditions 'acting on' a specific strain, rather than a much broader environmental influence on the lineage as a whole.
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Sun, Chaode. "Syntheses and reactivities of [pi]-electron rich phosphorus-nitrogen and sulfur-nitrogen ligands". HKBU Institutional Repository, 1999. http://repository.hkbu.edu.hk/etd_ra/140.
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Bona, Fabiano Daniel De. "Nitrogênio e enxofre para gramínea forrageira: atributos do solo e aspectos metabólicos, nutricionais e produtivos da planta". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-10032009-091221/.
Testo completoAbstract (sommario):
A disponibilidade dos nutrientes nitrogênio e enxofre no solo pode alterar o desenvolvimento das plantas com reflexos diretos na produção vegetal. Objetivou-se: a) estudar doses de nitrogênio e doses de enxofre na produção da Brachiaria brizantha cv. Marandu (capim-Marandu) em implantação em solo de pastagem com Brachiaria decumbens (capim-Braquiária) em degradação, e avaliar as alterações nas concentrações desses elementos no tecido vegetal e no solo promovidas por essa adubação; b) avaliar a eficiência do uso da água pelo capim-Marandu em estabelecimento adubado com nitrogênio e enxofre; c) avaliar o efeito de nitrogênio e de enxofre na adubação do capim-Marandu na extração desses elementos do solo, na matéria orgânica, no pH e nas frações mineral e orgânica de nitrogênio e de enxofre do solo; e d) avaliar alterações na fisiologia e no metabolismo de gramínea que afetam a produção da planta, em virtude da adubação combinada de formas de nitrogênio e doses de enxofre. Plantas de capim-Marandu foram cultivadas em casa de vegetação em solo classificado como Neossolo Quartzarênico, no período de janeiro a maio de 2006 (três períodos de crescimento). Estudaram-se cinco doses de nitrogênio (0; 100; 200; 300 e 400 mg dm-3) combinadas com cinco doses de enxofre (0; 10; 20; 30 e 40 mg dm-3), em um fatorial 52 fracionado. Utilizando-se a planta-modelo Hordeum vulgare (cevada) testaram-se formas de nitrogênio e doses de enxofre na fisiologia e metabolismo de gramínea, em experimentos com solo e solução nutritiva. A interação doses de nitrogênio x doses de enxofre na adubação foi significativa para área foliar total, número de perfilhos, massa seca da parte aérea, concentração de nitrogênio e relação N:S na planta e teores de nitrogênio total e enxofre-sulfato do solo em pelo menos um dos três ciclos de crescimento do capim-Marandu. O uso de nitrogênio e de enxofre na adubação na relação N:S média de 10:1 aumentou a eficiência do uso da água e maximizou a produção de massa seca, com concentrações de nitrogênio e de enxofre ótimas para o metabolismo da planta e produção de forragem, bem como manteve e/ou incrementou a fertilidade do solo em relação aos referidos nutrientes. Altas doses de nitrogênio combinadas com baixas doses de enxofre na adubação diminuíram expressivamente o nitrogênio absorvido pelas plantas. Os teores de nitrogênio total e das formas nítrica e amoniacal do solo variaram em função do nitrogênio adicionado via adubação e da remoção pelas plantas. O cultivo do capim- Marandu associado à adubação sulfatada incrementou a fração enxofre-éster do solo. O enxofre orgânico residual do solo mostrou-se como potencial fonte de enxofre na nutrição da Brachiaria brizantha cv. Marandu. O fornecimento de nitrogênio na forma de nitrato aumentou os efeitos deletérios da limitação de enxofre para a cevada, por diminuir a atividade da enzima redutase do nitrato e aumentar a concentração de nitrato e de aminoácidos livres no tecido vegetal, principalmente de asparagina e glicina.The nitrogen and sulphur availability in soil might influence plant growth, affecting the vegetal production. The objectives of this work were: a) to assess fertilization with nitrogen and sulphur rates on yield of Brachiaria brizantha cv. Marandu (Marandu palisadegrass) under establishment in a soil supporting degrading pasture of Brachiaria decumbens (Signal grass); b) to evaluate the water use efficiency by Brachiaria brizantha cv. Marandu under establishment and fertilized with nitrogen and sulphur rates; c) to study nitrogen and sulphur rates on Brachiaria brizantha cv. Marandu as affecting the uptake of these elements, soil organic matter, soil pH and soil organic and mineral fractions of nitrogen and sulphur; and d) to evaluate changes in the physiology and metabolism of graminaceous plant linked to yield, and influenced by fertilization with forms of nitrogen and sulphur rates. Marandu palisadegrass plants were grown in a greenhouse with an Entisol, from January to May 2006 (three growth periods). Five rates of nitrogen (0; 100; 200; 300 and 400 mg dm-3) and five rates of sulphur (0; 10; 20; 30 and 40 mg dm-3) were studied in a 52 fractionated factorial. The influence of nitrogen forms and sulphur rates on physiology and metabolism of graminaceous plant was tested using the model plant Hordeum vulgare (barley) grown in soil and in nutrient solution. The interaction nitrogen rates x sulphur rates was significant on leaf area, tiller number, above-ground dry matter, nitrogen concentration and N:S ratio in plants, and on total nitrogen and sulfate-sulphur in the soil in at least one of the three growths of Brachiaria brizantha cv. Marandu. Nitrogen and sulphur ratio in the fertilizer rate about 10:1 increased the water use efficiency by plants and promoted high yield, with adequate nitrogen and sulphur concentration for plant metabolism and forage production, as well as kept and/or raised the soil fertility attributes related to these nutrients. High nitrogen rates in the fertilization without sulphur supply decreased plant nitrogen uptake from the soil. Total nitrogen, nitrate and ammonium concentrations in the soil were affected by nitrogen supply and plant uptake. Growth of Marandu palisadegrass associated with sulphur supply increased the ester-bonded sulphur fraction in the soil. The soil residualsulphur fraction can be considered a sulphur potential source for Marandu palisadegrass mineral nutrition. Sulphur deficient barley plants grown with nitrate as nitrogen source showed low nitrate reductase activity, high nitrate and free amino acids concentration, specially asparagine and glicine.
17
Pask, Christopher Martin. "Magneto-structural correlations of some novel sulfur-nitrogen radicals". Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619955.
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18
Shi, Heng. "Supercritical Fluid Chromatography with Chemiluminescent Nitrogen and Sulfur Detection". Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30546.
Testo completoAbstract (sommario):
The need for sensitive and selective detectors in supercritical fluid chromatography (SFC) is particularly evident since SFC can be used to analyze classes of compounds that are not readily amenable to either gas chromatography (GC) or liquid chromatography (LC). These compounds include species that are nonvolatile or thermally labile and , in addition, contain no chromophore that can be used for spectrophoto detection. The objective of this research is therefore to interface selective chemilumninescent detectors with SFC in the sensitive detection of nitrogen- and/or sulfur containing compounds.
The chemiluminecent nitrogen detector (CLND), a gas-phase detector which is specific for nitrogen-containing compounds, was first evaluated as a detector for use with capillary SFC. The potential use of the CLND for food flavor and petroleum samples was demonstrated. In addition to equimolar nitrogen response, the CLND showed good sensitivity and large linear dynamic range. Minimum detectable quantity (MDQ) was 60 pg of nitrogen with a linear range of over 3 orders of magnitude. Nitrogen to carbon selectivity of 105 was obtained. Capillary SFC with simultaneous flame ionization and chemiluminescent detection was also demonstrated.
The second portion of the research investigated the CLND for packed column SFC with methanol modified CO2. The only modification made in the CLND for packed column SFC is the pyrolysis furnace. The CLND and UV were used to interface with SFC via a post-column split. Methanol-modified CO2 was also demonstrated to be compatible with the CLND even with a high mobile phase flow rate. The use of pressure and modifier programs appears to be feasible as is evidenced by the baseline studies which have been performed, as well as by the applications demonstrated.
The last portion of the research focused on the evaluation of a new generation sulfur chemiluminescent detector (SCLD), which is also a gas-phase detector, with packed column SFC using both pure and methanol modified CO2. The minimum detectable quantities were determined to be 2.6 pg or 14 pg sulfur for mobile phase employing pure CO2 or 8% methanol modified CO2 respectively. The evaluation study also showed excellent selectivity and linearity, as well as day-to-day repeatability. The capabilities of the SFC-SCLD system for sulfur speciation and detection of thermally labile pesticides and polar sulfonamides, as well as petrochemical samples were presented.Ph. D.
19
Deshpande, S. R. "Synthetic studies in bioactive nitrogen, oxygen and sulfur heterocycles". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1991. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2997.
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20
Prosser, Wendy Anne. "Nitrogen nutrition in an aphid symbiosis". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316852.
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21
Meakins, Tracey Suzanne. "The influence of dietary nitrogen intake on urea-nitrogen salvage in the colon". Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243079.
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22
Jacobsson, Michael B. "Synthesis of new multidentate ligands containing nitrogen, oxygen and sulfur". Ann Arbor, Mich. : ProQuest, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1440170.
Testo completoAbstract (sommario):
Thesis (M.S. in Chemistry)--S.M.U., 2007.Title from PDF title page (viewed Mar. 18, 2008). Source: Masters Abstracts International, Volume: 45-02, page: 0867. Adviser: David Y. Son. Includes bibliographical references.
23
Yuen, Yue Tai. "Trithiazyl trichloride in the synthesis of sulfur-nitrogen heterocyclic compounds". Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362732.
Testo completo
24
Spencer, Douglas J. E. "Synthetic models for metalloenzymes containing sulfur, nitrogen and oxygen donors". Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312054.
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25
Kearns, Peter. "The synthesis of highly functionalised chiral nitrogen and sulfur heterocycles". Thesis, University of Liverpool, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415654.
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26
Stotereau, Peter James. "Complexation of transition metal ions with sulfur-nitrogen donor ligands". Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292922.
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27
Alberola-Catalan, Antonio. "Synthesis and physical studies on some novel sulfur-nitrogen radicals". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616073.
Testo completo
28
Mann, S. E. "New reactions of cyclic oxygen, nitrogen and sulfur acetal derivatives". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1317775/.
Testo completoAbstract (sommario):
This thesis describes the development of new reactions of cyclic oxygen, nitrogen and sulfur acetal derivatives and their applications in a diverse range of synthetic organic and organometallic chemistry. Detailed herein are advances in three main areas of acetal chemistry, namely: studies towards a new methodology for the synthesis of medium ring heterocycles; the use of thioacetals as directing groups for the palladium-mediated oxidation of olefins; and multi-component reactions for the synthesis of drug-like heterocyclic compounds. A brief overview of the chemistry of cyclic acetal derivatives is given in the first chapter, followed by a chapter on each of the three areas investigated. Relevant introductory literature is reviewed at the beginning of each chapter. Firstly, the ring expansion chemistry of unsaturated cyclic oxygen, nitrogen and sulfur acetal derivatives was explored for the development of a new methodology for the synthesis of medium ring heterocycles. This methodology has thus far proved unsuccessful in the synthesis of medium rings, although several interesting and unusual transformations were observed, such as the unexpected formation of an intriguing bicyclic enaminium salt. The use of thioacetals as directing groups for the palladium-mediated oxidation of terminal olefins was also explored, leading to the evolution of a new methodology for the catalytic, regioselective formation of either vinyl or allylic acetates. Dithianes were shown to stabilise intermediates in the allylic oxidation pathway, allowing their structure elucidation and characterisation by low-temperature NMR spectroscopy and in one case X-ray crystallography. This enabled a detailed mechanistic study leading to the observation of two finely balanced, divergent reaction mechanisms. Finally, building upon previously unpublished results, a number of three and four-component reactions were investigated, giving drug-like α-aminoamides; this methodology was applied to the synthesis of some medium ring heterocycles.
29
Thompson, Kristopher Michael. "Kinetic Investigation of the Gas Phase Atomic Sulfur and Nitrogen Dioxide Reaction". Thesis, University of North Texas, 2011. https://digital.library.unt.edu/ark:/67531/metadc68055/.
Testo completoAbstract (sommario):
The kinetics of the reaction of atomic sulfur and nitrogen dioxide have been investigated over the temperature range 298 to 650 K and pressures from 14 - 405 mbar using the laser flash photolysis - resonance fluorescence technique. The overall bimolecular rate expression k (T) = (1.88 ± 0.49) x10-11 exp-(4.14 ± 0.10 kJ mol-1)/RT cm3 molecule-1 s-1 is derived. Ab initio calculations were performed at the CCSD(T)/CBS level of theory and a potential energy surface has been derived. RRKM theory calculations were performed on the system. It is found that an initially formed SNO2 is vibrationally excited and the rate of collisional stabilization is slower than the rate of dissociation to SO + NO products by a factor of 100 - 1000, under the experimental conditions.
30
Chen, Xiaoping. "Synthesis, structure and catalytic property of transition metal complexes with phosphorus-nitrogen and sulfur-nitrogen ligands". HKBU Institutional Repository, 2002. http://repository.hkbu.edu.hk/etd_ra/361.
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31
CAVALLARO, VIVIANA. "SULFUR NUTRITION AND PARTITIONING IN RICE UNDER DIFFERENT STRESS CONDITIONS". Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/881847.
Testo completoAbstract (sommario):
Sulfur (S) is an essential macronutrient required by plants for their correct development. This element is fundamental for the biosynthesis of different compounds, such as the two amino acids, cysteine (Cys) and methionine (Met), vitamins (biotin and thiamine), peptides involved in the response to abiotic stresses (glutathione - GSH, and phytochelatines - PCs), lipids and co-factors. Sulfate (SO42-) is the main S form taken up from soil by root system and then assimilated inside the cells during the sulfur reductive pathway. The uptake and the systemic movements of this anion are accomplished by the SULfate TRansporter (SULTR) gene family, which encode for H+/SO42- membrane co-transporters with different localization, amino acidic sequences, and affinity to sulfate. Since has been demonstrated that S has a key role in the response to different abiotic stresses (such as sulfur deficiency, heavy metal exposure or salt stress), the expression of these genes must be finely regulated, according to the different environmental conditions and requests for S reduced compounds.
The general aim of the present thesis is the description of S systemic fluxes in rice in different stress conditions, to obtain more information about the contribution of S in determining plant tolerance to abiotic stresses. To achieve the goal, we also took advantage of analysis performed with an elemental analyzer coupled with an isotope ratio mass spectrometer (EA-IRMS), a powerful instrument which utilizes stable isotopes of elements as tracers.
The entire research has been divided in three different parts.
In the first work, potential 32S/34S isotope effects occurring during SO42- uptake were investigated in a closed hydroponic system in which a limited amount of substrate (SO42- in the nutrient solution) was continuously removed from the solution by the activity of the sulfate transporters of the root and converted in a final product (total S of the plant). An isotope discrimination against 34S occurred during SO42- uptake: plants had a lighter S isotope composition, and the residual SO42- in the hydroponic solution was enriched in heavy stable isotope. Fractionation during uptake showed two phases characterized by different fractionation factors, reflecting changes in the expression of the OsSULTR deputed to the root uptake which may explain the different isotope phenotypes observed during plant sulfate acquisition. Moreover, the possible 32S/34S isotope effects associated to both S partitioning and metabolism were investigated by comparing plants pre-grown in complete nutrient solutions and then continuously maintained on media containing SO42- (steady-state) or deprived of SO42- for 72h. The SO42- pool of the steady-state shoot was significantly 32S depleted with respect to the SO42- pools of root, while the organic S (Sorg) pools were significantly depleted in 34S compared to both the SO42- pool of both the organs and the S source. These results suggested a higher S assimilation in the aerial part of plants which favor the lighter isotope. Under S starvation, S assimilation progressively enriched the Sorg pools in the lighter 32S isotope and the residual SO42- in both the organs in the heavier 34S isotope. Most pronounced isotope separations were again observed in the shoot, confirming the prominent role of this organ in SO42- assimilation and S allocation. No fractionation due to translocation activity was observed.
In the second part of the work, to validate the results previously obtained, we performed a mass balance study in rice plants exposed for 72h to different Cd concentrations, to investigate possible changes in S stable isotope fractionation due to this stress: in fact, adaptation of S metabolism has a pivotal role in responses to heavy metal exposure. As expected, Cd treatment strongly enhanced SO42- uptake and assimilation, as indicated by the analyses of the S pools (Stot, SO42-, and Sorg). S isotope analyses performed on the whole plants revealed changes in the S metabolism associated to variations in the discrimination against 34S, which was less evident as Cd concentration in the external medium increased. Transcriptional analysis suggested again that change of the ratio between relative transcripts of OsSULTR1;1 and OsSULTR1;2, as observed for S starvation, may be responsible for the progressive decreased in 34S isotope discrimination. The important role of shoot in S assimilation was confirmed: isotope fractionation associated to sulfate assimilation was higher in shoot than in root, and progressively increased as Cd concentration did.
The last part of work was focused on fully characterize, under hydroponics-controlled conditions in the absence or in the presence of salt stress (80 mM NaCl), the phenotypic behavior in the already available salt tolerant introgression line (IL) Onice 11 (O11), obtained by Marker-Assisted Back-Cross (MABC) selection starting from the cross between the Italian japonica elite cultivars Onice (sensitive recurrent parent) and the indica variety IR64-SalTol (tolerant), donor of the major QTL SalTol. Moreover, S acquisition and metabolism of O11 and both the parental lines were evaluated to investigate their possible implication in determining the different tolerance to salt stress. Results showed the beneficial effect of the introgression of the SalTol QTL from the indica variety into selected japonica rice line, based on different characteristics of selected phenotypic-biochemical-physiological parameters. However, salt stress strongly affected S uptake and assimilation, and we can reasonably suppose that these features do not justify the different salt tolerance in the considered IL O11.
In conclusions, rice plants can discriminate against 34S during SO42- uptake and assimilation. Between plants organs, shoot represents the predominant one involved in S assimilation. Abiotic stresses, such as S starvation or Cd exposure, lead to changes in the ratio of relative transcripts between the OsSULTRs involved in the uptake of sulfate, and this may be the cause of the different isotope phenotypes observed. Finally, salt tolerance in the IL O11 appears to not be dependent on different S metabolism.
32
Asih, A. Rai Somaning. "Nitrogen utilization and production of dairy goats fed different nitrogen sources /". St. Lucia, Qld, 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16142.pdf.
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33
Witek, Rachel M. "Studies in synthetic methodology routes to sulfur- and nitrogen-containing compounds /". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011359.
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34
Cunningham, Beth. "Density functional studies of sulfur-nitrogen and period 2 fluoride molecules". Thesis, University of Hull, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421982.
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35
Longridge, John Jethro. "A mechanistic investigation of synthetic routes to novel sulfur-nitrogen chains". Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624952.
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36
Burke-Scoll, Medora J. "Nitrogen and sulfur input and accumulation in continental ombrotrophic peatland ecosystems in Alberta, Canada". Click here for download, 2008. http://proquest.umi.com/pqdweb?did=1588775581&sid=1&Fmt=2&clientId=3260&RQT=309&VName=PQD.
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37
Jewmaidang, Jirasak. "Homogeneous sulfur tri-oxide formation in gas reburning for nitrogen oxides control". Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175801641.
Testo completo
38
Grabarczyk, Daniel Ben. "Molecular characterisation of bacterial proteins that interact with sulfur or nitrogen compounds". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:b6b3e3fd-620f-467d-b063-01311fa7a9a2.
Testo completoAbstract (sommario):
Many bacteria use inorganic nitrogen and sulfur compounds for energy metabolism. These compounds are often toxic and so bacteria must adapt to survive their deleterious effects. Bacteria use specific proteins in order to metabolise, sense and detoxify these compounds. In this thesis protein interactions with inorganic nitrogen and sulfur compounds are examined at the mechanistic level. Intermediates in the Sox sulfur oxidation pathway are covalently attached to a cysteine on the swinging arm of the substrate carrier protein SoxYZ. An interaction between the Sox pathway enzyme SoxB and the carrier protein SoxYZ is demonstrated. A crystal structure of a trapped SoxB-SoxYZ complex at 3.3 Å resolution identifies two sites of interaction, one between the SoxYZ carrier arm and the SoxB active site channel and the other at a patch distal to the active site. The presence of a distal interaction site suggests a mechanism for promiscuous specificity in the protein-protein interactions of the Sox pathway. Using biophysical methods it is shown that SoxB distinguishes between the substrate and product forms of the carrier protein through differences in interaction kinetics and that the carrier arm-bound substrate group is able to out-compete the adjacent C-terminal carboxylate for binding to the SoxB active site. The thiosulfate dehydrogenase TsdA has an unusual His/Cys coordinated heme. TsdA catalyses oxidative conjugation of two thiosulfate molecules to form tetrathionate. Mass spectrometry and UV/visible spectroscopy are used to identify an S-thiosulfonate reaction intermediate which is covalently attached to the cysteine heme ligand. A catalytic mechanism for TsdA is proposed using a crystal structure of TsdA at 1.3 Å resolution alongside site-directed mutagenesis of active site residues. Nitric oxide is produced by the mammalian immune response to kill bacterial pathogens. Part of the killing mechanism occurs through the reaction of nitric oxide with protein-bound iron-sulfur clusters. However, the same type of reaction is also exploited by nitric oxide-sensing bacterial proteins. An infrared spectroscopy approach is developed to detect the products of iron-sulfur protein nitrosylation. Using this methodology it is shown that the presence of trace O2 strongly impacts which products are formed in these nitrosylation reactions. These observations are of physiological relevance because bacteria are often exposed to NO under aerobic conditions during an immune response.
39
Munro, Andrew P. "S-nitrosothiols : novel decomposition pathways including reactions with sulfur and nitrogen nucleophiles". Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4605/.
Testo completoAbstract (sommario):
Spectrophotometric (including stopped-flow) techniques were used to examine the kinetics of NO-group transfer reactions (transnitrosation) between S-nitrosothiols (RSNO) and a wide range of sulfur/nitrogen nucleophiles in aqueous solution. A metal-ion chelator was added in all experiments to prevent RSNO decay and NO liberation catalysed by copper ions. In most cases reaction was envisaged as rate- determining attack of the nucleophile at the nitrogen atom of the -SNO moiety, and hence S-nitrosothiols essentially acted as electrophilic nitrosating agents. Sulfite, thiosulfate, thiourea, thiocyanate and thiomethoxide, were sufficiently nucleophilic to induce nitrosothiol decomposition at physiological pH. Reaction with sulfide (pH > 7.4) afforded the orange-yellow anion, SSNO, and embodies a potential quantitative test for RSNOs. S-Nitrosopenicillamine was reactive enough to allow a thorough investigation into its reaction at basic pH with primary, secondary (creating carcinogenic N-nitrosamines), and tertiary amines, as well as ambident (e.g. thiomorpholine) and alpha nucleophiles (e.g. azide ion). Parallels could be made with analogous studies using other nitroso compounds such as MNTS. The generality of the reaction of a S-nitrosothiol with a large excess of the corresponding or a different thiol was also assessed. Ammonia and not nitric oxide was confirmed as the primary nitrogenous product of this highly complicated process. Mechanistic details of the copper(I) catalysed decomposition of some novel S- nitroso derivatives (e.g. a synthesised S-nitroso-1 -thiosugar) are reported. The two- stage degradation pathway involved an initial Cu(^+) promoted component that halted at incomplete conversion, and was accompanied by a large thermal reaction. An explanation of this unique pattern has been offered in terms of the generation of a disulfide-Cu(^2+) complex, in which copper is/is not accessible to reduction.
40
Berlanga, Jesus Alejandro. "Kinetic Modeling of the Atmospheric Photooxidation of Reduced Sulfur and Nitrogen Compounds". TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/2686.
Testo completoAbstract (sommario):
Atmospheric aerosols encapsulate a wide variety of particles with different compositions, sizes and sources of origin. They also directly and indirectly affect climate by their interactions with sunlight, clouds, atmospheric chemical species, and even other suspended particles. To understand the atmospheric aerosol processes and the effects they have in global and regional climate is of utmost importance for the future establishment of environmental regulations and emission policies that affect aerosol precursor compounds in an effective and beneficial manner. In particular, aerosols are known to be formed from emissions from human activities, such as fossil fuel burning, agriculture, or concentrated animal feeding operations (CAFOs). Secondary organic aerosols (SOA) constitute a type of atmospheric aerosols that are formed from the atmospheric oxidation of organic compounds that are released from various sources into the atmosphere. Due to the complexity of the atmosphere and variability of its conditions, the direct study of SOA formation is a challenging task, but the implementation of atmospheric chamber facilities to study aerosol formation and growth under controlled conditions has provided a way to study the formation and growth of SOA. However, chamber experiments cannot study specific reactions or individual compounds from the aerosol formation mechanisms in isolation, they can only provide insight on what is produced and what it is produced from, and under what conditions. Thus, kinetic modeling of the mechanisms of gas-phase atmospheric oxidation of the compounds of interest is used to develop reliable and accurate chemical models that will help have precise estimations and determine the mechanisms by which volatile organic compounds interact to produce aerosol particles. Dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and trimethylamine (TMA) are three relevant atmospheric compounds, due to their emissions from many natural and anthropogenic sources and recent studies on emissions of these compounds from animal waste from CAFOs has triggered the interests on the study of SOA formation from these and other similar compounds. In this study, kinetic modeling of the atmospheric oxidation mechanisms of DMDS, DMS and TMA is used to simulate atmospheric chamber studies of aerosol formation to develop accurate models and help determine the mechanisms of aerosol formation.
41
Harney, Dennis James. "The Physiological and Developmental Effects of Sulfur Nutrition and Light Intensity on Sulfur Deficiency Symptoms in Phaseolus Vulgaris". Oxford, Ohio : Miami University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1050520818.
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42
Seeyave, Sophie. "Nitrogen nutrition of harmful algal blooms in upwelling systems". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/145737/.
Testo completoAbstract (sommario):
Blooms of toxic, or otherwise harmful phytoplankton species are known to occur in eastern boundary upwelling systems, coincident with the relaxation of upwelling in late summer/autumn. Field studies were carried out in 3 consecutive summers (March/April 06-08) in the Benguela and in the autumn (Sept 06) and summer (June 07) in the Iberian upwelling system (Ría de Vigo), with the aim of identifying common nitrogen nutrition strategies of HAB species that may allow them to succeed in upwelling systems. Two summer field studies were also carried out in the Fal Estuary (UK) to identify possible differences between a UK estuary and these upwelling systems. In the Benguela, three toxic phytoplankton species were dominant under different nutrient conditions. Pseudo-nitzschia spp. were abundant during a period of strong upwelling and high NO3-, peaking during short periods of wind relaxation. During these periods, a switch from high nitrate uptake [(NO3 -)] to regenerated nitrogen uptake [(NH4 +) and (urea)] occurred, with ƒratios dropping from 0.79 to 0.12. Alexandrium catenella bloomed during a period of upwelling, displaying high (NO3-) and ƒ-ratios up to 0.87. Dinophysis acuminata dominated when NO3 - concentrations were <0.5 μmol l-1 and ƒ-ratios <0.1 in 2007, although in 2008 it formed a subsurface maximum, often associated with high NO3- concentrations. Nutrient uptake kinetics showed that Pseudo-nitzschia spp. displayed the highest maximum specific uptake rates (max). D. acuminata displayed the highest affinity for NH4+, as shown by its values (slope of the nutrient uptake vs. concentration curve). Thus, A. catenella was adapted to utilising high NO3- concentrations during upwelling pulses, whereas both Pseudo-nitzschia and D. acuminata were able to acclimate to both high and low NO3- concentrations during the upwelling/relaxation cycles. In the Ría de Vigo, warm water from the stratified shelf entered the ría and downwelled in September, resulting in a well-mixed water column. The phytoplankton assemblage, dominated by Ceratium spp., Dinophysis acuminata and Gymnodinium catenatum, appeared to be advected in to the ría. Nitrate concentrations were consistently low, whereas NH4+ concentrations increased towards the head of the ría and with depth. The phytoplankton community was dependent on regenerated nitrogen, with ƒ-ratios <0.2. In contrast, positive circulation in June resulted in strong vertical gradients in temperature, salinity and nutrients and a community dominated by diatoms. Nitrate and NH4+ were depleted in surface waters although uptake rates were higher than in September, as were the ƒ-ratios (0.1-0.3). In both systems, upwelling winds favoured diatoms, although they were able to utilise regenerated nitrogen when NO3- was depleted, whereas upwelling relaxation created favourable conditions for HAB development. Dinophysis spp. occurred in both systems and were able to grow on recycled nitrogen in the absence of NO3-. The Benguela showed high variability in the selection of particular HAB species, perhaps due to greater variability in upwelling-downwelling cycles. In the Ría de Vigo, the occurrence of downwelling and associated nutrient conditions leading to blooms of Dinophysis spp. and Gymnodinium catenatum seems more predictable. In the Fal Estuary, Alexandrium spp. was favoured by low irradiance and the combination of strong stratification and high nutrient concentrations, and its growth was sustained predominantly by NH4+. A. minutum strains isolated from both upwelling systems and from a UK Lagoon all displayed higher max for NH4+ relative to NO3- but higher growth rates on the latter. This was consistent with field results from all 3 regions, suggesting that the upwelling systems did not display a different order of nitrogen preference, although they did display a higher affinity for NO3-.
43
Lok, Eng Hai. "Nutrition and nitrogen-fixation in Malaysian Pterocarpus Indicus willd". Thesis, Lok, Eng Hai (2011) Nutrition and nitrogen-fixation in Malaysian Pterocarpus Indicus willd. PhD thesis, Murdoch University, 2011. https://researchrepository.murdoch.edu.au/id/eprint/5831/.
Testo completoAbstract (sommario):
Pterocarpus indicus is a promising tropical woody legume for the establishment of forest plantations in Malaysia. Woody legumes that form symbiotic relationships with nitrogen-fixing bacteria also play an important role for forest restoration on degraded land. Although P. indicus has been widely planted as an amenity tree in SE Asia, its silvicultural requirements have not been determined. There are no recommendations for fertilizer or for inoculation with nitrogen-fixing bacteria. This thesis explores the phosphorus (P) and nitrogen (N) requirements of seedlings and identifies a range of nitrogen-fixing bacteria capable of forming root nodules under glasshouse conditions.
Four glasshouse experiments were undertaken on two soil types: Yalanbee sandy gravel (YB) and yellow sand (YS) to determine the P and N concentration ranges in the foliage of deficient and healthy plants and to define critical nutrient concentrations for the diagnosis of deficiency. There was a narrow range in rates of P fertilizer, supplied as aerophos, Ca(H2PO4)2.H2O, between deficiency and toxicity in both soil types. The relationship between yield and P concentration in the youngest fully expanded leaf (YFEL) enabled critical P concentrations for the diagnosis of deficiency (0.17%) and toxicity (0.41%) to be determined at 90% maximum yield from linear regressions fitted to the data. The foliar P concentration ranges for deficiency and toxicity were similar to other nitrogen-fixing trees. Only plants in YS responded to inorganic N fertilizer, and soil analysis suggested that seedlings may take up ammonium-N in preference to nitrate-N at luxury supply. A critical concentration for the diagnosis of N deficiency was not able to be determined due to the lack of data points. Plants with adequate N fertilizer had YFEL N concentrations of 2-3.5% dry weight.
To determine whether P. indicus is more sensitive to luxury soil P supply than other fast-growing legume trees, the P response of P. indicus in YB was compared with three other woody legumes, Pterocarpus macrocarpus, Acacia mangium and Sesbania formosa. The sensitivity of P. indicus to high P was confirmed and the response shown to be similar to P. macrocarpus. Both species showed severe symptoms of P toxicity, namely leaf necrosis and stunted growth. In contrast, shoot and root yields of A. mangium and S. formosa were not reduced at luxury P supply and yield x fertilizer relationships were able to be fitted to the Mitscherlich model. Critical P concentrations for the diagnosis of P deficiency in A. mangium and S. formosa, derived using the Mitscherlich model, were estimated to be 0.2-0.3% dry weight for the YFELs.
Two glasshouse inoculation trials were carried out using diverse strains of root nodule bacteria in order to identify strains suitable for inoculation in the nursery. There were eight strains from Bradyrhizobium, five from Rhizobium, three from Sinorhizobium and two Mesorhizobium strains. P. indicus formed nodules with strains from Bradyrhizobium, Rhizobium, Sinorhizobium and Mesorhizobium, which suggests it is a promiscuous host. Nodules formed were globose, single and of aeschynomenoid type. In the first trial, Bradyrhizobium strain WSM 2096, promoted shoot growth while in the second trial, Bradyrhizobium strain WSM 3712 promoted shoot growth. Growth stimulation was similar to the uninoculated control supplied with inorganic N as KNO3 but was inferior to plants given (NH4)2SO4.
The response of P. indicus to low soil P in inoculated and uninoculated plants was studied in a pot trial comprising two P treatments (nil, just adequate). Plants were grown for 3 and 6 weeks. At nil fertilizer P, uninoculated P. indicus seedlings had higher total root length and root dry weight than those with adequate P. Inoculation with WSM 3712 suppressed root growth relative to uninoculated plants.
Information gathered in this thesis has application for the production of planting stock in forest nurseries. Firstly, care needs to be taken to ensure that rates of P supplied as hard or liquid fertilizer are not in the range likely to cause toxicity. Secondly, if any starter inorganic N fertilizer is to be used then it should be supplied either as ammonium-N or as urea. Thirdly, more research is required in order to identify effective strains of rhizobia for widespread commercial application. Fourthly, the critical foliar P concentrations identified for the diagnosis of P deficiency and P toxicity can be used to help interpret foliar analysis of seedlings in the future.
44
Harding, Michael. "New concepts in asymmetric catalysis". Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284768.
Testo completo
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Okbinoğlu, Tülin Nesime. "Electronic structure of sulfur-nitrogen containing compounds : correlations with theory and chemical reactivity". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50408.
Testo completoAbstract (sommario):
Molecules containing sulfur-nitrogen bonds, such as sulfonamides, have long been of interest due to their many uses and chemical properties, including the potential release of nitric oxide and nitroxyl. Understanding the factors that cause sulfonamide reactivity is crucial, yet their inherent electronic complex- ity have made them difficult to examine. In this thesis, sulfur K-edge x-ray absorption spectroscopy (XAS) is used in conjunction with density functional theory (DFT) to determine the role of electronic transmission effects through the sulfur-nitrogen bond. A systematic deconstruction of the elements within the sulfonamide moiety is used as an approach to understand critical factors that dictate electronic structure.
First, the effect of oxidation state changes and variations in R-group in sulfenamides, sulfinamides and sulfonamides on intramolecular bonding are explored. Next, N-hydroxylation of the sulfonamide amide, in both alkyl sulfonamides and a series of para-substituted aryl sulfonamides with varying Hammett para-sigma constants are studied using structure-function relationships, in conjunction with DFT, to understand the role of electron donation and withdrawal to the sulfonamide moiety. The outcome of these modifications on the sulfonamide framework lead to better insight towards directed drug design and its influence on nitroxyl and nitric oxide release.Science, Faculty of
Chemistry, Department of
Graduate
46
Huang, Wei Ze. "Dynamics of carbon, nitrogen, phosphorus and sulfur in a boreal aspen forest soil". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23991.pdf.
Testo completo
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Epp, Karen Margaret. "The chemistry of cyclopentadienyliron complexes of arenes with sulfur, oxygen and nitrogen bridges". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0004/NQ41607.pdf.
Testo completo
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Porter, Matthew Kirk. "Regional modeling of nitrogen, sulfur, and mercury atmospheric deposition in the Pacific Northwest". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/M_Porter_082407.pdf.
Testo completo
49
Wolff, Joel Alan 1965. "Synthesis and study of technetium(v) complexes of tetradentate nitrogen-, sulfur-donor ligands". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13102.
Testo completo
50
Ali, Abul Basar. "The incorporation of sulfur, oxygen and nitrogen containing organic molecules into triosmium clusters". Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1445285/.
Testo completoAbstract (sommario):
This thesis describes the oxidative addition reactions of sulfur, oxygen and nitrogen containing organic molecules into triosmium clusters. The products were formed by C-H, O-H, N-H and S-S bond cleavage. The direct reaction of dibenzyl disulfide, di(2-thienyl)disulfide and di-tertiary-butyl disulfide with cluster Os3(MeCN)2(CO)io yielded their respective unsymmetrical thiolato derivatives: Os3(u-SCH2Ph)2(CO)io , Os3(p-StBu)2(CO)i0 and Os3(u- SC4H3S2)2(CO)io in high yields with the cleavage of the S-S bond. Only dibenzyl disulfide gave a second cluster Os3(u-H)(S2CH2Ph)(CO)io , which retained the S-S bond. Thermal treatment of Os3(u-SCH2Ph)2(CO)io gave the symmetrical isomer in which both sulfur ligands bridged the same pair of osmium atoms. The interconversion of isomers of the unsymmetrical form of Os3(u-SCH2Ph)2(CO)io , related by inversion at sulfur, gave Ea = 61.5 2.0 kJ mol"1, determined by NMR methods. The direct reaction of 8-hydroxyquinoline with Os3(MeCN)2(CO)io employing various reaction conditions yielded both mono-, tri- and tetra-nuclear compounds: 0s(C9H6N0)2(C0)2 , 0s3(C9H6N0)2(C0)8 , Os3(u-H)(C9H6NO)(CO)9 and Os4(u- H)(C9H6N0)(C0)ii . Three isomers of complex 0s(C9H6N0)2(C0)2 were observed. Reactions between osmium carbonyl and phenols substituted with both electron- donating or accepting substituents always gave the dienone structures 0s3(u-H)2(u- 0C6H4X)(C0)9 (X = OH, F, OMe) in preference to the alternative aromatic form. The variable-temperature NMR spectra of Os3(u-H)2(u-OC6H40Me)(CO)9 show both the hydrides and the carbonyl ligands are mobile. Attempts to link clusters were only successful with hydroquinone which gave Os6(u-H)3(u-OC6H30)(CO)i9 . However with aminophenol, reaction was always preferred at the amine in preference to the hydroxyl group. Benzoquinone gave a unique cluster Os3(u-H)(u- OC6H5O)(CO)10 . Finally we have shown how the direct reaction of Os3(MeCN)2(CO)io with 4,4- dipyridyl disulfide yields the linked cluster OseCu-HMp-CsCsNXCOo leaving the S-S bond intact. The S-S cleavage occurs by treating Os6(p-H)2(n- C5H3NS2C5H3N)(CO)2o further with Os3(MeCN)2(CO)i0 to give Os9(u-H)2 (NC5fi3S)2(CO)3o . The initial reaction always takes place at the pyridine ligands followed by S-S cleavage. The reaction of 4-mercaptopyridine gave a linked cluster Os6(u-H)2(NC5H3S)(CO)2o . All these reactions were carried out at room temperature.