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Caracterización estructural de zeolitas por Resonancia Magnetica Nuclear y su aplicación como catalizadoresMartínez Ortigosa, Joaquín 26 April 2021 (has links)
[ES] Las zeolitas son sólidos cristalinos microporosos con canales y cavidades de tamaños moleculares, que pueden presentar gran variedad de estructuras y composición química, lo que las hace útiles como catalizadores en gran variedad de procesos químicos. En la presente tesis doctoral, se han estudiado en profundidad las propiedades estructurales de zeolitas con estructura RTH y MFI pura sílice y aluminosilicato, utilizando fundamentalmente la técnica de resonancia magnética nuclear (RMN). Además, se han estudiado catalizadores zeolíticos tipo Ag-FAU para una reacción de interés medioambiental como la Oxidación Catalítica Selectiva de NH3 (NH3-SCO).
En esta tesis, las zeolitas tipo MFI y RTH se han sintetizado utilizando tetraalquilamonios y tetralquilfosfonios como ADEs y HF como agente mineralizante. Los resultados referentes a la zeolita MFI pura sílice indican que el ADE utilizado afecta al orden local de la estructura, a la distribución de flúor y a la formación de defectos de red. En la síntesis de la zeolita tipo MFI aluminosilicato, se ha observado que el ADE utilizado y la relación Si/Al produce diferencias significativas en los espectros de RMN de 27Al, que se atribuyen normalmente a variaciones en la distribución del aluminio en diferentes sitios cristalográficos. Sin embargo, las diferencias desaparecen después de la calcinación, lo que cuestiona esta interpretación. La zeolita tipo RTH pura sílice se ha sintetizado con el catión iPr3MeP+ variando los tiempos y la temperatura de síntesis. Estos parámetros afectan tanto a la estructura local de los átomos de silicio como a la distribución del flúor en la zeolita. Se ha observado también la transformación de la estructura tipo STF a RTH durante la síntesis.
La modificación con fósforo de zeolitas tipo aluminosilicato, que normalmente se realiza por impregnación, estabiliza el aluminio de la red en condiciones hidrotermales, lo que tiene importantes implicaciones en las aplicaciones industriales. En esta tesis, se han incorporado cantidades variables de fósforo en las zeolitas MFI y RTH aluminosilicatos utilizando mezclas de alquilamonios y alquilfosfonios como ADEs. Los resultados indican que el fósforo permanece en las zeolitas después de la calcinación estabilizando el aluminio de red. La caracterización detallada de las muestras ha permitido proponer las especies Al-P formadas, responsables de la estabilización de la red. Además, las zeolitas P-RTH y P-ZSM-5 se han utilizado como catalizadores para la reacción de metanol a olefinas.
Por último, se ha estudiado la influencia de diferentes parámetros como la relación Ag/Al, la presencia de cationes alcalinos o la acidez Brønsted en zeolitas Ag-FAU y sus repercusiones en el comportamiento catalítico para la reacción de NH3-SCO. Los catalizadores se han caracterizado exhaustivamente antes, durante y después de la reacción, observándose que las partículas de plata metálica, que son los centros activos, se re-dispersan y oxidan en condiciones de reacción. / [CA] Les zeolites són sòlids cristal·lins i microporosos amb canals i cavitats de dimensions moleculars, que poden presentar una gran varietat d' estructures i composició química, això les fa molt interessants com a catalitzadors en un ampli nombre de reaccions químiques. En la present tesi doctoral, s'ha estudiat en profunditat les propietats estructurals de les zeolites amb estructura RTH i MFI pura sílice i amb sílici i alumini, utilitzant fonamentalment la tècnica de ressonància magnètica nuclear. A més, s'han estudiat catalitzadors basats en Ag-FAU zeolites per a una reacció d'interès mediambiental com es l' Oxidació Catalítica Selectiva d'amoníac (NH3-SCO). En aquesta tesi, les zeolites tipus MFI i RTH s'han sintetitzat amb l'ús de cations tetraalquilamoni i tetraalquilfosfoni i HF com agent mineralitzant. Els resultats obtinguts per a la zeolita MFI pura sílice mostren com l'ADE utilitzat juga un paper important en l'ordre local dels àtoms de silici, la distribució de fluor i la formació de defectes zeolítics. En la síntesi de la zeolita MFI aluminosilicat, s'ha observat que la natura dels ADEs i la relació Si/Al produeix diferències significatives a l'espectre de 27Al de RMN, normalment associades a una localització diferent de l'alumini. Però eixes diferències desapareixen amb la calcinació de les zeolites. La zeolita RTH pura sílice ha sigut sintetitzada amb el catió iPr3MeP+ modificant les condicions de síntesi (temps i temperatura). Els resultats mostren que l'ordre local dels àtoms de l' estructura zeolítica o la distribució de fluor es veu influenciada per aquests paràmetres. També s'ha pogut observar que en determinades condicions de síntesi es produeix la transformació de la estructura tipus STF en RTH en el procés de síntesi. La modificació amb fòsfor de les zeolites que contenen alumini, que normalment es realitza per impregnació, estabilitza l'alumini de l'estructura zeolítica en condicions hidrotermals, la qual cosa té una importància crucial per a les aplicacions industrials d'aquests materials. En aquesta tesi, s'han incorporat quantitats creixents de fòsfor a les zeolites RTH i MFI aluminosilicats utilitzant mescles d'alquilamonis i alquilfosfonis com ADEs. Els resultats indiquen que tot el fòsfor introduït roman a la zeolita després de la calcinació, estabilitzant l'alumini en la zeolita. La caracterització dels materials ha permès proposar les espècies Al-P formades a l'interior de les zeolites, que són les responsables de l'alta estabilitat hidrotermal de l'alumini a l'estructura zeolítica. A més, les zeolites RTH i MFI modificades amb fòsfor han sigut utilitzades com a catalitzadors en la reacció de metanol a olefines (MTO). Per últim, s'ha estudiat la influència de alguns paràmetres com la relació Ag/Al, la presència de cations alcalins o centres àcids de BrØnsted als catalitzadors tipus Ag-FAU i les seues repercussions per a la reacció de NH3-SCO. Els catalitzadors s'han caracteritzat abans, durant i després de la reacció i els resultats mostren que les nanopartícules de plata metàl·lica són el centre actiu de la reacció i que es re-dispersen i oxiden en condicions de reacció. / [EN] Zeolites are microporous crystalline solids containing channels and cavities of molecular dimensions, which can present different structures and chemical composition, making them especially interesting as catalysts in several chemical processes. In this doctoral thesis, we have deeply studied the structural properties of pure silica and aluminosilicate RTH- and MFI-type zeolites mainly using nuclear magnetic resonance (NMR) spectroscopy. Moreover, we have studied the properties of Ag-FAU zeolites as catalysts for the selective catalytic oxidation of ammonia (NH3-SCO), which is a reaction of great interest for the environmental.
Here, zeolites RTH and MFI have been synthesized in the presence of tetraalkilammonium and phosphonium cations as OSDAs and in fluoride media. The results obtained for the MFI zeolites show that the OSDAs has a strong influence on the local order of the framework, the fluorine distribution and the formation of siloxy/silanol defects. The results for the aluminosilicate MFI-type (ZSM-5) zeolite show that the shape of the 27Al NMR spectrum changes depending on both the OSDA and the Si/Al ratio, which is usually attributed to a different Al sitting in the zeolite. These differences disappear after the calcination of the zeolites, questioning the classical interpretation. RTH-type zeolite has been synthesized using the iPr3MeP+ cation varying the synthesis conditions (time and temperature). The results show that these parameters affect the local environment of the silicon atoms and the fluorine distribution inside the zeolite. It has been also possible to identify the zeolitic transformation of the STF structure into the RTH-type during the synthesis.
The introduction of phosphorus in the aluminosilicate zeolites, usually done by the impregnation procedure, stabilizes the framework aluminium under steam conditions, with important implications in industrial processes. In this doctoral thesis, we have varied the P/Al molar ratios using the dual-template synthesis technique. All phosphorus from the P-based OSDAs remain inside the zeolites after the thermal/hydrothermal treatments. The exhaustive characterization of the materials has allowed us to propose the Al-P species formed inside the zeolites responsible of the aluminium stabilization. Moreover, some phosphorus modified RTH and MFI zeolites were tested in the methanol to olefins (MTO) reaction.
Finally, we have studied the influence of different parameters such as the Ag/Al ratio, the alkali cations or the presence of BrØnsted acid sites in the Ag-FAU zeolites and its implications in the NH3-SCO reaction. The Ag-FAU catalysts have been deeply characterized before, during and after the catalytic tests, identifying the Ag0 specie, which is the active centre for this reaction, and that metal particles are re-dispersed and oxidized under reaction conditions. / Martínez Ortigosa, J. (2021). Caracterización estructural de zeolitas por Resonancia Magnetica Nuclear y su aplicación como catalizadores [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165576
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Managerial data management applications utilising periodic data outputs from multiple legacy systems : a case within DaimlerChrysler AGTheron, Frederik J 12 1900 (has links)
Thesis (MBA)--Stellenbosch Unversity, 2006. / ENGLISH ABSTRACT: In project environments where periodical. standardised data exports from large relational databases serve as the source data for further repetitive manipulation, relational principles can be applied to automate or facilitate this process. The subsequent data model is only valid in environments where the recipient of these data exports has no influence on the data content or
structure, and where it can be relied upon these standardised exports not to change significantly over time. This paper discusses the development of a data application within the Development department of DaimlerChrysler AG that utilises standardised data objects as data sources, along with various aspects of the Relational and Entity models that enabled additional user generated
data to be related to the data structure. It further provides a brief introduction into Agile development strategies and iterative problem solving techniques as it pertains to database development. A working build of the application containing all the source code along with a
representative data set is supplied on a CD. / AFRIKAANSE OPSOMMING: In projek omgewings waar standaard, periodiese data stelle dien as die bron vir verdere
repeterende data manupulasie kan data verhoudings modelle gebruik word om die proses te outomatiseer. Die werkende data model wat hierdeur gegenereer word is slegs geldig indien die klient geen beheer kan uitoefen oor die data struktuur of inhouds vorm wat as bron gebruik word nie. Dit moet ook geredelik aanvaar kan word dat die gestandardiseerde data struktuur nie
wesenlik sal verander met tyd nie. Die studie stel ondersoek in na die ontwikkeling van 'n data program binne die ontwikkelingsdepartement van DaimlerChrysler AG asook verskye beginsels aangaande die verhoudings en entiteits modelle soos van toepassing op die ontwikkelde program.
Gestandardiseerde data stelle dien as 'n periodiese data bron vir hierdie program en word deur verhoudings beginsels gekoppel aan data wat deur gebruikers gegenereer word. 'n Werkende kopie van die program gepaartgaande met 'n verteenwoordigende data stel asook alle oorspronklike programerings kode word op 'n CD voorsien.
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Differential roles of the two major endocannabinoid hydrolyzing enzymes in cannabinoid receptor tolerance and somatic withdrawalSchlosburg, Joel 21 April 2010 (has links)
While there is currently active debate over possible therapeutic applications of marijuana and cannabis-based compounds, consistently their primary drawbacks have been the psychoactive properties, dependence, and abuse potential. Prolonged administration of ∆9-tetrahydrocannabinol (THC), the primary psychoactive constituent in marijuana, demonstrates both tolerance and physical withdrawal in both preclinical and clinical studies. Repeated THC administration also produces CB1 receptor adaptations in the form of reduced activation of receptors, along with a downregulation of membrane surface receptors, in many brain regions involved in THC-associated behaviors. The increased need for drug to maintain therapeutic effects, and a withdrawal syndrome following discontinuation of use, are common risk factors in drugs of abuse. Recently, compounds have been developed that prolong the availability of the major naturally occurring endogenous cannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), through inhibition of their catabolic breakdown by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), respectively. The overall objectives of this research are to elucidate the physiologic roles of these two endogenous ligands and to determine if either can produce beneficial therapeutic effects without negative cannabis-like CNS effects. Therefore, we tested the impact of acute and prolonged blockade of FAAH and MAGL on a variety of cannabinoid-mediated behaviors and on precipitated cannabinoid withdrawal. Despite that acute blockade of FAAH and MAGL produce similar efficacy in reducing nociceptive responses, and both can reduce THC-induced somatic withdrawal, sustained blockade of these enzymes leads to remarkably different adaptations in CB1 receptor functioning. Namely, prolonged elevations in brain 2-AG leads to marked antinociceptive tolerance, cross-tolerance to exogenous cannabinoid agonists, and physical dependence. In contrast, sustained elevations in brain anandamide continues to dampen pain responses without apparent signs of physical withdrawal, loss of CB1 receptor activation as measured by [35S]GTPγS, or receptor downregulation as measured by [3H]CP,55940. These results suggest that chronic 2-AG elicits greater compensatory changes in CB1 receptor functions than anandamide. With similar efficacy in most therapeutic endpoints tested, and evidence of reduced impact on long-term function of the endocannabinoid system, these results distinguish FAAH as a more promising therapeutic target to treat pain and other conditions than MAGL.
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Cannabinoid Modulation of Reinforcement Maintained by Stimulation of the Medial Forebrain Bundle in C57Bl/6J MiceWiebelhaus, Jason 20 September 2013 (has links)
Cannabinoid agonists, including marijuana containing delta-9-tetrahydrocannabinol (THC), are found rewarding by humans. In addition to human self-reports and experimental studies that show marijuana is rewarding, contributions from preclinical studies also have implicated cannabinoid receptors in reward-motivated behavior. One way to assess these preclinical effects of cannabinoids is intracranial self-stimulation (ICSS), where an animal performs a response to receive electrical stimulation of a specific brain area or circuit known to be involved in reward. Drugs of abuse, such as psychomotor stimulants, facilitate responding for ICSS. While a few studies have shown facilitating effects of cannabinoids in rats, several have shown the opposite effect, and no studies so far have evaluated cannabinoids in mouse ICSS. Furthermore there are no studies evaluating specific inhibitors of endocannabinoid catabolic enzymes in ICSS in any species. In these studies we assessed the cannabinoid agonist THC, as well as the fatty acid amide hydrolase (FAAH) inhibitor, PF-3845, the monoacylglycerol lipase (MAGL) inhibitor JZL184, and the combined FAAH/MAGL inhibitor SA-57 in ICSS of the medial forebrain bundle in C57BL/6 mice. Additionally, we assessed the psychomotor stimulant cocaine as a positive control to facilitate ICSS. These studies were complimented with spontaneous locomotor activity and food-maintained operant experiments to assess the sensitivity of ICSS to cannabinoids. Additionally, brain endocannabinoid levels were measured in brain regions associated with the mesolimbic system after enzyme inhibitor treatments. THC, JZL184, and SA-57 all produced time-dependent reductions in ICSS that were mediated through CB1 receptors, as they were blocked by pre-treatment with the CB1 antagonist rimonabant, but not with the CB2 antagonist SR144528. PF-3845 also reduced ICSS, but did so independent of CB1 and CB2 receptors, and only with one dose (30.0 mg/kg) that has not been assessed previously in vivo. We showed that ICSS was more sensitive to the rate-reducing effects of cannabinoids than other measures of behavior with motor components including spontaneous locomotor activity and operant nose-poking for food, and that the reduction of ICSS produced by both JZL184 and SA-57 is accompanied by increases in 2-AG in mesolimbic brain areas. Thus, cannabinoids do not facilitate ICSS in C57BL/6 mice over a range of doses and pre-treatment times, similar to most studies with rats. These data suggest that cannabinoids may produce rewarding effects through non-mesolimbic areas of the brain.
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Copper isotope compositions of Cenozoic mafic-intermediate rocks of the Northern Great Basin and Snake River plain (USA)Maynard, Annastacia Lin January 1900 (has links)
Master of Science / Department of Geology / Matthew E. Brueseke / Mid-Miocene epithermal Au-Ag ores of the northern Great Basin USA are related to magmatism associated with the inception of the Yellowstone hotspot. The geochemical chemical connection between these ores and spatially and temporally related volcanism is not well understood, but has been suggested (Kamenov, 2007; Saunders et al., 2015). These Cu- and Pb- isotope studies show that the ore and associated gangue minerals have different sources of Pb, which supports evidence that the metal(loids) originate from a deep magmatic source (Saunders et al., 2008). Cu isotopes as a tool for exploring linkages between ore deposits and related volcanic rocks is a new and evolving field. A suite of mid-Miocene Northern Great Basin (NGB) and Snake River Plain (SRP) volcanic rocks was analyzed by aquaregia leach for their δ⁶⁵Cu compositions. These samples have all been previously characterized and include basalts, trachybasalt, basaltic andesites, and basaltic trachyandesites that are representative of regional flood basalt magmatism and younger basalt eruptions in central Idaho. Included are rocks from the Santa Rosa-Calico volcanic field, NV (e.g., Buckskin-National district); Owyhee Mountains, ID (Silver City District); Midas, NV region, near Jarbidge, NV; and a locality proximal to Steens Mountain, OR. Also included are two Pleistocene basalts from the central Snake River plain unequivocally related to the Yellowstone hotspot volcanism (McKinney Basalt and Basalt of Flat Top Butte), and one Eocene basalt from the Owyhee Mountains that is related to pre-hotspot arc volcanism. International rock standards ranging from ultramafic to intermediate were also analyzed in this study for comparison.
Our new δ⁶⁵Cu data greatly expands the range of known Cu isotopic compositions for basalts, with values ranging from -0.84‰ to +2.61‰. These values overlap with the δ⁶⁵Cu of regional ores, further suggesting a link between the source(s) of the ores and the NGB rocks. The range of δ⁶⁵Cu values also overlaps with mantle rock values, suggesting that the Cu isotopic composition may be a signature derived from the mantle source. Fractionation mechanisms that cause such a broad range in Cu isotopes are still unclear but liquid-vapor transitions and mantle metasomatism are being explored. Furthermore, δ⁶⁵Cu values of international rock standards reported in this study did not agree with previously reported data (Archer and Vance, 2004; Bigalke et al., 2010; Moeller et al., 2012; Liu et al., 2014, 2015) suggesting that aquaregia leach may not be a preferable technique when analyzing volcanic rocks.
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Uma coisa desse mundo : auto-organiza??o, neuroplasticidade e epig?nese da consci?nciaBorges, Charles Irapuan Ferreira 28 March 2017 (has links)
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Previous issue date: 2017-03-28 / This study presents the thesis I have been calling ?epigenesis of consciousness?. The main
problem addressed here is how to account for a strictly materialist explanation of consciousness
without resorting to an unrestricted attachment to any sort of reductive materialism and
determinist naturalism. My working hypothesis takes as its starting point the Spinozist monism
to state: 1. that consciousness emerges from the self-organizing matter; 2. that this
self-organization follows a pattern, a layered formation which runs from the peripheral nervous
system to the neocortex; 3. that this process is related to the neuroplasticity of the brain tissue
and can be mapped by dynamic systems theory. Starting from this hypothesis, I apply the
neurodynamics of emotions to map the three stages behind the uprising of consciousness: 1. the
live present; 2. Memory; 3. Thought. The aim of this work is to state that consciousness is an
evolutionary, co-emergent, subject-to-variation process, merging determinism and freedom in
nature. / O presente trabalho tem a pretens?o de defender a tese que venho chamando de epig?nese da
consci?ncia. O principal problema abordado aqui ? como apresentar uma leitura estritamente
materialista das condi??es de emerg?ncia consci?ncia sem apelar para uma vincula??o irrestrita
ao reducionismo e ao determinismo. Minha hip?tese de trabalho toma como ponto de partida o
monismo espinosista para afirmar: 1. que a consci?ncia emerge da auto-organiza??o material;
2. que esta auto-organiza??o obedece um padr?o, uma forma??o em camadas, que vai do
sistema nervoso perif?rico ao neoc?rtex cerebral; 3. que essa forma??o envolve a
neuroplasticidade e pode ser mapeada pela teoria dos sistemas din?micos. Partindo dessa
hip?tese, aplico os conceitos da neurodin?mica das emo??es para mapear as tr?s etapas da
forma??o da consci?ncia, as tr?s s?nteses passivas: 1. presente vivo; 2. mem?ria; 3. pensamento.
O objetivo do presente trabalho ? fundamentar a tese segundo a qual a forma??o da consci?ncia
? um processo evolutivo, coemergente e sujeito ? varia??o. Com isso, pretendo sustentar uma
vis?o de ag?ncia que prop?e que entendamos como n?o mutuamente excludentes determinismo
e liberdade, na natureza.
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Desenvolvimento e prote??o social na Am?rica Latina : a dial?tica das recomenda??es das ag?ncias multilaterais para a regi?oTeles, Heloisa 21 March 2018 (has links)
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Previous issue date: 2018-03-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / El presente estudio versa sobre las pol?ticas de desarrollo y protecci?n social en Am?rica Latina buscando analizar los presupuestos e influencias que las recomendaciones de las agencias multilaterales ejercen en su conformaci?n. Para ello, fueron problematizadas las concepciones te?ricas y principales tendencias que orientan el desarrollo y la protecci?n latinoamericana, el papel atribuido al Estado en el capitalismo de la Regi?n y las formas de protecci?n social derivadas. El m?todo que paut? el estudio fue el materialismo hist?rico dial?ctico, ya que viabiliza condiciones de an?lisis cr?tico de las causalidades explicativas de la realidad social. La metodolog?a estuvo basada en el abordaje cuantitativo, teniendo como intervalo temporal el per?odo de 1990 a 2017 y espacio geogr?fico a Am?rica Latina. El levantamiento de datos incluy? revisi?n bibliogr?fica e investigaci?n documental de procedencia nacional e internacional. Para el proceso de organizaci?n y an?lisis de los datos se utiliz? la t?cnica de an?lisis de contenido. La investigaci?n trat? de distintas realidades buscando identificar particularidades socio hist?ricas que pudieran evidenciar caracter?sticas comunes entre los pa?ses y en las recomendaciones de las agencias internacionales para la regi?n. En ese aspecto, se identific? que la estructura b?sica de las econom?as y Estados latinoamericanos se encuentra atravesada por la dependencia y subdesarrollo en relaci?n a los pa?ses centrales y que ese cuadro produce altos niveles de explotaci?n, pobreza y desigualdad. En vista de ello, numerosas recomendaciones han sido formuladas por agencias multilaterales con el fin de superar las graves expresiones de la cuesti?n social que se intensifican y fomentar la condici?n de desarrollo con ?nfasis en la integraci?n regional y la prosperidad. Sin embargo, confirmando la tesis difundida en el estudio, las medidas adoptadas por los pa?ses latinoamericanos acabaron agravando a?n m?s el cuadro de dependencia y subordinaci?n, reproduciendo las caracter?sticas hist?rico-sociales conformadoras de la regi?n. Por ?ltimo, se pretendi? poner en pauta la necesidad de analizar las perspectivas para el desarrollo de protecci?n social en Am?rica Latina desde el punto de vista estructural, con el fin de proponer alternativas que puedan efectivamente superar el car?cter dependiente y subordinado de la regi?n en relaci?n a las regiones econ?micas centrales. / O presente estudo versa sobre as pol?ticas de desenvolvimento e prote??o social na Am?rica
Latina buscando analisar os pressupostos e influ?ncias que as recomenda??es das ag?ncias
multilaterais exercem em sua conforma??o. Para tanto, foram problematizadas as concep??es
te?ricas e principais tend?ncias que orientam o desenvolvimento e a prote??o latino-americana,
o papel atribu?do ao Estado no capitalismo da Regi?o e as formas de prote??o social derivadas.
O m?todo que pautou o estudo foi o materialismo hist?rico dial?tico, uma vez que viabiliza
condi??es de an?lise cr?tica das causalidades explicativas da realidade social. A metodologia
esteve alicer?ada na abordagem quanti-qualitativa, tendo como intervalo temporal o per?odo de
1990 a 2017 e espa?o geogr?fico a Am?rica Latina. O levantamento de dados incluiu revis?o
bibliogr?fica e pesquisa documental de proced?ncia nacional e internacional. Para o processo
de organiza??o e an?lise dos dados foi utilizada a t?cnica de an?lise de conte?do. A pesquisa
tratou de distintas realidades buscando identificar particularidades s?cio hist?ricas que
pudessem evidenciar caracter?sticas comuns entre os pa?ses e nas recomenda??es das ag?ncias
internacionais para a regi?o. Sob esse aspecto, identificou-se que a estrutura b?sica das
economias e Estados latino-americanos se encontra perpassada pela depend?ncia e
subdesenvolvimento em rela??o aos pa?ses centrais e que esse quadro produz altos n?veis de
explora??o, pobreza e desigualdade. Diante disso, in?meras recomenda??es foram formuladas
por ag?ncias multilaterais no intuito de superar as graves express?es da quest?o social que se
intensificam e fomentar a condi??o de desenvolvimento com ?nfase para a integra??o regional
e prosperidade. No entanto, confirmando a tese veiculada no estudo, as medidas adotadas pelos
pa?ses latino-americanos acabaram agravando ainda mais o quadro de depend?ncia e
subordina??o, reproduzindo as caracter?sticas hist?rico-sociais conformadoras da regi?o. Por
fim, pretendeu-se colocar em pauta a necessidade de analisar as perspectivas para o
desenvolvimento de prote??o social na Am?rica Latina sob o ponto de vista estrutural, no intuito
de propor alternativas que possam efetivamente superar o car?ter dependente e subordinado da
regi?o em rela??o ?s econ?micas centrais.
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Ormosils fotoativos com fosfotungstato dopados com nanopartículas SiO2@TiO2 e NP de Ag: avaliação fotocrômica e potencial de inibição bactericida frente às bactérias Staphylococcus aureus e Pseudomona aeruginosa / Photoactive ormosil-phosphotungstate materials doped with SiO2@TiO2 and Ag nanoparticles: evaluation of their photochromic response and bacteriainhibition activity against Staphylococcus aureus and Pseudomonas aeruginosaGonçalves, Lidiane Patricia 13 April 2015 (has links)
Neste trabalho foram preparados materiais híbridos do tipo silicatos organicamente modificados (Ormosils) contendo fosfotungstato, [PW12O40]-3 e dopados com nanopartículas sintetizadas core@shell SiO2@TiO2. Os objetivos a serem atingidos com estes materiais são obter filmes com alta sensibilidade à radiação UV e capazes de fotossintetizar nanopartículas de Ag no seu interior e superfície visando revestimentos antibacterianos. O pigmento fotocrômico nos filmes é o fosfotungstato e o core@shell irá atuar como agente potencializador da resposta fotocrômica dele. Dessa maneira variou-se a quantidade de volume da suspensão das partículas core@shell tentando maximizar a resposta fotocrômica com a menor quantidade possível de partículas adicionadas. Observa-se uma resposta não linear da sensibilidade ao UV observada pelo aumento no fotocromismo com a quantidade de suspensão de partículas adicionada. Ormosils com nanopartículas de Ag fotossintetizadas foram preparados com intuito de verificar a inibição desses na formação de biofilmes de bactérias patogênicas, ou seja, Staphylococcus aureus e Pseudomona aeruginosa. Os materiais foram caracterizados por espectroscopias vibracionais, espectroscopia de fotoelétrons de raios X (XPS), Difração de Raios X (DRX), Fluorescência de Raios X, Microscopia de Força Atômica(AFM) e Microscopia Eletrônica de Varredura (MEV). Nos testes de inibição da formação de biofilme notou-se uma maior inibição frente às bactérias S. aureus usando filmes de ormosils core@shell. Entretanto, para a inibição de P. aeruginosa a presença de core@shell não de maneira significativa. Na presença de NP de Ag ambas as bactérias foram inibidas totalmente. Os testes microbiológicos foram caracterizados através de contagem de placa, microscopia de Epifluorescencia, teste de reaproveitamento, teste do halo de crescimento, Microscopia Eletrônica de Varredura e espectroscopia de fotoelétrons de raios X (XPS). / In this project, hybrid materials based on organo modiefied silicates (Ormosils) containing phosphotunsgtic acid (HPW) and doped with SiO2@TiO2 core@shell nanoparticles were prepared. The objectives of the project was to obtain films of these hybrid ormosil-HPW-SiO2@TiO2 materials with high sensitivity to UV radiation and, which after coating with silver nanoparticles, could be used for antibacterial applications. The HPW in these films serves as the photochromic component while the role of SiO2@TiO2 particles was to enhance the innate phototromic reponse of the HPW. The prepared hybrid materials and hybrid films were characterized by vibrational spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction analysis, X-ray fluoresence, atomic force microscopy and scanning electron microscopy. The effect of addition of SiO2@TiO2 particles on the photochromic reponse was systematically studied in order to obtain films with maximum photochromic response. The UV sensitity or the photochromic response showed a non-linear increase as function of the amount of SiO2@TiO2 particles added. The hybrid ormosil-HPW-SiO2@TiO2 films modified with silver nanoparticles were studied for their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa as model bacteria. The ormosil-HPW-SiO2@TiO2 films showed a good degree of inhibition against S. aureus, while the presence of SiO2@TiO2 in the ormosil-HPW films had no significant effect on the inhibition ability of the hybrid films against P. aeruginosa. The ormosil-HPW-SiO2@TiO2 films modified with Ag totally inhibited the growth of both the model bacteria studied. These photochromic and antibacterial hybrid films can find useful applications in UV-sensing devices and antibacterial coatings.
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Determinação da estrutura de uma série de tri(hidroximetil) amino metano complexados com íons metálicos (Cu, Ag, Ni, Zn) / X-ray crystal structures of Cu, Ag, Ni and Zn íons with tri(hidroximetil) amino methaneSilva, Lenilda Austrilino 05 December 1986 (has links)
As estruturas do tri(hidroximetil) amino metano complexado com cobre Cu(II), Cu[NH2C(COH3)3]2+H2O e do tri(hidroximetil)amino metano dopado com prata Ag(I), Ag[NH2C(COH3)3] foram determinados por difração de raios-x. O complexo contendo íons de cobre refinou até um R de 0.034 e foram encontradas as seguintes características principais: sistema cristalino monoclínico; grupo espacial C2/c, a=12.955(2)Å b=10.793(1)Å c=10.091(2)Å β=116.62° V=1261.3(6)޵ Z=4; xDc=1.694(2)g/cm-3; λ(KαMo)=0.71073Å das reflexões medidas 1441 tinham I> 3δ (I). O íon de cobre está coordenado por pares de átomos de oxigênio e nitrogênio os quais formam uma pirâmide de base quadrada, o oxigênio da molécula de água ocupa o outro vértice da pirâmide. A determinação dessa estrutura é utilizada na interpretação da formação de complexos de cobre com tri(hidroximetil) amino metano em função do pH. A estrutura do tri(hidroximetil) amino metano dopado com prata apresentou as seguintes características: sistema cristalino ortorrômbico; grupo espacial Pna21; a=7.800(2)Å b=8.810(3)Å c=8.850(2)Å V=608.85(4)޵ Dc=1.329g/cm-3; Dm=1.337g/cm-3; 435 reflexões com I> 3δ (I); R=0.13; o carbono central é coordenado tetraedricamente por três átomos de carbono do tri(hidroximetil) e um nitrogênio do grupo amino. As estruturas do tris dopado com níquel, e do tris dopado com zinco apresentam-se isomorfa com a estrutura do tris dopado com prata. / The crystal structures of the tri(hydroxymethyl) amine methane complexed with cooper Cu[NH2C(COH3)3]2+H2O and the silver Ag[NH2C(COH3)3] doped into the tri(hydroxymethyl) amine methane have been determined by x-ray diffraction. The complex involving Cu++ refined to final R-factor of 0.034, and the following main features were found: the crystal system is monoclinic and its space group is C2/c, a=12.955(2)Å b=10.793(1)Å c=10.091(2)Å β=116.62° V=1261.3(6)޵ Z=4; Dc=1.694(2)g/cm-3; λ(KαMo)=0.71073Å from measures done, 1441 had I> 3δ (I). The Cu++ is coordinated by couples of atoms of oxygen and nytrogen, which form a base of a quadrangular pyramid, the pyramid vertex is formed by the oxygen of the water molecule. The determination of this structure is used to interpret the rise of tri(hydroxymethyl) amine methane and complexed with Cooper varying the pH. The silver doped into the structures of tris(hydroxymethyl) amine methane presented the following features: crystal system is orthorrombic; space group is Pna21; a=7.800(2)Å b=8.810(3)Å c=8.850(2)Å V=608.85(4)޵ Dc=1.329 g/cm-3; Dm=1.337 g/cm-3; R=0.13; 435 reflections with I> 3δ (I) the central carbon is coordinated tetrahedrally by three atoms of carbon from tri(hydroxymethyl) and a nitrogen from the amine group.
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Metal and oxide nanoparticles : green biosynthesis using Portobello Mushroom Spores (PMS) for nanocomposites and replicas, properties and applicationsAl-Timimi, Iman Abdullah Jaaffer January 2018 (has links)
This thesis describes novel research using Portobello mushroom spores (PMS) as a biotemplate and reducing agent that may be used to produce nanocomposites and replicas with societal benefits. First, the use of PMS as a green eco-friendly bioreagent for the biosynthesis of Ag, Au and TiOx nanoparticles (NPs) and their hybrids is described. These have been characterised using SEM, TEM, XRD, FTIR, UV, SIMS, DLS and TGA (where a full list of acronyms is to be found on page iv). The spherical shape, location and mean diameter of the PMS-held (5-30nm) Ag and Au NPs were confirmed. PMS functional groups are comparable with those in plant sources and allow them to act as reducing/capping/stabilising agents. Second, the sequential biosynthesis of PMS-held Ca2+, CaCO3 and nanohydroxyapatite (nHAp) is described where surface nucleation and growth are facilitated by biotemplate surface hydrophilic polar groups (-OH and -COO-). XRD and HRTEM suggest that the nHAp so formed has lower crystallinity and greater directed growth in the (002) direction than commercial nHAp (e.g. Bio-Oss), making PMS-routes useful for the delivery of artificial bone (after subsequent PMS removal). Furthermore, PMS-held nHAp showed more rapid in-vitro mineralization in simulated body fluid (SBF). Third, it is shown that ascorbic acid (AA), haemoglobin (Hb) and insulin (In) can be loaded into/released by PMS through its cell walls faster than with synthetic hydrogels (PVA); the transdermal use of PMS nanocomposites is considered in the context of drug delivery nanotechnology, avoiding size-dependent toxicity. Fourth, it is shown by traditional diffusion and novel methods that the antimicrobial activity especially of Ag/PMS, but also TiOx/PMS and Ag-TiOx/PMS (but not Au/PMS) is good in the inhibition of the growth of E.coli and S.aureus bacteria. The highest activity of Ag/PMS is attributed to Agx+ release. Fifth, the synthesis of NPs/PMS and biomimetic TiOx/PMS has shown to lead to good photocatalysis for the removal of coloured organic pollutants (e.g. methyl orange) from water, with faster rates of removal in molecules/mg/s and turnover numbers (TON) (s-1) than commercial anatase-rutile TiO2 (P25) possibly as the texture of the titania replicas raises the number of multiple reflections of light.
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