Catalisadores de Ni suportado em La2O3, SiO2 e La2O3-SiO2 (com teores mássicos de La2O30 de 10%, 30% e 50%) tiveram seu desempenho avaliado frente a reação de reforma a vapor de glicerol. O efeito do suporte sobre a atividade, estabilidade e seletividade do catalisador foi avaliado, assim como diferentes métodos de preparo, teores de Ni e temperaturas de reação. Os catalisadores foram preparados pelos métodos da impregnação úmida seqüencial, impregnação úmida simultânea, impregnação sobre o suporte precipitado e co-precipitação, utilizando teores mássicos de 5%, 10% e 15% de Ni. Foram utilizadas as seguintes técnicas de caracterização: espectroscopia de energia dispersiva de raios X, fisissorção de nitrogênio, difratometria de raios X, redução a temperatura programada e difração de raios X in situ. Os catalisadores foram testados por um período de 5h, a fim de verificar a atividade e seletividade para a reação de reforma a vapor de glicerol a 500°C, 600°C e 700°C, e as propriedades dos catalisadores foram correlacionadas com os resultados obtidos dos ensaios catalíticos. Após as reações, os catalisadores foram submetidos as seguintes análises: análise elementar, difratometria de raios X e microscopia eletrônica de varredura. Foi observado que o Ni interage de forma variada com os diferentes suportes, que o método de preparação utilizado influencia propriedades dos catalisadores e que, dependendo do teor mássico de Ni suportado, o catalisador pode ser mais ou menos ativo para a reação de reforma a vapor de glicerol. Observou-se também que a temperatura influencia no desempenho da reação, sendo que os melhores resultados foram obtidos a 600°C com o catalisador 15Ni30LaSi preparado por impregnação úmida simultânea, que foi testado também por 20h para que fosse analisada sua estabilidade em um maior intervalo de tempo. / Ni catalysts supported on La2O3, SiO2 and La2O3-SiO2 (with 10%, 30% and 50%wt.La2O3) were evaluated in the glycerol steam reforming reaction. The effect of the supports was analyzed on the catalysts activity; stability and selectivity as well as different methods of preparation, Ni contents and reaction temperatures. Catalysts were prepared by the sequential wet impregnation, simultaneous wet impregnation, impregnation of Ni on support precipitate and co-precipitation methods using 5%, 10% and 15%wt.Ni. The catalysts were characterized by energy dispersive X-ray spectroscopy, nitrogen physisorption, X-ray diffraction, temperature programmed reduction and X-ray diffraction in situ. The catalytic tests were performed during 5 hours in order to verify the activity and selectivity for the glycerol steam reforming at 500°C, 600°C and 700°C, and identify the relationship between the catalysts properties and the results obtained with the catalytic tests. After the reactions, the catalysts were characterized by elemental analysis, X-ray diffraction and scanning electron microscopy. It was observed that the Ni interacted variously with different supports; the preparation method used influenced on the catalysts properties and, depending on the Ni content, the catalyst was more or less active for the glycerol steam reforming. It was also observed that the temperature of reaction influenced on the reaction performance, and the best results were obtained at 600°C with the 15Ni30LaSi catalyst, prepared by simultaneous wet impregnation, which was also tested for 20 hours to analyze its stability in a longer period.

Catalisadores de Ni suportados em carbono foram sintetizados por diferentes rotas e avaliados frente a oxidação de glicerol em meio alcalino. O método de impregnação química, seguido de um tratamento térmico em uma atmosfera redutora de H2 por 2 horas, foi escolhido por fornecer um material mais ativo, e através deste método materiais como CoNi, FeNi, FeCoNi contendo 20% de metal foram sintetizados. As amostras foram caracterizadas por Análise Termogravimétrica (TGA-DTA) e Difração de Raios X (XRD) para verificar a quantidade de metal e tamanho de cristalito médio, respectivamente. Ensaios eletroquímicos de Voltametria Cíclica (CV) foram realizados para avaliar a atividade eletroquímica dos catalisadores frente a reação de oxidação do glicerol. Os resultados demonstram que a espécie oxihidróxido de níquel β-NiOOH foi a espécie catalítica ativa frente a oxidação de glicerol em meio alcalino. Como a formação de oxihidróxidos de cobalto e ferro ocorrem em potenciais mais baixos que o níquel, estes elementos adicionaram mudanças no perfil observado para o Ni/C. Estudos em condições controladas também foram feitos através de Voltametria Cíclica. O processo de oxidação do glicerol foi influenciado pela velocidade de varredura, temperatura e concentração do NaOH e glicerol. A relação linear entre a corrente de pico e a raiz quadrada da velocidade de varredura corresponde a um processo controlado por difusão. Verificou-se que ambos os Ipico e Epico são fortemente dependentes da concentração do glicerol. Em um potencial selecionado, experimentos de cronoamperometria foram realizados e os produtos de reação analisados por cromatografia líquida de alta eficiência (HPLC). A conversão do glicerol bem como a seletividade dos produtos formados depende da composição do catalisador. A distribuição de produtos foi correlacionada com os dados de espectroscopia de infravermelho (FTIR), os quais suportam o mecanismo de reação proposto. / Carbon supported nickel nanomaterials were synthesized by different routes and evaluated toward the oxidative transformation of glycerol in alkaline medium. The impregnation method, followed by heat-treatment in reducing H2 atmosphere for 2 hours, was chosen by providing a more active material. This method was used to prepare catalysts with metal loadings of 20 wt. %, such as CoNi/C, FeNi/C and FeCoNi/C. Physical characterizations of the materials were performed by using Thermogravimetric Analysis-Differential Thermal Analysis (TGA-DTA) and X-Ray Diffraction (XRD) to determine their metallic load and the crystallite size, respectively. Cyclic voltammetry was mainly used to evaluate the electrochemical activity of the catalysts for glycerol oxidation reaction. The results demonstrated that nickel oxyhydroxide, β-NiOOH, is the active catalytic specie for the glycerol oxidation reaction in alkaline medium. Since the formation of cobalt and iron oxy-hydroxides occurs at lower potentials than those of nickel, amounts of cobalt and iron were added to modify the Ni material. Studies under several well defined experimental conditions were performed by Cyclic Voltammetry. The process of glycerol oxidation was influenced by the scan rate, temperature, glycerol and NaOH concentration. The linear relationship between the peak current density and square root of scan rate corresponds to a diffusion-controlled process for glycerol oxidation on Ni/C. It was found that both the Ipeak and Epeak are strongly depending on the glycerol concentration. In a selected potential chronoamperometry experiments were carried out and the glycerol oxidation products on the Ni-based anodes were analyzed by High-Performance Liquid Chromatography (HPLC). The glycerol conversion depends on the catalyst composition and the distribution. The products were correlated with those identified by infrared reflectance spectroscopy, which supported the simplified mechanism proposed.

A glicerina, na alimentação, pode ser considerada uma boa fonte energética. Assim, sua utilização como substituta em parte de grãos e outros alimentos ricos em amido é amplamente estuda já que esses alimentos podem causar alterações metabólicas e digestivas quando em alto consumo. Neste estudo, objetivou-se comparar níveis de adição de glicerina na dieta de equinos. Foram utilizados oito pôneis machos, castrados, da raça Mini-Horse, com idade aproximada de 9 anos ± 6 meses, peso corporal médio de 149,80 ± 17,20 kg e escore corporal médio de 5,4 ± 0,7. Os animais foram alojados em baias individuais. Adotou-se consumo diário individual de 1,75% do peso corporal (PC), sendo 1% do PC em matéria seca (MS) proveniente do volumoso e 0,75% do PC em MS do concentrado, com proporção 60:40 (volumoso:concentrado). O delineamento experimental utilizado foi o quadrado latino duplo 4 x 4 contemporâneos. As dietas diferiram quanto ao nível de inclusão de glicerina (0, 4, 8 e 12%) que foram calculados com relação á porcentagem de concentrado fornecidos por animal. As avaliações foram realizada em quatro períodos, sendo 14 dias de adaptação à dieta, 5 dias de coleta total de fezes (CTF) e 2 semanas de intervalo entre os períodos. Avaliou-se a digestibilidade aparente total dos nutrientes e fermentabilidade da glicerina a partir da CTF, por meio das análises de respostas glicêmicas, insulinêmicas, ácido graxos da cadeia curta, ácidos graxos não esterificados (NEFA) e pH das fezes. Também foram realizadas análises de segurança e aceitabilidade que se constituiu de análises de função hepática e renal, triglicerídeos, colesterol e frações além da avaliação do comportamento alimentar dos animais. Além de análise de implicações econômica a partir da simulação de substituição do milho pela glicerina bruta. Os dados foram submetidos à análise pelo programa Statistical Analysis System (SAS Institute Inc., 2010). Para os resultados significativos, foi utilizado o teste de Tukey com P<0,05. Não houve diferenças entre os tratamentos em nenhuma das análises realizadas (P<0,05). A glicerina se mostrou palatável e com aceitabilidade. A substituição de milho por glicerina, mesmo em valores de 1%, representa economicamente 0,42% de ganho. A suplementação de glicerina bruta na dieta de equinos se apresenta como segura não afetando o comportamento alimentar, a higidez e a saúde digestiva dos animais, possuindo justificativa econômica para uso. / Glycerin in food can be considered a good source of energy. Thus, its use as a substitute part of grains and other starchy foods is widely studied since these foods can cause metabolic and digestive changes when in high consumption. The objective of this study was to compare levels of glycerin addition in the equine diet. Eight male, castrated Mini-Horse male ponies, aged approximately 9 years ± 6 months, mean body weight of 149.80 ± 17.20 kg and mean body score of 5.4 ± 0.7 were used. The animals were housed in individual stalls. Individual daily consumption of 1.75% of body weight (CP) was used, with 1% CP in dry matter (DM) from bulky and 0.75% CP in DM from concentrate, with a ratio of 60:40 voluminous: concentrate). The experimental design used was the contemporary 4 x 4 double Latin square. The diets differed in the glycerin inclusion levels (0, 4, 8 and 12%) that were calculated in relation to the percentage of concentrate supplied per animal. The evaluations were performed in four periods, 14 days of adaptation to the diet, 5 days of total collection of feces (TCF) and 2 weeks of interval between periods. The total apparent digestibility of nutrients and fermentability of glycerol from the TCF were evaluated through glycemic, insulinemic, short chain fatty acid, non-esterified fatty acid (NEFA) and faecal pH analyzes. Safety and acceptability analyzes were also performed, which consisted of analyzes of liver and renal function, triglycerides, cholesterol and fractions, besides the evaluation of the animals\' feeding behavior. In addition to analysis of economic implications from the simulation of substitution of corn by crude glycerin. The data were submitted to analysis by the Statistical Analysis System (SAS Institute Inc., 2010). For the significant results, the Tukey test was used with P <0.05. There were no differences between treatments in any of the analyzes performed (P <0.05). Glycerin was palatable and acceptable. The substitution of corn for glycerin, even at 1%, represents economically 0.42% gain. The supplementation of crude glycerin in the equine diet presents itself as safe, without affecting the alimentary behavior, the hygiene and the digestive health of the animals, with economic justification for use.

Submitted by Biblioteca da Faculdade de Farmácia (bff@ndc.uff.br) on 2017-04-19T16:57:00Z No. of bitstreams: 1 Pontes, Simone Gomes [Dissertação, 2012].pdf: 1302242 bytes, checksum: 7aab3cecd1b771d41f103c491d846579 (MD5) / Made available in DSpace on 2017-04-19T16:57:00Z (GMT). No. of bitstreams: 1 Pontes, Simone Gomes [Dissertação, 2012].pdf: 1302242 bytes, checksum: 7aab3cecd1b771d41f103c491d846579 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A dihidroxiacetona (DHA) é uma molécula constituída por três carbonos e não tóxica, utilizada como insumo para as indústrias de cosméticos, fármacos e química fina. É produzida industrialmente por fermentação, utilizando a bactéria Gluconobacter oxydans. Esse processo tem como principal limitação a inibição do crescimento tanto pelo substrato – glicerol – quanto pelo produto – DHA e, por tal, estudos recentes descrevem propostas para melhoria do processo. Sendo a conversão de glicerol a DHA realizada por uma única enzima em uma etapa, o presente trabalho considera que tal processo se enquadra nas definições de uma biotransformação, ou seja, a utilização de um catalisador biológico com o propósito de converter um substrato a um produto estruturalmente similar, através de modificações específicas e utilizando um número limitado de etapas enzimáticas. Dessa forma, neste estudo foram avaliados comparativamente a secagem de células em acetona e, em um segundo momento, a utilização de células de Gluconobacter oxydans previamente crescidas, para a produção de DHA a partir de glicerol. Objetivando contornar o principal problema do processo, que é a inibição do crescimento microbiano pelo substrato e pelo produto, foram testadas duas linhagens. A utilização de células secas em acetona se mostrou possível, porém os resultados não foram reprodutíveis e células previamente crescidas por 24 horas passaram a ser usadas nos experimentos de biotransformação. O pH e a temperatura de reação foram selecionados a partir de um planejamento delineamento composto central rotacional como sendo de 34ºC e pH de 4,5, para G. oxydans CCT 0552 e de 26ºC e pH de 4,5 para G. oxydans CCT 0174. A linhagem G. oxydans CCT 0552 se mostrou mais adequada à oxidação de glicerol à DHA, com aumento do acúmulo de DHA no meio reacional com o tempo (2,1 g/g biomassa) e com a produtividade constante (0,45 g/g biomassa). Foi constatada perda de atividade nas células estocadas por congelamento, o que leva à necessidade de selecionar um melhor método de conservação das células para a utilização na produção / The dihydroxyacetone (DHA) is a non-toxic molecule consisting of three carbons, used in the cosmetics, pharmaceuticals and fine chemicals industry. The DHA is industrially produced by fermentation, using the bacteria Gluconobacter oxydans. The main bottleneck of this process is the growth inhibition by the substrate – glycerol – and the product – DHA. This problem leads recent studies to describe proposals for improving the process. As the conversion of glycerol to DHA is performed by a single enzyme in one step, this study considers that this process fits in the definitions of biotransformation, in other words, the use of a biological catalyst in order to convert a substrate for a structurally similar products, by speficic modifications, and using a limited number of enzymatic steps. Thus, this study were assessed by comparison with drying of cells in acetone and in second stage, the use of previously grown cells of Gluconobacter oxydans for the production of DHA from glycerol. The use of dried cells proved to be possible, but the results were not reproducible and the biotransformation experiments were done with previously grown cells of 24 hours age. . The best pH and temperature for the reaction were selected from a central composite design as being 34o C and pH 4.5 for G. oxydans CCT 0552 and 26o C and pH 4.5 for G. oxydans CCT 0174. The strain G. oxydans CCT 0552 was more suitable for the oxidation of glycerol to DHA, with increased accumulation of DHA in the reaction media (2,1 g/g biomass) and constant productivity (0,45 g/g biomass). Loss of activity was observed in cells stored by freezing, which leads to the need to select a best method of preserving cells for the production

Doctor of Philosophy / Department of Animal Sciences and Industry / Robert D. Goodband / Two experiments evaluated effects of glycerol on pellet mill production and pig performance. In Exp. 1, increasing glycerol increased (quadratic; P < 0.01) pellet durability index through 9% added glycerol. Adding glycerol decreased (linear; P > 0.01) production energy (kWh/t). In Exp. 2, pigs were fed one of seven diets with no added soy oil or glycerol (control); the control diet with 3 or 6% added soy oil, 3 or 6% added glycerol, and 6 or 12% additions of a 50:50 soy oil/glycerol blend in a 26-d growth assay. Adding glycerol improved (P < 0.01) pellet durability compared to soy oil and the soy oil/glycerol blend treatments. Pigs fed glycerol had increased (linear, P < 0.03) ADG. Adding soy oil, glycerol, or the soy oil/glycerol blend resulted in similar final BW. Two experiments evaluated the effects of glycerol as a replacement for lactose on pellet mill production and nursery pig performance. In Exp. 1, pigs were fed one of ten treatments that included 0, 3.6, or 7.2% lactose or 0, 3.6, or 7.2 % glycerol and fed in either meal or pelleted form. Pellet durability index increased (linear; P < 0.01) with added lactose and glycerol. Glycerol decreased (linear; P < 0.01) production energy (kWh/t). There was a tendency (P < 0.06) for an inclusion level × diet form (meal or pellet) interaction observed for ADG. Pigs fed the pelleted diets containing the 7.2% glycerol inclusion had decreased ADG compared to all other treatments. In Exp. 2, pigs were fed one of fourteen diets that included 0, 3.6, 7.2, or 10.8% lactose or 0, 3.6, 7.2, or 10.8 % glycerol and fed in either meal or pelleted form. There was no effect (P < 0.27) of diet form, inclusion level, or source on ADG or ADFI. Eight experiments evaluated the effect of ingredients on the flow ability of ground corn. Flow ability of feed improved with added glycerol, especially when added to meal diets containing hammer mill ground corn. Specialty protein ingredients in powder form reduce flow ability, while fine lactose sources improved flow ability. Granulated ingredients improved flow ability.

Depuis plusieurs années, notre équipe de recherche s'intéresse au développement de nouvelles familles de dendrimères utilisant des dérivés bio sourcés (pentoses, glycérol ou dérivés correspondants) dont la valorisation est un sujet de recherche d'intérêt de notre région. Ainsi, certains glyco- ou glycérodendrimères dérivés de PPIs (polypropylène imines) ont déjà été obtenus et valorisés dans plusieurs domaines. Cette thèse présente la synthèse et la caractérisation de nouveaux dendrimères dérivés du glycérol. Leur efficacité dans des processus catalytiques et d'encapsulation de molécules d'intérêt a également été démontrée.Dans un premier temps, deux nouvelles familles de dendrimères directement constitués de glycérol en tant que brique élémentaire ont été synthétisées : l'une via des réactions de « click chemistry » pour obtenir des glycéroclickdendrimères, et l'autre via des réactions successives d'allylation et d'oxydation pour obtenir des glycéroladendrimères.Dans un second temps, la fonctionnalisation de dendrimères PAMAMs par du carbonate de glycérol a été effectuée par synthèse « classique » ou assistée par micro-ondes. L'efficacité de ces glycérodendrimères ainsi obtenus (en comparaison avec des glycérodendrimères dérivés de PPIs) a été évaluée : tout d'abord, pour la stabilisation de nanoparticules de platine utilisées en catalyse d'hydrogénation de cétones α,β-insaturées en milieu aqueux, puis, pour l'encapsulation de molécules organiques d'intérêt. Pour finir, une première approche de dynamique moléculaire a été réalisée afin de déterminer les propriétés structurales de deux glycérodendrimères issus de la réaction de couplage entre le carbonate de glycérol et un PAMAM ou un PPI. / Since a few years, our team is interested in developing dendrimers using different biosourced derivatives (pentoses, glycerol or derivatives) whose valuation is a prime research topic within our region. Some glyco- or glycerodendrimers derivate from PPIs (polypropylenimines) were already obtained and valued in several domains. This thesis presents the synthesis and the characterization of new glycerol-based dendrimers. Their efficiency in catalytic processes or for the encapsulation of molecules of interest was also demonstrated. First, two new families of dendrimers directly constituted of glycerol as building block, were synthesized: one via click chemistry reactions to obtain glyceroclickdendrimers, and the other, via successive reactions of allylation and oxidation to obtain glyceroladendrimers. Secondly, the functionalization of PAMAM's dendrimers with glycerol carbonate was carried out either by “classical” or microwave assisted synthesis. The efficiency of these glycerodendrimers (in comparison with PPI-based glycerodendrimers) was evaluated: firstly, for the stabilization of platinum nanoparticles used for the catalysis of hydrogenation of α,β-unsaturated ketones in aqueous media, and then, for the encapsulation of organic molecules of interest. Finally, a first molecular dynamics approach was realized to determine the structural properties of two glycerodendrimers from the coupling reaction between the glycerol carbonate and PAMAM or PPI.

Due to an increased environmental awareness and thus, concerns over the use of fossil-based monomer for polymer production, there is an ongoing effort to find alternatives to non-renewable traditional monomers. This has ushered in the rapid growth in the development of bio-based materials such as green monomers and biodegradable polymers from vegetable and animal resources. Glycerol, as a renewable bio-based monomer, is an interesting candidate for sustainable polymer production. Glycerol is a renewable material that is a by-product of the transesterification of vegetable oils to biodiesel. Utilization of the excess glycerol derived from the growing biodiesel industry is important to oleochemical industries. The main objective of this thesis was to produce high molecular weight polyglycerol from glycerol and synthesize stimuli-responsive polyglycerol hydrogels. The work began with an investigation of the step-growth polymerization of glycerol to relatively high molecular weight polyglycerol using several catalysts. The catalytic reaction mechanisms were compared and the polymer products were fully analyzed. High molecular weight partially branched polyglycerol with multimodal molecular weight distributions was obtained. The polymerization of glycerol proceeded fastest with sulphuric acid as catalyst as indicated by the highest observed conversion of monomer along with the highest molecular weights. Theoretical models were used to predict the gel point and to calculate monomer functionality. High molecular weight polyglycerol was used to synthesize novel stimuli-responsive hydrogels. Real-time monitoring of step-growth polymerization of glycerol was investigated using in-line and off-line Attenuated Total Reflectance/Fourier Transform infrared (ATR-FTIR) technique.

Starch is a natural polymer occurring in the seeds, tubers and stems of many plants, including maize. It is a mixture of two polymers: linear amylose and highly branched amylopectin. The ratio and the molar masses of the two polymers depend on the starch source, giving rise to different starch properties. Thermoplastic starch (TPS) was obtained by gelatinising a dry-blend mixture of maize starch, water, plasticisers and additives in a single-screw laboratory extruder. The TPS formed is a translucent amorphous material that could be shaped into pellets and injection-moulded into a variety of articles, just like conventional plastics [Shogren et al., 1994]. The advantages of TPS are that it is cheap and fully biodegradable. However, because of its hydrophilic nature, its properties and dimensional stability are influenced by moisture (humidity). It is also not easily processed like conventional plastics and the freshly moulded material ages, i.e. its properties change over time. The latter is caused by retrogradational structural changes which include helix formation and the crystallisation that occurs above the glass transition temperature [Myllärinen et al., 2002]. The unacceptable physical and processing properties of TPS were improved by blending with other polymers. The objective of this work was to determine the effects of water and glycerol content and the starch source or type on the mechanical properties of maize-based TPS. In addition, the effect of gypsum filler and polyamides or polyvinyl butyral (PVB) as modifying agent was also investigated. The PVB was based on material recycled from automotive windscreens. As with the thermoplastic starch, the thermoplastic/polymer blends, e.g. polyvinyl butyral, were also prepared using a single-screw extruder. After pelletisation, the materials were conditioned at 30 °C and a relative humidity of 60%. Tensile test specimens were prepared by injection moulding. Samples were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and tensile testing. The effect of environmental conditions (temperature and humidity or water submersion) on the ageing of the samples was investigated using tensile properties as a measure. Initial extrusion and moulding trials revealed that the TPS compounds were very difficult to process. Difficulties were encountered with feeding the dry blends into the compounding extruder. The moulded samples adhered strongly to the mould walls, especially the sprue part. These problems were overcome by adding 2,5% precipitated silica to improve the flowability of the dry blends and stearyl alcohol at ca. 1,5% as a processing aid. The latter performed as an external lubricant and mould-release agent. Nevertheless, for some compositions it was also necessary to use ‘Spray-and-Cook’ as mould-release agent during injection moulding. The results show that HiMaizeTM, a high-amylose maize starch, provided the best properties in TPS and its blends. Further improvements in properties were obtained by blending with low-molecular-weight hot-melt adhesive-grade polyamides (Euremelt 2138 and 2140), engineering polyamide (EMS Grilon CF 62 BSE) or low amounts of PVB. The properties of all the compounds investigated were affected by moisture content and also by ageing. The TPS-PVB blends showed highly non-linear composition-dependence. SEM and DMA revealed a phase separation for all the TPS-PVB blend compositions investigated. The tensile properties were negatively affected by ageing in a high-humidity environment and they deteriorated rapidly when the samples were soaked in water. Synergistic property enhancement was observed for a compound containing 22% thermoplastic starch. It featured a higher tensile strength, showed better water resistance and was significantly less affected by ageing. At higher PVB levels, the property dropped to values that were lower than expected from the linear blending rule. / Thesis (PhD)--University of Pretoria, 2008. / Chemical Engineering / unrestricted

[EN] Cryopreserved boar sperm is not used extensively for artificial insemination due to poor fertility rates of the sperm after freezing and thawing. The sperm membrane is damaged when cooled from body temperature to 5 ºC (cold shock), as well as during the freeze-thaw process. Increasing the cholesterol content of boar sperm membranes could increase their post-thaw survival, similarly to other species that are cold shock sensitive. Cholesterol can be easily added to sperm membranes using cholesterol-loaded cyclodextrins (CLC). Treating sperm from different species susceptible to cold-shock with CLC before cryopreservation improves sperm cryosurvival. Egg yolk and glycerol are common constituents of extenders used for boar sperm cryopreservation. However, conventional freezing extenders could not be the appropriate for CLC-treated sperm. The aim of this Thesis is to evaluate cryosurvival of CLC or cyclodextrin-treated boar sperm in three different conditions: using conventional freezing extenders, using extenders with alternative concentrations of glycerol and egg yolk and using amides as cryoprotectants. CLC or methyl- ß-cyclodextrin treatment (1 mg/120 x 106 sperm) prior to cryopreservation using a conventional freezing extenders provided either slight or no benefit, respectively, to post-thaw sperm plasma membrane integrity (+ 8%; P < 0.05) and motility (P > 0.05). In addition, sperm from both, good and poor freezers, responded similarly to CLC treatment (P > 0.05). Reduction in egg yolk concentration from 20 to 10% was detrimental for post-thaw sperm viability, even in semen treated with CLC (- 12%; P < 0.05). On the other hand, it was observed that traditional concentration of glycerol (3%) was not the appropriate to freeze CLC-treated sperm (- 13% viable sperm compared to control; P < 0.05). Thus, CLC-treated sperm showed a higher tolerance (+ 13 % sperm viability; P < 0.05) to high glycerol concentrations (5%) than non-treated sperm. Regarding the efficacy of amides as cryoprotectants, three of the amides (lactamide, acetamide and formamide) produced deleterious effects in fresh boar sperm (P < 0.05). The other amides (methylformamide, dimethylacetamide and dimethylformamide) efficiently improved post-thaw sperm viability (+ 5 to 15 %; P < 0.05) but negatively affected the sperm motility (- 11 to 16% total motile sperm; P < 0.05) and the sperm fertilizing ability in vitro (dimethylformamide: - 64 % penetration rate; P < 0.05), irrespective of the sperm treatment. On the other hand, CLC-treated samples showed better in vitro fertilizing ability than control samples when glycerol was used as cryoprotectant (+ 2 penetrated spermatozoa/oocyte; P < 0.05). The results obtained in this Thesis suggest that conventional freezing protocols should be optimized for CLC-treated boar sperm in order to obtain the benefit of CLC treatment observed in other species sensitive to cold shock. / [ES] Las inseminaciones artificiales en la especie porcina se realizan habitualmente con semen refrigerado, debido a las bajas tasas de fertilidad obtenidas con el semen congelado-descongelado. La membrana del espermatozoide sufre importantes daños cuando es sometida a la fase de enfriamiento desde la temperatura corporal hasta alcanzar los 5 ºC (choque térmico), así como durante el proceso de congelación y descongelación. El aumento del contenido de colesterol en las membranas de los espermatozoides de cerdo podría mejorar su supervivencia tras la descongelación, como sucede en otras especies sensibles al choque térmico. Este incremento en la cantidad de colesterol se puede realizar fácilmente utilizando ciclodextrinas saturadas de colesterol (CLC). El tratamiento con CLC de espermatozoides de varias especies susceptibles al choque térmico antes de la congelación ha conseguido mejorar su supervivencia tras la descongelación. En los protocolos convencionales de congelación de semen porcino se utilizan habitualmente diluyentes de congelación compuestos por yema de huevo y glicerol, sin embargo, puede que estos diluyentes de congelación convencionales no sean los más apropiados para congelar espermatozoides tratados con CLC. El objetivo de esta Tesis es evaluar la supervivencia a la congelación de los espermatozoides porcinos tratados con CLC o ciclodextrinas utilizando diluyentes de congelación convencionales, utilizando concentraciones alternativas tanto de yema de huevo como de glicerol o utilizando amidas en lugar de glicerol como crioprotectores Utilizando diluyentes convencionales, el tratamiento con 1mg de CLC o de metil-ß-ciclodextrina/120 millones de espermatozoides previamente a la congelación proporcionó una leve mejora de la integridad de la membrana plasmática espermática (+ 8%; P < 0,05) y ningún beneficio sobre la movilidad espermática (P > 0,05). Además, la respuesta al tratamiento con CLC fue similar independientemente de si los espermatozoides procedían de verracos buenos o malos congeladores (P > 0,05). Una reducción de la concentración de yema de huevo de un 20 a un 10% fue perjudicial para la supervivencia de los espermatozoides tras la descongelación, incluidos aquellos que habían sido tratados previamente con CLC (- 12% espermatozoides vivos; P < 0,05). Por otro lado, observamos que las concentraciones de glicerol utilizadas habitualmente (3%) no son las más apropiadas para congelar espermatozoides tratados con CLC (- 13 % viabilidad espermática comparando con las muestras control; P < 0,05), ya que éstos mostraron una mayor tolerancia (+ 13 % espermatozoides vivos; P < 0,05) que las muestras control a las concentraciones de glicerol más altas (5%). Con respecto a la eficacia de las amidas como crioprotectores para semen porcino, tres de las amidas (lactamida, acetamida y formamida) produjeron efectos perjudiciales durante su incubación con semen fresco (P < 0,05). El resto de amidas evaluadas (metilformamida, dimetilacetamida y dimetilformamida) mejoraron eficientemente la viabilidad espermática tras la congelación (+ 5 a 15 %; P < 0,05), sin embargo, afectaron negativamente tanto la movilidad espermática (- 11 a 16% móviles totales; P < 0,05) como la capacidad de fecundación in vitro (dimetilformamida: - 64 % en la tasa de penetración; P < 0,05), independientemente de si el semen fue tratado con CLC o no. Por otro lado, las muestras tratadas con CLC mostraron mejor capacidad de fecundación in vitro que las muestras control cuando se utilizó el glicerol como crioprotector (+ 2 espermatozoides penetrados/ovocito; P < 0,05). Los resultados obtenidos en esta Tesis sugieren que sería necesaria la adecuación de los protocolos de congelación convencionales para congelar semen porcino tratado con CLC con el propósito de alcanzar los claros beneficios obtenidos con dicho tratamiento cuando ha sido evaluado en otras especies sensibles al choque térmico. / [CAT] Les inseminacions artificials en l'espècie porcina es realitzen habitualment amb semen refrigerat, a causa de les baixes taxes de fertilitat obtingudes amb el semen congelat-descongelat. La membrana de l'espermatozoide pateix importants danys quan és sotmesa a la fase de refredament des de la temperatura corporal fins a arribar als 5 ºC (xoc tèrmic), així com durant el procés de congelació i descongelació. L'augment del contingut de colesterol a les membranes dels espermatozoides de porc podria millorar la seva supervivència després de la descongelació, com succeeix en altres espècies sensibles al xoc tèrmic. Aquest increment en la quantitat de colesterol es pot realitzar fàcilment utilitzant ciclodextrines saturades de colesterol (CLC). El tractament amb CLC d'espermatozoides de diverses espècies susceptibles al xoc tèrmic abans de la congelació ha aconseguit millorar la seva supervivència després de la descongelació. En els protocols convencionals de congelació de semen porcí s'utilitzen habitualment diluents de congelació compostos per rovell d'ou i glicerol, però, pot ser que aquests diluents de congelació convencionals no siguin els més apropiats per congelar espermatozoides tractats amb CLC. L'objectiu d'aquesta Tesi és avaluar la supervivència a la congelació dels espermatozoides porcins tractats amb CLC o ciclodextrines utilitzant diluents de congelació convencionals, utilitzant concentracions alternatives tant de rovell d'ou com de glicerol o utilitzant amides en lloc de glicerol com crioprotectors Utilitzant diluents convencionals, el tractament amb 1 mg de CLC o de metil-ß-ciclodextrina / 120 milions d'espermatozoides prèviament a la congelació va proporcionar una lleu millora de la integritat de la membrana plasmàtica espermàtica (+ 8%; P <0,05) i cap benefici sobre la mobilitat espermàtica (P> 0,05). A més, la resposta al tractament amb CLC va ser similar independentment de si els espermatozoides procedien de verros bons o dolents congeladors (P> 0,05). Una reducció de la concentració de rovell d'ou d'un 20 a un 10% va ser perjudicial per a la supervivència dels espermatozoides després de la descongelació, inclosos aquells que havien estat tractats prèviament amb CLC (- el 12% espermatozoides vius; P <0,05) . D'altra banda, observem que les concentracions de glicerol utilitzades habitualment (3%) no són les més apropiades per congelar espermatozoides tractats amb CLC (- 13% viabilitat espermàtica comparant amb les mostres control; P <0,05), ja que aquests van mostrar una major tolerància (+ 13% espermatozoides vius; P <0,05) que les mostres control a les concentracions de glicerol més altes (5%). Pel que fa a l'eficàcia de les amides com crioprotectors per semen porcí, tres de les amides (lactamida, acetamida i formamida) van produir efectes perjudicials durant la seva incubació amb semen fresc (P <0,05). La resta de amides avaluades (metilformamida, dimetilacetamida i dimetilformamida) van millorar eficientment la viabilitat espermàtica després de la congelació (+ 5 a 15%, P <0,05), però, van afectar negativament tant la mobilitat espermàtica (- 11 a 16% mòbils totals; P <0,05) com la capacitat de fecundació in vitro (dimetilformamida: - el 64% en la taxa de penetració; P <0,05), independentment de si el semen va ser tractat amb CLC o no. D'altra banda, les mostres tractades amb CLC van mostrar millor capacitat de fecundació in vitro que les mostres control quan es va utilitzar el glicerol com crioprotector (+ 2 espermatozous penetrats / oòcit; P <0,05). Els resultats obtinguts en aquesta Tesi suggereixen que seria necessària l'adequació dels protocols de congelació convencionals per congelar semen porcí tractat amb CLC amb el propòsit d'assolir els clars beneficis obtinguts amb el tractament quan ha estat avaluat en altres espècies sensibles al xoc tèrmic. / Blanch Torres, E. (2015). Treating boar sperm with cholesterol-loaded cyclodextrins or cyclodextrins prior to cryopreservation: effects on post-thaw in vitro sperm quality of sperm cryopreserved in different freezing extenders [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58773 / TESIS

[EN] The project of this Ph.D. thesis is based on a co-supervised collaboration between Università di Bologna, ALMA MATER STUDIORUM (Italy) and Instituto de Tecnología Química, Universitat Politècnica de València ITQ-UPV (Spain). This Ph.D. thesis is about the synthesis, characterization and catalytic testing of complex mixed-oxide catalysts mainly related to the family of Hexagonal Tungsten Bronzes (HTBs). These materials have been little explored as catalysts, although they have a great potential as multifunctional materials. Their peculiar acid properties can be coupled to other functionalities (e.g. redox sites) by isomorphous substitution of tungsten atoms with other transition metals such as vanadium, niobium and molybdenum. In this PhD thesis, it was demonstrated how it is possible to prepare substituted-HTBs by hydrothermal synthesis; these mixed-oxide were fully characterize by a number of physicochemical techniques such as XPS, HR-TEM, XAS etc. They were also used as catalysts for the one-pot glycerol oxidehydration to acrylic acid; this reaction might represent a viable chemical route to solve the important issue related to the co-production of glycerin along the biodiesel production chain. Acrylic acid yields as high as 51% were obtained and important structure-reactivity correlations were proved to govern the catalytic performance; only fine tuning of acid and redox properties as well as the in-framework presence of vanadium are fundamental to achieve noteworthy yields into the acid monomer. The overall results reported herein might represent an important contribution for future applications of HTBs in catalysis as well as a general guideline for a multifaceted approach for their physicochemical characterization. / [ES] El proyecto de esta tesis doctoral está basado en un convenio de cotutela firmado por la Università di Bologna, ALMA MATER STUDIORUM (Italia) y el Instituto de Tecnología Química, Universitat Politècnica de València ITQ-UPV (España). La presente tesis doctoral muestra el estudio sobre la síntesis, caracterización y ensayos catalíticos de materiales complejos a base de óxidos mixtos relacionados con la familia de los bronces de tungsteno hexagonales. Estos materiales han sido utilizados minoritariamente como catalizadores, aunque tienen un potencial importante come materiales multifuncionales. Sus peculiares propiedades acidas pueden ser acopladas con otras características (por ejemplo, sitios oxido-reductivos) a través de la substitución isomórfica de átomos de tungsteno con otros metales de transición como vanadio, niobio y molibdeno. En esta tesis doctoral se ha demostrado como sea posible preparar bronces de tungsteno hexagonales substituidos a través de síntesis hidrotermal; estos óxidos mixtos fueron caracterizados por completo empleando numerosas técnicas de caracterización quimico-fisicas como XPS, HR-TEM, XAS etc. Fueron también utilizados como catalizadores para la síntesis directa de acido acrílico de glicerol; esta es una reacción que puede representar una solución viable para el problema relacionado con la coproducción de glicerina a lo largo de la cadena productiva del biodiesel. Rendimientos en acido acrílico hasta el 51% fueron obtenidos y importantes relaciones entre las estructuras y la actividad catalítica fueron demostradas ser determinantes para el proceso catalítico; solo la afinación de las propiedades acidas y redox tanto como la presencia en-red de vanadio son esenciales para conseguir rendimientos relevantes en el monómero acido. En general, los resultados presentados en esta tesis doctoral pueden ser una contribución relevante para futuras aplicaciones de los bronces de tungsteno hexagonales en catálisis y también como una guía general para un completa caracterización quimico-fisica de estos oxidos. / [CAT] Esta tesi doctoral està basada en un conveni de cotutela signat per la Università di Bologna, ALMA MATER STUDIORUM (Italia) i el Institut de Tecnologia Química , Universitat Politècnica de València ITQ-UPV(Espanya). La present tesi doctoral estudia la síntesis, caracterització i assajos catalítics de òxids mixtes relacionats amb la família dels bronzes de tungstèn hexagonals. Aquestos materials presenten un gran potencial com materials multi funcionals, encara que no han sigut molt emprats com catalitzadors. Les propietats àcides particulars de aquestos materials poden ser potenciades amb altres característiques (per exemple, llocs redox) mitjançant la substitució isomòrfica d'àtoms de tungstèn amb altres metalls de transició com vanadi, niobi i molibdè. En aquesta tesi doctoral es demostra com es possible sintetitzar bronzes de tungstèn hexagonals substituïts a partir de síntesis hidrotermal. Aquestos òxids mixtes han segut caracteritzats emprant diverses tècniques de caracterització físico-químiques com XPS, HR-TEM, XAS, etc... Per altra part, s'han utilitzat com catalitzadors per a la síntesis directa de àcid acrílic a partir de glicerol, aquesta reacció pot representar una solució viable per al problema relacionat amb la coproducció de glicerina al llarg de la cadena productiva de biodiesel. S'han obtingut rendiments a àcid acrílic del 51%. A més, s'han observat importants relacions entre les estructures i la activitat catalítica, les quals han sigut determinants per al procés catalític. El ajust de les propietats àcides i redox i la presència en red de vanadi són essencials per a obtindre rendiments rellevants en el monòmer àcid. En general, el resultats presentats en aquesta tesi doctoral poden ser una contribució rellevant per a futures aplicacions del bronzes de tungstèn hexagonal en catàlisis i també com una guia general per a una completa caracterització físico-química d'aquestos òxids. / Chieregato, A. (2015). Glycerol oxidehydration to acrylic acid on complex mixed-metal oxides [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/49558 / TESIS