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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

Efeito da suplementação de β-caroteno sintético no DNA e no metabolismo de células hepáticas de ratos recebendo etanol / Effect of synthetic (β-carotene supplementattion in the DNA and metabolism of hepatic cells of rats receiving ethanol

Zanuto, Marcia Elena 03 May 2005 (has links)
A suplementação de &#946;-caroteno em fumantes e alcoólatras pode promover efeitos indesejáveis, manifestando a característica pró-oxidante deste carotenóide. Sabendo que o fígado é o principal órgão de armazenamento de vitamina A e (&#946;-caroteno, e local de oxidação do etanol, o presente estudo buscou investigar no fígado de ratos, a influência da suplementação de (&#946;-caroteno isolado ou associado ao etanol, sobre o metabolismo celular, danos no DNA, proliferação celular e função da proteína p53. Os ratos receberam dietas líquidas contendo (&#946;-caroteno (24mg/L dieta) com (GAB) ou sem (GBC) a adição de etanol (36% da calorias totais da dieta) e dieta líquida normal (isenta de &#946;-caroteno e etanol) (GDN), durante seis semanas de período experimental. Após este período, os animais foram sacrificados para determinações hepáticas e plasmáticas de (&#946;-caroteno, retinol, palmitato de retinila, presença de esteatose, determinações hepáticas de SRATB e GSH, danos no DNA de hepatócitos e expressão do PCNA e da proteína p53. Os resultados mostraram diferenças (p<0,05) entre os grupos quanto as concentrações hepáticas de retinol (&#181;g/g) (GAB: 2,49 ± 0,25; GBC: 4,22 ± 0,24; GDN: 2,83 ± 0,21) e palmitato de retinila (&#181;g/g) (GAB: 40,87 ± 3,98; GBC: 83,72 ± 6,00; GDN: 46,33 ± 3,60), concentração plasmática de retinol (llmol/L) (GAB: 1,42 ± 0,12; GBC: 0,69 ± 0,06; GDN: 2,37 ± 0,28), presença de esteatose (GAB: 2,30 ± 0,21; GBC: 1,00 ± 0,00; GDN: 1,00 ± 0,00), danos no DNA de hepatócitos (danos DNA/100 hepatócitos) (GAB: 285,90 ± 15,20; GBC: 273,83 ± 13,39; GDN: 138,00 ± 4,04) e expressão do PCNA (%0) (GAB: 7,12 ± 1,46; GBC: 1,47 ± 0,27; GDN: 2,04 ± 0,31). As concentrações hepáticas e plasmáticas de &#946;-caroteno, SRATB e GSH hepáticos, não apresentaram diferença (p>0,05) entre os grupos. A proteína p53 não foi expressa em nenhum dos grupos estudados. Estes resultados mostraram que o (&#946;-caroteno isolado e em associação com o etanol não influenciaram na peroxidação lipídica e na expressão da proteína p53. A associação &#946;-caroteno + etanol foi mais prejudicial ao fígado, promovendo alterações no metabolismo celular dos hepatócitos, esteatose, danos no DNA e proliferação celular, considerando que o &#946;-caroteno isolado foi genotóxico ao hepatócito. / &#946;-carotene, when supplemented in smokers and alcohol drinkers may act as prooxidant, resulting in undesirable effects. The liver is the &#946;-carotene and vitamin A main storage organ and where ethanol oxidation takes place. This study investigated in rats\' liver, the influence of &#946;-carotene supplementation either alone or associated with ethanol in cellular metabolism, DNA damage, cellular proliferation and p53 protein function. Three groups of 12 rats received liquid diets containing &#946;-carotene (24mg/L diet) with (BAG) or without (CBG) ethanol (36% of total energy intake). Control animals received liquid diet free of ethanol and &#946;-carotene (NDG). After 6 weeks the animals were sacrificed for hepatic and plasma concentrations of &#946;-carotene, retinol, palmitate retinyl, steatosis, GSH and TBARS, DNA damage, PCNA and p53 expression were evaluated in the liver. Differences were significant for hepatic (BAG: 2.49 ± 0.25; CBG: 4.22 ± 0.24; NDG: 2.83 ± 0.21 mg/g) and plasmatic (BAG: 1.42 ± 0.12; CBG: 0.69 ± 0.06; NDG: 2,37 ± 0,28mmol/L) retinol and hepatic palmitate retinyl (BAG: 40.87 ± 3.98; CBG: 83.72 ± 6.00; NDG: 46.33 ± 3.60), steatosis (BAG: 2.30 ± 0.21; CBG: 1.00 ± 0.00; NDG: 1.00 ± 0.00), DNA damage (BAG: 285.90 ± 15.20; CBG: 273.83 ± 13.39; NDG: 138.00 ±4.04 DNA damages/100 hepatocytes) and PCNA expression (BAG: 7.12 ± 1.46; CBG: 1.47 ± 0.27; NDG: 2.04 ± 0.31) among the groups (p<0.05). Hepatic and plasmatic concentrations of &#946;carotene, TBARS and GSH were not statistically different. p53 staining was not detected in any group. This suggests that &#946;-carotene alone or with ethanol association does not influence lipid peroxidation and p53 expression. &#946;-carotene+ethanol caused metabolic alteration, steatosis, DNA damage and cellular proliferation in hepatocytes. Furthermore, supplementation with &#946;-carotene alone had genotoxic effects in the liver.
472

Complex photonic structures in nature : from order to disorder

Onelli, Olimpia Domitilla January 2018 (has links)
Structural colours arise from the interaction of visible light with nano-structured materials. The occurrence of such structures in nature has been known for over a century, but it is only in the last few decades that the study of natural photonic structures has fully matured due to the advances in imagining techniques and computational modelling. Even though a plethora of different colour-producing architectures in a variety of species has been investigated, a few significant questions are still open: how do these structures develop in living organisms? Does disorder play a functional role in biological photonics? If so, is it possible to say that the optical response of natural disordered photonics has been optimised under evolutionary pressure? And, finally, can we exploit the well-adapted photonic design principles that we observe in Nature to fabricate functional materials with optimised scattering response? In my thesis I try to answer the questions above: I microscopically investigate $\textit{in vivo}$ the growth of a cuticular multilayer, one of the most common colour-producing strategies in nature, in the green beetles $\textit{Gastrophysa viridula}$ showing how the interplay between different materials varies during the various life stages of the beetles; I further investigate two types of disordered photonic structures and their biological role, the random array of spherical air inclusions in the eggshells of the honeyguide $\textit{Prodotiscus regulus}$, a species under unique evolutionary pressure to produce blue eggs, and the anisotropic chitinous network of fibres in the white beetle $\textit{Cyphochilus}$, the whitest low-refractive index material; finally, inspired by these natural designs, I fabricate and study light transport in biocompatible highly-scattering materials.
473

Molecular Evolution and Functional Characterization of the Visual Pigment Proteins of the Great Bowerbird (Chlamydera nuchalis) and Other Vertebrates

van Hazel, Ilke 16 December 2013 (has links)
Visual pigments are light sensitive receptors in the eye that form the basis of sensory visual transduction. This thesis presents three studies that explore visual pigment proteins in vertebrates using a number of computational and experimental methods in an evolutionary framework. The objective is not only to identify, but also to experimentally investigate the functional consequences of genetic variation in vertebrate visual pigments. The focus is on great bowerbirds (Chlamydera nuchalis), which are a model system in visual ecology due to their spectacular behaviour of building and decorating courtship bowers. There are 4 chapters: Chapter 1 introduces background information on visual pigments and vision in birds. Among visual pigment types, the short-wavelength-sensitive (SWS1) pigments have garnered particular interest due to the broad spectral range among vertebrates and the importance of UV signals in communication. Chapter 2 investigates the evolutionary history of SWS1 in vertebrates with a view toward its utility as a phylogenetic marker. Chapter 3 investigates SWS1 evolution and short-wavelength vision in birds, with particular focus on C. nuchalis and its SWS1. The evolution of spectral tuning mechanisms mediating UV/violet vision in passerines and parrots is elucidated in this chapter using site-directed mutagenesis, protein expression, and phylogenetic recreation of ancestral opsins. While cone opsins mediate colour vision in bright light, the rhodopsin visual pigment contained in rod photoreceptors is critical for dim light vision. Detailed characterization of rhodopsin function has only been conducted on a few model systems. Chapter 4 examines C. nuchalis RH1 using a number of functional assays in addition to absorbance spectra, including hydroxylamine sensitivity and the rate of retinal release. This chapter includes an investigation into the role of amino acid mutations typical of dim-light adapted vertebrates, D83N and A292S, in regulating functional properties of bovine and avian RH1s using site-directed mutagenesis. Together these chapters describe naturally occurring mutations in visual pigments and explore the way they can influence visual perception. These represent one of the few investigations of visual pigments from a species that is not a model lab organism and form a significant contribution to the field of visual pigment biochemistry and evolution.
474

Efeito da suplementação de &#946;-caroteno sintético no DNA e no metabolismo de células hepáticas de ratos recebendo etanol / Effect of synthetic (&#946;-carotene supplementattion in the DNA and metabolism of hepatic cells of rats receiving ethanol

Marcia Elena Zanuto 03 May 2005 (has links)
A suplementação de &#946;-caroteno em fumantes e alcoólatras pode promover efeitos indesejáveis, manifestando a característica pró-oxidante deste carotenóide. Sabendo que o fígado é o principal órgão de armazenamento de vitamina A e (&#946;-caroteno, e local de oxidação do etanol, o presente estudo buscou investigar no fígado de ratos, a influência da suplementação de (&#946;-caroteno isolado ou associado ao etanol, sobre o metabolismo celular, danos no DNA, proliferação celular e função da proteína p53. Os ratos receberam dietas líquidas contendo (&#946;-caroteno (24mg/L dieta) com (GAB) ou sem (GBC) a adição de etanol (36% da calorias totais da dieta) e dieta líquida normal (isenta de &#946;-caroteno e etanol) (GDN), durante seis semanas de período experimental. Após este período, os animais foram sacrificados para determinações hepáticas e plasmáticas de (&#946;-caroteno, retinol, palmitato de retinila, presença de esteatose, determinações hepáticas de SRATB e GSH, danos no DNA de hepatócitos e expressão do PCNA e da proteína p53. Os resultados mostraram diferenças (p<0,05) entre os grupos quanto as concentrações hepáticas de retinol (&#181;g/g) (GAB: 2,49 ± 0,25; GBC: 4,22 ± 0,24; GDN: 2,83 ± 0,21) e palmitato de retinila (&#181;g/g) (GAB: 40,87 ± 3,98; GBC: 83,72 ± 6,00; GDN: 46,33 ± 3,60), concentração plasmática de retinol (llmol/L) (GAB: 1,42 ± 0,12; GBC: 0,69 ± 0,06; GDN: 2,37 ± 0,28), presença de esteatose (GAB: 2,30 ± 0,21; GBC: 1,00 ± 0,00; GDN: 1,00 ± 0,00), danos no DNA de hepatócitos (danos DNA/100 hepatócitos) (GAB: 285,90 ± 15,20; GBC: 273,83 ± 13,39; GDN: 138,00 ± 4,04) e expressão do PCNA (%0) (GAB: 7,12 ± 1,46; GBC: 1,47 ± 0,27; GDN: 2,04 ± 0,31). As concentrações hepáticas e plasmáticas de &#946;-caroteno, SRATB e GSH hepáticos, não apresentaram diferença (p>0,05) entre os grupos. A proteína p53 não foi expressa em nenhum dos grupos estudados. Estes resultados mostraram que o (&#946;-caroteno isolado e em associação com o etanol não influenciaram na peroxidação lipídica e na expressão da proteína p53. A associação &#946;-caroteno + etanol foi mais prejudicial ao fígado, promovendo alterações no metabolismo celular dos hepatócitos, esteatose, danos no DNA e proliferação celular, considerando que o &#946;-caroteno isolado foi genotóxico ao hepatócito. / &#946;-carotene, when supplemented in smokers and alcohol drinkers may act as prooxidant, resulting in undesirable effects. The liver is the &#946;-carotene and vitamin A main storage organ and where ethanol oxidation takes place. This study investigated in rats\' liver, the influence of &#946;-carotene supplementation either alone or associated with ethanol in cellular metabolism, DNA damage, cellular proliferation and p53 protein function. Three groups of 12 rats received liquid diets containing &#946;-carotene (24mg/L diet) with (BAG) or without (CBG) ethanol (36% of total energy intake). Control animals received liquid diet free of ethanol and &#946;-carotene (NDG). After 6 weeks the animals were sacrificed for hepatic and plasma concentrations of &#946;-carotene, retinol, palmitate retinyl, steatosis, GSH and TBARS, DNA damage, PCNA and p53 expression were evaluated in the liver. Differences were significant for hepatic (BAG: 2.49 ± 0.25; CBG: 4.22 ± 0.24; NDG: 2.83 ± 0.21 mg/g) and plasmatic (BAG: 1.42 ± 0.12; CBG: 0.69 ± 0.06; NDG: 2,37 ± 0,28mmol/L) retinol and hepatic palmitate retinyl (BAG: 40.87 ± 3.98; CBG: 83.72 ± 6.00; NDG: 46.33 ± 3.60), steatosis (BAG: 2.30 ± 0.21; CBG: 1.00 ± 0.00; NDG: 1.00 ± 0.00), DNA damage (BAG: 285.90 ± 15.20; CBG: 273.83 ± 13.39; NDG: 138.00 ±4.04 DNA damages/100 hepatocytes) and PCNA expression (BAG: 7.12 ± 1.46; CBG: 1.47 ± 0.27; NDG: 2.04 ± 0.31) among the groups (p<0.05). Hepatic and plasmatic concentrations of &#946;carotene, TBARS and GSH were not statistically different. p53 staining was not detected in any group. This suggests that &#946;-carotene alone or with ethanol association does not influence lipid peroxidation and p53 expression. &#946;-carotene+ethanol caused metabolic alteration, steatosis, DNA damage and cellular proliferation in hepatocytes. Furthermore, supplementation with &#946;-carotene alone had genotoxic effects in the liver.
475

Avaliação do metabolismo oxidativo em Pitcairnia encholirioides L. B. Sm. (Bromeliaceae) in vitro e ex vitro e sob desidratação

Resende, Cristiano Ferrara de 05 March 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-23T12:29:44Z No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) / Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: Primeira letra de cada palavra chave em maiúsculo, a não ser que seja nome próprio on 2016-07-02T11:34:23Z (GMT) / Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-04T10:21:07Z No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:11:52Z (GMT) No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) / Made available in DSpace on 2016-07-13T16:11:53Z (GMT). No. of bitstreams: 1 cristianoferraraderesende.pdf: 2182147 bytes, checksum: a1f62e02cb7c97296c57ea6461357835 (MD5) Previous issue date: 2012-03-05 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Bromeliaceae é uma família essencialmente neotropical, cujos representantes são muito utilizados para fins paisagísticos. Uma das principais fontes de abastecimento do mercado consumidor de bromélias é o extrativismo o que, associado à destruição do ambiente natural, tem levado a perdas irreparáveis na biodiversidade da família, especialmente na Mata Atlântica, onde cerca de 40% das espécies encontram-se sob alguma categoria de ameaça. Pitcairnia encholirioides L. B. Sm. é uma espécie “criticamente em perigo” de extinção, sendo conhecida somente uma população dessa espécie, com cerca de 900 indivíduos, encontrada em 2004 em um afloramento rochoso muito degradado e sujeito ao fogo e ao pisoteio de animais, no município de Santa Maria Madalena, RJ. A utilização das técnicas de micropropagação pode reverter os riscos de extinção garantindo taxas elevadas de multiplicação, fornecendo material necessário ao mercado consumidor, evitando, dessa forma, o extrativismo das plantas nos seus locais de origem. A instalação e a conservação in vitro de bancos de germoplasma possuem especial importância, garantindo a sobrevivência de espécies raras e/ou endêmicas e fornecendo plantas para iniciativas de reintrodução. A etapa final da micropropagação é a aclimatização ex vitro, realizada após os procedimentos de multiplicação e enraizamento in vitro. A aclimatização é um período crítico para as plantas devido à perda de água, o que causa estresse hídrico e, como consequência, estresse oxidativo, podendo provocar problemas metabólicos e perdas elevadas. No presente trabalho, Pitcairnia encholirioides foi cultivada in vitro por 150 dias em meio de cultura adicionado de dois reguladores de crescimento (GA3 ou ANA), além de duas concentrações de sacarose (15 ou 30 g L-1) e sob dois tipos de vedação dos tubos de ensaio (vedação hermética com tampas e filme de PVC ou vedação com tampas que permitiam trocas gasosas), totalizando 8 tratamentos, período após o qual as plantas foram transferidas para condições ex vitro, em casa de vegetação, permanecendo por mais 180 dias. Dois desses tratamentos foram selecionados para as análises de desidratação, quando suas plantas foram submetidas a 30, 42 ou 54 dias sem irrigação, além do controle irrigado periodicamente, sendo posteriormente reidratadas durante 90 dias. Após os períodos de cultivo in vitro e permanência das plantas em casa de vegetação, foram realizadas análises dos conteúdos de prolina, proteínas totais, atividades das enzimas do metabolismo antioxidativo SOD, CAT, POD e PPO, além 2 dos teores de pigmentos fotossintetizantes. Além desses parâmetros, após desidratação e reidratação foram também avaliados os teores de carboidratos. De maneira geral, o cultivo in vitro em meio adicionado da menor concentração de sacarose e em tubos vedados hermeticamente se mostrou prejudicial, o que foi evidenciado pelo menor acúmulo de prolina, aumentos nas atividades das enzimas antioxidativas e menor acúmulo de pigmentos fotossintéticos. Após o período de aclimatização, não foram encontradas diferenças entre os tratamentos para a maioria dos parâmetros analisados, ou os dados oscilaram de maneira a não permitir uma generalização quanto aos efeitos residuais da sacarose, do tipo de tampa e dos reguladores de crescimento utilizados durante o cultivo in vitro. No período em que as plantas foram submetidas à desidratação progressiva, houve maior acúmulo de prolina e proteínas solúveis totais, além de aumento nos teores de pigmentos fotossintéticos nos tecidos provenientes de plantas cultivadas in vitro em meio contendo 30 g L-1 de sacarose e GA3. Houve também, em geral, queda mais acentuada nas atividades das enzimas em meio suplementado com a menor concentração de sacarose e ANA, além de oscilações nos teores de pigmentos. As relações entre os pigmentos sofreram leve redução em ambos os tratamentos, e os teores de carboidratos solúveis totais, sacarose, açúcares redutores e amido aumentaram com o prolongamento do estresse. Após a reidratação, todas as plantas demonstraram elevada capacidade de recuperação, apresentando em todas as análises realizadas valores muito similares aos das plantas do controle, não submetidas à desidratação. Os resultados obtidos no trabalho permitem concluir que o cultivo in vitro em meio adicionado de 30 g L-1 de sacarose e em tubos de ensaio que permitem trocas gasosas é o mais apropriado para plantas de P. encholirioides. Ademais, a concentração de sacarose adicionada ao meio de cultura também influencia o desenvolvimento das plantas após aclimatização, sendo encontrados melhores resultados em plantas cultivadas nos meios de cultura suplementados com a maior concentração desse carboidrato. Acredita-se que as plantas cultivadas nessas condições apresentariam maior capacidade de sobrevivência ao transplantio e maior resistência a períodos prolongados de estresse hídrico, aos quais, frequentemente, estão submetidas no ambiente natural. / Bromeliaceae is essentially a neotropical family, whose representatives are widely used for landscaping. One major source of supply for the consumer market is the extraction, which coupled with the destruction of the natural environment, has led to irreparable losses in biodiversity of the family, especially in the Atlantic Forest, where about 40% of bromeliad species are under some category of threat. Pitcairnia encholirioides L. B. Sm. is a critically endangered species. In 2004, a unique population of this species was found, with about 900 individuals in a very degraded rocky outcrop, subject to fire and trampling by animals, located in Santa Maria Madalena, RJ. The use of micropropagation can guarantee high multiplication rates, providing necessary material for the consumer market, effectively obviating the extraction of plants in their places of origin. In addition, installation and in vitro conservation of germplasm banks have special importance, ensuring the survival of rare species and/or endemic and providing micropropagated plants for reintroduction initiatives. Following the procedures of in vitro multiplication and rooting, the final stage of micropropagation is the ex vitro acclimatization, a critical period for the plants due to water loss, which causes water stress and, consequently, oxidative stress, which can cause metabolic problems and high losses. In this study, Pitcairnia encholirioides was grown for 150 days in vitro in a culture medium supplemented with two growth regulators (GA3 or NAA), and two concentrations of sucrose (15 or 30 g L-1) in two types of sealing of test tubes (hermetic seal with lids and PVC film and seal with lids that allowed gas exchange), totaling eight treatments, after which the plants were transferred to ex vitro conditions in a greenhouse, staying for more than 180 days. Two of these treatments were selected for analysis of dehydration when their plants were subjected to 30, 42 or 54 days without irrigation, apart from control irrigated periodically, being subsequently rehydrated for 90 days. After periods of in vitro cultivation and maintenance of the plants in the greenhouse, they were analyzed for proline content, total protein, activities of antioxidant metabolism enzymes SOD, CAT, POD and PPO, besides the content of photosynthetic pigments. Apart from these parameters, after dehydration and rehydration, levels of carbohydrates were also assessed. In general, the in vitro culture in medium containing the lowest concentration of sucrose and hermetically sealed tubes proved to be harmful, which was evidenced by lower levels of proline, increased 4 activity of antioxidant enzymes and lower accumulation of photosynthetic pigments. After the acclimatization period, no differences were found between treatments for most parameters, or data varied so as to not allow a generalization about the residual effects of sucrose, the type of cover and of the growth regulators used in the in vitro cultivation. During the period in which the plants were subjected to water stress, higher accumulation of proline and total soluble proteins occurred, and also increased levels of photosynthetic pigments in tissues from plants grown in vitro in medium containing 30 g L-1 sucrose and GA3. There was also, in general, sharper decrease in enzyme activity in medium with the lowest concentration of sucrose and NAA, as well as fluctuations in pigment. Relations between pigments suffered slight reduction in both treatments, and total soluble carbohydrates, sucrose, reducing sugars and starch increased with increasing stress. After rehydration, all plants showed high resilience, presenting for all analyzes values very similar to those of control plants not subjected to dehydration. The results indicate that the in vitro culture in medium supplemented with 30 g L-1 sucrose and tubes that allow gas exchange are the most appropriate. Moreover, the concentration of sucrose added to the culture medium also influences the development of plants after acclimatization, with best results found in plants grown in media supplemented with higher amount of this carbohydrate. It is believed that plants grown under these conditions would have higher capacity of resistance to transplanting and could survive for prolonged periods of water stress, which are often subjected in the natural environment.
476

Využití hmotnostní spektrometrie pro analýzu biologicky aktivních a klinicky významných látek. / Application of Mass Spectrometry for Analysis of Biologically Active and Clinically Significant Compounds.

Štícha, Martin January 2016 (has links)
- 8 - ABSTRACT (EN) The thesis is submitted as a commented set of reviewed publications documenting and depicting the possibilities of mass spectrometry in the field of chemical, biological and pharmaceutical research; namely for the purposes of structure elucidation of selected organometallic complexes, analyses of drugs and their metabolites, monitoring of important biological markers. In course of experimental work, the following objectives were studied and solved:  Proposal and realization of micro-scale preparation of selected rhenium complexes with aromatic ligands, utilizing tetrabutyammonium tetrachlorooxorhenate as a starting material; preparation and structure characterization of oxorhenium(V) complexes with 1,2-dihydroxybenzene, 1,2,3-trihydroxybenzene, and 2,3- dihydroxynaphtalene as ligands by means of ESI/MS, APPI/MS and LDI-MS; ESI/MS and UV/Vis study of kinetic behavior of complexes arising from the reaction of tetrabutylamonnium tetrachlooxorhenate with pyrogallol and catechol as ligands. Special aim was devoted to the study of subsequent chemical transformation of primarily formed Re(V) complexes; structure characterization of selected ferrocene complexes with copper, gold and silver by means of ESI/MS.  Proposal of methodology of structure characterization and quantification of the...
477

Development of Biotechnological Tools for the Genetic Improvement of Pepino (Solanum Muricatum) and Tree Tomato (S.betaceum)

Pacheco Toabanda, Juan Enrique 07 November 2022 (has links)
Tesis por compendio / [ES] El pepino dulce (Solanum muricatum) y el tomate de árbol (S. betaceum) pertenecen al grupo de cultivos de la familia Solanaceae. Estos dos cultivos son originarios de América del Sur y actualmente se cultivan en varios países con climas tropicales, subtropicales y mediterráneos. Han sido infrautilizados durante mucho tiempo y han cobrado relevancia solo en los últimos años debido a su alta calidad nutricional. El pepino dulce exhibe niveles significativos de potasio, vitamina C y carotenoides y se informa que presenta propiedades antioxidantes, antidiabéticas, antiinflamatorias y antitumorales. Sus frutos se pueden consumir tanto como postre o en ensaladas. El tomate de árbol también destaca por su alto contenido en compuestos bioactivos como carotenoides, antocianinas, flavonoides y vitaminas. Varios productos como jugos, mermeladas, salsas y productos farmacéuticos son elaborados a partir de sus frutos. Debido a que estos cultivos se han introducido en nuevas regiones, donde pueden estar expuestos a estreses bióticos y abióticos que pueden amenazar su producción, y dado que el pepino dulce se ve especialmente afectado por la escasez de agua, fue necesario realizar un estudio para determinar la respuesta de siete cultivares de pepino dulce a parámetros fisiológicos y bioquímicos al estrés por sequía. Este trabajo puede ayudar a desarrollar programas de selección y mejoramiento que permitan generar nuevas variedades más tolerantes a la sequía. Por otro lado, en los países de clima mediterráneo, el pepino dulce se cultiva como cultivo protegido, aplicando las mismas técnicas agrícolas que otras solanáceas como el tomate y el pimiento. Estos sistemas agrícolas también brindan condiciones óptimas para el desarrollo de enfermedades como Fusarium oxysporum f. sp. lycopersici (FOL), Verticillium dahliae (VE), virus del mosaico del pepino (PepMV) y virus del mosaico del tomate (ToMV), que potencialmente podrían causar grandes daños a los cultivos de pepino dulce. Por tal motivo, se realizó un estudio para evaluar la respuesta de una colección de pepino dulce y sus parientes silvestres contra estas cuatro enfermedades, y encontrar fuentes de resistencia/tolerancia a estos patógenos. Aunque el tomate de árbol es un cultivo frutal importante debido a su valor nutricional y efectos beneficiosos para la salud, actualmente no hay información genómica y transcriptómica disponible públicamente. Por lo tanto, fue fundamental secuenciar el transcriptoma de dos cultivares de tomate de árbol con frutos morados (A21) y frutos anaranjados (A23). Estos dos cultivares han sido ampliamente utilizados y cultivados comercialmente en países de la región andina como Ecuador y Colombia. La obtención del primer transcriptoma de tomate de árbol ha permitido realizar un estudio comparativo entre el tomate de árbol y sus especies cercanas, tomate y patata, identificar genes implicados en la ruta de biosíntesis de carotenoides y desarrollar marcadores de polimorfismo de nucleótido único (SNP). En general, esta Tesis Doctoral aporta información relevante sobre la respuesta del pepino a diversos estreses ambientales, que puede ser utilizada para el desarrollo de nuevas variedades de pepino resistentes a múltiples estreses. Mientras que en tomate de árbol, el desarrollo de herramientas genómicas acelerará los programas de mejoramiento. / [CA] El cogombre dolç (Solanum muricatum) i tomata d'arbre (S. betaceum) pertanyen al grup de cultius de la família Solanaceae. Aquests dos cultius són originaris d'Amèrica del Sud i actualment es cultiven en diversos països amb climes tropicals, subtropicals i mediterranis. Han sigut infrautilitzats durant molt de temps i han cobrat rellevància només en els últims anys a causa de la seua alta qualitat nutricional. El cogombre dolç exhibeix nivells significatius de potassi, vitamina C i carotenoides i s'informa que presenta propietats antioxidants, antidiabètiques, antiinflamatòries i antitumorals. Els seus fruits es poden consumir tant com postres o en ensalades. La tomaca d'arbre també destaca pel seu alt contingut en compostos bioactivos com carotenoides, antocianinas, flavonoides i vitamines. Dels seus fruits s'elaboren diversos productes com a sucs, melmelades, salses i productes farmacèutics. Pel fet que aquests cultius s'han introduït en noves regions on poden estar exposats a estressos biòtics i abiòtics que poden amenaçar la seua producció, atés que el cogombre es veu especialment afectat per l'escassetat d'aigua, va ser necessari realitzar un estudi per a determinar la resposta de set cultivars de cogombre dolç a paràmetres fisiològics i bioquímicos a l'estrés per sequera. Aquest treball pot ajudar a desenvolupar programes de selecció i millorament que permeten generar noves varietats més tolerants a la sequera. D'altra banda, als països de clima mediterrani, el cogombre dolç es cultiva com a cultiu protegit, aplicant les mateixes tècniques agrícoles que unes altres solanáceas com la tomaca i el pimentó. Aquests sistemes agrícoles també brinden condicions òptimes per al desenvolupament de malalties com Fusarium oxysporum f. sp. lycopersici (FOL), Verticillium dahliae (VE), virus del mosaic del cogombre (PepMV) i virus del mosaic de la tomaca (ToMV), que potencialment podrien causar grans danys als cultius de cogombre dolç. Per tal motiu, es va realitzar un estudi per a avaluar la resposta d'una col·lecció de cogombre dolç i els seus parents silvestres contra aquestes quatre malalties, i trobar fonts de resistència/tolerància a aquests patògens. Encara que la tomaca d'arbre és un cultiu fruiter important a causa del seu valor nutricional i efectes beneficiosos per a la salut, actualment no hi ha informació genòmica i transcriptómica disponible públicament. Per tant, va ser fonamental seqüenciar el transcriptoma de dues cultivars de tomaca d'arbre amb fruits morats (A21) i fruits ataronjats (A23). Aquestes dues cultivars han sigut àmpliament utilitzats i cultivats comercialment en països de la regió andina com l'Equador i Colòmbia. L'obtenció del primer transcriptoma de tomaca d'arbre ha permés realitzar un estudi comparatiu entre la tomaca d'arbre i les seues espècies pròximes, tomaca i creïlla, identificar gens implicats en la ruta de biosíntesi de carotenoides i desenvolupar marcadors de polimorfisme de nucleòtid únic (SNP). En general, aquesta Tesi Doctoral aporta informació rellevant sobre la resposta del cogombre a diversos estressos ambientals, que pot ser utilitzada per al desenvolupament de noves varietats de cogombre resistents a múltiples estressos. Mentre que en tomaca d'arbre, el desenvolupament d'eines genòmiques accelerarà els programes de millorament. / [EN] Pepino (Solanum muricatum) and tree tomato (S. betaceum) belong to the group of crops of the Solanaceae family. These two crops are native to South America and currently are grown in various countries with tropical, subtropical and Mediterranean climates. They have been underutilized for a long time and have become relevant only in recent years due to their high nutritional quality. Pepino exhibit significant levels of potassium, vitamin C and carotenoids and it is reported to present antioxidant, antidiabetic, anti-inflammatory and antitumor properties. Its fruits can be consumed both as a dessert or in salads. Tree tomato also highlights high content of bioactive compounds such as carotenoids, anthocyanins, flavonoids and vitamins. Severals products such as juices, jams, sauces and pharmaceutical products are made from its fruits. Due to these crops have been introduced into new regions, where they may be exposed to biotic and abiotic stresses that can threaten their production, and since pepino is specially affected by water scarcity, a study was needed to determine the response of seven pepino cultivars to physiological and biochemical parameters to drought stress. This work can help develop selection and improvement programs that allow the generation of new varieties that are more tolerant to drought. On the other hand, in countries with a Mediterranean climate, pepino is grown as a protected crop, applying the same agricultural techniques as other solanaceous plants such as tomato and pepper. These agricultural systems also provide optimal conditions for the development of diseases such as Fusarium oxysporum f. sp. lycopersici (FOL), Verticillium dahliae (VE), pepino mosaic virus (PepMV) and tomato mosaic virus (ToMV), which could potentially cause great damage to pepino crops. For this reason, a study was performed to evaluate the response of a collection of pepino and their wild relatives against these four diseases, and find sources of resistance/tolerance to those pathogens. Although tree tomato is an important fruit crop due to its nutritional value and beneficial health effects, there is currently no publicly available genomic and transcriptomic information. Therefore, it was essential to sequence the transcriptome of two tree tomato cultivars with purple fruits (A21) and orange fruits (A23). These two cultivars have been widely used and cultivated commercially in countries of the Andean region such as Ecuador and Colombia. Obtaining the first tree tomato transcriptome has made it possible to perform a comparative study between tree tomato and its close species, tomato and potato, identify genes involved in the carotenoid biosynthesis pathway, and develop single nucleotide polymorphism (SNP) markers. In general, this Doctoral Thesis provides relevant information on the response of pepino to various environmental stresses, which can be used for the development of new varieties of pepino resistant to multiple stresses. While in tree tomato, the development of genomic tools will accelerating up breeding programs. / Pacheco Toabanda, JE. (2022). Development of Biotechnological Tools for the Genetic Improvement of Pepino (Solanum Muricatum) and Tree Tomato (S.betaceum) [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/189205 / Compendio
478

Développement et caractérisation de dérivés dipyrrométhène pour des applications dans le domaine du photovoltaïque

Yvon-Bessette, André 09 1900 (has links)
Ce projet de recherche mené en collaboration industrielle avec St-Jean Photochimie Inc. / PCAS Canada vise le développement et la caractérisation de dérivés dipyrrométhène pour des applications dans le domaine du photovoltaïque. La quête du récoltage des photons se situant dans le proche-infrarouge a été au centre des modifications structurales explorées afin d’augmenter l’efficacité de conversion des cellules solaires de type organique et à pigments photosensibles. Trois familles de composés intégrant le motif dipyrrométhène ont été synthétisées et caractérisées du point de vue spectroscopique, électrochimique, structural ainsi que par modélisation moléculaire afin d’établir des relations structures-propriétés. La première famille comporte six azadipyrrométhènes au potentiel de coordination tétradentate sur des centres métalliques. Le développement d’une nouvelle voie synthétique asymétrique combinée à l’utilisation d’une voie symétrique classique ont permis d’obtenir l’ensemble des combinaisons de substituants possibles sur les aryles proximaux incluant les noyaux 2-hydroxyphényle, 2-méthoxyphényle et 2- pyridyle. La modulation du maximum d’absorption dans le rouge a pu être faite entre 598 et 619 nm. De même, la présence de groupements méthoxyle ou hydroxyle augmente l’absorption dans le violet (~410 nm) tel que démontré par modélisation. La caractérisation électrochimique a montré que les dérivés tétradentates étaient en général moins stables aux processus redox que leur contre-parti bidentate. La deuxième famille comporte dix dérivés BODIPY fusionnés de façon asymétrique en position [b]. L’aryle proximal a été modifié de façon systématique afin de mieux comprendre l’impact des substituents riches en électron et de la fusion de cycles aromatiques. De plus, ces dérivés ont été mis en relation avec une vaste série de composés analogues. Les résultats empiriques ont montré que les propriétés optoélectroniques de la plateforme sont régies par le degré de communication électronique entre l’aryle proximal, le pyrrole sur lequel il est attaché et le noyau indolique adjacent à ce dernier. Les maximums d’absorption dans le rouge sont modulables entre 547 et 628 nm et la fluorescence des composés se situe dans le proche- infrarouge. L’un des composé s’est révélé souhaitable pour une utilisation en photovoltaïque ainsi qu’à titre de sonde à pH. La troisième famille comporte cinq complexes neutres de RuII basés sur des polypyridines et portant un ligand azadipyrrométhène cyclométalé. Les composés ont montré une forte absorption de photons dans la région de 600 à 800 nm (rouge à proche- infrarouge) et qui a pu être étendue au-delà de 1100 nm dans le cas des dérivés portant un ligand terpyridine. L’analyse des propriétés optoélectroniques de façon empirique et théorique a montré un impact significatif de la cyclométalation et ouvert la voie pour leur étude en tant que photosensibilisateurs en OPV et en DSSC. La capacité d’un des complexes à photo-injecter un électron dans la bande de conduction du semi-conducteur TiO2 a été démontré en collaboration avec le groupe du Pr Gerald J. Meyer à University of North Carolina at Chapel Hill, premier pas vers une utilisation dans les cellules solaires à pigments photosensibles. La stabilité des complexes en solution s’est toutefois avérée problématique et des pistes de solutions sont suggérées basées sur les connaissances acquises dans le cadre de cette thèse. / This research project carried out in industrial collaboration with Saint-Jean Photochemicals Inc. / PCAS Canada aims at the development and characterization of dipyrromethene derivatives for photovoltaic applications. The quest for harvesting near- infrared photons was the central focus and various structural modifications were explored to improve the power conversion efficiency of organic and dye-sensitized solar cells (OPV and DSSC, respectively). Three families of chromophores which embedded a dipyrromethene motif were synthesized and characterized through spectroscopy, electrochemistry, X-ray diffraction and computationnal modelization in order to establish their structure-properties relationship. The first family includes six azadipyrromethenes with potential for tetradentate coordination on metallic centers. The development of a new asymmetric synthetic route together with the classical symmetric one allowed access to all possible combinations of derivatives including 2-hydroxyphenyl, 2-methoxyphenyl and 2-pyridyl substituents in the proximal position of the dipyrromethene. Modulation of the absorption maxima in the red ranged between 598 and 619 nm. Also, having methoxy or hydroxy substituents provided an increase of the violet absorption (~410 nm) as established by modelization. Electrochemical characterization showed that the tetradentate azadipyrromethenes were generally less stable towards redox processes as compared to their bidentate counter- parts. The second family includes ten asymmetric benzo[b]-fused BODIPYs where the proximal aryl was systematically modified in order to assess the impact of electron-rich substituents and fused aromatic cycles. The derivatives were further compared to a wide series of related BODIPYs. Empirical results showed the optoelectronic properties are dictated by the extend of electronic communication between the proximal aryl, the pyrrol to which it is attached and the adjacent indolic moiety. Absorption maxima in the red were modulated between 547 nm and 628 nm and the fluorescence was in the near-infrared. One compound proved to be a potential candidate for photovoltaic and pH probe applications. The third family includes five neutral RuII polypyridine complexes bearing a cyclometalated azadipyrromethene ligand. The compounds exhibit strong light absorption in the 600 – 800 nm range (red to near-infrared) that tails beyond 1100 nm in the terpyridine-based adducts. Analysis of the optoelectronic properties showed a significant impact of this novel cyclometalation strategy for dipyrromethene derivatives and paved the way for further incorporation of the resulting complexes as photosensitizers in OPV and DSSC. In collaboration with the group of Pr Gerald J. Meyer at the University of North Carolina at Chapel Hill, the capacity of one compound to photo-inject its electron into the conduction band of the TiO2 semiconductor was established, a first step towards their use in dye-sensitized solar cells. The structural instability in solution of the complexes hindered their full potential for photovoltaic applications and suggestions to improve them are proposed based on the knowledge acquired in the course of this thesis.
479

Cellulose photonics : designing functionality and optical appearance of natural materials

Guidetti, Giulia January 2018 (has links)
Cellulose is the most abundant biopolymer on Earth as it is found in every plant cell wall; therefore, it represents one of the most promising natural resources for the fabrication of sustainable materials. In plants, cellulose is mainly used for structural integrity, however, some species organise cellulose in helicoidal nano-architectures generating strong iridescent colours. Recent research has shown that cellulose nanocrystals, CNCs, isolated from natural fibres, can spontaneously self-assemble into architectures that resemble the one producing colouration in plants. Therefore, CNCs are an ideal candidate for the development of new photonic materials that can find use to substitute conventional pigments, which are often harmful to humans and to the environment. However, various obstacles still prevent a widespread use of cellulose-based photonic structures. For instance, while the CNC films can display a wide range of colours, a precise control of the optical appearance is still difficult to achieve. The intrinsic low thermal stability and brittleness of cellulose-based films strongly limit their use as photonic pigments at the industrial scale. Moreover, it is challenging to integrate them into composites to obtain further functionality while preserving their optical response. In this thesis, I present a series of research contributions that make progress towards addressing these challenges. First, I use an external magnetic field to tune the CNC films scattering response. Then, I demonstrate how it is possible to tailor the optical appearance and the mechanical properties of the films as well as to enhance their functionality, by combining CNCs with other polymers. Finally, I study the thermal properties of CNC films to improve the retention of the helicoidal arrangement at high temperatures and to explore the potential use of this material in industrial fabrication processes, such as hot-melt extrusion.

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