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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.
11

Analysis of physical and chemical properties of fractionated grains and seeds with an emphasis on barley /

Elfverson, Cajsa, January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 6 uppsatser.
12

Nanocomplexos de európio com mesoiônicos 1,3-tiazólio-5-tiolato e bipiridina: avaliação estrutural, térmica e espectrométrica. / Nanocomplexes of europium with mesoionic 1,3-thiazolium -5-thiolate and bipyridine: structural, thermal and spectrometric evaluation.

MOTA, Gabriela Brasileiro Campos. 24 May 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-05-24T18:03:23Z No. of bitstreams: 2 GABRIELA BRASILEIRO CAMPOS MOTA – TESE (PPGEP) 2014.pdf: 2208551 bytes, checksum: aefc619e6f9a0e4440ee264fa9431b59 (MD5) Ficha Catalográfica - GABRIELA BRASILEIRO CAMPOS MOTA – TESE (PPGEP) 2014.pdf: 54437 bytes, checksum: c9ec775e575ff1f890b9adb61626fef7 (MD5) / Made available in DSpace on 2018-05-24T18:03:23Z (GMT). No. of bitstreams: 2 GABRIELA BRASILEIRO CAMPOS MOTA – TESE (PPGEP) 2014.pdf: 2208551 bytes, checksum: aefc619e6f9a0e4440ee264fa9431b59 (MD5) Ficha Catalográfica - GABRIELA BRASILEIRO CAMPOS MOTA – TESE (PPGEP) 2014.pdf: 54437 bytes, checksum: c9ec775e575ff1f890b9adb61626fef7 (MD5) Previous issue date: 2014 / O estudo de nanomateriais tornou-se uma linha muito importante de pesquisa em áreas como a física do estado sólido, química de estado sólido, engenharia de materiais, ciências médicas e biotecnologia. As pesquisas envolvendo a coordenação de íons lantanídicos ganham cada vez mais destaque na área científica, devido suas propriedades luminescentes. Concomitantemente, destacam-se os estudos científicos de compostos orgânicos que apresentam propriedades biológicas, entre os quais se distinguem os compostos mesoiônicos, que apresentam características estruturais, que despertaram um interesse considerável dos investigadores envolvidos na área da Química Medicinal. Neste sentido, a possibilidade de coordenar e associar as propriedades de íons lantanídeos com compostos mesoiônicos, a fim de preservar as características estruturais destes, têm atraído a atenção de pesquisadores. Nesta perspectiva, o presente trabalho teve como objetivo sintetizar pós cristalinos da coordenação do íon európio lantanídeos com mesoiônico do grupo 1,3-tiazolio-5-tiolato e bipiridina, além de caracterizar o complexo Eu(MESO1)3 bipy e Eu(MESO2)3bipy, 2-(4-clorofenil)-3-metil-4-(4-metilfenil)-1,3-tiazólio-5-tiolato (MESO1) e 2-(4-clorofenil)-3-metil-4-fenil-1,3-tiazólio-5-tiolato (MESO2) e a 2,2-bipiridina (bipy). Partindo da reação entre os cloreto de európio,com os ligantes orgânicos, sob refluxo de aproximadamente seis horas os mesoiônicos como segundo ligante, sob agitação magnética e temperatura de 60ºC, foi obtido um pó cristalino de coloração avermelhada. Os resultados das temperaturas de fusão/decomposição dos ligantes quando comparadas aos complexos mostraram-se bastante diferentes, o que indica a formação de novas substâncias. O nanocomplexos de íons lantadínicos apresentaram resultados da análise elementar satisfatórios, comprovando a estequiometria (1:3:1). Os espectros de absorção na regiao do UV-visível apresentaram deslocamento e surgimento de novas bandas, o que confirma a coordenação. A coordenação dos ligantes com o íons landanídicos ocorreu através dos átomos de enxofre exocíclico (C-S-) dos mesoiônicos e dos átomos de nitrogênio (C-N) da bipiridina, observados nos espectros de infravermelho. Os espectros de emissão dos complexos mostram que a emissão não foi potencializada pelo cátion. Os resultados dos difratogramas de raios-x dos complexos apresentam o desaparecimento e surgimento de novos picos, bem como, a variação de intensidade. As micrografias dos complexos confirmaram a formação de aglomerados e evidenciaram a cristalinidade dos compostos. Com base nas curvas termogravimétricas, as temperaturas de decomposição, dentre os complexos sintetizados, o Eu(MESO2)3 bipy apresentou maior estabilidade térmica. As curvas DSC dos complexos mostram um deslocamento dos picos sugestivo da formação de novas espécies. / The study of nanomaterials has become a very important line of research in areas such as solid state physics, solid state chemistry, materials engineering, medical sciences and biotechnology. Research involving the coordination of lanthanide ions are gaining more prominence in science, because their luminescent properties. Conco mitantly, we highlight the scientific study of organic compounds that exhibit biological properties, among which we distinguish the mesoionic compounds that have structural features that have attracted considerable interest from researchers involved in the field of Medicinal Chemistry. In this sense, the ability to coordinate and link the properties of lanthanide ions with mesoionic compounds, in order to preserve the structural characteristics of these have attracted the attention of researchers. In this perspective, the present study aimed to synthesize crystalline powders of europium lanthanide ion coordination with the group mesoionic 1,3-thiazolium -5-thiolate and bipyridine, besides characterizing the complex I (MESO1) 3bipy and I (MESO2) 3bipy 2 - (4-chlorophenyl)-3-methyl-4-(4-methylphenyl) -1,3-thiazolium -5-thiolate (MESO1) and 2 - (4-chlorophenyl)-3-methyl-4-phenyl- 1,3-thiazolium -5-thiolate (MESO2) and 2,2-bipyridine (bipy). Leaving the reaction between europium chloride with organic ligands under reflux for about six hours as the mesoionics second linker, under magnetic stirring and temperature of 60 º C, was obtained a crystalline powder reddish. The results of melting / decomposition of binders compared to the complexes were quite different, indicating the formation of new substances. The nanocomplexos of lantadínicos ions showed satisfactory results of elemental analysis, confirming the stoichiometry (1:3:1). The absorption spectra in the UVvisible region showed displacement and the appearance of new bands, confirming coordination. The coordination of the ligands with landanídicos ions occurred through the exocyclic sulfur atoms (CS-) of mesoionics and nitrogen atoms (CN) of bipyridine observed in the infrared spectra. Emission spectra of the complexes show that the issue was not potentiated by cation. The results of x-ray diffraction patterns of the complexes show the disappearance and appearance of new peaks and the intensity variation. The micrographs confirmed the formation of the complexes and clusters showed the crystallinity of the compounds. Based on the thermogravimetric curves, the decomposition temperatures, among the synthesized complexes, I (MeSO2) 3bipy showed higher thermal stability. The DSC curves of the complexes show a shift of the peaks suggestive of the formation of new species.
13

Biomatériaux auto-supportés et dégradables pour l'ingénierie tissulaire : association d'un gel de fibrine et un réseau de polymère synthétique / Self-supported and degradable biomaterials for tissue engineering : association of a fibrin gel and synthetic polymer network

Deneufchatel, Marie 30 September 2016 (has links)
L’ingénierie tissulaire vise à régénérer des organes ou des tissus lésés. Ainsi, les gels de fibrine sont largement utilisés pour la reconstruction de différents tissus. Cependant, à concentration physiologique, ils ne peuvent pas être manipulés. Pour améliorer leurs propriétés mécaniques, ils peuvent être combinés dans une architecture de Réseaux Interpénétrés de Polymères (RIP) à un réseau de polymère synthétique (PVA ou POE). Ces RIPs peuvent être rendus biodégradables en copolymérisant d’albumine bovine de sérum modifiée par des groupements méthacrylate (BSAm) avec le partenaire synthétique.Selon leurs compositions, ces matériaux peuvent être complètement dégradés ou fragmentés après quelques jours en présence de thermolysine, une enzyme protéolytique. Ces cinétiques de dégradation de ces RIPs ont été étudiées en suivant le relargage des fragments protéiques hors du matériau, d’une part, et la diminution de leurs propriétés viscoélastiques, d’autre part. Leur biocompatibilité a été vérifiée : des fibroblastes cultivés à leur surface présentent une viabilité supérieure à 90% après 5 semaines de culture et leur prolifération est suivie de la synthèse de macromolécules de la Matrice Extracellulaire.Afin de leur ajouter une action bactéricide et d’augmenter encore leur résistance mécanique, des sels d’ammonium ont également été incorporés à certains de ces RIPs. Enfin, la synthèse de tels RIP a été mise au point à partir de plasma sanguin. Les éventuels phénomènes de rejet lors de leur intégration au sein du corps devraient ainsi être limités. De plus, le plasma sanguin contenant un grand nombre de facteurs de croissance et de molécules bioactives, la réparation tissulaire devrait ainsi être améliorée. / Tissue engineering aims to regenerate deficient tissues and organs. Fibrin gels are widely used for the reconstruction of various tissues. However, at physiological concentration, they can’t be handled. To improve their mechanical properties, they can be combined with a synthetic polymeric network (PVA or PEO) in an Interpenetrating Polymer Network (IPN) architecture. These IPN can be made biodegradable by crosslinking the Bovine Serum Albumin modified by methacrylate groups (BSAm) with the synthetic partner.Depending on the composition, these materials can be fully degraded or fragmented after several days of incubation with thermolysin, a proteolytic enzyme. The degradation kinetics of these hydrogels were studied by following the release of proteic fragments from the material and by the loss of viscoelastic properties. The biocompatibility was also verified: fibroblasts cultivated on the surface show a viability of over 90% after 5 weeks of culture and the proliferation is followed by the synthesis of Extracellular Matrix macromolecules.To add a bactericide property, and to increase their mechanical resistance, ammonium salts were incorporated in those IPN. Lastly, the synthesis of these IPN were adapted, starting from whole blood plasma. Rejection phenomena upon implantation should thus be hindered. Moreover, blood plasma contains a wide variety of growth factors and bioactive molecules, which should improve tissue regeneration.
14

Pólen apícola desidratado: composição físico-química, qualidade microbiologica, compostos fenólicos e flavonoides, capacidade antioxidante e origem botânica / Dehydrtated bee pollen: physicochemical, microbiological quality, phenolic and flavonoids compounds, antioxidant and botanical origin.

Arruda, Vanilda Aparecida Soares de 10 October 2013 (has links)
O pólen apícola, produto da aglutinação do pólen das flores com néctar e substâncias salivares das abelhas, tem sido promovido como suplemento da dieta humana por apresentar propriedades nutricionais e bioativas. Sessenta e duas amostras de pólen apícola desidratado foram avaliadas para as análises de compostos fenólicos, flavonoides, atividade antioxidante por três métodos (DPPH, sistema β-caroteno e ORAC), origem botânica, qualidade comercial (umidade, cinzas, lipídeos, proteínas e carboidratos) e sanitária (bolores e leveduras, aeróbios mesófilos, coliformes totais, E.coli, clostrídios sulfito redutores e S.aureus.), além da atividade antimicrobiana (Candida albicans, Escherichia coli, Staphylococcus aureus). Os valores obtidos para compostos fenólicos e flavonoides totais variaram de 12,60 a 84,22 mg GAE/g de pólen apícola (GAE: equivalentes em ácido gálico) e 1,90 a 36,85 mg de quercetina/g de pólen apícola respectivamente. O EC50, determinado pelo método do DPPH, variou de 0,35 a 13,42 mg pólen apícola/mL de extrato. Os extratos de pólen apícola apresentaram valores entre 52,58 e 98,37 % para o método do β-caroteno. Quando quantificada por ORAC, a atividade antioxidante medida ficou entre 132,98 e 575,85 µmol eq. trolox/g pólen apícola. Na avaliação da qualidade comercial foram obtidos os valores de 3,06% a 8,12% para umidade, de 1,94 a 4,61%, para cinzas, de 3,35 a 10,96% para lipídeos; de 17,73 a 34,73% para as proteínas, de 11,86 a 25,71% e de 2,77 a 15,87% para os açúcares frutose e glicose, respectivamente. Verificou-se que a presença do pólen apícola inibiu o crescimento de todos os microrganismos estudados. Candida albicans foi a mais resistente e o Staphylococcus epidermides foi o mais sensível. Observou-se 36 tipos polínicos diferentes, destacando-se: Cocos nucifera sp., Mimosa scabrella (Benth.), Mimosa caesalpiniaefolia sp., Eucalyptus sp., Myrcia sp., Asteraceae, Poaceae., Euphorbiaceae e Brassica que ocorreram com maior frequência entre as amostras estudadas. Foram observadas somente correlações moderadas e fracas entre os tipos polínicos presentes e os parâmetros avaliados para as amostras desidratadas de pólen apícola. / Bee pollen, a product of agglutination of flower pollen with nectar and bee salivary substances, has been promoted as a dietary supplement for human because of its nutritional and bioactive properties. Sixty-two samples of dehydrated bee pollen were analyzed for phenolics, flavonoids, antioxidant activity using three methods (DPPH, βcarotene and ORAC), botanical composition, commercial quality (moisture, ashes, lipids, proteins, carbohydrates), hygiene (aerobic mesophiles, yeasts and moulds, coliforms, Escherichia coli, Staphylococcus aureus and sulfite-reducing Clostridium), and antimicrobial activity (Candida albicans, Escherichia coli, Staphylococcus aureus). The obtained values for total phenolics ranged from 12.60 to 84.22 mg GAE/g bee pollen (GAE: gallic acid equivalents) while for total flavonoids ranged from 1.90 and 36.85 mg quercetin/g bee pollen. The EC50, determined by the DPPH method, ranged from 0.35 to 13.42 mg bee pollen/ml of extract. The bee pollen extracts showed values between 52.58 and 98.37% by β- carotene method. When measured by ORAC, antioxidant activity was between 132.98 and 575.85 µmols eq. trolox/g bee pollen. In the evaluation of commercial quality, the following results were achieved: 3.06% to 8.12% for moisture, 1.94 to 4.61% for ashes, 3.35 to 10.96% for lipids, 17.73 to 34.73% for proteins, from 11.86 to 25.71% and 2.77 to 15.87% for the carbohydrates glucose and fructose respectively. It was verified that the presence of the bee pollen inhibited the growth of all microorganisms studied. Candida albicans was the more resistant and Staphylococcus epidermides the more sensitive. Thirty-three pollen-types were identified mainly Cocos nucifera sp., Mimosa scabrella (Benth.) sp., Mimosa caesalpiniaefolia sp., Eucalyptus sp., Myrcia sp., Asteraceae sp., Poaceae sp., Euphorbiaceae sp. and Brassica sp. that occurred more frequently among the samples studied. It was observed only moderate and weak correlations between the pollen types present and the evaluated parameters for dehydrated samples of bee pollen
15

Formulação à base de Epigalocatequina-3-galato, derivada do chá verde, desenvolvida para uso endodôntico: estudo físico-químico e biológico / Formulation based on Epigallocatechin-3-gallate, derived from green tea, developed for endodontic use: physicochemical and biological study

Ferreira, Danielly Cunha Araújo 28 August 2015 (has links)
O chá verde, obtido da Camellia sinensis, é uma das bebidas mais populares em todo o mundo e, recentemente, tem sido foco de pesquisas científicas por apresentar efeitos benéficos na saúde geral. Estudos laboratoriais e epidemiológicos sugerem que, dentre os polifenóis que compõem o chá verde, a Epigalocatequina-3-galato (EGCG) é o mais bioativo e responsável por sua ação antioxidante, anti-inflamatória, antimicrobiana, inativadora de LPS bacteriano, anticarcinogênica, antitumoral, anti-angiogênica, anti-hipertensiva e reparadora tecidual, podendo atuar na prevenção e tratamento do câncer, doenças cardiovasculares, neurodegenerativas, hepáticas e renais. Em diversas doenças ósseas, a EGCG também desempenha um importante papel protetor, atuando na indução da mineralização e inibição da osteoclastogênese. No entanto, seus possíveis efeitos na inflamação e na reabsorção óssea associadas à lesão periapical ainda não foram avaliados. Portanto, o objetivo do presente estudo foi desenvolver uma formulação para uso endodôntico à base de EGCG com propriedades físico-químicas e biológicas que permitam seu uso como curativo de demora entre sessões. As formulações testadas incluíram: EGCG diluída em água e diferentes concentrações de EGCG (1,25; 5; 10 e 20 mg/mL) veiculadas em polietilenoglicol 400 (PEG). O óxido de zinco foi utilizado como agente radiopacificador. Em função da possível degradação dos produtos fenólicos em função do ambiente e do tempo, uma solução obtida por meio do contato prolongado da EGCG com o dente também foi avaliada (produto da degradação). Inicialmente, foi realizada a caracterização físico-química da formulação de EGCG por meio de espectrofotometria em Ultravioleta/Visível (UV/Vis), em contato com soluções contendo zinco, óxido de zinco e acetato de zinco. Os estudos biológicos foram realizados para avaliar sua compatibilidade tecidual no tecido subcutâneo de camundongos, por meio da avaliação do extravasamento plasmático após 24 horas e da análise de aspectos macroscópicos e microscópicos aos 7, 21 e 63 dias após a inserção de tubos de polietileno contendo as formulações. Neste estudo, uma pasta a base de hidróxido de cálcio (Calen®) foi utilizada como controle. Na análise macroscópica, realizada por meio de fotografias, foram atribuídos escores aos parâmetros de ulceração epitelial, vascularização, necrose e edema. Na análise microscópica, realizada em microscopia de luz convencional e de fluorescência, foram avaliados os parâmetros de infiltrado inflamatório, vascularização, focos de abscessos, cápsula fibrosa, edema e necrose. Os escores dos resultados biológicos foram submetidos à análise estatística utilizando o teste do Qui-quadrado ou Exato de Fisher e para análise dos resultados quantitativos do extravasamento plasmático foi utilizada análise de variância (ANOVA), seguida pelo pós-teste de Tukey. O nível de significância adotado foi de 5%. Os estudos físico-químicos mostraram que a EGCG manteve seu comprimento de onda original em 274 nm quando associada ao óxido de zinco, tendendo à formação de uma banda de absorção em 325 nm. A associação da EGCG com acetato de zinco ocasionou diminuição da banda de absorção em 274 nm e formação de uma nova banda em 323 nm. Os estudos biológicos mostraram, nos parâmetros macroscópicos que, em todos os períodos avaliados, todas as formulações apresentaram compatibilidade tecidual, com ausência de ulceração epitelial, presença de leve necrose tecidual superficial, edema e vascularização, não havendo diferença significante entre os grupos avaliados (p>0,05). Na análise microscópica, em todos os períodos foi verificada ausência de focos de abscesso, edema e necrose e presença de suave ou moderado infiltrado inflamatório, cápsula fibrosa e neovascularização, semelhante entre todos os grupos (p>0,05). A avaliação dos espécimes corados com HE em microscopia de fluorescência favoreceu a visualização dos vasos sanguíneos e de fibras colágenas, constituindo metodologia adicional para esta finalidade. Na avaliação do extravasamento plasmático, o produto da degradação da ECGG apresentou extravasamento de corante azul de Evans por grama de tecido inferior (0,0514 ±0,0220 mg/mL) às demais formulações testadas (p<0,05). Conclui-se que a formulação tópica à base de EGCG, desenvolvida para uso endodôntico, apresenta propriedades físico-químicas estáveis e compatibilidade tecidual. / The green tea, obtained from the Camellia sinensis, is one of the most popular drinks in the world and has recently been in the focus of scientific research due its beneficial effects on general health. Laboratory and epidemiological studies suggest that, among the polyphenols found on green tea, the epigallocatechin-3-gallate (EGCG) is the most bioactive and responsible for its antioxidant, anti-inflammatory, anti-microbial, bacterial LPS inactivation, anticarcinogenic, anti-tumoral, anti-angiogenic, anti-hypertensive and tissue repair and can act in the prevention and treatment of cancer, cardiovascular disease, neurodegenerative, liver and kidney diseases. In several bone diseases, EGCG also plays a major protective role, acting in inhibition of osteoclastogenesis and induction of mineralization. However, their possible effects on inflammation and bone resorption associated to apical periodontitis have not been evaluated. Therefore, the aim of this study was to develop a EGCG based formulation for endodontic use with physicochemical and biological properties that allow its use as intracanal dressing between sessions. The formulations tested included: EGCG diluted in water and different concentrations of EGCG (1.25, 5, 10 and 20 mg/ml) diluted in polyethylene glycol 400 (PEG). Zinc oxide was used as radiopacifier agent. Due to the possible degradation of phenolic compounds as a function of the environment and time, a solution obtained through prolonged contact with the tooth EGCG was also evaluated (degradation product). Initially, physicochemical characterization of EGCG formulation was performed by ultraviolet spectrophotometry/Visible (UV/Vis) in contact with solutions containing zinc, zinc oxide and zinc acetate. Biological studies were conducted to evaluate its tissue compatibility with subcutaneous tissue of mice by means of the evaluation of plasma leakage after 24 hours and the examination of macroscopic and microscopic features at 7, 21 and 63 days after insertion of polyethylene tubes containing the formulations. In this study, a calcium hydroxide pastebase (Calen®) was used as control. The macroscopic analysis performed by means of photographs, assigned scores to epithelial ulceration, vascularization, necrosis and edema parameters. Microscopic examination performed in conventional and fluorescence microscopy assessed the inflammatory infiltrate, vascularization, abscesses spots, fibrous capsule, edema and necrosis parameters. The scores of biological results were statistically analyzed by the chisquare test or Fisher\'s exact and for the quantitative analysis of the results of plasma extravasation the analysis of variance (ANOVA) followed by Tukey\'s post-test were used. The significance level was 5%. The physico-chemical studies showed that EGCG maintained its original wavelength at 274 nm when added to zinc oxide, tending to the formation of an absorption band at 325 nm. The combination of EGCG with zinc acetate led to decreased absorption band at 274 nm and formation of a new band at 323 nm. Biological studies showed, in the macroscopic parameters in all periods, that all formulations showed tissue compatibility, with no epithelial ulceration, presence of mild superficial tissue necrosis, edema and vascularization, with no significant difference between the groups (p > 0.05). On microscopic examination, in all periods was verified absence of abscess foci, edema and necrosis and the presence of mild or moderate inflammatory infiltrate, fibrous capsule and neovascularization, similar among all groups (p> 0.05). The evaluation of the specimens stained with HE under fluorescence microscopy enhancve the visualization of the blood vessels and collagen fibers, constituting an additional methodology for this purpose. In the evaluation of plasma extravasation, the product of degradation of ECGG presented values of Evans blue dye extravasation by gram of tissue (0.0514 ± 0.0220 mg / mL) lower to the other tested formulations (p <0.05). It is concluded that the topical formulation based on EGCG developed for endodontic use, presented stable physical and chemical properties and tissue compatibility.
16

Formulação à base de Epigalocatequina-3-galato, derivada do chá verde, desenvolvida para uso endodôntico: estudo físico-químico e biológico / Formulation based on Epigallocatechin-3-gallate, derived from green tea, developed for endodontic use: physicochemical and biological study

Danielly Cunha Araújo Ferreira 28 August 2015 (has links)
O chá verde, obtido da Camellia sinensis, é uma das bebidas mais populares em todo o mundo e, recentemente, tem sido foco de pesquisas científicas por apresentar efeitos benéficos na saúde geral. Estudos laboratoriais e epidemiológicos sugerem que, dentre os polifenóis que compõem o chá verde, a Epigalocatequina-3-galato (EGCG) é o mais bioativo e responsável por sua ação antioxidante, anti-inflamatória, antimicrobiana, inativadora de LPS bacteriano, anticarcinogênica, antitumoral, anti-angiogênica, anti-hipertensiva e reparadora tecidual, podendo atuar na prevenção e tratamento do câncer, doenças cardiovasculares, neurodegenerativas, hepáticas e renais. Em diversas doenças ósseas, a EGCG também desempenha um importante papel protetor, atuando na indução da mineralização e inibição da osteoclastogênese. No entanto, seus possíveis efeitos na inflamação e na reabsorção óssea associadas à lesão periapical ainda não foram avaliados. Portanto, o objetivo do presente estudo foi desenvolver uma formulação para uso endodôntico à base de EGCG com propriedades físico-químicas e biológicas que permitam seu uso como curativo de demora entre sessões. As formulações testadas incluíram: EGCG diluída em água e diferentes concentrações de EGCG (1,25; 5; 10 e 20 mg/mL) veiculadas em polietilenoglicol 400 (PEG). O óxido de zinco foi utilizado como agente radiopacificador. Em função da possível degradação dos produtos fenólicos em função do ambiente e do tempo, uma solução obtida por meio do contato prolongado da EGCG com o dente também foi avaliada (produto da degradação). Inicialmente, foi realizada a caracterização físico-química da formulação de EGCG por meio de espectrofotometria em Ultravioleta/Visível (UV/Vis), em contato com soluções contendo zinco, óxido de zinco e acetato de zinco. Os estudos biológicos foram realizados para avaliar sua compatibilidade tecidual no tecido subcutâneo de camundongos, por meio da avaliação do extravasamento plasmático após 24 horas e da análise de aspectos macroscópicos e microscópicos aos 7, 21 e 63 dias após a inserção de tubos de polietileno contendo as formulações. Neste estudo, uma pasta a base de hidróxido de cálcio (Calen®) foi utilizada como controle. Na análise macroscópica, realizada por meio de fotografias, foram atribuídos escores aos parâmetros de ulceração epitelial, vascularização, necrose e edema. Na análise microscópica, realizada em microscopia de luz convencional e de fluorescência, foram avaliados os parâmetros de infiltrado inflamatório, vascularização, focos de abscessos, cápsula fibrosa, edema e necrose. Os escores dos resultados biológicos foram submetidos à análise estatística utilizando o teste do Qui-quadrado ou Exato de Fisher e para análise dos resultados quantitativos do extravasamento plasmático foi utilizada análise de variância (ANOVA), seguida pelo pós-teste de Tukey. O nível de significância adotado foi de 5%. Os estudos físico-químicos mostraram que a EGCG manteve seu comprimento de onda original em 274 nm quando associada ao óxido de zinco, tendendo à formação de uma banda de absorção em 325 nm. A associação da EGCG com acetato de zinco ocasionou diminuição da banda de absorção em 274 nm e formação de uma nova banda em 323 nm. Os estudos biológicos mostraram, nos parâmetros macroscópicos que, em todos os períodos avaliados, todas as formulações apresentaram compatibilidade tecidual, com ausência de ulceração epitelial, presença de leve necrose tecidual superficial, edema e vascularização, não havendo diferença significante entre os grupos avaliados (p>0,05). Na análise microscópica, em todos os períodos foi verificada ausência de focos de abscesso, edema e necrose e presença de suave ou moderado infiltrado inflamatório, cápsula fibrosa e neovascularização, semelhante entre todos os grupos (p>0,05). A avaliação dos espécimes corados com HE em microscopia de fluorescência favoreceu a visualização dos vasos sanguíneos e de fibras colágenas, constituindo metodologia adicional para esta finalidade. Na avaliação do extravasamento plasmático, o produto da degradação da ECGG apresentou extravasamento de corante azul de Evans por grama de tecido inferior (0,0514 ±0,0220 mg/mL) às demais formulações testadas (p<0,05). Conclui-se que a formulação tópica à base de EGCG, desenvolvida para uso endodôntico, apresenta propriedades físico-químicas estáveis e compatibilidade tecidual. / The green tea, obtained from the Camellia sinensis, is one of the most popular drinks in the world and has recently been in the focus of scientific research due its beneficial effects on general health. Laboratory and epidemiological studies suggest that, among the polyphenols found on green tea, the epigallocatechin-3-gallate (EGCG) is the most bioactive and responsible for its antioxidant, anti-inflammatory, anti-microbial, bacterial LPS inactivation, anticarcinogenic, anti-tumoral, anti-angiogenic, anti-hypertensive and tissue repair and can act in the prevention and treatment of cancer, cardiovascular disease, neurodegenerative, liver and kidney diseases. In several bone diseases, EGCG also plays a major protective role, acting in inhibition of osteoclastogenesis and induction of mineralization. However, their possible effects on inflammation and bone resorption associated to apical periodontitis have not been evaluated. Therefore, the aim of this study was to develop a EGCG based formulation for endodontic use with physicochemical and biological properties that allow its use as intracanal dressing between sessions. The formulations tested included: EGCG diluted in water and different concentrations of EGCG (1.25, 5, 10 and 20 mg/ml) diluted in polyethylene glycol 400 (PEG). Zinc oxide was used as radiopacifier agent. Due to the possible degradation of phenolic compounds as a function of the environment and time, a solution obtained through prolonged contact with the tooth EGCG was also evaluated (degradation product). Initially, physicochemical characterization of EGCG formulation was performed by ultraviolet spectrophotometry/Visible (UV/Vis) in contact with solutions containing zinc, zinc oxide and zinc acetate. Biological studies were conducted to evaluate its tissue compatibility with subcutaneous tissue of mice by means of the evaluation of plasma leakage after 24 hours and the examination of macroscopic and microscopic features at 7, 21 and 63 days after insertion of polyethylene tubes containing the formulations. In this study, a calcium hydroxide pastebase (Calen®) was used as control. The macroscopic analysis performed by means of photographs, assigned scores to epithelial ulceration, vascularization, necrosis and edema parameters. Microscopic examination performed in conventional and fluorescence microscopy assessed the inflammatory infiltrate, vascularization, abscesses spots, fibrous capsule, edema and necrosis parameters. The scores of biological results were statistically analyzed by the chisquare test or Fisher\'s exact and for the quantitative analysis of the results of plasma extravasation the analysis of variance (ANOVA) followed by Tukey\'s post-test were used. The significance level was 5%. The physico-chemical studies showed that EGCG maintained its original wavelength at 274 nm when added to zinc oxide, tending to the formation of an absorption band at 325 nm. The combination of EGCG with zinc acetate led to decreased absorption band at 274 nm and formation of a new band at 323 nm. Biological studies showed, in the macroscopic parameters in all periods, that all formulations showed tissue compatibility, with no epithelial ulceration, presence of mild superficial tissue necrosis, edema and vascularization, with no significant difference between the groups (p > 0.05). On microscopic examination, in all periods was verified absence of abscess foci, edema and necrosis and the presence of mild or moderate inflammatory infiltrate, fibrous capsule and neovascularization, similar among all groups (p> 0.05). The evaluation of the specimens stained with HE under fluorescence microscopy enhancve the visualization of the blood vessels and collagen fibers, constituting an additional methodology for this purpose. In the evaluation of plasma extravasation, the product of degradation of ECGG presented values of Evans blue dye extravasation by gram of tissue (0.0514 ± 0.0220 mg / mL) lower to the other tested formulations (p <0.05). It is concluded that the topical formulation based on EGCG developed for endodontic use, presented stable physical and chemical properties and tissue compatibility.
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Elaboration et caractérisation de revêtements composites (Apatite-Alumine) sur métal par projection thermique / Synthesis and characterization of alumina-apatite coatings deposited by atmospheric plasma spraying

Ghorbel-Feki, Halima 12 December 2016 (has links)
A l'heure actuelle les recherches de nouvelles apatites thermiquement plus stables se développent. Ainsi desdépôts à base de fluoroapatite (Ca10(PO4)6F2) ou de fluorhydroxyapatite fournissent des dépôts plus stables etplus adhérents que l'hydroxyaptite tout en étant biocompatibles. La fluoroapatite (Fap) présente non seulement despropriétés physicochimiques semblables à celles de l'os naturel mais également une bonne résistance à lacorrosion dans le milieu physiologique. La Fap et l'hydroxyapatite (Hap) sont utilisées soit sous forme de dépôt surles parties métalliques de prothèses soit toutefois comme matériaux de comblement osseux. L'utilisation de cesbiocéramiques pose quelques problèmes en raison de leur faible tenue mécanique. L'alumine a été proposée ainsipour ses bonnes propriétés mécaniques et pour sa forte affinité pour le fluor avec lequel elle donne des composéstrès stables. Des dépôts composites Al2O3-Fap et Hap-Fap ont été réalisés par projection thermique. Nous avonsfait varier dans ces composites le pourcentage de fluor. Les résultats obtenus montrent que l'ajout de Fap améliorela résistance mécanique et les propriétés tribologiques de l'Hap et contribue à l'adhésion et à la prolifération descellules osseuses pour les dépôts d'alumine. / A considerable amount of research already focused on ceramic biomaterials given their chemical stabilityand high mechanical strength. On the one hand, Fluorapatite (Fa) has recently attracted some attention as analternative to pure hydroxyapatite (Hap) as coating on metallic implants, given its chemical composition which issimilar to the bone mineral and therefore its excellent biocompatibility. On the other hand, alumina is known for itsexcellent bioinertia and is also one of the most widely investigated bioceramics. In this frame, the aim of our workwas to investigate Al2O3-Fap and Hap-Fap composite coatings deposited on stainless steel substrates usingSpraying processes (APS and SHVOF). The mechanical, micro-structural, tribological and biological (in Vitro and inVivo tests) properties of these composite coatings are determined and analysed in order to determine their possibleuse as surigical implant materials.
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Caractérisation physico-chimique et ultrasonore de matériaux céramiques pour applications biomédicales / Physico-chemical and ultrasonic characterization of ceramic materials for biomedical applications

Popa, Cristina Liana 27 September 2016 (has links)
L’hydroxyapatite est l'un des matériaux les plus fréquemment utilisés pour le traitement des maladies des tissus durs. Le zinc est impliqué dans chaque étape du métabolisme du tissu osseux et une carence en zinc peut déterminer l'apparition de l'ostéoporose. Le dopage de l'hydroxyapatite par des ions de zinc peut créer un meilleur matériau, avec des propriétés physico-chimiques supérieures. L'objectif de cette thèse est de créer de nouveaux matériaux biocéramiques avec des propriétés spécifiques qui pourraient permettre le développement de nouvelles applications dans le domaine médical. Une attention particulière a été portée à la caractérisation des propriétés biologiques et physico-chimiques. Dans cette thèse, une nouvelle méthode non destructive de caractérisation de nanoparticules de céramique a été développée. La thèse se compose de six chapitres. Les deux premiers décrivent les biomatériaux et les techniques de caractérisation physico-chimique et ultrasonore utilisées, les trois chapitres suivants présentent des résultats expérimentaux originaux et le dernier chapitre des conclusions générales. La nouveauté de cette étude réside dans la caractérisation de matériaux biocéramiques à base d'hydroxyapatite pour de possibles applications biomédicales. Une nouvelle méthode non destructive de caractérisation par ultrasons est présentée. Ces résultats pourraient contribuer à développer une technique rapide et efficace pour la caractérisation de matériaux céramiques, qui pourrait être utilisée dans le futur en complément des techniques communément utilisées dans le domaine médical, notamment dans le domaine orthopédique. / Hydroxyapatite is one of the most commonly used material used for treating hard tissue diseases. Zinc is involved in each stage of bone tissue metabolism and a lack of it may determine the onset of osteoporosis. Doping hydroxyapatite with Zn ions may cause an improvement of the hydroxyapatite properties, thus resulting a better material, with enhanced physico-chemical properties. Devices based on collagen and hydroxyapatite inhibit the development of bacterial pathogens, reducing the risk of post-surgical infections. The goal of this thesis was to create new bioceramic materials with specific properties which could allow development of new applications in the medical field. Special attention was paid to the characterization of the physico-chemical and biological properties. In this thesis are reported for the first time non-destructive, ultrasonic spectroscopy studies performed on ceramic solutions. The thesis consists of six chapters, the first two comprised of general aspects, the following three chapters present original experimental results and the last chapter presents general conclusions. The novelty of this study lies in the method of synthesis and characterization of bioceramic materials based on hydroxyapatite for possible biomedical applications. Furthermore, a new non-destructive method of characterization techniques based on ultrasounds is presented. The results presented in this study could create a premises of developing a rapid and effective technique for characterization of ceramic materials, which could be used in the future as a complementary technique widely used on different materials used in the medical field, especially in the orthopedic field.
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Azotinių trąšų gamyklos technogeninės taršos paveiktų miško ekosistemų būklės pokyčiai sumažėjus taršai / Changes in the condition of forest ecosystems exposed by technogenic emissions from nitrogen fertilizer plant under reduced pollution

Plaušinytė, Erika 08 December 2014 (has links)
Disertacijoje nagrinėjama technogeninės taršos pažeistų skirtingų miško ekosistemos komponentų (medyno, dirvožemio, krūmokšnių, žolinių augalų ir samanų danga) pokyčiai sumažėjus gamyklos AB „Achema“ taršai. Naudojant 26 metų (1981–2007) ir dabartinių metų (2011–2012) tyrimų duomenis yra atlikta analizė apie skirtingus miško ekosistemos komponentų pokyčius ir įvertinta miško ekosistemų atsikūrimo galimybės. Remiantis tyrimų rezultatais nustatyta, kad praėjus 10–20 metų laikotarpiui nuo gamyklos teršimo pradžios (1979 m.) gali atskurti pažeistos miško ekosistemos. Pirmiausia atsikuria pažeisti medynai, po to – dirvožemio cheminės ir biologinės savybės, vėliausiai – krūmokšnių, žolinių augalų bei samanų danga ir dabartinė ekosistemų būklė yra artima neužterštiems žaliašiliams. Tačiau arčiausiai gamyklos krūmokšnių, žolinių augalų ir samanų dangoje vis dar randami nitrofiliniai augalai, kurie nebūdingi neužterštiems žaliašiliams. Tai rodo, kad dėl medyno struktūros negrįžtamumo prie AB „Achema“ krūmokšnių, žolinių augalų ir samanų danga išlieka pakitusi. / Doctoral dissertation presents the restoration of various components of forest ecosystem (stand, soil, the cover of brush, herbaceous vegetation and mosses) after the reduction of air pollution from the plant of fertilizers Achema. Using study data of 26 years (1981–2007) and of the current year (2011-2012), an analysis of the changes of different components of forest ecosystems has been carried out and recovery possibilities of forest ecosystems were evaluated. Based on the survey results it was found that after 10–20 years since the beginning of pollution from the factory (1979) damaged forest ecosystems are able to recover. First of all recover damaged stands, then – chemical and biological soil properties, at the latest – the cover of shrubs, herbaceous plants and mosses, and the current state of forest ecosystems is similar to control pine stands. However, ground vegetation in the nearest to the factory sites still contains nitrophilous plants which are not typical for uncontaminated pine forests. This shows that due to the irreversibility of the structure of stands near Achema, the cover of shrubs, herbaceous plants and mosses remains altered.
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Phase separated borosilicate glasses for dental applications : mixture design in relation with the ion release in acid condition and microstructure / Verres borosilicatés à séparation de phase pour applications dentaires : formulation de la composition en relation avec la dissolution des ions en milieu acide et la microstructure

Lizzi, Federico 02 May 2018 (has links)
La recherche de matériaux dentaires efficaces est une préoccupation constante de toute l'histoire de la dentisterie. Avec l'émergence de meilleurs produits, le développement de matériaux toujours plus innovants s'est imposé. De plus, la combinaison de différentes sciences comme la chimie, la biologie, la physique et l'ingénierie a permis de mieux connaître les exigences liées à la restauration dentaire. Le projet BIODENSOL est un projet de recherche et de mobilité doctorale entre l'Université de Lyon et LUCIDEON Ltd (Stoke-on- Trent, Royaume-Uni), financé par la Commission européenne. Le projet a été conçu pour favoriser les relations entre la recherche académique et les applications commerciales, pour améliorer les innovations médicales et associer des chimistes de l'état solide avec des praticiens hospitaliers en contact direct avec les patients ayant des problèmes dentaires. Ce projet proposait trois thèses de doctorat permettant de répondre aux conséquences des caries et d'érosion de l'émail par les aliments acides, l'idée de base étant de favoriser la reminéralisation pour éviter ces problèmes. Les recherches ont évolué de manière indépendante selon trois voies distinctes examinant trois matériaux différents qui pourraient amener des solutions potentielles. Le sujet principal de cette thèse concerne l'étude de poudres de verre borosilicaté présentant une séparation de phases et pouvant être incorporées dans des ciments verre ionomères. Les verres borosilicatés sont des matériaux prometteurs qui ont été largement étudiés pour des applications biomédicales, comme par exemple les échafaudages dans les tissus mous où la réparation osseuse. Par analogie avec les verres silicatés développés par Hench en 1969, qui sont reconnus pour leur bioactivité et leurs propriétés antimicrobiennes, les verres borosilicatés pourraient intéresser la dentisterie. Le système de verre étudié ici est un verre basé sur l'association de 5 constituants, SiO2-K2O-B2O3-CaO-Al2O3, qui a une forte tendance à la séparation des phases. L'objectif de ce travail est d'élaborer par fusion/trempe puis caractériser une série de nouvelles formulations de verres borosilicatés, puis de comprendre le mécanisme et la cinétique de dissolution en relation avec leur microstructure et leur composition. La variation des proportions de chaque constituant est déterminée par l'approche des plans d'expérience. L'utilisation d'un traitement thermique pour favoriser la séparation des phases en vue d'influencer le taux de libération cationique a été spécialement étudiée. Le processus de dissolution des borosilicates dans une solution aqueuse neutre (fluide corporel simulé) ou dans une solution acide (simulant des scénarios où des bactéries ou des aliments acides sont présents) fournit des informations sur le type et la concentration des espèces libérées par le verre. Différentes compositions ont été étudiées dans lesquelles SiO2 et K2O sont fixés tandis que les autres éléments varient afin d'évaluer l'effet sur la séparation de phases. Les cinétiques de dissolution des ions B-, Si-, Ca-, K- et Al- peuvent alors être reliées à la chimie du verre et à la microstructure. La séparation de phases amorphes (APS) provoque la séparation d'une phase unique initialement homogène en deux phases ou plus de compositions différentes. Le degré d'interconnectivité des deux phases vitreuses dépend de la nature du mécanisme de séparation de phases. Les verres élaborés sont optiquement transparents, puis deviennent plus ou moins opalescents suite à un traitement thermique. Le degré d'opacité est clairement dépendant de la proportion des éléments entrant dans la composition du verre. Le schéma de la libération d'ions implique que l'une des phases est plus réactive et sensible à l'attaque ; elle sera dissoute plus rapidement du verre... [etc] / The research for efficient dental materials has been a constant throughout the history of dentistry. As better materials emerged, the development of ever more innovative materials has been pushed forward. Moreover the combination of different sciences such as chemistry, biology, physics and engineering has provided better knowledge to the demanding requirements of the dental restorations. The BIODENSOL project is a European commission funded mobility research project managed by the University of Lyon and LUCIDEON Ltd, Stoke-on-Trent, UK. The project is designed to help building relations between academic and commercial research to enhance medical innovations and associates solid state chemists and hospital practicioners in direct contact with the patients with dental problems. This project proposes three PhD studies to address the problems of caries and enamel erosion by acidic foods (leading to sensitive teeth) encouraging re-mineralization to help avoid these problems. The researches independently evolved in three different routes investigating three different materials that could provide potential solutions. The main objective of this thesis concerns the study of Borosilicate phase separated glass powders for glass ionomer cements. As silicate bioglasses developed by Hench in 1969, regarding their bioactivity and antimicrobial properties, borosilicates glasses are promising materials and have been widely studied for biomedical applications for scaffolds in soft tissues and for bone repair and could be of interest in dentistry. The glass system studied here is a borosilicate glass (SiO2-K2O-B2O3-CaO-Al2O3) with a strong tendency to phase separate. The objective of this work is to characterize a series of the novel borosilicate formulations and to understand the mechanism and kinetic of dissolution related to their microstructure and composition. The use of thermal treatment to promote phase separation as a means of influencing the rate of ion leaching was especially studied. The dissolution process of borosilicates in neutral body solution (simulating body fluid) or in acid solution (simulating scenarios where bacteria or acid foods are present) provides information regarding the type and concentration of species released by the glass. Different compositions have been investigated in which SiO2 and K2O are fixed while the other elements are varied in order to assess the effect on the phase separation. As the novel borosilicates produced with the meltquenching technique is immersed in an aqueous environment, B-, Si-, Ca-, K- and Al- species are released to different degrees as a function of the time. Ion leaching trends can be related to the glass chemistry and microstructure. It has been shown that the amorphous phase separation (APS) causes an initially homogeneous single phase to separate into two or more phases of different compositions. The degree of interconnectivity of the two glass phases depend on the nature of the phase separation mechanism. This process can occur by a nucleation and growth process which gives isolated spherical particles or by spinodal decomposition where an interconnected structure is obtained. It is significant that before a heat-treatment the glasses are optically clear, but turn opalescent to different degrees following a heat treatment depending on the wt% of the elements in the composition. The pattern of the ion release implies that one of the phases is more reactive and susceptible to acid attack and will be leached out from the glass earlier. The other phase will remain in the cement improving the mechanical properties of the dental restorative material. Moreover, the mixing of the glass powder with a commercial poly(acrylic acid) has shown interesting mechanical and bioactive properties. This work showed how the ions leaching are influenced by the glass composition and the heat-treatment... [etc]

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