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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.
71

Metacognitive locale : a design-based theory of students' metacognitive language and networking in mathematics / Divan Jagals

Jagals, Divan January 2015 (has links)
The purpose of this study was to design a local theory explaining the relationship between metacognitive language and networks as constructs of a local instructional theory in the context of a fourth-year intermediate phase mathematics education methodology module. The local instructional theory was designed to facilitate an adapted lesson study through a problem-based learning instructional philosophy. A problem-based learning task was then designed outlining the education needs and resources of a South African primary school, characteristic of schools in a rural area. In particular the task describes a fictitious teacher’s concern for teaching a Grade 6 mathematics class the concept of place value. Two groups of students, who volunteered to participate in this research, collaboratively designed and presented research lessons across two educational design-based research cycles for two rural schools in North West, as a form of service learning. In implementing the local instructional theory phases, participants were required to follow the lesson study approach by investigating, planning, developing, presenting, reflecting, refining and re-presenting the research lesson and its resources. These design sessions were videorecorded, transcribed and then coded in Atlas.ti through interpretivistic and hermeneutic analysis. The coded data were then imported into NodeXL to illustrate embedded networks. Not only social network data but also metacognitive network data were visualised in terms of metacognitive networks. The results show that across the local instructional theory phases, constructs of metacognition, metacognitive language and networking emerged on a social (stratum 1), interpersonal (stratum 2) and social-metacognitive (stratum 3) level. Collectively, these strata form the architecture of the theory of metacognitive locale that explains the relationship between the constructs. The findings suggest that when students express their metacognitive processes through a metacognitive language (e.g. I am thinking or feeling), their interpersonal metacognitive networks develop into shared metacognitive experiences which foster their metacognitive locale, a dimension of their metacognitive language and networking. / PhD (Mathematics Education), North-West University, Potchefstroom Campus, 2015
72

Metacognitive locale : a design-based theory of students' metacognitive language and networking in mathematics / Divan Jagals

Jagals, Divan January 2015 (has links)
The purpose of this study was to design a local theory explaining the relationship between metacognitive language and networks as constructs of a local instructional theory in the context of a fourth-year intermediate phase mathematics education methodology module. The local instructional theory was designed to facilitate an adapted lesson study through a problem-based learning instructional philosophy. A problem-based learning task was then designed outlining the education needs and resources of a South African primary school, characteristic of schools in a rural area. In particular the task describes a fictitious teacher’s concern for teaching a Grade 6 mathematics class the concept of place value. Two groups of students, who volunteered to participate in this research, collaboratively designed and presented research lessons across two educational design-based research cycles for two rural schools in North West, as a form of service learning. In implementing the local instructional theory phases, participants were required to follow the lesson study approach by investigating, planning, developing, presenting, reflecting, refining and re-presenting the research lesson and its resources. These design sessions were videorecorded, transcribed and then coded in Atlas.ti through interpretivistic and hermeneutic analysis. The coded data were then imported into NodeXL to illustrate embedded networks. Not only social network data but also metacognitive network data were visualised in terms of metacognitive networks. The results show that across the local instructional theory phases, constructs of metacognition, metacognitive language and networking emerged on a social (stratum 1), interpersonal (stratum 2) and social-metacognitive (stratum 3) level. Collectively, these strata form the architecture of the theory of metacognitive locale that explains the relationship between the constructs. The findings suggest that when students express their metacognitive processes through a metacognitive language (e.g. I am thinking or feeling), their interpersonal metacognitive networks develop into shared metacognitive experiences which foster their metacognitive locale, a dimension of their metacognitive language and networking. / PhD (Mathematics Education), North-West University, Potchefstroom Campus, 2015
73

Origamis et groupes de permutation / Origamis and permutation groups

Zmiaikou, David 08 September 2011 (has links)
Un origami est un revêtement du tore T2, éventuellement ramifié au-dessus de l'origine.Cet objet a été introduit par William P. Thurston et William A. Veech dans les années 1970.Un origami peut être vu comme un ensemble fini de copies du carreau unitaire qui sont collées par translations. Ainsi, un origami est un cas particulier d'une surface de translation,un élément de l'espace des modules de surfaces de Riemann munies d'une 1-forme holomorphe.Un origami O avec n carreaux correspond à une paire de permutations (σ, τ ) Є 2 Sn X Sn définie à conjugaison près. Le groupe Mon(O) engendré par une telle paire s'appelle le groupe de monodromie de O. On dit qu'un origami est primitif si son groupe de monodromie est un groupe de permutation primitif. Il y a une action naturelle du groupeGL2(Z) sur les origamis, le stabilisateur de O pour cette action est le groupe de Veechdésigné par GL(O). Le groupe de monodromie est un invariant des GL2(Z)-orbites.Dans le chapitre 3 de la thèse, nous montrons que le groupe de monodromie de tout origami primitif à n carreaux dans la strate H(2k) est An ou Sn si n ≥ 3k + 2, et noustrouvons la borne exacte quand 2k + 1 est premier. La même proposition est vraie pourla strate H(1; 1) si n =/= 6. Dans le chapitre 4, nous considérons les origamis réguliers,i.e. ceux pour lesquels le nombre de carreaux est égal à l'ordre du groupe de monodromie.Nous construisons de nouvelles familles d'origamis intéressantes et cherchons leurs strates et groupes de Veech. Nous estimons également le nombre de GL2(Z)-orbites et strates distinctes des origamis réguliers ayant un groupe de monodromie donné. Afin de trouver une borne inférieure pour les origamis alternés, nous prouvons que chaque permutation dans An quifixe peu de points est le commutateur d'une paire engendrant An. Dans le chapitre 6, nous étudions une propriété de sous-groupes de PSL2(Z) qui est liée à la propriété d'être le groupe de Veech d'un origami. / An origami is a covering of the torus T2, possibly ramified above the origin. This objectwas introduced by William P. Thurston and William A. Veech in 1970s. Un origami can beviewed as a finite collection of copies of the unitary square that are glued by translations.Thus, un origami is a particular case of a translation surface, that is, an element of the moduli space of Riemann surfaces equipped with a holomorphic 1-form.An n-square origami O corresponds to a pair of permutations (σ, τ ) Є 2 Sn X Sn defined up to conjugation. The group Mon(O) generated by such a pair is called the monodromy group of O. We say that an origami is primitive if its monodromy group is a primitive permutation group. There is a natural action of group GL2(Z) on the origamis, the stabilizer of O for this action is the Veech group denoted by GL(O). The monodromy group is aninvariant of the GL2(Z)-orbits.In the chapter 3 of the thesis, we show that the monodromy group of any primitive n-square origami in the stratum H(2k) is either An or Sn if n ≥ 3k + 2, and we find the exact bound when 2k + 1 is prime. The same proposition is true for the stratum H(1; 1) if n =/= 6.In the chapter 4, we consider the regular origamis, i.e. the origamis for which the number of squares equals the order of the monodromy group. We construct new families of origamis and investigate their strata and Veech groups. Also, we estimate the number of distinct GL2(Z)-orbits and strata of regular origamis with a given monodromy group. In order to find a lower bound for alternating origamis, we prove that each permutation in An which fixes few points is the commutator of a pair generating An. In the chapter 6, we study a subgroup property of PSL2(Z) that is related to the property to be the Veech group of an origami.
74

Regime de distúrbio e dinâmica da regeneração natural na Floresta Pluvial Atlântica Submontana / Disturbance regime and natural regeneration dynamics in the Lower Montane Atlantic Rain Forest

Lima, Renato Augusto Ferreira de 19 April 2007 (has links)
Em uma parcela permanente de 10,24 ha na Floresta Pluvial Atlântica Submontana do Parque Estadual Carlos Botelho (Sete Barras, SP, Brasil), este estudo teve o intuito de descrever o regime de distúrbio do dossel e avaliar a regeneração natural sob diferentes regimes de luz. Para tanto, foi realizado o levantamento de todas as clareiras da parcela, que foram mensuradas e tiveram sua idade aproximada estimada. Em seguida, foram instaladas 42 parcelas de 10x10m para avaliar a regeneração natural em três regimes luminosos: dossel contínuo (18 parcelas), clareiras pequenas a médias (11) e clareiras grandes com abundância de Guadua tagoara (Nees) Kunth (13). O regime de luz foi caracterizado por fotografias hemisféricas tomadas ao centro das parcelas. O estudo da regeneração natural foi divido em: estrato herbáceo (i.e., ervas menores que um metro de altura), avaliado através da cobertura do solo estimada pelo método de interceptação de linha; e estrato arbustivo, avaliado através dos indivíduos com altura maior que 1m, e com diâmetro à altura do peito menor que 5cm. Para estes indivíduos anotou-se a espécie, diâmetro, altura total e área de copa, além da presença de partes reprodutivas e substrato de germinação. Informações sobre hábito, grupo sucessional e síndrome de dispersão das espécies também foram obtidas. Após um ano, uma reavaliação permitiu analisar a mortalidade, danos, recrutamento e crescimento. Apesar de 67% das clareiras terem sido menores que 150 m2 , o regime de distúrbio foi atípico, principalmente pela contribuição de clareiras maiores que 750 m2 , e pela área média e total que variaram respectivamente de 419 a 799 m2 , e de 26 a 49%, dependendo do método de delimitação de clareira. A densidade foi de 6 clareiras.ha -1 e a taxa de recorrência variou entre 91 e 220 anos, dependendo dos métodos. Houve diferença significativa entre os ambientes para a maioria dos índices de luz, especialmente para a radiação total incidente com médias entre 909 e 2.400 mols.m-2.ano-1. Observou-se diferença significativa entre ambientes na cobertura por ervas, porém os resultados variaram entre espécies. No estrato arbustivo, houve diferença significativa na composição e abundância das espécies, inclusive entre clareiras médias e sub-bosque. A densidade de ervas e arbustos foi maior nos ambientes mais iluminados, assim como a densidade de pioneiras e secundárias iniciais. O recrutamento em um ano (16%) apresentou diferenças nos ambientes, com 63% dos recrutas apenas nas grandes clareiras. O mesmo não ocorreu com a taxa de mortalidade cujas principais causas foram os danos físicos e dessecamento. Para os 13% de indivíduos danificados em um ano, houve destaque para danos ligados à extração de palmito. Apenas os danos físicos naturais apresentaram diferença entre ambientes, com grandes clareiras sendo as mais danosas. No geral e entre as 25 espécies avaliadas separadamente, houve uma tendência de crescimento maior com o aumento da incidência luminosa. Clareiras pequenas a médias tiveram significativamente maior riqueza, diversidade e menor dominância de espécies que o sub-bosque. Clareiras grandes com bambu tiveram menor riqueza e diversidade, mas contribuíram com a manutenção da diversidade beta da parcela permanente. / In a 10.24 ha permanent plot of Tropical Lower Montane Atlantic Rain Forest in the Carlos Botelho State Park (Sete Barras, SP, Brazil), this study aimed to describe the canopy disturbance regime and to assess natural regeneration under different light regimes. In order to do so, the plot was completely surveyed for canopy gaps that were measured and had their approximate age estimated. Then, 42 10x10 m plots were established to evaluate natural regeneration under three light regimes: understory (18 plots), small to medium canopy gaps (11 plots) and large gaps abundant in Guadua tagoara (Nees) Kunth (13 plots). The light regime was characterized through hemispherical photographs taken at each plot center. Natural regeneration was dived into: herb stratum (i.e., herbs below one meter in height) assessed through soil coverage using the line intercept method; and shrub stratum or all plant individuals taller than one meter high and thinner than 5 cm in diameter at breast height. All individuals were identified to species and measured for diameter, height, crown height and area, besides notes on the presence of reproductive structures and germination substrate. Information on growth form, dispersal syndrome and ecological group were also obtained for each species. After one year, one reevaluation was made to assess mortality, damages, recruitment and growth. Although 67% of gaps were smaller than 150 m2 , the plot disturbance regime was atypical mainly by the contribution of gaps bigger than 750 m2 and by the average and total gap area that varied respectively from 419 to 799 m2 , and from 26 to 49% depending on the gap delimitation method. Gap density was 6 gaps.ha-1 and the turnover rate varied from 91 to 220 years depending on the gap method employed. There was significant difference between environments among the light index, especially for total incident radiation with means varying from 909 and 2,400 mols.m-2.y-1. It was found significant differences on herb soil coverage between environments, although the results varied among species. In the shrub stratum, species composition and abundance was significantly different, even between small to medium canopy gaps and the understorey. Herb and shrub densities were bigger in the more enlightened environments, as well as pioneer and early secondary species densities. Recruitment over the year (16%) was different between environments with large gaps accounting for 63% of all recruits. Similar difference was not found for mortality rate that had physical damage and desiccation as main death causes. Amid the 13% of damage individuals in the course of one year, there was noticeable contribution of damages linked to illegal extraction of palm-heart. Differences between environments were present only for physical damages with large gaps being the most damaging environment. In general and among the 25 species evaluated separately, there was a tendency of bigger growth with enhancement in light incidence. Small to medium gaps had significantly higher species richness and diversity, and lower dominance compared to the understorey. Large gaps had lower richness and diversity, but they contributed to maintain beta diversity of the permanent plot.
75

Coated microneedles and microdermabrasion for transdermal delivery

Gill, Harvinder Singh 09 July 2007 (has links)
The major hurdle in the development of transdermal route as a versatile drug delivery method is the formidable transport barrier provided by the stratum corneum. Despite decades of research to overcome the stratum corneum barrier, limited success has been achieved. The objectives of this research were to develop and characterize two different strategies to overcome the stratum corneum barrier for transdermal delivery of biopharmaceuticals and vaccines. In the first strategy, coated microneedles (sharp-tipped, micron-sized structures) were developed to enable delivery of drugs directly into the skin by bypassing the stratum corneum barrier. In the second strategy, instead of bypassing the barrier, microdermabrasion was used to selectively abrade stratum corneum with sharp microparticles for topical drug application. Coated microneedles For developing painless microneedles, the first detailed study was performed to characterize the effect of microneedle geometry on pain caused by microneedle insertions in human volunteers. This study demonstrated that microneedles are significantly less painful than a 26-gage hypodermic needle and that decreasing microneedle length and numbers reduces pain. Next, the first in-depth study of microneedle coating methods and formulations was performed to (i) develop a novel micron-scale dip-coating process, (ii) test the breadth of compounds that can be coated onto microneedles, and (iii) develop a rational basis to design novel coating formulations based on the physics of dip-coating. Finally, a plasmid DNA-vaccine was coated onto microneedles to immunize mice, to provide the first evidence that microneedle-based skin immunization can generate a robust in vivo antigen-specific cytotoxic-T-lymphocyte response using similar, or lower, DNA doses on microneedles as when using the gene gun or intramuscular injection. Microdermabrasion We demonstrated for the first time that microdermabrasion in monkeys and humans can selectively, yet completely remove the stratum corneum layer. Using a mobile mode of microdermabrasion, an increase in the number of treatment passes led to greater tissue removal. Furthermore, topical application of Modified Vaccinia Ankara virus after microdermabrasion induced virus-specific antibodies in monkeys. In conclusion, both coated microneedles and microdermabrasion were developed to enable delivery of biomolecules into the skin, indicating their potential for transdermal delivery of a wide range of biopharmaceuticals and vaccines.
76

Regime de distúrbio e dinâmica da regeneração natural na Floresta Pluvial Atlântica Submontana / Disturbance regime and natural regeneration dynamics in the Lower Montane Atlantic Rain Forest

Renato Augusto Ferreira de Lima 19 April 2007 (has links)
Em uma parcela permanente de 10,24 ha na Floresta Pluvial Atlântica Submontana do Parque Estadual Carlos Botelho (Sete Barras, SP, Brasil), este estudo teve o intuito de descrever o regime de distúrbio do dossel e avaliar a regeneração natural sob diferentes regimes de luz. Para tanto, foi realizado o levantamento de todas as clareiras da parcela, que foram mensuradas e tiveram sua idade aproximada estimada. Em seguida, foram instaladas 42 parcelas de 10x10m para avaliar a regeneração natural em três regimes luminosos: dossel contínuo (18 parcelas), clareiras pequenas a médias (11) e clareiras grandes com abundância de Guadua tagoara (Nees) Kunth (13). O regime de luz foi caracterizado por fotografias hemisféricas tomadas ao centro das parcelas. O estudo da regeneração natural foi divido em: estrato herbáceo (i.e., ervas menores que um metro de altura), avaliado através da cobertura do solo estimada pelo método de interceptação de linha; e estrato arbustivo, avaliado através dos indivíduos com altura maior que 1m, e com diâmetro à altura do peito menor que 5cm. Para estes indivíduos anotou-se a espécie, diâmetro, altura total e área de copa, além da presença de partes reprodutivas e substrato de germinação. Informações sobre hábito, grupo sucessional e síndrome de dispersão das espécies também foram obtidas. Após um ano, uma reavaliação permitiu analisar a mortalidade, danos, recrutamento e crescimento. Apesar de 67% das clareiras terem sido menores que 150 m2 , o regime de distúrbio foi atípico, principalmente pela contribuição de clareiras maiores que 750 m2 , e pela área média e total que variaram respectivamente de 419 a 799 m2 , e de 26 a 49%, dependendo do método de delimitação de clareira. A densidade foi de 6 clareiras.ha -1 e a taxa de recorrência variou entre 91 e 220 anos, dependendo dos métodos. Houve diferença significativa entre os ambientes para a maioria dos índices de luz, especialmente para a radiação total incidente com médias entre 909 e 2.400 mols.m-2.ano-1. Observou-se diferença significativa entre ambientes na cobertura por ervas, porém os resultados variaram entre espécies. No estrato arbustivo, houve diferença significativa na composição e abundância das espécies, inclusive entre clareiras médias e sub-bosque. A densidade de ervas e arbustos foi maior nos ambientes mais iluminados, assim como a densidade de pioneiras e secundárias iniciais. O recrutamento em um ano (16%) apresentou diferenças nos ambientes, com 63% dos recrutas apenas nas grandes clareiras. O mesmo não ocorreu com a taxa de mortalidade cujas principais causas foram os danos físicos e dessecamento. Para os 13% de indivíduos danificados em um ano, houve destaque para danos ligados à extração de palmito. Apenas os danos físicos naturais apresentaram diferença entre ambientes, com grandes clareiras sendo as mais danosas. No geral e entre as 25 espécies avaliadas separadamente, houve uma tendência de crescimento maior com o aumento da incidência luminosa. Clareiras pequenas a médias tiveram significativamente maior riqueza, diversidade e menor dominância de espécies que o sub-bosque. Clareiras grandes com bambu tiveram menor riqueza e diversidade, mas contribuíram com a manutenção da diversidade beta da parcela permanente. / In a 10.24 ha permanent plot of Tropical Lower Montane Atlantic Rain Forest in the Carlos Botelho State Park (Sete Barras, SP, Brazil), this study aimed to describe the canopy disturbance regime and to assess natural regeneration under different light regimes. In order to do so, the plot was completely surveyed for canopy gaps that were measured and had their approximate age estimated. Then, 42 10x10 m plots were established to evaluate natural regeneration under three light regimes: understory (18 plots), small to medium canopy gaps (11 plots) and large gaps abundant in Guadua tagoara (Nees) Kunth (13 plots). The light regime was characterized through hemispherical photographs taken at each plot center. Natural regeneration was dived into: herb stratum (i.e., herbs below one meter in height) assessed through soil coverage using the line intercept method; and shrub stratum or all plant individuals taller than one meter high and thinner than 5 cm in diameter at breast height. All individuals were identified to species and measured for diameter, height, crown height and area, besides notes on the presence of reproductive structures and germination substrate. Information on growth form, dispersal syndrome and ecological group were also obtained for each species. After one year, one reevaluation was made to assess mortality, damages, recruitment and growth. Although 67% of gaps were smaller than 150 m2 , the plot disturbance regime was atypical mainly by the contribution of gaps bigger than 750 m2 and by the average and total gap area that varied respectively from 419 to 799 m2 , and from 26 to 49% depending on the gap delimitation method. Gap density was 6 gaps.ha-1 and the turnover rate varied from 91 to 220 years depending on the gap method employed. There was significant difference between environments among the light index, especially for total incident radiation with means varying from 909 and 2,400 mols.m-2.y-1. It was found significant differences on herb soil coverage between environments, although the results varied among species. In the shrub stratum, species composition and abundance was significantly different, even between small to medium canopy gaps and the understorey. Herb and shrub densities were bigger in the more enlightened environments, as well as pioneer and early secondary species densities. Recruitment over the year (16%) was different between environments with large gaps accounting for 63% of all recruits. Similar difference was not found for mortality rate that had physical damage and desiccation as main death causes. Amid the 13% of damage individuals in the course of one year, there was noticeable contribution of damages linked to illegal extraction of palm-heart. Differences between environments were present only for physical damages with large gaps being the most damaging environment. In general and among the 25 species evaluated separately, there was a tendency of bigger growth with enhancement in light incidence. Small to medium gaps had significantly higher species richness and diversity, and lower dominance compared to the understorey. Large gaps had lower richness and diversity, but they contributed to maintain beta diversity of the permanent plot.
77

Estudo da formação de microemulsões contendo óleo essencial de Citrus sinensis (L.) Osbeck : efeito dos co-tensoativos e avaliação da interação das microemulsões com modelo de estrato córneo

Resende, Quênnia Garcia Moreno 13 November 2013 (has links)
Microemulsions (MEs) are dispersed systems, thermodynamically stable, isotropic, transparent, and stabilized by an interfacial film of surfactant compounds. In this study were obtained MEs from differents co - surfactant (ethanol - ET, isopropanol-ISO and propylene glycol - PG), Citrus sinensis (L.) Osbeck essential oil (CSEO), Tween 80 ® and phosphate buffer (pH 5.0). The co - surfactants were selected because they are tolerated by the skin. Therefore, the aim of the study was to evaluate the influence of co - surfactants in the formation of MEs containing Tween 80, CSEO and evaluate the influence of nifedipine (NFD) in the structure of systems formed. The MEs were obtained by constructing diagrams of pseudo-ternary phase in order to evaluate the influence of co-surfactant in the formation of MEs. The structural characterization of these systems was obtained by Polarized Light Microscopy (MLP), test electrical conductivity and Small angle X-ray scattering (SAXS). In each diagram, two formulations were selected, which was the criterion sense phase, in the O / A and bicontinuous, in which the NFD is incorporated. The formulations were evaluated by the techniques mentioned, to observe the influence of NFD and characterized by pH, droplet size, polydispersity index (PDI), surface tension and rheology. Interaction studies with model stratum corneum (SC) were performed using the techniques of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). In the diagrams showed the greatest formation region of the MEs to the ISO (above 40 % T / Cot) instead of the co- surfactants ET and PG. When assessing the electrical conductivity has been observed that increasing the aqueous fraction resulted in an increase in conductivity. The SAXS curves demonstrated that all systems are characteristic of micellar structures and as the water content was added, it was observed the formation of larger structures. Therefore, from the results obtained, the NFD has been incorporated in the formulations selected. The MEs presented as stable systems, isotropic, translucent droplet size between 16 and 34 nm, PDI below 0.5 and pH in the range of 5.64 to 6.7, compatible with the skin and pH stability of the NFD. In conductivity tests for each co - surfactant, the MEs were classified as bicontinuous and O / A. The MEs exhibited reduced surface tension and the formulations containing ISO submitted a surface tension value (24,764 mN / m) lower than the other co - surfactants (ET - 29.512 mN/m PG - 31.784 mN/m), confirmed by the evaluation of the droplet diameter and obtaining the phase diagram. The MEs exhibited Newtonian behavior, with consistency indices (k) higher in formulations with higher proportions of T / Cot, result corroborated the structures observed by SAXS. The DSC and FTIR techniques have demonstrated the use of the MEs as permeation promoters, provided from interactions with SC model. Therefore, the diagrams have elucidated the effect of co- surfactant in the formation of MEs and the same interference suffered no NFD, suggesting their use as permeation enhancers on the skin on application. / As microemulsões (MEs) são sistemas dispersos, termodinamicamente estáveis, isotrópicos, transparentes, estabilizados por um filme interfacial de compostos tensoativos. Neste trabalho foram obtidas MEs a partir de diferentes co-tensoativos (etanol-ET, isopropanol-ISO e propilenoglicol-PG), óleo essencial de Citrus sinensis (L.) Osbeck (OECS), Tween 80® e tampão fosfato (pH 5.0). Os co-tensoativos foram selecionados por serem toleráveis pela pele. Assim, o objetivo deste trabalho foi avaliar a influência dos co-tensoativos na formação de MEs contendo Tween 80, OECS bem como avaliar a influência da nifedipina (NFD) na estrutura dos sistemas formados. As MEs foram obtidas pela construção de diagramas de fase pseudoternário com o propósito de avaliar a influência do co-tensoativo na zona de formação das MEs. A caracterização estrutural desses sistemas foi realizada por Microscopia de Luz Polarizada (MLP), ensaios de condutividade elétrica e espalhamento de raios-X a baixo ângulo (SAXS). De cada diagrama, foram selecionadas duas formulações, cujo critério foi o sentido de fases, na região de óleo-água (O/A) e bicontínuas, nas quais a NFD foi incorporada. As formulações foram reavaliadas pelas técnicas citadas, a fim de observar a influência da NFD, além de caracterizadas por pH, tamanho de gotícula, índice de polidispersividade (IPD), tensão superficial e reologia. Estudos de interação com modelo de estrato córneo (EC) foram realizados através das técnicas de Calorimetria exploratória diferencial (DSC) e Espectroscopia na região de infravermelho com transformada de Fourier (FTIR). Nos diagramas foi observada uma maior região de formação das MEs para o ISO (acima de 40% de T/Cot) ao contrário dos co-tensoativos ET e PG. Ao avaliar a condutividade elétrica foi observado que o aumento da fração aquosa proporcionou um aumento na condutividade. As curvas de SAXS demonstraram que todos os sistemas foram característicos de estruturas micelares e à medida que o conteúdo aquoso foi adicionado, observou-se a formação de estruturas com maiores dimensões. Logo, a partir dos resultados obtidos, a NFD foi incorporada nas formulações selecionadas. As MEs apresentaram-se como sistemas estáveis, isotrópicos, translúcidos, tamanho de gotículas entre 16 e 34 nm, IPD abaixo de 0,5 e pH na faixa de 5,64 a 6,07, compatíveis com a pele e pH de estabilidade da NFD. Nos ensaios de condutividade para cada co-tensoativo, as MEs foram classificadas como bicontínuas e O/A. As MEs apresentaram redução da tensão superficial, sendo que as formulações contendo ISO apresentaram um valor de tensão (24,764 mN/m) inferior aos demais co-tensoativos (ET- 29,512 mN/m e PG- 31,784 mN/m), confirmado pela avaliação do diâmetro de gotas e obtenção do diagrama de fases. As MEs apresentaram comportamento newtoniano, com os índices de consistência (k) maiores nas formulações com proporções mais elevadas de T/Cot, resultado que corroborou com as estruturas observadas por SAXS. As técnicas de DSC e FTIR demonstraram a utilização das MEs como promotores de permeação, a partir das interações proporcionadas com modelo de EC. Logo, os diagramas elucidaram a influência do co-tensoativo na área de formação de MEs e os mesmos não sofreram interferência da NFD, sugerindo a sua utilização como promotores de permeação em aplicação sobre a pele.
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Mata ciliar em processo de recuperação no baixo Rio São Francisco : florística e fitossociologia / Riparian forest in recovery process in the lower São Francisco River : floristic and phytosociology

Matos, Gilda Maria do Amarante 31 August 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In the state of Sergipe, few floristic and phytosociological studies have been conducted in areas of Riparian Forest. This study was conducted in order to characterize the floristic composition and phytosociological structure of a plant community in riparian area during recovery process, at Mother Nature Farm in Santana de São Francisco - Sergipe. The vegetation object of study is the result of a pilot project that used heterogeneous planting of native tree species, which aimed to obtain data to support future models of restoration in riparian degraded areas in the Lower São Francisco River region. Therefore, there was soil analysis in the area for comparison with ground data performed at the time of implementation of the initial project, floristic and phytosociological survey, with the analysis of horizontal and vertical structure, diversity index of Shannon-Weaver (H '), evenness index Peilou (J'), canopy cover (CC), floristic similarity and dispersion and successional groups syndrome. For phytosociological study of the shrubby- arboreous stratum was conducted a census of individuals present in an area of 1.66 ha, where we sampled all living individuals with bole girth at the level of 1.30 cm (CAP) ≥ 6 cm. The floristic survey of the area for all habits had total richness of 165 species, 133 genera and 51 families, with predominance of herbaceous species, represented by 44.8% of the identified species. Herbaceous families with the highest species richness were Malvaceae (16.7%), Cyperaceae (13.7%), Asteraceae (11%), Fabaceae (8.2%) Poaceae (6.8%), which together represent 56.4% of the richness in herbaceous species recorded in the area. A total 1640 individuals were sampled, belonging to 52 species, 44 genera and 20 families. Through the survey of the natural regeneration of shrub and tree species in the area, were identified individuals belonging to 70 species (38.6% and 61.4% shrubs trees), 58 genera and 25 families. Of these 70 species sampled, 57 species were not derived from planting and thus from the natural regeneration duct through dispersion. With respect the absolute density estimated was 1,025 ha-1 subjects with basal area of 9.79 m2 / ha, average individual diameter of 6.53 cm and average height of 5.65 m. Families who contributed to this floristic richness were Fabaceae, with 17 species, Anacardiaceae with five species, Rubiaceae with four species, Euphorbiaceae and Myrtaceae with three each, Capparaceae, Meliaceae, Polygonaceae, Salicaceae and Sapindaceae with two species each, the remaining families presented only one species each. The species Mimosa caesalpiniifolia Benth. with 2,70 m2 of basal area was the one with the highest values in all phytosociological parameters analyzed, a fact that may indicate a greater adaptation of species to the environment or ecological dominance of this kind. The diversity index Shannon-Wiener (H ') for sampling with 1.640 individuals was 2.78 nats / ind., the evenness index of evenness (J') of 0.70, Jentsch mix coefficient was 0.032 and Simpson's dominance index found was 0.135. The area has a high diversity of species and high dominance. The species in the study area were grouped into three categories dispersion (zoochorous, anemochoric and autochorous) and two series of categories (pioneer and climax). From these ratings was obtained 31 species (59.62%) classified as zoochorous, with 18 pioneer and 13 climax; 15 autochorous species (28.85%), with 12 pioneer and 3 climax; six anemochoric (11.54%), four pioneers and two climax. Independently of analyzed and compared physiognomy, there was a low floristic similarity with other areas of the region. Therefore, all analyzed areas are defined floristic peculiarities. It is also observed that, over the years, recomposing the soil fertility is probably due to increased nutrient cycling and also for vegetation cover which promotes a greater protection of the soil, thereby facilitating the establishment of new species in the area. / Em Sergipe, poucos estudos florísticos e fitossociológicos têm sido realizados em áreas de Matas Ciliares. O presente estudo foi realizado com o objetivo de caracterizar a composição florística e a estrutura fitossociológica de uma comunidade vegetal em área de mata ciliar, em processo de recuperação, na Fazenda Mãe Natureza em Santana do São Francisco - Sergipe. A vegetação objeto do estudo é resultado de um projeto-piloto que utilizou o plantio heterogêneo de espécies arbóreas nativas, que visou obter dados para subsidiar futuros modelos de restauração de áreas de mata ciliar degradadas na região do Baixo Rio São Francisco. Para tanto, realizou-se análise do solo da área para comparação com os dados do solo realizados na época da implantação do projeto inicial, levantamento florístico e fitossociológico, com a análise da estrutura horizontal e vertical, índice de diversidade de Shannon-Weaver (H’), índice de equabilidade de Peilou (J’), cobertura de copa (CC), similaridade florística e síndrome de dispersão e grupos sucessionais. Para o estudo fitossociológico do estrato arbustivo-arbóreo foi realizado o censo dos indivíduos presentes numa área de 1,66 ha, onde foram amostrados todos os indivíduos vivos com circunferência do caule ao nível de 1,30 cm (CAP) ≥ 6 cm. O levantamento florístico da área para todos os hábitos apresentou riqueza total de 165 espécies, 133 gêneros e 51 famílias, havendo predominância das espécies herbáceas, representadas por 44,8% das espécies identificadas. As famílias herbáceas que apresentaram maior riqueza de espécies foram Malvaceae (16,7%), Cyperaceae (13,7%), Asteraceae (11%), Fabaceae (8,2%) Poaceae (6,8%), que juntas representam 56,4% da riqueza em espécies herbáceas registradas na área. Através do levantamento da regeneração natural das espécies arbustivo-arbóreas da área, foram identificados indivíduos pertencentes a 70 espécies (arbustos 38,6% e 61,4% árvores), 58 gêneros e 25 famílias. Destas 70 espécies amostradas, 57 espécies não foram oriundas do plantio sendo, portanto, provenientes da regeneração natural via dispersão. Para o levantamento estrutural da área, foi mensurado um total 1.640 indivíduos, pertencentes a 52 espécies, 44 gêneros e 20 famílias. A densidade absoluta, estimada foi de 1.025 indivíduos ha-1 com área basal de 9,79 m2/ ha, diâmetro médio individual de 6,53 cm e altura média de 5,65 m. As famílias que mais contribuíram para essa riqueza florística foram Fabaceae, com 17 espécies, Anacardiaceae com cinco espécies, Rubiaceae com quatro espécies, Euphorbiaceae e Myrtaceae com três cada, Capparaceae, Meliaceae, Polygonaceae, Salicaceae e Sapindaceae com duas espécies cada, as demais famílias apresentaram apenas uma espécie cada. A espécie Mimosa caesalpiniifolia Benth., com 2,70 m2 de área basal foi a que apresentou os maiores valores em todos os parâmetros fitossociológicos analisados, fato este que pode indicar uma maior adaptação da espécie ao ambiente ou dominância ecológica desta espécie. O índice de diversidade de Shannon-Wiener (H’) para a amostragem com 1640 indivíduos foi de 2,78 nats/ind., o índice de Equabilidade de Pielou (J’) de 0,70, o Coeficiente de Mistura de Jentsch foi de 0,032 e o índice de dominância de Simpson encontrado foi 0,135. A área apresenta uma alta diversidade de espécies e alta dominância. As espécies da área em estudo foram agrupadas em três categorias de dispersão (zoocóricas, anemocóricas e autocóricas) e duas categorias de sucessão (pioneiras e clímax). A partir dessas classificações obteve-se 31 (59,62%) espécies classificadas como zoocóricas, sendo 18 pioneiras e 13 clímax, 15 (28,85%) espécies autocóricas, sendo 12 pioneiras e 3 clímax, e seis (11,54%) espécies anemocóricas, sendo quatro pioneiras e duas clímax. Independente da fisionomia analisada e comparada, observou-se uma baixa similaridade florística com outras áreas da região. Assim, todas as áreas analisadas apresentam particularidades florísticas definidas. Observa-se também que, ao longo dos anos, o solo está recompondo sua fertilidade, provavelmente devido à maior ciclagem de nutrientes e também pela cobertura da vegetação que promove uma maior proteção do solo, facilitando assim o estabelecimento de novas espécies na área. / São Cristóvão, SE
79

Dinâmica molecular e particionamento do marcador de spin di-terc-butil nitróxido em membranas de estrato córneo. Efeito de Terpenos / Molecular dynamics and partitioning Bookmark spin di-tert-butyl nitroxide in membrane of stratum corneum. Effect of Terpenes

CAMARGOS, Heverton Silva de 31 March 2009 (has links)
Made available in DSpace on 2014-07-29T15:07:11Z (GMT). No. of bitstreams: 1 dissertacao Heverton.pdf: 3726246 bytes, checksum: d1604716538cf27f6497805271c49501 (MD5) Previous issue date: 2009-03-31 / Terpenes are a very promising class of skin penetration enhancers especially due to their low potential of irritation in the skin. In this work, we have used the electron paramagnetic resonance (EPR) spectroscopy of the small spin label di-tert-butyl nitroxide (DTBN), which partitions the aqueous and hydrocarbon phases, to study the interaction of the terpenes ®-terpineol, 1,8-cineole, L(-)-carvone and (+)-limonene with the uppermost skin layer, the stratum corneum, and the membrane models of 1,2-dipalmitoyl-sn-glycero- 3-phosphatidylcholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). The EPR spectra indicated that the terpenes increase both the partition coe±cient and the rotational di®usion rate of the spin labels in the stratum corneum membranes whereas for DMPC and DPPC bilayers were observed similar e®ects only at temperatures below the liquid-crystalline phase. The EPR parameter associated to probe polarity inside the membranes showed thermotropic induced changes, suggesting relocations of spin probe, which were dependent of the membrane phases. While DMPC and DPPC bilayers showed abrupt changes in the partitioning and rotational correlation time parameters at the phase transitions, the SC membranes were characterized by slights changes in whole interval of measured temperatures, presenting the greatest changes or membranes reorganizations in the temperature range of v50 to v74±C. The results suggest that the terpenes act as spacers that weaken the hydrogen-bonded network at the polar interface thus °uidizing the stratum corneum lipids and, in consequence, increase the permeation of small polar molecules across the membranes. 2 / Os terpenos são uma classe muito promissora de facilitadores de permeação da pele devido aos seus baixos potenciais de irritação na pele. Neste trabalho utilizamos a espectroscopia de ressonância paramagnética eletrônica (RPE) do pequeno marcador de spin di-terc-butil nitróxido (DTBN) que particiona na fase aquosa e hidrocarbônica, para estudar a interação dos terpenos ®-terpineol, 1,8-cineol, L(-)-carvona e (+)-limoneno com a camada superior da pele, o estrato córneo, e membranas modelos de 1,2-dimiristoil-sn- glicero-3-fosfocolina (DMPC) e 1,2-dipalmitoil-sn-glicero-3-fosfocolina (DPPC). Os espectros de RPE indicaram que os terpenos aumentam o coeficiente de partição e a taxa de difusão rotacional do marcador de spin nas membranas de estrato córneo, enquanto que para as bicamadas de DMPC e DPPC o efeito foi semelhante somente nas temperaturas abaixo da fase líquido-cristalina. O parâmetro de EPR associado µa polaridade do marcador de spin no interior das membranas mostrou mudanças induzidas termotropicamente, sugerindo que a posição média da molécula marcada muda com a temperatura e fases das membranas. Enquanto as bicamadas de DMPC e DPPC mostraram abruptas mudanças nos parâmetros da partição e do tempo de correlação rotacional com as transições de fase, as membranas de EC forão caracterizadas por suaves mudanças em todo o intervalo de temperatura medido, apresentando as maiores mudanças ou reorganizações das membranas na faixa de temperatura de ~50 a ~74°C. Os resultados sugerem que a terpenos atuando como espaçadores dos lipídios que compõem as membranas, enfraquecem as redes de ligações de hidrogênio na interface polar, e isto leva a um aumento da °uidez dos lipídios do estrato córneo e, em consequência, a uma maior permeação de moléculas polares através das membranas.
80

Encapsulação da vitamina c em lipossomas para o tratamento do envelhecimento cutâneo: desenvolvimento tecnológico, analítico e avaliação da performance biológica in vitro em modelos de permeação cutânea e em linhagens celulares de queratinócitos e fibroblastos

Maione-Silva, Lorena 29 February 2016 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-10-18T13:45:31Z No. of bitstreams: 2 Tese - Lorena Maione Silva - 2016.pdf: 2670473 bytes, checksum: 1799734a5c9cb4a8d11804bbf32a24a5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2016-10-18T16:43:26Z (GMT) No. of bitstreams: 2 Tese - Lorena Maione Silva - 2016.pdf: 2670473 bytes, checksum: 1799734a5c9cb4a8d11804bbf32a24a5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-18T16:43:26Z (GMT). No. of bitstreams: 2 Tese - Lorena Maione Silva - 2016.pdf: 2670473 bytes, checksum: 1799734a5c9cb4a8d11804bbf32a24a5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Skin aging involves events that lead to the reduction of its structural integrity and loss of biological functions. The reactive oxygen species (ROS) are potentially able to generate damage of tissues and are related with the cutaneous photoaging. Antioxidant molecules like vitamin C (VC) are capable of fighting these ROS. Besides, VC acts in the synthesis of collagen in the skin, the primary protein responsible for supporting its connective tissues. However, beneficial skin effects are only obtained when the VC is applied topically. In this work, liposomes containing VC for topical administration were developed and characterized. For quantification of VC in different matrixes, including pharmaceutical products, cosmetics, and porcine ear skin, a quantitative analytical method was developed and validated by high performance liquid chromatography with diode array detection (HPLC-DAD) using ion-pair reversed phase. The developed analytical method was capable of quantifying VC without the interference of the various components of the pharmaceutical formulations and the endogenous compounds of the biological matrix. The diluent chosen to extract and dilute VC was a mixture of water and methanol (4:1, v/v) acidified to pH 3.0 with phosphoric acid, with additional 0.02% sodium thiosulfate. This diluent was the most efficient to stabilize VC compared with other pH conditions and compositions, maintaining the amount of VC close to 100% after 10 days at 4°C. In this way, a method for quantification of VC that could be widely used by pharmaceutical companies and research laboratories was developed. It was precise and accurate in the evaluation of the content of VC in biological matrixes and different pharmaceutical formulations, making it advantageous towards other methods. Liposomes with VC were prepared by dehydration-rehydration vesicles method (DRV). Liposomes containing phosphatidylcholine (PC) or a mixture of PC and cholesterol and other electrically charged lipids were prepared, and liposomes with positive, negative and neutral charges were obtained. All formulations presented mean size inferior to 200 nm and low polydispersity index (<0.2). Encapsulation efficiency of VC was directly influenced by the amount of liposomes that were formed. In skin permeation studies, the association of VC in the liposomes only allowed greater retention in the dermis when negatively charged liposomes were used. After 6 hours, the application of this formulation promoted high skin retention of VC, with an accumulation of 37.9 ± 12.02 μg/cm2 and 73.95± 23.23 μg/cm2 in the epidermis and dermis, respectively. Liposomes were capable of increasing the flow of VC through the skin. The presence of cholesterol and negative charge in the liposomes promoted an increase in VC flow of 4 and 7 times, respectively, when compared to free drug (FD). The interaction of liposomes with live biological membranes was simulated in keratinocytes (HaCat) and fibroblasts (3T3) through the analysis of cell internalization of liposomes. For this assay, during the preparation of liposomes, fluorescent lipids were used to label the lipid membrane (coumarin and rhodamine). After treatment, the groups treated with negatively charged liposomal formulation presented superior fluorescence than the groups treated with other formulations and control, suggesting a higher interaction between the negatively charged liposomes and keratinocytes and fibroblasts. Thus, this negatively charged formulation was compared with free VC in the cell regeneration of keratinocytes after exposure to UVA radiation and in the production of collagen type I in fibroblasts. In both cases, the beneficial effect was only observed when VC was encapsulated in the liposomes. Therefore, the technological development of a liposomal formulation containing VC generated a formulation with a stability of at least 30 days and with characteristics that favored its retention and skin flow. Besides, the encapsulation of VC in negatively charged liposomes promoted an enhancement in the efficacy of regeneration of keratinocytes and the synthesis of collagen in fibroblasts. / O envelhecimento da pele envolve eventos que levam à redução da integridade estrutural e perda das suas funções biológicas. As espécies reativas de oxigênio (EROs) são potencialmente capazes de gerar danos teciduais e estão relacionadas com o fotoenvelhecimento cutâneo. Moléculas antioxidantes como a vitamina C (VC) são capazes de combater estes compostos. Além disso, a VC atua na síntese de colágeno na pele, proteína fundamental à sua sustentação. No entanto, efeitos benéficos cutâneos só são obtidos quando a VC é aplicada topicamente. Neste trabalho, foram desenvolvidos e caracterizados lipossomas contendo VC para a aplicação tópica. Para a quantificação da VC em diferentes matrizes, incluindo produtos farmacêuticos, cosméticos e pele de orelha de porco, foi desenvolvido e validado um método quantitativo por cromatografia líquida de alta eficiência acoplada à detector de arranjo de diodos (HPLC-DAD) por pareamento iônico em fase reversa. O método analítico desenvolvido foi capaz de quantificar a VC sem sofrer interferência dos diversos componentes das formulações farmacêuticas e dos compostos endógenos da matriz biológica. O diluente escolhido para extrair e diluir a VC foi a mistura contendo água e metanol (4:1, v/v) acidificada com ácido fosfórico para pH 3,0 com a adição de 0,02% de tiossulfato de sódio. Este diluente foi o mais eficaz na estabilização da VC, comparando-se com outras condições de pH e composição, com a manutenção da quantidade de VC próximo a 100% depois de 10 dias a 4ºC. Desta forma, foi desenvolvido um método de quantificação da VC que pode ser amplamente utilizado por indústrias farmacêuticas e laboratórios de pesquisa, uma vez que foi preciso e exato na avaliação do teor da VC em matriz biológica e em diferentes preparações farmacêuticas. Os lipossomas contendo VC foram produzidos pela técnica de dehydrationrehydration vesicles (DRV). Foram produzidos lipossomas contendo fosfatidilcolina (PC) ou mistura de PC com colesterol e outros lipídeos eletricamente carregados, obtendo-se assim lipossomas com carga elétrica neutra, positiva ou negativa. Todas as formulações apresentaram tamanho médio inferior a 200 nm e baixo índice de polidispersão (< 0,2). A eficiência de encapsulação da VC foi diretamente influenciada pela quantidade de lipossomas formados. Nos estudos de permeação cutânea, a associação da VC aos lipossomas só permitiu maior retenção na derme quando foram utilizados os lipossomas carregados negativamente. Após 6 horas, a aplicação desta formulação proporcionou alta retenção cutânea da VC, com acúmulo de 37,19 ± 12,02 μg/cm2 e 73,95 ± 23,23 μg/cm2 na epiderme e derme, respectivamente. Os lipossomas foram capazes de aumentar o fluxo de VC através da pele. A presença de colesterol e carga superficial negativa nos lipossomas provocaram aumento do fluxo de VC de 4 e 7 vezes, respectivamente, em relação ao fármaco livre (FL). A interação dos lipossomas com membranas biológicas vivas foi simulada em linhagens de queratinócitos (HaCat) e fibroblastos (3T3) através da análise da internalização celular dos lipossomas. Neste caso, durante o preparo dos lipossomas foram adicionados marcadores de membrana lipídica fluorescentes (rodamina e cumarina). Após tratamento, os grupos que receberam formulação lipossomal com carga superficial negativa apresentaram fluorescência superior aos grupos tratados com as outras formulações e o controle, sugerindo maior interação entre os lipossomas negativos e os queratinócitos e fibroblastos. Assim, a formulação com carga negativa foi comparada com a VC livre na regeneração celular de queratinócitos após exposição à radiação UVA e na produção de colágeno tipo I em fibroblastos. Nos dois casos, os efeitos benéficos só foram observados com a encapsulação da VC nos lipossomas. Desta forma, o desenvolvimento tecnológico de uma formulação lipossomal contendo VC, permitiu a obtenção de uma formulação com estabilidade de pelo menos 30 dias e com características que favoreceram sua retenção e fluxo cutâneo. Além disso, a encapsulação da VC em lipossomas negativos proporcionou aumento da sua eficácia na regeneração de queratinócitos e na síntese de colágeno em fibroblastos.

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