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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.
481

Estudo e desenvolvimento de lipossomas com potencial para aplicação em base cosmética / Study and development of liposomes with potencial cosmetic application

Laura Farkuh 04 February 2016 (has links)
A acne vulgar é uma das doenças cutâneas mais comuns, apresentando como um de seus fatores fisiopatológicos primários a colonização pelo microrganismo Propionibacterium acnes. Atualmente, têm-se buscado terapias alternativas para o combate ao P. acnes, destacando-se alguns ácidos graxos, como o ácido laúrico (LA). O LA é uma molécula pouco solúvel em água, sendo possível sua incorporação em lipossomas. Os lipossomas apresentam capacidade de encapsulação/ liberação de ativos e impedem a desidratação da pele, tornando-se ingredientes inovadores na área de cosméticos. Foram preparados lipossomas de dipalmitoilfosfatidilcolina (DPPC) contendo diferentes concentrações de LA, que variaram de 0 a 50% da concentração total em mol, em quatro pHs: 9,0, 7,4, 5,0 e 3,0. Nestes pHs o estado de protonação do LA muda variando de 0 a -1. Os lipossomas foram extrusados por filtros com poros de 100 nm de diâmetro visando à obtenção de vesículas unilamelares grandes (LUV). As LUV foram caracterizadas quanto a sua estabilidade em condições de prateleira, temperatura de transição de fase da bicamada, encapsulamento no interior aquoso, liberação do LA, difusão das vesículas na pele e seus aspectos morfológicos foram caracterizados por espalhamento de raios-X a baixo ângulo (SAXS) e crio-microscopia eletrônica de transmissão. Estudos de estabilidade mostraram que independentemente da concentração de LA, as formulações são mais estáveis em pHs mais altos, quando LA está em sua maioria na forma de laurato. Os experimentos de DSC revelaram que em pHs 3,0 e 5,0 e concentrações maiores de LA, a interação deste ácido graxo com as bicamadas é favorecida, havendo um aumento da temperatura de transição de fase (Tm) e diminuição da cooperatividade. Análises de taxa de incorporação de sondas hidrofílicas confirmaram a presença de um compartimento aquoso interno para as vesículas de DPPC:LA. O LA conseguiu permear a pele no período avaliado e pouco LA foi liberado das vesículas em condições de temperatura ambiente. A morfologia das LUV se mostrou bem diferente da esperada e se observaram vesículas com mais de uma bicamada e outros formatos que não o esférico. Estes resultados podem auxiliar na otimização das condições para uma formulação que poderá ser usada no tratamento da acne, aumentando a eficácia do LA no sítio alvo. / Acne vulgaris is one of the most common skin diseases, presenting as one of its causes the microorganism Propionibacterium acnes colonization. Currently, it has been sought alternatives therapies against P. acnes, especially some fatty acids, like the lauric acid (LA). LA is a molecule with low water solubility, allowing its incorporation in liposomes. Liposomes have encapsulation/release capacity of drugs and promote skin lipids regeneration, becoming an innovative ingredient in cosmetics area. Dipalmitoylphosphatidylcholine (DPPC) vesicles containing different LA concentrations were prepared at pHs: 9.0, 7.4, 5.0 and 3.0. At these pHs the LA protonation changes and its charge varies from 0 to -1. The vesicles were extruded through filters containing pores of 100 nm to obtain large unilamellar vesicles (LUV) that were characterized for stability in shelf conditions, bilayer phase transition temperature, aqueous internal compartment encapsulation, LA release and in vitro skin permeation. Its morphological features were characterized by small angle X-ray scattering (SAXS) and cryo-electron transmission microscopy. Stability assays showed that, regardless LA concentration, formulations were more long-term stable in higher pHs, when LA is mostly in the form of laurate. The differential scanning calorimetry, DSC, experiments showed that, at pHs 3.0 and 5.0 and higher LA concentrations, the interaction between the bilayer and LA is favored, increasing phase transition temperature (Tm) and reducing cooperativity. Incorporation of hydrophilic probes confirmed the presence of an internal aqueous compartment in DPPC:LA vesicles. The LA managed to permeate the skin on the period evaluated and, in ambient conditions, low LA concentration was released from the vesicles. LUV containing more than one bilayer and non-spherical structures were observed. The obtained results may help in the optimization of the conditions for a formulation that can be used in the treatment of acne and improving the effectiveness of LA delivery to the target site.
482

Digestibilidade e propriedades nutricionais do feijão (Phaseolus vulgaris, L.) e de suas proteínas isoladas / Digestibility and nutritional properties of Phaseolus vulgaris, L and itheir major protein fractions

Ursula Maria Lanfer Marquez 19 May 1988 (has links)
O estudo da digestibilidade e do aproveitamento biológico do feijão (Phaseolus vulgaris, L. ),variedade Carioca e de suas principais frações protéicas foi realizado em ensaios biológicos com ratos, após tratamento térmico adequado (cocção). À metodologia convencional, baseada no \"Ganho de Peso\" e na razão entre o N ingerido e excretado, seguiu-se uma técnica utilizando feijões e suas frações protéicas previamente marcadas com 15N e 35S. A ingestão das rações causou respostas diferentes nos animais, específicos para cada fonte protéica. Os animais alimentados com o feijão integral tiveram reduzido aproveitamento biológico e excretaram 34% do nitrogênio ingerido, sendo este valor 3-4 vezes superior ao causado pela ingestão da ração controle de caseína. As frações, albumínicas e glutelínicas, apresentaram valores de \"NPR\" e \"Ganhos de Peso\" superiores, apesar de sua relativa baixa digestibilidade (70-80%). A globulina G1, altamente digerível (92%) teve uma utilização biológica muito reduzida, não permitindo o crescimento dos animais. O ensaio biológico do feijão e de suas proteínas, marcados isotopicamente, permitiu diferenciar a origem do nitrogênio e do enxofre fecal, se endógena ou exógena. A concentração de 15N em excesso, determinado nas fazes 12 horas após o início da ingestão das rações marcadas, consideramos ser de origem exógena, sendo esses valores interpretados comparativamente. A ingestão de feijões cozidos causou nos animais uma excreção de nitrogênio proveniente do próprio feijão, 10 vezes superior à elevada perda de nitrogênio endógeno, totalizando o equivalente a 34% do nitrogênio ingerido. Ratos alimentados com a globulina G1 excretaram nas primeiras 12 horas apenas quantidades muito reduzidas de 15N, e mesmo na fase de equilíbrio (4º - 6º dia de ingestão da reação marcada ) quando o 15N excretado corresponde ao exógeno + endógeno já marcado, a perda de N total não ultrapassou 10% do ingerido. A ingestão da fração albumínica, por sua vez, causou uma eliminação de 20% do N total ingerido, com participação tanto do N exógeno como endógeno. A interpretação dos resultados baseados na eliminação do enxofre e de seu radioisótopo 35S, mostrou um perfil de excreção semelhante ao observado para o 15N, embora em níveis levemente superiores. / Studies with growing rats were carried out to determine the digestibility, and nutritive value of beans (Phaseolus vulgaris, L.) Carioca variety, and their major protein fractions, after proper heat treatment in order to inactivate the antiphysiological factors. The conventional method based on weight gain and the relation between the ingested and excreted nitrogen was followed by a balance technique, employing either whole beans or their protein fractions, previously labeled with 15N and 35S. The ingestion of the diets showed different nutritive responses, which were specific for each of the diets. Low biological value and digestibility were observed by rats fed on whole bean-containing diets, and as a consequence an excretion of 34% the ingested nitrogen was noted. This value was 3-4 times higher than the one excreted by the casein-control animals. Higher vakues of \"weight gain\" and NPR were obtained with the albumin and glutelin based diets, although their digestibilities were relatively low (70 - 80%). The globulin G1 was highly digestible (92%) nevertheless it appeared to have very low nutritional values and did not allow the growth of rats. The biological assay with isotopically labeled beans and proteins, allowed to differenciate the origin of fecal nitrogen and sulfur, as exogenous or endogenous. The concentration of 15 N in excess, which appeared in the feces 12 hours after the first ingestion of the labeled diets, was considered to be of exogenous origin; these values can be interpreted comparatively. The ingestion of the cooked whole beans promoted an excretion of exogenous nitrogen, 10 times higher than that excreted by the rats on the globulin G1 diet, which with the high excretion of endogenous nitrogen, totalized 34% of the ingested one. Rats fed on the globulin G1 excreted, in the first 12 hours, only small amounts of 15N, even in the steady - state (4º - 6ºth day on feeding the labeled diet), when the excreted 15N corresponded to both, exogenous and labeled endogenous excretion reached, the maximum loss (about 10% of the ingested total nitrogen). The feeding of albumin based diets stimulated an excretion of 20% of the ingested nitrogen, due to exogenous and endogenous origin. The interpretation of the results based on the balance of total sulfur and their radioactive isotope (35S) showed an excretion pattern, similar to that of the 15N, although in absolute values (of excretion) it was a little higher than that representing the nitrogen loss.
483

Movimientos paraheliotrópicos en plantas de porotos (Phaseolus vulgaris L. cv. Orfeo INIA) y su efecto como mecanismo de fotoprotección / Paraheliotropic movements in bean plants (Phaseolus vulgaris l. cv. Orfeo INIA) and their effect as a photoprotection mechanism

Zamorano Venegas, Silvia Camila January 2012 (has links)
Memoria para optar al título profesional de Ingeniero Agrónomo Mención Fitotecnia / Se procedió a medir la capacidad fotosintética y la eficiencia del uso del agua instantánea en foliolos de poroto obligados a la horizontalidad y foliolos de libre movimiento. Para ello, se trabajó con plantas del cv. Orfeo INIA establecidas en campo, con el objetivo de determinar la necesidad de las plantas de contar con movimientos paraheliotrópicos como mecanismo de fotoprotección y su efecto en la disminución de la capacidad de asimilación de CO2, bajo condiciones de riego. La fijación foliar se llevó a cabo 60 días después de siembra, mediante alambre y pinzas, obligando a la constante horizontalidad del foliolo central de la hoja ubicada en el tercer nudo reproductivo (T1), mientras que en plantas independientes de procedió a marcar los foliolos con libre movimiento ubicados en la misma posición (T2). Las mediciones, que se realizaron los días 2, 5, 10, 17 y 22 después de la fijación foliar, a las 12:00 h, correspondieron a la temperatura foliar, radiación incidente, humedad y temperatura del aire, asimilación de CO2, conductancia estomática, concentración interna de CO2, tasa transpiratoria, contenido de clorofila y eficiencia del uso del agua instantánea.
484

Produção sustentável do feijão comum : inoculação, coinoculação e adubação mineral em cultivares de ciclo precoce /

Bettiol, João Víctor Trombeta. January 2019 (has links)
Orientador: Leandro Borges Lemos / Resumo: A utilização de manejos sustentáveis para maximizar a produtividade das culturas sem aumentar os custos de produção é um dos grandes desafios da agricultura atual. Assim, objetivou-se avaliar o efeito de manejos de fornecimento de nitrogênio, associando formas de inoculação com Rhizobium tropici, co-inoculação com Azospirillum brasilense e adubação mineral de cobertura, no desempenho agronômico de cultivares de feijão comum do grupo comercial carioca de ciclo precoce. O experimento foi instalado em delineamento em blocos casualizados (DBC), no esquema fatorial 2x12 (2 cultivares e 12 manejos de fornecimento de N), com quatro repetições. Para os manejos de fornecimento de N foram associados adubação mineral de cobertura com N (45 e 90 kg ha-1 de N), inoculação de sementes com Rhizobium tropici e coinoculação via semente e foliar com Azospirillum brasilense. Foram avaliados o número de trifólios por planta, área foliar, índice de clorofila, teor de nitrogênio foliar e nos grãos, massa seca de plantas, número de vagens por planta, número de grãos por planta e produtividade, número de nódulos por planta, massa seca de nódulos por planta, massa seca de raízes e eficiência de nodulação. Os dados foram submetidos à análise de variância (teste F) e, quando necessário, as médias foram agrupadas pelo teste de Scott-Knott a 5% de probabilidade. Com exceção da massa seca de plantas, todas as variáveis analisadas apresentaram máxima resposta no tratamento com inoculação de sementes com Rh... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of sustainable managements techniques to maximize crop productivity without increasing production costs is one of the great challenges of modern agriculture. The objective of this study was to assess the effect of different nitrogen management by testing the inoculation with Rhizobium tropici, co-inoculation with Azospirillum brasilense, and topdressing N fertilization on the agronomic performance of common bean cultivars of early cycle. The experiment was carried out in a randomized block design (RBD), in a 2x12 factorial scheme (2 cultivars and 12 N supply management), with four replications. For N supply management, it was used topdressing N fertilization (45 and 90 kg ha-1 N), seed inoculation with Rhizobium tropici, and seed and leaf co-inoculation with Azospirillum brasilense. It was evaluated: the number of trifolium per plant, leaf area, chlorophyll index, leaf and grain nitrogen content, dry mass of plants, number of pods per plant, number of grains per plant and yield, number of nodules per plant, dry matter of nodules per plant, dry matter of root, and nodulation efficiency. Data were subjected to analysis of variance (F test) and, when necessary, means were grouped by Scott-Knott test at 5% probability. Except for the dry mass of plants, all variables analyzed showed maximum response in the treatment with seed inoculation with Rhizobium tropici, foliar application of Azospirillum brasilense, and topdressing fertilization with 90 kg ha-1 of N. In general, t... (Complete abstract click electronic access below) / Mestre
485

Treatment of Acne Vulgaris by Biofeedback-Assisted Cue-Controlled Relaxation and Guided Cognitive Imagery

Brown, Barry W. 05 1900 (has links)
The primary purpose of the present study is to demonstrate that acne vulgaris can be reduced by psychological treatment. A cognitive-behavioral adjunctive intervention involving biofeedback-assisted relaxation and cognitive imagery procedures for the treatment of acne vulgaris was investigated in this study with 30 patients, already receiving traditional dermatological treatment, as participants. A three-group design was used which consisted of a treatment (relaxation-imagery), a rational behavior group therapy attention-comparison, and a medical intervention control (medication and lesion extraction) group.
486

Photobioreactor Design for Improved Energy Efficiency of Microalgae Production

Burns, Alexander 01 December 2014 (has links)
ABSTRACT Photobioreactor Design for Improved Energy Efficiency of Microalgae Production Alexander Burns The objective of this research was to investigate a new photobioreactor (PBR) design for microalgae production that retains the typical advantages of existing tubular PBRs while reducing power consumption by providing simultaneous culture circulation and gas exchange with airlift alone and no centrifugal recirculating pump. Traditional tubular PBR designs feature a compressed air supply and a centrifugal pump for culture circulation and gas exchange. Circulation and gas exchange in a closed-system PBR is necessary to keep the algae suspended and to provide sufficient mass transfer (mainly for the exchange of oxygen and carbon dioxide). In a traditional tubular PBR sparged air keeps the culture well mixed and strips out excess dissolved oxygen in an airlift-column unit, while the centrifugal pump circulates the culture in the tubular stage and decreases the amount of air bubbles traveling into this stage; where most of the photosynthesis occurs. The PBR design proposed herein does away with the usual centrifugal pump. The air blower performs both gas exchange in the airlift columns and system-wide circulation. This builds on a previous tubular PBR design that provides circulation and gas exchange by airlift alone, which was patented by Cathcart in 2011. However, the Cathcart patent does not provide data on mixing, gas exchange, energy consumption, flow regime or biomass productivity. The new design described here builds on the Cathcart design, but includes several unique design features, such as larger diffuser columns which provide airlift-induced flow for a series of vertical PBR tubes. To perform a power consumption v analysis, a pilot-scale prototype of the new PBR design was built and operated. The prototype PBR consisted of two airlift columns attached to 9 m of vertical serpentine tubing connected to the top and bottom by standard 90-degree PVC elbows in a U-bend fashion to each column to make a total working volume of 235 L. The airlift columns were about 1.5 m tall and 30.5 cm ID, while the serpentine tubes were about 0.9 m tall and 7.6 cm ID to make a total of five vertical tubes for every airlift column. Data collected for this prototype design suggest an average overall areal productivity (OAP) of 111 g m-2 d-1 (g biomass m-2 total land area with empty space day-1), an average illuminated surface productivity (ISP) of 14.3 g m-2 d-1 (g biomass m-2 reactor photo-stage day-1), an average volumetric productivity (VP) of 0.55 g L-1 d-1 (g biomass L-1 reactor working volume day-1), a specific power input in the range of 330 to 360 W m-3 (W power needed for culture circulation and gas exchange m-3 reactor working volume) and a specific biomass productivity (SBP) in the range of 17.6 to 19.1 mg kJ-1 (mg biomass kJ-1 energy needed for culture circulation and gas exchange) with Chlorella vulgaris as the model algae. The biomass productivity per energy input (SBP) of the new PBR design appears to be higher than that of similar designs currently described in the literature. Elimination of the centrifugal pump in a tubular PBR design is a concept worth further study for potential energy savings.
487

Occurence and transmission of Toxoplasma gondii in European starlings (Sturnus vulgaris) of northern California

Haslett, Theresa Marie 01 January 1977 (has links)
This research was performed to determine; (1) the prevalence of Toxoplasma antibodies among starlings in Northern California, (2) if such starlings can transmit the disease, and (3) if tissues from seropositive starlings contain encysted forms of T. gondii.
488

Efeitos de nanopartículas de prata biossintetizadas por Aspergillus niger em diferentes níveis tróficos /

Ribeiro, Bruna Marques. January 2020 (has links)
Orientador: Cristiane Angélica Ottoni / Resumo: A utilização de nanopartículas de prata (AgNP) biológicas nos dias atuais é uma alternativa promissora frente as obtidas por via sintética (VS), uma vez que, não geram resíduos em seu processo de síntese e possuem superfície revestida por proteínas que viabilizam sua incorporação em diversos compostos comerciais, sendo os fármacos os de maior destaque. O efeito do descarte de AgNP sintéticas no meio ambiente é atualmente fonte de investigação de diversos grupos de pesquisa, entretanto, são restritas as informações associadas as AgNP biológicas. Diante deste contexto, o presente estudo utilizou a AgNP IBCLP20 biossintetizada pelo fungo Aspergillus niger para avaliar a sua ação antimicrobiana e efeito tóxico em ambiente aquático dulcícula utilizando organismos pertencentes a diferentes níveis tróficos. Nos ensaios antimicrobianos a AgNP IBCLP20 apresentou excelente ação antibacteriana em uma faixa de concentração de 5 a 100 µg/mL e ação antifúngica na faixa de concentração de 20 a 100 µg/mL. A densidade celular da microalga Chrorella vulgaris, quando exposta a AgNP IBCLP20 e ao sal precursor AgNO3, na maior concentração analisada (100 uM/mL) e após 96 horas de incubação, apresentou uma taxa de redução de 34,4% e 85,71%, respectivamente. Nas mesmas condições supracitadas, só foi detectada viabilidade celular da microalga quando exposta a AgNP biológica (65,38%). A letalidade média em D. silimis causada pelas AgNP IBCLP20 foi estimada a uma concentração de 4,06 μg/L (2,29 -6,42).... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of biological silver nanoparticles (AgNP) today is a promising alternative compared to those obtained synthetically (VS), since they do not generate residues in their synthesis process and have a surface coated with proteins that enable their incorporation in several commercial compounds, with drugs being the most prominent. The effect of discarding synthetic AgNP in the environment is currently a source of investigation for several research groups, however, information associated with biological AgNP is restricted. In this context, the present study used the AgNP IBCLP20 biosynthesized by the fungus Aspergillus niger to evaluate its antimicrobial action and toxic effect in aquatic dulcicle environment using organisms belonging to different trophic levels. In antimicrobial tests, AgNP IBCLP20 showed excellent antibacterial action in a concentration range of 5 to 100 µg / mL and antifungal action in the concentration range of 20 to 100 µg / mL. The cell density of the microalgae Chrorella vulgaris, when exposed to AgNP IBCLP20 and the precursor salt AgNO3, in the highest concentration analyzed (100 uM / mL) and after 96 hours of incubation, showed a reduction rate of 34.4% and 85.71 %, respectively. Under the same conditions mentioned above, cell viability of the microalgae was only detected when exposed to biological AgNP (65.38%). The average lethality in D. silimis caused by AgNP IBCLP20 was estimated at a concentration of 4.06μg/L (2.29 -6.42). , The physiological ... (Complete abstract click electronic access below) / Mestre
489

Isolation and characterization of bacterial endophytes for growth promotion of Phaseolus vulgaris under salinity stress

Thompson, Biosha January 2020 (has links)
>Magister Scientiae - MSc / As the global human population grows, so does the demand for faster food production rates. Owing to this, agricultural practices have had to expand and move into semi-arid and arid regions, too, where frequent irrigation is essential. However, irrigated ground water contains many salt ions (mainly Na+ and Cl-) which contribute to soil salinization on croplands. Soil salinity negatively impacts crop growth and yield and thus, strategies for the alleviation of salt stress on crop plants have had to be developed. This study assessed the use of plant growth promoting bacteria (PGPB). The aim of this study was to isolate, identify and characterize bacterial endophytes isolated from the halophyte, Arctotheca calendula. Endophytes were identified using 16S rDNA and were screened for plant growth promoting properties including nitrogen fixation, phosphate and zinc solubilization, siderophore, ammonia and indole-3-acetic acid (IAA) when exposed to 0 mM, 300 mM and 600 mM NaCl. The endophytes had been identified as Erwinia persicina NBRC 102418T, Bacillus marisflavi JCM 11544T, Ochrobactrum rhizosphaerae PR17T, Microbacterium gubbeenense DSM 15944T and Bacillus zhangzhouensis DW5-4T and all of which had demonstrated some plant growth promoting characteristics. Thereafter, we aimed to demonstrate plant growth promotion of P. vulgaris cv. Star 2000 inoculated with PGPB under salinity stress. P. vulgaris cv. Star 2000 seeds were inoculated with the PGPB and exposed to 0 mM and 100 mM NaCl. Post-harvest, plants were assessed for their dry mass, cell death, superoxide concentration and nutrient content. It was discovered that salinity negatively impacted P. vulgaris cv. Star 2000’s dry mass, NaCl-induced cell death, and differentially influenced superoxide concentration, nutrient uptake and content of the leaf and root material in the inoculated and control treatments. However, the isolated PGPB had been able to mitigate the negative effects of soil salinity on P. vulgaris cv. Star 2000.
490

The cause and treatment of acne vulgaris: fact versus fiction

Wan, Steven Guo 03 November 2015 (has links)
Acne vulgaris is a complicated disease. It is primarily caused by dead skin, excessive sebum, and bacteria proliferation, all of which clogs hair follicles. The nature of this disease can start as comedone acne that affects young children, which progress into inflammatory acne in adolescent. The disease can persist into adulthood and is even reported to affect those 40 years of age. In adulthood, acne is more prevalent in women than in men. In addition to scarring and other physical damage, acne can also be psychologically damaging, especially in adolescents and adults. This paper will attempt to elucidate the causes of acne which includes: hormone, diet, smoking, environment, and human biology. Then this paper will explain common treatments that include: oral antibiotics, isotretinoin, topical treatment, hormone therapy, and light and laser therapy. After establishing researched causes and treatments, this paper will look into misconceptions regarding acne. Since there are many myths surrounding acne, this paper will only visit a few well documented misconceptions. Finally, this paper will formulate some new areas of research that acne literature is lacking. Acne is a serious disease and new information and research must be done in order to clear up misconceptions and allow physicians to provide better treatment.

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