Dissertations / Theses on the topic 'Dc extraction'

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
During its evolutionary process, plants have developed biosynthetic pathways by which they produce and accumulate a wide variety of secondary compounds that receive this name because they are not directly involved in the primary processes of plant growth and development. Many of these secondary compounds are responsible for chemical protection of plants against pathogens, herbivores, competing plants, ultraviolet radiation and other environmental stresses. The production of secondary metabolites can vary quantitatively and qualitatively between individuals of the same species, between plants of different species, between organs, between stages of plant development and are under influences of environmental factors. Studies of the biological effects of these compounds represent an important tool for the development of more specific and natural pesticides that are less harmful to the environment, as well as drugs and natural preservatives for food. Myrcia splendens (Sw.) DC. is a tree species found in the Brazilian cerrado and there are few published papers dealing with this species and its secondary metabolites to act as potential natural pesticides, antioxidant and antifungal. The methodology for the extraction of secondary metabolites can determine the composition of extracts and influence the activity of them. In this sense, in the first chapter of this work investigations were carried out on the phytotoxic potential of extracts of M. splendens young leaves from two different extraction methodologies. The 2C extract had the highest overall phytotoxic activity, showing promise in the search phytotoxic substances. In the second chapter, we investigate the phytotoxic potential of extracts and fractions of mature leaves of M. splendens from the two extraction methods carried out and was identified one of the secondary metabolites possibly associated with the phytotoxicity of the most active fractions. 2B fraction had the highest total inhibitory activity and so was fractionated, resulting in 14 fractions, which were also tested in wheat coleoptile. The FM8 and FM9 fractions, which had inhibitory activity and sufficient income, were subjected to HPLC for isolation of major compound. Identification by NMR spectra revealed that the major compound is miricitrin (myricetin-3-O-rhamnoside). In the last chapter, the extracts of mature leaves of M. splendens were tested for their antioxidant potential based on their ability to react with the free radical DPPH (2,2-diphenyl-1-picrylhidrazila) and antifungal potential using the plant pathogenic fungus Alternaria alternata as the target species. Most of the extracts showed a strong antioxidant activity, especially those iv! ! extracted with more polar solvents. On the other hand, only one of the extracts (2B) showed inhibitory activity on mycelial growth of the phytopathogenic fungus tested.
Ao longo do seu processo evolutivo, as plantas desenvolveram rotas biossintéticas pelas quais produzem e acumulam uma imensa variedade de compostos secundários, que recebem este nome por não estarem diretamente envolvidos nos processos primários de crescimento e desenvolvimento vegetal. Muitos desses compostos secundários são responsáveis pela defesa química das plantas contra patógenos, herbívoros, plantas competidoras, radiação ultravioleta e outros estresses ambientais. A produção de metabólitos secundários pode variar quantitativa e qualitativamente entre indivíduos de uma mesma espécie, entre plantas de espécies diferentes, entre órgãos, entre estágios do desenvolvimento vegetal e sobre influências de fatores ambientais. Os estudos realizados sobre os efeitos biológicos destes compostos representam uma importante ferramenta para o desenvolvimento de agroquímicos naturais mais específicos e menos prejudiciais ao ambiente, bem como de medicamentos e conservantes naturais para a indústria alimentícia. Myrcia splendens (Sw.) DC. é uma especie arbórea encontrada no cerrado brasileiro e existem poucos os trabalhos publicados que tratam de investigações do potencial desta espécie e de seus metabólitos secundários para atuarem como pesticidas naturais, antioxidantes e antifúngicos. A metodologia empregada para a extração de metabólitos secundários pode determinar a constituição e rendimento dos extratos e influenciar a atividade dos mesmos. Nesse sentido, no primeiro capítulo deste trabalho foram realizadas investigações sobre o potencial fitotóxico de extratos de folhas jovens de M. splendens oriundos de duas metodologias de extração diferentes. O extrato 2C teve a maior atividade fitotóxica geral, se mostrando promissor na busca de substâncias fitotóxicas. No segundo capítulo, foi investigado o potencial fitotóxico de extratos e frações de folhas maduras de M. splendens das duas metodologias de extração realizadas e foi identificado um dos metabólitos secundários possivelmente associado à fitotoxicidade das frações mais ativas. A fração 2B apresentou a maior atividade inibitória total e por isso foi fracionada, resultando em 14 frações, que também foram testadas em coleóptilos de trigo. As frações FM8 e FM9, que possuíam atividade inibitória e rendimento suficiente, foram submetidas a CLAE para isolamento do composto majoritário. A identificação foi feita por espectros de RMN e revelou que o composto majoritário é a miricitrina (miricetina-3-O-ramnosídeo). No último capítulo, os extratos de folhas maduras de M. splendens foram testadas quanto ao seu potencial antioxidante baseado habilidade de reagir com o radical livre DPPH (2,2-difenil-1-picrilhidrazila) e antifúngico usando como espécie-alvo o fungo fitopatogênico Alternaria ii! ! alternata. A maior parte dos extratos apresentaram atividade antioxidante muito forte, especialmente aqueles extraídos com solventes mais polares. Por outro lado, apenas um dos extratos (2B) apresentou atividade inibitória no crescimento micelial do fitopatógeno testado.

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Bachelors
Engineering and Computer Science
Electrical Engineering

O araçá é um fruto, pertencente à espécie Psidium grandifolium Mart. ex DC, nativo da mata atlântica brasileira pouco caracterizado pela literatura ciêntífica. Esta pesquisa visou estudar o rendimento de extração e avaliar as atividades antioxidante e antimicrobiana do óleo essencial de araçá obtido por extração com dióxido de carbono supercrítico (SFE) e dos diferentes extratos obtidos por extração com etanol pressurizado (PLE) seguindo um delineamento composto central rotacional com temperatura e tempo estático como variáveis independentes estudadas. Avaliou-se também o perfil de voláteis do óleo essencial, o teor de compostos fenólicos totais dos extratos etanólicos e as alterações causadas na matriz vegetal por diferentes processos de extração. Com a SFE conseguiu-se extrair toda a fração lipídica do fruto (2,33% ± 0,04.10-2%), a análise dos compostos voláteis do óleo essencial obtido permitiu inferir que este possui diversos compostos com potencial bioativo tais como E-cariofileno (17.56%), α-humuleno (16,26%) e β-sesquifelandreno (14.27%); porém este óleo essencial não apresentou atividade antioxidante relevante. O extrato etanólico com maior rendimento (17, 49%) foi obtido a 74 °C por 6 min, mesma condição em que obteve-se a maior atividade antioxidante (EC50 = 6,37 mg/mL), porém o maior teor de compostos fenólicos totais (136,95 mg EGA/100 g de massa seca) foi obtido quando aplicou-se 60°C por 9 min. Em relação à atividade antimicrobiana, tanto os extratos obtidos por PLE quanto por SFE apresentaram atividade contra cepas de P. aeruginosa, S. aureus e B. cereus, somente extratos etanólicos apresentaram atividade contra cepas de L. monocytogenes e nenhum dos extratos apresentaram atividade contra cepas de B. subtilis, E. coli e Salmonella. Em ambos os extratos foi possível identificar compostos com potencial aplicação farmacológica. O estudo de processos de extração que envolvam inovação tecnológica na obtenção extratos com atividade biológica visa contribuir com o extrativismo consciente ou estimular o plantio em maior escala de mais um fruto tropical empregado na medicina popular brasileira.
The araçá is a fruit, belonging to the species Psidium grandifolium Mart. ex DC, native of the Brazilian Atlantic Forest, is not largely characterized by the scientific literature. This research work aimed to study the extraction yield and to evaluate the antioxidant and antimicrobial activities of the araçá essential oil obtained by supercritical carbon dioxide extraction (SFE) and the different extracts obtained by pressurized ethanol extraction (PLE) following a central composite design with temperature and static time as independent variables studied. It was also evaluated the volatile profile of the essential oil, the content of total phenolic compounds of the ethanolic extracts and the changes caused in the vegetal matrix by different extraction processes. SFE was able to extract the whole lipid fraction of the fruit (2.33% ± 0.04.10-2%), the analysis of the volatile compounds of the essential oil obtained allowed to infer that it has several compounds with bioactive potential such as E-caryophyllene (17.56%), α-humulene (16.26%) and β-sesquipelandene (14.27%); but this essential oil had no relevant antioxidant activity. The highest ethanolic extract (17, 49%) was obtained at 74 °C for 6 min, the same condition in which the highest antioxidant activity was obtained (EC50 = 6.37 mg/mL), but the higher content of total phenolics contente (136.95 mg EGA / 100 g dry mass) was obtained when 60 °C was applied for 9 min. In relation to the antimicrobial activity, both extracts obtained by PLE and SFE showed activity against P. aeruginosa, S. aureus and B. cereus strains, only ethanolic extracts showed activity against L. monocytogenes strains and none of the extracts presented activity against B. subtilis, E. coli and Salmonella strains. In both extracts it was possible to identify compounds with potential pharmacological application. The study of extraction processes that involve technological innovation in obtaining extracts with biological activity aims to contribute to the conscious extraction or stimulate the larger scale cultivation of another tropical fruit used in Brazilian popular medicine.

El objetivo de la investigación fue determinar el efecto anticonceptivo y postcoital del extracto etanólico de Desmodium molliculum en ratas hembras adultas Holtzmann. La muestra fue de 80 ratas hembras seleccionadas de acuerdo a los criterios de inclusión, y divididas en 2 grupos, estando cada uno conformada por 5 subgrupos de 8 ratas hembras y ratas machos para el emparejamiento (1 macho: 2 hembras). 1) Grupo 1: 40 ratas para la evaluación del efecto anticonceptivo del extracto de Desmodium molliculum a una solución 100mg/mL vía oral en dosis 200mg/kg, 600mg/kg y 1000mg/kg. Se utilizaron dos grupos como controles suero fisiológico y Medroxiprogesterona en dosis 15mg/kg; 2) Grupo 2: 40 ratas para la evaluación del efecto post-coital del extracto Desmodium molliculum 100mg/mL vía oral a dosis 200mg/kg, 600mg/kg y 1000mg/kg. Se utilizaron dos grupos como controles suero fisiológico y Levonorgestrel a dosis de 50ug/kg. El efecto anticonceptivo se evaluó mediante la cuantificación de los indicadores gravidez, número de implantaciones y número de fetos; el efecto post-coital se evaluó mediante la cuantificación de los indicadores gravidez, número de implantaciones, número de fetos vivos y número de fetos muertos. El análisis estadístico fue realizado empleando el software SPSS versión 16.0 año 2009 para Windows. Se realizaron análisis descriptivos y pruebas estadísticas de significancia ANOVA.y Tukey Los resultados encontrados demuestran que el extracto etanólico de Desmodium molliculum tiene un efecto anticonceptivo y post-coital. En conclusión, bajo las condiciones experimentales, de esta investigación el extracto etanólico de Desmodium molliculum ha demostrado efecto anticonceptivo y poscoital en ratas Holtzmann hembras.
The objective of this research was to determine the postcoital contraceptive effect and the ethanol extract of Desmodium molliculum Holtzmann adult female rats. The sample was 80 female rats selected according to inclusion criteria, and divided into 2 groups, each being made up of 5 sub-groups of 8 male rats and female rats for mating (1 male: 2 females). 1) Group 1: 40 rats to evaluate the contraceptive effect of the extract of Desmodium molliculum 100mg/mL a solution orally at 200mg/kg, 600mg/Kg and 1000mg/kg. Two groups were used as controls saline and 15mg/kg dose medroxyprogesterone, 2) Group 2: 40 rats for assessment of post-coital effect of the extract Desmodium molliculum 100mg/mL 200mg/kg oral dose, and 600mg/Kg 1000mg/kg. Two groups were used as saline controls and a dose of Levonorgestrel 50ug/kg. The contraceptive effect was assessed by quantitative indicators pregnancy, number of implantations and number of fetuses, the post-coital effect was assessed by quantitative indicators pregnancy, number of implantations, number of live fetuses and number of fetuses. Statistical analysis was performed using the SPSS software version 16..0 2009 for Windows. Descriptive analysis was performed and statistical tests of significance ANOVA.y Tukey The results show that the ethanol extract of Desmodium molliculum has a post-coital contraceptive and. In conclusion, under experimental conditions of this study the ethanolic extract of Desmodium molliculum demonstrated and post-coital contraceptive effect in female rats Holtzmann
Tesis

Demuestra el efecto cicatrizante del extracto hidroalcohólico de Ranunculus praemorsus H.B.K. ex DC, en lesiones inducidas en ratas. Presenta una investigación de diseño experimental realizada en la Facultad de Medicina y de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos. Los materiales biológicos son extracto, ratas y ratones albinas. Realoza un estudio fitoquímico preliminar, lesiones y toxicidad. Para la actividad cicatrizante se preparó concentraciones de 1%, 5%,10%, 20%, dosis vía oral 10 mg/kg, 50 mg/kg, 100 mg/kg, 200 mg/kg respectivamente, grupo patrón Croton Lechleri Muell al 95%, 160 mg/kg, y grupo control “crema base”. Al onceavo día se tomaron fotografías de las heridas en dichas imágenes fotográficas se usó el planímetro para medir el área de la reducción de las heridas, permitiendo el cálculo del área de curación de heridas y los anatomopatológicos evidenciaron el efecto cicatrizante. Evaluación toxicológica a dosis límite del extracto en ratones, no causó mortalidad a la dosis máxima de 2000 mg/kg de peso. Se identificaron alcaloides, triterpenos, esteroides y flavonoides. El tratamiento con mayor eficacia fue el extracto total por vía tópica 36.33%, seguido de concentración al 20% vía tópica y dosis de 200 mg/kg vía oral fue de 31.33%, en comparación con el grupo patrón Croton lechleri Muell que fue de 40.66% (p<0.05). Se demostró el efecto cicatrizante del extracto hidroalcohólico por vía tópica en ratas y se evaluó la toxicidad aguda a dosis límite de 2000 mg/kg, no se produjo mortalidad.
Tesis

El tomate de cascara (Physalis ixocarpa Brot.) también llamado tomate, tomate verde, tomate de hoja, tomate de fresadilla, tomate de bolsa y tomatillo es conocido desde las épocas prehispánicas por los mayas, teotihuacanos, aztecas, purépechas, etc., siendo México su centro de origen y domesticación. Esta hortaliza pertenece a la familia Solanácea y subfamilia Solanoideae tribu Solaneae (contempla 18 géneros). Su cultivo no requiere de cuidados muy demandantes, sin embargo se ha visto afectado por la presencia de enfermedades y plagas. Aunque existen infinidad de plagas e insectos plaga, de las que atacan al cultivo destacan: la mosca blanca (Bemisia tabaci), que origina amarillamiento de la planta, abortó floral; trips (Franklinella occidentalis Pergante) que causa la deformación de frutos y mala calidad para su comercialización. Aunque existen diferentes tipos de control para este tipo de insectos plagas, tanto de origen químico como las convencionales, el uso de extractos vegetales ha tomado una mayor relevancia agrícola para el control de plagas y es cada vez más aceptado debido a la necesidad de emplear compuestos eficaces que no provoquen efectos secundarios en la salud humana. Con la idea de mejorar la practica en el cultivo del tomate verde, se realizó el presente trabajo para determinar el efecto de extractos vegetales de ortiga (Urtica dioica), chicalota (Argemone mexicana L.), ruda (Ruta graveolens L.), Toloache (Datura stramonium L.) y estafiate (Ambrosia confertiflora DC.), más el agua como testigo. Los extractos mostraron un efecto repelente en las plagas que afectan al tomate de cascara; para mosca blanca, el extracto de chicalota originó la menor área bajo la curva en las diferentes fechas de muestreo. En el caso de trips los menores valores de captura y área bajo la curva se presentaron con los extractos de ortiga y chicalota. El rendimiento obtenido con los extractos fue similar al testigo. Los extractos de plantas nativas del Valle de Toluca representan una excelente alternativa sustentable (manejo orgánico) para el control de plagas.

Evalúa el efecto quimioprotector del extracto etanólico de la corteza de Tabebuia impetiginosa (Mart ex Dc.) Standley “guayacán” en cáncer de próstata inducido en ratas. El trabajo experimental se realizó en el Laboratorio de Farmacología, Bioterio "San Fernando" de la Facultad de Medicina Humana, UNMSM. Se utilizaron 30 ratas, distribuidas en 5 grupos de 6 unidades. Grupo I: se administró solución fisiológica al 0,9 %; grupo II: NMU + testosterona. Los grupos III, IV y V recibieron el NMU + extracto etanólico resuspendido en dosis de 50, 250 y 500 mg/kg; respectivamente. Se aplicó 0,2 mL de NMU como inductor del cáncer por una sola vez. Luego se administró testosterona más el extracto a las ratas de los grupos III, IV y V durante cuarenta semanas. Al finalizar se extrajo sangre mediante punción cardiaca a todos los grupos para los exámenes auxiliares de hemograma, perfil hepático, lipídico y renal, antígeno prostático, proteína C reactiva, SOD y glucosa y las observaciones macroscópicas e histológicos de las próstatas. El análisis se hizo por el método cromatografía líquida acoplada a espectrometría de masas, se identificó compuestos orgánicos como catalpol (6-0-(4- Hydroxybenzoil), aucubigenina, oleanólico ácido. Tabebuia impetiginosa reduce la PCR hasta 78 % (p<0,0062) asimismo, el PSA 33%. (<0,0062). Apreciándose un efecto quimioprotector con el extracto al inducir hasta hiperplasia con hipoplasia moderada. Concluye que se ha identificado compuestos químicos: catalpol, aucubina, impetiginósido A y ácido oleanólico, y se demuestra el efecto quimioprotector del cáncer de próstata inducido en ratas.

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Evalúa el efecto antiinflamatorio y diurético del extracto etanólico, de la corteza de Tabebuia impetiginosa (Mart. Ex DC) Standley “Guayacán”, en un modelo in vivo de ratas. Se utilizan 72 ratas, divididos aleatoriamente en 12 grupos. Se prepara el extracto a diferentes a dosis de 50, 250 y 500 mg/Kg; ibuprofeno 20 mg/Kg; dexametazona 20 mg/Kg; furosemida de 20 mg/kg; hidroclorotiazida 20mg/kg. Se administran los extractos por vía oral. Se provoca inflamación a media hora, de administrar soluciones extractos. Inyectando 0,2 mL solución acuosa de λ-Carragenina al 1% en patas derecha de ratas. Siguiendo el modelo Arroyo et al, 2012. Grupo I: suero fisiológico al 0,9% (2mL/kg), grupo II: hidroclorotiazida (20mg/kg), grupo III: furosemida (20 mg/kg), los grupos IV, V, y VI: extracto etanólico de Tabebuia impetiginosa a dosis de 50, 250, 500 mg/kg, respectivamente. Las ratas son colocadas en jaulas metabólicas individuales para recolectar la orina (24h) y cuantificar electrolitos excretados (Na+, K+ y Cl-).
Tesis

Determina el efecto antioxidante del extracto hidroalcohólico de hojas de Jungia paniculata (DC.) A. Gray “matico serrano” sobre el tejido gástrico de ratas injuriado por etanol 70%. Se preparó un extracto hidroalcohólico 70% de hojas estabilizadas. La capacidad antioxidante se evalúa mediante DPPH. Se distribuyen aleatoriamente 24 ratas Sprague - Dowley en 4 grupos: I (NaCl - NaCl), II (NaCl - EtOH), III (Extracto 600 mg/kg – EtOH) y IV (Extracto 600 mg/kg – NaCl), según el método de Robert et al., (1979). El estómago es obtenido por laparotomía, para lo cual se preparó un homogenizado de la parte glandular y se centrifugó a 2 000 RPM x 5’, las pruebas bioquímicas se realizaron en el sobrenadante: cuantificación de GSH reducido y total, medición de especies reactivas al ácido tiobarbitúrico (TBARS), actividad específica de superóxido dismutasa (SOD) y catalasa (CAT). La toxicidad aguda se evalúa a dosis límite. Encuentra que el extracto presenta una capacidad antioxidante de IC50 4,15 µg/mL en comparación a Vitamina C 2,29 µg/mL y Trolox 3,38 µg/mL. Observa un incremento de GSH reducido y total en el grupo IV. Los niveles de TBARS están significativamente disminuidos en III y IV. Hay recuperación significativa de La SOD en los grupos III y IV respecto al grupo II. No hay variación significativa en la actividad específica de CAT. Con respecto a la toxicidad aguda resulta ser no dañina. Concluye que el extracto hidroalcohólico tiene buena actividad antioxidante y presenta efecto gastroprotector, previniendo la lipoperoxidación e incrementando la capacidad antioxidante (GSH y SOD).
Tesis

碩士
國立交通大學
電控工程研究所
107
In recent years, climate changing and awareness of environmental protection have led the development of green economy. Many new technologies have been applied to reduce CO2 emissions and transform CO2 into useful organic or inorganic carbon sources in our environment. Soil battery uses soil as an important medium for microbial nutrient replenishment. If soil battery can combine with microbes, it will be conducive to develop green energy systems achieving environmental and energy development. Therefore, this article will focus on exploring the photosynthetic microbial soil energy. To achieve sustainable agricultural and energy development, this study will make use of the function of photosynthetic microbes to capture carbon. However, microbial soil batteries suffer from the following problems, the difference of soil, variation number colonies of bacteria, and electrode aging. To design a dedicated voltage converter, it is necessary to add a mechanism for energy judgment in order to selecting the most appropriate input to expand high efficiency range. Nevertheless, smart energy delivery and storage is necessary for the changing of the battery sources. Due to the large power consumption of the environmental sensors and wireless transceivers, the soil energy is not sufficient to supply the entire wireless sensing system. The proposed upper and lower regulation controller controls the power switch between output of the dc-cd converter and load for a large sudden load current (>20mA) and regulates the output voltage between 1.7 and 1.8V. Using the charging and discharging conditions of the reference capacitance balance the input and output power requirement, further increasing high efficiency for a wide load range. The proposed capacitive DC-DC converter with maximum power point tracking for soil energy extraction is fabricated in a 0.18μm CMOS process. The goal is to propose a capacitive DC-DC converter with dynamically adjusting input source, to expand a wide range of high efficiency over the wide load range, and also build an energy storage mechanism to store and utilize excess energy. The design achieves a tracking efficiency of 87.1% in the output power range from 160 µW to 2.5mW and the peak system efficiency of 86.6%.

碩士
國立交通大學
電子工程學系 電子研究所
103
In this thesis, the impacts of the layout dependent effects on the nanoscale device performances, will be investigated in a variety of the device layouts. In order to achieve the higher maximum oscillation frequency (fMAX) and the lower RF noise, the multi-finger (MF) devices with the simultaneously varied finger width (WF) and finger number (NF), for an effective reduction of gate resistance (Rg), have been widely adopted in the modern RF circuit designs. However, the multi-finger devices with the continuous scaling of WF will suffer the undesired increase of the compressive stress from STI, which leads to the lower effective electrons mobility (ueff) and thereby the lower transconductance (gm). Moreover, the increase of NF will result in the increase of the total gate capacitance (Cgg) due to the poly-finger-end fringing capacitance (Cf(poly-end)). To facilitate a reliable verification of the impact from the STI stress and other layout dependent effects like effective doping concentration on eff, an accurate extraction of the source line resistance (RS), the effective channel width (Weff), and the gate length (Lg) is mandatory to realize accurate eff extraction. The RS can be calculated by our developed distributed transmission line (TML) model, and the results indicate that the larger NF and narrower WF leads to the higher RS due to the narrower and longer source line. Without taking RS into account will lead to underestimate of the extracted eff. As for Lg and Weff, they can be extracted by using our proprietary high precision capacitance method based US patent 8,691,599 B2「Parameter Extraction Method for Semiconductor Device」. To reduce RS and STI transverse stress, there are two new layouts, such as multi-group (MG) and multi-ring (MR) devices, proposed and implemented in this thesis. In addition to eff, the layout dependent threshold voltage (VT) and drain induced barrier lowering (DIBL) have been investigated as well. In our experimental, the single-finger (SF) devices with the largest lateral STI stress reveal much higher VT than all MF devices, and it suggests the retardation of boron diffusion caused by the compressive stress. Regarding DIBL, the experimental results indicate that the narrower WF will bring about the benefit of the suppression of DIBL due to the corner fringing field coupling from the drain to the poly-gate extension. In Chapter 3, a new analytical VT model incorporating 3-D DIBL effect has been developed to predict the WF scaling effects in DIBL. Furthermore, the suppressed boron diffusion may reduce the source/drain extension (SDE) overlap length (LSDE). In Chapter 4, This influence of layout dependent stress on LSDE has be verified and proven by our new method for an accurate extraction of LSDE and RSDE. Finally, in Chapter 5, the layout dependent effects in high frequency characteristics such as the cut-off frequency (fT) and fMAX will be demonstrated and investigated. The abnormal layout dependence revealed in the Rg extracted by the conventional Y-method suggests that the non-negligible parasitic elements like RS and the source inductance (LS) in a 4-terminal (4T) MOSFET should be taken into account. An improved Rg extraction method to be valid for 4T MOSFETs becomes an interesting and challenging work in the future. Regarding fT and fMAX, it is found that the larger NF and smaller WF intended to reduce Rg generally leads to lower fT, due to a significant increase of Cgg, and further impact on fMAX , even if the reduced Rg may improve fMAX in some cases. Thus, the solutions for the optimized device layouts deserve an extensive research efforts in the future.

Mestrado de dupla diplomação com Universidad Tecnológica Nacional, Facultad Regional Cordoba
From the Industrial Revolution, humanity has been suffering the consequences of a system that only focus on economic growth, neglecting environment quality and, consequently, population’s health. Horticulture is one of the industrial sectors where the greatest amount of organic waste is generated. These biowastes are further discarded and devalued. However, these by-products are excellent sources of pigments, phenolic compounds, dietary fibres, sugar derivatives, organic acids, minerals and vitamins. All these compounds have health beneficial properties, so their reuse is an effective and promising alternative for industry and environment. Many authors have studied different vegetable matrices and found molecules of high industrial interest in their composition. Due to its high vitamin C, carotenoids and anthocyanins content, Malpighia emarginata DC. (acerola) is known for its nutritional and functional properties. In this work the nutritional and chemical characterization of M. emarginata bioresidues were studied, as well as the evaluation of bioactive potential. Furthermore, a study of extraction optimized process was performed, in order to obtain a natural colourant pigment rich in anthocyanins. The nutritional profile was determined using official methodologies for the analysis of food products (AOAC) and the results showed the carbohydrates as the predominant macronutrient and low values of fat content. The chemical profile was evaluated determining free sugars by HPLC-RI, organic acids by UFLC-PDA, fatty acids by GC-FID and phenolic compounds (anthocyanin and non-anthocyanin) by HPLC-DAD-ESI/MS. Fructose, glucose and sucrose were identified, highlighting fructose as the main free sugar compound. Also, oxalic, malic, ascorbic and succinic acids were identified, being malic acid the most abundant organic acid. The fatty acids profile revealed the presence of fourteen compounds, being mostly represented by saturated fatty acids, with oleic acid as the majority. The phenolic composition evidenced the presence of six non-anthocyanin compounds and two anthocyanins, standing out the isorhamnetin-O-pentosyl-hexoside and cyanidin-O-deoxyhexoside as the major compounds, respectively. The bioactive potential was evaluated throught antioxidant activity by TBARS and OxHLIA methodologies; antimicrobial activity was determined by the microdilution method using clinical isolated from Gram-positive and Gram-negative bacteria and a fungi strain; cytotoxicity was tested in four human tumour cell lines (MCF-7, NCI-H460, AGS and CaCo) and in a non-tumour primary cell culture (PLP2), using sulforrodamine B assay. Finally, anti-inflammatory activity was determined in RAW264.7 cells. Based on the obtained values, the presence of antioxidant and anti-inflammatory action was demonstrated. Also, the antimicrobial activity revealed promising results, with good bacteriostatic and fungistatic effects. Concerning cytotoxic evaluation, the extract revealed a greater capacity to inhibit the half tested tumour cell lines than to inhibit non-tumour cells. Subsequently, the heat assisted extraction (HAE) methodology was used for the extraction optimization process, applying the response surface analysis method (RSM). In this study it was found that the optimal extraction conditions for obtaining an extract rich in anthocyanin compounds were: t = 24.8 min, T = 40.5°C and % ethanol = 11.8. The HAE extraction process showed a relevant yield value of 57.1%, being quantified a total anthocyanins content of 2.54 mg/g extract. Overall, this study highlights the excellent composition in compounds of interest and bioactive potential of M. emarginata fruits, as well as, its potential as an alternative and promising source of anthocyanin compounds.
Com o evoluir do tempo, a humanidade tem vindo a acompanhar as consequências de um sistema remanescente da Revolução Industrial que, por visar apenas a produtividade com foco no crescimento económico, descurou a qualidade do ambiente e, consequentemente, a saúde da população. A hortofrutícultura é um dos sectores industriais onde se gera maior quantidade de resíduos orgânicos, que são descartados e desvalorizados. Contudo, esses subprodutos são excelentes fontes de pigmentos, compostos fenólicos, fibras alimentares, derivados de açúcar, ácidos orgânicos, minerais e vitaminas que possuem propriedades benéficas à saúde, sendo o seu reaproveitamento uma alternativa eficaz e promissora para a indústria e para o ambiente. São várias a matrizes vegetais que têm vindo a ser estudadas por diversos autores, que constataram a sua interessante composição em moléculas de elevado interesse para o setor industrial. Malpighia emarginata DC. (acerola) é um fruto conhecido pelas suas propriedades nutricionais e funcionais, devido ao seu elevado conteúdo de vitamina C, carotenóides e antocianinas. Neste trabalho foi estudada a caracterização nutricional e química de biorresíduos de M. emarginata, bem como a avaliação do seu potencial bioativo. Além disso, foi realizado um estudo do processo de otimização da extração, a fim de se obter um pigmento corante natural rico em antocianinas. O perfil nutricional foi determinado através de metodologias oficiais para análise de produtos alimentares (AOAC), e os resultados mostraram os hidratos de carbono como o macronutriente predominante e baixo teor de gordura. O perfil químico foi avaliado determinando os açúcares livres por HPLC-RI, os ácidos orgânicos por UFLC-PDA, os ácidos gordos por GC-FID e os compostos fenólicos (antociânicos e não antociânicos) por HPLC-DAD-ESI/MS. Foram identificados frutose, glucose e sacarose, destacando-se a frutose como o principal composto de açúcares livres. Também foram identificados os ácidos oxálico, málico, ascórbico e succínico, sendo o ácido málico o ácido orgânico mais abundante. O perfil de ácidos gordos revelou a presença de catorze compostos, tendo sido na sua maioria representados por ácidos gordos saturados, com o ácido oleico como maioritário. A composição fenólica evidenciou a presença de seis compostos não antociânicos e dois antociânicos, destacando-se a isoramnetina-O-pentosil-hexosídeo e a cianidina-O- desoxihexosídeo como compostos maioritários, respectivamente. O potencial bioativo foi avaliado através da atividade antioxidante pelas metodologias TBARS e OxHLIA; a atividade antimicrobiana foi determinada pelo método de microdiluição utilizando isolados clínicos de bactérias Gram-positivos e Gram-negativos e uma estirpe de fungo; a citotoxicidade foi testada em quatro linhas de células tumorais humanas (MCF-7, NCI-H460, AGS e CaCo) e numa cultura de células primárias não tumoral (PLP2), utilizando o ensaio de sulforrodamina B. Finalmente, a atividade antiinflamatória foi determinada em células RAW264.7. Com base nos valores obtidos, foi demonstrada a presença de ação antioxidante e antiinflamatória. Também a atividade antimicrobiana revelou resultados promissores, com bons efeitos bacteriostáticos e fungistáticos. Relativamente à avaliação citotóxica, o extracto revelou uma maior capacidade de inibir as linhas de células tumorais testadas do que de inibir as células não tumorais. Posteriormente, a metodologia de extração assistida por calor (HAE) foi utilizada para o processo de otimização da extração, aplicando-se o método de análise de superfície de resposta (RSM). Neste estudo verificou-se que as condições ótimas de extração para a obtenção de um extrato rico em compostos antocianínicos foram: t = 24.8 min, T = 40.5°C e % etanol = 11.8%. O processo de extração de HAE apresentou um valor relevante de rendimento de 57.1%, sendo quantificado um teor total de antocianinas de 2.54 mg/g de extrato. No geral, este estudo destaca a excelente composição em compostos de interesse e o potencial bioativo de M. emarginata frutas, bem como, o seu potencial como fonte alternativa e promissora de compostos antociânicos.

碩士
國立成功大學
化學系
85
The characteristics of supercritical carbon dioxide extraction technologyare low extraction temperature and high diffusibility . The advantages of thisproperties when applied to the extracting of the thermally unstable substancesfrom the essential oil are faster extraction rate and high extraction yieldswithout losing itsfragrance. In this study , two methods were used to evaluatemaximum essential oil yield of Michelia alba DC. flowers by supercritical carbon dioxide , one is " altering one factor at a time method " , in the other is "Taguchi method" with the " steepest ascent method " . By the " altering one factor ata time method" , the result showed thatthe best yield of essential oilis 6.76%, which is better than any other conventional extraction method . In addition to , the color of the essential oil would not change by supercritical carbon dioxide extraction after being stored in refrigeratorfor five months.The chemical components of essential oils extracted by supercritical carbon dioxide was identified with GC-MS . Nine major compounds wereidentified in the essential oil of Michelia alba DC. flowers , such as :3-Methyl-butanoic acid , Benzyl methyl ether , Linalool oxide , Linalool , Phenyl ethyl alcohol , 2,6-Dimethyl-3,7- octadiene-2,6-diol , 4-Hydroxy-benzaldehyde , Vanillin and Squalene . By the " Taguchi method " , a L12(11) orthogonal array was chosen to investigate the yield of essential oil and linalool oxide and the main fragrant components-linalool. According to the "analysis of variance table " ,collection temperature was the most significant factor . Furthermore , a " steepest ascent method " was used to gain the highest yield . Extraction temperature and the density of carbon dioxide were chosen as variables. The results showed a 11.84% yield of essential oil was achieved.According to this method , the optimum condition to extract linalool was following : extraction temperature 66.6oC , and the density of carbon dioxide 0.632 g/ml . Both " altering one factor at a time method " and " experimental design method "indicated that the yield of extracting essential oil from Michelia supercritical carbon dioxide were higher than any other technique . Furthermore , "experimental design method" can reduce experimental time , and it could offer us a completely way to optimize the extraction parameters .

Control and monitoring networks often operate on AC/DC power systems. DC batteries and chargers are commonly used on industrial plants as auxiliary DC power systems for these control and monitoring networks. The energy demand and load profiles for these control networks differ from application to application. Proper design, sizing, and maintenance of the components that forms part of the DC control power system are therefore required. Throughout the load profile of a control and monitoring system there are various peak currents. The peak currents are classified as inrush and momentary loads. These inrush and momentary loads play a large role when calculating the required battery size for an application. This study investigates the feasibility of using supercapacitors in conjunction with batteries, in order to reduce the size of the required battery capacity. A reduction in the size of the required battery capacity not only influences the cost of the battery itself, but also influences the hydrogen emissions, the physical space requirements, and the required rectifiers and chargers. When calculating the required size batteries for an auxiliary power system, a defined load profile is required. Control and monitoring systems are used to control dynamic processes, which entails a continuous starting and stopping of equipment as the process demands. This starting and stopping of devices will cause fluctuations in the load profile. Ideally, data should be obtained from a live plant for the purpose of defining load profiles. Unfortunately, due to the economic risks involved, installing data logging equipment on a live industrial plant for the purpose of research, is not allowed. There are also no historical data available from which load profiles could be generated. In order to evaluate the influence of supercapacitors, complex load profiles are required. In this study, an alternative method of defining the load profile for a dynamic process is investigated. Load profiles for various applications are approximated using a probabilistic approach. The approximation methodology make use of plant operating philosophies as input to the Markov Chain Monte Carlo simulation theory. The required battery sizes for the approximated profiles are calculated using the IEEE recommended practice for sizing batteries. The approximated load profile, as well the calculated battery size are used for simulating the auxiliary power system. A supercapacitor is introduced into the circuit and the simulations are repeated. The introduction of the supercapacitor relieves the battery of the inrush and momentary loads of the load profile. The battery sizing calculations are repeated so as to test the influence of the supercapacitor on the required battery capacity. In order to investigate the full influence of adding a supercapacitor to the design, the impact on various factors are considered. In this study, these factors include the battery size, charger size, H2 extraction system, as well as maintenance requirements and the life of the battery. No major cost savings where evident from the results obtained. Primary reasons for this low cost saving are the fixed ranges in which battery sizes are available, as well as conservative battery data obtained from battery suppliers. It is believed that applications other than control and monitoring systems will show larger savings.
MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

Στην παρούσα εργασία υλοποιούμε ένα σύστημα δημιουργίας περιλήψεων από ακολουθίες βίντεο. Υλοποιούνται όλα τα βήματα που θα πρέπει να ακολουθηθούν (εξαγωγή χαρακτηριστικών-ανίχνευση πλάνων-εξαγωγή χαρακτηριστικών καρέ) έτσι ώστε να εξαχθεί ένα σύνολο καρέ (χαρακτηριστικά καρέ) τα οποία να συνοψίζουν νοηματικά το περιεχόμενο μιας ακολουθίας βίντεο. Η επεξεργασία του βίντεο γίνεται απευθείας στο συμπιεσμένο πεδίο και συγκεκριμένα σε συμπιεσμένα αρχεία MPEG-1-2, έτσι ώστε τα αποτελέσματα να εξάγονται σε σχετικά μικρό χρόνο και με σχετικά χαμηλές απαιτήσεις σε αποθηκευτικό χώρο και επεξεργαστική ισχύ.
In this paper a video summarization system is being constructed. We acomplish all the needed steps (feature extraction -shot detection-keyframe extraction) in order to extract a set of frames (keyframes) that capture the semantic content of the video sequence. The processing of the video takes place directly at the compressed domain (at MPEG-1-2 video files). Thus we obtain results at relatively little time and with relatively low storage and computer power demands.

This master's thesis is focused on the determination of 6-thioguanine (6-T) by DC voltammetry (DCV), differential pulse voltammetry (DPV) and flow injection analysis with electrochemical detection (FIA-ED) on a boron doped diamond electrode (BDDFE). The optimum conditions for determination of 6-T were found and under these conditions, concentration dependences were measured and the limits of quantification (LOQ) were calculated for each method. Medium of 60% methanol and phosphate buffer (PB) pH 2,0 was chosen as optimum for DCV and DPV determination of 6-T at BDDFE. For both DCV and DPV, the linear concentration dependences were obtained in concentration ranges of 6-T from 2 µmol·l-1 to 10 µmol·l-1 with LOQ 0,9 µmol·l-1 for DCV and 1,5 µmol·l-1 for DPV. Lower LOQ was achieved in PB pH 2,0, where LOQ was 0,6 µmol·l-1 for both DCV and DPV, but the problem was lower repeatability. In PB pH 2 6-T was determined by DCV in drinking and river water with LOQ 1,3 µmol·l-1 in both drinking and river water. The possibility of solid phase extraction was investigated as a method for preliminary separation of 6-T from urine. For FIA under optimized conditions (polarization potential 1300 mV, flow rate 5 ml·min1 and sample volume 50 µl) the linear concentrations dependences were obtained in concentration ranges...

of the Diploma Thesis In this Diploma Thesis, the electrochemical behavior of 4-nitrophenol (4-NP) was studied at a newly prepared large-surface carbon film electrode (ls-CFE) using techniques of DC voltammetry (DCV) and differential pulse voltammetry (DPV) with the aim to develop sensitive analytical methods for its determination. Voltammetric behavior of 4-NP was investigated in the region of anodic potentials, in dependence on the pH of the medium used (realized using Britton-Robinson buffer). The optimum pH values for the determination of 4-NP were chosen as follows: pH 3.0 (for DCV) and pH 7.0 (for DPV). During anodic oxidation of 4-NP on the ls-CFE at the concentration of the analyte of 1·10-4 mol/l, the passivation of the electrode surface occurred. Thus, it was decided to record series of measurements always at a new carbon film. Using the sample of 4-NP (at the concentration of 1·10-4 mol/l), the repeatability of the application of individual carbon films was tested, with obtained RSD values of 3.7% and 3.6% for DCV and DPV, respectively. Under optimum conditions, the calibration dependences of 4-NP were measured in the concentration range from 1·10-6 to 1·10-4 mol/l, with the limits of quantification (LQs) of 1.5·10-6 mol/l (for DCV at the ls-CFE) and 4.6·10-7 mol/l (for DPV at the...

Tese de doutoramento em Ciências Farmacêuticas, na especialidade de Farmacognosia e Fitoquímica, apresentada à Faculdade de Farmácia da Universidade de Coimbra
Cymbopogon citratus (DC). Stapf (Poaceae), commonly known as lemongrass, is a tropical perennial shrub originated from the Southeast Asia. This plant is reported to possess antifungal, insecticidal, anti-diabetic, anti-septic, anti-mutagenic, anti-carcinogenic activities as well as anti-inflammatory. In fact, aqueous extracts of dried leaves are used all over the year in folk medicine for the treatment of peptic ulcers and inflammatory conditions. Recently, some phenolic compounds, such as luteolin and apigenin glycosides and condensed tannins, were identified and related to both antioxidant and anti-inflammatory properties. The purposes of this work were to i) validate an analytical method for quantification of phenolic compounds of C. citratus; ii) study the influence of harvest time and plant quality on the phenolic composition and antioxidant activity; iii) characterize the tannins; iv) validate the traditional uses of lemongrass infusion as anti-inflammatory in vivo; v) obtain a topical formulation to evaluate the phenolic compounds permeation and their anti-inflammatory activity; vi) trace the pharmacokinetic profile of the main phenolic compounds in rats. Three different extracts: infusion (CcI), 50% aqueous ethanol (CcM50%) and ethanol (CcM100%) extracts were prepared and a simple and efficient RP-HPLC-PDA method was successfully validated for simultaneous identification and quantification of phenolic acids and flavonoids. Infusions were also obtained from different harvest dates (April, June, July, August and September) and quality grades (High, Medium and Low). It was verified that the content on polyphenols and the antioxidant capacity of CcI is strongly related with the quality of the plant. The total phenols assay showed a substantial loss from August to September. It was possible to find out the best month to harvest the plant to get the most of each phenolic group: April and June for hydroxycinnamic acids; June and September for flavonoids; June, July and August for tannins. Regardless the group of phenolic compound addressed, its content was always inversely proportional to the degree of leaves ageing. For all tested oxidant species, the high-quality samples exhibited the best antioxidant results. CcI was fractionated by column chromatography and polyphenol-rich fractions, namely phenolic acids (CcPA), flavonoids (CcF) and tannins (CcT) were obtained. CcT was characterized by HPLC-PDA-ESI/MSn, revealing the presence of proanthocyanidin hetero-dimers, along with some common procyanidin dimers. These hetero-dimeric flavan structures have been described for the first time in lemongrass and consist of apigeniflavan or luteoliflavan units linked to a flavanone, either naringenin or eriodictyol, and may occur as aglycone or glycosylated forms. For the in vivo assays, CcI, CcF and CcT were tested. CcI administered before and after ethanol stimulus, significantly reduced the incidence and severity of gastric lesions and, consequently, the ulcer index, corroborating the traditional medicinal use of this plant to ameliorate gastritis and/or peptic ulcers symptoms. On the other hand, CcI, CcF and CcT were orally administered to rats, in order to evaluate the anti-inflammatory effect at the carrageenan-induced paw edema assay. The observed effect by CcI (68.24 mg/kg), 82.30% of edema inhibition, was very similar to that obtained by the reference NSAID used (diclofenac, 10 mg/kg), 84.00%. On the other hand, flavonoid (7.42 mg/kg) and the tannin-rich (5.96 mg/kg) fractions significantly contributed for the anti-inflammatory activity on the edema volume (59 and 61%, respectively). The topical anti-inflammatory activity of CcI was also addressed. The results suggest that flavonoids, mainly, luteolin 7-O-neohesperidoside, cassiaoccidentalin B, carlinoside and cynaroside, may contribute to the topical anti-inflammatory effect. CcF (0.6%), CcT (0.3%) and CcF+CcT (0.66%+0.34%) topical formulations were also tested, and the results obtained suggest that tannins and flavonoids also possess a significant activity and that a synergistic mechanism of action may occur. In fact, edema inhibitions of 43%, 47% and 59% were respectively verified, being CcF+CcT effect very close to that of 1% diclofenac (65.9%). Pharmacokinetic analysis was performed in plasma, liver and kidney and showed that the compounds present in CcI are not detected in vivo after a single-dose oral administration. In contrary, the metabolites, luteolin 7-O-glucuronide and luteolin 3’-O-sulfate, present at the highest bioavailability, are probably the main responsible for the anti-inflammatory activity previously reported. In conclusion, this work has developed a method to quantify the phenolic compounds contained in C. citratus; pointed the importance of harvesting and storing the plant material, in order to take the maximum advantages from the phenolic compounds use; and demonstrated, in safe doses, its anti-inflammatory activity, using an in vivo approach, which supports the traditional use of lemongrass infusion. Furthermore, C. citratus leaves flavonoids and tannins were highlighted as bioactive compounds, encouraging the development of new anti-inflammatory drugs or nutraceuticals.