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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.
121

Extração, determinação da composição fenólica e avaliação do potencial de desativação de espécies reativas de oxigênio e da atividade anti-inflamatória de resíduos de amendoim, pimenta-rosa e pimenta-do-reino / Extraction, determine the phenolic composition and assessment of the potential deactivation of reactive oxygen species and anti-inflammatory activity of residue peanut skin, pink pepper and black pepper

Keityane Boone Bergamaschi 19 April 2016 (has links)
O setor agroindustrial tem se expandido muito nos últimos anos, levando o país a um aumento na geração de resíduos agroindustriais, sendo que a maior parte deles ainda é descartada no meio ambiente, sem tratamento adequado, ou utilizada na alimentação animal, destinos que a priori, não geram ganhos econômicos para a agroindústria além de representarem gargalos logísticos e ambientais na sua disposição. Nesse sentido, o presente trabalho teve como objetivos otimizar o processo de extração de compostos bioativos, avaliar in vitro as atividades antioxidante, por meio da desativação de espécies reativas de oxigênio, e anti-inflamatória, bem como determinar a composição fenólica dos resíduos agroindustriais a saber: película de amendoim (Arachis hypogaea) (cultivares IAC886 e IAC505), pimenta-rosa (Schinus terebinthifolius Raddi) e pimenta-do-reino (Piper Nigrum L). O processo de otimização da extração de compostos antioxidantes foi realizado utilizando dois processos de extração, extração convencional e subcrítica, em delineamento composto central rotacional, utilizando como variáveis a temperatura e tempo e a pressão e temperatura, respectivamente, com os solventes etanol 80%, água e propilenoglicol 80%. Durante o processo de otimização a atividade antioxidante foi avaliada pelo método de sequestro do radical ABTS. Os melhores resultados foram obtidos para a extração convencional com os solventes etanol 80%, água e propilenoglicol 80%. A película de amendoim (IAC505) apresentou as maiores atividades antioxidantes (1.396,67, 580,44 e 859,89 μmol.g-1 em equivalentes de trolox, para os solventes etanol 80%, água e propilenoglicol 80%, respectivamente). A partir dos resultados obtidos para os solventes testados, utilizando a extração convencional, foram feitas outras análises de atividade antioxidante considerando o tempo e temperatura ideal de extração. Foram realizadas análises de avaliação da capacidade de redução de Folin-Ciocalteau e potencial de desativação dos radicais livres sintéticos (DPPH e ABTS) e espécies reativas de oxigênio (radicais peroxila, superóxido e ácido hipocloroso). O solvente de extração que apresentou melhores resultados em todos os ensaios foi o etanol 80%, sendo, portanto o solvente utilizado nas análises subsequentes. A partir da definição do melhor sistema extrator foram realizadas análises da composição fenólica, por meio das técnicas de cromatografia líquida de alta eficiência em modo analítico (HPLC-RP), cromatografia gasosa acoplada com espectrometria de massas (GC-MS), e avaliação in vitro da atividade anti-inflamatória. Foram identificados nos resíduos estudados procianidinas B1 e B2, ácido p-cumárico, miricetina, ácido ferúlico, ácido siríngico, ácido sinápico, epicatequina e catequina. A pimenta-do-reino diminui significativamente os níveis de TNF-α e nitritos, reduzindo assim o processo inflamatório gerado. Os resultados obtidos neste trabalho demonstram que estes resíduos agroindústrias possuem grande potencial biológico, podendo assim ser melhores aproveitados tanto pela indústria de alimentos quanto pela indústria farmacêutica. / The agribusiness sector has expanded greatly in recent years, leading the country to an increase in the generation of agro-industrial residues, even though most of them are still discarded in the environment without proper treatment, or used in animal feed, destinations that a priori do not generate economic gains for agribusiness besides representing logistical and environmental bottlenecks at your disposal. In this sense, the present study aimed to optimize the bioactive compounds extraction process, to evaluate in vitro the antioxidant activities, through the deactivation of reactive oxygen species, and anti-inflammatory as well as determine the phenolic composition of agro-industrial residues namely peanut skin (Arachis hypogaea) (IAC886 and IAC505 cultivars), pink pepper (Schinus terebinthifolius Raddi) and black pepper (Piper nigrum L). The optimization process of extraction of antioxidants was performed using two extraction processes, conventional extraction and subcritical on central composite design, using as variable temperature and time and the pressure and temperature, respectively, with solvents ethanol 80%, water and propyleneglycol 80%. During the optimization process the antioxidant activity was evaluated for the kidnapping method of ABTS radical. The best results were obtained for the conventional extraction with solvents ethanol 80%, water and propyleneglycol 80%. Peanut skin (IAC505) showed the highest antioxidant activity (1,396.67, 580.44 and 859.89 μmol.g-1 in Trolox equivalents, for solvents ethanol 80%, water and propyleneglycol 80%, respectively). From the results obtained for the solvents tested, using conventional extraction, other analyzes were done considering the antioxidant activity optimum time and temperature of extraction. Valuation analyzes were carried out of the Folin-Ciocalteau reduction capability and potential disabling of synthetic free radical (DPPH and ABTS) and reactive oxygen species (peroxyl radicals, superoxide and hypochlorous acid). The extraction solvent that showed better results in all tests was ethanol 80%, and therefore the solvent used in subsequent analyzes. From the definition of the best extraction system analyzes were made of phenolic composition by means of liquid chromatography techniques of high efficiency in analytic way (HPLC-RP), gas chromatography coupled with mass spectrometry (GC-MS), and reviewed in vitro anti-inflammatory activity. They were identified at residues studied procyanidins B1 and B2, p-coumaric acid, myricetin, ferulic acid, syringic acid, sinapic acid, epicatechin, and catechin. The black pepper significantly reduces TNF-α and nitrite levels, thereby reducing the inflammatory process generated. The results of this study demonstrate that these agribusinesses waste have great biological potential, and thus can be best availed by both the food industry and the pharmaceutical industry.
122

Mixture Design Response Surface Methodology Analysis of Seven Natural Bioactive Compounds to Treat Prostate Cancer

Berlin, Ian Geddes 15 December 2021 (has links)
Natural bioactive compounds have drawn the interest of many researchers worldwide in their effort to find novel treatments, including prostate cancer (PC) treatment which is estimated to be 13.1% of all new cancer cases in the U.S. in 2021. Many of these bioactive compounds have been identified from treatments in traditional Chinese medicine (TCM), that often have multiple bioactive compounds present. However, in vitro studies frequently focus on the compounds in isolation, or in simple combinations of two compounds. We used mixture design response surface methodology (MDRSM) to assess changes in PC cell viability after 48 hours of treatment to identify the optimal mixture of all 35 three-compound combinations of seven bioactive compounds from TCM. We used Berberine, Wogonin, Shikonin, Curcumin, Triptolide, Emodin, and Silybin to treat PC-3, DU145, and LNCaP human PC cells, and a drug-resistant PC-3 cell line. Berberine and Wogonin most frequently contributed to the optimal combination to reduce cell viability in PC-3 and LNCaP cells; DU145 cells more frequently responded best to a single compound.
123

[en] DESIGN OF EXPERIMENTS FOR OPTIMIZING ACCEPTANCE CRITERIA OF MEASURING INSTRUMENTS CALIBRATION / [pt] PLANEJAMENTO DE EXPERIMENTOS PARA OTIMIZAÇÃO DE CRITÉRIOS DE ACEITAÇÃO DA CALIBRAÇÃO DE INSTRUMENTOS DE MEDIÇÃO

MATHEUS JOSÉ PINHEIRO GUERRA 15 July 2016 (has links)
[pt] O objetivo desta dissertação é propor critérios de aceitação da calibração individual de transmissores secundários de pressão estática, pressão diferencial e temperatura como dados de entrada da calibração final do sistema de medição de vazão de gás natural por placa de orifício. A motivação que norteou o desenvolvimento deste trabalho resultou do fato de o recém-introduzido Regulamento Técnico de Medição de Petróleo e Gás Natural (RTM) não definir as tolerâncias aplicáveis aos instrumentos associados a este tipo de sistema de medição, deixando esta decisão a cargo do usuário. Nesse sentido, o trabalho visa contribuir para a melhoria do controle metrológico do medidor de vazão por placa de orifício vis-à-vis o que determina o RTM, i.e.: incerteza expandida limitada a 1,5 porcento em medições fiscais e 2 porcento em medições de apropriação. A metodologia utilizada é a do planejamento experimental e de superfície de resposta, que permitiu otimizar os critérios de aceitação da incerteza associada a cada um dos três instrumentos que interferem no sistema de medição. Os resultados obtidos definem valores critérios-limites para a calibração de cada um dos transmissores secundários, de pressão estática, pressão diferencial e temperatura. Dentre as conclusões destaca-se a validação da metodologia proposta, que permitiu definir os critérios de aceitação da calibração pela análise da calibração individual de cada instrumento que integra o sistema global do medidor por placa de orifício. Finalizando, o trabalho encaminha recomendações para a melhoria da estrutura laboratorial da Unidade Operacional da Petrobras, no Espírito Santo (UO-ES), visando assegurar atendimento aos requisitos do regulamento técnico de medição de petróleo e gás natural. / [en] The aim of this dissertation is to propose individual acceptance criteria calibration of secondary transmitters of static pressure, differential pressure and temperature as the final calibration input data of the natural gas flow measurement system by orifice plate. The motivation that guided the development of this work resulted from the fact that the newly introduced technical regulation of Petroleum and Natural Gas measurement (RTM) does not define the applicable tolerances to associated instruments with this type of measurement system, leaving this decision in charge of user. In this sense, the work aims to contribute to the improvement of the metrological control of the flowmeter by orifice plate vis-à-vis what determines the RTM, e.g.: expanded uncertainty limited to 1.5 percent on fiscal measurements and 2 percent on measurements appropriation. The methodology used is the experimental design and response surface witch allowed to optimize the acceptance criteria of uncertainty associated each of the three instruments that interfere in the measurement system. The obtained results define the limits criteria values for each calibration of secondary transmitters, static pressure, differential pressure and temperature. Among the conclusions stands out the validation of proposal methodology, which allowed to define the acceptance criteria of calibration for analysis of individual calibration of each instrument that integrates global system for measuring orifice plate. Finally, the work forward recommendations for the improvement of laboratory structure of Petrobras Operation, in the Espírito Santo (UO-ES) in order to ensure compliance with the requirements of the technical regulation of oil and natural gas measurement.
124

Activation of the carbonaceous material from the pyrolysis of waste tires for wastewater treatment.

Malise, Lucky 07 1900 (has links)
M.Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / The generation of waste tires is one of the most serious environmental problems in the modern world due to the increased use of auto mobiles all over the world. Currently there is a problem with the disposal of waste tires generated since there are strict regulations concerning their disposal through landfill sites. Therefore, there is a need to find ways of disposing these waste tires which pose serious health and environmental problem. The pyrolysis of the waste tires has been recognised as the most promising method to dispose the waste tires because it can reduce the weight of the waste tires to 10% of its original weight and produce products such as pyrolysis oil, pyrolysis char, and pyrolysis char. These products can be further processed to produce value added products. The char produced from the pyrolysis of waste tires can be further activated to produce activated carbon. This study is based on the chemical activation of waste tire pyrolysis char to produce activated carbon for the removal of lead ions from aqueous solution. This was done by impregnating the waste tire pyrolysis char with Potassium hydroxide and activating it inside a tube furnace under inert conditions to produce waste tire activated carbon. Adsorbent characterisation techniques (SEM, FTIR, TGA, XRF, XRD, BET, and Proximate analysis) were performed on the waste tire pyrolysis char and the activated carbon produced to make a comparison between the two samples. The results showed that the waste tire activated carbon produced has better physical and chemical properties compared to the raw waste tire pyrolysis char. Adsorption results revealed that waste tire activated carbon achieves higher removal percentages of lead ions from aqueous solution compared to waste tire pyrolysis char. The results also showed the effect of various process variables on the adsorption process. Adsorption isotherms, kinetics, and thermodynamics were also studied. The adsorption of lead ions agreed with the Freundlich isotherm model for both the waste tire pyrolysis char and waste tire activated carbon. In terms of adsorption kinetics, the experimental data provided best fits for the pseudo-first order kinetic model for both the waste tire pyrolysis char and the waste tire activated carbon. The adsorption thermodynamics study revealed that the process is an exothermic process and spontaneous in nature. Response surface methodology was used to determine the combined effect of process variables on the adsorption of lead ions onto waste tire activated carbon and to optimise the process using numerical optimisation. The optimum conditions were found to be adsorbent dosage = 1g/100ml, pH = 7, contact time = 115.2 min, initial meta concentration = 100 mg/l, and temperature = 25°C to achieve a maximum adsorption capacity of 93.176 mg/l.
125

Optimizing the Extraction of Phenolic Antioxidant Compounds from Peanut Skins

Ballard, Tameshia Shaunt'a 29 July 2008 (has links)
Peanut skins are a low-value byproduct of peanut blanching operations. They have been shown to contain significant levels of phenolic compounds with demonstrated antioxidant properties. The effects of two types of extraction methods: solid-liquid extraction (SLE) and microwave-assisted extraction (MAE) on the recovery of phenolic compounds from peanut skins were investigated. Response surface methodology was used to optimize extraction conditions based on total phenolic content (TPC), ORAC (oxygen radical absorbance capacity) activity and <i>trans</i>-resveratrol content. The protective effect of peanut skin extracts (PSE) against hydrogen peroxide (H₂O₂)-induced oxidative stress in human brain microvascular endothelial cells (HBMEC) and the effect of PSE on lipid oxidation in commercial peanut butter were also evaluated. In the SLE method, EtOH was found to be the most efficient extraction solvent followed by MeOH, water and EA. Despite EtOH extracts having a higher TPC, samples extracted with MeOH demonstrated slightly higher ORAC activity. Resveratrol was identified in MeOH extracts but was not found in EtOH, water or EA extracts. In the MAE procedure, the maximum predicted TPC under the optimized conditions was 144 mg phenols/g skins compared to 118 mg/g with SLE. The maximum predicted ORAC activity was 2789 μmol TE/g as opposed to 2149 μmol TE/g with the SLE method. MAE was able to extract more phenolic compounds (with higher antioxidant activity) in a faster time than the SLE procedure. In addition, resveratrol was identified in PSE derived from MAE although at relatively low levels. PSE were found to have some protective effects against oxidative stress in HBMEC. Higher doses of PSE appeared to have a slightly cytotoxic effect. However, the data were highly variable which made it difficult to arrive at any definitive conclusions regarding the potential benefits of PSE in preventing oxidative damage to cells. In the PB experiment, hexanal levels over the storage period were not high enough for the samples to be considered oxidized. However, hexanal values of PB samples treated with PSE were lower than the control throughout storage, which suggests that PSE may provide some protection against oxidation of PB. / Ph. D.
126

Application of Mixture Design Response Surface Methodology for Combination Chemotherapy in PC-3 Human Prostate Cancer Cells

Oblad, Richard Vernon 01 April 2018 (has links)
Combining chemotherapeutics to treat malignant tumors has been shown to be effectivein preventing drug resistance, tumor recurrence, and reducing tumor size. We modeledcombination drug therapy in PC-3 human prostate cancer cells using mixture design responsesurface methodology (MDRSM), a statistical technique designed to optimize compositions thatwe applied in a novel manner to design combinations of chemotherapeutics. Conventionalchemotherapeutics (mitoxantrone, cabazitaxel, and docetaxel) and natural bioactive compounds(resveratrol, piperlongumine, and flavopiridol) were used in twelve different combinationscontaining three drugs at varying concentrations. Cell viability and cell cycle data werecollected and used to plot response surfaces in MDRSM that identified the most effectiveconcentrations of each drug in combination. MDRSM allows for extrapolation of data fromthree or more compounds in variable ratio combinations, unlike the Chou-Talalay method.MDRSM combinations were compared with combination index data from the Chou-Talalaymethod and were found to coincide. We propose MDRSM as an effective tool in devisingcombination treatments that can improve treatment effectiveness, and increase treatmentpersonalization because MDRSM measures effectiveness rather than synergism, potentiation orantagonism.
127

Highly Efficient One-Step Protein Immobilization on Polymer Membranes Supported by Response Surface Methodology

Schmidt, Martin, Abdul Latif, Amira, Prager, Andrea, Gläser, Roger, Schulze, Agnes 03 April 2023 (has links)
Immobilization of proteins by covalent coupling to polymeric materials offers numerous excellent advantages for various applications, however, it is usually limited by coupling strategies, which are often too expensive or complex. In this study, an electron-beambased process for covalent coupling of the model protein bovine serum albumin (BSA) onto polyvinylidene fluoride (PVDF) flat sheet membranes was investigated. Immobilization can be performed in a clean, fast, and continuous mode of operation without any additional chemicals involved. Using the Design of Experiments (DoE) approach, nine process factors were investigated for their influence on graft yield and homogeneity. The parameters could be reduced to only four highly significant factors: BSA concentration, impregnation method, impregnation time, and electron beam irradiation dose. Subsequently, optimization of the process was performed using the Response Surface Methodology (RSM). A one-step method was developed, resulting in a high BSA grafting yield of 955 mgm−2 and a relative standard deviation of 3.6%. High efficiency was demonstrated by reusing the impregnation solution five times consecutively without reducing the final BSA grafting yield. Comprehensive characterization was conducted by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and measurements of zeta potential, contact angle and surface free energy, as well as filtration performance. In addition, mechanical properties and morphology were examined using mercury porosimetry, tensile testing, and scanning electron microscopy (SEM).
128

Development and Optimization of Dextromethorphan HBr-2-Hydroxy Propyl ß-Cyclodextrin Inclusion Complex Based Orally Disintegrating Tablets Using Response Surface Methodology

Adhikari, Saugat January 2016 (has links)
No description available.
129

Mise au point des espèces du genre Stephania au Cambodge : études systématique, phytochimique et pharmacologique / Update on the species of the genus Stephania in Cambodia : systematic, phytochemical and pharmacological studies

Dary, Chhavarath 18 July 2016 (has links)
L’objectif de la thèse est une mise au point des espèces de Stephania répertoriées au Cambodge par l’étude systématique, phytochimique et pharmacologique. Du point de vue systématique, les travaux ont permis de répertorier sept espèces et deux variétés de Stephania au Cambodge : S. cambodica, S. japonica var. discolor et var. timoriensis, S. oblata, S. pierrei, S. rotunda (espèce-type), S. suberosa, et S. venosa. La clef de détermination établie lors de ce travail de thèse permet d’identifier ces espèces. D’après les résultats phylogénétiques, seul S. pierrei est monophylétique, ce qui représente moins de 10% des espèces de Stephania. L’étude chimique de cinq espèces a été réalisée par des méthodes chromatographiques (CLHP, UCLHP) et des méthodes spectroscopiques. Différents alcaloïdes ont été proposés comme marqueurs : la palmatine, la roémérine et la tétrahydropalmatine pour S. cambodica et S. rotunda, la cépharanthine, la tétrahydropalmatine et la xylopinine pour S. suberosa, la cépharanthine pour S. pierrei, la crébanine, et la tétrahydropalmatine pour S. venosa. Neuf alcaloïdes ont été isolés à partir du tubercule de S. cambodica, dont un nouveau composé dénommé «angkorwatine ». Une méthode d’éco-extraction des alcaloïdes assistée par ultrasons a été mise au point et optimisée par un plan d’expérience pour cette espèce. Une méthode analytique par UCLHP a été développée et validée pour le contrôle qualité de S. cambodica. Les résultats montrent que les extraits hydroéthanoliques obtenus par macération à partir du tubercule de S. suberosa, S. venosa et S. rotunda présentent une activité anti-inflammatoire importante (in vitro) avec un ratio anti-inflammatoire élevé. / The thesis aims to provide update on species of the genus Stephania recorded in Cambodia by systematic, phytochemical and pharmacological studies.The systematic study allowed to list seven species and two varieties of Stephania in Cambodia: S. cambodica, S. japonica var. discolor and var. timoriensis, S. oblata, S. pierrei, S. rotunda (type species), S. suberosa and S. venosa. The presence of S. japonica var. timoriensis and S. oblata is reported for the first time in Cambodia. According to the phylogenetic results, only S. pierrei is monophyletic, which represents less than 10% of species in the genus Stephania. Chemical studies on the tubers of five species were carried out using chromatographic methods (HPLC, UHPLC) and spectroscopic methods. Different isolated alkaloids have been proposed as markers: palmatine, roemerine and tetrahydropalmatine for S. cambodica and S. rotunda, cepharanthine, tetrahydropalmatine, and xylopinine for S. suberosa, cepharanthine for S. pierrei, crebanine, and tetrahydropalmatine for S. venosa. Nine alkaloids belonging to five classes were isolated from the tuber of S. cambodica and a new compound namely "angkorwatine" was described. Ultrasound assisted extraction of alkaloids was developed and optimized by Design of Experiment for this species. This innovative extraction is a good alternative to conventional methods. An analytical UHPLC method was developed and validated for the quality control of S. cambodica. Results show that hydroethanolic extracts obtained by maceration of S. suberosa, S. rotunda and S. venosa exhibit significant anti-inflammatory activity with high anti-inflammatory ratio (selectivity index).
130

Avaliação da produção de etanol em temperaturas elevadas por uma linhagem de S. cerevisiae. / Evaluation of ethanol production at high temperatures by a strain of S. cerevisiae.

Souza, Crisla Serra 24 April 2009 (has links)
A metodologia de superfície de resposta foi utilizada para otimizar as condições e obter maiores produção de etanol e viabilidade para a linhagem de S. cerevisiae 63M em processo descontínuo, resultando nas condições: 200 g.L-1 de sacarose, 40 g.L-1 de inóculo a 30 °C. Diferentes tipos de processos foram comparados e o processo que apresentou maiores viabilidade, produtividade e rendimento foi o descontínuo alimentado por pulsos de volumes decrescentes de sacarose a 30 °C. A redução da concentração de sacarose foi uma estratégia que permitiu aumentar a temperatura até 37 °C sem perdas em viabilidades. Uma linhagem utilizada nas destilarias brasileiras foi comparada com a linhagem 63M em temperaturas elevadas e observou-se que a 63M produziu maior produtividade e rendimento. Oito ciclos sucessivos de fermentação com reutilização de células da linhagem 63M foram realizados em meio sintético em processo descontínuo alimentado por pulsos de sacarose a 37 °C e uma perda gradual de viabilidade foi observada, mas o etanol final permaneceu constante nos oitos ciclos. / Surface response methodology was used to optimize the conditions and to obtain higher ethanol production and viability to strain 63M of S. cerevisiae in batch culture, resulting in the conditions: 200 g.L-1 sucrose, 40 g.L-1 inoculum at 30 °C. Different types of processes were compared and the process that presented higher viability, productivity and yield was pulse fed-batch using five decreasing pulses of sucrose at 30 °C. The reduction of the sucrose concentration was a strategy that allowed increasing the temperature up to 37 °C without losses in viabilities. An industrial strain used in Brazilian distilleries was compared with strain 63M at high temperatures and it was observed that strain 63M produced higher productivity and yield. Eight successive cycles of fermentation with reuse of cells of strain 63M were carried out in synthetic medium in fed-batch process using sucrose pulses at 37 °C and a gradual loss of viability was observed, but the final ethanol was kept constant in the eight fermentation cycles.

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