Síntese e caracterização do poli(ácido láctico) para potencial uso em sistemas de liberação controlada de fármacos

With the advances in medicine, life expectancy of the world population has grown considerably in recent decades. Studies have been performed in order to maintain the quality of life through the development of new drugs and new surgical procedures. Biomaterials is an example of the researches to improve quality of life, and its use goes from the reconstruction of tissues and organs affected by diseases or other types of failure, to use in drug delivery system able to prolong the drug in the body and increase its bioavailability. Biopolymers are a class of biomaterials widely targeted by researchers since they have ideal properties for biomedical applications, such as high biocompatibility and biodegradability. Poly (lactic acid) (PLA) is a biopolymer used as a biomaterial and its monomer, lactic acid, is eliminated by the Krebs Cycle (citric acid cycle). It is possible to synthesize PLA through various synthesis routes, however, the direct polycondensation is cheaper due the use of few steps of polymerization. In this work we used experimental design (DOE) to produce PLAs with different molecular weight from the direct polycondensation of lactic acid, with characteristics suitable for use in drug delivery system (DDS). Through the experimental design it was noted that the time of esterification, in the direct polycondensation, is the most important stage to obtain a higher molecular weight. The Fourier Transform Infrared (FTIR) spectrograms obtained were equivalent to the PLAs available in the literature. Results of Differential Scanning Calorimetry (DSC) showed that all PLAs produced are semicrystalline with glass transition temperatures (Tgs) ranging between 36 - 48 °C, and melting temperatures (Tm) ranging from 117 to 130 °C. The PLAs molecular weight characterized from Size Exclusion Chromatography (SEC), varied from 1000 to 11,000 g/mol. PLAs obtained showed a fibrous morphology characterized by Scanning Electron Microscopy (SEM)

Síntese do Poli (ácido láctico) por policondensação direta utilizando um planejamento fatorial

The environmental impact caused by the disposal of non-biodegradable polymer packaging on the environment, as well as the high price and scarcity of oil, caused increase of searches in the area of biodegradable polymers from renewable resources were developed. The poly (lactic acid) (PLA) is a promising polymer in the market, with a large availability of raw material for the production of its monomer, as well as good processability. The aimed of this study was synthesis PLA by direct polycondesation of lactic acid, using the tool of experimental design (DOE) (central composite rotatable design (CCRD)) to optimize the conditions of synthesis. The polymer obtained was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), viscosimetric analysis, differential scanning calorimeter (DSC) and size exclusion chromatography (SEC). The results confirmed the formation of a poly (lactic acid) semicrystalline in the syntheses performed. Through the central composite rotatable design was possible to optimize the crystallization temperature (Tc) and crystallinity degree (Xc). The crystallization temperature maximum was found for percentage of catalyst around the central point (0,3 (%W)) and values of time ranging from the central point (6h) to the upper level (+1) (8h). The crystallization temperature maximum was found for the total synthesis time of 4h (-1) and percentage of catalyst 0,1(W%) (-1). The results of size exclusion chromatography (SEC) showed higher molecular weights to 0,3 (W%) percent of catalyst and total time synthesis of 3,2h

Síntese e caracterização de catalisadores de LaNiO3 não suportados e suportados em Al2O3 e ZrO2 para a reforma a vapor do metano

Ionic oxides with ABO3 structure, where A represents a rare earth element or an alkaline metal and B is a transition metal from group VIII of the periodic table are potential catalysts for oxidation and good candidates for steam reforming reaction. Different methods have been considered for the synthesis of the oxide materials with perovskite structure to produce a high homogeneous material with low amount of impurities and low calcination temperatures. In the current work, oxides with the LaNiO3 formula had been synthesized using the method of the polymeric precursors. The thermal treatment of the materials took place at 300 ºC for 2h. The material supported in alumina and/or zirconia was calcined at 800 ºC temperature for 4h. The samples had been characterized by the following techniques: thermogravimetry; infrared spectroscopy; X-ray diffraction; specific surface area; distribution of particle size; scanning electron microscopy and thermo-programmed reduction. The steam reforming reaction was carried out in a pilot plant using reducing atmosphere in the reactor with a mixture of 10% H2-Argon, a mass about 5g of catalyst, flowing at 50 mL.min-1. The temperature range used was 50 - 1000 oC with a heating rate of 10 oC.min-1. A thermal conductivity detector was used to analyze the gas after the water trapping, in order to permit to quantify the consumption of hydrogen for the lanthanum nickelates (LaNiO3). The results showed that lanthanum nickelate were more efficient when supported in alumina than when supported in zirconia. It was observed that the methane conversion was approximately 100% and the selectivity to hydrogen was about 70%. In all cases were verified low selectivity to CO and CO2

Novos monômeros obtidos a partir do metacrilato de glicidila, bisfenol A e 4, 4 isopropilidenodicicloexanol : síntese, caracterização estrutural e propriedades de compósitos para utilização em resinas de restauração dental

Nowadays, composite resins are the direct restorative materials more important in dental clinical performance, due to their versatility and aesthetic excellence. Bis-GMA (2,2-bis[4(2-hydroxy-3-metacryloxypropoxy)phenil]propane) is the base monomer more frequently used in restorative composite resins. However, this monomer presents some disadvantages, such as high viscosity and two aromatic rings in its structure that can promote allergic reactions to the humans. In this work, the main purpose was to synthesize new monomers from glycidyl methacrylate to use in dental restorative materials. Structural characterization of the monomers was carried out through FTIR and NMR 1H, and eight composites were produced from the new monomers, by addition of silane-treated alumino silicate particles (inorganic filler) and a photocuring system (camphorquinone and ethyl 4-dimethylaminebenzoate). The composites were analyzed by environmental scanning electronic microscopy and the water sorption and solubility, compressive strength and elastic modulus were determined. A commercial composite resin [Z100 (3M)] was used to comparison effect. The new composites presented general characteristics similar to the commercial ones; however, they didn t present the properties expected. This behavior was attributed to the lower degree of monomer reaction and to the granulometry and size distribution of the mineral filler in the polymeric matrix

Síntese enzimática de ésteres de açúcar: surfactantes e polímeros como novos materiais ambientalmente seguros

Sugar esters are substances which possess surfactant, antifungical and bactericidal actions and can be obtained through two renewable sources of raw materials: sugars and vegetable oils. Their excellent biodegradability, allied to lhe fact that they are non toxic, insipid, inodorous, biocompatible, no-ionic, digestible and because they can resist to adverse conditions of temperature, pH and salinity, explain lhe crescent use of these substances in several sections of lhe industry. The objective of this thesis was to synthesize and characterize surfactants and polymers containing sugar branched in their structures, through enzymatic transesterification of vinyl esters and sugars, using alkaline protease from Bacillus subtilis as catalyst, in organic medium (DMF).Three types of sugars were used: L-arabinose, D-glucose and sucrose and two types of vinyl esters: vinyl laurate and vinyl adipate. Aiming to reach high conversions from substrates to products for a possible future large scale industrial production, a serie of variables was optimized, through Design of Experiments (DOE), using Response Surface Methodology (RSM).The investigated variables were: (1) enzyme concentration; (2) molar reason of substrates; (3) water/solvent rale; (4) temperature and (5) time. We obtained six distinct sugar esters: 5-0-lauroyl L-arabinose, 6-0-lauroyl D-glucose, 1'-O-lauroyl sucrose, 5-0-vinyladipoyl L-arabinose, 6-0-vinyladipoyl D-glucose and 1 '-O-vinyladipoyl sucrose, being lhe last three polymerizable. The progress of lhe reaction was monitored by HPLC analysis, through lhe decrease of sugar concentration in comparison to lhe blank. Qualitative analysis by TLC confirmed lhe formation of lhe products. In lhe purification step, two methodologies were adopted: (1) chromatographic column and (2) extraction with hot acetone. The acylation position and lhe chemical structure were determined by 13C-RMN. The polymerization of lhe three vinyl sugar esters was possible, through chemical catalysis, using H2O2 and K2S2O8 as initiators, at 60°C, for 24 hours. IR spectra of lhe monomers and respective polymers were compared revealing lhe disappearance of lhe vinyl group in lhe polymer spectra. The molar weights of lhe polymers were determined by GPC and presented lhe following results: poly (5-0-vinyladipoyl L-arabinose): Mw = 7.2 X 104; PD = 2.48; poly (6-0-vinyladipoyl D-glucose): Mw = 2.7 X 103; PD = 1.75 and poly (1'-O-vinyladipoyl sucrose): Mw = 4.2 X 104; PD = 6.57. The six sugar esters were submitted to superficial tension tests for determination of the critical micelle concentrations (CMC), which varied from 122 to 167 ppm. Finally, a study of applicability of these sugar esters, as lubricants for completion fluids of petroleum wells was' accomplished through comparative analysis of lhe efficiency of these sugar esters, in relation to three commercial lubricants. The products synthesized in this thesis presented equivalent or superior action to lhe tested commercial products

Síntese, caracterização e aplicação de LaSBA-15 e como catalisador para obtenção de biodiesel de soja via rota etílica

Biodiesel is an alternative fuel, renewable, biodegradable and nontoxic. The transesterification of vegetable oils or animal fat with alcohol is most common form of production of this fuel. The procedure for production of biodiesel occurs most commonly through the transesterification reaction in which catalysts are used to accelerate and increase their income and may be basic, acid or enzyme. The use of homogeneous catalysis requires specific conditions and purification steps of the reaction products (alkyl ester and glycerol) and removal of the catalyst at the end of the reaction. As an alternative to improve the yield of the transesterification reaction, minimize the cost of production is that many studies are being conducted with the application of heterogeneous catalysis. The use of nano-structured materials as catalysts in the production of biodiesel is a biofuel alternative for a similar to mineral diesel. Although slower, can esterify transesterified triglycerides and free fatty acids and suffer little influence of water, which may be present in the raw material. This study aimed at the synthesis, characterization and application of nano-structured materials as catalysts in the transesterification reaction of soybean oil to produce biodiesel by ethylic route. The type material containing SBA-15 mesoporous lanthanum embedded within rightly Si / La = 50 was used catalyst. Solid samples were characterized by X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, nitrogen adsorption and desorption. For the transesterification process, we used a molar ratio of 20:1 alcohol and oil with 0.250 g of catalyst at 60°C and times of 6 hours of reaction. It was determined the content of ethyl esters by H-NMR analysis and gas chromatography. It was found that the variable of conversion obtained was 80%, showing a good catalytic activity LaSBA-15 in the transesterification of vegetable oils via ethylic route

Uso da glicerina oriunda da síntese do biodiesel em sistemas microemulsionados visando aplicação de herbicidas

The program PROBIODIESEL from the Ministry of Science and Technology has substantially increased glycerine, obtained as a sub-product of biodiesel production process, making it necessary to seek alternatives for the use of this co-product. On the other hand, herbicides although play a role of fundamental importance in the agricultural production system in force, have been under growing concern among the various segments of society because of their potential environmental risk. In this work, we used glycerin in microemulsion systems for application of herbicides, to improve efficiency and lower environmental pollution caused by the loss of those products to the environment. To obtain the systems of microemulsinados were used Unitol L90 NP and Renex 40 as surfactants, butanol as co-surfactant, coconut oil as oil phase and aqueous phase as we used solutions of glycerin + water. Through the determination of phase diagrams, the microemulsion region was found in the system E (L90 Unitol, coconut oil and glycerin + water 1:1). Three points were chosen to the aqueous phase rich in characterization and application in the solubilization of glyphosate and atrazine. Three experiments were performed in Horta, Department of Plant Sciences, Plant Science Sector, UFERSA, Mossoró-RN. The first experiment was conducted in randomized complete blocks with 20 treatments and four replications. The treatments consisted of five doses of the herbicide glyphosate (0.0, 0.45, 0.9, 1.35 and 1.8 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity of Brachiaria brizantha was measured at 7, 14, 28 and 60 DAA (days after application). At 60 DAA, we evaluated the biomass of plants. The second experiment was developed in randomized complete blocks with 20 treatments and four repetitions. The treatments consisted of five doses of the herbicide atrazine (0.0, 0.4, 0.8, 1.6 and 2.4 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity on Zea mays and Talinum paniculatum was evaluated at 2, 7, 20 DAA. The experiment III was developed in randomized complete blocks with 16 treatments and three repetitions. The treatments consisted of 16 combinations among the constituents of the microemulsion: Unitol L90 surfactant (0.0, 1.66, 5.0, 15 %) and glycerin (0.0, 4.44, 13.33 and 40.0 %). The phytotoxicity on Zea mays was evaluated at 1, 7 and 14 DAA. At 14 DAA, we evaluated the biomass of plants. The control plants using the microemulsions was lower than in the water due to the poisoning caused by the initial microemulsions in the leaves of the plants, a fact that hinders the absorption and translocation of the herbicide. There was no toxicity in Zea mays plants caused by the herbicide, however, were highly intoxicated by microemulsions. T. paniculatum was better controlled in spraying with the microemulsions, regardless of the dose of the herbicide. The glycerine did not cause plant damage. Higher poisoning the plants are caused by tensoactive Unitol L90 and higher rates occur with the use of higher concentrations of surfactant and glycerin, or microemulsion. The microemulsions used hampered the action of glyphosate in controlling B. brizantha and caused severe poisoning in corn, and these poisonings attributed mainly to the action of surfactant

Síntese e caracterização do líquido iônico tetrafluoroborato de 1-metil-3-(2,6-(S)-dimetiloct-2-eno)-imidazol como eletrólito para produção de hidrogênio via eletrólise da água

Ionic liquids (ILs) are organic compounds liquid at room temperature, good electrical conductors, with the potential to form as a means for electrolyte on electrolysis of water, in which the electrodes would not be subjected to such extreme conditions demanding chemistry [1]. This paper describes the synthesis, characterization and study of the feasibility of ionic liquid ionic liquid 1-methyl-3(2,6-(S)-dimethyloct-2-ene)-imidazole tetrafluoroborate (MDI-BF4) as electrolyte to produce hydrogen through electrolysis of water. The MDI-BF4 synthesized was characterized by thermal methods of analysis (Thermogravimetric Analysis - TG and Differential Scanning Calorimetry - DSC), mid-infrared spectroscopy with Fourier transform by method of attenuated total reflectance (FTIR-ATR), nuclear magnetic resonance spectroscopy of hydrogen (NMR 1H) and cyclic voltammetry (CV). Where thermal methods were used to calculate the yield of the synthesis of MDI-BF4 which was 88.84%, characterized infrared spectroscopy functional groups of the compound and the binding B-F 1053 cm-1; the NMR 1H analyzed and compared with literature data defines the structure of MDI-BF4 and the current density achieved by MDI-BF4 in the voltammogram shows that the LI can conduct electrical current indicating that the MDI-BF4 is a good electrolyte, and that their behavior does not change with the increasing concentration of water

Síntese e avaliação da atividade antitumoral de nanogéis de fucana A da alga marrom Spatoglossum schöederi (C. Agardh) Kützing

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Variabilidade espacial da textura de um latossolo vermelho eutroférrico sob cultivo de cana-de-açúcar

Estudos regionais mais detalhados, utilizando modelos de paisagem e geoestatística, têm demonstrado que, em áreas consideradas homogêneas, sob uma única classe de solo, existe dependência espacial de atributos granulométricos. Visando a avaliar a variabilidade espacial de atributos granulométricos em Latossolo Vermelho eutroférrico, foram feitas amostragens do solo em intervalos regulares de 50 m, em forma de malha, totalizando 306 pontos de amostragem. Foram coletadas amostras nas profundidades de 0-0,2 m e 0,6-0,8 m para a determinação da argila, silte, areia total (AT), areia grossa (AG), areia média (AM), areia fina (AF) e areia muito fina (AMF). Os dados foram submetidos à análise estatística descritiva, geoestatística e interpolação por krigagem. Os valores do coeficiente de variação apresentaram-se baixos para argila, médios para silte, AT, AF, AM e AMF e altos para AG. Observou-se ocorrência de dependência espacial para todas as variáveis com grau moderado de dependência espacial, com os maiores alcances ocorrendo na profundidade de 0-0,2 m. Os latossolos, apesar de serem homogêneos, mesmo em áreas de mesma classe de solo e manejo, apresentaram variabilidade diferenciada para os atributos granulométricos.

Soil organic matter as a function of nitrogen fertilization in crop successions

A interdependência dos ciclos de C e N reflete-se nos teores de matéria orgânica do solo (MOS). em um delineamento experimental em blocos casualizados, com parcelas sub-subdivididas, tendo como tratamento principal cinco doses de nitrogênio de cobertura na cultura do milho (0; 60; 120; 180 e 240 kg ha-1 de N), como tratamento secundário, as sucessões milho-milho e soja-milho, e como sub-subtratamento, duas profundidades de amostragem (0 a 0.2 e 0.2 a 0.4 cm), avaliaram-se os teores de MOS e de C orgânico nas frações solúvel em água (C-SA), ácidos húmicos (C-AH), ácidos fúlvicos (C-AF) e humina (C-H), por meio do método clássico de fracionamento químico, em um Latossolo Vermelho eutrófico, de textura argilosa. A adubação nitrogenada não afetou os teores de MOS, mas favoreceu a síntese de compostos da fração C-AH. Houve efeito quadrático das doses de N nos teores de C-SA e de C-AF na sucessão milho-milho. A sucessão soja-milho resultou em maiores teores de MOS e de C orgânico na fração humina.

Teores de proteína bruta para bovinos alimentados com feno de capim-tifton 85: parâmetros ruminais, eficiência de síntese microbiana e degradabilidade in situ

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cinética digestiva e eficiência de síntese de proteína microbiana em novilhos alimentados com farelo de girassol e diferentes fontes energéticas

Objetivou-se avaliar o efeito da substituição parcial do milho pela casca de soja e pelo farelo de gérmen de milho sobre a produção e eficiência de síntese de proteína microbiana e sobre as taxas de diluição e passagem ruminal. Foram utilizados três novilhos de corte, mestiços, canulados no rúmen e no duodeno, distribuídos em dois delineamentos em quadrado latino 3 x 3. As dietas experimentais, à base de silagem de milho (60%), apresentavam como fonte de proteína farelo de girassol e, como fonte de energia, milho (MI) ou sua substituição parcial pela casca de soja (CS) ou pelo farelo de gérmen de milho (FGM). Para o isolamento da massa microbiana, foram coletadas amostras de conteúdo ruminal às 3, 6, 9 e 12 horas após a alimentação. Utilizaram-se RNA como marcador microbiano e dicromato de sódio e Co-EDTA como indicadores das taxas de passagem e de diluição, respectivamente. A composição dos microrganismos ruminais não foi influenciada pelas dietas experimentais ou pelos horários de coleta. Não houve diferenças significativas no fluxo de matéria orgânica, carboidratos totais, nitrogênio e nitrogênio microbiano para o duodeno e na eficiência de síntese de proteína microbiana. As taxas de diluição foram semelhantes entre as dietas, com média de 13,4%/h. A taxa de passagem da silagem de milho mordentada foi menor, com tendência de menor taxa de passagem também para o farelo de girassol na dieta MI. A casca de soja e o farelo de gérmen de milho podem substituir parcialmente o milho, proporcionando ambiente ruminal adequado ao desenvolvimento da flora microbiana e conseqüente produção de proteína microbiana ruminal em novilhos confinados.

Eficiência de síntese microbiana e atividade enzimática em bovinos submetidos à suplementação com enzimas fibrolíticas

Avaliou-se o efeito da suplementação com enzimas fibrolíticas (celulase e xilanase) sobre a eficiência de síntese microbiana e a atividade enzimática da beta-1,4-endoglucanase (celulase) em animais consumindo dietas contendo silagem de milho e feno de tifton 85 (Cynodon spp.) como volumoso. Oito bovinos com fístulas no rúmen e no duodeno foram distribuídos em dois quadrados latinos 4 x 4, em esquema fatorial 2 x 2 (duas fontes de volumoso e adição ou não de enzimas). O complexo enzimático, proveniente de fonte comercial e extraído dos fungos Aspergillus niger e Trichoderma longibrachiatum, foi fornecido misturado à ração total na proporção de 12 g/animal/dia. A adição de enzimas às dietas contendo silagem de milho e feno de tifton 85 aumentou a atividade da beta-1,4-endoglucanase no fluido ruminal. Não houve efeito das enzimas sobre a eficiência de síntese de proteína microbiana, o fluxo de nitrogênio microbiano (N-mic) e nitrogênio não-amoniacal (NNA), com valores médios de 31,8 e 33,9 g de N/kg de MODR; 0,40 e 0,41 g de N/Mcal de EDR; 78,2 e 52,5 g/dia; 89,6 e 76,3 g/dia, respectivamente, para as dietas contendo silagem de milho e feno de tifton. A adição de enzimas fibrolíticas não influenciou os parâmetros ruminais de bovinos alimentados com feno e silagem de milho.

Análise e classificação de imagens de lesões da pele por atributos de cor, forma e textura utilizando máquina de vetor de suporte

The skin cancer is the most common of all cancers and the increase of its incidence must, in part, caused by the behavior of the people in relation to the exposition to the sun. In Brazil, the non-melanoma skin cancer is the most incident in the majority of the regions. The dermatoscopy and videodermatoscopy are the main types of examinations for the diagnosis of dermatological illnesses of the skin. The field that involves the use of computational tools to help or follow medical diagnosis in dermatological injuries is seen as very recent. Some methods had been proposed for automatic classification of pathology of the skin using images. The present work has the objective to present a new intelligent methodology for analysis and classification of skin cancer images, based on the techniques of digital processing of images for extraction of color characteristics, forms and texture, using Wavelet Packet Transform (WPT) and learning techniques called Support Vector Machine (SVM). The Wavelet Packet Transform is applied for extraction of texture characteristics in the images. The WPT consists of a set of base functions that represents the image in different bands of frequency, each one with distinct resolutions corresponding to each scale. Moreover, the characteristics of color of the injury are also computed that are dependants of a visual context, influenced for the existing colors in its surround, and the attributes of form through the Fourier describers. The Support Vector Machine is used for the classification task, which is based on the minimization principles of the structural risk, coming from the statistical learning theory. The SVM has the objective to construct optimum hyperplanes that represent the separation between classes. The generated hyperplane is determined by a subset of the classes, called support vectors. For the used database in this work, the results had revealed a good performance getting a global rightness of 92,73% for melanoma, and 86% for non-melanoma and benign injuries. The extracted describers and the SVM classifier became a method capable to recognize and to classify the analyzed skin injuries