TiO2 derivatives with distinct morphologies have been successfully obtained by microwave assisted hydrothermal synthesis in acidic and alkaline medium using mild conditions. Titanium tetraisopropoxide (TTIP) was used as precursor in different environmental conditions under low temperatures, inferior to 150 °C, and short synthesis times, from 2 to 60 min. X ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption at 77 K (BET) were used to characterize the microstructural properties of the oxides. In the acidic synthesis the reaction time and temperature are not accompanied by significant changes in the structure of the material. However, in the basic conditions, the concentration of Na+ ions strongly influences the particle morphology and growth. The morphology of the nanoparticles shows irregular spheres in acidic conditions, while in alkaline medium, needle like structures are formed as well as aggregated nanotube-like structures synthesized in only 30 min. Besides the difference in the morphology and structure, in both systems, high surface area was obtained.

RESUMO O látex de mangabeira, planta nativa do cerrado, apresenta potencial biotecnológico para desenvolvimento de novos fármacos. Pouco se sabe sobre os métodos de coleta e produtividade de látex em mangabeira, a qual vem sendo explorada comercialmente para produção de frutos de modo principalmente extrativista. Buscando informações sobre a utilização do látex de mangabeira foi avaliada, nesse trabalho, a produtividade do látex associada aos métodos de sangria; às condições ambientais; às características sazonais e anatômicas dessa espécie. Como resultado observou-se que o método de coleta utilizado comumente em seringueira não é apropriado para mangabeira, sendo a sangria feita com facão na região do caule o método mais produtivo. Em relação à anatomia da casca, a espessura, a posição e o número de vasos lactíferos influenciam na produção. Resultados também mostraram que a casca de mangabeira é espessa e que o número de vasos lactíferos é superior na região interna, evidenciando que sangrias utilizando cortes superficiais não são eficientes, pois não atingem os vasos lactíferos. Também, foi observado que o aumento da temperatura ambiental tem influência positiva na produtividade do látex e que na época da frutificação a produção de látex é significativamente inferior. Isso provavelmente ocorre porque a planta utiliza uma parcela dos seus metabólitos secundários para formação do fruto, gerando uma menor disponibilidade desses metabólitos para a produção de látex.

ABSTRACT The mangabeira latex, plant native from Cerrado, shows biotechnological potential for the development of new drugs. Little is known about the latex productivity and bleeding methods in mangabeira, which is usually utilized in extractive way for fruit production. Aiming to broaden the knowledge about mangabeira latex production it was evaluated the productivity associated with bleeding methods; environmental conditions; anatomical aspects from the bark and seasonal properties. As results it was observed that the bleeding method commonly used in rubber tree is not appropriated to mangabeira; the most productive bleeding method was using a knife in stalk region. The bark thickness and lactiferous vessels number are associated with latex production. Anatomical analysis showed that the bark in mangabeira is thick and the lactiferous vessels are deeply localized, in this way some superficial bleeding methods are not able to reach the vessels. It was also observed that the increase in environmental temperature has a positive influence on the productivity of latex and that during the fruiting time the latex production is significantly lower. This probably occurs because the plant uses part of the secondary metabolites for fruit formation, which reduced the availability of these metabolites to latex production.

The performance of advanced electronic ceramics is directly related to the synthesis route employed. Sol-gel methods are widely used for this purpose. However, the physicochemical intermediate steps are still not well understood. Better understanding and control of these processes can improve the final quality of samples. In this work, we studied theoretically the formation of metal complexes between citric acid and lithium or barium metal cations with different citric acid/metal proportions, using Density Functional Theory electronic structure calculations. Infrared and Raman scattering spectra were simulated for the more stable geometric configurations. Using this methodology, we identified some features of complexes formed in the synthesis process. Our results show that the complexes can be distinguished by changes in the bands assigned to C=O, COH-, and COO- group vibrations. An estimate of the most stable complexes is made based on total energy.

Nitric oxide (NO) is a diffusible messenger that has been involved in numerous physiological processes ranging from vasodilatation and antimicrobial properties to wound healing. The beneficial effects can be attributed to the role NO plays in angiogenesis, inflammation and tissue remodeling. In the present work, a polymeric device for the sustained site specific delivery of nitric oxide using a latex rubber matrix from Hevea brasiliensis which encapsulates the spin trap iron(II)- diethyldithiocarbamate complex (FeDETC) was developed. The release profiles of NO from latex rubber matrix were studied and stability studies were carried out. Electron Paramagnetic Resonance (EPR) signal of NO was detected in the membrane exposed to ambient atmosphere at room temperature (25 °C) even after 350 hours. FTIR spectroscopy data indicated that NO-FeDETC retained its structural and spectroscopic properties upon encapsulation in the latex matrix. The NO delivery system developed in this work as a membrane, presented high stability.

Natural Rubber Latex (NRL) can be used successfully in controlled release drug delivery due to their excellent matrix forming properties. Recently, NRL has shown to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. A dermatological delivery system comprising a topically acceptable, inert support impregnated with a metronidazole (MET) solution was developed. MET 2-(2- methyl- 5-nitro- 1H- imidazol- 1-yl) ethanol, has been widely used for the treatment of protozoa and anaerobic bacterial infections. MET is a nitroimidazole anti-infective medication used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. In a previous study, we have tested NRL as an occlusive membrane for GBR with promising results. One possible way to decrease the inflammatory process, it was incorporated the MET in NRL. MET was incorporated into the NRL, by mixing it in solution for in vitro protein delivery experiments. The solutions of latex and MET were polymerized at different temperatures, from -100 to 40 °C, in order to control the membrane morphology. SEM microscopy analysis showed that the number, size and distribution of pores in NRL membranes varied depending on polymerization temperature, as well as its overall morphology. Results demonstrated that the best drug-delivery system was the membrane polymerized at -100 °C, which does release 77,1% of its MET content for up 310 hours.

In this work, we propose natural rubber latex (NRL) membranes as a protein delivery system. For this purpose Bovine Serum Albumin (BSA) was incorporated into the latex solution for in vitro protein delivery experiments. Different polymerization temperatures were used, from -10 to 27 °C, in order to control the membrane morphology. These membranes were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), as well as the Lowry Method to measure the BSA release. SEM and AFM microscopy analysis showed that the number, size and distribution of pores in NRL membranes can be varied, as well as its overall morphology. We have found that the morphology of the membrane is the predominant factor for higher protein release, compared with pore size and number of pores. Results demonstrated that the best drug-delivery system was the membrane polymerized at RT (27 °C), which does release 66% of its BSA content for up to 18 days. Our results indicate that NRLb could be used in the future as an active membrane that could accelerate bone healing in GBR.