Curcumin, the main bioactive polyphenolic compound in Curcuma longa L. rhizomes has a wide range of bioactive properties. Curcumin presents low solubility in water and thus limited bioavailability, which decreases its applicability. In this study, cytotoxic effects of curcumin solid dispersions (CurSD) were evaluated against tumor (breast adenocarcinoma and lung, cervical and hepatocellular carcinoma) and non-tumor (PLP2) cells, while cytotoxic and genotoxic effects were evaluated in Allium cepa. The effect of the CurSD on the acetylcholinesterase (AChE), butyrylcholinesterase (BChE), glutathione S-transferase (GST), and monoamine oxidase (MAO A-B) enzymes was determined, as well as its capacity to inhibit the oxidative hemolysis (OxHLIA) and the formation of thiobarbituric acid reactive substances (TBARS). CurSD are constituted by nanoparticles that are readily dispersible in water, and inhibited 24% and 64% of the AChE and BChE activity at 100 μM, respectively. GST activity was inhibited at 30 μM while MAO-A and B activity were inhibited at 100 μM. CurSD showed cytotoxicity against all the tested tumor cell lines without toxic effects for non-tumor cells. No cytotoxic and genotoxic potential was detected with the Allium cepa test. CurSD maintained the characteristics of free curcumin on the in vitro modulation of important enzymes without appreciable toxicity.

Many synthesis methods are available to obtain a set of specific characteristics for lead zirconate titanate (PZT) piezoelectric ceramic powders. In this work, we have successfully prepared PZT powder samples through the Polymeric Precursor Method with x = 0.6, according the general formula Pb (ZrxTi1-x)O3. The powders were thermally treated from 380 to 550 oC and characterized by Raman spectroscopy and X-ray diffraction (DRX) in order to evaluate the effects of thermal treatment on the phase formation and the crystallization processes. The results obtained by Raman spectroscopy were compared to refined crystal data obtained by Rietveld method, leading to coherent conclusions about the structural effects occurring along the temperature of calcination. It was possible to characterize the tetragonal perovskite phase as predominant phase occurs only after 500 oC, but its crystallinity is already determined by synthesis method. Thus, no ordering process is verified for perovskite as a function of the temperature increasing during thermal treatment, in spite of the continuous pyrochlore-to-perovskite phase transition. The pyrochlore secondary phase starts to vanish before its proper crystallization process, changing the tetragonality of previously formed perovskite phase.

Nickel-silica nanocomposites can be obtained by direct chemical route, such as the Polymeric Precursor Method. That methodology type permits to obtain material powders with significant specific area and porosity suitable for reactive gases or fluids permeation, which are required characteristics for application in heterogeneous catalysis process. The composite material obtained from pyrolysis of polymeric precursor has its porosity strongly dependent from precursor constitution, which affects the decomposition kinetic. In this study, it was obtained a polyester precursor based on triethylene glycol, which has been submitted at pyrolysis at 600 oC for several times in nitrogen atmosphere. The nickel-silica nanocomposite obtained through that methodology presents a residual amorphous carbon phase playing an important rule on the mechanism of pore formation. Nickel nanoparticles nucleate with sizes close to 10 nm in diameter and are highly dispersed in a hybrid amorphous carbon-silica matrix. The composite pore volume, calculated through the JBH method, presents a continuous increasing as a function of pyrolysis time, reaching more than 0.15 cc/g after 7 hours from initial decomposition process.

Particulate composite materials containing metallic phase in ceramic matrices may be obtained by direct routes with the advantage of avoiding the partial collapse of the composite structure when a subsequent step for metal insertion is carried out. The non-metallic silica-carbon matrix combines high values of pore volume and surface area with chemical refractivity and may be applied as molecular sieves, adsorbents, filters and catalyst support. The Polymeric Precursor Method is a versatile method to obtain this composite type as the metal precursor can be reduced to metallic phase by pyrolysis of organic matter. In this work, it was used three different diol chain sizes obtaining silica-carbon composites through the pyrolysis of polyester precursor at 600°C for 3 hours in closed tubular oven. It was observed a direct dependence between the amorphous carbon phase amount and the polyester chain size. All of the composite samples presented dual distribution for mesopore size, situated at 3.8 and 11 nm in diameter. However, the pore volume and surface area significantly lowers for larger polyester chain sizes.

Hydrotalcite are anionic clay material presenting LDH arrangement and high porosity and specific areas, which make it a good adsorbent for pollutant species in water. Besides that, that material type can be used as catalyst or catalyst support in several industrial processes. The most common compositions is based on metallic mix hydroxide with high content of magnesium, but their adsorptive properties arise from aluminum replacement in layer structure. The present work presents the synthesis of carbonated magnesium-aluminum hydrotalcite through the precipitation method in order to investigate the co-insertion of iron (III) in aluminum site. It was found the iron (III) co-inserted samples obtained at 100 and 200 oC for 4 hours present no substantial harming in relation to the common magnesium-aluminum composition. All of the samples presented high porosity and specific area, becoming an alternative anionic adsorptive.

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Magnesium-aluminum hydrotalcites can be co-substituted with others trivalent cations, such as iron III in aluminum site, which can be a promising way to modify the properties of that synthetic adsorptive material. In the present work, hydrotalcite containing 5 mol% iron III in co-substitution to the aluminum was prepared by precipitation process and compared with no co-substituted sample along the temperature of calcination at 100 and 500 oC for 4 hours. The calcined samples were characterized by simultaneous TG/DTA, X-ray Diffraction and nitrogen adsorption-desorption techniques. The iron (III) insertion showed positive results in order to provide more stable structure against high temperatures of calcination, which was observed by lesser structural decomposition of rhombohedral hydrotalcite and a more mesoporous structure.

Amorphous embedded nickel-silica composites can be directly obtained by Polymeric Precursor Method when the polymeric precursor is pyrolysed in controlled atmosphere. The metallic particles dispersion into the matrix composite is very important to material applications, but the resistance against the oxidation under extreme conditions is also required. In this work, nickel-silica nanocomposite sample was synthesized for containing amorphous carbon as matrix interphase through the direct route based on the Polymeric Precursor Method. The composite sample was obtained by pyrolysis of polymeric precursor at 600 oC for 1 hour under nitrogen flow and then submitted to oxidation in oxygen flow at 400 oC up to 7 hours. It was observed by Transmission Electron Microscopy the metallic nickel nanoparticles present high dispersion into matrix composite. However, in spite of the border of the composite particles are easily oxidized and originate nickel oxide phase, as proven by X-Ray Diffraction, the amorphous carbon phase acts as protective phase for the majority of the composite sample. By Nitrogen Adsorption-Desorption Isotherms at 77 K it was demonstrated the carbon phase also preserves significantly the mesoporous nature of the composite under oxidation process.