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Due to their advantages such as abundance and non-toxicity, renewable resources such as non-modified cellulose have been used as eco-friendly matrices to support metallic nanoparticles. Silver nanoparticles (AgNP) can be used efficiently for the reduction of 4-nitrophenol (4-NP), which is a pollutant compound in both industrial and agricultural wastewater. However, AgNPs tend to aggregate, thus resulting in a significant loss of catalytic activities. Fortunately, immobilization of these nanoparticles in cellulose membranes can overcome the aggregation issue. This work provides a facile method to produce non-modified cellulose membranes containing silver nanoparticles. AgNP aqueous dispersions without and with stabilizers, such as polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) were used. The as-prepared membranes are transparent, with high thermal stability and they are water-resistant. The membrane containing silver nanoparticles without extra-stabilizer (PVA or PVP) demonstrated excellent conversion of 4-NP to 4-aminophenol (4-AP). The membrane was easily removed from reaction media, no leaching of AgNP was detected allowing to use of the same membrane multiple times with great efficiency. The good catalytic performance of this membrane was attributed to the improved dispersity and narrow distribution of silver nanoparticles in the polymeric matrix.

One of the main approaches toward obtaining efficient up converting materials with practical applications involves the development of composites with synergism between components. Herein, we reported an optical temperature sensing using up-conversion fluorescence emission at 530 and 550 nm in the Er3+/Yb3+-co-doped NaYF4 nanoparticles and SBA-15/NaYF4:Yb,Er composites excited at 976 nm. Nanoparticles and composites were prepared and investigated by X-ray diffractometry, N2 adsorption–desorption isotherms, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and up-conversion photoluminescence. Spherical like NaYF4:Yb,Er nanoparticles exhibited a mixture of hexagonal and cubic phases, while the rare earth ions incorporated inside of SBA-15 mesopores crystallized in a cubic phase. Optical thermometry property was investigated in the temperature range from 30 to 90 °C, and a maximum absolute sensitivity were 0.03/°C and 0.38/°C for nanoparticles and composites, respectively. The lower temperature range makes the composites with potential for application in biological systems.

Composites of polyaniline (PANI) with MCM-41 and SBA-15 ordered mesoporous silicas were prepared by liquid and vapor monomer adsorption methods. Both methods resulted in polymer encapsulation inside the mesopores, but a higher amount was obtained using the vapor adsorption method. Composites presented a semiconductor behavior and the charge transport mechanism was consistent with a hopping process between localized states. Based on the results of one-dimensional variable range hopping (1D-VRH) conduction parameters, the SBA-15 with polyaniline incorporated by vapor adsorption was the more conductive and ordered material.

Made available in DSpace on 2022-04-28T19:47:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Mycoplasma (M.) hyopneumoniae is the main pathogen of porcine enzootic pneumonia (PEP). Its controlling is challenging, and requires alternative strategies. This study aimed to develop an oral vaccine against M. hyopneumoniae using a nanostructured mesoporous silica (SBA-15) as an adjuvant, and compare its effect with an intramuscular (IM) commercial vaccine (CV). Fifty 24 day-old M. hyopneumoniae-free piglets composed five equal groups for different immunization protocols, consisting of a CV and/or oral immunization (OI). Control piglets did not receive any form of immunization. All piglets were challenged with M. hyopneumoniae strain 232 on D49 by tracheal route. IgA antibody response in the respiratory tract, bacterial shedding and serum IgG were evaluated. The piglets were euthanized on 28 (D77) and 56 (D105) days post-infection. Lung lesions were macroscopically evaluated; lung fragments and bronchoalveolar fluid (BALF) were collected for estimation of bacterial loads by qPCR and/or histopathology examination. All immunization protocols induced reduction on Mycoplasma-like macroscopic lung lesions. IgA Ab responses anti-M. hyopneumoniae, the expression of IL-4 cytokine and a lower expression of IL-8 were induced by CV and OI vaccines, while IgG was induced only by CV. Oral immunization using silica as a carrier-adjuvant can be viable in controlling M. hyopneumoniae infection. School of Agricultural and Veterinarian Sciences São Paulo State University (Unesp) Department of Chemistry Federal University of São Paulo (UNIFESP) Butantan Institute Physics Institute University of São Paulo (USP) School of Agricultural and Veterinarian Sciences São Paulo State University (Unesp) FAPESP: #2018/12742-5 FAPESP: #2019/19710-4

A review is presented on the strategic use of scattering and imaging tools to design immunologic complexes based on porous silica for oral vaccine formulations., This article summarizes developments attained in oral vaccine formulations based on the encapsulation of antigen proteins inside porous silica matrices. These vaccine vehicles show great efficacy in protecting the proteins from the harsh acidic stomach medium, allowing the Peyer’s patches in the small intestine to be reached and consequently enhancing immunity. Focusing on the pioneering research conducted at the Butantan Institute in Brazil, the optimization of the antigen encapsulation yield is reported, as well as their distribution inside the meso- and macroporous network of the porous silica. As the development of vaccines requires proper inclusion of antigens in the antibody cells, X-ray crystallography is one of the most commonly used techniques to unveil the structure of antibody-combining sites with protein antigens. Thus structural characterization and modelling of pure antigen structures, showing different dimensions, as well as their complexes, such as silica with encapsulated hepatitis B virus-like particles and diphtheria anatoxin, were performed using small-angle X-ray scattering, X-ray absorption spectroscopy, X-ray phase contrast tomography, and neutron and X-ray imaging. By combining crystallography with dynamic light scattering and transmission electron microscopy, a clearer picture of the proposed vaccine complexes is shown. Additionally, the stability of the immunogenic complex at different pH values and temperatures was checked and the efficacy of the proposed oral immunogenic complex was demonstrated. The latter was obtained by comparing the antibodies in mice with variable high and low antibody responses.

Papain has bacteriostatic and anti-inflammatory properties and has been shown to be effective in the healing process of wounds, injuries, and ulcers by breaking down fibrinous material into necrotic tissue. However, papain is unstable and easily denatures or deactivates preventing their broad industrial application. In this work, papain was incorporated into SBA-15 ordered mesoporous silica, with the aim of improving its stability, as well as its encapsulation yield and influence of the reaction time on its stability and enzymatic activity. By small-angle X-ray scattering it was possible to verify that the papain is a globular and slightly elongated protein, likely dimeric, with a maximum size of ~6.0 nm, which favors its inclusion in the SBA-15 mesopores (~10 nm). The biocomposites (SBA-15:papain) were characterized by several physical-chemical techniques. The results indicated that the papain was incorporated into the SBA-15 mesopores. The biocomposites exhibited higher thermal degradation temperature than pure papain and did not show cytotoxic potential. The papain enzymatic activity was maintained, with the best performance for the samples prepared with 30 wt% of papain. The results also showed that the 3D cell culture system is better suited for biocomposites that present a cell disruption mechanism.

Electrochemical procedures have emerged as a powerful tool for the synthesis of complex organic molecules including transformation of natural products. In this study, the electrosynthesis of biseugenol in MeOH afforded one new oxidized derivative, which was characterized as methoxyloxo-biseugenol (MOB) by nuclear magnetic resonance (NMR) and electrospray ionization-high resolution mass spectrometry (ESI-HRMS) analysis. Since biseugenol was previously described as a cytotoxic natural product, MOB was also tested against tumoral cells B16F10-Nex2 (murine metastatic melanoma) and SKMEL-25 (human metastatic melanoma) as well as against nontumoral cells MØ Raw 264.7 (murine macrophage immortalized) and HUVEC (human umbilical endothelium). As results, MOB showed inhibitory concentration that affects 50% of cells (IC50)values of 9.5 ± 1.6 mg mL-1 (B16F10Nex2), 13.2 ± 2.5 mg mL-1 (SKMEL-25), 19.9 ± 3.5 mg mL-1 (MØ Raw 264.7) and 36.3 ± 7.4 mg mL-1 (HUVEC). Therefore, selectivity index (SI) values of MOB to tumoral cells B16F10Nex2 and SKMEL-25 were calculated as 2.1 and 2.8, respectively, higher than biseugenol (1.4 and 1.7, respectively). Based on these results, the superior cytotoxic activity of MOB in comparison to biseugenol could be associated, at least in part, to the presence of a non-aromatic ring and a conjugated carbonyl system instead of a phenol moiety.

Urea’s thermal instability and burning on sensitive skin can cause problems for cosmetic formulations. To overcome these drawbacks, urea was incorporated into ordered mesoporous silica (SBA-15). SBA-15 was synthesized using tetraethyl orthosilicate and Pluronic® P123 in an acid medium. Urea (20 wt.%) was incorporated into calcined SBA-15 by the incipient wetness impregnation method. Several techniques were used to characterize the samples. Skin hydration and transepidermal water loss were measured using Corneometer® CM 825 PC and Tewameter® 300 TM. Results showed that the structural properties of SBA-15Urea were similar to pure SBA-15, indicating that SBA-15 remained structured even after urea incorporation. Nitrogen physisorption data showed the volume and surface area of the pores in SBA-15Urea were much lower than those in SBA-15, demonstrating that urea was deposited inside the mesopores. In vivo moisturization studies revealed that SBA-15Urea was not able to reduce transepidermal water loss compared to the other products and control, while forming a non-occlusive surface film on the skin. We conclude that incorporation of urea in the pores of the inorganic SBA-15 matrix is a promising approach to enhancing its stability and providing a prolonged moisturizing effect.

SBA-15 ordered mesoporous silica can be considered a promising inorganic nanocarrier with emerging potential as an oral vaccine adjuvant. In this study, we investigated its application in the encapsulation of the diphtheria anatoxin (dANA). We observed a considerable preservation of dANA secondary and tertiary structures, even after the drying process by means of Circular Dichroism (CD) and fluorescence spectroscopies. Antigen loading was assessed at a number of different ratios of adjuvant-to-antigen using a combination of nitrogen adsorption porosimetry and Small Angle X-ray Scattering (SAXS). Our data showed that the mass ratio of 1:10 (dANA:SBA-15) is recommended for total encapsulation of dANA in the mesopores, considering that at this relative mass concentration antigen clustering was avoided, which is deleterious effect for immunization purposes. dANA release in mimetic intestine fluid, at a pH equal to 6.8, was followed by in-situ SAXS measurements and shown to be slow, being more pronounced after 6 h and continuous up to 35 h. Finally, the immunogenic complex was tested in isogenic Balb C mice by oral and subcutaneous immunization routes, including a comparison with the only permitted adjuvant for human use, aluminum hydroxide. A higher antibody titer was obtained by subcutaneous and oral administration routes using SBA-15 as the vehicle of dANA, compared with the conventional aluminum hydroxide, demonstrating the viability to use this ordered mesoporous silica in the formulation of oral vaccines, as already proved for the Virus Like Particles (VLP) Hepatitis B (HBsAg) case.

Aim: We evaluated the effects of the incorporation of zinc oxide (ZnO) nanoparticles in a mesoporous matrix, aiming to improve the textural, structural and morphological properties and verify their safety so that they can be applied in sunscreen cosmetics. Materials and Methods: ZnO nano­particles were incorporated into an ordered mesoporous silica matrix known as Santa Barbara Amorphous-15 (SBA-15), using post-synthesis methodology. The resulting nanocomposites were characterized using X-ray diffraction, small angle X-ray scattering, N2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy, scanning electron microscopy and predicted in vitro sun protector factor (SPF) estimation. Effectiveness and safety were evaluated by antimicrobial activity, in vitro cell toxicity and non-invasive multi-photon tomography with fluorescence lifetime imaging. Results: The structure of the nanocomposites was similar to that of SBA-15, with little perturbation caused by ZnO incorporation. Nanocomposites had an increased in vitro SPF, reduced cytotoxic activity and favourable antimicrobial properties compared to ZnO. ZnO:SBA-15 nanocomposites exhibited no measurable toxicity when applied to human skin in vivo. Conclusion: Due to their suitable physicochemical properties and improved safety compared to bare ZnO nanoparticles, the ZnO:SBA-15 nanocomposites show promise for use in cosmetic applications.

In this work we analyze the effect of adding CuO to a NiO/Ce0.9Zr0.1O2 oxide by in situ X-ray absorption near-edge structure XANES technique in Ce L3, Ni K and Cu K absorption edges in terms of sample reducibility and catalytic activity. The oxidation states of Ce, Ni and Cu cations are followed up during temperature programmed reduction (TPR) experiments in diluted hydrogen and during catalytic tests for partial oxidation of methane (POM) reaction. Redox behavior was correlated to conventional fixed bed reactor results. The effect of firing temperature, crystallite size, CeO2-ZrO2 support and the presence of Cu and/or Ni as an active phase is also analyzed. Results showed a beneficial effect of CuO addition in terms of Ce and Ni reduction. A stronger interaction of NiO species with the support was revealed upon analysis of XANES reduction profiles in sample NiO/ZDC in contrast to bimetallic CuO-NiO/ZDC sample. Reduction onset temperature was found to depend on Ni crystallite size, being markedly promoted when samples exhibited low values of crystallite size both in supported and non-supported CuO-NiO species. In situ catalytic experiments for partial oxidation of methane showed a clear interplay between the redox behavior from the Ce in the CeO2-ZrO2 support and the Ni from the active phase. Sample NiO/ZDC exhibited a continuous reduction of Ce cations in CH4:O2 feed flow, carbon formation was detected in X-ray Powder Diffraction (XPD) patterns and Ni re-oxidation was found to take place, clear indications of catalyst deactivation. In contrast, sample CuO-NiO/Ce0.9Zr0.1O2 displayed a slight re-oxidation of Ce and no re-oxidation of Ni altogether with the suppression of carbon formation. Fil: Toscani, Lucía María. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina Fil: Zimicz, Maria Genoveva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina Fil: Martins, Tereza S.. Universidade de Sao Paulo; Brasil Fil: Lamas, Diego Germán. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Larrondo, Susana Adelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina

In this work, we analyze Sm2O3-doped CeO2 (SDC) nanopowders and NiO/SDC nanocomposites in terms of sample reducibility and catalytic activity for partial oxidation of methane. We assess the role of the average crystallite size and specific surface area in Ni and Ce reduction kinetics by in-situ X-ray absorption spectroscopy experiments in diluted H2 and CH4/O2 mixtures. Our results indicate that crystallite size and surface area play a key role in CH4 activation through modification of the sample redox behavior. The oxidation of the metallic phase is the main cause of sample deactivation. A clear relationship is established between the temperature of maximum Ni oxidation rate and grain size. An interplay between Ce atoms from the support and Ni from the active phase was observed during the experiments, evidencing a complex relationship between oxygen vacancy concentration and catalytic activity. A high Ce3+ content in catalyst support was detrimental to catalytic activity

In tropical environments, nutrient-poor soils are commonly found, leading to high fertilizers application rates to support agricultural activities. In contrast, anthropogenic activities generate large amounts of effluents containing nitrogen. In this study, two minerals (natural zeolite and vermiculite) were tested to remove NH4+ from an industrial effluent with high pH and contents in Na+ and K+. Afterwards, they were tested as an alternative slow-release fertilizer in the soil. To verify the best conditions to adsorb NH4+, batch tests were conducted using synthetic solutions and an industrial effluent. In general, the efficiency of both minerals in removing NH4+ was high (85% for zeolite and almost 70% for vermiculite) as well as the ability to decrease the industrial effluent pH. In this process, more NH4+ and K+ ions were removed in comparison with Na+, which remained in solution. These minerals were tested as slow-release fertilizers by leaching with distilled water (both minerals releasing 2 mg L−1 NH4+) and with an acid solution (releasing 10 mg L−1 NH4+ from zeolite and 50 mg L−1 NH4+ from vermiculite—corresponding only to 12% of total NH4+ retained by zeolite and 29% by vermiculite). During the test of soil incubation with zeolite-NH4+, the NH4+ ions of the exchangeable sites were retained for a longer period, minimizing their loss by leaching and biological nitrification. Consequently, soil acidification was prevented. Therefore, both minerals showed high efficiency in removing NH4+ from solution which can then be slowly released as a nutrient in the soil.

Nanosized titanium dioxide (TiO2) has been extensively studied due to its unique properties and broad applicability. However, to our knowledge, the assessment on how reaction media and synthesis routes affect TiO2 properties synthesized with SBA-15 type mesoporous silica is unprecedented. In this work, SBA-15/TiO2 nanocomposites were prepared in different reaction media, varying ionic liquids (CMITf2N and CMIBF4) with and without isopropyl alcohol. X-ray diffraction results showed that CMIBF4 greatly favors TiO2 anatase crystalline phase, and a single phase material was obtained using 0.032 of CMIBF4 without alcohol. On the other hand, the presence of CMITf2N slightly favored TiO2 rutile crystalline phase. Small Angle X-ray diffraction patterns revealed that ordered mesoporous SBA-15/TiO2 nanocomposites were obtained with lower ionic liquid concentration, whilst materials prepared with higher concentration lost their ordered mesoporous structure. Scanning electron microscopy images showed that materials prepared with ionic liquid and isopropyl alcohol displayed much smaller SBA-15 particle size: around 0.1 μm, instead of the standard 1 μm. Nitrogen adsorption–desorption analysis showed that the nanocomposites exhibited a narrow pore size distribution with high surface areas of up to 680 m2/g, pore volumes of up to 1.8 cm3/g and mean pore diameter of up to 10.4 nm, thus being very promising for application in photocatalysis and photoprotection.

The uniform structural pores architecture in nanoscopic domain of ordered mesoporous silicas, such as MCM-41 and SBA-15, can be used as a confined space to produce nanomaterials with controlled dimensions and cylindrical shape. In this study, we report the synthesis of a ternary nanocomposite constituted of silver nanoparticles and polyaniline concomitantly produced in the presence of SBA-15. The synthetic process involved firstly the adsorption of aniline vapor into the silica pores followed by its polymerization by reacting with the silver salt (AgN(SO2CF3)2) solubilized in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (BMImTf2N). With this synthetic approach the reaction proceeded quickly and efficiently, generating the silver-polyaniline nanocomposite mainly into pores and without collapsing the silica mesostructure. Surface area and pore volume of SBA-15 decreased after the reaction proceeded, indicating the formation of polyaniline and silver nanoparticles composite inside the pores and complementary analysis evidenced the presence of some silver nanoparticles outside pores. The measured electrical conductivity of the ternary composite in the order of 10−6 S cm−1 was coherent to the presence of the polymer and silver nanoparticles inside the pores of the insulator SBA-15 mesostructure rather than on the surface of the particles. The prepared SBA-15 ternary nanocomposite presented higher silver nanoparticles loadings of and superior surface area than the ones observed to small pore silicas, such MCM-41. The improvement in textural properties of the nanocomposite are favorable aspects for the further development of sensors and catalysts.

The purpose of this study was to evaluate the effect of composition and characteristics of liquid crystalline phases (LCPs) on cutaneous delivery of methylene blue (MB). LCPs were obtained by mixing Brij97® with water at various ratios; Brij97®:water at 8:2 (F8:2), 7:3 (F7:3), and 6:4 (F6:4) were selected, and MB was incorporated at 0.1%. F8:2 and F7:3 exhibited textures and small angle X-ray scattering (SAXS) patterns corresponding to lamellar phase, whereas F6:4 displayed characteristics of hexagonal phase. All three LCPs were stable for 9 months, and exhibited thixotropic pseudoplastic behaviour. Increasing water content increased viscosity. All three LCPs released less (3.2- to 6.6-fold) MB than control gel (3.0% hydroxyethylcellulose (HEC) + 0.1% MB), demonstrating their ability to sustain release. Despite the lower release, all LCPs improved skin retention of MB at 6 h post-application (1.3- to 2.1-fold) compared to the control gel. Among the LCPs, F8:2-mediated skin retention of MB was more pronounced, followed by F7:3. Consistent with the increased penetration, transepidermal water loss (TEWL) also increased after treatment with the LCPs (2.0–2.8 fold), which suggests their influence on skin barrier. Irritation studies by Hen’s Egg Test – Chorioallantoic Membrane (HET-CAM) suggest that F7:3 and F6:4 may be better tolerated by the skin than F8:2.

This work reports the synthesis and characterization of mesoporous NiO/ZrO2-CeO2 composites. These materials are still being developed due to their excellent morphological and structural properties, especially for solid oxide fuel cells (SOFCs) anodes. A soft chemical route using a polymeric template was utilized to synthesize the samples. The structure after two different calcination processes at 400 °C and 540 °C was studied by X-ray diffraction and Rietveld refinement, before and after NiO loading. Nitrogen adsorption, scanning/transmission electron microscopy and small angle X-ray scattering revealed a nanocrystalline bi-phasic porous material. Temperature programmed reduction experiments showed higher Ni and Ce reduction values for samples calcined at 400 °C and 540 °C, respectively. Methane conversion values in the temperature range studied were similar for both calcination temperatures, showing 50% CH4 conversion around 550 °C and 80% around 650 °C. However, a sample calcined at 400 °C exhibited better morphological and textural properties leading to an enhancement in NiO and CeO2 reducibility that might be responsible for an improvement in oxygen surface exchange and gasification of carbon species in catalytic experiments. Fil: Bacani, R.. Universidade de Sao Paulo; Brasil Fil: Toscani, Lucía María. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina Fil: Martins, T. S.. Universidade Federal de Sao Paulo; Brasil Fil: Fantini, M. C. A.. Universidade de Sao Paulo; Brasil Fil: Lamas, Diego Germán. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Larrondo, Susana Adelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina

Nanosized titanium dioxide (TiO2) is used in different applications that require a specific crystalline structure. In this work, SBA-15:TiO2 nanocomposites (80 mol% Si and 20 mol% Ti) were prepared using two different synthesis routes (direct and post-synthesis), with and without acetylacetone and a modified hydrothermal route (M). The small angle X-ray diffraction data showed that all nanocomposites are ordered mesoporous materials. N2 adsorption-desorption analysis showed that the materials exhibit a narrow pore size distribution with mean pore diameters up to 9.9 nm, high surface areas up to 810 m2 g−1 and large pore volumes up to 1.3 cm3 g−1. The analysis of the morphology by scanning electron microscopy (SEM) revealed different particle shapes due to the inclusion of Ti together with the Si source in the direct synthesis route. The characterization by X-ray diffraction revealed that the presence of acetylacetone and the M route in the direct synthesis method favored the formation of the rutile phase (>90%). Additionally, the posterior inclusion of Ti (post-synthesis) favored the formation of single phase anatase (100%). In addition, the SEM images showed that the silica particle size is about 1 μm, thus being biologically safe and making the composite a very promising photoprotector.

In this work, we have shown the preparation of polyaniline (PANI) and mesoporous ordered silica (SBA-15) composites. PANI/SBA-15 composites with different weight ratios were prepared in order to evaluate the electrical conduction mechanism. The analysis of the differential activation energy was carried out for composites, allowing the classification of the variable range hopping as one dimensional for the composites. The hopping parameter as a function of the sample mass ratio indicates that the insertion of aniline into the mesopores improves its intrinsic conductivity. A fibrilar morphology of the conducting PANI is formed by a controlled amount of the added polymer into SBA-15. It was confirmed by SEM and TEM analysis that the composites prepared with different PANI contents have different morphologies, indicating that the amount of polyaniline is crucial to obtain distinct morphologies. SAXS, NAI, TEM and SEM show that SBA-15 maintains its structure even after the polymerization process and the polymer is dispersed on the inorganic matrix. The parameters determined by the investigation of variable range hopping conduction by the differential activation energy method show that the PANI produced in these composites have higher electrical conductivity than pure PANI, possibly due to the improvement of the interparticle, interchain and intrachain processes for the charge transport, which are intimately related to the polymer morphology, fact coherent with SEM and TEM data.

This work reports the application of an ionic liquid (1-butyl-3-methylimidazolium bromide, BMImBr) in the microwave assisted extraction (MAE) of metabolites from fruits of Schinus terebinthifolius. Dried fruits were individually extracted using BMImBr:H2O 1:1, v/v (experiment 1) and pure H2O (experiment 2) by MAE (10 min at 60 oC). After partition using EtOAc, the yield to experiment 1 was about 23% while to experiment 2 was 0.1%. The EtOAc fraction obtained from experiment 1 was purified by chromatographic methods to afford 3-oxotirucalla-7,24Z-dien-27-oic acid, 3a-hydroxytirucalla-7,24Z-dien-27-oic acid, 3a-acetoxytirucalla-7,24Z-dien-27-oic acid, gallic acid, and ethyl gallate, being the first occurrence of the third compound as natural product. Cytotoxic activity was evaluated in vitro against cancer cell lines (A2058, HeLa, SiHa, HCT, SKBR-3, U87, and B16F2Nex2), being 3a-acetoxytirucalla-7,24Z-dien-27-oic acid the more active metabolite with IC50 ranging from 10.9 ± 1.3 to 17.3 ± 1.4 µg mL-1, lower than that determined to positive control cisplatin.

In this work the synthesis of cubic, FDU-1 type, ordered mesoporous silica (OMS) was developed from two types of silicon source, tetraethyl orthosilicate (TEOS) and a less expensive compound, sodium silicate (Na 2 Si 3 O 7 ), in the presence of a new triblock copolymer template Vorasurf 504 (EO 38 BO 46 EO 38 ). For both silicon precursors the synthesis temperature was evaluated. For TEOS the effect of polymer dissolution in methanol and the acid solution (HCl and HBr) on the material structure was analyzed. For Na 2 Si 3 O 7 the influence of the polymer mass and the hydrothermal treatment time were the explored experimental parameters. The samples were examined by Small Angle X-ray Scattering (SAXS) and Nitrogen Sorption. For both precursors the decrease on the synthesis temperature from ambient, −25 °C, to −15 °C improved the ordered porous structure. For TEOS, the SAXS results showed that there is an optimum amount of hydrophobic methanol that contributed to dissolve the polymer but did not provoke structural disorder. The less electronegative Br − ions, when compared to Cl − , induced a more ordered porous structure, higher surface areas and larger lattice parameters. For Na 2 Si 3 O 7 the increase on the hydrothermal treatment time as well as the use of an optimized amount of polymer promoted a better ordered porous structure.

Titanium dioxide with and without the addition of neodymium ions was prepared using sol–gel and precipitation methods. The resulting catalysts were characterized by thermal analysis, X-ray diffraction and BET specific surface area. Neodymium addition exerted a remarkable influence on the phase transition temperature and the surface properties of the TiO 2 matrix. TiO 2 samples synthesized by precipitation exhibit an exothermic event related from the amorphous to anatase phase transition at 510 °C, whereas in Nd-doped TiO 2 this transition occurred at 527 °C. A similar effect was observed in samples obtained using sol–gel method. The photocatalytic reactivity of the catalysts was evaluated by photodegradation of Remazol Black B (RB) under ultraviolet irradiation. Nd-doped TiO 2 showed enhanced photodegradation ability compared to undoped TiO 2 samples, independent of the method of synthesis. In samples obtained by sol–gel, RB decoloration was enhanced by 16% for TiO 2 doped with 0.5% neodymium ions.

Three different cerium citrate-based precursors were used for synthesizing CeO2 through thermal treatment. Three morphological types of CeO2 were obtained. Characterization of these oxides was carried out by XRD patterns, SEM microscopy, N2 adsorption isotherms, Raman spectroscopy, zeta potential, and UV/Vis luminescence. Ozonation of phenol catalyzed by CeO2 was studied as a representative reaction of environmental interest. The differences on the catalytic activity showed by these three oxides could be correlated to amounts of Ce3+ on CeO2 surface and, consequently, to the demand for oxygen needed to burn each precursor.

Two series of lanthanide oxides with different morphologies were synthesized through calcinations of two types of citrate polymeric precursors. These oxides were characterized by XRD patterns, SEM electronic microscopy, and N2 adsorption isotherms. SEM microscopy analysis showed that the calcination of crystalline fibrous precursors [Ln2(LH)3·2H2O] (L = citrate) originated fibrous shaped particles. On the other hand, the calcination of irregular shaped particles of precursors [LnL·xH2O] originated irregular shaped particles of oxide, pointing out a morphological template effect of precursors on the formation of the respective oxides.

The synthesis of organolanthanide compounds identified as LnCp* (MS)2PzA, Ln = Sm, Tb, Yb (MS = methanesulfonate, Cp* = pentamethylcyclopentadienyl, and PzA = pyrazinamide), by the reaction of coordination compounds Ln (MS)3(PzA)4 with NaCp in THF was reported. The complexes were formulated according to elemental analyses. complexometric titration with EDTA (%Ln), and 1H NMR. IR spectroscopy revealed that PzA coordinates with lanthanide (III) ions and methanesulfonate coordinates via oxygen atoms in a non-equivalent manner. In preliminary catalytic studies, these compounds were active in styrene polymerization that used MAO as a cocatalyst with an activity of 12.3 kg PS molSm−1h−1. Differential scanning calorimetry (DSC) of polystyrene showed that the polymer was mainly atactic.

In this work the synthesis of ZrO2-CeO2 and ZrO2-CeO2/SiO2 were developed, based on the process to form ordered mesoporous materials such as SBA-15 silica. The triblock copolymer Pluronic P-123 was used as template, aiming to obtain crystalline single phase walls and larger specific surface area, for future applications in catalysis. SAXS and XRD results showed a relationship between ordered pores and the material crystallization. 90% of CeO2 leaded to single phase homogeneous ceria-zirconia solid solution of cubic fluorite structure (Fm3m). The SiO2 addition improved structural and textural properties as well as the reduction behavior at lower temperatures, investigated by XANES measurements under H2 atmosphere. Fil: Bacani, R.. Universidade de Sao Paulo; Brasil Fil: Martins, T. S.. Universidade Federal de Sao Paulo; Fil: Fantini, M. C. A.. Universidade de Sao Paulo; Brasil Fil: Lamas, Diego Germán. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

FDU-1 is a highly ordered, large-pore silica with a cage-like mesoporous cubic structure. FDU-1 was synthesized from tetraethyl orthosilicate (TEOS) in the presence of poly(ethylene oxide)–poly(butylene oxide)–poly(ethylene oxide) triblock copolymer (PEO–PBO–PEO) template in strongly acid media, using a microwave oven as heating source. Rare earth complexes were encapsulated in ordered mesoporous silica in order to improve their thermal stability, necessary for applications. Eu(dbm) 3 · TPPO (dbm = dibenzoylmethane and TPPO = triphenylphosphine oxide) and Eu(pic) 3 · 2Leu · 5H 2 O (pic = picrate and Leu = l -leucine) were encapsulated into FDU-1 silica and modified FDU-1 silica by 3-aminopropyltriethoxysilane (APTES). Thermogravimetry/derivative thermogravimetry (TG/DTG) showed that the decomposition temperature increased after encapsulation of the complex. Small angle X-ray diffraction (SAXRD) results showed that the mesoporous silica remains ordered after the encapsulation of the europium complexes. Rutherford back-scattering spectrometry (RBS) revealed a much higher Eu encapsulation for the dibenzoylmethane complex compared to picrate and, with a weight percent similar to the nominal concentration of Eu set at the synthesis process. All infrared spectra are similar and present the profile of amorphous silica. The complexes in FDU-1 silica still present luminescence.

Rare earth picrate complexes with L-leucine (Leu) were synthesized and characterized. Elemental analysis (CHN), EDTA titrations and thermogravimetric data suggest a general formula RE(pic)32Leu⋅5H2O (RE=La–Lu, Y and pic=picrate). IR spectra indicate the presence of water and suggest that L-leucine is coordinated to the central ion through the nitrogen of the aminogroup. The absorption spectrum of the solid Nd compound indicates that the metal-ligand bonds show a weak covalent character. Emission spectra and biexponential behavior of the luminescence decay of the Eu compound suggest the existence of polymeric species. Thermal analysis results indicate that all the compounds present a similar behavior, with five major thermal decomposition steps. The final products are rare earth oxides. A slow heating rate is necessary to observe all decomposition steps.

The history of the rare earths is rich in innovation and these elements have been the object of study of a number of scientists. Rare earths are used practically in almost all aspects of life and these applications are due to their outstanding properties, mainly spectroscopic and magnetic. In industry, the applications of rare earths are many, such as in catalysis, phosphors, magnetism, glass and lasers. In biological systems, rare earths are used, for example, as luminescent probes in the investigation of binding sites in proteins, labels in immunoassays and in noninvasive tests.

Uranyl nitrate complexes with diphenylsulfoxide (DPSO) and dibenzylsulfoxide (DBSO) were synthesized and characterized by CHN elemental analyses, infrared absorption spectra, X-ray powder diffraction, visible luminescence spectra and thermal analyses (TG and DTG). The complexes present the compositions UO2(NO3)2(DPSO)2 and UO2(NO3)2(DBSO)2. Infrared spectra show a shift of νSO to lower frequencies, indicating bonding through the sulfoxide oxygen. The nitrate bands indicate that they are coordinated as bidentate ligands. In both complexes thermal decomposition yields U3O8 as final product. Both complexes present a strong green luminescence, both at room temperature and 77 K, presenting four bands with vibronic structures partially resolved at low temperature. The X-ray powder patterns of these complexes are different, therefore, both structures were determined by single-crystal X-ray diffraction. In both complexes the U(VI) occupies a symmetry center. Uranyl oxygen atoms, nitrate ions and neutral ligands are perpendicular with respect to each other.

Rare-earth picrate complexes with l -arginine were synthesized and characterized. Analysis of carbon, hydrogen, nitrogen and thermal analysis data suggest a general formula Ln(pic) 3 ·2 l -Arg·2H 2 O (Ln=La–Lu, Y, pic=picrate, l -Arg=arginine). IR spectra indicate the presence of water molecules and suggest that l -arginine is coordinated to the central ion through the nitrogen of the amine group. Bands due to picrate ions also indicate that at least in part they are coordinated as bidentate through the phenoxo group and one oxygen of an ortho -nitro group. X-ray diffraction powder pattern results indicate that these complexes are very similar in structure. The parameters obtained from the absorption spectrum of the solid Nd compound indicated that the metal–ligand bonds present weak covalent character. The emission spectra of the Eu compound indicate the existence of different europium coordinaton environments. Thermal analyses results indicated that all the compounds present a similar behavior.

Complexes of lanthanide picrates with glycine were synthesized and characterized. Analysis of carbon, hydrogen, nitrogen and thermal analysis data suggest a general formula Ln(pic)3·2Gly·xH2O (Ln=La–Lu and Y; pic=picrate; Gly=glycine; x=4 for Gd–Lu, Y and x=5 for La–Eu). IR spectra indicate the presence of water molecules and suggest that glycine is coordinated to the central ion through the nitrogen of the amine group. Bands due to picrate ions also indicate that at least in part they are coordinated as bidentate through the phenoxo group and one oxygen of an ortho-nitro group. Conductance measurements in acetone show that the complexes behave as non-electrolytes. X-ray powder data show the existence of two isomorphous series. The parameters obtained from the absorption spectrum of the Nd compound indicated that the metal–ligand bonds present weak covalent character. The spectrum of the europium compound was interpreted in terms of C2v symmetry. The thermal analyses results indicated that all the compounds present a similar behavior.

The aim of this work was to analyze the local atomic environment around lanthanide atoms anchored inside silica matrices by means of X-ray absorption spectroscopy (XAS). Europium and cerium complexes were incorporated in cubic FDU-1 and SBA-16 ordered mesoporous silica (OMS) by a post-synthesis method. Small angle X-ray scattering (SAXS) showed the presence of an ordered arrangement of pores for all investigated samples. A much higher Eu incorporation for the dibenzoylmethane complex is attained compared to picrate complex with a weight percent similar to the nominal concentration of Eu, as determined by Rutherford back-scattering spectrometry (RBS). The XAS results showed that the local atomic arrangement around Eu is composed by a first neighbor sphere similar to the complex and different second neighbors compared to pristine material, indicating an interaction of the complexes with the silica walls, in such an extent that it does not interfere on the complexes luminescent properties. The first and second spheres around the incorporated Ce are analogous to the pure cerium picrate complex, showing that the complex is anchored on the porous surface. The solvent does not interfere on the local atomic structure, but on the incorporation capacity.

Iron was successfully incorporated in FDU-1 type cubic ordered mesoporous silica by a simple direct synthesis route. The (Fe/FDU-1) samples were characterized by Rutherford back-scattering spectrometry (RBS), small angle X-ray scattering (SAXS), N 2 sorption isotherm, X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). The resulting material presented an iron content of about 5%. Prepared at the usual acid pH of −0.3, the composite was mostly formed by amorphous silica and hematite with a quantity of Fe 2+ present in the structure. The samples prepared with adjusted pH values (2 and 3.5) were amorphous. The samples’ average pore diameter was around 12.0 nm and BET specific surface area was of 680 m 2 g −1 . Although the iron-incorporated material presented larger lattice parameter, about 25 nm compared to pure FDU-1, the Fe/FDU-1 composite still maintained its cubic ordered fcc mesoporous structure before and after the template removal at 540 °C. The catalytic performance of Fe/FDU-1 was investigated in the catalytic oxidation of Black Remazol B dye using a catalytic ozonation process. The results indicated that Fe/FDU-1 prepared at the usual acid pH exhibited high catalytic activity in the mineralization of this pollutant when compared to the pure FDU-1, Fe 2 O 3 and Fe/FDU-1 prepared with higher pH of 2 and 3.5.

Zirconia-ceria solid-solutions are extensively used as promoters for three-way catalysts, in addition, these materials can be used as anodes in solid oxide fuel cells (SOFCs) operated with hydrocarbons. The structural features of ZrO2-CeO2 materials in combination with oxygen storage/release capacity (OSC) are crucial for various catalytic reactions. The direct use of hydrocarbons as fuel for the SOFC (instead of pure H2), without the necessity of reforming and purification reactors can improve global efficiency of the system. The samples preparation method was developed using Zr and Ce chloride precursors, HCl aqueous solution, Pluronic P123, NH4OH and a Teflon autoclave. The samples were dried and calcined, until 540°C. The NiO impregnation was made with an ethanol dispersion of Ni(NO3)×6H2O, calcinated in air until 350°C for 2 hours. In-situ XANES experiments are capable to evaluate the reduction/oxidation potencial of Ni and Ce species in ZrO2-CeO2/Ni samples during partial/total methane oxidation and reduction reactions with H2. The experiments at the Ni K-edge/Ce L3-edge were collected at the LNLS D06A-DXAS beam line in transmission mode, using a Si(111) monochromator and a CCD camera as detector. The data were acquired during a series of temperature programmed reduction steps (TPR), under a 5% H2/He until 600°C, and mixtures of 20%CH4:5%O2/He with 2:1, 1:1 and 1:2 ratios. After each process with CH4 and O2, a TPR procedure was performed in order to evaluate the reduction capacity of the sample after reactions with CH4. The results demonstrated that NiO embedded in the porous ZrO2-CeO2 matrix, reduces at lower temperatures than standard NiO, measured in the same conditions, revealing that the mesoporous support improves the reduction of impregnated NiO. For both edges, there was formation of H2 during partial methane oxidation at 600°C. The total oxidation of methane was observed in lower temperatures (500°C). These results reveal that a high ceria content (90%) could be a great candidate for the SOFC anode.