Optical, mechanical and surface properties of amorphous carbonaceous thin films obtained by plasma enhanced chemical vapor deposition and plasma immersion ion implantation and deposition

Diverse amorphous hydrogenated carbon-based films (a-C:H, a-C:H:F, a-C:H:N, a-C:H:Cl and a-C:H:Si:O) were obtained by radiofrequency plasma enhanced chemical vapor deposition (PECVD) and plasma immersion ion implantation and deposition (PIIID). The same precursors were used in the production of each pair of each type of film, such as a-C:H, using both PECVD and PIIID. Optical properties, namely the refractive index, n, absorption coefficient, α, and optical gap, ETauc, of these films were obtained via transmission spectra in the ultraviolet-visible near-infrared range (wavelengths from 300 to 3300 nm). Film hardness, elastic modulus and stiffness were obtained as a function of depth using nano-indentation. Surface energy values were calculated from liquid drop contact angle data. Film roughness and morphology were assessed using atomic force microscopy (AFM). The PIIID films were usually thinner and possessed higher refractive indices than the PECVD films. Determined refractive indices are consistent with literature values for similar types of films. Values of ETauc were increased in the PIIID films compared to the PECVD films. An exception was the a-C:H:Si:O films, for which that obtained by PIIID was thicker and exhibited a decreased ETauc. The mechanical properties - hardness, elastic modulus and stiffness - of films produced by PECVD and PIIID generally present small differences. An interesting effect is the increase in the hardness of a-C:H:Cl films from 1.0 to 3.0 GPa when ion implantation is employed. Surface energy correlates well with surface roughness. The implanted films are usually smoother than those obtained by PECVD. ©2013 Elsevier B.V. All rights reserved.

UV filters in water samples: Experimental design on the SPE optimization followed by GC-MS/MS analysis

Esse estudo descreve o desenvolvimento e otimização de um método de extração em fase solida (SPE) para análise dos filtros ultravioletas (UV): benzofenona-3 (BP-3), etilhexil salicilato (ES), etilhexil metoxinamato (EHMC) e octocrileno (OC) em matrizes ambientais. Um planejamento fatorial fracionário (PFF) 25-1 foi empregado na avaliação das variáveis significativas do método de extração. As condições experimentais otimizadas da avaliação estatística foram: capacidade do cartucho de 500 mL, eluente acetato de etila, metanol como solvente de lavagem (10% em água, v/v) and volume do eluente de 3 × 2 mL e pH 3. Os parâmetros analíticos avaliados foram satisfatõrios, apresentando linearidade de 100 a 4000 ng L -1, recuperaç ões para os quatro níveis de fortificação (Limite de Quantificação do Método, 200, 1000 e 2000 ng L-1) entre 62 e 107% com desvio padrão relativo menor que 14%. Os limites de quantificação foram encontrados na faixa de ng L-1, variando entre 10 e 100 ng L-1. O método proposto foi aplicado para a determinação dos quatro filtros UV em amostras de águas naturais. This study describes the development and optimization of a solid-phase extraction (SPE) method for analysis of ultraviolet (UV) filters, benzophenone-3 (BP-3), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate (ES) and octocrylene (OC), in environmental matrices. A 25-1 fractional factorial design (FFD) was used to evaluate the significant variables for the extraction method. The optimized experimental conditions determined from the statistical evaluation were: breakthrough volume of 500 mL, eluent of ethyl acetate, wash solvent of methanol (10% in water, v/v), eluent volume of 3 × 2 mL and pH 3. The evaluated analytical parameters were satisfactory for the analytes and showed linearity between 100 and 4000 ng L-1, recoveries for four fortification levels (Method Quantification Limit, 200, 1000 and 2000 ng L-1) were between 62 and 107% with relative standard deviations less than 14%. Limits of quantification were in the ng L-1 range and were between 10 and 100 ng L-1. The proposed method was used to analyze four UV filters in natural water samples. ©2013 Sociedade Brasileira de Química.

The reliability of counting actinic keratosis

Many epidemiological studies and clinical trials have been performed concerning actinic keratoses. The most eligible endpoint in the majority of articles is counting of actinic keratoses before and after treatments, nevertheless some authors support that this is not a reliable form of evaluation. The aim of this study was to evaluate the actinic keratoses counting by various raters and suggest approaches to increase the reliability. Cross-sectional study: forty-three patients were evaluated by four raters (inter- and intra-rater assessment) on the face and forearms. The mean actinic keratoses counts on the face and forearms were 7.7 and 9.1. The overall agreement among the raters for the facial and forearm actinic keratoses was 0.74 and 0.77. The intra-rater assessment showed high rates of agreement for the face (ICC = 0.93) and forearms (ICC = 0.83). Higher agreement occurred when counting up to five lesions. Four raters led to increased measurement variability and loss of reliability. Higher rates of agreement may be achieved with small number of lesions, limitation and/or segmentation of body areas to reduce their number, in AK prevention designs, are strategies that may lead to a greater reliability of these measurements. © 2013 Springer-Verlag Berlin Heidelberg.

Development of a new method to prepare nano-/microparticles loaded with extracts of azadirachta indica, their characterization and use in controlling plutella xylostella

Biodegradable nanoparticles have been widely explored as carriers for controlled delivery of therapeutic molecules; however, studies describing the development of nanoparticles as carriers for biopesticide products are few. In this work, a new method to prepare nanoparticles loaded with neem (Azadirachta indica) extracts is presented. In this study, nanoparticles were formulated as colloidal suspension and (spray-dried) powder and characterized by evaluating pH, particle size, zeta potential, morphology, absolute recovery, and entrapment efficiency. A high-performance liquid chromatography method was used for nanoparticle characterization. The best formulations presented absolute recovery and entrapment efficiencies of approximately 100% and a release profile based on swelling and relaxation of the polymer or polymer erosion. The biological data of the formulated products against Plutella xylostella showed 100% larval mortality. The nanoparticle information improved the stability of neem products against ultraviolet radiation and increased their dispersion in the aqueous phase. © 2013 American Chemical Society.

Fish exposure to nano-TiO2 under different experimental conditions: Methodological aspects for nanoecotoxicology investigations

The ecotoxicology of nano-TiO2 has been extensively studied in recent years; however, few toxicological investigations have considered the photocatalytic properties of the substance, which can increase its toxicity to aquatic biota. The aim of this work was to evaluate the effects on fish exposed to different nano-TiO2 concentrations and illumination conditions. The interaction of these variables was investigated by observing the survival of the organisms, together with biomarkers of biochemical and genetic alterations. Fish (Piaractus mesopotamicus) were exposed for 96h to 0, 1, 10, and 100mg/L of nano-TiO2, under visible light, and visible light with ultraviolet (UV) light (22.47J/cm2/h). The following biomarkers of oxidative stress were monitored in the liver: concentrations of lipid hydroperoxide and carbonylated protein, and specific activities of superoxide dismutase, catalase, and glutathione S-transferase. Other biomarkers of physiological function were also studied: the specific activities of acid phosphatase and Na,K-ATPase were analyzed in the liver and brain, respectively, and the concentration of metallothionein was measured in the gills. In addition, micronucleus and comet assays were performed with blood as genotoxic biomarkers. Nano-TiO2 caused no mortality under any of the conditions tested, but induced sublethal effects that were influenced by illumination condition. Under both illumination conditions tested, exposure to 100mg/L showed an inhibition of acid phosphatase activity. Under visible light, there was an increase in metallothionein level in fish exposed to 1mg/L of nano-TiO2. Under UV light, protein carbonylation was reduced in groups exposed to 1 and 10mg/L, while nucleus alterations in erythrocytes were higher in fish exposed to 10mg/L. As well as improving the understanding of nano-TiO2 toxicity, the findings demonstrated the importance of considering the experimental conditions in nanoecotoxicological tests. This work provides information for the development of protocols to study substances whose toxicity is affected by illumination conditions. © 2013 Elsevier B.V..

Rietveld refinement, morphology and optical properties of (Ba 1-xSrx)MoO4 crystals

In this article, the structural refinement, morphology and optical properties of barium strontium molybdate [(Ba1-x Sr x )MoO4 with x = 0, 0.25, 0.50, 0.75 and 1] crystals, synthesized by the co-precipitation (drop-by-drop) method, are reported. The crystals obtained were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, and Fourier transform-Raman (FT-Raman) and Fourier transform-infrared (FT-IR) spectroscopies. The shapes of the crystals were observed by means of field-emission scanning electron microscopy (FE-SEM). The optical properties were investigated using ultraviolet-visible (UV-Vis) absorption spectroscopy and photoluminescence (PL) measurements. XRD patterns, Rietveld refinement, and FT-Raman and FT-IR spectra showed that all of the crystals are monophasic with a scheelite-type tetragonal structure. The refined lattice parameters and atomic positions were employed to model the [BaO8], [SrO8] and [MoO4] clusters in the tetragonal lattices. The FE-SEM images indicate that increased x content produces a decrease in the crystal size and modifications in the crystal shape. UV-Vis spectra indicated a decrease in the optical band gap with an increase in x in the (Ba1-x Sr x )MoO4 crystals. Finally, a decrease in the intensity of PL emission is apparent with an increase in x up to 0.75 in the (Ba1-x Sr x )MoO4 crystal lattice when excited by a wavelength of 350nm, probably associated with the degree of structural order-disorder. © 2013 International Union of Crystallography Printed in Singapore - all rights reserved.

Evaluation of Syngonanthus nitens (Bong.) Ruhl. extract as antifungal and in treatment of vulvovaginal candidiasis

The purpose of this study was to evaluate the in vitro anticandidal activity of a methanolic extract of Syngonanthus nitens scapes against different Candida species and clinical isolates from patients with vulvovaginal candidiasis (VVC), and its effect in vivo in the treatment of vaginal infection. Chemical characterization of the extract was performed by HPLC-UV analyses and showed the presence of flavones derivatives. The extract was effective against several Candida strains from our collection and species recovered from VVC patients, and was able to inhibit the yeast-hyphal transition. No cytotoxic activity against human female reproductive tract epithelial cells and no hemolytic activity against human red blood cells were observed. In the in vivo model of VVC, we evaluated the efficacy of the intravaginal treatment with a cream containing the extract at doses of 0.5, 1.0 and 2.0%. The treatment eradicated the vaginal fungal burden in infected rats after 8 days of treatment. S. nitens extract could be considered as an effective and non-toxic natural antifungal agent in the treatment of vulvovaginal candidiasis. © 2013 ISHAM.

Estimativa das radiações ultravioleta (UV), fotossintéticamente ativa (PAR) e infravermelha (IV) em função da razão de insolação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

'Ti''O IND.2'/'Sn''O IND. 2 modificado com 'Ag IND. 2''O', para obtenção de fotocatalisadores

Pós-graduação em Química - IQ

Indução de Acidithiobacillus ferrooxidans e seleção de linhagens mutantes para utilização na biohidrometalurgia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da concentração e recuperação de íons lantânio e neodímio por biossorção em coluna com a biomassa Sargassum sp

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Técnicas de imagem para triagem de melanoma

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

Fabricação e caracterização morfológica de filmes layer-by-layer de DODAB/FTALOCIANINA de níquel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Investigação de propriedades de filmes finos de Sn'O IND. 2' e 'Al IND. 2''O IND. 3' para aplicação em dispositivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do pH da suspensão coloidal nas propriedades de filmes finos de Sn'O IND. 2'

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