Dynamics of the natural genesis of ß-TCP/HAp phases in postnatal fishbones towards gold standard biocomposites for bone regeneration.

The search for gold-standard materials for bone regeneration is still a challenge in reconstruction surgery. The ratio between hydroxyapatite (HAp) and ß-tricalcium phosphate (ß-TCP) in biphasic calcium phosphate ceramics (BCPs) is one of the most important factors in osteoinduction promotion and controlled biodegradability, configurating what is currently considered as a possible gold standard material for bone substitution in reconstructive surgery. Exploring the natural genesis of the HAp and ß-TCP phases in fishbones during their postnatal growth, this study developed a biphasic bioceramic obtained from the calcination of Nile tilapia (Oreochromis niloticus) bones as a function of their ages. The natural genesis dynamics of the structural evolution of the ß-TCP and HAp phases were characterized by physicochemical methods, taking into account of the age of the fish and the material processing conditions. Thermal analysis (TGA / DTA) showed complete removal of the organic matter and transitions associated with the transformation of carbonated hydroxyapatite (CDHA) to HAp and ß-TCP phases. After calcination at 900 °C, the material was characterized by: X-ray diffraction (XRD) and refinement by the Rietveld method; Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR); Raman spectroscopy; Scanning Electron Microscopy (SEM) and Flame Atomic Absorption Spectroscopy (FAAS). The analysis allowed identification and quantitative estimate of the variations of the HAp and ß-TCP phases in the formation of the BCPs. The results showed that the decrease in ß-TCP against the increase in the HAp phases is symmetrical to the dynamics of the natural genesis of these phases, surprisingly maintaining the balanced phase proportion even when bones of young fishes were used. The microstructure analysis confirms the observed transformation. In addition, in vivo tests demonstrated the osteoinductive potential of BCP scaffolds implanted in an ectopic site, and their remarkable regenerative functionality, as bone graft, was demonstrated in alveolar bone after tooth extraction. MTT cytotoxicity assay for BCP samples for MC3T3-E1 pre-osteoblasts and L929 fibroblasts cells showed viability equal or higher than 100%. A logistic empirical model is presented to explain the three stages of HAp natural formation with fish age and it is also compared to the fish size evolution.

Immune response and Raman scattering assessment in rats skin after contact with Fusarium oxysporum metabolites.

The secondary metabolites produced by Fusarium can cause disease and death when consumed and produce biological responses even in the absence of the microorganism. The IL-6, TNF-α and TGF-ß1 cytokines immune reactivity was associated with histopathological and physico-chemical changes in skin of immune competent rats after administration of Fusarium oxysporum crude extract. Rats were intradermally injected with 50 µl of 0.5 mg/ml crude extract and were euthanized at 3, 6, 12 and 24 h after injection. The inflammatory response was quantified by enzyme myeloperoxidase activity and by immunohistochemical method to detect the IL-6, TNF-α and TGF-ß1. Physico-chemical analysis was performed using FT-Raman Spectroscopy. The inflammatory response was most intense at 6 and 12 h after crude extract administration and the most significant histopathological changes were observed in the dermis. Myeloperoxidase activity was intense from 3 to 24 h after injection. The immunostaining of pro-inflammatory cytokines IL-6 and TNF-α peaked at 6 h. Immunostaining for TGF-ß1 was highest at 12 and 24 h. FT-Raman spectral analysis showed both, the most intense Fusarium interaction with the skin at 6 h, as revealed by the changes in the stretching of -CH bands (3100-2800 cm-1) in the dermis, and skin recovery trending after 12 h after crude extract injection. The results showed that secondary metabolites stimulated histopathologic changes and inflammatory responses even in the absence of the fungus, increasing myeloperoxidase activity and pro-inflammatory cytokine expression besides promoting physico-chemical changes.

Enhanced and tunable white light emission from Ag nanoclusters and Eu3+-co-doped CaBAl glasses.

Noble metal embedded glasses have been studied as promising candidates for a variety of technological applications, mainly due to their ability to enhance rare earth luminescence properties. In this work, Ag:Eu-co-doped calcium boroaluminate glasses were prepared and submitted to further heat treatment to form different Ag species. The optical and luminescence properties were investigated in terms of heat treatment times. Absorption spectra showed a successful Eu and Ag ion incorporation in the host, as well as Ag nanoparticle precipitation induced by heat treatment. Upon UV-light excitation, the co-doped glasses exhibited an intense wide emission band centered at about 500 nm, attributed to molecule-like silver species, which combined with the Eu3+ characteristic emission reaches a white light resultant emission. A new excitation band for Eu3+ at 335 nm and a silver luminescence lifetime decrease suggest an energy transfer process from molecule-like Ag to Eu3+ as being responsible for the enhanced PL properties in these glasses. An appropriate combination of a violet LED with the sample emission provides a route to achieve the ideal white light CIE color parameters. The relevant quality color results qualify these glasses as phosphors with high potential for white light emitting devices.

Broad combined orange-red emissions from Eu²âº- and Eu³âº-doped low-silica calcium aluminosilicate glass.

In this paper, a broad combined orange-red emission from Eu²âº- and Eu³âº-doped low-silica calcium aluminosilicate (LSCAS) glass is reported. Spectroscopic results demonstrate that it is possible to tune the emission wavelength by changing the excitation wavelength in the UV-Vis region. The color coordinates for the emission spectra were calculated, and using the Commission Internationale de l'Éclairage 1931 and 1976 chromatic diagrams, it is possible to note that they are dependent on the excitation wavelength. In addition, the (u', v') color coordinates for the investigated LSCAS samples are close to the Planckian spectrum in the cold region between 2000 and 2600K. Our results show that the Eu:LSCAS system can be used in a white light phosphor when mixed in aggregate with phosphors using green-yellow luminescent ions.

Angular dependence of the thermal-lens effect on LiSrAlF6 and LiSrGaF6 single crystals.

We apply thermal-lens (TL) spectrometry to measure the angular dependence of the TL effect on colquiriite single crystals. The experiments were performed with LiSrAlF(6) and LiSrGaF(6) using a two-beam mode-mismatched configuration. The results show that it is possible to minimize the TL effect by selecting the appropriate crystal orientation. Our data also show that the anisotropy of the linear thermal expansion coefficient drives the amplitude of the TL effect, including the inversion from focusing to defocusing as the crystal orientation angle tends to the c-axis direction. The results may be useful for those working to develop a high-power laser using LiSrAlF(6)(:Cr) and LiSrGaF(6)(:Cr) single crystals, allowing for optimization of the designed laser cavity.

Percutaneous penetration, melanin activation and toxicity evaluation of a phytotherapic formulation for vitiligo therapeutic.

The aim of this work was to apply photoacoustic spectroscopy for the ex vivo determination of the penetration rate of a phytotherapic formulation for vitiligo therapeutic, with or without salicylic acid as the promoter agent. In addition, the compound toxicity and morphophysiology effects were evaluated for different concentrations of salicylic acid. The experiments were performed as a function of the period of time of treatment in a well-controlled group of rabbits. Toxic effects were not observed with any of the tested products. All formulations containing salicylic acid induced cutaneous reaction which was dose dependent. The histological analysis showed that the use of the medication was associated with an increased comedogenic effect in relation to the control group, regardless of salicylic acid concentration. Inflammatory reactions and acanthosis were observed only in the animals treated with formulations containing higher concentrations of salicylic acid, while none of these effects were detected with the use of the formulation containing 2.5% (wt/vol) of salicylic acid. Photoacoustic depth monitoring showed that both formulations, with or without salicylic acid, propagated through the skin up to the melanocytes region, suggesting that the transport of the active agent may occur through the epithelial structure without the need of using queratinolitic substances, which are known to induce side effects in the animals.

Thermal characterization in vitro of human nail: photoacoustic study of the aging process.

In the present work, the rear photoacoustic signal technique is used to determine thermal properties of human nails. The aging process of the human nail is analyzed through its thermal diffusivity and specific heat and using these results, thermal conductivity and thermal effusivity is determined. The study in vitro of this natural polymer showed a minimum for thermal properties to age about 20 years and an increase and possible saturation of them for ages over 50 years. The minimum value found for thermal diffusivity was close to 10x10(-4) cm2 s(-1) with saturation near 18x10(-4) cm2 s(-1). Thermal conductivity and effusivity presents the same behavior.

Hipertensäo arterial na zona rural / Arterial hypertension in country

Em razäo da escassez na literatura de dados referentes à hipertensäo arterial na zona rural do Brasil, esta pesquisa foi realizada. A pressäo arterial de quatro diferentes populaçöes da zona rural de Alfenas - MG- foi determinada pelo método auscultatório, na residência dos voluntários ou em locais indicados pelos represntantes das comunidades, após repouso de cinco minutos. Uma vez constatada hipertensäo arterial, novas medidas foram feitas em intervalos de 5 a 15 minutos, inicialmente, cada participante da pesquisa respondia um questionário no qual constavam perguntas relacionadas aos fatores de risco da hipertensäo arterial. Os resultados mostram um alto índice de hipertensäo na zona rural pesquisada 47,43 porcento, tendo sido atribuído a elevada média de idade dos participantes, a falta de assistência médica e de programas de prevençäo da pressäo arterial, a influência genética, a dieta rica em gorduras e a ansiedade ou estresse. O número de mulheres hipertensas foi superior ao de homens, possivelmente devido à maior incidência de hipertensäo arterial nas mulheres após a menopausa. Conclui-se que vários fatores, em conjunto ou separadamente, podem ter atribuido para se encontrar na zona rural pesquisada um índice elevado de hipertensäo arterial ÿ(au)