Crystalline rock outcrops in the Atlantic Forest of northeastern Brazil: Vascular flora, biological spectrum, and invasive species

We studied the vegetation of two crystalline rock outcrops in the Atlantic Forest of northeastern Brazil. We recorded typically rupicolous species, which are rare or classified as extremely endangered, such as Aechmea guainumbiorum, found exclusively in one of the study sites. In both areas there was a predominance of therophytes over other life-forms, in contrast to observations made in rock outcrops of the southern Atlantic Forest. Therophytes also stood out in other rock outcrops at similar latitudes as our study site, regardless of the surrounding vegetation. Plants of other life-forms had significantly lower richness and showed adaptations to drought, such as succulent stem, pseudobulbs, dense pilosity, and underground storage organs. Our results suggest that invasive species may modify the vegetation of crystalline rock outcrops, as they change the number of species of all life-forms in comparison between sites. Hence, our results present the biological identity of these rupicolous habitats, which are marginal to forests, and point to the need for conserving them, in order to protect the Atlantic Forest's biodiversity. © 2013 Botanical Society of Sao Paulo.

Influence of current density on crystalline structure and magnetic properties of electrodeposited Co-rich CoNiW alloys

The influence of current density, at the interval 5-100 mA cm-2, on the structural and magnetic properties of electrodeposited (Co 100-xNix)100-yWy alloys (x = 23-33.5 at. % Ni, y = 1.7-7.3 at. % W) was studied from a glycine-containing bath. W-content decreases with the increase of the current density magnitude. X-ray data have shown stabilization of hexagonal close packed, face centered cubic or a mixture of these structures by modulating the applied cathodic current density, for values lower than 50 mA cm-2. Two structural phase transitions were observed: one from hexagonal close packed to face centered cubic structural transition occurring for a current density of 20 mA cm -2, and another one, from cubic crystalline phase to amorphous state, which happens for values higher than 50 mA cm-2. These structural phase transitions seem to be associated with the W-content as well as average crystalline grain sizes that reduce with increasing the current density value. The grain size effect may explain the face centered cubic stabilization in Co-rich CoNiW alloys, which was initially assumed to be basically due to H-adsorption/incorporation. Magnetic properties of Co-rich CoNiW alloys are strongly modified by the current density value; as a result of the changes on the W-content and their structural properties© 2013 Elsevier B.V. All rights reserved.

Selenium fractionation from plasma, muscle and liver of Nile tilapia (Oreochromis niloticus)

This paper presents the results obtained from selenium fractionation in plasma, muscle and liver samples of Nile tilapia's (Oreochromis niloticus) after protein separation. The plasma, muscle and liver proteome was obtained by 2D-PAGE, and selenium in protein spots was qualitatively and quantitatively determined by synchrotron radiation X-ray fluorescence and graphite furnace atomic absorption spectrometry (GFAAS). The fluorescence spectra indicated the presence of selenium in three protein spots of plasma, two of muscle and one of liver. Selenium was found to be distributed mainly in proteins with a molar mass smaller than 57.0 kDa and with pI in the range of 5.9-9.6, with one exception in the plasma sample, which presented protein with a molar mass of 60.0 kDa. After acid mineralization of the protein spots, a GFAAS determination of the concentration of selenium bound to these proteins indicated a range of 1.35-6.82 mg per g of protein. © 2013 Springer Science+Business Media New York.

Enzymatic transesterification of soybean oil with ethanol using lipases immobilized on highly crystalline PVA microspheres

Polyvinyl alcohol (PVA) microspheres with different degree of crystallinity were used as solid supports for Rhizomucor miehei lipase immobilization, and the enzyme-PVA complexes were used as biocatalysts for the transesterification of soybean oil to fatty acid ethyl esters (FAEE). The amounts of immobilized enzyme on the polymeric supports were similar for both the amorphous microspheres (PVA4) and the high crystalline microspheres (PVA25). However, the enzymatic activity of the immobilized enzymes was depended on the crystallinity degree of the PVA microspheres: enzymes immobilized on the PVA4 microspheres have shown low enzymatic activity (6.13 U mg-1), in comparison with enzymes immobilized on the high crystalline PVA25 microspheres (149.15 U mg-1). A synergistic effect was observed for the enzyme-PVA25 complex during the transesterification reaction of soybean oil to FAEE: transesterification reactions with free enzyme with the equivalent amount of enzyme that were immobilized onto the PVA25 microspheres (5.4 U) have yielded only 20% of FAEE, reactions with the pure highly crystalline microsphere PVA25 have not yielded FAEE, however reactions with the enzyme-PVA25 complexes have yielded 66.3% of FAEE. This synergistic effect of an immobilized enzyme on a polymeric support has not been observed before for transesterification reaction of triacylglycerides into FAEE. Based on ATR-FTIR, 23Na- and 13C-NMR-MAS spectroscopic data and the interaction of the polymeric network intermolecular hydrogen bonds with the lipases residual amino acids a possible explanation for this synergistic effect is provided. © 2013 Elsevier Ltd. All rights reserved.

Microwave-hydrothermal synthesis of single-crystalline Co3O 4 spinel nanocubes

An efficient microwave-hydrothermal (MAH) method has been developed for the synthesis of highly crystalline Co3O4 spinel nanocubes via β-Co(OH)2 without any surfactant assistance. The structure and surface chemical composition along the growth process are studied. The effects as well as the merits of the MAH method on the processing and characteristics of obtained Co3O4 spinel nanocubes are highlighted. © 2013 The Royal Society of Chemistry.

Adsorsão e coeficientes de distribuição de selênio em solos do Estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Studying the distribution of Selenium in buffalo and cow's milk whey

Neste estudo, a cromatografia por exclusão de tamanho (SEC) com detecção online ultravioleta (UV), espectrometria de absorção atômica em forno de grafite (GF AAS) e a espectrometria de massa por tempo de voo com dessorção/ionização de matriz assistida por laser (MALDI-TOF-MS) foram usadas para estudar a associação de selênio com macromoléculas e compostos presentes no soro de leite de búfala e bovino. Os perfis de SEC-UV obtidos para as amostras de soro de leite de búfala e soro de leite bovino indicaram a presença de espécies de alta e baixa massa molecular. A combinação das informações obtidas com SEC-UV, GF AAS e MALDI-TOF-MS para as frações < 10 kDa confirmou a associação de selênio com espécies de baixa massa molecular.

Effect of protein, carbohydrate, lipid, and selenium levels on the performance, carcass yield, and blood changes in broilers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sources and levels of selenium on breast meat quality of broilers

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

Blood and seminal plasma concentrations of selenium, zinc and testosterone and their relationship to sperm quality and testicular biometry in domestic cats

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

Structural and optical properties of Cu2O crystalline electrodeposited films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Erythrocyte selenium concentration predicts intensive care unit and hospital mortality in patients with septic shock: a prospective observational study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A simple method based on ICP-MS for estimation of background levels of arsenic, cadmium, copper, manganese, nickel, lead, and selenium in blood of the Brazillian population

Throughout the world, biomonitoring has become the standard for assessing exposure of individuals to toxic elements as well as for responding to serious environmental public health problems. However, extensive biomonitoring surveys require rapid and simple analytical methods. Thus, a simple and high-throughput method is proposed for the determination of arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se) in blood samples by using inductively coupled plasma–mass spectrometry (ICPMS). Prior to analysis, 200 ml of blood samples was mixed with 500 ml of 10% v/v tetramethylammonium hydroxide (TMAH) solution, incubated for 10 min, and subsequently diluted to 10 ml with a solution containing 0.05% w/v ethylenediamine tetraacetic acid (EDTA) + 0.005% v/v Triton X-100. After that, samples were directly analyzed by ICP-MS (ELAN DRC II). Rhodium was selected as an internal standard with matrix-matching calibration. Method detection limits were 0.08, 0.04, 0.5, 0.09, 0.12, 0.04, and 0.1 mg//L for As, Cd, Cu, Mn, Ni, Pb, and Se, respectively. Validation data are provided based on the analysis of blood samples from the trace elements inter-\comparison program operated by the Institut National de Santé Publique du Quebec, Canada. Additional validation was provided by the analysis of human blood samples by the proposed method and by using electrothermal atomic absorption spectrometry (ETAAS). The method was subsequently applied for the estimation of background metal blood values in the Brazilian population. In general, the mean concentrations of As, Cd, Cu, Mn, Ni, Pb, and Se in blood were 1.1, 0.4, 890, 9.6, 2.1, 65.4, and 89.3 mg/L, respectively, and are in agreement with other global populations. Influences of age, gender, smoking habits, alcohol consumption, and geographical variation on the values were also considered. Smoking habits influenced the levels of Cd in blood. The levels of Cu, Mn, and Pb were significantly correlated with gender, whereas Cu and Pb were significantly correlated with age. There were also interesting differences in Mn and Se levels in the population living in the north of Brazil compared to the south.

Hematological changes and cytogenotoxicity in the tilapia Oreochromis niloticus caused by sub-chronic exposures to mercury and selenium

Fish bioassays are valuable tools that can be used to elucidate the toxicological potential of numerous substances that are present in the aquatic environment. In this study, we assessed the antagonistic action of selenium (Se) against the toxicity of mercury (Hg) in fish (Oreochromis niloticus). Six experimental groups with six fish each were defined as follows: (1) control, (2) mercury (HgCl2), (3) sodium selenite (Na2Se4O3), (4) sodium selenate (Na2Se6O4), (5) mercury + sodium selenite (HgCl2 + Na2Se4O3), and (6) mercury + sodium selenate (HgCl2 + Na2Se6O4). Hematological parameters [red blood cells (RBC), white blood cells (WBC), and erythroblasts (ERB)] in combination with cytogenotoxicity biomarkers [nuclear abnormalities (NAs) and micronuclei (MN)] were examined after three, seven, ten, and fourteen days. After 7 days of exposure, cytogenotoxic effects and increased erythroblasts caused by mercury, leukocytosis triggered by mercury + sodium selenite, leukopenia associated with sodium selenate, and anemia triggered by mercury + sodium selenate were observed. Positive correlations that were independent of time were observed between WBC and RBC, ERB and MN, and NA and MN. The results suggest that short-term exposure to chemical contaminants elicited changes in blood parameters and produced cytogenotoxic effects. Moreover, NAs are the primary manifestations of MN formation and should be included in a class characterized as NA only. Lastly, the staining techniques used can be applied to both hematological characterization and the measurement of cytogenotoxicity biomarkers.