Determinação de bromo e iodo em alga marinha comestível por ICP-MS após decomposição por combustão iniciada por micro-ondas

A method based on microwave-induced combustion (MIC) was applied for the decomposition of different types of edible seaweed (Nori, Hijiki and Wakame) for subsequent determination of bromine and iodine by inductively coupled plasma mass spectrometry (ICP-MS). Decomposition of 500 mg of each sample was achieved in less than 30 min. A single and diluted solution (150 mmol L-1 (NH4)2CO3) was used for the absorption of both analytes and a reflux step of 5 min was applied to improve analyte recoveries. Accuracy was evaluated using certified reference materials and agreement was between 103 and 108% for both elements.

CARACTERIZAÇÃO E ATIVIDADE CATALÍTICA DE K2CO3/AL2O3 NA TRANSESTERIFICAÇÃO DO ÓLEO DE GIRASSOL COM AQUECIMENTO CONVENCIONAL E MICRO-ONDAS

Commercial and synthetic mesoporous aluminas impregnated with potassium carbonate were characterized by X-ray diffraction (XRD), nitrogen physisorption, infrared spectroscopy and 27Al MAS NMR. The activities in the transesterification reaction of sunflower oil with methanol for biodiesel production were evaluated. 27Al MAS NMR spectra evidenced the presence of AlIV and AlVI in the samples, and also of AlV sites in the mesoporous synthesized alumina, which disappeared after impregnation with potassium salt followed by calcination. All aluminas containing potassium were active for biodiesel production from sunflower seed oil, with high conversions by both conventional heating and microwave irradiation.

DESENVOLVIMENTO DE MATERIAIS HÍBRIDOS MICRO-MESOPOROSOS DO TIPO ZSM-12/MCM-41

Micro-mesoporous hybrid materials of ZSM-12/MCM-41 type with different micro- and mesoporosity contributions were prepared by a procedure that uses the desilication of the zeolite in an alkaline medium, followed by recrystallization onto the mesostructure, where the zeolite is used as the silica source in the formation of mesoporous phase. The materials were characterized by X-ray diffraction, nitrogen adsorption-desorption at 77 K, scanning electron microscopy and thermal analysis. The results showed that the methodology utilized is efficient for obtaining hybrid materials of ZSM-12/MCM-41 type with optimized micro-and mesoporosity.

PRODUÇÃO DE BIODIESEL A PARTIR DE ÁCIDOS GRAXOS PROVENIENTES DO REFINO DE ÓLEOS VEGETAIS VIA CATÁLISE ÁCIDA HETEROGENEA E MICRO-ONDAS

This work presents the biofuel production results of the esterification of fatty acids (C12-C18) and high-acid-content waste vegetable oils from different soap stocks (soybean, palm, and coconut) with methanol, ethanol, and butanol by acid catalysis. We used Amberlyst-35 (A35) sulfonic resin as a heterogeneous acid catalyst and p-toluenesulfonic acid as a homogeneous catalyst for comparison. Both the heterogeneous (A35) and homogeneous (p-toluenesulfonic acid) reactions were performed with 5% w/w of catalyst. The final products were analyzed by proton nuclear magnetic resonance (1H NMR). The homogeneous catalyzed esterification of fatty acids with methanol, ethanol, and butanol produced esters with yields higher than 90%. In the reaction with fatty acids and methanol catalyzed by A35, the best results were achieved with lauric acid and methanol, with a yield of 97%. An increase in the hydrocarbon chain decreased the rate of conversion and yield for stearic acid with methanol, which was 90%. Maximum biodiesel production was achieved from coconut and soybean soap stocks and methanol (96%-98%), which showed conversions very close to those obtained from their respective fatty acids. Microwave irradiation reduced the reaction time from 6 to 1 h in the esterification reaction of fatty acids with butanol.

Comportamento fotofísico do antraceno em sistemas micro-heterogêneos argila-surfactantes-íons metálicos

Argilas constituem uma classe de complexos micro-heterogêneos e podem ser utilizados como substrato para adsorção. O seu comportamento de sorção em fase sólida intensificada pela presença de surfactantes, argilas organofílicas, é um importante fenômeno explorado pela tecnologia ambiental para a remoção de compostos orgânicos policíclicos (hidrocarbonetos aromáticos policíclicos, HPA) da água, introduzidos no ambiente por fontes antropogênicas. Este trabalho tem por objetivo estudar o comportamento fotofísico do antraceno, como modelo de HPA, em sistemas micro-heterogêneos argila-surfactantes-íons metálicos (M(II)= Cd(II), Cu(II), Hg(II), Ni(II) e Pb(II); surfactantes: CTACl; SDS; TR-X100). Os estudos foram conduzidos pelo monitoramento na mudança das propriedades de fluorescência estática e na supressão da emissão do antraceno utilizado como sonda fluorescente. Como supressores foram utilizados os cátions metálicos: Cd(II), Cu(II), Hg(II), Ni(II) e Pb(II). O perfil do espectro de fluorescência e os resultados dos ensaios de supressão da fluorescência da sonda permitiram inferir na localização do sítio de solubilização do antraceno nos sistemas micro-heterogêneos estudados e na conseqüente organização dos mesmos.

Relative reduction in annual soil loss in micro watersheds due to the relief and forest cover

With the intense debate, in Brazil, between landowners and public agencies about the amount of area with forest cover needed in different regions, there is an increase of the need for provision of technical data used as a basis for decision making. One of the criteria to evaluate the effect of forest cover in protecting water resources is the soil loss, which leads to several consequences on the environment, including the silting of the rivers. Therefore, this study aimed to evaluate the reduction in the soil loss in micro watersheds with different reliefs, size and location of forest cover, in the Corumbataí River watershed, in the state of São Paulo, using the Revised Universal Soil Loss Equation (RUSLE) in a GIS environment. For this study, 18 watersheds in three degrees of slope were selected, and 20 scenarios for land-use were established, by analyzing the influence of the PPA size, and the size and the location of the Legal Reserve. The results showed that: a) the effect of forest cover in reducing annual soil loss varies depending on the average slope of the watershed; b) the PPA width must be determined taking into account the slope of the watershed; c) the Legal Reserve must be located along the PPA. These provide better results in reducing annual soil loss.

Variação da força de resistência à micro-tração de fragmentos de ossos corticais preservados em diversos meios e a fresco: estudo experimental em coelhos

Devido ao crescente uso dos aloenxertos nas cirurgias ortopédicas, há a necessidade do conhecimento de suas características biomecânicas ao longo do tempo de preservação. O presente trabalho consistiu na análise da força de resistência à micro-tração de amostras de ossos corticais de coelho preservadas em diversos meios por até 180 dias e a fresco. Os resultados revelaram que a resistência e o tempo de preservação apresentaram uma relação inversamente proporcional, significando que, quanto maior o tempo de preservação, menor a resistência física avaliada no ensaio biomecânico de resistência à micro-tração. Dos meios utilizados, a glicerina apresentou menores valores quanto ao teste de resistência, demonstrando, após 30 dias de preservação, apenas 24,58% da força presente no osso a fresco e, aos 180 dias, 1,76%. As amostras submetidas à autoclavagem também demonstraram baixos valores ao final do experimento, quando permaneceram com apenas 12,31% da força presente no osso a fresco. Os ossos preservados em plasma homólogo, líquido de dakin e aqueles criopreservados apresentaram os melhores índices de resistência ao final do experimento, permanecendo, respectivamente, com 82,47; 70,34 e 66,72% da força máxima quando comparados com a resistência dos ossos frescos. Concluiu-se que a escolha do método e o tempo de preservação interferiu diretamente na biomecânica dos ossos corticais, promovendo a diminuição da capacidade de resistência à tração ao longo do período de preservação.

Occurrence of parasitism by Dioctophyma renale in ring-tailed coatis (Nasua nasua) of the Tiete Ecological Park, São Paulo, Brazil

Dioctophymosis is a worldwide renal parasitosis caused by the Dioctophyma renale nematode, which results in progressive destruction of renal tissue. Aquatics annelids are considered the main intermediate hosts and the literature refers as permanent hosts of dogs, wild mammals and even humans. During procedures for population control of coatis (Nasua nasua) in the Ecological Park of Tietê (PET), was noticed the presence of parasitosis by D. renale. From 68 animals, males and females, young and adults, submitted to exploratory laparotomy, 51 were positive for the presence of worms, 9 were found only in the right kidney. In 10 cases, in addition to right kidney parasitism, worms were also observed in the abdominal cavity. In 24 cases D. renale was found only in the abdominal cavity and in 8 animals the right kidney was reduced to a small rigid structure. The study showed that the preferred site for parasitism of the worm, considered erratic, was the abdominal cavity in 66.66% of the cases.

Neoformação óssea e osteointegração de biomateriais micro e nanoestruturados em ovinos

A substituição de parte do tecido ósseo se faz necessária muitas vezes na rotina cirúrgica, seja em função de fraturas, neoplasias ósseas ou enfermidades ortopédicas que acarretem em perda óssea. Neste sentido, têm se buscado biomateriais capazes de promover esta substituição, evitando o uso de enxertos ou transplantes ósseos. O objetivo deste trabalho foi avaliar a capacidade osteoregenerativa de biomateriais em diferentes composições, em tíbias de ovinos. Foram utilizadas oito ovelhas mestiças texel, com 12 meses de idade e peso médio de 28,5±7,4kg. Após adequada preparação anestésica e cirúrgica, foram produzidos três defeitos ósseos na diáfise das tíbias em sua face medial, totalizando seis defeitos de 6mm cada, sendo que quatro foram preenchidos por biomateriais, e dois por fragmentos ósseos retirados do próprio animal (autocontrole). Os materiais implantados foram: hidroxiapatita (HA), tricálcio fosfato-β (TCP-β), hidroxiapatita/tricálcio fosfato-b 60/40 (HA/TCP-b 60/40) e o nanocompósito hidroxiapatita/alumina a 5% (HA/Al2O3 a 5%). Os animais foram alocados em dois grupos: Grupo 60 (n=04), em que os animais foram eutanasiados após 60 dias da colocação dos implantes e Grupo 90 (n=04), em que a eutanásia ocorreu 90 dias após a colocação dos implantes. Foram realizadas radiografias nos períodos pré-operatório, imediatamente após o procedimento e aos 30, 60 e 90 dias de pós-operatório, a fim de excluir qualquer alteração prévia ou complicação pós-operatória, capaz de comprometer o estudo. Após a eutanásia, foram coletadas as tíbias para avaliação macro e microscópica, por meio de microscopia eletrônica de varredura (MEV) e microscopia óptica. Os resultados encontrados mostraram uma boa capacidade de neoformação óssea e uma lenta absorção da HA. O TCP-β foi rapidamente absorvido e apresentou boa capacidade osteoindutiva e osteocondutiva, sendo observada neoformação óssea no interior dos grânulos deste biomaterial. O composto bifásico HA/TCP-β (60/40) apresentou o melhor resultado a longo prazo, devido ao melhor controle na solubilização e liberação dos íons cálcio e fosfatos para o meio biológico durante o processo de neoformação óssea. O biomaterial nanocompósito HA/Al2O3 a 5% não apresentou resultados promissores neste estudo, e sugerem-se novas pesquisas a fim de investigar melhor o potencial e aplicabilidade deste novo biomaterial. Conclui-se que a hidroxiapatita, o tricálcio fosfato-β e a associação HA/TCP-β (60/40) apresentam excelente capacidade de reparação óssea, podendo ser utilizados como substitutos ósseos; a associação HA/TCP-β (60/40) é o melhor dentre os biomateriais estudados, pois apresenta velocidade de absorção intermediária em relação à HA e ao TCP-β isolados, fornecendo ainda uma sustentação adequada ao tecido neoformado; o biomaterial HA/Al2O3 5% se mostrou incompatível, provocando reação de rejeição por parte do hospedeiro e com insignificante formação de tecido ósseo, sugerindo novas pesquisas acerca deste material.

Non-linear analysis of laminated metal matrix composites by an integrated micro/macro-mechanical model

The present paper describes an integrated micro/macro mechanical study of the elastic-viscoplastic behavior of unidirectional metal matrix composites (MMC). The micromechanical analysis of the elastic moduli is based on the Composites Cylinder Assemblage model (CCA) with comparisons also draw with a Representative Unit Cell (RUC) technique. These "homogenization" techniques are later incorporated into the Vanishing Fiber Diameter (VFD) model and a new formulation is proposed. The concept of a smeared element procedure is employed in conjunction with two different versions of the Bodner and Partom elastic-viscoplastic constitutive model for the associated macroscopic analysis. The formulations developed are also compared against experimental and analytical results available in the literature.

Ring Dark Solitons in Toroidal Bose-Einstein Condensates

In this Thesis, we study various aspects of ring dark solitons (RDSs) in quasi-two-dimensional toroidally trapped Bose-Einstein condensates, focussing on atomic realisations thereof. Unlike the well-known planar dark solitons, exact analytic expressions for RDSs are not known. We address this problem by presenting exact localized soliton-like solutions to the radial Gross-Pitaevskii equation. To date, RDSs have not been experimentally observed in cold atomic gases, either. To this end, we propose two protocols for their creation in experiments. It is also currently well known that in dimensions higher than one, (ring) dark solitons are susceptible, in general, to an irreversible decay into vortex-antivortex pairs through the snake instability. We show that the snake instability is caused by an unbalanced quantum pressure across the soliton's notch, linking the instability to the Bogoliubov-de Gennes spectrum. In particular, if the angular symmetry is maintained (or the toroidal trapping is restrictive enough), we show that the RDS is stable (long-lived with a lifetime of order seconds) in two dimensions. Furthermore, when the decay does take place, we show that the snake instability can in fact be reversible, and predict a previously unknown revival phenomenon for the original (many-)RDS system: the soliton structure is recovered and all the point-phase singularities (i.e. vortices) disappear. Eventually, however, the decay leads to an example of quantum turbulence; a quantum example of the laminar-to-turbulent type of transition.

Micro Data Repositories: Increasing the Value of Research on the Web

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Protein dynamics: hydration and cavities

The temperature-pressure behavior of proteins seems to be unique among the biological macromolecules. Thermodynamic as well as kinetic data show the typical elliptical stability diagram. This may be extended by assuming that the unfolded state gives rise to volume and enthalpy-driven liquid-liquid transitions. A molecular interpretation follows from the temperature and the pressure dependence of the hydration and cavities. We suggest that positron annihilation spectroscopy can provide additional quantitative evidence for the contributions of cavities to the dynamics of proteins. Only mature amyloid fibrils that form from unfolded proteins are very resistant to pressure treatment.

Indole ring oxidation by activated leukocytes prevents the production of hypochlorous acid

Hypochlorous acid (HOCl) released by activated leukocytes has been implicated in the tissue damage that characterizes chronic inflammatory diseases. In this investigation, 14 indole derivatives, including metabolites such as melatonin, tryptophan and indole-3-acetic acid, were screened for their ability to inhibit the generation of this endogenous oxidant by stimulated leukocytes. The release of HOCl was measured by the production of taurine-chloramine when the leukocytes (2 x 10(6) cells/mL) were incubated at 37ºC in 10 mM phosphate-buffered saline, pH 7.4, for 30 min with 5 mM taurine and stimulated with 100 nM phorbol-12-myristate acetate. Irrespective of the group substituted in the indole ring, all the compounds tested including indole, 2-methylindole, 3-methylindole, 2,3-dimethylindole, 2,5-dimethylindole, 2-phenylindole, 5-methoxyindole, 6-methoxyindole, 5-methoxy-2-methylindole, melatonin, tryptophan, indole-3-acetic acid, 5-methoxy-2-methyl-3-indole-acetic acid, and indomethacin (10 µM) inhibited the chlorinating activity of myeloperoxidase (MPO) in the 23-72% range. The compounds 3-methylindole and indole-3-acetic acid were chosen as representative of indole derivatives in a dose-response study using purified MPO. The IC50 obtained were 0.10 ± 0.03 and 5.0 ± 1.0 µM (N = 13), respectively. These compounds did not affect the peroxidation activity of MPO or the production of superoxide anion by stimulated leukocytes. By following the spectral change of MPO during the enzyme turnover, the inhibition of HOCl production can be explained on the basis of the accumulation of the redox form compound-II (MPO-II), which is an inactive chlorinating species. These results show that indole derivatives are effective and selective inhibitors of MPO-chlorinating activity.