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Item Impact of microaeration bioreactor on dissolved sulfide and methane removal from real UASB effluent for sewage treatment.(202) Souza, Cássia Cabral e; Sanson, Ananda Lima; Afonso, Robson José de Cássia Franco; Chernicharo, Carlos Augusto de Lemos; Araújo, Juliana Calábria deTwo bioreactors were investigated as an alternative for the post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor treating domestic sewage, aiming at dissolved sulfide and methane removal. The bioreactors (R-control and R-air) were operated at different hydraulic retention times (HRT; 6 and 3 h) with or without aeration. Large sulfide and methane removal efficiencies were achieved by the microaerated reactor at HRT of 6 h. At this HRT, sulfide removal efficiencies were equal to 61% and 79%, and methane removal efficiencies were 31% and 55% for R-control and R-air, respectively. At an HRT of 3 h, sulfide removal efficiencies were 22% (R-control) and 33% (R-air) and methane removal did not occur. The complete oxidation of sulfide, with sulfate formation, prevailed in both phases and bioreactors. However, elemental sulfur formation was more predominant at an HRT of 6 h than at an HRT of 3 h. Taken together, the results show that post-treatment improved the anaerobic effluent quality in terms of chemical oxygen demand and solids removal. However, ammoniacal nitrogen was not removed due to either the low concentration of air provided or the absence of microorganisms involved in the nitrogen cycle.Item Xanthones from Kielmeyera rubriflora.(1971) Gottlieb, Otto Richard; Mesquita, Antônio Augusto Lins; Nagem, Tanus JorgeKielmeyera rubriflora Camb. contains 2_hydroxyxanthone, 2,4-dimethoxy-3-hydroxyxanthone, 2,3-dimethoxy-4_hydroxyxanthone, 4-hydroxy-2,3-methylenedioxyxanthone, 4-methoxy-2,3-methylenedioxyxanthone and 1,7-dimethoxy-2,3,&trihydroxyxanthone (Ia).Item American trypanosomiasis (chagas' disease) in conventional and germfree rats and mice.(1987) Silva, Marcelo Eustáquio; Evangelista, Elísio Alberto; Nicoli, Jacques Robert; Bambirra, Eduardo Alves; Vieira, Enio CarlosItem Influence of experimental illumination and seasonal variation on crossbreeding matinf in the snail Biomphalaria glabrata.(1988) Souza, Fernando Pimentel; Schall, Virgínia Torres; Barbosa, Norma Dulce de Campos; Souza, Mauro Schettino de; Lautner Júnior, RodolfoThe crossbreeding activities of the Schistosoma mansoni vector snail Biomphalaria glabrata were counted in a laboratory aquarium throughout the year under two regimes of 12h light: 12h dark from 7 A., M. to 10 P. M. Mating increased significantly in Authmn and Winter and just missed a significant inverse correlation with temperature and a direct one with locomotion. Other similar experiments were carried out to compare mating under various ilumination conditions in complete daily cycle measurements. Mating counts decreased under the regimes which submited snail to a total exposure of 12h light and 12 dark during a daily cycle in the following sequence: 12h light: 12h dark alternating hourly with light gradient, 12h light: 12h dark, 1h light: 1h dark and 12h dark: 12h light. Under two constant illuminations, the mating scored less than under the previous conditions, except under 12h light. Under darkeness the mating count was lower than light conditions. There was no way to differentiate the night and day rhythms of mating on different days in each regime, except for mating under 12h light: 12 dark alternating with light gradient, constant dark and 12h dark: 12h light conditions. Mating increased in certain light and temperature conditions, in wich the intensities, should have an optimum value.Item Pharmacokinetic aspects of ter-butylaminoethyl dissulfide, an experimental drug against schistosomiasis in mice.(1989) Andrade, Milton Hércules Guerra de; Freire, Antonio Carlos Teixeira; Nelson, David LeeItem Pharmacokinetic profile of tert-butylaminoethanetiol.(1990) Andrade, Milton Hércules Guerra de; Freire, Antonio Carlos Teixeira; Nelson, David LeeItem Synthesis and X-ray crystal structure of the [Ni(HDPE)2][NO3]2.2H2O.(1991) Levy, Noel Massinhan; Neves, Ademir; Franco, César Vitorio; Cota, André Barros; Castellano, Eduardo Ernesto; Mascarenhas, Yvone PrimeranoItem Mössbauer and X-ray diffraction studies of the Morin transition in tabular hematites.(1991) Costa, Geraldo Magela da; Silva, E. Galvão da; Jesus Filho, M. F. deSeveral synthetic hematites have been analysed by X-ray diffraction and M~Sssbauer spectroscopy. They have tabular shape and their Morin transition at 85 K show a dependence on the ratio (R) of the sizes in c and a directions. The Morin transition has been observed for samples with R = 0.43 _+ 0.05.Item Mössbauer study of rock paintings from Minas Gerais, Brazil.(1991) Costa, Geraldo Magela da; Souza, Luiz Antonio Cruz; Jesus Filho, M. F. deFour samples of a wall containing rock paintings have been studied by M(:,ssbauer spectroscopy in combination with optical microscopy analysis and X-ray diffraction. Hematite and goethite were identified as the pigments responsible for the colors and the mineral tinsleyite, as the principal component of a light pink layer that is present in some parts of the wall.Item Evidence for a new phase in the Domany-Kinzel cellular automaton.(1991) Martins, M. L.; Resende, Hélio Fernando Verona de; Tsallis, Constantino; Magalhães, A. C. N. deWe consider a generalized version (including anisotropy) of the stochastic one-dimensional cellular automaton studied by Domany and Kinzel. It recovers Wolfram-like deterministic cellular automata as particular cases. The phase diagram presents three (and not two, as previously suggested) phases which were detected through the numerical study of both the order parameter and the sensitivity to initial conditions. The various universality classes are exhibited as well.Item Relation between the oxidation growth rate of chromia scales and self-diffusion in Cr203.(1992) Sabioni, Antônio Claret Soares; Huntz, Anne Marie; Philibert, J.; Lesage, B.In most cases, chromia scales are assumed to grow by predominant chromium diffusion. However, results of Atkinson and Taylor indicated that chromium bulk diffusion could not account for the growth rate of chromia scales. Moreover, recent results of Park et aL showed that oxygen diffusion in chromia was faster than chromium diffusion. So, at this date, the controlling process of the growth of chromia scales is not elucidated. To interpret such a phenomenon, oxygen and chromium self-diffusion coefficients in Cr203 single crystals and polycrystals were determined in the same materials and in the same experimental conditions, thus allowing a direct comparison. Tracers were introduced by ion implantation, thick film methods, and isotopic exchange, using the 54Cr, ~~ and 180 isotopes. Depth profiling was made by secondary ion mass spectroscopy (SIMS). The bulk diffusion coefficients were computed by using a general solution of the Fick's law taking into account evaporation and exchange at the surface. Grain-boundary diffusion coefficients were computed by using the Whipple-Le Claire equation for type B intergranular diffusion. Lattice and grain boundary self-diffusien coefficients were determined as a function of temperature and oxygen pressure. The diffusion coefficients are lower than results given in the literature and do not depend on the oxygen pressure. Moreover, it is found that oxygen diffusion is faster than chromium diffusion. These results are compared to the oxidation constants of chromia-forming alloys and it is shown that neither lattice self-diffusion, nor grain-boundary self-diffusion can justify the growth rate of chromia scales. Such a situation is compared to NiO case, for which authors found important differences in grain-boundary diffusivity, according to the elaboration mode of NiO (thermal oxidation or growth from the melt).Item X-ray differential line broadening on tabular haematites.(1992) Costa, Geraldo Magela da; Jesus Filho, M. F. deThe haematites obtained by dehydration of three synthetic goethites of different sizes have been characterized by X-ray diffraction, M6ssbauer spectroscopy and transmission electron microscopy. The transformation itself has been studied by thermogravimetric analysis and differential scanning calorimetry. Samples (24) obtained by annealing the goethites for 30 min at several temperatures up to 900 ~ were analysed. All samples had a tabular shape. The variation of the internal magnetic field, as well as of the line widths of the spectra at room temperature, indicate growth of the particle size. The constant value for the quadrupole splitting and the absence of a distribution of hyperfine interactions of the spectra at 80 K excluded the presence of iron ions out of their normal positions. No strain was detected by Xray diffraction. The results also showed a differential line broadening in the haematite pattern, but there was no shift in the position of the lines. This broadening was present in all lines, including those wih /= 3n (n = 0,1,2 .... ). Increasing the treatment temperature made all lines sharp. The relative integrated intensities, /(1 1 0)//(1 04), of each series remained unaltered, but the relative intensities did not. The above results lead to the conclusion that the differential Xray line broadening of haematites derived from goethite occurs only in tabular (or acicular) haematites with small size. For small spherical particles, the broadening should be uniform for all lines.Item Synthesis and characterization of lanthanide trifluoroacetate complexes with 3-picoline-N-oxide.(1992) Zinner, Léa Barbieri; Carvalho, Carlos Alberto Alves de; Zinner, KlausComplexes with composition Ln(F3C-COO)3•2(3-picNO)•ξH2O were synthesized. According to X-ray powder patterns and IR data five series of isomorphous compounds were detected: LaNd; SmEu; Gd>Tm, Y; Ho, Er, Tb; Dy, Yb, Lu. They behave as nonelectrolytes in methanol. IR spectra show a shift of νNO to lower frequencies, as compared with the free ligand, as a result of coordination through the oxygen. The bands attributed to the anions indicate two modes of coordination. The neodymium spectrum at 77 K shows that the central ion is not involved in a cubic site. Electrostatic bonds between Nd3+ and ligands were evidenced by the nephelauxetic, Sinha's parameters and covalent factor from the room temperature spectrum. Using the electronic emission spectrum, at 77 K, it was possible to conclude that europium ions present two different symmetry sites, since a splitting of the 5D0 → 7F9 band was observed. The complex species are probably polymeric or at least dimeric, and europium ions are involved in two different sites, but with the same C3ν symmetry.Item Study of oxygen self-diffusion in oxides by ion beam techniques : comparison between nuclear reaction analysis and SIMS.(1993) Sabioni, Antônio Claret Soares; Freire Júnior, Fernando Lázaro; Leite Filho, Carlos Vieira Barros; Amami, B. A.; Dolin, C.; Monty, C.; Millot, F.Oxygen self-diffusion in Fe,_,0 single crystals has been studied by means of the isotope exchange method in Hz/Hz”0 atmospheres. The ‘*O concentration profiles were determined by using two different techniques based on ion beams: secondary ion mass spectrometry (SIMS) and nuclear reaction analysis (NRA); the latter by means of the narrow nuclear resonance reaction ‘“O(p, o)“N at 629 keV, r = 2.1 keV. The diffusion coefficients obtained from the analysis of the measured profiles are in good agreement with those found in the literature. To compare the depth resolution and sensitivity of both techniques, the “0 profiles of implanted Cr,O, single crystals (Erso = 50 keV, fluence = 1.6 X lOI ions/cm’) were also measured.Item Positronium formation and inhibition in binary solid solutions on Al (III) and Co (III) tris (acetylacetonates).(1993) Machado, José Caetano; Carvalho, Cornélio de Freitas; Magalhães, Welington Ferreira de; Netto, Antonio Marques; Abbé, J. Ch.; Duplâtre, G.Positron annihilation lifetime spectroscopy has been applied in mixtures and in solutions of solid Al(W), Al(acac),, and Co(III), Co(acac)g, tris(acetylacetonates). For the solid solutions of Co(acac), in Al(a~+c)~, a strong inhibition of positronium formation is observed with increasing cobalt complex concentration, while there is no quenching of the positronium lifetime. In the solid mixtures the positronium formation probability decreases linearly with Co(acac)g concentration, while the positronium lifetime remains constant. The free volume model appears inadequate to explain the experimental results which are satisfactorily understood on the basis of the spur model.Item Tyrosine 151 is part of the substrate activation binding site of bovine trypsin.(1993) Oliveira, Maria Goreti de Almeida; Rogana, Edyr; Rosa, José César; Reinhold, Bruce B.; Andrade, Milton Hércules Guerra de; Greene, Lewis Joel; Guia, Marcos Luíz dos MaresIdentification of the substrate activation site of p-trypsin by a 1:l reacwtiotnh p-diazoniumbenzamidine chloride was confirmebdy spectral anaylsisP. roteolysis of Cm-p-benzamidino-azo-@-trypsipnr ovided peptides containing modified tyrosine residues. The major product, Ser-146 to Lys-156, which corresponded to labeling at '&r-151, was recovereidn 35%y ield, and its structure was demonstrated by amino acid analysis, Edman deg radation, and mass spectrometry. Yielodfs labeled Tyr- 151, Tyr-39, and Tyr-172,i dentified by peptide analysis, were in the proportion of 100:7:3. Tyr-l51-(p-benzamidinol- azo-j3-trypsinis permanently activated, but can be further activated by substrates. Values of kcat, Ks', and kc,,. vary from twot o three times the equivalent values for trypsin. Berenil (4,4'-diazoamino-bis-benzamidine), a parabolic competitive inhibitoorf ptrypsin, was ah yperbolic competitive inhibitor of azo-p-trypsin. Thus, Tyr-151, part of subsite 5'2, affects the catalytic process and, when modified covalently, permanently activates trypsin. Equilibrium bindinwgi th berenil supportedt he kinetic data obtainedw ith substrates. This permitst he integration of protein modification, kinetics, equilibrium binding, and crystallographic datao demonstrate a fine interaction between subsites S1-S3 and5 '2 in trypsin and azo-p-trypsin, resulting in subtle structural changes when the native enzyme is covalently modified at Qr-151.Item Cation self-diffusion in (Th-5%U)O2.(1993) Sabioni, Antônio Claret Soares; Lameiras, Fernando Soares; Cardoso, Paulo EdsonItem Positron annihilation studies in binary solid solutions of metal betadiketonates, using lifetime and doppler broadening spectroscopies.(1993) Machado, José Caetano; Porto, Arilza de Oliveira; Carvalho, Cornélio de Freitas; Magalhães, Welington Ferreira de; Netto, Antônio MarquesPositron annihilation lifetime (LS) and Doppler broadening annihilation kadiation lineshape (DBARL) spectroscopies measurements were performed in several binary solid solutions of the general formula M(l-x,Gfx,L,3 where M = Al(II1) , Ga(II1) , or In(II1) , as matrix; G = Cr (111) , Mn (111) , Fe (111) , co (111) , Ru (111) , Rh(III), and Ir(III), as guest molecules, L = acetylacetone (acac) or dipivaloylmethane (dpm), and X = guest molecule mole fraction. The studied systems can be classified in two groups: the first one presenting only inhibition of positronium formation and the second one presenting inhibition and quenching effects. The inhibition and quenching constants were determined.Item Infection with Leishmania major induces interleukin-12 production in vivo.(1994) Vieira, Leda Quercia; Hondowicz, Brian D.; Afonso, Luís Carlos Crocco; Wysocka, Maria; Trinchieri, Giorgio; Scott, PhillipExperimental infections of mice with the protozoan parasite Leishmania major provide an excellent model for defining the conditions required for generation of CD4 ÷ Thl and Th2 cells in vivo. Since interleukin-12 (IL-12) has been implicated in the development of Thl cells, we investigated whether L. major stimulates IL-12 production in vitro or in vivo. Surprisingly, macrophages cultured in vitro failed to produce IL-12 following L. major infection. In contrast, lymph node cells from C3H mice infected for 2 days with L. major produced elevated levels of IL-12. In order to determine if the inability to stimulate IL-12 production was limited to in vitro infections, we infected macrophages in vivo by inoculating L. major into the peritoneal cavity. Peritoneal cells isolated 24 h later exhibited a significant increase in the number of cells producing IL-12. In addition, supernatants harvested from these cells following culture contained elevated levels of IL-12. These data indicate that L. major infection induces increased IL-12 production in mice.Item The center shift in the Mössbauer spectra of maghemite and aluminum maghemites.(1994) Costa, Geraldo Magela da; Grave, Eddy De; Bowen, L. H.; Vandenberghe, Robert Emile; Bakker, P. M. A. deSynthetic, relatively well-crystallized aluminum-substituted maghemite samples, y-(Aly. Fe~_y)203, with y = 0, 0.032, 0.058, 0.084, 0.106 and 0.151 have been studied by X-ray diffraction and zero-field Mrssbauer spectroscopy in the range 8 K to 475 K, and also with an external field of 60 kOe at 4.2 K and 275 K. It was found that there are two different converging models for fitting the zero-field spectra of the maghemites with a superposition of two Lorentzian-shaped sextets, both resulting in inconsistent values for the hyperfine fields (Hhf) and/or the center shifts (6) of the tetrahedral (A) and octahedral (B) ferric ions. From the applied-field measurements it is concluded that there is a constant difference of 0.12 _+ 0.01 mm/s between 6B and 6A, regardless of the A1 content. For the Al-free sample the center shifts are found as: 64 = 0.370 mm/s and 6a = 0.491 mm/s at 4.2 K and 6n = 0.233 mm/s and fib = 0.357 mm/s at 275 K (relative to metallic iron), with an estimated error of 0.005 mm/s. Both 6A and fib are observed to decrease with increasing AI concentration. The effective hyperfine fields for the non-substituted maghemite sample are: Hefr.A = 575 kOe and Hofr.B = 471 kOe at 4.2 K and He~,A = 562 kOe and H~er.B = 449 kOe at 275 K, with an error of 1 kOe. The B-site hyperfine field remains approximately constant with A1 substitution, while for the A site a slight decrease with increasing A1 content was observed.