Characterization of the porosity developed in a new titania-alumina catalyst support prepared by the sol gel route

Titanium oxide (TiO2) is a good candidate for support of hydrotreating catalysts but has the disadvantage of presenting a low surface area and a poor thermal stability when compared with Al2O3. A mixed TiO2-Al2O3 support was proposed as an alternative that is expected to be free from these drawbacks. The variation during firing of the nanoporous texture of supports composed of TiO2-Al2O3, TiO2 and Al2O3 was studied by small angle X-ray scattering (SAXS). The supports were prepared by the sol-gel route using Ti and Al isopropoxides. We have particularly analyzed the effects of acid and basic hydrolysis on the nanostructural features of catalyst supports fired at different temperatures. The nanopore radius distribution functions were determined from SAXS results assuming a simple model of spherical nanopores embedded in a homogeneous solid matrix. The modal pore radius in both pure TiO2 and pure Al2O3 supports grows from 1.3 to 2.2 nm as the firing temperature increases from 673 to 973 K. on the other hand, the modal pore radius in the mixed TiO2-Al2O3 support remains below 1.2 nm over the same range of firing temperatures. These results demonstrate the good thermal stability of the nanoporous texture of mixed TiO2-Al2O3 supports.

Thermal behavior of the maleic anhydride modified poly(3-hydroxybutyrate)

Poly(3-hydroxybutyrate), PHB has been structurally modified through reaction with maleic anhydride, MA. Transesterification reaction was carried out fixing the PHB and MA and besides time and temperature the concentration of the triethylamine (used as catalyst) was changed. Glass transition, melting and crystallization temperature obtained from DSC curves and thermal degradation temperatures obtained from TG traces were used to evaluate the influence of the reaction conditions on the modification of PHB according to factorial design. on the base of the results the optimum conditions are to perform the PHB modification reaction with MA reaction at 110 degrees C for 1 h with 5% v/v triethylamine.

Selection and shell relationship in Isocheles-sawayai forest and Saint-laurent, 1967 (crustacea, anomura, diogenidae)

A populational sample of Isocheles sawayai Forest & Saint Laurent, 1967 was analysed in order to detect the validity of the shell aperture size as a parameter in the gastropod shell selection. The gastropods genus occupied by this hermit crab were: Thais, Buccinanops, Olivancillaria, Polinices and Cymatium. The power function (y = a.x(b)) was the best equation to represent biologically the regression analyses carried out among the measured parameters.

Influence of solid wastes in the mycelium growth of Lentinula edodes (berk.) Pegler

In Brazil there was little research related to Shiitake axenic culture. The aim of this research was to understand the substratum effects in the kinetics of the Shiitake mycelium growth. It was used two Shiitake strains and two different base substrate (eucalyptus sawdust and sugar cane bagasse) varying in three proportions of the supplements. The supplements, a blend of rice and wheat brans, were added in the proportion of 0, 10 and 20% of the base substrate. The experiment was composed of six treatments. The mycelium growth kinetics in volume had no effect relation to the strains and substrate and it followed a mathematical model represented by logarithmic equation. Beta, gamma and delta parameters didn't show any correlation with the growth velocity in volume. The strain L55 was better adapted than L17.

Nanostructure and properties of ZnO films produced by the pyrosol process

Indium doped ZnO films were deposited by the pyrosol process on glass substrates at different temperatures from solutions containing In/Zn molar ratios up to 10%. The nanostructure of the films was investigated using grazing-incidence small angle X-ray scattering (GISAXS). The mass density was determined by X-ray reflectivity and the composition by X-ray photoelectron spectroscopy. The GISAXS measurements revealed an anisotropic pattern for films deposited at 573 and 623 K and a isotropic one for those deposited at higher temperatures. The anisotropic patterns indicate the presence of elongated nanopores with their long axes perpendicular to the film surface. In contrast, the isotropic nature of GISAXS patterns of films grown at high temperatures (673 and 723 K) suggests the presence of spherical voids. The pore size distribution function determined from the isotropic patterns indicates a multimodal size distribution. on the other hand, the measured mass density of the doped films with isotropic nanotexture is higher than that of the anisotropic films while the electric resistivity is significantly lower. This is in agreement with the detected strong reduction of the void density and specific surface area at approximately constant pore size.

Thermotectonic and fault dynamic analysis of Precambrian basement and tectonic constraints with the Parana basin

The Precambrian crystalline basement of southeast Brazil is affected by many Phanerozoic reactivations of shear zones that developed during the end of the Neoproterozoic in the Brasiliano orogeny. These reactivations with specific tectonic events, a multidisciplinary study was done, involving geology, paleostress, and structural analysis of faults, associated with apatite fission track methods along the northeastern border of the Parana basin in southeast Brazil.The results show that the study area consists of three main tectonic domains, which record different episodes of uplift and reactivation of faults. These faults were brittle in character and resulted in multiple generations of fault products as pseudotachylytes and ultracataclasites, foliated cataclasites and fault gouges.Based on geological evidence and fission track data, an uplift of basement rocks and related tectonic subsidence with consequent deposition in the Parana basin were modeled.The reactivations of the basement record successive uplift events during the Phanerozoic dated via corrected fission track ages, at 387 +/- 50 Ma (Ordovician); 193 +/- 19 Ma (Triassic); 142 +/- 18 Ma (Jurassic), 126 +/- 11 Ma (Early Cretaceous); 89 +/- 10 Ma (Late Cretaceous) and 69 +/- 10 Ma (Late Cretaceous). These results indicate differential uplift of tectonic domains of basement units, probably related to Parana basin subsidence. Six major sedimentary units (supersequences) that have been deposited with their bounding unconformities, seem to have a close relationship with the orogenic events during the evolution of southwestern Gondwana. (c) 2005 Elsevier Ltd. All rights reserved.

Influence of processing conditions on the thermal decomposition of SrTiO3 precursors

The present work investigates the influence of milling and calcination atmosphere on the thermal decomposition of SrTiO3 powder precursors. Both pure and neodymium-modified SrTiO3 samples were studied. Milling did not significantly influence numerical mass loss value, but reduced the number of decomposition steps, modifying the profiles of the TG and DTA curves. on the other hand, milling increases the amount of energy liberated by the system upon combustion of organic matter. It was also observed that the milling process, associated to the calcination in an oxygen atmosphere, considerably decreases the amount of organic matter and increases the final mass loss temperature.

Crystal structure of a novel myotoxic Arg49 phospholipase A(2) homolog (zhaoermiatoxin) from Zhaoermia mangshanensis snake venom: Insights into Arg49 coordination and the role of Lys122 in the polarization of the C-terminus

The venom of Zhaoermia mangshanensis, encountered solely in Mt Mang in China's Hunan Province, exhibits coagulant, phosphodiesterase, L-amino acid oxidase, kallikrein, phospholipase A(2) and myotoxic activities. The catalytically inactive PLA(2) homolog referred to as zhaoermiatoxin is highly myotoxic and displays high myonecrotic and edema activities. Zhaoermiatoxin possesses a molecular weight of 13,972 Da, consists of 121 amino-acid residues crosslinked by seven disulfide bridges and shares high sequence homology with Lys49-PLA(2)s from the distantly related Asian pitvipers. However, zhaoermiatoxin possesses an arginine residue at position 49 instead of a lysine, thereby suggesting a secondary Lys49 -> Arg substitution which results in a catalytically inactive protein. We have determined the first crystal structure of zhaoermiatoxin, an Arg49-PLA(2), from Zhaoermia mangshanensis venom at 2.05 A resolution, which represents a novel member of phospholipase A(2) family. In this structure, unlike the Lys49 PLA(2)s, the C-terminus is well ordered and an unexpected non-polarized state of the putative calcium-binding loop due to the flip of Lys122 towards the bulk solvent is observed. The orientation of the Arg-49 side chain results in a similar binding mode to that observed in the Lys49 PLA(2)s; however, the guadinidium group is tri-coordinated by carbonyl oxygen atoms of the putative calcium-binding loop, whereas the N zeta atom of lysine is tetra-coordinated as a result of the different conformation adopted by the putative calcium-binding loop. (c) 2008 Elsevier Ltd. All rights reserved.

The antibacterial effects for Salmonella Enteritidis phage type 4 of different chemical disinfectants and cleaning agents tested under different conditions

A selection of commercially available disinfectants, sanitizers and water sanitizers based on iodophor, quaternary ammonium compounds (QACs) and phenolic compounds were tested for their activity against a phage type 4 strain of Salmonella serotype Enteritidis in the presence of a variety of organic materials. In general the phenolic preparations were the most effective followed by the QACs and the iodophors. They were all inactivated to different degrees by chick fluff, chicken faeces, feed and wood shavings. The inactivation was greatest when Salmonella organisms were pre-dried in feed. Under these conditions formaldehyde and glutaraldehyde were still active. There was some evidence that induced resistance to stress conditions including culture at 42°C and anaerobic culture increased resistance to one of the water sanitizers.

Solid mass falling into the reservoirs shallow water equations validity from the engineering point of view

Water waves generated by a solid mass is a complex phenomenon discussed in this paper by numerical and experimental approaches. A model based on shallow water equations with shocks (Saint Venant) has developed. It can reproduce the amplitude and the energy of the wave quite well, but because it consistently generates a hydraulic jump, it is able to reproduce the profile, in the case of high relative thickness of slide, but in the case of small relative thickness it is unable to reproduce the amplitude of the wave. As the momentum conservation is not verified during the phase of wave creation, a second technique based on discharge transfer coefficient α, is introduced at the zone of impact. Numerical tests have been performed and validated this technique from the experimental results of the wave's height obtained in a flume.

Two definitions of the electric polarizability of a bound system in relativistic quantum theory

For the electric polarizability of a bound system in relativistic quantum theory, there are two definitions that have appeared in the literature. They differ depending on whether or not the vacuum background is included in the system. A recent confusion in this connection is clarified. © 1999 American Associations of Physics Teachers.

Morphology of the walls of the cavernous sinus of Cebus apella (tufted capuchin monkey)

The morphology of the dura mater and its relationship with the structures of the cavernous sinus were analyzed in five tufted capuchin monkeys (Cebus apella) using histological sections, showing that the walls of the cavernous sinus of this species are similar to those of other primates, including man. Except for the medial wall of the cavernous sinus, the remaining walls consist of two distinct dura mater layers. The deep layer of the lateral wall of the cavernous sinus is contiguous to the sheath of the oculomotor, trochlear and ophthalmic nerves. Arterioles, venules, venous spaces, neuronal bodies and nervous fiber bundles are found on this lateral wall.

Non-Specific Interaction between Ants (Hymenoptera; Formicidae) and Fruits of Syagrus romanzoffiana (Arecaceae) in an Area of the Brazilian Atlantic Forest

On the forest floor of a fragment of the Atlantic Forest which is considered to be in a stage of recuperation, located in southeastern Brazil, we recorded 54 species of ants interacting with the fruits of Syagrus romanzoffiana (Arecaceae). Myrmicinae was the subfamily which was the richest in species, followed by Ponerinae, Formicinae, Ecitoninae, Dolichoderinae, Pseudomyrmecinae and Cerapachyinae. The fruits of S. romanzoffiana can be classified according to whether or not they are preyed by the squirrel Sciurus ingrami, and the ant fauna that visits the fruits has an average similarity. Regarding diversity, the data suggest that there is no significant difference between ant assemblages at preyed and non-preyed-upon fruit falls. The results also indicate that there is no specific interaction between the ant fauna that visits the fruits of S. romanzoffiana, as it consists largely of species with omnivorous feeding habits.

Kinetic study of the plastoquinone pool availability correlated with H2O2 release in seawater and antioxidant responses in the red alga Kappaphycus alvarezii exposed to single or combined high light, chilling and chemical stresses

Under biotic/abiotic stresses, the red alga Kappaphycus alvarezii reportedly releases massive amounts of H2O2 into the surrounding seawater. As an essential redox signal, the role of chloroplast-originated H2O2 in the orchestration of overall antioxidant responses in algal species has thus been questioned. This work purported to study the kinetic decay profiles of the redox-sensitive plastoquinone pool correlated to H2O2 release in seawater, parameters of oxidative lesions and antioxidant enzyme activities in the red alga Kappaphycus alvarezii under the single or combined effects of high light, low temperature, and sub-lethal doses of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), which are inhibitors of the thylakoid electron transport system. Within 24 h, high light and chilling stresses distinctly affected the availability of the PQ pool for photosynthesis, following Gaussian and exponential kinetic profiles, respectively, whereas combined stimuli were mostly reflected in exponential decays. No significant correlation was found in a comparison of the PQ pool levels after 24 h with either catalase (CAT) or ascorbate peroxidase (APX) activities, although the H2O2 concentration in seawater (R = 0.673), total superoxide dismutase activity (R = 0.689), and particularly indexes of protein (R = 0.869) and lipid oxidation (R = 0.864), were moderately correlated. These data suggest that the release of H2O2 from plastids into seawater possibly impaired efficient and immediate responses of pivotal H2O2-scavenging activities of CAT and APX in the red alga K. alvarezii, culminating in short-term exacerbated levels of protein and lipid oxidation. These facts provided a molecular basis for the recognized limited resistance of the red alga K. alvarezii under unfavorable conditions, especially under chilling stress. © 2006 Elsevier B.V. All rights reserved.

Serum biochemical parameters in the ring-necked pheasant (Phasianus colchicus) on breeding season

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)