Soil-lime reactions: the behaviour of a Brazilian red soil.

A red tropical soil was selected, with the main purpose of investigating how it reacted with calcitic and dolomitic limes, and which products are formed. Under normal (23-28oC) or slightly accelerated (40o and 60oC) conditions there is a rapid and substantial interaction between lime (calcitic or dolomitic) and the soil. The reactions take place in two steps, one before 7 g lime/100 g soil, and the other after 8 g lime/100 g of soil, either for calcitic or dolomitic lime. A morphologically discrete reaction product (tri-calcium aluminate hexahydrate) was found in the study, and in spite of the difference in morphology the product is shown to be the same by XRD for all compositions and T.-J.M.H.

Pulpal and periodontal reactions of immature permanent teeth in the dog to intrusive trauma.

Pulpal and periodontal tissues of immature incisors of 10 dogs were radiographically and histopathologically evaluated immediately, 7, 15, 30 and 60 days after experimental intrusion induced by mechanical blows. Forty upper central and mesial lateral incisors showing incomplete root formation on radiographs were submitted to intrusive force. After the observation periods, the dogs were killed, two at a time. The hemi-maxilas were removed and processed for histopathologic examination. The traumatized teeth showed accelerated apical formation with reduced radicular length. Pulpal vitality was maintained and the subjacent tissues did not present irreversible changes. All traumatized teeth re-erupted spontaneously.

Description of inclusive meson spectra in e+e- annihilation reactions by a quark cascade model

We present a model to describe inclusive meson production in e+e- reactions based on a quark cascade approach whose formulation is put in terms of diffusion equations for three quark flavors (u, d, s). These equations are solved by using a formalism previously developed for the problem of the electromagnetic cascade generated in the atmosphere by cosmicray interactions. The obtained solutions are given in terms of a combination of power-law functions whose profiles are adequate to describe the characteristics observed in the inclusive spectrum of mesons.

Cross-reactions between Toxocara canis and Ascaris suum in the diagnosis of visceral larva migrans by western blotting technique

Visceral larva migrans (VLM) is a clinical syndrome caused by infection of man by Toxocara spp, the common roundworm of dogs and cats. Tissue migration of larval stages causes illness specially in children. Because larvae are difficult to detect in tissues, diagnosis is mostly based on serology. After the introduction of the enzyme-linked immunosorbent assay (ELISA) using the larval excretory-secretory antigen of T. canis (TES), the diagnosis specificity was greatly improved although cross-reactivity with other helminths are still being reported. In Brazil, diagnosis is routinely made after absorption of serum samples with Ascaris suum antigens, a nematode antigenicaly related with Ascaris lumbricoides which is a common intestinal nematode of children. In order to identify T. canis antigens that cross react to A. suum antigens we analyzed TES antigen by SDS-PAGE and Western blotting techniques. When we used serum samples from patients suspected of VLM and positive result by ELISA as well as a reference serum sample numerous bands were seen (molecular weight of 210-200 kDa, 116-97 kDa, 55-50 kDa and 35-29 kDa). Among these there is at least one band with molecular weight around 55-66 kDa that seem to be responsible for the cross-reactivity between T. canis and A. suum once it disappears when previous absorption of serum samples with A. suum antigens is performed.

Smooth landscape solvent dynamics in electron transfer reactions

Solvent effects play a major role in controlling electron-transfer reactions. The solvent dynamics happens on a very high-dimensional surface, and this complex landscape is populated by a large number of minima. A critical problem is to understand the conditions under which the solvent dynamics can be represented by a single collective reaction coordinate. When this unidimensional representation is valid, one recovers the successful Marcus theory. In this study the approach used in a previous work [V. B. P. Leite and J. N. Onuchic; J. Phys. Chem. 100, 7680 (1996)] is extended to treat a more realistic solvent model, which includes energy correlation. The dynamics takes place in a smooth and well behaved landscape. The single shell of solvent molecules around a cavity is described by a two-dimensional system with periodic boundary conditions with nearest neighbor interaction. It is shown how the polarization-dependent effects can be inferred. The existence of phase transitions depends on a factor y proportional to the contribution from the two parameters of the model. For the present model, γ suggests the existence of weak kinetic phase transitions, which are used in the analysis of solvent effects in charge-transfer reactions. © 1999 American Institute of Physics.

Coordinate-space Faddeev-Hahn-type approach to three-body charge-transfer reactions involving exotic particles

Low-energy muon-transfer cross sections and rates in collisions of muonic atoms with hydrogen isotopes are calculated using a six-state close-coupling approximation to coordinate-space Faddeev-Hahn-type equations. In the muonic case satisfactory results are obtained for all hydrogen isotopes and the experimentaly observed strong isotopic dependence of transfer rates is also reproduced. A comparison with results of other theoretical and available experimental works is presented. The present model also leads to good transfer cross sections in the well-understood problem of antihydrogen formation in antiproton-positronium collision.

Progress on holographic techniques to study photo-chemical reactions in solid state

In this paper it is presented recent developments in the heterodyne detection holographic techniques for studding photosensitive materials. The actual state of the technique allows simultaneous and independent measurement of the refractive index and of the absorption coefficient changes in photosensitive materials and their use to self-stabilize the fringe pattern. The modeling of the measured signal together with the fringe stabilization allow the long term-fitting of the optical properties and the study the photosensitive materials close to the saturation.

Comparative analysis of tissue reactions to anesthetic solutions: histological analysis in subcutaneous tissue of rats.

Postanesthetic pain is a relatively common complication after local anesthesia. This complication may be caused by the anesthetic technique or by the anesthetic solution used. Tissue reactions induced by the anesthetic solutions may be one of the factors resulting in pain after anesthesia. The objective of this study was to comparatively analyze tissue reactions induced by different anesthetic solutions in the subcutaneous tissue of rats. The following solutions were utilized: 2% lidocaine without vasoconstrictor; a 0.5% bupivacaine solution with 1:200,000 adrenaline; a 4% articaine solution and 2% mepivacaine, both with 1:100,000 adrenaline; and a 0.9% sodium chloride solution as a control. Sterilized absorbent paper cones packed inside polyethylene tubes were soaked in the solutions and implanted in the subcutaneous region. The sacrifice periods were 1, 2, 5, and 10 days after surgery. The specimens were prepared and stained with hematoxylin and eosin for histological analysis. The results showed that there is a difference in tissue irritability produced by the local anesthetic solutions. The results also showed that there is no relation between the concentration of the drug and the inflammatory intensity, that the mepivacaine and articaine solutions promoted less inflammatory reaction than the bupivacaine, and that the lidocaine solution produced the least intense inflammation.

Suicide nucleophilic attack: Reactions of benzohydroxamate anion with bis(2,4-dinitrophenyl) phosphate

(Chemical Equation Presented) The reaction between the benzohydroxamate anion (BHO-) and bis(2,4-dinitrophenyl)phosphate (BDNPP) has been examined kinetically, and the products were characterized by mass and NMR spectroscopy. The nucleophilic attack of BHO- follows two reaction paths: (i) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement to phenyl isocyanate, aniline, diphenylurea, and O-phenylcarbamyl benzohydroxamate; and (ii) on the aromatic carbon, giving an intermediate that was detected but slowly decomposes to aniline and 2,4-dinitrophenol. Thus, the benzohydroxamate anion can be considered a self-destructive molecular scissor since it reacts and loses its nucleophilic ability. © 2009 American Chemical Society.

The reactions of the governments of Latin America and the Caribbean to the international crisis: an overview of policy measures up to 31 May 2009

Includes bibliography

The reactions of the governments of the Americas to the international crisis: an overview of policy measures up to 31 December 2009

Includes bibliography

The reactions of the Governments of the Americas to the international crisis: follow-up to policy measures adopted up to 31 December 2011. (Preliminary version)

Includes Bibliography

The University and its libraries: Reactions and resistance to scientific publishers

This paper addresses the relationship of copyright and the right of universities on scientific production. Information and Communication Technologies (ICTs) are causing many changes in the system of scientific communication, such as the creation of Institutional Repositories that aim to gather scientific production in digital format. The University needs quicker ways of spreading academic production and many questions are emerging due to contexts such as the Open Access movement. Thus, this paper questions the positioning of Universities, especially Public Universities, which despite having policies related to intellectual property to protect the transferring forms of research results to society; many times do not have a positioning or a mechanism that regulates the self-deposit of scientific production in these Institutional Repositories. In order to develop this paper, the following issues are addressed: lack of interest of the University in storing scientific production; reports on the relationship of the library with scientific publishing houses; the participation of faculty members and students in supporting the Free Access movement; and initiatives aimed at greater flexibility of copyright to the context of scientific production. In order to follow the development of these issues at international level, it was opted for qualitative research with non-participating direct observation to carry out the identification and description of copyright policy of important publishers from the ROMEO SHERPA site; therefore, it can be observed that there are changes regarding the publishers' flexibility before self-archiving of authors in open access institutional repositories in their universities. Given this scenario, we presente reflections and considerations that involve the progress and mainly the integration of the University and its faculty members; the institution should recommend and guide its faculty members not to transfer their copyrights, but to defend their right of copy to Institutional Repositories along with Publishing Houses.

Functional nanostructured catalysts based on the niobates to the dry methane reforming and ethylene homologation reactions

Catalytic activity and selectivity of niobate-based nanostructured materials were investigated. Dry methane reforming (DMR) and ethylene homologation reaction (EHR) were selected as test reactions. KSr 2Nb5O15, Sr2NaNb5O 15 and NaSr2(NiNb4)O15 δ niobate powders were prepared by the high energy ball milling method and calcined in a reductor atmosphere. N2 adsorption isotherms, X-ray diffraction and infrared spectroscopy characterization was performed. Hydrogen pretreated niobates showed from low to moderate catalytic initial activity in DMR's test, nevertheless the materials were deactivated rapidly and the kinetic parameters associated to deactivation were estimated. Otherwise, non-treated catalysts showed a high initial activity in EHR's test and KSr2Nb 5O15 catalyst requires 24 h to the total deactivation with a high selectivity to form propylene. A reaction mechanism to the propylene formation is discussed. © 2012 Elsevier Ltd. All rights reserved.