pK determination. A mean field, Poisson-Boltzmann approach

A model describing dissociation of monoprotonic acid and a method for the determination of its pK value are presented. The model is based on a mean field approximation. The Poisson-Boltzmann equation, adopting spherical symmetry, is numerically solved, and the solution of its linearized form is written. By use of the pH values of a dilution experiment of galacturonic acid as the entry data, the proposed method allowed estimation of the value of pK = 3.25 at a temperature of 25 degrees C. Values for the complex dimensions and dissociation degree are calculated using experimental pH values for solution concentration values ranging from 0.1 to 60 mM. The present analysis leads to the conclusion that the Poisson-Boltzmann equation or its linear form is equally suited for the description of such systems.

Study of pK Values and Effective Dielectric Constants of Ionizable Residues in Pentapeptides and in Staphylococcal Nuclease (SNase) Using a Mean-Field Approach

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

Cimetidine-induced Leydig cell apoptosis and reduced EG-VEGF (PK-1) immunoexpression in rats: evidence for the testicular vasculature atrophy

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

Signatures of doubly charged Higgs in the SU(3)(L) circle times U(1)(N) model at the CERN LHC

The scalar sector of the simplest version of the 3-3-1 electroweak model is constructed with three Higgs triplets only. We show that a relation involving two of the constants of the model, two vacuum expectation values of the neutral scalars, and the mass of the doubly charged Higgs boson leads to important information concerning the signals of this scalar particle.

Calculable lepton masses, seesaw relations, and four neutrino mixings in a 3-3-1 model with an extra U(1) symmetry

We propose a scheme in which the masses of the heavier leptons obey seesaw type relations. The light lepton masses, except the electron and the electron neutrino ones, are generated by one loop level radiative corrections. We work in a version of the 3-3-1 electroweak model that predicts singlets (charged and neutral) of heavy leptons beyond the known ones. An extra U(1)(Omega) symmetry is introduced in order to avoid the light leptons getting masses at the tree level. The electron mass induces an explicit symmetry breaking at U(1)(Omega). We discuss also the mixing matrix among four neutrinos. The new energy scale required is not higher than a few TeV.

Neutral Higgs bosons in the SU(3)(L)circle times U(1)(N) model

The SU(3)(L)circle times U(1)(N) electroweak model predicts new Higgs bosons beyond the one of the standard model. In this work we investigate the signature and production of neutral SU(3)(L)circle times U(1)(N) Higgs bosons in the e(-)e(+) Next Linear Collider and in the CERN Linear Collider . We compute the branching ratios of two of the SU(3)(L)circle times U(1)(N) neutral Higgs bosons and study the possibility to detect them and the Z' extra neutral boson of the model.

Doubly charged Higgs through photon-photon collisions in 3-3-1 models

We study the production and signatures of doubly charged Higgs bosons (DCHBs) in the process gamma gamma <-> H(--)H(++) at the e(-)e(+) International Linear Collider and CERN Linear Collider, where the intermediate photons are given by the Weizsacker-Willians and laser backscattering distributions.

Probing doubly charged Higgs bosons in e(+)e(-) colliders at the ILC and the CLIC in a 3-3-1 model

The SU(3)(L) circle times U(1)(N) electroweak model predicts new Higgs bosons beyond the one of the standard model. In this work we investigate the signature and production of doubly charged Higgs bosons in the e(+)e(-) International Linear Collider and in the CERN Linear Collider. We compute the branching ratios for the doubly charged gauge bosons of the model.

Structural Aspects of the Distinct Biochemical Properties of Glutaredoxin 1 and Glutaredoxin 2 from Saccharomyces cerevisiae

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

Avaliação das indicações de ceratoplastia penetrante no interior paulista

Objective: To determinate the corneal diagnoses of patients underwent Penetrating Keratoplasty (PK) in the university hospital of Sao Jose do Rio Preto, São Paulo, Brazil, and their relation to age group, gender and socioeconomic factors. Methods: Retrospective analysis of 1085 registration forms of patients underwent Penetrating Keratoplasty in the university hospital of Sao Jose do Rio Preto, São Paulo, Brazil, from 2000 to 2009. The surgical indications were then correlated to age group, gender and socioeconomic factors, by chi-square test. Results: Fifty-seven percent of all Penetrating Keratoplasties were performed in male patients, and the mean age was 52.3 years. Most surgeries (90.8%) occurred by means of public health care (SUS). The main diagnosis was leukoma (23%), representing 14% of the indications for PK in males and 9% in females. Leukoma was also the diagnosis in 40% of PK performed in patients older than 60 years and in 94.4% of these surgeries in public health care users. Conclusion: The main indication for Penetrating Keratoplasty was leukoma, predominating in males, ages above 60 years and in public health care users.

Efeito da adubação na manifestação da resistência de feijoeiro ao ataque de caruncho em testes com e sem chance de escolha

Objetivando-se estudar a influência da adubação na manifestação da resistência de feijoeiro (Phaseolus vulgaris L.) (cultivares Rosinha G-2, ESAL-564 - Carioca e Diamante Negro) ao ataque de Acanthoscelides obtectus (Say, 1831) (Coleoptera: Bruchidae) foram conduzidos, na época das águas, testes com e sem chance de escolha, utilizando-se grãos obtidos de parcelas adubadas com N, P, K, NP, NK, PK, NPK, e sem adubo, totalizando 24 tratamentos. Os testes foram realizados em condições controladas de temperatura, umidade e luz. Foram avaliados o número de insetos atraídos e de ovos, em cada tratamento. Concluiu-se, no teste com chance de escolha, que o número de ovos de A. obtectus por recipiente foi reduzido pela aplicação do nitrogênio. A aplicação de nitrogênio em adubação resultou em menor porcentagem de insetos atraídos e menor número de ovos no genótipo Rosinha G-2. A manifestação da resistência nos genótipos ESAL-564 e Rosinha G-2 ao ataque de A. obtectus ficou evidente quando utilizados nitrogênio e potássio. Nos testes sem chance de escolha o consumo dos insetos foi reduzido nos grãos produzidos com a aplicação do nitrogênio. A aplicação de nitrogênio em adubação resultou no aumento do número de ovos de A. obtectus no genótipo ESAL-564. Não ficou evidente a manifestação da resistência nos genótipos ESAL-564 e Rosinha G-2 ao ataque do caruncho, pela aplicação dos macronutrientes N, P e K. Na ausência de fósforo o ciclo biológico do inseto foi maior na presença de potássio.

Study of caffeine urine and saliva of horses subjected to urinary acidification

The study of caffeine in racing horses has been of growing concern in veterinary sports medicine since the Association of Racing Commissioners International (ARCI) stated that it has no valid therapeutic use in racehorses. We examined the kinetic alterations in the urinary excretion and salivary secretion of caffeine in seven horses subjected to urinary acidification using ascorbic acid because this procedure can simulate the acidosis that follows anaerobic exercise. They participated in two treatment groups: the control group (SG) received 500 ml of saline and then 2.0 mg kg(-1) caffeine i.v. 30 min later; and the acidified group (AG) was subjected to urinary acidification with ascorbic acid at a dose of 0.5 g kg(-1) i.v. and then 2.0. mg kg(-1) caffeine i.v. 30 min later. Samples were collected 30 min before caffeine administration, immediately before caffeine administration (time zero) and at 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 48 and 72 h afterwards. The samples were assayed by gas chromatography. The mean urinary pH for SG was 8.2, but for AG it was as low as 5.9 at 4 h, extending acidosis for up to 8 h. The kinetic curves for the two groups were similar for urinary excretion and salivary secretion. Differences occurred only in peak excretion and peak secretion in SG obtained at 1 h and 30 min, respectively, and in AG at 2 h and 1 h, respectively. This could be explained, in part, to the diuresis in AG compared with SG, resulting in less concentrated urine in the former group. The large difference between the pK(a) of caffeine and the pH of the medium may be responsible for the similar pharmacokinetics observed for the two groups. Copyright (C) 2004 John Wiley Sons, Ltd.

Protein Hydrolysis by Immobilized and Stabilized Trypsin

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Vortices in a mesoscopic superconducting circular sector

In the present paper we develop an algorithm to solve the time dependent Ginzburg-Landau equations, by using the link variables technique, for circular geometries. In addition, we evaluate the Helmholtz and Gibbs free energy, the magnetization, and the number of vortices. This algorithm is applied to a circular sector. We evaluate the superconduting-normal magnetic field transition, the magnetization, and the superconducting density. Our results point out that, as we reduce the superconducting area, the nucleation field increases. Nevertheless, as the angular width of the circular sector goes to small values the asymptotic behavior is independent of the sample area. We also show that the value of the first nucleation field is approximately the same independently of the form of the circular sector. Furthermore, we study the nucleation of giant and multivortex states for the different shapes of the present geometry.

Excitations and finite-size properties of an integrable supersymmetric electronic model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)