Effect of alveolex on the bone defects repair stimulated by rhBMP-2: Histomorphometric study

OBJECTIVE: The aim of this study was to evaluate histomorphometrically the effect of alveolex (Propolis 10%) on the repair of bone cavities in the calvaria of rats. MATERIALS and METHODS: A 5 mm diameter bone defect was made in the calvaria of male Wistar rats using the drill-type trephine. The defects were filled with rhBMP-21Alveolex, rhBMP-2, Alveolex, or coagulum. Twenty-eight animals with seven subjects on each were sacrificed 30 days after surgery and samples were fixed and embedded in paraffin. Histological sections stained by HE (hematoxylin and eosin) were obtained from the calvaria bone defect and analyzed by a differential point-counting method. RESULTS: Group I and II, rhBMP-21Alveolex and rhBMP-2, respectively, presented higher levels of newly formed bone than other groups (P < 0.001). There were not significant differences between groups I and II (P > 0.05). In addition, there was not significant difference between groups III and IV, Control-Coagulum and Alveolex, respectively (P > 0.05). CONCLUSION: Alveolex has increased the bone repair in calvaria defects of rats when associated to rhBMP-2, however without significant differences for rhBMP-2 isolated group; Alveolex isolated group showed the lowest levels of newly formed bone with no significant differences to coagulum group (control). Microsc. Res. Tech. 75: 36-41, 2012. (C) 2011 Wiley Periodicals, Inc.

The light-cone gauge without prescriptions

Feynman integrals in the physical light-cone gauge are more difficult to solve than their covariant counterparts. The difficulty is associated with the presence of unphysical singularities due to the inherent residual gauge freedom in the intermediate boson propagators constrained within this gauge choice. In order to circumvent these non-physical singularities, the headlong approach has always been to call for mathematical devices - prescriptions - some successful and others not. A more elegant approach is to consider the propagator from its physical point of view, that is, an object obeying basic principles such as causality. Once this fact is realized and carefully taken into account, the crutch of prescriptions can be avoided altogether. An alternative, third approach, which for practical computations could dispense with prescriptions as well as avoiding the necessity of careful stepwise consideration of causality, would be of great advantage. and this third option is realizable within the context of negative dimensions, or as it has been coined, the negative dimensional integration method (NDIM).

Light-cone gauge integrals: prescriptionlessness at two loops

The only calculations performed beyond one-loop level in the light-cone gauge make use of the Mandelstam-Leibbrandt (ML) prescription in order to circumvent the notorious gauge dependent poles. Recently we have shown that in the context of negative dimensional integration method (NDIM) such prescription can be altogether abandoned, at least in one-loop order calculations. We extend our approach, now studying two-loop integrals pertaining to two-point functions. While previous works on the subject present only divergent parts for the integrals, we show that our prescriptionless method gives the same results for them, besides finite parts for arbitrary exponents of propagators. (C) 2000 Elsevier B.V. B.V. All rights reserved.

NDIM achievements: massive, arbitrary tensor rank and N-loop insertions in Feynman integrals

One of the main difficulties in studying quantum field theory, in the perturbative regime, is the calculation of D-dimensional Feynman integrals. In general, one introduces the so-called Feynman parameters and, associated with them, the cumbersome parametric integrals. Solving these integrals beyond the one-loop level can be a difficult task. The negative-dimensional integration method (NDIM) is a technique whereby such a problem is dramatically reduced. We present the calculation of two-loop integrals in three different cases: scalar ones with three different masses, massless with arbitrary tensor rank, with and N insertions of a two-loop diagram.

Two-Point Function at Two Loops via Triangle Diagram Insertion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dimensão fractal na quantificação do grau de rejeição celular miocárdica pós-transplante cardíaco

INTRODUÇÃO: O termo fractal é derivado do latim fractus, que significa irregular ou quebrado, considerando a estrutura observada como tendo uma dimensão não-inteira. Há muitos estudos que empregaram a Dimensão Fractal (DF) como uma ferramenta de diagnóstico. Um dos métodos mais comuns para o seu estudo é a Box-plot counting (Método de contagem de caixas). OBJETIVO: O objetivo do estudo foi tentar estabelecer a contribuição da DF na quantificação da rejeição celular miocárdica após o transplante cardíaco. MÉTODOS: Imagens microscópicas digitalizadas foram capturadas na resolução 800x600 (aumento de 100x). A DF foi calculada com auxílio do software ImageJ, com adaptações. A classificação dos graus de rejeição foi de acordo com a Sociedade Internacional de Transplante Cardíaco e Pulmonar (ISHLT 2004). O relatório final do grau de rejeição foi confirmado e redefinido após exaustiva revisão das lâminas por um patologista experiente externo. No total, 658 lâminas foram avaliadas, com a seguinte distribuição entre os graus de rejeição (R): 335 (0R), 214 (1R), 70 (2R), 39 (3R). Os dados foram analisados estatisticamente com os testes Kruskal-Wallis e curvas ROC sendo considerados significantes valores de P < 0,05. RESULTADOS: Houve diferença estatística significativa entre os diferentes graus de rejeição com exceção da 3R versus 2R. A mesma tendência foi observada na aplicação da curva ROC. CONCLUSÃO: ADF pode contribuir para a avaliação da rejeição celular do miocárdio. Os valores mais elevados estiveram diretamente associados com graus progressivamente maiores de rejeição. Isso pode ajudar na tomada de decisão em casos duvidosos e naqueles que possam necessitar de intensificação da medicação imunossupressora.

Two-loop self-energy diagrams worked out with NDIM

In this work we calculate two two-loop massless Feynman integrals pertaining to self-energy diagrams using NDIM (Negative Dimensional Integration Method). We show that the answer we get is 36-fold degenerate. We then consider special cases of exponents for propagators and the outcoming results compared with known ones obtained via traditional methods.

Loop Integrals in Three Outstanding Gauges: Feynman, Light-Cone, and Coulomb

We apply the negative dimensional integration method (NDIM) to three outstanding gauges: Feynman, light-cone, and Coulomb gauges. Our aim is to show that NDIM is a very suitable technique to deal with loop integrals, regardless of which gauge choice that originated them. In the Feynman gauge we perform scalar two-loop four-point massless integrals; in the light-cone gauge we calculate scalar two-loop integrals contributing to two-point functions without any kind of prescriptions, since NDIM can abandon such devices - this calculation is the first test of our prescriptionless method beyond one-loop order; and finally, for the Coulomb gauge we consider a four-propagator massless loop integral, in the split-dimensional regularization context. © 2001 Academic Press.

First results for the Coulomb gauge integrals using NDIM

The Coulomb gauge has at least two advantages over other gauge choices in that bound states between quarks and studies of confinement are easier to understand in this gauge. However, perturbative calculations, namely Feynman loop integrations, are not well defined (there are the so-called energy integrals) even within the context of dimensional regularization. Leibbrandt and Williams proposed a possible cure to such a problem by splitting the space-time dimension into D = ω + ρ, i.e., introducing a specific parameter ρ to regulate the energy integrals. The aim of our work is to apply the negative dimensional integration method (NDIM) to the Coulomb gauge integrals using the recipe of split-dimension parameters and present complete results - finite and divergent parts - to the one- and two-loop level for arbitrary exponents of the propagators and dimension.

Distributed generation modelling for unbalanced three-phase power flow calculations in smart grids

Distributed Generators (DG) are generally modeled as PQ or PV buses in power flow studies. But in order to integrate DG units into the distribution systems and control the reactive power injection it is necessary to know the operation mode and the type of connection to the system. This paper presents a single-phase and a three-phase mathematical model to integrate DG in power flow calculations in distribution systems, especially suited for Smart Grid calculations. If the DG is in PV mode, each step of the power flow algorithm calculates the reactive power injection from the DG to the system to keep the voltage in the bus in a predefined level, if the DG is in PQ mode, the power injection is considered as a negative load. The method is tested on two well known test system, presenting single-phase results on 85 bus system, and three-phase results in the IEEE 34 bus test system. © 2011 IEEE.

Characterization of texture in image of skin lesions by support vector machine

Due to the increased incidence of skin cancer, computational methods based on intelligent approaches have been developed to aid dermatologists in the diagnosis of skin lesions. This paper proposes a method to classify texture in images, since it is an important feature for the successfully identification of skin lesions. For this is defined a feature vector, with the fractal dimension of images through the box-counting method (BCM), which is used with a SVM to classify the texture of the lesions in to non-irregular or irregular. With the proposed solution, we could obtain an accuracy of 72.84%. © 2012 AISTI.

Caracteres estruturais e dimensão fractal da folha de espécies de Arachis e sua relação com a cercosporiose

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Significado da presença de esquizócitos no sangue periférico de gestantes com pré-eclâmpsia

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

O fator (des)integrador da Amazônia e as relações Brasil- Peru de 2003 a 2008

Pós-graduação em Ciências Sociais - FCLAR

Efeito da estimulação do músculo tibial cranial após neurorrafia término-lateral do nervo fibular em ratos

Pós-graduação em Bases Gerais da Cirurgia - FMB