Morphological and Chemical Investigation of Ovarian Structures in a Bovine Model by Contrast-Enhanced X-ray Imaging and Microscopy

An improved understanding of an ovary’s structures is highly desirable to support advances in folliculogenesis knowledge and reproductive medicine, with particular attention to fertility preservation options for prepubertal girls with malignant tumors. Although currently the golden standard for structural analysis is provided by combining histological sections, staining, and visible 2D microscopic inspection, synchrotron radiation phase-contrast microtomography is becoming a new challenge for three-dimensional studies at micrometric resolution. To this aim, the proper use of contrast agents can improve the visualization of internal structures in ovary tissues, which normally present a low radiopacity. In this study, we report a comparison of four staining protocols, based on iodine or tungsten containing agents, applied to bovine ovarian tissues fixed in Bouin’s solution. The microtomography (microCT) analyses at two synchrotron facilities under different set-ups were performed at different energies in order to maximize the image contrast. While tungsten-based agents allow large structures to be well identified, Iodine ones better highlight smaller features, especially when acquired above the K-edge energy of the specific metal. Further scans performed at lower energy where the setup was optimized for overall quality and sensitivity from phase-contrast still provided highly resolved visualization of follicular and intrafollicular structures at different maturation stages, independent of the staining protocol. The analyses were complemented by X-ray Fluorescence mapping on 2D sections, showing that the tungsten-based agent has a higher penetration in this type of tissues

Polymer/layered silicate nanocomposite as matrix for bioinsecticide formulation.

Due to current encouragement to the use of bioinsecticides for pest control and the susceptibility of biological agents to external factors, we investigated the use of a polymer nanocomposite (PLN, polymer/ layered silicate nanocomposite) as matrix to encapsulate an entomopathogenic fungus active against pest insects of palm trees. The beads were formed by extrusion and the following variables were assessed: fungus conidial concentration (series 1: 107; series 2: 108 and series 3:109 conidia/mL) and nanolayered silicate concentration (0; 0.5; 1; 2 and 4%). The matrix was evaluated by X-ray powder diffraction and Fourier transform infrared spectroscopy and the following characteristics of the products were assessed: percent of encapsulated conidia, size distribution and polydispersity index, swelling index, formulation?s in vitro ability to release conidia and stability under different storage temperatures. PLN, whose interactions could be visualized by FTIR, proved to be a potential matrix for this fungus, because, while composed by natural substances non-toxic to the environment, it succeeded to encapsulate high amounts of conidia (series 2). A barrier effect with bentonite increase was also demonstrated by increased fungus germination time and thermal stability

Determinação de minerais em grãos de milho: avaliação de contaminações durante o preparo de amostras.

O melhoramento de culturas com altos teores de minerais, principalmente Fe e Zn, é uma nova iniciativa no combate à desnutrição, como proposto pelo Programa Harvest Plus. A obtenção de dados analíticos confiáveis sobre carotenóides, pró-vitamínicos A e microminerais nos alimentos escolhidos pelo programa, in natura, processados ou preparados para o consumo, do campo à mesa, é imprescindível para cumprir seus objetivos. Assim, para aumento de confiabilidade, esse programa necessita gerar conhecimento básico sobre as análises de tais características, desenvolvendo protocolos de amostragem e análise para as diversas culturas envolvidas, procurando-se evitar erros relacionados à amostragem ou possíveis contaminações durante as fases de coleta e preparo das amostras. Os protocolos devem atender características relacionadas a custos, exatidão e precisão, além de promover respostas rápidas para facilitar a identificação de genótipos promissores e para treinamento do corpo técnico envolvido aumentando o poder das pesquisas em elementos-traço nas diversas culturas (Stangoulis, 2005). Os analistas devem ser muitos bem informados sobre a natureza e propriedades dos elementos determinados, assim como das fontes de erros na sua identificação e quantificação (Amaya, 2005).SCHAFFERT, R. E

Higher Order Evaluation of the Critical Temperature for Interacting Homogeneous Dilute Bose Gases

We use the nonperturbative linear \delta expansion method to evaluate analytically the coefficients c_1 and c_2^{\prime \prime} which appear in the expansion for the transition temperature for a dilute, homogeneous, three dimensional Bose gas given by T_c= T_0 \{1 + c_1 a n^{1/3} + [ c_2^{\prime} \ln(a n^{1/3}) +c_2^{\prime \prime} ] a^2 n^{2/3} + {\cal O} (a^3 n)\}, where T_0 is the result for an ideal gas, a is the s-wave scattering length and n is the number density. In a previous work the same method has been used to evaluate c_1 to order-\delta^2 with the result c_1= 3.06. Here, we push the calculation to the next two orders obtaining c_1=2.45 at order-\delta^3 and c_1=1.48 at order-\delta^4. Analysing the topology of the graphs involved we discuss how our results relate to other nonperturbative analytical methods such as the self-consistent resummation and the 1/N approximations. At the same orders we obtain c_2^{\prime\prime}=101.4, c_2^{\prime \prime}=98.2 and c_2^{\prime \prime}=82.9. Our analytical results seem to support the recent Monte Carlo estimates c_1=1.32 \pm 0.02 and c_2^{\prime \prime}= 75.7 \pm 0.4.Comment: 29 pages, 3 eps figures. Minor changes, one reference added. Version in press Physical Review A (2002

Ferramentas participativas no manejo da agrobiodiversidade da Comunidade Vereda do Mari (Sento Sé-BA).

O presente trabalho teve como objetivo investigar se cinco ferramentas participativas são suficientes para diagnosticar a agrobiodiversidade na comunidade Vereda do Mari (Sento Sé-BA), em Julho de 2011. Foram aplicadas as ferramentas Linha do Tempo, Diagrama de Venn e Fluxos, Mapa Histórico da Agrobiodiversidade, Lista da Agrobiodiversidade e o Calendário de Cultivos Focando o Gênero. A aplicação das ferramentas forneceu informações gerais sobre a agrobiodiversidade que podem ser detalhadas com a realização do Registro Comunitário da Agrobiodiversidade, que detalha cada variedade local