Axial mixing in rotating drums using magnetic resonance imaging using bran as a model for solid state fermentations

Magnetic resonance imaging (MRI) is an easily automated, reliable technique to investigate axial mixing within rotating drums. Moist bran can be clearly differentiated from dry bran using MRI allowing a non-segregating tracer for axial mixing. For a 20-cm diameter drum, the axial dispersion coefficient in the particle bed was 0.51 cm s(-2). Axial dispersion is scale-dependent.

An Analytic Simplification for the Reconstruction Problem of Electrical Impedance Tomography

This paper introduces a new reconstruction algorithm for electrical impedance tomography. The algorithm assumes that there are two separate regions of conductivity. These regions are represented as eccentric circles. This new algorithm then solves for the location of the eccentric circles. Due to the simple geometry of the forward problem, an analytic technique using conformal mapping and separation of variables has been employed. (C) 2002 John Wiley Sons, Inc.

Repeated three-dimensional magnetic resonance imaging of atherosclerosis development in innominate arteries of low-density lipoprotein receptor-knockout mice

Background-In vivo methods to evaluate the size and composition of atherosclerotic lesions in animal models of atherosclerosis would assist in the testing of antiatherosclerotic drugs. We have developed an MRI method of detecting atherosclerotic plaque in the major vessels at the base of the heart in low-density lipoprotein (LDL) receptor-knockout (LDLR-/-) mice on a high-fat diet. Methods and Results-Three-dimensional fast spin-echo magnetic resonance images were acquired at 7 T by use of cardiac and respiratory triggering, with approximate to140-mum isotropic resolution, over 30 minutes. Comparison of normal and fat-suppressed images from female LDLR-/- mice I week before and 8 and 12 weeks after the transfer to a high-fat diet allowed visualization and quantification of plaque development in the innominate artery in vivo. Plaque mean cross-sectional area was significantly greater at week 12 in the LDLR-/- mice (0.14+/-0.086 mm(2) [mean+/-SD]) than in wild-type control mice on a normal diet (0.017+/-0.031 mm(2), p

Determination of regional flow by use of intravascular PET tracers: Microvascular theory and experimental validation for pig livers

Today, the standard approach for the kinetic analysis of dynamic PET studies is compartment models, in which the tracer and its metabolites are confined to a few well-mixed compartments. We examine whether the standard model is suitable for modern PET data or whether theories including more physiologic realism can advance the interpretation of dynamic PET data. A more detailed microvascular theory is developed for intravascular tracers in single-capillary and multiple-capillary systems. The microvascular models, which account for concentration gradients in capillaries, are validated and compared with the standard model in a pig liver study. Methods: Eight pigs underwent a 5-min dynamic PET study after O-15-carbon monoxide inhalation. Throughout each experiment, hepatic arterial blood and portal venous blood were sampled, and flow was measured with transit-time flow meters. The hepatic dual-inlet concentration was calculated as the flow-weighted inlet concentration. Dynamic PET data were analyzed with a traditional single-compartment model and 2 microvascular models. Results: Microvascular models provided a better fit of the tissue activity of an intravascular tracer than did the compartment model. In particular, the early dynamic phase after a tracer bolus injection was much improved. The regional hepatic blood flow estimates provided by the microvascular models (1.3 +/- 0.3 mL min(-1) mL(-1) for the single-capillary model and 1.14 +/- 0.14 min(-1) mL(-1) for the multiple-capillary model) (mean +/- SEM mL of blood min(-1) mL of liver tissue(-1)) were in agreement with the total blood flow measured by flow meters and normalized to liver weight (1.03 +/- 0.12 mL min(-1) mL(-1)). Conclusion: Compared with the standard compartment model, the 2 microvascular models provide a superior description of tissue activity after an intravascular tracer bolus injection. The microvascular models include only parameters with a clear-cut physiologic interpretation and are applicable to capillary beds in any organ. In this study, the microvascular models were validated for the liver and provided quantitative regional flow estimates in agreement with flow measurements.

Measurement of muscle contraction with ultrasound imaging

To investigate the ability of ultrasonography to estimate musactivity, we measured architectural parameters (pennation angles, fascicle lengths, and muscle thickness) of several human muscles (tibialis anterior, biceps brachii, brachialis, transversus abdominis, obliquus internus abdominis, and obliquus externus abdominis) during isometric contractions of from 0 to 100% maximal voluntary contraction (MVC). Concurrently, electromyographic (EMG) activity was measured with surface (tibialis anterior only) or fine-wire electrodes. Most architectural parameters changed markedly with contractions up to 30% MVC but changed little at higher levels of contraction. Thus, ultrasound imaging can be used to detect low levels of muscle activity but cannot discriminate between moderate and strong contractions. Ultrasound measures could reliably detect changes in EMG of as little as 4% MVC (biceps muscle thickness), 5% MVC (brachialis muscle thickness), or 9% MVC (tibialis anterior pennation angle). They were generally less sensitive to changes in abdominal muscle activity, but it was possible to reliably detect contractions of 12% MVC in transversus abdominis (muscle length) and 22% MVC in obliquus internus (muscle thickness). Obliquus externus abdominis thickness did not change consistently with muscle contraction, so ultrasound measures of thickness cannot be used to detect activity of this muscle. Ultrasound imaging can thus provide a non-invasive method of detecting isometric muscle contractions of certain individual muscles.

A genetic algorithm/method of moments approach to the optimization of an RF coil for MRI applications - Theoretical considerations - Abstract

A Combined Genetic Algorithm and Method of Moments design methods is presented for the design of unusual near-field antennas for use in Magnetic Resonance Imaging systems. The method is successfully applied to the design of an asymmetric coil structure for use at 190MHz and demonstrates excellent radiofrequency field homogeneity.

Rates of electronic energy transfer in conformationally flexible bichromophoric macrocyclic complexes: a combined experimental and molecular modeling study

Electronic energy transfer (EET) rate constants between a naphthalene donor and anthracene acceptor in [ZnL4a](ClO4)(2) and [ZnL4b](ClO4)(2) were determined by time-resolved fluorescence where L-4a and L-4b are the trans and cis isomers of 6-((anthracen-9-yl-methyl)amino)-6,13-dimethyl-13-((naphthalen-1-yl-methyl)amino)-1,4,8,11-tetraazacyclotetradecane, respectively. These isomers differ in the relative disposition of the appended chromophores with respect to the macrocyclic plane. The trans isomer has an energy transfer rate constant (k(EET)) of 8.7 x 10(8) s(-1), whereas that of the cis isomer is significantly faster (2.3 x 10(9) s(-1)). Molecular modeling was used to determine the likely distribution of conformations in CH3CN solution for these complexes in an attempt to identify any distance or orientation dependency that may account for the differing rate constants observed. The calculated conformational distributions together with analysis by H-1 NMR for the [ZnL4a](2+) trans complex in the common trans-III N-based isomer gave a calculated Forster rate constant close to that observed experimentally. For the [ZnL4b](2+) cis complex, the experimentally determined rate constant may be attributed to a combination of trans-Ill and trans-I N-based isomeric forms of the complex in solution.

Portal do software p??blico brasileiro

O Portal do Software P??blico Brasileiro consolida-se como uma iniciativa que conseguiu criar um ambiente comum para compartilhar solu????es de software no setor p??blico, racionalizar a gest??o dos recursos de inform??tica, reaproveitar as solu????es de software existentes para diminuir custos e atividades redundantes, estabelecer parcerias e a????es cooperadas, refor??ar a pol??tica p??blica de estimular o uso de software livre e definir uma forma de licenciamento de software que sustente o compartilhamento de solu????es entre os ??rg??os do setor p??blico de acordo com as prerrogativas legais brasileiras e a Constitui????o Federal. Esta iniciativa trouxe como inova????o o compartilhamento de ???software p??blico???, que oficializou um novo modelo de licenciamento e de gest??o das solu????es desenvolvidas na administra????o p??blica, estabelecendo parceria entre diversos ??rg??os, institui????es, empresas e cidad??os, e hoje conta com mais de 100 mil participantes

Portal de peri??dicos da Capes

O Portal de Peri??dicos da Capes disponibiliza ??s institui????es de ensino superior e de pesquisa, conte??do atualizado e de alta qualidade permitindo consultas e acesso aos textos completos de artigos publicados em 23.925 revistas internacionais, nacionais e estrangeiras e mais de 124 bases de dados com resumos de documentos em todas as ??reas do conhecimento. Tem como finalidade oferecer ??s universidades, institutos de pesquisa e organiza????es governamentais, n??o governamentais e particulares, onde se desenvolve a p??sgradua????o e a pesquisa do pa??s, informa????o cient??fica necess??ria ?? forma????o de recursos humanos de alto n??vel e desenvolvimento do conhecimento, tecnologia e inova????o. O acesso ?? biblioteca eletr??nica se d?? via internet, por meio do site www.periodicos.capes.gov.br, de forma gratuita ??s organiza????es autorizadas. Em 2009, foram baixados mais de 65 milh??es de documentos, entre textos completos e abstracts

Portal corporativo da Escola Nacional de Sa??de P??blica Sergio Arouca, da Funda????o Oswaldo Cruz (Fiocruz)

O portal da ENSP foi criado como ferramenta de apoio ?? gest??o do conhecimento e para garantir a qualidade da informa????o gerada e organizada pela institui????o. Oferece um conjunto de aplicativos que consolida, gerencia, analisa e distribui informa????es, n??o s?? internamente, mas tamb??m para o p??blico externo. A integra????o desses aplicativos permite que os usu??rios possam ter um ??nico ponto de acesso ??s informa????es, permitindo ler, gravar e atualizar dados pessoais e institucionais. Nessa vers??o do portal da ENSP, os usu??rios devem-se cadastrar para ter acesso a alguns servi??os, como postagem de documentos na Biblioteca Multim??dia, coment??rios no Informe ENSP e participa????o em redes sociais, documentos internos e informa????es departamentais

Portal da transpar??ncia

O Portal da Transpar??ncia, criado em novembro de 2004, tem por objetivo promover a transpar??ncia da gest??o p??blica e estimular a participa????o e o controle social. O Portal viabiliza o acompanhamento efetivo da execu????o financeira de todos os programas e a????es do Governo Federal, em linguagem simples, navega????o amig??vel e sem necessidade de senhas, de modo que qualquer pessoa possa ter ampla no????o sobre como ?? aplicado o dinheiro p??blico. Est??o dispon??veis informa????es exatas, tempestivas e completas sobre recursos transferidos pelo Governo Federal aos outros entes p??blicos e diretamente ao cidad??o; gastos diretos realizados pelo Governo Federal em compras ou contrata????o de obras e servi??os; bem como gastos realizados por meio de cart??es de pagamentos do Governo Federal. O Portal da Transpar??ncia ?? hoje o mais abrangente banco de dados sobre os gastos do Governo Federal aberto a toda sociedade, representando, assim, iniciativa in??dita de transpar??ncia p??blica no Brasil e no mundo