600 research outputs found

    Buckling analysis of laminated anisotropic kirchhoffs plates via the boundary element method

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    A new fundamental solution for laminated anisotropic Kirchhoff’s plates with out-of-plane and in-plane compressive loads is derived here. The multicompressed solution for both isotropic and anisotropic cases is obtained via the Radon Transform. Some fundamental kernels of the integral equations are described in detail. BEM results of displacements and critical buckling loads of several plates with different boundary conditions and geometries are presented. Comparisons with available analytical solutions and some published numerical results confirm the reliability and accuracy of the proposed formulation151

    Biochemical diagnosis of medullary thyroid carcinoma: basal calcitonin and provocative tests

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    Calcitonin is a hormone secreted by the parafollicular thyroid cells. Diagnosis of medullary thyroid carcinoma (MTC) should be considered when high basal calcitonin levels or high calcitonin levels after specific provocative test are found. In this context, calcitonin is considered a relevant tumor marker for diagnosis and follow-up of MTC. In this manuscript, we review some issues related to the usefulness of measuring basal calcitonin in patients with thyroid nodules. The current available provocative tests for calcitonin are discussed. Finally, we comment on some aspects related to the assays for calcitonin measurement.A calcitonina é um hormônio secretado pelas células parafoliculares tiroideanas. O diagnóstico de carcinoma medular de tiróide (CMT) pode ser suspeitado a partir do encontro de níveis aumentados de calcitonina basal ou após testes de estímulos específicos. Neste sentido, a calcitonina caracteriza-se como um importante marcador tumoral para o diagnóstico e seguimento de pacientes portadores de CMT. Neste artigo, revisamos alguns tópicos referentes à utilidade da dosagem de calcitonina basal em pacientes portadores de nódulos de tiróide para rastreamento de CMT. Comentamos a respeito dos principais testes de estímulo para secreção de calcitonina disponíveis e finalizamos com algumas observações sobre os ensaios para dosagem de calcitonina.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Fleury - Centro de Medicina DiagnósticaUNIFESP, EPM, Fleury - Centro de Medicina DiagnósticaSciEL

    Electron-Electron Bound States in Maxwell-Chern-Simons-Proca QED3

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    We start from a parity-breaking MCS QED3_{3} model with spontaneous breaking of the gauge symmetry as a framework for evaluation of the electron-electron interaction potential and for attainment of numerical values for the e-e bound state. Three expressions are obtained for the potential according to the polarization state of the scattered electrons. In an energy scale compatible with Condensed Matter electronic excitations, these three potentials become degenerated. The resulting potential is implemented in the Schrodinger equation and the variational method is applied to carry out the electronic binding energy. The resulting binding energies in the scale of 10-100 meV and a correlation length in the scale of 10-30 Angs. are possible indications that the MCS-QED3_{3} model adopted may be suitable to address an eventual case of e-e pairing in the presence of parity-symmetry breakdown. The data analyzed here suggest an energy scale of 10-100 meV to fix the breaking of the U(1)-symmetry. PACS numbers: 11.10.Kk 11.15.Ex 74.20.-z 74.72.-h ICEN-PS-01/1

    Anti-thyroid antibodies: methodological aspects and diagnostic significance

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    Since the first publication, more than 40 years ago, laboratory tests for the presence of antibodies (Ab) to thyroid antigens (Ag) have played a pivotal position in the diagnosis of thyroid diseases. Thyroid is a common target for autoimmune diseases, hence the interest in the definition of the thyroid Ag that could be involved in the process. The first Ag to be recognized was thyroglobulin, followed by the microsomal Ag, later identified with thyroid peroxidase, the TSH receptor and, more recently, other Ag like the sodium/iodide symporter (NIS). The methodologies employed evolved from the initial hemaglutination assays, to the present use of recombinant Ag, alternative labels and transfected cells. Today the clinical uses of a test to detect the presence of Ab against thyroid Ag are very well defined. The most useful test is the detection of anti-peroxidase Ab, the test with greatest sensitivity and specificity for the presence of autoimmune thyroid diseases. The anti-thyroglobulin test is mandatory as a complement for the measurement of thyroglobulin in the follow-up of patients with differentiated thyroid cancers. The anti-TSH receptor test has its main use in the definition of the presence of Graves disease. Tests for the presence of Ab against other thyroid Ag have no clear indication at the moment. The continuous methodological developments will certainly increase the utility of tests for anti-thyroid Ab.Desde sua descrição, há mais de 40 anos, a pesquisa de anticorpos (Ac) contra antígenos (Ag) tiroideanos tem tido papel importante no diagnóstico da patologia tiroideana. A tiróide é freqüentemente acometida por doenças autoimunes, daí o interesse pela definição dos Ag tiroideanos que podem estar envolvidos no processo. O primeiro Ag reconhecido foi a tireoglobulina, seguido do fator microssomal, mais tarde identificado como a peroxidase tiroideana, o receptor de TSH e mais recentemente outros Ag como o cotransportador de sódio e iodo (sodium/iodide symporter, NIS). As metodologias evoluíram dos ensaios iniciais por hemaglutinação até o emprego atual de Ag recombinantes, marcadores alternativos e células transfectadas. Atualmente as indicações clínicas da pesquisa de Ac anti-tiroideanos são bem definidas, sendo o de maior aplicação a pesquisa de Ac anti-peroxidase, que é o que apresenta maior especificidade e sensibilidade para a definição da presença de doença autoimune tiroideana. A pesquisa de Ac anti-tireoglobulina é fundamental como complemento da dosagem de tireoglobulina no acompanhamento de pacientes com carcinoma diferenciado de tiróide. Já a pesquisa de Ac anti-receptor de TSH tem indicação precisa na definição da presença de doença de Graves. As indicações de pesquisa de Ac contra outros Ag tiroideanos não têm, atualmente, indicações comprovadas. A contínua evolução metodológica deverá aumentar ainda mais as indicações e utilidades da pesquisa de Ac contra Ag tiroideanos.Universidade Federal de São Paulo (UNIFESP) EPM Departamento de MedicinaUNIFESP, EPM, Depto. de MedicinaSciEL

    U-Pb zircon geochronology, geochemistry, and petrogenesis of the Hamech intrusions in the Kuh-e-Shah volcano-plutonic complex, Eastern Iran

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    The Hamech area is located in the west of Kuh-e-Shah volcano-plutonic complex, close to the boundary between the Lut Block and Sistan Suture Zone (SSZ), and is composed of monzonite to diorite porphyries and rare gabbro that intruded into older volcanic rocks. U-Pb zircon dating indicates an age of 36.9 ± 1 Ma for gabbro (Late Eocene, Priabonian) and 38.6 ± 0.5 Ma for dacite (Late Eocene, Bartonian). Geochemically, the studied intrusions are dominantly I-type, high-K calc-alkaline, and metaluminous features. Primitive mantle-normalized trace-element spider diagrams of these rocks present enrichment in ion lithophile elements such as Cs, Rb, Ba, K, and Sr and depletion in high field strength elements such as Nb, Ti, Zr, and heavy rare earth elements. Besides, chondrite-normalized rare earth elements plots of the rocks show enrichment in light rare earth elements (6.85 < LaN/YbN < 9.72) and a lack or weak negative Eu anomaly (Eu/Eu* = 0.81–1.02). The initial 87Sr/86Sr and 143Nd/144Nd ratios for the rocks from 0.704541 to 0.704880 and from 0.512633 to 0.512691, respectively, when recalculated to an age of 39 Ma. The εNd(i) values vary from +0.87 to +1.99, which fits into a suprasubduction mantle wedge source for the parental melts. All data suggest that the Hamech intrusions developed in a low maturity continental margin arc setting related to the convergence of the Afghan and Lut Blocks and subduction of Sistan oceanic crust during the Eocene.publishe
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