Sertoli cells constitute the structural framework in testis and provide an immune-privileged environment for germ cells. Induced pluripotent stem cells (iPS cells) resemble embryonic stem cells (ES cells) and are generated from somatic cells by expression of specific reprogramming transcription factors. Here, we used C57BL/6 (B6) Sertoli cells to generate iPS cells (Ser-iPS cells) and compared the immunogenicity of Ser-iPS cells with iPS cells derived from mouse embryonic fibroblast (MEF-iPS cells). Ser-iPS cells were injected into syngeneic mice to test for their in vivo immunogenicity in teratoma assay. Teratoma assay allows assessing in vivo immunogenicity of iPS cells and of their differentiated progeny simultaneously. We observed that early-passage Ser-iPS cells formed more teratomas with less immune cell infiltration and tissue damage and necrosis than MEF-iPS cells. Differentiating Ser-iPS cells in embryoid bodies (EBs) showed reduced T cell activation potential compared to MEF-iPS cells, which was similar to syngeneic ES cells. However, Ser-iPS cells lost their reduced immunogenicity in vivo after extended passaging in vitro and late-passage Ser-iPS cells exhibited an immunogenicity similar to MEF-iPS cells. These findings indicate that early-passage Ser-iPS cells retain some somatic memory of Sertoli cells that impacts on immunogenicity of iPS cells and iPS cell-derived cells in vivo and in vitro. Our data suggest that immune-privileged Sertoli cells might represent a preferred source for iPS cell generation...

Copper oxide nanoparticles (CuONP) have attracted increasing attention due to their unique properties and have been extensively utilized in industrial and commercial applications. For example, their antimicrobial capability endows CuONP with applications in dressings and textiles against bacterial infections. Along with the wide applications, concerns about the possible effects of CuONP on humans are also increasing. It is crucial to evaluate the safety and impact of CuONP on humans, and especially the skin, prior to their practical application. The potential toxicity of CuONP to skin keratinocytes has been reported recently. However, the underlying mechanism of toxicity in skin cells has remained unclear. In the present work, we explored the possible mechanism of the cytotoxicity of CuONP in HaCaT human keratinocytes and mouse embryonic fibroblasts (MEF). CuONP exposure induced viability loss, migration inhibition, and G2/M phase cycle arrest in both cell types. CuONP significantly induced mitogen-activated protein kinase (extracellular signal-regulated kinase [Erk], p38, and c-Jun N-terminal kinase [JNK]) activation in dose- and time-dependent manners. U0126 (an inhibitor of Erk), but not SB 239063 (an inhibitor of p38) or SP600125 (an inhibitor of JNK)...

Chemotaxis is controlled by interactions between receptors, Rho-family GTPases, phosphatidylinositol 3-kinases, and cytoskeleton remodeling proteins. We investigated how the metastasis suppressor, SSeCKS, attenuates chemotaxis. Chemotaxis activity inversely correlated with SSeCKS levels in mouse embryo fibroblasts (MEF), DU145 and MDA-MB-231 cancer cells. SSeCKS loss induced chemotactic velocity and linear directionality, correlating with replacement of leading edge lamellipodia with fascin-enriched filopodia-like extensions, the formation of thickened longitudinal F-actin stress fibers reaching to filopodial tips, relative enrichments at the leading edge of phosphatidylinositol (3,4,5)P3 (PIP3), Akt, PKC-ζ, Cdc42-GTP and active Src (SrcpoY416), and a loss of Rac1. Leading edge lamellipodia and chemotaxis inhibition in SSeCKS-null MEF could be restored by full-length SSeCKS or SSeCKS deleted of its Src-binding domain (ΔSrc), but not by SSeCKS deleted of its three MARCKS (myristylated alanine-rich C kinase substrate) polybasic domains (ΔPBD), which bind PIP2 and PIP3. The enrichment of activated Cdc42 in SSeCKS-null leading edge filopodia correlated with recruitment of the Cdc42-specific guanine nucleotide exchange factor, Frabin...

MicroRNAs (miRNAs) are short 20–22 nucleotide RNA molecules that act as negative regulators of gene expression via translational repression: they have been shown to play a role in development, proliferation, stress response, and apoptosis. The transcriptional regulator LRF (Leukemia/lymphoma Related Factor) has been shown to prevent p19ARF transcription and consequently to inhibit senescence in mouse embryonic fibroblasts (MEF). Here we report, for the first time, that LRF is post-transcriptionally regulated by miR-20a. Using a gene reporter assay, direct interaction of miR-20a with the LRF 3′UTR is demonstrated. To validate the interaction miR-20a/3′UTR LRF miR-20a was over-expressed, either by transient transfection or retroviral infection, in wild type mouse embryo fibroblasts and in LRF-null MEF derived from LRF knock-out mice. We observed LRF decrease, p19ARF increase, inhibition of cell proliferation and induction of senescence. The comparison of miR-20a activity in wt and LRF-null MEF indicates that LRF is the main mediator of the miR-20a-induced senescence and that other targets are cooperating. As LRF down-regulation/p19ARF induction is always accompanied by E2F1 down-regulation and increase of p16, we propose that all these events act in synergy to accomplish miR-20a-induced senescence in MEF. Senescence has been recently revaluated as a tumor suppressor mechanism...

Objetivos: Através de revisão da literatura, avaliar as características gerais da manobra expiratória forçada (MEF) em crianças pré-escolares e a aplicação dos critérios de aceitação e reprodutibilidade testados nestes estudos. Por pesquisa original, avaliar a aceitação da MEF em crianças pré-escolares saudáveis em relação aos atuais critérios padronizados pela American Thoracic Society e European Respiratory Society (ATS/ERS, atualização 2005) e verificar o efeito de modificações nestes critérios, aceitando-se curvas com expiração incompleta; avaliar a reprodutibilidade da capacidade vital forçada (CVF), do volume expiratório forçado no primeiro segundo da CVF (VEF1) e do volume expiratório forçado na metade do primeiro segundo da CVF (VEF0,5), aos critérios já avaliados em outros estudos, de diferença ≤ 10% e ≤ 0,1 L, e, a um novo critério sugerido por estes autores, de diferença ≤ 8%. Métodos: Revisão da literatura nas bases de dados Medline, Scielo, Lilacs e Biblioteca Cockrane, de 1996 a março de 2006. Descritores: espirometria, testes de função pulmonar, capacidade vital forçada, valores de referência. Pesquisa por palavra: manobra, expiratória, forçada...

Orientador : Prof. Roberto Dalledone Machado; Co-orientador : Prof. Marcos Arndt; Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Métodos Numéricos em Engenharia. Defesa: Curitiba, 27/03/2014; Inclui referências; Área de concentração: Mecânica computacional; Resumo: O Método dos Elementos Finitos (MEF) é uma das ferramentas mais utilizadas na determinação dos modos e frequências naturais de vibração de uma estrutura, porém apresenta um problema de precisão com relação às frequências naturais de vibração mais altas de uma amostragem. Os Métodos de Enriquecimento do campo de funções do MEF surgiram com o intuito de melhorar os resultados originais. Se destacam o Método dos Modos Admissíveis (MMA), o Método Composto (MC), o Método dos Elementos Finitos p-Fourier (MEFF) e o Método dos Elementos Finitos Generalizados (MEFG). Recentemente surgiu um novo método numérico para resolução de equações diferenciais parciais denominado Análise Isogeométrica, a qual utiliza funções base do tipo NURBS (Non Uniform Rational B-Splines) como aproximadoras para a geometria do objeto em estudo e também como ponderação do problema analisado. Desde sua concepção algumas aplicações foram desenvolvidas para a análise dinâmica de estruturas e apresentaram resultados satisfatórios. O fenômeno de vibração livre de estruturas é definido e desenvolvido como um problema para múltiplos graus de liberdade. O MEF e os Métodos Enriquecidos são definidos e a Análise Isogeométrica (AIG) é apresentada em detalhes...

Magnetic nanoparticles (MNPs) have been used in a great variety of biomedical applications, especially in cancer treatment, drug delivery, and diagnosis by magnetic resonance imaging. Embryonic stem cells (ESCs), due to its capacity of auto-renewal and differentiation in some types of cells, offer a great potential for its use in tissue regeneration and in alternative treatments for many degenerative diseases. The study had as aims: i) to evaluate in vitro citotoxicity of maghemite nanoparticles functionalized with lauric acid, DMSA, and citrate in human melanoma cells (SK-MEL-37) by the MTT assay, electronic microscopy, and DNA electroforesis by agarose gel; ii) to develop a culture system using the previously selected MNPs and a magnet to expand in vitro murine embryonic stem cells (mESCs) in the absence of a co-culture of murine embryonic fibroblasts (MEF) (the indifferentiated state of the mES was analyzed by alkaline phosphatase cytochemistry, electronic microscopy, and analysis of Oct-4 and Nanog gene expression by RT-PCR); iii) to isolate and expand ESCs from bovine blastocysts, and to characterize its pluripotency by analysis of Oct-4 and STAT-3 gene expression by RT-PCR. The MNPs coated with lauric acid, citrate, and DMSA showed no citotoxicity...

O objetivo geral deste trabalho ´e o desenvolvimento de um sistema de workflows param´etricos para aplicac¸ ˜oes do m´etodo dos elementos finitos (MEF) em ambientes paralelos heterogˆeneos. Um workflow ´e um processo definido por um conjunto de atividades que executam sequencialmente e/ou em paralelo e que podem produzir, transformar ou consumir dados. O fluxo de execuc¸ ˜ao de um workflow ´e definido por canais que ligam uma porta de sa´ıda de uma atividade de origem a uma porta de entrada de outra atividade de destino. Por um canal podem trafegar dados ou um sinal de controle da atividade de origem `a de destino, indicando que a ´ultima pode iniciar sua execuc¸ ˜ao. Um workflow param´etrico ´e um modelo no qual uma ou mais atividades s˜ao argumentos de tipo do workflow. No sistema proposto, workflows podem ser gerados a partir de um workflow param´etrico definindo-se quais s˜ao os tipos de atividades correspondentes a cada um dos dos argumento de tipo do modelo. O sistema ´e escrito em C++ e constitu´ıdo de trˆes componentes principais: uma interface gr´afica atrav´es da qual o usu´ario pode interativamente criar, modificar, armazenar e executar workflows; um motor que atua como uma m´aquina virtual paralela respons´avel pela execuc¸ ˜ao de workflows; e uma biblioteca de atividades primitivas que representam os principais blocos b´asicos de construc¸ ˜ao de um programa...

O teste de push-out é largamente utilizado para avaliar a resistência adesiva de materiais no interior do canal radicular, determinando procedimentos clínicos e caracterizando materiais. Porém, seus parâmetros não estão bem estabelecidos na literatura. O objetivo desse trabalho foi avaliar a influência do diâmetro da ponta aplicadora de carga e do orifício central da base no desempenho do ensaio de push-out, por meio de ensaio laboratorial e método por elementos finitos (MEF). Três bases com diferentes diâmetros do orifício central (2,5; 3,0 e 3,5mm) e três pontas (0,5; 1,0 e 1,5mm) foram testadas. Para o ensaio laboratorial 90 raízes de incisivos bovinos retilíneas, com 15mm de comprimento e dimensões semelhantes foram utilizados. Estas foram preparados e restauradas com o pino de fibra de vidro White Post nº3 (FGM, Brasil) e RelyX Unicem (3M ESPE, USA). As raízes restauradas foram aleatoriamente divididas em nove grupos e duas fatias de 1 mm de espessura foram obtidas do terço cervical de cada uma. Todas as fatias foram analisadas em microscópio ótico e o maior e menor diâmetro do pino foi determinado por meio de software de medição digital para cálculo da área adesiva (mm²). Para realização do teste de push-out...

O estudo do comportamento de pontes ferrovi?rias vem tomando grande destaque na ?rea experimental, devido muitas das vezes haver a necessidade de um aumento dessas cargas m?veis. A companhia VALE a partir de um conv?nio estabelecido com a UFPA (Universidade Federal do Par?), buscou realizar estudos das capacidades resistentes das pontes ferrovi?rias, que comp?em a Estrada de Ferro Caraj?s (EFC), para futuros casos de carregamentos que passar?o de 32 tf para 40 tf, o que provoca mudan?as consider?veis no comportamento da estrutura. A falta de manuten??o ou uma manuten??o irregular das pontes de concreto armado podem resultar em manifesta??es patol?gicas que podem comprometer a seguran?a e ao risco de interven??o do escoamento. Dentre as OAE?s (Obras de Arte Especial) j? analisadas, encontra-se a ponte sobre o Rio M?e Maria localizada no munic?pio de Marab?, estado do Par?, transpondo o rio M?e Maria, identificada como OAE 50A, apresenta um tra?ado retil?neo executada em concreto armado moldada ?in loco?, ? constitu?da por dois v?os hiperest?ticos, totalizando 64,20 m, transpondo o leito do rio em dois v?os de 20 m e com se??o transversal oferecendo a largura de 5,85 m. Com isso tornou-se indispens?vel para avalia??o de sua integridade f?sica a monitora??o com extens?metros el?tricos de resist?ncia (EER) dos elementos (laje...

1. Mechanoelectric feedback (MEF) in the heart is the process by which mechanical forces on the myocardium can change its electrical properties. Mechanoelectric feedback has been demonstrated in many animal models, ranging from isolated cells, through isolated hearts to whole animals. In humans, MEF has been demonstrated directly in both the atria and the ventricles. It seems likely that MEF provides either the trigger or the substrate for some types of clinically important arrhythmias. 2. Mechanoelectric feedback may arise because of the presence of stretch-sensitive (or mechano-sensitive) ion channels in the cell membrane of the cardiac myocytes. Two types have been demonstrated: (i) a non-specific cation channel (stretch-activated channel (SAC); conductance of approximately 25 pS); and (ii) a potassium channel with a conductance of approximately 100 pS. The gene coding for the SAC has not yet been identified. The gene for the potassium channel is likely to be TREK, a member of the tandem pore potassium channel gene family. We have recorded stretch-sensitive potassium channels in rat isolated myocytes that have the properties of TREK channels expressed in heterologous systems. 3. It has been shown that TREK mRNA is expressed heterogeneously in the rat ventricular wall...

We upscaled FLUXNET observations of carbon dioxide, water, and energy fluxes to the global scale using the machine learning technique, model tree ensembles (MTE). We trained MTE to predict site‐level gross primary productivity (GPP), terrestrial ecosystem respiration (TER), net ecosystem exchange (NEE), latent energy (LE), and sensible heat (H) based on remote sensing indices, climate and meteorological data, and information on land use. We applied the trained MTEs to generate global flux fields at a 0.5° × 0.5° spatial resolution and a monthly temporal resolution from 1982 to 2008. Cross‐validation analyses revealed good performance of MTE in predicting among‐site flux variability with modeling efficiencies (MEf) between 0.64 and 0.84, except for NEE (MEf = 0.32). Performance was also good for predicting seasonal patterns (MEf between 0.84 and 0.89, except for NEE (0.64)). By comparison, predictions of monthly anomalies were not as strong (MEf between 0.29 and 0.52). Improved accounting of disturbance and lagged environmental effects, along with improved characterization of errors in the training data set, would contribute most to further reducing uncertainties. Our global estimates of LE (158 ± 7 J × 1018 yr−1), H (164 ± 15 J × 1018 yr−1)...

Este trabalho apresenta uma análise dos problemas físicos associados ao projeto de um sensor inercial giroscópio baseado na tecnologia MEMS (micro-electro-mechanical-system). O dispositivo oferece uma resposta elétrica na forma de uma variação da capacitância devido à força de Coriolis e como consequência obtém-se uma medida da velocidade angular de um sistema. Uma formulação analítica da dinâmica eletromecânica de um giroscópio com dois graus de liberdade é revista e implementada em um programa MATLAB/Simulink (R2011a) ®, onde são obtidas as respostas em deslocamento nos domínios do tempo e da frequência. Para melhorar a capacidade do projeto de sensores inerciais, uma abordagem da análise eletromecânica do giroscópio usando o Método dos Elementos Finitos (MEF) do programa comercial ANSYS 12.0® é apresentada. Neste contexto, dois projetos de giroscópios MEMS encontrados na literatura (giroscópio de ACAR e de NGUYEN) são analisados. Análises estática, modal e harmônica são realizadas e os resultados comparados com aqueles obtidos com os modelos analíticos. A resposta harmônica para o modelo eletromecânico completo de MEF não foi realizada devido à dificuldade de simular análises harmônicas incluindo os elementos de Atuação e Detecção simultaneamente. Para superar este problema o elemento Detector foi substituído por um elemento de mola. Os resultados obtidos no giroscópio de NGUYEN apresentaram boa concordância entre os modelos. Contudo...

Tese de mestrado, Psicologia (Secção de Psicologia Clínica e da Saúde - Núcleo de Psicologia Clínica Sistémica), Universidade de Lisboa, Faculdade de Psicologia, 2012; O presente estudo pretende avaliar o impacto de um programa de prevenção de perturbações alimentares na adolescência – “ Alimentacíon, modelo estético feminino y medios de comunicación. Cómo formar alunos críticos en educación secundaria.” – relativamente a variáveis individuais, tais como atividade física, IMC e insatisfação com a imagem corporal e socioculturais consideradas de risco para o desenvolvimento de comportamentos alimentares perturbados. A amostra é constituída por quarenta adolescentes de ambos os sexos a frequentar o 8º ano escolaridade, distribuídos por duas condições experimentais distintas: Modelo Estético Feminino + Media Literacy (MEF+ML) e Alimentação e Nutrição (NUT). Os participantes responderam a um protocolo em três momentos distintos (pré-teste, pós-teste e follow-up a um mês) para avaliar o impacto do programa. Este protocolo era constituído por um questionário de dados pessoais e sociodemográficos, o Eating Attitudes Test-26 (Garner, Olmsted, Bohr & Garfinkel, 1982), a Contour Drawing Rating Scale (Thompson & Gray...

Obesity is a chronic inflammation with increased serum levels of insulin, insulin-like growth factor 1 (IGF1), and interleukin-17 (IL-17). The objective of this study was to test a hypothesis that insulin and IGF1 enhance IL-17-induced expression of inflammatory chemokines/cytokines through a glycogen synthase kinase 3β (GSK3B)-dependent mechanism, which can be inhibited by melatonin. We found that insulin/IGF1 and lithium chloride enhanced IL-17-induced expression of C-X-C motif ligand 1 (Cxcl1) and C-C motif ligand 20 (Ccl20) in the Gsk3b+/+ but not Gsk3b−/− mouse embryonic fibroblast (MEF) cells. IL-17 induced higher levels of Cxcl1 and Ccl20 in the Gsk3b−/− MEF cells, compared to the Gsk3b+/+ MEF cells. Insulin and IGF1 activated Akt to phosphorylate GSK3B at serine 9, thus inhibiting GSK3B activity. Melatonin inhibited Akt activation, thus decreasing P-GSK3B at serine 9 (i.e., increasing GSK3B activity) and subsequently inhibiting expression of Cxcl1 and Ccl20 that was induced either by IL-17 alone or by a combination of insulin and IL-17. Melatonin's inhibitory effects were only observed in the Gsk3b+/+ but not Gsk3b−/− MEF cells. Melatonin also inhibited expression of Cxcl1, Ccl20 and Il-6 that was induced by a combination of insulin and IL-17 in the mouse prostatic tissues. Further...

The focal adhesion protein vinculin (1066 residues) can be separated into a 95-kDa head and a 30-kDa tail domain. Vinculin's lipid binding sites localized on the tail, helix 3 (residues 944–978) and the unstructured C-terminal arm (residues 1052–1066, the so-called lipid anchor), influence focal adhesion turnover and are important for cell migration and adhesion. Using magnetic tweezers, we characterized the cell mechanical behavior in mouse embryonic fibroblast (MEF)-vin(−/−) cells transfected with EGFP-linked-vinculin deficient of the lipid anchor (vinΔC, residues 1–1051). MEF-vinΔC cells incubated with fibronectin-coated paramagnetic beads were less stiff, and more beads detached during these experiments compared to MEF-rescue cells. Cells expressing vinΔC formed fewer focal contacts as determined by confocal microscopy. Two-dimensional traction measurements showed that MEF-vinΔC cells generate less force compared to rescue cells. Attenuated traction forces were also found in cells that expressed vinculin with point mutations (R1060 and K1061 to Q) of the lipid anchor that impaired lipid binding. However, traction generation was not diminished in cells that expressed vinculin with impaired lipid binding caused by point mutations on helix 3. Mutating the src-phosphorylation site (Y1065 to F) resulted in reduced traction generation. These observations show that both the lipid binding and the src-phosphorylation of vinculin's C-terminus are important for cell mechanical behavior.

A pesar de que un cable es un elemento estructural diseñado esencialmente para transmitir cargas de tracción, su geometría helicoidal es tal que los componentes que lo forman no sólo desarrollan esfuerzos de tracción sino que también esfuerzos de flexión, corte, torsión, fricción y fuerzas de contacto. Ante la acción de cargas axisimétricas, la magnitud y distribución de las tensiones resultantes en los componentes de un cable determinan el comportamiento de éste, el cual puede ser expresado en términos de su elongación y rotación axial. Este trabajo de título tiene dos objetivos principales: (1) validar y analizar las limitaciones de modelos matemáticos discretos 2D desarrollados para predecir el comportamiento de cables sometidos a cargas axisimétricas; y (2) estudiar el efecto del daño simétrico y asimétrico en la magnitud y distribución de los esfuerzos internos y en la respuesta global (rigidez, capacidad máxima y deformación de falla) del cable cuando es solicitado por cargas axisimétricas. En este estudio se entiende por daño en un cable a que elemento(s) de éste presenta(n) discontinuidad en su longitud en una o varias secciones del cable. Para alcanzar los objetivos planteados se utiliza una modelación del cable 3D en base al método de Elementos Finitos (MEF) utilizando el programa ANSYS...

Exploiting 2D materials for spintronic applications can potentially realize next-generation devices featuring low-power consumption and quantum operation capability. The magnetic exchange field (MEF) induced by an adjacent magnetic insulator enables efficient control of local spin generation and spin modulation in 2D devices without compromising the delicate material structures. Using graphene as a prototypical 2D system, we demonstrate that its coupling to the model magnetic insulator (EuS) produces a substantial MEF (> 14 T) with potential to reach hundreds of Tesla, which leads to orders-of-magnitude enhancement in the spin signal originated from Zeeman spin-Hall effect. Furthermore, the new ferromagnetic ground state of Dirac electrons resulting from the strong MEF may give rise to quantized spin-polarized edge transport. The MEF effect shown in our graphene/EuS devices therefore provides a key functionality for future spin logic and memory devices based on emerging 2D materials in classical and quantum information processing.

Very recently, Verlinde considered a theory in which space is emergent through a holographic scenario, and proposed that gravity can be explained as an entropic force caused by changes in the information associated with the positions of material bodies. Then, motivated by the Debye model in thermodynamics which is very successful in very low temperatures, Gao modified the entropic force scenario. The modified entropic force (MEF) model is in fact a modified gravity model, and the universe can be accelerated without dark energy. In the present work, we consider the cosmological constraints on the MEF model, and successfully constrain the model parameters to a narrow range. We also discuss many other issues of the MEF model. In particular, we clearly reveal the implicit root to accelerate the universe in the MEF model.; Comment: 16 pages, 7 figures, revtex4; v2: discussions added, Phys. Lett. B in press; v3: published version

In metal-enhanced fluorescence (MEF), the localized surface plasmon resonances of metallic nanostructures amplify the absorption of excitation light and assist in radiating the consequent fluorescence of nearby molecules to the far-field. This effect is at the base of various technologies that have strong impact on fields such as optics, medical diagnostics and biotechnology. Among possible emission bands, those in the near-infrared (NIR) are particularly intriguing and widely used in proteomics and genomics due to its noninvasive character for biomolecules, living cells, and tissues, which greatly motivates the development of effective, and eventually multifunctional NIR-MEF platforms. Here we demonstrate NIR-MEF substrates based on Au nanocages micropatterned with a tight spatial control. The dependence of the fluorescence enhancement on the distance between the nanocage and the radiating dipoles is investigated experimentally and modeled by taking into account the local electric field enhancement and the modified radiation and absorption rates of the emitting molecules. At a distance around 80 nm, a maximum enhancement up to 2-7 times with respect to the emission from pristine dyes (in the region 660 nm-740 nm) is estimated for films and electrospun nanofibers. Due to their chemical stability...