Arbitrary order 2D virtual elements for polygonal meshes: Part II, inelastic problem

The present paper is the second part of a twofold work, whose first part is reported in [3], concerning a newly developed Virtual Element Method (VEM) for 2D continuum problems. The first part of the work proposed a study for linear elastic problem. The aim of this part is to explore the features of the VEM formulation when material nonlinearity is considered, showing that the accuracy and easiness of implementation discovered in the analysis inherent to the first part of the work are still retained. Three different nonlinear constitutive laws are considered in the VEM formulation. In particular, the generalized viscoplastic model, the classical Mises plasticity with isotropic/kinematic hardening and a shape memory alloy (SMA) constitutive law are implemented. The versatility with respect to all the considered nonlinear material constitutive laws is demonstrated through several numerical examples, also remarking that the proposed 2D VEM formulation can be straightforwardly implemented as in a standard nonlinear structural finite element method (FEM) framework

HIV-1 gp120 influences the expression of microRNAs in human monocyte-derived dendritic cells via STAT3 activation

Background: MicroRNAs (miRs) are an abundant class of small non-coding RNAs (~22 nt) that reprogram gene ex- pression by targeting mRNA degradation and translational disruption. An emerging concept implicates miR coup- ling with transcription factors in myeloid cell development and function, thus contributing to host defense and inflammation. The important role that these molecules play in the pathogenesis of HIV-1 is only now emerging. Results: We provide evidence that exposure of monocyte-derived dendritic cells (MDDCs) to recombinant HIV-1 R5 gp120, but not to CCR5 natural ligand CCL4, influences the expression of a panel of miRs (i.e., miR-21, miR-155 and miR-181b) regulated by STAT3 and potentially targeting genes belonging to the STAT3 signaling pathway. The blockage of gp120-induced STAT3 activation impairs gp120 capacity to modulate the expression level of above mentioned miRs. Predictive analysis of miR putative targets emphasizes that these miRs share common target genes. Furthermore, gene ontology and pathway enrichment analysis outline that these genes mainly belong to biological processes related to regulation of transcription, in a complex network of interactions involving pathways relevant to HIV-DC interaction. Conclusions: Overall, these results point to gp120-triggered modulation of miR expression via STAT3 activation as a novel molecular mechanism exploited by HIV-1 to affect DC biology and thus modulate the immune response through complex regulatory loops involving, at the same time, miRs and transcription factors

Computational Challenges in miRNA Target Predictions: To Be or Not to Be a True Target?

All microRNA (miRNA) target—finder algorithms return lists of candidate target genes. How valid is that output in a biological setting? Transcriptome analysis has proven to be a useful approach to determine mRNA targets. Time course mRNA microarray experiments may reliably identify downregulated genes in response to overexpression of specific miRNA. The approach may miss some miRNA targets that are principally downregulated at the protein level. However, the high-throughput capacity of the assay makes it an effective tool to rapidly identify a large number of promising miRNA targets. Finally, loss and gain of function miRNA genetics have the clear potential of being critical in evaluating the biological relevance of thousands of target genes predicted by bioinformatic studies and to test the degree to which miRNA-mediated regulation of any “validated” target functionally matters to the animal or plant

Quantification of Small Non-Coding RNAs Allows an Accurate Comparison of miRNA Expression Profiles

MicroRNAs (miRNAs) are highly conserved ∼22-mer RNA molecules, encoded by plants and animals that regulate the expression of genes binding to the 3′-UTR of specific target mRNAs. The amount of miRNAs in a total RNA sample depends on the recovery efficiency that may be significantly affected by the different purification methods employed. Traditional approaches may be inefficient at recovering small RNAs, and common spectrophotometric determination is not adequate to quantify selectively these low molecular weight (LMW) species from total RNA samples. Here, we describe the use of qualitative and quantitative lab-on-a-chip tools for the analysis of these LMW RNA species. Our data emphasize the close correlation of LMW RNAs with the expression levels of some miRNAs. We therefore applied our result to the comparison of some miRNA expression profiles in different tissues. Finally, the methods we used in this paper allowed us to analyze the efficiency of extraction protocols, to study the small (but significant) differences among various preparations and to allow a proper comparison of some miRNA expression profiles in various tissues

BIOMECHANICAL APPROACH TO BALLET MOVEMENTS: A STUDY OF THE EFFECTS OF BALLET SHOE AND MUSICAL BEAT ON THE VERTICAL REACTION FORCES

Ballet movements can be the focus of biomechanical studies in order to better understand the characteristic mechanical loads of the locomotor apparatus related to classic dance. "Pointe shoes" have been associated to high incidence of morphological and physiological alterations of ballet dancer's feet, however its contribution to injury mechanisms must still be precisely known. On the other hand, movements like jumps and leaps are frequently repeated in a standard ballet training, where the musical beat also plays a role on the motor behavior and its mechanical aspects. Therefore the purpose of the present study was to describe ground reaction forces during the "saute -1st position" under the influence of footwear (slippers and pointe shoes) and musical beat in order to identify the relative contribution of these factors on the external loads measured. It was observed that the musical beat played a greater role on the ground reaction force magnitudes than the footwear

BIOMECHANICAL APPROACH TO BALLET MOVEMENTS: A PRELIMINARY STUDY

Movements in ballet dance often involve extreme joint positions and muscular efforts that may exceed normal ranges of motion and generate high stresses on bone and soft tissues. The primary aim of this study was to apply the principles and techniques of biomechanics to study ballet movements. Ground reaction forces and plantar pressure distribution were registered with a Kistler Platform and a Tekscan Systems respectively. Knee joint action in the sagittal plane was simultaneously collected with an electrogoniometer. Peak vertical forces, peak pressures and knee flexion-extension were analyzed and discussed. A better understanding of these biomechanical aspects may lead to a decrease of the injury risks and also to more graceful and efficient dance movements

Estudo da distribuição das pressões plantares em crianças obesas: efeitos de um programa de intervenção

A condição de obesidade está associada com riscos à integridade estrutural e funcional de membros inferiores e as medidas de pressão plantar são ferramentas importantes para avaliar tais riscos. O estudo teve como objetivo analisar o efeito de um programa de intervenção multidisciplinar para o controle da obesidade sobre o comportamento da distribuição das pressões plantares em crianças obesas. Foram avaliadas 20 crianças, divididas em dois grupos (grupo experimental e grupo controle), de ambos os sexos, com idades entre nove e 11 anos. Os dados foram coletados antes e depois de um período de intervenção, que teve duração de três meses. As avaliações incluíram medidas das variáveis de pressão plantar, em seis áreas anatômicas dos pés, na postura ereta e na marcha por meio do sistema Pedar (Novel, GMbH). A partir dos resultados obtidos constatou-se que a massa corporal está minimamente correlacionada com a pressão plantar, o que pode explicar, parcialmente, a ausência de efeitos do programa especificamente delineado para este estudo sobre as variáveis selecionadas. Especula-se, porém, que modificações na distribuição das pressões plantares iniciem-se na região do médio-pé. Dessa forma, recomenda-se que programas de intervenção sejam associados ao treino das funções estáticas e dinâmicas dos pés, a fim de promover modificações importantes no comportamento das pressões plantares e, dessa forma, prevenir prejuízos aos pés de crianças obesas.The obesity condition is associated with risks to structural and functional integrity of the lower limbs. Plantar pressure measure is an important tool to evaluate these risks. The purpose of this study was to assess the effect of a multidisciplinary intervention program on the plantar pressure distributions in obese children. Twenty children aged 9 to 11 years were divided into two groups (experimental group and control group). The data were collected before and after a three month intervention period. The evaluations included plantar pressure variables under six areas of the foot during standing and walking using the Pedar system (Novel, GMbH). The results revealed that the body mass presented low correlations with the plantar pressures, what can partially explain the lack of effect of this intervention program on the selected variables. It is speculated, however, that changes on the plantar pressure distribution begin under the midfoot region. Thus, intervention programs associated with training of the static and dynamic foot function are recommended, in order to promote important modifications in the plantar pressure behavior and, consequently, to prevent damage to the obese children's feet

Cooperativismo e inclusão social: o caso dos mercados institucionais no Sul do Brasil

It was in the interior of Rio Grande do Sul that Brazil's first cooperatives emerged. However, it was also in this state that the emergence of business cooperatives, economic organizations that grew during the 1960s and 1980s, thanks to the generous subsidies of the authoritarian state (1964-1985), is witnessing. The economic crisis unleashed during and after the 1980s - the lost decade - shook the foundations of business cooperativism and the principles of this economic and social doctrine. This article focuses on a completely different reality, namely, that of small family farming cooperatives located in the southern tip of Brazil whose emergence is inextricably linked to the implementation of food security policies, especially through institutional purchases led by public entities, example of the School-Restaurant of the Federal University of Pelotas. Such a system proves to be efficient both from the point of view of ensuring that demand is met and of promoting the social inclusion of rural families that are part of the cooperatives' membership. However, this process is interrupted due to the bureaucratic impositions of the federal control bodies, a fact that generates uncertainty and discouragement for the actors involved in this process. Meanwhile, there remains recognition of the virtues of cooperativism as a way to reconcile economic development with social justice and to encourage innovation, learning and convergence around common interests and goals. The aim of the article is to reflect on this experience in the light of concrete reality. This approach was based on a qualitative methodology whose emphasis was in depth interviews with a semi-structured script applied to various social actors, especially leaders and producers who work in cooperatives linked to institutional markets. Keywords: Food security. Family farming. Cooperativism. Institutional Markets.Fue en el interior de Rio Grande do Sul que surgieron las primeras cooperativas de Brasil. Sin embargo, es también en este estado brasileño que se asiste a la emergencia de las cooperativas empresariales, unas estructuras económicas que se agigantaron durante las décadas de 1960 y 1980 a raíz de las generosas subvenciones del Estado autoritario (1964-1985). La crisis económica acaecida durante y después de los años 1980- la llamada década perdida – afectó los fundamentos del cooperativismo empresarial y los pilares elementares de esta doctrina económica y social. El presente artículo aborda una realidad completamente distinta, cual sea, la de pequeñas cooperativas de agricultura familiar ubicadas en el extremo meridional cuya aparición está ligada a la implantación de políticas de seguridad alimentaria, sobre todo a través de las compras institucionales capitaneadas por entes públicos, sobre todo de los comedores de la Universidade Federal de Pelotas. Tal sistema se mostró eficiente tanto del punto de vista de atender la demanda como de promover la inclusión social de las familias que integran el cuadro social de las cooperativas. Sin embargo, tal ciclo se interrumpe a causa de las imposiciones burocráticas de los órganos de control, hecho que causa incertidumbre y desaliento para los actores implicados en este proceso. Todavia, resta la convicción sobre las virtudes del cooperativismo como camino para conciliar desarrollo económico y justicia social, así como para generar innovación, aprendizaje y convergencia en torno a intereses y objetivos comunes. El objetivo del artículo ha sido reflexionar sobre dicha experiencia bajo la perspectiva de la realidad concreta. Tal aproximación se dio a partir de metodología cualitativa, cuya  énfasis recae sobre entrevistas en profundidad y guión semiestructurado aplicadas junto a diversos actores sociales, especialmente junto a dirigentes y productores que actuan en las cooperativas ligadas a los mercados institucionales. Palabras-clave: Seguridad alimentaria. Agricultura familiar. Cooperativismo. Mercados Institucionales.Foi no interior do Rio Grande do Sul que surgiram as primeiras cooperativas do Brasil. Não obstante, é também nesse estado que se assiste à emergência das cooperativas empresariais, organizações econômicas que se agigantaram, durante as décadas de 1960 e 1980, graças aos generosos subsídios do Estado autoritário (1964-1985). A crise econômica desencadeada durante e depois dos anos 1980 – a década perdida – abalou os fundamentos do cooperativismo empresarial e os princípios desta doutrina econômica e social. O presente artigo se debruça sobre uma realidade completamente distinta, qual seja, a de pequenas cooperativas de agricultura familiar situadas no extremo meridional do Brasil cujo surgimento está inextricavelmente ligado à implantação das políticas de segurança alimentar, mormente pelas compras institucionais capitaneadas por entes públicos, a exemplo do Restaurante-Escola da Universidade Federal de Pelotas. Tal sistema se mostra eficiente tanto do ponto de vista de assegurar o atendimento da demanda como no sentido de promover a inclusão social das famílias rurais que integram o quadro social das cooperativas. Todavia, tal processo é interrompido por força das imposições burocráticas dos órgãos federais de controle, fato que gera incertezas e desalento para os atores implicados nesse processo. Entrementes, resta o reconhecimento sobre as virtudes do cooperativismo como caminho para conciliar desenvolvimento econômico com justiça social e de incentivar a inovação, a aprendizagem e a convergência em torno a interesses e objetivos comuns. O objetivo do artigo é fazer uma reflexão sobre essa experiência à luz da realidade concreta. Tal aproximação se deu a partir de metodologia qualitativa cuja ênfase foram entrevistas com roteiro semiestruturado aplicadas junto a diversos atores sociais, especialmente de lideranças e produtores que atuam nas cooperativas ligadas aos mercados institucionais. Palavras-chave: Segurança alimentar. Agricultura familiar. Cooperativismo. Mercados Institucionais