Análise não-linear de estruturas laminares pelo método dos elementos finitos

ln this work, the finite element method is applied to problems involving the geometrically non-linear behaviour of surface structures, subjected to static and dynamic loads. Two kinds of formulations are studied. ln the first one, through isoparametric degenerated elements, the tridimensional theory of elasticity is directly used. There are no restrictions for the magnitude of the deformations. The other one, derived from the von Kármán strain expressions for large deflections of thin plates, is limited to problems involving small deformations. Results from several analysis are presented. Advantages and limitations of the developed aproximations are discussed, as well as the efficiency of the implemented models.Neste trabalho, aplica-se o método dos elementos finitos à análise do comportamento não-linear geométrico de estruturas laminares, sob ação de cargas estáticas e dinâmicas. Dois tipos de formulação são estudadas. Na primeira, através de elementos degenerados de elementos isoparamétricos, utiliza-se diretamente a teoria da elasticidade tridimensional, não introduzindo restrições quanto à grandeza das deformações. A outra, derivada das equações de von Kármán para grandes deflexões de estruturas delgadas, é específica para problemas de pequenas deformações. Resultados de diversas análises são apresentados. Discutem-se vantagens e limitações das aproximações desenvolvidas e eficiência dos modelos implementados

A double-blind, randomized, comparative study of the use of a combination of uridine triphosphate trisodium, cytidine monophosphate disodium, and hydroxocobalamin, versus isolated treatment with hydroxocobalamin, in patients presenting with compressive neuralgias

CONTEXT: This paper reports on the results of treatment of compressive neuralgia using a combination of nucleotides (uridine triphosphate trisodium [UTP] and cytidine monophosphate disodium [CMP]) and vitamin B(12). OBJECTIVES: To assess the safety and efficacy of the combination of nucleotides (UTP and CMP) and vitamin B(12) in patients presenting with neuralgia arising from neural compression associated with degenerative orthopedic alterations and trauma, and to compare these effects with isolated administration of vitamin B(12). METHODS: A randomized, double-blind, controlled trial, consisting of a 30-day oral treatment period: Group A (n=200) receiving nucleotides + vitamin B(12,) and Group B (n=200) receiving vitamin B(12) alone. The primary study endpoint was the percentage of subjects presenting pain visual analog scale (VAS) scores ≤20 at end of study treatment period. Secondary study endpoints included the percentage of subjects presenting improvement ≥5 points on the patient functionality questionnaire (PFQ); percentage of subjects presenting pain reduction (reduction in VAS scores at study end in relation to pretreatment); and number of subjects presenting adverse events. RESULTS: The results of this study showed a more expressive improvement in efficacy evaluations among subjects treated with the combination of nucleotides + vitamin B(12), with a statistically significant superiority of the combination in pain reduction (evidenced by VAS scores). There were adverse events in both treatment groups, but these were transitory and no severe adverse event was recorded during the study period. Safety parameters were maintained throughout the study in both treatment groups. CONCLUSION: The combination of uridine, cytidine, and vitamin B(12) was safe and effective in the treatment of neuralgias arising from neural compression associated with degenerative orthopedic alterations and trauma

A prenylated dsRNA sensor protects against severe COVID-19

Inherited genetic factors can influence the severity of COVID-19, but the molecular explanation underpinning a genetic association is often unclear. Intracellular antiviral defenses can inhibit the replication of viruses and reduce disease severity. To better understand the antiviral defenses relevant to COVID-19, we used interferon-stimulated gene (ISG) expression screening to reveal that OAS1, through RNase L, potently inhibits SARS-CoV-2. We show that a common splice-acceptor SNP (Rs10774671) governs whether people express prenylated OAS1 isoforms that are membrane-associated and sense specific regions of SARS-CoV-2 RNAs, or only express cytosolic, nonprenylated OAS1 that does not efficiently detect SARS-CoV-2. Importantly, in hospitalized patients, expression of prenylated OAS1 was associated with protection from severe COVID-19, suggesting this antiviral defense is a major component of a protective antiviral response

Potential and viscous flow problems using the boundary element method

This work is concerned with the application of the Boundary Element Method for the solution of steady and transient potential and viscous flow problems. Two-dimensional, axisymmetric and fully three-dimensional problems are considered, the general theory developed and specific numerical procedures derived for each of the above cases.Initially, the derivation of the boundary integral equation equivalent to Laplace's equation is reviewed within the framework of classical potential theory. Numerical procedures for the solution of this equation are discussed, the boundary being discretised by using piecewise constant, linear or quadratic variations for the potential function and its normal derivative.Integral formulations for the solution of the diffusion equationare then studied. Three different approaches are considered: using Laplace transforms, coupling the BEM with the Finite Difference Method or employing time-dependent fundamental solutions. For the latter case, specific numerical procedures for the solution of the time-dependent boundary integral equation equivalent to the diffusion equation are developed and different time-marching schemes tested. Finally, a BEM formulation for the solution of incompressible viscous flow problems governed by the Navier-Stokes equations together with the continuity equation is derived, following Lighthill's vorticity-velocity approach. Numerical procedures for the solution of the resulting set of non-linear integral equations are discussed in detail. Computer programs incorporating several of these features were developed, and examples of applications of such programs are presented throughout this work.</p

Spurred emulation: The EU and regional integration in SADC and Mercosur

This article analyses the EU's influence on regional institutional change in Mercosur and the Southern African Development Community from a diffusion perspective. Focusing on market-building objectives and dispute settlement mechanisms, it addresses the puzzle that policy-makers in both regions have, over time, increasingly adopted EU-style institutional arrangements even though alternative institutional models more suitable to their preferences for ‘pragmatic’, sovereignty-preserving cooperation have been available at various critical junctures of institutional evolution. The article makes two main arguments. First, it suggests that EU influence has affected outcomes in several specific ways that are irreducible to, and quite different from, mainstream functional accounts of economic regionalism. Second, it contends that the diffusion of EU institutional templates can be understood as a process of spurred emulation, when regional policy-makers emulate EU institutional models under conditions of uncertainty and promoted by EU-oriented domestic actors as well as the EU's direct involvement in the process