Allelic variants of IL1R1 gene associate with severe hand osteoarthritis

BACKGROUND: In search for genes predisposing to osteoarthritis (OA), several genome wide scans have provided evidence for linkage on 2q. In this study we targeted a 470 kb region on 2q11.2 presenting the locus with most evidence for linkage to severe OA of distal interphalangeal joints (DIP) in our genome wide scan families. METHODS: We genotyped 32 single nucleotide polymorphisms (SNPs) in this 470 kb region comprising six genes belonging to the interleukin 1 superfamily and monitored for association with individual SNPs and SNP haplotypes among severe familial hand OA cases (material extended from our previous linkage study; n = 134), unrelated end-stage bilateral primary knee OA cases (n = 113), and population based controls (n = 436). RESULTS: Four SNPs in the IL1R1 gene, mapping to a 125 kb LD block, provided evidence for association with hand OA in family-based and case-control analysis, the strongest association being with SNP rs2287047 (p-value = 0.0009). CONCLUSIONS: This study demonstrates an association between severe hand OA and IL1R1 gene. This gene represents a highly relevant biological candidate since it encodes protein that is a known modulator of inflammatory processes associated with joint destruction and resides within a locus providing consistent evidence for linkage to hand OA. As the observed association did not fully explain the linkage obtained in the previous study, it is plausible that also other variants in this genome region predispose to hand OA.Peer reviewe

Static and dynamic analysis of space frames using simple Timoshenko type elements

In this paper a finite element method for geometrically and materially non-linear analyses of space frames is described. Beams with both solid and thin-walled open cross-sections are considered. The equations of equilibrium are formulated using an updated incremental Lagrangian description. The elements developed can undergo large displacements and rotations, but the incremental rotations are assumed to be small. The material behaviour is described by elastoplastic, temperature-dependent elastoplastic and viscoplastic models with special reference to metals. Computationally, more economical formulations based on the relationship between stress resultants and generalized strain quantities are also presented. In the case of thin-walled beams the torsional behaviour is modelled using a two-parameter warping model, where the angle of twist and the axial variation of warping have independent approximations. This approach yields average warping shear strains directly from the displacement assumptions and no discrepancy between stress and strain fields exists

Modeling a Fe-Ga energy harvester fitted with magnetic closure using 3D magneto-mechanical finite element model

This paper presents the implementation of magneto-mechanical constitutive law utilizing thermodynamic approach in a 3D finite element solver using COMSOL Multiphysics software. The analytical expression for the magnetic field strength and stress is derived from the constitutive model utilizing magnetic flux density and mechanical strain as state variables. The constitutive model is successfully implemented in commercially available software COMSOL. This implementation allows 3D analysis of an energy harvester device efficiently and accurately. A prototype concept device is developed to validate the model and its implementation. The device is tested under uniaxial compressive loading by varying the preload, dynamic load and magnetic bias. The model is validated by comparing the simulated and experimental results. The comparison shows that the model can reasonably predict the optimal value of the preload and magnetic bias yielding maximum power and is able to follow the measurement trends. This model can be used as a suitable tool to analyze the behavior of the concept energy harvesters and determine the optimal design parameters.Peer reviewe

Modeling a Fe-Ga energy harvester fitted with magnetic closure using 3D magneto-mechanical finite element model

This paper presents the implementation of magneto-mechanical constitutive law utilizing thermodynamic approach in a 3D finite element solver using COMSOL Multiphysics software. The analytical expression for the magnetic field strength and stress is derived from the constitutive model utilizing magnetic flux density and mechanical strain as state variables. The constitutive model is successfully implemented in commercially available software COMSOL. This implementation allows 3D analysis of an energy harvester device efficiently and accurately. A prototype concept device is developed to validate the model and its implementation. The device is tested under uniaxial compressive loading by varying the preload, dynamic load and magnetic bias. The model is validated by comparing the simulated and experimental results. The comparison shows that the model can reasonably predict the optimal value of the preload and magnetic bias yielding maximum power and is able to follow the measurement trends. This model can be used as a suitable tool to analyze the behavior of the concept energy harvesters and determine the optimal design parameters