In this paper, a simple conformal load-bearing antenna structure smart skin with a multi-layer sandwich structure composed of carbon/epoxy, glass/epoxy, and a dielectric polymer was designed and fabricated. The mechanical properties of each material in the designed smart skin were obtained from experiments. Tests and analyses were conducted to study the behavior of the smart skin under compressive loads. The designed smart skin failed due to buckling before compression failure. The stresses of each layer and the first failed layer of the smart skin were predicted using MSC/NASTRAN. The finite element model was verified by comparing the numerical results from geometrical linear/nonlinear analyses with the measured data. The numerically predicted structural behavior of the smart skin agreed well with the experimental data. The results showed that the carbon/epoxy layer took charge of most of the compressive load, and the first failure occurred in the dielectric layer while the other layers remained safe. A numerical model was used to obtain design data from the parametric study. The effect of changing the design variables on the buckling and compressive behavior of the smart skin was also investigated. As a result, it was confirmed that the transverse shear moduli of the honeycomb core had a serious impact on the buckling load of the smart skin when the shear deformation was considerable.

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ObjectivesSeveral lines of evidence suggest that brain-derived neurotrophic factor (BDNF) is involved in the pathophysiology of fibromyalgia (FM) and studies have found that FM patients have altered serum and plasma BDNF levels. However, it is not known whether polymorphisms of the BDNF gene are associated with FM. In this study, we explored the association between polymorphisms of the BDNF gene with FM susceptibility and the severity of symptoms.MethodsThe study enrolled 409 patients with FM and 423 controls from 10 medical centres that participated in the Korean nationwide FM survey study. Alleles at 10 positions in the BDNF gene were genotyped: rs2883187 (C>T), rs7103873 (G>C), rs7103411(C>T), rs10835210 (C>A), rs11030104 (A>G), rs12273539 (C>T), rs11030102(C>G), rs11030101 (A>T), rs6265 (G>A), and rs7124442(C>T).ResultsThe allele and genotype frequencies of BDNF rs11030104 differed significantly between the FM patients and controls (p=0.031). The GG genotype of rs11030104 had a protective role against FM (p=0.016) and the G allele of rs11030104 was negatively associated with the presence of FM compared with the A allele (p=0.013). In comparison, although the allele and genotype frequencies of BDNF rs12273539 did not differ between the FM patients and controls, the TT genotype of BDNF rs12273539 was associated with susceptibility to FM (p=0.038). Haplotype analyses suggested that some BDNF haplotypes have a protective role against FM. Finally, we found that that some genotypes and haplotypes of the BDNF gene contribute to the specific symptoms of FM.ConclusionsThis study is the first to evaluate the associations of BDNF gene polymorphisms with FM. Our results suggest that some BDNF single-nucleotide polymorphisms and haplotypes are associated with susceptibility to, and contribute to the symptoms of, FM.Disclosure of InterestNone declared