Enhancement of near-cloaking. Part II: the Helmholtz equation

The aim of this paper is to extend the method of improving cloaking structures in the conductivity to scattering problems. We construct very effective near-cloaking structures for the scattering problem at a fixed frequency. These new structures are, before using the transformation optics, layered structures and are designed so that their first scattering coefficients vanish. Inside the cloaking region, any target has near-zero scattering cross section for a band of frequencies. We analytically show that our new construction significantly enhances the cloaking effect for the Helmholtz equation.Comment: 16pages, 12 fugure

Genetic variants related to nicotine dependence

Large-scale population studies have proved that genetic factors contribute to individual differences in smoking behavior. Genes responsible for nicotine's pharmacokinetics and pharmacodynamics seem mainly involved, although a significant fraction of variance remains unexplained. In this study we examined 10 SNPs from 8 candidate genes with positive previous reports of association with smoking. A total of 454 Italian unrelated subjects were genotyped by a multiplex minisequencing assay through the SNaPShot kit. Cases were chosen as current and former nicotine dependent (FTND. >. 4 and SQ. >. 15), while controls were smoking-exposed but non-dependent and never smoker individuals (FTND = 0 and SQ < 10 and FTND = 0 and SQ = 0, respectively). Preliminary results shows that the SNPs CHRNA5-rs16969968 and CHRNA3-rs1051730 could be associated with risk of developing nicotine dependence. Factors as age, sex, and exposition to smoke were also found as possible factors of risk of nicotine addiction. The identification of susceptibility loci for individual response to substance abuse is particularly motivating for medicine for the global epidemic dimension of addictions and the urgent need of effective preventive and therapeutic strategies. 2011 Elsevier Ireland Ltd