Bulk-plasmon polaritons in metamaterial-metamaterial one-dimensional photonic superlattices

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)We perform a theoretical study of the bulk-plasmon polaritons in one-dimensional photonic superlattices made up of alternate layers of different metamaterials with dispersive dielectric permittivities and magnetic permeabilities for both normal and oblique incidence. We demonstrate that for oblique incidence a finite projection along the growth direction of the electric or magnetic field of the incident wave associated with the transverse-magnetic or transverse-electric modes, respectively, leads to a coupling in each layer of the heterostructure of the photon modes with the bulk electric or magnetic metamaterial plasmons, respectively. Such photon-plasmon coupling gives rise to electric or magnetic longitudinal bulk-plasmon polariton bands in the photonic band structure of the metamaterial-metamaterial superlattice. We also analyze the conditions for suppression of the longitudinal bulk-plasmon polaritons in the photonic band structure and reflection spectra of such metamaterial-metamaterial heterostructures. (C) 2012 Elsevier Ltd. All rights reserved.5496106Colombian Agency CODI - Univ. of AntioquiaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FUJBFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Dehydrocrotonin and its beta-cyclodextrin complex: Cytotoxicity in V79 fibroblasts and rat cultured hepatocytes

Trans-dehydrocrotonin has antiulcerogenic and antitumor activities. A complex of beta-cyclodextrin with dehydrocrotonin was developed to improve the delivery of dehydrocrotonin. Complex in solid state was evaluated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). X-ray diffraction and scanning electron microscopy studies showed that dehydrocrotonin exists in a semicrystalline state in the complexed form with beta-cyclodextrin. Differential scanning calorimetry studies showed the existence of a complex of dehydrocrotonin with beta-cyclodextrin. The thermal gravimetric analysis studies confirmed the differential scanning calorimetry results of the complex. Free dehydrocrotonin and the dehydrocrotonin/ beta-cyclodextrin inclusion complex were assayed in freshly isolated rat hepatocytes and in V79 cells. Cytotoxicity was determined using nucleic acid content, methylthiazoletetrazolium (MTT) reduction and neutral red uptake assays. In all assays, there was a large reduction (3.5-16.1-fold) in the cytotoxicity of dehydrocrotonin in hepatocytes when complexed with p-cyclodextrin, whereas for V79 cells the decrease in cytotoxicity was 1.7- and 1.87-fold for MTT reduction and nucleic acid content assays, respectively. The lower cytotoxicity of the dehydrocrotonin/beta cyclodextrin complex compared to free dehydrocrotonin in rat hepatocytes and V79 cells suggests that such a complex may be useful for the administration of dehydrocrotonin in vivo. (c) 2005 Elsevier B.V. All rights reserved.51041671172

Absorption effects on plasmon polaritons in quasiperiodic photonic superlattices containing a metamaterial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Absorption effects on plasmon-polariton excitations in quasiperiodic (Fibonacci and Thue-Morse) one-dimensional stacks composed of layers of right-and left-handed materials are theoretically investigated. A Drude-type dispersive response for both the dielectric permittivity and magnetic permeability of the left-handed layer is considered. Maxwell's equations are solved for oblique incidence by using the transfer matrix formalism, and the reflection coefficient as a function of the frequency and incidence angle is obtained. The Fibonacci (or Thue-Morse) quasiperiodic structure leads to a Cantor-like photonic spectra for the plasmon-polariton modes. Moreover, results for the photonic band structure, density of states and reflection coefficient indicate that plasmon-polariton modes are robust in the presence of low and moderate levels of absorption.2238Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)FUJBColombian agency COLCIENCIASCODI-Univ. of AntioquiaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP