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1.
Sci Rep ; 13(1): 8196, 2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37210400

RESUMO

Designing a broadband, wide-angle, and high-efficient polarization converter with a simple geometry remains challenging. This work proposes a simple and computationally inexpensive method for devising broadband polarization conversion metasurfaces. We focus on a cross-shape configuration consisting of two bars of different lengths connected at the center. To design the metasurface, we decompose the system into two parts with two orthogonally polarized responses and calculate the response of each part separately. By selecting the parameters with a proper phase difference in the response between the two parts, we can determine the dimensions of the system. For designing broadband polarization conversion metasurfaces, we define a fitness function to optimize the bandwidth of the linear polarization conversion. Numerical results demonstrate that the proposed method can be used to design a metasurface that achieves a relative bandwidth of [Formula: see text] for converting linearly polarized waves into cross-polarized waves. Additionally, the average polarization conversion ratio of the designed metasurface is greater than [Formula: see text] over the frequency range of 10.9-28.5 GHz. This method significantly reduces the computational expense compared to the traditional method and can be easily extended to other complex structures and configurations.

2.
Eur J Pharmacol ; 858: 172467, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31216443

RESUMO

The present study investigates the cardioprotective effect of ß-caryophyllene against doxorubicin-induced acute cardiotoxicity in rats. Doxorubicin (12.5 mg/kg) and ß-caryophyllene (25, 50 or 100 mg/kg) were administered intraperitoneally to male albino Wistar rats. Doxorubicin-treated rats showed elevated levels of creatine kinase-MB in serum and oxidative stress in the myocardium as evidenced by decreased superoxide dismutase, catalase and glutathione with a concomitant rise in malondialdehyde levels. Doxorubicin also induced pro-inflammatory cytokines release following activation of the nuclear factor kappa-B and elevated expressions of inducible nitric oxide synthase and cyclooxygenase-2 in the myocardium. Additionally, doxorubicin also increased expression of γ-H2AX, a marker of DNA damage as well as increased expression of proapoptotic (Bax, p53, and active caspase-3) proteins along with the decreased expression of anti-apoptotic protein, Bcl2 in the myocardium. The histological and ultrastructural studies further revealed edema, inflammation and structural degeneration of cardiomyocytes following doxorubicin injection. However, treatment with ß-caryophyllene showed significant cardioprotective effects as evidenced by favorable improvement of biochemical and molecular parameters along with remarkable preservation of cardiomyocytes in histological and ultrastructural studies. Results of the present study demonstrate that ß-caryophyllene has potential to protect heart against doxorubicin-induced acute cardiotoxicity in rats. Moreover, the antioxidant and free radical scavenging properties of ß-caryophyllene was confirmed by in vitro assays. Provided the anticancer and chemosensitizing properties of ß-caryophyllene, the cardioprotective effects of ß-caryophyllene are suggestive of its multiple properties that provides an additional basis of its possible therapeutic application in chemotherapy-associated cardiotoxicity.


Assuntos
Apoptose/efeitos dos fármacos , Dieta , Doxorrubicina/toxicidade , Miocárdio/citologia , Miocárdio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Sesquiterpenos Policíclicos/farmacologia , Animais , Antioxidantes/metabolismo , Peso Corporal/efeitos dos fármacos , Citocinas/metabolismo , Citoproteção/efeitos dos fármacos , Dano ao DNA , Relação Dose-Resposta a Droga , Radical Hidroxila/metabolismo , Inflamação/tratamento farmacológico , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Miocárdio/patologia , NF-kappa B/metabolismo , Sesquiterpenos Policíclicos/uso terapêutico , Ratos , Ratos Wistar , Superóxidos/metabolismo
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