Chalcones and their derivatives exhibit numerous pharmacological activities such as antibacterial, antifungal, cytotoxic, antinociceptive and anti-inflammatory. Recently, they have been assessed aiming for novel application in nonlinear optics and in the treatment of immune diseases and cancers. In this study, we investigate the optical properties of synthetic chalcona 1E,4E-1-(4-chlorophenyl)-5-(2,6,6-trimethylcyclohexen-1-yl)penta-1,4-dien-3-one (CAB7β) and its antiangiogenic potential using the chorioallantoic membrane (CAM) with the S180 sarcoma cell line. Experimental and theoretical results show intense absorption in the UVA-UVC region, which is associated with a π → π* transition with intramolecular charge transfer from the trimethyl-cyclohexen-1-yl ring to the chlorophenyl ring. Quantum chemical calculations of the first hyperpolarizability, accounting for both solvent and frequency dispersion effects, are in very good concordance with hyper-Rayleigh scattering measurements. In addition, two-photon absorption allowed band centered at 650 nm was observed. Concerning antiangiogenic activity, CAB7β causes a significant reduction in the total number, junctions, length and caliber of blood vessels stimulated by S180 cells reducing the presence of blood vessels, inflammatory cells and others elements related to angiogenic process. It is found that CAB7β is a versatile compound and a promising candidate for linear and nonlinear optical applications, in therapy against sarcoma and phototherapy.
The quasi-two-dimensional electron cyclotron mass in GaN-AlxGa1,xN heterostructures is theoretically calculated. The shifting in Landau Levels due to the electron Longitudinal Optical phonon interaction is calculated through the Second Order Improved Wigner Brillouin Perturbation Theory IWBPT. Experimental results recently obtained for GaN heterojunction are well described by the theory. W e h a ve also investigated the e ects of the electronic density on the Cyclotron Resonance frequency.
I IntroductionCyclotron Resonance CR is a powerful experimental technique to investigate the e ective mass of quasitwo dimensional Q2D electron systems in semiconductor structures of reduced dimensionality. In the past, InSb inversion layer of the metal-oxide-semiconductor MOS and GaAs-AlGaAs heterostructures have been intensively studied by several authors 1 . In GaAsbased heterostructures the cyclotron resonance experiments have shown that the polaronic e ects are reduced in comparison with the results for the semiconductor bulk.More recently, the Cyclotron Resonance CR mass of quasi-two-dimensional electrons con ned in a GaN AlGaN heterojunction was experimentally investigated 2; 3 . Gallium Nitrite GaN and related III-V ternary alloys as Al x Ga 1,x N and Ga x In 1,x N are wide direct bandgap semiconductors, and the GaN is a moderately polar material with Fr ohlich coupling constant = 0 :49. Since the rst report by Dingle et al. 4 on GaN optical properties numerous investigations have been made, motivated by the potential technological applications of this material for construction of the optoelectronic devices. However, little is still known about the basic properties of these materials, and only in the recent y ears there appeared some theoretical and experimental investigations.In this paper we calculate the electron cyclotron mass in a GaN AlGaN heterojunction and in a GaN Quantum Well QW with in nite potential barrier for the electronic con nement. We take i n to account the electron-phonon-longitudinal optical LO interaction polaronic e ects through the Improved WignerBrillouin Perturbation Theory IWBPT. The IWBPT has been successfully applied to GaAs-AlGaAs heterostructures 5 , 7 . For the GaN heterojunction our theoretical results for CR frequency were compared with the experimental results presented in Ref. 2 . We also investigate the e ects of the electronic density o n the CR frequency.
II TheoryThe Hamiltonian describing one electron con ned in the GaN side, in the heterojunction or QW, in the presence of a magnetic eld applied perpendicular to interface and interacting with the bulk LO phonons, can be written as in the e ective mass approximation,
el for the magnetic field in the two considered configurations. Comparison of our results for the half-parabolic quantum wells with available experimental data is made.]]>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.