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1. RKIP inhibition in cervical cancer is associated with higher tumor aggressive behavior and resistance to cisplatin therapy.

Author

Olga Martinho, Filipe Pinto, Sara Granja, Vera Miranda-Gonçalves, Marise A R Moreira, Luis F J Ribeiro, Celso di Loreto, Marsha R Rosner, Adhemar Longatto-Filho, and Rui Manuel Reis

Subjects
Medicine, Science
Abstract

Cervical cancer is one of the most common cancers in women worldwide, being high-risk group the HPV infected, the leading etiological factor. The raf kinase inhibitory protein (RKIP) has been associated with tumor progression and metastasis in several human neoplasms, however its role on cervical cancer is unclear. In the present study, 259 uterine cervix tissues, including cervicitis, cervical intraepithelial lesions and carcinomas, were analyzed for RKIP expression by immunohistochemistry. We found that RKIP expression was significantly decreased during malignant progression, being highly expressed in non-neoplastic tissues (54% of the samples; 73/135), and expressed at low levels in the cervix invasive carcinomas (∼15% (19/124). Following in vitro downregulation of RKIP, we observed a viability and proliferative advantage of RKIP-inhibited cells over time, which was associated with an altered cell cycle distribution and higher colony number in a colony formation assay. An in vitro wound healing assay showed that RKIP abrogation is associated with increased migratory capability. RKIP downregulation was also associated with an increased vascularization of the tumors in vivo using a CAM assay. Furthermore, RKIP inhibition induced cervical cancer cells apoptotic resistance to cisplatin treatment. In conclusion, we described that RKIP protein is significantly depleted during the malignant progression of cervical tumors. Despite the lack of association with patient clinical outcome, we demonstrate, in vitro and in vivo, that loss of RKIP expression can be one of the factors that are behind the aggressiveness, malignant progression and chemotherapy resistance of cervical cancer.

Published
2013
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3. Electric-Field Effects on the Band-Edge States of GaAs/AlAs Coupled Quantum Wells

Author

Rodrigo B. Capaz, F. J. Ribeiro, and Belita Koiller

Subjects
Physics, Condensed matter physics, Chemistry, Quantum-confined Stark effect, General Physics and Astronomy, Heterojunction, Electronic structure, Electron, Gaas alas, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Tight binding, Atomic orbital, Electric field, Perpendicular, Electron configuration, Quantum well
Abstract

Optical experiments on electric field tunable AlAs/GaAs coupled quantum wells clearly demonstrate that the optical nature of these structures can be directly controlled by an applied electric field. In this work we are concerned with calculation and analysis of the first electron and holOe states in these structures. We take into account the effects of the heterostrucuture geometry and of the external uniform electric field applied perpendicularly to the layers, which may lead to an anticrossing of low-lying electron levels in the system. Calculations are performed within the tight-binding supercell formalism with interactions between atomic orbitals up to second nearest-neighbors. Our results show that for GaAs layers less than 30 Å wide, application of electric fields takes the structures from typeII to type I heteroestructure behavior. Our estimated value of the electric field intensity needed to cause this transition is in good agreement with the experimental results for comparable heteroestructures geometries .

Published
2002
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4. Coherent properties and rabi oscillations in two-level donor systems

Author

H. S. Brandi, F. J. Ribeiro, A. Bruno-Alfonso, Andrea Latge, L. E. Oliveira, Universidade Federal Fluminense (UFF), Univ Estadual Feira Santana, Universidade Estadual Paulista (Unesp), Universidade Estadual de Campinas (UNICAMP), and Universidade Federal do Rio de Janeiro (UFRJ)

Subjects
Physics, Coherence time, Rabi cycle, Condensed matter physics, Rabi oscillations, Condensed Matter::Other, Coherent properties, Dephasing, General Physics and Astronomy, Two-level donor systems, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter::Materials Science, Quantum dot, Electric dipole transition, Rabi problem, Excitation, Rabi frequency
Abstract

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2014-02-26T17:25:21Z No. of bitstreams: 1 WOS000238575800050.pdf: 160330 bytes, checksum: 10f14bebba39a540b2177930d32d5295 (MD5) Made available in DSpace on 2014-02-26T17:25:21Z (GMT). No. of bitstreams: 1 WOS000238575800050.pdf: 160330 bytes, checksum: 10f14bebba39a540b2177930d32d5295 (MD5) Previous issue date: 2006-06-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:26:30Z No. of bitstreams: 1 WOS000238575800050.pdf: 160330 bytes, checksum: 10f14bebba39a540b2177930d32d5295 (MD5) Made available in DSpace on 2014-05-20T13:26:30Z (GMT). No. of bitstreams: 1 WOS000238575800050.pdf: 160330 bytes, checksum: 10f14bebba39a540b2177930d32d5295 (MD5) Previous issue date: 2006-06-01 Coherent properties and Rabi oscillations in two-level donor systems, under terahertz excitation, are theoretically investigated. Here we are concerned with donor states in bulk GaAs and GaAs-(Ga,Al)As quantum dots. We study confinement effects, in the presence of an applied magnetic field, on the electronic and on-center donor states in GaAs- (Ga,Al)As dots, as compared to the situation in bulk GaAs, and estimate some of the associated decay rate parameters. Using the optical Bloch equations with damping, we study the time evolution of the Is and 2p(+) states in the presence of an applied magnetic field and of a terahertz laser. We also discuss the role played by the distinct dephasing rates on the photocurrent and calculate the electric dipole transition moment. Results indicate that the Rabi oscillations are more robust as the total dephasing rate diminishes, corresponding to a favorable coherence time. Univ Fed Fluminense, Dept Fis, BR-24210340 Niteroi, RJ, Brazil Univ Estadual Feira Santana, Dept Fis, BR-44031460 Feira de Santana, BA, Brazil Univ Estadual Paulista, Fac Ciências, Dept Matemat, BR-17033360 Bauru, SP, Brazil Univ Estadual Campinas, Inst Fis, BR-13083970 Campinas, SP, Brazil Univ Fed Rio de Janeiro, Inst Fis, BR-21945970 Rio de Janeiro, Brazil Univ Estadual Paulista, Fac Ciências, Dept Matemat, BR-17033360 Bauru, SP, Brazil

Published
2006

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