Aplicação do método LTT às estruturas retangulares e triangulares em multicamadas e empilhadas em substratos PBG para comunicações móveis

Recently the planar antennas have been studied due to their characteristics as well as the advantages that they offers when compared with another types of antennas. In the mobile communications area, the need for this kind of antennas have became each time bigger due to the intense increase of the mobile communications that needs of antennas which operate in multifrequency and wide bandwidth. The microstrip antennas presents narrow bandwidth due the loss in the dielectric generated by radiation. Another limitation is the radiation pattern degradation due the generation of surface waves in the substrate. In this work some used techniques to minimize the disadvantages (previously mentioned) of the use of microstrip antennas are presented, those are: substrates with PBG material - Photonic Bandgap, multilayer antennas and with stacked patches. The developed analysis in this work used the TTL - Transverse Transmission Line method in the domain of Fourier transform, that uses a component of propagation in the y direction (transverse to the direction real of propagation z), treating the general equations of electric and magnetic field as functions of y and y . This work has as objective the application of the TTL method to microstrip structures with single and multilayers of rectangular and triangular patches, to obtaining the resonance frequency and radiation pattern of each structure. This method is applied for the treatment of the fields in stacked structures. The Homogenization theory will be applied to obtaining the effective permittivity for s and p polarizations of the substrate composed of PBG material. Numerical results for the triangular and rectangular antennas with single layer, multilayers resonators with triangular and rectangular patches are presented (in photonic and isotropic substrates). Conclusions and suggestions for continuity of this work are presented

Enhancement of Drug-Specific Lymphocyte Proliferation Using CD25-Depleted CD3(+) Effector Cells

Background: The lymphocyte transformation test (LTT) is used for in vitro diagnosis of drug hypersensitivity reactions. While its specificity is over 90%, sensitivity is limited and depends on the type of reaction, drug and possibly time interval between the event and analysis. Removal of regulatory T cells (Treg/CD25(hi)) from in vitro stimulated cell cultures was previously reported to be a promising method to increase the sensitivity of proliferation tests. Objective: The aim of this investigation is to evaluate the effect of removal of regulatory T cells on the sensitivity of the LTT. Methods: Patients with well-documented drug hypersensitivity were recruited. Peripheral blood mononuclear cells, isolated CD3(+) and CD3(+) T cells depleted of the CD25(hi) fraction were used as effector cells in the LTT. Irrelevant drugs were also included to determine specificity. (3)H-thymidine incorporation was utilized as the detection system and results were expressed as a stimulation index (SI). Results: SIs of 7/11 LTTs were reduced after a mean time interval of 10.5 months (LTT 1 vs. LTT 2). Removal of the CD25(hi) fraction, which was FOXP3(+) and had a suppressive effect on drug-induced proliferation, resulted in an increased response to the relevant drugs. Sensitivity was increased from 25 to 82.35% with dramatically enhanced SI (2.05 to 6.02). Specificity was not affected. Conclusion: Removal of Treg/CD25(hi) cells can increase the frequency and strengths of drug-specific proliferation without affecting specificity. This approach might be useful in certain drug hypersensitivity reactions with borderline responses or long time interval since the hypersensitivity reaction. © 2014 S. Karger AG, Basel.