977 resultados para 63, 22 p.


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Juvenile idiopathic arthritis (JIA) is a heterogeneous group of childhood chronic arthritides, associated with chronic uveitis in 20% of cases. For JIA patients responding inadequately to conventional disease-modifying anti-rheumatic drugs (DMARDs), biologic therapies, anti-tumor necrosis factor (anti-TNF) agents are available. In this retrospective multicenter study, 258 JIA-patients refractory to DMARDs and receiving biologic agents during 1999-2007 were included. Prior to initiation of anti-TNFs, growth velocity of 71 patients was delayed in 75% and normal in 25%. Those with delayed growth demonstrated a significant increase in growth velocity after initiation of anti-TNFs. Increase in growth rate was unrelated to pubertal growth spurt. No change was observed in skeletal maturation before and after anti-TNFs. The strongest predictor of change in growth velocity was growth rate prior to anti-TNFs. Change in inflammatory activity remained a significant predictor even after decrease in glucocorticoids was taken into account. In JIA-associated uveitis, impact of two first-line biologic agents, etanercept and infliximab, and second-line or third-line anti-TNF agent, adalimumab, was evaluated. In 108 refractory JIA patients receiving etanercept or infliximab, uveitis occurred in 45 (42%). Uveitis improved in 14 (31%), no change was observed in 14 (31%), and in 17 (38%) uveitis worsened. Uveitis improved more frequently (p=0.047) and frequency of annual uveitis flares was lower (p=0.015) in those on infliximab than in those on etanercept. In 20 patients taking adalimumab, 19 (95%) had previously failed etanercept and/or infliximab. In 7 patients (35%) uveitis improved, in one (5%) worsened, and in 12 (60%) no change occurred. Those with improved uveitis were younger and had shorter disease duration. Serious adverse events (AEs) or side-effects were not observed. Adalimumab was effective also in arthritis. Long-term drug survival (i.e. continuation rate on drug) with etanercept (n=105) vs. infliximab (n=104) was at 24 months 68% vs. 68%, and at 48 months 61% vs. 48% (p=0.194 in log-rank analysis). First-line anti-TNF agent was discontinued either due to inefficacy (etanercept 28% vs. infliximab 20%, p=0.445), AEs (7% vs. 22%, p=0.002), or inactive disease (10% vs. 16%, p=0.068). Females, patients with systemic JIA (sJIA), and those taking infliximab as the first therapy were at higher risk for treatment discontinuation. One-third switched to the second anti-TNF agent, which was discontinued less often than the first. In conclusion, in refractory JIA anti-TNFs induced enhanced growth velocity. Four-year treatment survival was comparable between etanercept and infliximab, and switching from first-line to second-line agent a reasonable therapeutic option. During anti-TNF treatment, one-third with JIA-associated anterior uveitis improved.

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Overexpression of the epidermal growth factor receptor family genes, which include ErbB-1, 2, 3 and 4, has been implicated in a number of cancers. We have studied the extent of ErbB-2 overexpression among Indian women with sporadic breast cancer. Methods: Immmunohistochemistry and genomic polymerase chain reaction (PCR) were used to study the ErbB2 overexpression. ErbB2 status was correlated with other clinico-pathological parameters, including patient survival. Results: ErbB-2 overexpression was detected in 43.2% (159/368) of the cases by immunohistochemistry. For a sub-set of patients (n = 55) for whom total DNA was available, ErbB-2 gene amplification was detected in 25.5% (14/55) of the cases by genomic PCR. While the ErbB2 overexpression was significantly higher in patients with lymphnode (2 = 12.06, P 0.001), larger tumor size (2 = 8.22, P = 0.042) and ductal carcinoma (2 = 15.42, P 0.001), it was lower in patients with disease-free survival (2 = 22.13, P 0.001). Survival analysis on a sub-set of patients for whom survival data were available (n = 179) revealed that ErbB-2 status (2 =25.94, P 0.001), lymphnode status (2 = 12.68, P 0.001), distant metastasis (2 = 19.49, P 0.001) and stage of the disease (2 = 28.04, P 0.001) were markers of poor prognosis. Conclusions: ErbB-2 overexpression was significantly greater compared with the Western literature, but comparable to other Indian studies. Significant correlation was found between ErbB-2 status and lymphnode status, tumor size and ductal carcinoma. ErbB-2 status, lymph node status, distant metastasis and stage of the disease were found to be prognostic indicators.

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We report results from a first principles calculation of spatially dependent correlation functions around a magnetic impurity in metals described by the nondegenerate Anderson model. Our computations are based on a combination of perturbative scaling theory and numerical renormalization group methods. Results for the conduction election charge density around the impurity and correlation functions involving the conduction electron and impurity charge and spin densities will be presented. The behavior in various regimes including the mixed valent regime will be explored.

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Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin Bi films in a magnetic field are reported. These I-V's show hysteresis for all films, grown both with and without thin Ge underlayers. Films on Ge underlayers, close to superconductor-insulator transition, show a peak in the critical current, indicating a structural transformation of the vortex solid. These underlayers, used to make the films more homogeneous, are found to be more effective in pinning the vortices. The upper critical fields (B-c2) of these films are determined from the resistive transitions in perpendicular magnetic field. The temperature dependence of the upper critical field is found to differ significantly from Ginzburg-Landau theory, after modifications for disorder.

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[1] D. Tse and P. Viswanath, Fundamentals of Wireless Communication.Cambridge University Press, 2006. [2] H. Bolcskei, D. Gesbert, C. B. Papadias, and A.-J. van der Veen, Spacetime Wireless Systems: From Array Processing to MIMO Communications.Cambridge University Press, 2006. [3] Q. H. Spencer, C. B. Peel, A. L. Swindlehurst, and M. Haardt, An introduction to the multiuser MIMO downlink, IEEE Commun. Mag.,vol. 42, pp. 6067, Oct. 2004. [4] K. Kusume, M. Joham,W. Utschick, and G. Bauch, Efficient tomlinsonharashima precoding for spatial multiplexing on flat MIMO channel,in Proc. IEEE ICC2005, May 2005, pp. 20212025. [5] R. Fischer, C. Windpassinger, A. Lampe, and J. Huber, MIMO precoding for decentralized receivers, in Proc. IEEE ISIT2002, 2002, p.496. [6] M. Schubert and H. Boche, Iterative multiuser uplink and downlink beamforming under SINR constraints, IEEE Trans. Signal Process.,vol. 53, pp. 23242334, Jul. 2005. [7] , Solution of multiuser downlink beamforming problem with individual SINR constraints, IEEE Trans. Veh. Technol., vol. 53, pp.1828, Jan. 2004. [8] A. Wiesel, Y. C. Eldar, and Shamai, Linear precoder via conic optimization for fixed MIMO receivers, IEEE Trans. Signal Process., vol. 52,pp. 161176, Jan. 2006. [9] N. Jindal, MIMO broadcast channels with finite rate feed-back, in Proc. IEEE GLOBECOM2005, Nov. 2005. [10] R. Hunger, F. Dietrich, M. Joham, and W. Utschick, Robust transmit zero-forcing filters, in Proc. ITG Workshop on Smart Antennas, Munich,Mar. 2004, pp. 130137. [11] M. B. Shenouda and T. N. Davidson, Linear matrix inequality formulations of robust QoS precoding for broadcast channels, in Proc.CCECE2007, Apr. 2007, pp. 324328. [12] M. Payaro, A. Pascual-Iserte, and M. A. Lagunas, Robust power allocation designs for multiuser and multiantenna downlink communication systems through convex optimization, IEEE J. Sel. Areas Commun.,vol. 25, pp. 13921401, Sep. 2007. [13] M. Biguesh, S. Shahbazpanahi, and A. B. Gershman, Robust downlink power control in wireless cellular systems, EURASIP Jl. Wireless Commun. Networking, vol. 2, pp. 261272, 2004. [14] B. Bandemer, M. Haardt, and S. Visuri, Liner MMSE multi-user MIMO downlink precoding for users with multple antennas, in Proc.PIMRC06, Sep. 2006, pp. 15. [15] J. Zhang, Y. Wu, S. Zhou, and J. Wang, Joint linear transmitter and receiver design for the downlink of multiuser MIMO systems, IEEE Commun. Lett., vol. 9, pp. 991993, Nov. 2005. [16] S. Shi, M. Schubert, and H. Boche, Downlink MMSE transceiver optimization for multiuser MIMO systems: Duality and sum-mse minimization,IEEE Trans. Signal Process., vol. 55, pp. 54365446, Nov.2007. [17] A. Mezghani, M. Joham, R. Hunger, and W. Utschick, Transceiver design for multi-user MIMO systems, in Proc. WSA 2006, Mar. 2006. [18] R. Doostnejad, T. J. Lim, and E. Sousa, Joint precoding and beamforming design for the downlink in a multiuser MIMO system, in Proc.WiMob2005, Aug. 2005, pp. 153159. [19] N. Vucic, H. Boche, and S. Shi, Robust transceiver optimization in downlink multiuser MIMO systems with channel uncertainty, in Proc.IEEE ICC2008, Beijing, China, May 2008. [20] A. Ben-Tal and A. Nemirovsky, Selected topics in robust optimization,Math. Program., vol. 112, pp. 125158, Feb. 2007. [21] D. Bertsimas and M. Sim, Tractable approximations to robust conic optimization problems, Math. Program., vol. 107, pp. 536, Jun. 2006. [22] P. Ubaidulla and A. Chockalingam, Robust Transceiver Design for Multiuser MIMO Downlink, in Proc. IEEE Globecom2008, New Orleans, USA, Dec. 2008, to appear. [23] S. Boyd and L. Vandenberghe, Convex Optimization. Cambridge University Press, 2004. [24] G. H. Golub and C. F. V. Loan, Matrix Computations. The John Hopkins University Press, 1996.

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O artigo aborda a problemtica da gesto de obras pblicas no Brasil, alvo de recorrentes irregularidades apontadas pelos rgos de controle e pela imprensa nacional. A pesquisa parte do diagnstico constante do Relatrio "O Retrato do Desperdcio no Brasil", apresentado em novembro de 1995 pela Comisso Temporria do Senado Federal destinada a inventariar as obras inacabadas custeadas com recursos federais, e busca cotejar os problemas apontados naquele Relatrio com as medidas adotadas pelo Governo Federal e pelo Congresso Nacional para aperfeioar a gesto de obras pblicas. O autor argumenta que as medidas adotadas, conquanto corretas, receberam prioridade, intensidade e abrangncia incompatveis com a magnitude do problema.