60 research outputs found

    EORTC (30885) randomised phase III study with recombinant interferon alpha and recombinant interferon alpha and gamma in patients with advanced renal cell carcinoma. The EORTC Genitourinary Group.

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    In the treatment of renal cell carcinoma both complete (CRs) and partial remissions (PRs) have been obtained using recombinant (r) interferon alpha (IFN-alpha), with response rates ranging from 0 to 31% (mean 16%). rIFN-gamma is a potent immunostimulating agent, but the clinical experience of its use is limited and results are conflicting. In a phase II study with the combination of rIFN-alpha 2c (Boehringer Ingelheim) and rIFN-gamma (Genentech, supplied by Boehringer Ingelheim) in 31 eligible patients, a response rate of 25% was recorded. Based on this observation a randomised phase III study was initiated to investigate the possible advantage of the addition rIFN-gamma to rIFN-alpha 2c treatment. Treatment consisted of rIFN-alpha 2c 30 micrograms m-2 = 10 x 10(6) IU m-2 s.c. twice weekly in arm A and the same dose of rIFN-alpha combined with rIFN-gamma 100 micrograms m-2 = 2 x 10(6) IU m-2 in arm B. Eligibility criteria included documented progression of disease; patients with bone lesions only and overt central nervous system metastases were excluded. Between November 1988 and September 1990, 102 patients were entered into the study. An interim analysis showed a response in 7/53 (13%) patients (two CRs and five PRs) in the rIFN-alpha 2c monotherapy arm and in 2/45 (4%) (one CR and one PR) patients in the combination arm. This difference was not statistically significant (P = 0.17). The probability of missing an eventual 10% advantage for the combination is 0.001. The numbers are insufficient to rule out a negative effect of the addition of rIFN-gamma. The dose intensity of IFN-alpha 2c for the two treatment arms was the same. The addition of rIFN-gamma does not improve the response rate of rIFN-alpha 2c monotherapy. A possible detrimental effect cannot be excluded

    Effect of FEM choices in the modelling of incremental forming of aluminium sheets

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    peer reviewedThis paper investigates the process of single point incremental forming of an aluminium cone with a 50-degree wall angle. Finite element (FE) models are established to simulate the process. Different FE packages have been used. Various aspects associated with the numerical choices as well as the material and process parameters have been studied. The final geometry and the reaction forces are presented as the results of the simulations. Comparison between the simulation results and the experimental data is also made

    Forming limit predictions for single-point incremental sheet metal forming

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    peer reviewedA characteristic of incremental sheet metal forming is that much higher deformations can be achieved than conventional forming limits. In this paper it is investigated to which extent the highly non-monotonic strain paths during such a process may be responsible for this high formability. A Marciniak-Kuczynski (MK) model is used to predict the onset of necking of a sheet subjected to the strain paths obtained by finite-element simulations. The predicted forming limits are considerably higher than for monotonic loading, but still lower than the experimental ones. This discrepancy is attributed to the strain gradient over the sheet thickness, which is not taken into account in the currently used MK model

    ICESTARS : integrated circuit/EM simulation and design technologies for advanced radio systems-on-chip

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    ICESTARS solved a series of critical issues in the currently available infrastructure for the design and simulation of new and highly-complex Radio Frequency (RF) front ends operating beyond 10 and up to 100 GHz. Future RF designs demand an increasing blend of analog and digital functionalities. The super and extremely high frequency (SHF, 3-30GHz, and EHF, 30-300GHz) ranges will be used to accomplish future demands for higher capacity channels. With todays frequency bands of approximately 1 to 3 GHz it is impossible to realize extremely high data transfer rates. Only a new generation of CAD and EDA tools will ensure the realization of complex nanoscale designs. It necessitates both new modeling approaches and new mathematical solution procedures for differential equations with largely differing time scales, analysis of coupled systems of DAEs (circuit equations) and PDEs (Maxwell equations for electromagnetic couplings) plus numerical simulations with mixed analog and digital signals. In ICESTARS new techniques and mathematical models working in highly integrated environments were developed to resolve this dilemma. The ICESTARS research area covered the three domains of RF design: (1) time-domain techniques, (2) frequency-domain techniques, and (3) EM analysis and coupled EM circuit analysis. The ICESTARS consortium comprised two industrial partners (NXP Semiconductors, Infineon Technologies AG), two SMEs (Magwel, AWR-APLAC) and five universities (Upper Austria, Cologne, Oulu, Wuppertal, Aalto), involving mathematicians, electronic engineers, and software engineers

    Development of a contact model adapted to incremental forming

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    peer reviewedThe objective of this article is to present the development of a new method for taking into account the contact between the tool and the blank during incremental forming. First, the need for such a model is justified. Then, the basic features of the adapted dynamic explicit scheme are presented, followed by the new algorithms proposed and their programming. Finally, some conclusions and perspectives are drawn

    Les prothèses de cheville: un défi prometteur

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    - Défiant l'arthrodèse sur son terrain historique de «gold standard», l'arthroplastie totale de la cheville s'impose progressivement comme une alternative viable au traitement chirurgical de la cheville dégénérative. - Les premières prothèses de cheville furent implantées en 1970 avec des résultats décevants. Au bénéfice de meilleures connaissances biomécaniques, les prothèses dites «de seconde génération» ont vu le jour au cours des années 1980 et apportent aujourd'hui des résultats prometteurs à moyen terme avec un taux de survie des implants de 90% à dix ans. - La cheville est l'articulation la plus souvent traumatisée du corps humain. Nantie d'une surface articulaire réduite, elle doit pourtant se soumettre à des forces allant jusqu'à sept fois le poids du corps. Ceci est un défi à la prothétique. - L'arthroplastie totale de la cheville s'adresse à l'arthrose de cheville, souvent post-traumatique, à la cheville rhumatoïde, ainsi qu'à d'autres arthropathies dégénératives. Le succès de l'intervention dépend d'une sélection soigneuse des patients contrairement à l'arthrodèse qui est applicable à la majorité des cas. - Pour consolider la place de la prothétique dans le traitement de la cheville dégénérative, des travaux de recherche fondamentale et clinique objectifs incluant l'amélioration des implants, l'étude de l'efficacité fonctionnelle des prothèses, de leur efficacité en terme de priorités du patient et de qualité de vie, et surtout l'évaluation de la survie des implants à long terme sont encore nécessaires

    Model identification and FE simulations: effect of different yield loci and hardening laws in sheet forming

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    peer reviewedThe bi-axial experimental equipment [1] developed by Flores enables to perform Baushinger shear tests and successive or simultaneous simple shear tests and plane-strain tests. Such experiments and classical tensile tests investigate the material behavior in order to identify the yield locus and the hardening models. With tests performed on two steel grades, the methods applied to identify classical yield surfaces such as Hill or Hosford ones as well as isotropic Swift type hardening or kinematic Armstrong–Frederick hardening models are explained. Comparison with the Taylor-Bishop-Hill yield locus is also provided. The effect of both yield locus and hardening model choice will be presented for two applications: Single Point Incremental Forming (SPIF) and a cup deep drawing

    Comparison of the tests chosen for material parameter identification to predict single point incremental forming forces

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    peer reviewedSingle Point Incremental Forming is a sheet forming process that uses a smooth-ended tool following a specific tool path and thus eliminates the need for dedicated die sets. Using this method, the material can reach a very high deformation level. A wide variety of shapes can be obtained without specific and costly equipment. To be able to optimize the process, a model and its material parameters are required. The inverse method has been used to provide material data by modeling experiments directly performed on a SPIF set-up and comparing them to the experimental measurements. The tests chosen for this study can generate heterogeneous stress and strain fields. They are performed with the production machine itself and are appropriate for the inverse method since their simulation times are not too high
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