Yazar "Sahin, Ali" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Experiential Investigation of Nonlinear Acoustic Field Structure in Two and Three Dimensions
    (Ieee, 2016) Kaleci, Devkan; Sahin, Ali; Karabocu, Baki
    In this paper, two and three dimensional experimental nonlinear acoustic pressure fields that are produced by circular sources are presented. We developed an experiment systems to measure results of nonlinear acoustic pressure fields for the first three harmonic components along both acoustic and radial axis, in both two and three dimensions. The use of sub-harmonics to improve the lateral and axial image quality is also discussed. In addition, the experimental results are compared with theoretical results for the first three harmonics and are observed to essentially consistent with the theoretical results.
  • Küçük Resim Yok
    Öğe
    A national, multicenter, retrospective study evaluating retention rate and efficacy of tocilizumab treatment in patients with active rheumatoid arthritis who had an inadequate response to csDMARDs and/or TNF inhibitors
    (Tubitak Scientific & Technological Research Council Turkey, 2023) Inanc, Guezide Nevsun; Terzioglu, Mustafa Ender; Karabulut, Yusuf; Yilmaz, Zevcet; Tarhan, Emine Figen; Enecik, Mehmet Emin; Sahin, Ali
    Background/aim: To describe the disease activity and retention rate in rheumatoid arthritis (RA) patients with inadequate response (IR) to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and/or tumor necrosis factor inhibitors (TNFis) who were prescribed tocilizumab (TCZ) as first-line or second-line biologic treatment in real-world setting.Materials and methods: Data gathered from patients' files was used in a multicenter and retrospective context. Retention rates and the Disease Activity Score in 28 joints with CRP (DAS28-CRP) were evaluated at time points. The relationship of drug efficacy with factors such as smoking, obesity, and previous use of TNFis was also examined.Results: One hundred and twenty-four patients with a median (IQR) RA duration of 3.7 (7.4) years were included. Mean (SD) age was 52.9 (12.9) and 75% of the patients were female. TCZ retention rates in the 6th and 12th months were 94.1% and 86.6%, respectively. In all patients, DAS28-CRP level decreased significantly from baseline to Months 3 and 6. There was an increase in patients with remission and/or low disease activity and a decrease in patients with high disease activity at Month 3 and Month 6 (p < 0.001 for both). Disease activity was similar between subgroups based on body mass index, smoking status, and previous use of TNFis at any time point. Regres-sion analysis showed that absence of concomitant corticosteroid treatment independently was associated with remission/LDA achieve-ment at Month 6 [OR = 0.31, 95% CI (0.14- 0.72), p = 0.006], and Month 12 [OR = 0.35, 95% CI (0.13-0.94), p = 0.037]. Overall, 25 mild adverse events were reported.Conclusion: TCZ was found to be effective and safe in RA patients with IR to csDMARDs and/or TNFis. The drug retention rate was considered satisfactory with more than half of the patients continuing TCZ treatment at Month 12.
  • Küçük Resim Yok
    Öğe
    Surface acoustic wave quasi-Bessel beams generated by symmetrically tilted interdigital transducers
    (Iop Publishing Ltd, 2022) Ulug, Bulent; Kuruoglu, Furkan; Yalcin, Yesim; Erol, Ayse; Sarcan, Fahrettin; Sahin, Ali; Cicek, Ahmet
    Formation of surface acoustic wave (SAW) quasi-Bessel beams on a piezoelectric substrate through superposition of plane waves generated by interdigital transducers tilted symmetrically about the propagation axis is numerically and experimentally demonstrated. Acting as an axicon, the tilted transducers provide a facile way for quasi-Bessel beam generation. Finite-element method simulations reveal that non-diffracting Bessel beams, whose length and width are 193 and 1.38 wavelengths, respectively, can be obtained on a YX-128(circle) lithium niobate substrate for an axicon angle of 15 degrees. The corresponding values for 20 degrees are 146 and 1.05 wavelengths, respectively. For a wavelength of approximately 300 micrometers, transmission spectra show that Bessel beam formation can be achieved at frequencies around 13.3 MHz. Bessel beam is visualized through a thin liquid film of methanol on the substrate. SAW Bessel beams can be utilized in acoustophoresis in microfluidic systems and sensing applications.