Kartezyen hesaplama ağları kullanılarak iki boyutlu sıkıştırılabilir akışlar için laminar navier-stokes çözücüsü geliştirilmesi

TÜBİTAK MAG01.05.201

Predictive value of atrial electromechanical delay for atrial fibrillation recurrence

Background: We investigated the predictive value of atrial electromechanical delay (AEMD) for recurrence of atrial fibrillation (AF) at 1-month after cardioversion.Methods: Seventy-seven patients with persistent AF were evaluated and finally 50 patients (12 men, 38 women) were included. All patients underwent transthoracic electrical DC cardioversion under amiodarone treatment. AEMD was measured as the time interval from the onset of the P wave on electrogram (ECG) to the beginning of late diastolic wave (Am) from the ventricular annulus and atrial walls on tissue Doppler imaging, in the apical 4-chamber view 24 h after cardiversion. P wave maximum-duration (Pmax), P wave minimum-duration (Pmin) and P wave dispersion-duration (Pdis) were calculated on the 12-lead ECG at 24-h postcardioversion. We followed the heart rate and rhythm by 12-lead ECG at 24-h, 1-week and 1-month.Results: At 1-month follow-up after cardioversion, 28 (56%) patients were in sinus rhythm (SR), whereas 22 (44%) patients reverted to AF. The AEMD durations were longer in AF group than SR group (p < 0.001) and were signifi cantly correlated with Pmax and Pdis (p < 0.001 for both). For AF recurrence; duration of AF, left atrial (LA) diameter, maximum LA volume index, mitral A velocity and LA lateral AEMD were significant parameters in univariate-analysis, however LA lateral AEMD was the only significant parameter in multivariate-analysis (OR: 1.46; 95% CI 1.02–2.11; p = 0.03).Conclusions: Our results suggest that AEMD is associated with an increased risk of recurrence of AF within 1-month. These data may have implications for the identification of patients who are most likely to experience substantial benefit from cardiversion therapy for AF

2-D and axisymmetric euler solver for aerodynamic analysis and design

Ph.D. - Doctoral Progra

3D printed poly(epsilon-caprolactone) scaffolds modified with hydroxyapatite and poly(propylene fumarate) and their effects on the healing of rabbit femur defects

A large variety of approaches have been used to treat large and irregular shaped bone defects with less than optimal success due to material or design issues. In recent years patient specific constructs prepared by additive manufacturing provided a solution to the need for shaping implants to fit irregular defects in the surgery theater. In this study, cylindrical disks of poly(e-caprolactone) (PCL) were printed by fused deposition modeling and modified with nanohydroxyapatite (HAp) and poly(propylene fumarate) (PPF) to create a mechanically strong implant with well-defined pore size and porosity, controllable surface hydrophilicity (with PPF) and osteoconductivity (with HAp). Cytotoxicity, irritation and inflammation tests demonstrated that the scaffolds were biocompatible. PCL/HAp and PCL/HAp/PPF scaffolds were implanted in the femurs of rabbits with and without seeding with rabbit Bone Marrow Stem Cells (BMSC) and examined after 4 and 8 weeks with micro-CT, mechanically and histologically. BMSC seeded PCL/HAp/PPF scaffolds showed improved tissue regeneration as determined by bone mineral density and micro-CT. Compressive and tension stiffness values (394 and 463 N mm(-1)) were significantly higher than those of the healthy rabbit femur (316 and 392 N mm(-1), respectively) after 8 weeks of implantation. These 3D implants have great potential for patient-specific bone defect treatments

Foreign direct investment in the Ottoman Empire: Attitudes and political risk

This study examines political risk for foreign direct investment in the Ottoman Empire during the late nineteenth and early twentieth centuries. Such a study has not previously been carried out. Despite many vicissitudes, such as wars and rebellions, the investment climate was more welcoming as compared to neighbouring lands such as Russia and the Balkan countries. While the Ottomans had a corrupt bureaucracy, as in Russia and the Balkans, they were free of xenophobia. Even those Ottoman intellectuals who were against complete freedom in international trade acknowledged the necessity of attracting foreign capital to the country, and suggested policy recommendations.Ottoman Empire, foreign direct investment, political risk, host country attitude, European Powers,