Browsing by Author "Erdogan, Onur"

Now showing 1 - 2 of 2

Evaluation of Strength Parameters and Quality Assessment of Different Lithotype Levels of Edremit (Van) Travertine (Eastern Turkey)
(Pergamon-elsevier Science Ltd, 2015) Erdogan, Onur; Ozvan, Ali
Travertine deposits have an economic value due to their chemical composition and widespread use in the construction industry. Travertines reveal different lithotypes depending on their depositional process and this can affect mechanical and engineering properties of travertine. Edremit travertine displays various structural features in lateral and vertical distributions. In this study, Edremit travertine is firstly differentiated into three different levels such as crystalline crust, shrub and reed based on the mechanical, physical properties and field observations. A strength map of different lithotypes is prepared and crystalline crust level is investigated for using in marble industry. For this purpose, the long-term performance/durability of crystalline crust travertine is investigated against various environmental processes by using several accelerated weathering tests. Accordingly, compared to the crystalline crust other levels of travertine (shrub and reed) are much more affected from atmospheric conditions. Among these levels, the crystalline crust level is recommended to be used as marble according to laboratory test results whereas other levels are appropriate for cement industry. (C) 2015 Elsevier Ltd. All rights reserved.
A New Biomarker That Predicts Ventricular Arrhythmia in Patients With Ischemic Dilated Cardiomyopathy: Galectin-3
(Elsevier Espana Slu, 2021) Erdogan, Onur; Karaayvaz, Ekrem; Erdogan, Tugba; Panc, Cafer; Oncul, Aytac; Bilge, Ahmet Kaya; Sarikaya, Remzi
Introduction: Ventricular arrhythmias are caused by scar tissue in patients with ischemic dilated cardiomyopathy. The gold standard imaging technique for detecting scar tissue is magnetic resonance imaging (MRI). However, MRI is not feasible for use as a screening test, and also cannot be used in patients who have received an implantable cardioverter-defibrillator (ICD). In this study, we aimed to assess the association between levels of galectin-3 (Gal-3), which is known to be secreted by scar tissue, and the history of ventricular arrhythmias in patients with ischemic dilated cardiomyopathy who received an ICD. Methods: Nineteen healthy controls and 32 patients who had previously undergone VVI-ICD implantation due to ischemic dilated cardiomyopathy were enrolled in the study. Patients were divided into three groups: the first group including patients who had received no ICD therapies, the second including patients with arrhythmia requiring therapies with no arrhythmia storm, and the third including patients who had arrhythmia storm. We assessed the association between Gal-3 levels and the history of ventricular arrhythmias in these patients. Results: Gal-3 levels were significantly higher in the patient groups than in the control group (p<0.01). Gal-3 levels of patients with arrhythmias requiring ICD therapies were significantly higher than in patients with ICD not requiring therapies (p=0.02). They were also higher in patients with a history of arrhythmia storm than in patients without shocks (p=0.05). Receiver operating curve analysis showed with 84% sensitivity and 75% specificity that Gal-3 levels over 7 ng/ml indicated ventricular arrhythmia that required therapies.