Browsing by Author "Unlu, Mehmet Burcin"

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Atrial fibrillation designation with micro-Raman spectroscopy and scanning acoustic microscope
(NATURE PORTFOLIO, 2022-01-01) Parlatan, Ugur; Parlatan, Seyma; Sen, Kubra; Kecoglu, Ibrahim; Ulukan, Mustafa Ozer; Karakaya, Atalay; Erkanli, Korhan; Turkoglu, Halil; Ugurlucan, Murat; Unlu, Mehmet Burcin; Tanoren, Bukem
Atrial fibrillation (AF) is diagnosed with the electrocardiogram, which is the gold standard in clinics. However, sufficient arrhythmia monitoring takes a long time, and many of the tests are made in only a few seconds, which can lead arrhythmia to be missed. Here, we propose a combined method to detect the effects of AF on atrial tissue. We characterize tissues obtained from patients with or without AF by scanning acoustic microscopy (SAM) and by Raman spectroscopy (RS) to construct a mechano-chemical profile. We classify the Raman spectral measurements of the tissue samples with an unsupervised clustering method, k-means and compare their chemical properties. Besides, we utilize scanning acoustic microscopy to compare and determine differences in acoustic impedance maps of the groups. We compared the clinical outcomes with our findings using a neural network classification for Raman measurements and ANOVA for SAM measurements. Consequently, we show that the stiffness profiles of the tissues, corresponding to the patients with chronic AF, without AF or who experienced postoperative AF, are in agreement with the lipid-collagen profiles obtained by the Raman spectral characterization.
Carotid artery plaque structure in the context of symptomatic/asymptomatic nature of carotid artery stenosis
(CZECH SOC CARDIOLOGY \& CZECH SOC CARDIOVASCULAR SURGERY, 2021-01-01) Oztas, Didem Melis; Bilen, Bukem Tanoren; Sener, Leyla Turker; Beyaz, Metin Onur; Ulukan, Mustafa Ozer; Unal, Orcun; Unlu, Mehmet Burcin; Reis, Paulo Eduardo Ocke; Ugurlucan, Murat
Objective: In this paper, we examined the relationship between atherosclerotic plaque characteristics and symptomatic carotid artery disease. Material and methods: Twenty-two patients who underwent carotid endarterectomy were enrolled into the study. Thirteen patients were male and remaining 9 patients were female. The mean age was 60.2 +/- 9.6 years. The carotid artery stenosis ranged between 75\% and 99\%. Eight patients were asymptomatic and remaining 14 patients were symptomatic. Ten patients suffered stroke. One of them had recurrent transient ischemic attacks, 4 patients had dizziness, and one of them had amaurosis fugax. The extracted plaques were evaluated by scanning acoustic microscopy (SAM) and micro-computerized tomography (micro-CT). Results: Smaller acoustic impedance values that reveal collagen-rich plaque formation were detected in patients who had stroke, while higher acoustic impedance values that reveal calcium-rich plaque formation were detected in the asymptomatic patients' plaques. Conclusions: Determination of plaque characteristics with modern radiographic techniques, rather than relying on the degree of stenosis in patients with carotid artery disease, may be helpful to discriminate patients requiring intervention.
Raman spectroscopy as a non-invasive diagnostic technique for endometriosis
(NATURE PUBLISHING GROUP, 2019-01-01) Parlatan, Ugur; Inanc, Medine Tuna; Ozgor, Bahar Yuksel; Oral, Engin; Bastu, Ercan; Unlu, Mehmet Burcin; Basar, Gunay
Endometriosis is a condition in which the endometrium, the layer of tissue that usually covers the inside of the uterus, grows outside the uterus. One of its severe effects is sub-fertility. The exact reason for endometriosis is still unknown and under investigation. Tracking the symptoms is not sufficient for diagnosing the disease. A successful diagnosis can only be made using laparoscopy. During the disease, the amount of some molecules (i.e., proteins, antigens) changes in the blood. Raman spectroscopy provides information about biochemicals without using dyes or external labels. In this study, Raman spectroscopy is used as a non-invasive diagnostic method for endometriosis. The Raman spectra of 94 serum samples acquired from 49 patients and 45 healthy individuals were compared for this study. Principal Component Analysis (PCA), k- Nearest Neighbors (kNN), and Support Vector Machines (SVM) were used in the analysis. According to the results (using 80 measurements for training and 14 measurements for the test set), it was found that kNN-weighted gave the best classification model with sensitivity and specificity values of 80.5\% and 89.7\%, respectively. Testing the model with unseen data yielded a sensitivity value of 100\% and a specificity value of 100\%. To the best of our knowledge, this is the first study in which Raman spectroscopy was used in combination with PCA and classification algorithms as a non-invasive method applied on blood sera for the diagnosis of endometriosis.