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868 results on '"Cetin, Mustafa"'

8. Max-Min Fair Precoder Design and Power Allocation for MU-MIMO NOMA

Author

Yalcin, Ahmet Zahid, Cetin, Mustafa Kagan, and Yuksel, Melda

Subjects
Electrical Engineering and Systems Science - Signal Processing, Computer Science - Information Theory
Abstract

In this paper, a downlink multiple input multiple output (MIMO) non-orthogonal multiple access (NOMA) wireless communication system is considered. In NOMA systems, the base station has unicast data for all users, and multiple users in a group share the same resources. The objective is to design transmit precoders and power allocation coefficients jointly that provide max-min fairness (MMF) among the strongest users in each group, while maintaining minimum target rates for all the other users. The problem is solved via two main iterative approaches. The first method is based on semi-definite relaxation (SDR) and successive convex approximation (SCA), and the second method is based on the equivalency between achievable rate and minimum mean square error (MMSE) expressions. For the latter approach, Karush-Kuhn-Tucker (KKT) optimality conditions are derived and the expressions satisfied by the optimal receivers, MMSE weights and the optimal precoders are obtained. Proposed algorithms are compared with rate-splitting (RS), orthogonal multiple access (OMA) and multi-user linear precoding (MULP) schemes in terms of MMF rates, energy efficiency and complexity. It is shown that while RS has the best MMF rates and energy efficiency, the MMSE approach based on KKT optimality conditions has the least complexity. Moreover, the SDR/SCA approach offers an excellent tradeoff. It offers high MMF rates, low complexity and superior energy efficiency., Comment: 13 pages, 7 figures

Published
2019

11. Effectiveness of SCORE2 and ASCVD Risk Scores in Combination With Aortic Arch Calcification on Chest Radiograph in Predicting Significant Coronary Artery Disease.

Author

Cetin, Mustafa, Maksutov, Chyngyz, Isakulov, Eldarbek, and Hosoglu, Yusuf

Subjects
*ATHEROSCLEROSIS risk factors, *RISK assessment, *PREDICTIVE tests, *RECEIVER operating characteristic curves, *CARDIOVASCULAR diseases risk factors, *CHEST X rays, *CORONARY artery calcification, *CORONARY angiography, *THORACIC aorta
Abstract

The present study evaluated 10-year atherosclerotic cardiovascular disease (ASCVD) risk using ASCVD and Systematic Coronary Risk Evaluation (SCORE2) risk models in combination with aortic arch calcification (AAC) to identify those at high risk for significant coronary artery disease (CAD) in patients undergoing coronary angiography. Of the 402 patients enrolled, 48 had normal coronary angiograms and served as group 1. The 131 patients with CAD with stenosis of <70% as group 2 and 223 patients with CAD with stenosis of ≥70% as group 3. ASCVD and SCORE2 risk scores, and the presence of AAC differed significantly among these groups. For prediction of significant CAD, the area under the curve (AUC) of ASCVD and SCORE2 risk scores in receiver operating characteristic (ROC) curve analysis were statistically similar ([AUC:.647, P <.001] and [AUC:.654, P <.001], respectively). When AAC was added to ASCVD risk and SCORE2, it increased their predictive value for significant CAD in the ROC curve analysis (P =.003, and P =.019, respectively). In addition, significant net reclassification improvement (NRI) values were obtained by adding AAC to ASCVD and SCORE2 risk models ([NRI =.10, P =.04], and [NRI =.19, P =.04], respectively). These results suggest that the predictive value of ASCVD and SCORE2 increases when AAC is combined. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Alterations in magnetic resonance imaging characteristics of bioabsorbable magnesium screws over time in humans: a retrospective single center study

Author

Sonnow Lena, Ziegler Andreas, Pöhler Gesa H., Kirschner Martin H., Richter Maximilian, Cetin Mustafa, Unal Melih, and Kose Ozkan

Subjects
bioabsorbable implants, magnesium (mg) implants, magnetic resonance imaging (mri), metal artifacts, orthopedic implants, Surgery, RD1-811
Abstract

This study aimed to examine the alterations in magnetic resonance imaging (MRI) characteristics of bioabsorbable magnesium (Mg) screws over time in a single center study in humans.

Published
2021
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17. Repair of Rat Calvarial Bone Defect by Using Exosomes of Umbilical Cord--Derived Mesenchymal Stromal Cells Embedded in Chitosan/Hydroxyapatite Scaffolds.

Author

Bahar, Dilek, Burcin Gonen, Zeynep, Gumusderelioglu, Menemse, Emin Onger, Mehmet, Konuk Tokak, Elvan, Ozturk-Kup, Fatma, Banu Ozkan, Buket, Seda Gokdemir, Nur, and Cetin, Mustafa

Subjects
SKULL surgery, POLYSACCHARIDES, HYDROXYAPATITE, STATISTICS, EXOSOMES, ANIMAL experimentation, IMMUNOHISTOCHEMISTRY, SCANNING electron microscopy, ONE-way analysis of variance, UMBILICAL cord, PLASTIC surgery, RATS, TISSUE engineering, DESCRIPTIVE statistics, BONE regeneration, DATA analysis, DATA analysis software, MESENCHYMAL stem cells, TISSUE scaffolds
Abstract

Purpose: To seek out the bone regeneration effect of human umbilical cord--mesenchymal stem cell (hUC-MSC)--derived exosomes of loaded chitosan/hydroxyapatite (CS/HA) scaffold in a rat calvarium bone regeneration model. Materials and Methods: The hUC-MSC exosomes were purified and characterized. The scaffolds were prepared by a freeze-drying method. Animals were divided into five groups, and the CS/HA/exosome (CS/HA/Exo) scaffolds were transplanted to 5 x 2-mm critical-sized calvarial bone defects for repair in rats. All animals were sacrificed at the postoperative sixth week. Immunohistochemical and histologic analyses were performed. Results: Scanning electron microscopy (SEM) images showed that the exosomes were round-shaped vesicles with bounded membrane, and the diameter of the exosomes was 83.728 ± 27.269 nm. Histologic analysis showed that mean new bone volumes were statistically significantly higher in the CS/HA/Exo group (1.83 ± 0.54, PCS/Exo-CS/HA/Exo = .000), and other new bone volumes in the other groups were statistically significant compared with the control (CS/Exo 1.50 ± 0.14 mm³; CS 1.20 ± 0.43 mm³; control 1.06 ± 0.10 mm³; and CS/HA 1.43 ± 0.66 mm³). Conclusion: The CS/HA/Exo combination is a novel treatment for bone defect repair to induce bone formation. The CS scaffold can significantly promote bone regeneration compared with the control. Moreover, the combination with HA and exosomes is promising for applications in bone tissue regeneration. [ABSTRACT FROM AUTHOR]

Published
2022
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18. Independent relationship between uveitis and increased left atrial volume index in ankylosing spondylitis patients.

Author

Cure, Osman, Ergul, Elif, Cetin, Mustafa, Ilkkilic, Kadir, Kizilkaya, Bayram, and Durak, Serdar

Subjects
ANKYLOSING spondylitis, UVEITIS, ECHOCARDIOGRAPHY, CONFIDENCE intervals, COMORBIDITY
Abstract

Aim: The aim of this study was to evaluate the relationship between uveitis and left atrial volume index (LAVI) in patients with ankylosing spondylitis (AS). Materials and Methods: Demographic, clinical, echocardiographic and brachial artery flow-mediated dilation measurement data of patients diagnosed with AS were recorded prospectively between January 2019 and June 2023. The patients were categorized into two groups: increased (Group 2) and normal (Group 1) based on a cut-off value of 34 ml/m2 for increased LAVI and the data were compared. Results: Of the 89 patients with AS, 54 were male and 35 were female, with a mean age of 42.8±11.8 years. There were N=67 patients in the group with normal LAVI levels, and N=22 patients in the group with high LAVI levels. Mean age, uveitis and comorbid conditions were higher in Group 2. Among the basic echocardiographic parameters that may affect LAVI, only the left ventricular mass index was different in Group 2. In Group 2, flow-dependent dilatation in the vessel decreased. When we evaluated all parameters by multivariate logistic regression analysis, we found that age (odds ratio:1.097; 95% confidence interval:1.017-1.183; P=0.016) and the presence of uveitis (odds ratio:21.3; 95% confidence interval:2.476-182.1; P=0.005) independently predicted Group 2. Conclusion: Evaluation of LAVI in AS patients with uveitis may be a guide in predicting the risk of cardiovascular events and early treatment. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Evaluation of HOTAIR, HOXD8, HOXD9, HOXD11 Gene Expression Levels in Turkish Patients with Acute Myeloid Leukemia and Chronic Myeloid Leukemia: A Single Center Experience

Author

Saraymen, Esma, primary, Erdem, Yakut, additional, Akalin, Hilal, additional, Tascioglu, Nazife, additional, Saraymen, Berkay, additional, Celik, Serhat, additional, Ozdemir, Yesim, additional, Kaynar, Leylagul, additional, Cetin, Mustafa, additional, and Ozkul, Yusuf, additional

Published
2023
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33. Second Allogeneic Stem Cell Transplantation in Acute Leukemia with Post-Transplantation Relapse.

Author

Guven, Zeynep Tuba, Celik, Serhat, Eser, Bulent, Cetin, Mustafa, Unal, Ali, and Kaynar, Leylagul

Subjects
MORTALITY risk factors, CELL transplantation, HOMOGRAFTS, GRANULOCYTE-colony stimulating factor, GRAFT versus host disease, LYMPHOBLASTIC leukemia, LEUKEMIA, CANCER relapse, RETROSPECTIVE studies, BLOOD transfusion reaction, RISK assessment, HEMATOPOIETIC stem cell transplantation, PROGRESSION-free survival, OVERALL survival, DISEASE risk factors
Abstract

Aim: It is known that the prognosis of acute leukemia patients who relapse after the first allogeneic stem cell transplantation (ASCT) is dismal. Our goal was to assess the value of a second allogeneic stem cell transplant in acute leukemia patients who experienced post-transplant recurrence. Material and Methods: We retrospectively reviewed data from 29 patients with relapsing acute leukemia who underwent a second ASCT. Nineteen patients with acute myeloid leukemia and ten patients with acute lymphoblastic leukemia were included in the study. Results: Ten AML patients and 10 ALL patients were included in the study. Most patients (62%) were in remission before the second transplantation. The median time between the first and second ASCT was 11.9 months (3.1-42 months). Complete remission (CR) was achieved after the second ASCT in 21 (72%) patients, and 11 (52%) patients relapsed after the second ASCT. During this analysis, six patients (21%) were alive and in remission. Relapse of the disease was the leading cause of mortality. After the second ASCT, overall survival (OS) was 6.34 months, and leukemia-free survival (LFS) was 13.8 months. Conclusion: For patients with acute leukemia who relapsed after the first ASCT, a second ASCT is a good option and can keep patients alive. [ABSTRACT FROM AUTHOR]

Published
2023
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