01. Araştırma Çıktıları | TR-Dizin | WoS | Scopus | PubMed
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Correction 44th Febs Congress, From Molecules To Living Systems (2019) Posters (vol 9, Pg 65, 2019)(Wiley, 2019) Said, Harun Muayad; Gul, Guler; Akdoğan, Gül; Soysal, Yasemin[Abstract Not Available]Article Citation - WoS: 1Ablation of Atrioventricular Nodal Reentrant Tachycardia With Focal Cryoablation, Compared With Radiofrequency Ablation: Single-Center Experience(Arquivos Brasileiros Cardiologia, 2024) Topaloğlu, Caner; Fici, Francesco; Van de Borne, Philippe; Taşkın, Uğur; Doğduş, Mustafa; Saygı, Serkan; Tengiz, İstemihanBackground: The ablation of atrioventricular nodal reentrant tachycardia (AVNRT) with cryoablation is an alternative to radiofrequency (RF) ablation in patients due to the low risk of total atrioventricular block. An increase in early-late recurrences after cryoablation is reported as an important disadvantage. Objectives: In this study, we aimed to compare the acute procedural success and the long-term recurrence rates of patients, with AVNRT who underwent methods. Methods: 73 patients with AVNRT were included in the study: 32 with cryoablation and 41 with RF ablation. There was no statistically significant difference between acute procedural success in methods. The ablation procedure was performed by an operator experienced in arrhythmology. The choice of RF or cryoablation was made in the electrophysiology laboratory based on the material already available during the procedure. After the procedure, the patients were evaluated every 3 months for 2 years in polyclinic control. The significance level adopted in the statistical analysis was 5%. Results: The 2 groups of patients were homogeneous. The fluoroscopy time (p<0.001) was shorter, but atrium-his (p=0.004) and his-ventricular (p=0.015) times were longer in the cryoablation group. There was no significant difference, in terms of acute procedural success, post-procedure jump without a single echo, and presence of echo and jump. Conclusions: Cryoablation requires less fluoroscopy time and is a safe non-inferior alternative to RF ablation in patients with AVNRT. The risk of AV block is a significant problem with the use of RF energy, making it less suitable for use in young and physically active patients.Article Citation - Scopus: 1Ablation of Atrioventricular Nodal Reentrant Tachycardia With Focal Cryoablation, Compared With Radiofrequency Ablation: Single-Center Experience(2024) Topaloğlu, C.; Fici, F.; Borne, P.V.; Taşkin, U.; Dogdus, M.; Saygi, S.; Tengiz, I.BACKGROUND: The ablation of atrioventricular nodal reentrant tachycardia (AVNRT) with cryoablation is an alternative to radiofrequency (RF) ablation in patients due to the low risk of total atrioventricular block. An increase in early-late recurrences after cryoablation is reported as an important disadvantage. OBJECTIVES: In this study, we aimed to compare the acute procedural success and the long-term recurrence rates of patients, with AVNRT who underwent methods. METHODS: 73 patients with AVNRT were included in the study: 32 with cryoablation and 41 with RF ablation. There was no statistically significant difference between acute procedural success in methods. The ablation procedure was performed by an operator experienced in arrhythmology. The choice of RF or cryoablation was made in the electrophysiology laboratory based on the material already available during the procedure. After the procedure, the patients were evaluated every 3 months for 2 years in polyclinic control. The significance level adopted in the statistical analysis was 5%. RESULTS: The 2 groups of patients were homogeneous.Article Citation - WoS: 9Citation - Scopus: 8Abnormal Cross Frequency Coupling of Brain Electroencephalographic Oscillations Related To Visual Oddball Task in Parkinson's Disease With Mild Cognitive Impairment(Sage Publications Inc, 2023) Bayraktaroglu, Zubeyir; Akturk, Tuba; Yener, Görsev; de Graaf, Tom A.; Hanoglu, Lutfu; Yildirim, Ebru; Gunduz, Duygu HunerliParkinson's disease (PD) is a movement disorder caused by degeneration in dopaminergic neurons. During the disease course, most of PD patients develop mild cognitive impairment (PDMCI) and dementia, especially affecting frontal executive functions. In this study, we tested the hypothesis that PDMCI patients may be characterized by abnormal neurophysiological oscillatory mechanisms coupling frontal and posterior cortical areas during cognitive information processing. To test this hypothesis, event-related EEG oscillations (EROs) during counting visual target (rare) stimuli in an oddball task were recorded in healthy controls (HC; N = 51), cognitively unimpaired PD patients (N = 48), and PDMCI patients (N = 53). Hilbert transform served to estimate instantaneous phase and amplitude of EROs from delta to gamma frequency bands, while modulation index computed ERO phase-amplitude coupling (PAC) at electrode pairs. As compared to the HC and PD groups, the PDMCI group was characterized by (1) more posterior topography of the delta-theta PAC and (2) reversed delta-low frequency alpha PAC direction, ie, posterior-to-anterior rather than anterior-to-posterior. These results suggest that during cognitive demands, PDMCI patients are characterized by abnormal neurophysiological oscillatory mechanisms mainly led by delta frequencies underpinning functional connectivity from frontal to parietal cortical areas.Article Acoustic Emission Response of Macro Synthetic Fibre Reinforced Concrete Beams(Natl Inst Science Communication-Niscair, 2025) Selman, Efe; Kilic, GokhanMacro synthetic fibre reinforced concrete(MSFRC) has been frequently preferred owing to their adequate ductility, post cracking capacity and toughness values, being potential sustainable alternative material to steel fibre concrete. Their fracture processes and possible failure mechanisms have been simultaneously scrutinized in order to fully exploit from their advantageous structural characteristics. AE methods have accurately provided comprehensive information on the origination and development of a flaw that is located in inner sections of material. With this current study, AE technique has been selected in order to determine the crack evolution and propagation in MSFRC structures. To study the AE response of MSFRC specimens, three MSFRC specimens in the volumetric ratios 0.5%,1% and 1.5% have been prepared and tested with reference concrete specimen. Average frequency, RA(Rise time to Amplitude ratio) and Sentry function parameters have been examined during three-point bending tests for specimens. AE features which correspond to the damage occurrences have been identified and shown during load history. AE method has been found to predict adequately the damage progression of MSFRC elements and the experimental behaviours of specimens have been typically captured well.Conference Object Citation - WoS: 2Citation - Scopus: 2Active Particle Aggregate on Complex Bubble Surfaces(Canadian Science Publishing, Nrc Research Press, 2018) Akguc, Gursoy B.Recently, colloids have been shown to form complex structures on bubble surfaces on demand. With the help of a high power pulse laser shining on a thin water film, water bubbles can be formed and heat unbalance creates a convective flow, which carries colloids on the surface of these water bubbles to form aggregates. Here, active particles are studied in a similar setup and conditions are laid out to form aggregates on water bubble surfaces. The effect of motility and chirality of active particles on formation of aggregate are discussed. The simulation results obtained here will hopefully help the experimental endeavors in future.Article Citation - WoS: 14Citation - Scopus: 18Adaptive Controller Based on Grid Impedance Estimation for Stable Operation of Grid-Connected Inverters Under Weak Grid Conditions(Inst Engineering Technology-Iet, 2020) Temiz, Hakan; Keysan, Ozan; Demirok, ErhanAn electric grid having high impedance seen from the connection point is considered as a weak grid and it adversely affects the system stability of grid-tied voltage source inverters in renewable power devices. In this study, an adaptive controller is proposed by configuring the settling time of the phase-locked loop based on the estimated grid impedance. Pseudorandom binary sequence injection and Fourier techniques are carried out for grid impedance estimation. Impedance-based stability analysis is performed for a predetermined steady-state operation point. The proposed method is verified by a 300-kVA inverter prototype for wide-range grid impedance varying from 0.3 to 3 mH.Article Citation - WoS: 1Adaptive Video Streaming With H.264 Sp Frames(Pamukkale Univ, 2012) Sayit, Muge; Tunali, E. ThrhanIn this work, SP frames of the extended profile of H.264 AVC video codec are utilized to obtain efficient switching for actual video streaming experiments on the Internet. An adaptive algorithm is developed and by using this algorithm, performance of SP frames is compared with that of standard I-frame switching. Detailed measurements of network conditions are given for each experiment to indicate that comparisons are carried out in fair conditions. It has been observed that, under certain conditions, SP frames can improve performance considerably whereas in the others, they may only introduce overhead. Based on this observation different GOP patterns are proposed for different video type-congestion level combinations.Article Citation - WoS: 6Citation - Scopus: 5Adaptive, Incentive and Scalable Dynamic Tree Overlay for P2p Live Video Streaming(Springer, 2016) Sayit, Muge; Demirci, Sercan; Kaymak, Yagiz; Tunali, E. TurhanIn this paper, we propose a new multicast tree framework to be used in peer-to-peer (P2P) live video streaming systems. The proposed system, adapts the tree links under high peer churn and runs in a totally distributed manner. In order to provide this dynamism and seamless streaming at the same time, we propose a cross layer design involving scalable video codec, backup parents and hierarchical clusters. The performance of the system is measured in real world environment PlanetLab that has nodes distributed all over the world. The experiments show that the proposed system provides high quality of experience (QoE) in terms of Peak Signal to Noise Ratio (PSNR), playback delay and duration of pauses. The proposed system also provides incentive mechanism to its users.Article Citation - WoS: 2Citation - Scopus: 2Adrenomedullin Has No Effect on Segmental Bone Defect Healing but Increases Bone Mineral Density in Rat Model(AVES, 2023) Kaymakoğlu, Mehmet; Ciftci, E.; Korkusuz, P.; Ozdemir, E.; Erden, M.E.; Turhan, E.Objective: This study aimed to investigate the effect of adrenomedullin on the healing of the segmental bone defect in a rat model. Methods: Thirty-six Wistar rats were randomly divided into 6 groups based on follow-up periods and administered a dose of adreno-medullin hormone. In each group, bilaterally, a 2-mm bone defect was created at the diaphysis of the radius. Sodium chloride solution was administered to sham groups 3 times a week for 4 and 8 weeks intraperitoneally. Adrenomedullin was administered to the study groups 3 times a week: 15 μg—4 weeks, 15 μg—8 weeks, 30 μg—4 weeks, and 30 μg—8 weeks, respectively. After euthanasia, the segmental defects were evaluated by histomorphometric [new bone area (NBA)] and microtomographic [bone volume (BV), bone surface (BS), and bone mineral density (BMD)] analyses. Results: Although the 4-and 8-week 15 μg administered study groups had higher NBA values than the other study and control groups, the histomorphometric analysis did not reveal any statistical difference between the control and study groups regarding NBA (P >.05). In microtomographic analysis, BV was higher in the 15 μg 4-week group than 30 μg 4-week group (296.9 vs. 208.5, P =.003), and BS was lower in the 30 μg 4-week group than in the 4-week control group (695.5 vs. 1334.7, P =.005), but overall, no significant difference was found between the control and study groups (P >.05). Despite these minor differences in histomorphometric and microtomographic criteria indicating new bone formation, the BMD values of the 15 μg 8-week study group showed a significant increase compared with the control group (P =.001, respectively). Conclusion: Adrenomedullin positively affected BMD at 15 μg, but this study could not show healing in the segmental defect site at different dose regimens. Further studies are needed to assess its effects on bone tissue trauma. © 2023, AVES. All rights reserved.Article Citation - WoS: 7Citation - Scopus: 9Adults' Visual Cue Preferences and Wayfinding Abilities in Healthcare Centers(Sage Publications Inc, 2023) Asli, Afsaneh Alizadeh; Moshfeghifar, Samaneh; Mousighichi, Pouya; Samimi, Paniz MousaviObjectives: Physical and visual elements that help people find their way around an environment are called visual cues (VCs). The current study aims to evaluate adults' wayfinding abilities (navigation, orientation, spatial anxiety, and distance estimation) and VC (navigational color coding) preferences in terms of color and position; additionally, investigates their differences in adults' life span phases (young adults, early middle-aged adults, and late middle-aged adults). Background: Wayfinding in complex environments such as healthcare centers has been challenging for most people. Although VCs are being used increasingly to facilitate wayfinding, considering people's preferences regarding VCs, especially navigational color coding, are neglected. Methods: Obtained data from a survey of 375 healthcare center visitors with textual and photo questionnaires were analyzed by descriptive statics and one-way analysis of variance. Results: Young adults preferred VCs with mixed colors and positioned in the middle of the floor, early middle-aged adults preferred warm color VCs in the middle of the wall, and late middle-aged adults preferred warm color VCs at the bottom of the wall. Additionally, the results demonstrated that with aging, navigation and distance estimation abilities deteriorate, and spatial anxiety increases. Conclusions: The outcomes of the present study increase our knowledge regarding the impact of adults' life span phases on their wayfinding abilities and VC preferences and offer suggestions for architects and healthcare center stakeholders to provide environments that improve adults' wayfinding.Article Citation - WoS: 2Citation - Scopus: 2Age-Related Aspects of Sex Differences in Event-Related Brain Oscillatory Responses: a Turkish Study(Mdpi, 2024) Yener, Görsev; Kıyı, İlayda; Düzenli-Öztürk, Seren; Yerlikaya, DenizEarlier research has suggested gender differences in event-related potentials/oscillations (ERPs/EROs). Yet, the alteration in event-related oscillations (EROs) in the delta and theta frequency bands have not been explored between genders across the three age groups of adulthood, i.e., 18-50, 51-65, and >65 years. Data from 155 healthy elderly participants who underwent a neurological examination, comprehensive neuropsychological assessment (including attention, memory, executive function, language, and visuospatial skills), and magnetic resonance imaging (MRI) from past studies were used. The delta and theta ERO powers across the age groups and between genders were compared and correlational analyses among the ERO power, age, and neuropsychological tests were performed. The results indicated that females displayed higher theta ERO responses than males in the frontal, central, and parietal regions but not in the occipital location between 18 and 50 years of adulthood. The declining theta power of EROs in women reached that of men after the age of 50 while the theta ERO power was more stable across the age groups in men. Our results imply that the cohorts must be recruited at specified age ranges across genders, and clinical trials using neurophysiological biomarkers as an intervention endpoint should take gender into account in the future.Article Citation - WoS: 4Citation - Scopus: 4All Colors Shortest Path Problem on Trees(Springer, 2018) Akcay, Mehmet Berkehan; Akcan, Hüseyin; Evrendilek, CemGiven an edge weighted tree T(V, E), rooted at a designated base vertex , and a color from a set of colors assigned to every vertex , All Colors Shortest Path problem on trees (ACSP-t) seeks the shortest, possibly non-simple, path starting from r in T such that at least one node from every distinct color in C is visited. We show that ACSP-t is NP-hard, and also prove that it does not have a constant factor approximation. We give an integer linear programming formulation of ACSP-t. Based on a linear programming relaxation of this formulation, an iterative rounding heuristic is proposed. The paper also explores genetic algorithm and tabu search to develop alternative heuristic solutions for ACSP-t. The performance of all the proposed heuristics are evaluated experimentally for a wide range of trees that are generated parametrically.Article Citation - WoS: 36Citation - Scopus: 39Alteration of Mirnas in Small Neuron-Derived Extracellular Vesicles of Alzheimer's Disease Patients and the Effect of Extracellular Vesicles on Microglial Immune Responses(Springernature, 2022) Durur, Devrim Yagmur; Tastan, Bora; Tufekci, Kemal Ugur; Olcum, Melis; Uzuner, Hamdiye; Karakulah, Gokhan; Yener, GörsevAlzheimer's disease (AD) is one of the most severe neurodegenerative diseases observed in the elderly population. Although the hallmarks of AD have been identified, the methods for its definitive diagnosis and treatment are still lacking. Extracellular vesicles (EVs) have become a promising source for biomarkers since the identification of their content. EVs are released from multiple cell types and, when released from neurons, they pass from the brain to the blood with their cargo molecules. Hence, neuron-specific EV-resident microRNAs (miRNAs) are promising biomarkers for diagnosis of AD. This study aimed to identify altered miRNA content in small neuron-derived extracellular vesicles (sNDEVs) isolated from AD patients and healthy individuals. Furthermore, we examined the role of sNDEV-resident miRNAs in neuron-glia cellular interaction to understand their role in AD propagation. We identified 10 differentially expressed miRNAs in the sNDEVs of patients via next-generation sequencing and validated the most dysregulated miRNA, let-7e, with qRT-PCR. Let-7e was significantly increased in the sNDEVs of AD patients compared with those of healthy controls in a larger cohort. First, we evaluated the diagnostic utility of let-7e via ROC curve analysis, which revealed an AUC value of 0.9214. We found that IL-6 gene expression was increased in human microglia after treatment with sNDEVs of AD patients with a high amount of let-7e. Our study suggests that sNDEV-resident let-7e is a potential biomarker for AD diagnosis, and that AD patient-derived sNDEVs induce a neuroinflammatory response in microglia.Article Citation - WoS: 1Alternative Controller Design for Rotary Inverted Pendulum(Univ North, 2018) Oksuz, Mehmet; Onal, Mehmet Burak; Halicioglu, Recep; Dulger, Lale CananThe inverted pendulum has been considered a classical control problem. Two designs of inverted pendulum are planar and rotary with a nonlinear unstable system characteristic. Inverted pendulum systems are nonlinear. They can be used for testing and studying various observers and controllers. Control of a rotary inverted pendulum is studied here. This paper proposes stabilization of the rotary inverted pendulum at its upright position by using full-state controller. Full-state controllers are designed by using different damping ratios. MATLAB simulation results and the experimental results are taken for 10 degrees step for 5 seconds. The best controller is chosen for SRV02-Rotary inverted pendulum by looking at the simulation and experimental results.Article Citation - WoS: 1Analysis of Joint Reliability Importance in Linear M-Consecutive L-Out System(Ankara Univ, Fac Sci, 2020) Kan, Cihangir; Ozkut, MuratCombinatorial techniques have an important role to compute the joint reliability importance (JRI) of some coherent systems. We obtain combi- natorial formula for calculation of the JRI of two components in a generalised version of consecutive type systems consisting of n linearly ordered components such that system fails if and only if (i§) there are at least m l-overlapping runs of k consecutive failed components (n m(k l) + l; l < k). Overlapping runs mean having common elements which is denoted by l: We concentrate on both s-independent & identical components and exchangeable components. Explicit combinatorial formulae are provided for computing the JRI of the above mentioned cases. For both cases, we also compare the results with lin- ear m-consecutive-k-out-of-n:F system (nonoverlapping case when l = 0). In addition, some numerical and illustrative examples are presented.Article Citation - WoS: 14Citation - Scopus: 12Analysis of Risk Factors Affecting Mortality in Elderly Patients Operated on for Hip Fractures: a Retrospective Comparative Study(Turkish Assoc Orthopaedics Traumatology, 2021) Biçen, Ahmet Çağdaş; Akdemir, Mehmet; Turken, Mehmet Aykut; Cekok, Kubra; Ekin, Ahmet; Turan, Ahmet CemilObjective: The aims of this study were (1) to investigate the effects of different demographic and perioperative modalities on mortality rates and (2) to compare mortality rates between different implants in elderly patients operated on for hip fractures. Methods: In this retrospective study, a total of 314 patients who were operated on for hip fractures were included study. Patients were then divided into four groups based in their implant types: long-stem cementless bipolar hemiarthroplasty (n = 124; 102 female, 22 male; mean age = 84.2 +/- 6.4 years), standard-stem cementless bipolar hemiarthroplasty (n = 74; 48 female, 26 male; mean age = 83.5 +/- 6.9 years), antegrade intertrochanteric nail (n = 61; 35 female, 26 male; mean age = 78.5 +/- 6.8 years), and total hip arthroplasty (n = 55; 34 female, 21 male; mean age = 72.5 +/- 4.3 years). Data including gender, age, duration from injury to surgery, American Society of Anesthesiologists (ASA) score, comorbidities, use of antiplatelet agents, Barthel Index of Activities of Daily Living, type of anesthesia, operation time, preoperative hemoglobin values, blood transfusions given, duration of hospital stay, complications, and type of fracture were recorded. Results: Overall, the mean follow-up was 36.5 (range = 0 - 107) months. The overall mortality rate was 53.2%. The median survival duration was 44.2 +/- 5 months (range = 34.3 - 54). Survival rates were found significantly different among the groups (P = 0.001). In the first three years postoperatively, the mortality rate was higher in the standard-stem bipolar hemiarthroplasty group, but in the long-term follow-up, the long-stem bipolar hemiarthroplasty group exhibited the higher mortality rates. It was observed that some parameters had statistically significant effects on the mortality rates. Male gender, higher age, lower hemoglobin values, increased number of blood transfusions, ASA scores >= 3, the existence of >= 3 comorbidities were found as main predictors of increased mortality rates. Conclusion: The results of this study have shown that age, gender, preoperative hemoglobin levels, ASA scores, and comorbidities are significant factors affecting mortality in elderly patients operated on for hip fractures. Long-stem cementless bipolar hemiarthroplasty appears to show similar rates of mortality with standard-stem cementless bipolar hemiarthroplasty.Article Citation - WoS: 4Citation - Scopus: 5Analysis of Three Mutations in Italian Strains of Sars-Cov Implications for Pathogenesis(Karger, 2021) Benvenuto, Domenico; Benedetti, Francesca; Demir, Ayse Banu; Ciccozzi, Massimo; Zella, DavideBackground: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped virus initially detected in Wuhan in December 2019, responsible for coronavirus disease 2019 (COVID-19), a respiratory syndrome currently affecting >220 countries around the world, with >80 million cases registered and >1.8 million deaths. Objective: As several vaccines are still being developed and 2 have been approved, it is particularly important to perform evolutionary surveillance to identify mutations potentially affecting vaccine efficacy. Methods: DynaMut server has been used to evaluate the impact of the mutation found on SARS-CoV-2 isolates available on GISAID. Results: In this article, we analyze whole genomes sequenced from Italian patients, and we report the characterization of 3 mutations, one of which presents in the spike protein. Conclusion: The mutations analyzed in this article can be useful to evaluate the evolution of SARS-CoV-2.Article Citation - WoS: 2Citation - Scopus: 2An Analysis of Turkey's Accession To the European Union(Wiley, 2013) Oezguezer, Guel Ertan; Pensieroso, LucaWe build a two-country dynamic general equilibrium model to study whether European citizens would benefit from the eventual accession of Turkey to the European Union (EU). The results of the simulations show that Turkey's accession is welfare enhancing for Europeans, provided that Turkish total factor productivity (TFP) increases sufficiently after enlargement. In the benchmark model with no capital mobility, the Europeans are better off if the Turkish TFP increase bridges more than 21% of the initial TFP gap between Turkey and the EU. This figure increases to 33% when capital mobility is introduced.Article Citation - WoS: 3Citation - Scopus: 3Analyzing the Multi-State System Under a Run Shock Model(Cambrıdge Unıv Press, 2024) Özkut, Cemal Murat; Kan, Cihangir; Franko, CekiA system experiences random shocks over time, with two critical levels, d1 and d2, where $d_{1} \lt d_{2}$. k consecutive shocks with magnitudes between d1 and d2 partially damaging the system, causing it to transition to a lower, partially working state. Shocks with magnitudes above d2 have a catastrophic effect, resulting in complete failure. This theoretical framework gives rise to a multi-state system characterized by an indeterminate quantity of states. When the time between successive shocks follows a phase-type distribution, a detailed analysis of the system's dynamic reliability properties such as the lifetime of the system, the time it spends in perfect functioning, as well as the total time it spends in partially working states are discussed.
