358 results
Search Results
Now showing 1 - 10 of 358
Article Citation - WoS: 4Citation - Scopus: 3Insomnia Severity Predicts Psychiatric Symptoms: a Cross-Sectional Study Investigating the Partial Mediations of Worry and Rumination(Routledge Journals, Taylor & Francis Ltd, 2024) Turkarslan, Kutlu Kagan; Cinarbas, Deniz CanelObjective: Insomnia as a disorder on its own or as a symptom of other mental disorders can lead to significant distress and lower quality of life. By exacerbating negative affect and emotion dysregulation, poor sleep and insomnia can contribute to the initiation and maintenance of mental disorders. The aim of this cross-sectional study was to investigate the relationship between insomnia severity and overall psychiatric symptoms (anxiety, depression, obsessive-compulsive symptoms, somatization, phobic anxiety, hostility, interpersonal sensitivity, paranoid ideation, and psychoticism), and the mediational roles of worry and rumination in this relationship. Method: The data was collected from a community sample of 1444 participants (females 69.39%, M-age=27.95, SD=9.37) who completed self-report measures of insomnia severity, worry, rumination, and psychiatric symptoms. The mediational roles of worry and rumination were tested with mediation analysis using the PROCESS Macro. Results: It was found that insomnia severity (beta=0.20, p<.001) significantly predicted psychiatric symptoms directly and via worry and rumination (beta=0.33, p<.001), meaning that worry and rumination partially mediated the relationship between insomnia severity and psychiatric symptoms. The findings were similar after controlling for smoking status, daily screen time, coffee consumption in the evening, weekly exercise frequency, and pre-sleep screen time. Conclusions: Interventions targeting the reduction of insomnia severity and maladaptive emotion regulation strategies (e.g., worry and rumination), as well as the enhancement of adaptive emotion regulation strategies (e.g., positive refocusing and mindfulness), may alleviate the adverse effects of insomnia on psychiatric symptoms.Article Citation - Scopus: 5Micro-Wedm of Ni55.8ti Shape Memory Superalloy: Experimental Investigation and Optimisation(Inderscience Publishers, 2021) Meshri,H.A.M.; Akar,S.; Seyedzavvar,M.; Kiliç,S.E.Nickel-titanium superalloy has gained significant acceptance for engineering applications as orthotropic implants, orthodontic devices, automatic actuators, etc. Considering the unique properties of these alloys, such as high hardness, toughness, strain hardening, and development of straininduced martensite, micro-wire electro-discharge machining (μ-WEDM) process has been accepted as one of the main options for cutting intricate shapes of these alloys in micro-scale. This paper presents the results of a comprehensive study to address the material removal rate (MRR) and surface integrity of Ni55.8Ti shape memory superalloy (SMA) in the μ-WEDM process. The effects of discharge current, pulse on-time, pulse off-time, and servo voltage on the performance of this process, including MRR, white layer thickness, surface roughness, and micro-hardness of the machined surface, were investigated by multi-regression analysis using response surface methodology (RSM). The optimisation of input parameters based on the gradient and the swarm optimisation algorithms were also conducted to maximise the MRR and minimise the white layer thickness, surface roughness, and micro-hardness of the machined samples. © 2021 Inderscience Enterprises Ltd.. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Installation and Performance of the 3rd Veto Plane at the SND@LHC Detector(IOP Publishing Ltd, 2025) Abbaneo, D.; Acampora, G.; Ahmad, S.; Albanese, R.; Alexandrov, A.; Alicante, F.; Zamora Saa, J.During 2022/2023 the optimal inefficiency of the Veto system of the SND@LHC detector was measured to be (7.8 +/- 2.8) x 10(-8). To reduce this inefficiency, a third Veto plane was installed during the 2023-2024 Year End Technical Stop. In addition, the Veto system was lowered to cover the target fully, thereby increasing acceptance. This paper describes how the inefficiency of the Veto system was reduced from (7.8 +/- 2.8) x 10(-8) with an acceptance of about 64% of the target area in 2022-2023 to (4.9 +/- 1.9) x 10(-9) on the full area in 2024.Article Citation - Scopus: 1Production Fragmentation and Transport Mode Choice in Eu-28 Exports(Routledge, 2024) Türkcan,K.; Saygılı,H.This study uses detailed data on exports from the European Union (EU-28) to non-EU countries to investigate the impact of global production fragmentation on the choice of transportation modes. The article finds a positive relationship between production fragmentation and air transportation. The study also finds that air transportation is more likely to be chosen for high-value products. Additionally, the positive effect of production fragmentation on the likelihood of using air transportation is more pronounced when goods are exported to medium-range markets, upper-middle-income countries, countries with better air transportation infrastructure, and time-sensitive products. © 2024 Taylor & Francis Group, LLC.Article Citation - Scopus: 1The Battle of Kars During the Russo-Turkish War (1877- 1878) in V. P. Meshcherskiy's 'caucasian Travel Diary'(İstanbul University Faculty of Letters, 2021) Gülseven,A.Y.; International RelationsTravel notes and memoirs contain many contents that fill the gaps in official history, and are thus precious material for historians as primary sources. This study aims to explore the historical context of the Battle of Kars during the Russo-Turkish War of 1877-1878 by focusing on Vladimir Petrovich Meshcherskiy's travel notes and memoirs on the trip from Moscow to Kars during the war in 1877. Although there is a vast literature on the course and consequences of the Russo-Turkish War of 1877-1878, we have little first-hand information from the field to fill the gaps in our knowledge of the developments during and aftermath of the Kars attack. Meshcherskiy's travel diary does not only provide us with a close-up view of the Eastern front of the Russo-Turkish War, but it also sheds light on the attitude of the local people under the Russian siege. Although this diary provides a rich source of information from the viewpoint of Meshcherskiy, a prominent Russian journalist and novelist, it has never been used in the academic literature on the Russo-Turkish War of 1877-1878. © Turkish Journal of History 2021.Article Citation - WoS: 1Citation - Scopus: 1Chemical Composition Optimization and Isothermal Transformation of Δ-Transformation Plasticity Steel for the Third-Generation Advanced High-Strength Steel Grade(Wiley-v C H verlag Gmbh, 2024) Okur, Onur; Davut, Kemal; Palumbo, Gianfranco; Nalcaci, Burak; Guglielmi, Pasquale; Yalcin, Mustafa Alp; Erdogan, MehmetA new low-manganese transformation-induced plasticity steel is designed with optimized nickel content to achieve superior strength and ductility while minimizing the use of expensive nickel. The steel is optimized using JMatPro software, then cast, and hot rolled. To assess the effect of intercritical annealing on austenite (martensite at room temperature) volume fraction and carbon content, hot-rolled steel samples quenched from different annealing temperatures (680-1100 degrees C) are used. Additionally, hot-rolled steel coupons are intercritically annealed at about 50% austenite formation temperature (740 degrees C) and then subjected to isothermal treatments at 300-425 degrees C for varying times (10-90 min). After optimizing these treatments to maximize retained austenite (RA), tensile specimens are heat-treated first at 740 degrees C and then isothermally at 325 degrees C. Thermodynamic calculations suggest that aluminum combined with silicon may lead to the delta ferrite formation, and even minimal nickel content can stabilize a considerable amount of austenite. In the experimental studies, it is shown that lower-temperature bainitic holding enhances austenite stability by enriching the carbon content. Optimized two-stage heat treatments yield up to 25.8% RA, with a tensile strength of 867.2 MPa and elongation of 40.6%, achieving a strength-elongation product of 35.2 GPax%, surpassing the third-generation advanced high-strength steel grades minimum requirement of 30 GPax%.Article Citation - WoS: 13Citation - Scopus: 13Evaluation of procedural and clinical outcomes of transcatheter aortic valve implantation: A single-center experience(Kare Publ, 2020) Karaduman, Bilge Duran; Kayaoğlu, Hüseyin Ayhan; Keleş, Telat; Bozkurt, EnginObjective: Transcatheter aortic valve implantation (TAVI) is an established alternative to surgical aortic valve replacement. Our study aimed to evaluate the implementation of TAVI at our large-volume center, having an all-comer patient population with short and long-term follow-ups. Methods: This retrospective, single-center analysis included 556 consecutive patients with symptomatic severe aortic stenosis (AS) who underwent TAVI between July 2011 and December 2019. Results: The mean age of the entire population was 77.6±7.9 years, and 54.9% were women. The Society of Thoracic Surgeons (STS) mean score of the cohort was 6.0%±3.5%. The balloon-expandable valve (Sapien XT, Sapien 3; Edwards Lifesciences, Irvine, California) was the most frequently used valves in this cohort (94.6%). Transfemoral access was used in 96.3% of patients. Implantation success was achieved in 96.6% of cases. During the TAVI procedure, 7.2% of patients required permanent pacemaker implantation, with 37.5% in the Lotus valve group needing the most permanent pacemakers. The mean length of hospital stay for the entire cohort was 4.5±2.3 days. Overall, 22 (3.9%) in-hospital deaths occurred before hospital discharge. The mean follow-up period was 15.1±14.9 months for all patients, and a significant improvement was noted in all echocardiographic parameters and functional capacity. Paravalvular leak (PVL) was documented in 18.9% patients, mild in 17.9%, and moderate in 1% at discharge. No cases with severe PVL, necessitating additional procedures. The multiple logistic regression analysis revealed that sex, STS score, baseline SYNTAX score, bicuspid valve morphology, common femoral artery diameter, and post-TAVI PVL were independent predictors of overall mortality. Conclusion: To our knowledge, this study, which is the largest single-center real-world experience of TAVI in Turkey, demonstrated low complication rates with favorable short- and mid-term THV performance in patients undergoing TAVI.Article Citation - WoS: 9Citation - Scopus: 9Sr addition and its effect on the melt cleanliness of A356(Iop Publishing Ltd, 2020) Atakav, Baturalp; Gursoy, Ozen; Erzi, Eray; Tur, Kazim; Dispinar, DeryaStrontium modification of Al-Si alloys has known to have several beneficial effects such as increased feedability, the formation of fibrous Si and increased mechanical properties. However, in the presence of Sr, during melting and holding durations, the oxide structure of the dross may change which leads to several problems during casting operations. In this work, the amount of Sr was changed and the melt was held for 1 h. Reduced Pressure Test (RPT) was used to asses melt quality change and it was found that cleanliness was increased due to the fading of Sr.Article Citation - WoS: 11Citation - Scopus: 15A Study on the Performance Evaluation of Wavelet Decomposition in Transient-Based Radio Frequency Fingerprinting of Bluetooth Devices(Wiley, 2022) Almashaqbeh, Hemam; Dalveren, Yaser; Kara, AliRadio frequency fingerprinting (RFF) is used as a physical-layer security method to provide security in wireless networks. Basically, it exploits the distinctive features (fingerprints) extracted from the physical waveforms emitted from radio devices in the network. One of the major challenges in RFF is to create robust features forming the fingerprints of radio devices. Here, dual-tree complex wavelet transform (DT-CWT) provides an accurate way of extracting those robust features. However, its performance on the RFF of Bluetooth transients which fall into narrowband signaling has not been reported yet. Therefore, this study examines the performance of DT-CWT features on the use of transient-based RFF of Bluetooth devices. Initially, experimentally collected Bluetooth transients from different smartphones are decomposed by DT-CWT. Then, the characteristics and statistics of the wavelet domain signal are exploited to create robust features. Next, the support vector machine (SVM) is used to classify the smartphones. The classification accuracy is demonstrated by varying channel signal-to-noise ratio (SNR) and the size of transient duration. Results show that reasonable accuracy can be achieved (lower bound of 88%) even with short transient duration (1024 samples) at low SNRs (0-5 dB).Article Citation - Scopus: 3Complete Characterization of a Class of Permutation Trinomials in Characteristic Five(Springer, 2024) Grassl,M.; Özbudak,F.; Özkaya,B.; Temür,B.G.In this paper, we address an open problem posed by Bai and Xia in [2]. We study polynomials of the form f(x)=x4q+1+λ1x5q+λ2xq+4 over the finite field F5k, which are not quasi-multiplicative equivalent to any of the known permutation polynomials in the literature. We find necessary and sufficient conditions on λ1,λ2∈F5k so that f(x) is a permutation monomial, binomial, or trinomial of F52k. © The Author(s) 2024.
