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  • Article
    Citation - WoS: 10
    Citation - Scopus: 11
    Fixed Point Theorems Via Auxiliary Functions
    (Hindawi Publishing Corporation, 2012) Karapinar, Erdal; Salimi, Peyman
    We prove new fixed point theorems in the framework of partially ordered metric spaces. The main result is an extension and a generalization of many existing results in the literature. An example is also considered to illustrate the main result.
  • Article
    Transcatheter Aortic Valve Implantation in Nonagenarians: A Comparative Analysis of Baseline Characteristics and 1-Year Outcomes
    (MDPI, 2025) Guney, Murat Can; Bozkurt, Engin
    Background: Transcatheter aortic valve implantation (TAVI) is increasingly used in elderly patients with severe aortic stenosis, yet data on nonagenarians remain limited. This study aimed to compare clinical characteristics and outcomes of patients aged >= 90 years with those aged <90 years undergoing TAVI. Methods: We retrospectively analyzed 620 patients who underwent transfemoral TAVI. Patients were divided into two groups: <90 years (n = 545) and >= 90 years (n = 75). Baseline clinical, procedural, and outcome data were compared. Results: Nonagenarians had lower body mass index (BMI) and a lower prevalence of comorbidities such as diabetes, hyperlipidemia, and prior coronary artery bypass grafting CABG (all p < 0.05). All-cause mortality was higher in nonagenarians at 1 month (8.0% vs. 5.5%, p = 0.425), 6 months (9.3% vs. 7.9%, p = 0.838), and 1 year (21.3% vs. 16.7%, p = 0.405), though these differences were not statistically significant. In-hospital stroke occurred more frequently in patients >= 90 years (6.7% vs. 2.2%, p = 0.044). Conclusions: Despite a higher rate of in-hospital stroke, nonagenarians undergoing TAVI had comparable mortality outcomes to younger patients. These findings support the feasibility of TAVI in selected very elderly patients, while highlighting the need for tailored stroke prevention strategies. Trial Registration: The trial is retrospectively registered, and a clinical trial number is not applicable.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Optimized Porous Carbon Particles From Sucrose and Their Polyethyleneimine Modifications for Enhanced Co2 Capture
    (Mdpi, 2024) Ari, Betul; Inger, Erk; Sunol, Aydin K.; Sahiner, Nurettin
    Carbon dioxide (CO2), one of the primary greenhouse gases, plays a key role in global warming and is one of the culprits in the climate change crisis. Therefore, the use of appropriate CO2 capture and storage technologies is of significant importance for the future of planet Earth due to atmospheric, climate, and environmental concerns. A cleaner and more sustainable approach to CO2 capture and storage using porous materials, membranes, and amine-based sorbents could offer excellent possibilities. Here, sucrose-derived porous carbon particles (PCPs) were synthesized as adsorbents for CO2 capture. Next, these PCPs were modified with branched- and linear-polyethyleneimine (B-PEI and L-PEI) as B-PEI-PCP and L-PEI-PCP, respectively. These PCPs and their PEI-modified forms were then used to prepare metal nanoparticles such as Co, Cu, and Ni in situ as M@PCP and M@L/B-PEI-PCP (M: Ni, Co, and Cu). The presence of PEI on the PCP surface enables new amine functional groups, known for high CO2 capture ability. The presence of metal nanoparticles in the structure may be used as a catalyst to convert the captured CO2 into useful products, e.g., fuels or other chemical compounds, at high temperatures. It was found that B-PEI-PCP has a larger surface area and higher CO2 capture capacity with a surface area of 32.84 m(2)/g and a CO2 capture capacity of 1.05 mmol CO2/g adsorbent compared to L-PEI-PCP. Amongst metal-nanoparticle-embedded PEI-PCPs (M@PEI-PCPs, M: Ni, Co, Cu), Ni@L-PEI-PCP was found to have higher CO2 capture capacity, 0.81 mmol CO2/g adsorbent, and a surface area of 225 m(2)/g. These data are significant as they will steer future studies for the conversion of captured CO2 into useful fuels/chemicals.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 9
    Electronic, Optical and Thermodynamic Characteristics of Bi12sio20 Sillenite: First Principle Calculations
    (Elsevier Science Sa, 2021) Isik, M.; Surucu, G.; Gencer, A.; Gasanly, N. M.
    Bi12XO20 (X: Si, Ge, Ti) ternary semiconducting compounds are known as sillenites and take a remarkable attention thanks to their attractive photorefractive properties. The present paper reports electronic, optical and thermodynamic characteristics of Bi12SiO20 by means of density functional theory (DFT) calculations. The crystalline structure of the compound was revealed as cubic with lattice constant of 10.135 angstrom. XRD pattern obtained from DFT calculations were compared with experimental data and there is a good consistency between them. The electronic band structure and density of state plots were presented in detail. The band gap energy of the compound was determined from electronic band structure and spectra of optical constants. The spectral dependencies of real and imaginary components of dielectric function, refractive index, extinction coefficient, absorption coefficient and loss function were plotted in the 0-12 eV spectral range. The revealed structural, electronic and optical characteristics were discussed taking into account the previously reported theoretical and experimental studies on the Bi12SiO20 sillenite.
  • Article
    Mobile Payment Adoption During the COVID-19 Pandemic: A Systematic Literature Review
    (Palgrave Macmillan Ltd, 2026) Belbag, Aybegum Gungordu; Güngördü Belbağ, Aybegüm
    During the pandemic, the shift to non-physical transactions increased the need for mobile payments. This study aims to offer a systematic literature review on consumer behavior towards mobile payment during the pandemic, using the Theory, Context, Characteristics, and Methodology framework and following the Scientific Procedures and Reasons for Systematic Literature Reviews protocol. 47 articles from the WOS database were analyzed, revealing a dominance of quantitative studies, primarily based on the Technology Acceptance Model and UTAUT. Findings show that environmental stimuli and internal states (organism) shape behaviors and behavioral intentions (responses) towards mobile payments during the pandemic. The study concludes with future research directions grounded in the TCCM framework.
  • Article
    Citation - WoS: 58
    Citation - Scopus: 66
    Country-Level and Individual-Level Predictors of Men's Support for Gender Equality in 42 Countries
    (Wiley, 2020) Kosakowska-Berezecka, Natasza; Besta, Tomasz; Bosson, Jennifer K.; Jurek, Pawel; Vandello, Joesph A.; Best, Deborah L.; Zukauskiene, Rita
    Men sometimes withdraw support for gender equality movements when their higher gender status is threatened. Here, we expand the focus of this phenomenon by examining it cross-culturally, to test if both individual- and country-level variables predict men's collective action intentions to support gender equality. We tested a model in which men's zero-sum beliefs about gender predict reduced collective action intentions via an increase in hostile sexism. Because country-level gender equality may threaten men's higher gender status, we also examined whether the path from zero-sum beliefs to collective action intentions was stronger in countries higher in gender equality. Multilevel modeling on 6,734 men from 42 countries supported the individual-level mediation model, but found no evidence of moderation by country-level gender equality. Both country-level gender equality and individual-level zero-sum thinking independently predicted reductions in men's willingness to act collectively for gender equality.
  • Article
    Citation - WoS: 19
    Citation - Scopus: 24
    A Novel Hybrid Machine Learning Based System To Classify Shoulder Implant Manufacturers
    (Mdpi, 2022) Sivari, Esra; Guzel, Mehmet Serdar; Bostanci, Erkan; Mishra, Alok
    It is necessary to know the manufacturer and model of a previously implanted shoulder prosthesis before performing Total Shoulder Arthroplasty operations, which may need to be performed repeatedly in accordance with the need for repair or replacement. In cases where the patient's previous records cannot be found, where the records are not clear, or the surgery was conducted abroad, the specialist should identify the implant manufacturer and model during preoperative X-ray controls. In this study, an auxiliary expert system is proposed for classifying manufacturers of shoulder implants on the basis of X-ray images that is automated, objective, and based on hybrid machine learning models. In the proposed system, ten different hybrid models consisting of a combination of deep learning and machine learning algorithms were created and statistically tested. According to the experimental results, an accuracy of 95.07% was achieved using the DenseNet201 + Logistic Regression model, one of the proposed hybrid machine learning models (p < 0.05). The proposed hybrid machine learning algorithms achieve the goal of low cost and high performance compared to other studies in the literature. The results lead the authors to believe that the proposed system could be used in hospitals as an automatic and objective system for assisting orthopedists in the rapid and effective determination of shoulder implant types before performing revision surgery.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 9
    Investigation of the Electrical Parameters of Ag/P-tlgases Schottky Contacts
    (Elsevier, 2012) Qasrawi, A. F.; Gasanly, N. M.
    p-type TlGaSeS single crystal was used to fabricate a Schottky device. Silver and carbon metals were used as the Ohmic and Schottky contacts, respectively. The device which displayed wide RF band at 13.200 and narrow band at 62.517 kHz with Q value of 1.4 and of 6.3 x 10(4), respectively, is characterized by means of current (I)-voltage (V), capacitance (C)-voltage characteristics as well as capacitance-frequency (f) characteristics. The device series resistance, ideality factor and barrier height are determined from the I-Vcurve as 35.8 M Omega, 1.2 and 0.74 eV, respectively. The apparent acceptor density and the build in voltage of the device increased with increasing ac signal frequency. The high Q value, observed at 62.517 kHz. indicated a much lower rate of energy loss relative to the stored energy of the device. The energy loss (Q(-1)) is much less than 0.001% of the stored value. The device was tested and found to remain at the same mode of resonance for several hours. It never switched or ceased unless it was tuned off. (c) 2012 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 45
    Citation - Scopus: 45
    A Note on "some Results on Multi-Valued Weakly Jungck Mappings in b-metric Space"
    (versita, 2013) Bota, Monica-Felicia; Karapinar, Erdal
    The proofs of Theorems 2.1, 2.2 and 2.3 from [Olatinwo M.O., Some results on multi-valued weakly jungck mappings in b-metric space, Cent. Eur. J. Math., 2008, 6(4), 610-621] base on faulty evaluations. We give here correct but weaker versions of these theorems.