WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Citation - WoS: 1Citation - Scopus: 1Photoluminescent Carbon Dots for Sensitive and Selective Cu2+ Ion Detection(Institute of Physics, 2026-01-07) Sahin-Tiras, K.; Karabel Ocal, S.; Mutlugün, E.; Sahin Tiras, KevserGreen-emitting carbon dots (CDs) were synthesized via a solvent-free, vacuum-assisted method using citric acid and urea. The CDs exhibited strong photoluminescence and served as selective, sensitive probes for Cu2+ detection in water, with a detection limit of 26 nM. Among the tested metal ions, Cu2+ induced the most significant PL quenching. Time-resolved photoluminescence measurements of the CDs in the presence of Cu2+ ions revealed a minimal change in lifetime, despite a significant decrease in PL intensity, along with unchanged UV-vis absorption, indicating a mixed quenching mechanism. The sensor’s applicability was confirmed in raisin extract and tea infusion, showing notable PL suppression. With their simplicity, selectivity, and sensitivity, these CDs offer promising potential as nanosensors for detecting Cu2+ in environmental and real-world analytical settings. © 2026 The Author(s). Published by IOP Publishing Ltd.Article CRISPR/Cas9-mediated Metabolic Engineering of Endophytic Pseudomonas Loganensis Sp. Nov. for the Production of Nutritionally Valuable Carotenoids(American Chemical Society, 2026-01-02) Arslansoy, N.; Karaman, M.Z.; Fidan, O.Carotenoids with significant nutritional and antioxidant properties have been widely utilized in the food, feed, pharmaceutical, and cosmetic industries. They improve the nutritional value of foodstuffs and have been used as natural food colorants. However, their current supply chain is mainly dependent on extraction from plants and chemical synthesis, both of which have bottlenecks, including environmental concerns, toxicity, and allergenicity. To address global demand for sustainable and environmentally friendly production of nutrients, we engineered the endophytic Pseudomonas loganensis sp. nov. as a niche microbial chassis for nutritionally valuable carotenoid production. Using CRISPR-Cas9, we knocked out key carotenogenic genes to construct strains capable of producing zeaxanthin, lycopene, and β-carotene. Additionally, an overexpression plasmid was introduced to produce astaxanthin. HPLC analysis confirmed the successful production of four target carotenoids. The culture conditions and media compositions were optimized using response surface methodology, resulting in a ∼5-fold increase in the titers of zeaxanthin (13.4 mg/L), lycopene (9.67 mg/L), and β-carotene (23.53 mg/L), and a ∼12-fold increase in astaxanthin titer (1 mg/L) compared to LB medium without optimization. Our results indicate the potential of endophytic bacteria as a microbial chassis for carotenoid bioproduction, underscoring the potential of synthetic biology to contribute to global efforts toward nutritional security and sustainable food systems. © 2026 The Authors. Published by American Chemical SocietyArticle Colloidal Photodetectors Based on Engineered Multishelled InP Based Quantum Dots(Institute of Physics, 2026-01-08) Akrema; Erol, E.; Savaş, M.; Yazici, A.; Erdem, T.; Mutlugün, E.; Faruk Yazıcı, AhmetIn this work, we present a straightforward and cost-effective approach to synthesize multi-shell InP/ZnSe/ZnSeS/ZnS quantum dots (QDs) that show promising potential for use in photodetectors. By carefully layering ZnSe, ZnSeS, and ZnS shells around an InP core, we were able to enhance the stability and optical performance of the QDs, achieving a narrow emission peak of 45 nm and a high photoluminescence quantum yield of 55%. These QDs were then integrated into simple photodetector devices, which possessed impressive sensitivity and detection capabilities. Specifically, our devices achieved a peak responsivity of 0.54 A W−1 and a detectivity of 2.22 × 1011 Jones at 400 nm with a 5 V bias. This study highlights the potential of InP-based QDs as a safer and more sustainable alternative to traditional QDs that contain toxic heavy metals, offering a viable path forward for developing high-performance optoelectronic devices. Our findings suggest that these InP/ZnSe/ZnSeS/ZnS QDs could be a key material for the next generation of high-performance optoelectronic devices, especially in applications that require highly sensitive and stable photodetectors. © 2026 The Author(s). Published by IOP Publishing Ltd.Conference Object Clean Energy Production and Decarbonization of Energy Sector With Floating Photovoltaic Systems(Institute of Physics, 2025-11-01) Bajc, T.; Ozgun, F.; Koca, K.; Karipoğlu, F.Floating photovoltaic systems (FPVS) offer several advantages over traditional land-based PV systems, which has contributed to a growing global interest in their deployment. Since the energy yields are strongly dependent on location and tilt angle of FPVS, this research focuses on the clean energy production and decarbonization potential of FPVS in Serbia and Türkiye for different water bodies, such are natural and artificial lakes and dams. The research is performed for the most appropriate lakes and dams, having in mind importance of the location, energy yields potential, distance from the electricity grid and main roads, environmental impact, water depth and land type quality. Tilt angles are analyzed in a range from 5 to 40°, and the optimal angle is depicted for selected locations. The highest energy yields for Türkiye were obtained for 30° tilt angle, while for Serbia it was 36°. The results showed that possible clean energy production in both countries reaches 15345 kWh of energy in total, while the yearly carbon emissions reduction for all selected locations goes up to 10.76 tCO<inf>2</inf>/year in total. Since the legal framework for the application of FPVS is not established yet in observed countries, these results contribute to the future development of legislation in the field of FPVS and encourage the stakeholders to invest in clean energy production. © Published under licence by IOP Publishing Ltd.Conference Object Modular Floating Energy Islands With Green Hydrogen Integration: Design of a Small-Scale P2x Scheme(Institute of Physics, 2025-11-01) Akpolat, A.N.; Cundeva, S.; Todorovic, J.; Rexhepi, V.; Okhay, O.; Bakon, T.; Borg, R.P.The climate crisis and rising carbon emissions make the integration of renewable energy systems into electricity grids worldwide inevitable. In this context, modular floating energy islands (MFEI) provide innovative solutions for hybrid systems with high renewable energy penetration. This study explores the simultaneous use of various renewable resources, such as solar, wind, tidal, and wave energy, through small-scale MFEI structures that can be situated in seas and lakes. Thanks to their modular design, these systems offer benefits like scalability, portability, and ease of maintenance, allowing for flexible and adaptive developments in the energy infrastructure. As highlighted in recent literature (e.g., the North Sea Wind Power Hub and EU H2Ocean projects), offshore structures for green hydrogen production support energy storage and carbon-free fuel conversion within the Power-to-X (P2X) framework. This study evaluates the potential of photovoltaic (PV)-supported hydrogen production in MFEI structures through numerical analyses. The results emphasize the strategic role of these structures in enhancing energy security, coastal protection, and reducing carbon emissions by producing significant amounts of hydrogen. This hydrogen can be used for various purposes, including re-electrification, industrial applications, heating, and agriculture. Future research should focus on real-time data optimization, AI-supported system management, and integrated hydrogen consumption scenarios. © Published under licence by IOP Publishing Ltd.Article Citation - WoS: 1Citation - Scopus: 1An Ultra-Low Fabric Capacitive Glove for Real-Time Motion Tracking and Human–computer Interaction(Institute of Physics, 2025-11-04) Başıbüyük, Y.; Mutluç, M.N.; Şavur, Ö.; İçöz, K.This study presents the development of a wearable glove system that integrates ultra-low-cost, fabric-based capacitive sensors for motion detection and human–computer interaction. The system combines touch and bend sensors fabricated from commercially available silver-coated fabric and silicone acrylic tape, enabling real-time tracking of finger movements via measurable capacitance changes. The glove translates physical gestures into digital commands, facilitating intuitive control in virtual environments. Experimental evaluation demonstrated stable operation across a wide pressure range (10–200 g, equivalent to 1.25–25 kPa), with an unnormalized sensitivity of ∼0.00504 pF g−1 (∼0.0040 pF kPa−1), corresponding to a normalized sensitivity of ∼0.0067 kPa−1 when referenced to the baseline capacitance (C<inf>0</inf> ≈ 6 pF). The device exhibited high repeatability over 4000 loading cycles, and minimal signal variation (coefficient of variation, CV < 0.005). Integration with a Unity-based interface enabled low-latency gesture tracking in real time. Each sensor was fabricated for less than $0.05 using simple, scalable methods, without nanomaterials or cleanroom processing. Owing to its affordability, fabrication simplicity, and mechanical robustness, the proposed glove system provides a practical and scalable platform for wearable motion tracking, with strong potential in rehabilitation, assistive technologies, and interactive systems. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.Article Citation - WoS: 7Citation - Scopus: 8Using Students' Performance to Improve Ontologies for Intelligent E-Learning System(Edam, 2015) Icoz, Kutay; Sanalan, Vehbi A.; Cakar, Mehmet Akif; Ozdemir, Esra Benli; Kaya, SukruOntologies have often been recommended for E-learning systems, but few efforts have successfully incorporated student data to represent knowledge conceptualizations. Defining key concepts and their relations between each other establishes the backbone of our E-learning system. The system guides an individual student through his/her course by evaluating their progress and suggesting instructional material to review based upon their answers. Three main tasks are performed within this framework: building ontologies for the course, measuring a student's understanding level for the concepts, and making personal suggestions to create an individualized learning environment. This paper presents: the integration of ontologies, assisted with student data, together with an intelligent Recommendation Module for the development of an E-learning system; the comparison and correction adaption of ontology from students' mind maps; and the assessment of students' actual weaknesses in comparison to what Recommendation Module suggests. The sample of 127 students, five classrooms, was conveniently selected among seventh grade students of a demographically average school in a major city in Turkey. The students' achievement was assessed and the scores for different questions were investigated for associations with concepts made in the students' minds. The results provided significant correlations among scores, and a fit model for the concepts represented by questions. The student suggested model slightly differed from the ontology map from the experts. Based on the data-supported model, the Recommendation Module more accurately determined the students' learning deficiencies and suggested concepts to be reviewed.Conference Object Turkish English Teachers' Professional Teacher Self as One of the Possible Selves(Elsevier Science Bv, 2016-10) Demirezen, Mehmet; Ozonder, OzgulThis study reports the results of a study exploring Turkish English teachers' professional self in relation to teacher education. The study also examines the relationship between the participants' educational background, teaching experience and their professional self The study was carried out in Ankara, Turkey. The participants of the study were English language instructors of Hacettepe University, School of Foreign Languages. A total of 43 English instructors (females: 36 and males: 7) voluntarily participated in the study, responding to a questionnaire composed of 40 items regarding teacher professional self. The results of the Professional Self Questionnaire revealed that the rate of Turkish English teachers' professional self was very high (81%, M=4.09). Also, there was a significant difference in participants' professional self depending on their educational background. The results indicated that the participants' professional self did not differ significantly in relation to their teaching experience. (C) 2016 Published by Elsevier Ltd.Book Part Citation - WoS: 1Turkey(Routledge, 2017) Yoney, Nilufer Baturayoglu; Salman, Yildiz; Polat, Ebru OmayConference Object Citation - Scopus: 1Three-Dimensional Imaging in Degraded Visual Field(IOP Publishing Ltd, 2016-04) Oran, A.; Ozharar, S.; Ozdur, I.Imaging at degraded visual environments is one of the biggest challenges in today's imaging technologies. Especially military and commercial rotary wing aviation is suffering from impaired visual field in sandy, dusty, marine and snowy environments. For example during landing the rotor churns up the particles and creates dense clouds of highly scattering medium, which limits the vision of the pilot and may result in an uncontrolled landing. The vision in such environments is limited because of the high ratio of scattered photons over the ballistic photons which have the image information. We propose to use optical spatial filtering (OSF) method in order to eliminate the scattered photons and only collect the ballistic photons at the receiver. OSF is widely used in microscopy, to the best of our knowledge this will be the first application of OSF for macroscopic imaging. Our experimental results show that most of the scattered photons are eliminated using the spatial filtering in a highly scattering impaired visual field. The results are compared with a standard broad area photo detector which shows the effectiveness of spatial filtering.