WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394

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An Elementary Proof of Lucas's Theorem
(Ramanujan Mathematical Society, 2025) Cinkir, Zubeyir
Lucas's Theorem is about finding the result of a binomial coefficient modulo a prime p efficiently. The result is expressed as a product of binomial coefficients involving the base p expansions of the parameters of the original binomial coefficient. We give an elementary proof of Lucas's Theorem by deriving an analogous Vander-monde identity modulo a prime number.
A Novel Signaling Pathway That Governs Tumor Metastasis: Ceramide Regulates Direct Crosstalk Between TGF-Β and Sonic Hedgehog Signaling
(Federation of American Society for Experimental Biology, 2016) Gencer, Salih; Ogretmen, Besim
Photoluminescent Carbon Dots for Sensitive and Selective Cu2+ Ion Detection
(IOP Publishing Ltd, 2026) Sahin Tiras, Kevser; Karabel Ocal, Sema; Mutlugun, Evren
Green-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.
Performance Boost in QLEDs Using Octanethiol-Capped Core/Shell Quantum Dots
(IOP Publishing Ltd, 2026) Yazici, Ahmet F.; Yuruc, Adnan M.; Kelestemur, Yusuf; Serin, Ramis Berkay; Kacar, Rifat; Ulku, Alper; Mutlugun, Evren
Quantum dots attract significant attention as one of the most promising colloidal nanocrystals with unique optical properties and potential applications for the next generation of display technology. In this paper, we evaluate the performance of CdZnSeS-based alloyed-shell quantum dots (QDs) for electroluminescence devices upon additional shell growth and ligand exchange. This includes core/shell (C/S) and core/shell/shell (C/S/S) QDs, whose latter includes an additional ZnS shell and octanethiol (OT) ligands. We present detailed characterizations of QDs using transmission electron microscopy, XRD, and various spectroscopic techniques and demonstrate their QD light emitting (QLEDs). We find the photoluminescence quantum yield of C/S/S QDs increased from 68.8% to 88.7% compared to C/S QDs whereas the emission linewidth narrows from 22.2 nm to 20.8 nm. QLEDs fabricated with C/S/S QDs exhibit a higher peak external quantum efficiency (EQE) of 4.1% and maximum luminance of 85 000 cd m-2, compared to 2.3% EQE and 67 000 cd m-2 for C/S QLEDs. In this respect, the OT-assisted shell growth significantly improves the optical property of QDs and performance of QLEDs, likely attributed to the enhanced charge balance and increased radiative recombination rate.
Effects of Strain Rate and Post Processing on Mechanical Properties of Additively Manufactured AlSi10mg Alloys
(Walter de Gruyter GmbH, 2026) Karaveli, Kadir Kaan; Bal, Burak
The mechanical properties of AlSi10Mg alloy fabricated by laser powder bed fusion (LPBF) were investigated under different strain rates and post-processing conditions, including shot peening (SP) and stress relief (SR). Tensile tests were performed at quasistatic (0.1 s-1) and dynamic (0.015 s-1) strain rates on as-built and post-processed specimens. The results revealed that SP significantly increased the yield strength by 7.10 %, reaching 249.59 MPa, due to the induced compressive residual stresses. However, while SP slightly improved the ultimate tensile strength (UTS) by 0.25 %, it also reduced elongation at break by 18.06 %, indicating a trade-off between strength and ductility. Conversely, SR improved ductility by reducing internal stresses, leading to an elongation at break increase of 574.01 %, with a slight reduction in yield strength. The combination of SP and SR exhibited a synergistic effect, achieving a balance between strength and ductility. Strain rate sensitivity (SRS) analysis indicated that stress-relieved specimens performed better under dynamic loading conditions. These findings highlight the potential of post-processing techniques in tailoring the mechanical behavior of LPBF-produced AlSi10Mg alloys. The balanced properties achieved through combined treatments make this material particularly suitable for high-performance aerospace and automotive applications, where strength and ductility are critical under varying operational conditions.
A Small Indole Derivative Isolated From Caper (Capparis Ovata) as an Inducer of P53-Mediated Apoptosis in Prostate Cancer: Comprehensive In Vitro and In Silico Studies
(Wiley, 2025) Acar, Ozden Ozgun; Gazioglu, Isil; Oruc, Hatice; Kale, Elif; Senol, Halil; Topcu, Gulacti; Sen, Alaattin
Natural products with stunning chemical diversity have been extensively researched for their anticancer potential for more than fifty years. This study aimed to determine the effect of indole derivative 1H-indole-2-hydroxy-3-carboxylic acid (IHCA), isolated as a novel alkaloid from Capparis ovata, on selected tumor suppressor, apoptotic, and cell cycle regulatory genes, which are known to be important in cancer pathophysiology, on Caco-2 and LNCaP cells in comparison with Taxol. The molecular mechanism of IHCA's anticancer activity is essentially undefined. Different concentrations of IHCA increased the expression levels of apoptosis-related genes, including BCL-2 and TNF-alpha. In addition, the tumor suppressor genes PTEN, P53, and RB were increased in LNCaP and Caco-2 cells. KRAS, an oncogenic gene, was significantly downregulated by IHCA in LNCaP cells. Western blot results showed that the protein expression levels of P53 and PTEN in LNCaP cells were increased when treated with IHCA, whereas CDK4 and TNF-alpha were decreased. Finally, IHCA and doxorubicin significantly increased P53-driven luciferase activity compared to the control. The results strongly suggest that the novel natural compound IHCA has an anticancer effect involving the regulation of the P53 gene and its networks in vitro. The molecular docking and MD simulation analyses reveal that IHCA exhibits superior binding potential to the MDM2 protein compared to Nutlin-3a. MD simulations further confirm that IHCA maintains a more stable and consistent interaction with MDM2, as indicated by lower RMSD values and reduced ligand fluctuation. These results highlight IHCA's potential as a more effective MDM2 inhibitor, suggesting its promise as a lead compound for anticancer drug development.Clinical Trial Registration: Not applicable.
CRISPR/Cas9-Mediated Metabolic Engineering of Endophytic Pseudomonas Loganensis Sp. Nov. for the Production of Nutritionally Valuable Carotenoids
(American Chemical Society, 2026) Arslansoy, Nuriye; Karaman, Melisa Zulal; Fidan, Ozkan
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 beta-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 similar to 5-fold increase in the titers of zeaxanthin (13.4 mg/L), lycopene (9.67 mg/L), and beta-carotene (23.53 mg/L), and a similar to 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.
Multifaceted Effects of the Dielectric Component within Plasmon-Assisted Light-Emitting Structures (Dec, 10.1021/ACS.AOM.5C00628, 2025)
(American Chemical Society, 2025) Kulakovich, Olga; Muravitskaya, Alina; Ramanenka, Andrei; Efimova, Taisia; Krukov, Vitali; Mutlugun, Evren; Gaponenko, Sergey
Deep-Learning Detection of Open-Apex Teeth on Panoramic Radiographs Using YOLO Models
(Springer, 2025) Edik, Merve; Celebi, Fatma; Cukurluoglu, Aykagan
ObjectivesThe use of deep learning in detecting teeth with open apices can prevent the need for additional radiographs for patients. The presented study aims to detect open-apex teeth using You Only Look Once (YOLO)-based deep learning models and compare these models.MethodsA total of 966 panoramic radiographs were included in the study. Open-apex teeth in panoramic radiographs were labeled. During the labeling process, they were divided into 6 classes in the maxilla and mandible, namely incisors, premolars, and molars. AI models YOLOv3, YOLOv4, and YOLOv5 were used. To evaluate the performance of the three detection models, both overall and separately for each class in the test dataset, precision, recall, average precision (mAP), and F1 score were calculated.ResultsYOLOv4 achieved the highest overall performance with a mean average precision (mAP) of 87.84% at IoU (Intersection over Union) 0.5 (mAP@0.5), followed by YOLOv5 with 85.6%, and YOLOv3 with 84.46%. Regarding recall, YOLOv4 also led with 90%, while both YOLOv3 and YOLOv5 reached 89%. Moreover, the F1 score was the highest for YOLOv4 (0.87), followed by YOLOv3 (0.86) and YOLOv5 (0.85).ConclusionsIn this study, YOLOv3, YOLOv4, and YOLOv5 were evaluated for the detection of open-apex teeth, and their mAP, recall, and F1 scores exceeded 84%. Deep learning-based systems can provide faster and more accurate results in the detection of open-apex teeth. This may help reduce the need for additional radiographs from patients and aid dentists by saving time.
Advances in Natural Building and Construction Materials
(MDPI, 2025) Strzalkowski, Pawel; Sousa, Luis; Koken, Ekin
G-C3N4@Fe3O4 Nanomaterial Synthesis for Magnetic Solid-Phase Extraction and Photocatalytic Removal of Basic Blue 3
(Springer Heidelberg, 2025) Kizil, Nebiye; Kayaci, Nilgun; Erbilgin, Duygu Erkmen; Yola, Mehmet Lutfi; Yilmaz, Erkan; Soylak, Mustafa
The present research synthesized a g-C3N4@Fe3O4 hybrid material for efficient magnetic solid-phase extraction (MSPE) and photocatalytic degradation of Basic Blue 3 (BB3) dye from wastewater. Characterization of the synthesized g-C3N4@Fe3O4 was conducted through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The optimization of the method was carried out by examining parameters such as pH, g-C3N4@Fe3O4 amount, sample volume, and adsorption/desorption duration. In addition, analytical performance criteria such as limit of detection (LOD), limit of quantification (LOQ), and relative standard deviation (RSD) of the MSPE method were calculated as 1.29 mu g L-1, 4.28 mu g L-1, and 1.9%, respectively. The method was applied to real samples, including wastewater and textiles, and validated through addition/recovery studies for the magnetic solid-phase extraction procedure. The recoveries were gained between 91 and 100%. The reusability synthesized g-C3N4@Fe3O4 was also evaluated. The recoveries for Basic Blue 3 dye decreased to 81% after the fourth experiment. Furthermore, the photocatalytic performance of the g-C3N4@Fe3O4 hybrid material was evaluated due to its good surface area and strong interaction with Basic Blue 3 dye. The photocatalytic activity of g-C3N4@Fe3O4 hybrid material was calculated as 96.8% for 100 mg in 300 min.
Analysis of Power-Law Fin-Type Problems Using Physics Informed Neural Networks
(Sciendo, 2025) Gocer, M.; Coskun, S. B.; Atay, M. T.
This study aims to model the temperature distribution in a single fin subjected to steady one-dimensional heat conduction with nonlinear thermal behavior. For the modeling and solution of the problem, the Physics-Informed Neural Networks (PINNs) architecture was used. The temperature-dependent heat conduction problem and the nonlinear boundary conditions of this problem were formulated with a differential equation. With the help of the PINN architecture, the loss function was minimized in order to reduce the difference between the true value and the predicted value. During this minimization process, the PINN architecture was forced to be consistent with the physical laws. The results obtained after training the PINN architecture exhibit successful performance in terms of accuracy and reliability when compared with the results in the literature. These findings highlight the potential of PINNs as a powerful alternative to conventional methods for solving complex nonlinear heat conduction problems.
G-S a Prior Biological Knowledge-Based Pattern Detection and Enrichment Framework for Multi-Omics Data Integration
(MDPI, 2025) Unlu Yazici, Miray; Bakir-Gungor, Burcu; Yousef, Malik
The rapid advancements in high-throughput technologies have led to a dramatic increase in diverse -omics data types, enabling comprehensive analyses, especially for complex diseases like cancer. Despite the development of multi-omics approaches, the challenges of scaling integration to massive, heterogeneous -omics datasets suggest that novel computational tools need to be designed. In this study, we propose an approach for integrating microRNA (miRNA) and messenger RNA (mRNA) expression data, incorporating prior biological knowledge (PBK). This approach scores and ranks groups of miRNAs and their associated genes using cross-validation iterations. The proposed method incorporates a Pattern detection (P) component to identify molecular motifs unique to each biological group. The analysis also facilitates the visualization of the groups, facilitating the identification of co-occurring groups and their characteristic features across iterations. Furthermore, the groups are scored using an over-representation analysis through a new Enrichment (E) component in each iteration. The clusters of the groups based on the Enrichment Scores (ESs) are visualized in a heatmap to obtain novel insights into the collective behavior and dependencies of the groups, aiming to understand the molecular mechanisms of complex diseases. The developed G-S-M-E tool not only provides performance metrics and biological scores at the group level but also offers comprehensive insights into intricate multi-omics interactions. In summary, our study emphasizes the importance of mathematical and data science methodologies in elucidating intricate multi-omics integration, yielding a formalized approach that deepens our comprehension of complex diseases.
Assessment of the Quality of Tuffs in Central Anatolia, Turkey: A Quantitative Classification Approach
(Acad Sci Czech Republic Inst Rock Structure & Mechanics, 2025) Koken, Ekin; Ince, Ismail
The growing global demand for dimension stones necessitates efficient and accurate evaluation methods to ensure their optimal use in various industries. To assess their suitability for various dimension stone applications, this study investigates tuffs from Central Anatolia, Turkey. For this purpose, the fundamental physical and mechanical properties of the tuffs were determined in laboratory studies, and a detailed durability assessment was conducted for each rock type. The analysis results indicate that most of the examined rocks are of low quality and more suitable for non-load-bearing applications. Based on the collected data, fuzzy clustering techniques were applied to develop a new classification system, categorising the tuffs into four classes (Class A-D) according to their potential applications. Additionally, a user-friendly MATLAB-based software tool was also developed to facilitate the implementation of the proposed classification system.
Colloidal Photodetectors Based on Engineered Multishelled InP Based Quantum Dots
(IOP Publishing Ltd, 2026) Akrema; Erol, Erdinc; Savas, Muzeyyen; Yazici, Ahmet Faruk; Erdem, Talha; Mutlugun, Evren
In 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 x 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.
Shooting a Water Slug Into an Air Column with and without Vent
(Amer Soc Mechanical Engineers, 2025) Bozkus, Zafer; Dincer, Ali Ersin; Tijsseling, Arris S.; van de Ven, Fons
Compressed air is used to shoot a single water slug into an upward sloping pipe with elbow and orifice at its upper end. The experiment concerns a 12 m long pipe of 0.1 m diameter connected to a 0.5 m3 air vessel. The 10 to 50 kg heavy slugs are initially at rest in the lower part of the system. Because the upper end is closed by a flange with orifice, the water slug is expected not to hit the upstream elbow. It causes - like a piston - a fast compression of the air column ahead of it. Sometimes the slug bounces back and forth, which results in a pressure oscillation of serious amplitude. Numerical simulations based on an elementary mathematical model are normally used to interpret the pressure measurements, not all of which are fully understood. Lessons learned are summarised, and suggestions for improved experiments and enhanced simulations are given. The research is of importance, for example, for steam lines where liquid condensates may collect in lower parts after power failure. Start-up of the system will then lead to rapid slug acceleration and potentially damaging impact on elbows, orifices, and machinery.
Does Your Love Lift Me Higher? A Direct Replication of the Energising Role of Secure Relationships
(John Wiley & Sons Ltd, 2025) Lagap, Adar Cem; Harma, Mehmet
Previous work has revealed that priming people with significant others increases feelings of security and energy, and in turn, boosts exploration motivations. In this preregistered study, we directly replicated Luke et al.'s (2012) Study 2 (N = 281). We found similar results as the replicated study regarding increased security feelings and exploration motivations on the self-report measures after the priming. However, we did not find any support for the increased energy feelings after the attachment security priming. In addition, contrary to Luke et al.'s (2012) results, energy feelings did not mediate the relationship between security priming and exploration motivations. A discussion of null findings, along with the limitations of self-reports and potential misinterpretation of the mediational analyses, follows. We also discuss possible future implications of the current findings.
Measuring Disaster Resilience in MENA Countries and Its Impact on Disaster Losses
(Nature Portfolio, 2025) Demir, Abdullah; Dincer, Ali Ersin; Dincer, Nazire Nergiz
Disaster resilience is a protective feature aimed at reducing the effects of natural disaster events and losses resulting from these events. This study develops a Disaster Resilience Index (DRI) for MENA countries to assess resilience across ten dimensions, including economic, social, institutional, infrastructural, and environmental factors. Unlike most prior studies, which focus on individual countries or use narrower sets of indicators, this study provides a multi-country, region-specific framework tailored to MENA's socio-economic and environmental heterogeneity. The index integrates geospatial data on disaster risk from geographic information systems (GIS) and a natural hazard risk dimension. Validation using disaster-related fatalities, supported by a dual PCA-based sensitivity analysis, confirms the robustness of the DRI and reveals that countries with stronger governance, higher human capital, and robust infrastructure tend to exhibit greater resilience, while fragile states and resource-dependent economies are more vulnerable. Notably, the DRI calculated using both dimension-specific and all-indicator PCA produces closely aligned values, indicating the choice of conducting PCA at the dimension level does not significantly alter the overall assessment of disaster resilience. These insights provide a foundation for targeted disaster risk reduction strategies and highlight areas where international cooperation and policy interventions can strengthen resilience in the region.
Ultra-Durable Information-Encoded Anti-Counterfeiting Self-Assembled Nanocrystal Labels
(Wiley-VCH Verlag GmbH, 2025) Haddadifam, Taha; Shabani, Farzan; Kalay, Mustafa; Khaligh, Aisan; Mutlugun, Evren; Onses, Mustafa Serdar; Demir, Hilmi Volkan
Forgery, a serious universal problem, is causing huge economic losses every year. Against forgery, information-encoded labelling systems have attracted significant attention for a diverse range of anti-counterfeiting applications. Here, cost-effective and ultra-durable nanocrystal-based labels are proposed and demonstrated in which information can be encoded as physically unclonable functions (PUFs) of hardware-oriented security systems. The fabrication method of the PUFs is based on the self-assembly of colloidal quantum wells (CQWs) and generation of unclonable features within their pattern at a liquid-liquid interface. These CQW PUFs are analyzed with well-known statistical tests, which show a uniqueness level of 0.5060 +/- 0.0323 and prove their randomness. In addition, a feature-matching algorithm is used to authenticate these information-encoded CQW PUFs. For the safety of the semiconductor chips, a CQW PUF is attached to the surface of the chip to protect against hardware cyber-attacks. Eventually, fabricated labels are examined against high temperatures and moisture environments. The fabricated CQW label is durable for a period of 150 days it is tested, demonstrating ultra-high stability of the label. High stability and durability, cost-effectiveness, and high encoding capacity make these proposed nanocrystal labels extremely attractive for large-scale commercialization.
Neuroinflammatory Human Brain Organoids Enable Comprehensive Drug Screening Studies: Fingolimod and Its Analogues in Focus
(Bentham Science Publishing Ltd, 2026) Acar, Busra; Pepe, Nihan Aktas; Zivkovic, Aleksandra; Stark, Holger; Sen, Alaattin
Introduction The absence of physiologically relevant models for neuroinflammatory brain disorders, such as multiple sclerosis (MS), highlights the need for improved drug screening platforms. To bridge this gap, this study aimed to develop a human brain organoid (hBO) model incorporating essential neural cell types, including astrocytes, microglia, and oligodendrocytes.Methods hBOs were generated from H9 stem cells, and neuroinflammatory characteristics were elicited by lipopolysaccharide (LPS). The expression of specific neuronal and inflammatory markers was assessed through qRT-PCR, immunofluorescence staining (IFS), and ELISA.Results IFS of mature hBOs with anti-SOX2, anti-SATB2, anti-MAPT, anti-GFAP, anti-MBP, and anti-IBA1 antibodies and images collected with the confocal microscope confirmed the differentiation of H9 cells into cortical neurons, astrocytes, microglia, and oligodendrocyte cell types. Elevated GFAP, IBA1, NF-kappa B, and IL-6 levels, along with reduced CNPase expression with LPS treatment, were considered reflective of MS-like pathology and were used to test fingolimod and its derivatives. Fingolimod and all its derivatives, specifically ST-1505, decreased MAPT (2.1-fold in ELISA, 1.7-fold in IFS), GFAP (1.8-fold in IFS), TNF alpha (5.4-fold in qRT-PCR), and FABP (1.5-fold in ELISA) levels, and increased IL-10 (11-fold in qRT-PCR) and MBP (2.9-fold in IFS) levels.Discussion The present data collectively showed LPS to evoke neuroinflammation in the hBO model, while fingolimod and its derivatives, particularly ST-1505, exhibited significant anti-inflammatory and neuroprotective properties by counteracting these evoked changes in the hBO model.Conclusion The findings supported the applicability of brain organoids as a model system for drug screening studies for neuroinflammatory brain diseases.

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