Recep Tayyip Erdoğan Üniversitesi Kurumsal Akademik Arşivi
DSpace@RTEÜ, Recep Tayyip Erdoğan Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve yayınların etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Electronic structure, optical and photocatalytic characteristics of van der Waals Al2SeTe/WSeTe heterostructure
(Taylor and Francis Ltd., 2025) Yelgel, Celal
The escalating global energy crisis and environmental pollution highlight the urgent need for sustainable energy conversion technologies. Photocatalysis, inspired by natural photosynthesis, provides a promising route for solar-to-hydrogen production. Two-dimensional van der Waals (vdW) heterostructures, integrating monolayer semiconductors, offer enhanced photocatalytic efficiency through improved charge separation and tunable interfacial interactions. Using density functional theory, this study investigates the electronic, optical, and photocatalytic properties of Al₂SeTe, WSeTe monolayers, and their vdW heterostructure. Fermi-level alignment induces an internal electric field that facilitates efficient charge transfer while suppressing carrier recombination. The WSeTe/Al₂SeTe heterostructure exhibits thermodynamic stability and a type-I band alignment with an indirect band gap of 0.557 eV, suitable for overall water splitting at neutral pH. Moreover, biaxial strain effectively modulates its optoelectronic characteristics, offering tunability for energy applications. These results provide valuable insights into designing high-performance heterostructures for photocatalytic hydrogen generation.
A multi-perspective exploration of contact behavior in orthotropic layer resting on isotropic half-plane
(Springer Nature, 2025) Terzi, Merve; Öner, Erdal; Uzun Yaylacı, Ecren; Oktay, Mine Gül; Yaylacı, Murat
Contact problems which concern the stress distribution resulting from the interaction between two elastic bodies have long been a focus of research. In the field of solid mechanics, they hold particular importance because loads are generally transmitted to deformable bodies through their points of contact. This study investigates the contact problem of a layered medium containing a homogeneous orthotropic layer and an isotropic half-plane using a multi-method approach. A rigid flat indenter is applied to the orthotropic layer with frictional effects neglected, while the influence of body forces in the orthotropic layer is taken into account. Key contact parameters such as the contact stress under the indenter, the initial separation load, and the point of initial separation are determined as part of the analysis. The study is structured into three main sections. In the first section, the problem is analytically examined based on classical elasticity theory. Within this framework, a singular integral equation governing the contact problem is derived and solved numerically. The second section presents a finite element analysis using ANSYS software to simulate the contact interaction and evaluate the stress distribution. In the third and final section, the problem is addressed through artificial neural network (ANN) techniques, offering a data-driven perspective. Ultimately, the results obtained from the analytical, numerical (FEM), and ANN-based methods are compared, showing excellent agreement across all approaches.
Water scarcity in Asian nations and the path to resilience
(AccScience Publishing, 2025) Anser, Muhammad Khalid; Akhtar, Muhammad Zaheer; Shah, Syed Tahir Hussain; Khan, Muhammad Azhar; Zaman, Khalid
Water, the most essential component for life and ecological balance, is scarce worldwide, particularly in underprivileged countries. This research uses panel data from 39 Asian nations spanning from 1996 to 2022 to examine the impact of water scarcity (WS) on climate change, socioeconomic issues, governance instability, food production, and sustainable groundwater planning. The generalized method of moments estimator results reveal that government effectiveness, regulatory quality, and crop production reduce WS by 17.581%, 55.049%, and 0.171%, respectively. In contrast, agricultural land degradation, renewable energy demand, and climate funding exacerbate WS by 0.001%, 1.551%, and 10.397%, respectively. The study underscores the importance of effective governance and climate financing in securing Asia’s water future.
Prevalence of MASLD and fibrosis risk in Turkish adults with cardiometabolic risk factors: A nationwide multicenter study (DAHUDER MASLD Study)
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Kırık, Ali; Sümbül, Hilmi Erdem; Koca, Nizameddin; Paşalı Kilit, Türkan; Demiral Sezer, Sibel; Beyazal Polat, Hatice; Doğru, Teoman
Introduction: Metabolic dysfunction-associated steatotic liver disease (MASLD) prevalence data in Türkiye is limited. We aimed to determine the nationwide prevalence of MASLD and advanced hepatic fibrosis risk in subjects with cardiometabolic risk factors (CMRF). Despite recent international consensus redefining fatty liver disease terminology, no nationwide MASLD study has been reported in Türkiye. Methods: This cross-sectional study included 14,371 adults with ≥1 CMRF from 44 centers across 31 cities. MASLD was diagnosed using liver ultrasonography plus cardiometabolic criteria. Advanced fibrosis risk was assessed by fibrosis-4 (FIB-4) score (≥1.3 for ≤65 years; ≥2.0 for >65 years). Logistic regression was used to identify independent predictors of high FIB-4. Results: A total of 61.4% of participants were women, the mean age was 51.3 ± 14.4 years, and the mean BMI was 31.4 ± 6.0 kg/m2. MASLD prevalence was 75.7% (n = 10,873), rising with the number of CMRFs (56.5% with one factor vs. 83.4% with all). The prevalence of high FIB-4 scores was 12.0% overall, being lower in MASLD patients than non-MASLD patients (11.2% vs. 14.4%, p < 0.001). FIB-4 scores decreased with increasing BMI (28.1% underweight vs. 8.7% class III obesity). Male sex, T2DM, and hypertension independently predicted high FIB-4 scores, while smoking, higher BMI, and MASLD were inversely associated. Conclusions: Three-quarters of Turkish adults with CMRF have MASLD. Standard FIB-4 thresholds may underestimate fibrosis risk in obese and smoking populations, underscoring the need for adjusted cut-offs or alternative tools. This study is the first to provide nationwide MASLD prevalence data in Türkiye.
Exosomes in HPV-associated cancers: from biomarkers to engineered therapeutics
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Çakır, Muharrem Okan; Selek, Melis; Yılmaz, Betül; Özdoğan, Mustafa; Ashrafi, G. Hossein
Background/Objectives: Human papillomavirus (HPV) is the main causative agent of cervical cancer and contributes to a significant proportion of other anogenital and oropharyngeal malignancies. The need for better biomarkers and therapeutic approaches in HPV-associated cancers has drawn attention to exosomes, small extracellular vesicles known for their stability, biomolecule transport capabilities, and role in cell-to-cell communication. Methods: This review comprehensively evaluates recent literature on the diagnostic, prognostic, and therapeutic applications of small extracellular vesicles, particularly exosomes, in HPV-related cancers. It analyzes findings on exosomal nucleic acids, proteins, and long non-coding RNAs, as well as engineered exosome-based therapies. Results: Exosomal miRNAs (e.g., miR-204-5p, miR-99a-5p, miR-21), proteins (e.g., glycolytic enzymes, HSP90), and lncRNAs (e.g., HOTAIR, DLEU1) have emerged as promising biomarkers for disease detection and monitoring. Exosomal cargo actively participates in HPV-related tumor progression. For example, miRNAs such as miR-21 and miR-146a modulate immune cell polarization and inflammatory signaling, while lncRNAs like HOTAIR promote oncogenic transcriptional programs. Exosomal proteins including HSP90 and ANXA1 facilitate extracellular matrix remodeling and immune evasion, thereby influencing tumor growth and metastasis. In HPV-positive head and neck and cervical cancers, exosomal cargo reflects HPV status, tumor progression, and treatment response. Therapeutic studies demonstrate the utility of exosomes in vaccine delivery, immune modulation, and drug delivery systems, including the use of PROTACs. However, clinical translation faces barriers including isolation protocol standardization, biomarker validation, and scalable production. Conclusions: Exosomes hold great promise for integration into diagnostic and therapeutic workflows for HPV-related cancers. Future research should focus on resolving standardization issues, validating biomarkers in diverse cohorts, and optimizing engineered exosome platforms for targeted therapy.
