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
Global sensitivity analysis of Rayleigh wave propagation in functionally graded skin tissue: A fractional three-phase lag thermo-viscoelastic model
(Elsevier, 2026) Khan, Maaz Ali; Abualnaja, Khadijah M.; Jahangir, Adnan; Mahmoud, Emad E.; Riaz, Usman; Yaylacı, Murat
The paper develops a complete fractional three-phase lag thermo-viscoelastic model in order to investigate Rayleigh wave propagation in the functionally graded human skin tissue. The proposed framework combines nonlocal elasticity, fractional memory effects, and depth-dependent material gradation-a key lacuna in the integration of multi-physics into biological wave modeling. Furthermore, it conducts the GSA using the variance-based Sobol method to quantify the influence of primary parameters, namely elastic nonlocality (ϵ1), thermal nonlocality ϵ2, fractional order (α), gradation parameter α*, phase lags τq,τT,τv, and hydrostatic stress (P) on phase velocity, attenuation, penetration depth, and specific heat loss. All phase velocities are normalized by a reference speed c0=10m/s (typical for skin) to present dimensionless results; the corresponding physical values lie in the range 100−1000m/s, consistent with elastography measurements. Results have demonstrated that wave characteristics are mainly controlled by thermal nonlocality ϵ2 with respect to heat loss, the fractional order (α) for penetration depth, while elastic nonlocality ϵ1 for phase velocity, and attenuation is the result of very complex synergistic interactions of all parameters. Herein, GSA provides a sound hierarchy for model simplification and parameter prioritization, providing needed insight into optimizing diagnostic elastography and thermal therapies in clinical applications.
Protective effects of medicago sativa extract on oxidative stress and apoptosis in a dmba-induced experimental breast carcinogenesis model
(SAGE Publications Inc., 2026) Demir, Baran; Kafadar, Mehmet Tolga; Yıldızhan, Eda; Akkuş, Murat
Background: Breast cancer is a leading cause of cancer-related morbidity and mortality worldwide, and oxidative stress plays a critical role in early mammary carcinogenesis. Medicago sativa has been reported to possess antioxidant properties; however, its effects on early oxidative stress–apoptosis interplay in breast tissue remain unclear. Methods: Twenty-eight female Wistar albino rats were randomly allocated into four groups: control, DMBA, Medicago sativa, and DMBA + Medicago sativa (n = 7 each). Breast carcinogenesis was initiated by a single intraperitoneal dose of 7,12-dimethylbenz[a]anthracene (DMBA; 80 mg/kg). Medicago sativa extract was administered orally at 250 mg/kg/day for 10 weeks. Serum malondialdehyde (MDA), total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were measured. Mammary tissues were evaluated histopathologically and immunohistochemically for Bax and Bcl-2 expression. Results: DMBA administration significantly increased serum MDA, TOS, and OSI levels compared with the control group (p < 0.05). Medicago sativa treatment significantly reduced MDA, TOS, and OSI levels in the DMBA + Medicago sativa group (p < 0.05). No statistically significant difference in TAS levels was observed between the DMBA and DMBA + Medicago sativa groups. Histopathological analyses revealed moderate fibrosis, inflammatory infiltration, degenerative epithelial changes, and ductal hyperplasia in the DMBA group, whereas these alterations were attenuated following Medicago sativa treatment. The immunohistochemical evaluation demonstrated that, compared with the DMBA group, Bax expression with pro-apoptotic function increased, while Bcl-2 expression with anti-apoptotic function decreased in the DMBA + Medicago sativa group. Conclusions: Medicago sativa mitigates DMBA-induced early mammary tissue damage by reducing oxidative stress and modulating Bax/Bcl-2–mediated apoptotic signaling prior to overt tumor formation, highlighting its mechanistic relevance in targeting early stages of breast carcinogenesis.
The impact of digital design on Façade performance: A literature review
(Yildiz Technical University, 2026) Akkan Çavdar, Ayça; Vural, Nilhan
Advances in technology and interdisciplinary collaborations have increased design efficiency through new materials and construction systems, and have supported innovations in the field of architecture. However, despite these developments, performance evaluation before construction remains crucial. Therefore, digital design methods and performance analysis software have become fundamental tools in the optimization process. This study examines the role of digital design in improving facade performance within the context of sustainable archi-tecture. In this context, 96 studies obtained from the Web of Science (WoS) database were ex-amined. Trends in the research were evaluated using bibliometric methods and content analysis applied via VOSviewer. The findings show that the majority of studies focus on daylight, energy efficiency, and solar radiation. In contrast, topics such as ventilation, indoor air quality, and acoustics were addressed to a more limited extent. In recent years, digital twin applications and artificial intelligence-supported facade optimization have gained more prominence. Simulation methods are dominant in the studies examined (65.6%). The most commonly used tools are Rhinoceros and Grasshopper. Only 58.3% of the studies received financial support. China stands out in terms of both the number of articles and the number of supported studies. This study presents a systematic classification for facade performance criteria and digital tools. It also draws attention to research gaps, particularly in the areas of ventilation and cooling performance. By highlighting these insufficiently addressed areas, the research differs from previous studies and offers a roadmap for future research towards developing digital facade design with a more comprehensive and multidisciplinary approach.
Various impact of polishing system on roughness, microhardness, phase transformation, flexural strength of monolithic zirconia
(Ataturk Universitesi, 2026) Akyıldız, Gülşah; Yeşil, Zeynep
Objective: The aim of this study was to evaluate the effect of different surface polishing systems and autoclave aging process on the surface properties, phase transformation and flexural strength of monolithic zirconia. Methods: Forty eight Ø15×1.2 ±0.01-mm disks of one monolithic zirconia materials (Prettau, Zirkonzahn) were prepared glazed, and assigned to 3 groups: A control group with no additional treatment after glaze; and 2 groups in which the glaze layer was removed and the surfaces polished using 2 different polishing systems (OptraFine and Meisinger). After the polishing, each group was divided into two and one of these was aged in an autoclave. The surface roughness of the samples was analyzed using a profilometer device, the surface microhardness was evaluated using the Vickers microhardness test. Both atomic force microscopy and scanning electron microscopy were used to image the surface properties. Phase transformation was analyzed using X-ray diffraction. Finally, the flexural strengths were evaluated. Results: The effects of surface polishing applied on monolithic zirconia specimens were found to be statistically significant. The effect of autoclave aging on the phase transformation was significant, but the effect on surface roughness, microhardness, and flexural strength was not statistically significant. Conclusion: It was determined that the surface polishing systems applied to the monolithic zirconia specimens affected the surface properties, phase transformation, and flexural strength. The autoclave aging process did not affect the surface properties and flexural strength but affected the phase transformation.
Microalgae-mediated synthesis and characterization of metal oxide nanoparticles for potential enhancement of tomato plant growth and their effects on methylene blue dye degradation
(Wiley, 2026) Mujtaba, Anab; Naseem, Marfaa; Abid, Rameesha; Ali, Muhammad Ishtiaq; Asghar, Rabia; Tutar, Yusuf; Badalov, Bakhtiyar
Agricultural productivity and environmental quality are increasingly threatened by the limitations and hazards associated with conventional chemical inputs. To address this, the present study explores the biosynthesis of metal oxide nanoparticles using microalgal extracts of Tetradesmus nygardii and evaluates their potential as biofertilizers, antifungal agents, and photocatalytic materials. Synthesized nanoparticles were structurally and optically characterized by UV–Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), which confirmed phase-pure crystalline formation at nanoscale dimensions. AgONPs exhibited ultra-small crystallites (1.23–2.70 nm), while CuONPs and NiONPs ranged from 11.2–13.9 nm and 11.8–18.9 nm, respectively. When applied to tomato (Solanum lycopersicum) plants, AgONPs produced a 166% increase in chlorophyll content (37.8 μmol m−2) and a shoot fresh weight of 4.5 g, while reducing disease prevalence from 38.46% to 3.03%. A combined nanoparticle treatment further reduced disease incidence to 6.25% and extended shoot length to 55 cm, indicating synergistic growth-promoting effects. In antifungal assays against Rhizopus spp., complete inhibition was recorded at 200 μg/mL across all tested nanoparticles, with AgONPs and ZnONPs showing superior dose-dependent activity. For photocatalytic performance, AgONPs achieved a methylene blue degradation efficiency of 98.27% under sunlight at a rate of 30.84%/h. These results highlight microalgae-derived AgONPs as a multifunctional and scalable solution for enhancing crop health, controlling phytopathogens and degrading textile dye pollutants, offering a sustainable alternative to synthetic agrochemicals and chemical-based remediation approaches.
