İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
DSpace@İSTÜN, Üniversite mensupları 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 telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
An integrated machine learning and optimization approach for enhanced strength prediction in riveted joints
(Obuda University, 2026) Tanrıver, Kürşat; Ay, Mustafa
In this study, experimental tests, finite element analysis, and machine learning techniques were integrated to predict the maximum shear stress of riveted joints. First, ten tensile tests were conducted, yielding an average stress of 76.0383 MPa on the plates, and the regression analysis of the stress–strain data demonstrated a 95-99% level of agreement. A finite element analysis performed in Ansys under conditions similar to the experiments, produced a result of 78.875 MPa, which falls within an error margin consistent with the literature. Subsequently, a dataset of 20 samples containing various rivet diameters, plate thicknesses, hole coordinates and tensile loads was generated and used, to train a Regression Decision Tree model in MATLAB. For a new design case, the model predicted 7.480 MPa instead of 7.291 MPa, corresponding to an error of approximately 2.50%. When the dataset was expanded to 50 samples, this deviation decreased to 0.82%, indicating a significant improvement in accuracy. Overall, the results demonstrate that the machine learning model rapidly improves, as additional data become available and can provide reliable, fast predictions, including the effects of bending moments, offering a promising approach that may reduce the need for extensive experimental and numerical analyses.
Ketamine induces apoptosis and inhibits proliferation in HT-29 colorectal cancer cells
(MDPI Publishing, 2026) Korkmaz, Irmak Fatoş; Elgün, Tuğba; Aktaş, Çiğdem; Gündeğer, Ersin; Gök Yurttaş, Asiye
Background: Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide and remains a major health concern due to its high recurrence and mortality rates. Recent studies suggest that anesthetic agents, including ketamine, may have direct effects on cancer cell viability and apoptosis. Objective: This study aimed to investigate the in vitro effects of ketamine on the HT-29 human colorectal adenocarcinoma cell line, focusing on its cytotoxic and pro-apoptotic potential. Material and Methods: HT-29 cells were treated with ketamine for 24 h. Cell viability was evaluated using the MTT assay. Apoptosis rates were determined by flow cytometry with Annexin V-FITC/7-AAD staining. Furthermore, quantitative PCR (qPCR) was performed to assess the expression levels of key genes associated with proliferation and apoptosis. GeneQuery™ Human Basal Cell Carcinoma qPCR Array Kit (GQH-BCC-GK015-C) was used for qPCR analysıs. Molecular docking simulations were performed to investigate the potential molecular interactions between ketamine and three target proteins: the N-methyl-D-aspartate (NMDA) receptor, epidermal growth factor receptor (EGFR), and casein kinase 1 delta (CSNK1D). To ensure robustness of predictions, two independent docking methods were employed. Results: Ketamine significantly reduced cell viability in a dose-dependent manner, with an IC50 value of approximately 1.05 µM. Flow cytometry analysis demonstrated a marked increase in early apoptosis (23.9%) in treated cells. These findings suggest that ketamine exhibits potential anti-proliferative and pro-apoptotic effects on HT-29 colorectal cancer cells. Conclusions: These findings suggest that ketamine exhibits potential anti-proliferative and pro-apoptotic effects on HT-29 colorectal cancer cells in vitro. Further studies are warranted to elucidate the underlying molecular mechanisms and potential clinical implications.
Sustainable synthesis of ZnO nanoparticles from melon (cucumis melo l.) by-products: RSM optimization, structural characterization, antioxidant activity, and photocatalytic performance
(Wiley, 2026) Bozkurt, Rabia Nur; Kaba, İbrahim; Kahraman, Yusuf Sezai; Altınkeser, Tuğçe
This study explores the eco-friendly synthesis of zinc oxide nanoparticles (ZnO-NPs) using polyphenol-rich extracts from melon (Cucumis melo L.) peel and seeds as naturalreducing and stabilizing agents. Optimization via response surface methodology (RSM) determined the ideal synthesis conditions at a 0.078 mol/L metal concentration, 14.73 mL extract, and pH 10.77. Characterization through XRD confirmed a hexagonal wurtzite crystal structure with an average size of 21.7 nm, while SEM and TEM imaging revealed predominantly spherical morphologies. UV–visible DRS analysis showed a 368 nm absorption edge with a calculated band gap of 3.21 eV. DLS measurements indicated a hydrodynamic diameter of 135.6 nm with a PDI of 0.206 and a zeta potential of −20.5 mV, confirming good colloidal stability. The resulting NPs exhibited strong antioxidant activity (IC50 = 40.7 µg/mL) and acted as effective heterogeneous photocatalysts for the degradation of organic dyes. Specifically, ZnO-NPs enabled the photodegradation of methyl orange (MO) and methylene blue (MB), achieving 63.56% degradation for 5 mg L−1 MO. These findings demonstrate that melon-waste-derived ZnO-NPs are sustainable and promising candidates for wastewater treatment and environmental remediation.
The impact of home-based telerehabilitation pranayama on sleep quality and wellbeing in mild to moderate obstructive sleep apnea syndrome. A randomized controlled trial
(BioMed Central, 2026) Kaçar Akkoç, Zeynep; Demir, Rengin; Mustafaoğlu, Rüstem; Önder, Ömer Önder; Naci, Baha; Atahan, Ersan
Background Obstructive sleep apnea syndrome (OSAS) is a common disorder that causes repeated airway obstruction, disrupted breathing, and fragmented sleep. This study aimed to investigate the effects of Pranayama on sleep quality, daytime sleepiness, quality of life, fatigue, depression, and anxiety in patients with OSAS. Methods This study was designed as an open-label, prospective, randomized controlled trial. OSAS patients meeting the inclusion criteria were randomly assigned to either an Intervention group or a Control group. Pranayama training was applied to the Intervention group for 8 weeks, 7 days a week, and 3 times a day for 15 min. In addition, a single 15-minute session, 3 days a week, was conducted online under the supervision of a physiotherapist. The control group did not receive any intervention. Primary outcome was sleep quality (Pittsburgh Sleep Quality Index, PSQI). Secondary outcomes included daytime sleepiness (Epworth Sleepiness Scale, ESS), Fatigue Severity Scale (FSS), Functional Outcomes of Sleep Questionnaire (FOSQ), Nottingham Health Profile (NHP), and Hospital Anxiety and Depression Scale (HADS). All outcome measures were assessed at baseline and reassessed after the 8-week intervention period. Results Thirty-eight OSAS patients meeting the inclusion criteria were randomly assigned to either an Intervention group (n = 19) or a Control group (n = 19). Four participants (two in each group) were lost to follow-up, leaving the data of 34 participants (17 per group) available for inclusion in the final analysis. In the intervention group, PSQI scores decreased from 9.12 ± 4.71 to 6.88 ± 4.45 (p < 0.001), whereas no improvement was observed in the control group. Regarding the primary outcome, the reduction in PSQI scores was significantly greater in the intervention group than in the control group (p < 0.001). The ESS scores also decreased significantly in the intervention group, from 9.41 ± 6.15 to 7.41 ± 6.18 (p = 0.006, with a significant between-group difference (p < 0.001). Fatigue severity decreased in the intervention group (FSS change: 0.53 ± 0.70; p = 0.006), with a significant between-group difference (p = 0.037). The FOSQ score improved markedly, with significant gains in FOSQ total score (− 0.38 ± 0.25 vs. 0.14 ± 0.22 in controls; p < 0.001) and in activity level and vigilance subdomains (both p < 0.001). The HADS-anxiety scores decreased by 1.94 ± 3.94 (p = 0.059) and depression scores by 3.06 ± 2.05 (p < 0.001) in the intervention group, with significant between-group differences for both anxiety (p = 0.008) and depression (p < 0.001). Conclusion Pranayama was an effective adjunct therapy for these OSAS patients, and incorporating it into treatment strategies may enhance patient outcomes. Clinical trial registration number/date NCT04632147/22.10.2020.
Sun-macerated hypericum perforatum oleates in fixed oils: Analytical characterization and comparative wound-healing activity
(The Scientific and Technological Research Council of Türkiye (TÜBİTAK), 2026) Çapar, Cihan; Küpeli, Esra; Yaba, Aylin; Parmaksız, Ayhan; Sümer, Engin; Yeşilada, Erdem
Background/aim: Hypericum perforatum L. oleates prepared in fixed oils have long been used for wound management due to their antiinflammatory, antibacterial, and tissue-regenerative properties. The bioactivity of these oleates is mainly attributed to hypericin, hyperforin, and pseudohypericin. In the present study, the wound-healing potential of H. perforatum oleates prepared in different fixed oils, including Olea europaea L. (olive), Sesamum indicum L. (sesame), Helianthus annuus L. (sunflower), and Nigella sativa L. (black seed), is compared. Materials and methods: Fixed oils were characterized by gas chromatography–mass spectrometry, while oleuropein (olive oil) and thymoquinone (black seed oil) were quantified by high-performance liquid chromatography, and sesamin and sesamol (sesame oil) by spectrophotometry. Oleates were prepared using the traditional sun maceration method. Hypericin, hyperforin, and pseudohypericin were quantified by liquid chromatography–mass spectrometry and ultraviolet spectrophotometry. In vitro and in vivo assays were performed to assess the wound-healing activities of both the fixed oils and their respective oleates. Results: All oleates exhibited significantly greater wound-healing activity than the corresponding fixed oils. The most pronounced synergistic effects were observed with the olive oil and sesame oil oleates. Conclusion: Maceration of H. perforatum in fixed oils enhances the intrinsic therapeutic properties of oils and contributes to improvements in multiple wound-healing parameters. The findings of the present study support the traditional use of H. perforatum oleates and provide a scientific basis for their pharmacological development.
