İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
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Güncel Gönderiler
Green-synthesized CuO/Cu2O-supported g-C3N4 p–n junction photocatalyst for photo(electro)catalytic hydrogen evolution
(Elsevier, 2026) Kaba, İbrahim; Kılıç, Behris; Bozkurt, Rabia Nur; Koca, Atıf
In this study, an environmentally friendly CuO/Cu2O nanoparticle (NPs) production method was developed using waste rosehip seed plant extracts as reducing and stabilizing agents. Automatic solvent extraction (ASE) with a green 60% (v/v) ethanol/water solvent combination produced polyphenol-rich solutions for biogenic nanoparticle production. Green CuO/Cu2O NPs were loaded onto n-type graphitic carbon nitride (g-C3N4, CN) at 5%, 10%, and 15% weight percentages to form p-n heterojunction photocatalysts (5CuO/Cu2O@CN, 10CuO/Cu2O@CN, and 15CuO/Cu2O@CN). Structural and morphological analyses and material characterizations performed using XRD, FTIR, SEM-EDS, TEM, XPS, UV–vis DRS, Zeta Sizer, and DLS confirmed the successful formation and homogeneous distribution of CuO/Cu2O on the CN surface. Optical and photoelectrochemical characterizations revealed that the formation of p–n type junction significantly increased visible light absorption and supported efficient charge carrier dissociation. Photoelectrochemical (PEC) measurements yielded consistent results for photocatalytic hydrogen (H2) evolution, with a consistent H2 evolution relationship; pure CN produced 125 μmol g− 1 h− 1 H2, while the 10CuO/Cu2O@CN sample produced 937 μmol g− 1 h− 1 H2, increasing performance by approximately 7.5-fold. Furthermore, this study aimed to contribute to a more environmentally friendly and sustainable approach by using lactic acid as a sacrificial material to facilitate hole consumption. In addition to photocatalytic activity, the antioxidant properties of the photocatalysts were evaluated using 2,2-diphenyl-1-picrylhydrazil (DPPH) free radical scavenging method, and composition-dependent radical scavenging efficiencies were determined.
Real-world comparison of short-term adverse events, treatment persistence, and efficacy of semaglutide and tirzepatide: A nationwide multicenter study
(Karger, 2026) Hepşen, Sema; Haymana, Cem; Ertepe Küçükgöde, Gizem; Özcan, Büşra; Özbaş, Burak; Or Koca, Arzu; Aydoğan, Berna İmge; Tura Bahadır, Çiğdem; Salman, Serpil; Sönmez, Alper
Introduction: Real-world data directly comparing the safety, tolerability, and effectiveness of semaglutide and tirzepatide in patients with obesity remain limited. This nationwide multicenter observational study compared short-term adverse events, treatment discontinuation, body weight loss (BWL), and metabolic outcomes between the two treatments. Methods: This study included 2,549 patients with obesity treated with semaglutide (n=1,434) or tirzepatide (n=1,115). Adverse events, including time to onset, dose at occurrence, and related discontinuation, were evaluated. Changes in BWL and metabolic parameters up to 6 months were assessed. Subgroup analyses were performed in patients with and without type 2 diabetes mellitus (T2DM). Results: At least one adverse event occurred in 50.9% in the semaglutide group and 51.0% in the tirzepatide group (p=0.524), with gastrointestinal events the most frequently reported. Overall adverse event rates were comparable between groups; however, musculoskeletal and allergic reactions were more common in the tirzepatide group. The onset of gastrointestinal, neuropsychiatric, musculoskeletal symptoms, and hypoglycemia occurred earlier in the tirzepatide group. Discontinuation due to adverse events was similar between groups, except for pancreatic events, which were more frequent in the semaglutide group (p=0.006). Tirzepatide was associated with greater early BWL at all time points. At 6 months, median percentage BWL was 12.6% with semaglutide and 14.4% with tirzepatide. HbA1c reductions were comparable between groups in patients with T2DM. Conclusion: In real-world clinical practice, semaglutide and tirzepatide show similar short-term tolerability and treatment persistence, although tirzepatide is associated with a higher incidence of musculoskeletal and allergic reactions and greater early BWL.
Post-processing protocols in 3d printed dental restorations: A literature-based data analysis
(Dennis Barber Journals, 2025) Mert, Selen Elif; Özkan, Yiğit Alp; Olkun, Abdullah Yaşar; Dilaverler Yardım, Esra Ayşe
Objectives: This literature-based data analysis aims to evaluate the effects of post-processing protocols on the physical, mechanical, and surface properties of dental restorations produced using 3D printing technologies (SLA, DLP, and LCD systems). The objective is to highlight the variability in current approaches and thematically analyze the clinical implications of these differences. Materials-methods: A systematic search of the literature published between 2018 and 2025 was conducted using PubMed, Scopus, and Web of Science databases, in accordance with PRISMA guidelines. Inclusion criteria were: (1) studies involving 3D printed resins, (2) evaluation of at least one post-processing variable (e.g., curing, cleaning, or support removal), and (3) focus on definitive or interim prosthodontic restorations. Studies involving orthodontic models, aligners, or CAD/CAM-milled restorations were excluded. The included studies were categorized into three groups: curing protocols, cleaning procedures, and support structure removal. Due to methodological heterogeneity, no meta-analysis was performed; instead, findings were interpreted through a descriptive, literature-based data analysis approach. RESULTS: A total of approximately 320 unique studies were identified through prior systematic and narrative reviews. After applying predefined inclusion criteria, 12 studies were selected for in-depth evaluation in this literature review. Although some included studies were systematic reviews and meta-analyses, this study did not perform an independent meta-analysis. Variations in curing time, light intensity, and atmospheric conditions were found to affect degree of conversion, microhardness, and flexural strength. Cleaning protocols involving different solvents and application techniques influenced surface roughness and dimensional accuracy. The support removal process impacted marginal adaptation, surface integrity, and gloss retention. Despite methodological differences, the overall evidence indicates that post-processing parameters significantly influence clinical performance outcomes. Conclusion: This analysis demonstrates that post processing protocols significantly affect material quality and clinical applicability. The findings underscore the need for manufacturer-independent, standardized protocols to ensure predictable outcomes in 3D printed dental restorations.
Weibull characteristics and modulus calculation in adhesion studies: A methodological investigation
(Dennis Barber Journals, 2025) Berisha, Florentin; Şener, Alpaslan; Cankja, Angelo; Uzun Pekintürk, Berre; Freitas Brum Souza, Luiza; Özcan, Mutlu
Objective: This study aimed to determine the minimum number of specimens required to obtain statistically reliable conclusions in adhesion studies using the Weibull statistic and to estimate the probability of failure under defined conditions. Materials-methods: Specimens (N=160) were prepared from resin composite (RC: Brilliant, Coltene), lithium disilicate (LD: IPS e.max Press, Ivoclar), zirconia (YZ: Z-CAD, Metoxid AG), and titanium (TI: Ti CP Grade 4, Permascand). RC, YZ, and TI were air-abraded (50 µm Al2 O2 , 2.5 bar, 10 s), and LD was etched with 5% hydrofluoric acid (20 s). Resin cement cylinders (Ø=3×4 mm) were bonded using one of the following: Variolink Esthetic DC (Ivoclar), Panavia V5 (Kuraray Noritake), Panavia 21 (Kuraray Noritake), or Multilink Automix (Ivoclar). The combinations tested were as follows: RC-Variolink Esthetic DC/Panavia V5; LD-Variolink Esthetic DC/Panavia V5; YZ-Panavia 21/Multilink Automix; TI Panavia 21/Multilink Automix. Half of the specimens were stored at 37 °C for 24 h; the other half underwent thermocycling (x6000, 5-55 °C). Shear bond strength was tested (1 mm/min), and failure modes were assessed under digital microscopy. Weibull analysis evaluated bond reliability for 10, 20, 30 and 40 specimens in each group. Maximum likelihood estimation and 95% confidence intervals determined differences. Results: For RC, Variolink Esthetic DC showed higher characteristic strength (η) at n=10 and 20 vs. n=30 and 40. Panavia V5 showed a significant decrease from n=10 to 40 only in the non-aged condition. In LD, both cements showed decreasing η with increasing n. In YZ and TI, both Panavia 21 and Multilink Automix showed reduced characteristic strength with increasing n. Failures were mainly cohesive in LD but adhesive with the other materials. Conclusions: Increasing sample size reduced characteristic strength (η) across all materials, indicating that small sample sizes overestimate adhesive performance. Larger samples yield more reliable estimates. The Weibull modulus (β) remained stable or increased slightly after aging, especially for zirconia.
Prosthetic rehabilitation of a large maxillary defect due to nasopharyngeal tumor resection: A case report
(Dennis Barber Journals, 2025) Topuz, Buğra Tuğ; Kasıl, Ece; Ayvalıoğlu Şamiloğlu, Demet Çağıl
Introduction: Nasopharyngeal tumors are malignant neoplasms located in the epithelial lining of the nasopharynx, and they often require aggressive treatment modalities including surgery, radiotherapy, and/or chemotherapy. Surgical resection of these tumors, especially when involving adjacent maxillary and palatal structures, frequently results in large maxillofacial defects. This case report presents the comprehensive prosthetic rehabilitation of a patient with a large acquired maxillary defect following surgical resection of a nasopharyngeal tumor. Case Description: A 49 years old male patient with a large maxillary defect resulting from extensive surgical nasopharyngeal tumor resection applied to the clinic of Department of Prosthodontics. Following surgery, the patient had received postoperative radiotherapy and chemotheraphy. Prior to definitive prosthetic rehabilitation, endodontic and periodontal treatments of the remaining teeth were completed. Support was taken from the remaining teeth (16-15, 12-11-21- 22) to fabricate a precision attachment-retained obturator that provided partial separation between the oral and nasal cavities. A quadrilateral design was performed. For the mandibular partial edentulism, a precision attachment-retained, metal framework removable partial denture was designed. Results: The patient’s issues with speech and nutrition deficiency were resolved with the obturator prosthesis and the esthetic demands were fullfilled. Conclusion: Within the scope of this case, the use of an obturator provided functional and esthetic rehabilitation of a patient with a large maxillary defect following oncologic surgery.
