İstanbul Galata Üniversitesi Kurumsal Akademik Arşivi
DSpace@Galata, İstanbul Galata 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 telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Disaster management in Türkiye: a qualitative study on healthcare professionals
(2026) Mutlu, Hatice; Türkoğlu, Mesut Can; Erküvün, Kübra Sezen
Background Disasters pose complex challenges that extend beyond immediate emergency response, requiring well-coordinated, resilient, and health-centered disaster management systems. In disaster-prone countries such as Türkiye, understanding how health services, particularly specialized medical rescue teams, function in real disaster settings is critical for identifying systemic gaps and improving preparedness, coordination, and response capacity. The aim of this study is to examine the managerial and organizational challenges encountered in disaster management processes based on the experiences of UMKE personnel who have served during various disasters in Türkiye, and to derive implications for strengthening disaster preparedness and response capacity. Methods The study was conducted using a qualitative research design. In-depth interviews were carried out with healthcare professionals who participated in disaster response. The data were analyzed using thematic analysis, and the findings were categorized into five main themes: shortages of logistics and equipment; working conditions and training; social awareness; lack of coordination, communication, and organization; and institutional structure and local empowerment. Results The findings revealed that road damages hindered transportation and that alternative transportation plans were inadequate. Disaster training were not fully adapted to field conditions. Public disaster literacy was found to be low. Insufficient coordination and communication disrupted interventions. In addition, the study identified psychosocial support, community-based education, and institutional capacity building as critical components of effective disaster management. Conclusions This study was designed to capture the personal perspectives of healthcare professionals who directly confronted disasters and gained first-hand experience of related processes. Therefore, it provides a unique contribution by presenting a disaster management framework through the lens of healthcare professionals and by highlighting areas in need of improvement for policymakers in this field.
Comparison of color stability and wear resistance of different 3D printed definitive restorative resins
(2026) Gündoğan, Zülal Çoban; Özyılmaz, Özgün Yılmaz; Kara, Özlem
Statement of problem: Subtractive manufacturing in computer-aided design and computer-aided manufacturing (CAD-CAM) systems has been extensively studied, but additive manufacturing materials, particularly those used for definitive restorations, are relatively new and data regarding their clinical performance remain limited. Purpose: This in vitro study aimed to evaluate the color stability of 3 different 3-dimensionally (3D) printed definitive restorative materials under 5 different Commission Internationale de l'Eclairage illuminants and to compare their metameric color differences. In addition, the mechanical wear resistance of these materials was evaluated independently. Material and methods: A total of 135 specimens with thicknesses of 1.0, 1.5, and 2.0 mm were 3D printed according to the manufacturers' protocols. Color was evaluated before and after thermocycling under 5 illumination conditions (D65, D50, A, F11, F2). ΔE00 values were analyzed using mixed-design analysis of variance (α=.05). Wear was evaluated in 2.0-mm specimens using simulated mastication and volumetric analysis, and the wear data were analyzed using the Kruskal-Wallis test (α=.05) RESULTS: All specimens exposed to illuminant A exhibited clinically unacceptable color changes, regardless of material type or thickness. Under illuminants D50, F11, and F2, color changes were perceptible but remained within clinically acceptable limits. Thermal aging significantly reduced ΔE00 values (P=.001). Although wear was observed in all groups, no significant differences were found in volumetric loss (P=.139). Conclusions: Illuminants significantly influenced color stability across all resin types and thicknesses, whereas increased restoration thickness was associated with reduced color change perceptibility. In addition, no significant differences in wear volume were found among the tested 3D-printed definitive restorative materials.
Endocrine and metabolism modulating effects of paracetamol: From in vitro signaling to in vivo metabolic reprogramming in male mice
(Elsevier, 2026) Entezari, Bita; Bozdağ, Deniz; Buhur, Aylin; Sabuncuoğlu, Suna; Yavaşoğlu, Altuğ; Orhan, Hande Gürer
Obesity is a major global health challenge associated with a cluster of comorbidities, including metabolic syndrome and type 2 diabetes, necessitating a deeper understanding of the environmental factors contributing to this epidemic. This study investigated the in vitro adipogenic/lipogenic potential of paracetamol and its in vivo endocrine and metabolic modulating effects following prenatal exposure. Using the 3T3-L1 preadipocyte model, cells were exposed to paracetamol at physiologically relevant concentrations. Results demonstrated that paracetamol promoted lipid accumulation and upregulated G3PDH activity. Furthermore, low concentrations significantly increased the protein expression of key adipogenic regulators (PPARγ, C/EBPα, LPL, and SREBP1), suggesting interference with transcriptional cascades governing adipogenesis and lipogenesis. To assess in vivo effects, pregnant CD1 mice were exposed to paracetamol at three human relevant doses (Cmax/10, Cmax, and Cmax×10). In male F1 offspring, prenatal exposure resulted in increased anogenital distance and a higher incidence of sperm morphological abnormalities, indicating reproductive developmental alterations despite unchanged circulating hormone levels. Metabolically, offspring exhibited dyslipidemia characterized by elevated serum triglycerides and total cholesterol. Although body weight and glucose tolerance remained unaffected, lipidomic profiling of epididymal adipose tissue revealed pronounced remodeling, including the accumulation of neutral lipids and altered membrane phospholipid composition. This was accompanied by the upregulation of the adipogenic genes Pparγ, Lpl, and Fasn in adipose tissue. Collectively, these findings suggest that paracetamol may act as an endocrine modulator and metabolic disruptor when exposed prenatally, inducing latent metabolic dysregulation that may predispose offspring to metabolic syndrome later in life, even in the absence of overt obesity
Comparison of tensile bond strengths of different impression materials used with custom trays fabricated by 3D printing
(2026) Topalan, Onur; Özyılmaz, Özgün Yusuf
Background: This study aimed to evaluate and compare the tensile bond strength between four different impression materials and custom trays fabricated using various photopolymer-based threedimensional (3D) printing materials and one conventional method. Additionally, the effect of three surface treatments on bond strength was investigated. Methods: A total of 288 custom tray specimens were fabricated using four different techniques: Stereolithography (SLA), liquid crystal display (LCD), digital light processing (DLP), and a conventional light-cured urethane dimethacrylate (UDMA)-based acrylic. Each tray type was subjected to three surface treatments: adhesive-only, perforated-only, and perforated + adhesive. Four elastomeric impression materials were tested: polyvinylsiloxane, condensation silicone, polyether, and vinylsiloxanether. A standardized CAD model was used for all trays. The impression materials were applied onto the tray surfaces, and tensile bond strength was tested using a universal testing machine. Each condition was tested with six replicates (n = 6). Data were recorded in Newtons and converted to megapascal (MPa) using a standardized bonding surface area of 825 mm². Three-way ANOVA and Tukey’s post-hoc tests were conducted (α=0.05). Results: All three independent variables - printing technique, surface treatment, and impression material - had a statistically significant effect on tensile bond strength (p < 0.001). The highest mean bond strength (0.272 MPa) was observed with the DLP-printed tray using perforatedonly and polyether impression material. The lowest value (0.018 MPa) was found with the same tray type and surface treatment, but with condensation silicone. Among surface treatments, adhesive-only and adhesive + perforated trays showed significantly higher bond strengths compared to perforated-only groups (p = 0.001). Polyether showed significantly higher bond strength than all other impression materials, while condensation silicone yielded the lowest. Conclusions: Within the limitations of this in vitro study, tray fabrication method and surface treatment significantly influenced bonding with impression materials. The present findings may provide useful preliminary data for future clinical investigations evaluating retention characteristics of 3D-printed custom trays.
Volumetric Three-Dimensional Evaluation of the Pharyngeal Airway After Orthognathic Surgery in Patients with Skeletal Class III Malocclusion
(MDPI, 2025) Öz, Aslıhan Zeynep; El, Hakan; Öz, Abdullah Alper; Palemo, Juan Martin
Background: Orthognathic surgery significantly alters the dimensions of the pharyngeal airway. This study’s objective was to assess alterations in the pharyngeal airway volume via cone-beam computed tomography (CBCT) after orthognathic surgery in patients with skeletal Class III malocclusion. Methods: This retrospective study analyzed CBCT images from 23 patients with skeletal Class III malocclusion (13 females, 10 males), who were categorized into two groups based on the surgical approach: double-jaw and single-jaw surgery. The double-jaw group included 13 patients who underwent bilateral sagittal split osteotomy (BSSO) and Le Fort I osteotomy, whereas the single-jaw group included of 10 patients who had underwent BSSO only. CBCT images were evaluated both before surgery and at a minimum of three months after surgery. The oropharyngeal volume (OP), nasopharyngeal volume (NP), total airway volume, posterior airway space (PAS), and the most constricted area at the base of the tongue (minAx) were measured. Statistical analyses were performed using either paired t-tests or Wilcoxon signed-rank tests depending on data normality, with a significance level set at p < 0.01. Results: In the double-jaw group, a significant volumetric increase was observed in the nasopharynx (5316 ± 1948 mm3 to 6064 ± 1899 mm3 ; p = 0.010) and oropharyngeal volume decreased from 17,097 ± 5675 mm3 to 14,290 ± 5835 mm3 ; however, this reduction was not statistically significant (p = 0.017). In contrast, the single-jaw group showed a significant reduction in oropharyngeal volume from 15,620 ± 5040 mm3 to 12,444 ± 4701 mm3 (p = 0.010), with no significant change in nasopharyngeal volume (p = 0.551). Total airway volume significantly decreased only in the single-jaw group (from 20,452 ± 7754 mm3 to 16,846 ± 6529 mm3 , p = 0.010). Additionally, both groups exhibited marked decreases in PAS and minimum axial area values (all p < 0.01). Conclusions: Orthognathic surgery led to a significant volumetric increase in the nasopharynx in the double-jaw group, whereas the oropharynx volume significantly decreased only in the single-jaw group. Additionally, both surgical approaches resulted in a marked reduction in PAS and minimum axial area values, highlighting a notable impact on posterior airway dimensions.
