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
Investigation of multiple resistance frequencies (antibiotic and heavy metal) of bacteria isolated from Gökçeada Island coastal marine sediment
(2025) Çiftçi Türetken, Pelin Saliha; Kalkan, Samet; Altuğ, Gülşen
Marine sediments are important reservoirs for antibiotics and heavy metals. Bacteria play a key role in polluted sedimentary habitats. This study aimed to identify heavy metal and antibiotic resistance in marine sediment bacteria isolated from Gökçeada Island in Turkiye. The samples were collected seasonally from 10 different sampling stations in 2015. Ninety isolates determined by VITEK 2 were tested against seven antibiotics using the disk diffusion method. The minimum inhibitory concentration values were measured against four heavy metal salts. The antibiotic resistance frequency rates were ordered as sulphonamides compound (93.3%), cefotaxime (78.9), ampicillin (77.8%), oxacillin (67.8%), rifampicin (57.8%), imipenem (1.1%), and oxytetracycline (0%). The heavy metal resistance ratios against ZnCl2, CuSO4, Pb(CH3COO)2, and HgCl2 were measured as 100%, 100%, 96.7%, and 73.3% respectively. The multiple heavy metal resistance index values were ranged from 0.75 (22.2%) to 1.0 (77.8%). The results show significant heavy metal and antibiotic contamination in the sediments of the Gökçeada Island. It is recommended that measures be taken against antibiotics and heavy metal pollution, as well as identifying and monitoring critical control points.
Evaluation of dental treatments in adult patients with special needs: a retrospective study
(Ataturk Universitesi, 2025) Bedir, Fatih; Atıcı Bedir, Makbule Gamze; Karadaş, Muhammet
Objective: Patients with special needs are at a higher risk of inadequate oral care, leading to dental caries or periodontal diseases. Therefore, this study aimed to retrospectively analyze the dental records of patients with special needs who received dental treatments under general anesthesia or sedation. Methods: A total of 186 cases (170 patients) of dental general anesthesia and sedation in adult patients with special needs were included in the study from January 2015 to April 2022. Demographic data, restorative treatments, tooth extractions performed under general anesthesia/sedation, secondary diseases, type of anesthesia, and American Society of Anesthesiologists (ASA) classification were obtained from patient files. Data were recorded as mean ± standard deviation (SD) or numerical value. Results: Of the 186 cases (mean age 28.55 ± 11.91 years), 134 (72 %) were performed under general anesthesia and 52 (28 %) under sedation. A total of 396 fillings, 775 extractions, 14 root canal treatments, and 93 scaling procedures were performed in 186 cases. On average, each case received 5.5 ± 3.4 teeth fillings, 4.5 ± 4.0 teeth extractions, and 1.6 ± 1.0 root canal treatments. Patients were classified as ASA I (n = 100) at most and ASA III (n = 5) at least. Conclusion: Patients with special needs have a high demand for dental treatment. In dental treatment of patients with special needs under general anesthesia/sedation, dentists prefer radical treatments such as tooth extraction.
Anticancer and immunomodulatory effects of a thiazolyl benzodiazepine targeting HSP90 in ER+ breast cancer
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Coşkun, Kübra Açıkalın; Tutar, Lütfi; Çifci, Kezban Uçar; Al, Mervenur; Koca, İrfan; Gümüş, Mehmet; Tutar, Yusuf
Background: Heat shock protein 90 (HSP90) is a molecular chaperone that stabilizes numerous oncogenic proteins and supports tumor survival. Small molecules targeting HSP90 offer a novel approach to overcome drug resistance and immune suppression in breast cancer. Methods: A novel thiazolyl benzodiazepine (TB) containing a hydrazone moiety was evaluated in breast cancer cell lines (ER+ MCF-7, TNBC MDA-MB-231, and HER2+ SK-BR-3). Cytotoxicity was assessed using the CCK-8 assay, followed by PCR sequencing, flow cytometry, RT-qPCR, protein profiling, and HSP90 binding assays. Results: TB showed the strongest activity in MCF-7 cells (IC50 = 7.21 µM) compared to MDA-MB-231 (IC50 = 28.07 µM) and SK-BR-3 (IC50 = 12.8 µM) cells. Mechanistic studies showed that TB binds to HSP90 (Kd = 3.10 µM), leading to disruption of the oncogenic signal. TB induced G2/M cell cycle arrest, promoted apoptosis via Bax and Caspase-3 activation, and suppressed cancer stem cell markers (NANOG, OCT4, SOX2). Additionally, TB activated immune-related pathways via ERK/MAPK signaling and upregulated genes such as SMAD2, SMAD3, and JUN. Conclusions: TB functions as an HSP90 inhibitor with dual anticancer and immunomodulatory properties in Estrogen Receptor-Positive (ER+) breast cancer cells. These findings suggest that TB represents a promising scaffold for the development of multi-targeted breast cancer therapies.
Minimizing delamination in CFRP laminates: experimental and numerical insights into drilling and punching effects
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Demiral, Murat; Saracyakupoglu, Tamer; Şahin, Burha; Köklü, Uğur
Carbon fiber-reinforced polymer (CFRP) laminates are extensively utilized in aerospace and advanced engineering fields because of their outstanding strength-to-weight ratio and superior fatigue durability. However, despite their high in-plane strength and stiffness, CFRP laminates are inherently susceptible to delamination. This weakness stems from the relatively low interlaminar strength of the resin-rich interfaces between layers compared to the much stronger in-plane fiber reinforcement. During mechanical processes such as drilling and punching, out-of-plane stresses and interlaminar shear forces develop, concentrating at these weak interfaces. This study investigates the delamination behavior of CFRP laminates with 3 to 7 plies under drilling and punching, focusing on the effects of ply count and drilling speed. Experimental tests were conducted using an 8 mm punch and drill bit at 2500, 3000, and 3500 rpm, reflecting typical workshop practices for M8 fastener holes. Scanning electron microscopy (SEM) analyses at different magnifications were used to quantify delamination extent. A three-dimensional finite element model was created in ABAQUS/Explicit, integrating the Hashin failure criterion to predict damage initiation within the plies and cohesive surfaces to simulate interlaminar delamination. The analyses show that with proper support, punching can approach the damage levels of drilling for thin CFRP plates, but drilling remains preferable for thicker laminates due to better integrity and tool longevity.
Synthesis and anticancer evaluation of some glycine conjugated hybrid compounds containing coumarin, thiophene and quinazoline moieties
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Çalışkan, Nedime; Menteşe, Emre; Yılmaz, Fatih; İlhan, Süleyman; Emirik, Mustafa
Background/Objectives: Cancer is one of the world’s leading causes of death. In 2022 alone, 9.74 million people died of cancer. It is estimated that this figure will rise to 10.4 million by 2025. Prostate and breast cancer are the most frequently diagnosed cancers in the world. Methods: Notably, compound 9f displayed the highest activity against both prostate cancer (PC-3) and breast cancer (MCF-7) cell lines. It was seen that substitution on the coumarin ring had a positive effect on anticancer activity (except chlorine substitution at the 6th position of coumarin), while it had a negative effect on the selectivity index (the ratio of IC50 calculated for healthy and cancer cells). Conclusions: The findings are consistent with the results obtained in the Molecular Docking study. Molecular docking studies were performed to investigate the binding affinities of the synthesized compounds towards kinesin-associated motor protein EG5, Human Ribonucleotide Reductase and Human Topoisomerase II, confirming their potent in vitro cytotoxicity against cancer cell lines. In accordance with the findings of experimental studies, compound 9f demonstrated the optimal docking binding scores.
