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
Comparative evaluation of a new-generation HBsAg assay versus a conventional method in occult HBV infection and low-level HBsAg positivity
(Ankara Microbiology Society, 2026) Daşdemir, Ferhat Osman; Dinç, Harika Öykü; Sirekbasan, Serhat; Hamzeli, Nur; Alaçam, Sema; Karabulut, Nuran; Türk, Süreyya; Dereli, Nida; Akçin, Rüveyda; Kocazeybek, Bekir
This study aimed to comparatively evaluate the conventional hepatitis B surface antigen (HBsAg) assay and the next-generation HBsAg NEXT (HBsAgNx) assay in samples with low-level HBsAg positivity and in cases of occult hepatitis B infection (OBI). A total of 497 individuals were included in the study, comprising 300 individuals with low-level HBsAg positivity, 100 OBI cases (64 seropositive and 36 seronegative) and 97 healthy controls. Serum samples were analyzed using the Abbott ARCHITECT HBsAg Qualitative II assay (Abbott Diagnostics, Wiesbaden, Germany) and the Abbott Alinity i HBsAg NEXT assay (Abbott Diagnostics, Wiesbaden, Germany). The presence of HBV DNA was confirmed by real-time polymerase chain reaction (Rt-PCR) using the COBAS AmpliPrep/COBAS TaqMan HBV test v2.0 (Roche Diagnostics, Mannheim, Germany). HBV DNA (Rt-PCR) was accepted as the gold standard reference for diagnostic performance evaluation. To minimize potential bias arising from sample selection, individuals with low level HBsAg positivity and OBI cases were analyzed separately. In the low-level HBsAg-positive group, semi-quantitative S/CO values of the assays were compared, whereas in the OBI group, only the detection rates of HBV DNA–positive cases were evaluated. A total of 17 OBI cases (17%) were identified that were tested negative by the conventional assay but positive by the HBsAgNx assay. Differences between the assays were evaluated using the McNemar test and p< 0.05 was considered statistically significant. Median values obtained with the HBsAgNx assay were significantly higher than those obtained with the conventional assay (p< 0.001). The HBsAgNx assay provides clinically significant contributions particularly in the OBI group, by detecting cases that cannot be identified by conventional assays. These findings indicate that the integration of high-sensitivity HBsAg assays into current HBV diagnostic algorithms would increase case detection and contribute to both transfusion safety and the clinical management of OBI.
Comparative benchmarking of 2d lidar slam algorithms with ros 2 on raspberry pi 5
(IEEE, 2026) Şahin, Ulaş; Can, Göktürk; Altıok, Ezgi; Çavdar, İbrahim; Gözüaçık, Necip
Mobile robotics increasingly relies on SLAM for robust autonomous navigation. While many algorithms exist, systematic comparisons within the ROS 2 framework under real-world conditions remain limited. This study addresses this gap by benchmarking three widely used 2D LiDAR-based methods—GMapping, Hector SLAM, and Cartographer—on a wheeled mobile robot. Using both simulation and on-device experiments, we evaluate mapping accuracy, localization quality, and computational efficiency. Results show that Cartographer achieves the highest accuracy in structured environments, Hector SLAM demonstrates robustness without odometry, and GMapping performs reliably only in small-scale settings. These findings highlight trade-offs relevant to embedded deployment. The main contributions are: (i) a reproducible evaluation pipeline on ROS 2, (ii) quantitative analysis of accuracy versus resource usage on Raspberry Pi 5, and (iii) practical guidelines for algorithm selection in autonomous systems. This work advances the understanding of ROS 2-based SLAM and supports informed deployment in robotics applications.
Ibuprofen and nimesulide derivatives selectively induce apoptosis in HER2-positive breast cancer via inhibition of the PLA₂–COX-2–NF-κB pathway
(Springer Nature Link, 2026) Çakırlı, Egemen; Bedir, İpek; Biliz, Yağmur; Yılmaz, Özgür; Küçükgüzel, Şükriye Güniz; Telci, Dilek
Background Chronic inflammation contributes to breast cancer development through the phospholipase A₂ (PLA₂)–cyclo oxygenase-2 (COX-2)–nuclear factor κB (NF-κB) cascade, which regulates prostaglandin synthesis, oxidative stress, and transcription of pro-inflammatory and anti-apoptotic genes. This pathway is particularly active in HER2-positive breast can cer, promoting proliferation, invasion, and resistance to apoptosis. Non-steroidal anti-inflammatory drugs such as ibuprofen and nimesulide target COX enzymes and have shown potential in suppressing inflammation-driven tumorigenesis. In this study, we evaluated the anticancer and anti-inflammatory activity of newly synthesized, structurally modified ibuprofen and nimesulide derivatives designed to modulate PLA₂–COX-2–NF-κB axis. Methods and Results Cytotoxicity was assessed in HER2-positive breast cancer cells (AU565 and SKBR3) and compared with normal dermal fibroblasts (HDF) and breast epithelial cells (MCF-12A), using WST-1 assays. Apoptosis, cell cycle distribution, caspase-3/7 activation, and ROS generation were analyzed by imaging-based assays, flow cytometry, and fluo rescence methods. Gene expression of PLA2G2A and PTGS2 was quantified by qRT-PCR, and NF-κB translocation was analyzed by immunocytochemistry. Two ibuprofen triazole derivative (D1) and ibuprofen thioether derivative (D7) and one nimesulide derivative (D8) significantly reduced cell viability in a dose-dependent manner without affecting normal cells. These derivatives induced G₀/G₁ arrest, caspase-3/7 activation, ROS reduction, and increased late apoptosis. Downregula tion of PLA2G2A and PTGS2 expression and inhibition of NF-κB translocation confirmed disruption of the PLA₂–COX-2– NF-κB cascade. Conclusion These findings demonstrate that structurally optimized ibuprofen and nimesulide derivatives exert dual anti inflammatory and anticancer effects in HER2-positive breast cancer by suppressing PLA₂–COX-2–NF-κB pathway and promoting apoptotic cell death.
Synthesis, characterization, biological evaluation, and molecular modeling of novel nimesulide urea derivatives as potential MetAP2 inhibitors
(Nature Research, 2026) Yılmaz, Özgür; Biliz, Yağmur; Kuloğlu, Elif; Arancı, Kübra; Erdoğan, Ömer; Çevik, Özge; Karahasanoğlu, Müfide; Mert Şahin, Naz Mina; Çakır, Ayşe Buse; Tuzcu, Bilge; Yelekçi, Kemal; Küçükgüzel, Şükriye Güniz
A series of nimesulide-derived ureas were synthesized in high yields (69- 91%) via a novel synthetic method under organotin catalysis. The structural characterization of the synthesized compounds was determined using a variety of spectroscopic methods, including ¹H NMR, ¹³C NMR, FTIR, and HRMS. Following initial screening, selected compounds were further evaluated using specific biological assays, including cytotoxicity analysis, apoptosis assessment by Annexin V/PI staining, analysis of Bax and Bcl-2 protein expression, and detection of DNA fragmentation using AO/EB staining. These evaluations were carried out in a variety of cell lines, including MDA-MB-231 (human triple-negative breast cancer cells), HeLa (human cervical cancer cells), PC-3 (androgen-independent human prostate cancer cells), MKN-45 (human gastric cancer cells), U87 (human glioblastoma cancer cells), and HUVEC (human umbilical vein endothelial cells). Three of the compounds demonstrated efficacy in MDA-MB-231 cells, resulting in increased AO/EB staining and annexin-V-PI binding levels, and increased Bax/Bcl-2 ratios. Numerous studies implicate MetAP2 in angiogenesis. MetAP2 stimulates cancer cell proliferation when it is upregulated and appears to play an essential role in tumor progression. In connection with the cell lines studied in this study, a crucial MetAP2 enzyme target was selected for in silico studies to support the experimental outcomes. The three promising compounds have been demonstrated to accelerate cell apoptosis and inhibit cell division by targeting MetAP2. The compounds synthesized in this study potential to overcome the challenges of targeted therapies in triple-negative breast cancer. Alongside these findings, the antioxidant potential of the synthesized compounds was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. One of the compounds exhibited a radical scavenging activity comparable to the reference standard. In-silico molecular modeling studies were conducted in the final phase to evaluate the newly designed inhibitors as potential anticancer and antioxidant drug candidates. The most likely conformations of the MetAP2-ligand complex were sorted according to the free energy of binding score (kcal/mol) and agree with the experimental inhibition values. The computational results suggest that the newly synthesized compounds may be potential anticancer drug candidates.
Scientific accuracy of large language models in tilted implant dentistry: A guideline-based comparative evaluation
(Wolters Kluwer, 2026) Yıldız, Mehmet S.; Alkap, Melek; Özdal, Umut; Özdal Zincir, Özge
Tilted dental implant systems are widely used in the rehabilitation of anatomically compromised jaws and are supported by international consensus guidelines. Concurrently, large language models (LLMs) are increasingly accessed as informational tools in implant dentistry; however, their scien tific accuracy and adherence to guideline-based principles in advanced implant concepts remain insufficiently explored. This study evaluated the scientific accuracy, guideline conformity, and clinical consistency of responses generated by 4 LLMs regarding tilted dental implant systems. A total of 120 guide line-based questions covering 8 predefined domains (definition, indications, contraindications, advantages, surgical procedure content, prosthetic procedure content, complications, and prognosis/survival) were developed in accordance with ITI, EAO, and AAOMS consensus reports. Each question was in dependently submitted to ChatGPT-5.2, Copilot, DeepSeek, and Gemini, and all responses were anonymized and evaluated by a multidisciplinary expert panel using a structured ordinal scoring system. Overall, scientific accuracy scores were high across all models, with near-ceiling performance observed in domains related to indications, advantages, procedural con tent, and prognosis. Statistically significant between-model differences were identified in the definition (P = 0.003), con traindications (P = 0.006), and complications (P < 0.001) do mains, with DeepSeek and Gemini demonstrating consistently higher scores in complication-related content compared with ChatGPT and Copilot. Within-model analyses further revealed significant domain-dependent variability across all LLMs. Al-though LLMs demonstrate a strong capacity to reproduce es tablished, guideline-based knowledge regarding tilted implant systems, limitations remain in safety-critical domains requiring nuanced clinical judgment. Accordingly, LLMs should be re garded as adjunctive educational tools rather than substitutes for expert decision-making in craniofacial implantology.
