WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Conference Object Thermal Stability and Conformational Changes of Ubiquitin Upon Interaction with Few-Layer Graphene: An Optical Spectroscopy Approach(Springer, 2025) Gencay, Burcu; Guler, GunnurConference Object Reagent-Free Urea Determination From Hemodialysis Fluid: Development of FT-IR Spectroscopic Strategies(Springer, 2025) Akyuz, Ersed; Tanrisev, Mehmet; Guler, GunnurArticle Cryofixation Strategy for Fabrication of Robust Gelatin-Polyester Conductive Biocomposites(Taylor & Francis Inc, 2026) Koksal, Busra; Onder, Ahmet; Yildiz, Umit HakanThe development of mechanically robust and electroconductive biomaterials is critical for advancing tissue engineering strategies, particularly in neural, cardiac and musculoskeletal applications. Here, we report a polycaprolactone (PCL)-gelatin conductive polymer (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, PEDOT:PSS) biocomposite with tunable mechanical and electrical properties, fabricated via the cryofixation process relying on rapid reaction between isocyanate-terminated PCL, gelatin and PEDOT:PSS. Two isocyanate sources, hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI) were employed to obtain reactive end-functionalized PCLHDI and PCLIPDI. The cryofixation (at -18 degrees C) of PCLHDI or PCLIPDI, gelatin and PEDOT:PSS was found to occur in unfrozen microdomains and enabled the resultant gel with an inherited network of ice, thereby increasing porosity. Electroconductivity was introduced via the incorporation of PEDOT:PSS, yielding conductive cryogels with porous morphology. The resulting scaffolds exhibited a Young's modulus of 637 Pa and electrical conductivity of 197 mu S/cm, alongside biocompatible nature of gelatin-based gels. This multifunctional platform offers significant promise for the engineering of electrically active tissues.Article FW-S3PFCM: Feature-Weighted Safe-Semi Possibilistic Fuzzy C-Means Clustering(Springer, 2026) Khezri, Shirin; Aghazadeh, Nasser; Hashemzadeh, Mahdi; Golzari Oskouei, AminThe safe semi-supervised fuzzy c-means clustering (S3FCM) method is a well-known clustering method that can produce successful results by incorporating prior knowledge of the class distribution. Its process is fast and simple but still has two limitations. The first issue is that it gives equal weight to all data features, while in real-world applications, different features usually have different importance. Secondly, S3FCM is very sensitive to noise and outliers. This paper proposes an extension of the S3FCM, entitled FW-S3PFCM, to mitigate these shortcomings. The proposed method uses a local feature weighting scheme to consider the different feature weights in the clustering process. Additionally, a possibilistic version of the S3FCM is designed to reduce the sensitivity to noise and outliers. The effectiveness of the proposed method is comprehensively evaluated on various benchmark datasets, and its performance is compared with the state-of-the-arts methods. To practically asses the FW-S3FCM, a real-world dataset of brain MRI images and its segmentation performance are analyzed as well. The average Accuracy, F1-score, Sensitivity, and Precision measures obtained by FW-S3FCM are 0.9682, 0.9826, 0.9743, and 0.9925, respectively, which are better than the competitors' performance.Article Alterations in Secondary Lipids Are Associated with Neuroinflammation in the Brain of Neu1-Deficient Mice(Springer, 2026) Ada, Ebru; Seyrantepe, VolkanNeu1 (lysosomal sialidase 1) is essential for removing sialic acid from oligosaccharides and glycoconjugates. Neu1 deficiency impairs lysosomal digestion, leading to sialidosis and sialoglycoprotein accumulation. It also increases lipids, including gangliosides GM3, GD3, GM4, and LM1, in the kidney, liver, and spleen. Neu1-/- mice display symptoms resembling Type II sialidosis, including enlarged spleen and liver, kidney issues, neurological problems, spinal defects, and oligosaccharide buildup. The study examined secondary lipid alterations and inflammation in the cortex and cerebellum of these mice. Lipidomic, molecular, and immunohistochemical analyses of tissues from 2 and 5 M Neu1-/- mice revealed reduced levels of lipids, including PC, PE, PS, and CL, along with increased pro-inflammatory cytokines and loss of oligodendrocytes and neurons. Signs of astrogliosis and microgliosis emerged in specific brain regions. These results indicate that reduced levels of glycerophospholipids could serve as an indicator of inflammation in sialidosis mice. Future research should investigate therapies targeting these lipid changes, as modulating glycerophospholipids might slow disease progression in sialidosis patients.Article Gamma Secretase Inhibitors, DAPT and MK0752, Exhibit Synergistic Anticancer Effects with Cisplatin and Docetaxel in 2D and 3D Models of Breast Cancer(TÜBİTAK Scientific & Technological Research Council of Turkey, 2025) Telli, Kubra; Gubat, Johannes; D'Arcy, Padraig; Ozuysal, Ozden YalcinBackground/aim: Breast cancer remains a major malignancy among women, and severe side effects and the development of acquired drug resistance frequently hinder current therapeutic strategies. The Notch signaling pathway, a key regulator of cell fate, is commonly dysregulated in breast cancer and associated with poor prognosis. Gamma-secretase inhibitors (GSIs) block Notch receptor activation and have shown potential anticancer efficacy. This study aimed to investigate the synergistic activity of two commonly used GSIs, DAPT and MK0752, combined with docetaxel or cisplatin in both 2D and 3D breast cancer models. Materials and methods: Triple-negative, highly metastatic MDA-MB-231 and ER+/PR+ MCF-7 breast cancer cell lines were treated with DAPT or MK0752 alone or in combination with docetaxel or cisplatin. Drug efficacy and potential synergism were evaluated in 2D monolayer cultures and 3D spheroid models. Sequential treatment strategies were also assessed, where docetaxel or cisplatin was administered prior to GSI exposure. Results: Both MDA-MB-231 and MCF-7 cell lines exhibited notable sensitivity to DAPT and MK0752 combinations with docetaxel or cisplatin in 2D and 3D cultures. Synergistic enhancement of cytotoxicity was observed, particularly in sequential treatment regimens. Pretreatment with docetaxel or cisplatin followed by GSI exposure demonstrated superior growth inhibition compared with either monotherapy or simultaneous combination treatments. Conclusion: This study highlights the therapeutic potential of combining GSIs with standard chemotherapeutics to overcome drug resistance in breast cancer. The observed synergy and sequencing effects provide a strong basis for further mechanistic and translational investigations to optimize GSI-based combinational therapy strategies.Article Univariate Deep Learning Models for Short-Term Electricity Load Forecasting from Renewables(Ankara University, Faculty of Science, 2025) Kabran, Fatma Basoglu; Unlu, Kamil DemirberkRenewable energy offers a cost-effective, carbon-free solution for energy needs, while protecting the environment. Accurate forecasting of electricity generation from renewable sources is crucial for the efficiency of modern power grids. This study employs a univariate deep learning approach to predict daily renewable energy generation, evaluating Recurrent Neural Networks (RNNs) and Convolutional Neural Networks (CNNs) as candidate models. Five performance metrics-mean absolute error, root mean squared error, mean absolute percentage error, mean absolute scaled error and the coefficient of determination-are employed to assess the forecasting power of the algorithms. The empirical results show that CNN outperforms other models, achieving an R2 of almost 94%. This research shows that the univariate model based on historical data of electricity load generated from renewables can accurately predict day-ahead electricity load, even without meteorological data.Article Triple Helix Spaces: A Tale of Three Helices(Routledge Journals, Taylor & Francis Ltd, 2025) Kose, Suheda; Elburz, Zeynep; Velibeyoglu, Koray; Oner, Asli CeylanIn recent years, the Triple Helix model has gained prominence within academic circles. This study, situated in the field of city planning, aims to clarify the model's theoretical foundations, evaluate its measurement techniques, and explore the relationship between the Triple Helix and urban space. By examining 231 Triple Helix-related publications from the past 40 years (up to 12 July 2024, sourced from the Web of Science Core Collection), we propose a framework of three distinct generations for understanding Triple Helix spaces in urban contexts. The first-generation Triple Helix space is characterized by direct interactions among the three primary actors: university, industry, and government. The second-generation expands on this by including multiple interactions among the three main actors and their facilitators. The third-generation involves the circular interaction of multiple second-generation Triple Helix spaces. Across these generations, the study provides a lens for analyzing innovative urban spaces through Triple Helix interactions and offers practical approaches for examining the Triple Helix spaces. The findings also contribute to the theoretical foundation for the sustainable development of such spaces.Article Mass Spectrometric Profiling Reveals Alterations in N-Glycans and O-Glycans in Tay-Sachs Disease Under Autophagy-Induced Conditions(Springer, 2025) Can, Melike; Basirli, Hande; Jin, Chunsheng; Karlsson, Niclas G.; Bojar, Daniel; Seyrantepe, VolkanTay-Sachs disease is a rare neurodegenerative disorder caused by mutations in the HEXA gene. The HEXA gene encodes the alpha-subunit of the enzyme beta-hexosaminidase A, which degrades GM2 ganglioside. Previously, we identified impaired autophagy in the brains of a mouse model of Tay-Sachs disease, which exhibited neuropathological and clinical abnormalities. Moreover, we demonstrated autophagosome clearance in Tay-Sachs cells under lithium-induced conditions. Here, we further aimed to evaluate N- and O-glycan changes in these cells and examine whether glycan alterations are linked to ER stress. The profiles of N- and O-glycans were analyzed using LC-MS/MS in fibroblasts and neuroglial cells from 5-month-old Hexa-/-Neu3-/- mice and neuroglial cells from Tay-Sachs patients under lithium induction and nutrient deprivation. The expression levels of ER stress-related markers were assessed using qRT-PCR and Western blot analyses. We demonstrated higher levels of high mannose and lower levels of complex types of N-glycans, along with increased O-glycan levels in Tay-Sachs cells. Compared to control groups, we observed upregulated expression of endoplasmic reticulum (ER) stress-related markers, CHOP and ATF-6, in Tay-Sachs cells. Our study demonstrated that autophagy induction causes the degradation of accumulated high-mannose N-glycans and O-glycans, which is associated with the downregulation of ER stress-related genes in Tay-Sachs cells. Our study is the first to show this phenomenon in Tay-Sachs cells and suggests the presence of ER stress-mediated autophagy. Therefore, targeting glycans through autophagy induction could offer therapeutic benefits to patients with Tay-Sachs disease in future studies.Article Effects of Grain Refinement, Eutectic Modification, and T6 Heat Treatment on Tribological Properties of Al8Si3Cu Alloys(Springer India, 2026) Gurtaran, Mikdat; Uludag, MuhammetIn this study, the effects of grain refinement and eutectic modification on the wear behaviour of Al8Si3Cu cast alloys produced both before and after degassing were investigated in detail. Grain refinement and eutectic modification were conducted by adding AlTi5B1, Al3B, and AlSr15, respectively. Following the casting process, half of the samples were T6 heat-treated to evaluate the impact of heat treatment on their wear rate. Adhesive wear testing was conducted using a steel ball under a load of 3 N, at a speed of 8 mm/s over 20 m in dry and oily mediums. Microstructural characterisation was performed using optical microscopy and scanning electron microscopy. The results revealed that grain refinement enhances wear resistance by reducing the secondary dendrite arm spacing and strengthening the aluminium matrix. Conversely, while T6 heat treatment significantly promotes the precipitation of secondary phases and intermetallic compounds, improving wear resistance, it also results in more superficial wear on T6-treated samples, which can be attributed to insufficient surface wettability during the solution treatment stage of T6 heat treatment.
