Uludag University Academic Repository
Not a member yet
50710 research outputs found
Sort by
Locoregional treatment in de novo bone-only metastatic breast cancer: Prospective, multi-institutional real-world data, BOMETIN, Protocol MF14-1a
Get PDFIntroduction: The impact of locoregional treatment (LRT) on survival in de novo bone-only metastatic breast cancer (dnBOMBC) is controversial. This study aims to assess the effect of LRT on survival, utilizing international, prospectively acquired data in this cohort of patients. Materials and Methods: Patients with dnBOMBC were divided into two groups: those receiving systemic therapy only (ST) and those undergoing LRT. Further, patients who received LRT were divided into two subgroups: those who received ST after LRT (LRT+ST group) and those who received ST prior to LRT (ST+LRT group). Factors associated with disease progression, including solitary or multiple bone metastases, were analyzed. Results: There was a total of 744 patients with dnBOMBC treated at each of the participating institutions between 2014 and 2022, with 372 (50%) participants in each arm. Median follow-up was 48 months (32–66, 25–75%). Patients in the LRT group were significantly younger than the ST group [50 (42, 60) vs. 55 (44, 66), p = 0.0001]. There were no significant differences in grade, HER2 status, triple-negative status, receipt of hormonal therapy, or intervention to metastatic sites. During follow-up, 58% (n = 217) of patients in the ST group and 32% (n = 120) of patients in the LRT group died (p < 0.001). Local progression was observed in 20% of the patients in the ST group, whereas 9% progressed in the LRT group (p = 0.0001). Systemic progression occurred more in the ST group; 66% (n = 244) compared to 41% (n = 152) of patients in the LRT group (p < 0.001). The hazard of death was 64% lower in the LRT group than in the ST group (HR: 0.36, 95% CI: 0.29–0.45, p < 0.0001). The burden of metastatic disease differed significantly between the two groups, with a higher rate of solitary bone metastases in the LRT group compared to the ST group (50% vs. 24%, p < 0.001). However, the LRT group had better overall survival (OS) for both solitary (HR: 0.38, 95% Cl: 0.26–0.55) and multiple (HR: 0.38, 95% Cl: 0.29–0.51) bone metastasis patients. Within the LRT group, survival rates were similar whether the breast surgery was performed before or after ST. Multivariate Cox analysis showed that LRT and ER/PR positivity significantly decrease the hazard of death (p < 0.05). Conclusions: Analysis of this large multi-institutional patient cohort provides further evidence that LRT is associated with longer OS and lower locoregional recurrence rates in patients with dnBOMBC. In breast cancer patients with bone-only metastases at presentation, the decision for LRT should be made through a multidisciplinary approach with consideration of surgical therapy at the primary tumor
Experimental and simulation acoustic study of rectangular plate vibration for exciter speaker
No full textThis study investigates the vibrational behavior of 15×15 cm rectangular metal and plastic plates using both finite element analysis (FEA) and experimental measurements. The research aims to compare simulation results with real-world experimental data to validate the accuracy of numerical models in predicting plate vibrations under excitation from a speaker. Initially, modal analysis is performed via FEA to determine the natural frequencies and mode shapes of the plates. The numerical simulations are conducted using appropriate boundary conditions and material properties to ensure realistic modeling. Subsequently, an experimental setup is designed to excite the plates using a modal hammer, modal shaker and sound exciter. Thus, the resulting vibrations are measured using accelerometers and acoustic microphone. The measured frequency response is then compared with the FEA predictions to assess discrepancies and potential sources of error. Results indicate that while the FEA models provide a good approximation of the experimental outcomes, differences arise due to material imperfections, boundary condition assumptions, and damping effects not fully captured in simulations. The findings contribute to a better understanding of plate vibration characteristics, with implications for applications in acoustics, structural engineering, and materials science
Matching some graph dimensions with special generating functions
Get PDFIn this work, we investigated the relationship between special generating functions, such as array polynomials and graph dimensions, including metric, multiset, outer multiset, and local multiset dimensions, using minimal monoid presentations. The present paper is founded on earlier contributions and we are concerned with resolving the matching issue. In this context, our focus is on the matching between graph dimensions and generator functions, a subject that has not been examined and is alluded to in Open problem 3 in the paper by A. S. Cevik [Matching some graph dimensions with special presentations, Montes Taurus J. Pure Appl. Math., 6 (2024), 78-89]. As part of this effort, we address the characterization of graphs with infinite multiset dimensions and provide a partial classification based on outer multiset, local multiset, and metric dimensions
Aggregate gradation as a key parameter in optimizing asphalt mixtures for wireless energy transmission
Get PDFThe increasing adoption of electric vehicles and the goal of reducing carbon emissions have steadily heightened interest in wireless power transfer (WPT) technologies within transportation infrastructure. This study aims to optimize the dielectric properties of asphalt pavement materials to improve WPT efficiency. Accordingly, four different asphalt mixtures are designed with maximum aggregate sizes of 12 mm, 19 mm, 25 mm, and 38 mm, and five specimens are produced for each mixture under laboratory conditions. The prepared specimens are placed between two coils with a 6 cm separation, and measurements are carried out in the 100-110 kHz range using a Vector Network Analyzer (VNA). The measurement results are compared with reference data in air, and the electromagnetic wave transmission performance of the asphalt samples is evaluated. The analysis findings showed that among the four mixtures, the mixture identified as M4-which has smaller aggregate sizes and a relatively high bitumen content-achieved the highest transmission efficiency (96.6 %). This superior performance stems from the mixture's dielectric properties being closer to those of air and from the decreased void ratio within the material, which together minimize electromagnetic losses. In addition, the consistent outcomes obtained for samples prepared from different mixtures validate methodological repeatability. The results indicate that selecting an appropriate asphalt composition can significantly enhance the efficiency of roadway-based wireless charging systems and offer a sustainable improvement proposal for electric vehicle infrastructure
Activation of polypropylene (pp) fiber surface with 1-vinyl-1,2,4-triazole and vinyl acetate: Synthesis, characterization, and application in cementitious systems
Get PDFRecently, the potential of recycled materials to improve the performance of concrete and other building materials has become an important research topic. It is known that various methods are applied to improve the tensile strength and energy absorption capacity of cementitious systems. One of the most common of these methods is the addition of fibers to the mixture. In this study, the effects of surface-modified polypropylene (PP) fibers obtained from recycled masks on the mechanical properties of mortar mixtures were investigated. In order to improve the matrix-fiber interface performance, 6 mm and 12 mm long recycled PP fibers were chemically coated within the scope of surface modification using 1-Vinyl-1,2,4-Triazole and Vinyl Acetate. With this modification made on the surface of PP fibers, we aimed to increase the surface roughness of the fibers and improve their adhesion to the matrix. Thus, we aimed to increase the mechanical properties of mortar mixtures as a result of the fibers performing more effectively in the concrete matrix. FTIR AND SEM-EDS analyses confirmed the success of the modification and the applicability of 1-Vinyl-1,2,4-Triazole and Vinyl Acetate to the fiber surface and showed that the fibers were successfully modified. It is seen that the fibers modified with Vinyl Acetate exhibit superior performance in terms of both the workability and strength performance of cementitious systems compared to the fibers modified with 1-Vinyl-1,2,4-Triazole. This study provides a significant contribution to sustainable construction materials by revealing the potential of using recycled materials in cementitious systems
An analysis of skill-based Turkish language questions used in central examinations (2018-2024) and sample questions published by the Ministry of National Education
Get PDFBu araştırmada, 2018-2024 yılları arasında yayımlanan Türkçe dersi örnek soruları ile Liselere Geçiş Sistemi (LGS) kapsamında uygulanan beceri temelli sorular, kazanım, bilişsel beceri ve kullanılan materyal açısından karşılaştırılmıştır. Bu çalışma, sınavla öğrenci alacak ortaöğretim kurumlarına ilişkin merkezî sınavdaki beceri temelli Türkçe sorularını (2018-2024) yayımlanan örnek sorularla sayı, oran, nitelik açısından karşılaştırarak materyal, bilişsel süreç, kazanım alanlarına göre sınıflandırmasını yapıp yorumlamayı amaçlamaktadır. Nitel araştırma desenlerinden biri olan doküman incelemesi yöntemiyle gerçekleştirilen çalışmada, Millî Eğitim Bakanlığı tarafından yayımlanan örnek sorular ve LGS’de yer alan beceri temelli sorular veri kaynağı olarak kullanılmıştır. Güvenirliği sağlamak için Miles Huberman veri analizi kullanılmıştır. Soruların dayandığı kazanımlar, hedeflediği bilişsel beceriler ve kullanılan materyaller tespit edilmiştir. Araştırma sonucunda, örnek sorular ile LGS sorularının büyük oranda benzer kazanımlara dayandığı ve kazanım açısından yüksek düzeyde bir uyumluluk gösterdiği belirlenmiştir. Bilişsel süreç açısından ise LGS sorularının belirli beceriler etrafında yoğunlaştığı görülmüştür. Grafik, tablo, görsel, metin materyallerinin hem örnek sorularda hem de LGS’de kullanıldığı ve örnek soruların LGS için yordayıcı bir etkiye sahip olduğu görülmüştür. Elde edilen bulgular, beceri temelli soruların öğrenciye kazandırmayı hedeflediği yeterliklerin değerlendirilmesi açısından önem arz etmektedir.In this study, Turkish language sample questions published between 2018 and 2024 and the skill-based questions implemented within the scope of the High School Entrance System (LGS) were compared in terms of learning outcomes, cognitive skills, and material used. This study aims to classify and interpret skill-based Turkish questions in the centralized examination for secondary education institutions admitting students through examination (2018–2024) in terms of quantity, proportion, and quality by comparing them with the published sample questions according to materials, cognitive processes, and learning outcomes. The research was carried out using document analysis, one of the qualitative research designs. The data sources consisted of sample questions published by the Ministry of National Education and questions included in the LGS exams. To ensure reliability, the Miles and Huberman data analysis method was employed. The study identified the learning outcomes the questions were based on, the cognitive skills they aimed to assess, and the types of materials used. As a result of the research, it was determined that the sample questions and LGS questions were largely based on similar learning outcomes and demonstrated a high level of alignment in this regard. In terms of cognitive skills, LGS questions were found to be concentrated around specific skills. It was observed that materials such as graphics, tables, visuals, and texts were used in both sample questions and the LGS, and that the sample questions had a predictive effect on the LGS. The findings are significant in terms of evaluating the competencies that skill-based questions aim to develop in students
The development of a fuzzy logic system using MATLAB for early detection of hereditary cancer in BRCA1/2 negative cases
No full textThe purpose of our study is to expedite cancer diagnosis through the development of software for rapid detection of hereditary breast cancer (BC) with negative BRCA1/2 on MATLAB, utilizing a fuzzy logic system with several variants of genes associated with BC. This system serves as a clinical decision-support tool, assisting in early classification and interpretation of genetic variants by combining clinical and genetic data. Clinical data were obtained from Erciyes University Faculty of Medicine Department of Medical Genetics and Uludağ University Faculty of Medicine Department of Medical Genetics. 488 individuals were studied. Only 90 of them were relevant to our investigation since their BRCA1/2 genes did not exhibit notable genetic mutations. We examined 16 distinct breast cancer risk factors and focused on mutations related to 18 hereditary BC genes. The collected data were integrated into the developed system, and various membership functions were given varying degrees of possibility, ranging from 0 to 1, depending on their participation in input clusters. After the system was trained on 90 cases and validated on six independent patients, its accuracy was assessed, yielding reliable results. Following the training phase, outcomes revealed the presence of two pathogenic variants at 0.92 (92%), two benign variants at 0.25 (25%), and two variants of unknown significance at 0.5 (50%). Given the high incidence of breast cancer, early prediction is paramount. Despite the emergence of fuzzy logic systems in medical applications, limited research akin to our study exists. The establishment of this artificial intelligence software holds promise for advancing the early detection of BC in future clinical applications
Enhancing the CAD-RADS™ 2.0 category assignment performance of ChatGPT and DeepSeek through "few-shot" prompting
Get PDFObjective: To assess whether few-shot prompting improves the performance of 2 popular large language models (LLMs) (ChatGPT o1 and DeepSeek-R1) in assigning Coronary Artery Disease Reporting and Data System (CAD-RADS™ 2.0) categories. Methods: A detailed few-shot prompt based on CAD-RADS™ 2.0 framework was developed using 20 reports from the MIMIC-IV database. Subsequently, 100 modified reports from the same database were categorized using zero-shot and few-shot prompts through the models' user interface. Model accuracy was evaluated by comparing assignments to a reference radiologist's classifications, including stenosis categories and modifiers. To assess reproducibility, 50 reports were reclassified using the same few-shot prompt. McNemar tests and Cohen kappa were used for statistical analysis. Results: Using zero-shot prompting, accuracy was low for both models (ChatGPT: 14%, DeepSeek: 8%), with correct assignments occurring almost exclusively in CAD-RADS 0 cases. Hallucinations occurred frequently (ChatGPT: 19%, DeepSeek: 54%). Few-shot prompting significantly improved accuracy to 98% for ChatGPT and 93% for DeepSeek (both P<0.001) and eliminated hallucinations. Kappa values for agreement between model-generated and radiologist-assigned classifications were 0.979 (0.950, 1.000) (P<0.001) for ChatGPT and 0.916 (0.859, 0.973) (P<0.001) for DeepSeek, indicating almost perfect agreement for both models without a significant difference between the models (P=0.180). Reproducibility analysis yielded kappa values of 0.957 (0.900, 1.000) (P<0.001) for ChatGPT and 0.873 [0.779, 0.967] (P<0.001) for DeepSeek, indicating almost perfect and strong agreement between repeated assignments, respectively, with no significant difference between the models (P=0.125). Conclusion: Few-shot prompting substantially enhances LLMs' accuracy in assigning CAD-RADS™ 2.0 categories, suggesting potential for clinical application and facilitating system adoption
The validity and reliability study of the turkish version of the health behavior scale for cancer patients
No full textAIM: The aim of the study was to conduct a validity and reliability study of the Health Behavior Scale for Cancer Patients and to adapt the scale to the Turkish language and culture. METHODS: The research is a methodological study. The sample consisted of a total of 440 cancer patients who came to the outpatient chemotherapy unit and oncology outpatient clinic of a university hospital and followed the social media accounts of a cancer-related association. Patients aged 18 and over and with at least a primary school education were included in the study. Data were collected between January and December 2022 with the Descriptive Characteristics Form and The Health Behavior Scale for Cancer Patients. For the validity analysis, language equivalence, content validity, exploratory and confirmatory factor analyses were performed. For the reliability, internal consistency, item-total score correlation, and test-retest were performed. RESULTS: According to the exploratory factor analysis, a two-factor structure was obtained and confirmed by confirmatory factor analysis. According to the factor loadings (0.60-0.87), total variance explained (61.575), and fit indices, the construct validity of the scale was found to be sufficient. In the reliability analyses, Cronbach's alpha internal consistency coefficient (0.85) was found to be highly reliable. It was determined that there was a very strong relationship between the pre-test and the post-test (r = 0.87, p < .001). CONCLUSION: The Health Behavior Scale for Cancer Patients has been revealed to be a valid and reliable measurement tool suitable for Turkish culture. Using this scale, cancer patients' adherence to medical health services and individual protective health behaviors can be determined
Compressed natural gas storage and delivery installation technologies
No full textBu tezde, sıkıştırılmış doğal gaz (CNG) dolum istasyonlarının termodinamik davranışı, sistem bileşenlerinin dinamik etkileşimi ve tasarım parametrelerinin optimizasyonu çok disiplinli ve bütüncül bir yaklaşımla analiz edilmiştir. İlk olarak, farklı doğal gaz karışımları için sıcaklık ve basınca bağlı olarak özgül hacim, entalpi, entropi, sıkıştırılabilirlik faktörü ve ses hızı gibi termodinamik özellikler hesaplanmış, bu kapsamda doğrulama amacıyla AGA8-DC92 denklemi uygulanmış, esas modelleme sürecinde ise CoolProp kütüphanesi ile daha esnek ve kapsamlı hesaplamalar yapılmıştır. Hesaplanan veriler, Simulink ortamında geliştirilen fiziksel modele aktarılmış ve çok kademeli kompresör, ara soğutucular, üç seviyeli depolama tankları ile dispenser birimi ayrıntılı biçimde temsil edilmiştir. Model, araç dolum süreci boyunca sıcaklık, basınç ve debi değişimlerinin zamana bağlı olarak izlenmesini sağlamaktadır. Araç tankı, hortum ve depo bileşenleri arasındaki akış ve ısı transferi ilişkileri incelenmiş; farklı gaz özellikleri, ortam koşulları ve dolum senaryoları karşılaştırmalı olarak analiz edilmiştir. Sistem performansı üzerindeki etkisi nedeniyle kademeli depolama sistemine ait hem basınçların hem tank hacim oranlarının optimizasyonu gerçekleştirilmiş; bu kapsamda Taguchi deneysel tasarımı uygulanmış ve çoklu performans kriterleri Gri İlişki Analizi (GRA) yöntemiyle birlikte değerlendirilmiştir. Geliştirilen model ve elde edilen optimizasyon çıktıları, CNG istasyonlarının tasarımı ve işletilmesi için uygulanabilir mühendislik kararları sunmakta, literatüre hem bilimsel hem de pratik katkılar sağlamaktadır.In this dissertation, the thermodynamic behavior of compressed natural gas (CNG) refueling stations, the dynamic interaction among system components, and the optimization of design parameters are analyzed through a multidisciplinary and integrated approach. Initially, thermodynamic properties such as specific volume, enthalpy, entropy, compressibility factor, and speed of sound were calculated depending on temperature and pressure for various natural gas mixtures. For validation purposes, the AGA8 DC92 equation of state was used, while the main modeling was carried out using the CoolProp library to enable more flexible and comprehensive calculations. The computed data were transferred into a physical model developed in the Simulink environment, which includes a compressor with multiple stages, intercoolers, a storage tank system with three pressure levels, and a dispenser unit. The model allows time-based monitoring of temperature, pressure, and mass flow variations during the vehicle filling process. The flow and heat transfer interactions between the vehicle tank, hose, and storage units were examined, and different gas compositions, environmental conditions, and filling scenarios were comparatively analyzed. Due to their significant impact on system performance, both reservoir pressures and volume ratios of the storage tanks were optimized. In this context, the Taguchi experimental design was applied, and multiple performance indicators were evaluated using the Grey Relational Analysis (GRA) method. The developed model and the resulting optimization outcomes provide practical engineering recommendations for improving the design and operation of CNG refueling systems and contribute original insights to the scientific literature