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
Investigation of the relationship between cancer and the homologous recombination repair (HRR) mechanism
(Acıbadem University, 2026) İntaş, Adar; Muslubaş, Berke; Yılmazer Aktar, Berin; Aysan, Arzu; Aksu, Soner
Background/Aim: A strong correlation exists between Double-strand breaks (DSBs), genomic instability, and cancer development. Homologous Recombination Repair (HRR) is the primary repair mechanism for highly accurate DSB repair. This study aimed to investigate the relationship between cancer and selected 12 genes involved in the HRR mechanism. Materials and Methods: Using the RT-qPCR analysis differences in the expression levels of the Ataxia Telangiectasia Mutated (ATM), BRCA1 Interacting Protein C-Terminal Helicase 1 (BRIP1), Fanconi Anemia Complementation Group D2 (FANCD2), Tumor Protein p53 Binding Protein 1 (TP53BP1), DNA Polymerase Theta (POLQ), RAD54 Like (RAD54L), AT-Rich Interaction Domain 1A (ARID1A), RAD52 DNA Repair Protein (RAD52), Bloom Syndrome Protein (BLM), SWI/SNF-Related Matrix-Associated Actin-Dependent Regulator of Chromatin Subfamily A Containing DEAD/H Box 1 (SMARCAD1), Werner Syndrome ATPDependent, Helicase (WRN) and RecQ Like Helicase 4 (RECQL4) genes between cancer and normal cell lines were investigated. Frequently used 10 cancer and 2 normal cell lines were used in this study. Results: It was determined that RAD52 was significantly up-regulated only in colon cancer cell lines. ARID1A was significantly down-regulated, particularly in breast and lung cancer. BLM, WRN, TP53BP1, ATM and RAD54L were down-regulated in all cancer types. RECQL4 was down-regulated in breast and lung cancer, but up-regulated in liver and brain cancer. BRIP1 was down-regulated in breast, brain, and lung cancer, but up-regulated in liver and colon cancer cell lines. FANCD2 was up-regulated only in lung cancer, and significantly down-regulated in all other cancer types. POLQ was significantly down regulated especially in lung cancer. Conclusion: This study has provided preliminary results suggesting that the expression differences observed in the interested genes could be used as a molecular indicator for the carcinogenesis. Meaningful results have also been obtained indicating that diagnostic panels based on gene expression levels can be developed for monitoring cancer progression.
Knowledge and practices of students receiving cooking education about food safety: The example of Istanbul province
(İstanbul Aydın Üniversitesi, 2026) Mutlu, Hayrettin; Tokay, Murat Mutlu; Ercan Karakaya, Zeynep
Nutrition is the most basic need for a healthy life. Healthy food consumption depends on ensuring food safety. Food safety encompasses processes that protect food from physical, biological, and chemical hazards and prevent loss of nutritional value at all stages, from production to the table. In this cross-sectional study, a face-to-face survey was administered to 348 students (male: 183; female: 165) enrolled in three high schools of tourism and hotel management in Istanbul. The overall knowledge level about food safety was higher among female students (14.553.44) than among male students (13.57±3.55) (p < <0.05). The total food safety knowledge level scores for the classes were 13.37±3.50, 14.64±3.60, and 14.22±3.70 in the 10th, 11th, and 12th grades, respectively. A significant increase was detected from the 10th to the 11th grade, whereas the 12th-grade scores remained comparable to those of the 11th grade (p<0.05). The results indicate the need to expand and sustain food safety education. In conclusion, the findings demonstrate that food safety education is a crucial tool for supporting access to healthy, safe food.
A comprehensive evaluation of the relationships between craniofacial features, oral behaviors, respiratory pattern, sleep, and posture in adolescents
(İstanbul Sağlık ve Teknoloji Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2026) Yıldız, Saliha Yağmur
This study was conducted to comprehensively evaluate the relationships between craniofacial features, oral behaviors, respiratory pattern, sleep and posture in adolescents aged 12–17 years. A total of 180 adolescents in the permanent dentition stage with orthodontic treatment needs were included in the study. Clinical assessments included occlusion, orofacial structures, and upper airway-related findings. Parafunctional habits were evaluated using the Oral Behaviors Checklist. Respiratory capacity was assessed by Peak Nasal Inspiratory Flow (PNIF) and oxygen saturation (SpO₂) measurements. Sleep quality was evaluated using the Children's Sleep Habits Questionnaire (CSHQ) and posture was assessed with the New York Posture Scale (NYPS). Statistical significance was set at p<0.05. Individuals with a tendency toward mouth breathing exhibited significantly lower nasal airflow, reduced oxygen saturation, and higher sleep-related symptom scores (all p<0.001). Additionally, significant differences were identified among malocclusion classes in terms of oral behaviors, respiratory parameters, oxygenation changes, sleep findings, and posture (p<0.05). Multivariable analyses revealed that mouth-breathing tendency was independently associated with increased oral behaviors, lower PNIF and SpO₂ values, and higher CSHQ total scores. Among the malocclusion classes, the Class III group was found to be associated with an increased number of oral behaviors and lower PNIF values in some models. The findings indicate that there are significant interrelated associations among malocclusion, parafunctional habits, respiratory parameters, sleep, and posture, particularly in relation to mouth-breathing tendency. These results support the importance of evaluating airway, sleep, oral behaviors, and posture together in clinical assessments.
CFD analysis of counterflow channel type heat exchangers
(Liberty Publishing House, 2026) Şimşek Uzun, Sevda; Tanrıver, Kürşat; Aydın, Diyar Can; Koçyiğit, Ümit Muhammet; Romanello Bueno, Jose Geraldo
Heat exchangers are important engineering systems. They have a key role in energy recovery and improving process efficiency. Counter-flow heat exchangers give better heat transfer because they keep a higher temperature difference between the two fluids. However, there are still only a few studies that examine the effects of inlet temperatures and flow velocities together. This makes it difficult to find the best operating conditions and improve the design. In this study, the thermal performance of a counter-flow channel heat exchanger was studied by using Computational Fluid Dynamics (CFD). The main aim of this study is to examine the hot fluid velocity, cold fluid velocity, and inlet temperature difference together. The effects of these three parameters on heat transfer performance were compared in one parametric study. A three-dimensional model was created in ANSYS Fluent. All simulations were carried out under laminar flow conditions. Different operating cases were compared to determine the main factors affecting the hot fluid outlet temperature. The results showed that when the hot fluid inlet velocity increased from 0.07 m/s to 9.6 m/s, the hot fluid outlet temperature increased from 283.18 K to 326.58 K. The cold fluid outlet temperature also increased from 277.43 K to 283.17 K. On the other hand, increasing the cold fluid velocity decreased the outlet temperatures of both fluids. In addition, when the inlet temperature difference increased from 65 K to 90 K, the hot fluid outlet temperature increased from 310.56 K to 323.55 K, and the cold fluid outlet temperature increased from 281.32 K to 283.45 K. The temperature distribution also changed along the channel. This shows that these parameters have an important effect on heat transfer. The results show that the inlet conditions are very important for the thermal performance of counter flow heat exchangers. This study also shows that CFD is a useful and reliable tool for heat exchanger design. In the future, this work can be improved by using different geometries, turbulence models, and optimization methods.
Air ticket sales forecasting for B2B travel agencies
(Emerald Publishing, 2026) Uzun-Per, Meryem; Akkaya, Ümit Murat; Kalkan, Habil
Purpose – This study addresses the air ticket sales forecasting problem for business-to-business (B2B) travel agencies, a largely unexplored area compared to airlines and business-to-consumer agencies. To meet guarantee deposit requirements and manage financial risk exposure, B2B agencies require accurate demand estimation for budget planning and revenue management. The study proposes a hybrid deep learning forecasting model integrating recurrent neural network (RNN), long short-time memory (LSTM) and bidirectional long short-term memory (BiLSTM) architectures to capture both short-term fluctuations and long-term temporal dependencies in ticket sales data. Design/methodology/approach – Approximately eight years (from 3 August 2014 to 2 June 2022) of daily search and ticket sales data from a B2B travel consolidator agency were combined with external variables, including holidays, weather conditions, exchange rates, gross domestic product per capita and COVID-19 cases. Two datasets (with and without pandemic data) were constructed. After preprocessing and Random Forest feature selection, seasonal autoregressive integrated moving average (SARIMA), Prophet, RNN, LSTM and BiLSTM models were implemented and compared with the proposed hybrid architecture using a sliding window forecasting framework. Performance was evaluated using mean absolute percentage error (MAPE) and root mean squared error (RMSE). Findings – The proposed hybrid model achieved the highest forecasting accuracy across both datasets, outperforming statistical and individual deep learning models. It obtained MAPE values of 5.83% and 6.16% and RMSE values of 0.0379 and 0.0411, respectively. BiLSTM ranked as the second-best method, while SARIMA and Prophet showed substantially lower accuracy. Results also indicated that excluding pandemic variables did not significantly reduce predictive performance, but still, pandemic-related volatility increased the error rate of most of the methods and increased forecasting difficulty. Originality/value – This research is the first to examine ticket sales forecasting specifically for B2B travel agencies. It introduces a novel hybrid sequential deep learning architecture and evaluates the role of pandemic and macroeconomic variables in forecasting performance. The findings demonstrate the effectiveness of hybrid recurrent models for complex real-world demand forecasting problems.
