Başkent Üniversitesi Kurumsal Akademik Arşivi
Başkent Üniversitesi DSpace, üniversitemiz tarafından doğrudan veya dolaylı olarak yayınlanan kitap, makale, tez, bildiri, rapor ve araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar. Bu sistem, üniversitemizin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve yayınların etkisini artırmak amacıyla telif haklarına uygun olarak Açık Erişim imkanı sağlar.
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Comparison of Helical and TomoDirect Techniques with Simultaneous Integrated Boost in Early Breast Cancer Patients
(REPORTS OF PRACTICAL ONCOLOGY AND RADIOTHERAPY, 2023) Onal, Cem; Bozca, Recep; Oymak, Ezgi; Guler, Ozan Cem
Background: The aim of the study was to perform dosimetric comparisons of helical (H) and TomoDirect (TD) plans for whole-breast irradiation (WBI) with simultaneous integrated boost (SIB) in early-stage breast cancer patients undergoing breast conserving surgery.Materials and methods: Fifty patients, 25 with left-side and 25 with right-side tumors, were determined for a treatment planning system for a total dose of 50.4Gy in 1.8Gy per fraction to WBI, with a SIB of 2.3Gy per fraction delivered to the tumor bed. The planning target volume (PTV) doses and the conformity (CI) and homogeneity indices (HI) for PTV(breast )and PTVboost, as well as organ-at-risk (OAR) doses and treatment times, were compared between the H and TD plans.Results: All plans met the PTV coverage criteria for the H plan, except for mean V107 of PTVbreast for TD plan. The H plan yielded better homogeneity and conformity of dose distribution compared to the TD plan. The ipsilateral mean lung doses were not significantly different between the two plans. The TD plans is advantageous for mean doses to the heart, contralateral breast and lung, spinal cord, and esophagus than the H plans. In both the H and TD plans, the right-sided breast patients had lower heart dose parameters than the left-sided breast patients. The TD plan is superior to the H plan in sparing the contralateral breast and lung by decreasing low-dose volumes.Conclusions: While the OAR dose advantages of TD are appealing, shorter treatment times or improved dose homogeneity and conformity for target volume may be advantageous for H plan.
Causal Effect of Obesity on the Probability of Employment in Women in Turkey
(ECONOMICS & HUMAN BIOLOGY, 2023) Pekkurnaz, Didem
This study aims to investigate the causal effect of obesity on the employment probability of women in Turkey via the instrumental variable approach by using data from the 2018 Turkey and Demographic Health Survey. Obesity prevalence in the area of living and the overweight status of the oldest child, which are the most common types of instruments seen in the literature, are used as instruments. Consistent with the OLS result, the 2SLS estimate indicates that obese women are statistically significantly less likely to be employed when the overweight status of the child is used as an instrument. On the other hand, the statistically significant effect of obesity disappears when the area level obesity prevalence is used as the instrument. In addition, obesity in women decreases the likelihood of employment in the services sector and full-time jobs and employment with social security. Although the results of this study do not indicate the source of the effect found, the presence of a causal relationship for women should not be ignored when the economic burden of obesity for Turkey is considered.
Clear Cell Carcinoma of the Uterine Cervix; An Unusual HPV-Independent Tumor: Clinicopathological Features, PD-L1 Expression, and Mismatch Repair Protein Deficiency Status of 16 Cases
(TURKISH JOURNAL OF OBSTETRICS AND GYNECOLOGY, 2023) Bulutay, Pinar; Eren, Ozgur Can; Ozen, Ozlem; Haberal, Asuman Nihan; Kapucuoglu, Nilgun
Objective: Endocervical clear cell carcinoma (c-CCC) is a rare and HPV-independent adenocarcinoma type of cervix. Being usually resistant to conventional chemotherapy. Immunotherapy has recently been added as a preferred regimen as a second-line treatment option for programed cell death-ligand 1 (PD L1)-positive or mismatch repair (MMR) deficient cervical carcinomas. In this study, clinicopathological features, PD-L1 expression, and MMR deficiency status of c-CCCs were investigated.
Materials and Methods: Sixteen c-CCC diagnosed cases were included in this study. PD-L1 expression was evaluated using two different PD-L1 clones (22C3 and SP263). MMR deficiency status of the cases was evaluated using four MMR proteins (MLH1, PMS2, MSH2, and MSH6).
Results: Most of the c-CCC cases were presented as FIGO Stage I (68.75%). PD-L1 expression in either tumoral or tumor-infiltrating immune cells (TILs) was present in 62.5% (10/16) and 69% (11/16) of the 22C3 and SP263 clones, respectively. Most of the cases with high TIL density were also positive for PD-L1. The PD-L1 expression rate was less than 50% in most of the cases and 12.5% of the cases shared extensive PD-L1 staining. Overall, MMR deficiency was observed in 31.25% of the cases. Most of the MMR-deficient cases (80%) were PD-L1 positive.
Conclusion: Although our study cohort is limited, we have shown that PD-L1 expression and MMR deficiency can be found in c-CCCs in variable degrees. These findings suggest that accompanying TIL density and MMR deficiency could be used as candidates for predicting PD-L1 positivity for c-CCCs. However, to indicate the clinical importance of these findings, objective treatment outcomes of cases treated with immunotherapy should be seen.
Characteristics and Outcomes of Myelodysplastic Syndrome Patients Treated With Darbepoetin Alfa for Anemia in Turkey: A Multicenter Retrospective Study
(CLINICAL LYMPHOMA MYELOMA & LEUKEMIA, 2023) Acar, Ibrahim Halil; Atalay, Figen; Demirsoy, Esra Terzi; Can, Ferda; Guven, Zeynep Tugba; Cetiner, Mustafa; Tombak, Anil; Comert, Melda; Guvenc, Birol
A Hybrid Monte Carlo Simulation Risk Model for Oil Exploration Projects
(MARINE POLLUTION BULLETIN, 2023) Balas, Egemen Ander
A new 3-D Hybrid Monte Carlo Simulation (MCS) Risk Model is proposed in this study. The wind, wave, current, climate change, and tsunami sub-models of the Three-Dimensional Hydrodynamic Transport and Water Quality Model HYDROTAM-3D are interrelated with MCS, to obtain probability distributions for the simulation of environmental conditions. This is the only model that can incorporate the tsunami, storm, and sea level rise risks in oil exploration projects. The spill risk index (SRI) of 50 blue barrels spilled due to a blowout from the rig/port during fuel supply was circa 1 ton/ship as Tier I with an average annual occurrence probability of 1.0 x 10-6. The discharge of 4000 bbls for 6 h was modeled, resulting in the SRI of 546 metric tons from the riser blowout with SRI = 0.2 per meter, indicating a Tier II risk. The mean arrival time of this spill was found by MCS as 145 min.