Browsing by Author "Kahraman, B"

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    The influence of coal bottom ash and tincal (boron mineral) additions on the physical and microstructures of ceramic bodies
    Bayca, SU; Batar, T; Sayin, E; Solak, O; Kahraman, B
    In this paper, the influence of coal bottom ash and tincal additions on the physical properties and microstructures of the standard wall tile body composition was investigated. Water absorption, fang strength, dry and fired shrinkage tests of the incorporated ceramic bodies and reference body were done. Microstructures of sintered tiles were analyzed using a scanning electron microscope (SEM). The results show that tincal additions to the ceramic body improved the physical properties of the tiles. As a result, tincal can be used as a flux material in the ceramic bodies due to its favorable effects on the water absorption and fired strength. The results revealed that bottom ash can be used in the ceramic tile body composition. When bottom ash was used in the ceramic industry, environmental hazards of bottom ash are inhibited. Furthermore, bottom ash is transformed to an economic product.
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    The performance prediction of roadheaders with response surface analysis for underground metal mine
    Özfirat, KM; Malli, T; Özfirat, PM; Kahraman, B
    Roadheaders are being used in development roads in underground mines. Especially, as total reserve is enough for large investments and mine roads, roadheaders are important to increase production rate. Roadheaders are classified according to the weight head drive or total power. In this study, the effects of several factors on roadheader performance is examined. The factors examined are power of the machine, weight of the machine, ratio of power to weight, drilling rate index, uniaxial compressive strength and rock mass rating. Instantaneous cutting ratio is used to define the performance of the machine. Response surface methodology and linear regression are used to investigate the relations between these variables. In the results of the study, machine performance is found to be highly correlated with machine power (P), weight (W) and the P/W ratio of the machine.
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    Integration of fuzzy analytic hierarchy process and multi-objective fuzzy goal programming for selection problems: An application on roadheader selection
    Ozfirat, PM; Ozfirat, MK; Malli, T; Kahraman, B
    In this study a general methodology employing fuzzy analytic hierarchy process and fuzzy goal programming is developed for selection problems. The proposed methodology has two main sub-phases. In the first phase, fuzzy triangular numbers are used in order to represent the comparisons among decision criteria. Then lower and upper bounds as well as mid-values of priorities belonging to each decision criteria are computed. In the second phase these values and fuzzy triangular numbers are entered into the goal programming model and the model is solved to give the final priorities of decision criteria. Then the weighted sum of ratings for each selection alternative are found where the weights are final priorities from goal programming model. The proposed methodology is presented on a real life roadheader selection problem from mining industry. The results revealed that the methodology is easily applicable and provides satisfactory results.
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    Role of Proopiomelanocortin in Preventing Miscarriage
    Ozbilgin, K; Kahraman, B; Atay, C; Vatansever, S; Uluer, ET; Özçakir, T
    OBJECTIVE: To compare the distribution of proopiomelanocortin (POMC) in decidua and placenta samples from missed abortion and voluntary termination cases in order to research the effects in the etiology of missed abortion. STUDY DESIGN: Decidual materials were collected from patients who were diagnosed with missed abortion (n=19) and legal voluntary termination cases (n=15) under 10 gestational weeks. Materials were divided into 2 groups for examination. For all samples, POMC primary antibody was performed by immunohistochemical staining. The number of stained cells was calculated by using the H-score technique. RESULTS: In the missed abortion group the mean age was 28.7 (18-41), and in the control group the mean age was 27.5 (21-37). POMC immunoreactivity was determined to be lower in the parenchyma and placenta of the missed abortion group than those of the control group. POMC immunoreactivities were found to be higher in both the syncytiotrophoblast and cytotrophoblast cells of the missed abortion group than those of the control group (p <0.005). CONCLUSION: POMC polypeptide precursor and process. Local production has become a paradigmatic has a role in the partiirition of POMC in placenta and decidua may influence pregnancy and may have a role in missed abortion pathogenesis.
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    The expression of Forkhead transcription factors in decidua and placenta in patients with missed abortion
    Ozbilgin, K; Kahraman, B; Turan, A; Atay, C; Vatansever, S; Inan, S; Özçakir, T
    Background: Forkhead transcription factors 3a (FOXO3a) has pleiotropic biological functions in the female reproductive tract. FOXO3a has a function in decidualization, in placental development, and also in inhibition of apoptosis. This study aims to investigate a possible role of FOXO3a in missed abortion. Materials and Methods: Decidual and placental tissue samples were obtained from the women with unwanted pregnancy as the control group and with missed abortion as the patient group. Immunohistochemistry technique was utilized to compare FOXO3a expression of the decidual cells in uterine decidual stroma and cytotrophoblast-syncytiotrophoblast cells in placental villous stroma. Immunohistochemistry was evaluated semi-quantitatively utilizing the H-score technique. Results: It was demonstrated that H-Scores of FOXO3a expression in both uterine decidual stroma were increased in the missed abortion group (255.83 +/- 12.41) than in the normal pregnancy group (133.33 +/- 17.43). It was also shown that there was no difference between non-decidual area of the endometrium of the normal pregnancy and the missed abortion group (30.33 +/- 4.32; 39.66 +/- 14.30, respectively) and placental villous stroma (13.00 +/- 1.89; 13.00 +/- 1.67, respectively). However, the immunoreactivity of cytotrophoblast and syncytiotrophoblast cells significantly increased in the missed abortion group (18.83 +/- 1.47; 322.00 +/- 6.06, respectively) than in the normal pregnancy group (11.00 +/- 1.26; 254.00 +/- 8.17, respectively) (p < 0.05). Conclusion: These data support the hypothesis that increased FOXO3a expression in missed abortion may prevent the discharge of dead fetus to maintain decidualization, prevention of oxidative stress, immunomodulation, and inhibition of apoptosis.
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    Distribution of Furin, TNF-α, and TGF-β2 in the Endometrium of Missed Abortion and Voluntary First Trimester Termination Cases
    Ozbilgin, K; Turan, A; Kahraman, B; Atay, C; Vatansever, S; Uluer, ET; Özçakir, T
    OBJECTIVE: To identify the role of furin, TNF-alpha, and TGF-beta 2 in human missed abortion pathogenesis. STUDY DESIGN: Decidual materials were collected from patients diagnosed with a missed abortion (n=10) (missed abortion group) and from legal voluntary termination cases at <10 gestational weeks (n=10) (normal pregnancy group). Tissue samples were collected from each group by dilation and curettage under mask anesthesia. For all tissue samples, furin, TNF-alpha, and TGF-beta 2 primary antibodies were performed by immunohistochemical staining. The number of stained cells was evaluated by using the H-score technique. RESULTS: In immunohistochemical examination, the immunoreactivities of furin, TNF-alpha, and TGF-beta 2 were found to be higher in syncytiotrophoblastic cells in the missed abortion group than in the normal pregnancy group (p < 0.005). Additionally, high immunoreactivity of TNF-alpha and TGF-beta 2 molecules was established only in cytotrophoblastic cells of missed abortions (p <0.005) in examination at decidual cells of the missed abortion group; furin immunoreactivities were detected higher in the missed abortion group than in the control group, but TNF-alpha and TGF-beta 2 immunoreactivity were increased in number in the normal pregnancy group (p < 0.005). CONCLUSION: It is considered that high levels of furin and the 2 furin-related proteins (TNF-alpha and TGF-beta 2), which play important roles in proliferation, invasion, migration, differentiation, and survival of cells, may be the reason of proceeding decidualization, placentation, and prevention from abortion, in spite of terminating the fetal life.
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    Relationship between functional status and fatigue after COVID-19 infection: a multicenter study from Turkiye
    Candemir, I; Ergün, P; Kaymaz, D; Sahin, ME; Özmen, I; Yildirim, E; Dilektasli, AG; Yigitliler, B; Odabas, A; Kizilirmak, D; Sari, S; Korkmaz, C; Tasci, C; Arslan, Y; Savci, S; Kahraman, B; Tanriverdi, A; Sevinç, C; Saglam, M; Ince, DI; Yagli, NV; Kütükcü, E; Durmaz, D; Durutürk, N; Ulubay, G; Kiliç, L; Çaglayan, B; Moray, A; Olcay, SS; Özkaya, G
    Background/aim: Symptoms of COVID-19 may persist for months. One of the persistent symptoms of COVID-19 is fatigue, which reduces functional status. The relationship between fatigue, functional status, and various other factors has received little attention, which this study aims to address.. Materials and methods: Patients with COVID-19 infection were included in this multicenter cross-sectional study. Age, sex, body mass index (BMI), marital status, smoking status, presence and duration of chronic disease, comorbidity index, regular exercise habits, time since COVID-19 diagnosis, hospitalization status, length of hospital stay, intubation status, home oxygen therapy after discharge, participation in a pulmonary rehabilitation program, presence of dyspnea, presence of cough, presence of sputum, and modified Medical Research Council, Post-COVID Functional Status (PCFS), Fatigue Severity Scale (FSS), and EQ-5D-5L Questionnaire scores were recorded. Results: We enrolled 1095 patients, including 603 (55%) men and 492 (45%) women with a mean age of 50 +/- 14 years. The most common chronic lung disease was COPD (11%) and 266 (29%) patients had nonpulmonary disease. The median time elapsed since COVID-19 diagnosis was 5 months; the hospitalization rate was 47%. The median PCFS grade was 1 (0-4) and the median FSS score was 4.4 (1-7). The PCFS and FSS were positively correlated (r = 0.49, p < 0.01; OR: 1.88, 95% CI: 1.68-2.10). Both functional status and fatigue were associated with quality of life, which was lower in older patients, those with higher BMI, those with systemic disease, those not exercising regularly, and those with more severe COVID-19 infection (defined by dyspnea, pneumonia as indicated by computed tomography, hospitalization, length of stay, ICU admission, intubation, and the need for home oxygen after discharge). Conclusion: Fatigue may cause poorer functional status regardless of the time since COVID-19 diagnosis. In this study, patients with FSS scores of >4.78 showed moderate to severe functional limitations. It is important to address modifiable patient risk factors and reduce the severity of COVID-19 infection.
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    The Relationship Between Functional Status and Fatigue After COVID-19 Infection
    Candemir, IÇ; Ergun, P; Kaymaz, D; Özmen,; Yildirim, E; Dilektasli, AG; Yigitler, B; Kizilirmak, D; Sari, S; Korkmaz, C; Tasçi, C; Arslan, Y; Savci, S; Kahraman, B; Tanriverdi, A; Sevinç, C; Saglam, M; Ince, DI; Yagli, NV; Kütükçü, E; Durmaz, D; Durutürk, N; Ulubay, G; Kiliç, L; Çaglar, B; Moray, A; Olcay, SS
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    Evaluation of abdominal computed tomography findings in patients with COVID-19: a multicenter study
    Onur, MR; Özbay, Y; Idilman, I; Karaosmanoglu, AD; Ramadan, SU; Barlik, F; Aydin, S; Odaman, H; Altay, C; Akin, IB; Dicle, O; Appak, O; Gülpinar, B; Erden, A; Kula, S; Çoruh, AG; Öz, DK; Kul, M; Uzun, C; Karavas, E; Levent, A; Artas, H; Eryesil, H; Solmaz, O; Kaygusuz, TO; Farasat, M; Kale, AB; Düzgün, F; Pekindil, G; Apaydin, FD; Duce, MN; Balci, Y; Esen, K; Kahraman, AS; Karaca, L; Özdemir, ZM; Kahraman, B; Tosun, M; Nural, MS; Camlidag, I; Onar, MA; Balli, K; Güler, E; Harman, M; Elmas, NZ; Öztürk, C; Güngör, O; Herek, D; Yagci, AB; Erol, C; Seker, M; Islek, I; Can, Y; Aslan, S; Bilgili, MYK; Göncüoglu, A; Keles, H; Sarikaya, PZB; Bakir, B; Kartal, MGD; Durak, G; Oguzdogan, GY; Alper, F; Yalçin, A; Gürel, S; Alan, B; Gündogdu, E; Aydin, N; Cansu, A; Kus, CC; Tuncer, EO; Piskin, FC; Er, HC; Degirmenci, B; Özmen, MN; Kantarci, M; Karçaaltincaba, M
    PURPOSETo evaluate the frequency of abdominal computed tomography (CT) findings in patients with coronavirus disease-2019 (COVID-19) and interrogate the relationship between abdominal CT findings and patient demographic features, clinical findings, and laboratory test results as well as the CT atheroscle-rosis score in the abdominal aorta.METHODSThis study was designed as a multicenter retrospective study. The abdominal CT findings of 1.181 patients with positive abdominal symptoms from 26 tertiary medical centers with a positive polymerase chain-reaction test for severe acute respiratory syndrome coronavirus 2 were reviewed. The frequency of ischemic and non-ischemic CT findings as well as the association between CT findings, clinical features, and abdominal aortic calcific atherosclerosis score (AA-CAS) were recorded.RESULTSIschemic and non-ischemic abdominal CT findings were detected in 240 (20.3%) and 328 (27.7%) patients, respectively. In 147 patients (12.4%), intra-ab-dominal malignancy was present. The most frequent ischemic abdominal CT findings were bowel wall thickening (n = 120; 10.2%) and perivascular infil-tration (n = 40; 3.4%). As for non-ischemic findings, colitis (n = 91; 7.7%) and small bowel inflammation (n = 73; 6.2%) constituted the most frequent disease processes. The duration of hospital stay was found to be higher in patients with abdominal CT findings than in patients without any positive findings (13.8 & PLUSMN; 13 vs. 10.4 & PLUSMN; 12.8 days, P < 0.001). The frequency of abdominal CT findings was significantly higher in patients who did not survive the infection than in patients who were discharged after recovery (41.7% vs. 27.4%, P < 0.001). Increased AA-CAS was found to be associated with a higher risk of ischemic conditions in abdominal CT examinations.CONCLUSIONAbdominal symptoms in patients with COVID-19 are usually associated with positive CT findings. The presence of ischemic findings on CT correlates with poor COVID-19 outcomes. A high AA-CAS is associated with abdominal ischemic findings in patients with COVID-19.