Browsing by Author "Yildiz, A"

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    Exergetic performance assessment of solar photovoltaic cell (PV) assisted earth to air heat exchanger (EAHE) system for solar greenhouse cooling
    Yildiz, A; Ozgener, O; Ozgener, L
    An experimental system was developed and tested in order to investigate the exergetic performance of a solar photovoltaic system (PV) assisted earth-to-air heat exchanger (under ground air tunnel) that is used for greenhouse cooling at the Solar Energy Institute, Ege University, Izmir, Turkey. This system was under operational conditions successfully during the 2010 summer cooling season. This paper provides the experimental results obtained between 18th of August and 26th of August of in 2010. Exergy destruction in the system was calculated and presented in this paper using a reference temperature of 15 degrees C. Results are discussed and interpreted in the paper for various performance metrics, such as the effect of climatic conditions and operating conditions on the system performance. Results show that the system may be satisfactorily used for greenhouse cooling in the Mediterranean and Aegean regions of Turkey. (C) 2011 Elsevier B.V. All rights reserved.
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    G protein β3 subunit gene polymorphism in Turkish hypertensives
    Alioglu, E; Ercan, E; Tengiz, I; Yildiz, A; Türk, UO; Saygi, S; Çam, FS; Berdeli, A
    Objective: G protein is one of the most important regulators of intracellular signaling pathways. C825T polymorphism of G protein (33 subunit is associated with increased intracellular signal transduction. The 825T allele has been found associated with a variety of cardiovascular risk factors, including hypertension. The aim of the present study was to investigate the association between the C825T polymorphism of the G protein beta 3 subunit and essential hypertension in Turkish population. Methods: This cross-sectional, case-controlled study included 209 patients with essential hypertension (Patient group) and 82 subjects with normal blood pressure (Control group). The G protein 133 subunit C825T gene polymorphism was determined by polymerase chain reaction. Hypertension was defined according to JNC VII criteria. Statistical analysis was performed using Chi square and unpaired t tests. Logistic regression analysis was used to study association between hypertension and genotypes. Results: We found that the frequencies of the G protein 133 subunit C825T polymorphism in hypertensive and control groups were 17.7%, 59.3%, 23.0% and 32.9%, 48.8%, 18.3%, (CC, CT, TT) respectively (chi(2)=7.963, p=0.019). In the multivariate logistic regression analysis CT genotype had 2.2 (OR=2.262, 95% CI 1.228-4.167, p=0.009), and TT genotype had 2.3 times (OR=2.335, 95% CI 1.089-5.008, p=0.029) greater risk of hypertension compared to CC genotype. Conclusion: It seems that the G protein (33 subunit C825T gene polymorphism is associated with systolic and diastolic blood pressure. Furthermore, the study indicates that the G protein 133 subunit may be a susceptible gene to essential hypertension. (Anadolu Kardiyol Derg 2008; 8: 337-5)
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    Predictive factors for the development of brain metastases in patients with malignant melanoma: a study by the Anatolian society of medical oncology
    Gumusay, O; Coskun, U; Akman, T; Ekinci, AS; Kocar, M; Erceleb, ÖB; Yazici, O; Kaplan, MA; Berk, V; Cetin, B; Taskoylu, BY; Yildiz, A; Goksel, G; Alacacioglu, A; Demirci, U; Algin, E; Uysal, M; Oztop, I; Oksuzoglu, B; Dane, F; Gumus, M; Buyukberber, S
    The development of brain metastases (BMs) was associated with poor prognosis in melanoma patients. Patients with BMs have a median survival of < 6 months. Melanoma is the third most common tumor to metastasize to the brain with a reported incidence of 10-40 %. Our aim was to identify factors predicting development of BMs and survival. We performed a retrospective analysis of 470 melanoma patients between 2000 and 2012. The logistic regression analyses were used to identify the clinicopathological features of primary melanoma that are predictive of BMs development and survival after a diagnosis of brain metastases. There were 52 patients (11.1 %) who developed melanoma BMs during the study period. The analysis of post-BMs with Kaplan-Meier curves has resulted in a median survival rate of 4.1 months (range 2.9-5.1 months). On logistic regression analysis site of the primary tumor on the head and neck (p = 0.002), primary tumor thickness (Breslow > 4 mm) (p = 0.008), ulceration (p = 0.007), and pathologically N2 and N3 diseases (p = 0.001) were found to be significantly associated with the development of BMs. In univariate analysis, tumor thickness and performance status had a significant influence on post-BMs survival. In multivariate analysis, these clinicopathologic factors were not remained as significant predictive factors. Our results revealed the importance of primary tumor characteristics associated with the development of BMs. Ulceration, primary tumor thickness, anatomic site, and pathologic a parts per thousand yenN2 disease were found to be significant predictors of BMs development.
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    Impact of previous SWL on ureterorenoscopy outcomes and optimal timing for ureterorenoscopy after SWL failure in proximal ureteral stones
    Irer, B; Sahin, MO; Erbatu, O; Yildiz, A; Ongun, S; Cinar, O; Cihan, A; Sahin, M; Sen, V; Ucer, O; Kizilay, F; Bozkurt, O
    Purpose We aimed to evaluate the impact of previous unsuccessful shock wave lithotripsy (SWL) therapy on ureterorenoscopy (URS) outcomes in proximal ureteral stones and to define whether there is any optimal timing for safe URS after SWL. Methods The patients who underwent URS for proximal ureteral stones between the years 2015 and 2018 in eight centers were included. Patients were divided into two groups according to previous SWL history; group 1 consisted of patients without SWL before URS for the stone [SWL (-)] and group 2 consisted of patients with a previous SWL for the stone [SWL (+)]. Demographics, operation outcomes and stone characteristics were compared between these two groups. Regarding the complication and success rates, optimal timing for URS after SWL for the stone was calculated with receiver operator characteristics curve analysis. Results Totally 638 patients were included (group 1: 466 patients and group 2: 172 patients). The operation and hospitalization times, rate of ureteral stenting and complications were significantly higher in group 2. Stone free status was similar between the groups. Optimal timing for URS after SWL was calculated as 16.5 days (AUC = 0.657, p = 0.012) with a sensitivity of 68% and specificity of 72%, regarding the complication rates. Complication rates were significantly higher in patients who were operated before 16.5 days (27.7% vs 6.5%, p < 0.001). Conclusions The optimal timing; 2-3 weeks delay of the URS procedure after unsuccessful SWL may decrease complication rates according to our results.
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    Predictive Factors of Ureterorenoscopy Outcomes in Proximal Ureteral Stones: A Multicenter Study of Aegean Study Group of the Society of Urological Surgery
    Sen, V; Irer, B; Erbatu, O; Yildiz, A; Ongun, S; Cinar, O; Cihan, A; Sahin, M; Sahin, MO; Ucer, O; Kizilay, F; Bozkurt, O
    Introduction: We aimed to evaluate the predictive factors in a holistic manner for ureterorenoscopy (URS) outcomes in proximal ureteral stones by a multicenter study. Materials and Methods: The data of patients who underwent URS for proximal ureteral stones between the years 2015 and 2018 in eight centers were recorded retrospectively. Patients were divided into two groups according to URS success: Group 1 consisted of patients with successful URS, and Group 2 consisted of patients with unsuccessful URS. The two groups were compared in terms of risk factors, stone, and clinical characteristics of patients. Results: A total of 638 patients were included in the study. Group 1 consisted of 527 (82.6%) patients, and Group 2 consisted of 111 (17.4%) patients. In multivariate logistic analysis, the key risk factors for URS success was found to be age (OR = 0.980, 95% [CI] = 0.963-0.996, p = 0.018), stone area (OR = 0.993, 95% [CI] = 0.989-0.997, p = 0.002), and operation time (OR = 0.981, 95% [CI] = 0.968-0.994, p = 0.005). Conclusions: To make the treatment decision of proximal ureteral stones, it is necessary to examine several parameters including available equipment, stone, and patient characteristics. Physicians should keep these risk factors in mind in the decision of treatment options.
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    Comparison of Efficacy and Complications of Holmium Laser and Pneumatic Lithotripters Used in the Ureterorenoscopic Treatment of Proximal Ureter Stones, a Multi-Center Study of Society of Urological Surgery Aegean Study Group
    Irer, B; Sen, V; Erbatu, O; Yildiz, A; Ongün, S; Çinar, Ö; Cihan, A; Sahin, M; Sahin, MO; Üçer, O; Kizilay, F; Bozkurt, O
    Objective:The aim of this study is to compare the efficacy and complications of holmium laser and pneumatic lithotripsy used in the ureterorenoscopic treatment of proximal ureteral stones. Materials and Methods: Data of 638 patients, who underwent ureterorenoscopy (URS) due to proximal ureteral stones in different centers, were obtained from patient files. The patients were divided into two groups according to the type of lithotripter used: group 1; laser lithotripter (n=324; 50.8%) and group 2; pneumatic lithotripter (n=314; 49.2%). URS was considered successful upon determination stone-free status with the imaging methods after treatment. The effectiveness and the complications of holmium:yttrium-aluminum-garnet laser and pneumatic lithotripsy were compared. Results: The total success rate of URS was 82.6% and the complication rate was 8.1%. The mean age of patients was similar between the groups; however, the body mass index values, stone surface area and stone Hounsfield unit were significantly higher in group 1. Although the mean operative time, complication rate and the mean length of hospital stay were similar between the groups; the URS success and postoperative ureteral J stent use rates were significantly higher in group 1 and the push-back rate was significantly higher in group 2. Conclusion: If laser lithotripsy is available in a clinic, we believe that it is better to use it as the first option in the treatment of proximal ureter stones. However, considering that it is not easy to access laser lithotripters due to their high cost in Turkey, pneumatic lithotripters may be an effective and inexpensive alternative that can also be safely used in these cases.
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    Comparison of the efficacy of sunitinib and pazopanib in patients with advanced non-clear renal cell carcinoma
    Yildirim, HC; Bayram, E; Chalabiyev, E; Majidova, N; Avci, T; Güzel, HG; Kapar, C; Uzun, M; Perkin, P; Akgül, F; Yildirim, SS; Sali, S; Yildiz, A; Kazaz, SN; Hendem, E; Arcagok, M; Tufan, G; Yildirim, U; Akgul, OF; Arslan, C; Taban, H; Sahin, E; Caglayan, M; Esen, R; Öksüzoglu, B; Guven, DC; Kaplan, MA; Araz, M; Basaran, M; Cubukcu, E; Gokmen, E; Cicin, I; Algin, E; Semiz, HS; Tural, D; Ozturk, B; Erdogan, AP; Sari, M; Kara, O; Erman, M
    Non-clear cell renal cell carcinoma (non-ccRCC) is a highly heterogeneous disease group, accounting for approximately 25% of all RCC cases. Due to its rarity and especially heterogeneity, phase III trial data is limited and treatment options generally follow those of clear cell RCC. In the literature, there exists a number of studies with sunitinib, cabozantinib, and everolimus, but data on the efficacy of pazopanib are limited. Our aim in this study was to compare the efficacy of pazopanib and sunitinib, in a multicenter retrospective cohort of non-ccRCC patients. Our study included patients diagnosed with non-ccRCC who received pazopanib or sunitinib treatment as first-line therapy from 22 tertiary hospitals. We compared the progression-free survival (PFS), overall survival (OS), and response rates of pazopanib and sunitinib treatments. Additionally, we investigated prognostic factors in non-ccRCC. PFS and response rates of sunitinib and pazopanib were found to be similar, while a numerical difference was observed in OS. Being 65 years and older, being in the intermediate or poor risk group according to the International Metastatic Renal Cell Carcinoma Database Consortium, having liver metastases, presence of a sarcomatoid component, and having de novo metastatic disease were found to be significantly associated with shorter PFS. Pazopanib treatment appears to have similar efficacy in the treatment of non-ccRCC compared to sunitinib. Though randomized controlled trials are lacking and will probably be never be available, we suggest that pazopanib could be a preferred agent like sunitinib and cabozantinib. Pazopanib and sunitinib treatments show similar progression free survival, overall survival and objective response rate.IMDC risk group, liver metastasis, sarcomatoid component and de novo metastatic disease were determined as prognostic factors