Buckling behavior of pultruded composite beams with circular cutouts

Mehmet Aktaş,H. Ersen Balcıoğlu 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.4

In this experimental and numerical study, the effect of plate thickness, the diameter of circular cutout, the distance between circular cutouts and rowing orientation angle effect (θ) on the buckling load of E-glass/vinylester pultruded composite beams with single and double circular cutouts, were investigated. The composite beam having 2, 4, and 6 mm thicknesses was produced as [Mat/θ/Mat/θ/Mat] by using pultrusion technique. Seven different fiber angles as 0°, 15°, 30°, 45°, 60°, 75°, and 90° were chosen for investigation of rowing orientation angle. The distances between each circular cutout were selected as 15, 30, 45, 60, and 75 mm in the case of double circular cutouts. The diameters of circular cutouts were chosen as 2, 4, 6, 8, and 10 mm to investigate the effect of cutout size. The experimental buckling loads were compared with the results calculated from the numerical analysis. ANSYS 11 commercial software was used for numerical study. A good agreement was obtained between numerical and experimental results.

Misoprostol alleviates paclitaxel-induced liver damage through its antioxidant and anti-apoptotic effects

Gür Fatih Mehmet,Aktaş İbrahim,Bilgiç Sedat,Pekince Merve 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.3

Backgrounds Anticancer drugs may damage non-target cells and tissues. One of the biggest reasons for changing or stopping chemotherapy regimens is these adverse effects. Objective This study aimed to investigate the therapeutic and protective efficacy of misoprostol (MP) against the harmful effects of paclitaxel (PAX), an anticancer drug, on normal liver tissue. Results Biochemical examinations revealed that activities of serum aspartate aminotransferase, alanine aminotransferase, and levels of triglyceride, and cholesterol and levels of tissue malondialdehyde increased significantly in the PAX group compared to the control group, and glutathione level decreased. The histological structure of the liver tissue of the control group rats was normal. Histopathological changes, such as focal microvesicular steatosis, sinusoidal dilatation, mononuclear cell infiltration, Councilman bodies, and an increase in apoptosis, were also observed in PAX group. The histopathological changes observed in the PAX group were greatly improved in the PAX + MP group. Conclusion When the obtained data were evaluated, it was concluded that the combined use of PAX with MP could reduce the cytotoxic effects of PAX on normal liver tissue, allowing cancer treatment to be continued uninterrupted and effectively.

Evaluation of Biochemical Recurrence-free Survival after Radical Prostatectomy by Cancer of the Prostate Risk Assessment Post-Surgical (CAPRA-S) Score

Aktas, Binhan Kagan,Ozden, Cuneyt,Bulut, Suleyman,Tagci, Suleyman,Erbay, Guven,Gokkaya, Cevdet Serkan,Baykam, Mehmet Murat,Memis, Ali Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Background: The cancer of the prostate risk assessment (CAPRA) score has been defined to predict prostate cancer recurrence based on the pre-clinical data, then pathological data have also been incorporated. Thus, CAPRA post-surgical (CAPRA-S) score has been developed based on six criteria (prostate specific antigen (PSA) at diagnosis, pathological Gleason score, and information on surgical margin, seminal vesicle invasion, extracapsular extension and lymph node involvement) for the prediction of post-surgical recurrences. In the present study, biochemical recurrence (BCR)-free probabilities after open retropubic radical prostatectomy (RP) were evaluated by the CAPRA-S scoring system and its three-risk level model. Materials and Methods: CAPRA-S scores (0-12) of our 240 radical prostatectomies performed between January 2000-May 2011 were calculated. Patients were distributed into CAPRA-S score groups and also into three-risk groups as low, intermediate and high. BCR-free probabilities were assessed and compared using Kaplan-Meier analysis and Cox proportional hazards regression. Ability of CAPRA-S in BCR detection was evaluated by concordance index (c-index). Results: BCR was present in 41 of total 240 patients (17.1%) and the mean follow-up time was $51.7{\pm}33.0$ months. Mean BCR-free survival time was 98.3 months (95% CI: 92.3-104.2). Of the patients in low, intermediate and high risk groups, 5.4%, 22.0% and 58.8% had BCR, respectively and the difference among the three groups was significant (P = 0.0001). C-indices of CAPRA-S score and three-risk groups for detecting BCR-free probabilities in 5-yr were 0.87 and 0.81, respectively. Conclusions: Both CAPRA-S score and its three-risk level model well predicted BCR after RP with high c-index levels in our center. Therefore, it is a clinically reliable post-operative risk stratifier and disease recurrence predictor for prostate cancer.

Prediction of behavior of fresh concrete exposed to vibration using artificial neural networks and regression model

Gultekin Aktas,Mehmet Sirac Ozerdem 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.4

This paper aims to develop models to accurately predict the behavior of fresh concrete exposed to vibration using artificial neural networks (ANNs) model and regression model (RM). For this purpose, behavior of a full scale precast concrete mold was investigated experimentally and numerically. Experiment was performed under vibration with the use of a computer-based data acquisition system. Transducers were used to measure time-dependent lateral displacements at some points on mold while both mold is empty and full of fresh concrete. Modeling of empty and full mold was made using both ANNs and RM. For the modeling of ANNs: Experimental data were divided randomly into two parts. One of them was used for training of the ANNs and the remaining part was used for testing the ANNs. For the modeling of RM: Sinusoidal regression model equation was determined and the predicted data was compared with measured data. Finally, both models were compared with each other. The comparisons of both models show that the measured and testing results are compatible. Regression analysis is a traditional method that can be used for modeling with simple methods. However, this study also showed that ANN modeling can be used as an alternative method for behavior of fresh concrete exposed to vibration in precast concrete structures.

Displacement prediction of precast concrete under vibration using artificial neural networks

Gultekin Aktas,Mehmet Sirac Ozerdem 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.4

This paper intends to progress models to accurately estimate the behavior of fresh concrete under vibration using artificial neural networks (ANNs). To this end, behavior of a full scale precast concrete mold was investigated numerically. Experimental study was carried out under vibration with the use of a computer-based data acquisition system. In this study measurements were taken at three points using two vibrators. Transducers were used to measure time-dependent lateral displacements at these points on mold while both mold is empty and full of fresh concrete. Modeling of empty and full mold was made using ANNs. Benefiting ANNs used in this study for modeling fresh concrete, mold design can be performed. For the modeling of ANNs: Experimental data were divided randomly into two parts such as training set and testing set. Training set was used for ANN’s learning stage. And the remaining part was used for testing the ANNs. Finally, ANN modeling was compared with measured data. The comparisons show that the experimental data and ANN results are compatible.

Mobile Web Service Architecture Using Context-store

( Sangyoon Oh ),( Mehmet Aktas ),( Geoffrey C. Fox ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.5

Web Services allow a user to integrate applications from different platforms and languages. Since mobile applications often run on heterogeneous platforms and conditions, Web Service becomes a popular solution for integrating with server applications. However, because of its verbosity, XML based SOAP messaging gives the possible overhead to the less powerful mobile devices. Based on the mobile client`s behavior that it usually exchanges messages with Web Service continuously in a session, we design the Handheld Flexible Representation architecture. Our proposed architecture consists of three main components: optimizing message representation by using a data format language (Simple_DFDL), streaming communication channel to reduce latency and the Context-store to store context information of a session as well as redundant parts of the messages. In this paper, we focus on the Context-store and describe the architecture with the Context-store for improving the performance of mobile Web Service messaging. We verify our approach by conducting various evaluations and investigate the performance and scalability of the proposed architecture. The empirical results show that we save 40% of transit time between a client and a service by reducing the message size. In contrast to solutions for a single problem such as the compression or binarization, our architecture addresses the problem at a system level. Thus, by using the Context-store, we expect reliable recovery from the fault condition and enhancing interoperability as well as improving the messaging performance.

Metabolic Syndrome Prevalence in Renal Cell Cancer Patients

Bulut, Suleyman,Aktas, Binhan Kagan,Erkmen, Akif Ersoy,Ozden, Cuneyt,Gokkaya, Cevdet Serkan,Baykam, Mehmet Murat,Memis, Ali Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Purpose: Renal cell carcinoma (RCC) is increasingly being recognized as a metabolic disease in recent studies. The aim of the present study was to identify the prevalence of metabolic syndrome (MetS) and its association with RCC among urologic patients. Materials and Methods: The study included a total of 355 participants (117 adult RCC patients and 238 age matched controls) divided into groups, with and without MetS diagnosed using the criteria of the American Heart Association/The National Heart Lung and Blood Institute. Groups were compared statistically and logistic regression analysis was performed to investigate the impact of MetS criteria on RCC risk. Results: Of the 117 RCC patients, 52 (44.4%) and of the 238 controls, 37 (15.5%) had MetS. A significant association (p<0.001) was found between the presence of MetS and RCC (OR: 4.35; 95% CI=2.62-7.21). As the number of MetS components accumulated from 3 to 5, RCC risk increased likewise from 4 to 6 times. Conclusions: MetS is more prevalent in RCC patients in Turkey compared to controls. Risk increases with the number of coexisting MetS components.

Prognostic Factors and Adjuvant Treatments for Surgically Treated Cancers of the Biliary Tract: A Multicentre Study of the Anatolian Society of Medical Oncology (ASMO)

Unal, Olcun Umit,Oztop, Ilhan,Assoc, Tugba Kos,Turan, Nedim,Kucukoner, Mehmet,Helvaci, Kaan,Berk, Veli,Sevinc, Alper,Yildiz, Ramazan,Cinkir, Havva yesil,Tonyali, Onder,Demirci, Umut,Aktas, Bilge,Balak Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: Biliary tract cancers are rare, and surgical resection is the standard treatment at early stages. However, reports on the benefits of adjuvant treatment following surgical resection are conflicting. This study aimed to evaluate the factors affecting survival and adjuvant treatments in patients with surgically treated biliary tract cancers. Materials and Methods: Patient clinical features, adjuvant treatments, and efficacy and prognostic factor data were evaluated. Survival analyses were performed using SPSS 15.0. Results: The median overall survival was 30.7 months (95% confidence interval [CI], 18.4-42.9 months). Median survival was 19 months (95% CI, 6-33) for patients treated with fluorouracil based chemotherapy and 53 months (95% CI, 33.2-78.8) with gemcitabine based chemotherapy(p=0.033). On univariate analysis, poor prognostic factors for survival were galbladder localization, perineural invasion, hepatic invasion, a lack of adjuvant chemoradiotherapy treatment, and a lack of lymph node dissection. On multivariate analysis, perineural invasion was a poor prognostic factor (p=0.008). Conclusions: Biliary tract cancers generally have poor prognoses. The main factors affecting survival are tumour localization, perineural invasion, hepatic invasion, adjuvant chemoradiotherapy, and lymph node dissection. Gemcitabine-based adjuvant chemotherapy is more effective than 5-fluorouracil-based chemotherapy.

Salvage Treatment Experience in Advanced Synovial Sarcoma: a Multicenter Retrospective Analysis of the Anatolian Society of Medical Oncology

Yetisyigit, Tarkan,Arpaci, Erkan,Seber, Erdogan Selcuk,Kucukoner, Mehmet,Kos, Fatma Tugba,Sonmez, Ozlem Uysal,Alici, Suleyman,Akman, Tulay,Aktas, Bilge,Yildiz, Ramazan,Gunaydin, Yusuf,Inanc, Mevlude,D Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

Background: We aimed to evaluate prognostic factors and response rates to various treatment approaches to patients with synovial sarcoma in an advanced setting. Materials and Methods: We retrospectively reviewed the medical records of 55 patients (18 pts; 32.7% women) diagnosed with synovial sarcomas. Twenty had metastatic disease at the time of diagnosis while the remainder of the study group consisted of patients who developed metastatic or inoperable locally advanced disease during follow up. Results: The median follow up time was 15 months (range: 1-53). Regarding outcomes for the 55 patients, 3 and 5 year overall survival rates were 26% and 14%, respectively. In univariate analyses among demographic factors female gender was associated with a better outcome (p=0.030). Patients with early progressing disease (<2 years) had a worse prognosis when compared to patient group with late relapse, but this difference did not reach statistical significance (p=0.056). According to multivariate Cox regression analysis patients who had undergone metastasectomy had a significant survival advantage (p=0.044). The overall response rate to different salvage chemotherapy regimens given as second line treatment was around 42.9-53.9% for all regimes. There were no statistically significant differences between chemotherapy regimens given in either second or third line settings in terms of overall survival. Conclusions: We observed no major differences in terms of response rate and survival between different salvage chemotherapy regimens. Although metastatic disease still carries a poor prognosis, metastasectomy was found to be associated with improved survival.