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Öğe Assessment of pretreatment albumin-bilirubin grade in pancreatic cancer patients with liver metastasis(Zerbinis Publications, 2020) Sakin, A.; Sahin, S.; Sakin, A.; Atci, M.M.; Yasar, N.; Arici, S.; Geredeli, C.Purpose: This study aimed to assess the effect of pretreatment albumin-bilirubin (ALBI) score on treatment outcomes in pancreatic cancer (PC) patients with liver metastasis at the time of diagnosis treated with chemotherapy (CT) in the first-line setting. Methods: This was a retrospective study of 273 PC patients ?18 years of age who had liver metastasis at the time of diagnosis and received CT in the first-line. ALBI score was calculated through the following formula; [(log10 bilirubin (?mol/L)×0.66)+[albumin(g/l)×?0.0852]. Patients were stratified into 3 categories based on the ALBI score as follows; grade I:ALBI ?-2.60, grade II:-2.60-1.39. Results: A total of 273 patients, [180 (65.9%) men and 93 (34.1%) women], were evaluated. The median age was 60 years. ALBI grade was I in 45 (16.4%) patients, II in 156 (57.1%) patients, and III in 72 (26.5%) patients. Based on the ALBI grade, median progression-free survival (mPFS) was 9 months in grade I patients, 6 months in grade II patients, and 4 months in grade III patients (p=0.002), with median overall survival (mOS) durations of 12 months vs. 8 months vs. 5 months, respectively (p<0.001). Multivariate analysis showed that ALBI grade II (HR,1.543) or III (HR,2.260) negatively affected survival. Conclusion: A higher pretreatment ALBI grade is related to worse OS and PFS in PC patients with liver metastasis treated with a first-line CT, and therefore it can help predict the treatment outcomes in these patients. © 2020 Zerbinis Publications. All rights reserved.Öğe Experimental investigation and modelling of surface roughness and resultant cutting force in hard turning of AISI H13 Steel(Iop Publishing Ltd, 2016) Boy, M.; Yasar, N.; Ciftci, I.In recent years, turning of hardened steels has replaced grinding for finishing operations. This process is compared to grinding operations; hard turning has higher material removal rates, the possibility of greater process flexibility, lower equipment costs, and shorter setup time. CBN or ceramic cutting tools are widely used hard part machining. For successful application of hard turning, selection of suitable cutting parameters for a given cutting tool is an important step. For this purpose, an experimental investigation was conducted to determine the effects of cutting tool edge geometry, feed rate and cutting speed on surface roughness and resultant cutting force in hard turning of AISI H13 steel with ceramic cutting tools. Machining experiments were conducted in a CNC lathe based on Taguchi experimental design (L-16) in different levels of cutting parameters. In the experiments, a Kistler 9257 B, three cutting force components (Fc, Ff and Fr) piezoelectric dynamometer was used to measure cutting forces. Surface roughness measurements were performed by using a Mahrsurf PS1 device. For statistical analysis, analysis of variance has been performed and mathematical model have been developed for surface roughness and resultant cutting forces. The analysis of variance results showed that the cutting edge geometry, cutting speed and feed rate were the most significant factors on resultant cutting force while the cutting edge geometry and feed rate were the most significant factor for the surface roughness. The regression analysis was applied to predict the outcomes of the experiment. The predicted values and measured values were very close to each other. Afterwards a confirmation tests were performed to make a comparison between the predicted results and the measured results. According to the confirmation test results, measured values are within the 95% confidence interval.Öğe Factors affecting survival in patients with isolated liver-metastatic colorectal cancer treated with local ablative or surgical treatments for liver metastasis(Zerbinis Publications, 2019) Sakin, A.; Sahin, S.; Atci, M.M.; Yasar, N.; Geredeli, C.; Aribal, S.; Alemdar, A.Purpose: Local treatments for isolated synchronous or metachronous liver metastases in colorectal cancer (CRC) have been shown to improve overall survival (OS). The aim of this study was to investigate the factors affecting OS in CRC patients with isolated liver metastasis in whom the primary tumor and corresponding liver metastasis were treated with curative intent using local ablative or surgical methods. Methods: A total of 47 CRC patients presenting with an initial or subsequent isolated liver metastasis, who were treated with local surgical or ablative treatment for liver metastasis with curative intent, were enrolled in this study between 2007 and 2017. The possible factors affecting OS were analyzed. Results: Out of the 47 patients, 35 (74.5%) were male. The median age was 61 (25-80) years. Thirty-four (72.3%) patients underwent liver metastasectomy, while 13 (27.7%) patients were treated with non-surgical local ablative therapies (NSLAT) for liver metastasis. Median OS (mOS) could not be reached in patients who underwent metastasectomy at the time of diagnosis compared to 55 months in those undergoing metastasectomy following a chemotherapy period (p=0.03). Patients treated with NSLAT had a mOS of 60 months compared to “not reached’’ in those who underwent liver metastasectomy (p=0.45). mOS was higher in patients with pT4 stage vs.Öğe Finite element modeling of tool stresses on ceramic tools in hard turning(Kaunas Univ Technol, 2017) Gunay, M.; Korkmaz, M. E.; Yasar, N.Hard turning process has been developed as a possible alternative instead of more expensive cylindrical grinding operations. This process involves many cutting conditions like traditional turning such as machining parameters, nose radius and tool geometry. This study aims that cutting force components (F-f, F-r, F-c) and cutting tool stresses depending on cutting conditions which are cutting speed, depth of cut and feed rate have been investigated in hard turning of DIN 1.2344 tool steel using uncoated ceramic tools. The experiments of hard turning were performed based on full factorial design. The distributions of cutting tools stresses were analyzed based on finite element method by using ANSYS software. ANOVA results showed that the most important factor on all cutting force components is the depth of cut while cutting speed has insignificant effect. In the results of study, it is shown that cutting tool image taken from ANSYS via finite element analysis and tool microscope are very similar. It is possible to say that the boundary conditions for loading of cutting force components are correct and the prediction of cutting tool stresses by finite element analysis can be determined in hard tuning processes.Öğe Mean platelet volume and platelet distribution width correlates with prognosis of early colon cancer(Zerbinis Publications, 2020) Sakin, A.; Sahin, S.; Sakin, A.; Karatas, F.; Samanci, N.S.; Yasar, N.; Arici, S.Purpose: Several platelet indices have been linked to prognosis of various cancers, including metastatic colorectal cancer. The aim of this study was to investigate the prognostic effect of mean platelet volume (MPV) and platelet distribution width (PDW) in early colon cancer (CC) patients. Methods: This retrospective study included early CC patients who were followed up and treated between 2005 and 2017. Relapse free survival (RFS) and overall survival (OS) were determined with respect to several demographic and clinical characteristics of patients, including MPV and PDW. The cut-off value was determined as >8.5 fL for MPV (sensitivity: 67.1%, specificity 54.5%) and ?16% for PDW (sensitivity: 66.7%, specificity: 60.0%). Results: The study included 394 patients, 53.3% of which were male. Stage I, II, and III patients constituted 8.9%, 46.4%, and 44.7% of the study population, respectively. Among all patients, RFS and OS were significantly longer in patients with MPV?8.5 fL and PDW>16 fL (p<0.001 and p=0.011 for MPV, respectively; and p<0.001 and p=0.026 for PDW, respectively). In patients with stage III disease, those with MPV?8.5 fL had significantly longer RFS and OS compared to those with MPV >8.5 fL (p<0.001 and p=0.001, respectively). On the other hand, those with PDW>16% had significantly longer RFS than that in those with PDW ?16 fL among stage III patients (p<0.001). In multivariate analysis, stage, perineural invasion, lymphovascular invasion, adjuvant treatment, CEA, CA19-9, PDW, and MPV were found the most significant factors affecting RFS. Conclusion: Our study suggests that elevated MPV and decreased PDW appear to be unfavorable prognostic factors in early CC, especially in patients with stage III disease. Considering the wide availability and accessibility of these indices, it is reasonable to designate further larger prospective studies to clarify and verify their potential roles in early CC. © This work by JBUON is licensed under a Creative Commons Attribution 4.0 International License.
