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      • KCI등재

        The Effects of Triton X-100 and Tween 80 Surfactants on the Thermal Performance of a Nano-Lubricant: An Experimental Study

        Mustafa Akkaya,Tayfun Menlik,Adnan Sözen,Metin Gürü 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.3

        In this experimental study, experiments were carried out using a nano-lubricant consisting of polyol ester (POE)—titanium dioxide (TiO2)—surfactant instead of POE oil used in the compressor in a refrigeration system cycle test apparatus. The main aim of the study was to provide more efficient operation of the refrigeration system. Triton X100 (TX-100) and sorbitan polyoxyethylene monooleate (Tween 80) were used as the surface-active material. Nano-lubricants were formed by mixing TiO2 nanoparticles with POE oil at different concentrations. At these different nanoparticle concentrations, 0.5% of the surfactant was used. The reason for using a surfactant in the nano-lubricant was to prevent agglomeration in the mixture. TX-100 and Tween 80 surfactants were also used to study the effects of the surfactant on the nano-lubricant. Experiments were carried out using three different concentrations and three measurements for each concentration using the POE/TiO2/surfactant nano-lubricants. The best improvement was achieved when a nano-lubricant consisting of a mixture of TX-100 and POE oil with a concentration of 1.5% TiO2 was used. The improvement in coefficient of performance (COP) for the refrigeration cycle was 39.42%.

      • KCI등재

        Tibial Base Plate for Total Knee Arthroplasty: Symmetric or Asymmetric?

        Murat Bozkurt,Mustafa Akkaya,Mesut Tahta,Safa Gursoy,Ahmet Firat 대한정형외과학회 2017 Clinics in Orthopedic Surgery Vol.9 No.3

        Background: Ideal positioning and best coverage of the tibial base plate are essential in total knee arthroplasty. There are 2 types of tibial base plates: symmetric and asymmetric. The superiority of one to the other is still controversial. The aim of this study was to compare symmetric and asymmetric tibial base plates for total knee arthroplasty in terms of rotational alignment and coverage. Methods: The study was conducted on a total of 80 cadaveric tibial bones. Two surgeons were asked to place 20 symmetric (group 1) and 20 asymmetric (group 2) tibial base plates taking care to ensure the best coverage that they were able to determine. Afterwards, the rotational errors and coverage were assessed with reference to the posterior tibial margin and posterior condylar axis on the three-dimensional computed tomography (3D CT) scan. In the second part of the study, the surgeons were asked to place 20 symmetric (group 3) and 20 asymmetric (group 4) base plates taking care to ensure the best rotational alignment. The rotational errors and the areas uncovered or overstuffed after the application were measured on the 3D CT scan. Results: On the comparison of rotational errors, while there was no significant difference between group 1 and group 2 in terms of coverage (p = 0.624), the mean external rotation error was significantly greater in group 2 (p = 0.034). On the comparison of coverage, while there was no significant difference between group 3 and group 4 in terms of rotation (p = 0.36), the mean ratios of the uncovered tibial surface to the total tibial surface (p = 0.041) and also the overstuffed area to the total base plate surface (p = 0.029) were significantly greater in group 4. Conclusions: The determination of correct size and rotation of the tibial component is essential for favorable outcomes of total knee arthroplasty. In this study, the symmetric tibial base plate design was more effective than the asymmetric design in providing the ideal tibial rotation and coverage.

      • KCI등재SCOPUS

        Adult Proximal Humeral Locking Plate Is a Good Alternative Option in the Treatment of Adolescent Subtrochanteric Femur Fractures: A Case Series and Literature Review

        ( Ceyhun Çag˘lar ),( Serhat Akçaalan ),( Merve Bozer ),( Mustafa Akkaya ) 대한고관절학회 2022 Hip and Pelvis Vol.34 No.4

        Purpose: Management of pediatric subtrochanteric femur fractures (SFFs) is difficult. The aim of this study was to evaluate the outcomes of adolescent SFFs treated with adult proximal humeral locking plates (PHLPs). Materials and Methods: A retrospective analysis of 18 adolescents (11 male, 7 female) with a diagnosis of SFF who underwent internal fixation with a PHLP was conducted. Data regarding injury mechanism, fracture pattern, and time to union were recorded for all patients. In addition, a clinical and functional evaluation of patients was performed using the Harris hip score (HHS), Iowa hip score (IHS), modified Merle d’Aubigne-Postel score (MMAPS), Flynn criteria, and hip range of motion (ROM). Results: The mean age of the patients was 12.72±2.05 years (range, 10-16 years). Radiological observation was performed for evaluation of five different injury mechanisms and different fracture patterns in patients. The mean postoperative HHS was 92.27±5.61, the mean IHS was 90.88±6.46, and the mean MMAPS was 17.22±0.94. According to the Flynn criteria, excellent results were achieved in 14 cases and satisfactory results were obtained in four cases. Measurements of the patients’ mean hip ROM values were as follows: 17.77±3.52。in extension, 115.27±6.74。in flexion, 43.05±3.48。in abduction, 27.50±4.28。in adduction, 42.22±4.60。in internal rotation, and 42.22±3.91。in external rotation. Conclusion: Surgery performed on adolescent patients using an adult PHLP showed good, safe results. Therefore, it should be considered as an alternative option.

      • KCI등재

        Prognostic Significance of Retroperitoneal Lymphadenectomy, Preoperative Neutrophil Lymphocyte Ratio and Platelet Lymphocyte Ratio in Primary Fallopian Tube Carcinoma: A Multicenter Study

        Kemal Gungorduk,Ibrahim E. Ertas,Aykut Ozdemir,Emrah Akkaya,Elcin Telli,Salih Taskin,Mehmet Gokcu,Ahmet Baris Guzel,Tufan Oge,Levent Akman,Tayfun Toptas,Ulas Solmaz,Askın Dogan,Mustafa Cosan Terek,Muz 대한암학회 2015 Cancer Research and Treatment Vol.47 No.3

        Purpose The purpose of this study is to evaluate the prognostic role of preoperative neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) and the need for para-aortic lymphadectomy in patients with primary fallopian tube carcinoma (PFTC). Materials and Methods Ninety-one patients with a diagnosis of PFTC were identified through the gynecologic oncology service database of six academic centers. Clinicopathological, surgical, and complete blood count data were collected. Results In univariate analysis, advanced stage, suboptimal surgery, and NLR > 2.7 were significant prognostic factors for progression-free survival, whereas in multivariate analysis, only advanced stage and suboptimal surgery were significant. In addition, in univariate analysis, cancer antigen 125 ! 35 U/mL, ascites, advanced stage, suboptimal surgery, NLR > 2.7, PLR > 233.3, platelet count ! 400,000 cells/mm3, staging type, and histological subtype were significant prognostic factors for overall survival (OS); however, in multivariate analysis, only advanced stage, suboptimal surgery, NLR > 2.7, and staging type were significant. Inclusion of pelvic and para-aortic lymphadenectomy in surgery showed significant association with longer OS, with a mean and median OS of 42.0 months and 35.5 months (range, 22 to 78 months), respectively, vs. 33.5 months and 27.5 months (range, 14 to 76 months), respectively, for patients who underwent surgery without para-aortic lymphadenectomy (hazard ratio, 3.1; 95% confidence interval, 1.4 to 5.7; p=0.002). Conclusion NLR (in both univariate and multivariate analysis) and PLR (only in univariate analysis) were prognostic factors in PFTC. NLR and PLR are inexpensive and easy tests to perform. In addition, patients with PFTC who underwent bilateral pelvic and para-aortic lymphadenectomy had longer OS.

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