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  1. Home
  2. Browse by Author

Browsing by Author "Celik E."

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    Wear behavior of flame-sprayed Al2O3 -TiO2 coatings on plain carbon steel substrates
    (2005) Kusoglu I.M.; Celik E.; Cetinel H.; Ozdemir I.; Demirkurt O.; Onel K.
    In this study, Al2O3-TiO2 powders were sprayed using a flame-spray technique after a NiCrMo bond layer was deposited on plain carbon steel substrate. The produced layers were characterized by X-ray diffraction (XRD), optical microscope, scanning electron microscope (SEM) including energy-dispersive spectroscopy (EDS), surface roughness and microhardness tester. Friction and wear behaviour of the coatings were also evaluated in the present study. The Al2O3-TiO2 coatings were subjected to sliding wear against AISI 303 stainless steel counter body under dry and acidic environments. A pin-on-plate type apparatus was used with normal loads in the range of 49-129 N. Wear resistance of the coatings in acid environment is better than that in dry conditions. © 2005 Elsevier B.V. All rights reserved.
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    Tribological behavior of Cr2O3 coatings as bearing materials
    (2008) Cetinel H.; Celik E.; Kusoglu M.I.
    In this study, the tribological behavior of Cr2O3/Ni8.5Cr7Al5Mo2Si2B2FeTiO2 coatings for bearing materials was investigated in dry and acid conditions. Flame spray technique was used in order to deposit coating materials onto AISI 304L steel substrate. The coated samples were characterized by means of an optical microscope, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), surface roughness and microhardness testers. The wear experiments were performed under dry and acid environments using a pin-on-plate configuration against AISI 303 counter material for different loads. It was found that in acid environment, the amount of wear loss is less than that of in dry condition and applied load level is more effective in dry condition. In SEM study, the effect of plastic deformation of adherent and compacted debris particles on friction of the coatings was investigated. © 2007 Elsevier B.V. All rights reserved.
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    Finite-element model of the indentation for ybco-based superconductor thin films
    (2013) Culha O.; Turkmen I.; Toparh M.; Celik E.
    Superconducting films with poor mechanical properties are useless even if they possess good transport and flux-pinning properties. Since additive particles as pinning centers are important changes in a microstructure, their effect on the micromechanical properties such as Young's modulus and hardness have to be investigated with respect to the additional-particle type and quantity, using experimental and numerical methods. In this study, films were dip-coated onto (001) SrTiO3 (STO) single-crystal substrates with metalorganic deposition using the trifluoroacetate (TFA-MOD) technique. The phase analysis and the microstructure of the superconducting thin films were determined with an X-ray diffractometer (XRD) and a scanning electron microscope (SEM). The mechanical-property variations of the pure YBCO and the YBCO thin films with Mn (reacting as BaMnO3) were experimentally obtained with nanoindentation techniques. Thus, the BaMnO3 nanoparticle effects on the structural and mechanical properties of the films were observed. According to the nanoindentation results, the Young's modulus and indentation hardness of the films decreased from 88.54 GPa to 76.47 GPa and from 12.51 GPa to 3.88 GPa, respectively, depending on the additive particles. In addition, the finite-element modeling (FEM) of the indentation was applied to estimate the failure stress/stress distribution relation at the contact region between the indenter and the surface of a YBCO-based thin film, obtaining the same force/penetration depth curve as with the indentation experiment. According to these main aims of FEM, the mesh-design effect, material properties and the boundary condition of the axisymmetric model were chosen and optimized to obtain the mechanical results of the instrumented indentation.
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    Characterization and determination of mechanical properties of ybco superconducting thin films with manganese using the tfa-mod method
    (2013) Culha O.; Birlik I.; Toparli M.; Celik E.; Engel S.; Holzapfel B.
    The aim of this study is to determine the microstructure, superconducting and mechanical properties of YBa2Cu3O6.56 (YBCO) and YBCO thin films with a manganese (Mn) addition. All the YBCO superconducting films (undoped and Mn-doped) were dip-coated onto (001) SrTiO3 (STO) single-crystal substrates with a metalorganic deposition using the trifluoroacetate (TFA-MOD) technique. The phase analysis, microstructure, surface morphologies and critical temperature (Tc) of the superconducting thin films were determined with an X-ray diffractometer (XRD), a scanning electron microscope (SEM), an atomic force microscope (AFM) and an inductive Tc measurement system. Since the main issue of this study is to determine the mechanical-property variations of the superconducting thin films with/without a Mn addition, the adhesion strength of these films on a STO substrate was tested with a Shimadzu scratch tester. Depending on the Mn addition, the critical forces of pure films increase from 56.23 mN, 58.63 mN and 60.11 mN for pure YBCO, YBCO with 0.05 g and 0.10 g of Mn. Furthermore, Young's modulus and the hardness of the undoped and Mn-doped YBCO thin films were measured with a CSM Berkovich nanoindenter using the load-unload sensing analysis under a 0.3 mN applied load.
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    Fabrication and characterization of nanostructured anatase TiO2 films prepared by electrochemical anodization and their photocatalytic properties
    (Elsevier Ltd, 2015) Yurddaskal M.; Dikici T.; Yildirim S.; Yurddaskal M.; Toparli M.; Celik E.
    In this study, nanostructured anatase titanium dioxide (TiO2) films were fabricated by electrochemical anodization of titanium first, and then annealed at 500 °C for 2 h. Effect of electrolyte concentration, anodization time and electrolyte temperature on the surface morphology of the resulting TiO2 thin films were investigated. The phase structures, surface morphology and chemical composition were analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity tests of the samples were evaluated by the degradation of aqueous methylene blue (MB) solutions under UV light illumination for different periods of time. The results showed that the structure of nanostructured TiO2 films depended strongly on the anodization parameters. It was found that there were micro-scale pores (<10 μm) and nano-scale pores (diameter in the range from 40 to 70 nm) on the anodized titanium surfaces. This study indicated that structures, surface morphology, and surface area of the nanostructured anatase TiO2 films played an important role on their photocatalytic performance. The results clearly proved that nanostructured anatase TiO2 film prepared with optimum process parameters resulted in enhancement of the photocatalytic activity. © 2015 Elsevier B.V.
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    The relationship between uterine prolapse and premalignant endometrial pathology
    (S.O.G. CANADA Inc., 2016) Gene M.; Celik E.; Eskicioglu F.; Gur E.B.; Kurtulmus S.; Gulec E.; Guclu S.
    Objective: The aim of this study was to stress the importance of performing a thorough uterine assessment before selecting an organ- sparing surgery in patients presenting with uterine prolapse and no other complaints. Materials and Methods: This study included a total of 111 participants who presented with pelvic organ prolapse and underwent hysterectomy for grades 3-4 uterine prolapse. The post- hysterectomy histopathology results were classified as benign (atrophic endometrium, proliferative or secretory endometrium) or pathologic (endometrial hyperplasia, endometrial polyp, adenomyosis, myoma uteri, and endometrium carcinoma). Results: Of the 111 patients enrolled in this study, 23 (20.2%) had endometrial hyperplasia, eight (7.2%) had endometrial polyps, 30 (27%) had uterine fibroids, and 20 (18%) had adenomyosis. Conclusion: There may be premalignant lesions of the endometrium in both premenopausal and postmenopausal women presenting with uterine prolapse and no other symptoms. A chronic inflammatory process resulting from the extra-vaginal location of the uterus may play a role in the development of these lesions. Further studies are needed on this subject.
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    Synthesis and characterization of Ag doped TiO 2 heterojunction films and their photocatalytic performances
    (Elsevier B.V., 2016) Demirci S.; Dikici T.; Yurddaskal M.; Gultekin S.; Toparli M.; Celik E.
    In this study, undoped and silver (Ag) doped titanium dioxide (TiO 2 ) films were successfully synthesized by sol-gel spin coating technique on the Si substrates. Photocatalytic activities of the TiO 2 films with different Ag content were investigated for the degradation of methylene blue (MB) under UV light irradiation. The crystal phase structure, surface morphology, chemical and optical properties of Ag-doped TiO 2 films were characterized using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis spectrophotometer, and FTIR spectrophotometer. The results showed that the Ag-doped TiO 2 films calcined at 500 °C had the crystalline anatase phases and the surface morphologies with some cracks. Ag substitution into TiO 2 matrix enhanced the photocatalytic activity of TiO 2 films under UV light irradiation as compared to the undoped TiO 2 film. Furthermore, the results indicated that the 0.7% Ag doped TiO 2 film exhibited a superior photocatalytic activity than that of undoped and other Ag-doped TiO 2 films. This study demonstrated the potential of an application of Ag doped films to efficiently treat dissolved organic contaminants in water. © 2016 Elsevier B.V.
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    Sol-gel synthesized Sr4Al14O25:Eu2+/Dy3+ blue–green phosphorous as oxygen sensing materials
    (Elsevier B.V., 2016) Aydin I.; Ertekin K.; Demirci S.; Gultekin S.; Celik E.
    In this study, we utilized newly synthesized Sr4Al14O25:Eu2+/Dy3+ blue–green phosphors along with silver nanoparticles (AgNPs) for fabrication of oxygen sensitive materials. To the best of our knowledge oxygen sensing mechanism of the offered design is totally different from the previously published works. One-component silicone: poly (1-trimethylsilyl-1-propyne), two component phenyl bearing silicone, plasticized polymethylmethacrylate, and ethylcellulose (EC) were tested as matrix materials. Electrospun fibers, porous and smooth thin films were produced by electrospinning or knife coating technique. Oxygen induced luminescence of the phosphors at 544 nm was followed as the analytical signal. Utilization of silver nanoparticles in silicone along with phosphors resulted with a 7.14 fold enhancement in the signal intensity and significant spectral response towards oxygen competing with the signals of the oxygen sensors utilizing metalloporphyrins or ruthenium complexes. We observed high sensitivity and stability, increased surface area and an enhancement in all sensor dynamics. Linearity of the calibration plots was superior for the pO2 range of 0.0–20.0% with respect to the previously reported ones. When stored at the ambient air of the laboratory there was no significant drift in signal intensity after 12 months. Our sensitivity and stability tests are still in progress. © 2016 Elsevier B.V.
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    Luminescent properties of scintillator nanophosphors produced by flame spray pyrolysis
    (Elsevier B.V., 2017) Yildirim S.; Karsu Asal E.C.; Ertekin K.; Celik E.
    In the present work flame spray pyrolysis synthesis and characterization of the nano-scale phosphors; M′-YTaO4 and M′-Y(Ta0.85Nb0.15)O4 have been studied for the first time. Phase and elemental analysis of the produced nanophosphors were carried out by X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS) measurements, respectively. The surface morphology and particle size of the nanophosphors were identified using scanning electron microscopy (SEM). The XRD results reveal that the nanophosphors have monoclinic M′-YTaO4 and M′-Y(Ta0.85Nb0.15)O4 phases belonging to the presence of M´-form of fergusonite structure. The particle sizes of the nanophosphors were found to be in the range of 50–100 nm. The spectroscopic characterization was performed by both radioluminescence (RL) and thermally stimulated luminescence (TSL) measurements after exposure to X-ray irradiation. Also, photoluminescence and decay times were investigated under UV excitation. The nanophosphors can be concluded as appropriate emissive materials for imaging, display and scintillator applications due to the efficient photoluminescence, moderate radioluminescence (RL) and thermally stimulated luminescence characteristics. © 2017 Elsevier B.V.
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    Enhanced photocatalytic properties of Sn-doped ZnO nanoparticles by flame spray pyrolysis under UV light irradiation
    (Turkish Chemical Society, 2018) Yurddaskal M.; Yildirim S.; Dikici T.; Yurddaskal M.; Erol M.; Aritman I.; Celik E.
    Zinc oxide (ZnO) is widely used in different areas thanks to its unique photocatalytic, optic and electrical properties. Sn doped ZnO nanoparticles were synthesized through flame spray pyrolysis (FSP) technique. The Sn dopant concentrations were 1, 3, 5, 7 and 9 at. % in produced ZnO nanoparticles. The structural analysis of the produced powders was performed by X-Ray Diffraction (XRD) methods. The surface morphology and particle size distribution of the nanoparticles were identified using scanning electron microscopy (SEM), and dynamic light scattering (DLS) techniques. In addition to this, produced photocatalysts were evaluated for degradation of aqueous methylene blue (MB) solutions under UV light irradiation. Sn-doped nanoparticles have superior photocatalytic activity compared to un-doped ZnO. © 2018, Turkish Chemical Society. All rights reserved.
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    Effects of Zn-doping on the photocatalytic activity and microstructures of nanocrystalline SnO2 powders
    (Turkish Chemical Society, 2018) Yurddaskal M.; Yildirim S.; Dikici T.; Yurddaskal M.; Erol M.; Aritman I.; Uygun H.D.E.; Celik E.
    In this study, undoped and Zn-doped SnO2 nanoparticles in different concentrations were synthesized by flame spray pyrolysis (FSP) technique. The produced particles were post-annealed after FSP process at 600 °C in order to obtain a crystalline structure. The structural analysis of the produced powders was performed by X-Ray Diffraction (XRD) methods. The surface morphology of the nanoparticles was identified using scanning electron microscopy (SEM). In addition, photocatalytic degradation of aqueous methylene blue (MB) solutions were evaluated using undoped and Zn-doped SnO2 nanoparticles under UV light illumination. Photocatalytic degradation of the MB solutions followed the pseudo-first-order-kinetics and the effect of the Zn doping amount on the photocatalytic reaction was investigated. © 2018, Turkish Chemical Society. All rights reserved.
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    Dielectrical, optical, and structural characterization of TiO2/PVA nanocomposite films for dielectric applications
    (Springer International Publishing, 2018) Gultekin S.; Yildirim S.; Celik E.; Arican Alicikus L.Z.
    In this study, titanium dioxide/poly(vinyl) alcohol (TiO2/PVA) nanocomposite thin films were prepared by a simple spin-coating method for dielectric applications. Structural, morphological, optical, and dielectric properties of samples were analyzed by XRD, SEM, AFM, UV-VIS, and dielectric measurements. The effect of TiO2 nanoparticles on these properties was investigated. It was found that TiO2 nanoparticles lead to increase the crystallinity of nanocomposites. As TiO2 content in the composite structure increases, while average transmittance values decrease, reflectance values increase. The dielectric parameters such as real and imaginary part of complex permittivity which are related to the stored energy and the dissipation (or loss) of energy were significantly affected by the presence of TiO2 nanoparticles. In addition, alternating current (A.C.) conductivity increased with increasing applied frequency. The A.C. conductivity also confirmed that all the samples exhibited the insulator behavior and obeyed the universal power law. © 2018, Australian Ceramic Society.
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    Prediction of nano etching parameters of silicon wafer for a better energy absorption with the aid of an artificial neural network
    (Elsevier B.V., 2018) Kayabasi E.; Ozturk S.; Celik E.; Kurt H.; Arcaklioğlu E.
    To enhance energy absorption of photovoltaics, several etching experiments with various parameters were performed. In addition, an Artificial Neural Network (ANN) simulation was utilized to predict chemical nano etching parameters such as masking and etching durations for Silicon (Si) solar cell applications to reach minimum surface reflectance in an optimum etching duration. Experiments were performed with different masking and etching durations to determine the characteristics of surface reflectance of micro textured n-type single crystalline Si wafers in 25mmx25mm width and 300 µm thickness to provide training data for ANN. For this purpose, solutions with identic properties including Ag nanoparticles were applied with different application durations on the surfaces of n-type single crystalline Si wafers to cover partially the Si surfaces with Ag nano-particles at masking step. After, partially masked Si surfaces were exposed to chemical nano etching to develop nano-sized porous structures under different etching durations in an identic acidic etching solution. For the etching of Si wafers, 32 masking and etching processes were performed. Reflectance measurements and SEM images were evaluated to determine the optimum etching duration resulting the best surface quality with minimum reflectance. In addition, reflectance values were utilized as input data for training, testing and validation steps of developed ANN. In the ANN simulation, 70% of reflectance values were used as training, 15% of reflectance values were used as validation and 15% of reflectance values were used to test data in the ANN. Consequently, surface reflectance values under different masking and etching durations were predicted with the new parameter set by using the trained ANN with a success level above 99%. © 2018 Elsevier B.V.
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    Synthesis and characterizations of LaMnO3 perovskite powders using sol–gel method
    (Springer, 2021) Çoban Özkan D.; Türk A.; Celik E.
    The present research demonstrates the synthesis and characterization of LaMnO3 perovskite powders using the sol–gel technique for solar cell applications. With this respect, LaMnO3 powders were synthesized at two different annealing temperatures by the sol–gel method using La- and Mn-based precursors. Thermal, structural, microstructural, optical and magnetic properties of the powders were characterized through differential thermal analysis-thermogravimetry (DTA-TG), Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Malvern zeta sizer (PSD), UV–Vis spectrometer and vibrating sample magnetometer (VSM). LaMnO3 was synthesized successfully at 500 °C and 850 °C synthesis temperatures, and the bandgap was determined as 1.27 eV for both. The analysis revealed that magnetic properties, crystalline and particle sizes change according to the heat of synthesis. The obtained results indicate promise, especially the low bandgap, that LaMnO3 powders can be used in solar cell applications and can positively affect performance and efficiency. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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    Efficacy and safety of folfiri plus aflibercept in second-line treatment of metastatic colorectal cancer: Real-life data from Turkish oncology group
    (Wolters Kluwer Medknow Publications, 2022) Erol C.; Sendur M.A.N.; Bilgetekin I.; Garbioglu D.B.; Hamdard J.; Akbas S.; Hizal M.; Arslan C.; Sevinc A.; Kucukarda A.; Erdem D.; Kahraman S.; Cakir E.; Demirkiran A.; On S.; Dogan I.; Erdogan A.P.; Koca S.; Kubilay P.; Eren O.O.; Cilbir E.; Celik E.; Araz M.; Ozyukseler D.T.; Yildirim M.E.; Bahceci A.; Taskaynatan H.; Oyman A.; Deniz G.I.; Menekse S.; Kut E.; Gulmez A.; Sakin A.; Nayir E.; Acar R.; Sen E.; Inal A.; Turhal S.; Kaya A.O.; Paydas S.; Tastekin D.; Hacibekiroglu I.; Cincin I.; Bilici A.; Mandel N.M.; Dede D.S.; Akinci M.B.; Oksuzoglu B.; Uncu D.; Yalcin B.; Artac1 M.
    Aims: The addition of aflibercept to the fluorouracil and irinotecan (FOLFIRI) regimen significantly improved clinical outcomes in patients with metastatic colorectal cancer (CRC) previously treated with oxaliplatin. We aimed to investigate the efficacy and safety of second-line FOLFIRI and aflibercept combination in patients with metastatic CRC in real-life experience. Materials and Methods: Four hundred and thirty-three patients who treated with FOLFIRI and aflibercept in the second-line were included in the study. The clinical and pathological features of the patients were recorded retrospectively. Survival (overall and progression-free survival [PFS]), response rates, and safety data were analyzed. Results: The median age was 61. Majority of patients (87.5%) received first-line bevacizumab and 10.1% of patients received anti-epidermal growth factor receptor agents. About 80% of patients had KRAS, 18.6% of patients had NRAS, and 6.4% of patients had BRAF mutations. The median OS was 11.6 months (95% confidence interval [CI], 10.6-12.6) and the median PFS was 6 months (95% CI, 5.5-6.5). About 4.6% of patients had complete response and 30.6% of patients had partial response as best tumor response. Grade 1-2 toxicities were seen in 33.4% of patients, while grade 3-4 toxicities were recorded in 27% of patients. Eight patients (2%) died due to treatment toxicity. Conclusions: Overall and PFS were similar in routine clinical practice compared to phase III pivotal VELOUR trial. However, response rates were found to be higher. It was observed that there were fewer adverse events compared to the VELOUR trial. © 2022 Authors. All rights reserved.
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    Design and production of dye-synthesized solar cells with FTO/TiO2/ferroelectric dye/electrolyte/Pt/FTO architecture
    (Springer, 2023) Coban Ozkan D.; Turk A.; Celik E.
    A new approach for the application of dye-synthesized solar cells is realized by using perovskite and single oxide micro/nanopowders. With respect to the literature, the desired energy efficiency of dye-synthesized solar cells is a priori established as perovskite and single oxide micro/nanopowders in a composite structure. In the present work, in order to produce dye-synthesized solar cells with FTO/TiO2/ferroelectric/dye/electrolyte/Pt/FTO architecture, their precursor solutions were prepared by using nitrate-based salts, solvents, and chelating agents. The obtained gel films were dried at 200 °C for 2 h and then annealed at temperatures of 500 °C and 850 °C for 2 h in the air. TiO2 and LaFeO3 powders were characterized through DTA-TGA, FTIR, XRD, SEM, and UV-Vis spectrometer machines. In line with the results obtained, dye-sensitized solar cell production, which can also be called ferroelectric photovoltaic cells with a combination of TiO2, was produced. It was found that the production of continuously applicable and sustainable dye-sensitive solar cells using LaFeO3 with together TiO2 powders can be useful as innovative and futuristic approaches. © 2023, The Author(s) under exclusive licence to Australian Ceramic Society.
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    Evaluation of 601 children with multisystem inflammatory syndrome (Turk MISC study)
    (Springer Science and Business Media Deutschland GmbH, 2023) Yilmaz D.; Ekemen Keles Y.; Emiroglu M.; Duramaz B.B.; Ugur C.; Aldemir Kocabas B.; Celik T.; Ozdemir H.; Bayturan S.; Turel O.; Erdeniz E.H.; Cakici O.; Cakmak Taskin E.; Erbas İ.C.; Genceli M.; Sari E.E.; Caymaz C.; Kizil M.C.; Sutcu M.; Demirbuga A.; Alkan G.; Bagcı Z.; Timurtas Dayar G.; Ozkan E.A.; Tekin Yilmaz A.; Akca M.; Yesil E.; Kara S.S.; Akturk H.; Yasar B.; Umit Z.; Uygun H.; Erdem N.; Buyukcam A.; Karadag Oncel E.; Tuter Oz S.K.; Cetin H.S.; Anil A.B.; Yilmaz R.; Zengin N.; Uzuner S.; Albayrak H.; Borakay O.; Topal S.; Arslan G.; Yazar A.; Ozer A.; Kendirli T.; Kara E.M.; Demirkol D.; Battal F.; Kosker M.; Metin Akcan O.; Kihtir H.S.; Gul D.; Zararci K.; Alakaya M.; Kula N.; Celik E.; Petmezci E.; Evren G.; Kara Aksay A.; Konca C.; Sert A.; Arslan D.; Bornaun H.; Tekeli O.; Bal A.; Sahin I.O.; Demir S.; Sap F.; Akyol M.B.; Tanidir I.C.; Donmez Y.N.; Ucar T.; Coban S.; Arga G.; Hancerli Torun S.; Karpuz D.; Celik S.F.; Varan C.; Elmali F.; Oncel S.; Belet N.; Hatipoglu N.; Dalgic Karabulut N.; Turgut M.; Somer A.; Kuyucu N.; Dinleyici E.C.; Ciftci E.; Kara A.
    Purpose: Due to its link with the 2019 coronavirus, the multisystem inflammatory syndrome in children (MISC) has garnered considerable international interest. The aim of this study, in which MISC patients were evaluated multicenter, and the data of the third period of the Turk-MISC study group, to compare the clinical and laboratory characteristics and outcomes of MISC patients who did and did not require admission to an intensive care unit (ICU). Methods: This retrospective multicenter observational study was carried out between June 11, 2021, and January 01, 2022. The demographics, complaints, laboratory results, system involvements, and outcomes of the patients were documented. Results: A total of 601 patients were enrolled; 157 patients (26.1%) required hospitalization in the intensive care unit (ICU). Median age was 8 years (interquartile range (IQR) 4.5–11.3 years. The proportion of Kawasaki disease-like features in the ICU group was significantly higher than in the non-ICU group (56.1% vs. 43.2% p = 0.006). The ICU group had considerably lower counts of both lymphocytes and platelets (lymphocyte count 900 vs. 1280 cells × μL, platelet count 153 vs. 212 cells × 103/ μL, all for p< 0.001). C-reactive protein, procalcitonin, and ferritin levels were significantly higher in the ICU group (CRP 164 vs. 129 mg/L, procalcitonin 9.2 vs. 2.2 μg/L, ferritin 644 vs. 334 μg/L, all for p< 0.001). Being between ages 5–12 and older than 12 increased the likelihood of hospitalization in the ICU by four [95% confidence intervals (CI)1.971–8.627] and six times (95% CI 2.575–14.654), respectively, compared to being between the ages 0–5. A one-unit increase in log d-dimer (µg/L) and log troponin (ng/L) was also demonstrated to increase the need for intensive care by 1.8 (95% CI 1.079–3.233) and 1.4 times (95% CI 1.133–1.789), respectively. Conclusion: By comparing this study to our other studies, we found that the median age of MISC patients has been rising. Patients requiring an ICU stay had considerably higher levels of procalcitonin, CRP, and ferritin but significantly lower levels of lymphocyte and thrombocyte. In particular, high levels of procalcitonin in the serum might serve as a valuable laboratory marker for anticipating the need for intensive care. What is Known: • Lymphopenia and thrombocytopenia were an independent predictor factors in patients with MISC who needed to stay in intensive care unit. • The possibility of the need to stay in the intensive care unit in patients with MISC who had Kawasaki disease-like findings was controversial compared with those who did not. What is New: • A one-unit increase log D dimer and log troponin was demonstrated to require for intensive care unit by 1.8 and 1.4 times, respectively. • Serum procalcitonin levels had the best performance to predict stay in the intensive care unit stay. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
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    Real-life comparison of afatinib and erlotinib in non-small cell lung cancer with rare EGFR exon 18 and exon 20 mutations: a Turkish Oncology Group (TOG) study
    (Springer Science and Business Media Deutschland GmbH, 2023) Gursoy P.; Tatli A.M.; Erdem D.; Goker E.; Celik E.; Demirci N.S.; Sakin A.; Atci M.M.; Bayram E.; Telli T.A.; Bilgin B.; Bilici A.; Akangunduz B.; Balli S.; Demirkazik A.; Selçukbiricik F.; Menekse S.; Cavdar E.; Ozturk A.; Bekmez E.T.; Turhal S.; Kilickap S.; Yildirim H.Ç.; Oyan B.; Aksoy A.; Turkoz F.P.; Kut E.; Katgi N.; Sakalar T.; Akyol M.; Ellez H.İ.; Topcu A.; Erdoğan A.P.; Pilanci K.N.; Hedem E.; Arak H.; Akdeniz N.; Alan Ö.; Yapar B.; Nart D.; Yumuk P.F.
    Objectives: To compare the survival of first- and second-generation tyrosine kinase inhibitors (TKIs) in patients with rare EGFR exon 18 and exon 20 mutation-positive non-small cell lung cancer (NSCLC). Materials and methods: We retrospectively evaluated survival characteristics of 125 patients with EGFR exon 18 and exon 20 mutated NSCLC who received erlotinib or afatinib as first line treatment between 2012 and 2021 from 34 oncology centres. Since exon 20 insertion is associated with TKI resistance, these 18 patients were excluded from the study. Results: EGFR exon 18 mutations were seen in 60%, exon 20 mutations in 16%, and complex mutations in 24% of the patients with NSCLC who were evaluated for the study. There were 75 patients in erlotinib treated arm and 50 patients in afatinib arm. Patients treated with erlotinib had progression-free survival time (PFS) of 8.0 months and PFS was 7.0 months in the afatinib arm (p = 0.869), while overall survival time (OS) was 20.0 vs 24.8 months, respectively (p = 0.190). PFS of exon 18 mutated arm was 7.0 months, exon 20 mutated arm was 4.3 months, and complex mutation positive group was 17.3 months, and this was statistically significant (p = 0.036). The longest OS was 32.5 months, seen in the complex mutations group, which was not statistically different than exon 18 and in exon 20 mutated groups (21.0 and 21.2 months, respectively) (p = 0.323). Conclusion: In this patient group, especially patients with complex mutations are as sensitive to EGFR TKI treatment similar to classical mutations, and in patients with rare exon 18 and exon 20 EGFR mutation both first- and second-generation EGFR-TKIs should be considered, especially as first- and second-line options. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
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    Influence of Inoculation and Texture on Enhancing Electrical Conductivity in Commercially Pure Aluminum for Squirrel-Cage Asynchronous Electrical Motors
    (Springer Science and Business Media Deutschland GmbH, 2024) Cilingir C.; Turk A.; Yavas A.; Yigit R.; Celik E.
    Abstract: This research focuses on manufacturing and applying highly conductive and non-magnetic aluminum-based materials in rotor construction to reduce conductor losses and increase motor efficiency. The process involves using an electric melting furnace to melt aluminum-boron (Al-B) master alloys at various rates along with 99.7% pure Al and impurities. During melting, the boron reacts with impurity elements in the Al, forming borides that are removed as slag. This interaction removes impurities, eliminating the magnetic properties of the Al and increasing its conductivity. The melted metal is then cast and subjected to heat treatment to achieve desired textures in their structure, further enhancing conductivity in specific directions. The outcome of this study is the production of extra-high-conductivity and non-magnetic materials through an innovative approach that does not require system changes or increase costs compared to current methods. The Al-3B master alloy and heat treatments significantly improve electrical conductivity in aluminum by enhancing metal orientation to (110) and eliminating structural defects. Heat treatments at 400 °C for 2 and 4 hours are most effective. These processes also reduce magnetic characteristics, resulting in improved rotor efficiencies in motor performance. Graphical Abstract: (Figure presented.) © American Foundry Society 2024.
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    Production and Characterization of Highly Conductive Aluminum Metal for Electric Motor Applications
    (Springer, 2025) Yavaş A.; Cilingir C.; Turk A.; Celik E.
    The aim of this research is to produce and develop high-conductive and non-magnetic Al-based materials used in industrial rotors to reduce rotor conductor losses and increase motor efficiency. To achieve this, ETIAL 7 Al metal was melted together with AlB2 and AlB12 inoculant materials at individually added proportions (ranging from approximately 0.025-0.300%) using an induction melting furnace. The removal of boron from Al metal was achieved by the interaction of boron with impurity elements at high temperatures and the formation of borides. Low-density metal borides precipitated into slag and high-density metal borides precipitated at the bottom of the molten metal in the induction furnace. As a result, the metal was rendered non-magnetic and its conductivity increased by removing impurity elements in the Al metal. After the casting process, the metal underwent heat treatment to obtain certain textures in the structure, which further enhanced its conductivity at desired directions. The elemental analysis, phase structure, chemical state, microstructural, electrical, and magnetic properties of the produced Al materials were characterized by using OEM, XRD, XPS, SEM-EDS, IA, and VSM. This study has successfully produced extra-high-conductivity and non-magnetic materials with an innovative approach, without changing the system, and in a cost-efficient manner compared to the current situation. These materials can be used to increase the efficiency of electric motors. © ASM International 2024.

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