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  1. Home
  2. Browse by Author

Browsing by Author "Aydin, I"

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    Determination of Fracture Toughness of Calcium Phosphate Coatings Deposited Onto Ti6Al4V Substrate by Using Indentation Technique
    Aydin, I; Cetinel, H; Pasinli, A
    In this study, fracture toughness values of calcium phosphate (CaP) coatings deposited onto Ti6Al4V substrate were determined by using Vickers indentation method. In this new patent holding method, the activation processes were performed with NaOH and NaOH + H2O2 on the Ti6Al4V material surface. Thicknesses of CaP coatings were measured from crosssections of the samples by using optical microscopy. Vickers indentation tests were performed by using microhardness tester. Young's modulus values of the coatings were determined by using ultra microhardness tester. As a result, fracture toughness (K-1C) values of the CaP coatings produced by using two different activation processes, were calculated by using experimental study results. These were found to be 0.43 MPa m(1/2) and 0.39 MPa m(1/2), respectively. It was determined that the CaP coating on Ti6Al4V activated by NaOH + H2O2 had higher fracture toughness than the CaP coating on Ti6Al4V activated by NaOH.
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    Fracturing and adhesion behavior of hydroxyapatite formed by a citric acid and sodium citrate buffer system
    Aydin, I; Çetinel, H; Pasinli, A; Yuksel, M
    This study aims to examine the fracture and surface adhesion behavior of hydroxyapatite (HA) coatings created in acitric acid-sodium citrate buffer system. Coatings were implemented on the surface of Ti6Al4V. The modulus of elasticity, hardness and adhesion strength values of the presented coatings were determined, the fracture toughness values were calculated and scanning electron microscope (SEM) images were taken as well. Finally, the mechanical properties found by the tests implemented to hydroxyapatite coatings applied on Ti6Al4V, which yielded successful outcomes were compared to the mechanical properties of bone. The fracture toughness achieved in this study was found to be more compatible with the mechanical properties of the original bone itself when compared to the literature findings. Besides, the adhesion strength was found to be remarkably high.
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    Preparation of Hydroxyapatite Coating by Using Citric Acid Sodium Citrate Buffer System in the Biomimetic Procedure
    Aydin, I; Cetinel, H; Pasinli, A; Yuksel, M
    The present study has been aimed to investigate the preparation and analysis of calcium phosphate (CaP) based hydroxyapatite (HA, Ca-10(PO4)(6)(OH)(2)) coatings formed on Ti6Al4V alloys in a new buffer environment. The coating process has been performed by means of biomimetic method. In the study, a synthetic body fluid (SBF), which is fully compatible with human blood plasma, has been prepared for the first time in the literature by using the citric acid - sodium citrate buffer system. Using this buffer system will not cause any toxic reactions in the human body. CaP coating of the Ti6Al4V surface has been performed in this new SBF. The surface roughness and thickness specifications of the coatings have been determined, their microstructures have been analyzed by using a scanning electron microscope (SEM), the elemental analysis (EDX) of the coating surfaces and the XRD analysis have been done. The results are presented and discussed.
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    Hydroxyapatite Coating on Ti6Al4V Alloy Surface Through Biomimetic Method Using Glycolic Acid - Sodium Gluconate Buffer System and Examination of Properties of the Coating
    Aydin, I; Engin, F
    The use of implant materials is one of the important surgical interventions in the treatment of disorders that are congenital and acquired deformities in musculoskeletal system. Metallic biomaterials within these implant materials are often preferred because of their proximity to the mechanical properties of the bone. In the implantation process, the surfaces of these alloys are coated with ceramic based biomaterials to increase the bioactivity and biocompatibility properties. In this study, it is aimed to create hydroxyapatite (HA) coating that is completely harmonious with human blood plasma environment, on Ti6Al4V alloy, using glycolic acid - sodium gluconate buffer system with biomimetic method for the first time in literature. Coating was realised inside synthetic body fluid (SBF) with waiting periods of 24, 48, 72 and 96 hours. Relating to the coatings, surface smoothness and thickness specifications have been determined, their micro structure has been analysed by Scanning Electron Microscope (SEM), the elementary analyses namely Energy Dispersive X-ray Spectroscopy (EDS) for the surfaces of coating have been determined and X-Ray Diffraction (XRD) analysis have been conducted for obtaining the concentrations of the phases. As a result of the experiments, successful surface smoothness values and ratio of Ca/P close to optimal value have been obtained. Additionally, the presence of HA crystals with intense phase structure, with compact and homogeneous distribution on the substrate have been observed.
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    Investigation of Fracturing and Adhesion Behavior of Hydroxapatite Coating Formed by Aminoacetic Acid-Sodium Aminoacetate Buffer Systems
    Aydin, I; Kirman, M
    Biomaterials utilized in implantation can be categorized into 4 main categories, as ceramics, polymers, metals and composites. Ceramic-based biomaterials are opted for, particularly in the field of orthopedics. These materials, also named as bioceramics, are usually employed by coating them onto the base material, inasmuch as they are far from the mechanical values of bone. In this study, a hydroxyapatite coating that is fully compatible with human blood plasma was applied on Ti6Al4V alloy through a biomimetic technique using aminoacetic acid-sodium aminoacetate buffer system for the first time in the literature, and examinations related thereto were carried out. The surface of the base material Ti6Al4V alloy was activated with various chemicals. Subsequent to activating the surface, a coating process whereby the base material was kept in simulated body fluid for 24, 48, 72, 96 h was carried out. Ultimate microhardness (indentation) tests were performed to determine the average indentation depths in maximum load, vickers hardness and elasticity modulus of the coatings obtained by using the biomimetic method, while scratch tests were performed to measure the surface bonding strengths of the coating layers. Furthermore, the fracture toughness values of the coating were calculated. The results obtained through the study are evaluated and discussed.
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    Effect of Shot Blasting on the Boriding Kinetics of AISI 316L Stainless Steel
    Ayvaz, SI; Aydin, I; Bahcepinar, AI
    In this study, the effect of shot blasting on boriding kinetics of AISI 316L stainless steel alloy was investigated. For this purpose, AISI 316L samples were shot blasted at 6 bar pressure using 300-500 mu m glass beads. Shot blasted samples were borided with powder pack boriding technique, using Ekabor 2 boriding powder, with 2, 4 and 6 boriding times at 850, 900 and 950 degrees C boriding temperatures. As a result of boriding, boride layers consisting of FeB and Fe2B phases with a microhardness of similar to 1497-2135 HV0.1 and an average thickness of similar to 9.6-49.27 mu m were obtained on the surface of AISI 316L stainless steel alloy samples. These boride layers on the AISI 316L stainless steel alloy surface were formed in flat morphology due to the high amount of alloying elements. In the kinetic studies, the activation energy of boron diffusion in AISI 316L stainless steel alloy was calculated as 204.68 kJ mol(-1). The obtained results showed that shot blasting decreased the boron diffusion kinetics compared to the results in the literature.
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    HA Coating on Ti6Al7Nb Alloy Using an Electrophoretic Deposition Method and Surface Properties Examination of the Resulting Coatings
    Aydin, I; Bahçepinar, AI; Kirman, M; Çipiloglu, MA
    Ti and its alloys, which are commonly used in biomedical applications, are often preferred due to their proximity to the mechanical properties of bone. In order to increase the biocompatibility and bioactivities of these materials, biomaterials based on ceramic are used in coating operations. In this study, by using an electrophoretic deposition method, instead of on the Ti6Al4V alloy which is commonly used in the literature, a hydroxyapatite (HA) coating operation was applied on the surface of the Ti6Al7Nb alloy, and the surface properties of the coatings were examined. Ti6Al7Nb is a new-generation implant on which there have not been many studies. The voltage values which were used in the coating operation were 50, 100, 150 and 200 V, and the time parameter was stabilized at 1 min. In our method, when preparing the solution, HA, ethanol, and polyvinyl alcohol (PVA) were used. At the end of the study, by using an electron microscope (SEM) the microstructures of the coatings were examined; elemental analyses (EDS) of the coating surfaces were performed; and by using an X-radiation diffraction (XRD) method, the phases which the coatings contained and the concentration of these phases were determined, and the coating thickness, roughness, and hardness values were also determined. Also, by conducting a Scratch test, the strength of the surface combination was examined. At the end of the study, in each parameter, a successful HA coating was seen. By comparing parameters with each other, the ideal voltage value in this coating was determined. It was determined that the most suitable coating was obtained at 100 V voltage and 1 min deposition time.
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    Surface characterization of EPD coating on AZ91 Mg alloy produced by powder metallurgy
    Aydin, I; Bahçepinar, AI; Gül, C
    Intense implants which are used widely in biomedical applications such as Ti and its alloys and 316 L stainless steel can harm the surrounding tissues, hence may also cause infection. In order to eliminate this risk, it is necessary to produce new generation implant materials that are lighter than their existing biomaterials for use in biomedical applications and whose mechanical properties and structure are close to bone. In this study AZ91 Mg alloy implant material is created by using powder metallurgy method. In addition, in order to improve the bio-compatibility and bio-activity, the generated implant material was also coated with hydroxyapatite (HA) which is known as a ceramic based biomaterial. In this study, AZ91 Mg alloy is created by using powder metallurgy method. HA coating was applied to the alloy surface using the electrophoretic deposition method. The surface properties and corrosion resistance of the coatings made were examined. The applied voltage values in the coating process were determined as 100, 150, 200 and 250 V, the time parameter was stabilized as 2 minutes. HA, ethanol, polyvinyl alcohol (PVA), N, N-Dimethylformamide chemicals were used to prepare the coating solution. At the end of the study, microstructures of the coatings were examined by using scanning electron microscopy (SEM) and elemental analyzes (EDS) of the coating surfaces were performed. The X-ray diffraction method (XRD) was used to determine the phases of the coatings and its concentration. Coating thickness and surface roughness values were also determined. Corrosion behavior of coated samples was determined by potentiodynamic electrochemical potential corrosion test in artificial body fluid.
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    Tribological and adhesion properties of microwave-assisted borided AISI 316L steel
    Ayvaz, SI; Aydin, I
    In this study, AISI 316L stainless steel alloy samples were borided with powder-pack boriding method using Ekabor II powder with the support of a microwave furnace with a power of 2.9 KW and a frequency of 2.45 GHz. Boriding was carried out at 850, 900 and 950 degrees C temperatures for 2, 4 and 6 h of operation. A distinct diffusion barrier consisting of Fe-Ni-Si elements was detected in borided samples at 950 degrees C for 4 and 6 h. As a result of the Daimler Benz Rockwell-C adhesion tests, regions with insufficient adhesion strength were detected in these samples. In other samples, adhesion qualities between boride layers and substrate were in the range of HF1-HF3. The lowest specific wear rates were determined as 5.208 (mm(3) Nm(-1)) x 10(-6) and 5.210 (mm(3) Nm(-1)) x 10(-6) for the samples borided for 6 h at 850 degrees C and 4 h at 900 degrees C, respectively. It was determined that the increase in thickness of the brittle FeB compound increased the wear with the three-body abrasive wear mechanism.
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    Investigation of the effect of shot blasting on the surface properties of the HA coatings processed by the EPD method
    Bahçepinar, AI; Aydin, I
    316L stainless steel implant material surfaces shot blasted with glass beads underwent hydroxyapatite (HA) coating process by electrophoretic deposition method (EPD). The me-chanical and metallographic test results of HA coatings applied to the shot blasted and sanded substrates have been discussed. The sanded process was carried out with 320 Grit SiC sandpa-per. Shot blasted process was carried out in a vacuum shot blasting machine at 5 bar pressure with glass beads. Ethanol was used as a solvent during the coating process. The coating so-lution was prepared by mixing ethanol, HA, PVA, and N, N-Dimethylformamide chemicals in specific ratios to have a steady suspension. Regarding tests conducted on HA coatings, it was revealed that shot blasted surfaces had better results when compared to those of sanded surfaces. Hopefully, this new process for coatings will be a new impression for future studies.
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    A novel method for determining effects of fire damage on the safety of the Type I pressure hydrogen storage tanks
    Ayvaz, M; Ayvaz, SI; Aydin, I
    Consumption of the fossil fuels causes greenhouse gas effect and environmental pollution, which are two basic problems of our age. As a result of this problem, clean and renewable alternative energy sources are beginning to replace fossil fuels. Nowadays, the use of hydrogen energy, which is one of the clean energy, is increasing in transportation and industrial areas. Increasing of hydrogen energy usage, scientists are attempting to solve the many safety problems (such as fire, burst, impact and hydrogen embrittlement) that can occur during the storage and consumption of hydrogen energy. In this study, during the event of fire, the safety of metallic Type I pressure hydrogen storage tanks is investigated by using a novel approach. In this new approach, the mechanical strength drops of the tank materials that is related with temperature rising are added to the safety calculations. In the study, 6061 T6 aluminum and SS 316L stainless steel alloys were used as hydrogen tank material. The safety of hydrogen tanks modelled using these alloys was investigated under different temperature conditions (22, 100, 200 and 300 degrees C) and internal pressure (15, 20 and 25 MPa). (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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    Effect of the Microwave Heating on Diffusion Kinetics and Mechanical Properties of Borides in AISI 316L
    Ayvaz, SI; Aydin, I
    In this study, the effect of microwave heating on boride formation and diffusion kinetics in 316L stainless steel alloys was investigated. Boriding was carried out in microwave furnace with 2.9 kW power and 2.45 GHz frequency. Four different boriding temperatures (800, 850, 900 and 950 degrees C) were used. Boriding was performed for 2, 4 and 6 h for each temperature. Boron layer thicknesses of boride layers were determined by optical microscope. SEM images were taken from the cross sections of the borided samples. Boron activation energy was determined as 244.15 kJ/mol in microwave environment. Two times thicker boride layer was obtained by microwave boriding process compared to the conventional heating process. The mechanical properties of the boride layers formed by microwave boriding (Young's modulus, hardness, yield strength, residual thermal stress) were determined by nanoindentation tests.
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    Sol-gel synthesized Sr4Al14O25:Eu2+/Dy3+ blue-green phosphorous as oxygen sensing materials
    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 pO(2) 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. (C) 2016 Elsevier BM. All rights reserved.
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    Unpublished Mediterranean and Black Sea records of marine alien, cryptogenic, and neonative species
    Ragkousis, M; Zenetos, A; Ben Souissi, J; Hoffman, R; Ghanem, R; Taskin, E; Muresan, M; Karpova, E; Slynko, E; Dagli, E; Fortic, A; Surugiu, V; Macic, V; Trkov, D; Bahri, WR; Tsiamis, K; Ramos-Espla, AA; Petovic, S; Ferrario, J; Marchini, A; Sconfietti, R; Ammar, I; Alo, A; Edelist, D; Begun, T; Teaca, A; Tari, G; Huseyinoglu, MF; Karachle, PK; Dogrammatzi, A; Apostolopoulos, GA; Crocetta, F; Kytinou, E; Digenis, M; Skouradakis, G; Tomas, F; Bariche, M; Kaminas, A; Konida, K; Deidun, A; Marrone, A; Fraschetti, S; Mihneva, V; Bianchi, CN; Morri, C; Gerovasileiou, V; Lipej, L; Sini, M; Mangialajo, L; Zotou, M; Skolka, M; Azzurro, E; Vella, A; Dailianis, T; Grigoriou, P; Jimenez, C; Tsirintanis, K; Oikonomidis, G; Mancini, E; Papadakis, O; Di Martino, V; Chatzigeorgiou, G; Ben Amor, MM; Vernadou, E; Arda, Y; Minasidis, V; Azzola, A; Hadjioannou, L; Montefalcone, M; Baldacchino, Y; Stancanelli, B; Bonifazi, A; Occhipinti-Ambrogi, A; Smeraldo, S; Evans, J; Kondylatos, G; Falautano, M; Castriota, L; Lamprou, A; Rizgalla, J; Mavric, B; Papadimitriou, E; Kersting, DK; Schembri, PJ; Khamassi, F; Nikolaou, A; Ballesteros, E; Dimitriadis, C; García, M; Anastasiadis, A; Kalogirou, S; Nalmpanti, M; Altamirano, M; Grech, D; Mavrouleas, D; Vella, N; Darmanin, SA; Dragicevic, B; Poursanidis, D; Tsatiris, A; Corsini-Foka, M; Orlando-Bonaca, M; Insacco, G; Tsalapatis, A; Scannella, D; Tiralongo, F; Verdura, J; Vitale, S; Valsamidis, MA; Bazairi, H; Mannino, AM; Virgili, R; Coccia, FC; El Zrelli, R; Nikolidakis, S; Rabaoui, LJ; Yapici, S; Zaouali, J; Zava, B; Agrotis, N; Bilecenoglu, M; Çinar, ME; Moraitis, ML; Albano, PG; Kaddouri, N; Kosma, I; Falsone, F; Fossati, V; Geraci, ML; Zamuda, LL; Mancuso, FP; Petrou, A; Resaikos, V; Aydin, I; Batjakas, IE; Bos, AR; El Ouamari, N; Giallongo, G; Kampouris, TE; Ounifi-Ben Amor, K; Dogan, A; Dulcic, J; Okudan, ES; Rilov, G; Rosso, A; Royo, L; Selfati, M; Gaglioti, M; Giakoumi, S; Kousteni, V; Micu, D; Nicoara, M; Orfanidis, S; Papatheodoulou, M; Tempesti, J; Triantaphyllou, M; Tsourou, T; Yalgin, F; Baltag, E; Cerim, H; Filiz, H; Georgiadis, CG; Papadamakis, P; Rammou, DL; Samargiu, MD; Sciuto, F; Sinopoli, M; Türker, A; Chiarore, A; Tamburello, L; Karray, S; Hassen, B; Katsanevakis, S
    To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020-2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia).
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    Gastrostomy in Hospitalized Patients with Acute Stroke: NoroTek Turkey Point Prevalence Study Subgroup Analysis
    Topçuoglu, MA; Özdemir, AÖ; Aykaç, Ö; Milanoglu, A; Gökçe, M; Bavli, S; Çabalar, M; Yayla, V; Erdogan, HA; Özkul, A; Günes, A; Degirmenci, B; Aluçlu, U; Kozak, HH; Güngör, L; Erdogan, M; Acar, ZÖ; Cenikli, U; Kablan, Y; Yilmaz, A; Genç, H; Nazliel, B; Çaglayan, HB; Gencer, ES; Ay, H; Demirbas, H; Akdogan, Ö; Emre, U; Yildiz, ÖK; Bolayir, A; Demir, T; Tanriverdi, Z; Tekan, ÜY; Akpinar, ÇK; Özkan, E; Ilik, F; Sirin, H; Güler, A; Önder, H; Bektas, H; Öcek, L; Bakar, M; Ongun, N; Krespi, Y; Isikay, CT; Aslanbaba, E; Sorgun, M; Gürkas, E; Karadeli, HH; Midi, I; Ilgezdi, I; Bilgiç, AB; Akyol, S; Epçeliden, MT; Atmaca, MM; Kursun, O; Keskin, O; Sirinocak, PB; Baydemir, R; Akçakoyunlu, M; Öztürk, S; Özel, T; Ünal, A; Dora, B; Yürekli, VA; Arlier, Z; Eren, A; Yilmaz, A; Kisabay, A; Acar, B; Bastan, B; Acar, Z; Niflioglu, B; Güven, B; Kaya, D; Afsar, N; Yazici, D; Aytaç, E; Yaka, E; Toplutas, E; Degirmenci, E; Ince, FB; Büyükserbetçi, G; Aydin, I; Çetiner, M; Sen, M; Turgut, N; Kale, N; Çoban, E; Yesilot, N; Ekizoglu, E; Kizek, Ö; Birgili, Ö; Yevgi, R; Kunt, R; Giray, S; Akkas, SY; Senadim, S; Yoldas, T; Asil, T; Duman, T; Atasoy, T; Çinar, BP; Demir, T; Can, U; Ünsal, YÖ; Eskut, N; Aslan, Y; Bas, DF; Sener, U; Yilmaz, Z; Bozdogan, Z; Alioglu, Z; Arsava, EM
    Objective: Nutritional status assessment, dysphagia evaluation and enteral feeding decision are important determinants of prognosis in acute neurovascular diseases. Materials and Methods: NoroTek is a point prevalence study conducted with the participation of 87 hospitals spread across all health sub regions of Turkey conducted on 10-May-2018 (World Stroke Awareness Day). A total of 972 hospitalized neurovascular patients [female: 53%, age: 69 +/- 14; acute ischemic stroke in 845; intracerebral hematoma (ICH) in 119 and post-resuscitation encephalopathy (PRE) in 8] with complete data were included in this sub-study. Results: Gastrostomy was inserted in 10.7% of the patients with ischemic stroke, 10.1% of the patients with ICH and in 50% of the patients with PRE. Independent predictors of percutaneous endoscopic gastrostomy (PEG) administration were The National Institutes of Health Stroke Scale score at admission [exp (ss): 1.09 95% confidence interval (CI): 1.05-1.14, per point] in ischemic stroke; and mechanical ventilation in ischemic [exp (ss): 6.18 (95% CI: 3.16-12.09)] and hemorrhagic strokes [exp (ss): 26.48 (95% CI: 1.36-515.8)]. PEG was found to be a significant negative indicator of favorable (modified Rankin's scale score 0-2) functional outcome [exp (ss): 0.032 (95% CI: 0.004-0.251)] but not of in-hospital mortality [exp (ss): 1.731 (95% CI: 0.785-3.829)]. Nutritional and swallowing assessments were performed in approximately two-thirds of patients. Of the nutritional assessments 69% and 76% of dysphagia assessments were completed within the first 2 days. Tube feeding was performed in 39% of the patients. In 83.5% of them, tube was inserted in the first 2 days; 28% of the patients with feeding tube had PEG later. Conclusion: The NoroTek study provided the first reliable and large-scale data on key quality metrics of nutrition practice in acute stroke in Turkey. In terms of being economical and accurate it makes sense to use the point prevalence method.
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    Atrial Fibrillation Management in Acute Stroke Patients in Türkiye: Real-life Data from the NöroTek Study
    Topçuoglu, MA; Arsava, EM; Özdemir, AÖ; Aykaç, Ö; Çetiner, M; Gencer, ES; Günes, A; Krespi, Y; Yaka, E; Öcek, L; Tanriverdi, Z; Tekan, ÜY; Özkul, A; Özkan, E; Sirin, H; Güler, A; Kursun, O; Kunt, R; Cenikli, U; Acar, B; Kablan, Y; Yilmaz, A; Isikay, CT; Aslanbaba, E; Sorgun, M; Bektas, H; Çabalar, M; Yayla, V; Erdogan, HA; Gökçe, M; Bavli, S; Ongun, N; Keskin, AO; Akdogan, Ö; Emre, U; Yildiz, ÖK; Bolayir, A; Akpinar, ÇK; Karadeli, HH; Özel, T; Ünal, A; Dora, B; Arlier, Z; Eren, A; Milanoglu, A; Nazliel, B; Çaglayan, HB; Güven, B; Erdogan, M; Acar, ZÖ; Bakar, M; Giray, S; Senadim, S; Asil, T; Demir, T; Ünsal, YÖ; Eskut, N; Aslan, Y; Bas, DF; Sener, U; Degirmenci, B; Aluçlu, U; Bastan, B; Acar, Z; Niflioglu, B; Yazici, D; Aytaç, E; Ince, FB; Ay, H; Önder, H; Kozak, HH; Ilgezdi, I; Bilgiç, AB; Akyol, S; Güngör, IL; Atmaca, MM; Sen, M; Yevgi, R; Akkas, SY; Yoldas, T; Atasoy, HT; Çinar, BP; Yilmaz, A; Genç, H; Kisabay, A; Ilik, F; Demirbas, H; Midi, I; Sirinocak, PB; Duman, T; Demir, T; Can, U; Yürekli, VA; Bozdogan, Z; Alioglu, Z; Kaya, D; Afsar, N; Gürkas, E; Toplutas, E; Degirmenci, E; Büyükserbetçi, G; Aydin, I; Epçeliden, MT; Turgut, N; Kale, N; Çoban, E; Yesilot, N; Ekizoglu, E; Kizek, Ö; Bilgili, Ö; Baydemir, R; Akçakoyunlu, M; Yilmaz, Z; Öztürk, S
    Objective: Atrial fibrillation (AF) is the most common directly preventable cause of ischemic stroke. There is no dependable neurology-based data on the spectrum of stroke caused by AF in Turkiye. Within the scope of NoroTek-Turkiye (TR), hospital-based data on acute stroke patients with AF were collected to contribute to the creation of acute-stroke algorithms.Materials and Methods: On May 10, 2018 (World Stroke Awareness Day), 1,790 patients hospitalized at 87 neurology units in 30 health regions were prospectively evaluated. A total of 929 patients [859 acute ischemic stroke, 70 transient ischemic attack (TIA)] from this study were included in this analysis.Results: The rate of AF in patients hospitalized for ischemic stroke/TIA was 29.8%, of which 65% were known before stroke, 5% were paroxysmal, and 30% were diagnosed after hospital admission. The proportion of patients with AF who received effective treatment [international normalization ratio >= 2.0 warfarin or non-vitamin K antagonist oral anticoagulants (NOACs) at a guideline dose] was 25.3%, and, either no medication or only antiplatelet was used in 42.5% of the cases. The low dose rate was 50% in 42 patients who had a stroke while taking NOACs. Anticoagulant was prescribed to the patient at discharge at a rate of 94.6%; low molecular weight or unfractionated heparin was prescribed in 28.1%, warfarin in 32.5%, and NOACs in 31%. The dose was in the low category in 22% of the cases discharged with NOACs, and half of the cases, who received NOACs at admission, were discharged with the same drug.Conclusion: NoroTekTR revealed the high but expected frequency of AF in acute stroke in Turkiye, as well as the aspects that could be improved in the management of secondary prophylaxis. AF is found in approximately one-third of hospitalized acute stroke cases in Turkiye. Effective anticoagulant therapy was not used in three-quarters of acute stroke cases with known AF. In AF, heparin, warfarin, and NOACs are planned at a similar frequency (one-third) within the scope of stroke secondary prophylaxis, and the prescribed NOAC dose is subtherapeutic in a quarter of the cases. Non-medical and medical education appears necessary to prevent stroke caused by AF.
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    Acute Stroke Management in Türkiye: Intravenous Tissue Plasminogen Activator and Thrombectomy NöroTek: Türkiye Neurology Single Day Study
    Topçuoglu, MA; Özdemir, AÖ; Arsava, EM; Günes, A; Aykaç, Ö; Gencer, ES; Çabalar, M; Yayla, V; Erdogan, HA; Erdogan, M; Acar, ZÖ; Giray, S; Kablan, Y; Tanriverdi, Z; Tekan, ÜY; Asil, T; Akpinar, ÇK; Yürekli, VA; Acar, B; Sirin, H; Güler, A; Baydemir, R; Akçakoyunlu, M; Öcek, L; Çetiner, M; Nazliel, B; Çaglayan, HB; Ongun, N; Eren, A; Arlier, Z; Cenikli, U; Gökçe, M; Bavli, S; Yaka, E; Özkul, A; Degirmenci, B; Aluçlu, U; Isikay, CT; Aslanbaba, E; Sorgun, M; Aytaç, E; Ay, H; Kunt, R; Senadim, S; Ünsal, YÖ; Eskut, N; Alioglu, Z; Yilmaz, A; Genç, H; Yilmaz, A; Milanoglu, A; Gürkas, E; Degirmenci, E; Bektas, H; Ilgezdi, I; Bilgiç, AB; Akyol, S; Güngör, L; Kale, N; Çoban, E; Yesilot, N; Ekizoglu, E; Kizek, Ö; Kursun, O; Yildiz, ÖK; Bolayir, A; Kisabay, A; Bastan, B; Acar, Z; Niflioglu, B; Güven, B; Kaya, D; Afsar, N; Yazici, D; Toplutas, E; Özkan, E; Ilik, F; Ince, FB; Büyükserbetçi, G; Önder, H; Karadeli, HH; Kozak, HH; Demirbas, H; Midi, I; Aydin, I; Epçeliden, MT; Atmaca, MM; Bakar, M; Sen, M; Turgut, N; Keskin, O; Akdogan, Ö; Emre, U; Bilgili, Ö; Sirinocak, PB; Yevgi, R; Akkas, SY; Yoldas, T; Duman, T; Özel, T; Ünal, A; Dora, B; Atasoy, T; Çinar, BP; Demir, T; Demir, T; Can, U; Aslan, Y; Bas, DF; Sener, U; Yilmaz, Z; Bozdogan, Z; Özdemir, G; Krespi, Y; Öztürk, S
    Objective: To reveal the profile and practice in patients with acute stroke who received intravenous tissue plasminogen activator (IV tPA) and/or neurointerventional therapy in Turkiye. Materials and Methods: On World Stroke Awareness Day, May 10, 2018, 1,790 patients hospitalized in 87 neurology units spread over 30 health regions were evaluated retrospectively and prospectively. Results: Intravenous tPA was administered to 12% of 859 cases of acute ischemic stroke in 45 units participating in the study. In the same period, 8.3% of the cases received neurointerventional treatment. The rate of good prognosis [modified Rankin score (mRS) 0-2] at discharge was 46% in 83 patients who received only IV tPA [age: 67 +/- 12 years; National Institutes of Health Stroke Scale (NIHSS): 12 +/- 6; hospital stay, 24 +/- 29 days]; 35% in 51 patients who underwent thrombectomy (MT) alone (age: 64 +/- 13 years; NIHSS: 14.1 +/- 6.5; length of hospital stay, 33 +/- 31 days), 19% in those who received combined treatment (age: 66 +/- 14 years; NIHSS: 15.6 +/- 5.4; length of hospital stay, 26 +/- 35 days), and 56% of 695 patients who did not receive treatment for revascularization (age: 70 +/- 13 years; NIHSS: 7.6 +/- 7.2; length of hospital stay, 21 +/- 28 days). The symptom-to-door time was 87 +/- 53 minutes in the IV treatment group and 200 +/- 26 minutes in the neurointerventional group. The average door-to-needle time was 66 +/- 49 minutes in the IV tPA group. In the neurothrombectomy group, the door-to-groin time was 103 +/- 90 minutes, and the TICI 2b-3 rate was 70.3%. In 103 patients who received IV tPA, the discharge mRS 0-2 was 41%, while the rate of mRS 0-1 was 28%. In 71 patients who underwent neurothrombectomy, the mRS 0-2 was 31% and mRS 0-1 was 18%. The door-to-groin time was approximately 30 minutes longer if IV tPA was received (125 +/- 107 and 95 +/- 83 minutes, respectively). Symptomatic bleeding rates were 4.8% in IV recipients, 17.6% among those who received only MT, and 15% in combined therapy. Globally, the hemorrhage rate was 6.8% in patients receiving IV tPA and 16.9% in MT. Conclusion: IV thrombolytic and neurointerventional treatment applications in acute ischemic stroke in Turkiye can provide the anticipated results. Heterogeneity has begun to be reduced in our country with the dissemination of the system indicated by the Directive on Health Services to be Provided to Patients with Acute Stroke.

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