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Production of CuAlO2 in powder, bulk and nanofiber forms
Ismail Cihan KAYA 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.5
A study was carried out on the production of CuAlO2 by using 3 different production routes namely, hydrothermal synthesis, conventional solid state reaction and electrospinning process. For hydrothermal synthesis, commercially available metal salts, Cu2O powder and chemically precipitated CuO nanoparticles were used as precursors. Bulk CuAlO2 samples were prepared via solid state reaction route by ball milling and high temperature sintering of CuO and Al2O3 powders. CuAlO2 ceramic mats were synthesized by electrospinning process with the assistance of polyvinylpyrolidone, as a template polymer. Highly crystalline mesh structured fibers were obtained after sintering of polymer/equal moles of copper chloride and aluminum nitrate composite in air. In the current work, solid state reaction and electrospinning processes yielded phase pure CuAlO2 in hexagonal symmetry. On the other hand, products obtained from hydrothermal synthesis were CuO, Cu2O and Al(OOH), which did not yield CuAlO2 under current experimental conditions. Detailed qualitative X-ray diffraction analysis revealed the need of specific ionic species in the solution within a narrow temperature-composition-pH window to obtain phase pure CuAlO2 employing hydrothermal conditions.
A Newborn with Gastric Hemangioma Treated Using Propranolol
Kaya, Huseyin,Gokce, Ismail Kursad,Gungor, Sukru,Turgut, Hatice,Ozdemir, Ramazan The Korean Society of Pediatric Gastroenterology 2018 Pediatric gastroenterology, hepatology & nutrition Vol.21 No.4
Gastric hemangiomas are rare benign vascular tumors that can cause severe gastrointestinal system bleeding. We presented the case of a neonate with fresh bleeding and melena from the orogastric tube and detected gastric hemangioma in esophagogastroduodenoscopic examination. Propranolol is widely used in treatment of cutaneous hemangiomas and non-gastric gastrointestinal system hemangiomas. However, the surgical approach is preferred for treating gastric hemangiomas, and there are few reports of gastric hemangiomas associated with non-surgical treatment. Gastric hemorrhage decreased with antacid and somatostatin treatment. Propranolol treatment was initiated before the surgery decision. After three weeks of treatment, we observed regression in the hemangioma with endoscopic evaluation. During the course of treatment, the patient's gastrointestinal system bleeding did not recur, and there were no side effects associated with propranolol.
A Newborn with Gastric Hemangioma Treated Using Propranolol
Huseyin Kaya,Ismail Kursad Gokce,Sukru Gungor,Hatice Turgut,Ramazan Ozdemir 대한소아소화기영양학회 2018 Pediatric gastroenterology, hepatology & nutrition Vol.21 No.4
Gastric hemangiomas are rare benign vascular tumors that can cause severe gastrointestinal system bleeding. We presented the case of a neonate with fresh bleeding and melena from the orogastric tube and detected gastric hemangioma in esophagogastroduodenoscopic examination. Propranolol is widely used in treatment of cutaneous hemangiomas and non-gastric gastrointestinal system hemangiomas. However, the surgical approach is preferred for treating gastric hemangiomas, and there are few reports of gastric hemangiomas associated with non-surgical treatment. Gastric hemorrhage decreased with antacid and somatostatin treatment. Propranolol treatment was initiated before the surgery decision. After three weeks of treatment, we observed regression in the hemangioma with endoscopic evaluation. During the course of treatment, the patient’s gastrointestinal system bleeding did not recur, and there were no side effects associated with propranolol.
On Pseudo Null Bertrand Curves in Minkowski Space-time
Gok, Ismail,Nurkan, Semra Kaya,Ilarslan, Kazim Department of Mathematics 2014 Kyungpook mathematical journal Vol.54 No.4
In this paper, we prove that there are no pseudo null Bertrand curve with curvature functions $k_1(s)=1$, $k_2(s){\neq}0$ and $k_3(s)$ other than itself in Minkowski spacetime ${\mathbb{E}}_1^4$ and by using the similar idea of Matsuda and Yorozu [13], we define a new kind of Bertrand curve and called it pseudo null (1,3)-Bertrand curve. Also we give some characterizations and an example of pseudo null (1,3)-Bertrand curves in Minkowski spacetime.
Sustainable production of acrolein over highly stable and selective WO3 over SiO2-TiO2 catalysts
Boz Ismail,Boroglu Mehtap Safak,Zengin Yasar,Kaya Busra 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.8
The effects of the addition of colloidal silica (cSiO2) and solvents used in the catalyst preparation on the activity and stability of WO3-TiO2 catalysts are reported in this paper. The highly stable and selective WO3 supported cSiO2-TiO2 catalysts were prepared and tested in the vapor-phase glycerol oxy-dehydration. WO3-TiO2 catalysts with and without cSiO2 were characterized by XRD, SEM, NH3-TPD, infrared spectroscopy of pyridine (FTIR-Py), XPS, RAMAN, and N2 adsorption-desorption (BET). The highest medium strength acidity and optimum Brønsted to Lewis acid site ratio of WO3 catalysts were achieved upon the addition of colloidal silica (cSiO2) onto TiO2 support. The medium strength acidity of Brønsted acid sites was responsible for the improved acrolein selectivity and stability. The other major factors in glycerol conversion and acrolein selectivity were the glycerol content and liquid hourly space velocity. The yield to acrolein was up to 70% and kept almost constant in a 50 h continuous run at 300 °C. The gradual decrease in glycerol conversion was due to the build-up of oxygen-containing carbonaceous materials deposited on the catalyst surface.
Gulhan Cakır,Seyfettin Gumus,Ergun Ucar,Hatice Kaya,Ergun Tozkoparan,Emin Ozgur Akgul,Bulent Karaman,Omer Deniz,Ismail Kurt,Metin Ozkan,Hayati Bilgic 대한진단검사의학회 2012 Annals of Laboratory Medicine Vol.32 No.3
Background: Chitotriosidase is an accepted marker of macrophage activation. In this study, we investigated serum chitotriosidase levels in pulmonary tuberculosis (PTB). Methods: Forth-two patients with PTB and 30 healthy subjects were enrolled in the study. The radiological extent of PTB, radiological sequela after treatment, and the degree of smear positivity were assessed. Chitotriosidase levels were measured by a fluorometric method. Results: The serum chitotriosidase levels of the PTB patients were significantly higher than those of the control subjects (39.73±24.97 vs. 9.63±4.55 nmol/mL/h, P<0.001). After completion of the standard 6-month antituberculous treatment, chitotriosidase levels in PTB patients significantly decreased (10.47±4.54 nmol/mL/h, P<0.001). Chitotriosidase levels correlated significantly with the radiological extent of PTB, degree of smear positivity, and post-treatment radiological sequela score (r=0.439, r=0.449, and r=0.337, respectively). Conclusions: This study demonstrated that serum chitotriosidase levels increase in PTB; therefore, chitotriosidase can be used as a marker of disease activity, severity, and response to treatment. Background: Chitotriosidase is an accepted marker of macrophage activation. In this study, we investigated serum chitotriosidase levels in pulmonary tuberculosis (PTB). Methods: Forth-two patients with PTB and 30 healthy subjects were enrolled in the study. The radiological extent of PTB, radiological sequela after treatment, and the degree of smear positivity were assessed. Chitotriosidase levels were measured by a fluorometric method. Results: The serum chitotriosidase levels of the PTB patients were significantly higher than those of the control subjects (39.73±24.97 vs. 9.63±4.55 nmol/mL/h, P<0.001). After completion of the standard 6-month antituberculous treatment, chitotriosidase levels in PTB patients significantly decreased (10.47±4.54 nmol/mL/h, P<0.001). Chitotriosidase levels correlated significantly with the radiological extent of PTB, degree of smear positivity, and post-treatment radiological sequela score (r=0.439, r=0.449, and r=0.337, respectively). Conclusions: This study demonstrated that serum chitotriosidase levels increase in PTB; therefore, chitotriosidase can be used as a marker of disease activity, severity, and response to treatment.
Biomechanical Properties of the Cranial Dura Mater with Puncture Defects : An In Vitro Study
Aydin, Hasan Emre,Kizmazoglu, Ceren,Kaya, Ismail,Husemoglu, Bugra,Sozer, Gulden,Havitcioglu, Hasan,Arslantas, Ali The Korean Neurosurgical Society 2019 Journal of Korean neurosurgical society Vol.62 No.4
Objective : The primary aim of this investigation was to explore the nature of dura mater biomechanics following the introduction of puncture defect(s). Methods : Twenty-eight dura mater specimens were collected during autopsy from the department of forensic medicine of the authors' institution. Specimens were divided randomly into one of four groups : group I (cranial dura mater; n=7), group II (cranial dura mater with one puncture defect; n=7); group III (cranial dura mater with two puncture defects; n=7), and group IV (cranial dura mater with three puncture defects; n=7). Results : The mean${\pm}$standard deviation tensile strengths of the dura mater were $8.35{\pm}3.16$, $8.22{\pm}3.32$, $7.13{\pm}1.77$, and $6.94{\pm}1.93MPa$ for groups I, II, III, and IV, respectively. There was no statistical difference between all groups. A single, two or more punctures of the dura mater using a 20-gauge Quincke needle did not affect cranial dura tensile strength. Conclusion : This biomechanical study may contribute to the future development of artificial dura mater substitutes and medical needles that have a lower negative impact on the biomechanical properties of dura mater.
Kalemci, Orhan,Aydin, Hasan Emre,Kizmazoglu, Ceren,Kaya, Ismail,Yilmaz, Hulya,Arda, Nuri M The Korean Neurosurgical Society 2017 Journal of Korean neurosurgical society Vol.60 No.3
Objective : The aim of this study to investigate the normal values of erythropoietin (EPO) and neuroprotective effects of quercetin and mannitol on EPO and hematocrit levels after acute severe traumatic brain injury (TBI) in rat model. Methods : A weight-drop impact acceleration model of TBI was used on 40 male Wistar rats. The animals were divided into sham (group I), TBI (group II), TBI+quercetin (50 mg/kg intravenously) (group III), and TBI+mannitol (1 mg/kg intravenously) (group IV) groups. The malondialdehyde, glutathione peroxidase, catalase, EPO, and hematocrit levels were measured 1 and 4 hour after injury. Two-way repeated measures analysis of variance and Tukey's test were used for statistical analysis. Results : The malondialdehyde levels decreased significantly after administration of quercetin and mannitol compared with those in group II. Catalase and glutathione peroxidase levels increased significantly in groups III and IV. Serum EPO levels decreased significantly after mannitol but not after quercetin administration. Serum hematocrit levels did not change significantly after quercetin and mannitol administration 1 hour after trauma. However, mannitol administration decreased serum hematocrit levels significantly after 4 hour. Conclusion : This study suggests that quercetin may be a good alternative treatment for TBI, as it did not decrease the EPO levels.
Kizmazoglu, Ceren,Aydin, Hasan Emre,Kaya, Ismail,Atar, Murat,Husemoglu, Bugra,Kalemci, Orhan,Sozer, Gulden,Havitcioglu, Hasan The Korean Neurosurgical Society 2019 Journal of Korean neurosurgical society Vol.62 No.6
Objective : The aim of this study was to investigate the biomechanical differences between human dura mater and dura mater substitutes to optimize biomimetic materials. Methods : Four groups were investigated. Group I used cranial dura mater (n=10), group II used $Gore-Tex^{(R)}$ Expanded Cardiovascular Patch (W.L. Gore & Associates Inc., Flagstaff, AZ, USA) (n=6), group III used $Durepair^{(R)}$ (Medtronic Inc., Goleta, CA, USA) (n=6), and group IV used $Tutopatch^{(R)}$ (Tutogen Medical GmbH, Neunkirchen am Brand, Germany) (n=6). We used an axial compression machine to measure maximum tensile strength. Results : The mean tensile strengths were $7.01{\pm}0.77MPa$ for group I, $22.03{\pm}0.60MPa$ for group II, $19.59{\pm}0.65MPa$ for group III, and $3.51{\pm}0.63MPa$ for group IV. The materials in groups II and III were stronger than those in group I. However, the materials in group IV were weaker than those in group I. Conclusion : An important dura mater graft property is biomechanical similarity to cranial human dura mater. This biomechanical study contributed to the future development of artificial dura mater substitutes with biomechanical properties similar to those of human dura mater.