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Öğe A comparative study on fabrication of Cu2ZnSnS4 (CZTS) nanofibers using acetate and chloride metal precursors(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2015) Buyukbekar, Burak Zafer; Ozel, Faruk; Sakalak, Huseyin; Cavusoglu, Halit; Ersoz, Mustafa; Kus, Mahmut; Yavuz, Mustafa SelmanThis study reports, for the first time, the fabrication of electrospun Cu2ZnSnS4 (CZTS) nanofibers using metal acetate precursors. Viscous poly(vinyl pyrrolidone) (PVP) solution containing acetate or chloride salts of copper, zinc, and tin was electrospun onto a conductive substrate. The PVP nanofibers that have a mixture of metal salts were annealed at elevated temperatures. After calcination, these nanofibers were treated with the sulfur source and then annealed again in order to generate CZTS nanofibers. The CZTS nanofibers generated from acetate and chloride salts were characterized and compared. Belt-like and wire-like nanofibers were obtained when using metal acetate and chloride precursors, respectively.Öğe Disulfide-linked triazine based porous polymer networks for CO2 capture(AMER CHEMICAL SOC, 2016) Goren, Ekrem; Cavusoglu, Halit; Yavuz, Mustafa Selman[Abstract not Available]Öğe Efficient CO2 adsorption by disulfide-linked covalent organic polymers(AMER CHEMICAL SOC, 2016) Goren, Ekrem; Cavusoglu, Halit; Yavuz, Mustafa Selman[Abstract not Available]Öğe Efficient removal of toxic cationic dyes from wastewater using disulfide-linked porous polymer networks(AMER CHEMICAL SOC, 2015) Atas, Mehmet Sahin; Cavusoglu, Halit; Ozkaya, Aysenur; Yavuz, Mustafa Selman[Abstract not Available]Öğe Gold nanoparticles immobilized on electrospun titanium dioxide nanofibers for catalytic reduction of 4-nitrophenol(WILEY-V C H VERLAG GMBH, 2017) Cavusoglu, Halit; Buyukbekar, Burak Zafer; Sakalak, Huseyin; Kohsakowski, SebastianThis study involves the preparation and catalytic properties of anatase titanium dioxide nanofibers (TiO2 NFs) supported gold nanoparticles (Au NPs) using a model reaction based on the reduction of 4-nitrophenol (NP) into 4-aminophenol (AP) by sodium borohydride (NaBH4). The fabrication of surfactant-free Au NPs was performed using pulsed laser ablation in liquid (PLAL) technique. The TiO2 NFs were fabricated by a combination of electrospinning and calcination process using a solution containing poly(vinyl pyrolidone)(PVP) and titanium isopropoxide. The adsorption efficiency of laser-generated surfactant-free Au NPs to TiO2 NF supports as a function of pH was analyzed. Our results show that the electrostatic interaction mainly controls the adsorption of the nanoparticles. Au NPs/TiO2 NFs composite exhibited good catalytic activity for the reduction of 4-NP to 4-AP. The unique combination of these materials leads to the development of highly efficient catalysts. Our heterostructured nanocatalysts possibly form an efficient path to fabricate various metal NP/metal-oxide supported catalysts. Thus the applications of PLAL-noble metal NPs can widely broaden.Öğe Investigation of absorption characteristics of fetal bovine serum (FBS) due to interaction with continuum VIS-NIR laser(AMER CHEMICAL SOC, 2014) Cavusoglu, Halit; Yavuz, Mustafa Selman; Yilmaz, Mehmet Fatih[Abstract not Available]Öğe Measuring Temperature Change at the Nanometer Scale on Gold Nanoparticles by Using Thermoresponsive PEGMA Polymers(WILEY-V C H VERLAG GMBH, 2017) Yavuz, Mustafa S.; Citir, Murat; Cavusoglu, Halit; Demirel, GokhanPlasmonic heating of gold nanoparticles (AuNPs) under laser illumination is a highly desirable technique, especially for cancer therapy. However, significant drawbacks still remain including uncontrolled heat release from AuNPs, random exposure duration, and selection of the proper laser power without damaging normal healthy cells. Herein, we demonstrate a simple and versatile method to measure temperature variation on the surface of Au nanoparticles under laser irradiation based on a thermoresponsive polymer, poly(ethylene glycol) methylether methacrylate (PEGMA). In this context, a series of PEGMA polymers were synthesized to have different lower critical solution temperature (LCST) values (28-90 degrees C) and conjugated to the surface of spherical AuNPs by a gold-thiolate linkage. According to our strategy, the AuNPs first photothermally absorb light energy and convert it to heat owing to their tailored photothermal characteristics. The generated heat from the AuNPs subsequently dissipates into the surrounding thermoresponsive PEGMA polymer. When the temperature generated on the Au surface upon laser irradiation for a certain exposure time reaches the LCST value of the surrounding PEGMA polymer, the polymer chain collapses. Therefore, the hydrodynamic diameter of the PEGMA-coated AuNPs changes, which can be easily monitored by using dynamic light scattering (DLS). We systematically measured the temperature (28-90 degrees C) generated on the AuNP surfaces by using different laser power densities with varying durations. We believe that the resulting strategy will be very valuable for oncologists to easily predict the minimum laser power and duration needed to destroy the cancer cells through the photothermal effect of Au nanostructures.Öğe Measuring temperature change on photothermal Au nanorod and nanocage upon laser irradiation(AMER CHEMICAL SOC, 2015) Cavusoglu, Halit; Sakalak, Huseyin; Buyukbekar, Burak Zafer; Demirel, Gokhan; Citir, Murat; Yavuz, Mustafa Selman[Abstract not Available]Öğe New method for measuring the temperature change of photothermal Au nanostructures using smart polymers(AMER CHEMICAL SOC, 2015) Cavusoglu, Halit; Sakalak, Huseyin; Buyukbekar, Burak Zafer; Demirel, Gokhan; Citir, Murat; Yavuz, Mustafa Selman[Abstract not Available]Öğe Novel capsules for potential theranostics of obscure gastrointestinal bleedings(CHURCHILL LIVINGSTONE, 2016) Colak, Bayram; Sakalak, Huseyin; Cavusoglu, Halit; Yavuz, Mustafa SelmanObscure gastrointestinal (GI) bleeding is identified as persistent or repeated bleeding from the gastrointestinal tract which could not be defined by conventional gastrointestinal endoscopy and radiological examinations. These GI bleedings are assessed through invasive diagnostic and treatment methods including enteroscopy, angiography and endoscopy. In addition, video capsule endoscopy (VCE) is a non-invasive method used to determine the location of the bleeding, however, this does not provide any treatment. Despite of these successful but invasive methods, an effective non-invasive treatment is desperately needed. Herein, we prepare non-invasive theranostic capsules to cure obscure GI bleeding. An effective theranostic capsule containing endothelin as the targeting agent, thrombin-fibrinogen or fibrin as the treating agent, and fluorescein dye as the diagnostic tool is suggested. These theranostic capsules can be administered orally in a simple and non-invasive manner without a risk of complication. By using these novel capsules, one can diagnose obscure GI bleeding with having a possibility of curing. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Novel method based on photothermal cleavage of thermolabile molecules on Au nanoparticles for controlled release(AMER CHEMICAL SOC, 2016) Goren, Ekrem; Cavusoglu, Halit; Yavuz, Emine; Usta, Hakan; Citir, Murat; Yavuz, Mustafa Selman[Abstract not Available]Öğe Novel photothermal-based release mechanism for controlled release on Au nanoparticles through light(AMER CHEMICAL SOC, 2015) Goren, Ekrem; Cavusoglu, Halit; Yavuz, Emine; Usta, Hakan; Yavuz, Mustafa Selman[Abstract not Available]Öğe Structural, morphological and optical studies of nanostructured cadmium oxide films: the role of pH(SPRINGER, 2018) Cavusoglu, HalitIn this work, nanocrystalline cadmium oxide (CdO) films were deposited on glass substrates for various pH values ranging from 11.3 to 12.5 by successive ionic layer adsorption and reaction (SILAR) technique. To obtain good film stoichiometry, the annealing of films in static air at a temperature of 623 K for 1 h was carried out. The comparison of structural, morphological and optical properties of CdO films at different pH of the solution has been studied. The effects of pH on the crystal structures, the orientation of crystallization and crystallite sizes i.e., structural properties of the films were analyzed with X-ray diffraction (XRD). XRD analysis revealed the polycrystalline nature of the CdO films with cubic structure and show preferential orientation along (111) and (200) planes. The surface morphology of the prepared films having different pH values was investigated by scanning electron microscope (SEM). The optical band gap of nanocrystalline CdO films at different pH has been measured using Ultraviolet-Visible (UV-Vis) spectroscopy. The optical properties showed that a significant reduction in the optical band gap is observed from 3.26 to 2.35 eV by increasing the pH value of the solutions from 11.3 to 12.5, respectively.Öğe Synthesis and characterization of thiol-ene based nanoporous covalent organic polymers for CO2 capture(AMER CHEMICAL SOC, 2016) Buyukbekar, Burak Zafer; Cavusoglu, Halit; Goren, Ekrem; Yavuz, Mustafa Selman[Abstract not Available]Öğe Synthesis of biocompatible thermoresponsive PEGMA nanoparticles for dual release(AMER CHEMICAL SOC, 2015) Yavuz, Emine; Ulasan, Mehmet; Cavusoglu, Halit; Cengeloglu, Yunus; Yavuz, Mustafa Selman[Abstract not Available]
