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Öğe Synthesis, characterization and in vitro cytotoxic activity of platinum(II) oxalato complexes involving 2-substitutedimidazole or 2-substitutedbenzimidazole derivatives as carrier ligands(Istanbul Univ, Fac Pharmacy, 2023) Ertuğrul, Emine Merve; Özçelik, Azime Berna; Çerçi, Nebahat Aytuna; Açık, Leyla; Utku, SemraBackground and Aims: Cisplatin is currently one of the most widely used anticancer drugs in the world. However, its clinical usefulness has frequently been limited by severe side effects, such as nephrotoxicity, ototoxicity and neurotoxicity. Therefore, platinum(II) oxalato complexes with substitute imidazole or benzimidazole carrier ligands were synthesized and their cytotoxic effects were investigated against non-small cell lung cancer (H1299) and human colon adenocarcinoma (CaCo-2), and mouse fibroblast cells lines (L929).Methods: Four platinum(II) complexes, [Pt(L1-L4)2(oxalate)] were synthesized and characterized by FT-IR, 1H NMR and elemental analyses. The MTT method was used to determine the potential antiproliferative effect of synthesized platinum(II) complexes and positive controls.Results: In this study, the cytotoxic activity of platinum(II) complexes against tested cell lines was assessed, with moderate IC50 values. According to IC50 values, Complex 5 with 2-ethylbenzimidazole ligand was found to be the most active complex against H1299 and CaCo-2 cell lines. In general, the compounds are also promising drug candidates for H1299 cell lines with very low activity against the CaCo-2 cell lines.Conclusion: Further modification and development of Complex 4 and 5 derivatives and in vitro cytotoxic activity studies against different cancer cell lines may lead to the emergence of new anticancer agents in the near future.Öğe Efficient removal of cationic dyes from aqueous solutions using a modified poly(ethylene terephthalate) fibers adsorbent(TAYLOR & FRANCIS INC, 2020) Unlu, Nuri; Gunay, Kubra; Arslan, MetinA novel adsorbent was synthesized through functionalization of glycidyl methacrylate-g-poly(ethylene terephthalate) (GMA-g-PET) fibers with iminodiacetic acid (IDA) to give IDA-GMA-g-PET fibers. This adsorbent was then exploited for the removal of Malachite Green (MG) and Rhodamine B (RB) dyes. MG has shown faster adsorption kinetics and equilibrium was attained in 15 mins. and 90 mins. for MG and RB, respectively. IDA-GMA-g-PET fibers showed 100% removal efficiency for MG and RB dyes from the solutions having initial concentrations of 300 mg L(-1)and 200 mg L-1, respectively. Desorption conditions of dyes and reusability of the fibers were also investigated.Öğe Electronic, Elastic, Vibrational and Thermodynamic Properties of HfIrX (X = As, Sb and Bi) Compounds: Insights from DFT-Based Computer Simulation(SPRINGER, 2020) Arikan, Nihat; Dikici Yildiz, Gokcen; Yildiz, Yasin Gokturk; Iyigor, AhmetAb-initio calculations were performed to reveal and thoroughly understand the structural, electronic, elastic, thermodynamic and vibrational properties of HfIrX (X = As, Sb and Bi) compounds in the C1(b) phase. Basic physical characteristics, such as bulk modulus, pressure derivative of bulk modulus, anisotropy factor, shear modulus, Poisson's ratio, Cauchy pressure, elastic constants and Young's modulus were obtained and some of them were compared with those in the literature. Electronic band structure, the density of states and phonon dispersion curves were obtained and compared with current theoretical calculations. It was concluded according to current band structure calculations that the HfIrAs and HfIrBi compounds showed semimetal characteristics, while the HfIrSb compound behaves as a semiconductor. It was determined based on phonon calculations that all three compounds were dynamically stable. Various thermodynamic properties, such as heat capacity, thermal expansion coefficient values and Gruneisen parameter were calculated under constant volume and constant pressure by using Gibbs2 code within the Quasi-harmonic approach, and these results are discussed.Öğe Exchange bias effect revealed by irreversible structural transformation between the HCP and FCC structures of Cobalt nanoparticles(TAYLOR & FRANCIS LTD, 2020) Yildiz, Yasin GokturkIn this study, the exchange bias effect (EBE) revealed by the HCP-FCC structural phase transformation in Cobalt nanoparticles (CoNPs) are modeled and investigated by using the Ising model within the framework of the Effective Field Theory developed by Kaneyoshi. CoNPs are mixed (indistinguishable HCP and FCC) phase at T < 0.36 and T > Tc-FCC. For the non-structural transformation, CoNPs exhibit no exchange bias effect (H-EB = 0.0) and they have normal symmetric coercive field points. But, they have asymmetric coercive field points and they have an exchange bias field for the HCP -> FCC transformation or the inverse (HCP <- FCC). Additionally, an intersection point (Hi) revealed by EBE is obtained between the irreversible M-H curve of the FCC and HCP phase (Hi = Hc1(FCC) = -0.39 and -0.13). Our results show that the exchange bias effect strongly depends on their irreversible structural phase transformations in the materials.Öğe Investigation of the Mechanical, Electronic and Phonon Properties of X2ScAl (X = Ir, Os, and Pt) Heusler Compounds(KOREAN PHYSICAL SOC, 2020) Arikan, Nihat; Ocak, Hamza Yasar; Yildiz, Gokcen Dikici; Yildiz, Yasin Gokturk; Unal, RahmiIn the present study, the second-order elastic constants and the electronic band structures of the X2ScAl (x= Ir, Os, and Pt) compounds crystallized in the L2(1)phase were calculated separately by using theab-initiodensity functional theory. According to the results for the second-order elastic constants, these compounds met the Born mechanical stability criteria. Also, according to the Pugh criteria, they were found to have a ductile structure and to show anisotropic behavior. The microhardneses of the compounds were between 2 and 14 GPa, and the highest hardness was found in the Ir2ScAl (14.290 GPa) compound. In addition, the energy band structures of these compounds were calculated, and the crystals were found to have a metallic bond structure. All the computed data were compared with previously calculated results obtained with different methods. According to the findings obtained in the present study, in terms of its mechanical and electronic behaviors, Ir2ScAl was found to have better physical properties than Os2ScAl and Pt2ScAl. The phonon dispersion curves and their corresponding total and projected densities of states were investigated for the first time by using a linear-response approach in the context of density functional perturbation theory. The frequencies of the optical phonon modes of all compounds at the Gamma point were 4.767, 7.504 and 9.271 THz for Ir2ScAl, 2.761, 7.985 and 9.184 THz for Os2ScAl and 2.012, 5.6952 and 8.118 THz for Pt2ScAl. The heat capacityC(v)at constant volume versus temperature was calculated using a quasi-harmonic approach and the results are discussed.Öğe First-Principles Study on PdMnSn and PtMnSn Compounds inC1(b)Structure(PLEIADES PUBLISHING INC, 2020) Arikan, Nihat; Yildiz, Yasin Gokturk; Yildiz, Gokcen DikiciThe phase stability, the electronic, mechanic and lattice dynamical properties ofC1(b)-type PdMnSn and PtMnSn compounds were investigated using first principles density functional calculations within the generalized gradient approximation. The computed lattice constants of PdMnSn and PtMnSn compounds were in line with the experimental and theoretical data in the published literature. The elastic constants in theC1(b)structure for PdMnSn and PtMnSn compounds were carried out using the energy-strain method. The computed values of three independent elastic constants, both compounds are mechanically stable in theC1-type crystal structure and met the stability criteria. The electronic structure, total and partial density values of states, and total magnetic moment of these compounds were calculated and the evaluations were carried out by comparing with the existing results. Dynamic properties of PdMnSn and PtMnSn compounds were obtained using the density functional perturbation theory. Both of the compounds were dynamically stable due to the absence of the imaginary phonon frequencies. In addition, it was found that the compounds had a rapid rise in specific heat capacities from 0 to 300 K.Öğe Prediction of the Bain spin memory materials (BSMM) revealed by Kaneyoshi theory(TAYLOR & FRANCIS LTD, 2020) Saatci, Buket; Sarli, Numan; Dagdemir, Yilmaz; Yildiz, Yasin Gokturk; Ocak, Hamza YasarIn this work, we investigate the spin transformation from ferromagnetic austenite BCT lattice to antiferromagnetic martensite BCC lattice (j(i) = +J -> j(i) = -J or up arrow up arrow ->up arrow down arrow) in Bain transformation (or Bain strain) by using effective field theory which is developed by Kaneyoshi. We find that the spin orientation changes the magnetic properties in the Bain BCT -> BCC transformation. Therefore, we predict that material can memory their spin orientations in the austenite-martensite transformation similar to the shape memory effect in the shape memory materials. Since the austenite-martensite transformation mechanism is first modelled by Bain, we call this spin memory effect as 'Bain spin memory materials (BSMM)'.Öğe Magnetic properties of the Martensitic transformations with twinned and detwinned(Elsevier Science Bv, 2019) Sarli, Numan; Yildiz, Gokcen Dikici; Yildiz, Yasin Gokturk; Yagci, Nermin KahveciThe effects of the Austenite (A), twinned Martensite (TM) and detwinned Martensite (DTM) structural transformations on the ferromagnetic properties are investegated by means of the effective field theory developed by Kaneyoshi. We find that the critical Curie temperature of the A, TM and DTM is obtained as T-c(A) < T-c(DTM)< T-c(TM) for H = 0. Thermal magnetization loops are obtained for H not equal 0. The area of the thermal magnetization loops of the A-TM is wider than those of the A-DTM. Paramagnetic Austenite has a phase transition from paramagnetic (PM) phase to ferromagnetic (FM) phase at T-c(TM) and T-c(DTM). The temperature of the As (Austenite start), TMf (twinned Martensite finish) and DTM f (detwinned Martensite finish) increase as the external magnetic field (H) increases. The magnetizations of the A, TM and DTM are the same at low temperature (T < A(s)). The coercive field points are obtained as H-c(A) < H-c(DTM)< H-c(TM). The shearing angle plays very important role in the structural transformations and their ferromagnetic properties, especially in TM.Öğe Application of 4-VP-g-PET fibers and its N-oxide derivative as an adsorbent for removal of cationic dye(Springer, 2019) Metin, Arslan; Kubra, GunayPoly(ethylene terephthalate) fibers (PET) were grafted with 4-vinyl pyridine (4-VP) by a chemical grafting technique, and an N-oxide derivative was synthesized (N-oxide-4-VP-g-PET). The removal of methylene blue (MB) from the aqueous solutions by this material was investigated. The removal and desorption capacities for MB dye were studied under various conditions.4-VP-g-PET fibers exhibited a very low removal rate when compared to the basic dye; however, N-oxide-4-VP-g-PET fibers showed more increased removal results. 2.5% of the MB dyes removal was observed with 4-VP-g-PET fibers, while 100% of MB dyes removal was found with N-oxide-4-VP-g-PET fibers using 10ppm of MB solution. Removal capacity of N-oxide-4-VP-g-PET fibers increased with increasing pH values. The maximum removal capacity of MB dye on the N-oxide-4-VP-g-PET fibers was found to be 35.1mgg(-1) at 250ppm. Results showed that removal capacity of 4-VP-g-PET fibers was significantly improved by N-oxide functionalization. Almost all adsorbed dyes were eluted by acetic acid in methyl alcohol. Ten removal-desorption cycles indicated that the reactive fibers were favorable for use again without the notable change in removal capacity. The information gained from these studies showed that the N-oxide-4-VP-g-PET fibers demonstrated potential as an effective adsorbent for the extremely effective removal of cationic dyes from aqueous media.Öğe Synthesis of modified poly(ethylene terephthalate) fibers with antibacterial properties and their characterization(Taylor & Francis As, 2019) Arslan, Metin; Gunay, KubraPoly(ethylene terephthalate) (PET) fibers were grafted with vinyl monomers by utilizing benzoyl peroxide. Grafted PET fibers were modified in optimized conditions with several functional groups such as amine, chlorine, hydrogen peroxide(,) and triclosan to gain antibacterial feature. The second part of this study comprised examination of the antibacterial features of PET fibers via use of Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922) bacteria. Kirby-Bauer test is used to study antibacterial properties. The longest zone diameter for Trc-GMA-g-PET fibers was 56 mm for E. Coli whereas the biggest diameter for S. aureus bacteria was 130 mm with Trc-MMA-g-PET fibers.Öğe Elimination of carcinogenic bromate ions from aqueous environment with 4-vinyl pyridine-g-poly(ethylene terephthalate) fibers(Springer Heidelberg, 2019) Gunay, Kubra; Arslan, Metin; Bozkaya, Ogun; Aluc, Yasar; Gok, Zehra GunIn this study, poly(ethylene terephthalate) fibers grafted with 4-vinyl pyridine (PET-g-4VP) was synthesized with using a radical polymerization method and its removal capacity for bromate ions in the aqueous solution was explored. The synthesized graft copolymer was structurally characterized by scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR). The effect of some parameters such as pH, grafting rate, processing time, and ion concentration on bromate removal was examined with batch experiments. The sorptions of bromate onto the PET-g-4VP fibers were both verified with FTIR and X-ray fluorescence analysis (XRF) and the remaining amount of bromate after adsorption process was determined with an ion chromatography (Shimadzu). Moreover, kinetic and isotherm studies were also performed for adsorption of bromate with the grafted fibers. The point of zero charge (pH(pzc)) of the PET-g-4VP fibers was found to be 7.5 and the fibers removed maximum amount of bromate from aqueous solution at pH 3. Equilibrium time of adsorption was determined to be 75 min and the adsorption kinetic was found to be pseudo-second-order model. It was observed that the increase in the amount of grafted 4VP onto the PET fibers increased the bromate removal capacity of the fibers; however, when the grafting yield of 4VP was over 80%, the bromate removal ability of the fibers decreased. The maximum bromate removal capacity of the PET-g-4VP was determined to be 183 mg/g when the initial bromate amount was 800 mg/L, treatment time was 75 min, pH of the solution was 3, and 4VP grafting yield was 80%. When the initial bromate concentration was higher than 800 mg/L, the removal rate of the PET-g-4VP fibers was not changed. In addition, bromate ion adsorption data indicated compliance with the Freundlich isotherm. The adsorbent fibers obtained by this study may be promising candidates for the removal of bromate ions from the aqueous media.Öğe Removing of Congo red from aqueous solution by 2-hydroxyethyl methacrylate-g-poly(ethylene terephthalate) fibers(Springer, 2019) Gok, Zehra Gun; Gunay, Kubra; Arslan, Metin; Yigitoglu, MustafaGrafting of 2-hydroxyethyl methacrylate (HEMA) on poly(ethylene terephthalate) (PET) fibers was carried out via free-radical polymerization technique using benzoyl peroxide as initiator. The obtained copolymers were examined by scanning electron microscope and Fourier-transform infrared spectroscopy analysis, and it was proved that HEMA was successfully grafted onto the PET structure. The synthesized fibrous adsorbents were used to remove Congo red (CR) from aqueous solutions by batch adsorption method. The effects of pH, grafting yield, operation time and dye concentration were studied to find optimal conditions for adsorption of CR by the HEMA-grafted PET (PET-g-HEMA). The obtained results showed that the amounts of adsorbed dye on the PET-g-HEMA lowered with increasing pH. At pH 2, the dye amount adsorbed by the fibers increased with increasing dye concentration up to 70 ppm and grafting yield up to 110%. It was also seen that the adsorption had considerably rapid kinetic and achieved equilibrium within 60 min. The maximum removing abilities of the grafted fibers was found to be 16 mg/g when the beginning concentration of CR was 70 ppm at pH 2. The dye was desorbed from the loaded fibers with 1 M NaOH solution, and it was found that 83% of the adsorbed dye was recovered. The investigations on reusability of the PET-g-HEMA fibers showed that the constructed fibers can be used at least five times without losing adsorption capacities for CR. All these results indicate that the grafting can be used to remove the anionic dyes from the aqueous solution.Öğe Synthesis of amine-functionalized methacrylic acid-g-poly(ethylene terephthalate) fiber and its Congo red removal ability(Springer, 2018) Arslan, Metin; Gunay, KubraThe two kinds of amine-type adsorbents were synthesized by reacting hexamethylenediamine (HMDA) and tetraethylenepentamine (TEPA) with methacrylic acid-g-poly(ethylene terephthalate) (MAA-g-PET) fiber for the removal of Congo red (CR) dye from an aqueous solution. The effect of solvents (toluene, ethanol, 2-propanol, and water) on modification of carboxylic acid group of MAA-g-PET fiber to amine groups (HMDA and TEPA) was investigated. Ethanol and 2-propanol provided a higher amination amount of PET fibers for HMDA and TEPA, respectively. The amination amount of PET fibers increased with increasing concentration of amine (vol%) and graft yield. Effect of various parameters such as pH, graft yield, treatment time, and initial dye concentration on the removal amount of CR on chelating fiber was studied. The removal of CR was higher on the TEPA-MAA-g-PET fiber than on HMDA-MAA-g-PET fiber. The effective pH was 3 for adsorption on HMDA-MAA-g-PET fiber and 6 for adsorption on TEPA-MAA-g-PET fiber. The maximum removal capacities of HMDA-MAA-g-PET fiber and TEPA-MAA-g-PET fiber were 11 and 21 mg/g fiber adsorbent for CR. Consequently, the amine-functionalized MAA-g-PET fiber has demonstrated potential as an effective adsorbent for the removal of acidic dyes from aqueous media.Öğe Initial Results of Testing a Multilayer Laser Scanner in a Collision Avoidance System for Light Rail Vehicles(Mdpi, 2018) Luy, Murat; Cam, Ertugrul; Ulamis, Faruk; Uzun, Ibrahim; Akin, Salih IbrahimThis paper presents an application to detect and track obstacles using a multilayer laser scanner. The goal of the detection system is to develop collision avoidance for the Light Rail Vehicle (LRV). The laser scanner, which is mounted in front of the tram, collects information in a four-scan plane. The object recognition and tracking module, which is composed of a three sub-modules segmentation, classification, and Kalman Filter tracking, was carried out on the raw data. Thus, data were provided for collision avoidance module. The proposed system was applied to a tram named "Silkworm" which is manufactured by Durmazlar Machine Inc. (Bursa, Turkey) and initial experimental tests have been conducted at the facilities of Durmazlar Machine Inc. in the city of Bursa, Turkey. This study aims to illustrate parts of the possible tests that can be carried out and to share with the scientific community an important application of multilayer laser scanners, although in the initial implementation phase, in urban rail transportation.Öğe Computational investigations of mechanic, electronic and lattice dynamic properties of yttrium based compounds(World Scientific Publ Co Pte Ltd, 2018) Yildiz, Gokcen Dikici; Yildiz, Yasin Gokturk; Selgin, A. L.; Iyigor, Ahmet; Arikan, NihatElectronic, mechanic and lattice dynamic properties of yttrium-based compounds, X3Y, where X = Pd, Pt and Rh were investigated using the density functional theory. The electronic band calculations demonstrated that X3Y compounds are metallic at the cubic crystal structures. The calculated elastic constants using the energy-strain method indicate that the three materials are mechanically stable. The calculated bulk modulus and Young's modulus values suggest that the Pt3Y is stiffer than that of the other two. The type of bonding and ductility in the X3Y compounds were also evaluated based on their B/G ratios, Cauchy pressures (C-12-C-44) and band structure calculations. These compounds were found to be ductile in nature. The density functional perturbation theory was used to derive full phonon frequencies and total and projected phonon density of states. The computed full phonon spectra for X3Y compounds show that these compounds in the L1(2) phase are dynamically stable. Debye temperature and specific heat of these compounds were also calculated and evaluated using quasi harmonic approximation.Öğe Synthesis and characterization of PET fibers grafted with binary mixture of 2-methylpropenoic acid and acrylonitrile by free radical: its application in removal of cationic dye(Springer, 2017) Arslan, Metin; Gunay, KubraGrafting of binary vinyl monomer mixtures such as 2-methylpropenoic acid (MPA) and acrylonitrile (AN) onto poly (ethylene terephthalate) fibers (PET) was achieved in an aqueous medium with using benzoyl peroxide like free radical initiator. A new reactively fibrous adsorbent was used for removal of dye such as methylene blue (MB) from aqueous media through batch sorption method. Fibers adsorbent was swelled in solution to support the graft and the subsequent polymerization of MPA/AN onto polyester fibers. Optimum conditions for grafting were discovered and reactive fiber were characterized. Variations of graft yield with time, temperature, initiator concentration and monomer mixture ratio were investigated. The optimum initiator concentration was found to be 8 x 10(-3) mol/L. The percentage of grafting rose steadily with the vinyl monomer mixture monomer concentration (50 %). The optimum temperature and polymerization time were found to be 80 A degrees C and 120 min, respectively. The use of AN and MPA monomers together in grafting produce a significant increased in the graft yield. Experimental studies showed that the percentage removal of MB was a great higher on the MPA/AN grafted PET (MPA/AN-g-PET) fibers than on the original PET fibers. The adsorbed quantity of MB improved with pH and basic pH was appropriate for the elimination of MB. MPA/AN-g-PET fibers removed 98 % of cationic dye when initial concentration diverse from 10 to 80 mg L-1 at pH 9.0. Almost all of the adsorbed cationic dye was eluted by ethanoic acid in methanol. Ten removal-desorption cycles indicated that the reactive fibers were favorable for repetitive use without notable change in removal capacity. Consequently, the MPA/AN-g-PET fibers have demonstrated potential as an effective adsorbent for the extremely effective removal of cationic dyes from aqueous media.Öğe Effect of Thermocycling on the Structure of Martensite and Kinetics of Martensitic Transformation in Alloy Fe-30% Ni-3% Pd(Springer, 2017) Yildiz, Yasin Gokturk; Yildiz, Gokcen DikiciThe methods of scanning electron microscopy, differential scanning calorimetry and x-ray diffraction are used to study the morphological and thermal characteristics of cooling-induced martensite in alloy Fe - 30% Ni - 3% Pd. It is shown that the kinetics of the martensitic transformation is athermal and the morphology is lamellar. The mean values of the parameters of the austenite and martensite lattices are 0.35704 and 0.28614 nm respectively. The thermocycling leaves the points A (s) and A (f) invariable.Öğe Position Estimation with Fuzzy Logic Based Dead Reckoning for GPS-Denied Environment(2017) Lüy, Murat; Ulamış, Faruk; Çam, ErtuğrulThe importance of security precautions has been increased as a consequence of raised terrorist incidents. Terrorist acts that move into the city from country sides have made tracking of security and military personnel more important. GPS signals, densely utilized for this tracking, pose a problem in signal blockage situation and GPS-denied environments. The main goal of this research is that to develop a practical positioning system for walking military personnel in GPS denied environments. The system is very useful for GPS signal blockage environments, such as tunnels, thick-walled structures and dense high rise buildings, etc. Proposed system contains a 6-degree of freedom (DOF) inertial measurement unit (IMU) and digital compass attached to the military personnel’s shoe. Tri-axis accelerometer and gyroscope measurements are obtained by IMU. These measurements are applied to fuzzy logic algorithms and total displacement for each step is calculated. Digital compass is utilized to determine direction of personnel. Thus, current location has been estimated with the known starting pointÖğe Local Spin Induced Magnetism In The Monolayer Nanographene(2019) Yıldız, Yasin GöktürkIn this paper, we investigated local spin orientation (up or down) effects on magnetizations of the monolayer nanographene by using effective field theory developed by Kaneyoshi. It is found that the monolayer nanographene and its components have very small magnetization (mC1mC2mC3mMLNG2.31x10-180) at T0.00 for the Jd10 (C1-spin up, C2-spin down and C3-spin up). On the other hand, for Jd20, Jd30, Jd40, and Jd50, the monolayer nanographene and its components (C1, C2 and C3 atoms) have very large local spin induced magnetization (mC1mC2mC3mMLNG1;12.31x10-18) than those of the Jd10. These results clearly indicate that the local spin orientation in the monolayer nanographene has very strong effect on its magnetism.
