Chemistry / Kimya
Permanent URI for this collectionhttps://hdl.handle.net/11147/4072
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Conference Object Optimization of Mass Spectrometric Ionisation Efficiency Data(Springer Verlag, 1997) Özgen, İsmet Tamerkan; Altungöz, Oya; Salih, B.; Vandeginste, B. G. M.A new method is developed and tested to find out the excited electronic and vibrational energy levels (fine structure) of molecules from mass spectrometric ionisation efficiency data which were obtained by a conventional mass spectrometer ion source having normal electron energy distribution. Electrons emitted in a conventional mass spectrometer ion source are not monoenergetic, therefore, evaluation of Ionisation Potentials (IF) and Appearance Potentials (AP) from experimental data creates some problems. This is even worse in the evaluation of Fine Structure (excited electronic and vibrational energy levels) from ionisation efficiency data [1]. This is overcome either by using specially designed monoenergetic ion sources which have their own problems (manufacture of special design, difficulty of operation, too much decrease of ion current), or by eliminating disturbing effects in the ionisation efficiency data by some deconvolution techniques [2,4,5,6,7,9]. In this study attempts were made to eliminate the deteriorating effects (mainly arising from electron energy distribution and noise) in the ionisation efficiency data by a deconvolution technique. The technique was applied to the ionisation efficiency data of molecular nitrogen,oxygen and methylammine and its fragment and interesting results were obtained.Conference Object Effect of Some Physical, and Chemical Variables on Flocculation and Sediment Behaviour(A.A. Balkema Publishers, 2000) Polat, Hürriyet; Polat, Mehmet; İpekoğlu, ÜnerEffect of some chemical and physical variables on the settling rate, final sediment height, sediment viscosity and supernatant turbidity of a clay sample was studied using various polyacrylamide type flocculants. Increasing flocculant concentration significantly increased both the settling rate and sediment viscosity. More importantly, changes in the final sediment, height, hence the packing density, was minimal for all the conditions tested once the sediment was allowed to consolidate. Also, the mode of addition of the polymer, at once or continuous, did not seem to affect any of the parameters measured. Conditioning time seemed to alter the settling rate at low polymer concentrations, but had no effect at high polymer concentrations. However, increasing the conditioning time caused a decrease in the sediment viscosity. Different types of the polyacrylimides generated different settling rates at a given concentration, but the final sediment height was nearly independent of polymer type.Conference Object Labeling of Gly-Gly With Technetium-99m and the Assessment of It's Radiopharmaceutical Potential(Springer Verlag, 2001) Taner, M.S.; Özdemir, Durmuş; Köseoğlu, K.; Argon, M.; Dirlik, A.; Duman, Y.[No abstract available]Conference Object Use of Ion Flotation To Remove Copper From Waste Waters(2006) Erdoğan, Demet; Polat, Hürriyet; İpekoğlu, ÜnerFlotation studies were carried out to investigate the removal of copper from wastewaters. Various parameters such as pH, surfactant and frother concentrations and airflow rate were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and Hexadecyltrimethyl ammonium bromide were used as collectors. Recoveries as high as 90% could be to obtained under optimum conditions.Article Citation - WoS: 2Reduction of Carbon Dioxide During the Synthesis of Metal Nano-Particles in Water(Elsevier Ltd., 2003) Polat, Hürriyet; Cohen, H; Meyerstein, D; Rusonik, I.An effort was made to synthesize "carbon-free" metal (Fe-0, Co-0, Ni-0) nano-particles via the reduction of their salts with BH4- in aqueous solutions. Surprisingly it was found that when the synthesis is carried out in the presence of CO2, e.g., in aerated solutions, the CO2 is catalytically reduced by BH(4)(-)on the surface of the metal particles. Carbon-free metals can be prepared by reduction under an inert atmosphere. Thus metal surfaces might have acted as catalysts for CO2 fixation, probably via the initial formation of carbon clusters, in the reductive atmosphere in the prebiotic era. (C) 2003 Elsevier B.V. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 5Mini-Review: "ball-Type Phthalocyanines": Similarities and Differences From Mono Phthalocyanines(Bentham Science Publishers, 2019) Göl, Emre Yusuf; Karabudak, EnginBall-type phthalocyanines are recently synthesized binuclear derivatives of the widely known phthalocyanine molecule. In the ball-type Pc molecule, two cofacially arranged Pc rings have four bridged substituents on the peripheral positions of benzenes. Due to their cofacially arranged phthalocyanine rings and, strong intramolecular and intermolecular interactions, ball-type phthalocyanines have different properties than their parent molecule and these structures have many potential application areas. This review describes three different synthesis methods of ball-type phthalocyanines; synthesis in the solvent, synthesis in solid, and synthesis under microwave irradiation. The synthesis that occurs in the shortest time with the highest yield is the synthesis in the solid phase. General differences between a ball-type phthalocyanine and a monophthalocyanine, such as differences in electronic spectra and effects of cofacial arrangement and central metal atoms, are also discussed. The shape of the Q-bands indicates the differences in electronic spectra. In ball-type Pcs, the Q-bands are broad and have poor resolution. Some potential applications, such as gas sensors, NLO devices, potential usage in photodynamic therapy and artificial photosynthesis of ball-type phthalocyanines are also mentioned. Ball-type Pcs can be used as a sensor for gases such as; CO2, CO, SO2, VOC. A novel water-soluble ball-type Pc may have potential application in PDT. Finally, we consider future prospects of these molecules.Conference Object Semi-Synthetic Studies on Astragaloside Vii and Immunomodulatory Activities of the Derivatives(Georg Thieme Verlag, 2019) Yakuboğulları, Nilgün; Sağ, Duygu; Çağır, Ali; Bedir, ErdalAdjuvants have been used in vaccine sector since 1920s to increase the immunogenicity of antigens, reduce the dosage and minimize frequency of immunizations [1]. The use of saponins as adjuvant in the prophylactic/therapeutic human and veterinary vaccines, and investigation of their immunomodulatory activities have gained importance in recent years [2],[3]. Astragaloside VII (AST VII), a triterpenoid saponin isolated from Astragalus species, stimulates Th1 mediated immune response, antigen-specific antibody response and splenocyte proliferation.Article Citation - WoS: 3Citation - Scopus: 4Evaluation of Multifunctional Hybrid Analogs for Stilbenes, Chalcones and Flavanones(Bentham Science Publishers, 2017) Çağır, Ali; Odacı, Burcu; Varol, Mehmet; Akçok, İsmail; Okur, Özgür; Koparal, Ayşe T.Aims: In this study, discovery of novel anticancer agents acting by more than one mechanism was aimed. Method: For this purpose, eleven previously synthesized simple-stilbene, chalcone, flavanone derivatives and 31 novel stilbene-fused chalcones and stilbene-fused flavanones were tested for their aromatase inhibition, anti-angiogenic and anti-proliferative properties in cancer (PC3, MCF-7) and healthy (HUVEC) cell lines. MTT cell viability assay was used to evaluate the anti-proliferative activities of the compounds. CYP19/MFC high-throughput screening kit (BD Biosciences, Oxford, UK) was used to search the aromatase inhibition properties and matrigel tube formation assay was applied to determine the anti-angiogenic activities. Results: Results indicate that the simple-chalcone and flavanone derivatives were more cytotoxic than the simple-stilbenes in the both cancer cell lines. In contrast, the simple-stilbene structures were much more effective at aromatase inhibition. The cytotoxicity profiles of stilbene-fused chalcones in cancer cells imply that these molecules mostly mimic the simple chalcone structures. On the other hand, flavanones lose their cytotoxic activities after becoming fused with stilbenes. Additionally, aromatase inhibition assays showed that stilbene-fused chalcones again do mimic the simple-chalcones but not simple-stilbenes and anti-angiogenic profiles of the tested molecules seem to be not related with stilbene fragments. Furthermore, stilbene-fused flavanones may mimic both simple-flavanones and simple-stilbenes depending upon the type and position of the substituent in their respective terminal aromatic rings.Article Citation - WoS: 21Citation - Scopus: 24Modification of Electrospun Pva/Paa Scaffolds by Cold Atmospheric Plasma: Alignment, Antibacterial Activity, and Biocompatibility(Springer Verlag, 2019) Arik, Nehir; İnan, Alper; İbiş, Fatma; Demirci, Emine A.; Karaman, Ozan; Ercan, Utku K.; Horzum, NesrinThe ongoing search for better antibacterial wound care dressings has led to the design and fabrication of advanced functional nanomaterials. Taking advantage of electrospinning and cold atmospheric plasma (CAP), free-standing nanofibrous scaffolds are promising for use in novel biomedical applications. Random and aligned polyvinyl alcohol (PVA)/polyacrylic acid (PAA) nanofiber scaffolds are fabricated by electrospinning and treated with CAP. In this study, we investigate the effects of CAP treatment on alignment, hydrophilicity, antibacterial activity, and biocompatibility in determining the surface properties of the nanofibrous scaffolds. The results of vibrational polarization spectroscopy analysis indicate that CAP treatment changes the degree of alignment of the nanofibers. Furthermore, both random and aligned CAP-treated nanofibrous scaffolds show significant antibacterial activity against the E. coli strain. The results of an in vitro scratch assay reveal that CAP treatment of PVA/PAA nanofibers has no toxic effect.Article Citation - WoS: 6Citation - Scopus: 6Esterification of 1-Octanol on Clinoptilolite-Supported Tio2 Catalysts(Springer Verlag, 2019) Özyağcı, Bensu; Şahin, Volkan; Karabakan, AbdulkerimIn this study, a natural type of zeolite, Clinoptilolite (CLI), is used as a support for TiO2. First, TiO2-supported heterogeneous catalysts originated from the high temperature calcination of TiCl4 groups, which were thermally immobilized on clinoptilolite, were obtained. Powder-XRD and EDX analyzes showed that the oxide form of Ti-immobilized on dealuminated clinoptilolite were formed in the anatase phase, and the zeolite structure was preserved. As seen in TGA/DTA analyzes, this catalyst could be efficient and have high stability for many reactions. Second, the esterification reaction of 1-octanol with acetic acid is used as a reference reaction for this catalyst.