Person: KAHRAMAN, MEMET VEZİR
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KAHRAMAN
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MEMET VEZİR
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Publication Open Access Fluorimetric reusable polymeric sensor for hydrogen sulfide detection(2023-02-01) ÇUBUK, SONER; KAHRAMAN, MEMET VEZİR; Ünaldı A. Ş., Çubuk S., Çiğil A. B., Kahraman M. V.In this study, with the help of reactive monomers, crosslinkers, and photoinitiator that detect H2S in various matrices, an H2S sensitive fluorescence sensor polymerizes under ultraviolet (UV) light was developed. To this goal, a polymeric membrane was prepared, and the characterization of the membrane was carried out with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) methods. Afterward, appropriate conditions were identified, the excitation wavelength was determined as 370 nm, and the emission wavelength was determined as 425 nm. It was established that the fluorescence intensity of the prepared polymeric membrane decreased in the presence of H2S. A detailed analysis was executed to determine the sensor's most suitable pH value and time. It was found that the optimum pH was 8.0, and the optimal duration was 15 s. It has been calculated that the linear range of the developed method is 2.19× 10–8– 6.25× 10–7 M, and the detection limit (LOD) is 7.37× 10–9 M. The effect of some possible interfering ions was investigated, and it determined that the sensor had excellent selectivity. In addition, the sensor used to determine H2S can be used at least 100 times. The recovery percentages were 102.1%–103.2%, and 104.6%, using tap water samples. In terms of providing reliable, fast results, high sensitivity, reusable, low cost, and ease of use, the developed fluorimetric sensor, compared to standard methods, has become more advantageous.Publication Metadata only In vitro ortamda çimlendirilen pamuk (gossypium hirsutum l.) bitkisinde fenolik madde değişimlerinin incelenmesi(2003-09-08) KAHRAMAN, MEMET VEZİR; ÖZYİĞİT, İBRAHİM İLKER; Özyiğit İ. İ. , Ercan Ö., Kahraman M. V.Publication Open Access Molecularly imprinted nanoparticles with recognition properties towards diphtheria toxin for ELISA applications(2022-11-01) KAHRAMAN, MEMET VEZİR; Alkanlı S. S. , Dal Yöntem F., Yaşar M., Güven C., Kahraman M. V. , Kayaman Apohan N., Aktaş Z., Öncül M. O. , Ünlü A., Akçakaya H.Plastic antibodies can be used for in vitro neutralization of biomacromolecules with different fragments due to their potential in separation, purification, chemical sensor, catalysis and drug production studies. These polymer nanoparticles with binding affinity and selectivity comparable to natural antibodies were prepared using functional monomer synthesis and copolymerization of acrylic monomers via miniemulsion polymerization. As a result, the in vitro cytotoxic effect from diphtheria toxin was reduced by MIPs. In vitro imaging experiments of polymer nanoparticles (plastic antibodies) were performed to examine the interaction of diphtheria toxin with actin filaments, and MIPs inhibited diphtheria toxin damage on actin filaments. The enzyme-linked immunosorbent assay (ELISA) was performed with plastic antibodies labeled with biotin, and it was determined that plastic antibodies could also be used for diagnostic purposes. We report that molecularly imprinted polymers (MIPs), which are biocompatible polymer nanoparticles, can capture and reduce the effect of diphtheria toxic and its fragment A. HIGHLIGHTS Macromolecules can be imprinted by using their fragments as template molecules. MIPs gain an affinity for the template molecule by covalent binding, non-covalent interactions or ligand interactions, as well as the ability to bind, release and recognize the template molecule.Publication Metadata only Photo-crosslinked lignin/PAN electrospun separator for safe lithium-ion batteries(2022-10-01) KAHRAMAN, MEMET VEZİR; Kahraman M. V.A novel crosslinked electrospun nanofbrous membrane with maleated lignin (ML) and poly(acrylonitrile) (PAN) is presented as a separator for lithium-ion batteries (LIBs). Alkali lignin was treated with an esterifcation agent of maleic anhydride, resulting in a substantial hydroxyl group conversion to enhance the reactivity and mechanical properties of the fnal nanofber membranes. The maleated lignin (ML) was subsequently mixed with UV-curable formulations (up to 30% wt) containing polyethylene glycol diacrylate (PEGDA), hydrolyzed 3-(Trimethoxysilyl)propyl methacrylate (HMEMO) as crosslinkers, and poly(acrylonitrile) (PAN) as a precursor polymer. UV-electrospinning was used to fabricate PAN/ML/HMEMO/PEGDA (PMHP) crosslinked membranes. PMHP membranes made of electrospun nanofbers feature a three-dimensional (3D) porous structure with interconnected voids between the fbers. The mechanical strength of PMHP membranes with a thickness of 25 µm was enhanced by the variation of the cross-linkable formulations. The cell assembled with PMHP2 membrane (20 wt% of ML) showed the maximum ionic conductivity value of 2.79*10−3 S cm−1, which is signifcantly higher than that of the same cell with the liquid electrolyte and commercial Celgard 2400 (6.5*10−4 S cm−1). The enhanced LIB efciency with PMHP2 membrane can be attributed to its high porosity, which allows better electrolyte uptake and demonstrates higher ionic conductivity. As a result, the cell assembled with LiFePO4 cathode, Li metal anode, and PMHP2 membrane had a high initial discharge specifc capacity of 147 mAh g−1 at 0.1 C and exhibited outstanding rate performance. Also, it efectively limits the formation of Li dendrites over 1000 h. PMHP separators have improved chemical and physical properties, including porosity, thermal, mechanical, and electrochemical characteristics, compared with the commercial ones.Publication Open Access Facile application of terahertz spectroscopy in UV-coated and phase change material loaded MPS(2023-05-01) KAHRAMAN, MEMET VEZİR; Aytan E., Aytekin Y. S., Aytan T. A., Esenturk O., Kahraman M. V.In this study, capability of Terahertz (THz) spectroscopy for determination of thermal properties of phase change materials (PCM) in an acrylated polyurethane coating investigated. Spherical shaped mesoporous silica materials (MPSs) are prepared as a template for stearic acid (SA). SA was impregnated into MPSs for investigate its PCM properties. Surface of MPSs was modifed with 3-(Trimethoxysilyl)propyl methacrylate (MEMO) to add acrylate functionality to form covalently bond to polyurethane (PU)-based composite UV matrix to avert leakage problem. Finally, this resin was photopolymerized and its change in thermal properties was determined by both conventional Diferential Scanning Calorimetry (DSC) and THz. DSC results show that the heating process phase change enthalpy is measured between 20.83 J/g and 136.80 J/g, and the freezing process phase change enthalpy is found between 13.55 J/g and 181.13 J/g by DSC. The thermal properties of phase changing behavior of the sample were also analyzed by Terahertz Time Domain Spectroscopy (THz-TDS). Besides the phase changes THz spectroscopy has shown the temperature dependent variation in the host matrix, also fnal PCM sample. Comparison of the data suggest that THz Spectroscopy is a fairly strong technique for characterization of phase changing materials even in very complex resin environment and it is a strong complementary technique especially following the temperature dependent properties close to room temperature.Publication Metadata only Lityum-iyon piller için poliüretan esaslı esnek jel polimer elektrolit(2022-10-12) UYUMAZ, FATMANUR; KAHRAMAN, MEMET VEZİR; Uyumaz F., Kahraman M. V., Kalybekkyzy S.Lityum-iyon piller, yüksek enerji yoğunluğu, yüksek verimlilik, hafiflik, taşınabilirlik ve güvenlik gibi avantajlı özellikleri sayesinde on yıllardır tüketici elektroniği pazarına bir güç kaynağı olarak hakim olmuştur. Lityum-iyon pillerin sıvı elektrolitlerle uygulanmasında, yüksek derecede yanıcı organik sıvı elektrolitlerin varlığından dolayı sızıntı, alev ve patlama gibi bazı ciddi sorunların meydana geldiği bildirilmiştir. Solvent içermeyen katı elektrolitlerin kullanılması, sıvı elektrolitlerin mevcut güvenlik sorununu çözmenin ideal yoludur, ancak bu avantaj, önemli ölçüde azaltılmış iletkenlik ile birlikte gelir. Sıvı ve katı polimer elektrolitlerin pozitif özelliklerini birleştirmek için sırasıyla daha yüksek iyonik iletkenliğe ve daha fazla kararlılığa sahip jel polimer elektrolitler geliştirilmiştir. Poliüretan akrilat (PUA) bazlı polimer elektrolitlerin sahip oldukları özellikler nedeniyle elektrokimyasal enerji depolama uygulamalarında kullanımları araştırılmıştır. yüksek iyonik iletkenlik, mükemmel mekanik dayanım ve kolay kontrol edilebilir fiziksel özellikler ve yüksek kürlenme hızı. Alifatik Poliüretan akrilat ve poliüretan metakrilat esaslı filmler Pentaeritritol tetrakis (3 merkaptopropiyonat) ve 3-merkaptopropil trimetoksisilan gibi iyonik monomerler kullanılarak fotobaşlatıcı ve tiyol-en kullanılarak soljel yöntemiyle hazırlandı. Bükülebilir esnek polimer elektrolitlerin hazırlanma aşaması UV kürleme teknolojisi ile gerçekleştirilmiştir. Jel film hazırlamada bir yöntem olarak kullanılan UV kürleme teknolojisi, yüksek verim, ışıkla sertleşme koşulları, düşük sermaye harcaması, düşük enerji tüketimi gibi çeşitli avantajları nedeniyle büyük ilgi görmüştür.