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    Elimination of Radiation Damping Effects from the NMR Relaxation Curves of H2O/D2O Mixtures Containing Protein and Ions
    (Physical Soc Republic China, 2013) Zengin, Bilgin; Koylu, Mehmet Zafer; Korunur, Sibel; Yilmaz, Ali
    In this work the T-1 and T-2 curves of H2O/D2O mixtures were obtained for several fractions of H2O and also for different amounts of albumin and manganese. The experiments were carried out with a 400 MHz proton NMR spectrometer. The T-1 and the T-2 curves were determined by the inversion recovery (IR) and Carr-Purcell-Meiboom-Gill (CPMG) sequences, respectively. The relaxation times in residual water and in a mixture with 0.05 ml H2O were found to be reliable either in the presence or in the absence of albumin. The mixtures containing 0.1 ml or higher H2O suffer from radiation damping (RD). RD was removed gradually by addition of albumin or manganese. RD in the protein solution with 0.1 ml H2O was removed by adding 1 mu g of manganese to one ml of solution. The data suggest that the relaxation times in H2O/D2O mixtures are measurable by conventional methods upon the addition of appropriate amounts of manganese and albumin.
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    Öğe
    The Examination of a Variety of Different Ions Added to the Crown Ether Derivatives with High Field NMR Spectrometer
    (Maik Nauka/Interperiodica/Springer, 2017) Askin, Muzaffer; Zengin, Bilgin; Korunur, Sibel; Kor, Harun; Koylu, M. Zafer
    The current study involves the measurements of T-1 relaxation time of complexes three different crown ethers (4-aminobenzo-15-Crown-5, 1-Aza-18-Crown-6, 1-Aza-15-Crown-5) and two different ions sodium perchlorate (NaClO4), lithium perchlorate (LiClO4) by a 400 MHz NMR spectrometer. The association constants (K-a) of the complexes were determined on the basis of the evaluation of these measurements using the Benesi-Hildebrand method that we have modified. These association constants were consistent with those obtained from H-1 NMR titration technique. As a result, it can be speculated that binding constants could be measured using T-1 relaxation time when chemical shifts are very small or cannot be observed.
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    Öğe
    Interaction of Water and Fiber Free and Fiber Reinforced Acrylic Resins: Studied by 400 MHz NMR
    (Asian Journal Of Chemistry, 2011) Polat, Zelal Seyfioglu; Tacir, Ibrahim Halil; Yilmaz, Berivan Dundar; Korunur, Sibel
    There is no report is available on the interaction of polymerized acrylic resin materials with water studied by high resolution NMR. In this study, the chemical shifts of NMR peaks of water interacting with different types of polymerized acrylic resin materials were compared. Two different types of polymers obtained by heat and microwave, were selected. Each NMR sample was prepared by mixing the dusty materials and 1 mL of a mixture of H2O (80 To) and D2O (20 %). The water proton signals in samples were measured by 400 MHz NMR. The data was divided into four groups. The chemical shifts of microwave acrylic resin (group 3) was higher than that of microwave acrylic resin reinforced with glass fibers (group 4), while the chemical shift of heat cured acrylic resin (group 1) was higher than that of heat cured acrylic resin reinforced with glass fibers (group 2). Furthermore, the chemical shifts of material polymerized by microwave are higher than those polymerized by injection (group 3 > group 1, and group 4 > group 2). Data shows that different type of polymerized acrylic resin materials can be differentiated by chemical shift measurements.
  • Küçük Resim
    Öğe
    Kanser ilaçlarının proteinler ve membranlarla etkileşmelerinin NMR yoluyla incelenmesi
    (2015) Korunur, Sibel
    Bir ilacın soğurulması, dağıtımı, metabolizması ve vücuttan atılmasıyla ilgili bilgilere ulaşma; o ilacın tedavideki başarı etkinliğini anlamak için çok önemlidir. İlaçların dağıtımını etkileyen en önemli faktör, o ilacın insan kan serumundaki albüminine bağlanma çekiciliğidir. İnsan serumunun en bol proteini albümindir. Birçok ligand bağlama yeteneği olan albümin, çeşitli ilaçları da kendisine bağlamaktadır. İlacın hedef organa ulaşabilmesi ve etkili bir tedavi sağlanması için, ilaç ile albümin arasındaki etkileşme optimum olmalıdır. Bu tez çalışmasında, D2O ortamında çözünmüş üç farklı ilaç etken maddesine (5-Fluorouracil (5-FU), Cytosine ß-D Arabinofuranoside (Ara-C), Cyclophosphamide-Monohydrate (CM)) farklı konsantrasyonlarda insan serum albümini eklenerek elde edilen örnekler 400 MHz NMR spektroskopisi ile incelenmiştir. Bu incelemelerde spektrumlar (pikler), kimyasal kaymalar ve piklerin durulma zamanlarına (T1 ve T2) ait veriler kullanılmıştır. Bu verilerden elde edilen sonuçlarla protein-ilaç etkileşmelerinin moleküler dinamiği üzerine bilgi edinilmiştir. Bu tez çalışmasında ayrıca; ilaç etken maddeleriyle iki tip membrane (normal ve diyabetli) etkileştirilmiş ve bu etkileşme sonrası artan ilaç konsantrasyonlarında membrane piklerinin şiddeti ve kimyasal kayma değerleri incelenmiştir. Anahtar Kelimeler: NMR Spektroskopi, ilaç-albumin etkileşmesi, T1 ve T2 durulma zamanı, insan serum albümin, membrane, kimyasal kayma
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    Öğe
    Observation of Triplet Traces Obtained with Inversion Recovery Method in Both Residual Water- and H2O/D2O-Albumin Mixture by Using 400 MHz Proton NMR
    (Asian Journal Of Chemistry, 2013) Yilmaz, Ali; Zengin, Bilgin; Korunur, Sibel
    NMR studies involving H2O/D2O mixtures are mainly based on a single spectrum of water. However, some recent papers have revealed the presence of an HDO triplet in H2O/D2O, which is caused by the splittings of H2O signal by deuterium (D). Observation of inversion recovery (IR) traces of this triplet should be very useful for analyzing relaxation data in such mixtures. In this work, in order to obtain the traces, inversion recovery signal intensities of residual water and a mixture of 0.10 H2O and 0.90 D2O were acquired versus a set of short delay times in the presence or absense of 0.2 g albumin. T-1 and T-2 curves of the same samples were also obtained by using different sets of much longer times for checking the effect of radiation damping on the traces. Experiments were carried out with a 400 MHz proton NMR spectrometer equipped with a topspin programme for relaxation measurements. Inversion recovery data of the traces and T-1 curves were obtained with the inversion recovery method, while T-2 curves were obtained with the Carr-Purcell-Meiboom-Gill method. Data was processed through an analysis programme of the topspin. Data showed that radiation damping is effectively reduced upon addition of albumin. Furthermore, the data of the residual water- and the mixture with albumin demonstrated the traces of the triplet at the initial part of a single inversion recovery line. Our results suggest that the splitting of water proton signal by deuterium can be detectable by the inversion recovery method for D2O- and the mixture containing albumin.