Yazar "Zengin, B." seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    High-field NMR T 2 relaxation mechanism in D2O solutions of albumin
    (Springer, 2013) Yilmaz, A.; Zengin, B.
    400 MHz NMR T (2) in D2O solutions of albumin and pure D2O were measured at different temperatures. A relation, based on the chemical exchange between bound HDO and non-exchangeable protein protons, was derived theoretically for the contributions of bound HDO [P (b)(1/T (2b))]. A second relation was also derived theoretically by considering spin-rotation interactions between bound HDO and surrounding protein protons. The P (b)(1/T (2b)) values in albumin solutions were then determined by replacing experimental data into the first relation. The values of the 1/T (2) and P (b)(1/T (2b)) in albumin solutions increase linearly with temperature(T), whereas the 1/T (2) in D2O decreases with T. In addition, the spin-rotation correlation times were calculated from the second relation. The dipolar correlation time of albumin was then reproduced from the spin-rotation correlation times for confirmative purposes. In conclusion, the 1/T (2) in albumin solutions with D2O is caused by spin-rotation interactions.
  • [ X ]
    Öğe
    Investigation of energy relaxation in 1-D nonlinear lattices by wavelets
    (Springer, 2012) Zengin, B.; Yaraneri, H.; Korunur, S.
    The movement and relaxation of the localized energy on FPU lattices have been studied by using Wavelet transforms methods. The energy relaxation mechanism for nonlinear chains involves the degradation of higher frequency excitations into lower frequencies. It is shown that low frequency modes decay more slowly in nonlinear chains. The wavelet spectrum exhibits a behavior involving the interplay of phonon modes and breather modes.
  • [ X ]
    Öğe
    NMR Proton Spin-Lattice Relaxation Mechanism in D2O Solutions of Albumin Determined at 400 MHz
    (Springer, 2014) Yilmaz, A.; Zengin, B.; Ulak, F. Sadan
    T-1 values in pure D2O and D2O solutions of human serum albumin (HSA) were measured versus temperature. A formula was derived based on H-H interactions between the surface HDO and non-exchangeable protein protons. The formula was used to evaluate the average distance of the interactions (rav). The effective correlation times were then derived by replacing the experimental data in the formula. Short correlation times obtained for the solution with low HSA (0.02 g albumin for one ml of D2O) decreased from 53 to 29 ps, while longer times increased from 1.19 to 2.22 ns. They are of the order of a fraction of a nanosecond for the solution with high HSA (0.08 g albumin per one ml of D2O). The perfect consistency between the derived theory and experimental data indicates that the high-field 1/T-1 in D2O solutions of albumin is caused by dipolar interactions between the surface HDO and non-exchangeable protein protons. It also suggests that the effective correlation time of the surface HDO is of the order of the mean lifetime of short-lived surface water.