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Publication Metadata only Molecular Mechanics Studies of Antihypertensive Val-Tyr Dipeptide(Asian Journal Of Chemistry, 11/100 Rajendra Nagar, Sector 3,, Sahibabad 201 005, Ghaziabad, India, 2010-01) Akverdieva, G. A.; Godjayev, N. M.; Doğan, N. E.; AKYÜZ, ZEKİ TANIL; AKYÜZ, SEVİM; TR10127; TR111424The spatial structure of anti hypertensive dipeptide,Valine-Tyrosine was investigated within molecular mechanics framework. It ha, been shown that the molecule has such a structural organization which does not exclude the realization of two types of conformation: folded and extended. The energy and geometrical parameters for the optimal conformations of dipeptide are obtained. The electronic characteristics for these structures were analyzed by quantum chemical calculations.Publication Metadata only Bifurcations of Fibonacci generating functions(PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND, 2007-08) Özer, Mehmet; Cenys, Antanas; Hacıbekiroğlu, Gürsel; Akat, Ercüment; Valaristos, A.; Anagnostopoulos, A. N.; POLATOĞLU, YAŞAR; TR2509; TR199370In this work the dynamic behaviour of the one-dimensional family of maps F-p,F-q(x) = 1/(1 - px - qx(2)) is examined, for specific values of the control parameters p and q. Lyapunov exponents and bifurcation diagrams are numerically calculated. Consequently, a transition from periodic to chaotic regions is observed at values of p and q, where the related maps correspond to Fibonacci generating functions associated with the golden-, the silver- and the bronze mean. (c) 2006 Elsevier Ltd. All rights reserved.Publication Metadata only Structural and spectroscopic investigation on antioxidant dipeptide, L-Methionyl-L-Serine: A combined experimental and DFT study(Elsevier Science Bv, Po Box 211, 1000 AE Amsterdam, Netherlands, 2017-06-05) Kecel Gündüz, Serda; Bıçak, Bilge; Çelik, Sefa; Özel, Ayşen E.; AKYÜZ, SEVİM; 110526; 277135; 110147; 10127; 110745The focus of this study is to determine the conformational, structural and vibrational properties of Methionyl-Serine dipeptide (L-Methionyl-L-Serine, Met-Ser), a biological active molecule. To investigate their energetically preferred conformations, molecular mechanics methods were utilized to determine the optimal conformations of the 3402 different dihedral angle values of the backbone and side chains. It was found that the extended (e) backbone shape in the LB conformational range was the most stable LMethionyl-L-Serine dipeptide conformation, with 3.12 kcal/mol of energy. Density Functional Theory (DFT) was used to determine the optimized geometry, the vibrational wavenumbers and modes of the title dipeptide values, with 6-31G (d,p) and 6-311++G (d,p) basis sets. The potential energy distribution data was used to carry out the assignment of the bands. In addition, the vibrational spectra of the most stable conformer and its dimer form were determined and the obtained results were compared with the experimental IR and Raman spectra in the solid phase. To determine the presence of intramolecular charge transfer, molecular dipole moment, polarizability and hyperpolarizability, the Natural Bond Orbital (NBO), HOMO LUMO calculations, the linear polarizability (alpha) and the first order hyperpolarizability (fio) value analyses of the investigated molecule were carried out using the DFT with the B3LYP/6-31++G(d,p) basis set. This study aims to determine a relatively stable conformation of antioxidant dipeptide and to investigate the molecular geometry, molecular vibrations and hydrogen bonding interactions between monomeric and dimeric forms of Methiony-Serine dipeptide. (C) 2017 Elsevier B.V. All rights reserved.Publication Metadata only On lambda-fractional convex functions(2007) Owa, Shigeyoshi; YAVUZ, EMEL; POLATOĞLU, YAŞAR; 199370; 111202Publication Metadata only Structure and Vibrational Spectra of Benzidine(Elsevier, 2003-06-01) Akalın, Elif; AKYÜZ, SEVİM; 46357; 10127The geometry and vibrational spectrum of benzidine have been computed by ab initio calculations using the DFT/B3LYP method with 6-31+G(d,p) basis set. In the most stable geometry, the dihedral angle between the two phenyl rings was found to be around 38°. Calculated wavenumbers were scaled by a single factor 0.965 to approximately correct for vibrational anharmonicity as well as for overestimation of the force constants. Normal coordinate analysis of benzidine and some of its deuterated derivatives have also been performed in valance force field approximation in order to demonstrate the transferability of the force field of aniline. Good agreements between the two different calculation results (ab initio and force field refinement methods) and between the calculated and observed values are found.Publication Metadata only Spectroscopy and Chemometrics as Central Prospective Tools to Investigate Biologically Relevant Materials(2018) ILDIZ, GÜLCE ÖĞRÜÇ; 107326Publication Metadata only Radioisotope Excited X Ray Fluorescence Analysis of Ashes From Coal Power Plants of Turkey(Kluwer Academic Publishers, 1998-01) Başsarı, A.; AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL; 10127Fifteen ash samples taken from filters and bottom products of boilers or chimneys of seven coal fired power plants in Turkey have been analysed quantitatively for some minor elements using radioisotope energy dispersive X-ray fluorescence (EDXRF). It is found that samples contain Cu, Zn, Rb, Sr, Zr, Mo, Cs, Sb, Ba, Pb, Y, La, Ce, Nd and Sm in different amounts. An ash sample taken from the electro-filter of the Ambarli, fuel oil fired-power plant was also analysed for comparison and found that it contained the smallest amount of potentially toxic elements.Publication Metadata only Conformational Analysis And Vibrational Spectroscopic Studies On Dapsone(Maik Nauka/Interperiodica/Springer, 233 Spring St, New York, Ny 10013-1578 Usa, 2012-11) AKYÜZ, SEVİM; ILDIZ, GÜLCE ÖĞRÜÇ; TR107326; TR10127In this study, the theoretical conformation analysis of free dapsone has been performed by single point energy calculations at both semi-empirical PM3 and DFT/B3LYP-3-21G theory levels and three stable conformers were determined. Both the IR and Raman spectra of the molecule in solid phase have been recorded. The IR intensities and harmonic vibrational wavenumbers of each conformer were calculated by DFT method at B3LYP/6-31++G(d,p) theory level. For the fundamental characterization, the total energy distribution (TED) calculations of the vibrational modes were done using parallel quantum mechanic solution program (SQM) and the fundamental modes were assigned. The theoretical results are in agreement with the experimental ones.Publication Metadata only Ft-Ir And Edxrf Analysis Of Wall Paintings Of Ancient Ainos Hagia Sophia Church(Elsevier Science Bv, Po Box 211, 1000 Ae Amsterdam, Netherlands, 2009-04-30) Başaran, Sait; Kocabaş, I.; Güleç, A.; Çeşmeli, H.; Uçar, B.; AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL; TR10127; TR111424The wall paintings of ancient Ainos Hagia (Saint) Sophia Church were investigated by FT-IR and EDXRF spectroscopy. Calcite, aragonite, gypsum, and quartz were detected in all the samples. Feldspar phases and pigments were inferred from both band component analysis and the second derivative profiles of the IR spectra. The black, dark brown, and red colouration was due to different concentrations of MnO2, Mn2O3, magnetite, and haematite. (C) 2009 Elsevier B.V. All rights reserved.Publication Metadata only A possible link between kHz quasi-periodic oscillations and the magnetospheric boundary(E D P Sciences, 17 Ave Du Hoggar Parc D Activites Coutaboeuf Bp 112, F-91944 Cedex A, France, 2014) Erkut, Mehmet HakanThe quasi-periodic oscillations (QPOs) observed with a 200-1300 Hz frequency range in the X-ray power spectra of low mass X-ray binaries (LMXBs) might be considered as one of the observational clues to the physics at the innermost regions of accretion disks around neutron stars. In a neutron star LMXB, the magnetospheric boundary is likely to be close to the surface of the neutron star because of its presumably weak magnetic dipole field. The kHz QPOs can therefore be interpreted as the modulation of X-ray emission with smallest timescales associated with the dynamics of accreting disk matter at the magnetospheric boundary. As a result of magnetosphere-disk interaction we expect the rotational dynamics of the disk matter in the boundary region to be characterized by either sub-Keplerian or super-Keplerian flow depending on the fastness of the neutron star. We summarize our current understanding of the kHz QPO frequency correlations in terms of the oscillatory modes amplified in the magnetic boundary region and discuss the future prospects related to the possible link between kHz QPOs and the rotational dynamics at the magnetospheric boundary.