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Circular Dichroism Study (circular + dichroism_study)
Selected AbstractsCircular Dichroism Study of the Mechanism of Formation of DNA Templated NanowiresCHEMPHYSCHEM, Issue 15 2008Hamsa Jaganathan Abstract In order to control the fabrication method, the mechanism used in the formation of DNA templated nanowires is investigated through circular dichroism (CD) spectroscopy. Metallic (Au) and magnetic (Fe2O3 and CoFe2O4) nanoparticles (NP) are aligned along the DNA strand at various mass ratios. The DNA templated nanowires are compared to the structure of B-form dsDNA through CD experiments. Absorbance and thermal melting tests are performed to verify the structural changes of DNA templated nanowires. Low concentrations of nanoparticles preserve the DNA B-form through electrostatic interactions. Conversely, at higher concentrations of nanoparticles aligned along the DNA strand, the template is denatured. Information on the mode of nanoparticle binding and DNA helix alterations are explored for metallic and magnetic nanowires based upon the results. [source] Effect of Nonthermal Treatment on the Molecular Properties of Mushroom PolyphenoloxidaseJOURNAL OF FOOD SCIENCE, Issue 5 2003N.K. Sun ABSTRACT To elucidate the mechanism of inactivation of mushroom polyphenoloxidase (PPO) by nonthermal treatment, PPO solutions were irradiated up to 10 kGy or pressurized at 600 MPa and 800 MPa, respectively. PPO activities were significantly affected by , irradiation, and treatment at 5 kGy decreased the activity by 93%. Treatment of PPO at 600 MPa decreased the activity slightly, yet 10 and 20 min treatments at 800 MPa decreased the activities by 28% and 43%, respectively. Circular dichroism study showed that nonthermal treatment altered the ellipticity values in the range of 210 and 225 nm, resulting in decrease of the ordered structure. Fluorescence spectroscopy indicated that nonthermal treatment quenched the emission intensity. [source] Soft X-ray absorption spectroscopy and magnetic circular dichroism study of electroless-deposited CoNiFe ternary alloy soft magnetic filmsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2006Masahito Tanaka Abstract We studied microscopic magnetic properties of each consistent atom in boron added CoNiFe electroless-deposited soft magnetic films, which is a promising candidate for the soft magnetic underlayer of the perpendicular magnetic recording medium, by X-ray absorption spectra (XAS) and magnetic circular dichroism (MCD) measurement. It was found that various monoxides and Fe sesquioxide coexisted with the metals at the upper part of the films. The results of MCD sum rule showed the expected values of orbital angular moment ,Lz, for the film with macroscopic magnetic domain boundaries were larger than those of without domains at Co and Ni atoms and smaller at Fe atom. The appearance of macroscopic magnetic domain boundaries probably originated from the increase in ,Lz, of Co and/or Ni atoms. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Absolute configuration and conformational analysis of a degradation product of inhalation anesthetic Sevoflurane: A vibrational circular dichroism studyCHIRALITY, Issue 8 2002Feng Wang Abstract 1,1,1,3,3-pentafluoro-2-(fluoromethoxy)-3-methoxypropane, compound B, is a product obtained in the degradation of the anesthetic Sevoflurane. Enantiopure (+)- B was investigated using vibrational circular dichroism (VCD). Experimental absorption and VCD spectra of (+)- B in CDCl3 solution in the 2,000,900 cm,1 region are compared with the ab initio predictions of absorption and VCD spectra obtained from density functional theory using B3LYP/6-31G* basis set for different conformers of (S)-1,1,1,3,3-pentafluoro-2-(fluoromethoxy)-3-methoxypropane. This comparison indicates that (+)- B is of the (S)-configuration in CDCl3 solution, in agreement with previous literature results. Our results also indicate that this compound adopts six predominant conformations in CDCl3 solution. Chirality 14:618,624, 2002. © 2002 Wiley-Liss, Inc. [source] | ||||||||||