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Yoshiaki Hamada

Publications and source records attributed to Yoshiaki Hamada.

6 recordsLinked to original sources
PubMed2007

Fliplike motion in the thalidomide dimer: Conformational analysis of (R)-thalidomide using vibrational circular dichroism spectroscopy.

The dynamic fliplike motion in the (R)-thalidomide dimer has been reported for the first time. The vibrational circular dichroism (VCD) spectrum of (R)-thalidomide in DMSO-d6 indicates the characteristic nu(CO) bands with opposite signs and reflects the structural property of the equatorial configuration of the phthalimide ring. On the other hand, the VCD spectrum of (R)-thalidomide in CDCl3 exhibits a different pattern of nu(CO) bands and suggests the fliplike motion in dimer forms. This novel insight for the dimer forms would be helpful for the understanding of the structure-activity relationship for thalidomide.

Circular Dichroism↗
PubMed2006

Analysis of vibrational circular dichroism spectra of (s)-(+)-2-butanol by rotational strengths expressed in local symmetry coordinates.

The vibrational circular dichroism (VCD) spectra of (S)-(+)-2-butanol have been observed in dilute CS(2) solutions. Two strong VCD bands are assigned mainly to the OH bending modes with the aid of quantum chemical calculations. The calculated VCD spectra corresponding to these bands are shown to depend on the conformation of the OH group. To understand this feature, we have calculated the contribution of each local vibrational mode to the rotational strengths and concluded that the coupling of the group vibrations between the in-plane and out-of-plane modes about the locally assumed symmetry planes play a significant role in VCD. This finding has provided a new scope of VCD in relation to molecular vibrations.

Algorithms↗
PubMed2005

Long-term outcome of patients with rheumatoid arthritis treated by multiple arthroplasty.

We conducted a study of 82 patients with rheumatoid arthritis (RA) who had undergone multiple arthroplasty and investigated their clinical findings and clinical courses. We reviewed the significance of multiple arthroplasty in the treatment of RA, its problems, and measures to solve them. All patients initially regained and maintained good walking capacity. However, the walking capacity of many patients again decreased over the long term; in the tenth year, 79% of patients were capable of a practical gait. The causes of decreased walking capacity included complications of artificial joints, cervical lesions, and vertebral compression fractures. Fractures were observed in as many as nine patients, indicating that it is important to prevent and treat their cause, that is, osteoporosis. The survival rate was 71% in 10 years. In RA patients, particularly those who have undergone multiple arthroplasty, the major causes of death are infection and rheumatic disease, suggesting that prevention of such diseases should be considered paramount. Appropriate systemic treatment of RA, patient education, and measures against osteoporosis for prevention of complications may preserve the worth of multiple arthroplasty for RA patients with multiple joint destruction.

Journal Article↗
PubMed2001

High Resolution FTIR Study on NH(2)Cl Molecule: Inversion and Anharmonicity.

The high-resolution FTIR absorption spectra of the NH(2)Cl molecule have been measured in the region 500-3600 cm(-1). The rotational structures of all the fundamental bands and a number of overtone and combination bands have been analyzed. Every rotational line of the observed bands except the NH(2) twisting and stretching fundamental bands splits into two components due to the amino inversion motion. The vibrational anharmonicity and the direction of the transition moments have been studied with the help of B3LYP/6-31++G(**) calculations. The amount of inversion splitting depends on the molecular rotation, and the J,K-dependence of the inversion splitting has been determined. Copyright 2001 Academic Press.

Journal Article↗
PubMedDate not supplied

Vibrational circular dichroism spectrum of 1-amino-2-propanol.

Vibrational circular dichroism (VCD) spectra of 1-amino-2-propanol, of neat sample and in dilute solution of CDCl3, were measured in 2000 to 800 cm(-1) region. Two VCD bands, which appear at 1272 and 1412 cm(-1) in dilute solution, were assigned, respectively, to the OH bending mode and the mode that is influenced by the OH bending of the most stable conformer. The assignments were confirmed according to the prediction by a high-level density function theory (DFT) calculation and the isotope shift of deuterated samples. The joint analysis of the spectra obtained by the VCD and ordinary infrared (IR) measurements seems to be a useful way of using vibrational spectroscopy to investigate the hydrogen bonding system in solution.

Journal Article↗