The effect of chromium substitution on the phase transition of lithium manganese spinel oxides

The phase transition of chromium substituted lithium manganese spinel oxide, LiCr_yMn_2−yO₄ was investigated by low-temperature powder X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and electrical resistivity measurements. The sample prepared at 820 °C resulted in lowering the transition temperature T_t with Cr composition y, whereas T_t of the sample prepared at 750 °C remained constant for 0≤y≤0.17 in LiCr_yMn_2−yO₄. This would be caused by a difference in distribution of the substituted Cr³⁺ ion in octahedral site depending on the preparation temperature. The phase transition was suppressed with increasing the amount of Cr content.     

Mutual-probability prediction and higher-order correlation effects among acoustic,light and electromagnetic waves in a video display terminal environment

A probabilistic signal processing method, with which is possible to get some methodological suggestion to the measurement method of correlative and/or accumulative effects in the compound environment of sound, light and electromagnetic (EM) waves is discussed. In order to extract various types of latent interrelation characteristics among wave environmental factors leaked from an actually operating video display terminal (VDT), an extended regression system model, hierarchically reflecting not only linear correlation information but also nonlinear correlation information, is first introduced, especially from a viewpoint of ‘relationism-first’. Then, through estimating each regression parameter of this model, some original evaluation methods for predicting a whole probability distribution form, from one another, are proposed. Finally, the effectiveness of the methods is experimentally confirmed, by applying them to the actual observed data leaked by a VDT with some television games. To cite this article: M. Ohta et al., C. R. Mecanique 333 (2005).     

Preparation and Characterization of 61,6n-DI-O-(α-D-Galactopyranosyl)Cyclomaltooctaoses

ABSTRACT

Four positional isomers of 6¹,6ⁿ-di-O-(D-galactopyranosyl)cyclomaltooctaoses (cG₈s, γ-cyclodextrins) (n = 2?5) were chemically synthesized using the trichloroacetimidate method. The desired compounds having two α-(1→6)-linkages were isolated from a mixture of configurational isomers by HPLC, and their structures were confirmed by ¹³C NMR spectroscopy and FAB-high resolution mass spectra (HRMS). The elution behavior of their four positional isomers on an ODS column by HPLC is discussed.     

Preparation and Characterization of Branched β-Cyclodextrins Having Manno-Oligosaccharide Side Chains Derived from Yeast Mannan and Study of Their Functions

Branched -cyclodextrins (-CDs) having manno-oligosaccharide side chains were investigated. Three kinds of monobranched -CDs and five kinds of dibranched -CDs were chemically synthesized using the trichloroacetimidate method. Their structures were analyzed by HPLC, MS, and NMR spectroscopies. The specific interaction between those compounds and mannose-binding lectins (Concanavalin A and Pisum sativum agglutinin) was investigated by inhibition tests of hemagglutinating activity and by using an optical biosensor of the IAsys apparatus with a resonant mirror detector. The results showed that all branched -CDs interactedwith lectins. The binding affinity was 6¹,6⁴-(Man₃)₂- 6¹,6⁴-(Man₂)₂- > 6¹,6⁴-(Man₄)₂--CD when the derivatives were compared on the basis of side chain length and 6¹,6³- 6¹,6⁴- > 6¹,6²-(Man₂)₂--CD when compared on the basis of side chain position.     

First functionalized MRI contrast agent recognizing vascular lesions.

A new MRI-contrast agent, EB-DTPA-Gd, that has an Evans Blue analogue as a sensing unit for endothelium lesions, was designed and synthesized. The agent also has diethylenetriamine-N,N,N',N",N"-pentaacetic acid-Gd complex (Gadolinium-DTPA) units, which have been used as detection units for T1-weighted MRI. The EB-DTPA-Gd was able to recognize and adsorb to the vascular endothelium-denuded region of porcine aorta, and to decrease the relaxation time of circumferential water's protons, making possible MR imaging of the endothelium-denuded region. The compound can be employed as a contrast agent for the imaging of vascular lesions using MRI.     

An approach to the spectrum structure of Dirac operators by the local-compactness method

The purpose of this paper is to investigate the spectra of the Dirac operator . The local compactness of is shown under some assumption on . This method enables us to prove that if as , then and to give a significant sufficient condition that or has a purely discrete spectrum.

     

Application of Ab initio calculations to nuclear internal conversion: Repulsion energies of highly charged HBr ions

Ab initio MO calculations were applied to the evaluation of repulsion energies in highly charged HBr ions. Net charges of H and Br atoms were obtained from the Mulliken atomic population, and repulsion energies were estimated by a simplified model based on the Coulomb repulsion. The repulsion energy of HBr⁸⁺ was calculated to be 71.5 eV.