1,4:3,6-Dianhydrohexitol nitrate derivatives. I. Synthesis and antianginal activity of alkylpiperazine derivatives

A series of 5-deoxy-5-(4-substituted piperazin-1-yl)-1,4: 3,6-dianhydro-L-iditol 2-nitrates was prepared and evaluated for oral anti-ischemic activities. Inhibition of lysine-vasopressin-induced T-wave elevation in the electrocardiogram (ECG) of rats (angina pectoris model) served as a primary assay. Optimum activity was observed for the compounds with the aryl-heteroatom (O,S, or N)-propyl group. Among them, the phenylthiopropyl-substituted compound 13 exhibited the most potent activity. Furthermore, intraduodenal administration (i.d.) of 13 tended to decrease left ventricular end-diastolic pressure (LVEDP) in a propranolol-induced heart failure model (dogs) and showed a potent protective effect against reperfusion arrhythmia in rats. Thus, 13 (KF 14124) is under further study as an orally active nitrate.     

Development of RYUGA for three-dimensional dynamic visualization of molecular dynamics results

We have developed a new computer graphics (CG) code RYUGA for three-dimensional dynamic visualization of molecular dynamics (MD) results. The applicability of RYUGA for visualizing and analyzing the dynamics of atomic motions in various materials was demonstrated. RYUGA supports various functions, such as solid-modeling CG pictures (called the CPK model), CG animation of the MD results, Miller plane cutting of crystal structures, building graphs, etc., similar to other CG codes for MD simulation. In addition, RYUGA has a number of advantages as follows: (i) a perspective is employed for drawing CG pictures, (ii) three-dimensional trajectories of atoms can be constructed, (iii) an operator can travel inside the materials, (iv) graphic speed and animation speed are enhanced because of the specific algorithms, and (v) it works on any workstations, moreover even personal computers with a UNIX operating system and an X window system are available.     

Inhibition of deterioration of plastics by hydroaromatics

Based on our previous works concluding that the addition of hydrogen-donating hydroaromatics is effective in inhibiting the deterioration of hydrocarbons, heavy hydroaromatics from petroleum (HHAP) that were produced by hydrogenating highly aromatic heavy oil containing partly hydrogenated condensed aromatic rings were examined by the addition to high-density polyethylene (PE), isotactic polypropylene (PP), and poly(vinyl chloride) (PVC, MW: 1300) after confirming its prominent hydrogen-donating ability. The following results were obtained by the deterioration tests and melt-flow tests: (1) Clear inhibiting effects could be found on preservation of elongation and tensile strength by the addition of 0.1% and 0.5% of HHAP to PE. (2) Cross-linking of PE was restricted by the addition of HHAP. (3) Obvious effects could be found on preservation of elongation and tensile strength by the addition of 0.5% of HHAP to PP, but 0.1% of HHAP was not so effective. (4) Melt-flow rate of PP at 270°C supported the results of the deterioration tests at 120°C. (5) Color changes were remarkably improved by the addition of HHAP to PVC (at 160°C, 140 min). From these results, hydrogen donation from hydroaromatics can be considered effective in inhibiting the deterioration of PE, PP, and PVC.     

Gelatin microspheres crosslinked with γ‐ray: Preparation,sorption of proteins,and biodegradability

A new type of gelatin microspheres was manufactured with the crosslinking method by using γ‐ray irradiation. Microspheres thus obtained were characterized by microscopic observation and enzymatic degradability. The mean diameter of the microspheres was in the range from 2.4 to 3.6 μm and the size distribution was quite small. The size decreased with increasing the shear rate of the emulsifier used in the preparation and was not affected by the radiation dose. The enzymatic degradability decreased with increasing the radiation dose and decreasing the gelatin concentration of the microsphere. In other words, the rate of the enzymatic decomposition of microspheres can be controlled by these two parameters. These trends were consistent with our previous results for the gel sheet made of gelatin. Their sorption of proteins was also investigated with the use of three types of proteins labeled by fluorescent pigment. From the fluorescence micrographs, it was observed that the gelatin microspheres adsorbed only proteins having the opposite charge. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3083–3087, 2004     

Edge density profile variation during a magnetic axis shift in the CHS heliotron/torsatron

Edge density profiles were measured during natural and forced magnetic axis shifts in the lowaspect-ratio heliotron/torsatron CHS, using an 8 keV fast neutral lithium beam probe. The Shafranov shift of the magnetic axis (and hence the dislocation of the LCFS) that was negligible for a low density ECH discharge became substantial (4.5 cm) for a high density NBI discharge (n _e2.5× 10¹³cm^–3) and the corresponding radius of the LCFS increased about 1.2 cm in major radius compared to the vacuum case. For NBI discharges with different settings of the vacuum magnetic axisR _ax (fixed during the discharge), the measured edge density profiles indicated reasonable agreement between the theoretically and experimentally obtained LCFS radii for 90 cm <R _ax<101.6cm, while forR _ax<90 cm the measured radius was 10% larger than expected. When a change ofR _ax from 94.7 cm to 89.9 cm during a discharge was imposed externally, a well behaved plasma boundary moved inward smoothly by about 7.5 cm, while the steepness of the edge density profile changed for different values ofR _ax. The steepest profile was attained forR _ax=92.1 cm when the highest energy content and average density were achieved.     

Magnetoresistance in Tunnel Junctions Made of Epitaxially Grown Manganate Films with 1.6-nm-Thick Barriers

Magnetic tunnel junctions with barrier thicknesses of either 1.6 or 2.4 nm have been fabricated from epitaxially grown La_0.8Sr_0.2MnO₃/SrTiO₃/La_0.8Sr_0.2MnO₃ trilayers. For the junctions with 1.6-nm-thick SrTiO₃, tunneling magnetoresistance (TMR) as large as 150% was observed at 5 K. A small TMR was observed even at 270 K, which is close to the ferromagnetic Curie temperature (290 K) of the La0.8Sr_0.2MnO₃ film. Besides tunneling conduction, parallel semiconduction through the SrTiO₃ barrier appeared to exist, and became dominant at high temperatures, reducing the TMR ratio and operating temperature, especially for thicker SrTiO₃ barriers. The SrTiO₃ barrier thickness is the key to improving TMR characteristics, and fabricating a sufficiently thin and uniform barrier layer is essential for achieving a large TMR and a high operating temperature.