Indomethacin sustained-release suppositories containing sugar ester

We prepared indomethacin (IM) sustained-release suppositories using sugar ester (SE) as an additive. The suppositories were prepared by the fusion method with IM, SE, and Witepsol H-15 (H-15) and their availabilities in vitro and in vivo were evaluated mainly by the drug release test and the absorption test in rabbits, respectively. The softening point of the suppositories increased with increasing SE content. In the release test with the Muranishi method, slow-release profiles were obtained when the SE content was more than 52.5%. The absorption of IM from these suppositories, however, was very little. In the other release test, e.g. immersion method with gauze, all of the suppositories with SE showed slow-release profiles, and the drug release rates clearly depended on the SE content. The drug was released from the suppositories by the following leaching-type mechanism proposed by Higuchi. The suppository with a 30% SE content showed a sustained-plasma level of IM, but the other suppositories did not. It was concluded that an appropriate content of SE (i.e. 30%) in the suppository base was required to obtain sustained-release because it reasonably regulated the infiltration of rectal fluid into the suppository and the mechanical strength of the suppository against disintegration.     

Reaction between cerium trifluoride and elemental fluorine

Reactions between cerium trifluoride and elemental fluorine have been examined by means of the kinetic and crystallographic method. The reactions were performed at 503–573 K under fluorine pressures of 6.7–26.7 kPa for reaction time up to 3 h. Two kinds of CeF₄ were synthesized by controlling the reaction condition. One is the metastable CeF₄-I synthesized at 523–538 K which returns to CeF₃ to release elemental fluorine, and the other is the stable CeF₄-II obtained at temperatures higher than ca. 540 K, which never returns to CeF₃. X-ray diffraction–Rietveld analysis revealed that the structure of CeF₄-I and CeF₄-II were monoclinic structure (C12/c1, Z=12, CeF₄-I/CeF₄-II: a₀, 1.26 nm/1.25; b₀, 1.06/1.05; c₀, 0.82/0.82; β, 126.1/126.3°; cell volume, 8.91×10⁻²⁸/8.78×10⁻²⁸ m³) and the cell volume of the CeF₄-I was 1.4% larger than that of the CeF₄-II. Bond lengths between Ce and F in CeF₄-I were somewhat longer than those in CeF₄-II. When CeF₄ and NaCl were put separately in the reaction container, CeF₄-I changed to CeF₃ with converting NaCl to NaF, however, CeF₄-II never reacted with NaCl.     

Comparison of escape depths between Auger electron and disappearance potential spectroscopy electron

The escape depths of the characteristic electrons of the Auger electron and the quasielastically reflected electron were determined by Auger electron spectroscopy (AES) and disappearance potential spectroscopy (DAPS), respectively, for a Cr overlayer onto Ti and Fe substrates. For the case of Cr on Fe, in-situ measurements of AES and DAPS were carried out. From the results, the mean free paths of 455, 575 and 710 eV electrons through Cr were obtained as 9.6, 13 and 15 Å, respectively. The attenuation length of a 2.5 keV primary electron of AES through Cr was also obtained and the value was 62 Å. In addition, the mean free paths of electrons with the same energy depend on the scattering materials of Cr, Mo and W (material dependence). The phenomena are useful for a quantitative electron spectroscopy of surfaces.     

The development of grain-oriented silicon steel with high permeability

We explain the theoretical background, uses and new development of grain-oriented silicon steel with high permeability using A1N as a grain growth inhibitor.New production techniques have made it possible to get superior core loss values; for example, 0.99 W/kg at 1.7 Tesla and 50 Hz (0.30 mm thickness). The presence of A1N precipitated being controlled in the size of about 300 Å or under and in adequate distribution and quantity in the steel is very important for developing secondary grains with high permeability.Core loss improvements on actual transformers using high permeability materials are approximately 10–25% in wound type pole transformers and 5–20% in laminated type large transformers.     

Competition of static stripe and superconducting phases in La(1.48)Nd(0.4)Sr(0.12)CuO(4) controlled by pressure

We have investigated the pressure effect on T(c) and the Hall coefficient in the static stripe-ordered phase of La(1.48)Nd(0.4)Sr(0.12)CuO(4) crystal under hydrostatic pressure. We found a dramatic change of the Hall coefficient and an abrupt increase of T(c) at low pressure of about 0.1 GPa. The results are indicative of a transition from one- to two-dimensional charge transport, associated with the suppression of low-temperature-tetragonal (LTT) phase. From the uniaxial pressure measurements it turns out that the observed critical change is induced primarily due to the in-plane compression of the CuO(2) planes which would make the pinning potential of the LTT lattice distortions weaker.     

Spectrum analysis of induction voltage from walking human body

Human body is charged during walking. Continuous monitoring of the body potential has been made using an induction electrode set on ceiling of a room. The body voltage estimated from the induced voltage was a few hundred volts and dependent on material of shoes, as expected. The induced voltage varied periodically while walking and the waveform was different depending on examinees or manner of walking, even the same footwear was used. In this study, spectrum analysis was made on the acquired voltage, and frequency component was compared. The voltage spectrum of 4 different persons, and 3 different walking patterns of one person were obtained, and their correlation was compared. The results indicate that the spectrum was different depending on the examinees. Among the tested 4 examinees, personal identification was possible using the correlation of the induced voltage while walking. This novel contactless body potential monitoring method can be applied to many new fields such as medical practice and food factory.     

Unexpected chain length dependence on a chiral memory effect of ‘meta-ethynylpyridine’ oligomers

The chain length dependence involving a chiral memory effect of 2,6-pyridylene ethynylene oligomers ‘meta-ethynylpyridines’ was investigated. The meta-ethynylpyridine oligomers associated with octyl β-d-glucopyranoside form a helical complex giving induced CD; the induced chirality could be memorized with the help of Cu(OTf)₂ as an additive. Contrary to our expectations, the study of the length dependence revealed that the 12-meric oligomer showed a more sustainable chiral memory effect than those observed in both of the shorter 6-meric and longer 18-meric oligomers.     

The stability of the modified plane Poiseuille flow in the presence of a transverse magnetic field

The stability against small disturbances of the pressure-driven plane laminar motion of an electrically conducting fluid under a transverse magnetic field is investigated. Assuming that the outer regions adjacent to the fluid layer are electrically non-conducting and not ferromagnetic, the appropriate boundary conditions on the magnetic field perturbations are presented. The Chebyshev collocation method is adopted to obtain the eigenvalue equation, which is then solved numerically. The critical Reynolds number R_c, the critical wave number α_c, and the critical wave speed c_c are obtained for wide ranges of the magnetic Prandtl number P_m and the Hartmann number M. It is found that except for the case when P_m is sufficiently small, the magnetic field has both stabilizing and destabilizing effects on the fluid flow, and that for a fixed value of M the fluid flow becomes more unstable as P_m increases.