Crystal structure of polysulfonamides

Structures of poly(alkylene-1,3-benzenedisulfonamide)s [? HN(CH₂)_mNH? O₂SC₆H₄SO₂? ]_n (PMm: 2 ≤ m ≤ 6) were studied by x-ray diffraction and infrared spectroscopy. The crystal structure of PB6 is monoclinic, space group C2/m? C_2h³, with a = 7.70 Å, b = 7.76 Å, c (molecular axis) = 14.1 Å, and β = 117°. Two mirror-image molecules repeating with two monomeric units in an identity period 28.2 Å occupy the same lattice site with equal probability. The alkylene chains assume the planar zigzag conformation, which is the structure isomorphous with PB4. An intermolecular hydrogen bond is formed between each NH group and one of the two O = S groups of the corresponding SO₂ unit. The c axis tends to tilt from the fiber axis by an inclination angle of about 3° around the b axis.     

Long life potential resonances in 16O12C scattering from an l-dependent absorptive potential

A semiclassical theory is applied to elucidating essential features of ¹⁶O¹²C scattering from an l-dependent absorptive potential. Long life potential resonances do occur for surface partial waves and cause an enhanced backangle differential cross section and a typical interference pattern at intermediate angles. The almost constant frequency of the backangle oscillation is, however, essentially due to the narrow l-window characteristic of surface transparent potentials.     

Grain boundary relaxation in fine-grained magnesium solid solutions

Grain boundary relaxation at elevated temperatures in fine-grained pure magnesium and Mg–Al solid solutions was investigated by measuring damping capacity at low frequencies. A sharp increase in damping capacity caused by grain boundary relaxation was observed at above a certain temperature. The onset temperature depended on aluminum content; the onset temperature increased with aluminum content. It was demonstrated that aluminum was effective in suppressing grain boundary relaxation in magnesium alloys. However, additional measurement of the damping capacity of a dilute Mg–Y alloy revealed that yttrium was more effective in suppressing grain boundary relaxation.     

Wavelength stabilization of a distributed Bragg reflector laser diode by use of complementary current injection

We have demonstrated wavelength stabilization in an 821-nm AlGaAs three-section tunable distributed Bragg reflector (DBR) semiconductor laser diode (LD) that consists of active, phase-controlled, and DBR regions. We injected two separate, complementary currents into the active and the phase-controlled regions in the DBR-LD to suppress wavelength shift. This modulation method was applied to the LD fundamental wave in a second-harmonic-generation (SHG) laser, and the oscillating wavelength was maintained within the phase-matching acceptance range of the SHG device during modulation. A peak blue-violet light power of 62 mW was obtained for the ideal modulation waveform.     

Positive muon spin precession in magnetic oxides MnO and V2O3; local fields and phase transition

Muon spin precession is observed in the ordered state of antiferromagnetic oxides MnO and V₂O₃. An anomalous temperature dependence of muon precession frequency and the absence of critical behavior atT _N are found in MnO and a hysterisis of the transition temperature is observed in V₂O₃. These results are explained in terras of the crystal distortion of these materials belowT _N.We would like to thank Dr. T. Suzuki, Dr. S. Takagi, Dr. Y. Kuno and Dr. C.Y. Huang for their help in the measurements, and Dr. K. Kosuge and Dr. S. Kachi for providing the specimen of V₂O₃. We are grateful to the financial support from Japan Society for Promotion of Science.     

A note on diffraction phenomena in the inelastic scattering of complex nuclei

We illustrate how oscillations in angular distributions for inelastic scattering of heavy ions can be produced by diffraction effects arising from the variation of the excitation amplitudes.     

Synthesis of optically active forms of ipsdienol and ipsenol : The pheromone components of ips bark beetles

(R)-(-)-Ipsdienol 1″ and its antipode 1' were synthesized from (R)-(+)-glyceraldehyde acetonide and (R)-(+)-malic acid, respectively. This established the S-configuration of the naturally occurring (+)-ipsdienol. A new synthesis of (R)-(+)-ipsenol 2″ and its antipode 2' was also described. Chiral epoxides were shown to be useful intermediates for the synthesis of these chiral alcohols.     

Kinetic study on the elastic change of vascular endothelial cells on collagen matrices by atomic force microscopy

The elasticity of vascular endothelial cells (HUVEC) was measured with an atomic force microscopy (AFM, Olympus), and analyzed by applying the Hertz model, and those data were compared with ones reported by us previously. The latter elasticity data were measured with AFM Instruments (Seiko) on the basis of the Young's modulus of gelatin gel, which was obtained from the measurement with a tensile tester. The elasticity of HUVEC was concluded to depend on the culture period. The elasticity of the cells cultured on type IV collagen for longer than 4 days led to average elasticity values higher than ca. 10(4)Pa. Moreover, the scattered values of elasticity decreased eminently in the AFM measurement of the cells at room temperature. A few cells, however, appeared to adhere long and tensely on matrix, which seems to one of reasons for relatively high elasticity in our previous works. The possibility of such high elasticity was considered to change in cell adhesion, anchoring on matrix during a long culture period.     

Simultaneous determination of urinary hippuric acid, o-, m- and p-methylhippuric acids, mandelic acid and phenylglyoxylic acid for biomonitoring of volatile organic compounds by gas chromatography-mass spectrometry

A sensitive and precise method for the simultaneous determination of hippuric acid, o-, m- and p-methylhippuric acids, mandelic acid and phenylglyoxylic acid, which are major urinary metabolites of toluene, o-, m- and p-xylenes, styrene and ethylbenzene, respectively, was developed. These metabolites were converted into their methyl ester derivatives with methanol in hydrochloric acid, and then quantitated by gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring using a DB-1 capillary column. The injected compounds were quantitatively and reproducibly resolved within 19 min with a detection limit of 8-27 pg. The calibration curves were linear in the range of 0.05-25 μg for each compound, with correlation coefficients above 0.9999. This method was successfully used to analyze small amounts of both rat and human urine samples without any interference from coexisting substances. Overall recoveries of these compounds spiked in urine samples were 92-104%. The analytical results of the contents of these metabolites in the rat and human urine samples are presented.