Synthesis and biological evaluation of peptide mimics derived from first extracellular loop of CCR5 toward HIV-1

Peptide mimics derived from the first extracellular loop of CCR5 bearing non-peptide spacers in place of Ala-Ala-Ala sequence in the peptide moiety were synthesized, and the effects of these compounds on the inhibition against HIV-1 were examined. Compound 2b having m-aminophenoxyacetic acid derivative as a non-peptide spacer significantly inhibited HIV-1.     

Optical phase locking among femtosecond subharmonic pulses

We stabilized the relative carrier-envelope phase slip among the pump pulse and its subharmonic signal and idler pulses in a femtosecond optical parametric oscillator, resulting in long-term phasecoherence among the pulses. The stabilized beat signal corresponding to the relative carrier-envelope phase slip among subharmonic pulses had an accumulated phase error of 0.24 rad in the 1-mHz-1-MHz region. The fluctuation of the beat frequency measured by a 1-s-averaged counter was less than 1 mHz in a 1480-s measurement.     

Preparation of 3-acetoacetylaminobenzo[b]furan derivatives with cysteinyl leukotriene receptor 2 antagonistic activity

Novel 3-acetoacetylaminobenzo[b]furan derivatives with a modified triene system at the 3-position were prepared through acylation of the 3-aminobenzo[b]furans with 5-methylisoxazole-4-carboxylic acid chloride followed by basic cleavage of the isoxazole ring and several of these compounds showed moderate cysteinyl leukotriene receptor 2 antagonistic activity.     

Nano-rod structure of poly(ethylenedioxythiophene) and poly(pyrrole) as created by electrochemical polymerization using anionic porphyrin aggregates as template

It was found that a one-dimensional rodlike structure of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) in water acts as a powerful template for electrochemical polymerization of ethylenedioxathiophene (EDOT) and pyrrole on an ITO electrode. Examination using CV and UV-vis spectroscopic examinations established that J-aggregated TPPS molecules are entrapped in the resultant poly(EDOT) and poly(pyrrole) films. SEM observation established that these monomers are electrochemically oxidized to grow up to a nanosized rodlike structure, reflecting the aggregation structure of TPPS. [structure: see text]     

Pressure-induced superconductor-insulator transition in the spinel compound CuRh2S4

We performed resistivity measurements in CuRh2S4 under quasihydrostatic pressure of up to 8.0 GPa, and found a pressure-induced superconductor-insulator transition. Initially, with increasing pressure, the superconducting transition temperature T(c) increases from 4.7 K at ambient pressure to 6.4 K at 4.0 GPa, but decreases at higher pressures. With further compression, superconductivity in CuRh2S4 disappears abruptly at a critical pressure P(SI) between 5.0 and 5.6 GPa, when it becomes an insulator.     

Solid-state 13C and 1H spin diffusion NMR analyses of the microfibril structure for bacterial cellulose

To obtain further information about the cause for the rather large splitting of the C4 resonance line into the downfield (C4D) and upfield (C4U) lines in CP/MAS ¹³C NMR spectra for native cellulose, ¹³C and ¹H spin diffusion measurements have been conducted by using different types of bacterial cellulose samples. In ¹³C spin diffusion measurements, the C4D resonance line is selectively inverted by the Dante π pulse sequence and the ¹³C spin diffusion is allowed to proceed from the C4D carbons to other carbons including the C4U carbons with use of the ¹³C4-enriched bacterial cellulose sample. The analysis based on the simple spin diffusion theory for the process experimentally observed reveals that the C4U carbons may be located at distances less than about 1 nm from the C4D carbons. In ¹H spin diffusion measurements, poly(vinyl alcohol) (PVA) films in which ribbon assemblies of bacterial cellulose are dispersed are employed and the ¹H spin diffusion process is examined from the water-swollen PVA continuous phase to the dispersed ribbon assemblies by the ¹³C detection through the ¹H–¹³C CP technique. As a result, it is found that the C4D and C4U carbons are almost equally subjected to the ¹H spin diffusion from the PVA phase, indicating that the C4U carbons are not localized in some limited area, e.g. in the surfacial region, but are distributed in the whole area in the microfibrils. These experimental results suggest that the C4U carbons may exist as structural defects probably due to conformational irregularity associated with disordered hydrogen bonding of the CH₂OH groups in the microfibrils.     

Median plane localization using a parametric model of the head-related transfer function based on spectral cues

To examine a simulation method for vertical sound localization, and to clarify which peaks and notches in head-related transfer functions (HRTFs) play a role as spectral cues, localization tests in the median plane were carried out using a parametric HRTF model, which is recomposed only of extracted spectral peaks and notches. The results show that the parametric HRTF recomposed using the first and second notches (N1 and N2) and the first peak (P1) provides almost the same localization accuracy as the measured HRTFs. Observations of the spectral peaks and notches indicate that N1 and N2 change remarkably as the source elevation changes, whereas P1 does not depend on the source elevation. In conclusion, N1 and N2 can be regarded as spectral cues, and the hearing system could utilize P1 as the reference information to analyze N1 and N2.     

X ray crystallography of (+)-(R)p methyl phenyl phosphoramidate of ethyl L-phenylalaninate

The absolute configuration of (+)-(R)_p methyl phenyl phosphoramidate of ethyl L-phenylalaninate $\text{1}$ was determined by X ray crystallography.