Photochemical regulation of the activity of an endonuclease BamHI using an azobenzene moiety incorporated site-selectively into the dimer interface

Endonuclease BamHI mutants having an azophenylalanine residue in the dimer interface (azoAla-BamHI) were synthesized; while the activity was almost suppressed using trans-azoAla-BamHI, the cis-isomer generated with photoirradiation recovered its intrinsic activity.     

Polarization-mode dispersion measurement by an optical time-domain reflectometer with polarimetry assuming backscattering by randomly oriented nonspherical particles

In previous work on polarization-mode dispersion (PMD) measurement with an optical time-domain reflectometer with polarimetry (p-OTDR), scatterers were assumed to be a cloud of small spherical particles in a fiber. We have found that the p-OTDR waveforms were fitted well by modified Mueller matrices, assuming scattering by a cloud of nonspherical particles. We realized a PMD measurement based on the p-OTDR Jones matrix eigenanalysis (JME) method. The measured PMD was consistent with that of JME standard measurement with transmission-type polarimetry.     

Measurement of Optical Constants of CVD-Diamond for Short-Wavelength Far-Infrared Lasers

A diagnostic system using short-wavelength far-infrared (FIR) lasers (40–70 m in wavelength) is now being developed for high density and large volume plasmas. In the wavelength region, a CVD-diamond is the excellent materials for optical windows of the laser and the plasma vessel and beam splitters of a multichannel interferometer. To design these optical elements, the optical constants (refractive index n, absorption coefficient and transmissivity T) of the CVD-diamond have been measured precisely by using FIR lasers of 48-, 57- and 71-m in wavelength. As an example, the result for 57.1511 m light is n = 2.383(1) ± 0.002, = 0.19 ± 0.05 cm^-1 and T = 97.5 ± 1.5% at 1.023 mm in thickness.     

Excitation and decay of the isovector giant monopole resonances via the 208Pb(3He,t p) reaction at 410 MeV

The excitation and subsequent proton decay of the isovector spin-flip giant monopole resonance (IVSGMR) is studied via the 208Pb(3He,t) reaction at 410 MeV. In the inclusive spectrum (60+/-5)% of the non-energy-weighted sum-rule strength for this 2 variant Planck's over 2h omega resonance was found in the region 29相似文献   

Supramolecular assemblies formed by new L-lysine derivatives of viologens

L-Lysine derivatives of viologens form supramolecular assemblies of fibers and ribbons in some aromatic solvents, and the charge separation reaction in these self-assembling systems proceeds with a similar efficiency to the MV2+ system.     

Fiber-optic ring-down spectroscopy using a tunable picosecond gain-switched diode laser

Visible and near-infrared laser light pulses were coupled into two different types of optical fiber cavities. One cavity consisted of a short strand of fiber waveguide that contained two identical fiber Bragg gratings. Another cavity was made using a loop of optical fiber. In either cavity ∼40 ps laser pulses, which were generated using a custom-built gain-switched diode laser, circulated for a large number of round trips. The optical loss of either cavity was determined from the ring-down times. Cavity ring-down spectroscopy was performed on 200 pL volumes of liquid samples that were injected into the cavities using a 100 μm gap in the fiber loop. A detection limit of 20 ppm of methylene blue dye in aqueous solution, corresponding to a minimum absorptivity of εC<6 cm^-1, was realized. PACS 42.62.Fi; 42.81.-i     

Effect of 90 deg ferroelastic twin walls on lattice dynamics of nanocrystalline tetragonal ferroelectric perovskites

A combined transmission electron microscopy (TEM) and Raman spectroscopy study has been performed on nanocrystalline Ba_0.9Sr_0.1TiO₃ (BST) crystals and tubes. TEM investigations revealed the existence of 90 deg ferroelastic twins in the materials. Raman spectra showed an obvious shoulder (∼750 cm^-1) from the broad band at ∼720 cm^-1 that nominally represents the quasimode of E(LO₄) and A₁(LO₃). The intensity of this shoulder increases with the twin population in the nanocrystalline materials, suggesting a correlation between the lattice dynamical characteristics and the long-range ferroelastic strain of the twin wall. The ferroelastic strain is mainly constrained along the c-axis of the BST unit cell, and the effect of this constraint is more pronounced in nanocrystalline materials than in bulks due to a significant wall volume ratio in twinned nano-materials. A₁ phonons showing collective ion dynamics along the c-direction could be then hardened by the strain, while E symmetry exhibiting vibrations perpendicular to the c-axis would be less affected. The theoretically predicted giant LO–TO coupling in tetragonal ferroelectric perovskites [18] suggests that the hardening of the softest A₁(TO₁) mode in A₁ symmetry is accompanied by that of the hardest A₁(LO₃) phonon. Consequently, the shoulder could be ascribed to the ferroelastic strain induced hardening of the quasimode with a considerable contribution from the A₁(LO₃) phonon. PACS 61.72.Ff; 63.22.+m; 77.80.Bh; 77.80.Dj     

Functional Fluorescence Labeling of Carbohydrates and Its Use for Preparation of Neoglycoconjugates

Abstract

New bifunctional reagents, 2-amino-6-carboxyethylpyridine and 2-amino-6-cyanoethylpyridine, were designed and synthesized in order to provide a novel procedure for preparation of neoglycoconjugates from fluorescence-labeled and purified sugar chains. Labeling of model sugar chains with these reagents was effected by reductive amination using BH₃.Me₂NH to give corresponding 6-carboxyethylpyridylaminated (CEPA-) and 6-cyanoethylpyridylaminated (CNEPA-) derivatives, which were readily purified by reversed phase HPLC. The reagent parts of the labeled products possess the functional groups which then serve as linkers for coupling with matrices such as proteins and polymers. A CEPA-derivative of glucose was directly coupled with the ε-amino group of a Lys derivative to give a neoglycoprotein model. CNEPA-sugars were hydrogenated to give 6-aminopropylpyridylaminated (APPA-) derivatives, which can then be readily used for the preparation of various types of neoglycoconjugates by use of appropriate spacers as exemplified by the coupling of APPA-maltotriose with bovine serum albumin (BSA), biotin, and acrylic acid. The reaction of APPA-maltotriose with succinimidyl 3-(3-nitro-2-pyridyldithio)propionate gave the corresponding amide to be used for a disulfide formation with BSA. Condensation with biotin was effected by use of N-hydroxysuccinimidobiotin. The conjugation of APPA-maltotriose with acrylic acid was carried out by use of 4-acryloyloxyphenyldimethylsulfonium methylsulfate to give the corresponding acrylamide, which can be used for the preparation of sugar-acrylamide copolymers.     

Internal waves in a two‐layer system using fully nonlinear internal‐wave equations

In order to understand the nonlinear effect in a two‐layer system, fully nonlinear strongly dispersive internal‐wave equations, based on a variational principle, were proposed in this study. A simple iteration method was used to solve the internal‐wave equations in order to solve the equations stably. The applicability of the proposed numerical computation scheme was confirmed to agree with linear dispersion relation theoretically obtained from variational principle. The proposed computational scheme was also shown to reproduce internal waves including higher‐order nonlinear effect from the analysis of internal solitary waves in a two‐layer system. Furthermore, for the second‐order numerical analysis, the balance of nonlinearity and dispersion was found to be similar to the balance assumed in the KdV theory and the Boussinesq‐type equations. Copyright © 2009 John Wiley & Sons, Ltd.