Reverse thin layer method for enhanced ion yield of oligosaccharides in matrix‐assisted laser desorption/ionization

A sample preparation method that is suitable for sensitive detection of underivatized oligosaccharides by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) has been investigated. As compared with the conventional dried‐droplet or ethanol (EtOH) recrystallization method, superior mass spectra in terms of ion yield and signal‐to‐noise (s/n) ratio were obtained when methanol (MeOH) was used as a solvent for the mixture of matrix and oligosaccharides. Based on these results, a new sample preparation method, named the ‘reverse thin layer method’, was developed. This method comprises two steps: first, complete drying of the oligosaccharide solution on the MALDI target plate; and second, deposition of the matrix dissolved in a small amount of MeOH. Using this method, a relatively homogeneous matrix crystal was generated and higher yields of both positive and negative ions were obtained from oligosaccharides compared with conventional methods. Notably, the method can be applied to various matrices including both solid and liquid matrices. Copyright © 2009 John Wiley & Sons, Ltd.     

Estimation of Synthesizing New Superheavy Elements Using Dynamical Model

Physics of Atomic Nuclei - For the success the synthesis of superheavy elements $$Z>118$$ , it is indispensable to clarify the fusion–fission mechanism, which includes a role of the...     

Photoelectrochemical properties of tungsten trioxide thin film electrodes prepared from facet-controlled rectangular platelets

The control of anisotropic crystal growth is critical for directing the orientation of crystal lattice planes, and it plays a key role towards understanding the effects of different planes on chemical reactions. Here, we report on the photoelectrochemical properties of plate-structured tungsten trioxide (WO₃) thin films prepared from facet-controlled rectangular platelets of hydrotungstite (WO₃·2H₂O) and tungstite (WO₃·H₂O), which are directly grown on tungsten substrates. The WO₃ thin films, prepared via WO₃·2H₂O platelets, show relatively stable current for photoelectrochemical water splitting and methanol oxidation. On the other hand, the photocurrent of the WO₃ thin films prepared via WO₃·H₂O platelets was significantly decreased during the photoelectrochemical oxidation of water, which is likely due to the accumulation of partially oxidized intermediates such as peroxo species on the surface. These results indicate that the surface nanostructures of WO₃ may have a significant influence on photoelectrode efficiency and selectivity for the catalytic oxygen evolution reaction.     

Perception and production boundaries between single and geminate stops in Japanese

The theory of relational acoustic invariance [Pickett, E. R., et al. (1999). Phonetica 56, 135-157] was tested with the Japanese stop quantity distinction in disyllables spoken at various rates. The questions were whether the perceptual boundary between the two phonemic categories of single and geminate stops is invariant across rates, and whether there is a close correspondence between the perception and production boundaries. The durational ratio of stop closure to word (where the "word" was defined as disyllables) was previously found to be an invariant parameter that classified the two categories in production, but the present study found that this ratio varied with different speaking rates in perception. However, regression and discriminant analyses of perception and production data showed that treating stop closure as a function of word duration with an intercept term represented the perception and production boundaries very well. This result indicated that the durational ratio of adjusted stop closure (i.e., closure with an added constant) to the word was invariant and distinguished the two phonemic categories clearly. Taken together, the results support the relational acoustic invariance theory, and help refine the theory with regard to exactly what form 'invariance' can take.     

Integration of the cleanup process: pretreatment of polycyclic aromatic hydrocarbons from diesel exhaust particles on silica gel beads in a microchannel.

This paper presents an integrated microfluidic system that performs cleanup for polycyclic aromatic hydrocarbons (PAHs) from diesel exhaust particles on silica gel beads in a microchip. A column chromatography phase was constructed by filling the silica gel beads into a microchannel that had a dam structure 25 microm high. The height of the dam structure was determined according to the rate of the wet etching. This work on the cleanup of PAHs from diesel exhaust particles showed that the microchip-based system has the same performance as the conventional method on the solid phase extraction column and has some advantages, such as less reagent consumption and shorter pretreatment time, over the conventional method.     

Free-to-bound radiative recombination in highly conducting InN epitaxial layers

We present a theoretical simulation of near-band-edge emission spectra of highly conducting n-InN assuming the model of ‘free-to-bound’ radiative recombination (FBRR) of degenerate electrons from the conduction band with nonequilibrium holes located in the valence band tails. We also study experimental photoluminescence (PL) spectra of highly conducting InN epitaxial layers grown by MBE and MOVPE with electron concentrations in the range (7.7×10¹⁷–6×10¹⁸) cm⁻³ and find that the energy positions and shape of the spectra depend on the impurity concentration. By modeling the experimental PL spectra of the InN layers we show that spectra can be nicely interpreted in the framework of the FBRR model with specific peculiarities for different doping levels. Analyzing simultaneously the shape and energy position of the InN emission spectra we determine the fundamental bandgap energy of InN to vary between E_g=692 meV for effective mass m_n0=0.042m₀ and E_g=710 meV for m_n0=0.1m₀.     

Global asymptotic stability of nonautonomous systems of Liénard type

This paper deals with nonautonomous Liénard-type systems. Sufficient conditions are given for the zero solution of the systems to be globally asymptotically stable. The main result is proved by means of phase plane analysis with a Liapunov function. Examples are included to contrast our theorem with results which were presented by Hatvani and Cantarelli. Some global phase portraits are also attached.     

Consideration of Femtosecond Radiation Generation on NewSUBARU Storage Ring

We studied on realization of short pulse gamma ray and X-ray simultaneously induced by a femtosecond laser on NewSUBARU storage ring. Based on the fact that the transverse dimensions of electron beam are much shorter than the longitudinal one, the laser light is arranged to collide the electron beam at a right angle to generate femtosecond pulse gamma ray, furthermore, the modulated part of the electron bunch gives rise to short pulse X-ray by synchrotron radiation from a downstream bending magnet. The temporal characteristic of the radiation is analyzed in this paper, as well as the performances are estimated.