Perspective to search for sub-eV neutral boson resonances with stimulated laser colliders

We present a novel approach to search for sub-eV neutral bosons coupling to two photons which can be candidates for dark fields in the universe. Similarly to conventional particle colliders, the search aims at detection of resonance states of these dark fields produced by photon-photon scattering, however, the interaction rate is enhanced by the stimulated decay of resonances into two photons under a background coherent laser field. We discuss the future experimental strategy to explore a large mass-coupling parameter space with high-intensity lasers.     

Modeling shear modulus distribution in magnetic resonance elastography with piecewise constant level sets

Magnetic resonance elastography (MRE) is designed for imaging the mechanical properties of soft tissues. However, the interpretation of shear modulus distribution is often confusing and cumbersome. For reliable evaluation, a common practice is to specify the regions of interest and consider regional elasticity. Such an experience-dependent protocol is susceptible to intrapersonal and interpersonal variability. In this study we propose to remodel shear modulus distribution with piecewise constant level sets by referring to the corresponding magnitude image. Optimal segmentation and registration are achieved by a new hybrid level set model comprised of alternating global and local region competitions. Experimental results on the simulated MRE data sets show that the mean error of elasticity reconstruction is 11.33% for local frequency estimation and 18.87% for algebraic inversion of differential equation. Piecewise constant level set modeling is effective to improve the quality of shear modulus distribution, and facilitates MRE analysis and interpretation.     

Generation of a quasimonoenergetic electron beam using a single laser pulse

The results of experiments are presented for a single laser pulse interaction with a very low density gas target under conditions when the generated wake wave is below the wave-breaking threshold and the laser pulse power is lower than the critical power for relativistic self-focusing. A quasimonoenergetic electron beam is found to be stably generated for various laser pulse intensity values by controlling the acceleration length.     

Gapless Excitation above a Domain Wall Ground State in a Flat-Band Hubbard Model

We construct a set of exact ground states with a localized ferromagnetic domain wall and with an extended spiral structure in a deformed flat-band Hubbard model in arbitrary dimensions. We show the uniqueness of the ground state for the half-filled lowest band in a fixed magnetization subspace. The ground states with these structures are degenerate with all-spin-up or all-spin-down states under the open boundary condition. We represent a spin one-point function in terms of local electron number density, and find the domain wall structure in our model. We show the existence of gapless excitations above a domain wall ground state in dimensions higher than one. On the other hand, under the periodic boundary condition, the ground state is the all-spin-up or all-spin-down state. We show that the spin-wave excitation above the all-spin-up or -down state has an energy gap because of the anisotropy     

Beckmann Fission of Some Fused Cyclobutanones: A New Entry into Indole-2-Acetonitriles and Benzo[b]thiophene-2-acetonitrile

Fused cyclobutanone derivatives have been utilized as intermediates in a variety of synthetic schemes.¹⁾ We are investigating the synthesis and ring opening reactions of cyclobutanones fused to indoles, benzo[b]furans, and benzo[b]-thiophenes, in part with the hope of discovering a novel method for introduction of two carbon atoms to such heteroaromatic systems. In this communication the synthesis and Beckmann fission²⁾ of the cyclobutanone derivatives fused to 1-benzoyl-indoles and benzo[b]thiophene are described. This provides a new entry into indole-2-acetonitriles³⁾ and benzo[b]thiophene-2-acetonitrile.⁴⁾     

The Complete Determination of the Minimum Distance of Two-Point Codes on a Hermitian Curve

This is a continuation of the previous papers [3, 4, 5]. We finish determining the minimum distance of two-point codes on a Hermitian curve. Masaaki Homma: Partially supported by Grant-in-Aid for Scientific Research (15500017), JSPS. Seon Jeong Kim: Partially supported by Korea Research Foundation Grant (KRF-2004-041-C00016)     

Fluorescence analysis of p-hydroxymethamphetamine in urine by thin-layer chromatography.

A highly-sensitive analytical method for the detection of p-hydroxymethamphetamine (pOHMA) in urine is presented. The proposed method combines liquid-liquid extraction with acetonitrile and solid-phase extraction by thin-layer chromatography (TLC) with oxidation using potassium hexacyanoferrate(III) and sodium hydroxide to detect the fluorophor of pOHMA. The detection limit for pOHMA is 10 ng (n = 3). The analysis of pOHMA in forensic samples is successfully performed, without interference from endogenous fluorophors, yielding concentrations in the appropriate range for methamphetamine abusers.