Development of a high-precision image-processing automatic measurement system for MRI visceral fat images acquired using a binomial RF-excitation pulse

Development of a rapid and accurate method for visceral fat measurement is an important task, given the recent increase in the number of patients with metabolic syndrome. In this study, we optimized the Fast Low Angle Shot (FLASH) sequence using a binominal radiofrequency excitation pulse, in which the acquisition time is short, and measured changes in the amount of visceral fat in subjects after a period of wearing clothes with a fat-reducing effect during walking. We solved the reproducibility problem associated with the number of slices, and developed automatic measurement software for high-precision separation and extraction of abdominal visceral fat images. This software was developed using intensity correction with the coil position, derivation of a threshold by histogram analysis and fat separation by template matching for abdominal images. The cross-sectional area of a single slice varies for every acquisition due to visceral organ movement, but the relative error largely converged for seven slices. The measured amount of abdominal fat tended to be consistent with changes in the body fat and waist circumference of the subjects. The correlation coefficients between automatic extraction using the measurement software and manual extraction were 0.9978 for subcutaneous fat and 0.9972 for visceral fat, showing very strong positive correlations. The consistency rates were 0.9502±0.0167 for subcutaneous fat and 0.9395±0.0147 for visceral fat, and the shapes of the regions were also extracted very accurately. These results show that the magnetic resonance imaging acquisition method and image processing system developed in this study are beneficial for measurement of abdominal visceral fat. Therefore, this method may have a major role in future diagnosis of metabolic syndrome.     

Vortex structures in nano-scaled superconducting networks

Using the de Gennes–Alexander equation, we have investigated the stable vortex structures in finite superconducting networks (10 × 10 holes) with disordered wires under an external magnetic field. Vortex structures change gradually with increasing magnetic field. For the network with a disordered wire at the edge, vortices are not pinned disordered hole, but enter into the network at the holes with the disorder. But for the network with two disordered wires, the vortex enters at the hole between two disordered wires. This behavior can be considered as the result of the nonlocality of superconductivity.     

Miniaturized 90° light path conversion device fabricated from UV-curable resin for optical interconnection

A new 90° light path conversion device incorporating a core element and a hybrid comb-clad that combines air and polymer components is proposed for optical interconnection. The device has a large refractive index difference (Δn) between the core and the hybrid comb-clad, which enables a small curvature radius. Extension to an array of M layers × N channels is straightforward. Ray-tracing simulations indicate that the bending loss is as small as 0.21 dB at the small curvature radius of 0.25 mm. Prototypes were fabricated by the photomask transfer method from two types of UV-curable resin; these prototypes exhibited 90° bending loss of 1.65 dB at a core curvature radius of 0.25 mm.     

Simulation of the trajectory of a punted rugby ball taking into account the asymmetrical pressure distribution caused by the seams

Abstract  

This paper describes the effect of the seams of a rugby ball on the side force and the flight trajectory of the punted kick. Measurement of the aerodynamic force on a non-spinning rugby ball reveals that the side force coefficient depends on the position of the seam as well as the angle of attack. It was found from pressure-sensitive paint measurements that the seam of the ball is the trigger for initiating low pressure when the seam is situated around 60° from the stagnation point. The flight trajectory of the fluctuating ball can be obtained by numerically integrating the six degree-of-freedom non-linear equations of motion. It was shown that a slower spinning ball fluctuates from side to side during flight because of the asymmetrical pressure distribution on the sides of the ball.     

Effects of recording wavelength on three-dimensional vector holograms in photoreactive liquid crystal composites

Effects of recording wavelength on the recently proposed (Sasaki, 2008) three-dimensional vector holograms, in which the optical anisotropy is three-dimensionally modulated, are presented experimentally and theoretically. The polarization states of the interference light are three-dimensionally modulated due to both the polarization interference and optical anisotropy in the recording medium. These spatial distributions of the polarization states and the resulting diffraction properties in the three-dimensional vector holograms are strongly dependent on the recording wavelength. Theoretical consideration based on the finite-difference time-domain (FDTD) method reveals the mechanism of the optical characteristics of the three-dimensional vector holograms recorded by various kinds of light sources with different wavelengths.     

Nondestructive analysis of silver in gold foil using synchrotron radiation X-ray fluorescence spectrometry.

Small particles of gold foil detached from an indoor decoration might be important evidence to associate a suspect with a crime scene. We have investigated the application of elemental analysis using synchrotron radiation X-ray fluorescence spectrometry to discriminate small particles of gold foil. Eight kinds of gold foil samples collected in Japan were used in the experiments. As a result of synchrotron radiation X-ray fluorescence spectrometry, only two elements, gold and silver, were detected from all gold foil samples. The intensity ratios of AgKalpha/AuLalpha showed good correlation with the content ratios of Ag/Au. The variation of intensity ratio within a same sample was sufficiently small compared with those of different samples. Therefore the comparison of this intensity ratio can be an effective method to discriminate small particles originating from different types of gold foil.     

Bioelectrocatalytic endpoint assays based on steady-state diffusion current at microelectrode array

Highly reproducible bioelectrocatalytic endpoint assays are described. The method is based on a complete redox conversion of a substrate to a redox mediator with a corresponding redox enzyme and an amperometric detection of the reduced mediator on a diffusionally independent microelectrode array. The current reaches a steady state within a few seconds and is proportional to the number of the integrated microelectrodes. The method has successfully been applied to histamine detection at micro-molar level and glucose detection at milli-molar level.     

A variational problem for affine connections

We give a variational problem for affine connections which characterizes the Riemannian connection of an Einstein metric of negative scalar curvature. Received: 10 May 2005; revised: 25 July 2005     

Forensic discrimination of sheet glass by a refractive-index measurement and elemental analysis with synchrotron radiation X-ray fluorescence spectrometry.

Measurements of the refractive index (RI) and elemental analysis using synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) were applied to the forensic discrimination of sheet-glass samples from different origins. The refractive index was calculated from the matching temperature at which the glass fragments became invisible in silicone oil. Fragments smaller than 1 mm in maximum diameter were taken from each of 11 sheet glasses and subjected to analysis by SR-XRF. The XRF spectrum of these samples indicated that a comparison of 6 elements (Ca, Fe, Sr, Zr, Ba and Ce) was useful for the discrimination of sheet glasses. Cluster analysis was performed using 33 sets of SR-XRF data obtained by triplicate measurements for the 11 glasses. Comparing 528 pairs among 33 samples, 515 pairs could be correctly discriminated. The number of indistinguishable pairs could be reduced from 36 to 4 by comparing the SR-XRF data. Elemental analysis by SR-XRF could provide small glass fragments with a more evidential value than the solely measurement of only RI, through a significant improvement of the discrimination capability.