Unsupervised Image Segmentation Using Hierarchical Clustering

In the analysis of a medical image database aimed at formulating useful knowledge for image diagnosis requires an unsupervised image processing technique without preconceived knowledge. In this paper, we propose a method for unsupervised image segmentation, which is suitable for finding the features contained in an image. A small region around each pixel is considered as a pattern vector, and the set of pattern vectors acquired from the whole image is classified using the hierarchical clustering technique. In hierarchical clustering, the classification of pattern vectors is divided into two clusters at each node according to the statistical criterion based on the entropy in thermodynamics. Results of the test image generated by the Markov random field (MRF) model and real medical images photomicrographs of a colon tumor are shown.     

Analysis of Spectral Reflectance Using Normalization Method from Endoscopic Spectroscopy System

Objective assessment of gastrointestinal mucosal color is extremely important in the endoscopic diagnosis of digestive tract disease. In this paper, we propose a method to clarify the spectral characteristics of gastric and colon cancer. A large number of spectral reflectance data of mucous membrane are measured by the endoscopic spectroscopy system (ESS) in the National Cancer Center Hospital East, Kashiwa, Japan and the Department of Internal Medicine, Self-Defense Force Center Hospital, Tokyo, Japan. We assume that early cancer appears primarily in the spectral data of short wavelength, because it is usually present in a superficial cell where short wavelength light is scattered more strongly than long wavelength light. To identify the features in the short wavelength components, the spectral reflectance was divided by the reflectance of a long wavelength. We investigated the possibility of distinguishing early cancer from normal spectral data through statistical analysis, employing the projection axis as the mean difference between them. Early cancer and normal spectral data were projected on the projection axis, and the Student’s T-test was applied to evaluate the mean of the distribution between these data.     

Diphenylprolinol Silyl Ether as a Catalyst in an Enantioselective,Catalytic Michael Reaction for the Formation of α,α‐Disubstituted α‐Amino Acid Derivatives

Direct and enantioselective : Diphenylprolinol silyl ether was found to catalyze the direct, asymmetric Michael reaction of 4‐substituted 2‐aryl‐2‐oxazoline‐5‐one and α,β‐unsaturated aldehydes, affording the chiral α,α‐disubstituted α‐amino acid derivatives with excellent enantioselectivity.

     

High-performance computing techniques for vortex method calculations

A fast vortex method has been developed by using a special-purpose computer, MDGRAPE-3. MDGRAPE-3, successor of MDGRAPE-2, has been applied to the same calculations (Sheel et al. in Comput. Fluids 36:1319–1326, 2007) and the improvement in speed was 1000 times faster when compared with the ordinary PC Xeon 5160 (3.0 GHz) for N = 10⁶. The simultaneous use of the fast multipole method, Pseudo-particle multipole method with the special-purpose computers gives further acceleration of vortex method calculations. In addition, performances and efficiency have been investigated carefully. Further possibility has been investigated carefully and compared the present result with the previous one.     

Color Conversion Method for Multiprimary Display Using Matrix Switching

The range of reproducible color, i.e., color gamut, of conventional three-primary display devices is sometimes insufficient for reproducing the natural color of an object through color imaging systems. A multiprimary display is being developed for the purpose of reproducing an expanded color gamut using more than three primary colors. In this paper, a color conversion method is proposed to reproduce the natural color by additive mixture of multiprimary colors. The multiprimary color signal in this conversion method is calculated from the three-dimensional color coordinates CIE-XYZ, considering the dynamic range of each primary color. Divided into some linear elements from the polyhedral color solid of the multiprimary display, the conversion considering the constraint of the dynamic range can be performed by simple calculation without iterative calculation or a huge three-dimensional look up table. A fast computation method with a two-dimensional look-up-table is also presented. Using the proposed method, the result of the color reproduction is experimentally demonstrated by a six-primary projection display.     

Estimation of Electrical Source Localization Using the Temporal Correlation between Magnetic Field Measurements

It is well known that an inverse problem of biomagnetic imaging is generally ill-posed. Recently several attempts using biocoherence have been reported, but the ill-condition is not considered in these previous methods. If the conventional reconstruction formula is under the ill-condition, the reconstruction problem is also ill-posed and the ill-posedness cannot be improved. In this paper, we propose an approach to estimate the location of current sources under the condition that sources of different positions have little or weak correlation. Our method is based on a well-known regularization method, the truncated SVD method. Compared with the conventional method, our technique allows accurate determination of the location of current sources because it improves the ill-posedness of the inverse problem. We carried out computer simulations using the half-space conducting model and confirmed the effectiveness of our method.     

Developments of magnetic-resonance-related spin chemistry in Japan

A review on the developments of the magnetic-resonance-related spin chemistry in Japan is presented. We describe how studies in this area started in Japan and developed into the flourishing state of the present. Important contributions made by Japanese spin chemists in the last two decades in three areas, namely, work on chemically induced dynamic electron polarization, excited states and controlling of photochemical reactions, are presented. More emphases are placed on the new developments in recent years, particularly new concepts and new methodologies.     

Chemiluminescence of NS radical produced by the reaction of active nitrogen with sulfur vapor and sulfur chloride

Kinetics of NS (B² Π → X²Π) emission produced by the reaction of active nitrogen with sulfur vapor or sulfur chloride (S₂Cl₂) has been studied as a function of the total pressure and of the concentrations of atomic nitrogen and sulfur. The B ²Π state of NS is selectively formed by the three-body recombination reaction of N ans S atoms, N(⁴S) + S(³P) + M →. NS(B ²Π) + M. The highest vibrational level of the B ²Π state observed is ν′ = 12, which gives a lower bound for the dissociation energy of 4.93 eV.