Previously, we developed the phased tracking method [H. Kanai et al.: IEEE Trans. Ultrason. Ferroelectr. Freq. Control 43 (1996) 791] for measuring the minute change in thickness during one heartbeat and the elasticity of the arterial wall. By comparing pathological images with elasticity images measured with ultrasound, elasticity distributions for respective tissues in the arterial wall were determined. We have already measured the elasticity distributions for lipids and fibrous tissues (mixtures of smooth-muscle and collagen fiber) [H. Kanai et al.: Circulation 107 (2003) 3018]. In this study, elasticity distributions were measured for blood clots and calcified tissues. We discuss whether these elasticity distributions, which were measuerd in vitro, can be used as reference data for classifying cross-sectional elasticity images measured in vivo into respective tissues. In addition to the measurement of elasticity distributions, correlations between collagen content and elasticity were investigated with respect to fibrous tissue to estimate the collagen and smooth-muscle content based on elasticity. Collagen and smooth-muscle content may be important factors in determining the stability of the fibrous cap of atherosclerotic plaque. Therefore, correlations between elasticity and elements of the tissue in the arterial wall may provide useful information for the noninvasive diagnosis of plaque vulnerability.

The phased tracking method was developed for measuring the minute change in thickness during one cardiac cycle and the elasticity of the arterial wall. By comparing elasticity images measured by the phased tracking method with the corresponding pathological images, the elasticity distribution for each tissue in the arterial wall was determined. We have already measured the elasticity distributions for lipids, fibrous tissues (mixture of smooth-muscle and collagen fiber), blood clots and calcified tissues. From these previous studies, it was found that arterial tissues can be classified into soft tissues (lipids and blood clots) and hard tissues (fibrous tissue and calcified tissue) on the basis of their elasticity. However, it was difficult to differentiate lipids from blood clots and also fibrous tissue from calcified tissue. In this study, we investigated how to improve the tissue classification of the arterial wall using statistical properties of the elasticity distribution of each tissue.

[reaction: see text] An efficient synthesis of the C10-C31 (BCDEF ring) portion of pinnatoxin A has been achieved. The key step is a highly stereoselective construction of the dispiroketal (BCD ring) system employing an intramolecular hetero-Michael reaction of a reversibly formed hemiketal alkoxide through the use of LiOMe.

SnS and SnSe are renowned energy materials that are applied for photoelectric and thermoelectric conversions owing to their suitable band gap, close to 1 eV, and superior figure of merit (ZT), larger than 0.1. In this paper, high-quality layered SnX (X = S, Se) crystals have been successfully grown by the chemical vapor transport (CVT) method. The crystal structure and band structure of SnX are studied, and their photoelectric and thermoelectric properties are characterized. In Raman measurement, four vibration modes with distinct angle-polarization dependence are simultaneously detected by both SnS and SnSe, verifying their similar orthorhombic layered structure with in-plane anisotropy. In-plane anisotropy of band-edge and interband transitions along a and b axes has also been measured experimentally using polarized thermoreflectance (PTR) from 0.7 to 5 eV. The anisotropic band edges of layered SnX (X = S, Se) are well matched and reproduced by first-principles calculation. Hall-effect and thermoelectric measurements revealed that SnX are p-type semiconductors with a high carrier density, larger than 10 17 cm −3 . According to the measurement results of the surface photovoltaic (SPV) response and ZT value, layered SnS can have a superior SPV (8.5 μV/μW) response ∼12× higher than that of SnSe, while SnSe has a ZT of 0.16, ∼4× larger than that of SnS in SnX (X = S, Se). Layered SnSe and SnS could possess great feasibility for application in thermoelectric power generation and solar energy conversion.

No abstract