[en] This paper reports on the current method in bone age determination which is based on a manual comparison of a hand radiograph with a series of patterns representative for a particular age and sex. Image analysis methods may increase the diagnostic accuracy and objectivity. The algorithm performs carpal bone feature extraction and is divided into two parts. The first deals with finding the region of interest (ROI) in a digitized 2,000 x 2,000 x 10-bit radiograph. After the image is rotated to a standard position, the ROI is determined. The histogram analysis and edge-enhancement method are applied to detect the bone tissues. After the ROI is thresholded, morphologic techniques are used to remove the ulna, radius, and metacarpals. The carpal bones remained intact. In the second part the following carpal bone parameters are obtained: number perimeters, surface area, compactness ratios, vertical and horizontal diameters, eccentricity, and pseudoconvexity coefficients

[en] Red pine sapwood transverse and radial surfaces were exposed to ultraviolet (UV) light for 3 to 40 days. Effect of UV irradiation on ultrastructural changes of cell walls were studied by scanning (SEM) and transmission (TEM) electron microscopy. SEM study of transverse sections showed that during initial stages of UV irradiation, lignin in cell corners and in the compound middle lamellae was preferentially degraded and that the radial middle lamellae substained a greater rate of UV degradation than did the tangential middle lamellae. Massive cell wall degradation, as indicated by cell wall thinning, did not occur until surfaces were exposed to UV light for more than 10 days. TEM study of radial cell wall surfaces indicated that lignin lining the warty layer was removed by UV irradiation in 3 days and that warts were destroyed by a UV irradiation in 7 days. UV irradiation of cell wall surfaces produced a substantial amount of water-soluble degradation products. After 30 days of UV irradiation, the S3 layer was totally removed and revealed the very fragile S2 layer. (author)