[Effects of locally used SD zinc, SD silver and skin transplantation on the combined radiation-burn injury in the rat]

Effects of local use of sulfadiazine (SD) zinc, SD silver in the wound and skin transplantation on the combined injury of 6 Gy radiation and 15% TBSA burn were investigated in the present study. In the three groups of SD zinc or SD silver plus skin grafting at 15 d after combined injury and SD zinc alone, the 15-day survival rates were 63%, 69% and 75% respectively, and significantly higher than that of control group (42%). The repair time of burn wound was shorter and the number of white blood cells was lower than that of control. Animals in the group of local use of SD silver followed by skin grafting on the 7th day all died, but all of the animals survived when the skin grafting was performed after 15 days. These results suggested that SD zinc and SD silver showed some therapeutic effects on the combined radiation-burn injury. In critical phase of the combined injury, surgical operation should be prohibited. However, in the recovery phase, skin transplantation could be performed.

Changes of immune functions after radiation, burns and combined radiation-burn injury in rats

The changes of several immune functions were observed in rats after they were inflicted with 6 Gy gamma rays irradiation, 15% TBSA full thickness brun and the combination of the 2 injuries. It was found that the functions of thymocytes and splenoctyes suffered the most severe suppression in the 24th to 72nd hour after radiation injury and began to recover on the 7th day. In the rats with burn injury, the suppression on thymocytes and splenocytes were significantly less severe than that after radiation and recovered more rapidly. The effects of combined radiation-burn injury showed several characteristics. The suppression on the thymocytes was more severe with slower recovery as compared with that after single radiation injury only. The suppression on the splenocytes as a whole was similar to that after single radiation injury, but in the early stage after combined injury, the suppression was far more severe than that after radiation. Escharectomy and skin grafting on the burn wounds on the 1st day after combined injury could accelerate the recovery on both the thymocytes and splenocytes. Our findings indicated that the severity of the suppression on the immune functions due to combined radiation-burn injury might depend on the size of the burn wounds.

A perceptually motivated three-component image model-part II: applications to image compression

For past I see ibid., vol.4, no.4, p.405 (1995). The use of the image model of Part I is investigated in the context of image compression. The model decomposes the image into a primary component that contains the strong edge information, a smooth component that represents the background slow-intensity variations, and a texture component that contains the textures. The primary component, which is known to be perceptually important, is encoded separately by encoding the intensity and geometric information of the strong edge brim contours. Two alternatives for coding the smooth and texture components are studied: entropy-coded adaptive DCT and entropy-coded subband coding. It is shown via simulations that the proposed schemes, which can be thought of as a hybrid of waveform coding and feature-based coding techniques, result in both subjective and objective performance improvements over several other image coding schemes and, in particular, over the JPEG continuous-tone image compression standard. These improvements are especially noticeable at low bit rates. Furthermore, it is shown that a perceptual tuning based on the contrast-sensitivity of the human visual system can be used in the DCT-based scheme, which in conjunction with the three-component model, leads to additional subjective performance improvements.

A perceptually motivated three-component image model-Part I: description of the model

Some psychovisual properties of the human visual system are discussed and interpreted in a mathematical framework. The formation of perception is described by appropriate minimization problems and the edge information is found to be of primary importance in visual perception. Having introduced the concept of edge strength, it is demonstrated that strong edges are of higher perceptual importance than weaker edges (textures). We have also found that smooth areas of an image influence our perception together with the edge information, and that this influence can be mathematically described via a minimization problem. Based on this study, we have proposed to decompose the image into three components: (i) primary, (ii) smooth, and (iii) texture, which contain, respectively, the strong edges, the background, and the textures. An algorithm is developed to generate the three-component image model, and an example is provided in which the resulting three components demonstrate the specific properties as expected. Finally, it is shown that the primary component provides a superior representation of the strong edge information as compared with the popular Laplacian-Gaussian operator edge extraction scheme.