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Grafting of poly(acrylic acid) onto commercial polypropylene films following irradiation by γ-rays was carried out in order to improve their surface properties. The amount of grafting with the irradiation dose was found not to follow the expected linear dependence as it is normally observed for polypropylene films prepared in laboratory amounts. We therefore analyzed the influence of the industrial manufacture process in terms of orientation of the film and addition of antioxidants by determining the peroxide surface density and the extent of grafting therefrom. The unoriented polypropylene film presented the highest peroxide concentration and was thus the most adapated material for successful grafting. Whereas phenol antioxidants limit the peroxide formation and thus must be removed from the film for grafting, the thickness of the chemical modification and can be controlled by means of phosphites. Atomicforce microscopy and wettability measurements showed that the grafted poly(acrylic acid) was heterogeneously distributed on the surface of the film, explaining the observed low reproducibility of the grafting reaction. However, we observed that the polarity of the surface was increased by the grafting. © 1995 John Wiley & Sons, Inc.

With the widespread use of laparoscopic cholecystectomy (LC), the role of pre- and postoperative endoscopic retrograde cholangiopancreatography (ERCP) and / or endoscopic sphincterotomy (ES) has become very important. Indications for ERCP with possible ES before LC include clinical suspicion of a common bile duct (CBD) stone alone, evidence of jaundice, recent cholangitis or pancreatitis that is probably due to a duct stone or dilated CBD. Local endoscopic and surgical expertise are important factors in deciding the approach to the pre-LC patients. The success rate of ductal clearance of stones by ES approaches 90 to 95% in expert hands. ERCP is very effective in the management of post-LC patients with symptoms, as well as in diagnosing and treating complications such as retained stones, ductal leaks and strictures.

To gain some knowledge on the influence of a substrate morphology upon radiochemical grafting efficiency, the formation and the evolution of irradiation induced peroxy-radicals were measured by ESR in two polypropylene (PP) films of different origins. The creation rate of peroxy-radicals was found to be almost proportional to the irradiation dose in the film presenting the best crystallinity, the bi-oriented PP, while it saturates in the unoriented one. The recombination kinetics of the radicals appeared to be controlled by their diffusion in the matrix and the corresponding diffusion coefficients are dependent on the matrix itself and on its evolution under irradiation. It is suggested that the crystalline order of the matrix is the parameter governing the mobility and thus the lifetime of the radicals. © 1994 John Wiley & Sons, Inc.

Stress-induced mucosal ulcerations are associated with a decreased synthesis of mucosal prostaglandin (PG) E2. This phenomenon is poorly understood. To investigate whether it is due to a decreased availability of the necessary substrates to the mucosa, four groups of 10 Holtzman rats were studied: group 1 received normal saline by intraperitoneal (ip) injection; group 2 also received ip normal saline, then were submitted to stress, by the cold restraint method; group 3 received a solution of arachidonic acid (AA) ip; and group 4 also received ip AA, then were submitted to stress. After sacrifice, the number of gastric ulcerations were counted and specimens of nonulcerated mucosa were assayed for PGE2 by high-performance liquid chromatography; the mean numbers of ulcers were 0, 5.8, 0.8, and 3 and the mean levels of PGE2 were 55, 41, 125, and 62 pg/mg of wet tissue for groups 1, 2, 3, and 4, respectively. It is concluded that parenteral administration of AA reduces but does not completely eliminate stress-induced gastric ulcerations and that the stressed animals synthesized half as much PGE2 as the nonstressed ones after ip administration of equal amounts of AA, suggesting that stress reduces the availability of AA to the gastric mucosa, possibly by vascular spasm.

— Nowadays, low-contrast viewing of LC displays (LCDs) occurs very often, which includes the viewing of mobile LCDs at high ambient illumination and the viewing of LCDs at low-power mode. These cases result in low-content visibility and low contrast, leading to an unpleasant viewing experience. In this paper, a technique to improve the perceived contrast and visibility of images at low-contrast viewing conditions is proposed. The proposed approach enhances image brightness with content and ambient adaptive image brightening and highlights visual parts and boundaries with non-photorealistic rendering. The proposed technique enables longer battery life for mobile LC devices and makes mobile LC devices viewable at high ambient illumination. It also enables TVs with extreme low-power consumption and smart-grid responsive TVs.

We discuss an algorithm that works with the concept of a reserved highlight region. It primarily addresses the problem of displaying legacy images calibrated for StandardDynamic Range displays onto displays having higher dynamic range, such as Megacontrast displays having standard brightness and bitdepth, as well as HighDynamic Range displays having increased brightness and bitdepth. The technique reserves headroom of the display range past maximum diffuse white for specular highlights and selfluminous objects. The paper discusses how to detect the specular highlights and light sources, how to construct a tonescale with reserved headroom, and different experiments conducted to learn how much of the dynamic range should be allocated for this upper luminance.

In this paper, we extend the work on increasing energy efficiency of a TV to algorithms enabling extreme power reduction. Tools to maintain display performance at limited power are described. These tools can be intelligently managed to enable Demand Response functionality with a Smart Grid connected TV.

Backlight dimming is the predominant method for power reduction in LDC displays and image processing can compensate for such dimming. We propose a low complexity approach which replaces hard clipping with smooth roll-off. A high quality approach preserves highlight detail. Image quality is improved and power savings can be increases by more aggressive BL dimming capable with these methods.

— Backlight dimming is a dominant method for power reduction in LCDs. Image processing with a simple boost and clip can compensate for such dimming-restoring image brightness. We propose a low complexity approach which replaces hard clipping with smooth roll-off to reduce clipping artifacts. An additional high-quality approach uses a two-channel spatial-frequency decomposition to preserve highlight detail attenuated by the roll-off. Image quality is improved and power savings can be increased by more-aggressive backlight dimming.

The resolution of colour matrix displays can be increased by rendering images using subpixel rendering, but at the cost of colour aliasing if appropriate filtering is not done. The problem has been effectively solved for the case of one-dimensional RGB striped matrix displays by using chrominance post-filters based on a human perceptual model. In this paper we extend this result and present a general framework for rendering on 2D subpixel geometries.