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Figure 1: Boundary element rendering of biharmonic diffusion curve images. From left to right: toys image; sharp-profile (solid) and smooth-profile (dotted) curves of the toys image, with thumbnail images below showing examples of the 4 building block segment fields; car image and pumpkin image. The above images are c CiSRA; the toys image is a CiSRA re-creation of a photograph taken by C. Concolato. AbstractThere is currently significant interest in freeform, curve-based authoring of graphic images. In particular, "diffusion curves" facilitate graphic image creation by allowing an image designer to specify naturalistic images by drawing curves and setting colour values along either side of those curves. Recently, extensions to diffusion curves based on the biharmonic equation have been proposed which provide smooth interpolation through specified colour values and allow image designers to specify colour gradient constraints at curves. We present a Boundary Element Method (BEM) for rendering diffusion curve images with smooth interpolation and gradient constraints, which generates a solved boundary element image representation. The diffusion curve image can be evaluated from the solved representation using a novel and efficient line-by-line approach. We also describe "curve-aware" upsampling, in which a full resolution diffusion curve image can be upsampled from a lower resolution image using formula evaluated corrections near curves. The BEM solved image representation is compact. It therefore offers advantages in scenarios where solved image representations are transmitted to devices for rendering and where PDE solving at the device is undesirable due to time or processing constraints.

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The effects of radiation upon circulating lymphocytes have been measured by two independent means, one monitoring the level of cytogenetic damage appearing in these cells, the other monitoring changes in their proliferative response to stimulation in culture by phytohaemagglutin (PHA). Response to PHA can be expressed quantitatively as lymphocyte replicating ability (LRA), i.e. the degree of 3 H-thymidine uptake measured under standardized conditions. Varying degrees of depression of LRA have been noted within a group of patients undergoing a wide range of radiotherapeutic procedures. The concomitant cytogenetic studies indicate that although cells bearing radiation damage do persist in the circulation after irradiation their numbers are insufficient to account for the marked reduction seen at the same time in LRA. It appears that the reduction is largely due to a fall in the number of thymusdependent lymphocytes in the circulatory pool.

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