Kodak (Germany)

Abstract This contribution discusses photoinitiated crosslinking of multifunctional acrylic esters in polymeric binders based on digital imaging using the Computer to Plate (CtP) technology applying laser exposure at 830 nm in the near infrared (NIR). All coating components (NIR photoinitiator system, monomers, binder, adhesion promoter, contrast dye, and oxygen barrier material) were applied as thin double layer film (1–2 μm dry film thickness) on Al-plates with an anodized surface. Materials exposed exhibit a sensitivity between 30–200 mJ/cm2 depending on the NIR-photoinitiator composition. This was processed in a weak aqueous alkaline bath to obtain the image. Generation of initiating radicals occurs by electron transfer from the excited state of the NIR-sensitizer to the radical generator; that is either an onium salt or neutral electron deficient compound. Redox potentials were determined for the NIR-sensitizers and the radical generator. These data allow a rough estimate regarding the free energy of electron transfer of the excited state of the sensitizer and radical generator in NIR-photosensitive imaging material. Photoinduced electron transfer plays a major function to generate initiating radicals by a sensitized mechanism but thermal events also influence sensitivity of the coating. Particular the non-radiative deactivation of the NIR-sensitizer possesses a major function to release selectively the heat. Absorption data of many NIR-sensitizers used exhibit molar extinction coefficient of more than 200000 M –1 cm –1.

Distinct antler malformations, (such as lack of points, distortion of antler forms, incomplete velvet shedding, casting above the coronet and a diagonal separation of cast antlers), were detected in Sitka deer(Odocoileus hemionus sitkensis) of the Kodiak Island (Alaska, USA). Many of these deer were also unilateral or bilateral cryptorchids and a few exhibited a moderate or severe separation of frontal skull bones. Radioimmunoassay analyses of serum revealed signs of hypogonadism: we found higher concentrations of LH (P=0.05) and lower concentrations of T (P=0.037) in bilateral cryptorchids as compared to intact bucks. There was no apparent impairment of spermatogenesis in the remaining testis of the unilateral cryptorchid deer. Unfortunately, no ectopic testes were so far recovered in cryptorchid deer. Surprisingly, only about half of deer with bilateral cryptorchism exhibited hypogonadic symptoms. In the other half of cryptorchid deer, the antlers appeared completely normal and the concentrations of LH or testosterone in the serum of several bucks were in the range of intact deer. It has been postulated that in some cryptorchid deer, ectopic testes can produce sufficient amount of testosterone, which prevents obvious antler and skull malformations, as well as reduces the compensatory elevation of LH. The possible causes of the hypogonadism resulting in cryptorchism and antler malformations are discussed.