A Biologically-Parameterized Feather Model

Feathers, unlike other cutaneous appendages such as hair, fur, or scales have a definite structure. Variation in feather structure creates a wide range of resulting appearances. Collectively, feather structure determines the appearance of the feather coat, which can largely affect the resulting look of a feathered object (bird). In this paper we define the structure of individual feathers using a parameterization based on biological structure and substructures of actual feathers. We show that our parameterization can generate a large variety of feathers at multiple levels of detail and provide an initial step to semi‐automatically generating a wide range of feather coats. his is achieved by specifying an intuitive interpolation between different structures and ages of feathers.     

Fabrication of a heterodyne receiver OEIC with optimized integration process using three MOVPE growth steps only

An optimized integration process is reported requiring only three epitaxial growth steps for the fabrication of an OEIC encompassing a single-mode laser, a waveguide element, and fast photodiodes. The process was applied to the fabrication of a heterodyne receiver including a semi-insulating buried heterostructure (SIBH)-DFB-laser with an output power of 14 mW and a side-mode suppression ratio greater than 40 dB, a 3-dB coupler, and high-speed balanced photodiodes with a bandwidth of 9 GHz. The laser can also be used as a transmitter laser exhibiting a modulation bandwidth of 11 GHz.     

Polarisation transformer on Ti:LiNbO3 with reset-free optical operation for heterodyne/homodyne receivers

Experimental results for an integrated-optical state-of-polarisation (SOP) controller device on Ti:LiNbO3 for continuous broadband optical operation, with small temperature sensitivity and the possibility of integration with polarisation- insensitive directional couplers, are presented.     

Volume-Surface Trees

Many algorithms in computer graphics improve their efficiency by using Hierarchical Space Subdivision Schemes (HS³), such as octrees, kD‐trees or BSP trees. Such HS³ usually provide an axis‐aligned subdivision of the 3D space embedding a scene or an object. However, the purely volume‐based behavior of these schemes often leads to strongly imbalanced surface clustering. In this article, we introduce the VS‐Tree, an alternative HS³ providing efficient and accurate surface‐based hierarchical clustering via a combination of a global 3D decomposition at coarse subdivision levels, and a local 2D decomposition at fine levels near the surface. First, we show how to efficiently construct VS‐Trees over meshes and point‐based surfaces, and analyze the improvement it offers for cluster‐based surface simplification methods. Then we propose a new surface reconstruction algorithm based on the volume‐surface classification of the VS‐Tree. This new algorithm is faster than state‐of‐the‐art reconstruction methods and provides a final semi‐regular mesh comparable to the output of remeshing algorithms.     

Continuous analysis in extracorporeally circulating blood--a rat model applying flow-through ion-selective electrodes for the measurement of Ca2+, K+, Na+ and pH

A rat model is introduced which enables investigations in anticoagulated blood with continuous measurements by a flow-through electrode system. In the present study, a potentiometric ion-selective electrode (ISE)-system was used for measuring Ca2+, K+, Na+ and pH in rats. The setup was adjusted to an extracorporeal blood-volume of 0.750 ml. This permits indirect measurements of the analytes via a dialysis membrane, with electrical separation of the ISE's and the animal. The flow-rates of blood and dialysis-solution were adjusted in such a way that water diffusing from the aqueous dialysis solution into the blood, across the dialysis membrane, does not alter the haematocrit. Polyethyleneglycol-hirudin was used for anticoagulation, since it was superior to heparin. The assembly enables continuous measurements in the living anaesthetized rat over a time period of at least 3 hours.     

Interactive Display of Global Illumination Solutions for Non-diffuse Environments – A Survey

In recent years there has been a lot of work on interactively displaying global illumination solutions for non-diffuse environments. This is an extremely active field of research, in which a lot of different approaches have recently been proposed. In this survey, we will discuss and compare these. This will hopefully prepare the ground for systematically addressing the open questions in the future.     

Hexokinase 2 from Saccharomyces cerevisiae: regulation of oligomeric structure by in vivo phosphorylation at serine-14

Homodimeric hexokinase 2 from Saccharomyces cerevisiae is known to have two sites of phosphorylation: for serine-14 the modification in vivo increases with glucose exhaustion [Kriegel et al. (1994) Biochemistry 33, 148-152], while for serine-157 it occurs in vitro with ATP in the presence of nonphosphorylateable five-carbon analogues of glucose [Heidrich et al. (1997) Biochemistry 36, 1960-1964]. We show now by site-directed mutagenesis and sedimentation analysis that serine-14 phosphorylation affects the oligomeric state of hexokinase, its substitution by glutamate causing complete dissociation; glutamate exchange for serine-157 does not. Phosphorylation of wild-type hexokinase at serine-14 likewise causes dissociation in vitro. In view of the higher glucose affinity of monomeric hexokinase and the high hexokinase concentration in yeast [Womack, F., and Colowick, S. P. (1978) Arch. Biochem. Biophys. 191, 742-747; Mayes, E. L., Hoggett, J. G., and Kellett, G. L. (1983) Eur. J. Biochem. 133, 127-134], we speculate that the in vivo phosphorylation at serine-14 as transiently occurring in glucose derepression might provide a mechanism to improve glucose utilization from low level and/or that nuclear localization of the monomer might be involved in the signal transduction whereby glucose causes catabolite repression.     

Thin-film acousto-optic interaction in LiNbO3

100% Bragg diffraction of guided optical waves by surface acoustic waves in metal-diffused layers in LiNbO3 substrates has been observed. The predicted efficiency, which compares favourably with experimental measurement, is shown to arise mainly from the electro-optic contribution of the electric field associated with the yz acoustic surface waves instead of the clasto-optic contribution due to the strain or from the surface ripple components.     

Decrease of disaccharidase activity following application of bencyclan-hydrogenfumarate (author's transl)

The disaccharidase activity of the small bowel mucosa of the rat is decreased by intraperitoneal application of Bencyclan-hydrogenfumarate. The doses applied were 10, 50 and 100 mg/kg body weight. The decrease rate after 100 mg/kg attained up to 50% of the control values. Furthermore, a reduction of villous height and an increase of the crypt depth has been observed in correlation with the enzyme activity decrease. Though functional and morphological alterations show a correlation, they cannot be explained by an antimetabolic-like effect because of the fact that the enzyme function recovers 72 h after application of the drug. Whilst our results do not sustain a cytostatic effect of Bencyclan-hydrogenfumarate, there is no doubt that the intraperitoneally applied drug influences the disaccharidase activity. These facts have to be considered in clinical therapy.