Hardware-assisted feature analysis and visualization of procedurally encoded multifield volumetric data

We take a new approach to interactive visualization and feature detection of large scalar, vector, and multifield computational fluid dynamics data sets that is also well suited for meshless CFD methods. Radial basis functions (RBFs) are used to procedurally encode both scattered and irregular gridded scalar data sets. The RBF encoding creates a complete, unified, functional representation of the scalar field throughout 3D space, independent of the underlying data topology, and eliminates the need for the original data grid during visualization. The capability of commodity PC graphics hardware to accelerate the reconstruction and rendering and to perform feature detection from this functional representation is a powerful tool for visualizing procedurally encoded volumes. Our RBF encoding and GPU-accelerated reconstruction, feature detection, and visualization tool provides a flexible system for visually exploring and analyzing large, structured, scattered, and unstructured scalar, vector, and multifield data sets at interactive rates on desktop PCs.     

e-R&D – Effectively Managing Process Diversity

Managing process diversity becomes increasingly relevant in software development. Software organizations typically do not work on the greenfield and thus need to integrate external workflows with R&;D internal workflow management and heterogeneous development and maintenance processes. To stay competitive with its software development, Alcatel has put in place an orchestrated improvement program of its processes and the underlying engineering tools environment. Why do we call this “e-R&;D”? For two reasons. These improvement activities necessarily fit into the wider context of Alcatel's business process improvement and corporate e-business initiatives. The “e-R&;D” also means enabling of interactive R&;D processes and increasing collaborative work across the globe. At Alcatel we realized, during a substantial reengineering of our development and industrialization processes, that the approach to acquire an off-the-shelf process and tailor it to our needs was not applicable. Different processes need to be seamlessly integrated to avoid inconsistencies and inefficiency caused by replicated work. Specific focus is given within this article on how we manage process diversity in a product line where various components are embedded in individual architectures, asking for different but defined development and maintenance processes depending on pre-selected criteria.     

Analysis of protein adsorption and binding at biosensor polymer interfaces using X-ray photon spectroscopy and scanning electrochemical microscopy

We describe a method, based on X-ray photoelectron spectroscopy (XPS) measurements, to assess the extent of protein adsorption or binding on a variety of different muTAS and biosensor interfaces. Underpinning this method is the labeling of protein molecules with either iodine- or bromine-containing motifs by using protocols previously developed for radiotracer studies. Using this method, we have examined the adsorption and binding properties of a variety of modified electrodeposited polymer interfaces as well as other materials used in muTAS device fabrication. Using polymer interfaces modified with poly(propylene glycol) (PPG) chains, our results indicate that a chain of at least approximately 30 monomer units is required to inhibit nonspecific adsorption from concentrated protein solutions. The XPS methodology was also used to probe specific binding of avidins and enzyme conjugates thereof to biotinylated and mixed biotin/PPG-modified polymer interfaces. In one example, using competitive binding, it was established that the mode of binding of a peroxidase-streptavidin conjugate to a biotinylated modified polymer interface was primarily via the streptavidin moiety (as opposed to nonspecific binding via the enzyme conjugate). XPS evaluation of nonspecific and specific peroxidase-streptavidin immobilization on various functionalized polymers has guided the design and fabrication of functionalized interdigitated electrodes in a biosensing muTAS device. Subsequent characterization of this device using scanning electrochemical microscopy (SECM) corroborated the adsorption and binding previously inferred from XPS measurements on macroscale electrodes.     

A homology model of penicillin acylase from Alcaligenes faecalis and in silico evaluation of its selectivity

A three-dimensional model of the relatively unknown penicillin acylase from Alcaligenes faecalis (PA-AF) was built up by means of homology modeling based on three different crystal structures of penicillin acylase from various sources. An in silico selectivity study was performed to compare this homology model to the structure of the Escherichia coli enzyme (PA-EC) in order to find any selectivity differences between the two enzymes. The program GRID was applied in combination with the principal component analysis technique to identify the regions of the active sites where the PAs potentially engage different interactions with ligands. These differences were further analyzed and confirmed by molecular docking simulations. The PA-AF homology model provided the structural basis for the explanation of the different enantioselectivities of the enzymes previously demonstrated experimentally and reported in the literature. Different substrate selectivities were also predicted for PA-AF compared to PA-EC. Since no crystallographic data are available for PA-AF to date, the three-dimensional homology model represents a useful and efficient tool for fully exploiting this attractive and efficient biocatalyst, particularly in enantioselective acylations of amines.     

Pharmacokinetics of Gadomer-17, a new dendritic magnetic resonance contrast agent

Rationale and objectives: Gadomer-17 is a new magnetic resonance (MR) contrast medium presently in clinical development. It is a dendritic gadolinium (Gd) chelate carrying 24 Gd ions. This study investigated the pharmacokinetic behavior of this contrast medium. Methods: The pharmacokinetics of Gadomer-17 were investigated in different species (rat, rabbit, dog, monkey) for up to 7 days after intravenous (i.v.) injection of 25–100 μmol/kg body weight. In addition, elimination and biodistribution were evaluated after single i.v. injection of Gadomer-17 in rats. Results: After i.v. injection Gadomer-17 distributes almost exclusively within the intravascular space without significant diffusion into the interstitial space. The volume of distribution (Vc) in the initial or α-phase ranged from 0.04 1/kg (rats, rabbits) to 0.06 1 kg (monkeys) and 0.07 1/kg (dogs), which reflects mainly the plasma volume. The blood/plasma concentration profile was found to be biphasic. The volume of distribution at a steady state is clearly smaller than that of other contrast media, which distribute to the extracellular space. After single i.v. injection in rats, the dendritic contrast medium was rapidly and completely eliminated from the body, mainly via glomerular filtration. No long-term accumulation or retention of the nonmetabolized agent was detectable in organs or tissues. Conclusions: Gadomer-17 is a promising new MR contrast medium that has an intravascular distribution and a rapid renal elimination.     

Psychological assessment of candidates for solid organ transplantation.

The role of psychologists, who can assist in preparing clients for transplant surgery and support them postsurgery to sustain the complex maintenance protocol, is outlined. An overview of specific procedures used in the psychological evaluation and treatment of solid organ transplant patients, a discussion of general issues involved in treating these patients, and case vignettes are provided. As transplants become more common, the need for additional psychologists as part of multidisciplinary treatment teams increases. Because many patients live great distances from the transplant center, community psychologists may be enlisted to treat organ transplant patients and to collaborate with psychologists on transplant teams. (PsycINFO Database Record (c) 2010 APA, all rights reserved)