Implementation of visualization tools in a distributed environment

Maurotoxin (MTX) and HsTx1 are two scorpion toxins belonging to the alpha-KTx6 structural family. These 34-residue toxins, cross-linked by four disulfide bridges, share 59% sequence identity and fold along the classical alpha/beta scaffold. Despite these structural similarities, they fully differ in their pharmacological profiles. MTX is highly active on small (SK) and intermediate (IK) conductance Ca(2+)-activated (K(+)) channels and on voltage-gated Kv1.2 channel, whereas HsTx1 potently blocks voltage-gated Kv1.1 and Kv1.3 channels only. Here, we designed and chemically produced MTX-HsTx1, a chimera of both toxins that contains the N-terminal helical region of MTX (sequence 1-16) and the C-terminal beta-sheet region of HsTx1 (sequence 17-34). The three-dimensional structure of the peptide in solution was solved by (1)H NMR. MTX-HsTx1 displays the activity of MTX on SK channel, whereas it exhibits the pharmacological profile of HsTx1 on Kv1.1, Kv1.2, Kv1.3, and IK channels. These data demonstrate that the helical region of MTX exerts a key role in SK channel recognition, whereas the beta-sheet region of HsTx1 is crucial for activity on all other channel types tested.

Introduction In order to sustain the current production capacity of crude oil in Western Ganada, enhanced oil recovery (EOR) techniques such as utilizing carbon dioxide (CO2) must be used. According to Saskatchewan Department of Energy and Mines, a large amount of crude oil worth multi-billion of dollars can be recovered using these techniques. At, the same time, a large amount of carbon dioxide (CO2) is, being produced by industrial plants in the region. This, tremendous quantity of carbon dioxide is discharged into the atmosphere and could be causing an enhanced greenhouse effect nd global warming. To overcome the CO2 emission problem, here is great interest to capture the carbon dioxide and utilize it as a flooding agent for EOR processes. The concept of recovering O2 and utilizing it as an EOR flooding agent or chemical feedstock will provide two important benefits. First, we can market the captured O2 as a commodity chemical which would generate revenue. Second, we will be able to reduce CO2 emissions to the atmosphere and help alleviate a serious environmental problem, at minimum cost. The ultimate goal of this research and development program is to develop better and more effective CO2 separation processes which can be used to recover CO2 from industrial sources such as fossil fuel fired power stations, coal gasification plants and hydrogen production units for EOR applications at the lowest possible apital and operating costs. Research Facilities and Personnel We have initiated a research program on high efficiency separation process technologies for carbon dioxide removal from industrial sources at the Process Systems Laboratory, University of Regina since 1991. We have acquired and built a number of pieces of research apparatus, equipment and pilot plants over the past five years. These include three pilot plant units for testing high efficiency gas treating systems which consists of different sizes of absorption and regeneration towers packed with a variety of high performance packings. The pilot plants are also equipped with microprocessor-based infrared gas analysers, state-of-the-art gas chromatograph units and a high speed digital data logging system. We are in the process of acquiring an ion chromatographysystem and a GC/MS mass detector for comprehensive analysis of solvent compositions and their activities. In addition, a number of embrane reactors have been constructed which can be used as very high capacity absorbers, as well numerous pieces of research apparatus have been built for solvent absorption capacity testing, corrosion studies and gas/liquid diffusivity determination. In terms of computer applications, our laboratory now is well equipped with and has access to high performance computing facilities. including three high speed Pentium work-stations (each has 64 MB memory and 2.5 GB Hard Drive), a number of 486 PCs, a Silicon Graphics work station (32 MB memory. 1 GB Hard ive) and a very large Silicon Graphics Server (12 of 150 Mhz processor, 1 GB memory, 22 GB Hard Drive). These computing facilities are also equipped with state-of-the-art real time intelligent systems development tools such as G2, GDA, NeurOn-Line, COMDALEIX and COMDALE/C, as well as advanced computeraided process engineering simulators including ASPEN.

: As outlined in the original proposal, FEO intends to determine how effectively a neural network coupled to a multiple aperture vision system (MAVS) can be applied to the tracking task. Over the course of the contract FEO will perform seven (7) experimental simulations to evaluate the proposed tracking systems' performance. The October 15, 1992 report discussed the modeling of the first three (3) configurations. The following report discusses the results of the implementation of these first three experiments on the Silicon Graphics IRIS Indigo workstation. Additionally, FEO has completed the optical modeling of experiments four through seven and completed the C++ coding of experiments four and five. FEO has enclosed a DAT tape containing executable code and source code for experiments 1 through 3. The programs can be loaded onto a Silicon Graphics workstation using the tar tape facility. A description of the operation of each program is provided below. Once begun, operation of the executable programs is self-explanatory.

Huwentoxin-X (HWTX-X) is a novel peptide toxin, purified from the venom of the spider Ornithoctonus huwena. It comprises 28 amino acid residues including six cysteine residues as disulfide bridges linked in the pattern of I-IV, II-V, and III-VI. Its cDNA, determined by rapid amplification of 3' and 5' cDNA ends, encodes a 65-residue prepropeptide. HWTX-X shares low sequence homology with omega-conotoxins GVIA and MVIIA, two well known blockers of N-type Ca2+ channels. Nevertheless, whole cell studies indicate that it can block N-type Ca2+ channels in rat dorsal root ganglion cells (IC50 40 nm) and the blockage by HWTX-X is completely reversible. The rank order of specificity for N-type Ca2+ channels is GVIA approximately HWTX-X > MVIIA. In contrast to GVIA and MVIIA, HWTX-X had no detectable effect on the twitch response of rat vas deferens to low frequency electrical stimulation, indicating that HWTX-X has different selectivity for isoforms of N-type Ca2+ channels, compared with GVIA or MVIIA. A comparison of the structures of HWTX-X and GVIA reveals that they not only adopt a common structural motif (inhibitor cystine knot), but also have a similar functional motif, a binding surface formed by the critical residue Tyr, and several basic residues. However, the dissimilarities of their binding surfaces provide some insights into their different selectivities for isoforms of N-type Ca2+ channels.

Confocal Laser Scanning Microscopy and 3-D Reconstructions of Neuronal Structures in Human Brain Cortex

We developed the virtual cockpit as an inexpensive flight simulator, using off-the-shelf equipment. This system functions as a component of a distributed interactive simulation. Any flight simulator has three principal tasks: image display, image generation, and flight dynamics. We built the flight simulator, the virtual cockpit, using a head-mounted display (HMD) to display the out-the-window imagery and the cockpit interior. The virtual cockpit consists of a Silicon Graphics workstation and supporting hardware components, such as an HMD and position tracker. The software falls into three areas by function: flight dynamics and cockpit instruments; network interface (either SimNet or DIS PDUs); and display of the out-the-window view. The virtual cockpit developed uses a multiprocessor Silicon Graphics Iris (the 4D/440VGXT) connected to a Polhemus Laboratories fiber-optic head-mounted display, a Polhemus magnetic head tracker and a hands-on-throttle-and-stick (HOTAS) by Thrustmaster. The software uses the AT and T C++ translator and the Silicon Graphics C compiler running under Irix 4.0.5. a Unix operating system. We use Software Systems' MultiGen to create the geometric models and the terrain database.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Direct numerical simulations of quartz particles, given a turbulent stationary velocity field, are per formed in "real time" on a Silicon Graphics work station. Interaction of the surrounding flozu on spherical particles is taken into account by a modi fied version of the Basset-Boussinesq-Oseen equa tion, including nonlinear resistance. Boundary con ditions (walls) are modeled with the use of reflection laws. Interactions between particles are neglected. The velocity field has been pre-computed with the k—∈ model over different geometries. Second-order accuracy numerical implementation and error esti mation are discussed. Impacts on s urfaces are ac counted for by means of direction and kinetic energy of incident particles. The areas with the highest probability of damage are then mapped. Real-time high-quality interactive graphics are an important aspect of this useful numerical tool.

An examination is made of three projects underway at LLNL. The Magic (Machine Graphics in Color) Project is developing techniques to move data from a Cray supercomputer and effectively display it on high-resolution color terminal in the scientist's office. In a follow-on to this project, laser disk technology provides a real-time animation capability. The Graphics Workstation Project has examined visualization applications of workstations with graphics accelerators and is currently extending this work to 'graphics minisupercomputers'. The Advanced Visualization Research Project uses high-end graphics devices to perform algorithm development, especially in the implementation of volumetric methods.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Several display techniques were compared for representing scientific data in the context of a feature detection task. The data sets were rendered on a Silicon Graphics workstation using four display formats: linearized gray scale; rainbow scale; reduced hue (blue-green-yellow-white) scale; and a 3D-topographic format viewed in stereo. The task involved searching for features that were embedded in scientific data sets consisting of two spatial and one scalar variable. Data sets were drawn from three scientific domains: Landsat, medical MRI, and global atmospheric data bases. Two types of features were embedded within the data sets: circular (blob-like) discontinuities, and linear (cliff-like) discontinuities. Results showed a general advantage for the gray scale, and a marked disadvantage for the 3D-topographic format in both accuracy and response latency. Performance in the two color scale formats was intermediate, with the reduced hue scale supporting faster, if not more accurate performance than the full rainbow scale. Performance differences were found across data base domains, as well. Directions for future research are discussed.

Techniques are now available to move uncompressed digital video data faster than realtime in packetized network environments. Using ANSI standard Fibre Channel serial interfaces on Silicon Graphics workstations and servers, computer-to-computer and computer-to-disk communications have been demonstrated to transfer digital image data at a sustained throughput up to 600 megabits/sec. With these interfaces, production, post-production and broadcast facilities are achieving order-of-magnitude improvements in response time when accessing and transferring large files.

Economical methods are now available to move uncompressed digital video faster than real time in networked environments. Using an ANSI standard Fibre Channel interface on a Silicon Graphics workstation with optimized hardware and software, both computer-to-computer and computer-to-disk communications are possible which can transfer data at rates up to 640 megabits/second. By incorporating these interfaces, post-production facilities can achieve order-of-magnitude improvements when accessing and transferring large video files, and can gain the ability to move streams of digital video data faster than real time for collaborative creative efforts. Video server applications can use these interfaces for both storage access and communications for transporting up to 100 compressed streams simultaneously through a single port.

A robotic simulation and off-line programming package has been developed for use on Silicon Graphics workstations that has the capability of using several types commercially available virtual reality (VR) hardware devices. The software includes a library of 4, 5, and 6 degree-of-freedom (DOF) industrial robots with closed form inverse kinematics and translators that convert graphical simulation commands into the device control language that can be transferred to the robot control hardware. Forward kinematics, inverse kinematics, and joint space path planning methods used in the software development are discussed. The performance of three types of commercially available 6-DOF input devices are compared for use in interactive off-line programming. Stereo vision and external 6-DOF positioning devices were added to enhance programming efficiency and offer more realistic access to the virtual workcell environment.

Electropalatography (EPG) is a useful tool for investigating tongue dynamics in experimental phonetic research and speech therapy. However, data provided by EPG are a two-dimensional representation in which all absolute positional information is lost. This paper presents an enhanced EPG (eEPG) system which uses digitised palate shape data to display the tongue-palate contact pattern in three dimensions. The palate shapes are obtained using a colour-encoded structured light three-dimensional digitisation system. The three-dimensional palate shape is displayed on a Silicon Graphics workstation as a surface made up of polygons represented by a quadrilateral mesh. EPG contact patterns are superimposed on to the three-dimensional palate shape by displaying the relevant polygons in a different colour. By using this system, differences in shape between individual palates, apparent on visual inspection of the actual palates, are also apparent in the image on screen. Further, methods have been devised for computing absolute distances along paths lying on the palate surface. Combining this with calibrated palate shape data allows accurate measurements to be made between contact locations on the palate. These have been validated with manual measurements. In addition, vocal tract areas in the oral cavity have been estimated by using the absolute measurements on the palate for a given contact pattern, and assuming a flat tongue profile in the uncontacted area.

MD display: An interactive graphics program for visualization of molecular dynamics trajectories

Presents the latest results of a research activity oriented to the development of a multimedia telephone for hard of hearing persons, based on the conversion of speech into graphic animation suitable to lipreading. The approach followed aims at the experimentation of a pilot telematic service for interpersonal communication, thus enlarging and improving the possibilities of social integration for hearing-impaired people. A preliminary prototype of the multimedia telephone has been integrated in a software demonstrator implemented on a Silicon Graphics workstation and is currently experimented in cooperation with FIADDA, the Italian Association of the parents of hearing-impaired children, to prove the feasibility of the system and the concrete possibility of providing new relay mediation services oriented to multimedia interpersonal communication for hard of hearing users. The developed algorithms rely on advanced methodologies in the field of nonlinear signal processing through neural network architectures, geometric modeling, computer graphics, and animation. Experimental results, although still preliminary, are encouraging and prove the system's feasibility. >