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At least 325 records · Page 18Linked to original sources
PubMed2004

Brain-computer interface design for asynchronous control applications: improvements to the LF-ASD asynchronous brain switch.

The low-frequency asynchronous switch design (LF-ASD) was introduced as a direct brain-computer interface (BCI) technology for asynchronous control applications. The LF-ASD operates as an asynchronous brain switch (ABS) which is activated only when a user intends control and maintains an inactive state output when the user is not meaning to control the device (i.e., they may be idle, thinking about a problem, or performing some other action). Results from LF-ASD evaluations have shown promise, although the reported error rates are too high for most practical applications. This paper presents the evaluation of four new LF-ASD designs with data collected from individuals with high-level spinal cord injuries and able-bodied subjects. These new designs incorporated electroencephalographic energy normalization and feature space dimensionality reduction. The error characteristics of the new ABS designs were significantly better than the LF-ASD design with true positive rate increases of approximately 33% for false positive rates in the range of 1%-2%. The results demonstrate that the dimensionality of the LF-ASD feature space can be reduced without performance degradation. The results also confirm previous findings that spinal cord-injured subjects can operate ABS designs to the same ability as able-bodied subjects.

Adult↗
PubMed1974

Computer program designed to follow fluctuations in microbial populations and its application in a study of Chesapeake Bay microflora.

A computer program has been developed which performs cluster analysis of microorganisms using methods of numerical taxonomy. The program is designed to group related strains, identify the groups by reference to known strains, and calculate a hypothetical median organism (HMO) for each group. The HMO serves to condense taxonomic information and provides a tag for each strain cluster. Every strain in a group is compared with the HMO established for that group. A representative strain for the group is obtained by selection of the strain showing highest similarity to the HMO. New data sets can be compared with data sets of previous analyses. Hence, the occurrence of the same taxonomic groups within separate data sets can be determined. Quantitative or qualitative differences in distribution of taxonomic groups within or between data sets can be measured. The output from the computer is a graphical display, using an on-line plotter; thus, the investigator is provided with visual comparison of data sets. Results obtained from a study applying the computer program in an analysis of taxonomic data obtained for 43 bacterial strains isolated from Chesapeake Bay indicate the usefulness of this method of taxonomic analysis in microbial ecology.

Bacteria↗
PubMed1995

[Computer-assisted design and manufacture of an orbital cavity prototype].

Based on the results obtained in two dimensions or extrapolated into three dimensions by current medical imaging techniques (CT scan, magnetic resonance imaging), it is possible, under certain conditions, to create hard complex anatomical specimens, of obvious value in cold surgery. Two successive approaches of design and manufacture of an orbital cavity prototype are presented, as a preliminary to industrial productions soon to be released onto the market.

Biomechanical Phenomena↗
PubMed1998

Computer-assisted design of new drugs based on retrometabolic concepts.

Retrometabolic drug design approaches incorporate metabolic and toxicological considerations into the drug design process and represent a novel, systematic methodology for the design of safe compounds. Two major design concepts aimed to increase the therapeutic index (the activity/toxicity ratio) of drugs were developed. Chemical delivery systems (CDS) are primarily used to allow targeting of the active biological molecules to specific target sites or organs based on predictable enzymatic activation. Soft drug approaches are used to design new drugs by building in the molecule, in addition to the activity, the most desired way in which the molecule is to be deactivated and detoxified subsequent to exerting its biological effects. Special computer programs were developed that starting from a lead compound generate complete libraries of possible soft analogs and then help ranking these candidates based on isosteric-isoelectronic comparisons, predicted solubility/partition properties, and estimated metabolic rates. The novel field of large peptide-CDSs imposes special challenges, but a new, remarkably simple model was developed to estimate partition properties for a wide range of compounds, including quite large peptide derivatives. A suggested change of about five order of magnitudes in the distribution coefficient can explain the "lock in" mechanism of brain-targeting delivery systems.

Animals↗
PubMed2004

Scaffold-based tissue engineering: rationale for computer-aided design and solid free-form fabrication systems.

One of the milestones in tissue engineering has been the development of 3D scaffolds that guide cells to form functional tissue. Recently, mouldless manufacturing techniques, known as solid free-form fabrication (SFF), or rapid prototyping, have been successfully used to fabricate complex scaffolds. Similarly, to achieve simultaneous addition of cells during the scaffold fabrication, novel robotic assembly and automated 3D cell encapsulation techniques are being developed. As a result of these technologies, tissue-engineered constructs can be prepared that contain a controlled spatial distribution of cells and growth factors, as well as engineered gradients of scaffold materials with a predicted microstructure. Here, we review the application, advancement and future directions of SFF techniques in the design and creation of scaffolds for use in clinically driven tissue engineering.

Biocompatible Materials↗
PubMed1985

Advanced prosthetic techniques for below knee amputations.

Recent advances in the evaluation of the amputation stump, the materials that are available for prosthetic application, techniques of improving socket fit, and prosthetic finishings promise to dramatically improve amputee function. Precision casting techniques for providing optimal fit of the amputation stump using materials such as alginate are described. The advantages of transparent check sockets for fitting the complicated amputation stump are described. Advances in research that promise to provide more functional prosthetic feet and faster and more reliable socket molding are the use of CAD-CAM (computer aided design-computer aided manufacturing) and the use of gait analysis techniques to aid in the alignment of the prosthesis after socket fitting. Finishing techniques to provide a more natural appearing prosthesis are described. These advances will gradually spread to the entire prosthetic profession.

Amputation, Surgical↗
PubMed1987

HERSIM: a microcomputer program designed to compute the limits of conversion for real homogeneous isothermal enzymic reactors.

HERSIM is a program written in BASIC designed to aid the investigator interested in determining the substrate conversion in a real homogeneous isothermal enzymic reactor, for various kinetic equations. The program runs after tracer data relative to a Dirac impulse to the reactor have been entered, and computes the two limits of real conversion: total segregation and maximum mixedness. The kinetic constants of the reacting system are input as data, and the variation of conversion with reactor temperature between given limits is computed as accurately as requested.

Algorithms↗
PubMed1995

Update on computer-aided drug design.

Recent advances in computational methods for drug design include developments in quantitative structure-activity relationship approaches as well as novel structure-based strategies. Many new protein structures of pharmaceutical interest have been solved, a number of which contain a bound inhibitor. Continued progress has been reported in algorithms for de novo design, ligand docking, and scoring of protein-ligand binding energy. Meanwhile, several drugs that were designed by intensive use of computational methods are advancing through clinical trials.

Biotechnology↗
PubMed2006

Simulating molecular shuttle movements: towards computer-aided design of nanoscale transport systems.

Molecular shuttles based on the motor protein kinesin and microtubule filaments have the potential to extend the lab-on-a-chip paradigm to nanofluidics by enabling the active, directed and selective transport of molecules and nanoparticles. Based on experimentally determined parameters, in particular the trajectory persistence length of a microtubule gliding on surface-adhered kinesin motors, we developed a Monte-Carlo simulation, which models the transport properties of guiding structures, such as channels, rectifiers and concentrators, and reproduces the properties of several experimentally realized systems. Our tool facilitates the rational design of individual guiding structures as well as whole networks, and can be adapted to the simulation of other nanoscale transport systems.

Computer Simulation↗
PubMed1991

A low cost computer aided design (CAD) system for 3D-reconstruction from serial sections.

This paper describes an approach to computer-assisted 3D-reconstruction of neuronal specimens based on a low cost yet powerful software package for a personal computer (Atari ST). It provides an easy to handle (mouse driven) object editor to create 3D models of medium complexity (15,000 vertices) from sections or from scratch. The models may be displayed in various modes including stereo viewing and complex animation sequences.

Animals↗