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At least 1,117 records · Page 62Linked to original sources
PubMedDate not supplied

Computerized blood pressure and heart rate recording system interfaces standard chart recorder with any micro-computer.

The designed inexpensive blood pressure recording system (BPRS) gives any microcomputer direct on-line blood pressure and heart rate recording capability that will save research time and increase the accuracy of collected data. The data is automatically stored in a file compatible with most graphic and statistical processing software. In vitro testing, over a range of 0-200 mmHg and 0-360 beats per minute showed a 0.999 intraclass correlation. In vivo testing of the BPRS used anaesthetized rats whereby their systolic and diastolic pressures were measured simultaneously with heart rate. The blood pressures and heart rate data, measured by the BPRS demonstrated excellent stability, sensitivity and accuracy when compared to those measured by standard pressure transducers in conjunction with a Grass polygraph and a sphygmomanometer.

Animals↗
PubMedDate not supplied

Interface design and cognitive style in learning an instructional computer simulation.

An experimental design was used to investigate how cognitive style interacts with interface design to affect users' abilities to learn to use a computer simulation. Eighteen nursing students were assigned to two groups, based on their cognitive style, and asked to solve 3 physiologic problems using 3 interface designs: a strip-chart display, an integrated balloon display, and an etiologic display. Students were given up to 2 minutes to solve each problem by administering 6 different hypothetical drugs targeted at different aspects of the simulated hemodynamic system. A mixed-design analysis of variance was used to determine the effects of interface design and cognitive style on number of problems solved, time to initiate treatment, percentage of time system maintained within normal parameters, and number of drugs used. We found that the effects of cognitive style on performance were mediated by interface design and tended to decrease with practice.

Analysis of Variance↗
PubMed1997

Individual prostheses and resection templates for mandibular resection and reconstruction.

This new technique uses helical computed tomography data and computer-aided design and manufacturing for preoperative fabrication of individual mandibular prostheses together with corresponding resection templates. Coherent 3D geometries for computer-based models are the basis for the construction of prostheses and provide data for a computerized numerical control fabrication. Fixation plates are fabricated with the titanium prostheses. The identical data of these plates are used for the computer-aided design and manufacturing of resection templates, which guide an oscillating saw in a precisely determined resection plane. This plane again is identical with the prostheses' margins for mandibular body replacement. The use of this technique in four patients is reported on: after temporary insertion of the templates for resection and after resection, the prostheses were stabilized with the same screws in the same screw-holes where the templates had been. Resection and reconstruction were thus highly precise, safe and fast and primarily led to excellent aesthetic and functional results. Wound-healing depends on a safe soft-tissue reconstruction over these large prostheses. Coverage with flaps seems obligatory. In spite of the superior technical aspects, the clinical long-term results of this new technique were poor.

Adult↗
PubMed2000

Internal quality control in virology: validation of immunoassays using a personal computer spreadsheet.

Design of a spreadsheet to evaluate the performance of internal quality control sera used for the validation of immunoassays in virology is described. Developed using Microsoft Excel 97, it can set target limits and analyse control data by application of Westgard quality control rules. It also provides a permanent record of all relevant information concerning each assay run, including action taken to rectify unacceptable performance.

Humans↗
PubMed2001

HIDE: a new hybrid environment for the design of custom-made hip prosthesis.

This technical note describes a new software environment (HIPCOM design environment, HIDE) for the design of custom-made total hip replacements. These devices are frequently designed using general-purpose mechanical computer-aided design (CAD) programs using a set of bone contours extracted from the computer tomography (CT) images as anatomical reference. On the contrary, the HIDE system was developed to let the operator directly design the stem shape onto the CT images in a single-step operation. The operator can directly import CT data in DICOM format or use special functions to reconvert to a digital stack, the CT images printed on a radiological film. Once the stack of CT images is loaded, the operator can design the implant shape by imposing control sections directly on the CT images. The interpolation of these control sections produces the basic 3D shape of the custom-made stem. The shape is then exported to the CAD-computer-aided manufacturing (CAM) program to refine the design and to generate the part program to manufacture the implant with a CNC tooling machine. Using HIDE, the duration of design steps it affected was reduced by more than 50% with respect to the standard method in use at the manufacturer site. HIDE also improved the accuracy and the repeatability of the whole procedure. The learning curve became flat after only ten cases. These good results were achieved because of the integration of the vectorial description of the prosthetic component with the raster description of the CT data that allowed the designer to use all details available in the CT images.

Computer-Aided Design↗
PubMed2000

The Procera abutment--the fifth generation abutment for dental implants.

The Brånemark dental implant has undergone progressive development in terms of both the implant body itself and the components connecting the implant to the prosthesis. Many screw and abutment designs have been developed, with various degrees of success. About 15 years ago, CAD (computer-assisted design)-CAM (computer-assisted manufacture) technology was introduced to dentists. More recently CAD-CAM has been used in the manufacture of abutments for implants. This article reviews currently available techniques for creating the Procera custom abutment (Nobel Biocare, Göteborg, Sweden) and outlines appropriate applications for this type of implant.

Computer-Aided Design↗
PubMed2004

Design requirements for ubiquitous computing environments for healthcare professionals.

Ubiquitous computing environments can support clinical administrative routines in new ways. The aim of such computing approaches is to enhance routine physical work, thus it is important to identify specific design requirements. We studied healthcare professionals in an emergency room and developed the computer-augmented environment NOSTOS to support teamwork in that setting. NOSTOS uses digital pens and paper-based media as the primary input interface for data capture and as a means of controlling the system. NOSTOS also includes a digital desk, walk-up displays, and sensor technology that allow the system to track documents and activities in the workplace. We propose a set of requirements and discuss the value of tangible user interfaces for healthcare personnel. Our results suggest that the key requirements are flexibility in terms of system usage and seamless integration between digital and physical components. We also discuss how ubiquitous computing approaches like NOSTOS can be beneficial in the medical workplace.

Computer Graphics↗
PubMed1994

Computational molecular modeling in peptide drug design.

The review concentrates on practical applications of computer molecular modeling in peptide drug design. The examples of the predictions (successful or not) made by computational modeling before synthesis of peptide analogs, not the explanations provided after synthesis and biological testing of peptides, are discussed. The review spans over 20 years of predictions made by computer molecular modeling for bradykinin, angiotensin, thyrotropin-releasing factor, tuftsin, substance P, CCK-related peptides, luliberin, alpha-melanotropin and opioid peptides. The described examples are discussed in terms of finding the optimal way to use computer modeling for peptide design. The step-by-step 'technology' of peptide design is outlined in detail.

Amino Acid Sequence↗
PubMed1980

Design of mirror systems for commercial vehicles.

This paper describes a computer aided design project for the evaluation of alternative mirror systems for a range of commercial vehicles. Computer modelling of mirror systems introduces the ergonomics parameters into the design programme at an early stage. The flexibility of computer modelling allows a far greater range of designs to be evaluated. The problems can be studied and resolved before producing a series of mirror designs to be evaluated by more conventional techniques on prototype vehicles. Mirrors designed in this way are less likely to require major redesign. Compliance with the legislative requirements of mirror design was a major consideration. Attempts were also made to optimise mirror systems for a range of cabs basing the evaluations on ergonomic as well as legislative criteria. Additionally, consideration was given to the use of mirrors for viewing trailer swing, passenger exit surveillance (for public service vehicles) and the viewing of objects close to high cabs. SAMMIE (System for Aiding Man-Machine Interaction Evaluation), a computer-aided workplace and work task design system, was used to model the vehicles and to produce the required mirror views on a computer graphics terminal.

Journal Article↗
PubMed1993

Optimisation of dose distribution for linear accelerator-based stereotactic radiosurgery.

The work presented in the paper addresses a method for obtaining the optimal dose distribution for LINAC-based stereotactic radiosurgery. As many targets have nonspherical or irregular shapes and three-dimensional dose calculations included in dose optimisation, long computation times are required to determine the optimum isocentre separation and collimator sizes to shape the irregular target using the multiple-isocentre approach, by trial-and-error types of method. The simple approach, using a computer-aided design optimisation technique and a fast approximate dose model, has been developed to find the optimum isocentre positions and collimator sizes quickly and automatically. A spherical dose model has been developed to represent the dose for a standard arc system with a single isocentre. The implementation of computer-aided design algorithms with the spherical dose model and their application to several cases are discussed. It is shown that the spherical dose model gives dose distribution similar to that of the exact dose model, which makes this simple dose model more efficient, with computer-aided design optimisation, in finding optimum isocentre positions and collimator sizes used in stereotactic radiosurgery.

Humans↗
PubMedDate not supplied

Evaluation of an open-loop, computer-based infusion system designed to achieve a series of constant, targeted plasma procainamide concentrations in patients undergoing electrophysiologic testing.

STUDY OBJECTIVE: To evaluate the performance of a computer-based procainamide infusion system in patients undergoing electrophysiologic testing. DESIGN: Prospective case series. SETTING: Electrophysiology laboratory in a university hospital. PATIENTS: Thirty-four patients with inducible sustained ventricular tachycardia. INTERVENTIONS: Intravenous infusion of procainamide to achieve and maintain targeted plasma concentrations. MEASUREMENTS AND MAIN RESULTS: System performance was assessed by comparing targeted and observed plasma concentrations. The population median absolute performance error (size of typical miss) was 12.6% (95% CI 11.2-14.1%). The population median performance error (system bias) was not significantly different from zero. A small but statistically significant improvement in performance over time was observed (population absolute performance error divergence -0.125%/min). Population wobble (overall system stability) was 7.6% (95% CI 6.8-8.3%). Population-based estimates of central compartment volume and volume of distribution at steady state were significantly higher and lower, respectively, than estimates used by the infusion system. CONCLUSION: The computer-based infusion system is capable of achieving and maintaining a series of targeted procainamide concentrations in patients undergoing electrophysiologic testing.

Adult↗
PubMed2000

The effect of arm and wrist supports on the load of the upper extremity during VDU work.

OBJECTIVE: To evaluate the effectiveness of arm and wrist supports in reducing the workload during computer work. DESIGN: Female subjects (n=10) performed computer work in conditions with arm or wrist supports and in a condition without supports. BACKGROUND: Sustained muscle tension in the trapezius muscle is a risk factor for trapezius myalgia. Arm and wrist supports are used at the workplace with the intention to reduce the muscle tension. The effectiveness of these aids in reducing the load is not clear. METHODS: A typing task and mouse task were performed, each with four types of supports and without support. Electromyography and subjective ratings were used to quantify the workload. RESULTS: Lower levels of trapezius muscle activation were recorded with the use of arm supports. Wrist supports did not reduce activation. The rated perceived workload did not discriminate. CONCLUSIONS: Reduction of muscle activation in the neck-shoulder region during standard visual display unit work can be achieved with arm supports. Wrist supports do not reduce the strain on the neck-shoulder region. Subjective ratings seem not of use in selecting ergonomic aids in low intensity tasks. RelevanceVisual display unit workers are at risk of developing complaints of the neck and upper extremity. Arm and wrist supports are introduced at the workplace to reduce the workload. If arm and wrist supports are effective in reducing the workload they might be of use as preventive measures to reduce the risk of neck-shoulder complaints.

Adult↗
PubMedDate not supplied

Rational combinatorial library design. 3. Simulated annealing guided evaluation (SAGE) of molecular diversity: a novel computational tool for universal library design and database mining.

We have developed a novel method for molecular diversity sampling called SAGE (simulated annealing guided evaluation of molecular diversity). Compounds in chemical databases or virtual combinatorial libraries are conventionally represented as points in multidimensional descriptor space. The SAGE algorithm selects a desired number of optimally diverse points (compounds) from a database. The diversity of a subset of points is measured by a specially designed diversity function, and the most diverse subset is selected using Simulated Annealing (SA) as the optimization tool. Application of SAGE to two simulated data sets of randomly distributed points in two-dimensional space afforded diverse and representative selection as judged by visual inspection. SAGE was also applied, in comparison with random sampling, to two other simulated data sets with points distributed among many clusters. We found that SAGE sampling covered significantly more clusters than the random sampling. By defining a fraction of data points as active, we also compared SAGE with random sampling in terms of hit rates. We showed that when the percentage of active points was low, the hit rates obtained by SAGE were always higher than those obtained by random sampling. When the percentage of active points was high, the performance of SAGE, in terms of individual hit rates, depended upon the data structure. However, in all cases, SAGE performed better than random sampling when cluster hit rates were used as the criterion.

Algorithms↗
PubMedDate not supplied

Design of a computer-assisted programme supporting the selection and clinical management of patients referred for liver transplantation.

The paper describes the knowledge-base of the expert system OLT 1, developed to support medical decision-making in patients referred for liver transplantation. The paper goes through the real clinical problems, and describes both structural (organization of the domain knowledge) and functional aspects (reasoning algorithm and strategies for clinical decision). According to the programme, patients referred to Liver Transplant Centres may be enrolled and ranked in the waiting list, included in a stand-by list for treatment and re-evaluation, or discharged. All decisions are made on the basis of well-assessed and objective criteria.

Aged↗
PubMed2006

Construction of resolvable spatial row-column designs.

Resolvable row-column designs are widely used in field trials to control variation and improve the precision of treatment comparisons. Further gains can often be made by using a spatial model or a combination of spatial and incomplete blocking components. Martin, Eccleston, and Gleeson presented some general principles for the construction of robust spatial block designs which were addressed by spatial designs based on the linear variance (LV) model. In this article we define the two-dimensional form of the LV model and investigate extensions of the Martin et al. principles for the construction of resolvable spatial row-column designs. The computer construction of efficient spatial designs is discussed and some comparisons made with designs constructed assuming an autoregressive variance structure.

Analysis of Variance↗
PubMed2003

[The reconstruction of three-dimension morphology of proximal femur].

OBJECTIVES: To reconstruct the morphology of the proximal femur and measure the parameters of them by means of the computer-aided design (CAD) in order to provide help to the design and research of the domestic prosthesis, event for the selection of the adapted implant for the doctors before operation. METHODS: The data of 160 healthy Chinese proximal femur images were obtained by the PHLLIP SR7000 computer tomography. The correlative parameters were measured exactly by medical imaging software. Then the imaging data were input into an computerized contouring program which generates the three dimensional coordinates representing periosteal and endosteal contours of the femur for each CT slice. Though the computer-aided design (CAD) software, the three-dimensional solid model was reconstructed by the vectorisation of image contours. In the circumstance of CAD system, the bone axis is defined as the line across the geometric center of the cross-section of the isthmus and 20 mm above the lesser trochanter mid-point. We measured the parameters of the endosteal and periosteal dimensions of the medullary canal. RESULTS: The parameters of the medullary canal measured with the reconstructed normal Chinese femur have significant difference from that measured with the Caucasian's. The extracortical and endosteal parameters of male have significant differences from most of female's. However, there were no significant differences in endosteal width between different age groups in two gender groups. From the proximal to the distal femur, the intersection angles between the longest mediolateral endosteal diameters of the slices and the plane of the femoral neck were increased. CONCLUSIONS: The reconstructive femur contains more information and can be cut at arbitrary levels which means it is facility to the research of the Morphology of the Proximal femur and the measurement of relative parameters. It is necessary to design the prosthesis which fit anatomic parameters of the Chinese femur. It needs to further study whether the gender factor will be considered in the prosthesis design. The angle between the anteversion and the helitorsion at the level 20 mm above the lesser trochanter midpoint should be noticed by the implant designers and doctors.

Aged↗