Computerized Data Reduction Research Articles

Correction for Gravity in Isokinetic Dynamometry of Knee Extensors in Below Knee Amputees

In isokinetic dynamometry of the knee extensors the influence of gravity on the lower limb is often neglected. The aim of this study was to assess the shape, the quantity and reproducibility of the gravity correction curve (GCC). Eight amputees participated in this study. The GCC was produced on an isokinetic dynamometer (QD) throughout the range of motion on the amputated side with prosthesis and on the non-amputated side. The results were compared with the GCC calculated according to the Cybex data reduction computer procedure. The isokinetic torque registration of the QD is, in a mathematical way, a straight line (Pearson correlation coefficient greater than 0.99). The other GCC is shaped like a cosinus curve. The intra-individual reproducibility is high, the inter-individual variability substantial. An explanation for the difference between the two methods is discussed. For an ideal measurement of the muscular torque, one should not only correct for the effect of gravity but for all factors counteracting the effect of the knee extensors. In that case an individual GCC should be made directly with the dynamometer.

Computerized Data Reduction and Analysis in Positron Annihilation Coincidence Doppler Broadening Spectroscopy

Positron annihilation spectroscopy is a sensitive probe for studying the electronic structure of defects in solids. The high-momentum part of the Doppler-broadened spectra can be used to distinguish different elements at the annihilation site. This can be achieved by using a two-detector coincidence system, which reduces the peak to background ratio dramatically. The coincident events have to be extracted from a two-dimensional spectrum that is recorded by two high-purity germanium detectors. For this purpose the computer program MePASto was developed, which allows an automated data reduction from such Doppler-coincidence spectra, supplemented by a post-processing unit for data analysis. Additionally a case study of the identification of defect sites in an intermetallic compound is presented.

Annular Vane Swirler Performance

The flowfield immediately downstream of an annular vane swirler is investigated to aid in computer modeling of flowfields, and in the development and evaluation of turbulence models for swirling confined flow. The swirler studied is annular with a hub-to-swirler diameter ratio of 0.25, and 10 adjustable flat untwisted vanes with a pitch-to-chord ratio of 0.68. Measurements of time-mean axial, radial, and swirl velocities are made at the swirler exit plane, using a five-hole pitot probe technique with computer data reduction. The time-mean velocity components measured at the swirler exit plane show clearly the effects of centrifugal forces, recirculation zones, and blade wakes on the exit-plane velocity profiles. Nonaxisymmetry is present in all swirl cases investigated. Assumptions of flat axial and swirl profiles are found to be progressively less realistic as the swirl vane angle increases, with axial and swirl velocities peaking strongly at the outer edges of the swirler exit and significant nonzero radial velocities present.

Trusting computerized data reduction too much: a critique of Anderson's ambulatory respiratory monitor

Recording respiration ambulatorily in order to study stress and anxiety is an important and interesting topic that has been widely neglected in the past, principally due to technical difficulties. In contrast to heart rate measurements, which are very reliable with current ambulatory devices, respiratory measurements are much more susceptible to artifacts. Unfortunately, measuring inspired and expired air directly from a mask covering the mouth and nose is not practical for most ambulatory applications. Instead, elastic bands containing coils of insulated wire worn around the chest and abdomen are widely used (Respitrace bandsTM, Ambulatory Monitoring, Ardsley, NY). Their main disadvantage is that they react not only to respiratory activity, but also to postural changes, bending of the trunk, and vibrations of abdomen, chest, or breasts due to accelerative forces on the body during physical activity. Anderson and Frank (1990) designed a portable device containing a microprocessor that analyzes the output of those bands on-line to retrieve respiratory rate and depth (in units of inductance change) for each breath. These measures are averaged

Risk of tardive dyskinesia in older patients. A prospective longitudinal study of 266 outpatients.

Neuroleptic-induced tardive dyskinesia (TD) is a major iatrogenic disorder that is more prevalent among older patients. The objective of this study was to determine the incidence of and risk factors for TD in neuroleptic-treated patients over age 45 years. We studied 266 middle-aged and elderly outpatients with a median duration of 21 days of total lifetime neuroleptic exposure at study entry. Most patients were treated throughout the study with either a high-potency or a low-potency neuroleptic and maintained on relatively low doses. The patients were followed up at 1- to 3-month intervals with "blind" assessment of psychopathologic condition, clinically as well as instrumentally (ie, using electromechanical sensors with computerized data reduction, including spectral analysis) evaluated movement disorder, and global cognitive function. Cumulative incidence of TD was 26%, 52%, and 60% after 1, 2, and 3 years, respectively. The principal risk factors for TD were duration of prior neuroleptic use at baseline, cumulative amount of high-potency neuroleptics, history of alcohol abuse/dependence, borderline or minimal dyskinesia, and tremor on instrumental assessment. Use of higher amounts of neuroleptics, particularly high-potency ones, should be avoided in older patients, patients with alcohol abuse/dependence, or patients with a subtle movement disorder at baseline; these patients are at a higher risk of developing TD.

Calibration of the electrical aerosol analyzer at subambient pressures

A commercial Electrical Aerosol Analyzer (EAA, TSI Inc. model 3030) was calibrated experimentally at three subambient pressures (i. e., 0.901, 0.878, and 0.853 atm). Each calibration resulted in a 19 × 11 response matrix and a size dependent sensitivity curve \documentclass{article}\pagestyle{empty}\begin{document}$ \left({\frac{{pA}}{{{\# \mathord{\left/ {\vphantom {\# {cm^3}}} \right. \kern-\nulldelimiterspace} {cm^3}}}}} \right) $\end{document}. The results of the calibration were incorporated into a data reduction computer program for size distribution inversion. The accuracy of the calibration was tested by measuring the size distribution of a NaCl polydisperse aerosol at the three subambient pressures. All the tests gave good agreement in the inverted mean geometric diameter and geometric standard deviation of the aerosol number size distribution.

Near-Infrared Reflectance Analysis for Silicone Coating Weights

Contemporary NIR computer correlation methods, involving the measurement of reflected energy from solid surfaces, were developed in the late 60s, mainly through the efforts of Karl Norris of the United States Department of Agriculture. This early work involved the analysis of agricultural products for moisture, protein, and fat. In that period, methods development not only required extensive time and effort involving a large population of calibration samples but also required expensive computerized data reduction. It is easy to see how these problems imposed early economic constraints on the development of the field. Today, however, there is explosive activity in the NIR field. As noted by Buchanan and Honigs, as well as others, this resurgent interest in the near-infrared region stems from the current availability of inexpensive yet powerful computers. Analytical chemists are quickly discovering that near-infrared spectra of many common materials, including industrially important materials, are considerably less complex to interpret than spectra of the natural products that gave impetus to the original development of NIR computer correlation techniques.

Correction for gravity in isokinetic dynamometry of knee extensors in below knee amputees

In isokinetic dynamometry of the knee extensors the influence of gravity on the lower limb is often neglected. The aim of this study was to assess the shape, the quantity and reproducibility of the gravity correction curve (GCC). Eight amputees participated in this study. The GCC was produced on an isokinetic dynamometer (QD) throughout the range of motion on the amputated side with prosthesis and on the non-amputated side. The results were compared with the GCC calculated according to the Cybex data reduction computer procedure. The isokinetic torque registration of the QD is, in a mathematical way, a straight line (Pearson correlation coefficient greater than 0.99). The other GCC is shaped like a cosinus curve. The intra-individual reproducibility is high, the inter-individual variability substantial. An explanation for the difference between the two methods is discussed. For an ideal measurement of the muscular torque, one should not only correct for the effect of gravity but for all factors counteracting the effect of the knee extensors. In that case an individual GCC should be made directly with the dynamometer.

A solid phase enzyme immunoassay (ELISA) for the detection and quantitation of anticardiolipin antibody.

A solid-phase enzyme-linked immunoabsorbent assay (ELISA) is described for the detection and quantitation of anticardiolipin antibodies (ACAs) IgG and IgM in sera. In these assays, non-specific binding was controlled by using antigen-negative wells for all serum dilutions tested. Quadruplicate 100-microliters serum samples diluted 1:20 for ACA-IgG and 1:40 for ACA-IgM were incubated for two hours, after which alkaline phosphatase-conjugated antihuman IgG or IgM was added. A standard serum was used on each plate to provide reproducibility of the assay. Upper limits of normal for ACA-IgG and IgM were established by testing 161 sera from normal persons. Sixty-one selected patients with SLE were tested; and, from these results, categories of positivity were defined from negative to 4+. All screen-positive sera (greater than or equal to 1+) were assayed in a quantitative ELISA assay for ACAs, using multiple dilutions of the unknowns. These data were fit on a standard curve generated with dilutions of a reference serum on each plate using a computerized data reduction system based on the 2 Plus 2 model. The standard curves were compared with the international standards for IgG and IgM anticardiolipin. The ability to quantitate ACA concentrations allows better definition of positive sera, as well as the opportunity to accurately evaluate and follow this antibody in a variety of patient groups.

The role of robotics in the laboratory of the 80s

A new technology, robotics, already being used in other fields, is slated to have a major impact in automating operations and procedures performed in chemistry laboratories during the eighties. Introduced only 5 years ago, it has become the fastest growing new technology for the laboratory. An introduction to laboratory robotics, which combines the technologies of chemistry, analytical instrumentation, computers and robotics, will be presented first. Laboratory automation, once limited to computerized data reduction, can now include sample handling and sample preparation, wet chemistry procedures, and instrumental analysis. Laboratory robots, utilizing programmable computers, can be easily reprogrammed to do a variety of laboratory procedures and thus, do not require a large quantity of identical, repetitive operations to justify the investment in capital and time. Examples will be given in automated sample preparation for a variety of trace organic and inorganic analyses. GC and HPLC applications represent 40% of the current installed base of 1000 laboratory robotic systems. Trace chromatographic assays require many steps (i.e., filtering, extraction, evaporation, etc.) and put tremendous strain on laboratory personnel to maintain acceptable precision levels. Laboratory robotics systems typically improve precision by a factor of 2 or 3 and maintain that precision over extended periods of time. Derivatization, which is routinely used in trace chromatographic analyses, can be easily automated with robotics and eliminates the analyst's exposure to highly reactive chemicals. Robotics systems can also perform analyses in a serialized mode versus a batch mode. Serialization allows each sample to have the same time history, important in derivatization experiments where possible side reactions can occur causing increased error. Serialization also increases the throughput of samples versus a batch mode. Automation of wet digestion procedures for trace inorganic analyses has been accomplished using laboratory robotics. Manual procedures require constant attention by an experienced chemist while being exposed to corrosive chemicals and fumes. Laboratory robotics is finding increased use in microbiological laboratories where a sterile environment must be maintained and care must be taken so that people do not contaminate the experiments. To improve their utility in the laboratory, robotic systems often must with standard analytical instruments. This may include a mechanical handshake to put the sample into the instrument as well as an electronic interface. The electronic interface can be as simple as turning the instrument on and off to completely controlling all parameters on the front panel. Interfaces are available for GC, HPLC, UV/VIS, NMR, titrators, viscometers, computers, ICP, physical testing instruments, etc. Bar code reading systems can also be interfaced to robotic systems allowing sample identification and method selection to be automatically entered. Laboratory robotics is having an impact on analytical methods, laboratory layout, staffing, type of staffing and work flow. This new level of automation, achieved with laboratory robotics, brings substantial gains in laboratory performance.

Transient method for measuring thermal conductivity

A method is described for evaluating thermal conductivity of materials on the basis of the time rate of change of temperature along the central axis of a cylindrical test specimen heated by an instantaneously applied, axially located constant heat source. The method has been adapted to the laboratory measurement of thermal conductivity of finite-diameter specimens of dielectric materials. It is particularly adaptable to the use of automatic data acquisition and computer data reduction to provide rapid availability of test results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Process monitoring and quality assurance of polymeric materials by computerized pyrolysis mass spectrometry

The potentialities of computerized pyrolysis mass spectrometry (m.s.) are discussed for applications in process monitoring and quality assurance involving nonvolatile materials such as polymers. The traditional obstacles to more widespread acceptance of pyrolysis m.s. for industrial applications are reviewed in the light of recent developments which provide a major reduction in the cost, size and complexity of the equipment. Rapid advances in computerized data reduction, evaluation and interpretation methods for complex mass-spectral patterns are also transforming the classical “fingerprinting” concept of pyrolysis m.s. into a much more detailed compositional and structural characterization approach. These new developments are illustrated by means of several practial examples ranging from quality control of clinically important polyurethanes to monitoring of wood pulping processes and of growth phenomena in microbial cultures.

Descriptive Measures of Isokinetic Trunk Testing

Measurements of isokinetic parameters during trunk flexion and extension were collected for 44 untrained adult subjects (23 females, 21 males) using a Cybex(R) 11 dynamometer and trunk stabilization system interface to a Cybex Data Reduction Computer. On each of three days, subjects performed two sets (trials) of maximal extension/flexion contractions. One trial consisted of four repetitions each at the isokinetic speeds of 30, 60, 90, and 120 degrees /sec. Data interpretation consisted of: Peak torque, range of motion from the initiation of contraction to peak torque, total range of motion, total work performed, total power generated, torques produced relative to body weight, and flexion/extension torque and work ratios. It was concluded that isokinetic testing of the trunk can provide clinically useful guidelines for trunk evaluation and rehabilitation when a large data base is collected for subject populations with various physical characteristics. J Orthop Sports Phys Ther 1985;7(2):43-49.

TFTR diagnostic control and data acquisition system

General computerized control and data-handling support for TFTR diagnostics is presented within the context of the Central Instrumentation, Control and Data Acquisition (CICADA) System. Procedures, hardware, the interactive man–machine interface, event-driven task scheduling, system-wide arming and data acquisition, and a hierarchical data base of raw data and results are described. Similarities in data structures involved in control, monitoring, and data acquisition afford a simplification of the system functions, based on ‘‘groups’’ of devices. Emphases and optimizations appropriate for fusion diagnostic system designs are provided. An off-line data reduction computer system is under development.

From micro to mainframe. A practical approach to perinatal data processing.

A new, practical approach to perinatal data processing for a large obstetric population is described. This was done with a microcomputer for data entry and a mainframe computer for data reduction. The Screen Oriented Data Access (SODA) program was used to generate the data entry form and to input data into the Apple II Plus computer. Data were stored on diskettes and transmitted through a modern and telephone line to the IBM 370/168 computer. The Statistical Analysis System (SAS) program was used for statistical analyses and report generations. This approach was found to be most practical, flexible, and economical.

A Universal Data Base Approach For Quantitative WDXRF Analysis With General Purpose Data Acquisition Algorithms

AbstractAcquisition of new x—ray fluorescence (XRF) hardware or a data reduction computer can be a particularly frustrating experience for analysts who depend upon programs not supplied by the XRF spectrometer manufacturer. Computerized data collection and reduction pragrams generated for a particular spectrameter/computer system can become virtually useless when a significant part af the spectrometer/computer system is replaced. The problem is compounded in a research environment where many different kinds of samples are encountered and many unique analysis programs developed.The potential magnitude of this problem was recently demonstrated at the Ford Motor Company Scientific Research Laboratory when the thirteen year old computer-contolled XRF analysis system was replaced by a new state-of-the-art spectrometer/computer system.

Surface characterization of intact fibers by inverse gas chromatography

AbstractInverse gas chromatography (IGC) was used to determine adsorption isotherms and isosteric heats of adsorption for several normal alkanes on a number of intact textile fibers and to determine the specific surface areas of these fibers. Surface areas obtained by IGC were in excellent agreement (except for cotton) with those calculated from the geometric dimensions of circular cross‐section fibers and with those obtained by the adsorption of krypton. Heats of adsorption were found to be only slightly higher than the corresponding heats of liquefaction of the probes. The effect of fiber surface purity on adsorption behavior as well as computerized data reduction are briefly discussed.

PADRE: A Computerized Data Reduction System for Cascade Impactor Measurements

An interactive computer resource for analyzing, evaluating, and archiving particle size distributions as determined by cascade impactors for environmental measurement is decribed. The Particle Data Reduction (PADRE) computer program assists users in obtaining high quality size-mass distribution data for archival in the Fine Particle Emissions Information System (FPEIS). PADRE users interactively store, edit, reduce, and analyze observed impactor data from anywhere in the continential United States. Extensive data quality checks and computer- prompted, user-directed program operations assist users in obtaining meaningful information within minutes of entering impactor data. Design goals, program operation, sample sessions and plans for future system development are discussed.

Norms for High School Football Players Derived from Cybex Data Reduction Computer

Three hundred and forty-two male high school football players, ranging in age from 15 to 17, were screened for muscular imbalances and joint abnormalities about the knee using a Cybex II lsokinetic Dynamometer and Cybex Data Reduction Computer. Each player was tested at speeds of 60, 240, 300 degrees , and 300" per second for muscular work. The athletes were classified by position (quarterback, runningback, tight end, wide receiver, linemen, linebacker, and defensive back). Several parameters were reported: peak torque with gravity effect for both extensors and flexors, peak torque to body weight, opposing muscle group ratios, torque acceleration energy, work over a preselected number of repetitions, endurance ratio, and agonist-antagonist work ratios. The purpose of the screening was to provide data beneficial for the prevention of injury from muscular imbalance and joint instability, data useful as clinical guidelines for rehabilitation and return to play, and suggestions for strength training programs. Previous articles have been published showing peak torque, and quadriceps and hamstring ratios, as a means of preventing injury due to muscular imbalance. However, until the introduction of the Cybex(R) Data Reduction Computer, authors had no way of taking the effect of gravity on the lower limb into consideration when presenting their findings. Hamstring-quadricep ratios, once thought to be ideal at 60% or better at 60 degrees per second are now better set at 50 to 55% with gravity effect at 60 per second. The intent of this paper is not to draw any specific conclusions but to present meaningful data for the purpose of preseason screening to prevent injuries and to aid in strength-training programs.J Orthop Sports Phys Ther 1984;5(5):243-245.

40 years of development in radioisotope imaging

The development of gamma -ray imaging techniques can be traced from the pinhole camera with X-ray film recording of the image-a hopelessly insensitive technique. A major step towards improved sensitivity was to increase the absorption of incident gamma -radiation in the detector by using a suitable crystal. Detection of the emitted light quanta improved from the photographic film by way of the image intensifier until high gain photomultiplier tubes became commercially available. By about 1955 and for the next decade, the rectilinear scanner dominated the field of clinical gamma -ray imaging; this was also the period when 131I was by far the most widely used radionuclide in medicine. By 1958 Anger had already built the first gamma camera, probably five years before its time, closely followed by the positron camera. Probably the most important advance in the 1960s was not the rapid technical developments in instrumentation but a modest paper presented by Harper in 1964 on the clinical use of 99Tcm. Recently there have been technical developments in computer data reduction and processing. The dominant role of the gamma camera and 'region of interest' facilities has tended to encourage the superstition that the human body is a two-dimensional object. The increasing interest in tomographic imaging represents a return to reality, but the increased amount of information required means the use of even shorter lived radionuclides.