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PubMed2001

In situ optical microscopic recording of slip line development during plastic deformation of Cu-15at%Al single crystals with high resolution--estimation of dislocation velocities.

Observations and measurements of slip line evolution during plastic deformation are performed by optical microscopic video recording. In addition, high resolution in time is achieved by means of photodiodes positioned in the intermediate image plane of the microscope. Examples of measurements at room temperature on short-range ordered Cu-15at%Al single crystals are given and evaluated to estimate the velocities of edge and screw dislocation groups from the observed rates of growth of slip steps in height and in length, respectively, on one side of the specimen. By means of a second microscope observing the opposite side, the average rates for the dislocations to cross the whole specimen can be obtained. The measured values are discussed in terms of the movement of correlated dislocation groups in the crystals.

Journal Article↗

PubMed1995

Electromyographic analysis of shoulder muscles of men with low-level paraplegia during a weight relief raise.

The purpose of this study was to define the demand on the shoulder musculature during performance of a weight relief raise. Intramuscular electromyographic activity of 12 shoulder muscles was recorded in 13 pain-free subjects with paraplegia while elevating the trunk from a sitting position. Upper extremity motion was determined by elbow electrogoniometry and video recordings. Three phases of the raise were analyzed: initial loading, lift, and hold. During the lift phase, high level triceps long head activity (54% manual muscle test [MMT]) produced elbow extension, whereas moderate- to high-level activity of the sternal pectoralis major (32% MMT) and latissimus dorsi (58% MMT) elevated the trunk on the fixed humerus. Deltoid, supraspinatus, infraspinatus, subscapularis, middle trapezius, serratus anterior, and biceps long head played minimal roles (< 25% MMT). Thoracohumeral muscle activity, by transferring the load on the humerus directly to the trunk, functionally circumvented the glenohumeral joint. This would reduce the potential for impingement of the rotator cuff.

Adult↗

PubMed2001

[Long-term monitoring].

The electroencephalography (EEG) keeps its essential role in the differential diagnosis of epileptic and non-epileptic seizure disorders and in the classification of the different types of epilepsies and epileptic seizures, mainly due to its unique capability to directly show epileptic malfunction. The routine EEG usually records the EEG between seizures (interictal EEG) and remains a cost effective, highly specific, but not very sensitive method in epileptology. However, a diagnosis based on clinical data and routine EEG alone if often difficult and 20-30% of patients referred to an epilepsy centre due to medical refractory seizures do not have epilepsy. The different methods of long-term monitoring (cable and radio telemetry, ambulatory EEG monitoring) can continuously record EEG and other biosignals for many hours up to several days and allow a direct assessment of seizures (ictal EEG). In combination with the video-recorded symptomatology, these methods establish a precise diagnosis and follow-up of uncertain seizure disorders in the majority of cases. Although technical and personnel investment is relatively high the method used in expert hands is efficient, accepted and cost effective.

Diagnosis, Differential↗

PubMed2005

A biomechanical comparison of four extensor tendon repair techniques in zone IV.

BACKGROUND: This study was designed to evaluate the biomechanical parameters of four different suture techniques specifically designed for zone IV extensor tendon injuries: the double figure of eight, the double modified Kessler, the six-strand double-loop, and the modified Becker suturing techniques. Ease of repair, tendon shortening, strength to 1-mm gap, strength to 2-mm gap, ultimate strength, and mode of repair failure were evaluated. METHODS: Twelve fresh-frozen cadaver hand-forearm units (48 fingers) were randomly assigned to the four suture repair treatments. The speed of tendon repair as performed by two matched-hand surgeons was recorded. Prerepair and postrepair tendon lengths were measured to document tendon shortening. The repair was stressed by linear distraction at 2.0 mm/minute using a servohydraulic frame. Video recordings of each distraction were independently reviewed for biomechanical parameters by three physician-observers in a double-blind setup. A one-way analysis of variance and t test analysis was performed. RESULTS: Results show that the double figure-of-eight technique and the double modified Kessler were significantly (p < 0.05) easier to perform at 7 minutes 31 seconds and 7 minutes 58 seconds, respectively, than the other two techniques. Tendon shortening ranged from 1.9 to 2.4 mm. There was no statistically significant difference in tendon shortening among the four techniques. Strength to 1-mm gap was significantly higher with the modified Becker technique, with a mean 28.8 +/- 8.0 N. This was followed by the six-strand double-loop technique, with 21.0 +/- 6.6 N, the double modified Kessler at 17.7 +/- 4.5 N, and the figure-of-eight technique at 17.5 +/- 2.4 N. Strength to 2-mm gap was significantly (p < 0.05) greater for the modified Becker technique and the modified Kessler technique at 56.0 +/- 9.2 N and 48.6 +/- 12.6 N, respectively, as compared with the other two suture methods. The modified Becker technique showed the highest ultimate strength at maximal loading at 63.3 +/- 7.8 N, followed by the double modified Kessler technique with strength of 56.8 +/- 14.8 N. Both were significantly stronger than the other two techniques. CONCLUSIONS: This study shows that the modified Becker suture technique, although not easily performed, proved to be the strongest repair, with a significantly greater resistance to 1-mm and 2-mm gap and the greatest ultimate strength on maximal loading.

Biomechanical Phenomena↗

PubMedDate not supplied

Nonepileptic events in childhood.

The medical records of 27 children admitted to the MINCEP Epilepsy Program for evaluation of intractable epilepsy but later shown to have nonepileptic events by EEG with simultaneous video monitoring were reviewed. Four groups were identified: pure psychogenic events (5 patients), psychogenic events plus epileptic seizures (3 patients), pure nonepileptic physiologic events (5 patients), and nonepileptic physiologic events plus seizures (14 patients). Historical data, physical examinations, and neurodiagnostic evaluations (including previous EEGs, neuroradiologic evaluations, and neuropsychologic testing) were reviewed. Children in all groups, except for those with pure psychogenic seizures, had a history of multiple seizure types identified by parents or caretakers. A history of status epilepticus was obtained in 64% (of 22 patients), including 11 of 14 patients with physiologic events plus seizures. Abnormal findings on neurologic examination were common, especially in children with nonepileptic physiologic events. All but two patients had a history of interictal epileptiform abnormalities on previous routine EEGs. Based on identification of nonepileptic events, antiepileptic drugs (AEDs) were discontinued completely in eight patients (30%) and the total number of AEDs was reduced in nine others (33%). A diagnosis of nonepileptic events should be considered in all children with refractory seizures or multiple seizure types. Abnormal findings on routine (interictal) EEG may actually confound the diagnosis. Intensive neurodiagnostic EEG-video recording is the preferred method for distinguishing nonepileptic from epileptic seizures.

Adolescent↗

PubMed1996

Validation of the Addiction Severity Index in French-speaking alcoholic patients.

OBJECTIVE: Evaluation of a French translation of the Addiction Severity Index (ASI) in 100 (78 male) alcoholic patients. METHOD: Validity of the instrument was assessed by measuring test-retest and interrater reliability, internal consistency and convergence and discrimination between items and scales. Concurrent validity was assessed by comparing the scores from the ASI with those obtained from three other clinimetric instruments. RESULTS: Test-retest reliability of ASI scores (after a 10-day interval) was good (r = 0.63 to r = 0.95). Interrater reliability was evaluated using six video recordings of patient interviews. Severity ratings assigned by six rates were significantly different (p < .05), but 72% of the ratings assigned by those who viewed the videos were within two points of the interviewer's severity ratings. Cronbach alpha coefficient of internal consistency varied from 0.58 to 0.81 across scales. The average item-to-scale convergent validity (r value) was 0.49 (range 0.0 to 0.84) for composite scores and 0.35 (range 0.00 to 0.68) for severity ratings, whereas discriminant validity was 0.11 on average (range-0.19 to 0.46) for composite scores and 0.12 (range-0.20 to 0.52) for severity ratings. Finally, concurrent validity with the following instruments was assessed: Severity of Alcoholism Dependence Questionnaire (40% shared variance with ASI alcohol scale), Michigan Alcoholism Screening Test (2% shared variance with ASI alcohol scale) and Hamilton Depression Rating Scale (31% shared variance with ASI psychiatric scale). CONCLUSIONS: The Addiction Severity Index covers a large scope of problems encountered among alcoholics and quantifies need for treatment. This French version presents acceptable criteria of reliability and validity.

Adult↗

PubMed1999

Diatom motility and low frequency electromagnetic fields--a new technique in the search for independent replication of results.

The hypothesis that exposure to a certain combination of static and alternating electromagnetic fields (EMFs) results in an increase in motility of the marine diatom Amphora coffeaeformis was tested. Diatom motility in three strains of A. coffeaeformis was positively correlated with extracellular calcium ion (Ca2+) concentration. The test apparatus consisted of two pairs of Helmholtz coils supported around the stage of a microscope linked to a video recorder and monitor. This system allowed real-time in vivo recordings of diatom speed under EMF and control exposures. The EMFs were calculated at calcium resonance values, previously found to cause enhanced motility. Computerised image analysis was used to calculate the distance moved by individual diatoms in 2-min periods before, during and after EMF or sham-EMF (control) exposure. The addition of EMF caused no significant increase in diatom motility. The results are discussed in relation to the use of diatom motility to measure EMF exposure effects.

Calcium↗

PubMed1986

Video and digital fluorescein angiography.

A video recording system, which provides real-time imaging and instant reporting of retinal fluorescein angiograms, with improved patient comfort, is described. Digital image-processing methods can be applied to video angiograms to improve image quality, quantitate retinal blood flow, measure areas, improve storage and access, and send images via phone lines or other electronic communication channels. Video image quality is somewhat inferior to conventional photographic techniques, but is more than adequate for diagnostic interpretation.

Computer Communication Networks↗

PubMed1997

Nicotine induces leukocyte rolling and adhesion in the cerebral microcirculation of the mouse.

Nicotine and several related metabolites were examined for their ability to induce leukocyte rolling and adhesion in the cerebral microcirculation of the mouse. A cranial window was surgically prepared for the visualization of the pial microcirculation using an intra-vital microscopy imaging system. Using this technique rhodamine-labeled leukocytes could be visualized and video-recorded as they traveled within the microvessels, and the quantitation of their rolling and adhesion along the pial venule walls was assessed during an off-line video playback analysis. Nicotine was found to produce significant dose-related increases in leukocyte rolling and adhesion. Cotinine, a major nicotine metabolite, did not induce the same degree of leukocyte rolling and adhesion. Mecamylamine, a nicotine antagonist, was found to inhibit the nicotine-induced leukocyte rolling and adhesion. Anti-P-selectin antibody blocked nicotine-induced leukocyte rolling, while anti-CD18 antibody effectively inhibited leukocyte adhesion, but not rolling in similar experiments. Nicotine-induced leukocyte rolling and adhesion were also inhibited by superoxide dismutase and catalase. These data suggest that nicotine, the principle pharmacological agent in cigarette smoke and related tobacco products, acts via a ganglionic-type nicotinic receptor to enhance leukocyte rolling via P-selectin and reactive oxygen radical-dependent mechanisms in cerebral microcirculation of the mouse.

Administration, Topical↗

PubMed1987

Behavior of chickens prior to death from sudden death syndrome.

A study was made to determine if chickens dying from sudden death syndrome (SDS) showed any unusual behavioral characteristics during the final 12 h preceding death. Continuous video recordings were made of floor pens of 50 to 120 individually marked male broiler chickens between 3 and 10 wk of age. Behavioral data were obtained from video tapes played back following death of chickens from SDS. Analysis of the video tapes revealed no significant differences between 10 SDS chickens and their matched controls in the frequencies or proportions of time spent in each of 19 different behavioral activities. All SDS chickens exhibited a sudden attack prior to death lasting an average of 53 s and characterized by loss of balance, violent flapping, and strong muscular contractions. There was no evidence that death was preceded by a particular environmental or behavioral event. It was concluded that there were no consistent behavioral symptoms which could be used to identify SDS chickens prior to death.

Animals↗

PubMed1991

Back disorders and nonneutral trunk postures of automobile assembly workers.

A case-referent study was conducted in an automobile assembly plant to evaluate the health effect of trunk postures, such as bending and twisting, that deviate from anatomically neutral. Cases of back disorders were all those of workers who reported back pain to the medical department in a ten-month period and met the severity criteria of an interview. The referents were randomly selected workers free of back pain according to medical department records, an interview, and an examination. For each of the final 95 cases and 124 referents, the job was analyzed for postural and lifting requirements with a video recording and software analysis system by analysts blinded to the case/referent status. Back disorders were associated with mild trunk flexion [odds ratio (OR) 4.9, 95% confidence interval (95% CI) 1.4-17.4], severe trunk flexion (OR 5.7, 95% CI 1.6-20.4), and trunk twist or lateral bend (OR 5.9, 95% CI 1.6-21.4). The risk increased with exposure to multiple postures and increasing duration of exposure.

Adult↗

PubMed1994

Arthropod model systems for studying complex biological processes in the space environment.

Three arthropod systems are discussed in relation to their complementary and potential use in Space Biology. In a next biosatellite flight, Drosophila melanogaster pre-adapted during several months to different g levels will be flown in an automatic device that separates parental from first and second generations. In the same flight, flies will be exposed to microgravity conditions in an automatic unit in which fly motility can be recorded. In the International Microgravity Laboratory-2, several groups of Drosophila embryos will be grown in Space and the motility of a male fly population will be video-recorded. In the Biopan, an ESA exobiology facility that can be flown attached to the exterior of a Russian biosatellite, Artemia dormant gastrulae will be exposed to the space environment in the exterior of the satellite under a normal atmosphere or in the void. Gastrulae will be separated in hit and non-hit populations. The developmental and aging response of these animals will be studied upon recovery. With these experiments we will be able to establish whether exposure to the space environment influences arthropod development and aging, and elaborate on some of the cellular mechanisms involved which should be tested in future experiments.

Aging↗

PubMed2005

Blink rate decreases with eyelid squint.

PURPOSE: We hypothesize that eyelid squint inhibits blink rate. This is part of a larger hypothesis that, because eyelid squint improves vision under conditions of optical defocus and/or glare, and reduced blink rate is assumed to contribute to dry eye symptoms, eyelid squint is part of the mechanism resulting in asthenopia. This study investigates the effect of voluntary eyelid squint on blink activity and on electromyography (EMG) measures from the orbicularis oculi. METHODS: Ten subjects (18 to 38 years of age) performed 3 1-minute trials each (Latin Square order) of voluntary target squint levels of 5%, 20%, 35%, and 50% with respect to previously demonstrated 0% (relaxed) and 100% (maximum) squint levels. EMG recordings using surface electrodes were obtained from the orbicularis muscle. Vertical dimension of the palpebral fissure and eye lid blinks were measured with an ISCAN eye tracker and video recorder. RESULTS: Each target squint level produced significant changes (p<0.0001) in ocular aperture size, EMG power, and EMG amplitude. For target voluntary squint levels of 5%, 20%, 35%, and 50%, the mean squint responses were 24%, 35%, 42%, and 53%, respectively. Blink rate was inversely related to both target squint level and squint response (p<0.0001), decreasing from 15 blinks per minute at 0% squint to 7.5 blinks per minute at 5% target voluntary squint and to 4 blinks per minute at 50% target voluntary squint. CONCLUSIONS: Voluntary eyelid squint significantly reduces blink rate by an average of 50% or more dependent on attempted level. Further study is required to determine if involuntary squint causes the same. All tested levels of voluntary squint resulted in an EMG signal from the orbicularis muscle that is measurably different from resting state. This indicates that EMG can be used as a reliable indicator of eyelid squint.

Adult↗

PubMed1997

The effects of walls, paternity and ageing on sperm motility.

The measurement of sperm motility is critical when studying fertilization kinetics and chemotaxis. Analysis of motility has traditionally been carried out on cells in small fluid volumes on microscope slides. Several theoretical treatments suggest that drag forces significantly affect flagellar motion within 10 sperm body lengths of the slide surface. Understanding how sperm move in the absence of surface drag is crucial when considering natural locomotory patterns. To examine the effects of solid surfaces, motile sperm from sea urchins (Arbacia punctulata) were placed in a Plexiglas chamber (69 mmx45 mmx15.5 mm; length x width x height). A system was constructed to minimize convective flow by limiting temperature differences within the chamber to less than 0.1 degrees C. The movement of sperm was video-recorded at two levels: (3/4)100 micron (3 body lengths) and 5 mm (150 body lengths) below the chamber lid. When swimming speeds were measured using a computerized video motion-analysis system, a highly significant difference (P<0. 0001) between cells at the two depths was found. Cells nearest the lid swam at 174.6+/-5.9 micron s-1 (mean +/- s.e.m.), whereas those farther away slowed to only 111.1+/-9.9 micron s-1 (mean +/- s.e.m.). Swimming speed was also found to be significantly (P<0.01) affected by paternity, but not by sperm age. We conclude that viscous wall effects must be carefully considered in studies of sperm motility and chemotaxis. The analysis of sperm on a microscope slide may substantially exaggerate swimming speed.

Animals↗

PubMed1978

A TV system for image recording and processing in conventional transmission electron microscopy.

An image processing system for a CTEM is described which is particularly suited for the imaging of radiation-sensitive objects. It consists of an image intensifier device for single electron counting, a digital storage unit and a video recorder for intermediate storage of low-dose image series. During on-line operation the information can be transferred to a computer for further processing. The output can be transferred onto a second digital storage unit and observed on a monitor. The influence on the DQE of the pulse height distribution of the single electron video signals and of a multiple counting are eliminated by means of special electronic components. Various modes of operation and application possibilities of the image processing system are discussed.

Computers↗

PubMed2000

Video analysis of standing--an alternative footprint analysis to assess functional loss following injury to the rat sciatic nerve.

The rat sciatic nerve is a well-established animal model for the study of recovery from peripheral nerve injuries. Footprint analysis is the most widely used non-invasive method of measuring functional recovery after injury in this model. We describe a new alternative video analysis of standing (or static footprint video analysis) to assess functional loss following injury to the rat sciatic nerve, during animal standing or periodic rest on a flat transparent surface. We found good correlation between video recording during standing and dynamic ink track footprint parameter measurements for both 1-5 and injured 2-4 toe spreads only. Reproducibility for these three parameters was also better using the video method. Uninjured 2-4 toe spread by video showed a poor correlation and similar reproducibility as compared with ink. However, both print length parameters measured by video had poorer correlation and greater variability, particularly the print length factor (PLF) was weakly correlated with that determined by ink. Contribution of the footprint factors on the estimated functional loss has also changed in conditions during standing. It was most prominent for the 1-5 toe spread factor (TSF), near marginal for the 2-4 or intermediary toe spread factor (ITF), and weak, statistically insignificant for the PLF. Thus, the introduction of a new functional loss index, or so-called static sciatic index (SSI), and its estimating formula was mandatory. Moreover, using a simple ratio of injured/uninjured 1-5 video toe spread as a substitute for the SSI, we could achieve considerable simplification of the method without any significant loss of accuracy. Our video analysis of standing is technically easier to perform than the corresponding footprint video analysis during walking, but still preserves all advantages of video versus conventional ink track method, i.e. there are few non-measurable footprints, better repeatability, high accuracy and more precise quantification of the degree of functional loss after sciatic nerve injury in the rat.

Animals↗

PubMed1994

Abnormal spontaneous movements in infants with repeated sleep apnoeas.

Infants with repeated apnoea during sleep have received great attention for the assumed reason of being at-risk for sudden infant death. The present paper reports findings which indicate a different risk, namely for neurological impairment during infancy due to repeated hypoxia. A very strong correlation exists between the respiratory measurements based on a polygraphic all-night recording (PtcO2 drops and apnoea incidence and duration) and the impairment of the spontaneous movement repertoire in 114 infants, aged between 3 and 26 weeks. All infants have been video recorded at the same day as the registration of the sonogram. As there was a gradient of respiratory abnormalities from absent to severe, a similar gradient was present in the degree of motor deviations in these infants. A variety of qualitative changes in the spontaneous movement patterns was found which was similar to those previously described in cases with documented brain damage. These abnormalities could not be attributed to pre- and perinatal complications. It is concluded that infants with repeated sleep apnoea need special attention for prevention of neurological impairment irrespective of the supposed risk for sudden infant death.

Female↗

PubMed1998

Muscle activity in the slalom turn of alpine skiing and in-line skating.

The electromyographic (EMG) activity of seven muscles of the trunk and lower extremity in five male masters level ski racers during a slalom turn in both alpine skiing and in-line skating was recorded using a telemetry system. Measurements were made on separate testing days using slopes commonly used in each activity (24 slope alpine skiing, 5 in-line skating). Qualitative video recorded at 60 Hz was analyzed to partition the turning cycle in both slalom skiing and in-line skating into initiation and turning phases. The EMG data from each turning cycle were normalized to standard isometric contractions (SIC's) for each muscle in order to quantitatively compare the amplitude characteristics of each phase of the turning cycle in both slalom skiing and in-line skating. The turning phase of in-line skating was found to be significantly longer (55%) than in slalom skiing, most likely due to significantly lower subject velocities recorded during in-line skating (8.5 m/s vs 10.2 m/s). All muscles were active at moderate to high levels (48-172% of SIC) during each phase of the turning cycle in both slalom skiing and in-line skating. The EMG amplitude characteristics were similar for six of the muscles in both slalom skiing and in-line skating for each of the turning phases. Only the erector spinae displayed significantly higher average and peak amplitudes in slalom skiing for both phases. It is concluded that the muscle activity patterns associated with the slalom turn of in-line skating are similar but notably more quasi-static than in slalom skiing.

Adult↗