Search results for "wave"
showing 10 items of 6009 documents
Quantifying coordination and coordination variability in backward versus forward running: Implications for control of motion
2015
The aims of this study were to compare coordination and coordination variability in backward and forward running and to investigate the effects of speed on coordination variability in both backward and forward running. Fifteen healthy male participants took part in this study to run forwards and backwards on a treadmill at 80%, 100% and 120% of their preferred running speeds. The coordinate data of passive reflective markers attached to body segments were recorded using motion capture systems. Coordination of shank-foot and thigh-shank couplings in sagittal plane was quantified using the continuous relative phase method. Coordination variability was calculated as the standard deviation of a…
Human eyes do not need monochromatic aberrations for dynamic accommodation
2017
Purpose To determine if human accommodation uses the eye's own monochromatic aberrations to track dynamic accommodative stimuli. Methods Wavefront aberrations were measured while subjects monocularly viewed a monochromatic Maltese cross moving sinusoidally around 2D of accommodative demand with 1D amplitude at 0.2 Hz. The amplitude and phase (delay) of the accommodation response were compared to the actual vergence of the stimulus to obtain gain and temporal phase, calculated from wavefront aberrations recorded over time during experimental trials. The tested conditions were as follows: Correction of all the subject's aberrations except defocus (C); Correction of all the subject's aberratio…
Effects of corticotropin-releasing hormone on respiratory parameters during sleep in normal men.
2009
Corticotropin-releasing hormone (CRH) is well-known to be a centrally acting respiratory stimulant after systemic application both in healthy subjects and in patients suffering from respiratory failure. In order to study the effects of CRH on sleep EEG and respiratory parameters during sleep, 14 healthy male volunteers were investigated in a single-blind placebo controlled design. After an adaptation night, polysomnography was performed during two successive nights between 23.00 hrs. and 7.00 hrs. During one night placebo was applied, on the other 50 μg ovine CRH was administered intravenously as a bolus every hour from 0.00 hrs. to 6.00 hrs. For the assessment of respiration, blood oxygen …
Accommodation Responds to Optical Vergence and Not Defocus Blur Alone.
2017
Purpose To determine whether changes in wavefront spherical curvature (optical vergence) are a directional cue for accommodation. Methods Nine subjects participated in this experiment. The accommodation response to a monochromatic target was measured continuously with a custom-made adaptive optics system while astigmatism and higher-order aberrations were corrected in real time. There were two experimental open-loop conditions: vergence-driven condition, where the deformable mirror provided sinusoidal changes in defocus at the retina between -1 and +1 diopters (D) at 0.2 Hz; and blur-driven condition, in which the level of defocus at the retina was always 0 D, but a sinusoidal defocus blur …
Don't stop me now: Hampered retrieval of action plans following interruptions
2020
How can we retrieve action plans in working memory (WM) after being distracted or interrupted? The present EEG study investigated this question using a WM task in which a random sequence of single numbers (1-4 and 6-9) was presented. In a given trial, participants had to decide whether the number presented in the preceding trial was odd or even. Additionally, interfering stimuli were randomly presented in 25% of all trials, requiring the participants to either ignore a colored number (distraction) or respond to it (interruption) while maintaining the previously formed action plan in WM. Our results revealed a detrimental impact of interruptions on WM performance in trials after interrupting…
Electromagnetically Generated Extracorporeal Shock Wave Lithotripsy and Adjuvant Combined Oral Litholysis for Therapy of Symptomatic Gallbladder Ston…
1991
A prospective study was conducted to evaluate effectivity, problems and adverse effects of extracorporeal shock wave lithotripsy (ESWL) using a newly developed electromagnetic biliary lithotriptor (Lithostar Plus, Siemens, Erlangen, FRG) for the treatment of selected patients presenting with symptomatic cholecystolithiasis. In addition to generally accepted criteria for the selection of patients, gallbladder contractility was established and pigment stones were excluded by computed tomography (CT). 80 out of 486 patients (63 females, 17 males, mean age 36, range 17-76 years) were selected for ESWL using a standardized diagnostic program. 62 out of 80 patients participating in the study had …
High-energy extracorporeal shock wave treatment of nonunions.
2001
Forty-three consecutive patients who did not have healing of tibial or femoral diaphyseal and metaphyseal fractures and osteotomies for at least 9 months after injury or surgery were examined prospectively for use of high-energy extracorporeal shock waves. Former treatment modalities (cast, external fixator, plate osteosynthesis, limitation of weightbearing) remained unchanged. In all cases a 99m Technetium dicarboxyphosphonate regional two-phase bone scintigraphy was performed before one treatment with 3000 impulses of an energy flux density of 0.6 mJ/mm 2 . Radiologic and clinical followups were done at 4-week intervals starting 8 weeks after shock wave treatment. The success criterion wa…
Influence of age on the interrelation between EEG frequency bands during NREM and REM sleep.
2004
The age-dependence of temporal interrelations between distinct frequency bands of sleep EEG was investigated in a group of 59 healthy young and middle-aged males via cross correlation analysis. Based on global evaluation throughout the entire night, a highly significant decline of the delta/theta correlation with increasing age was found. A separate analysis for non-rapid eye movement (NREM) and rapid eye movement (REM) sleep revealed different changes with aging. During NREM sleep, the correlation between the delta and theta frequency bands decreased with increasing age. In contrast, during REM sleep, a stronger correlation became obvious between the theta, alpha, and beta frequency bands …
Measurement of the local aortic stiffness by a non-invasive bioelectrical impedance technique.
2011
International audience; Aortic stiffness measurement is well recognized as an independent predictor of cardiovascular mortality and morbidity. Recently, a simple method has been proposed for the evaluation of the local aortic stiffness (AoStiff) using a non-invasive bioelectrical impedance (BI) technique. This approach relies on a novel interpretation of the arterial stiffness where AoStiff is computed from the measurement of two new BI variables: (1) the local aortic flow resistance (AoRes) exerted by the drag forces onto the flow; (2) the local aortic wall distensibility (AoDist). Herein, we propose to detail and compare these three indices with the reference pulse wave velocity (PWV) mea…
Effects of Clomipramine on Sleep EEG and Nocturnal Penile Tumescence
1988
The effects of the tricyclic antidepressant clomipramine on sleep EEG and nocturnal penile tumescence (NPT) were investigated during a long-term study in a normal male control subject. During 21 consecutive days the subject received first placebo for 3 days, then stepwise increasing dosages of clomipramine for 10 days, and finally placebo after withdrawal for 8 days. Under clomipramine, rapid eye movement (REM) sleep was suppressed markedly; an REM rebound occurred after withdrawal. Awake and stages 1 and 2 increased while slow wave sleep was diminished under clomipramine. Those non-REM parameters returned to baseline values after drug cessation. NPT was reduced simultaneously with REM slee…