نتایج جستجو برای: bright light
تعداد نتایج: 415955 فیلتر نتایج به سال:
Malignant glioma is the most common type of primary central nervous system cancer. Gliomas are very difficult to completely resect due to their invasiveness. In the present study, we compared fluorescence-guided and standard bright-light resection of a human glioma orthotopically implanted in nude mice. U87 human glioma cells, expressing red fluorescent protein (RFP), were injected stereotactic...
We have obtained stationary bright spatial solitons in a planar photorefractive strontium barium niobate waveguide for visible light ranging from 514.5 to 780 nm. Even for larger wavelengths (lambda=1047 nm) strong self-focusing of the beam was observed; however, input power had to be some orders of magnitude higher than for visible light for self-focusing to occur. Furthermore, we found transi...
1. Disorders of the iris sphincter that may require pharmacologic testing — cholinergic super-sensitivity vs. under-sensitivity: When evaluating an anisocoria that increases in bright light and decreases in dim light, attention usually shifts toward the pupil that is larger in bright light to determine if a paresis of the iris sphincter paresis is present. The causes are either from denervation...
This study explores the effect of continuous exposure to bright light on neuromelanin formation and dopamine neuron survival in the substantia nigra. Twenty-one days after birth, Sprague-Dawley albino rats were divided into groups and raised under different conditions of light exposure. At the end of the irradiation period, rats were sacrificed and assayed for neuromelanin formation and number ...
Light can influence physiology and performance of humans in two distinct ways. It can acutely change the level of physiological and behavioral parameters, and it can induce a phase shift in the circadian oscillators underlying variations in these levels. Until recently, both effects were thought to require retinal light perception. This view was challenged by Campbell and Murphy, who showed sig...
Bright light resets the human circadian pacemaker independent of the timing of the sleep-wake cycle.
Human circadian rhythms were once thought to be insensitive to light, with synchronization to the 24-hour day accomplished either through social contacts or the sleep-wake schedule. Yet the demonstration of an intensity-dependent neuroendocrine response to bright light has led to renewed consideration of light as a possible synchronizer of the human circadian pacemaker. In a laboratory study, t...
We investigate the conditions necessary for bright squeezed light generation through second harmonic generation inside a crystalline whispering-gallery mode resonator. We show that the variance of a coherent mode can be reduced by a factor of 9 due to low loss through a nonlinear medium. This results in a one-step process that can generate efficient bright squeeze light at a desired wavelength.
We tested the hypothesis that circadian adaptation to night work is best achieved by combining bright light during the night shift and scheduled sleep in darkness. Fifty-four subjects participated in a shift work simulation of 4 day and 3 night shifts followed by a 38-h constant routine (CR). Subjects received 2,500 lux (Bright Light) or 150 lux (Room Light) during night shifts and were schedul...
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