The accumulation of bacteriochlorophyll in Rhodobacter capsulatus grown either anaerobically or under low aeration is repressed by bright light. It has been proposed that an intact photosynthetic membrane system is required for light-mediated regulation. This was tested by measuring bacteriochlorophyll accumulation in various mutant strains grown under 3% oxygen. Mutants lacking either the reac...

SLEEPINESS OFTEN OCCURS IN THE EARLY MORNING AND AFTERNOON.1,2 INCREASED SLEEPINESS HAS BEEN RECOGNIZED NOT ONLY AS A CAUSE OF automobile accidents, but also as a detriment to work efficiency in our business life.3-6 Several strategies have been examined as methods for controlling this sleepiness, such as taking caffeine,7-9 blowing cold air on the face,10 listening to the radio,10 chewing gum,...

PURPOSE A recent study suggests that transcranial brain targeted light treatment via ear canals may have physiological effects on brain function studied by functional magnetic resonance imaging (fMRI) techniques in humans. We tested the hypothesis that bright light treatment could improve psychomotor speed in professional ice hockey players. METHODS Psychomotor speed tests with audio and visu...

When suspensions of Halobacterium halobium are exposed to bright light, the light-scattering properties of the bacteria change. This light-scattering response can produce a transmission decrease of about 1% throughout the red and near-infrared region. The action spectrum for the light-scattering response appropriately matches the absorption spectrum of bacteriorhodopsin. The response is elimina...

BACKGROUND Some small controlled studies have found that dawn simulation is effective in treating seasonal affective disorder (SAD). With a larger sample size and a longer duration of treatment, we compared dawn simulation with bright light therapy and a placebo condition in patients with SAD. METHOD Medication-free patients with SAD were randomly assigned to one of three conditions: bright l...

Manipulating the speed of light has never been more exciting since electromagnetic induced transparency and its classical analogs led to slow light. Here, we report the manipulation of light group velocity in a terahertz metamaterial without needing a dark resonator, but utilizing instead two concentric split-ring bright resonators (meta-atoms) exhibiting a bright Fano resonance in close vicini...

"Flow" is a positive emotional state which typically occurs when a person perceives a balance between the challenges associated with a situation and his or her capabilities to accomplish these demands. While flow often occurs along with positive feelings and high introspective performance, only a few studies have investigated how it is associated with cognitive performance (i.e., objective perf...

BACKGROUND Despite evidence that bright light can improve mood, the neurobiology remains poorly understood. Some evidence implicates the catecholamines. In the present study, we measured the effects of transiently decreasing dopamine (DA) synthesis on mood and motivational states in healthy women with mild seasonal mood changes who were tested in either bright or dim light. METHODS On 2 test ...

Effects of two different light intensities during daytime were examined on human circadian rhythms in plasma melatonin, core body temperature, and wrist activity under a fixed sleep schedule. Sleep qualities as indicated by polysomnography and subjective sleepiness were also measured. In the first week, under dim light conditions ( approximately 10 lx), the onset and peak of nocturnal melatonin...

Dark grown albescent corn seedlings are deficient in colored carotenoids but accumulate phytoene, phytofluene and an unidentified substance in the carotenol fraction. They bleach upon exposure to bright light and appear albino. Seedlings grown under low level incandescent light are normal in appearance and contain almost as much colored carotenoid as control seedlings. The existing leaf tissue ...