Retinal light exposures can decrease melatonin production at night. Since nocturnal melatonin suppression by light has been implicated as an endocrine disruptor and linked to certain diseases, such as diabetes, obesity and cancer, it is important to be able to estimate a threshold light level needed to reliably suppress melatonin. The present study was designed to develop a working threshold fo...

The human circadian pacemaker, with an intrinsic period between 23.9 and 24.5 hr, can be reset by low levels of light. Biomathematical models of the human clock predict that light-dark cycles consisting of only approximately 3.5 lux during 16 hr of wakefulness and 0 lux during 8 hr of sleep should entrain approximately 45% of the population. However, under real-life conditions, sleep-wake sched...

OBJECTIVES To determine what percentage of out-of-hospital laryngoscopes meet a predetermined minimal illumination criterion and what factors may be altered to improve illumination. METHODS This was an observational study of the illumination of laryngoscopes currently in use by the Emergency Health Services of Nova Scotia. Each laryngoscope was measured at baseline. This illumination was comp...

results the results show the artificial lighting obtained by difference methods of the overall lighting from natural lighting in closed blinds mode equal to 266 lux and night lighting 283.5 lux that they have no significant differences with each other (p = 0.269). as well as the illumination intensity obtained from a standard grid method is 283.5 lux and illumination intensity based on luminair...

Biofilm formation by Vibrio fischeri is a complex process involving multiple regulators, including the sensor kinase (SK) RscS and the response regulator (RR) SypG, which control the symbiosis polysaccharide (syp) locus. To identify other regulators of biofilm formation in V. fischeri, we screened a transposon library for mutants defective in wrinkled colony formation. We identified LuxQ as a p...

Biosensors based on luminescent bacteria may be valuable tools to monitor the chemical quality and safety of surface and drinking water. In this review, an overview is presented of the recombinant strains available that harbour the bacterial luciferase genes luxCDABE, and which may be used in an online biosensor for water quality monitoring. Many bacterial strains have been described for the de...

The aim of this study was to investigate the effect of exposure to dim light at night (dLAN) when sleeping on functional brain activation during a working-memory tasks. We conducted the brain functional magnetic resonance imaging (fMRI) analysis on 20 healthy male subjects. All participants slept in a polysomnography laboratory without light exposure on the first and second nights and under a d...

It has been shown in animal studies that exposure to brief pulses of bright light can phase shift the circadian pacemaker and that the resetting action of light is most efficient during the first minutes of light exposure. In humans, multiple consecutive days of exposure to brief bright light pulses have been shown to phase shift the circadian pacemaker. The aim of the present study was to dete...

Major research efforts are directed towards the development of a better antimycobacterial vaccine. But progress in the field of tuberculosis vaccine development has been hampered by the lack of human in vitro models to assess vaccine immunogenicity and efficacy. New candidate vaccines will have to be evaluated against the existing Mycobacterium bovis BCG "gold standard." It is therefore importa...