keyword
MENU ▼
Read by QxMD icon Read
search

Dim light

keyword
https://www.readbyqxmd.com/read/28334493/glucose-metabolism-in-mammalian-photoreceptor-inner-and-outer-segments
#1
REVIEW
Daniel S Narayan, Glyn Chidlow, John Pm Wood, Robert J Casson
Photoreceptors are the first order neurons of the visual pathway, converting light into electrical signals. Rods and cones are the two main types of photoreceptors in the mammalian retina. Rods are specialized for sensitivity at the expense of resolution and are responsible for vision in dimly lit conditions. Cones are responsible for high acuity central vision and colour vision. Many human retinal diseases are characterized by a progressive loss of photoreceptors. Photoreceptors consist of four primary regions: outer segments, inner segments, cell bodies, and synaptic terminals...
March 23, 2017: Clinical & Experimental Ophthalmology
https://www.readbyqxmd.com/read/28331380/classical-conditioning-for-preserving-the-effects-of-short-melatonin-treatment-in-children-with-delayed-sleep-a-pilot-study
#2
Annette van Maanen, Anne Marie Meijer, Marcel G Smits, Frans J Oort
Melatonin treatment is effective in treating sleep onset problems in children with delayed melatonin onset, but effects usually disappear when treatment is discontinued. In this pilot study, we investigated whether classical conditioning might help in preserving treatment effects of melatonin in children with sleep onset problems, with and without comorbid attention deficit hyperactivity disorder (ADHD) or autism. After a baseline week, 16 children (mean age: 9.92 years, 31% ADHD/autism) received melatonin treatment for 3 weeks and then gradually discontinued the treatment...
2017: Nature and Science of Sleep
https://www.readbyqxmd.com/read/28327443/correcting-delayed-circadian-phase-with-bright-light-therapy-predicts-improvement-in-adhd-symptoms-a-pilot-study
#3
Rachel E Fargason, Aaron D Fobian, Lauren M Hablitz, Jodi R Paul, Brittny A White, Karen L Cropsey, Karen L Gamble
Attention-deficit/hyperactivity disorder (ADHD) is a common condition with comorbid insomnia reported in >70% of children and adults. These patients demonstrate delays in sleep-wake rhythms, nocturnal rise in melatonin, and early morning rise in cortisol. Given that standard psychopharmacologic treatments for ADHD often do not completely control symptoms in participants with circadian rhythm delay, we sought to test whether bright light therapy (BLT) advances circadian rhythms and further reduces ADHD symptoms over standard treatments...
March 6, 2017: Journal of Psychiatric Research
https://www.readbyqxmd.com/read/28318721/-physiology-of-the-visual-retinal-signal-from-phototransduction-to-the-visual-cycle
#4
REVIEW
C Salesse
The retinal photoreceptors (rods and cones) are responsible for light absorption and transduction of the signal, which is transmitted to the other retinal nerve cells and then to the brain. The chromophore of visual pigments of rods and cones is a particular isomer of a vitamin A derivative. Light absorption by this chromophore leads to its isomerization and to a phototransduction cascade, which results in photoreceptor hyperpolarization and cessation of glutamate secretion at their synaptic terminals. Phototransduction of cones and rods differs in their signal amplification and inactivation, which is consistent with their respective functions...
March 17, 2017: Journal Français D'ophtalmologie
https://www.readbyqxmd.com/read/28296912/infants-perception-of-lightness-changes-related-to-cast-shadows
#5
Kazuki Sato, So Kanazawa, Masami K Yamaguchi
When humans perceive the lightness of an object's surface in shadows there is an implicit assumption that cast shadows dim the surface. In two experiments, we investigated whether 5- to 8-month-old infants make this assumption about shadows. According to this shadow assumption, the apparent change in lightness produced by shadows on an object's surface are attributed to blocked light sources. If infants can use the shadow assumption to perceive the object's lightness in shadows, they will also be able to detect unnatural lightness changes in shadows...
2017: PloS One
https://www.readbyqxmd.com/read/28296058/a-comparison-between-the-larval-eyes-of-the-dimly-luminescent-keroplatus-nipponicus-and-the-brightly-luminescent-arachnocampa-luminosa-diptera-keroplatidae
#6
V Benno Meyer-Rochow, Yumi Yamahama
Larvae of the weakly blue-luminescent fungus gnat Keroplatus nipponicus possess on either side of their heads a small black stemmatal eye with a plano-convex lens approximately 25 μm in diameter. In total, 12-14 retinula cells give rise to a centrally fused rhabdom of up to 8 μm in diameter. The rhabdom's constituent microvilli, approximately 70 nm in width, are roughly orthogonally oriented, a requirement for polarization sensitivity. Screening pigment granules are abundant in the retinula cells and measure at least 1 μm in diameter...
March 9, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28295969/identification-and-characterization-of-the-luc2-type-luciferase-in-the-japanese-firefly-luciola-parvula-involved-in-a-dim-luminescence-in-immobile-stages
#7
Manabu Bessho-Uehara, Yuichi Oba
Nocturnal Japanese fireflies, Luciola parvula, emit from their lanterns a yellow light, one of the most red-shifted colors found among fireflies. Previously, we isolated and characterized two different types of luciferase gene, Luc1 and Luc2, from the fireflies Luciola cruciata and Luciola lateralis; Luc1 is responsible for the green-yellow luminescence of larval and adult lanterns, whereas Luc2 is responsible for the dim greenish glow of eggs and pupal bodies. The biological role of firefly lanterns in adults is related to sexual communication, but why the eggs and pupae glow remains uncertain...
March 9, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28286917/characterizing-sleep-in-adolescents-and-adults-with-autism-spectrum-disorders
#8
S E Goldman, M L Alder, H J Burgess, B A Corbett, R Hundley, D Wofford, D B Fawkes, L Wang, M L Laudenslager, B A Malow
We studied 28 adolescents/young adults with autism spectrum disorders (ASD) and 13 age/sex matched individuals of typical development (TD). Structured sleep histories, validated questionnaires, actigraphy (4 weeks), and salivary cortisol and melatonin (4 days each) were collected. Compared to those with TD, adolescents/young adults with ASD had longer sleep latencies and more difficulty going to bed and falling asleep. Morning cortisol, evening cortisol, and the morning-evening difference in cortisol did not differ by diagnosis (ASD vs...
March 12, 2017: Journal of Autism and Developmental Disorders
https://www.readbyqxmd.com/read/28285255/relationships-between-circadian-measures-depression-and-response-to-antidepressant-treatment-a-preliminary-investigation
#9
Leslie M Swanson, Helen J Burgess, Edward D Huntley, Holli Bertram, Ann Mooney, Jennifer Zollars, Richard Dopp, Robert Hoffmann, Roseanne Armitage, J Todd Arnedt
Few studies have examined relationships between circadian rhythms and unipolar major depressive disorder. Further, no study to date has examined circadian markers as predictors of response to depression treatment. In the present study, we examined associations between circadian timing and its alignment with sleep and depression severity in 30 adults with major depressive disorder who completed a randomized controlled trial of two weeks of time in bed (TIB) restriction administered adjunctive to fluoxetine, with a focus on sex differences...
March 8, 2017: Psychiatry Research
https://www.readbyqxmd.com/read/28283577/distinct-roles-of-light-activated-channels-trp-and-trpl-in-photoreceptors-of-periplaneta-americana
#10
Paulus Saari, Andrew S French, Päivi H Torkkeli, Hongxia Liu, Esa-Ville Immonen, Roman V Frolov
Electrophysiological studies in Drosophila melanogaster and Periplaneta americana have found that the receptor current in their microvillar photoreceptors is generated by two light-activated cationic channels, TRP (transient receptor potential) and TRPL (TRP-like), each having distinct properties. However, the relative contribution of the two channel types to sensory information coding by photoreceptors remains unclear. We recently showed that, in contrast to the diurnal Drosophila in which TRP is the principal phototransduction channel, photoreceptors of the nocturnal P...
March 10, 2017: Journal of General Physiology
https://www.readbyqxmd.com/read/28280566/the-transiting-dust-clumps-in-the-evolved-disc-of-the-sun-like-uxor-rz-psc
#11
Grant M Kennedy, Matthew A Kenworthy, Joshua Pepper, Joseph E Rodriguez, Robert J Siverd, Keivan G Stassun, Mark C Wyatt
RZ Psc is a young Sun-like star, long associated with the UXor class of variable stars, which is partially or wholly dimmed by dust clumps several times each year. The system has a bright and variable infrared excess, which has been interpreted as evidence that the dimming events are the passage of asteroidal fragments in front of the host star. Here, we present a decade of optical photometry of RZ Psc and take a critical look at the asteroid belt interpretation. We show that the distribution of light curve gradients is non-uniform for deep events, which we interpret as possible evidence for an asteroidal fragment-like clump structure...
January 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28276854/activity-sleep-and-ambient-light-have-a-different-impact-on-circadian-blood-pressure-heart-rate-and-body-temperature-rhythms
#12
D G Gubin, D Weinert, S V Rybina, L A Danilova, S V Solovieva, A M Durov, N Y Prokopiev, P A Ushakov
The aim of the present study was to investigate the impact of endogenous and exogenous factors for the expression of the daily rhythms of body temperature (BT), blood pressure (BP) and heart rate (HR). One hundred and seventy-three young adults (YA), 17-24 years old (y.o.), of both genders were studied under a modified constant-routine (CR) protocol for 26 h. Participants were assigned randomly to groups with different lighting regimens: CR-LD, n = 77, lights (>400 l×) on from 09:00 to 17:00 h and off (<10 l×) from 17:00 to 09:00 next morning; CR-LL, n = 81, lights on (>400 l×) during the whole experimental session; CR-DD, n = 15, constant dim light (<10 l×) during the whole experiment...
February 16, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28270559/a-single-night-light-exposure-acutely-alters-hormonal-and-metabolic-responses-in-healthy-participants
#13
Mohammed S Albreiki, Benita Middleton, Shelagh M Hampton
Many animal studies have reported an association between melatonin suppression and the disturbance of metabolic responses; yet, few human studies have investigated bright light effects on metabolic and hormonal responses at night. This study investigated the impact of light on plasma hormones and metabolites prior to, and after, an evening meal in healthy participants. Seventeen healthy participants, 8 females (22.2 ± 2.59 years, mean ± s.d.) and 9 males (22.8 ± 3.5 years) were randomised to a two-way cross-over design protocol; dim light (DL) (<5 lux) and bright light (BL) (>500 lux) sessions, separated by at least seven days...
February 2017: Endocrine Connections
https://www.readbyqxmd.com/read/28262507/influence-of-refractive-error-on-pupillary-dynamics-in-the-normal-and-mild-traumatic-brain-injury-mtbi-populations
#14
James Q Truong, Nabin R Joshi, Kenneth J Ciuffreda
PURPOSE: There have been several studies investigating static, baseline pupil diameter in visually-normal individuals across refractive error. However, none have assessed the dynamic pupillary light reflex (PLR). In the present study, both static and dynamic pupillary parameters of the PLR were assessed in both the visually-normal (VN) and the mild traumatic brain injury (mTBI) populations and compared as a function of refractive error. METHODS: The VN population comprised 40 adults (22-56 years of age), while the mTBI population comprised 32 adults (21-60 years of age) over a range of refractive errors (-9...
March 2, 2017: Journal of Optometry
https://www.readbyqxmd.com/read/28257779/photoregulation-of-photosystem-ii-activity-mediated-by-cytoplasmic-streaming-in-chara-and-its-relation-to-ph-bands
#15
Alexander A Bulychev, Anna V Komarova
Chloroplasts in vivo exposed to strong light export assimilates and excess reducing power to the cytoplasm for metabolic conversions and allocation to neighboring and distant organelles. The cytoplasmic streaming, being particularly fast in characean internodes, distributes the exported metabolites from brightly illuminated cell spots to light-limited regions, which is evident from the transient increase in chlorophyll fluorescence of shaded areas in response to illumination of distant cell regions situated upstream the liquid flow...
February 28, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28256534/cell-type-specific-epigenomic-analysis-reveals-a-uniquely-closed-chromatin-architecture-in-mouse-rod-photoreceptors
#16
Andrew E O Hughes, Jennifer M Enright, Connie A Myers, Susan Q Shen, Joseph C Corbo
Rod photoreceptors are specialized neurons that mediate vision in dim light and are the predominant photoreceptor type in nocturnal mammals. The rods of nocturnal mammals are unique among vertebrate cell types in having an 'inverted' nuclear architecture, with a dense mass of heterochromatin in the center of the nucleus rather than dispersed clumps at the periphery. To test if this unique nuclear architecture is correlated with a unique epigenomic landscape, we performed ATAC-seq on mouse rods and their most closely related cell type, cone photoreceptors...
March 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28250185/epistatic-interactions-influence-terrestrial-marine-functional-shifts-in-cetacean-rhodopsin
#17
Sarah Z Dungan, Belinda S W Chang
Like many aquatic vertebrates, whales have blue-shifting spectral tuning substitutions in the dim-light visual pigment, rhodopsin, that are thought to increase photosensitivity in underwater environments. We have discovered that known spectral tuning substitutions also have surprising epistatic effects on another function of rhodopsin, the kinetic rates associated with light-activated intermediates. By using absorbance spectroscopy and fluorescence-based retinal release assays on heterologously expressed rhodopsin, we assessed both spectral and kinetic differences between cetaceans (killer whale) and terrestrial outgroups (hippo, bovine)...
March 15, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28245865/can-tryptophan-supplement-intake-at-breakfast-enhance-melatonin-secretion-at-night
#18
Shunsuke Nagashima, Makoto Yamashita, Chiaki Tojo, Masayuki Kondo, Takeshi Morita, Tomoko Wakamura
BACKGROUND: Tryptophan (TRP) is an essential amino acid, and it has been suggested that TRP intake at breakfast combined with daytime bright light exposure can increase nocturnal melatonin secretion. However, the mechanisms involved are not yet clear. The aim of this study was to examine the effect of TRP supplement intake at breakfast on nocturnal melatonin secretion under different daytime light intensities in humans. METHOD: Twelve subjects (aged 21.3 ± 3...
February 28, 2017: Journal of Physiological Anthropology
https://www.readbyqxmd.com/read/28241159/timed-light-therapy-for-sleep-and-daytime-sleepiness-associated-with-parkinson-disease-a-randomized-clinical-trial
#19
Aleksandar Videnovic, Elizabeth B Klerman, Wei Wang, Angelica Marconi, Teresa Kuhta, Phyllis C Zee
Importance: Impaired sleep and alertness are some of the most common nonmotor manifestations of Parkinson disease (PD) and currently have only limited treatment options. Light therapy (LT), a widely available treatment modality in sleep medicine, has not been systematically studied in the PD population. Objective: To determine the safety and efficacy of LT on excessive daytime sleepiness (EDS) associated with PD. Design, Settings, and Participants: This randomized, placebo-controlled, clinical intervention study was set in PD centers at Northwestern University and Rush University...
February 20, 2017: JAMA Neurology
https://www.readbyqxmd.com/read/28237017/can-short-wavelength-depleted-bright-light-during-single-simulated-night-shifts-prevent-circadian-phase-shifts
#20
J Regente, J de Zeeuw, F Bes, C Nowozin, S Appelhoff, A Wahnschaffe, M Münch, D Kunz
In single night shifts, extending habitual wake episodes leads to sleep deprivation induced decrements of performance during the shift and re-adaptation effects the next day. We investigated whether short-wavelength depleted (=filtered) bright light (FBL) during a simulated night shift would counteract such effects. Twenty-four participants underwent a simulated night shift in dim light (DL) and in FBL. Reaction times, subjective sleepiness and salivary melatonin concentrations were assessed during both nights...
May 2017: Applied Ergonomics
keyword
keyword
38179
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"