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https://www.readbyqxmd.com/read/28529525/melatonin-in-tuberous-sclerosis-complex-analysis-using-modern-mathematical-modeling-methods
#1
Justyna Paprocka, Marek Kijonka, Łukasz Boguszewicz, Maria Sokół
Purpose. The aim of the study was to assess melatonin secretion pattern in children with TSC and to compare it with the secretion patterns in children with and without epilepsy. Material and Methods. Melatonin secretion was measured every three hours using the RIA method in four children with recognized TSC. The parameters of the melatonin secretion models were interpreted and compared with those obtained for the patients with epilepsy (n = 76) and the children from the control, nonepileptic group (n = 36)...
2017: International Journal of Endocrinology
https://www.readbyqxmd.com/read/28526480/human-seasonal-and-circadian-studies-in-antarctica-halley-75-0-s
#2
Josephine Arendt, Benita Middleton
Living for extended periods in Antarctica exposes base personnel to extremes of daylength (photoperiod) and temperature. At the British Antarctic Survey base of Halley, 75(0)S, the sun does not rise for 110 d in the winter and does not set for 100 d in summer. Photoperiod is the major time cue governing the timing of seasonal events such as reproduction in many species. The neuroendocrine signal providing photoperiodic information to body physiology is the duration of melatonin secretion which reflects the length of the night: longer in the short days of winter and shorter in summer...
May 16, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28522084/circadian-phase-dynamics-of-subjective-sleepiness-and-sensitivity-to-blue-light-in-young-adults-complaining-of-a-delayed-sleep-schedule
#3
Christophe Moderie, Solenne Van der Maren, Marie Dumont
OBJECTIVE: To assess factors that might contribute to a delayed sleep schedule in young adults with sub-clinical features of delayed sleep phase disorder. METHODS: Two groups of 14 young adults (eight women) were compared: one group complaining of a delayed sleep schedule and a control group with an earlier bedtime and no complaint. For one week, each subject maintained a target bedtime reflecting their habitual sleep schedule. Subjects were then admitted to the laboratory for the assessment of circadian phase (dim light melatonin onset), subjective sleepiness, and non-visual light sensitivity...
June 2017: Sleep Medicine
https://www.readbyqxmd.com/read/28500770/the-role-of-melatonin-in-the-neurodevelopmental-etiology-of-schizophrenia-a-study-in-human-olfactory-neuronal-precursors
#4
Tania Galván-Arrieta, Citlali Trueta, Montserrat G Cercós, Marcela Valdés-Tovar, Salvador Alarcón, Julian Oikawa, Horacio Zamudio-Meza, Gloria Benítez-King
Dim light exposure of the mother during pregnancy has been proposed as one of the environmental factors that affect the fetal brain development in schizophrenia. Melatonin circulating levels are regulated by the environmental light/dark cycle. This hormone stimulates neuronal differentiation in the adult brain. However, little is known about its role in the fetal human brain development. Olfactory neuronal precursors (ONPs) are useful for studying the physiopathology of neuropsychiatric diseases because they mimic all the stages of neurodevelopment in culture...
May 13, 2017: Journal of Pineal Research
https://www.readbyqxmd.com/read/28499591/chronic-exposure-to-dim-artificial-light-at-night-decreases-fecundity-and-adult-survival-in-drosophila-melanogaster
#5
L K McLay, M P Green, T M Jones
The presence of artificial light at night is expanding in geographical range and increasing in intensity to such an extent that species living in urban environments may never experience natural darkness. The negative ecological consequences of artificial night lighting have been identified in several key life history traits across multiple taxa (albeit with a strong vertebrate focus); comparable data for invertebrates is lacking. In this study, we explored the effect of chronic exposure to different night-time lighting intensities on growth, reproduction and survival in Drosophila melanogaster...
May 10, 2017: Journal of Insect Physiology
https://www.readbyqxmd.com/read/28489826/a-rhodopsin-in-the-brain-functions-in-circadian-photoentrainment-in-drosophila
#6
Jinfei D Ni, Lisa S Baik, Todd C Holmes, Craig Montell
Animals partition their daily activity rhythms through their internal circadian clocks, which are synchronized by oscillating day-night cycles of light. The fruitfly Drosophila melanogaster senses day-night cycles in part through rhodopsin-dependent light reception in the compound eye and photoreceptor cells in the Hofbauer-Buchner eyelet. A more noteworthy light entrainment pathway is mediated by central pacemaker neurons in the brain. The Drosophila circadian clock is extremely sensitive to light. However, the only known light sensor in pacemaker neurons, the flavoprotein cryptochrome (Cry), responds only to high levels of light in vitro...
May 10, 2017: Nature
https://www.readbyqxmd.com/read/28472667/the-effects-of-spectral-tuning-of-evening-ambient-light-on-melatonin-suppression-alertness-and-sleep
#7
Shadab A Rahman, Melissa A St Hilaire, Steven W Lockley
We compared the effects of bedroom-intensity light from a standard fluorescent and a blue- (i.e., short-wavelength) depleted LED source on melatonin suppression, alertness, and sleep. Sixteen healthy participants (8 females) completed a 4-day inpatient study. Participants were exposed to blue-depleted circadian-sensitive (C-LED) light and a standard fluorescent light (FL, 4100K) of equal illuminance (50lx) for 8h prior to a fixed bedtime on two separate days in a within-subject, randomized, cross-over design...
May 1, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28470119/acute-effects-of-morning-light-on-plasma-glucose-and-triglycerides-in-healthy-men-and-men-with-type-2-diabetes
#8
Ruth I Versteeg, Dirk J Stenvers, Dana Visintainer, Andre Linnenbank, Michael W Tanck, Gooitzen Zwanenburg, Age K Smilde, Eric Fliers, Andries Kalsbeek, Mireille J Serlie, Susanne E la Fleur, Peter H Bisschop
Ambient light intensity is signaled directly to hypothalamic areas that regulate energy metabolism. Observational studies have shown associations between ambient light intensity and plasma glucose and lipid levels, but human data on the acute metabolic effects of light are scarce. Since light is the main signal indicating the onset of the diurnal phase of physical activity and food intake in humans, we hypothesized that bright light would affect glucose and lipid metabolism. Therefore, we determined the acute effects of bright light on plasma glucose and lipid concentrations in 2 randomized crossover trials: (1) in 8 healthy lean men and (2) in 8 obese men with type 2 diabetes...
April 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28465542/the-importance-of-illumination-in-nest-site-choice-and-nest-characteristics-of-cavity-nesting-birds
#9
Paweł Podkowa, Adrian Surmacki
Light has a significant impact on many aspects of avian biology, physiology and behaviour. An increasing number of studies show that illumination may positively influences birds' offspring fitness by e.g. acceleration of embryo development, stimulation of skeleton growth or regulation of circadian rhythm. Because nest cavities have especially low illumination, suitable light levels may be especially important for species which nest there. We may therefore expect that birds breeding in relatively dim conditions should prefer brighter nest sites and/or evolve behavioral mechanisms to secure sufficient light levels in the nest...
May 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28452285/daily-light-exposure-patterns-reveal-phase-and-period-of-the-human-circadian-clock
#10
Tom Woelders, Domien G M Beersma, Marijke C M Gordijn, Roelof A Hut, Emma J Wams
Light is the most potent time cue that synchronizes (entrains) the circadian pacemaker to the 24-h solar cycle. This entrainment process is an interplay between an individual's daily light perception and intrinsic pacemaker period under free-running conditions. Establishing individual estimates of circadian phase and period can be time-consuming. We show that circadian phase can be accurately predicted (SD = 1.1 h for dim light melatonin onset, DLMO) using 9 days of ambulatory light and activity data as an input to Kronauer's limit-cycle model for the human circadian system...
April 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28444476/assessing-the-dim-light-melatonin-onset-in-adults-with-autism-spectrum-disorder-and-no-comorbid-intellectual-disability
#11
Emma K Baker, Amanda L Richdale, Agnes Hazi, Luke A Prendergast
This study assessed melatonin levels and the dim light melatonin onset (DLMO) in adults with Autism Spectrum Disorder (ASD) and also investigated the relationships between melatonin and objectively measured sleep parameters. Sixteen adults with ASD (ASD-Only), 12 adults with ASD medicated for comorbid diagnoses of anxiety and/or depression (ASD-Med) and 32 controls participated in the study. Although, the timing of the DLMO did not differ between the two groups, advances and delays of the melatonin rhythm were observed in individual profiles...
April 26, 2017: Journal of Autism and Developmental Disorders
https://www.readbyqxmd.com/read/28430415/omnidirectional-harvesting-of-weak-light-using-a-graphene-quantum-dot-modified-organic-silicon-hybrid-device
#12
Meng-Lin Tsai, Dung-Sheng Tsai, Libin Tang, Lih-Juann Chen, Shu Ping Lau, Jr-Hau He
Despite great improvements in traditional inorganic photodetectors and photovoltaics, more progress is needed in the detection/collection of light at low-level conditions. Traditional photodetectors tend to suffer from high noise when operated at room temperature; therefore, these devices require additional cooling systems to detect weak or dim light. Conventional solar cells also face the challenge of poor light-harvesting capabilities in hazy or cloudy weather. The real world features such varying levels of light, which makes it important to develop strategies that allow optical devices to function when conditions are less than optimal...
April 27, 2017: ACS Nano
https://www.readbyqxmd.com/read/28429215/effect-of-preparation-based-on-trametes-pubescens-xylotroph-fungi-on-lipid-peroxidation-in-the-blood-of-experimental-animals-under-conditions-of-dark-stress
#13
L I Kolesnikova, S I Kolesnikov, E D Romanova, V A Chkhenkeli, M A Darenskaya, L A Grebenkina, L I Korytov, O V Bugun, N V Koroleva, I N Gutnik, F F Antonenko
Using the model of dark stress caused by animal maintenance at dimmed light we showed that Trametin (product obtained during liquid-phase culturing of Trametes pubescens xylotroph fungi) effectively prevented oxidative stress under conditions of light deprivation. The preparation increased the level of unsaturation of lipids, reduced the concentration of primary and end-products of LPO, and increases both the integral parameter of the antioxidant defense system (total antioxidant activity) and its components (activity of superoxide dismutase and reduced glutathione)...
April 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28427391/fish-with-red-fluorescent-eyes-forage-more-efficiently-under-dim-blue-green-light-conditions
#14
Ulrike Katharina Harant, Nicolaas Karel Michiels
BACKGROUND: Natural red fluorescence is particularly conspicuous in the eyes of some small, benthic, predatory fishes. Fluorescence also increases in relative efficiency with increasing depth, which has generated speculation about its possible function as a "light organ" to detect cryptic organisms under bluish light. Here we investigate whether foraging success is improved under ambient conditions that make red fluorescence stand out more, using the triplefin Tripterygion delaisi as a model system...
April 20, 2017: BMC Ecology
https://www.readbyqxmd.com/read/28426025/modular-low-light-microscope-for-imaging-cellular-bioluminescence-and-radioluminescence
#15
Tae Jin Kim, Silvan Türkcan, Guillem Pratx
Low-light microscopy methods are receiving increased attention as new applications have emerged. One such application is to allow longitudinal imaging of light-sensitive cells with no phototoxicity and no photobleaching of fluorescent biomarkers. Another application is for imaging signals that are inherently dim and undetectable using standard microscopy techniques, such as bioluminescence, chemiluminescence or radioluminescence. In this protocol, we provide instructions on how to build a modular low-light microscope (1-4 d) by coupling two microscope objective lenses, back to back from each other, using standard optomechanical components...
May 2017: Nature Protocols
https://www.readbyqxmd.com/read/28425474/invasion-of-ancestral-mammals-into-dim-light-environments-inferred-from-adaptive-evolution-of-the-phototransduction-genes
#16
Yonghua Wu, Haifeng Wang, Elizabeth A Hadly
Nocturnality is a key evolutionary innovation of mammals that enables mammals to occupy relatively empty nocturnal niches. Invasion of ancestral mammals into nocturnality has long been inferred from the phylogenetic relationships of crown Mammalia, which is primarily nocturnal, and crown Reptilia, which is primarily diurnal, although molecular evidence for this is lacking. Here we used phylogenetic analyses of the vision genes involved in the phototransduction pathway to predict the diel activity patterns of ancestral mammals and reptiles...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28405608/circadian-phase-resetting-by-a-single-short-duration-light-exposure
#17
Shadab A Rahman, Melissa A St Hilaire, Anne-Marie Chang, Nayantara Santhi, Jeanne F Duffy, Richard E Kronauer, Charles A Czeisler, Steven W Lockley, Elizabeth B Klerman
BACKGROUND. In humans, a single light exposure of 12 minutes and multiple-millisecond light exposures can shift the phase of the circadian pacemaker. We investigated the response of the human circadian pacemaker to a single 15-second or 2-minute light pulse administered during the biological night. METHODS. Twenty-six healthy individuals participated in a 9-day inpatient protocol that included assessment of dim light melatonin onset time (DLMO time) before and after exposure to a single 15-second (n = 8) or 2-minute (n = 12) pulse of bright light (9,500 lux; 4,100 K fluorescent) or control background dim light (<3 lux; n = 6)...
April 6, 2017: JCI Insight
https://www.readbyqxmd.com/read/28387117/performance-characterization-of-dye-sensitized-photovoltaics-under-indoor-lighting
#18
Chia-Yuan Chen, Zih-Hong Jian, Shih-Han Huang, Kun-Mu Lee, Ming-Hsuan Kao, Chang-Hong Shen, Jia-Min Shieh, Chin-Li Wang, Chiung-Wen Chang, Bo-Zhi Lin, Ching-Yao Lin, Ting-Kuang Chang, Yun Chi, Cheng-Yu Chi, Wei-Ting Wang, Yian Tai, Ming-De Lu, Yung-Liang Tung, Po-Ting Chou, Wen-Ti Wu, Tahsin J Chow, Peter Chen, Xiang-Hao Luo, Yuh-Lang Lee, Chih-Chung Wu, Chih-Ming Chen, Chen-Yu Yeh, Miao-Syuan Fan, Jia-De Peng, Kuo-Chuan Ho, Yu-Nan Liu, Hsiao-Yi Lee, Chien-Yu Chen, Hao-Wu Lin, Chia-Te Yen, Yu-Ching Huang, Cheng-Si Tsao, Yu-Chien Ting, Tzu-Chien Wei, Chun-Guey Wu
Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE...
April 20, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28385173/novel-augmentation-strategies-in-major-depression
#19
Klaus Martiny
Hypothesis The hypotheses of all the four included studies share the common idea that it is possible to augment the effect of antidepressant drug treatment by applying different interventions and with each intervention attain a clinically meaningful better effect compared to a control condition, and with minor side effects, thus improving the short- and medium-term outcome in major depression. Procedures Study design The basic study design has been the double blind randomised controlled trial (RCT). In the light therapy study, all patients were treated with sertraline for the whole of the study duration...
April 2017: Danish Medical Journal
https://www.readbyqxmd.com/read/28381642/voltage-dependent-k-channels-improve-the-energy-efficiency-of-signalling-in-blowfly-photoreceptors
#20
Francisco J H Heras, John Anderson, Simon B Laughlin, Jeremy E Niven
Voltage-dependent conductances in many spiking neurons are tuned to reduce action potential energy consumption, so improving the energy efficiency of spike coding. However, the contribution of voltage-dependent conductances to the energy efficiency of analogue coding, by graded potentials in dendrites and non-spiking neurons, remains unclear. We investigate the contribution of voltage-dependent conductances to the energy efficiency of analogue coding by modelling blowfly R1-6 photoreceptor membrane. Two voltage-dependent delayed rectifier K(+) conductances (DRs) shape the membrane's voltage response and contribute to light adaptation...
April 2017: Journal of the Royal Society, Interface
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