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https://www.readbyqxmd.com/read/28809901/pump-linewidth-tolerant-wavelength-multicasting-using-soliton-kerr-frequency-combs
#1
Peicheng Liao, Changjing Bao, Arne Kordts, Maxim Karpov, Martin H P Pfeiffer, Lin Zhang, Yinwen Cao, Ahmed Almaiman, Amirhossein Mohajerin-Ariaei, Moshe Tur, Martin M Fejer, Tobias J Kippenberg, Alan E Willner
We experimentally demonstrate pump-linewidth-tolerant wavelength multicasting using microresonator-based soliton Kerr frequency combs. When Kerr comb lines serve as coherent pumps in a periodically poled lithium niobate waveguide, the linewidth of the multicast signal almost remains that of the original signal at different linewidths of Kerr combs, ranging from 100 kHz to 1 MHz. However, in conventional multicasting where free-running (FR) pumps are used, the linewidth of the converted signal significantly increases...
August 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28774755/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...
July 31, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28770653/simple-lighting-manipulations-facilitate-behavioral-entrainment-of-mice-to-18-h-days
#3
Thijs J Walbeek, Michael R Gorman
In an invariantly rhythmic world, a robust and stable mammalian circadian clock is presumed to confer fitness advantages. In shift-work or after rapid transmeridian travel, however, a stable clock might be maladaptive and a more flexibly resettable clock may have advantages. The rate at which rodents can adjust to simulated time zone travel and the range of entrainment can be markedly increased through simple light manipulations, namely, by exposing animals to extremely dim light (<0.01 lux) at night or by bifurcating rhythms under 24-h light-dark-light-dark (LDLD) cycles...
July 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28763478/individual-differences-in-circadian-locomotor-parameters-correlate-with-anxiety-and-depression-like-behavior
#4
Jeffrey Anyan, Michael Verwey, Shimon Amir
Disrupted circadian rhythms are a core feature of mood and anxiety disorders. Circadian rhythms are coordinated by a light-entrainable master clock located in the suprachiasmatic nucleus. Animal models of mood and anxiety disorders often exhibit blunted rhythms in locomotor activity and clock gene expression. Interestingly, the changes in circadian rhythms correlate with mood-related behaviours. Although animal models of depression and anxiety exhibit aberrant circadian rhythms in physiology and behavior, it is possible that the methodology being used to induce the behavioral phenotype (e...
2017: PloS One
https://www.readbyqxmd.com/read/28762366/prevalence-and-factors-associated-with-exercise-induced-bronchospasm-among-rural-school-children-in-ilesa-nigeria
#5
Bankole Peter Kuti, Demilade Kehinde Kuti, Kehinde Oluyori Omole, Lasisi Oluwafemi Mohammed, Busayo Gideon Ologun, Bolanle Idowu Oso
BACKGROUND: Exercise-induced bronchospasm (EIB) assessed using changes in peak expiratory flow rates (PEFRs) to free range exercise is a relatively cheap way of screening for asthma in resource-poor centres where children with asthma are often undiagnosed and poorly managed. This study sets out to determine the prevalence and factors associated with EIB among rural schoolchildren in Ilesa, Nigeria. SUBJECTS AND METHODS: Children aged 8-16 years from two middle schools in rural Ilesa were selected by multistage sampling...
April 2017: Nigerian Postgraduate Medical Journal
https://www.readbyqxmd.com/read/28687216/left-ventricular-volume-measurements-with-free-breathing-respiratory-self-gated-3-dimensional-golden-angle-radial-whole-heart-cine-imaging-feasibility-and-reproducibility
#6
Karen Holst, Martin Ugander, Andreas Sigfridsson
PURPOSE: To develop and evaluate a free breathing respiratory self-gated isotropic resolution technique for left ventricular (LV) volume measurements. METHODS: A 3D radial trajectory with double golden-angle ordering was used for free-running data acquisition during free breathing in 9 healthy volunteers. A respiratory self-gating signal was extracted from the center of k-space and used with the electrocardiogram to bin all data into 3 respiratory and 25 cardiac phases...
July 5, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28686160/the-cyanobacterial-circadian-clock-follows-midday-in-vivo-and-in-vitro
#7
Eugene Leypunskiy, Jenny Lin, Haneul Yoo, UnJin Lee, Aaron R Dinner, Michael J Rust
Circadian rhythms are biological oscillations that schedule daily changes in physiology. Outside the laboratory, circadian clocks do not generally free-run, but are driven by daily cues whose timing varies with the seasons. The principles that determine how circadian clocks align to these external cycles are not well understood. Here we report experimental platforms for driving the cyanobacterial circadian clock both in vivo and in vitro. We find that the phase of the circadian rhythm follows a simple scaling law in light-dark cycles, tracking midday across conditions with variable day length...
July 7, 2017: ELife
https://www.readbyqxmd.com/read/28663563/a-low-frequency-chip-scale-optomechanical-oscillator-with-58%C3%A2-khz-mechanical-stiffening-and-more-than-100-th-order-stable-harmonics
#8
Yongjun Huang, Jaime Gonzalo Flor Flores, Ziqiang Cai, Mingbin Yu, Dim-Lee Kwong, Guangjun Wen, Layne Churchill, Chee Wei Wong
For the sensitive high-resolution force- and field-sensing applications, the large-mass microelectromechanical system (MEMS) and optomechanical cavity have been proposed to realize the sub-aN/Hz(1/2) resolution levels. In view of the optomechanical cavity-based force- and field-sensors, the optomechanical coupling is the key parameter for achieving high sensitivity and resolution. Here we demonstrate a chip-scale optomechanical cavity with large mass which operates at ≈77.7 kHz fundamental mode and intrinsically exhibiting large optomechanical coupling of 44 GHz/nm or more, for both optical resonance modes...
June 29, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28651478/interval-timing-is-preserved-despite-circadian-desynchrony-in-rats-constant-light-and-heavy-water-studies
#9
Christian C Petersen, Ralph E Mistlberger
The mechanisms that enable mammals to time events that recur at 24-h intervals (circadian timing) and at arbitrary intervals in the seconds-to-minutes range (interval timing) are thought to be distinct at the computational and neurobiological levels. Recent evidence that disruption of circadian rhythmicity by constant light (LL) abolishes interval timing in mice challenges this assumption and suggests a critical role for circadian clocks in short interval timing. We sought to confirm and extend this finding by examining interval timing in rats in which circadian rhythmicity was disrupted by long-term exposure to LL or by chronic intake of 25% D2O...
June 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28651468/human-adolescent-phase-response-curves-to-bright-white-light
#10
Stephanie J Crowley, Charmane I Eastman
Older adolescents are particularly vulnerable to circadian misalignment and sleep restriction, primarily due to early school start times. Light can shift the circadian system and could help attenuate circadian misalignment; however, a phase response curve (PRC) to determine the optimal time for receiving light and avoiding light is not available for adolescents. We constructed light PRCs for late pubertal to postpubertal adolescents aged 14 to 17 years. Participants completed 2 counterbalanced 5-day laboratory sessions after 8 or 9 days of scheduled sleep at home...
June 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28645689/duration-and-timing-of-daily-light-exposure-influence-the-rapid-shifting-of-balb-cj-mouse-circadian-locomotor-rhythms
#11
Thomas J Vajtay, Jeremy J St Thomas, Tyrus E Takacs, Eric G McGann, E Todd Weber
Photic entrainment of the murine circadian system can typically be explained with a discrete model in which light exposures near dusk and dawn can either advance or delay free-running rhythms to match the external light cycle period. In most mouse strains, the magnitude of those phase shifts is limited to several hours per day; however, the BALB/cJ mouse can re-entrain to large (6-8hour) phase advances of the light/dark cycle. In this study, we demonstrate that the circadian responses of BALB/cJ mice are dependent on duration as well as timing of light exposure, with significantly larger phase shifts resulting from >6-hour light exposures, yet loss of entrainment to photoperiods of <2-3hours per day or to skeleton photoperiods...
June 20, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28621018/sleep-structure-in-blindness-is-influenced-by-circadian-desynchrony
#12
Sébrina Aubin, Poul Jennum, Tore Nielsen, Ron Kupers, Maurice Ptito
We examined the structure, duration and quality of sleep, including non-rapid eye movement sleep and rapid eye movement sleep, in 11 blind individuals without conscious light perception and 11 age- and sex-matched sighted controls. Because blindness is associated with a greater incidence of free-running circadian rhythms, we controlled for circadian phase by a measure of melatonin onset timing. When circadian rhythm was entrained and melatonin onset occurred at normal times, sleep structure did not differ between blind and sighted individuals...
June 16, 2017: Journal of Sleep Research
https://www.readbyqxmd.com/read/28620087/daily-activity-of-the-housefly-musca-domestica-is-influenced-by-temperature-independent-of-3-utr-period-gene-splicing
#13
Olga Bazalova, David Dolezel
Circadian clocks orchestrate daily activity patterns and free running periods of locomotor activity under constant conditions. While the first often depends on temperature, the latter is temperature-compensated over a physiologically relevant range. Here, we explored the locomotor activity of the temperate housefly Musca domestica Under low temperatures, activity was centered round a major and broad afternoon peak, while high temperatures resulted in activity throughout the photophase with a mild midday depression, which was especially pronounced in males exposed to long photoperiods...
August 7, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/28619491/the-accuracy-of-multimodality-intraoperative-neuromonitoring-to-predict-postoperative-neurological-deficits-following-cervical-laminoplasty
#14
Junichi Oya, John F Burke, Todd Vogel, Boby Tay, Dean Chou, Praveen Mummaneni
BACKGROUND: Intraoperative neuromonitoring (IONM) has been reported to be sensitive and specific in the detection of neurological injury during spinal surgery. However, utilizing multimodality IONM to predict postoperative neural deficits following cervical laminoplasty remains unclear. OBJECTIVE: The purpose of this study is to clarify the incidence of C5 palsy utilizing multimodality IONM and to compare the accuracy of multimodality IONM to predict postoperative C5 palsy against isolated transcranial motor-evoked potential (MEP)...
June 12, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28577421/season-dependent-effects-of-photoperiod-and-temperature-on-circadian-rhythm-of-arylalkylamine-n-acetyltransferase2-gene-expression-in-pineal-organ-of-an-air-breathing-catfish-clarias-gariepinus
#15
Kshetrimayum Manisana Singh, Saurav Saha, Braj Bansh Prasad Gupta
Arylalkylamine N-acetyltransferase (AANAT) activity, aanat gene expression and melatonin production have been reported to exhibit prominent circadian rhythm in the pineal organ of most species of fish. Three types of aanat genes are expressed in fish, but the fish pineal organ predominantly expresses aanat2 gene. Increase and decrease in daylength is invariably associated with increase and decrease in temperature, respectively. But so far no attempt has been made to delineate the role of photoperiod and temperature in regulation of the circadian rhythm of aanat2 gene expression in the pineal organ of any fish with special reference to seasons...
May 27, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28559360/circadian-carbon-and-light-control-of-expansion-growth-and-leaf-movement
#16
Federico Apelt, David Breuer, Justyna Jadwiga Olas, Maria Grazia Annunziata, Anna Flis, Zoran Nikoloski, Friedrich Kragler, Mark Stitt
We used Phytotyping(4D) to investigate the contribution of clock and light signaling to the diurnal regulation of rosette expansion growth and leaf movement in Arabidopsis (Arabidopsis thaliana). Wild-type plants and clock mutants with a short (lhycca1) and long (prr7prr9) period were analyzed in a T24 cycle and in T-cycles that were closer to the mutants' period. Wild types also were analyzed in various photoperiods and after transfer to free-running light or darkness. Rosette expansion and leaf movement exhibited a circadian oscillation, with superimposed transients after dawn and dusk...
July 2017: Plant Physiology
https://www.readbyqxmd.com/read/28540583/circadian-rhythm-in-melatonin-release-as-a-mechanism-to-reinforce-the-temporal-organization-of-the-circadian-system-in-crayfish
#17
Leonor Mendoza-Vargas, Armida Báez-Saldaña, Ramón Alvarado, Beatriz Fuentes-Pardo, Edgar Flores-Soto, Héctor Solís-Chagoyán
Melatonin (MEL) is a conserved molecule with respect to its synthesis pathway and functions. In crayfish, MEL content in eyestalks (Ey) increases at night under the photoperiod, and this indoleamine synchronizes the circadian rhythm of electroretinogram amplitude, which is expressed by retinas and controlled by the cerebroid ganglion (CG). The aim of this study was to determine whether MEL content in eyestalks and CG or circulating MEL in hemolymph (He) follows a circadian rhythm under a free-running condition; in addition, it was tested whether MEL might directly influence the spontaneous electrical activity of the CG...
June 2017: Invertebrate Neuroscience: IN
https://www.readbyqxmd.com/read/28536533/heart-rate-fragmentation-a-new-approach-to-the-analysis-of-cardiac-interbeat-interval-dynamics
#18
Madalena D Costa, Roger B Davis, Ary L Goldberger
Background: Short-term heart rate variability (HRV) is most commonly attributed to physiologic vagal tone modulation. However, with aging and cardiovascular disease, the emergence of high short-term HRV, consistent with the breakdown of the neuroautonomic-electrophysiologic control system, may confound traditional HRV analysis. An apparent dynamical signature of such anomalous short-term HRV is frequent changes in heart rate acceleration sign, defined here as heart rate fragmentation. Objective: The aims were to: (1) introduce a set of metrics designed to probe the degree of sinus rhythm fragmentation; (2) test the hypothesis that the degree of fragmentation of heartbeat time series increases with the participants' age in a group of healthy subjects; (3) test the hypothesis that the heartbeat time series from patients with advanced coronary artery disease (CAD) are more fragmented than those from healthy subjects; and (4) compare the performance of the new fragmentation metrics with standard time and frequency domain measures of short-term HRV...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28532908/the-safety-and-efficiency-of-pvcr-without-anterior-support-applied-in-treatment-of-yang-type-a-severe-thoracic-kyphoscoliosis
#19
Wen-Yuan Sui, Zi-Fang Huang, Yao-Long Deng, Heng-Wei Fan, Jing-Fan Yang, Fo-Bao Li, Jun-Lin Yang
OBJECTIVE: To assess the clinical and radiographic outcomes of posterior vertebral column resection (PVCR) without anterior support in treatment of Yang type A severe rigid thoracic kyphoscoliosis. METHODS: The records of 27 Yang type A severe thoracic kyphoscoliosis patients treated with PVCR without anterior support from January 2010 to September 2013 were analyzed retrospectively. Intraoperative multimodal neurophysiological monitoring was conducted in all patients...
August 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28526480/human-seasonal-and-circadian-studies-in-antarctica-halley-75-0-s
#20
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
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