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https://www.readbyqxmd.com/read/28645689/duration-and-timing-of-daily-light-exposure-influence-the-rapid-shifting-of-balb-cj-mouse-circadian-locomotor-rhythms
#1
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 <2-3h 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
#2
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
#3
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 mid-day depression, which was especially pronounced in males exposed to long photoperiods...
June 15, 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
#4
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
#5
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
#6
Federico Apelt, David Breuer, Justyna Jadwiga Olas, Maria Grazia Annunziata, Anna Flis, Zoran Nikoloski, Friedrich Kragler, Mark Stitt
We used Phytotyping4D to investigate the contribution of clock- and light-signaling to diurnal regulation of rosette expansion growth and leaf movement in Arabidopsis. 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 were also 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...
May 30, 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
#7
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
#8
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-s-a-type-severe-thoracic-kyphoscoliosis
#9
Wen-Yuan Sui, Zi-Fang Huang, Yao-Long Deng, Heng-Wei Fan, Jing-Fan Yang, Fo-Bao Li, Jun-Lin Yang
OBJECT: To assess the clinical and radiographic outcomes of posterior vertebral column resection (PVCR) without anterior support in treatment of Yang's A type severe rigid thoracic kyphoscoliosis. METHODS: The records of 27 Yang's A type severe thoracic kyphoscoliosis patients treated with PVCR without anterior support from January 2010 to September 2013 were retrospectively analyzed. Intraoperative multimodal neurophysiological monitoring (IONM) (6 modes: Somatosensory evoked potential (SSEP), Motor evoked potential (MEP), Descending neurogenic evoked potential (DNEP), Spinal cord evoked potential (SCEP), and Electromyography, both triggered and free run EMG) was conducted in all patients...
May 19, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28526480/human-seasonal-and-circadian-studies-in-antarctica-halley-75-0-s
#10
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/28504766/direct-stabilization-of-optomechanical-oscillators
#11
Ke Huang, Mani Hossein-Zadeh
We demonstrate a simple and effective technique for stabilizing the oscillation amplitude of a radiation pressure driven RF optomechanical oscillator (OMO). By controlling the optomechanical gain through a feedback loop that uses the oscillation amplitude itself as the feedback parameter, we have been able to suppress the amplitude fluctuations and drift. In contrast to more complex techniques that only lock the relative wavelength detuning, the proposed technique isolates the oscillation amplitude not only from laser wavelength variations, but also from laser power variations, ambient temperature variations, and coupling gap variations...
May 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28499924/hypercholesterolemia-causes-circadian-dysfunction-a-potential-risk-factor-for-cardiovascular-disease
#12
Makoto Akashi, Ritsuko Matsumura, Takahiro Matsuo, Yuki Kubo, Hiroshi Komoda, Koichi Node
Hypercholesterolemia is a well-known risk factor for a wide range of diseases in developed countries. Here, we report that mice lacking functional LDLR (low density lipoprotein receptor), an animal model of human familial hypercholesterolemia, show circadian abnormalities. In free running behavioral experiments in constant darkness, these mice showed a prolonged active phase and distinctly bimodal rhythms. Even when the circadian rhythms were entrained by light and dark cycles, these mice showed a significant attenuation of behavioral onset intensity at the start of the dark period...
April 27, 2017: EBioMedicine
https://www.readbyqxmd.com/read/28495879/dual-comb-spectroscopy-of-water-vapor-with-a-free-running-semiconductor-disk-laser
#13
S M Link, D J H C Maas, D Waldburger, U Keller
Dual-comb spectroscopy offers the potential for high accuracy combined with fast data acquisition. Applications are often limited, however, by the complexity of optical comb systems. Here we present dual-comb spectroscopy of water vapor using a substantially simplified single-laser system. Very good spectroscopy measurements with fast sampling rates are achieved with a free-running dual-comb mode-locked semiconductor disk laser. The absolute stability of the optical comb modes is characterized both for free-running operation and with simple microwave stabilization...
May 11, 2017: Science
https://www.readbyqxmd.com/read/28490102/effect-of-grape-juice-press-fractioning-on-polysaccharide-and-oligosaccharide-compositions-of-pinot-meunier-and-chardonnay-champagne-base-wines
#14
Sandrine Jégou, Duc An Hoang, Thomas Salmon, Pascale Williams, Solomen Oluwa, Céline Vrigneau, Thierry Doco, Richard Marchal
Press fractioning is an important step in the production of sparkling base wines to segregate the grape juices with different qualities. Grape juice fractions were collected during the pressing cycle at industrial and laboratory scales. The Pinot meunier and Chardonnay Champagne base wines obtained from the free-run juice and the squeezed juices exhibited strong differences from the beginning to the last step of pressing cycle for numerous enological parameters. Significant changes in polysaccharide (PS) and oligosaccharide (OS) base wine composition and concentration were found as the pressing cycle progressed...
October 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28461004/disruption-of-normal-circadian-clock-function-in-a-mouse-model-of-tauopathy
#15
Korey Stevanovic, Amara Yunus, Aurelie Joly-Amado, Marcia Gordon, David Morgan, Danielle Gulick, Joshua Gamsby
Disruption of normal circadian rhythm physiology is associated with neurodegenerative disease, which can lead to symptoms such as altered sleep cycles. In Alzheimer's disease (AD), circadian dysfunction has been attributed to β-amyloidosis. However, it is unclear whether tauopathy, another AD-associated neuropathology, can disrupt the circadian clock. We have evaluated the status of the circadian clock in a mouse model of tauopathy (Tg4510). Tg4510 mice display a long free-running period at an age when tauopathy is present, and show evidence of tauopathy in the suprachiasmatic nucleus (SCN) of the hypothalamus - the site of the master circadian clock...
August 2017: Experimental Neurology
https://www.readbyqxmd.com/read/28452285/daily-light-exposure-patterns-reveal-phase-and-period-of-the-human-circadian-clock
#16
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...
June 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28448626/genetic-background-dependent-effects-of-murine-micro-rnas-on-circadian-clock-function
#17
Silke Kiessling, Ahmet Ucar, Kamal Chowdhury, Henrik Oster, Gregor Eichele
MicroRNAs (miRs) are important regulators of a wide range of biological processes. Antagomir studies suggest an implication of miR-132 in the functionality of the mammalian circadian clock. miR-212 and miR-132 are tandemly processed from the same transcript and share the same seed region. We found the clock modulator miR-132 and miR-212 to be expressed rhythmically in the central circadian clock. Consequently, mRNAs implicated in circadian functions may likely be targeted by both miRs. To further characterize the circadian role we generated mice with stable deletion of the miR-132/212 locus and compared the circadian behavior of mutant and wild-type control animals on two genetic backgrounds frequently used in chronobiological research, C57BL/6N and 129/Sv...
2017: PloS One
https://www.readbyqxmd.com/read/28437981/efficient-laser-noise-reduction-method-via-actively-stabilized-optical-delay-line
#18
Dawei Li, Cheng Qian, Ye Li, Jianye Zhao
We report a fiber laser noise reduction method by locking it to an actively stabilized optical delay line, specifically a fiber-based Mach-Zehnder interferometer with a 10 km optical fiber spool. The fiber spool is used to achieve large arm imbalance. The heterodyne signal of the two arms converts the laser noise from the optical domain to several megahertz, and it is used in laser noise reduction by a phase-locked loop. An additional phase-locked loop is induced in the system to compensate the phase noise due to environmentally induced length fluctuations of the optical fiber spool...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28418264/emission-characteristics-of-laser-induced-plasma-using-collinear-long-and-short-dual-pulse-laser-induced-breakdown-spectroscopy-libs
#19
Zhenzhen Wang, Yoshihiro Deguchi, Renwei Liu, Akihiro Ikutomo, Zhenzhen Zhang, Daotong Chong, Junjie Yan, Jiping Liu, Fang-Jung Shiou
Collinear long and short dual-pulse laser-induced breakdown spectroscopy (DP-LIBS) was employed to clarify the emission characteristics from laser-induced plasma. The plasma was sustained and became stable by the long pulse-width laser with the pulse width of 60 μs under free running (FR) conditions as an external energy source. Comparing the measurement results of stainless steel in air using single-pulse LIBS (SP-LIBS) and DP-LIBS, the emission intensity was markedly enhanced using DP-LIBS. The temperature of plasma induced by DP-LIBS was maintained at a higher temperature under different gate delay time and short pulse-width laser power conditions compared with those measured using short SP-LIBS...
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28416676/dissociation-of-per1-and-bmal1-circadian-rhythms-in-the-suprachiasmatic-nucleus-in-parallel-with-behavioral-outputs
#20
Daisuke Ono, Sato Honma, Yoshihiro Nakajima, Shigeru Kuroda, Ryosuke Enoki, Ken-Ichi Honma
The temporal order of physiology and behavior in mammals is primarily regulated by the circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Taking advantage of bioluminescence reporters, we monitored the circadian rhythms of the expression of clock genes Per1 and Bmal1 in the SCN of freely moving mice and found that the rate of phase shifts induced by a single light pulse was different in the two rhythms. The Per1-luc rhythm was phase-delayed instantaneously by the light presented at the subjective evening in parallel with the activity onset of behavioral rhythm, whereas the Bmal1-ELuc rhythm was phase-delayed gradually, similar to the activity offset...
May 2, 2017: Proceedings of the National Academy of Sciences of the United States of America
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