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https://www.readbyqxmd.com/read/28229310/diagnosis-and-treatment-of-non-24-h-sleep-wake-disorder-in-the-blind
#1
REVIEW
Jonathan S Emens, Charmane I Eastman
Non-24-h sleep-wake disorder (non-24) is a circadian rhythm disorder occurring in 55-70% of totally blind individuals (those lacking conscious light perception) in which the 24-h biological clock (central, hypothalamic, circadian pacemaker) is no longer synchronized, or entrained, to the 24-h day. Instead, the overt rhythms controlled by the biological clock gradually shift progressively earlier or later (free run) in accordance with the clock's near-24-h period, resulting in a recurrent pattern of daytime hypersomnolence and night-time insomnia...
February 22, 2017: Drugs
https://www.readbyqxmd.com/read/28188883/effects-of-pinealectomy-on-the-neuroendocrine-reproductive-system-and-locomotor-activity-in-male-european-sea-bass-dicentrarchus-labrax
#2
Mairi Cowan, José A Paullada-Salmerón, José Fernando López-Olmeda, Francisco Javier Sánchez-Vázquez, José A Muñoz-Cueto
The seasonally changing photoperiod controls the timing of reproduction in most fish species, however, the transduction of this photoperiodic information to the reproductive axis is still unclear. This study explored the potential role of two candidate neuropeptide systems, gonadotropin-inhibitory hormone (Gnih) and kisspeptin, as mediators between the pineal organ (a principle transducer of photoperiodic information) and reproductive axis in male European sea bass, Dicentrarchus labrax. Two seven-day experiments of pinealectomy (Px) were performed, in March (end of reproductive season) and August (resting season)...
February 8, 2017: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
https://www.readbyqxmd.com/read/28186148/measurement-of-absolute-frequency-of-continuous-wave-terahertz-radiation-in-real-time-using-a-free-running-dual-wavelength-mode-locked-erbium-doped-fibre-laser
#3
Guoqing Hu, Tatsuya Mizuguchi, Xin Zhao, Takeo Minamikawa, Takahiko Mizuno, Yuli Yang, Cui Li, Ming Bai, Zheng Zheng, Takeshi Yasui
A single, free-running, dual-wavelength mode-locked, erbium-doped fibre laser was exploited to measure the absolute frequency of continuous-wave terahertz (CW-THz) radiation in real time using dual THz combs of photo-carriers (dual PC-THz combs). Two independent mode-locked laser beams with different wavelengths and different repetition frequencies were generated from this laser and were used to generate dual PC-THz combs having different frequency spacings in photoconductive antennae. Based on the dual PC-THz combs, the absolute frequency of CW-THz radiation was determined with a relative precision of 1...
February 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28162920/how-does-general-anaesthesia-affect-the-circadian-clock
#4
REVIEW
Raewyn C Poulsen, Guy R Warman, Jamie Sleigh, Nicola M Ludin, James F Cheeseman
: Post-operative patients experience sleep disturbances. Animal studies demonstrate that general anaesthesia (GA) can disrupt circadian rhythms and cause changes in the molecular clock, indicating that anaesthesia contributes to post-operative circadian disruption. Here we review the effect of anaesthesia on the circadian clock and its rhythms in order to summarise current findings outline commonalities between studies and propose mechanisms by which effects may be mediated. KEY POINTS: 1) GA has strong effects on the main neurotransmitter systems linked with circadian control (Gamma aminobutyric acid/N-methyl-D-aspartate (GABA/NMDA)) and may act by interfering with light-entrainment of the clock...
December 18, 2016: Sleep Medicine Reviews
https://www.readbyqxmd.com/read/28158098/simultaneous-dual-wavelength-q-switched-nd-yag-laser-at-1052-and-1073%C3%A2-%C3%A2-nm
#5
Haifeng Lin, Wenzhang Zhu, Feibing Xiong, Jianjian Ruan
We report a continuous-wave dual-wavelength Nd:YAG laser at 1052 and 1073 nm, for the first time to the best of our knowledge, in free-running mode. The maximum output power reaches 6.64 W with slope efficiency of about 42.1% with respect to the absorbed power. Inserting a Cr:YAG saturable absorber, the dual-wavelength laser can operate in the Q-switching regime with maximum average output power of 880 mW. The minimum pulse width and the highest pulse repetition rate are 28 ns and 17.12 kHz, respectively. The dual-wavelength laser has potential to generate a 5...
February 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/28156168/evolution-of-circadian-rhythms-in-drosophila-melanogaster-populations-reared-in-constant-light-and-dark-regimes-for-over-330-generations
#6
Radhika Shindey, Vishwanath Varma, K L Nikhil, Vijay Kumar Sharma
Organisms are believed to have evolved circadian clocks as adaptations to deal with cyclic environmental changes, and therefore it has been hypothesized that evolution in constant environments would lead to regression of such clocks. However, previous studies have yielded mixed results, and evolution of circadian clocks under constant conditions has remained an unsettled topic of debate in circadian biology. In continuation of our previous studies, which reported persistence of circadian rhythms in Drosophila melanogaster populations evolving under constant light, here we intended to examine whether circadian clocks and the associated properties evolve differently under constant light and constant darkness...
February 3, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28120082/intraoperative-neurophysiological-monitoring-in-spine-surgery-a-significant-tool-for-neuronal-protection-and-functional-restoration
#7
Antonino Scibilia, Giovanni Raffa, Vincenzo Rizzo, Angelo Quartarone, Massimiliano Visocchi, Antonino Germanò, Francesco Tomasello
Although there is recent evidence for the role of intraoperative neurophysiological monitoring (IONM) in spine surgery, there are no uniform opinions on the optimal combination of the different tools. At our institution, multimodal IONM (mIONM) approach in spine surgery involves the evaluation of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) with electrical transcranial stimulation, including the use of a multipulse technique with multiple myomeric registration of responses from limbs, and a single-pulse technique with D-wave registration through epi- and intradural recording, and free running and evoked electromyography (frEMG and eEMG) with bilateral recording from segmental target muscles...
2017: Acta Neurochirurgica. Supplement
https://www.readbyqxmd.com/read/28059397/accurate-frequency-referencing-for-fieldable-dual-comb-spectroscopy
#8
Gar-Wing Truong, Eleanor M Waxman, Kevin C Cossel, Esther Baumann, Andrew Klose, Fabrizio R Giorgetta, William C Swann, Nathan R Newbury, Ian Coddington
We describe a dual-comb spectrometer that can operate independently of laboratory-based rf and optical frequency references but is nevertheless capable of ultra-high spectral resolution, high SNR, and frequency-accurate spectral measurements. The instrument is based on a "bootstrapped" frequency referencing scheme in which short-term optical phase coherence between combs is attained by referencing each to a free-running diode laser, whilst high frequency resolution and long-term accuracy is derived from a stable quartz oscillator...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28034638/free-breathing-whole-heart-3d-cine-mri-with-self-gated-cartesian-trajectory
#9
M Usman, B Ruijsink, M S Nazir, G Cruz, C Prieto
PURPOSE: To present a method that uses a novel free-running self-gated acquisition to achieve isotropic resolution in whole heart 3D Cartesian cardiac CINE MRI. MATERIAL AND METHODS: 3D cardiac CINE MRI using navigator gating results in long acquisition times. Recently, several frameworks based on self-gated non-Cartesian trajectories have been proposed to accelerate this acquisition. However, non-Cartesian reconstructions are computationally expensive due to gridding, particularly in 3D...
December 26, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27997028/differential-sensitivity-to-ethanol-induced-circadian-rhythm-disruption-in-adolescent-and-adult-mice
#10
Christina L Ruby, Kaitlyn N Palmer, Jiawen Zhang, Megan O Risinger, Melissa A Butkowski, H Scott Swartzwelder
BACKGROUND: Growing evidence supports a central role for the circadian system in alcohol use disorders, but few studies have examined this relationship during adolescence. In mammals, circadian rhythms are regulated by the suprachiasmatic nucleus, a biological clock whose timing is synchronized (reset) to the environment primarily by light (photic) input. Alcohol (ethanol [EtOH]) disrupts circadian timing in part by attenuating photic phase-resetting responses in adult rodents. However, circadian rhythms change throughout life and it is not yet known whether EtOH has similar effects on circadian regulation during adolescence...
January 2017: Alcoholism, Clinical and Experimental Research
https://www.readbyqxmd.com/read/27974202/the-drosophila-clock-neuron-network-features-diverse-coupling-modes-and-requires-network-wide-coherence-for-robust-circadian-rhythms
#11
Zepeng Yao, Amelia J Bennett, Jenna L Clem, Orie T Shafer
In animals, networks of clock neurons containing molecular clocks orchestrate daily rhythms in physiology and behavior. However, how various types of clock neurons communicate and coordinate with one another to produce coherent circadian rhythms is not well understood. Here, we investigate clock neuron coupling in the brain of Drosophila and demonstrate that the fly's various groups of clock neurons display unique and complex coupling relationships to core pacemaker neurons. Furthermore, we find that coordinated free-running rhythms require molecular clock synchrony not only within the well-characterized lateral clock neuron classes but also between lateral clock neurons and dorsal clock neurons...
December 13, 2016: Cell Reports
https://www.readbyqxmd.com/read/27973517/temporal-jitter-in-free-running-ingaas-inp-single-photon-avalanche-detectors
#12
Emna Amri, Gianluca Boso, Boris Korzh, Hugo Zbinden
Negative-feedback avalanche diodes (NFADs) provide a practical solution for different single-photon counting applications requiring free-running mode operation with low afterpulsing probability. Unfortunately, the timing jitter has never been as good as for gated InGaAs/InP single-photon avalanche diodes. Here we report on the timing jitter characterization of InGaAs/InP based NFADs with particular focus on the temperature dependence and the effect of carrier transport between the absorption and multiplication regions...
December 15, 2016: Optics Letters
https://www.readbyqxmd.com/read/27973516/amplification-of-a-nanosecond-laser-pulse-chain-via-dynamic-injection-locking-of-a-laser-diode
#13
Jun He, Gang Jin, Bei Liu, Junmin Wang
We report a novel optical pulse generation method for high-speed wavelength switching of amplified nanosecond (ns) laser pulses resonant to atomic transitions. Under free-running conditions, a slave laser diode is blue-detuned with tens of GHz relative to the master laser. A nanosecond pulse chain generated by modulating the continuous-wave master laser with a fiber-pigtailed electro-optical intensity modulator is injected into the slave laser diode to fast switch the slave laser's wavelength back and forth...
December 15, 2016: Optics Letters
https://www.readbyqxmd.com/read/27910521/a-low-temperature-external-cavity-diode-laser-for-broad-wavelength-tuning
#14
William G Tobias, Jason S Rosenberg, Nicholas R Hutzler, Kang-Kuen Ni
We report on the design and characterization of a low-temperature external cavity diode laser (ECDL) system for broad wavelength tuning. The performance achieved with multiple diode models addresses the scarcity of commercial red laser diodes below 633 nm, which is a wavelength range relevant to the spectroscopy of many molecules and ions. Using a combination of multiple-stage thermoelectric cooling and water cooling, the operating temperature of a laser diode is lowered to -64 °C, more than 85 °C below the ambient temperature...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27906312/widely-tunable-narrow-linewidth-external-cavity-gain-chip-laser-for-spectroscopy-between-1-0-1-1-%C3%A2%C2%B5m
#15
Dong K Shin, Bryce M Henson, Roman I Khakimov, Jacob A Ross, Colin J Dedman, Sean S Hodgman, Kenneth G H Baldwin, Andrew G Truscott
We have developed and characterised a stable, narrow linewidth external-cavity laser (ECL) tunable over 100 nm around 1080 nm, using a single-angled-facet gain chip. We propose the ECL as a low-cost, high-performance alternative to fibre and diode lasers in this wavelength range and demonstrate its capability through the spectroscopy of metastable helium. Within the coarse tuning range, the wavelength can be continuously tuned over 30 pm (7.8 GHz) without mode-hopping and modulated with bandwidths up to 3 kHz (piezo) and 37(3) kHz (current)...
November 28, 2016: Optics Express
https://www.readbyqxmd.com/read/27906238/microresonator-stabilized-2%C3%A2-%C3%A2-%C3%AE-m-distributed-feedback-gasb-based-diode-laser
#16
Elijah Dale, Mahmood Bagheri, Andrey B Matsko, Clifford Frez, Wei Liang, Siamak Forouhar, Lute Maleki
We report on the stabilization of a high-power distributed feedback (DFB) semiconductor laser operating at 2.05 μm wavelength, using a crystalline whispering gallery mode microresonator. The laser's frequency noise is measured to be below 100  Hz/Hz<sup>1/2</sup> at Fourier frequencies ranging from 10 Hz to 1 MHz. The instantaneous linewidth of the laser is improved by four orders of magnitude compared with the free-running DFB laser, and is measured to be 15 Hz at 0.1 ms measurement time...
December 1, 2016: Optics Letters
https://www.readbyqxmd.com/read/27869838/analytical-comparison-of-pulses-generated-by-locking-three-and-five-longitudinal-modes-in-free-running-class-b-lasers
#17
Farzane Sharafi, Jafar Jahanpanah
We consider the coherent oscillation of five longitudinal modes, which leads to the coupling of modes in the frequency domain and generation of short pulses in the time domain. The aim is to audit the mechanism of mode locking in more detail by extending the analytical solution of the Maxwell-Bloch equations of motion from three to five mode states. The characteristics of pulses including height, repetition, and duration have been calculated for a five-mode class B laser, and the changes are compared with respect to the three-mode state...
November 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/27869182/the-effects-of-non-self-sustained-oscillators-on-the-en-trainment-ability-of-the-suprachiasmatic-nucleus
#18
Changgui Gu, Ming Tang, Jos H T Rohling, Huijie Yang
In mammals, the circadian rhythms of behavioral and physiological activities are regulated by an endogenous clock located in the suprachiasmatic nucleus (SCN). The SCN is composed of ~20,000 neurons, of which some are capable of self-sustained oscillations, while the others do not oscillate in a self-sustainable manner, but show arrhythmic patterns or damped oscillations. Thus far, the effects of these non-self-sustained oscillatory neurons are not fully explored. Here, we examined how the proportion of the non-self-sustained oscillators affects the free running period under constant darkness and the ability to entrain to the light-dark cycle...
November 21, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27830946/seven-day-human-biological-rhythms-an-expedition-in-search-of-their-origin-synchronization-functional-advantage-adaptive-value-and-clinical-relevance
#19
Alain E Reinberg, Laurence Dejardin, Michael H Smolensky, Yvan Touitou
This fact-finding expedition explores the perspectives and knowledge of the origin and functional relevance of the 7 d domain of the biological time structure, with special reference to human beings. These biological rhythms are displayed at various levels of organization in diverse species - from the unicellular sea algae of Acetabularia and Goniaulax to plants, insects, fish, birds and mammals, including man - under natural as well as artificial, i.e. constant, environmental conditions. Nonetheless, very little is known about their derivation, functional advantage, adaptive value, synchronization and potential clinical relevance...
2017: Chronobiology International
https://www.readbyqxmd.com/read/27828388/time-domain-modeling-of-terahertz-quantum-cascade-lasers-for-frequency-comb-generation
#20
Petar Tzenov, David Burghoff, Qing Hu, Christian Jirauschek
The generation of frequency combs in the mid-infrared and terahertz regimes from compact and potentially cheap sources could have a strong impact on spectroscopy, as many molecules have their rotovibrational bands in this spectral range. Thus, quantum cascade lasers (QCLs) are the perfect candidates for comb generation in these portions of the electromagnetic spectrum. Here we present a theoretical model based on a full numerical solution of Maxwell-Bloch equations suitable for the simulation of such devices...
October 3, 2016: Optics Express
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