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https://www.readbyqxmd.com/read/28448626/genetic-background-dependent-effects-of-murine-micro-rnas-on-circadian-clock-function
#1
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
#2
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
#3
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
#4
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...
April 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28415286/dissociation-between-two-subgroups-of-the-suprachiasmatic-nucleus-affected-by-the-number-of-damped-oscillated-neurons
#5
Changgui Gu, Huijie Yang, Jos Ht Rohling
In mammals, the main clock located in the suprachiasmatic nucleus (SCN) of the brain synchronizes the body rhythms to the environmental light-dark cycle. The SCN is composed of about 2×10^{4} neurons which can be classified into three oscillatory phenotypes: self-sustained oscillators, damped oscillators, and arrhythmic neurons. Exposed to an artificial external light-dark cycle with a period of 22h instead of 24h, two subgroups of the SCN can become desynchronized (dissociated). The ventrolateral (VL) subgroup receives photic input and is entrained to the external cycle and a dorsomedial (DM) subgroup oscillates with its endogenous (i...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28382017/disrupted-ultradian-activity-rhythms-and-differential-expression-of-several-clock-genes-in-interleukin-6-deficient-mice
#6
Francisco J Monje, Ana Cicvaric, Juan Pablo Acevedo Aguilar, Immanuel Elbau, Orsolya Horvath, Weifei Diao, Micaela Glat, Daniela D Pollak
The characteristics of the cycles of activity and rest stand out among the most intensively investigated aspects of circadian rhythmicity in humans and experimental animals. Alterations in the circadian patterns of activity and rest are strongly linked to cognitive and emotional dysfunctions in severe mental illnesses such as Alzheimer's disease (AD) and major depression (MDD). The proinflammatory cytokine interleukin 6 (IL-6) has been prominently associated with the pathogenesis of AD and MDD. However, the potential involvement of IL-6 in the modulation of the diurnal rhythms of activity and rest has not been investigated...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28380932/self-corrected-chip-based-dual-comb-spectrometer
#7
Nicolas Bourbeau Hébert, Jérôme Genest, Jean-Daniel Deschênes, Hugo Bergeron, George Y Chen, Champak Khurmi, David G Lancaster
We present a dual-comb spectrometer based on two passively mode-locked waveguide lasers integrated in a single Er-doped ZBLAN chip. This original design yields two free-running frequency combs having a high level of mutual stability. We developed in parallel a self-correction algorithm that compensates residual relative fluctuations and yields mode-resolved spectra without the help of any reference laser or control system. Fluctuations are extracted directly from the interferograms using the concept of ambiguity function, which leads to a significant simplification of the instrument that will greatly ease its widespread adoption and commercial deployment...
April 3, 2017: Optics Express
https://www.readbyqxmd.com/read/28380828/performance-and-wavelength-tuning-of-green-emitting-terbium-lasers
#8
Philip Werner Metz, Daniel-Timo Marzahl, Günter Huber, Christian Kränkel
Wavelength tuning experiments in the green spectral range applying Tb<sup>3+</sup>-doped LiLuF<sub>4</sub> and Tb<sup>3+</sup>/Na<sup>+</sup>-codoped CaF<sub>2</sub> single crystals are presented. While in the former case almost 100 mW could be obtained throughout a total range of 7 nm, the inhomogeneously broadened emission features of Tb<sup>3+</sup> in the CaF<sub>2</sub>-matrix allowed for a continuous tuning range exceeding 10 nm...
March 6, 2017: Optics Express
https://www.readbyqxmd.com/read/28332253/sex-and-ancestry-determine-the-free-running-circadian-period
#9
Charmane I Eastman, Victoria A Tomaka, Stephanie J Crowley
The endogenous, free-running circadian period (τ) determines the phase relationship that an organism assumes when entrained to the 24-h day. We found a shorter circadian period in African Americans compared to non-Hispanic European Americans (24.07 versus 24.33 h). We speculate that a short circadian period, closer to 24 h, was advantageous to humans living around the equator, but when humans migrated North out of Africa, where the photoperiod changes with seasons, natural selection favoured people with longer circadian periods...
March 23, 2017: Journal of Sleep Research
https://www.readbyqxmd.com/read/28331201/synchrony-of-plant-cellular-circadian-clocks-with-heterogeneous-properties-under-light-dark-cycles
#10
Masaaki Okada, Tomoaki Muranaka, Shogo Ito, Tokitaka Oyama
Individual cells in a plant can work independently as circadian clocks, and their properties are the basis of various circadian phenomena. The behaviour of individual cellular clocks in Lemna gibba was orderly under 24-h light/dark cycles despite their heterogeneous free-running periods (FRPs). Here, we reveal the entrainment habits of heterogeneous cellular clocks using non-24-h light/dark cycles (T-cycles). The cellular rhythms of AtCCA1::LUC under T = 16 h cycles showed heterogeneous entrainment that was associated with their heterogeneous FRPs...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28297889/time-varying-coupling-functions-dynamical-inference-and-cause-of-synchronization-transitions
#11
Tomislav Stankovski
Interactions in nature can be described by their coupling strength, direction of coupling, and coupling function. The coupling strength and directionality are relatively well understood and studied, at least for two interacting systems; however, there can be a complexity in the interactions uniquely dependent on the coupling functions. Such a special case is studied here: synchronization transition occurs only due to the time variability of the coupling functions, while the net coupling strength is constant throughout the observation time...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28295094/excess-carrier-envelope-phase-noise-generation-in-saturable-absorbers
#12
Nils Raabe, Tianli Feng, Mark Mero, Haochen Tian, Youjian Song, Wolfgang Hänsel, Ronald Holzwarth, Alexander Sell, Armin Zach, Günter Steinmeyer
Attosecond spectroscopy and precision frequency metrology depend on the stabilization of the carrier-envelope phase (CEP) of mode-locked lasers. Unfortunately, the phase of only a few types of lasers can be stabilized to jitters in the few-hundred millirad range. In a comparative experimental study, we analyze a femtosecond Ti:sapphire laser and three mode-locked fiber lasers. We numerically demodulate recorded time series of the free-running carrier-envelope beat note. Our analysis indicates a correlation between amplitude and frequency fluctuations at low Fourier frequencies for essentially all lasers investigated...
March 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28271169/-intraoperative-monitoring-of-the-facial-nerve-vestibular-schwannoma-surgery
#13
J Prell, C Strauss, S K Plontke, S Rampp
BACKGROUND: In vestibular schwannoma surgery, facial nerve injury with consecutive functional impairment is one of the most important complications. Intraoperative monitoring of facial nerve function has been developed in order to avoid this complication. OBJECTIVE: Which methods for intraoperative monitoring have been developed? Which methods are in use today and what can they achieve in modern vestibular schwannoma surgery? MATERIAL AND METHODS: This article provides an evaluation and summary of the literature, as well as a discussion of the methods and their ability to achieve the goals of intraoperative monitoring...
March 7, 2017: HNO
https://www.readbyqxmd.com/read/28241613/regrowth-free-integration-of-injection-locked-slotted-laser-with-an-electroabsorption-modulator
#14
Niall P Kelly, Ludovic Caro, Mohamad Dernaika, Frank H Peters
Optical injection locking was used to red shift an integrated semiconductor laser up to 30 nm away from the main free running lasing mode. This injection locking of the laser beyond its band edge enabled its integration with an electroabsorption modulator to produce a 2.5 Gb/s eye diagram. The electroabsorption modulator was shown to have a 3 dB bandwidth of 5.5 GHz, which was limited by the contact capacitance. This paper demonstrates that such devices could be applied in a regrowth free, monolithic coherent wavelength division multiplexing transmitter...
February 20, 2017: Optics Express
https://www.readbyqxmd.com/read/28229310/diagnosis-and-treatment-of-non-24-h-sleep-wake-disorder-in-the-blind
#15
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...
April 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
#16
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
#17
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
#18
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
#19
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
#20
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...
2017: Chronobiology International
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