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Xi He, Shanshan Song, Ramon J Ayon, Angela Balisterieri, Stephen M Black, Ayako Makino, W Gil Wier, Wei-Jin Zang, Jason X-J Yuan
Ca2+ signaling, particularly the mechanism via store-operated Ca2+ entry (SOCE) and receptor-operated Ca2+ entry (ROCE), plays a critical role in the development of acute hypoxia-induced pulmonary vasoconstriction and chronic hypoxia-induced pulmonary hypertension. This study aimed to test the hypothesis that chronic hypoxia differentially regulates the expression of proteins that mediate SOCE and ROCE (STIM, Orai, and TRPC6) in pulmonary (PASMC) and coronary (CASMC) artery smooth muscle cells. The resting cytosolic [Ca2+] ([Ca2+]cyt) and the stored [Ca2+] in the sarcoplasmic reticulum (SR) were not different in CASMC and PASMC...
January 3, 2018: American Journal of Physiology. Cell Physiology
Xiaoying Zhou, Bin Wang, Jillian M Emerson, Carol S Ringelberg, Scott A Gerber, Jennifer J Loros, Jay C Dunlap
Circadian clocks are ubiquitous in eukaryotic organisms where they are used to anticipate regularly occurring diurnal and seasonal environmental changes. Nevertheless, little is known regarding pathways connecting the core clock to its output pathways. Here, we report that the HAD family phosphatase CSP-6 is required for overt circadian clock output but not for the core oscillation. The loss of function Δcsp-6 deletion mutant is overtly arrhythmic on race tubes under free running conditions; however, reporter assays confirm that the FREQUENCY-WHITE COLLAR COMPLEX core circadian oscillator is functional, indicating a discrete block between oscillator and output...
January 19, 2018: PLoS Genetics
Stefan Stevanovic, Boris Pervan
We propose a novel GPS phase-lock loop (PLL) performance metric based on the standard deviation of tracking error (defined as the discriminator's estimate of the true phase error), and explain its advantages over the popular phase jitter metric using theory, numerical simulation, and experimental results. We derive an augmented GPS phase-lock loop (PLL) linear model, which includes the effect of coherent averaging, to be used in conjunction with this proposed metric. The augmented linear model allows more accurate calculation of tracking error standard deviation in the presence of additive white Gaussian noise (AWGN) as compared to traditional linear models...
January 19, 2018: Sensors
Enrico Pirotta, Marc Mangel, Daniel P Costa, Bruce Mate, Jeremy A Goldbogen, Daniel M Palacios, Luis A Hückstädt, Elizabeth A McHuron, Lisa Schwarz, Leslie New
Integrating behavior and physiology is critical to formulating new hypotheses on the evolution of animal life-history strategies. Migratory capital breeders acquire most of the energy they need to sustain migration, gestation, and lactation before parturition. Therefore, when predicting the impact of environmental variation on such species, a mechanistic understanding of the physiology of their migratory behavior is required. Using baleen whales as a model system, we developed a dynamic state variable model that captures the interplay among behavioral decisions, energy, reproductive needs, and the environment...
February 2018: American Naturalist
Jonathan Kohler, Justin A Gerber, Emma Dowd, Dan M Stamper-Kurn
We realize a spin-orbit interaction between the collective spin precession and center-of-mass motion of a trapped ultracold atomic gas, mediated by spin- and position-dependent dispersive coupling to a driven optical cavity. The collective spin, precessing near its highest-energy state in an applied magnetic field, can be approximated as a negative-mass harmonic oscillator. When the Larmor precession and mechanical motion are nearly resonant, cavity mediated coupling leads to a negative-mass instability, driving exponential growth of a correlated mode of the hybrid system...
January 5, 2018: Physical Review Letters
Janni Lisander Larsen, Elisabeth O C Hall, Søren Jacobsen, Regner Birkelund
AIM: To explore, from the perspective of women the nature of basic existential conditions while living with systemic lupus erythematosus. BACKGROUND: Systemic lupus erythematosus has an unpredictable disease course and is documented to cause an existential rearrangement of life. The significance of changes in existential conditions and related experiences are unclear in the context of nursing and women with systemic lupus erythematosus. DESIGN: A qualitative design guided by Van Manen's hermeneutic phenomenological methodology...
January 19, 2018: Journal of Advanced Nursing
Zhizhao Che, Omar K Matar
The impact of droplets on liquid films is a ubiquitous phenomenon not only in nature but also in many industrial applications. Compared to the widely-studied impact of droplets on films of identical fluids, the impact of droplets on immiscible films has received far less attention. In the present work, we show using high-speed imaging that immiscibility has a profound effect on the impact dynamics. The impact of a water droplet on an oil film leads to the formation of a compound crown followed by a central jet, whereas that of an oil droplet on a water film results in rapid spreading on the film surface driven by a large, positive spreading factor...
January 19, 2018: Soft Matter
Niall D Ferguson, Claude Guérin
No abstract text is available yet for this article.
January 18, 2018: Intensive Care Medicine
Matthew T Dickerson, Avery M Bogart, Molly K Altman, Sarah C Milian, Kelli L Jordan, Prasanna K Dadi, David A Jacobson
Cytokines present during low-grade inflammation contribute to β-cell dysfunction and diabetes. Cytokine signaling disrupts β-cell glucose-stimulated Ca2+ influx (GSCI) and endoplasmic reticulum (ER) Ca2+ ([Ca2+]ER) handling, leading to diminished glucose-stimulated insulin secretion (GSIS). However, cytokine-mediated changes in ion channel activity that alter β-cell Ca2+ handling remain unknown. Here we investigated the role of K+ currents in cytokine-mediated β-cell dysfunction. Kslow currents, which control the termination of intracellular Ca2+ ([Ca2+]i) oscillations, were reduced following cytokine exposure...
January 18, 2018: Scientific Reports
Mustafa Mert Torunbalci, Tanay Arun Gosavi, Kerem Yunus Camsari, Sunil Ashok Bhave
This paper introduces a novel oscillator that combines the tunability of spin Hall-driven nano oscillators with the high quality factor (Q) of high overtone bulk acoustic wave resonators (HBAR), integrating both reference and tunable oscillators on the same chip with CMOS. In such magneto acoustic spin Hall (MASH) oscillators, voltage oscillations across the magnetic tunnel junction (MTJ) that arise from a spin-orbit torque (SOT) are shaped by the transmission response of the HBAR that acts as a multiple peak-bandpass filter and a delay element due to its large time constant, providing delayed feedback...
January 18, 2018: Scientific Reports
Clarissa Martinez-Rubio, Angelique C Paulk, Eric J McDonald, Alik S Widge, Emad N Eskandar
Associative learning is crucial for daily function, involving a complex network of brain regions. One region, the nucleus basalis of Meynert (NBM), is a highly interconnected, largely cholinergic structure implicated in multiple aspects of learning. We show that single neurons in the NBM of non-human primates (NHPs; N=2 males; Macaca mulatta) encode learning a new association through spike rate modulation. Yet, the power of low-frequency local field potential (LFP) oscillations decreases in response to novel, not-yet-learned stimuli but then increase as learning progresses...
January 18, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
H Lv, Z Wang, E Tong, L M Williams, G Zaharchuk, M Zeineh, A N Goldstein-Piekarski, T M Ball, C Liao, M Wintermark
Resting-state fMRI was first described by Biswal et al in 1995 and has since then been widely used in both healthy subjects and patients with various neurologic, neurosurgical, and psychiatric disorders. As opposed to paradigm- or task-based functional MR imaging, resting-state fMRI does not require subjects to perform any specific task. The low-frequency oscillations of the resting-state fMRI signal have been shown to relate to the spontaneous neural activity. There are many ways to analyze resting-state fMRI data...
January 18, 2018: AJNR. American Journal of Neuroradiology
Jose M Esnaola-Acebes, Alex Roxin, Daniele Avitabile, Ernest Montbrió
We investigate the modes of oscillation of heterogeneous ring networks of quadratic integrate-and-fire (QIF) neurons with nonlocal, space-dependent coupling. Perturbations of the equilibrium state with a particular wave number produce transient standing waves with a specific temporal frequency, analogously to those in a tense string. In the neuronal network, the equilibrium corresponds to a spatially homogeneous, asynchronous state. Perturbations of this state excite the network's oscillatory modes, which reflect the interplay of episodes of synchronous spiking with the excitatory-inhibitory spatial interactions...
November 2017: Physical Review. E
Changgui Gu, Huijie Yang, Man Wang
Living beings on the Earth are subjected to and entrained (synchronized) to the natural 24-h light-dark cycle. Interestingly, they can also be entrained to an external artificial cycle of non-24-h periods. The range of these periods is called the entrainment range and it differs among species. In mammals, the entrainment range is regulated by a main clock located in the suprachiasmatic nucleus (SCN) which is composed of 10 000 neurons in the brain. Previous works have found that the entrainment range depends on the cellular coupling strength in the SCN...
November 2017: Physical Review. E
Yizhou Tan, Jannes Gladrow, Ulrich F Keyser, Leonardo Dagdug, Stefano Pagliara
Membrane protein transporters alternate their substrate-binding sites between the extracellular and cytosolic side of the membrane according to the alternating access mechanism. Inspired by this intriguing mechanism devised by nature, we study particle transport through a channel coupled with an energy well that oscillates its position between the two entrances of the channel. We optimize particle transport across the channel by adjusting the oscillation frequency. At the optimal oscillation frequency, the translocation rate through the channel is a hundred times higher with respect to free diffusion across the channel...
November 2017: Physical Review. E
Sebastian Eydam, Matthias Wolfrum
We investigate the dynamics of a Kuramoto-type system of globally coupled phase oscillators with equidistant natural frequencies and a coupling strength below the synchronization threshold. It turns out that in such cases one can observe a stable regime of sharp pulses in the mean field amplitude with a pulsation frequency given by spacing of the natural frequencies. This resembles a process known as mode locking in lasers and relies on the emergence of a phase relation induced by the nonlinear coupling. We discuss the role of the first and second harmonics in the phase-interaction function for the stability of the pulsations and present various bifurcating dynamical regimes such as periodically and chaotically modulated mode locking, transitions to phase turbulence, and intermittency...
November 2017: Physical Review. E
Changhai Tian, Hongjie Bi, Xiyun Zhang, Shuguang Guan, Zonghua Liu
Chimera state has been well studied recently, but little attention has been paid to its transition to synchronization. We study this topic here by considering two groups of adaptively coupled Kuramoto oscillators. By searching the final states of different initial conditions, we find that the system can easily show a chimera state with robustness to initial conditions, in contrast to the sensitive dependence of chimera state on initial conditions in previous studies. Further, we show that, in the case of symmetric couplings, the behaviors of the two groups are always complementary to each other, i...
November 2017: Physical Review. E
Sergey Makovkin, Anil Kumar, Alexey Zaikin, Sarika Jalan, Mikhail Ivanchenko
Inspired by the recent interest in collective dynamics of biological neural networks immersed in the glial cell medium, we investigate the frequency and phase order, i.e., Kuramoto type of synchronization in a multiplex two-layer network of phase oscillators of different time scales and topologies. One of them has a long-range connectivity, exemplified by the Erdős-Rényi random network, and supports both kinds of synchrony. The other is a locally coupled two-dimensional lattice that can reach frequency synchronization but lacks phase order...
November 2017: Physical Review. E
Nathan Perchikov, O V Gendelman
Local configurational symmetry in lattice structures may give rise to stationary, compact solutions, even in the absence of disorder and nonlinearity. These compact solutions are related to the existence of flat dispersion curves (bands). Nonlinearity can destabilize such compactons. One common flat-band-generating system is the one-dimensional cross-stitch model, in which compactons were shown to exist for the photonic lattice with Kerr nonlinearity. The compactons exist there already in the linear regime and are not generally destructed by that nonlinearity...
November 2017: Physical Review. E
Shuvojit Paul, Abhrajit Laskar, Rajesh Singh, Basudev Roy, R Adhikari, Ayan Banerjee
The fluctuation-dissipation relation, a central result in nonequilibrium statistical physics, relates equilibrium fluctuations in a system to its linear response to external forces. Here we provide a direct experimental verification of this relation for viscously coupled oscillators, as realized by a pair of optically trapped colloidal particles. A theoretical analysis, in which interactions mediated by slow viscous flow are represented by nonlocal friction tensors, matches experimental results and reveals a frequency maximum in the amplitude of the mutual response which is a sensitive function of the trap stiffnesses and the friction tensors...
November 2017: Physical Review. E
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