11,114 research outputs found

    Algorithm for Monitoring Head/Eye Motion for Driver Alertness with one Camera

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    Visual methods and systems are described for detecting alterness and vigilance of persons under the conditions of fatigue, lack of sleep, and exposure to mind altering substances such as alcohol or drugs. In particular, the invention can have particular application for truck drivers, bus drivers, train operators, pilots and watercraft controllers and stationary heavy equipment operators, and students and employees during either daytime or nighttime conditions. The invention robustly tracks a person\u27s head and facial features with a single on-board camera with a fully automatic system, that can intitalize automatically, and can reinitialize when it needs to and provide outputs in realtime. The system can classify rotation in all viewing directions, detects eye/mouth occlusion, detects eye blinking, and recovers the 3D (three dimensional) gaze of the eyes. In addition, the system is able to track both through occlusion like eye blinking and through occlusion like rotation. Outputs can be visual and sound alarms to the driver directly..

    Bitter taste receptor agonists alter mitochondrial function and induce autophagy in airway smooth muscle cells

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    © 2017 the American Physiological Society. Airway remodeling, including increased airway smooth muscle (ASM) mass, is a hallmark feature of asthma and COPD. We previously identified the expression of bitter taste receptors (TAS2Rs) on human ASM cells and demonstrated that known TAS2R agonists could promote ASM relaxation and bronchodilation and inhibit mitogen-induced ASM growth. In this study, we explored cellular mechanisms mediating the antimitogenic effect of TAS2R agonists on human ASM cells. Pretreatment of ASM cells with TAS2R agonists chloroquine and quinine resulted in inhibition of cell survival, which was largely reversed by bafilomycin A1, an autophagy inhibitor. Transmission electron microscope studies demonstrated the presence of double-membrane autophagosomes and deformed mitochondria. In ASM cells, TAS2R agonists decreased mitochondrial membrane potential and increased mitochondrial ROS and mitochondrial fragmentation. Inhibiting dynamin-like protein 1 (DLP1) reversed TAS2R agonist-induced mitochondrial membrane potential change and attenuated mitochondrial fragmentation and cell death. Furthermore, the expression of mitochondrial protein BCL2/ adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) and mitochondrial localization of DLP1 were significantly upregulated by TAS2R agonists. More importantly, inhibiting Bnip3 mitochondrial localization by dominant-negative Bnip3 significantly attenuated cell death induced by TAS2R agonist. Collectively the TAS2R agonists chloroquine and quinine modulate mitochondrial structure and function, resulting in ASM cell death. Furthermore, Bnip3 plays a central role in TAS2R agonist-induced ASM functional changes via a mitochondrial pathway. These findings further establish the cellular mechanisms of antimitogenic effects of TAS2R agonists and identify a novel class of receptors and pathways that can be targeted to mitigate airway remodeling as well as bronchoconstriction in obstructive airway diseases

    Wilson chains are not thermal reservoirs

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    Wilson chains, based on a logarithmic discretization of a continuous spectrum, are widely used to model an electronic (or bosonic) bath for Kondo spins and other quantum impurities within the numerical renormalization group method and other numerical approaches. In this short note we point out that Wilson chains can not serve as thermal reservoirs as their temperature changes by a number of order Delta E when a finite amount of energy Delta E is added. This proves that for a large class of non-equilibrium problems they cannot be used to predict the long-time behavior.Comment: 2 page

    Epistasis not needed to explain low dN/dS

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    An important question in molecular evolution is whether an amino acid that occurs at a given position makes an independent contribution to fitness, or whether its effect depends on the state of other loci in the organism's genome, a phenomenon known as epistasis. In a recent letter to Nature, Breen et al. (2012) argued that epistasis must be "pervasive throughout protein evolution" because the observed ratio between the per-site rates of non-synonymous and synonymous substitutions (dN/dS) is much lower than would be expected in the absence of epistasis. However, when calculating the expected dN/dS ratio in the absence of epistasis, Breen et al. assumed that all amino acids observed in a protein alignment at any particular position have equal fitness. Here, we relax this unrealistic assumption and show that any dN/dS value can in principle be achieved at a site, without epistasis. Furthermore, for all nuclear and chloroplast genes in the Breen et al. dataset, we show that the observed dN/dS values and the observed patterns of amino acid diversity at each site are jointly consistent with a non-epistatic model of protein evolution.Comment: This manuscript is in response to "Epistasis as the primary factor in molecular evolution" by Breen et al. Nature 490, 535-538 (2012

    Dendritic ion channel trafficking and plasticity.

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    Dendritic ion channels are essential for the regulation of intrinsic excitability as well as modulating the shape and integration of synaptic signals. Changes in dendritic channel function have been associated with many forms of synaptic plasticity. Recent evidence suggests that dendritic ion channel modulation and trafficking could contribute to plasticity-induced alterations in neuronal function. In this review we discuss our current knowledge of dendritic ion channel modulation and trafficking and their relationship to cellular and synaptic plasticity. We also consider the implications for neuronal function. We argue that to gain an insight into neuronal information processing it is essential to understand the regulation of dendritic ion channel expression and properties

    Recurrence of particles in static and time varying oval billiards

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    Dynamical properties are studied for escaping particles, injected through a hole in an oval billiard. The dynamics is considered for both static and periodically moving boundaries. For the static boundary, two different decays for the recurrence time distribution were observed after exponential decay for short times: A changeover to: (i) power law or; (ii) stretched exponential. Both slower decays are due to sticky orbits trapped near KAM islands, with the stretched exponential apparently associated with a single group of large islands. For time dependent case, survival probability leads to the conclusion that sticky orbits are less evident compared with the static case.Comment: 7 pages, 6 figures, to appear in Phys Lett

    Geometrically-controlled twist transitions in nematic cells

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    We study geometrically-controlled twist transitions of a nematic confined between a sinusoidal grating and a flat substrate. In these cells the transition to the twisted state is driven by surface effects. We have identified the mechanisms responsible for the transition analytically and used exact numerical calculations to study the range of surface parameters where the twist instability occurs. Close to these values the cell operates under minimal external fields or temperature variations
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