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https://www.readbyqxmd.com/read/28092595/command-filter-based-adaptive-neural-tracking-controller-design-for-uncertain-switched-nonlinear-output-constrained-systems
#1
Ben Niu, Yanjun Liu, Guangdeng Zong, Zhaoyu Han, Jun Fu
In this paper, a new adaptive approximation-based tracking controller design approach is developed for a class of uncertain nonlinear switched lower-triangular systems with an output constraint using neural networks (NNs). By introducing a novel barrier Lyapunov function (BLF), the constrained switched system is first transformed into a new system without any constraint, which means the control objectives of the both systems are equivalent. Then command filter technique is applied to solve the so-called "explosion of complexity" problem in traditional backstepping procedure, and radial basis function NNs are directly employed to model the unknown nonlinear functions...
January 16, 2017: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28092579/cooperative-adaptive-output-regulation-for-second-order-nonlinear-multiagent-systems-with-jointly-connected-switching-networks
#2
Wei Liu, Jie Huang
This paper studies the cooperative global robust output regulation problem for a class of heterogeneous second-order nonlinear uncertain multiagent systems with jointly connected switching networks. The main contributions consist of the following three aspects. First, we generalize the result of the adaptive distributed observer from undirected jointly connected switching networks to directed jointly connected switching networks. Second, by performing a new coordinate and input transformation, we convert our problem into the cooperative global robust stabilization problem of a more complex augmented system via the distributed internal model principle...
January 11, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28092498/adaptive-fuzzy-output-feedback-control-for-switched-nonlinear-systems-with-unmodeled-dynamics
#3
Shaocheng Tong, Yongming Li
This paper investigates a robust adaptive fuzzy control stabilization problem for a class of uncertain nonlinear systems with arbitrary switching signals that use an observer-based output feedback scheme. The considered switched nonlinear systems possess the unstructured uncertainties, unmodeled dynamics, and without requiring the states being available for measurement. A state observer which is independent of switching signals is designed to solve the problem of unmeasured states. Fuzzy logic systems are used to identify unknown lumped nonlinear functions so that the problem of unstructured uncertainties can be solved...
February 2017: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28091617/switch-from-sexual-to-parthenogenetic-reproduction-in-a-zebra-shark
#4
Christine L Dudgeon, Laura Coulton, Ren Bone, Jennifer R Ovenden, Severine Thomas
Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28087445/distinct-subcomponents-of-mouse-retinal-ganglion-cell-receptive-fields-are-differentially-altered-by-light-adaptation
#5
C S Cowan, J Sabharwal, R L Seilheimer, S M Wu
The remarkable dynamic range of vision is facilitated by adaptation of retinal sensitivity to ambient lighting conditions. An important mechanism of sensitivity adaptation is control of the spatial and temporal window over which light is integrated. The retina accomplishes this by switching between parallel synaptic pathways with differing kinetics and degrees of synaptic convergence. However, the relative shifts in spatial and temporal integration are not well understood - particularly in the context of the antagonistic spatial surround...
January 10, 2017: Vision Research
https://www.readbyqxmd.com/read/28077643/efficient-vpu-mediated-tetherin-antagonism-by-an-hiv-1-group-o-strain
#6
Katharina Mack, Kathrin Starz, Daniel Sauter, Simon Langer, Frederic Bibollet-Ruche, Gerald H Learn, Christina M Stürzel, Marie Leoz, Jean-Christophe Plantier, Matthias Geyer, Beatrice H Hahn, Frank Kirchhoff
: Simian immunodeficiency viruses (SIVs) use their Nef proteins to counteract the restriction factor tetherin. However, a deletion in human tetherin prevents antagonism by the Nef proteins of SIVcpz and SIVgor, which represent the ape precursors of human immunodeficiency virus type 1 (HIV-1). To promote virus release from infected cells, pandemic HIV-1 group M strains evolved Vpu as tetherin antagonist, while the Nef protein of less widespread HIV-1 group O strains acquired the ability to target a region adjacent to this deletion...
January 11, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28077418/a-novel-humanized-mouse-model-with-significant-improvement-of-class-switched-antigen-specific-antibody-production
#7
Hua Yu, Chiara Borsotti, Jean-Nicolas Schickel, Shu Zhu, Till Strowig, Elizabeth E Eynon, Davor Frleta, Cagan Gurer, Andrew J Murphy, George D Yancopoulos, Eric Meffre, Markus G Manz, Richard A Flavell
Humanized mice are a powerful tool for the study of human hematopoiesis and immune function in vivo. However, the existing models cannot support robust adaptive immune responses, especially the generation of class-switched, antigen-specific antibody responses. Here we describe a new mouse strain, in which human IL6 gene encoding the cytokine that is important for B and T cell differentiation was knocked into its respective mouse locus. The provision of human IL6 not only enhanced thymopoiesis and periphery T-cell engraftment, but also significantly increased class switched memory B cells and serum IgG...
January 11, 2017: Blood
https://www.readbyqxmd.com/read/28075009/the-physiological-costs-of-prey-switching-reinforce-foraging-specialization
#8
Oliver E Hooker, Travis E Van Leeuwen, Colin E Adams
Sympatric speciation is thought to be strongly linked to resource specialization with alternative resource use acting as a fundamental agent driving divergence. However, sympatric speciation through niche expansion is dependent on foraging specialization being consistent over space and time. Standard metabolic rate is the minimal maintenance metabolic rate of an ectotherm in a post-absorptive and inactive state and can constitute a significant portion of an animal's energy budget; thus standard metabolic rate and growth rate are two measures frequently used as an indication of the physiological performance of individuals...
January 11, 2017: Journal of Animal Ecology
https://www.readbyqxmd.com/read/28074027/a-unique-cis-encoded-small-noncoding-rna-is-regulating-legionella-pneumophila-hfq-expression-in-a-life-cycle-dependent-manner
#9
Giulia Oliva, Tobias Sahr, Monica Rolando, Maike Knoth, Carmen Buchrieser
: Legionella pneumophila is an environmental bacterium that parasitizes protozoa, but it may also infect humans, thereby causing a severe pneumonia called Legionnaires' disease. To cycle between the environment and a eukaryotic host, L. pneumophila is regulating the expression of virulence factors in a life cycle-dependent manner: replicating bacteria do not express virulence factors, whereas transmissive bacteria are highly motile and infective. Here we show that Hfq is an important regulator in this network...
January 10, 2017: MBio
https://www.readbyqxmd.com/read/28064149/emerging-roles-for-rna-binding-proteins-as-effectors-and-regulators-of-cardiovascular-disease
#10
REVIEW
Ruben G de Bruin, Ton J Rabelink, Anton Jan van Zonneveld, Eric P van der Veer
The cardiovascular system comprises multiple cell types that possess the capacity to modulate their phenotype in response to acute or chronic injury. Transcriptional and post-transcriptional mechanisms play a key role in the regulation of remodelling and regenerative responses to damaged cardiovascular tissues. Simultaneously, insufficient regulation of cellular phenotype is tightly coupled with the persistence and exacerbation of cardiovascular disease. Recently, RNA-binding proteins such as Quaking, HuR, Muscleblind, and SRSF1 have emerged as pivotal regulators of these functional adaptations in the cardiovascular system by guiding a wide-ranging number of post-transcriptional events that dramatically impact RNA fate, including alternative splicing, stability, localization and translation...
January 6, 2017: European Heart Journal
https://www.readbyqxmd.com/read/28056744/nucleotide-second-messenger-signaling-as-a-target-for-the-control-of-bacterial-biofilm-formation
#11
Alberto J Martín-Rodríguez, Ute Römling
Bacterial biofilm formation and associated phenotypes are the major cause of chronic infection in humans. The major regulator of biofilm formation in Gram-negative and Gram-positive bacteria are nucleotide-based second messenger signaling pathways. Nucleotide-based signaling is a ubiquitous signal transduction mechanism in all domains of life that relay changes in the extracellular or intracellular milieu to protein or RNA effectors, leading to adaptive physiological responses. To date, six bona fide nucleotide signaling pathways, (p)ppGpp, cAMP, cGMP, c-di-AMP, c-di-GMP and cGAMP, have been characterized with respect to basic pathway modules and phenotypic and physiological output...
January 5, 2017: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/28055919/optimal-switching-of-dc-dc-power-converters-using-approximate-dynamic-programming
#12
Ali Heydari
Optimal switching between different topologies in step-down dc-dc voltage converters, with nonideal inductors and capacitors, is investigated in this paper. Challenges including constraint on the inductor current and voltage leakages across the capacitor (due to switching) are incorporated. The objective is generating the desired voltage with low ripples and high robustness toward line and load disturbances. A previously developed tool, which is based on approximate dynamic programming, is adapted for this application...
December 29, 2016: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28051872/hydrophobic-monomer-type-and-hydrophilic-monomer-ionization-modulate-lyotropic-phase-stability-of-diblock-co-oligomer-amphiphiles
#13
Minh Thu Lam, Paul A FitzGerald, Gregory G Warr
The phase behavior and self-assembly structures of a series of amphiphilic diblock co-oligomers comprising an ionisable hydrophilic block (5 to 10 units of acrylic acid) and a hydrophobic block (5 to 20 units of n-butyl acrylate, t-butyl acrylate or ethyl acrylate), synthesized by RAFT polymerization, has been examined by polarizing optical microscopy and small angle x-ray scattering (SAXS). Self-assembled structure and lyotropic phase stability in these systems is highly-responsive to the degree of ionization of the acrylic acid hydrophilic block (i...
January 4, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28051112/pigmentation-plasticity-enhances-crypsis-in-larval-newts-associated-metabolic-cost-and-background-choice-behaviour
#14
Nuria Polo-Cavia, Ivan Gomez-Mestre
In heterogeneous environments, the capacity for colour change can be a valuable adaptation enhancing crypsis against predators. Alternatively, organisms might achieve concealment by evolving preferences for backgrounds that match their visual traits, thus avoiding the costs of plasticity. Here we examined the degree of plasticity in pigmentation of newt larvae (Lissotriton boscai) in relation to predation risk. Furthermore, we tested for associated metabolic costs and pigmentation-dependent background choice behaviour...
January 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28049720/icap-1-monoubiquitination-coordinates-matrix-density-and-rigidity-sensing-for-cell-migration-through-rock2-mrck%C3%AE-balance
#15
Anne-Pascale Bouin, Alexander Kyurmurkov, Myriam Régent-Kloeckner, Anne-Sophie Ribba, Eva Faurobert, Henri-Noël Fournier, Ingrid Bourrin-Reynard, Sandra Manet-Dupé, Christiane Oddou, Martial Balland, Emmanuelle Planus, Corinne Albiges-Rizo
Cell migration is a complex process requiring density and rigidity sensing of the microenvironment to adapt cell migratory speed through focal adhesion and actin cytoskeleton regulation. ICAP-1, a β1 integrin partner, is essential for ensuring integrin activation cycle and focal adhesion formation. We show that ICAP-1 is monoubiquitinated by Smurf1, preventing ICAP-1 binding to β1 integrin. The non-ubiquitinable form of ICAP-1 modifies β1 integrin focal adhesion organization and interferes with fibronectin density sensing...
January 3, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28045298/rats-show-adaptive-choice-in-a-metacognitive-task-with-high-uncertainty
#16
Shoko Yuki, Kazuo Okanoya
Metacognition refers to the use of one's cognitive processes to coordinate behavior. Many higher cognitive functions such as feeling-of-knowing judgment and theory of mind are thought to be metacognitive processes. Although some primate species also show this ability in the form of behavioral control, a rodent model of metacognition is required for advanced studies of this phenomenon at behavioral, molecular, and neural levels. Here we show that rats could reliably be trained in a metacognitive task. The rats were trained to remember the location of a nose-poke hole and later indicate the location via a behavioral task...
January 2017: Journal of Experimental Psychology. Animal Learning and Cognition
https://www.readbyqxmd.com/read/28039134/characterizing-a-family-of-secretory-proteins-associated-with-different-morphotypes-in-cryptococcus-neoformans
#17
Rachana Gyawali, Srijana Upadhyay, Joshua Way, Xiaorong Lin
: Cryptococcus neoformans, an opportunistic human fungal pathogen, can undergo yeast to hyphal transition in response to environmental cues. This morphological transition is associated with changes in the expression of cell surface proteins. The Cryptococcus cell surface and secreted protein Cfl1 is the first identified adhesin in Basidiomycota. Cfl1 is shown to regulate morphology, biofilm formation, and intercellular communication. Four additional homologs of CFL1 are encoded in the Cryptococcus genome: DHA1, DHA2, CPL1, and CFL105 The common features of this gene family are the conserved C-terminal SIGC domain and the presence of an N-terminal signal peptide...
December 30, 2016: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28028477/emergent-adaptive-behaviour-of-grn-controlled-simulated-robots-in-a-changing-environment
#18
Yao Yao, Veronique Storme, Kathleen Marchal, Yves Van de Peer
We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN) that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems...
2016: PeerJ
https://www.readbyqxmd.com/read/28027343/recommendations-for-the-treatment-of-patients-with-parkinson-disease-during-ramadan
#19
Philippe Damier, Jasem Al-Hashel
Importance: Every year, Ramadan fasting is practiced by many Muslim individuals. In cases of chronic disease, religious texts allow fasting to be broken. However, many believers still want to fast even at the risk of damaging their health. To our knowledge, there are no published recommendations on the medical management of Parkinson disease (PD) during Ramadan. Effective treatments exist in PD and usually require several daily drug intakes. Apart from worsening symptoms, interrupting PD treatment might lead to a severe withdrawal syndrome...
December 27, 2016: JAMA Neurology
https://www.readbyqxmd.com/read/28024385/controlling-stiction-in-nano-electro-mechanical-systems-using-liquid-crystals
#20
Oleksandr Buchnev, Nina Podoliak, Thomas Frank, Malgosia Kaczmarek, Liudi Jiang, Vassili A Fedotov
Stiction is one of the major reliability issues limiting practical application of nano-electro-mechanical systems (NEMS), an emerging device technology that exploits mechanical movements on the scale of an integrated electronic circuit. We report on a discovery that stiction can be eliminated by infiltrating NEMS with nematic liquid crystals. We demonstrate this experimentally using a NEMS-based tunable photonic metamaterial, where reliable switching of optical response was achieved for the entire range of nanoscopic structural displacements admitted by the metamaterial design...
December 27, 2016: ACS Nano
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