Search results for "Stability"

showing 10 items of 3085 documents

Telomere shortening and chromosomal instability abrogates proliferation of adult but not embryonic neural stem cells.

2004

Chromosome integrity is essential for cell viability and, therefore, highly proliferative cell types require active telomere elongation mechanisms to grow indefinitely. Consistently, deletion of telomerase activity in a genetically modified mouse strain results in growth impairments in all highly proliferative cell populations analyzed so far. We show that telomere attrition dramatically impairs the in vitro proliferation of adult neural stem cells (NSCs) isolated from the subventricular zone (SVZ) of telomerase-deficient adult mice. Reduced proliferation of postnatal neurogenic progenitors was also observed in vivo, in the absence of exogenous mitogenic stimulation. Strikingly, severe telo…

TelomeraseBiologyMiceGanglia SensoryChromosomal InstabilityAnimalsProgenitor cellMolecular BiologyTelomeraseCell NucleusMice KnockoutStem CellsNeurogenesisBrainTelomereEmbryonic stem cellMolecular biologyNeural stem cellTelomereCell biologyFemaleStem cellTumor Suppressor Protein p53Cell DivisionDevelopmental BiologyAdult stem cellDevelopment (Cambridge, England)
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snoRNPs Regulate Telomerase Activity in Neuroblastoma and Are Associated with Poor Prognosis

2013

AbstractAmplification of the MYCN oncogene is strongly associated with poor prognosis in neuroblastoma (NB). In addition to MYCN amplification, many studies have focused on identifying patients with a poor prognosis based on gene expression profiling. The majority of prognostic signatures today are comprised of large gene lists limiting their clinical application. In addition, although of prognostic significance,most of these signatures fail to identify cellular processes that can explain their relation to prognosis. Here, we determined prognostically predictive genes in a data set containing 251 NBs. Gene Ontology analysis was performed on significant genes with a positive hazard ratio to …

TelomeraseGene knockdownCancer ResearchBiologyBioinformaticsTelomereGene expression profilingOncologyChromosome instabilityCancer researchSmall nucleolar RNAGeneRibonucleoproteinResearch Article
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Preparation and characterization of new low melting ammonium-based ionic liquids with ether functionality

2009

Abstract Eighteen new and three previously known but insufficiently characterized RR´3N+A− and R2R´2N+A− type (R = 2-ethoxyethyl or 4-methoxybenzyl, R´ = methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl, A = Br, BF4 or PF6) quaternary ammonium (QA) salts were synthesized and characterized by using 1H and 13C NMR techniques, mass spectroscopy and elemental analysis. The bromide salts were synthesized either by treating dimethyl formamide with an ether functionalized alkyl bromide in the presence of potassium carbonate or by treating a tertiary amine with an ether functionalized alkyl bromide. The QA tetrafluoroborates and hexafluorophosphates were synthesized by metathesis reaction betw…

TetrafluoroborateTertiary amineOrganic ChemistryInorganic chemistryEtherAnalytical ChemistryInorganic ChemistryPotassium carbonatechemistry.chemical_compoundCrystallinitychemistryBromideIonic liquidPolymer chemistryThermal stabilitySpectroscopyJournal of Molecular Structure
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Zinc oxide application in the textile industry: surface tailoring and water barrier attributes as parameters with direct implication in comfort perfo…

2013

The present study focuses on surface tailoring and water barrier attributes of zinc oxide (ZnO)-polyester composite textile materials. The surface properties, such as surface topography and roughness, composite compositions as well as thermal stability of ZnO-100% polyester textile composite materials treated through a padding process with different concentrations of ZnO dispersions as active agent in water and methanol were studied. The results show that 3% ZnO-textile composite material have enhanced water barrier properties compared with the other compositions; a fact which promises improved properties in terms of comfort. ZnO modification of polyester surfaces leads to a dramatic decre…

TextileMaterials sciencePolymers and Plasticsbusiness.industryComposite numberchemistry.chemical_elementSurface finishZincPaddingPolyesterchemistryChemical Engineering (miscellaneous)Thermal stabilityWettingComposite materialbusinessTextile Research Journal
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Protective effect of paraoxonase-2 against endoplasmic reticulum stress-induced apoptosis is lost upon disturbance of calcium homoeostasis

2008

PON2 (paraoxonase-2) is a ubiquitously expressed antioxidative protein which is largely found in the ER (endoplasmic reticulum). Addressing the cytoprotective functions of PON2, we observed that PON2 overexpression provided significant resistance to ER-stress-induced caspase 3 activation when the ER stress was induced by interference with protein modification (by tunicamycin or dithiothreitol), but not when ER stress was induced by disturbance of Ca2+ homoeostasis (by thapsigargin or A23187). When analysing the underlying molecular events, we found an activation of the PON2 promoter in response to all tested ER-stress-inducing stimuli. However, only tunicamycin and dithiothreitol resulted i…

ThapsigarginRNA StabilityApoptosisCaspase 3Protein degradationEndoplasmic ReticulumBiochemistryGene Expression Regulation EnzymologicCell Linechemistry.chemical_compoundStress PhysiologicalHomeostasisHumansEnzyme InhibitorsPromoter Regions Genetic3' Untranslated RegionsMolecular BiologyCalcimycinIonophoresbiologyAryldialkylphosphataseCalpainTunicamycinEndoplasmic reticulumCalpainCell BiologyTunicamycinCell biologyDithiothreitolchemistryApoptosisbiology.proteinUnfolded protein responseThapsigarginCalcium5' Untranslated RegionsBiochemical Journal
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Non-Linear Hysteretic Instability in Rotating Machinery

2013

The destabilizing influence of the shaft hysteresis on the supercritical whirl of rotating machines can be efficiently counterbalanced by proper external dissipative sources in the supports and/or anisotropic suspension systems. The hysteretic effect may be treated either by dry or viscous models obtaining different but somehow similar results in the hypothesis of small dissipation levels. Thus the linear viscous assumption is often accepted as a crude approximation for a straightforward analysis of the whirling instability. Nevertheless the internal friction should be regarded most likely as non-linear and could be approximated for example by Coulombian models taking thus into account also the releasing effect of some shrink-fit coupling present in the mechanical assembly.
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Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

The increasing interest in Graphene oxide (GO) is due to many issues: the presence of both sp2-conjugated atoms and oxygen-containing functional groups provides a strong hydrophilicity and the possibility to further functionalize it with other molecules (i.e. π-π interactions covalent attachment etc.) [1]. Furthermore since the GO is biocompatible and noncytotoxic many studies have been recently focused on the development of GO-based nanodevices for bioimaging DNA detection drug delivery. Due to their low cytotoxicity and large internal surface area silica nanoparticles have been taken into account as promising material for biolabeling and drug loading/delivery. Particular consideration has recently been demonstrated for GO-silica composites because of the potentialities for electrical applications their chemical inertia and stability toward ions exposure. The possibility to combine the extraordinary properties of GO and silica offers several advantages for the realization of nanoprobes for biological applications and of biosensor [12]. The strategy for the fabrication of GO-nanosilica nanohybrids can be schematized as follows: (i) synthesis of GO by oxidizing graphite powder with the method described by Marcano et al. [3] (ii) Preparation of oxygen-loaded silica nanoparticles by thermal treatments in controlled atmosphere in order to induce high NIR emission at 1272 nm from high purity silica nanoparticles. (iii) preparation of GrO-silica nanohybrid films via rapid solvent casting in water. The nanohybrids were tested by XPS FTIR Raman analysis UV photoluminescence analysis TGA Zeta potential measurements electrical tests AFM and SEM. Several nanohybrids were prepared by combining two different typologies of GO and two different samples of silica.
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Diffusive neural network

2002

Abstract A non-connectionist model of a neuronal network based on passive diffusion of neurotransmitters is presented as an alternative to hard-wired artificial neural networks. Classic thermodynamical approach shows that the diffusive network is capable of exhibiting asymptotic stability and a dynamics resembling that of a chaotic system. Basic computational capabilities of the net are discussed based on the equivalence with a Turing machine. The model offers a way to represent mass-sustained brain functions in terms of recurrent behaviors in the phase space.

Theoretical computer scienceQuantitative Biology::Neurons and CognitionArtificial neural networkComputer scienceCognitive NeuroscienceChaoticTopologyComputer Science ApplicationsTuring machinesymbols.namesakeRecurrent neural networkExponential stabilityArtificial IntelligencePhase spacesymbolsBiological neural networkStochastic neural networkNeurocomputing
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Consensus in Noncooperative Dynamic Games: a Multi-Retailer Inventory Application

2008

We focus on Nash equilibria and Pareto optimal Nash equilibria for a finite horizon noncooperative dynamic game with a special structure of the stage cost. We study the existence of these solutions by proving that the game is a potential game. For the single-stage version of the game, we characterize the aforementioned solutions and derive a consensus protocol that makes the players converge to the unique Pareto optimal Nash equilibrium. Such an equilibrium guarantees the interests of the players and is also social optimal in the set of Nash equilibria. For the multistage version of the game, we present an algorithm that converges to Nash equilibria, unfortunately, not necessarily Pareto op…

TheoryofComputation_MISCELLANEOUSComputer Science::Computer Science and Game TheoryCorrelated equilibriumSequential gameComputer scienceDynamic programmingSubgame perfect equilibriumsymbols.namesakeCoordination gameElectrical and Electronic EngineeringRisk dominanceFolk theoremPrice of stabilityNon-credible threatGame theoryCentipede gameImplementation theoryNon-cooperative gameInventoryNormal-form gameStochastic gameComputingMilieux_PERSONALCOMPUTINGTheoryofComputation_GENERALComputer Science ApplicationsConsensus protocols; Dynamic programming; Game theory; InventoryConsensus protocolsZero-sum gameControl and Systems EngineeringNash equilibriumEquilibrium selectionBest responsesymbolsRepeated gameEpsilon-equilibriumConsensus protocols; Dynamic programming; Game theory; Inventory;Potential gameSolution conceptMathematical economicsGame theory
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Existence and Optimality of Nash Equilibria in Inventory Games

2005

Abstract This paper studies the stability and optimality of a distributed consensus protocol for n -player repeated non cooperative games under incomplete information. At each stage, the players choose binary strategies and incur in a payoff monotonically decreasing with the number of active players. The game is specialized to an inventory application, where fixed costs are shared among all retailers, interested in whether reordering or not from a common warehouse. The authors focus on Pareto optimality as a measure of coordination of reordering strategies, proving that there exists a unique Pareto optimal Nash equilibrium that verifies certain stability conditions.

TheoryofComputation_MISCELLANEOUSComputer Science::Computer Science and Game TheoryNon-cooperative gameMathematical optimizationStochastic gameTheoryofComputation_GENERALInventory control Stability Optimality Nash equilibriumInventory control; Nash equilibrium; Optimality; Stability;symbols.namesakeNash equilibriumBest responseRepeated gamesymbolsEconomicsCoordination gameEpsilon-equilibriumRisk dominanceMathematical economics
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