1,894 research outputs found
Telemetry system driven by radiation power for use in gravitational wave detectors
2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Highly Conductive Graphene/Ag Hybrid Fibers for Flexible Fiber-Type Transistors
Mechanically robust, flexible, and electrically conductive textiles are highly suitable for use in wearable electronic applications. In this study, highly conductive and flexible graphene/Ag hybrid fibers were prepared and used as electrodes for planar and fiber-type transistors. The graphene/Ag hybrid fibers were fabricated by the wet-spinning/drawing of giant graphene oxide and subsequent functionalization with Ag nanoparticles. The graphene/Ag hybrid fibers exhibited record-high electrical conductivity of up to 15,800 S cm(-1). As the graphene/Ag hybrid fibers can be easily cut and placed onto flexible substrates by simply gluing or stitching, ion gel-gated planar transistors were fabricated by using the hybrid fibers as source, drain, and gate electrodes. Finally, fibertype transistors were constructed by embedding the graphene/Ag hybrid fiber electrodes onto conventional polyurethane monofilaments, which exhibited excellent flexibility (highly bendable and rollable properties), high electrical performance (mu(h) = 15.6 cm(2) V-1 s(-1), I-on/I-off > 10(4)), and outstanding device performance stability (stable after 1,000 cycles of bending tests and being exposed for 30 days to ambient conditions). We believe that our simple methods for the fabrication of graphene/Ag hybrid fiber electrodes for use in fiber-type transistors can potentially be applied to the development all-organic wearable devices.111912Ysciescopu
An HMM-Based Framework for Supporting Accurate Classification of Music Datasets
open3In this paper, we use Hidden Markov Models (HMM) and Mel-Frequency Cepstral Coecients (MFCC) to build statistical models of classical music composers directly from the music datasets. Several
musical pieces are divided by instruments (String, Piano, Chorus, Orchestra), and, for each instrument, statistical models of the composers are computed.We selected 19 dierent composers spanning four centuries by using a total number of 400 musical pieces. Each musical piece is classied as belonging to a composer if the corresponding HMM gives the highest likelihood for that piece. We show that the so-developed models can be used to obtain useful information on the correlation between the composers. Moreover, by using the maximum likelihood approach, we also classied the instrumentation used by the same composer. Besides as an analysis tool, the described approach has been used as a classier. This overall originates an HMM-based framework for supporting accurate classication of music datasets. On a dataset of String Quartet movements, we obtained an average composer classication accuracy of more than 96%. As regards instrumentation classication, we obtained an average classication of slightly less than 100% for Piano, Orchestra and String Quartet. In this paper, the most signicant results coming from our experimental assessment and analysis are reported and discussed in detail.openCuzzocrea, Alfredo; Mumolo, Enzo; Vercelli, GianniCuzzocrea, Alfredo; Mumolo, Enzo; Vercelli, Giann
Random attractors for degenerate stochastic partial differential equations
We prove the existence of random attractors for a large class of degenerate
stochastic partial differential equations (SPDE) perturbed by joint additive
Wiener noise and real, linear multiplicative Brownian noise, assuming only the
standard assumptions of the variational approach to SPDE with compact
embeddings in the associated Gelfand triple. This allows spatially much rougher
noise than in known results. The approach is based on a construction of
strictly stationary solutions to related strongly monotone SPDE. Applications
include stochastic generalized porous media equations, stochastic generalized
degenerate p-Laplace equations and stochastic reaction diffusion equations. For
perturbed, degenerate p-Laplace equations we prove that the deterministic,
infinite dimensional attractor collapses to a single random point if enough
noise is added.Comment: 34 pages; The final publication is available at
http://link.springer.com/article/10.1007%2Fs10884-013-9294-
A new vicious cycle involving glutamate excitotoxicity, oxidative stress and mitochondrial dynamics
Glutamate excitotoxicity leads to fragmented mitochondria in neurodegenerative diseases, mediated by nitric oxide and S-nitrosylation of dynamin-related protein 1, a mitochondrial outer membrane fission protein. Optic atrophy gene 1 (OPA1) is an inner membrane protein important for mitochondrial fusion. Autosomal dominant optic atrophy (ADOA), caused by mutations in OPA1, is a neurodegenerative disease affecting mainly retinal ganglion cells (RGCs). Here, we showed that OPA1 deficiency in an ADOA model influences N-methyl-D-aspartate (NMDA) receptor expression, which is involved in glutamate excitotoxicity and oxidative stress. Opa1enu/+ mice show a slow progressive loss of RGCs, activation of astroglia and microglia, and pronounced mitochondrial fission in optic nerve heads as found by electron tomography. Expression of NMDA receptors (NR1, 2A, and 2B) in the retina of Opa1enu/+ mice was significantly increased as determined by western blot and immunohistochemistry. Superoxide dismutase 2 (SOD2) expression was significantly decreased, the apoptotic pathway was activated as Bax was increased, and phosphorylated Bad and BcL-xL were decreased. Our results conclusively demonstrate that not only glutamate excitotoxicity and/or oxidative stress alters mitochondrial fission/fusion, but that an imbalance in mitochondrial fission/fusion in turn leads to NMDA receptor upregulation and oxidative stress. Therefore, we propose a new vicious cycle involved in neurodegeneration that includes glutamate excitotoxicity, oxidative stress, and mitochondrial dynamics
Transurethral marking incision of the bladder neck: a helpful technique in robot-assisted laparoscopic radical prostatectomy involving post-transurethral resection of the prostate and cancers protruding into the bladder neck
Thermal Properties of Graphene, Carbon Nanotubes and Nanostructured Carbon Materials
Recent years witnessed a rapid growth of interest of scientific and
engineering communities to thermal properties of materials. Carbon allotropes
and derivatives occupy a unique place in terms of their ability to conduct
heat. The room-temperature thermal conductivity of carbon materials span an
extraordinary large range - of over five orders of magnitude - from the lowest
in amorphous carbons to the highest in graphene and carbon nanotubes. I review
thermal and thermoelectric properties of carbon materials focusing on recent
results for graphene, carbon nanotubes and nanostructured carbon materials with
different degrees of disorder. A special attention is given to the unusual size
dependence of heat conduction in two-dimensional crystals and, specifically, in
graphene. I also describe prospects of applications of graphene and carbon
materials for thermal management of electronics.Comment: Review Paper; 37 manuscript pages; 4 figures and 2 boxe
Evaluation of Microbubbles as Contrast Agents for Ultrasonography and Magnetic Resonance Imaging
Background: Microbubbles (MBs) can serve as an ultrasound contrast agent, and has the potential for magnetic resonance imaging (MRI). Due to the relatively low effect of MBs on MRI, it is necessary to develop new MBs that are more suitable for MRI. In this study, we evaluate the properties of SonoVueH and custom-made Fe 3O 4-nanoparticle-embedded microbubbles (Fe3O4-MBs) in terms of contrast agents for ultrsonography (US) and MRI. Methodology/Principal Findings: A total of 20 HepG2 subcutaneous-tumor-bearing nude mice were randomly assigned to 2 groups (i.e., n = 10 mice each group), one for US test and the other for MRI test. Within each group, two tests were performed for each mouse. The contrast agent for the first test is SonoVueH, and the second is Fe 3O 4-MBs. US was performed using a Technos MPX US system (Esaote, Italy) with a contrast-tuned imaging (CnTI TM) mode. MRI was performed using a 7.0T Micro-MRI (PharmaScan, Bruker Biospin GmbH, Germany) with an EPI-T2 * sequence. The data of signal-to-noise ratio (SNR) from the region-of-interest of each US and MR image was calculated by ImageJ (National Institute of Health, USA). In group 1, enhancement of SonoVueH was significantly higher than Fe 3O 4-MBs on US (P,0.001). In group 2, negative enhancement of Fe3O4-MBs was significantly higher than SonoVueH on MRI (P,0.001). The time to peak showed no significant differences between US and MRI, both of which used the same MBs (P.0.05). The SNR analysis of the enhancement process reveals a strong negative correlation in both cases (i.e., SonoVueH r=20.733, Fe 3O 4-MBs r = 20.903
Postoperative air leak grading is useful to predict prolonged air leak after pulmonary lobectomy
Two step activation of FOXO3 by AMPK generates a coherent feed-forward loop determining excitotoxic cell fate
Cerebral ischemia and excitotoxic injury induce transient or permanent bioenergetic failure, and may result in neuronal apoptosis or necrosis. We have previously shown that ATP depletion and activation of AMP-activated protein kinase (AMPK) during excitotoxic injury induces neuronal apoptosis by transcription of the proapoptotic BH3 only protein, Bim. AMPK, however, also exerts pro-survival functions in neurons. The molecular switches that determine these differential outcomes are not well understood. Using an approach combining biochemistry, single cell imaging and computational modeling, we here demonstrate that excitotoxic injury activated the bim promoter in a FOXO3-dependent manner. The activation of AMPK reduced AKT activation, and led to dephosphorylation and nuclear translocation of FOXO3. Subsequent mutation studies indicated that bim gene activation during excitotoxic injury required direct FOXO3 phosphorylation by AMPK in the nucleus as a second activation step. Inhibition of this phosphorylation prevented Bim expression and protected neurons against excitotoxic and oxygen/glucose deprivation-induced injury. Systems analysis and computational modeling revealed that these two activation steps defined a coherent feedforward loop; a network motif capable of filtering any effects of short-term AMPK activation on bim gene induction. This may prevent unwanted AMPK-mediated Bim expression and apoptosis during transient or physiological bioenergetic stress
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