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HIgh Frequency Oscillation

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https://www.readbyqxmd.com/read/28546634/high-gain-graphene-transistors-with-a-thin-alox-top-gate-oxide
#1
Erica Guerriero, Paolo Pedrinazzi, Aida Mansouri, Omid Habibpour, Michael Winters, Niklas Rorsman, Ashkan Behnam, Enrique A Carrion, Amaia Pesquera, Alba Centeno, Amaia Zurutuza, Eric Pop, Herbert Zirath, Roman Sordan
The high-frequency performance of transistors is usually assessed by speed and gain figures of merit, such as the maximum oscillation frequency f max, cutoff frequency f T, ratio f max/f T, forward transmission coefficient S 21, and open-circuit voltage gain A v. All these figures of merit must be as large as possible for transistors to be useful in practical electronics applications. Here we demonstrate high-performance graphene field-effect transistors (GFETs) with a thin AlOx gate dielectric which outperform previous state-of-the-art GFETs: we obtained f max/f T > 3, A v > 30 dB, and S 21 = 12...
May 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28546342/intrinsic-frequency-response-patterns-in-mechano-sensory-neurons-of-the-leech
#2
Linda Fischer, Frank Scherbarth, Boris Chagnaud, Felix Felmy
Animals employ mechano-sensory systems to detect and explore their environment. Mechano-sensation encompasses stimuli like constant pressure, surface movement or vibrations at various intensities that need to be segregated in the central nervous system. Besides different receptor structures sensory filtering via intrinsic response properties could provide a convenient way to solve this problem. In leech, three major mechano-sensory cell types can be distinguished according to their stimulus sensitivity into nociceptive, pressure and touch cells...
May 25, 2017: Biology Open
https://www.readbyqxmd.com/read/28546209/quantum-sensing-with-arbitrary-frequency-resolution
#3
J M Boss, K S Cujia, J Zopes, C L Degen
Quantum sensing takes advantage of well-controlled quantum systems for performing measurements with high sensitivity and precision. We have implemented a concept for quantum sensing with arbitrary frequency resolution, independent of the qubit probe and limited only by the stability of an external synchronization clock. Our concept makes use of quantum lock-in detection to continuously probe a signal of interest. Using the electronic spin of a single nitrogen-vacancy center in diamond, we demonstrate detection of oscillating magnetic fields with a frequency resolution of 70 microhertz over a megahertz bandwidth...
May 26, 2017: Science
https://www.readbyqxmd.com/read/28543030/defining-epileptogenic-networks-contribution-of-seeg-and-signal-analysis
#4
REVIEW
Fabrice Bartolomei, Stanislas Lagarde, Fabrice Wendling, Aileen McGonigal, Viktor Jirsa, Maxime Guye, Christian Bénar
Epileptogenic networks are defined by the brain regions involved in the production and propagation of epileptic activities. In this review we describe the historical, methodologic, and conceptual bases of this model in the analysis of electrophysiologic intracerebral recordings. In the context of epilepsy surgery, the determination of cerebral regions producing seizures (i.e., the "epileptogenic zone") is a crucial objective. In contrast with a traditional focal vision of focal drug-resistant epilepsies, the concept of epileptogenic networks has been progressively introduced as a model better able to describe the complexity of seizure dynamics and realistically describe the distribution of epileptogenic anomalies in the brain...
May 20, 2017: Epilepsia
https://www.readbyqxmd.com/read/28539912/using-brain-oscillations-and-corticospinal-excitability-to-understand-and-predict-post-stroke-motor-function
#5
Aurore Thibaut, Marcel Simis, Linamara Rizzo Battistella, Chiara Fanciullacci, Federica Bertolucci, Rodrigo Huerta-Gutierrez, Carmelo Chisari, Felipe Fregni
What determines motor recovery in stroke is still unknown and finding markers that could predict and improve stroke recovery is a challenge. In this study, we aimed at understanding the neural mechanisms of motor function recovery after stroke using neurophysiological markers by means of cortical excitability (transcranial magnetic stimulation-TMS) and brain oscillations (electroencephalography-EEG). In this cross-sectional study, 55 subjects with chronic stroke (62 ± 14 yo, 17 women, 32 ± 42 months post-stroke) were recruited in two sites...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28532653/hippocampal-ca1-local-field-potential-oscillations-induced-by-olfactory-cue-of-liked-food
#6
Nifareeda Samerphob, Dania Cheaha, Surapong Chatpun, Ekkasit Kumarnsit
Eating motivation is induced not only by negative energy balance but also food related cues. However, neural processing for acquisition of learned food preference remains to be established. This study aimed to identify hippocampal neural signaling in response to olfactory cue (chocolate scent) after completion of repetitive chocolate sessions. Male Swiss albino mice implanted with intracranial electrode into the hippocampus were used for local field potential (LFP) recording. Animals were given chocolate sessions (a piece of 2 g chocolate per each mouse to eat on day 1, 3, 5 and 7)...
May 19, 2017: Neurobiology of Learning and Memory
https://www.readbyqxmd.com/read/28529384/the-pelskin-project-part-v-towards-the-control-of-the-flow-around-aerofoils-at-high-angle-of-attack-using-a-self-activated-deployable-flap
#7
Marco E Rosti, Laura Kamps, Christoph Bruecker, Mohammad Omidyeganeh, Alfredo Pinelli
During the flight of birds, it is often possible to notice that some of the primaries and covert feathers on the upper side of the wing pop-up under critical flight conditions, such as the landing approach or when stalking their prey (see Fig. 1) . It is often conjectured that the feathers pop up plays an aerodynamic role by limiting the spread of flow separation . A combined experimental and numerical study was conducted to shed some light on the physical mechanism determining the feathers self actuation and their effective role in controlling the flow field in nominally stalled conditions...
2017: Meccanica
https://www.readbyqxmd.com/read/28522369/electroencephalographic-monitoring-during-sevoflurane-anaesthesia-in-an-amyotrophic-lateral-sclerosis-patient-with-locked-in-state
#8
Kazuko Hayashi, Ryuhei Araki, Akiko Tanaka
Recently, the cognitive abilities of patients with amyotrophic lateral sclerosis (ALS) have been found to be impaired along with the neurodegeneration of motor neurons. Electroencephalography (EEG) of end-stage ALS patients has reportedly shown specific features based on neuronal network modulations, differing from EEG of other patients with cognitive failure and dementia. However, EEG of end-stage ALS patients during anaesthesia has not yet been reported. A 64-year-old male ALS patient with locked-in state (LIS), supported by tracheostomy positive-pressure ventilation (TPPV) and enteral nourishment for 9years, underwent scheduled general anaesthesia for repair of a fractured mandible...
May 15, 2017: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/28521267/epileptogenic-high-frequency-oscillations-skip-the-motor-area-in-children-with-multilobar-drug-resistant-epilepsy
#9
Yasushi Iimura, Kevin Jones, Kyoko Hattori, Yushi Okazawa, Atsuko Noda, Kana Hoashi, Yutaka Nonoda, Eishi Asano, Tomoyuki Akiyama, Cristina Go, Ayako Ochi, O Carter Snead, Elizabeth J Donner, James T Rutka, James M Drake, Hiroshi Otsubo
OBJECTIVE: Subtotal hemispherectomy involves the resection of multiple lobes in children with drug-resistant epilepsy, skipping the motor area (MA). We determined epileptogenicity using the occurrence rate (OR) of high-frequency oscillations (HFOs) and the modulation index (MI), demonstrating strength of coupling between HFO and slow wave. We hypothesized that epileptogenicity increased over the multiple lobes but skipped the MA. METHODS: We analyzed 23 children (14 subtotal hemispherectomy; 9 multilobar resections)...
March 24, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28510457/spatiotemporal-evolution-of-coherent-elastic-strain-waves-in-a-single-mos2-flake
#10
Alyssa J McKenna, Jeffrey K Eliason, David J Flannigan
We use bright-field imaging in an ultrafast electron microscope to spatiotemporally map the evolution of photoexcited coherent strain waves in a single, micrometer-size flake of MoS2. Following in situ femtosecond photoexcitation, we observe individual wave trains emerge from discrete nanoscale morphological features and propagate in-plane along specific wave vectors at approximately the speed of sound (7 nm/ps). Over the span of several hundred picoseconds, the 50 GHz wave trains (20 ps periods) are observed to undergo phonon-phonon scattering and wave-train interference, resulting in a transition to larger-scale, incoherent structural dynamics...
May 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28505605/thickness-and-optical-constants-calculation-for-chalcogenide-alkali-metal-se80te8-nacl-12-thin-film
#11
M I Abd-Elrahman, A A Abu-Sehly, Y M Bakier, M M Hafiz
Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra...
May 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28505495/generalized-boussinesq-scriven-surface-fluid-model-with-curvature-dissipation-for-liquid-surfaces-and-membranes
#12
Oscar F Aguilar Gutierrez, Edtson E Herrera Valencia, Alejandro D Rey
Curvature dissipation is relevant in synthetic and biological processes, from fluctuations in semi-flexible polymer solutions, to buckling of liquid columns, tomembrane cell wall functioning. We present a micromechanical model of curvature dissipation relevant to fluid membranes and liquid surfaces based on a parallel surface parameterization and a stress constitutive equation appropriate for anisotropic fluids and fluid membranes.The derived model, aimed at high curvature and high rate of change of curvature in liquid surfaces and membranes, introduces additional viscous modes not included in the widely used 2D Boussinesq-Scriven rheological constitutive equation for surface fluids...
May 8, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28494995/high-accuracy-detection-of-airway-obstruction-in-asthma-using-machine-learning-algorithms-and-forced-oscillation-measurements
#13
Jorge L M Amaral, Agnaldo J Lopes, Juliana Veiga, Alvaro C D Faria, Pedro L Melo
BACKGROUND AND OBJECTIVES: The main pathologic feature of asthma is episodic airway obstruction. This is usually detected by spirometry and body plethysmography. These tests, however, require a high degree of collaboration and maximal effort on the part of the patient. There is agreement in the literature that there is a demand of research into new technologies to improve non-invasive testing of lung function. The purpose of this study was to develop automatic classifiers to simplify the clinical use and to increase the accuracy of the forced oscillation technique (FOT) in the diagnosis of airway obstruction in patients with asthma...
June 2017: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/28487527/development-of-frequency-based-taste-receptors-using-bioinspired-glucose-nanobiosensor
#14
Amin TermehYousefi, Katsumi Tateno, Samira Bagheri, Hirofumi Tanaka
A method to fabricate a bioinspired nanobiosensor using electronic-based artificial taste receptors for glucose diagnosis is presented. Fabricated bioinspired glucose nanobiosensor designated based on an artificial taste bud including an amperometric glucose biosensor and taste bud-inspired circuits. In fact, the design of the taste bud-inspired circuits was inspired by the signal-processing mechanism of taste nerves which involves two layers. The first, known as a type II cell, detects the glucose by glucose oxidase and transduces the current signal obtained for the pulse pattern is conducted to the second layer, called type III cell, to induce synchronisation of the neural spiking activity...
May 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28482580/luteinizing-hormone-releasing-hormone-targeted-superparamagnetic-gold-nanoshells-for-a-combination-therapy-of-hyperthermia-and-controlled-drug-delivery
#15
Faruq Mohammad, Hamad A Al-Lohedan
In this, we developed superparamagnetic iron oxide nanoparticles (SPIONs) to be appropriate for the diagnosis and treatment of cancer cells by means of magnetic resonance imaging (MRI) and magnetically controlled hyperthermia/drug delivery (respectively). For the preparation of composite, we started with SPIONs, followed by its coating with gold to form SPIONs@Au, which further conjugated with luteinizing hormone-releasing hormone (LHRH) protein by making use of the cysteamine (Cyst) space linker and finally loaded with 5-Fluororacil (5-Fu) anticancer drug to form SPIONs@Au-Cyst-LHRH_5-Fu composite...
July 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28472661/chronic-loss-of-ca2-transmission-leads-to-hippocampal-hyperexcitability
#16
Roman Boehringer, Denis Polygalov, Arthur J Y Huang, Steven J Middleton, Vincent Robert, Marie E Wintzer, Rebecca A Piskorowski, Vivien Chevaleyre, Thomas J McHugh
Hippocampal CA2 pyramidal cells project into both the neighboring CA1 and CA3 subfields, leaving them well positioned to influence network physiology and information processing for memory and space. While recent work has suggested unique roles for CA2, including encoding position during immobility and generating ripple oscillations, an interventional examination of the integrative functions of these connections has yet to be reported. Here we demonstrate that CA2 recruits feedforward inhibition in CA3 and that chronic genetically engineered shutdown of CA2-pyramidal-cell synaptic transmission consequently results in increased excitability of the recurrent CA3 network...
May 3, 2017: Neuron
https://www.readbyqxmd.com/read/28471492/oscillating-devices-for-airway-clearance-in-people-with-cystic-fibrosis
#17
REVIEW
Lisa Morrison, Stephanie Innes
BACKGROUND: Chest physiotherapy is widely prescribed to assist the clearance of airway secretions in people with cystic fibrosis. Oscillating devices generate intra- or extra-thoracic oscillations orally or external to the chest wall. Internally they create variable resistances within the airways, generating controlled oscillating positive pressure which mobilises mucus. Extra-thoracic oscillations are generated by forces outside the respiratory system, e.g. high frequency chest wall oscillation...
May 4, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28463818/high-frequency-somatosensory-stimulation-increases-sensori-motor-inhibition-and-leads-to-perceptual-improvement-in-healthy-subjects
#18
Lorenzo Rocchi, Roberto Erro, Elena Antelmi, Alfredo Berardelli, Michele Tinazzi, Rocco Liguori, Kailash Bhatia, John Rothwell
OBJECTIVE: High frequency repetitive somatosensory stimulation (HF-RSS), which is a patterned electric stimulation applied to the skin through surface electrodes, improves two-point discrimination, somatosensory temporal discrimination threshold (STDT) and motor performance in humans. However, the mechanisms which underlie these changes are still unknown. In particular, we hypothesize that refinement of inhibition might be responsible for the improvement in spatial and temporal perception...
June 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28462067/optimizing-qplus-sensor-assemblies-for-simultaneous-scanning-tunneling-and-noncontact-atomic-force-microscopy-operation-based-on-finite-element-method-analysis
#19
Omur E Dagdeviren, Udo D Schwarz
Quartz tuning forks that have a probe tip attached to the end of one of its prongs while the other prong is arrested to a holder ("qPlus" configuration) have gained considerable popularity in recent years for high-resolution atomic force microscopy imaging. The small size of the tuning forks and the complexity of the sensor architecture, however, often impede predictions on how variations in the execution of the individual assembly steps affect the performance of the completed sensor. Extending an earlier study that provided numerical analysis of qPlus-style setups without tips, this work quantifies the influence of tip attachment on the operational characteristics of the sensor...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28458615/gravitational-waves-and-electrodynamics-new-perspectives
#20
Francisco Cabral, Francisco S N Lobo
Given the recent direct measurement of gravitational waves (GWs) by the LIGO-VIRGO collaboration, the coupling between electromagnetic fields and gravity have a special relevance since it opens new perspectives for future GW detectors and also potentially provides information on the physics of highly energetic GW sources. We explore such couplings using the field equations of electrodynamics on (pseudo) Riemann manifolds and apply it to the background of a GW, seen as a linear perturbation of Minkowski geometry...
2017: European Physical Journal. C, Particles and Fields
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