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High frequency oscillations

Alessandro Micarelli, Andrea Viziano, David Della-Morte, Ivan Augimeri, Marco Alessandrini
OBJECTIVE: Considering the altered multisensory signal compensation during senescence, the aim of the present study was to evaluate the integration rearrangements in unilateral vestibular hypofunction (UVH) during age-related cognitive decline. STUDY DESIGN: Cross-sectional study. SETTING: Longitudinal cohort study unit and of University tertiary referral center. PATIENTS: Older UVH individuals ≥ 55 years with Mild Cognitive Impairment (MCI) or Alzheimer Disease (AD) and matched UVH control group with age-appropriate cognitive function...
March 15, 2018: Otology & Neurotology
Yuchen Shao, Xiuyou Han, Ming Li, Mingshan Zhao
Low-power radio frequency (RF) signal detection is highly desirable for many applications, ranging from wireless communication to radar systems. A tunable optoelectronic oscillator (OEO) based on a phase-shifted fiber Bragg grating for detecting low-power RF signals is proposed and experimentally demonstrated. When the frequency of the input RF signal is matched with the potential oscillation mode of the OEO, it is detected and amplified. The frequency of the RF signal under detection can be estimated simultaneously by scanning the wavelength of the laser source...
March 15, 2018: Optics Letters
Philipp T Dumitrescu, Romain Vasseur, Andrew C Potter
We simulate the dynamics of a disordered interacting spin chain subject to a quasiperiodic time-dependent drive, corresponding to a stroboscopic Fibonacci sequence of two distinct Hamiltonians. Exploiting the recursive drive structure, we can efficiently simulate exponentially long times. After an initial transient, the system exhibits a long-lived glassy regime characterized by a logarithmically slow growth of entanglement and decay of correlations analogous to the dynamics at the many-body delocalization transition...
February 16, 2018: Physical Review Letters
C J Cline Ii, U H Faul, E C David, A J Berry, I Jackson
Lateral variations of seismic wave speeds and attenuation (dissipation of strain energy) in the Earth's upper mantle have the potential to map key characteristics such as temperature, major-element composition, melt fraction and water content. The inversion of these data into meaningful representations of physical properties requires a robust understanding of the micromechanical processes that affect the propagation of seismic waves. Structurally bound water (hydroxyl) is believed to affect seismic properties but this has yet to be experimentally quantified...
March 14, 2018: Nature
Efthymios Maneas, Wenfeng Xia, Olumide Ogunlade, Martina Fonseca, Daniil I Nikitichev, Anna L David, Simeon J West, Sebastien Ourselin, Jeremy C Hebden, Tom Vercauteren, Adrien E Desjardins
Tissue-mimicking phantoms are widely used for the calibration, evaluation and standardisation of medical imaging systems, and for clinical training. For photoacoustic imaging, tissue-mimicking materials (TMMs) that have tuneable optical and acoustic properties, high stability, and mechanical robustness are highly desired. In this study, gel wax is introduced as a TMM that satisfies these criteria for developing photoacoustic imaging phantoms. The reduced scattering and optical absorption coefficients were independently tuned with the addition of TiO2 and oil-based inks...
March 1, 2018: Biomedical Optics Express
Tianxiao Jiang, Su Liu, Giuseppe Pellizzer, Aydin Aydoseli, Sacit Karamursel, Pulat A Sabanci, Altay Sencer, Candan Gurses, Nuri F Ince
Functional mapping of eloquent cortex before the resection of a tumor is a critical procedure for optimizing survival and quality of life. In order to locate the hand area of the motor cortex in two patients with low-grade gliomas (LGG), we recorded electrocorticogram (ECoG) from a 113 channel hybrid high-density grid (64 large contacts with diameter of 2.7 mm and 49 small contacts with diameter of 1 mm) while they executed hand clenching movements. We investigated the spatio-spectral characteristics of the neural oscillatory activity and observed that, in both patients, the hand movements were consistently associated with a wide spread power decrease in the low frequency band (LFB: 8-32 Hz) and a more localized power increase in the high frequency band (HFB: 60-280 Hz) within the sensorimotor region...
2018: Frontiers in Neuroscience
Frederick Hakelberg, Philip Kiefer, Matthias Wittemer, Tobias Schaetz, Ulrich Warring
Well controlled and highly stable magnetic fields are desired for a wide range of applications in physical research, including quantum metrology, sensing, information processing, and simulation. Here we introduce a low-cost hybrid assembly of rare-earth magnets and magnetic field coils to generate a field strength of [Formula: see text]10.9 mT with a calculated spatial variation of less than 10-6 within a diameter of spherical volume of 150 μm. We characterise its tuneability and stability performance using a single Mg+ atom confined in a radio-frequency surface-electrode trap under ultra-high vacuum conditions...
March 13, 2018: Scientific Reports
Enya Daynes, Neil J Greening, Theresa C Harvey-Dunstan, Sally J Singh
BACKGROUND: COPD is characterized by expiratory flow limitation, which results in symptomatic dyspnea and reduced exercise capacity. Changes in breathing mechanics mean the respiratory muscles are unable to respond to the ventilatory demands, increasing the sensation of dyspnea. A high-frequency oscillating device has been developed to improve dyspnea in patients with COPD. We conducted a feasibility trial to gain insight into the potential for recruitment, retention, and study design for a future randomized controlled trial...
March 13, 2018: Respiratory Care
Francisco Pelaez, Navid Manuchehrabadi, Priyatanu Roy, Harishankar Natesan, Yiru Wang, Emilian Racila, Heather Fong, Kevin Zeng, Abby M Silbaugh, John C Bischof, Samira M Azarin
Currently, there are very few therapeutic options for treatment of metastatic disease, as it often remains undetected until the burden of disease is too high. Microporous poly(ε-caprolactone) biomaterials have been shown to attract metastasizing breast cancer cells in vivo early in tumor progression. In order to enhance the therapeutic potential of these scaffolds, they were modified such that infiltrating cells could be eliminated with non-invasive focal hyperthermia. Metal disks were incorporated into poly(ε-caprolactone) scaffolds to generate heat through electromagnetic induction by an oscillating magnetic field within a radiofrequency coil...
February 28, 2018: Biomaterials
Fatemeh Khadjevand, Jan Cimbalnik, Gregory A Worrell
High-frequency oscillations (HFOs: 100 - 600 Hz) have been widely proposed as biomarkers of epileptic brain tissue. In addition, HFOs over a broader range of frequencies spanning 30 - 2000 Hz are potential biomarkers of both physiological and pathological brain processes. The majority of the results from humans with focal epilepsy have focused on HFOs recorded directly from the brain with intracranial EEG (iEEG) in the high gamma (65 - 100 Hz), ripple (100 - 250 Hz), and fast ripple (250 - 600 Hz) frequency ranges...
December 2017: Current Opinion in Biomedical Engineering
Eline R Kupers, Helena X Wang, Kaoru Amano, Kendrick N Kay, David J Heeger, Jonathan Winawer
Currently, non-invasive methods for studying the human brain do not routinely and reliably measure spike-rate-dependent signals, independent of responses such as hemodynamic coupling (fMRI) and subthreshold neuronal synchrony (oscillations and event-related potentials). In contrast, invasive methods-microelectrode recordings and electrocorticography (ECoG)-have recently measured broadband power elevation in field potentials (~50-200 Hz) as a proxy for locally averaged spike rates. Here, we sought to detect and quantify stimulus-related broadband responses using magnetoencephalography (MEG)...
2018: PloS One
Christie L Glau, Thomas W Conlon, Adam S Himebauch, Donald L Boyer, Samuel A Rosenblatt, Akira Nishisaki
High-frequency oscillatory ventilation (HFOV) is a mode of mechanical ventilation used in severe pediatric respiratory failure. Thoracic ultrasound (US) is a powerful tool for diagnosing acute pathophysiologic conditions during spontaneous respiration and conventional noninvasive and invasive mechanical ventilation. High-frequency oscillatory ventilation differs from conventional modes of ventilation in that it does not primarily use bulk flow delivery for gas exchange but, rather, a number of alternative mechanisms as the result of pressure variations oscillating around a constant distending pressure...
March 12, 2018: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
Marcel Heers, Moritz Helias, Tanguy Hedrich, Matthias Dümpelmann, Andreas Schulze-Bonhage, Tonio Ball
The foremost aim of presurgical epilepsy evaluation is the delineation of the seizure onset zone (SOZ). There is increasing evidence that fast epileptic activity (FEA, 14-250 Hz) occurring interictally, i.e. between seizures, is predominantly localized within the SOZ. Currently it is unknown, which frequency band of FEA performs best in identifying the SOZ, although prior studies suggest highest concordance of spectral changes with the SOZ for high frequency changes. We suspected that FEA reflects dampened oscillations in local cortical excitatory-inhibitory neural networks, and that interictal FEA in the SOZ is a consequence of reduced oscillatory damping...
2018: NeuroImage: Clinical
C Cuello-Oderiz, N von Ellenrieder, R Sankhe, A Olivier, J Hall, F Dubeau, J Gotman
OBJECTIVES: There are different neurophysiological markers of the Epileptogenic Zone (EZ), but their sensitivity and specificity for the EZ is not known in Focal Cortical Dysplasia (FCD) patients. METHODS: We studied patients with FCD who underwent stereoelectroencephalography (SEEG) and surgery. We marked in the SEEG: (a) typical and atypical interictal epileptiform patterns, (b) ictal onset patterns, and (c) rates of ripples (80-250 Hz) and fast ripples (FRs) (>250 Hz)...
February 22, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Morgan Mercredi, Melanie Martin
OBJECT: Recent advances have allowed oscillating gradient (OG) diffusion MRI to infer the sizes of micron-scale axon diameters. Here the effects on the precision of the inferred diameters are studied when reducing the number of images collected to reduce imaging time for clinical feasibility. MATERIALS AND METHODS: Monte Carlo simulations of cosine OG sequences (50-1000 Hz) using a two-compartment model on a parallel cylinder (diameters 1-5 μm) geometry were conducted...
March 7, 2018: Magma
Matthias Deliano, Michael G K Brunk, Mohamed El-Tabbal, Maria M Zempeltzi, Max F K Happel, Frank W Ohl
Cortical release of the neurotransmitter dopamine has been implied in adapting cortical processing with respect to various functions including coding of stimulus salience, expectancy, error prediction, behavioral relevance, and learning. Dopamine agonists have been shown to modulate recurrent cortico-thalamic feedback, and should therefore also affect synchronization and amplitude of thalamo-cortical oscillations. In this study we have used multitaper spectral and time-frequency analysis of stimulus-evoked and spontaneous current source density patterns in primary auditory cortex of Mongolian gerbils to characterize dopaminergic neuromodulation of the oscillatory structure of current sources and sinks...
March 7, 2018: European Journal of Neuroscience
Avik Dutt, Chaitanya Joshi, Xingchen Ji, Jaime Cardenas, Yoshitomo Okawachi, Kevin Luke, Alexander L Gaeta, Michal Lipson
Dual-comb spectroscopy is a powerful technique for real-time, broadband optical sampling of molecular spectra, which requires no moving components. Recent developments with microresonator-based platforms have enabled frequency combs at the chip scale. However, the need to precisely match the resonance wavelengths of distinct high quality-factor microcavities has hindered the development of on-chip dual combs. We report the simultaneous generation of two microresonator combs on the same chip from a single laser, drastically reducing experimental complexity...
March 2018: Science Advances
Lin Li, Mayur Patel, Joyel Almajano, Jerome Engel, Anatol Bragin
The current study aimed to investigate the spatial and temporal patterns of high-frequency oscillations (HFOs) in the intra-/extrahippocampal areas during epileptogenesis. Local field potentials were bilaterally recorded from hippocampus (CA1), thalamus, motor cortex, and prefrontal cortex in 13 rats before and after intrahippocampal kainic acid (KA) lesions. HFOs in the ripple (100-200 Hz) and fast ripple (250-500 Hz) ranges were detected and their rates were computed during different time periods (1-5 weeks) after KA-induced status epilepticus (SE)...
March 6, 2018: Epilepsia
Catherine L Tegeler, Lee Gerdes, Hossam A Shaltout, Jared F Cook, Sean L Simpson, Sung W Lee, Charles H Tegeler
BACKGROUND: Military-related post-traumatic stress (PTS) is associated with numerous symptom clusters and diminished autonomic cardiovascular regulation. High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM®) is a noninvasive, closed-loop, allostatic, acoustic stimulation neurotechnology that produces real-time translation of dominant brain frequencies into audible tones of variable pitch and timing to support the auto-calibration of neural oscillations. We report clinical, autonomic, and functional effects after the use of HIRREM® for symptoms of military-related PTS...
December 22, 2017: Military Medical Research
Antonello Nicolini, Bruna Grecchi, Maura Ferrari-Bravo, Cornelius Barlascini
Purpose: Chest physiotherapy is an important tool in the treatment of COPD. Intrapulmonary percussive ventilation (IPV) and high-frequency chest wall oscillation (HFCWO) are techniques designed to create a global percussion of the lung which removes secretions and probably clears the peripheral bronchial tree. We tested the hypothesis that adding IPV or HFCWO to the best pharmacological therapy (PT) may provide additional clinical benefit over chest physiotherapy in patients with severe COPD...
2018: International Journal of Chronic Obstructive Pulmonary Disease
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