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https://www.readbyqxmd.com/read/28218853/new-information-on-the-hydrophobic-interaction-revealed-by-frequency-modulation-afm
#1
Itai Schlesinger, Uri Sivan
Using an ultra-high resolution AFM operated in frequency modulation mode we extend existing measurements of the force acting between hydrophobic surfaces immersed in water in three essential ways. (1) The measurement range, which was previously limited to distances longer than 2-3 nanometers, is extended to cover all distances, down to contact. The measurements disclose that the long-range attraction observed also by conventional techniques, turns at distances shorter than 1-2 nanometers into pronounced repulsion...
February 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28212162/volume-and-pressure-delivery-during-pediatric-high-frequency-oscillatory-ventilation
#2
Ronald Wong, Timothy Deakers, Justin Hotz, Robinder G Khemani, Patrick A Ross, Christopher J Newth
OBJECTIVE: Identify variables independently associated with delivered tidal volume (VT) and measured mean airway pressure during high-frequency oscillatory ventilation across the range of pediatric endotracheal tube sizes. DESIGN: In vitro study. SETTING: Research laboratory. INTERVENTIONS: An in vitro bench model of the intubated pediatric respiratory system during high-frequency oscillatory ventilation was used to obtain delivered VT and mean airway pressure (in the distal lung) for various endotracheal tube sizes...
February 16, 2017: Pediatric Critical Care Medicine
https://www.readbyqxmd.com/read/28208468/colloidal-polycrystalline-monolayers-under-oscillatory-shear
#3
Ivo Buttinoni, Mathias Steinacher, Hendrik Th Spanke, Juho Pokki, Severin Bahmann, Bradley Nelson, Giuseppe Foffi, Lucio Isa
In this paper we probe the structural response to oscillatory shear deformations of polycrystalline monolayers of soft repulsive colloids with varying area fraction over a broad range of frequencies and amplitudes. The particles are confined at a fluid interface, sheared using a magnetic microdisk, and imaged through optical microscopy. The structural and mechanical response of soft materials is highly dependent on their microstructure. If crystals are well understood and deform through the creation and mobilization of specific defects, the situation is much more complex for disordered jammed materials, where identifying structural motifs defining plastically rearranging regions remains an elusive task...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28193169/eeg-correlates-of-working-memory-performance-in-females
#4
Yuri G Pavlov, Boris Kotchoubey
BACKGROUND: The study investigates oscillatory brain activity during working memory (WM) tasks. The tasks employed varied in two dimensions. First, they differed in complexity from average to highly demanding. Second, we used two types of tasks, which required either only retention of stimulus set or retention and manipulation of the content. We expected to reveal EEG correlates of temporary storage and central executive components of WM and to assess their contribution to individual differences...
February 13, 2017: BMC Neuroscience
https://www.readbyqxmd.com/read/28192762/neural-mass-models-describing-possible-origin-of-the-excessive-beta-oscillations-correlated-with-parkinsonian-state
#5
Chen Liu, Yulin Zhu, Fei Liu, Jiang Wang, Huiyan Li, Bin Deng, Chris Fietkiewicz, Kenneth A Loparo
In Parkinson's disease, the enhanced beta rhythm is closely associated with akinesia/bradykinesia and rigidity. An increase in beta oscillations (12-35 Hz) within the basal ganglia (BG) nuclei does not proliferate throughout the cortico-basal ganglia loop in uniform fashion; rather it can be subdivided into two distinct frequency bands, i.e. the lower beta (12-20 Hz) and upper beta (21-35 Hz). A computational model of the excitatory and inhibitory neural network that focuses on the population properties is proposed to explore the mechanism underlying the pathological beta oscillations...
January 30, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/28192459/differential-effects-of-ongoing-eeg-beta-and-theta-power-on-memory-formation
#6
Sebastian Scholz, Signe Luisa Schneider, Michael Rose
Recently, elevated ongoing pre-stimulus beta power (13-17 Hz) at encoding has been associated with subsequent memory formation for visual stimulus material. It is unclear whether this activity is merely specific to visual processing or whether it reflects a state facilitating general memory formation, independent of stimulus modality. To answer that question, the present study investigated the relationship between neural pre-stimulus oscillations and verbal memory formation in different sensory modalities. For that purpose, a within-subject design was employed to explore differences between successful and failed memory formation in the visual and auditory modality...
2017: PloS One
https://www.readbyqxmd.com/read/28192158/relating-emulsion-stability-to-interfacial-properties-for-pharmaceutical-emulsions-stabilized-by-pluronic-f68-surfactant
#7
Kristin Conrad Powell, Robert Damitz, Anuj Chauhan
We explore mechanisms of emulsion stability for several systems using Pluronic F68 and a range of oils commonly used in pharmaceutics and cosmetics. We report measurements of dynamic emulsion drop size, zeta potential, and creaming time, as well as dynamic interfacial tension and interfacial viscoelasticity. Experiments show that with 1wt% Pluronic F68, soybean oil emulsions were the most stable with no creaming over six months, followed by isopropyl myristate, octanoic acid, and then ethyl butyrate. The eventual destabilization occurred due to the rising of large drops which formed through Ostwald ripening and coalescence...
February 9, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28184188/stimulus-phase-locking-of-cortical-oscillations-for-rhythmic-tone-sequences-in-rats
#8
Takahiro Noda, Tomoki Amemiya, Tomoyo I Shiramatsu, Hirokazu Takahashi
Humans can rapidly detect regular patterns (i.e., within few cycles) without any special attention to the acoustic environment. This suggests that human sensory systems are equipped with a powerful mechanism for automatically predicting forthcoming stimuli to detect regularity. It has recently been hypothesized that the neural basis of sensory predictions exists for not only what happens (predictive coding) but also when a particular stimulus occurs (predictive timing). Here, we hypothesize that the phases of neural oscillations are critical in predictive timing, and these oscillations are modulated in a band-specific manner when acoustic patterns become predictable, i...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/28176756/amygdala-hippocampal-dynamics-during-salient-information-processing
#9
Jie Zheng, Kristopher L Anderson, Stephanie L Leal, Avgusta Shestyuk, Gultekin Gulsen, Lilit Mnatsakanyan, Sumeet Vadera, Frank P K Hsu, Michael A Yassa, Robert T Knight, Jack J Lin
Recognizing motivationally salient information is critical to guiding behaviour. The amygdala and hippocampus are thought to support this operation, but the circuit-level mechanism of this interaction is unclear. We used direct recordings in the amygdala and hippocampus from human epilepsy patients to examine oscillatory activity during processing of fearful faces compared with neutral landscapes. We report high gamma (70-180 Hz) activation for fearful faces with earlier stimulus evoked onset in the amygdala compared with the hippocampus...
February 8, 2017: Nature Communications
https://www.readbyqxmd.com/read/28157820/high-frequency-oscillatory-ventilation-still-a-role
#10
Jensen Ng, Niall D Ferguson
PURPOSE OF REVIEW: In light of emerging data from clinical trials, the place of high-frequency oscillatory ventilation (HFOV) in the management of acute respiratory distress syndrome (ARDS) is uncertain. This review provides an overview of these new clinical data and also explores new areas of investigation for HFOV in adults. RECENT FINDINGS: While prior meta-analyses suggested benefit for HFOV, updated systematic reviews published this year, which include two large recent clinical trials, now show no statistically significant impact of HFOV on mortality in adults with ARDS...
February 2, 2017: Current Opinion in Critical Care
https://www.readbyqxmd.com/read/28140398/theta-and-high-beta-networks-for-feedback-processing-a-simultaneous-eeg-fmri-study-in-healthy-male-subjects
#11
C Andreou, H Frielinghaus, J Rauh, M Mußmann, S Vauth, P Braun, G Leicht, C Mulert
The reward system is important in assessing outcomes to guide behavior. To achieve these purposes, its core components interact with several brain areas involved in cognitive and emotional processing. A key mechanism suggested to subserve these interactions is oscillatory activity, with a prominent role of theta and high-beta oscillations. The present study used single-trial coupling of simultaneously recorded electroencephalography and functional magnetic resonance imaging data to investigate networks associated with oscillatory responses to feedback during a two-choice gambling task in healthy male participants (n=19)...
January 31, 2017: Translational Psychiatry
https://www.readbyqxmd.com/read/28137968/two-independent-frontal-midline-theta-oscillations-during-conflict-detection-and-adaptation-in-a-simon-type-manual-reaching-task
#12
Thomas Töllner, Yijun Wang, Scott Makeig, Hermann J Müller, Tzyy-Ping Jung, Klaus Gramann
: One of the most firmly established factors determining the speed of human behavioral responses towards action-critical stimuli is the spatial correspondence between the stimulus and response locations. If both locations match, the time taken for response production is markedly reduced relative to when they mismatch-a phenomenon called Simon effect. While there is a consensus that this stimulus-response (S-R) conflict is associated with brief (4-7 Hz) frontal midline theta (fmθ) complexes generated in medial frontal cortex (MFC), it remains controversial (i) whether there are multiple, simultaneously active theta generator areas in the MFC that commonly give rise to conflict-related fmθ complexes; and if so, (ii) whether they are all related to the resolution of conflicting task information...
January 30, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28125658/alterations-in-neural-control-of-constant-isometric-contraction-with-the-size-of-error-feedback
#13
Ing-Shiou Hwang, Yen-Ting Lin, Wei-Min Huang, Zong-Ru Yang, Chia-Ling Hu, Yi-Ching Chen
Discharge patterns from a population of motor units (MUs) were estimated with multi-channel surface electromyogram and signal processing techniques to investigate parametric differences in low-frequency force fluctuations, MU discharges, and force-discharge relation during static force-tracking with varying sizes of execution error presented via visual feedback. Fourteen healthy adults produced isometric force at 10% of maximal voluntary contraction through index abduction under three visual conditions that scaled execution errors with different amplification factors...
2017: PloS One
https://www.readbyqxmd.com/read/28113403/a-biochemical-oscillator-using-excitatory-molecules-for-nanonetworks
#14
Ethungshan Shitiri, Ho-Shin Cho
For nanonetworks to be able to achieve large-scale functionality, such as to respond collectively to a trigger, synchrony between nanomachines is essential. However, to facilitate synchronization, some sort of physical clocking mechanism is required, such as the oscillators driven by auto-inhibitory molecules or by auto-inducing molecules. In this study, taking inspiration from the widely studied biological oscillatory phenomena called Calcium (Ca2+) oscillations, we undertake a different approach to design an oscillator...
October 18, 2016: IEEE Transactions on Nanobioscience
https://www.readbyqxmd.com/read/28096571/acute-respiratory-failure-and-mechanical-ventilation-in-pregnant-patient-a-narrative-review-of-literature
#15
REVIEW
Pradeep Kumar Bhatia, Ghansham Biyani, Sadik Mohammed, Priyanka Sethi, Pooja Bihani
Physiological changes of pregnancy imposes higher risk of acute respiratory failure (ARF) with even a slight insult and remains an important cause of maternal and fetal morbidity and mortality. Although pregnant women have different respiratory physiology and different causes of ARF, guidelines specific to ventilatory settings, goals of oxygenation and weaning process could not be framed due to lack of large-scale randomized controlled trials. During the 2009 H1N1 pandemic, pregnant women had higher morbidity and mortality compared to nonpregnant women...
October 2016: Journal of Anaesthesiology, Clinical Pharmacology
https://www.readbyqxmd.com/read/28069165/on-the-quantification-and-visualization-of-transient-periodic-instabilities-in-pulsatile-flows
#16
Muhammad Owais Khan, Christophe Chnafa, Diego Gallo, Filippo Molinari, Umberto Morbiducci, David A Steinman, Kristian Valen-Sendstad
Turbulent-like flows without cycle-to-cycle variations are more frequently being reported in studies of cardiovascular flows. The associated stimuli might be of mechanobiological relevance, but how to quantify them objectively is not obvious. Classical Reynolds decomposition, where the flow is separated into mean and fluctuating velocity components, is not applicable as the phase-average is zero. We therefore expanded on established techniques and present the idea, analogous to Reynolds decomposition, to decompose a flow with transient instabilities into low- versus high frequency components, respectively, to discriminate flow instabilities from the underlying cardiac pulsatility...
December 31, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/28053151/optimized-temporal-pattern-of-brain-stimulation-designed-by-computational-evolution
#17
David T Brocker, Brandon D Swan, Rosa Q So, Dennis A Turner, Robert E Gross, Warren M Grill
Brain stimulation is a promising therapy for several neurological disorders, including Parkinson's disease. Stimulation parameters are selected empirically and are limited to the frequency and intensity of stimulation. We varied the temporal pattern of deep brain stimulation to ameliorate symptoms in a parkinsonian animal model and in humans with Parkinson's disease. We used model-based computational evolution to optimize the stimulation pattern. The optimized pattern produced symptom relief comparable to that from standard high-frequency stimulation (a constant rate of 130 or 185 Hz) and outperformed frequency-matched standard stimulation in a parkinsonian rat model and in patients...
January 4, 2017: Science Translational Medicine
https://www.readbyqxmd.com/read/28041911/disinhibition-of-the-intergeniculate-leaflet-network-in-the-wag-rij-rat-model-of-absence-epilepsy
#18
Lukasz Chrobok, Katarzyna Palus, Jagoda Stanislawa Jeczmien-Lazur, Anna Chrzanowska, Mariusz Kepczynski, Marian Henryk Lewandowski
The intergeniculate leaflet (IGL) of the thalamus is a retinorecipient structure implicated in orchestrating circadian rhythmicity. The IGL network is highly GABAergic and consists mainly of neuropeptide Y-synthesising and enkephalinergic neurons. A high density of GFAP-immunoreactive astrocytes has been observed in the IGL, with a probable function in guarding neuronal inhibition. Interestingly, putatively enkephalinergic IGL neurons generate action potentials with an infra-slow oscillatory (ISO) pattern in vivo in urethane anesthetised Wistar rats, under light-on conditions only...
December 30, 2016: Experimental Neurology
https://www.readbyqxmd.com/read/28040004/oscillatory-fluid-flow-in-deformable-tubes-implications-for-pore-scale-hydromechanics-from-comparing-experimental-observations-with-theoretical-predictions
#19
Patrick Kurzeja, Holger Steeb, Marc A Strutz, Jörg Renner
Oscillatory flow of four fluids (air, water, two aqueous sodium-tungstate solutions) was excited at frequencies up to 250 Hz in tubes of two materials (steel, silicone) covering a wide range in length, diameter, and thickness. The hydrodynamical response was characterized by phase shift and amplitude ratio between pressures in an upstream (pressure excitation) and a downstream reservoir connected by the tubes. The resulting standing flow waves reflect viscosity-controlled diffusive behavior and inertia-controlled wave behavior for oscillation frequencies relatively low and high compared to Biot's critical frequency, respectively...
December 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28031220/pathological-ponto-cerebello-thalamo-cortical-activations-in-primary-orthostatic-tremor-during-lying-and-stance
#20
Florian Schöberl, Katharina Feil, Guoming Xiong, Peter Bartenstein, Christian la Fougére, Klaus Jahn, Thomas Brandt, Michael Strupp, Marianne Dieterich, Andreas Zwergal
Primary orthostatic tremor is a rare neurological disease characterized mainly by a high frequency tremor of the legs while standing. The aim of this study was to identify the common core structures of the oscillatory circuit in orthostatic tremor and how it is modulated by changes of body position. Ten patients with orthostatic tremor and 10 healthy age-matched control subjects underwent a standardized neurological and neuro-ophthalmological examination including electromyographic and posturographic recordings...
January 2017: Brain: a Journal of Neurology
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