795 results match your criteria: "City College of the City University of New York[Affiliation]"

Shubnikov de Haas resistance oscillations of highly mobile two dimensional helical electrons propagating on a conducting surface of strained HgTe 3D topological insulator are studied in magnetic fields B tilted by angle θ from the normal to the conducting layer. Strong decrease of oscillation amplitude A is observed with the tilt: [Formula: see text], where ξ is a constant. Evolution of the oscillations with temperature T shows that the parameter [Formula: see text] contains two terms: [Formula: see text].

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Concurrent Imaging of Markers of Current Flow and Neurophysiological Changes During tDCS.

Front Neurosci

April 2020

Laboratory of FMRI Technology, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States.

Despite being a popular neuromodulation technique, clinical translation of transcranial direct current stimulation (tDCS) is hampered by variable responses observed within treatment cohorts. Addressing this challenge has been difficult due to the lack of an effective means of mapping the neuromodulatory electromagnetic fields together with the brain's response. In this study, we present a novel imaging technique that provides the capability of concurrently mapping markers of tDCS currents, as well as the brain's response to tDCS.

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Demonstration of a quantized acoustic octupole topological insulator.

Nat Commun

April 2020

Department of Electrical Engineering, Grove School of Engineering, City College of the City University of New York, 140th Street and Convent Avenue, New York, NY, 10031, USA.

Recently introduced quantized multipole topological insulators (QMTIs) reveal new types of gapped boundary states, which themselves represent lower-dimensional topological phases and host symmetry protected zero-dimensional corner states. Inspired by these predictions, tremendous efforts have been devoted to the experimental observation of quantized quadrupole topological phase. However, due to stringent requirements of anti-commuting reflection symmetries, it is challenging to achieve higher-order quantized multipole moments, such as octupole moments, in a three-dimensional structure.

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Pre-atherosclerotic flow and oncotically active solute transport across the arterial endothelium.

J Theor Biol

August 2020

Department of Chemical Engineering, City College of the City University of New York, NY, United States; Department of Medicine, College of Physicians and Surgeons, Columbia University, NY, United States. Electronic address:

Atherosclerosis starts with transmural (transwall) pressure-driven advective transport of blood-borne low-density lipoprotein (LDL) cholesterol across rare endothelial cell (EC) monolayer leaks into the arterial subendothelial intima (SI) wall layer where they can spread, bind to extracellular matrix and seed lesions. The local SI LDL concentration, which governs LDL's binding kinetics, depends on the overall diluting transmural liquid flow. Transmural pressures typically compress the SI at physiological pressures, which keeps this flow low.

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Demonstration of a third-order hierarchy of topological states in a three-dimensional acoustic metamaterial.

Sci Adv

March 2020

Department of Electrical Engineering, Grove School of Engineering, City College of the City University of New York, 140th Street and Convent Avenue, New York, NY 10031, USA.

Classical wave systems have constituted an excellent platform for emulating complex quantum phenomena, such as demonstrating topological phenomena in photonics and acoustics. Recently, a new class of topological states localized in more than one dimension of a -dimensional system, referred to as higher-order topological (HOT) states, has been reported, offering an even more versatile platform to confine and control classical radiation and mechanical motion. Here, we design and experimentally study a 3D topological acoustic metamaterial supporting third-order (0D) topological corner states along with second-order (1D) edge states and first-order (2D) surface states within the same topological bandgap, thus establishing a full hierarchy of nontrivial bulk polarization-induced states in three dimensions.

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This paper presents the use of a commercial quartz crystal microbalance (QCM) to investigate live-cell activity in water-based toxic solutions. The QCM used in this research has a resonant frequency of 10 MHz and consists of an AT-cut quartz crystal with gold electrodes on both sides. This QCM was transformed into a functional biosensor by integrating with polydimethylsiloxane culturing chambers.

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Severe brain injuries can lead to long-lasting disorders of consciousness (DoC) such as vegetative state/unresponsive wakefulness syndrome (VS/UWS) or minimally conscious state (MCS). While behavioral assessment remains the gold standard to determine conscious state, EEG has proven to be a promising complementary tool to monitor the effect of new therapeutics. Encouraging results have been obtained with invasive electrical stimulation of the brain, and recent studies identified transcranial direct current stimulation (tDCS) as an effective approach in randomized controlled trials.

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Interpretations are considered to be an important active ingredient in psychodynamic treatment. Research shows mixed results regarding the empirical utility of interpretations, and continuing efforts are needed to investigate what makes interpretations helpful and effective. Our aim was to examine what allows an interpretation to facilitate growth, promoting the flourishing of the patient.

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Chemically active particles achieve motility without external forces and torques ("self-propulsion") due to catalytic chemical reactions at their surfaces, which change the chemical composition of the surrounding solution (called "chemical field") and induce hydrodynamic flow of the solution. By coupling the distortions of these fields back to its motion, a chemically active particle experiences an effective interaction with confining surfaces. This coupling can lead to a rich behavior, such as the occurrence of wall-bound steady states of "sliding".

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Behavioral and anatomical sex-related differences have been traditionally found in decision-making processes assessed by Iowa Gambling Task (IGT). So far, the administration of transcranial direct current stimulation (tDCS) over orbitofrontal regions has shown an enhancing effect over decision-making. However, it is unknown whether there is a sex-dependent effect of stimulation in decision-making, a key question considering previous differences between men and women in IGT and the influence of individual differences in tDCS.

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Objective: It has been asserted that burnout-a condition ascribed to unresolvable job stress-should not be mistaken for a depressive syndrome. In this confirmatory factor analytic study, the validity of this assertion was examined.

Methods: Five samples of employed individuals, recruited in Switzerland and France, were mobilized for this study (N = 3,113).

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Hyperbolic Sound Propagation over Nonlocal Acoustic Metasurfaces.

Phys Rev Lett

December 2019

Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.

Hyperbolic metasurfaces, supporting extreme anisotropy of the surface impedance tensor, have recently been explored in nanophotonic systems for robust diffractionless propagation over a surface, offering interesting opportunities for subdiffraction imaging and enhanced Purcell emission. In acoustics, due to the longitudinal nature of sound transport in fluids, these phenomena are forbidden by symmetry, requiring the acoustic surface impedance to be inherently isotropic. Here we show that nonlocalities produced by strong coupling between neighboring impedance elements enable extreme anisotropic responses for sound traveling over a surface, supporting negative phase and energy velocities, as well as hyperbolic propagation for acoustic surface waves.

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tDCS has been used to treat various brain disorders and its mechanism of action (MoA) was found to be neuronal polarization. Since the blood-brain barrier (BBB) tightly regulates the neuronal microenvironment, we hypothesized that another MoA of tDCS is direct vascular activation by modulating the BBB structures to increase its permeability (P). To test this hypothesis, we used high resolution multiphoton microscopy to determine P of the cerebral microvessels in rat brain.

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Understanding and reducing variability of response to transcranial direct current stimulation (tDCS) requires measuring what factors predetermine sensitivity to tDCS and tracking individual response to tDCS. Human trials, animal models, and computational models suggest structural traits and functional states of neural systems are the major sources of this variance. There are 118 published tDCS studies (up to October 1, 2018) that used fMRI as a proxy measure of neural activation to answer mechanistic, predictive, and localization questions about how brain activity is modulated by tDCS.

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All-optical reconfigurable chiral meta-molecules.

Mater Today (Kidlington)

May 2019

Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.

Chirality is a ubiquitous phenomenon in the natural world. Many biomolecules without inversion symmetry such as amino acids and sugars are chiral molecules. Measuring and controlling molecular chirality at a high precision down to the atomic scale are highly desired in physics, chemistry, biology, and medicine, however, have remained challenging.

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Beyond Chu's Limit with Floquet Impedance Matching.

Phys Rev Lett

October 2019

Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, USA.

Chu's limit determines the minimum radiation quality factor Q of an electrically small resonator, and hence its maximum operational bandwidth, which is inversely proportional to its volume. This bound imposes severe restrictions in several areas of technology, from wireless communications to nanophotonics and metamaterials. We show that a suitably tailored temporal modulation of the matching network, combined with proper detuning of the feeding impedance, can overcome this limit and enable radiation over broader bandwidths, which scale as 1/sqrt[Q], ensuring at the same time stability.

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Recent longitudinal neuroimaging studies in patients with electroconvulsive therapy (ECT) suggest local effects of electric stimulation (lateralized) occur in tandem with global seizure activity (generalized). We used electric field (EF) modeling in 151 ECT treated patients with depression to determine the regional relationships between EF, unbiased longitudinal volume change, and antidepressant response across 85 brain regions. The majority of regional volumes increased significantly, and volumetric changes correlated with regional electric field (t = 3.

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Coherent virtual absorption of elastodynamic waves.

Sci Adv

August 2019

Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA.

Absorbers suppress reflection and scattering of an incident wave by dissipating its energy into heat. As material absorption goes to zero, the energy impinging on an object is necessarily transmitted or scattered away. Specific forms of temporal modulation of the impinging signal can suppress wave scattering and transmission in the transient regime, mimicking the response of a perfect absorber without relying on material loss.

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Nonreciprocal Willis Coupling in Zero-Index Moving Media.

Phys Rev Lett

August 2019

Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.

Mechanical motion can break the symmetry in which sound travels in a medium, but significant nonreciprocity is typically achieved only for large motion speeds. We combine moving media with zero-index acoustic propagation, yielding extreme nonreciprocity and induced bianisotropy for modest applied speeds. The metamaterial is formed by an array of waveguides loaded by Helmholtz resonators, and it exhibits opposite signs of the refractive index sustained by asymmetric Willis coupling for propagation in opposite directions.

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This special section in Psychological Trauma: Theory, Research, Practice, and Policy: "Religion and Spirituality in the Context of Disaster," demonstrates the heterogeneity and complexities of religion as a variable of psychological resilience in response to disaster. Research from hurricane, flood, and mass shooting disasters are reported. So too is the development of a new measure of disaster response.

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Prosaccades are saccadic eye movements made reflexively in response to the sudden appearance of visual stimuli, whereas antisaccades are saccades that are directed to a location opposite a stimulus. Bibi and Edelman (Bibi R, Edelman JA. 102: 3101-3110, 2009) demonstrated that decreases in reaction time resulting from training prosaccades along one spatial axis (horizontal or vertical) could transfer to prosaccades made along the other axis.

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Message Framing and the Willingness to Pursue Behavioral Therapy: A Study of People With Migraine.

J Neuropsychiatry Clin Neurosci

November 2020

The Department of Psychology, City College of the City University of New York (Jalloh); the Department of Neurology, Columbia University Medical Center, New York (Begasse de Dhaem); the Department of Neurology, Yeshiva University Albert Einstein College of Medicine, Bronx, N.Y. (Seng); and the Department of Neurology and Department of Population Health, New York University (Minen).

Objective: Behavioral treatments for migraine prevention are safe and effective but underutilized in migraine management. Health message framing may be helpful in guiding patients with treatment decision making. The authors assessed associations between message framing and the willingness to seek migraine behavioral treatment among persons with a diagnosis of migraine headache.

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We demonstrate an optomechanical platform where optical mode conversion mediated by mechanical motion enables the arbitrary tailoring of polarization states of propagating light fields. Optomechanical interactions are realized in a Fabry-Pérot resonator, which naturally supports two polarization-degenerate states while an optical control field induces rotational symmetry breaking. Applying such principles, the entire Poincaré sphere is spanned by just optical control of the driving field, realizing reciprocal and nonreciprocal optomechanically induced birefringence for linearly polarized and circularly polarized control driving.

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Transcranial electrical stimulation nomenclature.

Brain Stimul

February 2020

Department of Psychiatry & Behavioral Sciences, Department of Biomedical Engineering, Department of Electrical & Computer Engineering, Department of Neurosurgery, Duke University, Durham, NC, USA.

Transcranial electrical stimulation (tES) aims to alter brain function non-invasively by applying current to electrodes on the scalp. Decades of research and technological advancement are associated with a growing diversity of tES methods and the associated nomenclature for describing these methods. Whether intended to produce a specific response so the brain can be studied or lead to a more enduring change in behavior (e.

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Active acoustic switches using two-dimensional granular crystals.

Phys Rev E

June 2019

Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA.

We employ numerical simulations to study active transistor-like switches made from two-dimensional (2D) granular crystals containing two types of grains with the same size but different masses. We tune the mass contrast and arrangement of the grains to maximize the width of the frequency band gap in the device. The input signal is applied to a single grain on one side of the device, and the output signal is measured from another grain on the other side of the device.

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