831 results match your criteria: "IBM T.J Watson Research Center[Affiliation]"

Background: Standard cine-cardiac magnetic resonance (CMR) imaging is commonly used to evaluate cardiac structure, geometry and function. Prior studies have shown that automated segmentation via partial voxel interpolation (PVI) accurately quantifies phantom-based cardiac chamber volumes and necropsy left ventricular myocardial mass. Despite this, the applicability and usefulness of PVI in the determination of physiologic parameters of the aorta such as aortic stiffness has yet to be investigated.

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OpenRBC: A Fast Simulator of Red Blood Cells at Protein Resolution.

Biophys J

May 2017

Division of Applied Mathematics, Brown University, Providence, Rhode Island. Electronic address:

We present OpenRBC, a coarse-grained molecular dynamics code, which is capable of performing an unprecedented in silico experiment-simulating an entire mammal red blood cell lipid bilayer and cytoskeleton as modeled by multiple millions of mesoscopic particles-using a single shared memory commodity workstation. To achieve this, we invented an adaptive spatial-searching algorithm to accelerate the computation of short-range pairwise interactions in an extremely sparse three-dimensional space. The algorithm is based on a Voronoi partitioning of the point cloud of coarse-grained particles, and is continuously updated over the course of the simulation.

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Low-energy electron potentiometry.

Ultramicroscopy

October 2017

Huygens-Kamerlingh Onnes Laboratorium, Leiden University, NL-2300 RA Leiden, P.O. Box 9504, Netherlands.

Article Synopsis
  • Charge transport in systems often depends on local features rather than a single global resistance value, highlighting the need for techniques that map local electronic potentials.
  • A new potentiometry method using low-energy electron microscopy (LEEM) has been developed, which is fast, has a large field of view, and is non-invasive, but is limited by the availability of characteristic reflectivity features in some materials.
  • The paper introduces an alternative low-energy electron potentiometry (LEEP) method based on a universal mirror mode transition, which is effective for a wider range of materials, and demonstrates its application in analyzing electrostatic surface potential variations and the Schottky effect in metal-semiconductor junctions.
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Aberrant Network Activity in Schizophrenia.

Trends Neurosci

June 2017

Hull York Medical School, University of York, Heslington, YO10 5DD, UK. Electronic address:

Brain dynamic changes associated with schizophrenia are largely equivocal, with interpretation complicated by many factors, such as the presence of therapeutic agents and the complex nature of the syndrome itself. Evidence for a brain-wide change in individual network oscillations, shared by all patients, is largely equivocal, but stronger for lower (delta) than for higher (gamma) bands. However, region-specific changes in rhythms across multiple, interdependent, nested frequencies may correlate better with pathology.

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In recent years, antipsychotic medications have increasingly been used in pediatric and geriatric populations, despite the fact that many of these drugs were approved based on clinical trials in adult patients only. Preliminary studies have shown that the "off-label" use of these drugs in pediatric and geriatric populations may result in adverse events not found in adults. In this study, we utilized the large-scale U.

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Combinations of sub 1 μm absorber films with high-work-function back surface contact layers are expected to induce large enough internal fields to overcome adverse effects of bulk defects on thin-film photovoltaic performance, particularly in earth-abundant kesterites. However, there are numerous experimental challenges involving back surface engineering, which includes exfoliation, thinning, and contact layer optimization. In the present study, a unique combination of nanocharacterization tools, including nano-Auger, Kelvin probe force microscopy (KPFM), and cryogenic focused ion beam measurements, are employed to gauge the possibility of surface potential modification in the absorber back surface via direct deposition of high-work-function metal oxides on exfoliated surfaces.

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Engineering monolayer poration for rapid exfoliation of microbial membranes.

Chem Sci

February 2017

National Physical Laboratory , Teddington , Middlesex TW11 0LW , UK . Email:

The spread of bacterial resistance to traditional antibiotics continues to stimulate the search for alternative antimicrobial strategies. All forms of life, from bacteria to humans, are postulated to rely on a fundamental host defense mechanism, which exploits the formation of open pores in microbial phospholipid bilayers. Here we predict that transmembrane poration is not necessary for antimicrobial activity and reveal a distinct poration mechanism that targets the outer leaflet of phospholipid bilayers.

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In recent years, Cu ZnSn(S,Se) (CZTSSe) materials have enabled important progress in associated thin-film photovoltaic (PV) technology, while avoiding scarce and/or toxic metals; however, cationic disorder and associated band tailing fundamentally limit device performance. Cu BaSnS (CBTS) has recently been proposed as a prospective alternative large bandgap (~2 eV), environmentally friendly PV material, with ~2% power conversion efficiency (PCE) already demonstrated in corresponding devices. In this study, a two-step process (i.

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Graphene epitaxy on the Si face of a SiC wafer offers monolayer graphene with unique crystal orientation at the wafer-scale. However, due to carrier scattering near vicinal steps and excess bilayer stripes, the size of electrically uniform domains is limited to the width of the terraces extending up to a few microns. Nevertheless, the origin of carrier scattering at the SiC vicinal steps has not been clarified so far.

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Computational modeling of sketch understanding is interesting both scientifically and for creating systems that interact with people more naturally. Scientifically, understanding sketches requires modeling aspects of visual processing, spatial representations, and conceptual knowledge in an integrated way. Software that can understand sketches is starting to be used in classrooms, and it could have a potentially revolutionary impact as the models and technologies become more advanced.

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Barrier Crossing in Escherichia coli Chemotaxis.

Phys Rev Lett

March 2017

Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.

We study cell navigation in spatiotemporally complex environments by developing a microfluidic racetrack device that creates a traveling wave with multiple peaks and a tunable wave speed. We find that while the population-averaged chemotaxis drift speed increases with wave speed for low wave speed, it decreases sharply for high wave speed. This reversed dependence of population-averaged chemotaxis drift speed on wave speed is caused by a "barrier-crossing" phenomenon, where a cell hops backwards from one peak attractant location to the peak behind by crossing an unfavorable (barrier) region with low attractant concentrations.

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Predicting negative outcomes, such as readmission or death, and detecting high-risk patients are important yet challenging problems in medical informatics. Various models have been proposed to detect high-risk patients; however, the state of the art relies on patient information collected before or at the time of discharge to predict future outcomes. In this paper, we investigate the effect of including data generated post discharge to predict negative outcomes.

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Post-market withdrawal of medications because of adverse drug reactions (ADRs) could result in loss of effective compounds which are effective for treating a specific disease but have unfavorable benefit-to- harm ratio. Recent therapeutic successes have renewed interest in drug combinations, which could work synergistically to improve therapeutic efficacy or work antagonistically to alleviate the risk of the ADRs. However, experimental screening approaches are costly and often can identify only a small number of drug combinations.

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Atrial fibrillation (AF) is a common cardiac rhythm disorder, which increases the risk of ischemic stroke and other thromboembolism (TE). Accurate prediction of TE is highly valuable for early intervention to AF patients. However, the prediction performance of previous TE risk models for AF is not satisfactory.

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Defocus in cathode lens instruments.

Ultramicroscopy

December 2017

Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.

Accurately measuring defocus in cathode lens instruments (Low Energy Electron Microscopy - LEEM, and Photo Electron Emission Microscopy - PEEM) is a pre-requisite for quantitative image analysis using Fourier Optics (FO) or Contrast Transfer Function (CTF) image simulations. In particular, one must establish a quantitative relation between lens excitation and image defocus. One way to accomplish this is the Real-Space Microspot LEED method, making use of the accurately known angles of diffracted electron beams, and the defocus-dependent shifts of their corresponding real-space images.

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Flexible and stretchable electronics are becoming increasingly important in many emerging applications. Due to the outstanding electrical properties of single crystal semiconductors, there is great interest in releasing single crystal thin films and fabricating flexible electronics with these conventionally rigid materials. In this study the authors report a universal single crystal layer release process, called "3D spalling," extending beyond prior art.

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Characterizing fluorocarbon assisted atomic layer etching of Si using cyclic Ar/CF and Ar/CHF plasma.

J Chem Phys

February 2017

Department of Material Science and Engineering, and Institute for Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA.

With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (CF and CHF) and synchronized, plasma-based Ar ion bombardment [D.

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Field effect transistors (FET) have been widely used as transducers in electrochemical sensors for over 40 years. In this report, a FET transducer is compared with the recently proposed bipolar junction transistor (BJT) transducer. Measurements are performed on two chloride electrochemical sensors that are identical in all details except for the transducer device type.

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We report on the photoelectrochemical (PEC) performance and stability of Cu(In,Ga)Se (CIGS)-based photocathodes for photocatalytic hydrogen evolution from water. Various functional overlayers, such as CdS, TiO, ZnSnO, and a combination of the aforementioned, were applied on the CIGS to improve the performance and stability. We identified that the insertion of TiO overlayer on p-CIGS/n-buffer layers significantly improves the PEC performance.

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Background: The effects of an intervention on patients from populations other than that included in a trial may vary as a result of differences in population features, treatment administration, or general setting. Determining the generalizability of a trial to a target population is important in clinical decision making at both the individual practitioner and policy-making levels. However, awareness to the challenges associated with the assessment of generalizability of trials is low and tools to facilitate such assessment are lacking.

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Wafer-scale fabrication of complex nanofluidic systems with integrated electronics is essential to realizing ubiquitous, compact, reliable, high-sensitivity and low-cost biomolecular sensors. Here we report a scalable fabrication strategy capable of producing nanofluidic chips with complex designs and down to single-digit nanometre dimensions over 200 mm wafer scale. Compatible with semiconductor industry standard complementary metal-oxide semiconductor logic circuit fabrication processes, this strategy extracts a patterned sacrificial silicon layer through hundreds of millions of nanoscale vent holes on each chip by gas-phase Xenon difluoride etching.

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Differential privacy concepts have been successfully used to protect anonymity of individuals in population-scale analysis. Sharing of mobile sensor data, especially physiological data, raise different privacy challenges, that of protecting private behaviors that can be revealed from time series of sensor data. Existing privacy mechanisms rely on noise addition and data perturbation.

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Minimum redundancy maximum relevance feature selection approach for temporal gene expression data.

BMC Bioinformatics

January 2017

Center for Data Analytics and Biomedical Informatics, College of Science and Technology, Temple University, North 12th Street, Philadelphia, 19122, PA, USA.

Background: Feature selection, aiming to identify a subset of features among a possibly large set of features that are relevant for predicting a response, is an important preprocessing step in machine learning. In gene expression studies this is not a trivial task for several reasons, including potential temporal character of data. However, most feature selection approaches developed for microarray data cannot handle multivariate temporal data without previous data flattening, which results in loss of temporal information.

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The resonator-induced phase (RIP) gate is an all-microwave multiqubit entangling gate that allows a high degree of flexibility in qubit frequencies, making it attractive for quantum operations in large-scale architectures. We experimentally realize the RIP gate with four superconducting qubits in a three-dimensional circuit-QED architecture, demonstrating high-fidelity controlled-z (cz) gates between all possible pairs of qubits from two different 4-qubit devices in pair subspaces. These qubits are arranged within a wide range of frequency detunings, up to as large as 1.

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Coupling-Enhanced Broadband Mid-infrared Light Absorption in Graphene Plasmonic Nanostructures.

ACS Nano

December 2016

Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, United States.

Plasmons in graphene nanostructures show great promise for mid-infrared applications ranging from a few to tens of microns. However, mid-infrared plasmonic resonances in graphene nanostructures are usually weak and narrow-banded, limiting their potential in light manipulation and detection. Here, we investigate the coupling among graphene plasmonic nanostructures and further show that, by engineering the coupling, enhancement of light-graphene interaction strength and broadening of spectral width can be achieved simultaneously.

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